Long-term results after carotid artery surgery

SUBOPTIMAL PREVENTIVE PRACTICES IN PATIENTS WITH CAROTID AND PERIPHERAL VASCULAR OCCLUSIVE DISEASE IN A TERTIARY REFERRAL SETTING

BACKGROUND

Effective strategies for the prevention of adverse vascular events in patients with atherosclerotic vascular disease include smoking cessation, platelet inhibition, antihypertensives, hypoglycaemic and cholesterol lowering agents. The current literature suggests that these practices are suboptimal in patients with peripheral vascular disease (PVD). This study aims to examine and compare the use of preventive therapy in patients admitted for interventions related to peripheral and carotid atherosclerotic occlusive disease.

METHODS

All inpatients undergoing diagnostic or therapeutic procedures for occlusive disease of the lower limb and carotid artery at Royal Perth Hospital, Western Australia, between January 2000 and December 2000 were included in the study. Their medical charts were reviewed to measure the prevalence of the use of antithrombotic, antihypertensive and cholesterol-lowering therapies.

RESULTS

Medical charts of 256 patients (97%) were reviewed during the study period. Carotid related procedures accounted for 26% of the sample. Overall, 80% were prescribed antithrombotic (antiplatelet or anticoagulation) therapy at the time of discharge. In the carotid group, 97% were on some form of antithrombotic therapy as opposed to 75% in the PVD group. Antihypertensive and cholesterol lowering therapies were used in 82% and 63%, respectively, of the carotid group vs 68% and 36% in the PVD group. Rates of preventive practices were lowest in the subgroup of PVD patients without a history of coronary or cerebrovascular disease.

CONCLUSIONS

Preventive therapies are under utilized in patients with PVD. Effective strategies need to be developed to encourage the use of these adjunctive therapies in the long-term management of vascular patients.

Surgical therapy for coronary artery disease among patients with combined coronary artery and peripheral vascular disease

BACKGROUND

Among patients with combined coronary artery and peripheral vascular disease, long-term benefits of surgical therapy compared with medical therapy for coronary artery disease are unknown.

METHODS AND RESULTS

Using prospectively collected data from the Coronary Artery Surgery Study registry, we performed a retrospective cohort analysis of 1834 patients (mean age, 56 years; 20% women) with both coronary artery and peripheral vascular disease and evaluated their long-term outcomes. Of these patients, 986 received (nonrandomly) coronary artery bypass graft surgery, and 848 were treated medically. Perioperative mortality was 4.2% (2.9% in the absence of peripheral vascular disease; P = .02). In a mean follow-up period of 10.4 years, 1100 deaths occurred (80% due to cardiovascular causes). For the surgical group, 4-, 8-, 12-, and 16-year estimated probabilities of survival were 88%, 72%, 55%, and 41%, respectively, and 73%, 57%, 44%, and 34%, respectively, for the medical group (P < .0001). Multivariate analysis demonstrated that type of therapy was independently associated with survival (P = .0001; chi 2 = 15.34). Subgroup analysis suggested that benefits of surgical treatment on survival were limited to patients with three-vessel coronary artery disease and were inversely related to ejection fraction. Survival free of death or myocardial infarction was also significantly better among the surgical group. Type of therapy was significantly associated with occurrence of late events (P = .01; chi 2 = 6.55). Subgroup analysis again demonstrated that beneficial effects of surgery were limited to patients with three-vessel coronary artery disease and were inversely related to ejection fraction.

CONCLUSIONS

Surgical treatment provides long-term benefit for certain subgroups of patients with combined coronary artery and peripheral arterial vascular disease.

Coronary artery disease in patients with peripheral vascular disease

For patients requiring peripheral vascular surgery, coronary artery disease is the major determinant of perioperative mortality and long-term survival. The management of coronary artery disease in these patients is controversial as no randomized blinded prospective studies have been conducted. Data on the prevalence, diagnosis and management are reviewed.

Does low-dose acetylsalicylic acid prevent stroke after carotid surgery? A double-blind, placebo-controlled randomized trial

BACKGROUND AND PURPOSE

The aim of this randomized double-blind, placebo-controlled trial was to evaluate whether neurological deficits could be prevented with low-dose acetylsalicylic acid (ASA) as an adjunct to carotid endarterectomy.

METHODS

A total of 232 patients were randomized to two groups, 75 mg/d ASA starting preoperatively and continued for 6 months (n = 117) or placebo (identical tablets) (n = 115). The patients were followed up regularly for 1 year.

RESULTS

The groups were well matched regarding laboratory data and indication for operation. The number of patients with intraoperative or postoperative stroke without complete recovery within 1 week were 0 and 2 at 30 days and 6 months, respectively, in the ASA group, compared with 7 and 11 in the placebo group (P = .01). Including all neurological events within 6 months, this was found in 15 patients in the ASA group compared with 24 in the placebo group (P = .12). Mortality was 0.8% and 3.4% at 30 days and 6 months, respectively, in the ASA group. In the placebo group, the corresponding figures were 4.3% and 6.0%, respectively (P = .12). The intraoperative bleeding did not differ between the groups nor did the number of reoperations due to bleeding or other complications related to pharmacology.

CONCLUSIONS

This study indicates that low-dose ASA (75 mg/d) reduces the number of postoperative strokes without complete recovery within 1 week. Overall neurological events are insignificantly reduced, as also mortality. The use of low-dose ASA (75 mg) seems safe and effective in reducing cerebrovascular events after carotid endarterectomy.

Natural history of abdominal aortic aneurysm detected by screening

A group of 88 patients with abdominal aortic dilation found in four ultrasonographic screening studies was followed prospectively by repeated ultrasonography. The initial aortic diameter ranged between 18 and 70 mm. In 19 patients (22 per cent) the aortic diameter exceeded 39 mm. The mean (s.e.m.) annual expansion rate of dilatations < 40 mm in diameter was 0.8 (1.2) mm; among those > or = 40 mm it was 3.3 (1.2) mm. The expansion rate increased with increasing initial diameter. Thirty-eight patients died; the overall mortality rate in the group was high in comparison with an age- and sex-matched population. One patient died after elective aneurysm surgery but none died from a ruptured aneurysm. In conclusion, in about 80 per cent of dilatations found in screening studies the aortic diameter was < 40 mm, with a low risk of rupture. One annual rescanning of an aneurysm < 35 mm in diameter is sufficient; a high overall mortality rate must be expected.

Natural history of patients with unoperated atherosclerotic carotid artery disease--results from a retrospective study

The natural history of carotid artery disease was studied in a retrospective study of 609 angiograms performed during 1969-1979 on patients who had subsequently not been operated on. The indication for angiography differed, but was aimed at clarifying suspected cerebrovascular events. 578 patients could be followed-up after a median time of 10.4 years (0-22). The median survival time after angiography was 9.7 years for the 355 men and 12.8 years for the 223 women (p = 0.0099). Internal carotid stenosis of > 50% was seen in 9.0% (bilaterally in 2.2%), a stenosis > 75% in 4.5% (bilaterally in 0.9%) and occlusion in 9% (bilaterally in 0.7%). Ulceration was present in 10.7% (bilaterally in 1.6%). 26.5% of the patients had a cerebrovascular event during follow-up, of which 31.4% had transient ischaemic attack or amaurosis fugax. Survival was not influenced by the degree of stenosis, but presence of arteriosclerotic carotid artery disease significantly reduced the median survival time from 11 to 3 years. The main cause of death for men was myocardial infarction (27.7%) and for women a cerebrovascular event (27.8%), a significant difference. From this study, in selected patients it can be concluded that the annual frequency of cerebrovascular events was low, approaching frequencies reported in asymptomatic patients. The cause of death differed between men and women, with more cardiac deaths among men and more cerebrovascular deaths among women.

Evaluation and management of patients with both peripheral vascular and coronary artery disease

The prevalence of serious angiographic coronary artery disease ranges from 37% to 78% in patients undergoing operation for peripheral vascular disease. Clinical studies have demonstrated that cardiac outcome after peripheral vascular surgery is not adequately predicted by the standard criteria of history, physical findings and rest electrocardiogram. An adequate exercise work load, left ventricular function and thallium redistribution have proved important in perioperative risk stratification. The choice of a perioperative functional cardiac test depends on patient-related factors and the nature of the peripheral vascular operation. Although procedures involving aortic cross-clamping exert a greater hemodynamic stress than do carotid endarterectomy and femoral popliteal surgery, late cardiac morbidity and mortality are significant in all patients with atherosclerotic disease. The decision to proceed with preoperative coronary angiography and myocardial revascularization should be based primarily on indications independent of the peripheral vascular procedure. However, peripheral vascular surgery may influence the timing of myocardial revascularization. Patients with high risk or unstable coronary artery disease may benefit from preoperative coronary revascularization, although this hypothesis remains unproved. In all patients, careful monitoring during and after operation is essential. All patients with peripheral vascular disease should be considered to be at lifelong risk for fatal and nonfatal cardiac events and should undergo appropriate clinical and laboratory evaluation and be treated accordingly.

Neurosurgical experience with carotid endarterectomy: a 12-year study

In the 13-year period from 1975 to 1988, 91 carotid endarterectomies were performed on 83 patients in a neurosurgical unit. Sixty-seven of these patients had continued to have symptoms after the best medical treatment. Seventy-one presented with transient ischaemic attacks (TIAs), nine with TIA and minor completed stroke (MCS), and three with MCS alone. Follow-up ranged from 8 months to 12 years with a mean of 5.5 years. Within the follow-up period, including operative complications, four deaths of cerebral origin (4.8%) and three major cerebral events (3.6%) occurred--an annual stroke morbidity and mortality rate of less than 1.5%, which compares favourably with a minimum stroke risk of 5% per annum for the first 3 years following a TIA and 3% for subsequent years. The annual stroke and/or vascular death rate including myocardial infarction was 3.5% compared to an expected stroke and/or vascular death rate of 7.4%. It appears that carotid endarterectomy is a useful adjunct to medical therapy. Myocardial ischaemia is the major cause of death in the follow-up period in this group of patients. It is suggested that patients with TIAs and MCS should be investigated, and those who do not respond to medical therapy should be identified for carotid endarterectomy.

Antiplatelet therapy following carotid bifurcation endarterectomy. Evaluation of a controlled clinical trial. Prognostic significance of histologic plaque examination on behalf of survival

To determine whether antiplatelet therapy following carotid bifurcation endarterectomy influences postoperative survival and whether signs of progression in the plaques harvested at the time of surgery might be a prognostic indicator, a controlled clinical trial was undertaken. During 1982 to 1985, 66 patients were recruited, operated on (carotid endarterectomy) and assigned, using the method of adaptive randomisation to the therapy group (n = 32) receiving 1.0 g acetylsalicylic acid (ASA) per day, starting day two prior to surgery, or to the control group (n = 34), which remained without antiplatelet medication. The plaques harvested at the time of surgery were processed using standard histopathological methods and examined "blindly" by light microscopy for signs of arterio-sclerotic progression. The final endpoint was patient survival. The last assessment of the participants survival status was done by June 1989. During follow-up, 20 patients died, six in the treatment group and 14 in the untreated group, the difference being statistically significant (P less than 0.013 Breslow, P less than 0.029 Mantel). In 27 instances the histo-pathological examination showed signs of progression. In this subgroup ASA yielded a significant prolongation of patient survival (P less than 0.017 Breslow, P less than 0.048 Mantel). In the remaining patients no signs of cellular infiltration were evident and no influence of ASA on patient survival was demonstrable (P less than 0.503 Breslow, P less than 0.390 Mantel).

Antiplatelet treatment prolongs survival after carotid bifurcation endarterectomy. Analysis of the clinical series followed by a controlled trial

To examine the role of antiplatelet drugs in the secondary prevention of arteriosclerotic arterial disease following carotid endarterectomy, a clinical series (n = 252) was analyzed. Based on these results a prospective randomized trial was initiated, comparing the effect of antiplatelet drugs (acetyl-salicylic acid [ASA] 1000 mg/day) versus untreated controls. In both investigations patient survival was the primary end point. A cardiac risk (n = 91) implied a significant reduction in patient survival (p less than 0.019 Breslow, p less than 0.052 Mantel). Antiaggregating drugs prolonged survival in the collective series (p less than 0.0001 Breslow, p less than 0.0002 Mantel) and in the subgroup of patients with cardiac risk (p less than 0.014 Breslow, p less than 0.020 Mantel) as well. In the prospective trial 66 patients were recruited, receiving ASA (n = 32) versus no therapy (n = 34). During follow-up 15 patients died, 4 in the treatment, and 11 in the control group. Between both groups there was a significant difference in the probability of survival (p less than 0.021 Breslow, p less than 0.048 Mantel).

Local versus general anaesthesia in carotid surgery. A prospective, randomised study

A randomised, prospective study was performed to compare local (LA) and general anaesthesia (GA) in carotid surgery with special emphasis on complications and the need for intra-operative shunting. Fifty-six patients were randomised to LA and 55 to GA. Eight patients in the LA group required a GA for various reasons. During the same period 14 patients were not randomised. Seven perioperative neurological deficits occurred (5.6%), four in the LA group, two in the GA group, and one in the non-randomised group (NS). Selective shunting was used, in the Ga group according to stump pressure or in cases with a previous stroke and in the LA group according to the appearance of neurological symptoms. In the GA group 25 patients were shunted and in the LA group five patients (P less than 0.001) needed a shunt. If strict pressure criteria for shunting had been used in the LA patients, ten would have been shunted and three of the patients who developed symptoms during clamping would not have been shunted. During surgery the highest recorded systolic pressure was significantly higher in the LA group (210 mmHg versus 173 mmHg, P less than 0.001). LA for carotid endarterectomy is comparable with general anaesthesia regarding peroperative complications but produces significantly higher blood pressures than general anaesthesia. On the other hand it allows the possibility of neurologic monitoring of the patient and leads to significantly less use of an intra-operative shunt.

Risk factors in carotid artery surgery: an evaluation of 414 operations

Four hundred and fourteen carotid reconstructions performed on 352 patients during the years 1971-82 were analysed retrospectively. Fifty-eight percent of the patients were operated on because of hemispheric transient ischaemic attacks (TIA). Twenty-eight percent had suffered a stroke before surgery. The overall combined mortality and morbidity was 7.7%. The procedure mortality was 2.9% with a slightly higher mortality i.e. 5.9% in the stroke group although not significantly higher than among non-stroke patients with a mortality of 1.4%. Patients of more than 70-years had a significantly higher operative mortality (11.1%) than the rest of the patients (1.7%). Non-fatal strokes occurred in 20 patients (4.8%). No correlation was found with the degree of stenosis of the contralateral artery.