Spanish cardiac catheterization in congenital heart diseases registry. First official report from the ACI-SEC and the GTH-SECPCC (2020)

INTRODUCTION

Currently, transcatheter pulmonary valve implantation is a common procedure in patients with congenital heart disease and dysfunctional right ventricular outflow tract (RVOT).1 Transcatheter balloon-expandable pulmonary valves (Melody by Medtronic Inc., United States, and Sapien by Edwards Lifescience, United States, both with CE marking) have an indication for conduit, native tract, and prosthetic valve implantation.1,3 However, a large number of patients—most with tetralogy of Fallot—who require pulmonary valve implantation are treated with transannular repair or post-commissurotomy pulmonary regurgitation or valvuloplasty for pulmonary valve stenosis. These patients have very pulsatile outflow tracts with larger sizes compared to the ones of current balloon-expandable valves (22 mm and 29 mm for Melody and Edwards, respectively).4 Not even the 32 mm Myval device (Meril Life Sciences Pvt. Ltd., India) without an indication for pulmonary valve implantation would be adequate for the largest RVOTs out there.

Back in April 2022, the self-expanding Venus P-valve (Venus MedTech, China) achieved the CE marking, and became an actual alternative for the largest native tracts.

This is our initial experience with this new transcatheter pulmonary valve at our center and in our country.

METHODS

Valve description

The structure of the Venus-P valve consists of a nitinol stent. Both the leaflets, and the stent coverage are made of porcine pericardium. Nitinol provides the stent with some sort of shape memory so it can adapt to the pulmonary arterial trunk (PAT) without compressing neighboring structures. This valve is available in sizes from 28 mm to 36 mm in diameter with 2 mm increases (figure 1). It can be used with the largest caliber native tracts.5 The Venus P-valve stent has a diabolo-shaped configuration and adds 10 mm to the borders of the central region (figure 1). It is wider in its borders because it has been designed for tubular PAT implantation without distal or pulmonary artery stenosis. Both the central region and the proximal border are covered with porcine pericardium to prevent paravalvular leak. The distal border remains uncovered to avoid occluding the pulmonary arteries (figure 2).6 The stent has radiopaque marks in the distal border of its tubular region and in its proximal border both indicative of the degree of the porcine valve implantation. The valve crimping system on its delivery system is performed under ice water. In these conditions, nitinol becomes softer and can be crimped onto the delivery system (figure 3). The valve is then fixed to the delivery system through 2 small hooks (figure 2). Once the valve has been attached and its size reduced, it is covered with the delivery sheath capsule in such a way that the valve enters the patient fully covered (figure 3 and figure 4) [22-Fr sheaths in 28 mm and 30 mm valves, and 24-Fr sheaths in the largest ones (> 30 mm)]. Once in the pulmonary tree and in the desired location, the delivery sheath capsule will be retracted so the valve can regain its diabolo-shaped configuration when entering blood flow at 36 ºC to 37 °C temperature.

Figure 1. Selection of different valvular sizes with the dimensions of the different parts of the valve. RV, right ventricle.

Figure 2. Image of the Venus P-valve with its typical diabolo-shaped configuration, and coverage of the entire valve leaving both the distal border and the radiopaque markers uncovered.

Figure 3. A: Venus P-valve prior to crimping. B: valve crimping onto the delivery system inside a frozen physiological saline solution with a specific crimping system. C: crimped valve inside the delivery system while covered by a capsule. D: fluoroscopy showing the valve in the delivery system inside the capsule already inserted into the patient’s pulmonary artery.

Procedural description

Cardiac catheterization was performed under general anesthesia while the patient remained intubated and with heparinization at 100 U/kg. Two femoral veins where cannulated, 1 for diagnostic catheterization, cutting, and advance of the valve delivery system, and the other one to perform the follow-up angiography with a pigtail catheter in the RVOT during valve implantation (figure 4). The coronary arteries of all the patients were interrogated through aortograms or selective coronary angiographies with the same 34 mm cutting balloon (Sizing Balloon, AGA Medical Corp., United States) inflated in the RVOT to discard the risk of coronary compression during the procedure (figure 5B). Similarly, the RVOT was cut with the same 34 mm balloon to see if the anatomy was viable and choose the right valve diameter and length. Cutting was considered occlusive when aortic pressure dropped during balloon inflation and the lack of right ventricular (RV) flow to the pulmonary arteries was angiographically confirmed through an intracoronary injection of contrast into the RV during the balloon peak inflation rate (figure 5A).

Figure 4. Valve implantation process. A-D: slow capsule removal so the valve can adapt to the left ventricular outflow tract (LVOT). Angiography monitorization with the pigtail catheter placed in the LVOT. E: final outcomes after valve implantation.

Figure 5. Right ventricular outflow tract cutting with a 34 mm cutting balloon. A: simultaneous angiography in the right ventricle showing the complete occlusion of the RVOT by the balloon that shows a 27 mm notch at stenosis level. B: coronary artery interrogation during cutting balloon inflation without coronary compromise.

Although the imaging modalities performed while planning (computed tomography scan [CT] with or without magnetic resonance imaging (MRI)] inform us on the most appropriate valvular size for each patient, size was picked based on angiography measurements (30° lateral and 30°cranial right anterior oblique), and on the diameter and location of the notch seen in the balloon during occlusive cutting. Balloon cutting allows us to assess the compliance of the PAT, something that is merely suggested on the MRI. Therefore, this is an essential step that should be made before selecting the size of the valve. We select a 2 mm-to-4 mm larger valve compared to the waist of the cutting balloon with a length that should leave the distal border at pulmonary bifurcation level, and the diabolo proximal border at RV level.

The Venus P-valve is implanted without the need for previous stenting to create a landing zone. A Lunderquist high-support guidewire is placed (Cook Medical, Denmark) preferably in the left pulmonary artery. In the presence of stenosis, hypoplasia or unfavorable angle, the guidewire is placed in the right pulmonary artery. The delivery system is advanced through a 65 cm 26-Fr or 24-Fr Dryseal sheath (Gore, W.L. Gore & Associates, Inc., United States) for valves > 30 mm or < 30 mm in diameter, respectively. Once the Dryseal sheath is in position into the selected pulmonary artery, the Venus P-valve delivery system is advanced. Afterwards, the Dryseal sheath is retracted and the correct position of the capsule into the pulmonary artery is verified. Then, the valve is slowly uncovered by withdrawing the capsule (with a clockwise twist of the wheel of the delivery system). As it gradually enters the patient’s bloodstream, the valve regains its normal diabolo-shaped configuration. When its most distal border has been partially adapted to the pulmonary branch, the whole system is then smoothly removed to the PAT and the valve is slowly uncovered while checking—through pigtail catheter injections into the RVOT—that the valve is in position (figure 4). The valve has 2 lines of radiopaque markers to guide implantation. The distal marks that indicate the distal border of the stent tubular region will remain at bifurcation level. The proximal ones should remain at PAT narrowest region or native annulus level (in the location of the notch seen during balloon cutting), thus reducing the risk of embolization. The valve proximal region—10 mm larger than the central one—will remain, in most cases, in the infundibulum of the RV.

Procedure should be performed through a Dryseal sheath to facilitate the maneuverability of the valve delivery system and guarantee safe valve recapture should repositioning be required. The valve can be recaptured until half of its structure has been uncovered.

An aortogram was performed at the end of all procedures (preferably 30° caudal and 20º left anterior oblique) to confirm the lack of coronary artery compression (figure 6).

Figure 6. Final aortogram for coronary artery assessment. Arrows are indicative of the trajectory of the left anterior descending coronary artery.

Patient selection

A previous study through diagnostic catheterization or MRI with or without CT scan was conducted to see whether the anatomy of potentially eligible patients with valve implantation criteria according to the clinical practice guidelines published by the ESC7,8 was ripe for Venus P-valve implantation (figure 7). CT or MRI acquired images were analyzed by Venus Medtech image technicians who video-called our hospital heart team to discuss the convenience of valve implantation and proper valvular size that best suited the patient’s RVOT size. However, the final size was not decided until balloon cutting was used during cardiac catheterization.

Figure 7. Flowchart of patients included in the study.

This first imaging study discarded 5 patients with unsuitable anatomies for this kind of valve: 2 patients with stents and pulmonary artery stenoses, 2 patients with larger RVOTs compared to the sizes recommended for this kind of valve, and 1 patient with pyramid-shaped right ventricular outflow tract.

Study description

This was a prospective study of the first patients treated with Venus P-valve implantation conducted at our center from September 20^th through November 4^th, 2022. These are the very first implantations of this type of valve ever performed in our country.

Inclusion criteria

This study included patients with dysfunctional native RVOTs and an indication for pulmonary valve implantation in whom diagnostic catheterization and cutting test allowed such procedure.

Variables

Demographic and anthropometric data were collected, as well as imaging modality and procedural data to conduct a descriptive analysis of our own experience.

Definitions

Complications were categorized as minor or major. The later were death, potentially life-threatening adverse events, and events requiring surgery (embolization, myocardial perforation, vascular rupture, residual PR, hemolysis, valvular lesion). The former were complications that resolve spontaneously or subside with clinical treatment without potentially fatal outcomes (vascular access problems, fever, neuroapraxias, etc.). Implantation was considered successful in the absence of major complications 24 hours after the procedure.

RESULTS

A total of 8 Venus P-valves were implanted in 8 patients at our center from September 20^th through November 4^th, 2022. The underlying conditions were tetralogy of Fallot (5 patients), pulmonary atresia with ventricular septal defect (1 patient), atrial septal defect with pulmonary stenosis (1 patient), and ventricular septal defect and pulmonary artery banding (1 patient) who required RVOT dilatation in its configuration. All the patients had a transannular patch. Also, all patients had severe pulmonary regurgitation with RV repercussion and PAT dilatation, and were ineligible for transcatheter balloon-expandable valve implantation due to the size of their RVOTs. table 1 shows a overall description of the patients.

Table 1. Overall description of the sample

All patients had dilated PATs as seen on the CT scan or MRI—meaning they were suboptimal candidates for balloon-expandable valve implantation—and tubular PATs without stenoses in, at least, 1 pulmonary artery.

The valves were successfully and uneventfully implanted in all the patients with optimal valvular competence immediately after implantation. A total of 7 implantations were performed via femoral access, and 1 via right jugular vein due to bilateral femoral venous thrombosis. High-support guidewires were placed in the left pulmonary artery (6 cases), and right pulmonary artery (2 cases, 1 due to moderate left pulmonary artery stenosis, and the other one because it was a jugular access). In 7 and 1 cases, respectively, 26-Fr and 24-Fr Dryseal sheaths were used through which implantation occurred. The length of the valves implanted was 25 mm (n = 7) and 30 mm (n = 1).

The median fluoroscopy time was 34 min (interquartile range, 32-37), and the mean radiation dose, 307 mGy/m² (standard deviation, 64.4). We saw an adequate correlation between the CT and MRI measurements of the PAT and the angiography measurements and the cutting balloon.

No severe complications were reported in any of the cases. In 1 case, while the valve was being deployed, 1 of the proximal hooks got trapped in the delivery system due to incomplete removal of the capsule covering the valve. It, however, resolved uneventfully (figure 8). A total of 3 patients had mild thoracic pain 24 hours after implantation not showing elevated troponin levels or ECG abnormalities. Also, 1 patient complained of right scapula pain. One of the patients had common ventricular extrasystole that started right after valve implantation and subsided spontaneously within the next 48 hours not requiring any therapy at discharge. One patient broke a fever 48 hours after implantation without elevation of acute phase reactants.

Figure 8. Arrows indicate, in 2 different projections, that 1 of the attachment hooks is still trapped in the delivery system preventing full valve deployment.

The mean length of stay was 3 days (range 2-4). All patients were discharged on acetylsalicylic acid.

DISCUSSION

Transcatheter pulmonary valve implantation is, currently, a procedure widely performed in the cath labs of congenital coronary care units. Up until now, the valves available—with sizes up to 29 mm—left a significant number of patients without transcatheter therapeutic options available. In some cases, off-label techniques were used (several stents implanted in the PAT to reduce its caliber, stent landing in the left pulmonary artery, etc.) or larger sized balloon-expandable valve implantation with an indication for the aorta (32 mm Myval valve), but not approved for the RVOT.9

Among the main advantages of the Venus P-valve is the possibility or performing one-stage diagnostic catheterizations and valve implantations since previous stenting is not required to create a landing zone (as it was the case with the Melody and Edwards valves in several native tracts). In the most dilated pulmonary arterial trunks (> 24 mm-to-26 mm) one-stage stenting is the gold standard. Then, wait for, at least, 6 weeks until endothelization occurs to minimize the risk of embolization while the valve is being implanted, which requires a second catheterization to implant the valve. Another advantage of the Venus P-valve is how easy it is to use. It is a short procedure with 34 min fluoroscopy times in our cases (shorter to the times reported in our series of native RVOTs and other valves between 40 min and 50 min).

The flexibility of the valve allows PAT adaptation without exerting radial strength on adjacent structures, which is a plus for cases of coronary RVOT-related anatomies.

The short 25 mm valve was used in 7 cases since these patients’ PAT anatomy allowed such length. With longer length, less flexibility for the valve and higher risk of long-term fractures. Up until today, a rate of fractures between 11% and 27% has been reported without associated complications or loss of valvular competence associated with the fractures.5,10

We should pay special attention to the complete removal of the capsule at the end of valve deployment because, if removal is incomplete as it happened with our case (figure 8), hooks can’t be released, and the valve does not get deployed with the corresponding risk of RV embolization.11 To make sure that the system has been released, the hooks should be checked in, at least, 2 different views or projections.6

The diabolo-shaped configuration makes this valve unsuitable for all RVOT anatomies. In cases of distal stenosis at PAT level or at the origin of pulmonary arteries this valve is ill-advised because such stenoses would be limiting the opening of the valve distal border. Regarding this shape—wider in its borders—the onset of transient ventricular extrasystole due to contact with the infundibulum proximal border has been reported. However, to this date, no arrhythmias have ever been reported requiring ablation or cardioversion. In our own experience, only 1 patient had frequent extrasystoles, yet no sustained ventricular arrhythmias were ever reported.

The clinical trial (NCT 02846753) conducted to obtain the CE marking revealed the presence of isolated endocarditis (incidence rate of 1.2%). When long-term follow-up results become available, the actual rates of endocarditis, fractures, and valvular dysfunction will be assessed.

Limitations

The short follow-up of patients is this study main limitation. We’ve been closely monitoring these patients including the use of Holter monitor and imaging modalities (echocardiography, CT scan, and MRI) to properly assess the mid- and long-term evolution of valve implantation. Another limitation is the lack of a control surgical group, which means that comparison can only be made with a historic cohort.

CONCLUSIONS

In conclusion, valve implantation with the new self-expanding Venus P-valve was, in our own preliminary experience, a safe and feasible procedure for valve implantation in very dilated RVOTs with a contraindication for the current balloon-expandable valves with CE marking.

FUNDING

None whatsoever.

AUTHORS’ CONTRIBUTIONS

All the authors contributed to the management and follow-up of the patients, data mining, and approved the manuscript final version for publication. M. Álvarez-Fuente, and M.J. del Cerro designed the study, analyzed data, and drafted the manuscript. HernÁndez, and I. García OrmazÁbal also drafted the manuscript.

CONFLICTS OF INTEREST

None reported.

REFERENCES

INTRODUCTION

Ventricular septal defect (VSD) is one of the most common congenital heart diseases. Its prevalence is 5.3 cases for every 1000 live births.1 It can occur in isolation or as part of a more complex congenital heart disease. Standard therapy is surgical closure with very low morbidity and mortality rates. However, it is no stranger to complications.

Percutaneous closure can be an alternative to surgery in selected anatomies, thus reducing the length of hospital stay, and complications. Both percutaneous and surgical closures have a potential risk of atrioventricular block (AVB)—< 2% for surgical closure, and 0.5% to 6.8% for percutaneous closure.2-5 The high risk of AVB has led to the development of new and more flexible sheaths and devices to close the VSD with less radial strength that minimize the risk of damage to the cardiac conduction system. In this context, the KONAR-MF VSD device occluder (Lifetech, China) was developed. It obtained the CE marking in Europe back in May 2018. It is a low profile, nitinol, self-expanding device with little radial strength and high flexibility in order to adapt to the anatomy of the VSD without exerting any pressure to the adjacent structures. The device is made of 2 discs united at its waist that has a polytetrafluoroethylene membrane. The right disc is simple while the left one has 1 cone attached to it similar the devices that are used to close the ductus arteriosus (figure 1). Each disc has a screw so it can be anchored to the delivery system in such a way that it can be implanted via antegrade (venous) and retrograde (arterial) access. The device comes in several sizes from 5 mm to 14 mm. It is suitable for different VSDs of different sizes, and anatomies (figure 1). The specific sheaths of the delivery system—5-Fr to 7-Fr—are also very flexible, which reduces pressure to the cardiac conduction system during the device implantation maneuvers. Also, it can be implanted through a 7-Fr or 8-Fr guide catheter.

Figure 1. KONAR-MF device (Lifetech, China) with the table of measures available. Data from the device instructions for use.

This is the early experience of 2 Spanish centers using this new device for the closure of VSD.

METHODS

Retrospective review of patients treated with the VSD KONAR-MF occluder device at 2 Spanish centers: Hospital Universitario Ramón y Cajal, Madrid, and Hospital Universitario La Fe, Valencia from February 2020—date of the first implantation procedure in our country—through September 2021. Patients were selected if they had suitable anatomies for percutaneous closure, that is, proper distance to the aortic valve (> 2 mm), lack of posterior prolongation (enough distance to the tricuspid valve), and proportionate size of the devices available. Since this was a short retrospective review, no control group was included.

The patients’ demographic, clinical, and anthropometric data were collected, as well as the echocardiographic anatomy of the defect, the hemodynamic variables of the procedure, and the immediate complications or at the follow-up.

Definitions

Residual shunt was defined as the presence of flow on the color Doppler echocardiography around the device. Flow was categorized into mild (1 mm to 2 mm), moderate (2 mm to 4 mm), or severe (> 4 mm). The presence of flow inside the device was called intradevice shunt and was considered less significant compared to mild shunt.

Complications were categorized as minor or major:

Device implantation was considered successful in the absence of major complications, and severe residual shunt within the next 24 hours.

Description of the procedure

Previous diagnostic cardiac catheterization, and transesophageal echocardiography (TEE) were performed in all the patients. The patients referred for closure had hemodynamic repercussions due to VSD (left ventricular dilatation). Also, the presence of a Qp/Qs ratio ≥ 1.5 was confirmed through a cardiac catheterization performed under general anesthesia while the patient remained intubated.

The size of the device was determined based on the measures of VSD obtained on the TEE, and left ventriculography. The device was 1 mm to 3 mm larger than the defect (figure 2).

Figure 2. Ventricular septal defect (VSD) in a patch in a patient with tetralogy of Fallot. The upper images reveal the presence of the defect both on the transesophageal echocardiography (TEE), and the angiography. The lower images—also from TEE and angiography—reveal the defect being closed after KONAR-MF device implantation (Lifetech, China).

The VSD probing technique, and the device positioning and delivery are not substantially different compared to those used in other device occluders widely discussed in the medical literature.6-9 The interventional procedure was performed under TEE guidance, and the device was released after being properly deployed without severe residual shunt.

Follow-up after closure of ventricular septal defect

Follow-up visits were conducted 1 month, 6 months, and 1 year after closure. After that time, depending on the patient’s baseline condition and clinical situation, follow-up was conducted every 6 or 12 months. Anamnesis, physical examination, electrocardiogram, and echocardiography were performed in these visits. Blood tests were also added to the mix in cases of suspected hemolysis. In the presence of any other symptoms or pathological findings in any of the tests performed, additional studies were conducted like Holter, ergometry or further imaging modalities.

Ethical aspects

In compliance with the current legislation, and since this was a retrospective case review it was not necessary to obtain the patients’ informed consent or approval by the ethics committees of the participant centers.

RESULTS

From February 2020 through June 2021, a total of 7 consecutive procedures of VSD closure were performed at the 2 centers using the KONAR-MF device by successfully implanting this device in 6 out of the 7 patients. Table 1 shows the overall description of the patients. Cases were restrictive defects (native or postoperative) with echocardiographic data of hemodynamic repercussion (left ventricular dilatation) without clinical translation in patients > 8 years.

Table 1. General description of patients treated with percutaneous closure of VSD

The anatomy of VSD was:

The size of the VSD measured on the TEE and angiography was consistent in all the cases except for 1 with a small VSD covered by an aneurysm.

In all the patients, vascular approach was attempted via femoral access (artery and vein); in 6 of them closure was performed via antegrade access, and in 1 patient via retrograde access. Retrograde access was attempted in 1 patient in whom the proper positioning of the right disc could not fully achieved. Finally, closure was successfully completed from the right ventricle, but with longer x-ray image and procedural times. The median x-ray image time was 27 minutes [IQR, 22-50].

There were no immediate complications in any of the cases reported except for 1 embolization in a small VSD with aneurysmal tissue (case #5) where the size of the VSD measured on the TEE and the angiography did not properly correlate. The device embolized to the left pulmonary artery and was retrieved percutaneously through a bailout procedure. The patient was treated with VSD elective surgery a few months later. No hemolysis or vascular complications were reported in the series with a maximum follow-up time of 17 months (median follow-up, 1.2 months; IQR, 0.9-15.5).

Immediate residual shunt was seen in 5 out of the 6 successfully closed VSDs. Two of the patients showed mild intradevice shunt that closed spontaneously within the first 24 hours; in another 2 patients the shunt disappeared 1 month after the procedure, and in the fifth case moderate residual shunt persisted 1 month after the procedure.

All patients were discharged from the hospital within the first 48 hours after the procedure. Three out of the 7 patients were already on acetylsalicylic acid due to their underlying condition while in the remaining 3 with successful closures, treatment with acetylsalicylic acid was started before discharge. Antibiotic prophylaxis was advised for 6 months after closing the residual shunt.

Regarding the clinical course, in 5 out of the 6 patients with successful device implantation and without previous ECG alterations, no conduction abnormalities were seen after closing the VSD. However, 1 case of progression into long-term preexisting postoperative AVB was reported that required pacemaker implantation. This was the case of a patient with repaired tetralogy of Fallot (case #3) who—before the percutaneous closure of the VSD—had advanced AVB of several years of evolution without an indication for pacemaker implantation. Fourteen months after the procedure, the patient required percutaneous pacemaker implantation because data on atrioventricular conduction worsened in Holter, ergometry, and electrophysiological studies.

DISCUSSION

This is a small and heterogeneous series of occluded VSDs with the KONAR-MF device with a short follow-up too. However, we wanted to share our case since this was the first experience in our country using a device that has joined the therapeutic arsenal of occluder devices available for the percutaneous treatment of VSD. Using this device was technically easy and reproducible from the interventional cardiology standpoint. Also, the echocardiographic visualization of the device was rather good from the imaging standpoint (figure 2).

The percutaneous occlusion of VSD with the KONAR-MF device is feasible and effective with complete closure of VSD rates 1 month after implantation of up to 98%,9-12 which has been associated with the possibility of oversizing the device vs the VSD without damaging any adjacent structures given its flexibility.9-12 In our series of a single patient with residual shunt vs 5 patients without it, the rate of occlusion was 83% 1 month after implantation.

Compared to other devices, the advantages attributed to this device are its flexibility and adaptability to the patient’s anatomy, both favorable to minimize complications and increase the efficacy of occlusion. Also, other advantages are the possibility of implanting this device from the aortic side shortening procedural time.

Although, to this date, literature is scarce and only limited to early series of cases, the experience is growing, particularly in Asia.9-14 It has been used in a wide array of clinical scenarios and patients including breastfed babies13 proving effective and safe overall. However, as it occurs with all invasive procedures, it is not stranger to major complications being embolization the most common of all.10,11

The rates of success and major complications (embolization, AVB, and hemolysis) reported with this device are similar—or somehow lower—compared to those reported with other VSD closure devices.11,15 However, the rates of immediate closure are higher compared to those reported with other devices, which would—theoretically speaking—minimize the risk of complications like hemolysis or endocarditis.11,15

Our results are consistent with the series published to this date without cases of hemolysis being reported. The serious complications reported were 1 embolization, and 1 AVB at the follow-up. In our series, embolization was attributed to the fact that a small device was selected as a consequence of the mismatch reported between the VSD size measured on the TEE and on the angiography. The presence of aneurysmal tissue when trying to measure the defect properly was seen as a setback. Future cases should examine the TEE-angiography correlation when measuring the size of VSD.

The medical literature reports 2 cases of permanent AVB (another transient AVB was reported during the procedure contraindicating implantation13): 1 early AVB in the series of Tanidir et al.10 of 98 patients—a rate of AVB of 1%—plus another case deferred for a week14 that made Leong et al.14 review the rate of AVB described in the medical literature with what they referred to as «new» devices. In our sample no cases of rhythm disorders were reported after the procedure was performed in 5 out of 6 cases. However, it is relevant that in a patient with previous advanced AVB, disease progression was reported, which led to pacemaker implantation after closing the defect. Since this patient had tetralogy of Fallot, the device was implanted in a patch without prior direct compression on the cardiac conduction system. Also, this patient had a hemodynamic disorder with right ventricular overload due to acute respiratory failure, and significant stenosis of pulmonary arteries. Given this baseline situation, the worsening AVB cannot be fully attributed to the device although it cannot be discarded either. In any case, the previous presence of conduction abnormalities should be a warning of possible worsening after percutaneous closure of a VSD.

The results of our series should be interpreted in the context of its own limitations (small number of patients and short follow-up period). Although both the versatility of the device and the successful outcomes are encouraging, the presence of serious complications requires a careful approach. Therefore, larger studies with more cases and longer mid-term follow-ups are required to confirm the device safety profile.

CONCLUSIONS

The percutaneous closure of the VSD with the KONAR-MF device emerges as a proper alternative to occlusion with other devices. Also, it is a feasible alternative to surgery for some patients. Also, it stands as an effective occlusion technique in selected defects being the right anatomical assessment of the VSD one of the keys for success. The rates of complete closure and complications of this early sample should improve with more cases, experience, and longer follow-ups. As it occurs with other devices, implanting this device is associated with complications like AVB, and embolization.

FUNDING

None whatsoever.

AUTHORS’ CONTRIBUTIONS

M. Álvarez-Fuente collected the patients’ data and drafted the manuscript. J.I. Carrasco collected the patients’ data and was involved in the review process of the manuscript. B. Insa drafted the manuscript. M. Toledano was involved in the review process of manuscript. E. Peiró participated in the review process of the manuscript. J.P. Sandoval participated as an advisor in the process of drafting the manuscript, as well as the manuscript final review process. M.J. del Cerro drafted the manuscript.

CONFLICTS OF INTEREST

None reported.

REFERENCES

INTRODUCTION

Interventional activity in the management of congenital heart disease in Spain has not been properly evaluated or analyzed to date. The collaboration between the Spanish Society of Cardiology Working Group on Cardiac Catheterization and Interventional Cardiology (ACI-SEC) and the Spanish Society of Pediatric Cardiology and Congenital Heart Disease Working Group on Hemodynamics (GTH-SECPCC) has reactivated and updated a registry that includes all procedures performed in patients, of any age, with congenital heart disease since their fetal stage up to their adult age.

The first report resulting from this new stage of the registry included the activity developed in 2019 and was presented in the 31^st Annual Congress of ACI-SEC that was held online back in December 3-4 of 2020, and in the online administrative meeting of GT-SECPCC held in December 11, 2020.

The current report presented in this article includes the activity developed in 2020 and is the first one to be published; all the information obtained is extremely useful not only to know the volume and results of this activity, but also for the analysis of the implementation of different interventional techniques in Spain and put them in an international context. The continuity of this work will bring us knowledge of its progress in the coming years.

The provision of data was voluntary and took place through an online database. An external company handled and analyzed all the data collected. Members from the ACI-SEC and the GTH-SECPCC boards of directors were involved in the follow-up and process of revising this database; the involvement of both scientific societies—essential to conduct the registry—initiates a very desirable collaboration that should strengthen synergies among interventional cardiologists who work in adult and pediatric areas.

METHODS

This registry includes diagnostic and interventional procedural data from most Spanish centers with significant interventional activity in the field of congenital heart diseases. The submission of data has not been audited and is voluntary. It was conducted through an online questionnaire that only the person responsible from each center can access through ACI-SEC website.1 An external company (Tride, Spain) handled and analyzed the results from the registry in collaboration with members from ACI-SEC and the GTH-SECPCC boards of directors. In case of conflicting data or outside the routine clinical practice, the lead investigator of each center was contacted to verify the information submitted. Given the methodological characteristics of the study and since it was an activity registry only no approval was necessary from any ethics committees. No informed consent was needed either.

RESULTS

Resources and infrastructure

A total of 16 hospitals participated in this registry, all of them from the public healthcare network (annex 1). A total of 30 cath labs with activity in the management of congenital heart disease were included, 7 of which (23.3%) were for pediatric use only. The regular number of days a month dedicated to performing interventional procedures to treat congenital heart diseases in each hospital had a median of 7.5 (4-15) days. However, in 14 (87.5 %) of these centers, emergency cath lab care has become available on a 24-hour basis for patients of any age with congenital heart diseases.

With regard to the medical personnel, a total of 50 interventional cardiologists are involved in this activity 26 of whom (52%) are trained in adult interventional cardiology and 24 (48%) in pediatric interventional cardiology.

Diagnostic procedures

A total of 1043 diagnostic studies were conducted; 55 (5.3%) in infants < 1 month of age; 111 (10.7%) in patients between 1 month and 1 year, 486 (46.7%) cardiac catheterizations in patients between 1 and 18 years of age, and 399 (37.4%) in patients over 18 years of age.

With regard to the type of studies conducted, only 69 (6.6%) were categorized as emergency studies and the remaining ones as scheduled studies. Only 1 serious complication (cardiac tamponade) and no deaths were reported in this group.

Interventional procedures

A total of 1458 therapeutic cardiac catheterizations grouped into 13 different categories and distributed based on age and frequency were reported: only 1 case (0.1%) during the fetal stage, 141 (9.7%) in infants < 1 month, 257 (17.6%) in patients between 1 month and 1 year, 694 (47.6%) in patients between 1 and 18 years of age, and 367 (25.1%) in patients over 18 years of age (table 1).

Table 1. Number of interventional procedures performed and distribution by age groups

A total of 132 of these procedures (9%) were categorized as emergency procedures. A total of 30 serious events directly associated with cardiac catheterization were reported (table 2) including 2 deaths (a 0.1% mortality rate). Also, 17 cases of device embolization were reported 5 of which required surgery.

Table 2. Distribution of complications and deaths reported for each interventional procedure

Percutaneous valvuloplasties

A total of 45 aortic valvuloplasties performed on congenital aortic stenoses were reported including the only case of fetal cardiac intervention in the registry, 25 of these (55.6%) were performed in patients < 1 year 7 of whom (15.6%) were < 1 month, and only 3 (6.7%) were performed in patients > 18 years of age. In 82% of the procedures, the native valves that had not been treated previously were dilated. The procedural success rate was 93.3%, and only 1 death and 1 case of severe aortic regurgitation after dilatation were reported.

A total of 97 pulmonary valvuloplasties were reported. The most numerous age range reported with 61 cases (72.9%) was that of patients < 1 year, 33 of whom (34%) were infants < 1 month, and 11 (11.3%) were patients > 18 years of age. In 95 cases (97.9%) data on the type of valves treated were reported: 80 (84.2%) were native valves, 9 of which (9.4%) were imperforated; only in 3 of these valves ductal stenting was performed to optimize pulmonary output in association with perforation and valvuloplasty. A total of 87 procedures (89.7%) were considered successful. A total of 2 major complications—cardiac tamponade, and arrhythmia with hemodynamic repercussion—were reported. Finally, only 1 case of mitral valvuloplasty was reported on a valve previously treated that turned out a success.

Percutaneous angioplasties

Pulmonary angioplasty is the group with the most cases in this section with 244 cardiac catheterizations; 143 of these (58.6%) were performed in patients between 1 and 18 years of age being this age range the most common one for this procedure. The anatomical substrate of angioplasty was the dilation of branch pulmonary arteries in 176 cases (72.1%), native outflow tract in 38 (15.5%), and the surgical implantation of a pulmonary artery conduit in 30 cases (12.2%). The technical data of 209 procedures were reported (overall percentage, 85.7%): in 55% of these procedures the angioplasty was performed with stenting while in the remaining 45% conventional balloon dilatation was used; no dilatations with cutting balloons were reported. The success rate was 91.4%, and 4 major complications were reported: 2 cases of device embolization, 1 vascular dissection, and 1 case of severe arrhythmia.

A total of 109 aortic angioplasties were reported: in this case the age group with more dilatations was that of patients > 18 years of age with 41 cases (37.6%). A total of 70 procedures (64.2%) were reinterventions while 39 (35.7%) were procedures to treat the native aortic valves. The technical data of 100 cases (overall percentage, 91.7%) were reported with the following distribution: conventional balloon angioplasty, 33%; bare-metal stent implantation, 36%; covered stent implantation, 21%; and redilation of balloon-expandable stent, 10%. A total of 105 procedures (96.3%) were successful. Only 1 case of major complication was reported (1 arterial pseudoaneurysm that required thrombin therapy).

A total of 91 cardiac catheterizations associated with other angioplasties were reported; in this section the anatomical substrate was reported in 63 cases only (69.2%) with special attention to the dilation of the patent ductus arteriosus in 21 cases (33.3%), and surgical fistulae in 5 (7.9%). The success rate reported in this group was 89%; 1 death associated with cardiac catheterization, 1 vascular dissection, and 1 serious neurological event were reported as well.

Shunt closures and other closing procedures

Closure of interatrial communication (CIAC) was the most widely performed interventional procedure in the registry with 377 cases; 220 of these closures (58.4%) were performed in patients > 18 years of age. The type of anatomy of the defect was reported in 374 cases (99.2%): on the one hand, simple CIAC with a single hole, borders > 5 mm, and nonaneurysmal septum in 125 cases (33.4%). On the other hand, complex CIAC and patent foramen ovale in 83 and 166 cases (22.1% and 44.3%, respectively). The most widely used imaging modality to guide the closure was transesophageal ultrasound in 298 procedures (79%) followed by intravascular ultrasound in 56 (14.8%). Angiographic measurement during balloon inflation was used in 79 closures (20.9%). Results were reported in 330 cardiac catheterizations (87.5%) being successful in 97.6% of them; out of the 5 embolizations registered only 1 required surgical bailout.

A total of 199 closures of the patent ductus arteriosus were collected, 132 of which (66.3%) were performed in patients between 1 and 18 years of age, 10 closures (5%) were performed in premature patients, and 8 (4%) in patients > 18 years of age. Occlusion devices were used in 85.2% of the cases reported, and coil-type occlusion devices in the remaining ones. The antegrade venous access was the most widely used of all (69.3%). The success rate reached 96.5% with 5 cases of device embolization, 1 of these eventually requiring surgery.

The third group of shunt closures studied was the closure of interventricular communication (CIVC) including 39 cases, 32 of which (80%) were performed in patients < 18 years of age. This was the distribution of the IVC by anatomical substrate in the 38 closures (97.4%) that included this variable: perimembranous in 26 cases (68.4%), postoperative in 7 (18.4%), and muscular in 5 (13.1%). With regard to the technical data of the procedure, in 56.7% of the cases occluder devices were used while coil-type devices with a controlled release mechanism were used in the remaining ones (40.3%). Only 2 were hybrid procedures. Only 31 cases (79.4%) were considered successful associated with 4 major complications: 3 embolizations (1 of these required surgical bailout), and 1 case of severe arrhythmia as a type of atrioventricular block that prevented the delivery of the occluder device.

Also, data from other occluder devices were collected for a total of 106 cases including the closure of aortopulmonary collaterals in 41 cases (38.6%), the closure of venous collaterals in 18 (16.9%), and the closure of coronary fistulae in 28 cases (26.4%). The materials most widely used were occluder devices (48.5%) followed by coil-type occluder devices (29.1%), and particles (13.5%). The success rate reported reached 99%.

Atrial septostomy

A total of 68 procedures were collected, 56 of which (82.4%) were performed in infants < 1 month. Echocardiography was used as imaging modality guidance in 43 cases (63.3%), and x-ray images in 30 (44.1%). A total of 57 cases (83.8%) were treated with Rashkind balloon atrial septostomy. Also, 8 procedures of septal perforation with radiofrequency, and 7 procedures of septal stenting were reported. The success rate reported reached 100%.

Transcatheter aortic valve implantation

A total of 58 procedures were reported, 29 of which (50%) were performed in patients > 18 years of age. Of these, a total of 55 valves were implanted in the pulmonary position, 2 in the mitral position, and 1 in the tricuspid position. The results of 53 cases (91.4%) were reported with a success rate of 100% and 2 major complications without associated mortality: 1 embolization (that was solved percutaneously) and 1 coronary artery compression.

DISCUSSION

This study is the first one to report on the amount of interventional activity developed in our country for the management of congenital heart disease including pediatric and adult patients. The continuity of this registry and the collaboration between the ACI-SEC and the GTH-SECPCP will improve the quality of this registry in the coming years, and study its evolution in time.

The year 2020 was defined by the COVID-19 pandemic, which also conditioned the way care was provided for the management of cardiovascular disease.2,3 In its annual activity report, the Spanish Society of Cardiology Working Group on Cardiac Catheterization and Interventional Cardiology Registry of 20204 revealed that the reduction in the activity reported was actually not as significant as the one described within the first weeks of confinement, which would confirm a rebound in the activity reported after the first wave of the pandemic. In this registry, the volume of structural heart procedures like transcatheter aortic valve implantation did not fall that much while the volume of procedures like patent foramen ovale actually increased. In line with this trend, we also present a comparison of the data available from the Spanish Cardiac Catheterization in Congenital Heart Diseases Registry from 2019 and 2020 (figure 1). This comparison shows a slight increase in the number of all interventional procedures performed compared to the previous year with an overall increase of 4.1%. We should mention that in the 2019 registry the participation of hospitals dropped (2 centers left the registry) compared to 2020, which puts this information into context.

Figure 1. Comparison between the number of interventional procedures performed in 2019 and 2020. IVC, interventricular communication.

Diagnostic cardiac catheterization provides relevant anatomical and hemodynamic information to guide the treatment required by patients with congenital heart disease through different stages of the disease. Despite the continuous development of other diagnostic techniques in this field, its significance can be seen in the volume of diagnostic procedures reported (1401 cases), which represent 41.6% of the overall number of cardiac catheterizations included in the registry.

Data from 1458 interventional procedures were collected of which 1093 cases (74.9%) correspond to patients < 18 years of age meaning that this activity is basically performed in the pediatric setting m. Only in the closure of interatrial communication, age range > 18 years was the one that accumulated more cases (overall percentage, 58.4%). On the other hand, only 1 interventional procedure (aortic valvuloplasty) was reported during the fetal stage, indicative that the number of patients treated with prenatal percutaneous therapy in our country is still limited.5

Over the last few years different studies have analyzed the risk of serious adverse events associated with cardiac catheterizations performed in pediatric and adult patients with congenital heart diseases;6,7,8 given the variability of its methodology, the rate of serious adverse events also varies (from 2.5% to 7%) and for this same reason, the mortality rate reported is between 0.1% and 2%. In this registry, results and complications were reported in 96% of all interventional procedures performed. In addition, the rates of serious adverse events (2%) and mortality (0.1%) are consistent with those reported in previously cited international studies. Device embolizations—that mostly solved percutaneously—are among the complications most widely reported.

On the other hand, the overall effectiveness of interventional procedures is close to 94.9% (table 3). The least effective technique (79.4%) is the CIVC that is also associated with a high rate of complications (10.2%). All this could be interpreted as a demonstration of how difficulty and demanding it is to perform this procedure. Recently, the experience in our country with the CIVC using the Nit-Occlud device (PFM AG, Germany)—a coil-type device with a controlled release mechanism—has been published.9 It includes the experience of 16 national centers in the management of 116 patients with an 89% efficacy and a rate of major complications of 6.9%.

Tabla 3. Summary of the efficacy of interventional procedures reported

With regard to valvuloplasties, percutaneous dilatation is the most widely accepted technique to treat congenital pulmonary valvular stenosis. Its efficacy reported in this registry (89.7%) may have been conditioned by certain unfavorable anatomical or genetic scenarios disregarded during data duration. In primary care of congenital aortic stenosis there is still an unsolved ongoing debate on whether to go surgical or percutaneous.10 The results reported on the aortic valvuloplasties performed (with a 93.3% efficacy) back up the convenience of using the percutaneous option in our setting. Finally, we should mention that, to this date, mitral valve valvuloplasty is an unusual technique in the congenital heart disease setting.

Within percutaneous angioplasties, the most widely used procedure was the dilation of branch pulmonary arteries that was also the second most widely performed interventional procedure of all in the registry. On the technique used, we should mention that no cutting balloon was used; instead, stent implantation was predominant. The cases reported of aortic angioplasty were mainly reinterventions and only a third treated the native aortic valve. Angioplasty with stenting was the most widely used procedure. Also, bare-metal stent implantation was more common compared to covered stent implantation.

Closure of interatrial communication (CIAC) is the interventional procedure with most cases reported in the registry especially the closure of the patent foramen ovale. The evidence published over the last few years on its utility in the prevention of strokes anticipates its growth in the years ahead.11,12 Transesophageal ultrasound is the most widely used imaging modality to guide the closure of interatrial shunts compared to intravascular ultrasound that is a minority.

Regarding the closure of the patent ductus arteriosus, the use of occluder devices is predominant. In the pediatric setting, the implementation of this technique in premature patients could grow significantly within the next few years after the publication of different studies that support its safety and efficacy profile.13,14

The evolution of both the technique and the indications for transcatheter pulmonary valve implantation, as well as the availability of new valves15,16 widen the number of anatomical scenarios eligible for this procedure. Therefore, it is expected that more patients with right ventricular outflow tract dysfunction will be treated with interventional procedures.

Limitations

The comparison between data collected from this Cardiac Catheterization in Congenital Heart Diseases Registry and data from the Spanish Society of Cardiology Working Group on Cardiac Catheterization and Interventional Cardiology Registry (both from 2020)4 reveals a significant underestimate of some interventional procedures performed in patients > 18 years of age. This would undermine the percentual distribution reported for such procedures between children and adults. Future registries should correct this deficiency and open participation to all centers from our country with some kind of interventional activity to patients with congenital heart diseases, especially adults.

From the methodological point of view, the success parameters of some interventional procedures have not been predefined assuming a uniform criterion in all participant centers. On the other hand, grouping certain techniques like the angioplasty of branch pulmonary arteries, the pulmonary artery conduit, and the native outflow tract can be a confounding factor regarding the assessment of its technical peculiarities and results. Finally, extending the information included on the latest techniques available adds a new asset to the registry and should be reevaluated in future editions.

CONCLUSIONS

This study is the first publication of the Spanish Cardiac Catheterization in Congenital Heart Diseases Registry thanks to the collaboration of the ACI-SEC and the GTH-SECPCC.

Diagnostic cardiac catheterization still plays a key role in the management of patients with congenital heart disease. The most widely used interventional procedures are the CIAC, the angioplasty of branch pulmonary arteries, and the closure of the patent ductus arteriosus. The efficacy and safety data reported on the different interventional techniques used are consistent with the medical literature available. The complications most widely described are embolizations. The CIVC is a technique associated with the lowest success rate and the highest rate of complications in our setting.

Future editions of this registry should encourage the participation of hospitals from our country with interventional activity in the management of congenital heart disease and make the resulting information as truthful and honest as possible.

FUNDING

None whatsoever.

AUTHORS’ CONTRIBUTIONS

All authors contributed substantially to data curation and the process of revising this study. F. Ballesteros Tejerizo, F. Coserría Sánchez, and R. Romaguera were also involved in the drafting of this manuscript.

CONFLICT OF INTERESTS

R. Romaguera, and S. Ojeda Pineda are associate editors of REC: Interventional Cardiology; the journal’s editorial procedure to ensure impartial handling of the manuscript has been followed. The remaining authors had no competing interests to declare.

ANNEX 1. List of centers that participated in the Spanish Cardiac Catheterization in Congenital Heart Diseases Registry

REFERENCES