Validity of tortuosity severity index in chest pain patients with abnormal exercise test and normal coronary angiography

Background: Coronary tortuosity (CT) had different definitions and scores in literature with unclear pathophysiological impact. Objectives: To study degree of CT and it's relation to ischemic changes in patients with angina but normal coronary angiography (CA). Methods: We conducted a prospective study at University hospitals between May 2016 and January 2017. We included 200 consecutive patients who underwent CA due to chest pain assumed to be of cardiac origin, and their CA was normal (no diameter stenosis >30%, nor myocardial bridging). Patients were prospectively divided into 2 groups based on the presence (n = 113) or absence (n = 87) of ischemic changes during stress study and compared for clinical, echocardiographic and CA characteristics. A newly proposed Tortuosity Severity Index (TSI) was developed into significant (mild/moderate CT with more than 4 curvatures in total, or severe/extreme CT with any number of curvatures) or not significant TSI (mild CT with curvatures less than or equal to 4 curvatures in total). Results: Patients with ischemic changes had the highest rate of CT (76.5 vs 18%, p = 0.004) compared to those without. CT mostly affects the left anterior descending (LAD) coronary artery in mid and distal segments. Females, elderly, and hypertensives with left ventricular hypertrophy were strongly related to CT. Multivariate logistic regression analysis identified CT with significant TSI as the only predictor of ischemic changes in these patients (OR = 6.2, CI = 2.5–15.3, P = <0.001). Conclusions: Coronary tortuosity is a strong predictor of anginal pain among patients with normal CA, despite positive stress study. This finding is more pronounced among elderly, hypertensive female patients.