RESUMO
OBJECTIVE: The aim of the present study was to investigate the association between nitrate-induced headache (NIH) and the complexity of coronary artery lesions in patients with stable coronary artery disease (CAD). SUBJECTS AND METHODS: Two hundred and seventy-five patients with anginal chest pain who underwent coronary angiography were enrolled in the present study. NIH was defined as the presence of headache due to nitrate treatment (isosorbide mononitrate 40 mg) after excluding confounding factors. Coronary artery lesion complexity was assessed by the SYNTAX score (SXscore) using a dedicated computer software system. RESULTS: The mean SXscore was lower in the patients with NIH than in patients without NIH (7.3 ± 5.2 vs. 14.4 ± 8.5, respectively; p < 0.001). Additionally, patients with NIH had a lower rate of multivessel disease compared with those without NIH (the mean number of diseased vessels was 1.5 ± 0.7 and 2.0 ± 07, respectively; p < 0.001). In multivariate analysis, increasing age (p = 0.02) and headache (p = 0.001) were found to be independent determinants of SXscore. CONCLUSION: The present study demonstrated an independent inverse association between NIH and SXscore. The NIH could provide important predictive information about coronary artery lesion complexity in patients with stable CAD.