Effect of the ratio of vessel-specific volume to fractional myocardial mass on fractional flow reserve

This study aimed to examine whether the ratio of vessel-specific coronary arterial lumen volume to the fraction of myocardial mass (V R /M R ) affects myocardial ischemia. We proposed a calculation method for V R /M R , and compared the ratio of total epicardial coronary arterial lumen volume to left ventricular myocardial mass (V/M) with V R /M R in predicting myocardial ischemia. V R /M R and V/M were computed using data from 205 patients with 241 stenosis vessel who underwent coronary computed tomography angiography (CTA), quantitative coronary angiography, and fractional flow reserve. The vessel-specific coronary arterial lumen volume (V R ) was obtained from CTA by segmenting the coronary arterial lumen volume, while the vessel-specific fraction of myocardial mass (M R ) was obtained by allometric scaling. The V R /M R was then calculated. The cut-off values of V/M (23.55 mm 3 /g) and V R /M R (12.98 mm 3 /g) were used to define equal groups of ischemic and non-ischemic patients, respectively. Using these cut-off values, the accuracy, specificity, sensitivity, positive predictive value, and negative predictive value of V/M were 60%, 76%, 45%, 57%, and 66%, and of V R /M R were 87%, 92%, 77%, 89%, and 83%, respectively. Patients have different V R /M R values in different stenotic coronary arteries. Clinically, V R /M R is a quantitative indicator of the risk of myocardial ischemia.