The overall case volume for surgical mitral-valve (MV) repair of degenerative mitral regurgitation (DMR) hasn't changed much nearly a decade into the age of transcatheter edge-to-edge repair (TEER). But, over the same period, there's been a shift in the surgical MV repair case mix at centers that have offered both the surgical option and TEER, a new study suggests.
Once TEER was introduced, those centers over time used the operative approach less in higher and intermediate surgical risk patients and more often in those deemed low risk for surgery. And that trend — at centers offering both approaches — paralleled improved risk-adjusted surgical repair short-term complications and 30-day and 5-year mortality.
The findings come from an analysis based on Society of Thoracic Surgeons (STS) and Medicare claims data collected from 2011 through 2018 at surgical MV-repair centers that also offered TEER for DMR after its 2013 approval. The transcatheter procedure, until only recently the exclusive domain of Abbott's MitraClip in various incarnations, is officially indicated for patients judged too high-risk for surgical MV repair.
A shift in surgical MV repair to predominantly lower-risk patients would be expected to improve outcomes. But the improvements seen in the current study seem to have a more complex explanation, Sreekanth Vemulapalli, MD, told theheart.org | Medscape Cardiology.
The data seem to show TEER indication-creep from higher-risk cases, for which there is clinical trial support, to intermediate-risk patients, that lack such evidence in favor of TEER. That seemed to push surgical repair toward even lower-risk cases. "I think that's exactly right," said Vemulapalli, Duke Clinical Research Institute (DCRI), Durham, North Carolina.
Still, he observed, the analysis was adjusted for surgical risk, and "Even after that adjustment, it looked like surgical outcomes were getting better after the availability of transcatheter mitral repair techniques."
That observation may be explained by an increasingly sharp, "more careful" process for selecting patients for surgical repair vs TEER, said Vemulapalli, who is senior author on the study's publication February 6 in the Journal of the American College of Cardiology. Angela M. Lowenstern, MD, Vanderbilt University, Nashville, and Andrew M. Vekstein, MD, DCRI, were the lead authors.
Indeed, the report states, the analysis supports the view that "a systematic evaluation by a heart team able to direct patients towards either surgical or transcatheter approaches enhances both short-term and long-term surgical outcomes."
"In a world where both surgical and transcatheter techniques are going to be available," Vemulapalli said, "patient selection becomes very, very important."
An accompanying editorial acknowledges the heart-team approach's potential for improving the selection of patients for surgery and perhaps therefore outcomes. But it also cites issues with that interpretation of the data.
For example, the heart-team approach is not used in consistent ways across the United States. And "although the heart team is recommended in multiple guidelines for valvular heart therapies, there is little evidence for its efficacy, specifically regarding improving clinical outcomes," write Matthew W. Sherwood, MD, MHS, and Wayne B. Batchelor, MD, MHS, Inova Heart and Vascular Institute, Falls Church, Virginia.
The editorialists highlight the study's "significant downtrend in both high-risk and intermediate-risk surgical cases, with a concomitant increase in low-risk cases," after introduction of TEER. That shift in case mix, they write, "would seem to be a more likely explanation for the modest improvement in outcomes for surgical MV repair."
Also, importantly, the analysis didn't include data on TEER procedures, only indirect evidence for TEER's effect on surgical MV repair, the editorialists observe, and study authors acknowledge.
Still, the analysis looked at nearly 14,000 patients at 278 US sites with surgical MV repair that launched TEER programs during the study period. They accounted for 6806 surgical cases before and 7153 surgical cases after the advent of TEER.
Their median annualized institutional surgical MV repair volume was 32 before and 29 after TEER availability (P = .06).
The risk-adjusted odds ratio (OR) for 30-day mortality after vs before TEER became an option was 0.73 (95% confidence interval [CI], 0.54 - 0.99). The corresponding hazard ratio for mortality at 5 years was 0.75 (95% CI, 0.66 - 0.86).
Other risk-adjusted surgical outcomes improved once TEER became available, including:
MV adverse outcomes, OR 0.71 (95% CI, 0.58 - 0.86; P < .001)
Operative mortality, OR 0.73 (95% CI, 0.54 - 0.99; P = .041)
Major morbidity, OR 0.85 (95% CI, 0.73 - 0.98; P = .026)
Despite the data's suggestion of TEER indication-creep from solely high-surgical-risk patients to those at intermediate risk, Vemulapalli said, "I don't think that people should be doing transcatheter mitral repair in intermediate or low-risk patients as a general rule." Although, he added, "there will always be certain exceptions, depending on the patient's specific situation."
Vemulapalli pointed to several ongoing trials comparing TEER vs surgical MR repair in patients with DMR at intermediate surgical risk, including REPAIR MR and PRIMARY.
J Am Coll Cardiol, 2023. Published online February 6. Abstract, Editorial
The study was supported by the National Institutes of Health and Abbott. Vemulapalli discloses receiving grants or contracts from the American College of Cardiology, the Society of Thoracic Surgeons, Cytokinetics, Abbott Vascular, the National Institutes of Health, and Boston Scientific; and consulting or serving on an advisory board for Janssen, the American College of Physicians, HeartFlow, and Edwards LifeSciences. Disclosures for the other authors are in the report. Sherwood discloses receiving honoraria or consulting fees from Medtronic and Boston Scientific. Batchelor discloses receiving consulting fees from Medtronic, Boston Scientific, Edwards Lifesciences, and Abbott.
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Cite this: What Happened to Surgical Mitral Valve Repair in the MitraClip Era? - Medscape - Feb 08, 2023.