Impact of small body surface area on clinical and culprit lesion characteristics and outcomes in Japanese patients with acute coronary syndrome

Background: The disadvantages of small body size in patients with cardiovascular disease have not been fully investigated. The aim of our current study is to examine the impact of body surface area (BSA) on clinical characteristics and outcomes in patients with acute coronary syndrome (ACS). Methods: Patients with ACS (n=1829) were retrospectively compared in the small BSA (S-BSA; BSA <1.65 m2), medium BSA (M-BSA; BSA 1.65–1.80 m2) and large BSA (L-BSA; BSA>1.8 m2) groups. Optical coherence tomography (OCT) findings were also compared among groups. Results: The frequency of in-hospital left ventricular rupture was higher in the S-BSA group than in the M-BSA and L-BSA groups (3% vs. 1% vs. 1%, p<0.001). Peak creatine kinase-MB levels were lower in the S-BSA group (median [U/L]; 83 vs. 94 vs. 106). OCT data showed that distal (median [mm2]; 4.26 vs. 4.90 vs. 5.00, p=0.003) and proximal (median [mm2]; 6.00 vs. 6.61 vs. 7.14, p<0.001) reference lumen areas were smaller in the S-BSA group. Calcified plaques were more common in the S-BSA group (51% vs. 45% vs. 37%, p=0.008). The S-BSA group had significantly higher incidences of cardiovascular death (11.2% vs. 3.3% vs. 5.7%, p<0.001), major bleeding (11.2% vs. 3.3% vs. 5.7%, p<0.001) and rehospitalization for heart failure (6.1% vs. 3.8% vs. 2.8%, p=0.033%) during the two-year follow-up period. Conclusion: ACS patients with a small BSA had smaller vessels and more advanced atherosclerosis than those with a larger BSA, and showed a higher prevalence of two-year adverse events.