Effect of nonoptimal imaging on the relationship between the measured degree of symptomatic carotid stenosis and risk of ischemic stroke.

BACKGROUND AND PURPOSE: Some recent studies of noninvasive carotid imaging have identified high rates of inappropriate decision-making about endarterectomy compared with conventional arterial angiography (CAA), but there is substantial inconsistency across the published literature. CAA is usually regarded as the gold standard for carotid imaging, partly because the degree of angiographic stenosis is a powerful predictor of ischemic stroke and hence of benefit from endarterectomy. However, there are very few published data on the extent to which predictive power varies with type of CAA or the number and quality of views of the stenosis obtained. METHODS: We analyzed measurements of stenosis made by 2 independent observers on 967 consecutive patients randomized to medial treatment alone in the European Carotid Surgery Trial (ECST). We determined prediction of 3-year risk of ipsilateral ischemic stroke (as a hazard ratio from a Cox model and as the area under a receiver operating characteristic curve [AUC]) in relation to the technique of angiography, the number and quality of views of the stenosis, and the use of 2 independent measurements. RESULTS: Using 2 independent measurements of stenosis increased predictive power slightly, but the effect was much smaller than that attributable to the type of CAA and the number of views of the stenosis. Prognostic value was greater in patients who had selective carotid injection CAA and at least biplane views (AUC, 0.75; 0.68 to 0.82) than in patients with only a single view or aortic arch injection CAA (AUC, 0.65; 0.56 to 0.73; P=0.03). CONCLUSIONS: The dependence of the prognostic value of CAA on the type of angiography and the number of views of the stenosis obtained has implications for the future development and validation of noninvasive methods of carotid imaging.

A systematic review of the associations between age and sex and the operative risks of carotid endarterectomy.

BACKGROUND: Randomized trials of carotid endarterectomy (CEA) for both symptomatic and asymptomatic carotid stenosis have demonstrated that benefit is decreased in women, due partly to a high operative risk, which is independent of age. However, it is uncertain whether these trial-based observations are generalisable to routine clinical practice. METHODS: We performed a systematic review of all publications reporting data on the association between age and/or sex and procedural risk of stroke and/or death following CEA from 1980 to 2004. RESULTS: 62 eligible papers reported relevant data. Females had a higher rate of operative stroke and death (25 studies, OR = 1.31, 95% CI = 1.17-1.47, p < 0.001) than males, but no increase in operative mortality (15 studies, OR = 1.05, 95% CI = 0.81-0.86, p = 0.78). Compared with younger patients, operative mortality was increased at > or =75 years (20 studies, OR = 1.36, 95% CI = 1.07-1.68, p = 0.02), at age > or =80 years (15 studies, OR = 1.80, 95% CI = 1.26-2.45, p < 0.001) and in older patients overall (35 studies, OR = 1.50, 95% CI = 1.26-1.78, p < 0.001). In contrast, risk of non-fatal stroke did not increase with age and so the combined perioperative risk was only slightly increased at age > or =75 years (21 studies, OR = 1.18, 95% CI = 0.94-1.44, p = 0.06), at age > or =80 years (10 studies, OR = 1.14, 95% CI = 0.92-1.36, p = 0.34) and in older patients overall (36 studies, OR = 1.17, 95% CI = 1.04-1.31, p = 0.01). CONCLUSIONS: The effects of age and sex on the operative risk of CEA in published case series are consistent with those observed in the trials. Operative risk of stroke is increased in women and operative mortality is increased in patients aged > or =75 years.

A systematic review of outcome following synchronous carotid endarterectomy and coronary artery bypass: influence of surgical and patient variables.

OBJECTIVES: Outcomes after synchronous carotid endarterectomy (CEA) plus coronary artery bypass (CABG) relative to surgical and patient based variables. DESIGN: Systematic review of 94 published series (7863 synchronous procedures). RESULTS: 11.5% of patients died or suffered a stroke/myocardial infarction in the peri-operative period (95% CI 10.1-12.9). The risk of death/stroke appeared to significantly diminish in studies published between 1993-2002, compared with 1972-1992 (7.2% (95% CI 6.5-9.1) versus 10.7% (95% CI 8.9-12.5), p = 0.03). However, increasing operative experience was not associated with significantly lower risks of death/stroke; (1-49 cases (9.6% (95% CI 7.5-11.8); 50-99 cases (9.1% (95% CI 6.4-11.8); 100+ cases (8.4% (95% CI 6.9-10.1) (p = 0.64)). Patients with severe bilateral carotid disease were significantly more likely to suffer death and/or stroke compared to patients with unilateral disease (odds ratio 2.5, 95% CI 1.4-5.0, p = 0.001). Similarly, patients with a prior history of stroke/transient ischaemic attack (TIA) were significantly more likely to suffer a further stroke than asymptomatic patients (odds ratio 1.8, 95% CI 1.1-2.8, p = 0.008). There was no difference in the risk of death/stroke relative to the timing of CEA (pre- versus on-cardiopulmonary bypass), but recent small studies indicate that improved outcomes might be achieved by performing CABG 'off-bypass'. CONCLUSIONS: Synchronous CEA + CABG is associated with a not insignificant cardiovascular risk. No comparable information is available for similar patients undergoing CABG without prophylactic CEA.

A systematic review of outcomes following staged and synchronous carotid endarterectomy and coronary artery bypass.

OBJECTIVES: to determine the overall cardiovascular risk for patients with combined cardiac and carotid artery disease undergoing synchronous coronary artery bypass (CABG) and carotid endarterectomy (CEA), staged CEA then CABG and reverse staged CABG then CEA. DESIGN: systematic review of 97 published studies following 8972 staged or synchronous operations. RESULTS: mortality was highest in patients undergoing synchronous CEA+CABG (4.6%, 95% CI 4.1-5.2). Reverse staged procedures (CABG-CEA) were associated with the highest risk of ipsilateral stroke (5.8%, 95% CI 0.0-14.3) and any stroke (6.3%, 95% CI 1.0-11.7). Peri-operative myocardial infarction (MI) was lowest following the reverse staged procedure (0.9%, 95% CI 0.5-1.4) and highest in patients undergoing staged CEA-CABG (6.5%, 95% CI 3.2-9.7). The risk of death+/-any stroke was highest in patients undergoing synchronous CEA+CABG (8.7%, 95% CI 7.7-9.8) and lowest following staged CEA-CABG (6.1%, 95% CI 2.9-9.3). The risk of death/stroke or MI was 11.5% (95% CI 10.1-12.9) following synchronous procedures versus 10.2% (95% CI 7.4-13.1) after staged CEA then CABG. CONCLUSIONS: 10-12% of patients undergoing staged or synchronous procedures suffered death or major cardiovascular morbidity (stroke, MI) within 30 days of surgery. Overall, there was no significant difference in outcomes for staged and synchronous procedures and no comparable data for patients with combined cardiac and carotid disease not undergoing staged or synchronous surgery.

The Queensland cholera incident of 1977. 2. The epidemiological investigation.

In 1977 the first case of cholera known to be contracted in Australia during the seventh pandemic occurred in southeastern Queensland. Toxigenic isolates of Vibrio cholerae, biotype eltor, serotype Inaba, phage-type 2, were obtained from the index case, a companion of the patient, the reticulated water supply of their place of residence, and a stretch of the neighbouring river that was being used to supplement fully treated water piped from Brisbane. Treatment of the auxiliary supply consisted solely of chlorination. A section of another river was later shown to contain V. cholerae. No source of pollution was identified for either river. From the persistence of the microorganism in the first river over a two-month period, despite increases in river flow following significant rainfall, it seems that the cholera vibrio can not only survive for a long period but can also grow in the river water. This strongly suggests that certain surface, and possibly subsurface, waters may serve as potential silent foci of V. cholerae. Hence the importance of providing bacteriologically safe water supplies, and the possible need to expand the definition of a 'cholera-receptive area'.