Background: An echocardiographic right/left ventricular end-diastolic diameter ratio (RV/LV ratio) ≥ 0.9 is an independent predictor of poor prognosis in patients with acute pulmonary embolism. Right ventricular dilation is a common characteristic of both acute pulmonary embolism and idiopathic pulmonary arterial hypertension (IPAH). However, the prognostic value of the RV/LV ratio in patients with IPAH is unknown.
Methods: Ninety-five consecutive patients with newly diagnosed IPAH were included, 17 were re-evaluated by echocardiography after 3 - 12 months of targeted therapy. Follow-up data were obtained by telephone interviews and review of the patients' records.
Results: Higher RV/LV ratios were associated with greater functional impairment. The RV/LV ratio was positively correlated with pulmonary vascular resistance (r = 0.549, P < 0.001) and plasma N-terminal pro-brain natriuretic peptide level (r = 0.575, P < 0.001), but negatively correlated with cardiac output (r = -0.517, P < 0.001) and mixed venous oxygen saturation (r = -0.599, P < 0.001). Twenty-seven patients died during follow-up period. Sensitivity and specificity of an RV/LV ratio ≥ 0.84 for predicting death were 85.2% and 51.5%, respectively. The RV/LV ratio and body mass index were independent predictors of death by multivariate Cox analysis (P < 0.01). A baseline RV/LV ratio ≥ 0.84 or a further increase in the RV/LV ratio during targeted therapy indicated a poor prognosis (P < 0.01).
Conclusion: The RV/LV ratio helps to assess the severity of IPAH and may serve as an independent predictor of prognosis in patients with IPAH.