Impact of diabetes mellitus on early outcome of carotid endarterectomy

Background: Diabetes mellitus increases the risk of ischaemic stroke in the general population but its impact on early outcome after the carotid endarterectomy (CEA) is controversial with conflicting results.

Patients and methods: This prospective study includes 902 consecutive CEAs. Patients were divided into non-diabetic and diabetic groups and subsequently analysed. Early outcomes in terms of 30-day stroke and death rates were then analysed and compared.

Results: There were 606 non-diabetic patients. Among 296 diabetic patients, 83 were insulin-dependent. The cumulative TIA/stroke rate was statistically higher in the diabetic group (2.6 vs. 5.7 %, P = 0.02). Stroke was more frequent in the diabetic group (2.0 vs. 4.4 %, P = 0.04) comparedto TIA (0.7 vs. 1.4 %, P = 0.45). Mortality was statistically more frequent in diabetic patients (0.2 vs. 1.7 %, P = 0.01). The 30-day stroke/death rate (2.6 vs. 5.7 %, P = 0.02) was also statistically higher in the diabetic group. Factors that were identified to increase risk of death and stroke in multivariate analysis were: use of insulin for blood glucose control (OR = 2.47, 95 % CI 1.61-4.68, P = 0.01), higher low-density lipoprotein cholesterol value (OR = 1.52, 95 % CI 1.15-2.22, P < 0.01), presence of coronary disease (OR = 2.04, 95 % CI 1.40-3.31, P = 0.03), peripheral artery disease (OR = 2.14, 95 % CI 1.34-3.65, P = 0.02), complicated plaque (OR = 1.77, 95 % CI 1.11-3.68, P = 0.03), contralateral carotid artery occlusion (OR = 2.37, 95 % CI 1.25-4.74, P = 0.02), shunt use (OR = 3.46, 95 % CI 1.18-7.10, P < 0.01), and among diabetic patients higher HbA1c levels (OR = 1.28, 95 % CI 1.05-1.66, P = 0.03). Clamp toleration was associated with lower risk of death and stroke rates (OR = 0.43, 95 % CI 0.23-0.76, P < 0.01).

Conclusions: In our study, perioperative neurological complications and mortality were statistically higher in diabetic patients compared to non-diabetic patients during CEA. Further research will have to show whether other treatment modalities of carotid artery stenosis and better glycaemia and dyslipidaemia controlling in diabetics can reduce this risk.