Body size–normalized quantitative assessment of coronary lumen volume following sublingual nitroglycerin at CT angiography

Abstract

Sublingual nitroglycerin is widely used before coronary computed tomography angiography to induce coronary vasodilation and enhance visualization of distal coronary segments and small side branches. The aim of the study was to assess the effect of sublingual nitroglycerin on whole-vessel coronary lumen volume in coronary computed tomography angiography and to determine whether this response varies after normalization for body size parameters. This single-center retrospective comparative study included patients who underwent coronary computed tomography angiography using a 128-detector computed tomography scanner. Patients were classified according to pre-scan nitroglycerin administration. In the nitroglycerin group, 400 µg of sublingual nitroglycerin was administered 3–5 minutes before image acquisition. Age-matched patients who did not receive nitroglycerin served as controls. Coronary lumen volumes were calculated semi-automatically using dedicated software and normalized to body mass index and body surface area. The number of coronary side branches and intraluminal contrast enhancement in proximal and distal segments were also assessed. A total of 194 patients were included. Compared with controls, the nitroglycerin group demonstrated significantly larger median coronary lumen volumes (left anterior descending artery: 519 vs 429 mm 3 , right coronary artery: 634 vs 468 mm 3 , left circumflex artery: 381 vs 249 mm 3 ), together with higher body size-normalized lumen volumes (all p ≤ 0.009). The number of septal, diagonal, and obtuse marginal branches was also significantly higher in the nitroglycerin group ( p < 0.001). The proximal-to-distal contrast enhancement ratios of the left anterior descending and left circumflex arteries were significantly lower in the nitroglycerin group ( p < 0.001). Sublingual nitroglycerin significantly increases whole-vessel coronary lumen volume on coronary computed tomography angiography. This quantitative volumetric effect persists after body size normalization and may improve coronary visualization in patients with larger body habitus.