We read with great interest the recent article by BibbinsDomingo et al 1 on plasma brain natriuretic peptide (BNP) in outpatients with stable coronary disease. They concluded that elevated levels of BNP are independently associated with inducible ischemia in outpatients with stable coronary disease, particularly among those who have a history of myocardial infarction.Previous studies have demonstrated that transient myocardial ischemia stimulates the secretion of atrial natriuretic peptide (ANP) and N-terminal ProANP (N-ANP); because of its longer half-life, N-ANP may be a better marker than ANP for the detection of high-grade coronary artery stenosis. 2-4 However, whether plasma BNP levels are increased in patients with coronary artery stenosis who have normal left ventricular function remains unknown. To examine whether coronary artery stenosis affects plasma ANP, N-ANP, and BNP levels, we recently measured these peptide levels in 104 patients with normal left ventricular systolic function who had a suspected diagnosis of angina pectoris. 5 Plasma levels of all 3 of these natriuretic peptides were higher in patients with coronary artery stenosis (major coronary artery stenosis Ͼ75%) (nϭ65) than in those without stenosis (nϭ39), whereas hemodynamic variables were similar. Multiple logistic regression analysis revealed that N-ANP (per 100 fmol/mL increase; odds ratioϭ1.9 [95% CIϭ1.2 to 2.6], PϽ0.01), but not ANP (per 10 pg/mL increase; odds ratioϭ0.9 [95% CIϭ0.5 to 1.2], Pϭ0.41) or BNP (per 10 pg/mL increase; odds ratioϭ1.1 [95% CIϭ0.8 to 1.4], Pϭ0.73), was independently associated with coronary artery stenosis after adjusting for clinical and demographic variables. Furthermore, we measured these natriuretic peptides before and 3 to 6 months after percutaneous coronary intervention in patients with myocardial infarction of recent onset (nϭ58). Plasma levels of ANP, N-ANP, and BNP significantly decreased in patients without restenosis (nϭ46) (ANP, 91Ϯ15 to 39Ϯ7 pg/mL; BNP, 134Ϯ28.9 to 41Ϯ9 pg/mL; N-ANP, 688Ϯ81 to 407Ϯ52 fmol/mL; all PϽ0.05).In contrast, these natriuretic peptide levels did not change after coronary intervention in patients with restenosis (nϭ12) (ANP, 57Ϯ19 to 50Ϯ20; BNP, 102Ϯ35 to 57Ϯ13; N-ANP, 567Ϯ178 to 508Ϯ126; all NS). Our results support the findings of Bibbins-Domingo et al 1 ; however, we propose that N-ANP may be more useful for the discrimination of clinically significant coronary artery stenosis than BNP because of its different sites of production, mechanisms of release, and metabolic characteristics.
To the Editor:We read the correspondence 1 about the article by BibbinsDomingo et al 2 with great interest. The report by BibbinsDomingo et al 2 demonstrated elevated plasma concentrations of B-type natriuretic peptide (BNP) associated with inducible ischemia in patients with stable coronary artery disease. In contrast, Nishikimi and Matsuoka 1 suggested that N-terminal proANP (atrial natriuretic peptide) might be a more sensitive plasma marker of stable coronary artery disease than are...