Background: The SYNTAX score is an angiographic score that predicts coronary artery disease (CAD) complexity. It has been shown to be useful for decision making about percutaneous coronary intervention or coronary artery bypass grafting among patients with CAD. Higher SYNTAX scores are indicative of more complex disease. Chronic obstructive pulmonary disease (COPD) is characterised by limitation of airflow. Measurement of forced expiratory volume in one second (FEV1) in spirometry is used for diagnosis and to determine the severity of the disease.

Aim: To evaluate the relationship between FEV1 and SYNTAX score in patients with COPD.

Methods: Seventy-eight patients with a previous diagnosis of COPD and 48 patients without COPD were enrolled. Spirometry and coronary angiography were performed in all patients. SYNTAX score was calculated and compared between the two groups. The correlation between FEV1 and SYNTAX score was analysed.

Results: SYNTAX score was higher in patients with COPD than in patients without COPD (23.22 ± 12.10 vs. 17.92 ± 11.21, respectively; p = 0.013). Multivariate analysis demonstrated that COPD was independently predictive for intermediate and high SYNTAX score (odds ratio 4.833; 95% confidence interval 2.228–10.485; p < 0.001). Mean FEV1 (% predicted) was 64.7 ± 11.4 and negatively correlated with SYNTAX score in COPD group (r = –0.266 and p = 0.018). The receiver operating characteristic analysis yielded a cutoff value of 65.5 for the FEV1 to predict SYNTAX score ≥ 23, with sensitivity and specificity being 78.6% and 70%, respectively.

Conclusions: COPD is a predictor of higher SYNTAX scores. FEV1 is associated with more severe and complex CAD.