However, the findings come from an observational study, the authors note, and “prospective randomized trials are required to confirm the efficacy of early PMC.”
Dr. Duk-Hyun Kang and colleagues with the College of Medicine, University of Ulsan, Seoul, explain that percutaneous commissurotomy for moderate asymptomatic mitral stenosis is controversial. They hypothesized that early intervention compared to conventional treatment would improve outcomes.
To investigate, the team conducted a prospective study of 244 patients with moderate rheumatic mitral stenosis enrolled over a 10-year period. Based on the treating physicians’ discretion and the patients’ preferences, 138 patients underwent percutaneous mitral commissurotomy while 106 received conventional treatment.
In the PMC group, the procedure was successful in 97%. There were no procedure-related deaths and none of the patients required urgent surgery.
The authors defined the primary endpoint as a composite of cardiovascular mortality, cerebral infarction, systemic embolic events, and PMC-related complications. Estimated actuarial 11-year event-free survival rates were 89% in the PMC arm compared with 69% in the conventional arm (p<0.001), they report.
“To reduce the effect of treatment selection bias and potential confounding in this observational study,” the investigators explain, “we performed rigorous adjustment for the differences in baseline characteristics using propensity score matching.”
That yielded 62 matched pairs. In this subset, the actuarial event-free survival rates in the two groups were 87% vs 75%, respectively (p=0.024), the data indicate.
With regard to embolic events per se, the 11-year actuarial rates were 7% in the PMC group and 23% among those receiving conventional treatment, the researchers found.
“Early PMC in asymptomatic patients with moderate MS (mitral stenosis) was associated with better long-term event-free survival owing to a more effective decrease in the incidence of embolic events,” Dr. Kang and colleagues write.
They conclude, “Early intervention may be a valuable therapeutic option to further improve clinical outcomes in these asymptomatic MS patient.”