Slow flow phenomenon in coronary artery aneurysm or ectasia. Analysis from the CARED-POL Registry

Background Coronary artery aneurysm or ectasia (CAAE) significantly alters intracoronary hemodynamics, which can lead to the coronary slow flow phenomenon (CSFP), even in the absence of obstructive atherosclerosis [1]. While CSFP is associated with recurrent ischemia and hospitalizations [2], its prevalence and specific predictors within the CAAE population are not well studied. Furthermore, the lack of standardized CSFP management protocols in aneurysmal disease poses a major challenge for risk assessment. Purpose To assess the prevalence of CSFP in patients with CAAE and to identify clinical and angiographic predictors of impaired coronary perfusion within this population. Methods We performed a retrospective analysis of 342 patients from the CARED-POL database who were diagnosed with CAAE. Patients were stratified into slow-flow (n=144) and non-slow-flow (n=198) groups. A comprehensive assessment covered cardiovascular risk factors, clinical presentation, comorbidities, and detailed laboratory and angiographic data. Morphological analysis of aneurysmal segments focused on diameter, longitudinal extent, and intra-luminal thrombus presence. Results The prevalence of CSFP in the CAAE cohort was 42.1%. Detailed analysis revealed a distinct clinical profile for the slow-flow cohort, predominantly composed of male patients (79% vs 68,6%). Within this group, CSFP was significantly associated with greater body height (p=0.008), lower platelet counts (p=0.045) and a lower prevalence of acetylsalicylic acid (ASA) therapy (p=0.020), distinguishing it from the non-slow-flow population despite otherwise similar cardiovascular risk factors. The most prominent predictors of CSFP were morphological. The slow-flow group had a higher burden of CAAE, with more affected arteries (p<0.001) and more aneurysmal segments (p<0.001). Morphological analysis showed that larger dimensions were strongly associated with impaired flow: maximum transverse diameter (5.9 vs 5.4 mm) (p<0.001) and maximum longitudinal diameter (11.8 vs 7.7 mm) (p<0.001). Crucially, intra-CAAE thrombus was nearly four times more prevalent in the slow-flow group (50.4% vs 12.8%) (p<0.001). Long-term survival analysis showed no significant difference in all-cause mortality between the groups (p=0.88). Conclusions The presence of coronary slow flow in patients with CAAE should be considered as an important clinical indicator, primarily determined by morphological complexity and aneurysm dimensions rather than traditional cardiovascular risk factors. The present data demonstrate a strikingly high prevalence of intra-aneurysmal thrombus in the slow-flow cohort, suggesting that CSFP serves as a major marker of a prothrombotic state and a potential predictor of cardiovascular hospitalizations.