Coronary Obstruction After Transcatheter Aortic Valve Replacement: From Risk Prediction to Prevention

Abstract

Transcatheter Aortic Valve Replacement in Patients at High Risk of Coronary ObstructionJournal of the Society for Cardiovascular Angiography & InterventionsVol. 1Issue 4100347PreviewCoronary obstruction following transcatheter aortic valve replacement (TAVR) is a life-threatening complication. For patients at elevated risk, it is not known how valve choice is influenced by clinical and anatomic factors and how outcomes differ between valve platforms. For patients at high risk of coronary obstruction, we sought to describe the anatomical and clinical characteristics of patients treated with both balloon-expandable (BE) and self-expanding (SE) valves. Full-Text PDF Open AccessLeft Main Protection During Transcatheter Aortic Valve Replacement With a Balloon-Expandable ValveJournal of the Society for Cardiovascular Angiography & InterventionsVol. 1Issue 4100339PreviewCoronary obstruction during transcatheter aortic valve replacement (TAVR) is a rare, yet life-threatening, complication. The routine use of left main (LM) protection with or without stent placement in high-risk patients remains controversial. The aim of this study was to evaluate the outcomes of LM protection during TAVR and identify anatomic factors associated with need for stent placement. Full-Text PDF Open Access Coronary obstruction, an often fatal but fortunately rare complication of transcatheter aortic valve replacement (TAVR),1Ribeiro H.B. Webb J.G. Makkar R.R. et al.Predictive factors, management, and clinical outcomes of coronary obstruction following transcatheter aortic valve implantation: insights from a large multicenter registry.J Am Coll Cardiol. 2013; 62: 1552-1562Crossref PubMed Scopus (362) Google Scholar,2Ribeiro H.B. Nombela-Franco L. Urena M. et al.Coronary obstruction following transcatheter aortic valve implantation: a systematic review.JACC Cardiovasc Interv. 2013; 6: 452-461Crossref PubMed Scopus (181) Google Scholar is observed in <1% of native aortic valve procedures and 2.5%-3.5% of valve-in-valve (VIV) TAVR cases.3Dvir D. Leipsic J. Blanke P. et al.Coronary obstruction in transcatheter aortic valve-in-valve implantation: preprocedural evaluation, device selection, protection, and treatment.Circ Cardiovasc Interv. 2015; 8e002079Crossref Scopus (139) Google Scholar Risk factors previously described for coronary obstruction include clinical (female sex), procedural (larger TAVR valve sizes, VIV procedure), and anatomical variables including low coronary ostia, shallow sinuses of Valsalva (SOV) or sinotubular junction, elongated leaflets, and the presence of bulky calcified nodules, as well as the projected distances between a virtual valve implant and the coronary ostium, sinuses of Valsalva, or sinotubular junction.1Ribeiro H.B. Webb J.G. Makkar R.R. et al.Predictive factors, management, and clinical outcomes of coronary obstruction following transcatheter aortic valve implantation: insights from a large multicenter registry.J Am Coll Cardiol. 2013; 62: 1552-1562Crossref PubMed Scopus (362) Google Scholar, 2Ribeiro H.B. Nombela-Franco L. Urena M. et al.Coronary obstruction following transcatheter aortic valve implantation: a systematic review.JACC Cardiovasc Interv. 2013; 6: 452-461Crossref PubMed Scopus (181) Google Scholar, 3Dvir D. Leipsic J. Blanke P. et al.Coronary obstruction in transcatheter aortic valve-in-valve implantation: preprocedural evaluation, device selection, protection, and treatment.Circ Cardiovasc Interv. 2015; 8e002079Crossref Scopus (139) Google Scholar, 4Lederman R.J. Babaliaros V.C. Rogers T. et al.Preventing coronary obstruction during transcatheter aortic valve replacement: from computed tomography to BASILICA.JACC Cardiovasc Interv. 2019; 12: 1197-1216Crossref PubMed Scopus (67) Google Scholar, 5Khan J.M. Greenbaum A.B. Babaliaros V.C. et al.The BASILICA trial: prospective multicenter investigation of intentional leaflet laceration to prevent TAVR coronary obstruction.JACC Cardiovasc Interv. 2019; 12: 1240-1241Crossref PubMed Scopus (116) Google Scholar As the presence of a patent bypass graft may protect from adverse consequences of coronary obstruction, individualized decisions regarding risk for coronary obstruction must take into account the interplay of multiple anatomical elements and are best informed by a detailed computed tomography angiographic assessment (CTA) of the aorto-coronary-valvular complex. Given the predictive capability of preprocedural CTA for coronary obstruction and its consequent dismal prognosis, preventive interventional strategies have been developed that include coronary protection (placement of a wire, balloon, and/or stent) and leaflet modification (Bioprosthetic Aortic Scallop Intentional Laceration to prevent Iatrogenic Coronary Artery obstruction during TAVR [BASILICA]) (Figure 1).4Lederman R.J. Babaliaros V.C. Rogers T. et al.Preventing coronary obstruction during transcatheter aortic valve replacement: from computed tomography to BASILICA.JACC Cardiovasc Interv. 2019; 12: 1197-1216Crossref PubMed Scopus (67) Google Scholar In the current issue of JSCAI, 2 manuscripts draw focus on coronary protection during TAVR. First, an analysis of 1925 consecutive TAVR procedures done at Cleveland Clinic shows that left main coronary artery protection with a guidewire, balloon, and/or stent was attempted in 2% of procedures (using balloon-expandable TAVR valves) but that only 10 of 41 total protected patients (25%) required stent placement for threatened coronary obstruction.6Hsiung I. Spilias N. Bazarbashi N. et al.Left main protection during transcatheter aortic valve replacement with a balloon-expandable valve.J Soc Cardiovasc Angiogr Interv. 2022; 1100339Google Scholar CTA predictors for stent implantation were consistent with prior reports with the exception that half of the patients who received left main coronary stents had prior coronary artery bypass graft surgery. Clinical outcomes through 1 ​year were favorable and similar regardless of stent implantation. Second, a 19-center registry of patients deemed “high risk” for coronary obstruction and categorized by pre-emptive coronary protection is presented by Ahmed et al,7Ahmad Y. Oakley L. Yoon S. et al.Transcatheter aortic valve replacement with self-expanding versus balloon expandable valves in patients at high risk for coronary obstruction.J Soc Cardiovasc Angiogr Interv. 2022; 1: 100347Google Scholar with clinical outcomes to 3 ​years stratified by the type of valve implanted (self-expanding valve [SEV] vs balloon-expandable valve). Mortality to 3 ​years was increased following SEV implantation and was ascribed to an increased rate of coronary occlusion; however, significant differences in baseline variables (known predictors for coronary occlusion) between the valve types preclude definitive comparisons from being made. From these 2 reports, we must now consider the important, novel observations that have been made, the limitations of the current analyses, and the unanswered questions that remain. First, the anatomic and procedural predictors of coronary obstruction described in both analyses are not novel but are consistent with prior reports. Second, both studies are retrospective, observational analyses of small subgroups defined by the perceived need for coronary protection during TAVR; however, the criteria for using coronary protection were neither prospectively defined nor uniformly applied (protocolized) in these studies and are obscured by the influence of “operator discretion and clinical judgment.” No independent imaging core laboratory or clinical events committee is identified for either study, leaving the potential for site-determined bias to exist. Further, neither the type of coronary protection (wire, balloon, and/or stent) nor the type of the TAVR valve implanted (SEV or balloon-expandable valve) was randomly assigned. This concern is reflected in the significant differences in baseline variables known to predict coronary occlusion between valve types deployed, which confounds the comparison of outcomes in follow-up (rates of coronary occlusion, mortality). The fact that SEVs were used predominantly in VIV cases likely reflects an attempt to mitigate patient-prosthesis mismatch with a supra-annular design or the desire to maintain device recapturability should coronary artery obstruction occur during deployment. Irrespective of the motivations to use one device over the other, no firm recommendations can be drawn from either study. Both studies reflect the continued need to prospectively define criteria that can more consistently select patients at risk for coronary occlusion and to evaluate preventive strategies. Finally, the addition of detailed CT and procedural information would be invaluable in interpreting the criteria that were used to differentiate patients selected for coronary protection vs those that were not. For example, what was the prevalence of predictors for coronary occlusion among the 1884 patients who had TAVR without pre-emptive coronary protection at the Cleveland Clinic and what was the incidence of coronary occlusion in this population? Similarly, what was the “denominator” for the selected group of 236 TAVR patients with pre-emptive coronary protection from the 19-center registry? What was the prevalence of predictors for coronary occlusion in this larger group and what was the incidence of coronary occlusion stratified by the valve type implanted? This population should be large enough to allow for propensity score matching or inverse probability of treatment weighting statistical techniques to adjust for confounding variables in an observational study. Indeed, very valuable insights would likely be obtained from these larger groups of TAVR patients that were not included in either analysis. Lastly, how many patients in either study had the BASILICA procedure or were referred to surgery and why? What were the outcomes in these patients? Technological enhancements in TAVR technology have reduced procedural complications including paravalvular regurgitation, vascular complications, and pacemaker requirement. Novel TAVR valves in development have lower profiles, sinus cutouts, and anchor rings/locators with the potential to grasp or restrain native/bioprosthetic valve leaflets. Device enhancements will soon enable precise commissural alignment during deployment that will facilitate coronary access should stenting be needed. Whether these novel technologies will favorably impact the likelihood of coronary occlusion remains to be determined. Similarly, simplified leaflet modification or removal strategies may expand the utility of this technique to further reduce the risk for coronary occlusion due to TAVR. Rigorous study of low-frequency clinical events, such as coronary occlusion during TAVR, is challenging, and the “gold standard” for formulating both treatment plans and clinical guidelines (ie, large-scale randomized clinical trials) may not be feasible due to lack of statistical power, inability to randomize, or other considerations. Multicenter collaborations, such as that by Ahmad et al, have the potential to inform practice when sources of bias are minimized. The subject of how to best prevent and/or treat coronary obstruction during TAVR will become increasingly important in the coming decade as structural valve degeneration involving TAVR valves occurs and the ensuing need to perform TAVR in TAVR accelerates. Prospective registries with independent core laboratories for imaging and clinical event adjudication should play an important role in helping to define optimal algorithms for prediction, prevention, and treatment of coronary occlusion associated with TAVR. Dr Garcia is a consultant for Medtronic, Edwards Lifesciences, and Abbott Vascular; reports institutional research grants from Edwards Lifesciences , Abbott Vascular , Gore , and Boston Scientific ; is a proctor for Edwards Lifesciences; and is supported by Harold C. Schott Foundation Endowed Chair for Structural and Valvular Heart Disease. Dr Kereiakes reported no financial interests.