Survival in patients with borderline pulmonary arterial pressure
Background: Pulmonary hypertension (PH) is defined as an elevation of mean pulmonary arterial pressure (mPAP) ≥25 mmHg. Normal mPAP is considered to be 14 ± 3 mmHg. The prognostic relevance of mPAP between 21 and 25 mmHg is unknown.
Methods: Retrospective analysis of hemodynamics and survival of patients undergoing right heart catheterization at our center between 2006 and 2014 were performed. Patients were clustered into 4 mPAP groups: ≤17 mmHg (lower normal), 18 – 20 mmHg (upper normal), 21 – 24 mmHg (borderline PAP), ≥25 mmHg (manifest PH). Baseline characteristics including number of cardiopulmonary comorbidities were assessed. Kaplan-Meier- and multivariate COX-regression analysis for survival were performed.
Results: 547 patients were analysed (64% female, age 62 ± 14yr, mPAP 29.6 ± 15.1 mmHg). Kaplan-Meier analysis revealed worse survival in patients with upper normal- and borderline PAP as compared to patients with lower normal PAP (p < 0.05). Manifest PH patients had worse survival than patients of all other groups (p < 0.01). In addition, the number of comorbidities was a significant predictor for survival in univariate analysis (p < 0.004). Cox regression analysis revealed that mPAP (p ≤0.001; 18 – 20 mmHg: HR 1.91 95% CI 0.9 – 4.3; 21 – 24 mmHg: HR 2.2 95% CI 1.1 – 4.6; > 25 mmHg: HR 4.6 95% CI 2.6 – 8.2) is an age independent predictor for survival. In multivariate analysis there was no significant difference between the lower-normal and upper-normal PAP groups (p = 0.12). Borderline PAP elevation still showed significantly worse survival as compared to lower-normal PAP (p = 0.03).
Conclusion: Borderline-PAP elevation is associated with worse prognosis in patients at risk for PH.