Debate: MitraClip. The heart failure expert perspective

QUESTION: Are there anatomical reasons to propose distal radial access over conventional radial access?

ANSWER: The answer is yes. The hand has 2 arterial arches: a superficial arch, formed by the ulnar artery and the distal radial artery under discussion here, and a deep arch, formed by the radial and ulnar arteries. It cannot be denied that access via superficial radial artery is useful due to its location in the anatomic snuffbox, over bones such as the scaphoid and trapezium, which make it easily compressible. This results in a 49% lower hemorrhage rate after use and a 49% lower rate of thrombosis1 compared with conventional radial access. Furthermore, in the presence of a superficial radial artery occlusion, either the radial or ulnar artery could later be used as an alternative access site.

However, in my opinion, this access is more difficult to perform, with a longer learning curve and a higher puncture failure rate, which leads to a greater number of cases in which conversion to a different type of access (cross-over) is necessary. On the other hand, conventional radial access is available in the 2 hands, and both ulnar arteries are equally feasible for vascular access, with less tortuosity.

Q.: What evidence exists in favor of distal radial access?

A.: The meta-analysis conducted by the University of Kentucky working group2 with data from 18 randomized clinical trials with 8205 patients found a significantly lower rate of radial artery occlusion (P < .001) and a significantly shorter hemostasis time (P < .001). Although these figures are statistically significant, the rate of radial artery occlusion with conventional access ranges from 4% to 10%, compared with 0.3% to 2.8% with distal access.2 When best clinical practices are implemented with conventional access, such as controlled non-occlusive hemostasis, the occlusion rate is 0.91%.3 These are very low rates, closer to those of our routine clinical practice, which reduces the relevance of that theoretical benefit.

Q.: What specific complications can be associated with this vascular access?

A.: Performing distal radial access is more complex and challenging, likely because we initially learned conventional radial access, and any change feels less comfortable. The study results show several important points:

• – It takes more time to cannulate the artery, puncture duration is longer and more puncture attempts are nedded.4
• – The learning curve is longer (> 200 patients to achieve > 94% success rate).5
• – Cross-over is 3 times more common, requiring an alternative access site to successfully complete the procedure.4 Although there are no serious complications, delays occur in the management of patients in interventional cardiology units.

Q.: Are there situations in which this access might be particularly indicated?

A.: Yes, indeed. Whenever we need to preserve the radial artery patency, the lower risk of occlusion should be considered—for example, in patients requiring an arteriovenous fistula for hemodialysis or in cases where the radial artery may be needed as an arterial graft for coronary artery bypass graft surgery. On the other hand, in patients with prior bleeding complications associated with conventional vascular access, or in those with severe obesity in whom effective compression of the radial artery becomes more difficult, distal radial access may be considered because it is more easily compressible and has lower hemorrhage rates.1

FUNDING

None declared.

STATEMENT ON THE USE OF ARTIFICIAL INTELLIGENCE

None used.

CONFLICTS OF INTERESTS

None declared.

REFERENCES

QUESTION: What are the implications of aortic valve calcification on the outcomes of transcatheter aortic valve implantation (TAVI)?

ANSWER: By design, currently marketed TAVI prostheses require a certain degree of annular calcification to ensure proper fixation. In fact, treating non-calcified valves, such as in pure aortic regurgitation (a scenario for which TAVI has not been approved yet), is associated with a higher risk of malapposition, valve migration, and need for a second prosthesis.1 However, severe valve calcification also poses implantation challenges, as it may compromise the initial procedural success and long-term outcomes.2

Since the planning stage, the presence of severe calcification can hinder the accurate reconstruction of the aortic annular plane and the ability to obtain reliable measurements of its dimensions, thus introducing uncertainty into valve sizing.

Procedurally, severe calcification is associated with a higher risk of immediate complications, such as annular rupture, aortic regurgitation (whether central or paravalvular), and conduction disturbances.3 Furthermore, severe calcification can impede valve crossing and limit the expansion of the prosthesis, which is why valvuloplasty prior to implantation is usually performed to ease valve crossing and allow for greater expansion and better apposition of the prosthesis to the annulus. This increases the number of maneuvers in the aortic root and promotes the embolization of debris, which is associated with a higher risk of ischemic events.

Severe calcification can limit the expansion of the prosthesis and alter leaflet configuration (the so-called pin-wheeling phenomenon), which increases leaflet stress and has been associated with in vitro studies with reduced durability. Furthermore, underexpansion is associated with elevated gradients and a higher rate of central (due to leaflet distortion) and paravalvular (due to annular malapposition) regurgitation.

Q.: What morphological and quantitative aspects of valvular calcification do you assess at your center?

A.: The gold standard for quantifying valvular calcium is computed tomography (CT), which uses either the Agatston score from non-contrast scans or calcium volume from contrast-enhanced CT angiography.4 The degree of calcification, its location, morphology, and distribution asymmetry are key determinants of procedural success and risk of complications. Several studies have associated moderate or severe calcification at the landing zone with a higher risk of paravalvular regurgitation, conduction disturbances, and annular rupture.3 It seems that calcifications protruding into the lumen are most associated with complications, while flatter calcifications have less impact. In addition, severe commissural calcification has been associated with residual regurgitation in that region too.5

The predominant location of calcification on the leaflets body is related to the degree of underexpansion and the prosthesis functionality, which can also influence the risk of coronary compromise in cases where leaflets are calcified at the level of the coronary ostium, especially with low-lying coronary arteries and narrow sinuses.

Ultimately, the interaction between calcium and prosthesis depends on the type of device. Thus, supra-annular prostheses better preserve the geometry of the leaflet when calcification is located at the annulus or left ventricular outflow tract (LVOT), while prostheses with narrower waists and lower radial forces result in less displacement of the leaflets toward the coronaries.

Calcium eccentricity is a major challenge, and the morphology of the valve plays a key role here: bicuspid valves usually show more complex calcification patterns than tricuspid valves do, with greater asymmetry and often calcified raphes that promote asymmetric expansion and prosthesis displacement toward areas of lower resistance, which are features that can also hinder positioning and stable release.

In summary, beyond describing the degree of calcification, what we need to do is target its location (annulus, LVOT, leaflet body, commissures, extension to the sinotubular junction, prominent nodules facing the coronary origins, etc.), the presence of nodules protruding into the lumen or flatter annular-aligned calcifications, as well as their eccentricity.

Q.: How does the degree of calcification affect valve type selection?

A.: Severe calcification increases the risk of complications, particularly paravalvular regurgitation, annular rupture, underexpansion, and conduction disturbances.3 We, therefore, try to select the prosthesis that best matches each case, based on calcium location and characteristics.

Generally, we prefer self-expanding valves and avoid aggressive pre- and post-dilatations in cases with prominent calcium nodules, as their interaction with the balloon increases the risk of dissection or rupture, which are complications with an associated mortality rate close to 100%. Another less common scenario where balloon- expandable valves should be avoided is a small, calcified sinotubular junction relative to the annular size, due to the risk of balloon- induced injury or aortic dissection.

Self-expanding valves, with a more gradual release than balloon- expandable ones, theoretically offer better adaptability to irregular anatomies and may be preferable in annuli with very irregular calcification. However, this is a complex trade-off, as they provide less complete sealing due to their lower radial force but still may reduce the risk of rupture. Balloon-expandable valves may be a very good option when calcification is limited to a specific annular area, especially if it does not protrude excessively.

Additionally, in the presence of significant calcification, it is essential to favor prostheses with an outer sealing skirt and high radial force.

Since LVOT calcification increases the risk of conduction disturbances, we often opt for recapturable valves to optimize final positioning.

In conclusion, valve choice seeks to balance the risks of regurgitation, conduction disturbances, aortic complications, and residual gradients.6

Q.: And how does the degree of calcification affect valve sizing?

A.: Calcification of the leaflet base and LVOT complicates the identification of the cusp nadirs and annular reconstruction, impeding accurate annular boundary definition and precise measurement. Since valve sizing relies primarily on these measurements, excessive calcification may lead to under- or oversizing.

Excessive calcification clearly impacts balloon-expandable valve sizing, generally leading to smaller oversizing (by reducing balloon inflation volume or valve size). However, its influence is not as direct in self-expanding valves where the risk of aortic rupture or dissection is lower due to their reduced radial force, meaning we can aim for standard oversizing or, in cases of borderline annuli between 2 valve sizes, even slightly larger. This is done to achieve better sealing, provided that the anatomy of the sinuses of Valsalva allows for adequate leaflet expansion without a higher risk of coronary compromise. Furthermore, while slight undersizing of balloon-expandable valves can be mitigated by adding a few milliliters of volume to the balloon without compromising its functionality, the problem of an undersized self-expanding valve has no solution because the nitinol material of the valves recovers its factory design at body temperature, even after aggressive post-dilation, which, in turn, perpetuates the problem.

On the other hand, calcium may prevent the adequate expansion and apposition of an oversized valve, thus degrading procedural outcomes and making sizing decisions particularly difficult in many cases.

Q.: Does the procedure differ based on valve calcification?

A.: In cases of severe calcification, we always perform predilatation regardless of the type of valve we’ll be using. Postdilatation is also frequently required, and often more aggressive, to optimize the degree of regurgitation.7

Although optimal positioning is always desired, it is especially critical in “champagne cork”–shaped prostheses designed to achieve optimal oversizing at a certain implant depth; deeper positioning reduces oversizing and increases the risk of regurgitation.

In cases of LVOT calcification, repeated valve movement in and out of the ventricle should be avoided to reduce the risk of conduction system injury.

Finally, significant underexpansion may lead to hemodynamic instability until adequate expansion is achieved via postdilatation. Therefore, one must be ready to support the patient hemodynamically while performing these maneuvers. In this situation, it is of paramount importance to maintain ventricular guidewire access, as crossing a severely underexpanded valve may be difficult. In cases of severe hemodynamic compromise before release, it may be advisable to recapture (if the system allows it) the valve and perform a more aggressive valvuloplasty.

Q.: What are the advantages of self-expanding prostheses in the most severely calcified valves?

A.: In these prostheses, expansion occurs gradually, allowing progressive adaptation to annular irregularities. However, a key limitation compared with balloon-expandable valves is their lower radial force, which increases the risk of regurgitation (a problem noted since the early days of the technique). Next-generation prostheses include features to mitigate this risk. Many incorporate an outer skirt to improve sealing and reduce paravalvular regurgitation. Moreover, several self-expanding valves are now recapturable, allowing assessment of implant height and regurgitation before full release, and repositioning if necessary. Release systems now offer greater stability, more predictable deployment, easier positioning, and fewer recaptures and manipulations in the aortic root.

Secondly, in supra-annular self-expanding valves, normal leaflet configuration is unaffected by calcification at the annulus or LVOT, given their higher positioning, thus generally preserving valve function and excellent hemodynamics even with significant calcification.

Moreover, in severe calcification, the risk of aortic dissection or annular rupture (complications whose mortality rate is close to 100%) is primarily linked to balloon expansion. In this context, a self-expanding valve protects against such complications, provided aggressive pre- or post-dilatation is avoided.

Lastly, self-expanding prostheses typically have a better profile than balloon-expandable ones, enhancing trackability and crossing ability, and facilitating the procedure.

Q.: Are all prostheses the same in this context?

A.: First-generation self-expanding valves were associated with higher rates of paravalvular regurgitation, malapposition, embolization, and need for a second valve in moderate-to-severe calcification. These outcomes have improved parallel to the technical advancements made in the latest versions,8 such as repositionability, recapture capability, and outer skirts. Therefore, in severe calcification, if a self-expanding valve is going to be used, one should prefer models with higher radial force, outer skirt, and repositioning and recapture capabilities. It is essential to remember that even within the same type of valve, several models can have different characteristics that must be well understood.

FUNDING

None declared.

STATEMENT ON THE USE OF ARTIFICIAL INTELLIGENCE

Artificial intelligence was not used.

CONFLICTS OF INTEREST

R. del Valle reports having received speaker fees from Medtronic Ibérica and Mercé V for educational courses, and from Medtronic International for consultancy work.

REFERENCES

QUESTION: What are the implications of aortic valve calcification on the outcomes of transcatheter aortic valve implantation (TAVI)?

ANSWER: Aortic valve calcification has, undoubtedly, been a major influence on TAVI outcomes and the evolving design of heart valves. Severe calcification has been associated with an increased likelihood of complications or poor outcomes, particularly in terms of residual paravalvular leak, need for postoperative pacemaker implantation, or aortic annular rupture, among others.1 Several generations of TAVI prostheses have mainly evolved with the aim of reducing paravalvular leak,2 through the use of skirts and coverings that facilitate sealing by adapting to the irregularities caused by annular and outflow tract calcifications. The goal is to balance sealing capacity with the optimal radial force needed, preventing excessive force that could cause conduction disturbances or, more critically, annular rupture. This emphasizes the critical role of procedural planning, which must account for the extent of calcification in all affected tissues. This meticulous planning, combined with experienced judgment and a deep understanding of the behaviour of each prosthesis is crucial for selecting the correct valve size.

Q.: What morphological and quantitative aspects of valvular calcification do you assess at your center?

A.: In addition to the usual annular measurement, in patients with severe calcification it is important to systematically identify the distribution and extent of calcium:

• – Sinotubular junction: at this level, it is crucial, especially when using a balloon-expandable valve, to determine whether calcification may compromise balloon inflation and, in the worst-case scenario, trigger balloon rupture, resulting in incomplete valve deployment with the risk of embolization, and the possibility of barotrauma-related dissection or aortic rupture in extreme cases. Therefore, it’s important to measure the minimum diameter between the most prominent calcium spicules and the contralateral border to confirm that the size of the balloon inflated with the necessary volume to deploy the selected prosthesis is not larger than that diameter.
• – Coronary ostium: Calcified plaques in the aortic wall near the coronary artery origins can increase the risk of coronary occlusion if displaced during valve deployment. Identifying this risk is crucial for implementing appropriate coronary protection strategies.
• – Sinuses of Valsalva and leaflets: first, it must be determined whether 3 sinuses are present or if we are facing a bicuspid valve, which has typical calcification patterns. The presence of calcified commissural fusions may require balloon predilatation to ensure passage through the valvular plane with the prosthesis and predict the leaflet behavior relative to the coronary arteries. The calcium will redistribute but will not disappear, so if calcium nodules are present on the leaflets occupying the sinus floor, we must consider the depth of the sinuses, and the association between leaflet length and coronary ostium height. If these sizes are suboptimal, the calcified leaflet may evert and occlude the coronary artery detaching from its base, or perforating the aortic wall if space is extremely limited.
• – Aortic annulus: evaluating calcium distribution at this level is crucial, as this is where the prosthesis will exert its greatest radial force. Symmetrical distribution throughout the annular circumference (360°) is rare but undoubtedly one of the most complex scenarios to deal with. In this case, one must assess the depth of calcium into the outflow tract and consider higher or lower implantation depths if it achieves sealing in a less calcified area. If not, an additional measurement beyond the annulus in the outflow tract should be taken to determine if the annular/tract anatomy is straight tubular, flared, or tapered. This information can help us oversize or undersize the prosthesis. However, typically, calcium is more focally distributed, with “teeth” extending toward the outflow tract, especially from the left coronary sinus toward the mitral-aortic continuity. A critical point is often a thinning area where the annulus transitions to the outflow tract, which is precisely where the distal end of the valve is usually positioned. This distribution presents one of the highest risks of rupture, specifically at the calcium thinning site, due to a physical principle: denser calcium regions are more resistant to deformation, so if density is not uniform, energy tends to be released where resistance is at its lowest point, potentially causing rupture. Therefore, planning should account for transitions between highly and minimally calcified zones when making decisions on implantation depth. Heterogeneous calcific density likely increases the risk of complications.

Q.: How does the degree of calcification affect valve type selection?

A: Perhaps the operator’s experience with the chosen valve model is the most influential factor in minimizing complications in heavily calcified scenarios, as operators know the limits of the technology they’re using. However, assuming comparable experience, in my opinion, balloon-expandable valves offer an advantage in expansion capacity and deployment control, allowing for more precise positioning. The combination of a low-recoil alloy and a balloon that inflates progressively and uniformly provides the necessary radial force to overcome calcium resistance while enabling control to stop inflation if high resistance or asymmetry is detected, preventing complications. While the idea that the prosthesis adapts to annular morphology is attractive, despite many self-expanding valves having supra-annular valve mechanisms, the risk of underexpansion is likely high3 requiring aggressive pre- and post-dilatations to create space and prevent recoil. Balloon-expandable technology allows for better sphericity indices in a more controlled and progressive way when appropriate proper implantation technique is used.

Q.: And how does the degree of calcification affect valve sizing?

A: Generally, in these scenarios, the goal with a balloon-expandable valve should be to avoid exceeding 5% oversizing, achieved by adjusting the inflation volume based on the valve nominal size, which usually leads to choosing smaller sizes or inflation volumes than usual for the same annular size in the absence of calcium. Caution in size and inflation volume selection is a great ally in avoiding complications. You can always opt for more aggressive inflations later if necessary and if the initial calcium modification allows. Of note, these valves will gradually expand and modify calcium, so controlled inflation is arguably more important than the final volume used.

Q.: Does the procedure differ based on valve calcification?

A: Technically, several peculiarities should be considered in the presence of a heavily calcified valve:

• – Predilatation: in standard cases, direct implantation of the balloon-expandable valve without predilatation is typical. In high calcium scenarios, predilatation offers several advantages, such as assessing calcium behavior in the sinuses of Valsalva and its relationship with coronary arteries, especially with simultaneous contrast injection. If calcification affects the sinotubular junction, predilatation may help determine the actual risk of balloon rupture during valve release. Most importantly, in cases of calcified commissural fusion, effective predilatation facilitates passage through the valve plane without the need fr aggressive push maneuvers. However, balloon predilatation in such situations may theoretically increase the risk of embolizing calcium debris during inflation, making it a potential indication for cerebral protection devices. Non-homogeneous calcium distribution can cause the asymmetric expansion of the prosthesis, thus shortening more in areas with less or no calcium compared with denser regions. While this does not compromise the functionality of valve, it should be considered when planning very high implantation depths. With balloon-expandable valves, residual leak is usually absent in standard implantation. In cases of high-grade calcification, we must be cautious in pursuing this goal, as it may involve forcing expansion that endangers the patient, especially during postdilatation. Remember that in reducing paravalvular (not central) regurgitation, skirt design is highly effective, and its effect may take a few minutes. Therefore, before aggressive postdilatation, it is advisable to allow time for the distal skirts to take effect.
• – Postdilatation: the first postdilatation should be performed with the same volume as deployment inflation, keeping it fully inflated for, at least, 5 seconds before increasing the volume in subsequent inflations.

If planning reveals a real risk of coronary artery occlusion, protection techniques should be considered.

Q.: What are the advantages of self-expanding prostheses in the most severely calcified valves?

A.: In addition to previously discussed aspects, of note, the ability of balloon-expandable technology to yield excellent results in reducing paravalvular leak,4,5 which is one of the main causes of poor outcomes in calcified prostheses. Moreover, with good planning and proper sizing, highly precise implantations can be achieved, with direct and progressive calcium modification, minimal recoil risk, and less need for postdilatation. The ability to achieve more precise implantations reduces the need for pacemaker implantation as well. Additionally, excellent outcomes have been demonstrated in patients with bicuspid valves, even though these often present with high calcium loads and varied distributions. In conclusion, balloon-expandable technology offers potential advantages in these patients due to its radial strength, control, implantation precision, and lower rates of paravalvular leak and need for pacemaker implantation,6 provided that proper planning goes beyond simple annular sizing, including thorough assessment of calcium distribution and correct size selection, and, above all, adequate knowledge of the prosthesis and the experience needed to handle this complex scenario. Undoubtedly, scientific evidence is needed to determine, beyond opinions, what technology is better, an answer that must come from ongoing clinical trials comparing the new TAVI valves under specific clinical conditions, such as extensive valve calcification.

FUNDING

None declared.

STATEMENT ON THE USE OF ARTIFICIAL INTELLIGENCE

No artificial intelligence was used.

CONFLICTS OF INTEREST

Cristóbal A. Urbano-Carrillo is a proctor for Edwards Lifesciences and participates in advisory groups for Medtronic Spain.

REFERENCES

QUESTION: Clinical practice guidelines have raised the recommendation level for the use of intravascular imaging during percutaneous revascularization procedures for complex lesions to class I. Can you briefly explain the basis for this change?

ANSWER: The clinical benefit of intracoronary imaging-guided revascularization has been evaluated in various clinical studies, including observational registries, randomized clinical trials, and meta-analyses.1,2 However, the publication of 3 large randomized clinical trials has formed the basis for the update of clinical practice guidelines. Firstly, the RENOVATE-COMPLEX-PCI study3 assessed the clinical impact of an intracoronary imaging-guided revascularization strategy (intravascular ultrasound [IVUS] or optical coherence tomography [OCT]) compared with angiography in complex coronary lesions. One of the strengths of this study is its inclusion criteria, which emcompass a heterogeneous yet well-represented group of complex lesions beyond the left main coronary artery, such as true bifurcations, chronic total occlusion, long coronary artery disease, multivessel angioplasty, implantation of multiple stents (more than 3), severe calcification, in-stent restenosis, and ostial lesions. intracoronary imaging-guided revascularization—74% with IVUS and 26% with OCT—was associated with a 36% reduction in the composite endpoint of death, myocardial infarction, and need for revascularization. Similarly, the OCCUPI study4 demonstrated the superiority of OCT vs angiography as a guide in complex procedures, with a 38% reduction in the rate of major adverse cardiovascular events at the 1-year follow-up. Finally, the OCTOBER study5 showed a reduction in the primary endpoint of death, myocardial infarction, and need for revascularization with OCT use in a selected group of complex lesions, such as true coronary bifurcations.

Q.: According to data from the activity registry of the Interventional Cardiology Association of the Spanish Society of Cardiology (ACI-SEC), intravascular imaging is used in 15% of patients treated with percutaneous revascularization. Do you think this new recommendation will increase that figure? What are the barriers to greater implementation of these techniques?

A.: The ACI-SEC activity registry data show a progressive and constant increase in the use of intracoronary imaging, such an increase, yet these data might not meet the expectations6 revealing an unequal adoption of imaging use across centers between 8% and 36%. Robust scientific evidence supporting the recent class I recommendation will undoubtedly have a positive impact on the use of imaging. However, several factors explain the underutilization of these imaging modalities. The first being time consumption: many cath labs handle a heavy caseload, and obtaining images usually increases procedural time. However, systematic use—losing the exceptional nature of imaging—reduces setup time and aids interpretation. Another significant factor is spending: increasingly higher financial allocations are needed for various unit procedures, and imaging is sometimes erroneously omitted as a cost-saving measure in coronary procedures. In this regard, the recent cost-effectiveness analysis conducted in the RENOVATE-COMPLEX-PCI study suggests that intracoronary imaging is more cost-effective than angiography alone in complex coronary lesions reducing cumulative medical spending and improving long-term quality of life.7

Q.: Although, in general, the new recommendation is indicated for complex lesions, it particularly highlights left main coronary artery disease, true bifurcations, and long lesions. Could you elaborate which lesions, in your opinion, would benefit most from the use of intravascular imaging in treatment?

A.: The greatest benefit of intracoronary imaging is observed in procedures associated with more adverse events during follow-up, such as complex lesions, particularly left main coronary artery disease, long coronary disease, and true bifurcations. Whether due to the technical complexity of the intervention or the greater myocardial area at risk, these scenarios yield the most significant benefit from imaging-guided coronary interventions. Future studies would help identify which patients and lesions benefit the most from intracoronary imaging and determine whether differences exist in outcomes between OCT and IVUS. The ILLUMIEN IV study8 sought to evaluate the impact of OCT not only on anatomically complex procedures but also on high-risk populations, such as diabetic patients. Although better stent expansion—minimal stent area—was demonstrated in the OCT-guided group, this did not translate into fewer clinical events compared with angiography at the 2-year follow-up.

Q.: The complexity of interventions is not only determined by anatomical complexity, as we know that there are clinical situations that impose challenges as well. In your opinion, what clinical scenarios or factors should encourage the use of intravascular imaging to optimize procedures?

A.: Traditionally, intracoronary imaging has been associated with guiding complex coronary interventions. However, imaging not only guides interventions but also the diagnosis of coronary artery disease, where it has been playing an increasingly prominent role. On the one hand, imaging is the gold standard in the etiological diagnosis of myocardial infarction with nonobstructive coronary arteries, which presents a major adverse event rate—death or reinfarction—of approximately 5% each year.9 On the other hand, there is growing scientific evidence of the prognostic impact of vulnerable plaques in non-culprit lesions, where intracoronary imaging is essential for evaluation purposes. While there are no current recommendations on which patients benefit from this analysis or what the therapeutic strategy should be, in the coming years, we’ll likely see a more global patient assessment for better risk stratification after a coronary event.

Q.: In general, when do you use intravascular imaging?

A.: The limitations of angiography—which provides only a 2-dimensional luminogram, are well-known. However, as previously mentioned, the greatest benefit of intracoronary imaging lies in the most complex lesions. Theferore, it seems prudent to use imaging in 4 specific scenarios: interventions on the left main coronary artery; stent failure—thrombosis or restenosis—chronic total occlusions; and calcified or ostial lesions. In all these scenarios, imaging characterizes the lesion, guides optimal stent implantation, and determines the percutaneous technique or tools needed during the procedure. However, equally important as the type of lesion is the timing of imaging use, which should be maximized early in the procedure rather than only to confirm a good result. Beyond its role in coronary intervention, imaging has a purely diagnostic utility, particularly in myocardial infarction with nonobstructive coronary arteries, where imaging—mainly OCT—establishes the etiological diagnosis in approximately 50% of the cases.

Q.: When you use imaging, when do you prefer IVUS and when OCT?

A: These techniques do not cancel each other out, but are complementary due to their technological differences. Their use should be adapted to each specific scenario while considering the operator experience and availability. OCT offers faster acquisition and has 10 times higher resolution than the IVUS, enabling clearer visualization of the intimal surface. This turns it into the imaging modality of choice for plaque characterization, especially when studying vulnerable plaques and stent failure. It is also the gold standard for calcium characterization, allowing the quantification of the arc and its thickness in most cases. IVUS, on the other hand, offers greater vessel depth visualization, including deeper layers in the absence of calcium, and does not require blood clearance for acquisition. This makes IVUS particularly useful for left main coronary artery disease, coronary dissection, chronic total occlusion interventions—where subintimal tracking discourages contrast use—and patients with chronic kidney disease, in whom contrast administration must be minimized.

Therefore, the results of the OCTIVUS study10 provided information on the comparative efficacy of OC-T and IVUS-guided coronary intervention. The 2 techniques can be used safe and effectively in most procedures, with comparable short- and long-term outcomes.

FUNDING

None declared.

STATEMENT ON THE USE OF ARTIFICIAL INTELLIGENCE

No artificial intelligence was used in the development of the concept of this manuscript.

CONFLICTS OF INTEREST

None declared.

REFERENCES