Michael J. Mack M.D.

Mack, M. J. (2019). “RESPONSE: Adapting to Change in a Time of Uncertainty.” J Am Coll Cardiol 74(6): 816-817.

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Historically, the specialty of thoracic surgery has always been, as Han states, one of “paradigm shifts” or, as euphemistically referred to within the specialty, “staying one operation ahead of extinction.” To wit, the specialty began as one to treat tuberculosis until the introduction of sulfa drugs greatly diminished the role of surgery for that disease. The specialty then evolved to the management of rheumatic heart disease for which surgery was a mainstay of treatment until penicillin dramatically reduced the incidence of the disease in developed countries. Next, the central role of surgical coronary revascularization in the treatment of coronary artery disease was significantly modulated by the introduction of percutaneous coronary intervention. Furthermore, many other procedures began as thoracic and cardiac surgical procedures, including bronchoscopy, esophagoscopy, permanent pacemaker, defibrillator implantation, and insertion of intra-aortic balloon pumps, only to have those procedures move to other specialties as the devices become smaller and more easily implanted without general anesthesia. Despite the evolution in the core treatments delivered by our specialty in different eras, we have not become extinct, nor has the specialty diminished; rather, it has survived and thrived . . . As I reflect on the types of operations I was performing when I finished training in 1982, they bear little resemblance to the procedures being performed today. However, that offers little solace to the trainee whose sands are now shifting beneath her/his feet. As the Greek philosopher Heraclitus stated, “the only constant is change.” You cannot worry too much that you chose the wrong career path or succumb to the fear that you will be left behind. Rather, embrace what you love to do and be cognizant of the changes in the ecosystem in which you work. Learn to lead change, embrace that which is currently good, have the vision to determine what needs to change, and have the wisdom to know the difference. To paraphrase Charles Darwin, it’s not the strongest of a species that survives, or the most intelligent, but the one most responsive to change. (Excerpts from text, p. 816-817.)

Thuijs, D., A. P. Kappetein, P. W. Serruys, F. W. Mohr, M. C. Morice, M. J. Mack, D. R. Holmes, Jr., N. Curzen, P. Davierwala, T. Noack, M. Milojevic, K. D. Dawkins, B. R. da Costa, P. Juni and S. J. Head (2019). “Percutaneous coronary intervention versus coronary artery bypass grafting in patients with three-vessel or left main coronary artery disease: 10-year follow-up of the multicentre randomised controlled SYNTAX trial.” Lancet Aug 30. [Epub ahead of print].

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BACKGROUND: The Synergy between PCI with Taxus and Cardiac Surgery (SYNTAX) trial was a non-inferiority trial that compared percutaneous coronary intervention (PCI) using first-generation paclitaxel-eluting stents with coronary artery bypass grafting (CABG) in patients with de-novo three-vessel and left main coronary artery disease, and reported results up to 5 years. We now report 10-year all-cause death results. METHODS: The SYNTAX Extended Survival (SYNTAXES) study is an investigator-driven extension of follow-up of a multicentre, randomised controlled trial done in 85 hospitals across 18 North American and European countries. Patients with de-novo three-vessel and left main coronary artery disease were randomly assigned (1:1) to the PCI group or CABG group. Patients with a history of PCI or CABG, acute myocardial infarction, or an indication for concomitant cardiac surgery were excluded. The primary endpoint of the SYNTAXES study was 10-year all-cause death, which was assessed according to the intention-to-treat principle. Prespecified subgroup analyses were performed according to the presence or absence of left main coronary artery disease and diabetes, and according to coronary complexity defined by core laboratory SYNTAX score tertiles. This study is registered with ClinicalTrials.gov, NCT03417050. FINDINGS: From March, 2005, to April, 2007, 1800 patients were randomly assigned to the PCI (n=903) or CABG (n=897) group. Vital status information at 10 years was complete for 841 (93%) patients in the PCI group and 848 (95%) patients in the CABG group. At 10 years, 244 (27%) patients had died after PCI and 211 (24%) after CABG (hazard ratio 1.17 [95% CI 0.97-1.41], p=0.092). Among patients with three-vessel disease, 151 (28%) of 546 had died after PCI versus 113 (21%) of 549 after CABG (hazard ratio 1.41 [95% CI 1.10-1.80]), and among patients with left main coronary artery disease, 93 (26%) of 357 had died after PCI versus 98 (28%) of 348 after CABG (0.90 [0.68-1.20], pinteraction=0.019). There was no treatment-by-subgroup interaction with diabetes (pinteraction=0.66) and no linear trend across SYNTAX score tertiles (ptrend=0.30). INTERPRETATION: At 10 years, no significant difference existed in all-cause death between PCI using first-generation paclitaxel-eluting stents and CABG. However, CABG provided a significant survival benefit in patients with three-vessel disease, but not in patients with left main coronary artery disease. FUNDING: German Foundation of Heart Research (SYNTAXES study, 5-10-year follow-up) and Boston Scientific Corporation (SYNTAX study, 0-5-year follow-up).

Mack, M. J. and M. B. Leon (2019). “Transcatheter Aortic-Valve Replacement in Low-Risk Patients. Reply.” New England Journal of Medicine 381(7): 684-685.

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Kaul’s major concern is that there were fewer primary end-point events in the Placement of Aortic Transcatheter Valves (PARTNER) 3 trial than in earlier trials. He states that the inclusion of rehospitalization in the composite primary end point led it to become the main driver for the superiority of TAVR and also introduced a bias against surgery owing to the number of concomitant procedures performed in the surgical group. In PARTNER 3, the primary end point was specifically chosen to account for the lower event rate expected in low-risk patients and was powered on the basis of anticipated event rates from previous PARTNER trials. The sample size assumed a composite end-point event rate of 16.6% in the surgery group and 14.6% in the TAVR group. In fact, the primary event rates were 15.1% and 8.5%, respectively, and all components of the composite end point directionally favored TAVR. Rehospitalization was included because we believe it is a meaningful adverse outcome in low-risk patients, and it has been used as the sole primary end point in other recent trials. The higher rate of concomitant procedures in surgery (26.4% vs. 7.9%), mentioned both by Kaul and by Perella and Anwar, is a reflection of real-world surgical practice. The heart team at each site concluded before randomization that either approach, surgery or TAVR, would yield the best possible outcome. Since those patients who had a concomitant procedure did not have a higher rate of primary end-point events, there was no bias against surgery. Data available at the 10-year follow-up should give further insight into the risks and benefits of each approach, especially among patients who underwent concomitant coronary revascularization. Baldetti et al. noted a higher incidence of new-onset LBBB among patients who underwent TAVR, which suggests the possibility of the unfavorable prognostic effect of mechanical dyssynchrony. We agree and have recently published an analysis of patients in the earlier, higher-risk trials that shows worse left ventricular systolic function and more adverse clinical outcomes in patients with new LBBB. Precisely for these reasons, all patients will be followed with clinical, echocardiographic, and electrocardiographic assessment annually for 10 years. Finally, Savas et al. express concern that the higher rate of mild paravalvular leak with TAVR may lead to increased late mortality, citing data from a PARTNER trial involving high-risk patients. Although we share their concern, subsequent analyses of intermediate-risk patients have not shown an increase in mortality with mild paravalvular regurgitation.4 Nonetheless, all patients will be carefully followed for 10 years to address this concern. (Authors’ response to several commentaries on their previously published studies: Mack MJ, Leon MB, Thourani VH, et al. Transcatheter aortic-valve replacement with a balloon-expandable valve in low-risk patients. N Engl J Med 2019;380:1695-1705 and Leon MB, Smith CR, Mack MJ, et al. Transcatheter or surgical aortic-valve replacement in intermediate-risk patients. N Engl J Med 2016;374:1609-1620.)

Kaneko, T., V. H. Thourani, G. Ailawadi, M. B. Leon, M. J. Mack and G. H. L. Tang (2019). “Transseptal Access-Gateway to Transcatheter Mitral Interventions.” Ann Thorac Surg 108(3): 654-656.

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Over the past 8 years, we have witnessed a significant growth of transcatheter aortic valve replacement (TAVR) replacing 1 of our most commonly performed surgeries, the surgical aortic valve replacement for severe aortic stenosis. In 2017, for the first time, the number of TAVRs performed exceeded surgical aortic valve replacements with or without coronary revascularization. Recently, 2 randomized studies comparing surgical aortic valve replacement with TAVR in low-risk patients with severe aortic stenosis revealed superiority on mortality and disabling stroke with a balloon-expandable valve, and non-inferiority with a self-expanding valve will most definitely favor an increase in transcatheter aortic valve procedures. With the success in TAVR, industry is searching for the next frontier. In 2015, Edwards Lifesciences (Irvine, CA) bought a start-up company, CardiAQ for $200 million, and Medtronic (Minneapolis, MN) bought another start-up company, Twelve, for $458 million. These start-up companies have one thing in common—they both created new technology for transcatheter mitral valve replacement. Investment in these start-up companies clearly shows the direction of the next chapter in the treatment of structural heart disease. (Excerpt from text, p. 654; no abstract available.)

Rodes-Cabau, J., K. A. Ellenbogen, A. D. Krahn, A. Latib, M. Mack, S. Mittal, G. Muntane-Carol, T. M. Nazif, L. Sondergaard, M. Urena, S. Windecker and F. Philippon (2019). “Management of Conduction Disturbances Associated With Transcatheter Aortic Valve Replacement: JACC Scientific Expert Panel.” J Am Coll Cardiol 74(8): 1086-1106.

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Despite major improvements in transcatheter aortic valve replacement (TAVR) periprocedural complications in recent years, the occurrence of conduction disturbances has not decreased over time and remains the most frequent complication of the procedure. Additionally, there has been an important lack of consensus on the management of these complications, which has indeed translated into a high degree of uncertainty regarding the most appropriate treatment of a large proportion of such patients along with major differences between centers and studies in pacemaker rates post-TAVR. There is therefore an urgent need for a uniform strategy regarding the management of conduction disturbances after TAVR. The present expert consensus scientific panel document has been formulated by a multidisciplinary group of interventional cardiologists, electrophysiologists, and cardiac surgeons as an initial attempt to provide a guide for the management of conduction disturbances after TAVR based on the best available data and group expertise.