Role of pulmonary arterial capacitance in predicting mortality in patients with pulmonary hypertension: A systematic review and meta-analysis

Background: Pulmonary arterial capacitance or compliance (PAC) has been reported as an independent predictor of mortality in patients with pulmonary arterial hypertension (PAH) and pulmonary hypertension secondary to left heart disease (PH-LHD). Methods: We conducted a literature search of PubMed/Medline, Google Scholar, and Cochrane library databases from July 30th to September 4th, 2020, and identified all the relevant studies reporting mortality outcomes in patients with PAH and PH-LHD. Pooled data from these studies were used to perform a meta-analysis to identify the role of PAC in predicting all-cause mortality in this subset of patients. Results: Pooled data on 4997 patients from 15 individual studies showed that the mortality risk in patients with PAH and PH-LHD varies significantly per unit change in PAC either from baseline or during follow-up. A reduction in PAC per 1 ml/mmHg was associated with a 4.25 times higher risk of all-cause mortality (95% CI 1.42–12.71; p = 0.021) in PAH patients. Among patients with PH-LHD, mortality risk increased by ~30% following a unit decrease in PAC (HR, 1.29; p = 0.019), whereas an increase in PAC by 1 ml/mmHg lowered the mortality risk by 30% (HR, 0.70). Conclusion: PAC is a strong and independent predictor of all-cause mortality in both patients with PAH and PH-LHD. A decrease in PAC by 1 ml/mmHg from baseline or during follow-up significantly increases the risk of all-cause mortality among both patients with PAH and PH-LHD. Treatment modalities targeted at PAC improvement can affect the overall survival and quality of life in such patients.