Differences in non-flow limiting non-culprit plaque characteristics after myocardial infarction in patients with versus without chronic kidney disease

Abstract Background Patients with chronic kidney disease (CKD) are at increased risk for recurrent cardiovascular events after myocardial infarction compared to patients with preserved renal function. This disparity may be related to differences in plaque morphology. Purpose To compare non-flow limiting non-culprit (NC) plaque characteristics as assessed by optical coherence tomography in patients with versus without chronic kidney disease presenting with myocardial infarction. Methods 438 patients presenting with myocardial infarction with additional non-flow limiting (defined as a fractional flow reserve >0.80) NC lesions were included in the prospective observational PECTUS-obs study after treatment of the infarct related artery. An independent core laboratory performed all quantitative and qualitative OCT analyses. For the present subgroup analysis, patients were grouped according to the presence or absence of CKD, which was defined as an estimated glomerular filtration rate (eGFR) <60 ml/min/1.73 m². Baseline characteristics were compared between groups on a patient-level and OCT characteristics were compared on a lesion-level while accounting for within-patient clustering. Results Out of 420 patients with at least one analyzable OCT, baseline renal function was known in 416. Among them, there were 55 patients with and 361 patients without CKD (mean eGFR 47.4 ± 9.2 vs 84.7 ± 15.0 ml/min/1.73 m², p<0.001). Patients with CKD were older (mean age 73 ± 9 vs 62 ± 10 years, p<0.001), more frequently were female (29.1% vs 17.2%, p=0.035) and predominantly presented with a non-ST-segment elevation myocardial infarction (72.2% vs 44.9%, p<0.001). Comorbid disease was more prevalent among patients with CKD, including a higher prevalence of hypertension (p=0.010), hypercholesterolemia (p=0.020), diabetes (p<0.001), history of myocardial infarction (p<0.001), carotid artery disease (p=0.019) and peripheral artery disease (p=0.002). Coronary lesions in patients with CKD on average had a larger maximal calcium arc (188 ± 114 vs 137 ± 87º, p=0.003) and length (11.9 ± 10.3 vs 8.4 ± 7.4 mm, p=0.021). Lipid plaques were less prevalent among lesions in patients with CKD (63.6% vs 78.0%, p=0.016) and less frequently had a lipid arc ≥90º (60.6% vs 76.1%, p=0.018). Although the mean minimal fibrous cap thickness was lower in patients with CKD (p=0.025), no difference was observed in the prevalence of thin-cap fibroatheromas (p=0.984) or high-risk plaques according to the PECTUS-obs criteria (p=0.665). Conclusion Non-flow limiting NC lesions in patients with CKD differ from those in patients without CKD in a cohort of patients presenting with myocardial infarction. Overall, plaques in patients with CKD show more extensive calcification, whereas lesions in patients without CKD more often consist of lipid plaques, but the prevalence of high-risk plaques was comparable.