Frank's sign (diagonal earlobe crease, DELC) has been described as a dermatological marker for coronary artery disease.

This study investigates its correlation with the complexity of coronary lesions assessed by SYNTAX score.

Prospective observational study conducted from May to September 2024 at Sahloul Hospital's Cardiology Department. Patients undergoing coronary angiography were enrolled after consent. Frank's sign was analyzed using Prangenberg's classification (grades 1–3). SYNTAX scores were stratified into three levels: low (≤ 22), intermediate (23–32), and high ( > 33).

A total of 92 patients were included (61% male, median age: 63 years). Frank's sign was present in 80% of patients. No significant correlation was found between age and the presence of the sign ( P = 0.2). The prevalence of Frank's sign was significantly higher in patients with intermediate and high SYNTAX scores compared to those with low scores ( P = 0.021). Mean SYNTAX scores: 8.16 ± 1.9 (absence of sign), 10.5 ± 2.4 (grade 1), 18.17 ± 3.14 (grade 2), 19.35 ± 3.11 (grade 3), and 15.4 ± 2.4 (grade 4) ( Fig. 1 ). The association between the grade of Frank's sign and SYNTAX score was not statistically significant ( P = 0.18).

Frank's sign may serve as a simple clinical marker predictive of complex coronary lesions. This correlation could be explained by the similar vascular anatomy of the earlobe and heart, both supplied by terminal arteries without collateral circulation. A larger multicenter study is needed to confirm this association.