Red blood cell distribution width is associated with adverse cardiovascular events after septal myectomy

Background: Red blood cell distribution width (RDW) is associated with increased morbidity and mortality in several cardiovascular diseases. However, the prognostic significance of RDW in patients with hypertrophic obstructive cardiomyopathy (HOCM) who underwent septal myectomy remains unclear as no studies have been conducted on this topic. This study aimed to assess the prognostic significance of RDW in these patients. Methods: A total of 867 adults with HOCM who underwent septal myectomy at Fuwai Hospital from 2011 to 2017 were retrospectively studied. All patients were assessed comprehensively, including their medical history, echocardiograms, and blood test results. Results: The median age of patients was 47.9 [interquartile range (IQR), 37.0-56.0] years and 61.5% of patients were men. During a median follow-up period of 32 (IQR, 17-53) months, 26 patients died and 23 had a cardiovascular death during follow-up. Compared to patients in the lowest RDW quartile, those in the highest quartile had a significantly lower 5-year survival free from all-cause and cardiovascular death (95.9% vs. 87.6%, P<0.001; 95.9% vs. 89.9%, P<0.001). Compared with lower RDW, higher RDW was significantly associated with all-cause and cardiovascular death after adjustment for age, sex, body mass index, and relevant clinical risk factors [per RDW standard deviation (SD) hazard ratio (HR) increase =1.76, 95% confidence interval (CI): 1.54-2.05, P<0.001; per RDW SD HR =1.91, 95% CI: 1.63-2.22, P for trend <0.001]. Conclusions: Higher RDW is independently associated with all-cause and cardiovascular death in patients with HOCM after septal myectomy. Therefore, this readily available biomarker could be considered as an additive biomarker for risk stratification in these patients.