Effect of statin therapy on coronary inflammation assessed by pericoronary adipose tissue CT attenuation

Pericoronary adipose tissue (PCAT) attenuation on coronary computed tomography angiography (CCTA) is an imaging biomarker of coronary inflammation. The natural history of PCAT attenuation remains unknown. High-intensity statin therapy has pleiotropic anti-inflammatory effects. We sought to assess temporal changes in PCAT attenuation in patients with and without statin therapy. This was a multicentre observational study that included consecutive patients with stable coronary artery disease (CAD) undergoing clinically indicated serial CCTA with identical scan parameters ≥ 12 months apart between May 2013 and July 2022. Using semi-automated software, PCAT attenuation was measured on a per-lesion level (PCATlesion) and per-patient level around the proximal right coronary artery (PCATRCA). Of 96 patients (57±11 years, 60% male), 34 patients were not on a statin at baseline or follow-up (statin-naive), 26 patients were commenced on a statin after the baseline scan (statin-commenced), and 34 patients were on a statin at both time points (statin-continued). There was no significant difference between the groups for age, sex, BMI, and prevalence of traditional cardiovascular risk factors except for dyslipidaemia (25.0% vs 34.6% vs 64.7%, p<0.01 for trend). At a median follow-up of 3.8 years, there was a significant reduction in PCATlesion in the statin-commenced (-79.4±11.7 to -86.5±10 HU, p<0.001) and the statin-continued (-83.5±8.5 to -90.6±8.5 HU, p=0.001) groups. Meanwhile, no significant difference in PCATlesion was observed in the statin-naïve group (-84.4±9.7 to -86.6±9.5, p=0.1). Multivariate analysis showed statin intensity and LDL change to be independently associated with percentage change of PCATlesion, after correcting for cardiovascular risk factors, changes in body weight and coronary artery calcium score. Statin therapy was associated with a reduction in PCATlesion, while no significant change in PCATlesion was observed without statin therapy. If validated in larger studies, PCAT attenuation could potentially be used to monitor the response of the coronary arteries to statins and guide treatment.