Impact of elevated perioperative fasting blood glucose on carotid artery stenting outcomes

Background Carotid artery stenting (CAS) for high-risk individuals is accepted practice. An impaired fasting hyperglycemia (IFG) is often associated with poor procedural outcomes after other percutaneous procedures. The clinical outcomes of CAS for patients with elevated fasting blood sugar (FBS) are not well defined.

Methods A database of patients undergoing CAS was sampled from 2000 to 2009. An IFG was defined as plasma glucose >110 mg/dL. Life table analyses were performed to assess time-dependent outcome differences between those patients with and without IFG. The outcomes of freedom from restenosis, occlusion, death, recurrent symptoms, and neurologic event were calculated. Cox proportional hazard analysis or Fisher's exact test was performed to identify factors associated with outcomes.

Results During the study period 322 patients underwent 345 CAS procedures. The mean follow-up was 4.6 years. A total of 196 patients (61%) were male. The indications for CAS were neurologic symptoms in high-risk patients in 23% and asymptomatic high-risk in the remainder. Fifty-nine percent had an IFG but only 30% had a history of diabetes mellitus (DM). Patients with an IFG were more likely to suffer a major adverse event (MAE; death, myocardial infarction, stroke; 12% vs. 26%, ≤ 110 vs. > 110, respectively, at 5 years, P = 0.021 by chi-squared analysis) in the 90-day perioperative period. By life table analysis, there were no differences between normal and IFG patients with regards to freedom from occlusion or target vessel revascularization. The long-term MAE rate was significantly worse in patients with an IFG, driven by decreased survival and stroke rates. Patients carrying the diagnosis of DM had equivalent outcomes to non-DM patients (67 ± 5% vs. 62 ± 7%, ≤110 vs. >110, respectively, at 5 years, P = 0.84). The presence of metabolic syndrome and/or the combination of diabetes and metabolic syndrome in the IFG group were drivers of increasing poor MAE rates.

Conclusions Patients with IFG undergoing CAS are at a greater risk for periprocedural morbidity and worse MAE in both the short and long term. The diagnosis of DM does not have a similar impact on outcomes. A current IFG, as opposed to a history of DM, should be considered an important risk factor when determining the suitability for CAS.