Higher operator volume confers better outcomes after mitral valve surgery

In patients undergoing mitral valve surgery, operator volume was associated with durable repair and survival at 1 year, according to a presentation at the American Association for Thoracic Surgery Week.

“There is now a fair amount of medical literature supporting the case that high volumes generally lead to better surgical outcomes, in a wide variety of fields,” Joanna Chikwe, MD, clinical professor for cardiovascular surgery at the Icahn School of Medicine at Mount Sinai, said in a press release. “This study shows that for patients undergoing mitral surgery, both immediate and subsequent outcomes were influenced by the individual surgeon’s experience.”

Researchers used a mandatory state of New York database consisting of 5,475 patients with degenerative disease who underwent mitral surgery between 2002 and 2013 to assess the link between degenerative mitral repair rates and outcomes and a surgeon’s case volume.

Patients included in the study were aged 18 years or older and were identified using the Statewide Planning and Research Cooperative System database.

Endpoints for the study were all-cause mortality, degenerative repair rates and postrepair mitral valve reoperation, which was defined as any mitral valve surgery, all at 1 year.

Median annual operator volume was 10 procedures (range, 1-230) and the mean repair rate was 55% (20,797 of 38,128). The findings were simultaneously published in the Journal of the American College of Cardiology.

In the degenerative cohort, researchers found an association between lower total annual surgeon volume and lower mitral valve repair rates. The mean mitral valve repair rate in this cohort was 67% and had a range of 0% to 100%.

Mean repair rates were 48% (179 of 370) for surgeons with total annual volumes of 10 or fewer mitral operations and 77% (1,710 of 2,216) for surgeons with total annual volumes of more than 50 mitral operations (P < .001).

Higher operator volume was independently associated with increased rates of degenerative mitral repair (adjusted OR = 1.13 per each 10 additional cases; 95% CI, 1.1-1.17), decreased risk for reoperation until 25 annual cases and improved rate of survival at 1 year (adjusted HR = 0.95 per each 10 additional cases; 95% CI, 0.92-0.98), according to Chikwe and colleagues.

Repair rates were higher (63.8%) for surgeons with a total annual volume 25 mitral operations or less, if they operated in the same institution as a surgeon with total annual mitral volumes of at least 50 and degenerative mitral valve repair rates of at least 70%, compared with those operating in other institutions (51.3%; adjusted OR = 1.79; 95% CI, 1.24-2.6).

“Analyzing a mandatory New York State database, Chikwe et al evaluated the impact of surgeon case volume on degenerative mitral valve repair rates and surgical outcomes,” Marc Gillinov, MD, from the department of thoracic and cardiovascular surgery at Cleveland Clinic, and colleagues wrote in a related editorial published in JACC. “Their findings come as no surprise; surgeons who perform more mitral valve operations have higher repair rates, and their patients face reduced risks of death and mitral valve reoperation. Practice does not make perfect, but for most surgeons, practice certainly makes better.” – by Dave Quaile

References:

Chikwe J, et al. Plenary Scientific Session. Presented at: AATS Week 2017; April 29-May 3, 2017; Boston.

Chikwe J, et al. J Am Coll Cardiol. 2017;doi:10.1016/j.jacc.2017.02.026.

Gillinov M, et al. J Am Coll Cardiol. 2017;doi:10.1016/j.jacc.2017.01.059.

Disclosure: Chikwe reports receiving honoraria from Edwards Lifesciences. Gillinov reports consulting for Abbott, CryoLife, Edwards Lifesciences, Medtronic and St. Jude Medical and receiving research support from St. Jude Medical and Tendyne.