Prognostic impact of Achilles tendon thickening after percutaneous coronary intervention in comparison between acute and chronic coronary syndromes

Background Achilles tendon thickening (ATT), the most common form of tendon xanthomas, serves as an important diagnostic criterion for familial hypercholesterolemia (FH). While tendon xanthomas are highly specific markers of FH patients, ATT is observed at a certain frequency even in individuals who do not meet the diagnostic criteria for FH. Previous studies have reported that the presence of ATT is associated with worse prognosis after percutaneous coronary intervention (PCI). Purpose This study aimed to investigate the prognostic impact of ATT in patients after PCI in comparison between acute coronary syndrome (ACS) and chronic coronary syndrome (CCS). Methods Patients who had undergone successful PCI between June 2016 and June 2022 and measured Achilles tendon thickness using soft X-ray radiography were retrospectively examined. ATT was defined as having Achilles tendon thickness of ≥8.0 mm in men and ≥7.5 mm in women, according to the method in conformity with the guidelines proposed by the Japan Atherosclerosis Society (JAS) in 2022. FH was diagnosed according to the criteria in the JAS guidelines. The incidence of major adverse cardiovascular events (MACE), a composite of all-cause death, nonfatal myocardial infarction, stent thrombosis, stroke, and target vessel revascularization, was investigated for up to 3 years. Results Of 1,362 patients enrolled in this study, ATT was observed in 228 (16.7%) patients, and there were 53 (3.9%) patients diagnosed with FH, which included 50 (3.7%) FH patients with ATT and 3 (0.2%) FH patients without ATT. In the overall population, patients with ATT had a significantly higher incidence of MACE at 3 years compared to those without (28.4% vs. 17.9%, p<0.001). In subgroup analyses of ACS (n=387) and CCS (n=975) patients, ACS patients showed a higher incidence of MACE at 1 year in the ATT group (p<0.001) and no significant difference in the landmark analysis beyond 1 year between the 2 groups (p=0.396). CCS patients had no significant difference in the incidence of MACE at 1 year (p=0.809) and a higher incidence in the ATT group in the landmark analysis beyond 1 year (p=0.030) (Figure). Similar results were observed in the population excluding FH patients. Conclusions In patients after PCI for coronary artery disease, ATT was significantly associated with the increased risk of MACE. In patients with ATT, the prognosis differed based on whether they had ACS or CCS and the timing after PCI. ATT may be useful for risk stratification of clinical outcomes after PCI in both ACS and CCS patients.