Association of Cardiac Valve Calcification and 1-year Mortality after Lower-extremity Amputation in Diabetic Patients: A Retrospective Study

Background: Cardiac valve calcification predisposes patients to a higher risk of adverse cardiovascular events. This study aimed to investigate the association between cardiac valve calcification and 1-year mortality in diabetic patients after lower-extremity amputation. Methods: This was a retrospective study conducted on the clinical data of diabetic patients who underwent lower-extremity amputation admitted to the Sun Yat-sen Memorial Hospital, Guangzhou, Guangdong, China for diabetic foot ulcers needed lower extremity amputation surgery between July 2017 and March 2021. Detailed preoperative medical assessments were performed and recorded. Cardiac valve calcification was assessed using echocardiography at baseline. Oneyear follow-up assessments were conducted and included clinical visits, hospital record assessments, and telephone reviews to obtain the survival status of patients. Results: Ninety-three diabetic patients participated in the study. The 1-year follow-up mortality rate after amputation was 24.7%. Compared to the survival group, the prevalence of cardiac valve calcification and the Revised Cardiac Risk Index [RCRI] were higher in the mortality group. In the Cox regression analysis, cardiac valvular calcification [HR=3.427, 95% CI=1.125- 10.443, P=0.030] was found to be an independent predictor of all-cause mortality after amputation. In addition, the patients with both aortic valve calcification and mitral annular calcification had a higher all-cause mortality rate [50%]. Receiver operator characteristic curve analysis showed a stronger predictive ability when using a combination of calcified valve number and RCRI [AUC=0.786 95%, CI=0.676-0.896, P=0.000]. Conclusion: In diabetic patients after lower-extremity amputation, cardiac valve calcification was associated with all-cause mortality during 1-year follow-up. Combination of calcified valve number and RCRI score showed a stronger predictive value for mortality.