The value of brain natriuretic peptide in the prosthetic valve thrombosis

Abstract

We aimed to investigate how prosthetic valve thrombosis (PVT) affects brain natriuretic peptide (BNP) levels and how BNP changes following thrombolytic therapy. The study included 70 consecutive patients with left-sided mechanical PVT who received thrombolytic therapy. The patients were divided into two groups, namely obstructive thrombus (n = 42) and nonobstructive thrombus (NOT, n = 28). BNP levels of patients were assessed before and after thrombolytic therapy. BNP levels were higher in obstructive thrombus group than NOT group in whole study population, in patients with mitral PVT and in patients with aortic PVT [325.0 (189.5-496.0) vs. 84.0 (44.5-140.0), P < 0.001, 323.0 (193-449.0) vs. 59.0 (37.0-131.0), P < 0.001 and 321.0 (132.0-525.0) vs. 99.0 (60.5-173.0), P < 0.001]. BNP levels were positively correlated with transmitral and transaortic mean gradients, and negatively correlated with mitral valve area (r: 0.374, P = 0.013; r: 0.432, P = 0.035 and; r: -0.642, P < 0.001, respectively). BNP values above 165 pg/ml may predict the presence of obstructive thrombus with a sensitivity of 88.0%, and a specificity of 79.0% (AUC = 0.928, 95% confidence interval: 0.871-0.986, P < 0.001). Following thrombolytic therapy, BNP levels (pg/ml) significantly decreased from 325.0 (189.5-496.0) to 137.0 (101.7-224.5), P < 0.001, in all patients with obstructive thrombus, from 323.0 (193.0-449.0) to 129.0 (98.0-223.0), P < 0.001, in patients with only mitral obstructive thrombus and from 321.0 (132.0-525.0) to 181.0 (99.0-217.5), P < 0.001, in patients with only aortic obstructive thrombus. BNP levels are significantly higher in prosthetic valve patients with obstructive thrombus than in those with NOT and decrease in patients with obstructive thrombus after thrombolytic therapy. A cut off value of BNP of at least 165.0 pg/ml was found to discriminate obstructive thrombus from NOT.