Background: Pulmonary hypertension (PH) often complicates mitral stenosis (MS). The prognostic impact of pulmonary vascular resistance (PVR) in MS patients remains unclear. Previous study has demonstrated the prognostic impact of right atrial pressure (RAP) in patients with primary PH. We aim to determine the prognostic impact of PVR and RAP in patients with rheumatic MS undergoing percutaneous mitral balloon valvuloplasty (PMBV). Methods: A total of 58 patients with symptomatic severe rheumatic MS who underwent PMBV between 2016 and 2020 were included. Patients were divided into two groups: PVR ≤ 2WU (N = 26) and PVR > 2WU (N = 32). The composite endpoint included death, reintervention or persistent NYHA functional class III-IV during follow-up. Results: The median age was 50 (42–60) years, with 82.8% being female. Median pulmonary artery systolic pressure (PASP) was 42 (35–50.5) mmHg. Patients with PVR ≤ 2WU had lower PASP on both echocardiogram and catheterization. The PMBV success rate was 75.9%. Multivariate analysis, adjusted for PVR, showed RAP as the only independent predictor of the composite endpoint (HR:1.507, 95% CI:1.015–2.237, p = 0.042). The optimal RAP cutoff was 9.5 mmHg (HR:3.481, 95% CI:1.041–11.641; p = 0.043). Conclusions: RAP was an independent predictor of adverse outcomes in patients with rheumatic MS undergoing PMBV, while PVR did not show prognostic significance. These findings suggest that the prognostic value of PVR may be lower than expected.