Preoperative white matter lesions are independent predictors of long-term survival after internal carotid endarterectomy

Background

Cerebral white matter lesions (WMLs) predict long-term survival of conservatively treated acute stroke patients with etiology other than carotid stenosis. In carotid endarterectomy patients, WMLs are associated with severe carotid stenosis and unstable plaques, with the risk of perioperative complications and with increased 30-day perioperative risk of death. However, no data exist on their effect on postoperative long-term survival, a factor important when considering the net benefit from carotid endarterectomy. Whether this effect is independent of classical risk factors and indications for surgery is not known either. We hypothesized that WMLs could be evaluated from preoperative routine computed tomography (CT) scans and are predictors of postoperative survival, independent of classical cardiovascular risk factors, indication category and degree of carotid stenosis.

Methods

A total of 353 of 481 (73.4%) consecutive patients subjected to carotid endarterectomy due to different indications, i.e. asymptomatic stenosis (n = 28, 7.9%), amaurosis fugax (n = 52, 14.7%), transient ischemic attack (n = 135, 38.2%) or ischemic stroke (n = 138, 39.1%), from prospective vascular registries during the years 2001-2010 with digital preoperative CT scans, were included in the study. WMLs were rated by a radiologist (Wahlund criteria) in a blinded fashion. Internal carotid artery (ICA) stenoses were angiographically graded (<50, 50-69, 70-99 and 100%). Odds ratios (ORs) and hazard ratios (HRs) are reported (ORs and HRs ≤1 indicate a beneficial effect). The median follow-up time was 67 months (interquartile range 45.5, range 0-129 months). Spearman's rho was used to estimate intraobserver agreement. Binary logistic regression was performed to analyze the association of risk factors with WMLs. Cox regression proportional hazards analysis was used to study the effect of different factors on survival.

Results

WML severity could be assessed with a substantial intraobserver agreement (Spearman's rho 0.843, p < 0.0001). Only age (OR 1.10, 95% CI 1.06-1.15; p < 0.0001 per year), degree of ipsilateral ICA stenosis (OR 2.22, 95% CI 1.08-4.55; p < 0.05 per stenosis grade) and indication category (OR 1.63, 95% CI 1.19-2.24; p < 0.01 per category) remained independently associated with WMLs. Age (HR 1.04, 95% CI 1.01-1.08; p < 0.05 per year), diabetes (HR 1.59, 95% CI 1.01-2.49; p < 0.05), peripheral arterial disease (HR 2.47, 95% CI 1.46-4.15; p < 0.01), degree of ipsilateral ICA stenosis (HR 2.56, 95% CI 1.12-5.87; p < 0.05 per stenosis grade) and WMLs (HR 3.83, 95% CI 1.17-12.5; p < 0.05) remained independently associated with increased long-term mortality.

Conclusions

WMLs in a preoperative CT scan provide a substantially reliable estimate of postoperative long-term survival of carotid endarterectomy patients independent of currently used criteria, i.e. cardiovascular risk factors, indication category and degree of ipsilateral ICA stenosis.

Lower limb amputations: differences between the genders and long-term survival

The purpose of the study was to evaluate possible differences between genders in amputation incidence, revascularization activity before and survival after amputation. This population-based study was carried out in a well-defined geographical area, where all vascular surgical consultations and reconstructions are performed in one university hospital. All amputations performed in the region during 1990 - 1999 were identified from the hospital central registers. According to patient's identity codes, the Cause of Death Registry of Statistics Finland provided death data. Amputation data were cross-linked with the local vascular registry using identity codes. Women were found to be 8 years older than men (p < 0.0001). Major amputations comprised 73.4% in males and 77.7% in females. The age-standardized amputation incidence among males was 338 and among females 226 (per 10(6) inhabitants/year) (p < 0.001). The most prominent difference was seen in amputations due to trauma, where the age-adjusted major amputation incidence was over three-fold among males compared to females. The proportion of patients who had undergone vascular procedure before amputation was 23% in both genders. Median survival after amputation was 943 days in men and 716 in women (p = 0.01). When the higher age of women was considered, there was no significant difference between the genders. Survival was poorer among diabetics in both genders and the difference was significant in males. The amputation incidence was found to be higher in men compared to women in all etiologic subgroups except malignant tumour. Almost one in 4 patients had undergone vascular surgical reconstruction before amputation in both genders. There was no significant difference between the genders in survival after amputation. Subjects with diabetes had a poorer survival after major amputation than those without diabetes.