In cardiogenic shock, edge-to-edge mitral valve repair improves outcome

In patients with severe mitral regurgitation (MR) and cardiogenic shock, successful transcatheter edge-to-edge repair (TEER) is associated with a significant reduction in all-cause mortality and reduced morbidity at 1 year, according to an analysis of registry data.

The data from this analysis also confirms that “successful reduction in MR in most patients in cardiogenic shock is achievable with TEER,” reported Mohamad A. Alkhouli, MD, an interventional cardiologist and professor of medicine at the Mayo Clinic, Rochester. Minnesota.

In those with successful implantation, which was achieved in 85.6% of patients, all-cause mortality was approximately 21% lower (34.6% vs. 55.5%; P < 0.001) at 1 year than those that were not successfully repaired, according to Dr. Alkhouli, who presented the results at the Transcatheter Cardiovascular Therapeutics Annual Meeting in Boston. This resulted in a nearly 50% reduction in the hazard ratio for death (HR, 0.52; 95% confidence interval, 0.43-0.63).

A similar relative benefit was seen for the composite endpoint of mortality and heart failure admissions at 1 year. Whether unadjusted (HR, 0.54; 95% CI, 0.45-0.66) or adjusted (HR, 0.51; 95% CI, 0.42-0.62), risk reductions with successful MR reduction, defined as ≥1 grade improvement and a final MR grade of ≤2+, indicates serious adverse events are reduced by approximately half.

Requested STS/ACC-TCT registration data

From the Society of Thoracic Surgeons/American College of Cardiology Transcatheter Valve Therapy Registry, 3,797 patients in cardiogenic shock underwent MR repair between November 2013 and December 2021. Results at 1 year were evaluable in 2,773 of these patients. To be included, all had to meet at least one of the definitions of cardiogenic shock, such as: B. inotropic use or mechanical circulatory support.

At baseline, 94.5% had MR grade 3+ or greater, and most of them had grade 4+. Thirty days after treatment, 88.8% had MR grade 2+ or less, most of which had grade 1+.

According to Dr. Alkhouli an important question that has not been well studied so far. Cardiogenic shock is associated with a high risk of death in MR patients, but there is little evidence that valve repair does not exacerbate, let alone modify, this risk.

These data support the value of the intervention, which was performed in almost all patients with MitraClipä (Abbott), the only available device, for most of the time the registry was consulted. dr However, Alkhouli cautioned that his data is best viewed as “hypothesis-generating”.

“We need a randomized trial,” he said at the meeting, which was sponsored by the Cardiovascular Research Foundation. He noted that this is a complex population for which multiple variables could lead to skewed results when the data are analyzed retrospectively. Finally, the MR cardiogenic shock patients in the database considered for TEER may have been relatively healthy and not representative of an unselected population with both MR and cardiogenic shock.

The multi-centre Canadian study CAPITAL MINOS, which has just started, could answer this question better. It was described in an article in the American Heart Journal and has a planned enrollment of approximately 150 MR patients in cardiogenic shock who will be randomized to TEER or medical therapy. According to Dr. Alkhouli expected in about a year.

In relation to the present analysis, Dr. However, Alkhouli notes that sensitivity analyzes performed within his data across risk factors, such as acute coronary syndrome (ACS), consistently supported a benefit of an intervention.

Also, cardiogenic shock does not appear to be a factor in device failure, according to Dr. Alkhouli, addressing a potential criticism that cardiogenic shock was an underlying reason for the device’s failure.

> 90% in NYHA Class III or IV heart failure

In this study, the median age was 73 years. More than 90% had class III or IV heart failure in the 2 weeks prior to TEER. More than half had established coronary artery disease. Other concomitant cardiovascular morbidities, including atrial fibrillation or flutter (65%), prior myocardial infarction (39%), and prior stroke or transient ischemic attack (>10%) were well represented.

When those with device success were compared with those with device failure, the risk profile was comparable. The predicted STS (Society of Thoracic Surgeons) mortality for mitral valve repair in these two groups was 14.8% vs 15% (P = 0.97).

However, patients with device failure had a lower left ventricular ejection fraction (40.7% vs. 42.9%; P = 0.009) and a greater prevalence of moderate to severe or severe MI (96.1% vs. 84.9%; P < 0.001).

The growing experience with TEER means that the benefit has now been demonstrated in several complicated MR groups, such as: B. in patients with severe ventricular dysfunction, renal insufficiency and obstructive pulmonary disease. This was a reason to investigate the impact or repair of MR in patients in cardiogenic shock.

according to dr Alkhouli this is an urgent question. He cited studies suggesting that up to 20% of patients hospitalized for cardiogenic shock have at least moderate to severe MR. Conversely, cardiogenic shock is not an uncommon finding in patients with MR.

while dr Alkhouli acknowledged that the many variables affecting outcome in patients with MR and cardiogenic shock would make a randomized trial “challenging”, many experts shared this concern and even expressed some skepticism about the potential of an unbiased study.

Data confirm that MR repair is safe during shock

“These data demonstrate that MR repair is safe in patients in cardiogenic shock,” said Anita W. Asgar, MD, an interventional cardiologist affiliated with the Montreal Heart Institute, Canada. She noted that in this analysis, there was a 5 to 6 day delay in the patients in cardiogenic shock before undergoing MR repair, possibly indicating elimination of the very high risk patients. Similarly, she suggested that many interventionalists would likely consider several variables before proceeding.

As a result, MR repair may not be amenable to randomization in a cardiogenic shock population because this decision is not usually made outside of the context of multiple variables.

“I’m not sure that a clinical trial is ethical,” she said. She would expect that doctors who admit patients would only do so selectively.

Alexandra J. Lansky, MD, director of the Yale Heart and Vascular Research Program, Yale University, New Haven, Connecticut, also emphasized the difficulty in controlling variables such as cardiogenic shock duration that influence decision making.

Nevertheless, she called the data “very important” as they provide at least some objective data for deciding whether to intervene on a group of “challenging” patients that they often encounter in clinical practice.

dr Alkhouli reports financial relationships with Abbott Vascular, Boston Scientific, Johnson & Johnson and Phillips. dr Asgar reports financial relationships with Abbott Vascular, Edwards Lifesciences, WL Gore & Associates and Medtronic. dr Lasky discloses no potential conflicts of interest.