Introduction: The influence of environmental risk factors on the clinical manifestation of non-obstructive coronary artery disease (nobCAD) has not been studied in detail.
Hypothesis: We explored the relationship between the history of smoking and the grade of angina in nobCAD patients.
Methods: Among 1378 recruited patients who had no relevant coronary stenosis (i.e. ≥ 50%) in the coronary angiography, nobCAD was defined by the history of angina pectoris symptoms assessed by the Rose questionnaire. Traditional cardiovascular risk factors including the history of smoking were evaluated in all patients using a standardised interview.
Results: NobCAD was identified in 813 patients (407 men [50.1%]; mean age 61 years [IQR: 53 -70]) divided in the following subgroups according to the chest pain character: 1.definite angina (n=265; 33%), 2. probable angina (n=335; 41%), and non-anginal chest pain (n=213; 26%). The prevalence of smokers and ex-smokers was similar in patients with nobCAD chest pain versus controls [smokers: 102 (12.6%) vs. 77 (13.7%); ex-smokers: 283 (34.9%) vs. 214 (38%). After adjustment for other traditional cardiovascular risk factors, previous statin treatment, the presence of coronary atherosclerosis, and NYHA class, current/previous tobacco consumption remained a predictor of the presence of definite angina [OR 95%CI: 1.509 (1.031-2.207); p=0.034]. Considering the same confounders, current tobacco smoking associated with increased risk of definite angina across the age categories [HR 95%CI: 4.327 (2.797-6.695); p=4.7 -11 for comparison between smokers vs. non-/ex-smokers]. The risk of definite angina was lower in ex-smokers when compared with current smokers [HR 95%CI: 0.351 (0.216-0.571); p=2.5 -05] (see the graph).
Conclusions: Current tobacco consumption associates with higher probability of exertion-related, microvascular angina pectoris. These results suggest the potential benefit of smoking cessation in nobCAD patients.