Michael J. Mack M.D.

Badhwar, V., M. Alkhouli, M. J. Mack, V. H. Thourani and G. Ailawadi (2019). “Reply: Surgical and transcatheter therapy for secondary mitral regurgitation.” J Thorac Cardiovasc Surg 158(3): e93-e95.

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Recent clinical trials have added valuable information, as well as controversy, for the surgical and transcatheter management of secondary mitral regurgitation (MR). One thing is clear, secondary MR is not a binary disease state. It is not present or absent. It is a pathoanatomic continuum. Based on the evidence, a recent grading system has been proposed to suggest targeted surgical and transcatheter therapy of secondary MR based on pathoanatomy and comorbid risk. The experience of Nappi and colleagues with a subvalvular adjunct to restrictive annuloplasty informed a recent letter to the Editor. They make a few important points. First, they re-emphasize the importance of revascularization in ventricular remodeling and suggest potential improvement of secondary MR when viable myocardium is noted. Second, they attest that for patients with nonviable myocardium, a restrictive annuloplasty combined with a subvalvular sling repair should be considered. Finally, by the title of their letter they suggest that a proposed grading system for mitral valve (MV) intervention forfeits the opportunity for MV repair as an important therapy [. . .] Nappi and colleagues are to be congratulated for their steadfast outcome reporting of adjunctive subvalvular papillary muscle repair and their institutional results are admirable, yet their recent identification of failures of this technique indicate that it may not actually be for everyone. They report failures of MV annuloplasty and subvalvular repair with MV tenting area ≥ 3.1 cm2 and left ventricle end-diastolic diameter ≥ 64 mm. In fact, their findings that patients with significant left ventricle remodeling and MV tenting have a higher incidence of recurrent MR aligns precisely with the recently proposed grading system. The cumulative evidence and surgical outcomes with MV repair and replacement in secondary MR do not amount to forfeiture of this complex disease state to transcatheter therapy. To the contrary, the proposed grading system suggests that MV repair still has a role in at least Grade I secondary MR in patients the heart team believes may benefit from surgical therapy. Perhaps MV annuloplasty and subvalvular repair may have a role in Grade II secondary MR, provided the patient does not have the predictors identified by Nappi and colleagues. (Excerpts from text of authors’ reply to letters concerning their article, Badhwar V., Alkhouli M., Mack M.J., Thourani V.H., and Ailawadi G.: A pathoanatomic approach to secondary functional mitral regurgitation: evaluating the evidence. J Thorac Cardiovasc Surg 2019; 158: pp. 76-81.)

Chhatriwalla, A. K., S. Vemulapalli, D. R. Holmes, Jr., D. Dai, Z. Li, G. Ailawadi, D. Glower, S. Kar, M. J. Mack, J. Rymer, A. S. Kosinski and P. Sorajja (2019). “Institutional Experience With Transcatheter Mitral Valve Repair and Clinical Outcomes: Insights From the TVT Registry.” JACC Cardiovasc Interv 12(14): 1342-1352.

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OBJECTIVES: The aim of this study was to examine the relation between institutional experience and procedural results of transcatheter mitral valve repair. BACKGROUND: Transcatheter mitral valve repair for the treatment of mitral regurgitation (MR) is a complex procedure requiring navigation of the left atrium, left ventricle, and mitral valve apparatus using echocardiographic guidance. METHODS: MitraClip procedures from the Society of Thoracic Surgeons/American College of Cardiology TVT (Transcatheter Valve Therapy) Registry were stratified into tertiles on the basis of site-specific case sequence (1 to 18, 19 to 51, and 52 to 482). In-hospital outcomes of procedural success, procedural time, and procedural complications were examined. To evaluate the learning curve for the procedure, generalized linear mixed models were developed using case sequence number as a continuous variable. RESULTS: MitraClip procedures (n = 12,334) performed at 275 sites between November 2013 and September 2017 were analyzed. Optimal procedural success (less-than-or-equal-to 1+ residual MR without mortality or need for cardiac surgery) increased across tertiles of case experience (62.0%, 65.5%, and 72.5%; p < 0.001), whereas procedural time and procedural complications decreased. Acceptable procedural success (less-than-or-equal-to2+ residual MR without death or need for cardiac surgery) also increased across tertiles of case experience, but the differences were smaller (91.2%, 91.2%; and 92.9%; p = 0.006). In the learning-curve analysis, visual inflection points for procedural time, procedural success, and procedural complications were evident after about 50 cases, with continued improvements observed up to 200 cases. CONCLUSIONS: For transcatheter mitral valve repair with the MitraClip, increasing institutional experience was associated with improvements in procedural success, procedure time, and procedural complications. The impact of institutional experience was larger when considering the goal of achieving optimal MR reduction.

Makkar, R. R., S. H. Yoon, M. B. Leon, T. Chakravarty, M. Rinaldi, P. B. Shah, E. R. Skipper, V. H. Thourani, V. Babaliaros, W. Cheng, A. Trento, S. Vemulapalli, S. R. Kapadia, S. Kodali, M. J. Mack, G. H. L. Tang and T. Kaneko (2019). “Association Between Transcatheter Aortic Valve Replacement for Bicuspid vs Tricuspid Aortic Stenosis and Mortality or Stroke.” JAMA 321(22): 2193-2202.

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Importance: Transcatheter aortic valve replacement (TAVR) indications are expanding, leading to an increasing number of patients with bicuspid aortic stenosis undergoing TAVR. Pivotal randomized trials conducted to obtain US Food and Drug Administration approval excluded bicuspid anatomy. Objective: To compare the outcomes of TAVR with a balloon-expandable valve for bicuspid vs tricuspid aortic stenosis. Design, Setting, and Participants: Registry-based prospective cohort study of patients undergoing TAVR at 552 US centers. Participants were enrolled in the Society of Thoracic Surgeons (STS)/American College of Cardiology (ACC) Transcatheter Valve Therapies Registry from June 2015 to November 2018. Exposures: TAVR for bicuspid vs tricuspid aortic stenosis. Main Outcomes and Measures: Primary outcomes were 30-day and 1-year mortality and stroke. Secondary outcomes included procedural complications, valve hemodynamics, and quality of life assessment. Results: Of 81822 consecutive patients with aortic stenosis (2726 bicuspid; 79096 tricuspid), 2691 propensity-score matched pairs of bicuspid and tricuspid aortic stenosis were analyzed (median age, 74 years [interquartile range {IQR}, 66-81 years]; 39.1%, women; mean [SD] STS-predicted risk of mortality, 4.9% [4.0%] and 5.1% [4.2%], respectively). All-cause mortality was not significantly different between patients with bicuspid and tricuspid aortic stenosis at 30 days (2.6% vs 2.5%; hazard ratio [HR], 1.04, [95% CI, 0.74-1.47]) and 1 year (10.5% vs 12.0%; HR, 0.90 [95% CI, 0.73-1.10]). The 30-day stroke rate was significantly higher for bicuspid vs tricuspid aortic stenosis (2.5% vs 1.6%; HR, 1.57 [95% CI, 1.06-2.33]). The risk of procedural complications requiring open heart surgery was significantly higher in the bicuspid vs tricuspid cohort (0.9% vs 0.4%, respectively; absolute risk difference [RD], 0.5% [95% CI, 0%-0.9%]). There were no significant differences in valve hemodynamics. There were no significant differences in moderate or severe paravalvular leak at 30 days (2.0% vs 2.4%; absolute RD, 0.3% [95% CI, -1.3% to 0.7%]) and 1 year (3.2% vs 2.5%; absolute RD, 0.7% [95% CI, -1.3% to 2.7%]). At 1 year there was no significant difference in improvement in quality of life between the groups (difference in improvement in the Kansas City Cardiomyopathy Questionnaire overall summary score, -2.4 [95% CI, -5.1 to 0.3]; P = .08). Conclusions and Relevance: In this preliminary, registry-based study of propensity-matched patients who had undergone transcatheter aortic valve replacement for aortic stenosis, patients with bicuspid vs tricuspid aortic stenosis had no significant difference in 30-day or 1-year mortality but had increased 30-day risk for stroke. Because of the potential for selection bias and the absence of a control group treated surgically for bicuspid stenosis, randomized trials are needed to adequately assess the efficacy and safety of transcatheter aortic valve replacement for bicuspid aortic stenosis.

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 380(26): 2541-2550.

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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. (Funded by the American College of Cardiology Foundation National Cardiovascular Data Registry and the Society of Thoracic Surgeons.).

Hamandi, M., R. L. Smith, W. H. Ryan, P. A. Grayburn, A. Vasudevan, T. J. George, J. M. DiMaio, K. A. Hutcheson, W. Brinkman, M. Szerlip, D. O. Moore and M. J. Mack (2019). “Outcomes of Isolated Tricuspid Valve Surgery Have Improved in the Modern Era.” Ann Thorac Surg 108(1): 11-15.

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BACKGROUND: Surgery for isolated tricuspid valve (TV) disease remains relatively infrequent because of significant patient comorbidities and poor surgical outcomes. This study reviewed the experience with isolated TV surgery in the current era to determine whether outcomes have improved. METHODS: From 2007 through 2017, 685 TV operations were performed in a single institution, of which 95 (13.9%) operations were isolated TV surgery. Patients were analyzed for disease origin, risk factors, operative mortality and morbidity, and long-term survival. RESULTS: A total of 95 patients underwent isolated TV surgery, an average of 9 patients per year increasing from an average of 5 per year to 15 per year during the study period. Surgery was reoperative in 41% (38 of 95) of patients, including 11.6% (11 of 95) with prior coronary artery bypass grafting and 29.4% (28 of 95) with prior valve surgery (9 TV, 11 mitral, 2 aortic, 5 mitral and aortic, and 1 mitral and TV). Repair was performed in 71.6% (68 of 95) of patients, and replacement was performed in 28.4% (27 of 95). Operative mortality was 3.2% (3 of 95), with no mortality in the most recent 73 patients over the last 6 years. Stroke occurred in 2.1% (2 of 95) of patients, acute kidney injury requiring dialysis in 5.3% (5 of 95), and the need for new permanent pacemaker in 16.8% (16 of 95). CONCLUSIONS: In the current era with careful patient selection and periprocedural management, isolated TV surgery can be performed with lower morbidity and mortality than has traditionally been reported with good long-term survival. These outcomes can also serve as a benchmark for catheter-based TV intervention outcomes.