Michael J. Mack M.D.

Baumgarten, H., J. J. Squiers, W. T. Brinkman, J. M. DiMaio, A. Gopal, M. J. Mack and R. L. Smith (2016). “Implantation of transcatheter aortic prosthesis in 3 patients with mitral annular calcification.” Ann Thorac Surg 102(5): e433-e435.

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Mitral annular calcification (MAC) is a chronic degenerative process at the fibrous base of the mitral valve. It is a feared diagnosis in the context of mitral valve operations because of the risk of severe adverse events such as atrioventricular disruption, injury to the circumflex artery during debridement, and difficult placement of annular sutures. We report a series of 3 consecutive female patients with severe circular MAC who underwent successful mitral valve replacement through a lateral minithoracotomy with use of an inverted transcatheter aortic valve.

Mack, M. and D. Holmes (2016). “Bioprosthetic valve thrombosis: The harder one looks, the more one finds.” J Thorac Cardiovasc Surg 152(4): 952-953.

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The desire to avoid anticoagulation after surgical aortic valve replacement (SAVR) has been one of the major drivers toward the greater use of bioprosthetic valves and less use of mechanical valves so that more than 90% of surgical valves now implanted are tissue. Recently concerns have been raised about the occurrence of bioprosthetic valve thrombosis (BPVT) and its possible relationship to subsequent structural valve deterioration.1 Recent studies done with sophisticated imaging techniques, including 4-dimensional computed tomography (4D CT) with high-speed scanners have clearly documented leaflet immobility, thickness, and thrombosis both early and late after both SAVR and transcatheter aortic valve replacement (TAVR) procedures (Figure 1).2 Although the true incidence and clinical relevance of these different findings are as yet unknown, it is clear that the phenomenon is more common than was previously appreciated.3

Thourani, V. H., J. Forcillo, N. Beohar, D. Doshi, R. Parvataneni, G. M. Ayele, A. J. Kirtane, V. Babaliaros, S. Kodali, C. Devireddy, W. Szeto, H. C. Herrmann, R. Makkar, G. Ailawadi, S. Lim, H. S. Maniar, A. Zajarias, R. Suri, E. M. Tuzcu, S. Kapadia, L. Svensson, J. Condado, H. A. Jensen, M. J. Mack and M. B. Leon (2016). “Impact of preoperative chronic kidney disease in 2,531 high-risk and inoperable patients undergoing transcatheter aortic valve replacement in the partner trial.” Ann Thorac Surg 102(4): 1172-1180.

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BACKGROUND: Although preoperative renal dysfunction (RD) is associated with increased mortality and morbidity after surgical aortic valve replacement, its impact on clinical outcomes after transcatheter aortic valve replacement (TAVR) is less defined. METHODS: TAVR patients in the PARTNER (Placement of Aortic Transcatheter Valves) trial with a calculable glomerular filtration rate (GFR) using the Modification of Diet in Renal Disease equation were included. Patients were divided into three groups: GFR >60 mL/min (none/mild RD), GFR 31 to 60 mL/min (moderate RD), and GFR

Suri, R. M., S. Minha, O. Alli, R. Waksman, C. S. Rihal, L. P. Satler, K. L. Greason, R. Torguson, A. D. Pichard, M. Mack, L. G. Svensson, J. Rajeswaran, A. M. Lowry, J. Ehrlinger, S. L. Mick, E. M. Tuzcu, V. H. Thourani, R. Makkar, D. Holmes, M. B. Leon and E. H. Blackstone (2016). “Learning curves for transapical transcatheter aortic valve replacement in the partner-i trial: Technical performance, success, and safety.” J Thorac Cardiovasc Surg 152(3): 773-780.

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OBJECTIVES: Introduction of hybrid techniques, such as transapical transcatheter aortic valve replacement (TA-TAVR), requires skills that a heart team must master to achieve technical efficiency: the technical performance learning curve. To date, the learning curve for TA-TAVR remains unknown. We therefore evaluated the rate at which technical performance improved, assessed change in occurrence of adverse events in relation to technical performance, and determined whether adverse events after TA-TAVR were linked to acquiring technical performance efficiency (the learning curve). METHODS: From April 2007 to February 2012, 1100 patients, average age 85.0 +/- 6.4 years, underwent TA-TAVR in the PARTNER-I trial. Learning curves were defined by institution-specific patient sequence number using nonlinear mixed modeling. RESULTS: Mean procedure time decreased from 131 to 116 minutes within 30 cases (P = .06) and device success increased to 90% by case 45 (P = .0007). Within 30 days, 354 patients experienced a major adverse event (stroke in 29, death in 96), with possibly decreased complications over time (P approximately .08). Although longer procedure time was associated with more adverse events (P < .0001), these events were associated with change in patient risk profile, not the technical performance learning curve (P = .8). CONCLUSIONS: The learning curve for TA-TAVR was 30 to 45 procedures performed, and technical efficiency was achieved without compromising patient safety. Although fewer patients are now undergoing TAVR via nontransfemoral access, understanding TA-TAVR learning curves and their relationship with outcomes is important as the field moves toward next-generation devices, such as those to replace the mitral valve, delivered via the left ventricular apex.

Messe, S. R. and M. J. Mack (2016). “Improving outcomes from transcatheter aortic valve implantation: Protecting the brain from the heart.” Jama 316(6): 587-588.

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In this issue of JAMA, Haussig and colleagues6 report the results of the CLEAN-TAVI study. This randomized clinical trial assessed the utility of an embolic protection device (the CLARET Montage Dual Filter System) designed for use in transcatheter aortic valve implantation (TAVI). Once deployed through the right brachial artery, this device uses 2 filters to cover 3 of the 4 cervicocephalic vessels, including both carotid arteries and the right vertebral artery, while the left vertebral artery remains unprotected. A total of 100 patients with severe aortic stenosis were randomized to undergo TAVI with (n = 50) or without (n = 50) the cerebral embolic protection device; the device was successfully placed in 92% of patients in the intervention group, with no device-related complications reported. The primary end point was the numerical difference in new postprocedure lesions in potentially protected brain territories detected on MRI at 2 days following TAVI.