Plasma N-terminal pro BNP and cardiotrophin-1 are elevated in aortic stenosis

Background: Echocardiography with Doppler examination of the aortic valve p rovides a very accurate assessment of the transvalvular gradient and is use d to monitor progression of aortic stenosis (AS). Plasma brain natriuretic peptide (BNP) has been shown to correlate with end-systolic wall stress in patients with AS. Aim: We hypothesized that plasma N-terminal proBNP (NT pr oBNP) and a newly identified cytokine cardiotrophin-1 (CT-1), which has bee n shown to stimulate BNP production at a transcriptional level are elevated in patients with AS and correlate to the maximum trans-valvular aortic pre ssure gradient (TVPG). Method: We compared plasma NT proBNP and CT-1 in 15 AS patients [five males, mean age 79 years [range 60-94], mean TPVG 39.3 mm Hg (20-100)] with 10 controls (five male, mean age 68 years [56-79]). Resul ts are expressed as mean [ranges] and comparisons were by the Mann-Whitney test. Results: NT proBNP levels were elevated in AS patients [252.9 fmol/ml (79.2-541.8)] when compared with the controls (157.2 fmol/ml [104.7-236.9] , P < 0.005). Also CT-1 levels were elevated in AS patients (57.3 fmol/ml [ 33-86.3] when compared with the controls [28.3 fmol/ml (6.9-48.3), P < 0.00 05]. Both NT proBNP and CT-1 levels were correlated to the TVPG (r = 0.53 a nd r = 0.65, P < 0.05 and P = 0.009, respectively). On best subset analysis the strongest correlate with TVPG was CT-1 (R-2 = 38%). The addition of NT proBNP did not improve diagnostic accuracy (R-2 = 39%). Conclusion: These results suggest NT proBNP and CT-1 levels increase in proportion to the TVP G and could potentially be used to monitor progression of disease non-invas ively. These markers may also be useful to identify the optimum time for su rgery in AS. (C) 2001 European Society of Cardiology. All rights reserved.