Michael J. Mack M.D.

Whisenant, B., S. R. Kapadia, M. F. Eleid, S. K. Kodali, J. M. McCabe, A. Krishnaswamy, M. Morse, R. W. Smalling, M. Reisman, M. Mack, W. W. O’Neill, V. N. Bapat, M. B. Leon, C. S. Rihal, R. R. Makkar and M. Guerrero (2020). “One-Year Outcomes of Mitral Valve-in-Valve Using the SAPIEN 3 Transcatheter Heart Valve.” JAMA Cardiol Jul 29. [Epub ahead of print.].

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IMPORTANCE: Bioprosthetic mitral valves are implanted with increasing frequency but inevitably degenerate, leading to heart failure. Reoperation is associated with high morbidity and mortality. Transcatheter mitral valve-in-valve (MViV) using balloon-expandable transcatheter valves has emerged as an alternative for high-surgical risk patients. OBJECTIVE: To assess contemporary outcomes of SAPIEN 3 (Edwards Lifesciences) MViV replacement. DESIGN, SETTING, AND PARTICIPANTS: In this registry-based prospective cohort study of SAPIEN 3 MViV, patients entered in the Society of Thoracic Surgeons/American College of Cardiology Transcatheter Valve Therapy Registry from June 2015 to July 2019 were analyzed. US Centers for Medicare and Medicaid linkage ensured comprehensive collection of death and stroke data. EXPOSURES: Mitral valve-in-valve for degenerated bioprosthetic mitral valves. MAIN OUTCOMES AND MEASURES: The primary efficacy end point was 1-year mortality. The primary safety end point was procedural technical success as defined by the Mitral Valve Academic Research Consortium criteria. Secondary end points included 30-day mortality, New York Heart Association-defined heart failure, and mitral valve performance. RESULTS: A total of 1529 patients (mean [SD] age, 73.3 [11.84] years; 904 women [59.1%]) underwent transseptal or transapical MViV implant at 295 hospitals between June 2015 and July 2019. The mean (SD) Society of Thoracic Surgeons predicted risk of mortality was 11.1% (8.7%). Procedural technical success was achieved for 1480 of 1529 patients (96.8%). All-cause mortality was 5.4% at 30 days and 16.7% at 1 year. Transseptal access was associated with lower 1-year all-cause mortality than transapical access (15.8% vs 21.7%; P = .03). Transcatheter MViV led to early, sustained, and clinically meaningful improvements in heart failure (class III/IV New York Heart Association heart failure of 87.1% at baseline vs 9.7% at 1 year). The mean (SD) mitral valve gradient at 1 year was 7 (2.89) mm Hg. CONCLUSIONS AND RELEVANCE: Transcatheter MViV using the SAPIEN 3 transcatheter heart valve is associated with high technical success, low 30-day and 1-year mortality, significant improvement of heart failure symptoms, and sustained valve performance. Transseptal MViV should be considered an option for most patients with failed surgical bioprosthetic valves and favorable anatomy.

Marquis-Gravel, G., A. Stebbins, A. S. Kosinski, M. L. Cox, J. K. Harrison, G. C. Hughes, V. H. Thourani, T. G. Gleason, A. J. Kirtane, J. D. Carroll, M. J. Mack and S. Vemulapalli (2020). “Geographic Access to Transcatheter Aortic Valve Replacement Centers in the United States: Insights From the Society of Thoracic Surgeons/American College of Cardiology Transcatheter Valve Therapy Registry.” JAMA Cardiol Jun 10;e201725. [Epub ahead of print.].

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IMPORTANCE: Geographic access to transcatheter aortic replacement (TAVR) centers varies in the United States as a result of controlled expansion through minimum volume requirements. OBJECTIVE: To describe the current geographic access to TAVR centers in the United States. DESIGN, SETTING, AND PARTICIPANTS: Observational study from June 1, 2015, to June 30, 2017. United States census data were used to describe access to TAVR center. Google Maps and the Society of Thoracic Surgeons American College of Cardiology Transcatheter Valve Therapy Registry were used to describe characteristics of patients undergoing successful TAVR according to proximity to implanting center. The study analyzed 47 527 537 individuals 65 years and older in the United States and 31 098 patients who underwent successful transfemoral TAVR, were linked to fee-for-service Medicare, and had a measurable driving time. MAIN OUTCOMES AND MEASURES: Median driving distance to a TAVR center. RESULTS: Among 40 537 zip codes in the United States, 490 (1.2%) contained a TAVR center, and among 305 hospital referral regions (HRR), 234 (76.7%) contained a TAVR center. Of the 31 749 patients who underwent successful transfemoral TAVR and were linked to fee-for-service Medicare, 31 098 had a measurable driving time. Mean (SD) age was 82.4 (6.9) years, 14 697 patients (47.3%) were women, and 7422 (23.87%) lived in a rural area. This translated to 1 232 568 of 47 527 537 individuals (2.6%) 65 years and older living in a zip code with a TAVR center and 43 789 169 (92.1%) living in an HRR with a TAVR center. Among 31 749 patients who underwent successful transfemoral TAVR and were linked to fee-for-service Medicare, 31 098 had a measurable driving time. All of these patients (100.0%) underwent their procedure in a TAVR center within their HRR, with 1350 (4.3%) undergoing TAVR in a center within their home zip code. Median driving time to implanting TAVR center was 35.0 minutes (IQR, 20.0-70.0 minutes), ranging from 2.0 minutes to 18 hours and 48 minutes. CONCLUSIONS AND RELEVANCE: Most US individuals 65 years and older live in an HRR with a TAVR center. Among patients undergoing successful transfemoral TAVR, median driving time to implanting center was 35.0 minutes. Within the context of the US health care system, where certain advanced procedures and specialized care are centralized, TAVR services have significant penetration. More studies are required to evaluate the effect of geographic location of TAVR sites on access to TAVR procedures among individuals with an indication for a TAVR within the US population.

Sathananthan, J., P. Green, M. Finn, D. A. Wood, S. Lauck, A. Crowley, M. Alu, S. V. Arnold, D. Cohen, S. Kapadia, M. Mack, V. H. Thourani, S. Kodali, M. Leon and J. G. Webb (2020). “Prognostic implications of baseline 6-min walk test performance in intermediate risk patients undergoing transcatheter aortic valve replacement.” Catheter Cardiovasc Interv Jun 10. [Epub ahead of print.].

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BACKGROUND: While slow gait speed is known to be associated with poor outcomes in patients at high surgical risk who undergo transcatheter aortic valve replacement (TAVR), the prognostic significance of slow gait speed in intermediate risk TAVR patients is poorly understood. OBJECTIVES: We assessed the association between baseline 6-min walk test (6MWT) performance and both 2-year mortality and health status in intermediate risk patients undergoing TAVR as a part of the PARTNER II/S3i studies. METHODS: The association of baseline 6MWT with mortality over 2-years after TAVR was examined using Cox regression; both unadjusted and adjusted for age, left ventricular ejection fraction, coronary artery disease, pulmonary disease, renal insufficiency, and STS score. Patients were divided into four groups according to baseline 6MWT: unable to walk and in three equal tertiles of slow, medium, and fast walkers. Among surviving patients, improvement in 6MWT and quality of life were compared. RESULTS: Among 2,037 intermediate risk TAVR patients (mean age 81.7 years, STS score 5.6%), 8.2% were unable to walk. Baseline 6MWT was associated with all-cause mortality over 2 years (Hazard ratio (HR) 0.87 per 50 m, 95% confidence interval [CI] 0.83 to 0.92, p < .0001). Among surviving patients, the adjusted absolute change in 6MWT at 2 years improved for patients unable to walk (+134.1 m, 95% CI 102.1 to 166 m, p < .0001) and slow walkers (+60.5 m, 95% CI 42.8 to 78.2 m, p < .0001), but was unchanged for medium walkers (-7.3 m, 95% CI -24.3 to 9.6 m, p = .4), and declined for fast walkers (-41.3 m, 95% CI -58.7 to -23.9 m, p < .0001). CONCLUSION: Poor functional capacity is predictive of 2-year mortality in elderly intermediate risk patients undergoing TAVR. However, surviving patients with poor baseline functional capacity had significant improvement in 6MWT performance and quality of life at 2-years following TAVR.

Jawitz, O. K., B. C. Gulack, M. V. Grau-Sepulveda, R. A. Matsouaka, M. J. Mack, D. R. Holmes, Jr., J. D. Carroll, V. H. Thourani and J. M. Brennan (2020). “Reoperation After Transcatheter Aortic Valve Replacement: An Analysis of the Society of Thoracic Surgeons Database.” JACC Cardiovasc Interv Jun 6;S1936-8798(20)30978-X. [Epub ahead of print.].

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OBJECTIVES: The study sought to report the largest series of patients receiving a surgical reoperation after transcatheter aortic valve replacement (TAVR) using the Society of Thoracic Surgeons (STS) Adult Cardiac Surgery Database. BACKGROUND: TAVR has become an effective means of treating aortic stenosis. As TAVR is used in progressively lower-risk cohorts, management of device failure will become increasingly important. METHODS: The STS Adult Cardiac Surgery Database was queried for patients with a history of prior TAVR undergoing surgical aortic valve replacement from 2011 to 2015. Observed-to-expected (O/E) mortality ratios were determined to facilitate comparison across reoperative indications and timing from index TAVR procedure. RESULTS: A total of 123 patients met inclusion criteria (median age 77 years) with an STS Predicted Risk of Mortality of 4%, 4% to 8%, and >8% in 17%, 24%, and 59%, respectively. Median time to reoperation was 2.5 (interquartile range: 0.7 to 13.0) months, and the operative mortality rate was 17.1%. Common indications for reoperation included early TAVR device failures such as paravalvular leak (15%), structural prosthetic deterioration (11%), failed repair (11%), sizing or position issues (11%), and prosthetic valve endocarditis (10%). All pre-operative risk categories were associated with an increased O/E mortality ratio (Predicted Risk of Mortality <4%: O/E 5.5; 4% to 8%: O/E 1.7; >8%: O/E 1.2). CONCLUSIONS: SAVR following early failure of TAVR, while rare, is associated with worse-than-expected outcomes as compared with similar patients initially undergoing SAVR. Continued experience with this developing technology is needed to reduce the incidence of early TAVR failure and further define optimal treatment of failed TAVR prostheses.

Makkar, R. R., P. Blanke, J. Leipsic, V. Thourani, T. Chakravarty, D. Brown, A. Trento, R. Guyton, V. Babaliaros, M. Williams, H. Jilaihawi, S. Kodali, I. George, M. Lu, J. M. McCabe, J. Friedman, R. Smalling, S. C. Wong, S. Yazdani, D. L. Bhatt, J. Bax, S. Kapadia, H. C. Herrmann, M. Mack and M. B. Leon (2020). “Subclinical Leaflet Thrombosis in Transcatheter and Surgical Bioprosthetic Valves: PARTNER 3 Cardiac Computed Tomography Substudy.” J Am Coll Cardiol 75(24): 3003-3015.

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BACKGROUND: Subclinical leaflet thrombosis, characterized by hypoattenuated leaflet thickening (HALT) and reduced leaflet motion observed on 4-dimensional computed tomography (CT), may represent a form of bioprosthetic valve dysfunction. OBJECTIVES: The U.S. Food and Drug Administration mandated CT studies to understand the natural history of this finding, differences between transcatheter and surgical valves, and its association with valve hemodynamics and clinical outcomes. METHODS: The PARTNER 3 (The Safety and Effectiveness of the SAPIEN 3 Transcatheter Heart Valve in Low-Risk Patients With Aortic Stenosis) CT substudy randomized 435 patients with low-surgical-risk aortic stenosis to undergo transcatheter aortic valve replacement (n = 221) or surgery (n = 214). Serial 4-dimensional CTs were performed at 30 days and 1 year and were analyzed independently by a core laboratory. RESULTS: The incidence of HALT increased from 10% at 30 days to 24% at 1 year. Spontaneous resolution of 30-day HALT occurred in 54% of patients at 1 year, whereas new HALT appeared in 21% of patients at 1 year. HALT was more frequent in transcatheter versus surgical valves at 30 days (13% vs. 5%; p = 0.03), but not at 1 year (28% vs. 20%; p = 0.19). The presence of HALT did not significantly affect aortic valve mean gradients at 30 days or 1 year. Patients with HALT at both 30 days and 1 year, compared with those with no HALT at 30 days and 1 year, had significantly increased aortic valve gradients at 1 year (17.8 ± 2.2 mm Hg vs. 12.7. ± 0.3 mm Hg; p = 0.04). CONCLUSIONS: Subclinical leaflet thrombosis was more frequent in transcatheter compared with surgical valves at 30 days, but not at 1 year. The impact of HALT on thromboembolic complications and structural valve degeneration needs further assessment.