R. Cuming

Influence of patient-related variables on the outcome of carotid endarterectomy

PURPOSE Variability in outcome after carotid endarterectomy is well recognized. This study examines the importance of patient-related factors in determining outcome. METHODS Four hundred and sixty consecutive patients undergoing carotid endarterectomy for symptomatic severe (60% to 99%) internal carotid stenosis performed by one vascular surgeon have been studied prospectively. Patients were followed-up at 3, 6, 9, and 12 months and then yearly. Pre-, intra-, and perioperative details and follow-up information were entered on a database. RESULTS Multiple logistic regression identified a number of factors significantly associated with death and stroke. A history of crescendo transient ischemic attacks (TIAs) (p = 0.003, p = 0.0002) and being female (p = 0.03, p = 0.0001) were associated with both perioperative death and stroke within 30 days of operation, respectively. Deaths between 1 and 36 months were associated with ischemic heart disease (p = 0.03) and diabetes (p = 0.04), whereas stroke was associated with small internal carotid diameter (p = 0.02). The importance of symptoms at presentation on outcome was further emphasized by life-table analysis. In 98% of patients with amaurosis fugax, only 67% of those with crescendo TIAs were alive at 18 months (p < 0.01). The survival of patients with amaurosis was significantly better than those with TIAs (p < 0.01), transient stroke (p < 0.01), and progressive, stroke (p < 0.05). Similarly, postoperative stroke was significantly more common for patients with crescendo TIAs than those with amaurosis (p < 0.01), established stroke (p < 0.05), and TIA (p < 0.05). Transient stroke was associated with a poor outcome, with only 66% of patients being alive in 36 months and 14% having suffered a stroke (p < 0.05 compared with established stroke). CONCLUSION Presenting symptoms significantly predict outcome after carotid endarterectomy. This should be considered both in patient selection and comparison of patient series.

Clinical follow-up rather than duplex surveillance after carotid endarterectomy ☆ ☆☆

PURPOSE The value of duplex surveillance and the significance of contralateral carotid disease after endarterectomy have been assessed. METHODS Three hundred five patients were observed prospectively after carotid endarterectomy for a median time of 36 months (range, 6 to 96 months), with duplex surveillance performed at 1 day; 1 week; 3, 6, 9, and 12 months; and then each year after endarterectomy. RESULTS Thirty patients (10%) had ipsilateral symptoms (13 strokes, 17 transient ischemic attacks [TIAs]) at a median time of 6 months (range, 0 to 60 months). Life table analysis demonstrated that ipsilateral stroke was equally common for patients who had > or = 50% restenosis (3% at 36 months) and those who did not (6% at 36 months, p > 0.5). Twenty-three patients (8%) developed symptoms (stroke 5, TIA 14) attributable to the contralateral carotid artery at a median time of 9 months (range, 0 to 36 months) after endarterectomy. By life table analysis, 40% of patients with 70% to 99%, 6% with 50% to 69%, 1% with < 50% contralateral internal carotid stenosis, and 5% with contralateral carotid occlusion at the time of endarterectomy had a contralateral TIA in the 36 months after endarterectomy (p < 0.01). However, contralateral stroke was not significantly more common for patients with severe contralateral internal carotid stenosis demonstrated at the time of endarterectomy (< 50% stenosis, 0%; 50% to 69%, 3%; 70% to 99%, 7%; occlusion, 6% stroke rate at 36 months). Seven of the 32 patients who developed progression of contralateral disease had a TIA, compared with 11 of 227 patients who did not develop progression of contralateral disease (p < 0.01). None of the 12 patients who progressed from a < 70% to a 70% to 99% contralateral stenosis had a stroke. CONCLUSIONS After carotid endarterectomy restenosis is rarely associated with symptoms; contralateral stroke is rare and is not associated with progressive internal carotid artery disease suitable for endarterectomy. This study has shown no benefit from long-term duplex surveillance after carotid endarterectomy. Selective clinical follow-up of patients who have high-grade contralateral stenoses would appear more appropriate.

The Influence of Smoking and Lipids on Restenosis After Carotid Endarterectomy

Factors associated with restenosis were investigated in 107 patients undergoing carotid endarterectomy for symptomatic disease. The patients, 71 men and 36 women with mean age 68 +/- 8 years, were followed up for 1 year by serial Duplex scanning. Carotid restenosis of > or = 50% developed in 18 patients (17%), 11 men and seven women. Restenosis was not influenced by age, sex, diabetes or hypertension. Continuing smokers, serum cotinine > 200 nmol/l, had a significantly higher incidence of > or = 50% restenosis after 1 year (39%), compared with only 16% of non-smokers, p = 0.023. Restenosis > or = 50% also was associated significantly with below median body mass index (p = 0.027). Women undergoing carotid endarterectomy had higher levels of cholesterol (median 7.4 mmol/l) and apolipoprotein B (median 0.81 g/l) than men (median cholesterol 6.4 mmol/l, median apolipoprotein B 0.69 g/l), p < 0.01. For men only, restenosis of > or = 50% was associated with low levels of serum cholesterol (median 5.7 mmol/l), p = 0.002. For women cholesterol levels were higher (median 8.1 mmol/l) in those with > or = 50% restenosis. Smoking adversely influences early restenosis (1 year) after carotid endarterectomy. Hyperlipidaemia is not a risk factor for restenosis in men, but may be associated with restenosis in women.

Prevalence, progression and natural history of asymptomatic carotid stenosis: Is there a place for carotid endarterectomy?

The purpose of this study was to determine the prevalence, progression and prognosis of asymptomatic carotid artery stenosis in a population of 1198 patients with peripheral arterial disease (n = 986) or aortic aneurysm (n = 212), mean age 67.7 (S.D. = 10.0) years. Patients were recruited from 1985 to 1989 with annual assessment of carotid artery stenosis of over 50% using Doppler peak frequency analysis. Patients were followed up annually until 1990 or their first event, transient ischaemic attack (TIA), amaurosis fugax (AFx), stroke without antecedent TIA, or death (mean follow up 20 months). Life tables were used to determine risk of events in different patient groups. Only 164 (13.7%) patients had a stenosis of over 50% in either of the common or internal carotid arteries, disease was bilateral in 33 (2.8%) patients. A total of 33 patients (2.8%) had over 80% stenosis in common or internal carotid arteries. During follow up 37 (3.1%) patients developed a stenosis greater than 50%. Only 27 (2.3%) patients developed a stroke, 11 of which were fatal. A further 33 (2.8%) suffered a TIA or AFx and a total of 155 patients died during follow up. The total neurological event rate (TIA, AFx and stroke) was significantly associated with the presence of over 50% stenosis, [relative risk (RR) = 2.98, 95% confidence interval (95% C.I.) 1.68-5.29, p less than 0.001] and carotid bruit (RR = 1.16, 95% C.I. 1.23-3.81, p = 0.010). Although risk of stroke was higher in patients with a 50% stenosis, this failed to achieve statistical significance (RR = 1.78, 95% C.I. 0.66-4.80, p = 0.275).(ABSTRACT TRUNCATED AT 250 WORDS)

Outcome of selective patching following carotid endarterectomy

OBJECTIVES Routine patch angioplasty has been advocated following carotid endarterectomy but patching can be associated with complications. This study assesses the effect of a selective patching policy based on distal internal carotid diameter on the rate of restenosis and outcome following carotid endarterectomy. DESIGN, MATERIAL AND METHODS A consecutive series of 213 patients underwent carotid endarterectomy performed by one surgeon. Preoperative carotid dimensions were measured intraoperatively using calipers. Following endarterectomy a 5mm Dacron patch was selectively employed if the distal internal carotid was 5mm or less (group 1, 95 patients) or 6mm or less (group 2, 118 patients). Patients underwent colour-coded Duplex scanning at 24 h, 1 week, 3, 6, 9, and 12 months, and yearly following this. RESULTS Overall 27 restenoses (5 residual) of 50% or greater and two occlusions developed. Patching was performed in 47% of group 1 and 61% of group 2 arteries. In group 1 14% of patched compared with 24% of non-patched arteries developed restenosis at 24 months (p=0.4). In group 2 13% of patched compared to 11% of non-patched arteries developed restenosis at 12 months (p>0.5). Stroke rate at 24 months were similar for patched and non-patched patients in groups 1 (p>0.5) and 2 (p=0.4). CONCLUSIONS This study suggests that patch angioplasty of larger carotid arteries may be unnecessary. Randomisation of larger arteries between patch and primary closure would be required to confirm this.

Duplex imaging findings predict stenosis after carotid endarterectomy

PURPOSE This study was performed to determine whether early duplex findings predicted restenosis after carotid endarterectomy. METHODS One hundred ninety-two symptomatic patients who underwent carotid endarterectomy were studied with color duplex imaging at 1 day and 1 week after surgery to identify minor residual disease (causing < 50% stenosis), arterial kinking, and suture stricture, and to measure the external and luminal diameters of the carotid bulb and distal internal carotid artery. Patients were then observed prospectively with duplex surveillance for a median of 24 months to identify > 50% restenosis. RESULTS Twenty-five stenoses > 50% of the operated carotid artery (13%) were identified, four at 1 day (residual) and 21 at a median follow-up of 6 months (restenosis). On multiple logistic regression analysis, > 50% restenosis was found to be associated with minor day-1 residual stenosis (p = 0.01) and with small luminal diameter of the distal internal carotid artery (p = 0.03) as measured 1 week after carotid endarterectomy. Life table analysis showed restenosis at 24 months to be more common for patients with below-median than patients with above-median carotid bulb external diameter (18% vs 5%, respectively; p = 0.01). CONCLUSIONS Duplex scanning within a week of carotid endarterectomy identifies > 50% residual stenosis, in addition to minor residual 25% to 50% stenosis and small carotid dimensions, which are good predictors of > 50% restenosis at 6 months.

Urgent carotid surgery for high risk patients

Carotid surgery was performed urgently on 22 occasions out of 300 (7%). Of 15 patients with progressing stroke, in all, progression of stroke was arrested. Six patients recovered virtually completely and eight had improving neurological deficit after surgery, i.e. 14 of 15 (93%) benefitted. The other patient had arrest of stroke for a week and then suffered ipsilateral stroke. Of the seven patients operated upon for crescendo transient ischaemic attacks, five had no deficit after surgery or further attacks. The sixth patient had no further attacks but was found to have a tiny, neurological deficit. In these six patients (87%), surgery was greatly beneficial. The remaining patient had a fatal stroke following operation.

The use of Duplex scanning to diagnose perioperative carotid occlusions

Perioperative stroke following carotid endarterectomy is reported to occur in 3-20% of patients and may be associated with spontaneous development of thrombus at the operation site or technical imperfections. In 118 consecutive patients, duplex scanning performed immediately before anaesthesia was used to confirm that all high grade carotid stenoses had not progressed to occlusion since the arteriogram. A new technique at completion, using subcuticular prolene sutures for the skin and a plastic dressing for the wound, permitted immediate postoperative assessment by duplex scanning if necessary. Of the 118 patients, symptoms of neurological instability developed in 4 (3.4%) in the first 6 hours after surgery. At duplex scanning, developing thrombus was demonstrated in three of these patients. Arterial thrombus was removed at reoperation and all three patients recovered with no neurological deficit. The fourth patient had occluded the contralateral carotid artery, developed a major stroke and was not considered for re-exploration. Duplex scanning provides accurate diagnostic information in selecting patients for urgent re-exploration, reducing the 24 h stroke rate to 0.8% in this series.

The Reproducibility of Colour-coded Duplex Scanning in Measuring Arterial Wall Dimensions

Intimal hyperplasia continues to be a major problem following vascular surgery but experimental evidence suggests that it can be reduced pharmacologically. For clinical studies an accurate, reproducible and non-invasive image of the intima and lumen is required. We have assessed the value of the Acuson 128 Colour Duplex for such studies. Ten patients had their common femoral arteries scanned at a fixed point by two experienced observers on two separate occasions. External vessel diameter, luminal diameter and internal diameter (i.e. the diameter within the internal elastic lamina) were measured in both longitudinal and cross-sectional views. Cross-sectional area and degree of stenosis were all measured and all parameters expressed as limits of agreement. The mean external diameter of the common femoral arteries was 10.5 +/- 1.6 mm. Measurements in the longitudinal view were highly reproducible with limits of agreement ranging from -0.67 - +0.25 mm (internal diameter) to -1.49 - +1.31 mm (luminal diameter). In order to detect a meaningful change in longitudinal external diameter a real difference of 0.86 mm is required representing a change of less than 10%. Cross-sectional diameter measurements were similarly reproducible (-0.73 - +0.47 mm to -1.97 - +1.79 mm). However, cross-sectional area measurements had a wide variation so that the error in degree of stenosis was -25.4 - +30.2%. Thus, duplex ultrasound reproducibly images the layers of the arterial wall. Prospective studies of intimal hyperplasia are feasible but must be based on longitudinal and cross-sectional diameters rather than cross-sectional areas.