N-terminal Pro-B-type natriuretic peptide and its correlation to haemodialysis-induced myocardial stunning.
BACKGROUND
Haemodialysis (HD) is able to induce recurrent myocardial ischemia and segmental left-ventricular dysfunction (myocardial stunning). The association of N-terminal Pro-B-type natriuretic peptide (NTpro-BNP) with HD-induced myocardial stunning is unclear.


METHODS
In 70 prevalent HD patients, HD-induced myocardial stunning was assessed echocardiographically at baseline and after 12 months. The extent to which pre-dialysis NTpro-BNP was associated with the occurrence of HD-induced myocardial stunning was assessed as the primary endpoint.


RESULTS
The median Ntpro-BNP concentration in this cohort was 2,154 pg/ml (IQR 1,224-3,014). Patients experiencing HD-induced myocardial stunning at either time point displayed elevated NTpro-BNP values (2,418 pg/ml, IQR, 1,583-3,474 vs. 1,751 pg/ml, IQR (536-2,029), p = 0.02). NTpro-BNP levels did not differ between patients showing HD-induced stunning at baseline and those developing stunning during the observational period (p = 0.8). NTpro-BNP levels drawn at the beginning of the dialysis session achieved a poor diagnostic accuracy for the detection of myocardial stunning (area under the ROC curve 0.61, 95% CI 0.45-0.77), but provided an accurate rule out for myocardial stunning during the subsequent year (AUC 0.85, 95% CI 0.70-0.99). The calculated cut-off of 1,570 pg/ml achieved a sensitivity of 66% and a specificity of 78% for the exclusion of myocardial stunning at any time point. In logistic regression analysis, only low NTpro-BNP levels (OR 0.92 for every additional 100 pg/ml, 95% CI 0.85-0.99, p = 0.03) were significantly associated with absence of myocardial stunning at any time point.


CONCLUSION
Predialytic NTpro-BNP levels fail to adequately diagnose current dialysis-induced myocardial stunning, but help to identify patients with a propensity to develop dialysis-induced myocardial stunning at any time during the next 12 months.