Association of homocysteine and smoking with cerebral microemboli in patients with mechanical heart valves: a transcranial Doppler study

Objectives: Microembolic signals (MES) on transcranial Doppler (TCD) predict stroke and cognitive decline. Plasma levels of total homocysteine (tHcy), a prothrombotic factor, are higher in patients with microemboli in carotid stenosis and in patients with paradoxical embolism. In this study we assessed the association between the level of tHcy and the number of MES in patients with mechanical heart valves (MHVs). Methods: TCD monitoring was performed to detect MES before and after breathing 100% oxygen and repeated every 2-4 weeks up to six times. Results: Twenty-five patients with MHVs (mean age: 63.60±10.15 years) participated in this study; 15 were men (66.47±7.25 years) and 10 were women (59.30±12.60 years). In total, there were 126 study visits. In multiple regression, higher tHcy was associated with more MES in both preoxygenation (OR 1.34 (95% CI 1.07 to 1.68, P=0.009)) and postoxygenation (OR 1.40 (95% CI 1.07 to 1.83, P=0.01)) phases. Current smoking and the length of time between the operation and monitoring also correlated with a higher number of MES before and after breathing oxygen, particularly in women. Conclusions: Higher tHcy and smoking were associated with a higher MES count in both preoxygenation and postoxygenation phases. Because smoking can be stopped and hyperhomocysteinaemia is treatable, these are clinically important findings.