Michael J. Mack M.D.

Sannino, A., S. Potluri, B. Pollock, G. Filardo, A. Gopal, R. C. Stoler, M. Szerlip, A. Chowdhury, M. J. Mack and P. A. Grayburn (2019). “Impact of Mitral Stenosis on Survival in Patients Undergoing Isolated Transcatheter Aortic Valve Implantation.” Am J Cardiol 123(8): 1314-1320.

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This study was performed to investigate the prevalence and impact on survival of baseline mitral stenosis (MS) in patients who underwent transcatheter aortic valve implantation (TAVI) due to the presence of severe symptomatic aortic stenosis. This retrospective study included 928 consecutive patients with severe, symptomatic aortic stenosis who underwent TAVI in 2 institutions, from January 2012 to August 2016. Mean follow-up was 40.8 +/- 13.9 months. Based on the mean mitral gradient (MMG) at baseline, 3 groups were identified: MMG <5 mm Hg (n=737, 81.7%); MMG >/=5 and <10 mm Hg (n=147, 16.3%); MMG >/=10 mm Hg (n=17, 1.9%). These latter were more frequently women, with a smaller body surface area, a higher prevalence of atrial fibrillation, chronic obstructive pulmonary disease, and previous history of coronary-artery bypass graft/percutaneous coronary intervention. At baseline, patients with MMG >/=10 mm Hg compared with >/=5 and <10 mm Hg and <5 mm Hg patients had a lower mitral valve area (2.4 +/- 0.94 vs 2.1 +/- 0.86 vs 1.5 +/- 0.44 cm(2)), a lower prevalence of MR >/=2+ (5.9% vs 28.6% and 15.6%, p <0.0001), a higher prevalence of severe mitral annular calcium (70.6% vs 45.6% and 13.0%, p <0.0001) and a higher systolic pulmonary arterial pressure (50.6 +/- 12.1 vs 47.2 +/- 14.5 and 41.6 +/- 14.4, p <0.0001). Despite the low prevalence of MMG >/=10 mm Hg, these patients had higher 5-year mortality compared with the other groups (adjusted hazard ratio 2.91, 95% confidence interval 1.17 to 7.20, p=0.02). In conclusion, severe calcific MS is uncommon in patients who underwent TAVI. Its presence is associated with higher long-term mortality whereas moderate MS is not.

Mack, M. J., M. B. Leon, V. H. Thourani, R. Makkar, S. K. Kodali, M. Russo, S. R. Kapadia, S. C. Malaisrie, D. J. Cohen, P. Pibarot, J. Leipsic, R. T. Hahn, P. Blanke, M. R. Williams, J. M. McCabe, D. L. Brown, V. Babaliaros, S. Goldman, W. Y. Szeto, P. Genereux, A. Pershad, S. J. Pocock, M. C. Alu, J. G. Webb and C. R. Smith (2019). “Transcatheter Aortic-Valve Replacement with a Balloon-Expandable Valve in Low-Risk Patients.” N Engl J Med Mar 17. [Epub ahead of print].

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BACKGROUND: Among patients with aortic stenosis who are at intermediate or high risk for death with surgery, major outcomes are similar with transcatheter aortic-valve replacement (TAVR) and surgical aortic-valve replacement. There is insufficient evidence regarding the comparison of the two procedures in patients who are at low risk. METHODS: We randomly assigned patients with severe aortic stenosis and low surgical risk to undergo either TAVR with transfemoral placement of a balloon-expandable valve or surgery. The primary end point was a composite of death, stroke, or rehospitalization at 1 year. Both noninferiority testing (with a prespecified margin of 6 percentage points) and superiority testing were performed in the as-treated population. RESULTS: At 71 centers, 1000 patients underwent randomization. The mean age of the patients was 73 years, and the mean Society of Thoracic Surgeons risk score was 1.9% (with scores ranging from 0 to 100% and higher scores indicating a greater risk of death within 30 days after the procedure). The Kaplan-Meier estimate of the rate of the primary composite end point at 1 year was significantly lower in the TAVR group than in the surgery group (8.5% vs. 15.1%; absolute difference, -6.6 percentage points; 95% confidence interval [CI], -10.8 to -2.5; P<0.001 for noninferiority; hazard ratio, 0.54; 95% CI, 0.37 to 0.79; P = 0.001 for superiority). At 30 days, TAVR resulted in a lower rate of stroke than surgery (P = 0.02) and in lower rates of death or stroke (P = 0.01) and new-onset atrial fibrillation (P<0.001). TAVR also resulted in a shorter index hospitalization than surgery (P<0.001) and in a lower risk of a poor treatment outcome (death or a low Kansas City Cardiomyopathy Questionnaire score) at 30 days (P<0.001). There were no significant between-group differences in major vascular complications, new permanent pacemaker insertions, or moderate or severe paravalvular regurgitation. CONCLUSIONS: Among patients with severe aortic stenosis who were at low surgical risk, the rate of the composite of death, stroke, or rehospitalization at 1 year was significantly lower with TAVR than with surgery. (Funded by Edwards Lifesciences; PARTNER 3 ClinicalTrials.gov number, NCT02675114.).

Vemulapalli, S., J. D. Carroll, M. J. Mack, Z. Li, D. Dai, A. S. Kosinski, D. J. Kumbhani, C. E. Ruiz, V. H. Thourani, G. Hanzel, T. G. Gleason, H. C. Herrmann, R. G. Brindis and J. E. Bavaria (2019). “Procedural Volume and Outcomes for Transcatheter Aortic-Valve Replacement.” N Engl J Med Apr 3. [Epub ahead of print].

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BACKGROUND: During the introduction of transcatheter aortic-valve replacement (TAVR) in the United States, requirements regarding procedural volume were mandated by the Centers for Medicare and Medicaid Services as a condition of reimbursement. A better understanding of the relationship between hospital volume of TAVR procedures and patient outcomes could inform policy decisions. METHODS: We analyzed data from the Transcatheter Valve Therapy Registry regarding procedural volumes and outcomes from 2015 through 2017. The primary analyses examined the association between hospital procedural volume as a continuous variable and risk-adjusted mortality at 30 days after transfemoral TAVR. Secondary analysis included risk-adjusted mortality according to quartile of hospital procedural volume. A sensitivity analysis was performed after exclusion of the first 12 months of transfemoral TAVR procedures at each hospital. RESULTS: Of 113,662 TAVR procedures performed at 555 hospitals by 2960 operators, 96,256 (84.7%) involved a transfemoral approach. There was a significant inverse association between annualized volume of transfemoral TAVR procedures and mortality. Adjusted 30-day mortality was higher and more variable at hospitals in the lowest-volume quartile (3.19%; 95% confidence interval [CI], 2.78 to 3.67) than at hospitals in the highest-volume quartile (2.66%; 95% CI, 2.48 to 2.85) (odds ratio, 1.21; P = 0.02). The difference in adjusted mortality between a mean annualized volume of 27 procedures in the lowest-volume quartile and 143 procedures in the highest-volume quartile was a relative reduction of 19.45% (95% CI, 8.63 to 30.26). After the exclusion of the first 12 months of TAVR procedures at each hospital, 30-day mortality remained higher in the lowest-volume quartile than in the highest-volume quartile (3.10% vs. 2.61%; odds ratio, 1.19; 95% CI, 1.01 to 1.40). CONCLUSIONS: An inverse volume-mortality association was observed for transfemoral TAVR procedures from 2015 through 2017. Mortality at 30 days was higher and more variable at hospitals with a low procedural volume than at hospitals with a high procedural volume.

Holmes, D. R., Jr. and M. J. Mack (2019). “Rational Dispersion for the Introduction of Transcatheter Mitral Valve Repair Into Clinical Practice: Lessons Learned From TAVR.” JAMA 321(11): 1043-1044.

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The introduction of new medical devices to address unmet clinical needs into the patient care arena, with little or no previous physician experience with the therapy, is a complex process with several important considerations. The questions regarding implementation of transcatheter mitral valve therapy are generally the same as the questions that occurred with TAVR, but with some important nuances. What are the safety and effectiveness profiles, the risk/benefit ratio, and cost-effectiveness of the new therapy compared with other available therapies? In the case of the transcatheter mitral valve repair device for functional mitral regurgitation, additional questions include the following: which specific patient populations may derive the maximal intended benefit of the device (responders), what are the characteristics and qualifications of the centers that care for these patients, what is the optimal geographic dispersion to facilitate patient access, and what specific training and qualifications will the operators need? Surgical and cardiovascular professional societies will need to work closely with the FDA, the Centers for Medicare & Medicaid Services, and device manufacturers to address these issues and develop appropriate methods for rational dispersion to help improve the outcome of patients treated with this new technology. (Excerpt from text, p. 1044; no abstract available.)

Vemulapalli, S., J. D. Carroll, M. J. Mack, Z. Li, D. Dai, A. S. Kosinski, D. J. Kumbhani, C. E. Ruiz, V. H. Thourani, G. Hanzel, T. G. Gleason, H. C. Herrmann, R. G. Brindis and J. E. Bavaria (2019). “Procedural Volume and Outcomes for Transcatheter Aortic-Valve Replacement.” N Engl J Med Apr 3. [Epub ahead of print].

Full text of this article.

BACKGROUND: During the introduction of transcatheter aortic-valve replacement (TAVR) in the United States, requirements regarding procedural volume were mandated by the Centers for Medicare and Medicaid Services as a condition of reimbursement. A better understanding of the relationship between hospital volume of TAVR procedures and patient outcomes could inform policy decisions. METHODS: We analyzed data from the Transcatheter Valve Therapy Registry regarding procedural volumes and outcomes from 2015 through 2017. The primary analyses examined the association between hospital procedural volume as a continuous variable and risk-adjusted mortality at 30 days after transfemoral TAVR. Secondary analysis included risk-adjusted mortality according to quartile of hospital procedural volume. A sensitivity analysis was performed after exclusion of the first 12 months of transfemoral TAVR procedures at each hospital. RESULTS: Of 113,662 TAVR procedures performed at 555 hospitals by 2960 operators, 96,256 (84.7%) involved a transfemoral approach. There was a significant inverse association between annualized volume of transfemoral TAVR procedures and mortality. Adjusted 30-day mortality was higher and more variable at hospitals in the lowest-volume quartile (3.19%; 95% confidence interval [CI], 2.78 to 3.67) than at hospitals in the highest-volume quartile (2.66%; 95% CI, 2.48 to 2.85) (odds ratio, 1.21; P = 0.02). The difference in adjusted mortality between a mean annualized volume of 27 procedures in the lowest-volume quartile and 143 procedures in the highest-volume quartile was a relative reduction of 19.45% (95% CI, 8.63 to 30.26). After the exclusion of the first 12 months of TAVR procedures at each hospital, 30-day mortality remained higher in the lowest-volume quartile than in the highest-volume quartile (3.10% vs. 2.61%; odds ratio, 1.19; 95% CI, 1.01 to 1.40). CONCLUSIONS: An inverse volume-mortality association was observed for transfemoral TAVR procedures from 2015 through 2017. Mortality at 30 days was higher and more variable at hospitals with a low procedural volume than at hospitals with a high procedural volume. (Funded by the American College of Cardiology Foundation National Cardiovascular Data Registry and the Society of Thoracic Surgeons.).