Preoperative Vascular Function Assessment and Perioperative Vascular Events in Patients Posted for Elective Non-cardiac Surgeries

Background: Coronary atherosclerosis is usually asymptomatic until a major cardiac event occurs. Surgery is one of the major stress factors that play a role in hastening vascular deterioration in susceptible patients. Non-invasive tests to detect atherosclerosis and endothelial dysfunction have started gaining popularity nowadays, and of the several options, carotid artery intima-media thickness (IMT) and radial artery flow-mediated dilation (FMD) are two promising tests for detecting cardiovascular impairment. Methods: This was a pilot study that was undertaken on 100 patients in a tertiary care medical center (Jawaharlal Institute of Postgraduate Medical Education & Research, Puducherry) between June 2015 and August 2016 with the aim of studying the prevalence of endothelial dysfunction and early atherosclerosis in the given population, and to find out the predictive power of preoperative vascular functional assessment in the prediction of perioperative cardiovascular events in the same population. We had selected patients who had at least two risk factors for endothelial dysfunction and were posted for elective non-cardiac surgical procedures via convenience sampling. Flow-mediated vasodilatation of the radial artery (FMD) and carotid intima-media thickness (CIMT) were measured on the previous day of surgery, while a fasting lipid profile was collected from the patients on the morning of the surgery. Endothelial dysfunction was defined as FMD<4.5%, while atherosclerosis was defined as CIMT>0.07 cm. Demographic details and baseline hemodynamic parameters of the patients were also noted preoperatively as well as intra-operatively, and patients were followed up for any major clinical adverse cardiovascular event post-operatively till they were discharged from the hospital. Results: It was found that the prevalence of endothelial dysfunction was 23%, while the prevalence of early atherosclerosis was 33% in our study population. However, it was found that FMD and CIMT did not correlate with each other significantly, nor did they correlate significantly with perioperative cardiovascular events. The risk factors of the patients also did not correlate with the FMD and CIMT values of the patients in which they were impaired. Moreover, they did not have any significant correlation with the perioperative events that occurred. Conclusion: The prevalence of endothelial dysfunction in our tertiary center was found to be 23%, and the prevalence of atherosclerosis was 33% in patients posted for elective non-cardiac surgery who had multiple risk factors. It was also found that non-invasive preoperative vascular assessment was not quite effective as hypothesized in predicting perioperative cardiovascular events.