Background: The strategy for cardiovascular surgery in dementia patients is controversial, so we aimed to investigate whether preoperative dementia and its severity might affect the outcomes of cardiovascular surgery by evaluating with the Mini-Mental State Examination (MMSE). Methods and Results: The study group comprised 490 patients undergoing cardiovascular surgery. Their preoperative cognitive status was evaluated using the MMSE, and analysis was performed to compare the patients with MMSE score <24 (dementia group, n=51) or MMSE score 24-30 (non-dementia group, n=439). Furthermore, the effect of the severity of dementia was analyzed with a cut-off MMSE score of 19/20. Risk factors for surgical outcomes were explored using multivariate logistic regression analysis. Hospital mortality was 11.8% in the dementia group and 2.1% in the non-dementia group (P=0.002). Regarding the postoperative morbidities, the incidence of cerebrovascular disorder (P=0.001), pneumonia (P=0.039), delirium (P=0.004), and infection (P=0.006) was more frequent in dementia group. Among the patients with MMSE <20, hospital mortality was as high as 25%, and the rate of delirium was 58%. Multivariate logistic regression analysis revealed that MMSE score <24 (P=0.003), lower serum albumin (P=0.023) and aortic surgery (P=0.036) were independent risk factors for hospital death.
Conclusions: Preoperative dementia affects the outcomes of cardiovascular surgery with regard to hospital death and delirium. The surgical indication for patients with MMSE <20 might be difficult, but surgery with an appropriate strategy should be considered for patients with MMSE <24.
Keywords: Cardiovascular surgery; Dementia; Mini-Mental State Examination.