Carotid ultrasound: prevention of heart disease and mortality on haemodialysis

Abstract

Cardiovascular disease and other complications of atherosclerosis are the most common cause of death in patients with chronic renal failure in maintenance hemodialysis (MHD). Carotid ultrasonography is a simple non-invasive tool to investigate the vascular system, by means of intima media thickness (IMT) measurement and carotid wall calcifications. To determine IMT and the presence of plaques, and their possible clinical relationships; finally we tried to investigate whether they would predict cardiovascular morbidity and mortality in patients in MHD. We studied 60 MHD patients (age 68 +/- 13 years, 48% male, 50% diabetics, time on MHD 32 +/- 11 months) and a control group of 274 people matched for age and sex. Follow-up period was 66 +/- 13 months. Demographic and clinical data, serum levels of homocysteine (tHcy), folic acid (FA) and B6 and B12 vitamins. IMT was measured by high-resolution B-mode ultrasonography. IMT was higher in MHD patients than in those in the control group (0.947 +/- 0.308 vs 0.619 +/- 0.176 mm; P < 0.001). IMT was related with age (r = 0.268; P = 0.038), diabetic (r = 0.650; P < 0.001) and hypertensive condition (r = 0.333; P = 0.012), but not wih lipids, tHcy or FA. Patients who suffered from coronary artery disease, peripheral artery disease or stroke had higher IMT than those without those events (1.156 +/- 0.371 vs 0.875 +/- 0.285 mm; P < 0.001; 1.205 +/- 0.374 vs 0.911 +/- 0.231 mm; P = 0.007; 1.195 +/- 0.264 vs 0.844 +/- 0.251; P < 0.001 respectively). Something similar occurred with the presence of plaques. During the follow-up period 36 patients died (60%), 67% of them due to cardiovascular causes. IMT was higher in patients who died than those who survived (1.020 +/- 0.264 vs 0.858 +/- 0.334 mm; P = 0.044). The survival rate during the observation period was significantly lower in the final IMT fourth (20%) than in the first (72%) (P = 0.014). The presence of carotid plaques was an independent predictor of cardiovascular mortality. These findings suggests that measurement of carotid IMT and the presence of wall plaques are useful tools to predict cardiovascular events and mortality in patients in MHD.