By Jeffrey Zimmet, MD, PhD
Associate Professor of Medicine, University of California, San Francisco; Director, Cardiac Catheterization Laboratory, San Francisco VA Medical Center
SYNOPSIS: The authors of this large registry study examined transcatheter edge-to-edge repair in patients with cardiogenic shock and severe mitral regurgitation (MR). Successful repair was achievable in most patients and was associated with lower mortality rates and heart failure hospitalization at one year.
SOURCE: Simard T, Vemulapalli S, Jurg RG, et al. Transcatheter edge-to-edge mitral valve repair in patients with severe mitral regurgitation and cardiogenic shock. J Am Coll Cardiol 2022;80:2072-2084.
Mitral transcatheter edge-to-edge repair (TEER) is approved in the United States to treat symptomatic degenerative mitral regurgitation (MR), and for functional MR in patients with chronic heart failure with reduced ejection fraction (HFrEF) on optimized medical therapy. As with many device-based therapies, practice often happens well in front of the evidence, especially when treating conditions with high mortality rates and limited therapeutic options. The same is true for cardiogenic shock (CS), for which mortality rates remains elevated despite advances in cardiovascular therapeutics. The numbers of patients with both CS and severe MR are unknown.
Simard et al used the Transcatheter Valve Therapy Registry to identify patients with severe MR and CS who underwent TEER in the United States between Nov. 22, 2013, and Dec. 31, 2021. CS is a variable in the registry; patients who were on inotropes and/or on mechanical circulatory support before the procedure also were included.
During the study period, 3,797 patients undergoing TEER procedures met at least one of the prespecified inclusion criteria for CS. The primary analysis compared outcomes between patients who experienced device success (defined as reduction in MR severity by at least one grade, to a final severity of moderate or less) to those who underwent the procedure but did not achieve defined reductions in MR. The mean age of included patients was 73 years, 59.5% were male, and the average Society of Thoracic Surgeons predicted score for mitral repair surgery was 14.9%. The etiology of MR was marked as degenerative in 53.4%, functional in 27.5%, and mixed in 13.6%.
Of the initial cohort who underwent TEER, 3,249 patients experienced results that met the definition of device success. Patients who underwent successful TEER procedures recorded shorter hospital stays and lower 30-day mortality rates compared with patients who did not (8.8% vs. 21.5% and 12.6% vs. 30.1%, respectively; P < 0.001). At one year, the all-cause mortality rate was significantly lower among patients who experienced protocol-defined device success compared with those who did not (34.6% vs. 55.5%; adjusted HR, 0.49; 95% CI, 0.41-0.59; P < 0.001). A composite of mortality and heart failure admissions also favored patients who underwent successful TEER. The authors concluded successful TEER is feasible in most patients with CS and significant MR and is associated with lower risks of death and congestive HF hospitalization at 12 months.
COMMENTARY
Mitral TEER plays an established role in treating severe symptomatic mitral valve regurgitation in degenerative MR and in a subset of patients with HFrEF. The Simard et al study offers hope for application of mitral TEER in CS patients, although with several caveats. First, determining the presence of CS itself relies on registry data. The Simard et al study certainly was inclusive, capturing patients with inotrope requirements and the use of mechanical circulatory support, but the severity as well as the etiology of CS is difficult to judge.
The rate of study-defined procedural success was quite high, at more than 85%, which is remarkable despite the site-reported (rather than core lab-verified) nature of this metric. The reported reductions in mortality rates and HF hospitalizations here are not comparing TEER with no TEER in these patients. Rather, patients who experienced TEER success were compared with those who underwent the TEER procedure, but experienced suboptimal results. As the authors noted, suboptimal TEER results in the comparator group may simply indicate the presence of other markers of poor outcomes, such as worse left ventricle function and geometry, or more severe mitral valve disease. The suggestion of a substantial benefit of this procedure is something that will need to be verified in ongoing clinical trials.
The authors of this large registry study examined transcatheter edge-to-edge repair in patients with cardiogenic shock and severe mitral regurgitation (MR). Successful repair was achievable in most patients and was associated with lower mortality rates and heart failure hospitalization at one year.
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