Late (up to 12 Years) Clinical and Echocardiographic Outcomes of Percutaneous Transvenous Mitral Commissurotomy in Patients With Rheumatic Mitral Stenosis: Continuing Secondary Antibiotic Prophylaxis Does Not Protect Against Late Events

This research was designed as single-technique (Inoue balloon), multicenter retrospective- prospective cohort study. The target group of this study consisted of 220 patients with symptomatic MS who had undergone PTMC at in 4 hospitals (Baqiyatallah, Namazi, Shahid-Faghihi and Kowsar) under the supervision of Baqiyatallah University of Medical Sciences and Shiraz University of Medical Sciences between April 2006 and January 2018. The demographic data of the patients were obtained from the medical records departments at each center.

The inclusion criteria for the participants were: 1) age more than 20 years at the time of PTMC; 2) immediate post-PTMC mitral valve area (IMVA) ≥1.5 cm2, or for lower values, at least 50% increase in pre-PTMC mitral valve area (MVA); 3) an initial cardiovascular event-free period of at least 6 months after the procedure.

The exclusion criteria consisted of: 1) more than 2+ mitral regurgitation (MR) immediately after the procedure; 2) immediate cardiovascular event during the hospital stay after the procedure; 3) more than mild aortic stenosis or sufficiency before PTMC; 4) history of previous PTMC or surgical mitral procedures.

The study design and steps were approved by the ethics committees at both Baqiyatallah and Shiraz University of Medical Sciences.

PTMC Technique All PTMC procedures were done with an Inoue balloon catheter by skilled interventional cardiologists via anterograde trans-septal approach in all patients. Right and left cardiac catheterization was performed before and during the procedure to assess hemodynamic changes. Optimal balloon size (in millimeters) was estimated with the height (cm)/10 + 10 formula. The balloon was inflated in a step-wise fashion from lower to higher volumes. After each inflation, changes in trans-mitral mean pressure gradient (TMPG) and the degree of mitral regurgitation (MR) were monitored. Based on interventionist's judgement and in order to achieve optimal results, balloon inflation could be continued up to 1-2 mm more than the estimated size. In the last stage, left ventriculography was conducted to assess the degree of final MR.