Background: Plasma brain natriuretic peptide (BNP), a cardiac hormone secreted mainly by the cardiac ventricles, has been shown to increase in proportion to the degree of cardiac overload. However, whether plasma BNP may serve as a marker for the efficacy of pulmonary thromboendarterectomy in patients with chronic thromboembolic pulmonary hypertension remains unknown.
Methods: Plasma BNP level was measured in 34 patients with chronic thromboembolic pulmonary hypertension before and 1 month after pulmonary thromboendarterectomy. Right heart catheterization was also performed before and 1 month after the operation.
Results: Preoperative plasma BNP level was significantly elevated in patients with chronic thromboembolic pulmonary hypertension compared with control patients (246 +/- 40 vs 13 +/- 2 pg/mL; p < 0.001; n = 34) and was positively correlated with total pulmonary resistance (r = 0.57; p < 0.001). After pulmonary thromboendarterectomy, plasma BNP level in survivors markedly decreased (220 +/- 31 to 54 +/- 9 pg/mL; p < 0.001; n = 32) in association with a reduction of total pulmonary resistance (15.6 +/- 1.0 to 4.5 +/- 0.3 Wood units; p < 0.001). The change in plasma BNP level was closely correlated with that in total pulmonary resistance (r = 0.63; p < 0.001). Importantly, a sustained elevation of plasma BNP (> or = 50 pg/mL) indicated the presence of residual pulmonary hypertension (> or = 5 Wood units) after operation (sensitivity = 73%; specificity = 81%).
Conclusions: Plasma BNP level was strongly associated with the severity of pulmonary hypertension in patients with chronic thromboembolic pulmonary hypertension and thereby may serve as a noninvasive marker for the efficacy of pulmonary thromboendarterectomy.