The future of interventional cardiology

Over the last few years, left atrial appendage occlusion (LAAO) has gained traction in patients with nonvalvular atrial fibrillation as an alternative to oral anticoagulation to prevent cerebral infarction, especially in patients with some sort of contraindication to these drugs.1

In an article published in REC: Interventional Cardiology, Ruiz-Salmerón et al.2 describe their experience using this technique during the last 10 years. This publication gives us the opportunity to review the cumulative scientific evidence available in this regard that has justified its exponential growth.

In the last national registry published in the United States, the number of physicians and hospitals that perform this intervention has gone from 30 to over 1200 and from 20 to over 400, respectively, within the last 2 years.3 In Spain, according to the registry published by the Interventional Cardiology Association of the Spanish Society of Cardiology, the number of procedures performed within the last 4 years has tripled.4

Left atrial appendage isolation started as a surgical technique back in the 1950s,5 but it was not until the beginning of 2000 when the development of percutaneous interventional procedures finally put this technique on the map.6 However, the turning point was 2009 with the publication of the multicenter and randomized PROTECT AF clinical trial7 that compared the LAAO in over 450 patients implanted with the Watchman device (Boston Scientific, United States) vs conventional treatment with warfarin. It proved the non-inferiority of the intervention for the primary composite of stroke, cardiovascular death or systemic embolism.5 Five years later, the PREVAIL trial8, with a similar design to the PROTECT AF, achieved similar results regarding efficacy, but with success rates over 95% and significantly less common complications (1.9%).

The mid-term follow-up results are even more interesting. At the 3.8-year follow-up, the patients of the PROTECT AF9 experienced a significant benefit in the composite primary endpoint (8.4% vs 13.9%; hazard ratio = 0.61; 95% confidence interval, 0.38-0.97; P = .04) compared to the control group with warfarin. Actually, even all-cause mortality improved in the LAAO group (12.3% vs 18%; hazard ratio = 0.66; 95% confidence interval, 0.45-0.98; P = .04).

Also, the third large randomized clinical trial, the PRAGUE-17,10 that compared LAAO with direct-acting oral anticoagulants in 400 patients, proved the non-inferiority of this procedure compared to new anticoagulants to prevent cardiovascular, neurological or hemorrhagic events associated with atrial fibrillation.

A meta-analysis of these randomized clinical trials proved that LAAO has similar cerebral infarction rates to those of oral anticoagulation (warfarin or new anticoagulants) with significant reductions of cerebral hemorrhages and cardiac and non-cardiac death.11

Added to this, large scale multicenter registries have proven the efficacy and safety of this intervention in patients with contraindications to oral anticoagulation. The EWOLUTION registry of 1021 patients reported a 62% rate of contraindication to oral anticoagulation, a 98.5% success rate, and a 2.7% rate of complications.12 At the 2-year follow-up, cerebral infarction rates of 1.3/100 patients-year (a 83% reduction compared to the historic series) and hemorrhage rates of 2.7/100 patients-year (a 46% reduction compared to the historic series) were reported.13 In line with this, the multicenter registry of the Amulet device (Abbott, United States) that included 1088 patients of whom 83% had contraindications to oral anticoagulation revealed a 99% success rate and a 3.2% rate of complications.14 These results are consistent with almost all the studies published over the last decade.

In our setting we have registries like the one published in this issue of REC: Interventional Cardiology, where Ruiz-Salmerón et al.2 analyze 260 consecutive cases of LAAO in a population of high embolic (CHA₂DS₂-VASc of 4.3 ± 1.6) and hemorrhagic risk (HAS-BLED of 3.7 ± 1.2). They confirmed a 75.5% reduction of embolic risk and a 58.5% reduction of hemorrhagic risk with respect to the risk predicted by both scales. Also, patients with longer follow-up periods (> 4 years in this case) showed a progressive benefit derived from the intervention (rate of events per 100 patients-year: 0.7 vs 2.0, P = .17 for embolisms; and 1.7 vs 4.0, P = .09 for major hemorrhages) compared to those with shorter follow-up periods.

Studies like this are necessary since we don’t have too many studies on long-term experiences with LAAO with mean follow-up periods > 2.5 years. It is only from this long-term follow-up perspective that we will be able to understand the impact of an intervention largely, based on the prophylaxis of the thromboembolic complications that may occur during a patient’s lifetime.

Finally, we should mention that scientific societies like the European Heart Rhythm Association and the European Association of Percutaneous Cardiovascular Interventions15 support the benefits of LAAO in situations of contraindication to oral anticoagulation, high risk of bleeding, cerebral infarction under anticoagulation or even in patients who, after being properly informed, reject oral anticoagulation. However, the current clinical practice guidelines published by the European Society of Cardiology1 still assign a low level of recommendation (IIb-B) for patients with atrial fibrillation contraindicated to long-term courses with oral anticoagulants (eg, patients with intracranial hemorrhages without reversible cause). In any case, the results of 2 ongoing large scale randomized clinical trials of LAAO vs direct-acting oral anticoagulants, the CHAMPION-AF (NCT04394546) and the CATALYST (NCT04226547) will conclusively establish the level of recommendation of this technique in patients without contraindications to oral anticoagulation.

In conclusion, we should assert that the LAAO is an effective and safe technique. With the cumulative data obtained over the last decade, its utility is undeniable in patients with atrial fibrillation who cannot take oral anticoagulation to prevent the occurrence of strokes. Also, clinical trials have proven its advantages vs warfarin, and even the long-term follow-up of these patients has offered significant positive results, even reducing mortality rate compared to oral anticoagulation. The results of the new clinical trials vs direct-acting oral anticoagulants will determine the large-scale future of this procedure.

FUNDING

I. Cruz-González has received research grants from the Instituto de Salud Carlos III (PI19/00658) and the regional health management of the Board of Castille and León (GRS 3031/A/19).

CONFLICTS OF INTEREST

I. Cruz-González is a proctor for Boston Scientific, Lifetech and Abbott, and a consultant for IHT and Qatnamedical. D. González-Calle declared no conflicts of interest whatsoever.

REFERENCES

The management of symptomatic severe aortic stenosis is based on surgical aortic valve replacement (SAVR) or transcatheter aortic valve implantation (TAVI).

In an interesting work recently published on REC: Interventional Cardiology, Núñez-Gil et al.1 studied how the type of hospital and volume of cases impacted the results obtained with both techniques. This was a retrospective analysis with data gathered from administrative sources with the limitations associated with studies based on the Minimum Basic Dataset. Nonetheless, it leaves important messages that should be discussed.

In line with other publications,2 they describe the correlation between casuistry, case volume, and results in terms of mortality and risk-adjusted hospital stays. This article is original and important because in Spain, no study like this has ever been conducted on the association between the volume of TAVIs performed and results.

Also, they confirm the existence of a favorable correlation between better TAVI results and in-hospital «structural» variables like the availability of cardiac surgery intensive care units (CICU). The authors stress the importance behind the finding that there is a correlation between the presence of a CICU and a lower mortality rate with both techniques. However, this impact is greater with TAVI compared to SAVR. Actually, having defined protocols and staff trained in the rapid detection and management of periprocedural complications like vascular access hemorrhages, atrioventricular blocks, renal failure, etc. would explain this correlation.

Data from this study show that the risk-adjusted in-hospital mortality rate is lower in large volume centers and high-level hospitals («type 4»). It is logical to think that large volume PCI-capable centers with all their resources and wide experience in coronary and structural heart procedures will have good results. Performing a high number of procedures reduces procedural complications. However, achieving a solid learning curve first is essential to have good clinical results and increase the cost-effectiveness of the procedures. However, nowadays, the learning curve is shorter with the new devices available.

On the other hand, they found that large volume centers that perform TAVIs and also quite a few SAVRs have a lower mortality rate with percutaneous procedures. The large casuistry with both procedures and the extensive experience of interventional cardiologists and surgeons improves the results. This may be explained by the benefits derived from the mutual collaboration between interventional cardiologists and surgeons regarding the selection of the most appropriate cases for each technique or because surgeons who perform more surgeries have a greater expertise to solve eventual TAVI complications. Still, the need for surgery today is very low.3,4 It may also be suggested that these hospitals have a greater surgical activity because they receive a large number of patients with severe aortic stenosis (some treated with SAVR and others with TAVI).

Hospitals that perform large volumes of TAVIs but very few surgeries also have good results. Therefore, it does not seem to be a factor directly associated with surgical activity per se, but rather with the experience of interventional cardiologists and the writing of proper protocols before, during, and after the procedure.

Consistent with all this, the authors also say that the availability of a CICU is important in the results of TAVI because it guarantees proper treatment after the procedure.

The importance of this article is undeniable, and its findings are very interesting. However, its conclusions should be interpreted with caution. On the one hand, there is too much heterogeneity among the hospitals studied. On the other hand, there may be biases and factors that still remain unstudied. Some of the possible biases may be that patients treated with TAVI in type 3 hospitals without CICU capabilities may have higher comorbidity rates. Also, there are variables not included in the study that may impact the results like the analysis of the valves used or the timeframe of the process analyzed in each hospital, which could also impact the results differently depending on the timing of the learning curve.

The correlation between volume and results has already been proven in other studies.5 However, it seems to decrease in time with more experience, better hospital processes, and more advanced technologies.

Also, there are important additional questions that should be taken into consideration like the analysis of other complications that were not included in the study (eg, need for pacemaker, onset of renal failure, etc.).

Over 4000 annual TAVIs are performed in Spain every year in nearly 110 hospitals by interventional cardiologists who, in collaboration with clinical cardiologists, imaging specialists, and other health professionals—geriatrician, anesthesiologists, intensivists, surgeons, radiologists—achieve excellent results that have been improving throughout the years.

As a consequence of these and other data published, TAVIs should only be performed after proper training, in large enough numbers, and with good results.6,7

In conclusion, the article of Núñez-Gil et al.1 is an interesting study that shows the commitment of interventional cardiologists to optimize the results of TAVI. A commitment that is already a reality in many Spanish cath labs.

FUNDING

No funding was received for this work.

CONFLICTS OF INTEREST

None reported.

REFERENCES

WHAT DO WE KNOW ABOUT FRACTIONAL FLOW RESERVE AFTER STENTING?

The introduction of the concept of fractional flow reserve (FFR) in the mid 90s moved coronary physiology from experimental science to routine use at the cath lab.1-3 Added to the better understanding of basic physiological mechanisms such as self-regulation and compensatory vasodilation and the coronary flow reserve introduced 20 years earlier by Gould et al.,4 FFR has undeniably changed our interpretation of coronary angiograms and had a major influence on the clinical decision-making process, and patient outcomes.3,5,6 This has resulted in the unique adoption of FFR as the only physiological index with a class I A indication for use in the clinical practice guidelines produced by the most important cardiologic societies worldwide.7,8

FFR has taught us that coronary angiography and the anatomic images we can acquire at the cath lab only provide moderately reliable measures of the functional significance of coronary artery disease and myocardial ischemia. Also, there is undeniable proof that the decision-making process based on functional measurements leads to better outcomes compared to angiography alone.3,5,6

In contrast, the interpretation of FFR after coronary intervention is still ambiguous. Basically, we should be aware that the status of a coronary artery immediately after a percutaneous coronary intervention (PCI) changes and is prone to much more variability compared to a situation of chronic stable coronary artery disease. An excellent result of a PCI performed today can change rapidly within hours due to thrombus formation, progressive dissection or other unforeseen complications. Therefore, the FFR measured immediately after a PCI should be interpreted with caution. Also, whereas the ischemic FFR threshold (0.80) in the stable angina has been clearly established, FFR values within the first days, weeks or months after a PCI can change quickly due to the healing process in the coronary artery itself, intimal hyperplasia, thrombus formation, etc. This means that by definition, the FFR after a PCI is more dynamic and that an adequate FFR value immediately after a PCI should be considerably higher than 0.80 to compensate for any intravascular changes that may occur in the short-term.

Therefore, it is not surprising to see FFR values of at least 0.90 in medical literature as indicative of an acceptable PCI result.9,10 Having said that, at the same time we should realize that most post-stent FFR values in earlier studies were obtained in patients with focal stenosis and without much diffuse disease. It is plausible to think that if diffuse disease is present inside a coronary artery, FFR values ≥ 0.90 will probably not be achieved by just stenting a focal stenosis.

Most likely, in such cases, hyperemic pressure pullback recording (whether motorized or not) or a sophisticated variety called hyperemic pressure pullback gradient will better qualify the functional result after stenting. They will also reveal if the remaining gradients inside the coronary artery are due to insufficient stent deployment or more diffuse disease.11

Despite these limitations, the existence of a clear correlation between the FFR values measured immediately after PCI and long-term outcomes is undeniable. This was first described in the FFR-post-STENT Registry of 750 patients that revealed the existence of an inverse correlation between the FFR values measured immediately after the PCI and the rate of restenosis at the 6-month follow-up (figure 1). Such an inverse correlation between high FFR values post-stenting and the mid-term risk of restenosis has been confirmed ever since.12 Still, it is not completely clear if suboptimal FFR values after stenting are due to a focal problem in the stented segment or to diffuse disease elsewhere in the artery. Hyperemic pressure pullback recording and pressure pullback gradient recording have proven that a considerable pressure gradient across the stent is often associated with inappropriate deployments as seen on intravascular ultrasounds or optical coherence tomographies.

Figure 1. Superiority of functional testing compared to angiography alone to predict the outcomes after stenting. A: correlation between post-stenting fractional flow reserve (FFR) and the rate of adverse events at the 6-month follow-up in 750 patients from the FFR-Post-Stent registry. B: correlation between post-stenting angiography and the rate of adverse events at the 6-month follow-up. Reproduced with permission from Pijls et al.9

PATIENT AND VESSEL RELATED PREDICTORS OF POST-PROCEDURAL FFR

At this point, the study conducted by van Zandvoort et al. and recently published on REC: Interventional Cardiology comes into perspective.10 In this study, a large registry of 1000 consecutive patients from 1 large volume cardiac center, the FFR was consistently measured after an angiographically successful PCI without the intention of performing any additional procedures in cases of unexpectedly low FFR values. The authors should be praised for their adherence to this protocol. Afterwards, independent patient and vessel related characteristics were determined as associated with the post-procedural FFR values. Considering that in this study no information was available on the outcomes and that the relationships were not causal per se but associative, a few important lessons can be learned.

In the first place, a very strong predictor of lower FFR values was stent implantation in the left anterior descending coronary artery (LAD). In truly normal LADs, the FFR is not different from other arteries and is very close to 1.00.13 However, even in cases of mild disease, the FFR values measured in the LAD are often more damaged compared to other arteries. This is explained by the fact that the LAD perfusion territory is large. One of the major advantages of FFR with respect to other methodologies that only address a coronary artery injury is that the FFR does not only measure the stenosis itself, but also the extent of the perfusion territory. If a similar stenosis (with similar angiographic, intravascular ultrasound or optical coherence tomography characteristics) is located in a coronary artery with a larger perfusion territory, the FFR will be lower. In this regard, the FFR is actually the link between stenosis severity, coronary blood flow, extent of the myocardial perfusion territory, and myocardial ischemia.14 As such, it is plausible that after a successful PCI, the FFR of the LAD will be somehow lower compared to other coronary arteries.

A second interesting observation is that in women, the FFR measured after apparently successful stenting was often higher compared to the males. Van Zandvoort et al. suggest that this might be due to the fact that in women, microvascular disease plays a more predominant role compared to men. Also, that the generation of a hyperemic gradient within the epicardial coronary artery may be blunted by the presence of microvascular disease.10 To confirm that position, more detailed studies of coronary microvasculature are needed. For many years, the assessment of microvascular disease in a true quantitative way has been too hard to pin down. However, recently developed methodology has changed that as follows.15

SIMULTANEOUS ASSESSMENT OF EPICARDIAL AND MICROVASCULAR DISEASE

Recently, the technique for measuring absolute coronary blood flow and microvascular resistance has been introduced as an adjunctive to FFR measurement. This technique is based on the continuous infusion of a saline solution at a low rate and thermodilution. The technique is simple, elegant, accurate, and operator independent.15

In short, immediately after measuring the FFR, a specifically designed infusion catheter (Rayflow, Hexacath, Paris) is advanced while mounted on the pressure guidewire and placed inside the stent (to study the microvascular resistance of the territory distal to the stent). Then, the infusion of a saline solution at a low rate is started and the absolute coronary blood flow in mL/min is measured in the area of interest using this equation:

Q = Q_i × T/T_i × 1.08

where Q is blood flow in the myocardial territory distal to the stent, Q_i is the infusion rate of the saline solution (mL/min), T_i is the temperature of the infused saline solution (°C), and T is the temperature in the distal coronary artery after mixing blood and the saline solution. T and T_i are expressed as the difference with respect to body temperature.

With infusion rates = 8 to 10 mL/min, resting blood flow values are obtained and with infusion rates = 20 mL/min, maximum hyperemic values are obtained since the saline solution itself at that rate induces maximum hyperemia in a matter of seconds (figure 2; unpublished data).

Figure 2. Example of absolute coronary blood flow and microvascular resistance measurement in left anterior descending coronary artery following routine fractional flow reserve measurement. On the figure upper side, aortic pressure (P_a), and distal coronary pressure (P_d) are shown in red and green, respectively. The blue line represents coronary temperature as a difference with respect to body temperature (T = 0). After starting the infusion of 20 mL/min of a saline solution (Q_i) at room temperature through a dedicated infusion catheter, maximum hyperemia occurs within seconds. Then, after a complete mix of blood and saline solution, a steady-state distal coronary temperature T of 0.32 ^oC below body temperature is achieved. After withdrawing the pressure/temperature sensor from the tip of the infusion catheter, the infusion temperature (T_i) measured is 4.11 ^oC below body temperature. Absolute flow (Q) in the coronary artery is calculated using the equation shown in this article (274 mL/min). Microvascular resistance is simply calculated now by Pd/Q and equals 297 Wood units, which is a normal value for the anterior wall. Since the fractional flow reserve value is also known, the normal reference value of coronary flow can be calculated. All parameters are shown online supported by dedicated software (Coroventis, Sweden).

Immediately after the simultaneous measurement of distal coronary pressure and blood flow values, quantitative microvascular resistance R_µ (Wood units) is estimated. In this same way, epicardial disease (indicated by FFR) and microvascular disease (indicated by R_µ) can be assessed and independently distinguished. The position taken by van Zandvoort et al. suggesting that higher FFR values after PCI are related to a higher microvascular resistance in women could be elegantly validated this way.

WHAT IS THE BEST TECHNIQUE TO MEASURE THE FFR VALUES AFTER A PCI?

In the study conducted by van Zandvoort et al. the FFR values measured after the PCI are only briefly described.10 The authors do not report if hyperemic pressure pullback recordings were performed or other techniques used to assess the entire artery. Also, we should mention that to measure intracoronary pressure, not a single true pressure guidewire was used, but the Navvus system instead (ACIST Medical Systems, Eden Prairie, MN, United States). This system is known to overestimate pressure gradients and underestimate FFR mildly in cases of minimal disease or moderately in cases of more severe disease.16 Also, this system is not validated against regular pressure guidewires in post-PCI vessels.

Nevertheless, the measurements were taken meticulously using IV adenosine at a rate of 140 µg/kg/min, giving the opportunity of an easy and reliable estimation of the FFR under stable conditions. We should mention that only 2 out of 1000 patients showed adenosine intolerance, meaning that the infusion of adenosine had to be interrupted due to harmless adenosine-induced, angina-like chest pain. This underlines the safety profile of IV adenosine infusions as seen in tens of thousands of patients in a myriad of other studies.

In future studies on the meaning and interpretation of post-PCI FFR, it would be adviseable to perform hyperemic pressure pullback recordings as outlined in the first part of this article or use the even more sophisticated technique for whole vessel evaluation after PCI recently introduced by Collet et al. and called hyperemic pressure pullback gradient.11 Obviously, all pressure analyses performed inside the stented coronary artery should preferably be performed at maximum hyperemia since gradients at rest inside the artery are 2 to 3 times smaller. Consequently, the signal-to-noise ratio of a resting pullback recording is 2 to 3 times less sensitive.

In conclusion, although outcome data were not presented which, by the way, was not the objective of the study, the interesting trial conducted by van Zandvoort et al.10 teches us about several interesting patient and vessel related predictors of post-procedural FFR measurement. Also, it anticipates the need for future physiological studies to unravel the different factors involved using new research methods on coronary circulation like hyperemic pressure pullback gradients and truly quantitative microvascular resistance (R_µ) measurements.

FUNDING

No funding whatsoever with regards to this article.

CONFLICTS OF INTEREST

N.H.J. Pijls has received institutional research grants from Abbott and Hexacath. Also, he is a consultant for Abbott, Opsens, and General Electric, and a minor stockholder of Philips, GE, ASML, and Heartflow. L.X. van Nunen declared no conflicts of interest whatsoever.

REFERENCES

It comes as no surprise that the progression of medical training would eventually take a leap into the digital world where we would be able to access information without leaving our working place or the comfort of our homes. Our specialty, interventional cardiology, predominantly visual, has always benefited from the most advanced technology regarding communication. Actually, we have been doing this for years, even in our country: by the mid-1980s, the Madrid Interventional Course (MIC) organized by Dr. J.L. Delcán and Dr. E. García, was already broadcasting live cases via satellite to analyze and discuss new insights with larger audiences compared to those that can fit in a room. These days, live cases are an essential part of the meetings held in our setting (whether international like the ones organized by EuroPCR and TCT or national like the ones held by the Società Italiana di Cardiologia Interventistica [GISE] and the Interventional Cardiology Association of the Spanish Society of Cardiology [ACI-SEC])3. These cases are discussed remotely by panels of experts with a growing interaction with in-person and remote attendees thanks to specific computer tools and social media. But it is not only the broadcast of live cases which benefit from these advances. We have had access to information on late breaking clinical trials through the Internet many times even before in-person meeting where these trials are often presented. Also, we have had access to the recordings of many simultaneous sessions we couldn’t attend in-person but can review later when we have the time.

The situation of the pandemic caused by the new SARS-CoV-2 coronavirus has accelerated this cross over to virtual meetings due to the impossibility of travelling to places and holding large in-person meetings.1 The main in-person cardiology meetings sched­uled for 2020 have been suspended or turned into virtual meetings. The two largest international meetings already mentioned, EuroPCR and TCT, have become virtual meetings. Also, mass meetings like the ones held by the American College of Cardiology, the American Heart Association or the European Society of Cardiology (ESC) have followed in the footsteps of this digital transition. Our sister societies, the Italian GISE and the Portuguese Associação Portuguesa de Intervenção Cardiovascular (APIC) have done the same thing. But, when these restrictions are lifted, will in-person activities like large face-to-face congresses and meetings be gone for good? Let us look at the pros and the cons of virtual and in-person meetings2 (Figure 1).

Figure 1. Pros of virtual meetings compared to face-to-face meetings.

These are the basic strengths of virtual meetings:

Figure 2. Registration comparison of the annual meetings held by the European Society of Cardiology back in 2019 and 2020.

The downsides of virtual meetings are:

• Dependency on technical factors: technical support systems are excellent, but still depend on variables like the Internet bandwidth, the quality of connectivity or the incompatibilities of presentations and videos. After 25 years of use of the DICOM standard for the communication and management of medical imaging we still have issues when we try to play video sequences in virtual meetings.

• To a great extent, the format of these sessions keeps the same structure as face-to-face meetings. The adaptation to the new virtual environment has been more cosmetic than a true reality with the implementation of several technological advances to mimic the in-person experience (avatars, virtual common rooms, chats to replace direct communication). However, fully developed specific methods of communication have not been implemented yet.

• More difficult personal interaction: asynchronous communication and other virtual borders like lack of types of nonverbal communication (beyond emoticons) complicate connectivity among speakers, moderators, and audience. Speakers feel some kind of «digital loneliness» because they don’t receive any feedback from the audience. In turn, the audience experience “digital fatigue” and they can’t remain focused on anything for more than 30 minutes. New systems to encourage audience participation are desperately needed, particularly in the virtual format.

• Agendas, time zones, and time devoted to work: in these virtual meetings it is not unusual to find conflicting time schedules since participants come from all across the world. It is not unusual either that these time schedules invade our spare time or affect our working day. The proliferation of these activities is associated with digital overload that has sometimes been referred to as «death-by-webinars»

• Program sustainability: although our political representatives can’t wait to stop the private sector from funding our medical training programs, the truth is that this is crucial if we want to develop this kind of activity. If some of the activities that used to take place at face-to-face meetings are gone, will support still be the same? Isn’t it more profitable to conduct sponsored meetings and not independent activities?

Those of us who have been trained in the “traditional” meeting environment have a hard time thinking that they can be totally replaced by the virtual format. Here are some of the reasons why:

• Attending a scientific meeting is a comprehensive experience that includes training as well as other activities: research coordination meetings, building up professional relations, consultancy and counseling, etc. It is almost impossible to conduct these activities outside the context of a scientific meeting.

• In this sense, attending a face-to-face meeting is time-bound. It is not always easy to disassociate attendance to these meetings from working or face-to-face obligations (especially when the meeting is held in our own town), but it is actually easier compared to virtual meetings. In our setting there are work permits that can be issued to attend training sessions: could this be applicable to virtual meetings particularly with the current extended time schedules of such events?6

• Most of the advantages seen in the broadcast of contents have long been part of face-to-face meetings. Consequently, most sessions are recorded for immediate broadcast and further reproduction. The same thing happens with in-person and remote audience interaction where the use of social media has proven very useful.

Will the digital gap between the analogical and the digital world, between immigrants and digital natives, between boomers and millennials grow? I don’t think so. Their coexistence will prevail and bring us the best of both worlds: hybrid meetings. If these two worlds were actually ever there…

FUNDING

No funding was received for this work.

CONFLICTS OF INTEREST

A. Pérez de Prado declared having received professional fees for his consultancy work or meetings held for iVascular, Boston Scientific, Terumo, BBraun, and Abbott totally unrelated to this article; he is the current president of the education and learning organization Fundación Epic.

REFERENCES