Benefit seen within a year after edge-to-edge repair

Within one year after edge-to-edge transcatheter mitral valve repair (TMVr), elderly patients with mitral regurgitation had significant and sustained reductions in both all-cause and heart failure (HF) hospitalizations compared with the year prior to undergoing the procedure, according to results from a recent population-based study from Canadian researchers. Pre-procedural hospitalizations were highest in the 30 days before the procedure, while the lowest rates were seen beginning 6 months after the procedure.

Results are published in the Journal of the American College of Cardiology.

“We did this study to better understand the relationship between TMVr and hospitalizations. Due to conflicting published data in selected populations, it was not clear to us what impact TMVr would have in a real-world population that included patients with both degenerative and functional mitral regurgitation,” first author Andrew Czarnecki, MD, MSc, of ICES, Sunnybrook Health Sciences Centre, and the University of Toronto, Ontario, Canada, told BreakingMED.

Using the ICES and CorHealth Cardiac Registry databases, Czarnecki and colleagues identified all patients undergoing TMVr in Ontario, Canada, between 2011 and 2017. The cohort consisted of 523 patients (mean age: 78 years; 39.8% female; 40% medium income) , in whom they assessed hospitalization person-year (PY) rates in the years before and after TMV4 and at four predefined intervals: at 1-30 days, 31 to 90 days, 91 to 182 days, and 183 to 365 days.

Over half of patients (54.5%) were NYHA functional class III, and 21.2% were NYHA functional class II. Left ventricular ejection fraction was 50% or greater in 40.3%, and less than 20% in only 7.1%. A full 69.4% of these patients had undergone cardiac catheterization within the year before TMVr and 13.2% had percutaneous coronary intervention within the preceding year; 13.6% had an implantable cardioverter-defibrillator, and 21.4% had undergone coronary artery bypass graft surgery. The most common patient comorbidities included heart failure (84.5%), atrial fibrillation (69.0%), frailty (39.6%), and myocardial infarction (38.4%).

Upon applying Poisson regression models to compare incidence rates of all-cause and heart failure (HF) hospitalizations, Czarnecki and colleagues found that all-cause hospitalizations during the year preceding TMVr were significantly higher compared with those in the year following the procedure (66.2% vs 47.4%, respectively). The mortality rate was 2.1% at 30-days and 14.7% at one year.

In the periods before TMVr, there were stepwise increases in both all-cause and HF hospitalization rates, while during postprocedural timepoints, they were significantly lower.

At 365 to 183 days preprocedure, for example, the all-cause hospitalization rate was 104/100 person-years (PY), and this increased to 319/100 PY in the 30 days preprocedure. Researchers noted that this was the highest hospitalization rate during the study period.

Then, at 30 days after hospital discharge, these rates decreased to 190/100 PY and continued to decrease to 72/100 PY at 183 to 365 days postprocedure. Researchers also noted that this was the lowest hospitalization rate during the study.

Czarnecki and colleagues also observed similar—but even larger—reductions in HF hospitalizations post-TMVr, with greater than 50% reductions occurring during all study periods. The lowest HF hospitalization rate was seen in the 183 to 365 days after the procedure (14/100 PY).

The adjusted rate ratio (aRR) for all-cause hospitalization in the year after TMVr was 0.65 (95% CI: 0.56-0.76; P˂0.001) and for HF-related hospitalization, 0.38 (95% CI: 0.29-0.51; P˂0.001); at 1-30 days, these aRRs were 0.59 and 0.41, respectively; at 31-90 days, 0.53 and 0.33; at 91-182 days, 0.67 and 0.36; and at 183-365 days, 0.73 and 0.40.

In pre- versus post-procedure comparisons in patients with left ventricular systolic dysfunction, the relative risk for all-cause and HF hospitalization were 0.63 (95% CI: 0.50-0.79; P˂0.001), and 0.35 (95% CI: 0.23-0.53; P˂0.001), respectively.

Median length of hospital stay for the procedure was 3 days. The most common complications were minor bleeding (8.2%), acute kidney injury (3.6%), and major bleeding (2.5%). Within one year of the index TMVr procedure, 1.3% of patients underwent mitral valve replacement.

“The key message here is that TMVr plays an important role in reducing hospitalizations in this high-risk population. Since avoiding hospital admissions is central to improving patient QOL and to reducing healthcare costs, these results should have broad-based impact,” noted Czarnecki in an email correspondence.

“I think the major surprise here was that, not only did TMVr reduce heart failure hospitalizations, but it also reduced all-cause hospitalizations. This was in contrast to previous findings from the TVT Registry. Moreover, the extent to which these reductions were observed was quite impressive–35% reduction in the rate of all-cause and 62% reduction in HF-hospitalizations,” he added.

“We need more data to better understand these relationships. For example, given the clear step-wise rise in hospitalizations leading up to TMVr, it begs the question whether these admissions could be avoided with early intervention or whether these admissions are the trigger for intervention – more study is needed to answer these questions. What is clear, is that we can now tell patients that they are far less likely to be hospitalized after the procedure and this is an important end-point,” Czarnecki concluded.

In an accompanying editorial comment, Daniel Kalbacher, MD, of University Medical Center Hamburg-Eppendorf, Hamburg, and Niklas Schofer, MD, of The German Center for Cardiovascular Research, Lübeck, both in Germany, commended Czarnecki et al on their study.

“By in-depth analysis of specific time periods, the authors could demonstrate a stepwise rise in hospitalization rates in the year preceding TEER and lowest hospitalization rates in the period 6 months after intervention,” they wrote. “The authors have to be congratulated on this important and well-conducted analysis. A major strength of the study is that public health care data could be used, providing complete follow-up information on all study subjects,” they added.

But, they continued, several limitations should be considered, including the difficulty in verifying rehospitalizations for heart failure outside of prospective trials, the lack of data on the etiology and severity of patients’ mitral regurgitation and success rates and the presence of residual mitral regurgitation postprocedure, and newer technological advances of TEER devices and increased operator experience that have occurred since the study was performed.

Other study limitations, according to Czarnecki et al, included the inability to identify a suitable control group, and the exclusion of patients with aborted procedures.

  1. In this population-based study, significant reductions were observed in both all-cause and HF-related hospitalizations in all time periods after TMVr compared with the year prior.

  2. Pre-procedural hospitalizations were highest in the 30 days before the procedure, while the lowest rates were seen beginning 6 months after the procedure.

Liz Meszaros, Deputy Managing Editor, BreakingMED™

This study was supported by the Heart & Stroke Foundation/University of Toronto Polo Chair in Cardiology Young Investigator Award and a foundation grant from the Canadian Institutes of Health Research. This study was supported by ICES, which is funded by an annual grant from the MOHLTC. The authors acknowledge that the clinical registry data used in this publication is from participating hospitals through CorHealth Ontario, which serves as an advisory body to the MOHLTC, is funded by the MOHLTC.

Czarnecki has received speaking honoraria from Abbott Vascular.

Kalbacher has received lecture fees from Edwards Lifesciences and Abbott Medical; and has proctor fees from Edwards Lifesciences.

Schofer has reported that he has no relationships relevant to the contents of this paper to disclose.

Cat ID: 308

Topic ID: 74,308,730,308,914,192,925