B-type natriuretic peptide identifies silent myocardial ischaemia in stroke survivors

Objective: To test the hypothesis that B-type natriuretic peptide (BNP) predicts reversible myocardial ischaemia in stroke survivors who do not have chest pain or previous myocardial infarction. Methods: 56 stroke survivors (mean (SE) age 68 (8) years) underwent tetrofosmin myocardial perfusion scanning with dipyridamole as the stressor. The degree of ischaemia was assessed by a scoring system (out of 64) by an experienced observer blinded to the results of BNP. Results: In the whole cohort, BNP was significantly correlated with the degree of myocardial ischaemia on stress scanning (Spearman's r = -0.475, p < 0.001). BNP also correlated with the degree of reversible ischaemia (stress score 2 rest score; Spearman's r = 0.28, two tailed p = 0.049). In the cohort who did not have left ventricular systolic dysfunction (n = 44), BNP remained higher in patients with relevant myocardial ischaemia (mean (SE) BNP 20.9 pg/ml, 95% confidence interval (CI) 15.2 to 26.5 v 12.2 pg/ml, 95% CI 5.95 to 18.5; p = 0.046); 33 of the 44 patients had no chest pain or history of myocardial infarction. The relation between resting BNP and both inducible ischaemia and dipyridamole stress score remained significant (Spearman's r = 0.37 and -0.38, respectively). Conclusions: BNP correlates with the degree of reversible myocardial ischaemia in patients who do not have chest pain or a history of myocardial infarction or evidence of left ventricular systolic dysfunction. Stroke survivors with a high BNP deserve further investigations to rule out significant reversible myocardial ischaemia, in order to reduce their risk of cardiac death.