Usefulness of the Macruz Index for Predicting Successful Percutaneous Mitral Balloon Valvuloplasty in Patients with Mitral Stenosis

OBJECTIVE: The aim of this study was to determine whether the Macruz index (P/P-R segment) could predict the severity of valvular involvement and the success of percutaneous mitral balloon valvuloplasty (PMBV) in patients with mitral stenosis (MS). SUBJECTS AND METHODS: Sixty-one patients with MS eligible for PMBV and 72 healthy subjects (61 females and 11 males) with sinus rhythm were enrolled into this study. PMBV was performed in all patients using a percutaneous transseptal antegrade approach and a multitrack balloon technique. The P/P-R segment ratio and echocardiographic variables were measured before and 48-72 h after the procedure. The optimal cutoff point for differences in the Macruz index to determine clinical success was evaluated by receiver operating characteristic analysis by calculating the area under the curve as giving the maximum sum of sensitivity and specificity for the significant test. RESULTS: In the patient group (mean age 42.9 ± 11.1 years), the preprocedural Macruz index was significantly higher than in the control group (2.79 ± 1.03 vs. 1.29 ± 0.11; p < 0.001). In the successful-procedure group (n = 53), the mean postindex value was significantly lower (2.12 ± 0.71 vs. 2.81 ± 1.0, p = 0.020), and the decrease in the Macruz index was significantly higher than in the unsuccessful-procedure group (p = 0.007). An index decrease of 0.105 was the best cutoff value to distinguish the successful-PMBV group from the unsuccessful- PMBV group (area under the curve = 0.888, 95% confidence interval 0.788-0.988, p < 0.001). CONCLUSION: The Macruz index was significantly higher in patients with MS compared to healthy subjects. A greater decrease in the Macruz index was associated with a successful PMBV.