Edge-to-edge valve repair may improve mortality in severe MR, cardiogenic shock
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BOSTON — In a large registry analysis, transcatheter edge-to-edge mitral valve repair had a high rate of device success in patients with severe mitral regurgitation and cardiogenic shock.
In addition, compared with device failure, device success with the mitral valve repair system (MitraClip, Abbott) was associated with reduced risk for all-cause mortality at 1 year.
Approximately 88.2% of patients achieved a final mitral regurgitation (MR) grade of less than 2+, according to data presented at TCT 2022 and simultaneously published in the Journal of the American College of Cardiology.
“Cariogenic shock remains associated with significant morbidity and mortality and not many interventions have shown benefit in this population. We've also seen that the comorbidities of those patients are changing. More patients are presenting with nonacute MI and cardiogenic shock and significant valve disease,” Mohamad Alkhouli, MD, interventional cardiologist and professor of medicine in the department of cardiovascular medicine at Mayo Clinic, said during a press conference. “Indeed, up to 20% of patients with cardiogenic shock have significant mitral regurgitation and we know that mitral regurgitation does increase mortality in these patients. What we don't know is whether intervening in the mitral regurgitation helps.”
Researchers utilized the collaborative Society of Thoracic Surgeons/American College of Cardiology Transcatheter Valve Therapy registry to better understand the outcomes of transcatheter edge-to-edge mitral valve repair in patients with severe MR and concomitant cardiogenic shock.
Device success was defined as MR grade reduction of 1 or more and a final grade of 2+ or less.
The primary outcomes were mortality and mortality or HF hospitalization at 1 year.
Alkhouli and colleagues included a total of 3,797 patients (mean age, 73 years; 60% men; 53.4% with degenerative MR). In this cohort, the average STS Predicted Risk of Mortality score was 14.9%.
Transcatheter edge-to-edge repair success was achieved in 85.6% of patients with severe MR and cardiogenic shock, of which a final MR grade of less than 2+ was achieved in 88.2% and reduction of 1 grade or more was achieved in 91.4%, according to the researchers.
Compared with device failure, successful transcatheter edge-to-edge mitral valve repair was associated with decreased all-cause mortality (34.6% vs. 55.5%; adjusted HR = 0.49; 95% CI, 0.41-0.59; P < .001) and a composite of all-cause mortality or HF hospitalization (29.6% vs. 45.2%; aHR = 0.51; 95% CI, 0.42-0.62; P < .001), Alkhouli said at the press conference.
The number needed to treat to prevent one death at 1 year was 4.8, while the number needed to treat to prevent one death or HF hospitalization at 1 year was 6.4, according to the researchers.
Researchers conducted interaction testing to assess whether their definition of cardiogenic shock, MR etiology, left ventricular ejection fraction or presence of ACS at presentation might have impacted device success, and no significant interaction was observed.
“In this large database of patients who underwent a MitraClip procedure and had cardiogenic shock ... device success was achieved in 85% of patients and was associated with significantly lower mortality and fewer heart failure hospitalizations at 1 year. For mortality, the number needed to treat was only five,” Alkhouli said during the press conference. “Given the limitations of observational or prospective data, we should view this as hypothesis-generating. We still need a randomized trial to clarify the role of TEER. We know that's a difficult trial to do, but fortunately there is a multicenter clinical trial called CAPITAL MINUS that has already started to enroll patients to address this question.”
Reference:
Perspective
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This study showed 1) that in a large registry study of patients with cardiogenic shock and severe mitral regurgitation, a decrease in MR by transcatheter edge-to-edge repair (TEER) was successful in a majority of patients (86%) and 2) that patients who did have their MR reduced by TEER, had better outcomes in terms of mortality and HF admissions at 1 year.
The potential impact is important in that patients with cardiogenic shock and MR are critically ill with limited options, so TEER in this group provides another potential therapeutic option.
This was a registry study, which means it is subject to selection bias, so I would like to see confirmation of these results.
I commend the authors for doing this study. Patients with cardiogenic shock are a critically ill group with overall poor prognosis, so it is an important group to study to improve our care for them.
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Neal S. Kleiman, MD, MSCAI, FACC
The most important take-home message is that the procedure can be done successfully with a reasonable degree of safety in a really sick population. The observation means that if there is a patient with florid shock whose ventricle is not completely shot and has a flailing mitral leaflet, we can clip it.
The study was nonrandomized and therefore has all sorts of biases, but knowing that the procedure can be done successfully with a pretty good safety margin, considering the population, is encouraging. Comparing device success vs. failure can be a slippery slope, since often, the difference is due to patient characteristics as opposed to the treatment.
The fact that the procedure can be done, the success rate is high and the safety margin is good, provided the ventricle has not suffered too severe an insult, means it will be hard not to recommend a clip in this population, despite the study not having a control group.
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Alkhouli M, et al. Late-Breaking Clinical Science in Structural Heart Disease: Session I, in Collaboration With The New England Journal of Medicine. Presented at: TCT Scientific Symposium; Sept. 16-19, 2022; Boston (hybrid meeting).
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