Fig 1.
We excluded 14 patients from the initial 57 patients due to significant fixed stenosis (n = 8) or inconsistency between the CCTA and spasm provocation test (n = 6). Finally, 43 patients were selected for analysis. CCTA, coronary computed tomography angiography.
Fig 2.
A representative case of the focal-type spasm on CCTA and the ergonovine provocation test.
A 59-year-old male patient presented with intractable recurrent chest pain. (A) Baseline CT (upper) revealed significant focal stenosis at the distal RCA on volume rendering and curved multiplanar images. IV nitrate CT (lower) revealed completely dilated coronary arteries without narrowing. (B) Baseline coronary angiography (left) revealed intermediate luminal stenosis of the distal RCA. Upon ergonovine infusion (middle), RCA showed complete luminal occlusion. After nitrate injection, RCA showed full dilation without evidence of a stenotic lesion (right). The TAG values were -8.80 and -0.90 for baseline CT and IV nitrate CT, respectively. CCTA, coronary computed tomography angiography; CT, computed tomography; IV, intravenous; RCA, right coronary artery; TAG, transluminal attenuation gradient.
Fig 3.
A representative case of the diffuse-type spasm on CCTA and the ergonovine provocation test.
A 58-year-old male patient presented with chest pain. (A) Baseline CT (upper) revealed a diffuse small diameter with a beaded appearance throughout the coronary arteries at the distal RCA on volume rendering and curved multiplanar images. IV nitrate CT (lower) showed completely dilated coronary arteries without narrowing. (B) Baseline coronary angiography (left) demonstrated diffuse narrowing of the whole coronary branches, which was consistent with the findings on baseline CCTA (A). The TAG values were -19.87 and -13.89 on baseline CT and IV nitrate CT, respectively. CCTA, coronary computed tomography angiography; CT, computed tomography; IV, intravenous; RCA, right coronary artery; TAG, transluminal attenuation gradient.
Table 1.
General characteristics of the enrolled subjects.
Fig 4.
Per vessel analysis of spasm type for coronary spasm on CCTA.
A total of 43 patients (129 vessels) were analyzed based on their spasm types. In LAD, LCX, and RCA, 14 (33%), 7 (16%), and 8 (18%) vessels showed the diffuse type, while the corresponding values for the focal type were 7 (16%), 0 (0%), and 2 (5%) vessels. LAD, left anterior descending artery; LCX, left circumflex artery; RCA, right coronary artery; Spasm (-), patients without vessels showing spasm; Spasm (+), patients with vessels showing spasm; Focal (type), significant focal stenosis without definite plaques; Diffuse (type), diffuse small diameter (< 2 mm) with serrated margin and loss of diameter tapering.
Table 2.
Per vessel analysis for coronary spasm on CCTA.
Table 3.
TAG and ProxHU values for the vessel types on baseline CT and IV nitrate CT.
Fig 5.
Correlation between the TAG and ProxHU values of coronary arteries.
ProxHU values showed a weak negative correlation with TAG values (Baseline CT, r = -0.360; P<0.001; IV nitrate CT, r = -0.385; P<0.001). This trend was observed regardless of the CT acquisition method.
Fig 6.
Comparison of TAG and ProxHU values between spasm(-) and spasm(+) vessels in baseline CT (A, B) and IV nitrate CT (C, D). In the baseline CT, the TAG of LCX was significantly lower values in spasm(+) vessels than in spasm(-) vessels; however there was no significant difference for that of LAD and RCA. The ProxHU values of LAD exhibited lower values in spasm(+) vessels than in spasm(-) vessels, while the other vessels did not show significant differences in baseline CT. For IV nitrate CT, there was no significant difference in the TAG or ProxHU values between the spasm(+) and (-) vessels for all three vessels. Spasm (-), patients without vessels showing spasm; Spasm (+), patients with vessels showing spasm; TAG, transluminal attenuation gradient; ProxHU, most proximal CT number of each coronary arteries; LAD, left anterior descending artery; LCX, left circumflex artery; RCA, right coronary artery.
Table 4.
Subgroup analysis of spasm (+) vessels on baseline CT.
Table 5.
Comparison of intra-subject differences in TAG values among normal, focal and diffuse spasm (+) vessels.