Level of Perivascular Inflammation Is Significantly Lower Around the Left Internal Mammary Artery Than Around Native Coronary Arteries.

Abstract

The left internal mammary artery (LIMA) is protected from developing atherosclerosis. Perivascular inflammation, which is closely associated with atherosclerosis, can be measured by perivascular adipose tissue attenuation on computed tomography angiography. Whether the absence of atherosclerosis in LIMA is related to the lower level of perivascular inflammation is unknown. This study was performed to compare the level of perivascular inflammation between LIMA insitu and native coronary arteries in patients with coronary artery disease. A total of 573 patients who underwent both computed tomography angiography and optical coherence tomography imaging were included. The level of perivascular adipose tissue attenuation between LIMA insitu and coronary arteries was compared. Perivascular adipose tissue attenuation around LIMA insitu was significantly lower around the 3 coronary arteries (-82.9 [-87.3 to -78.0] versus -70.8 [-75.9 to -65.9]; P<0.001), irrespective of the level of pericoronary inflammation or the number of vulnerable features on optical coherence tomography. When patients were divided into high and low pericoronary inflammation groups, those in the high inflammation group had more target vessel failure (hazard ratio, 2.97 [95% CI, 1.16-7.59]; P=0.017). The current study demonstrated that perivascular adipose tissue attenuation was significantly lower around LIMA insitu than around native coronary arteries. The lower level of perivascular inflammation may be related to the low prevalence of atherosclerosis in LIMA. URL: https://www.clinicaltrials.gov; Unique Identifier: NCT04523194.