Myocardial revascularization and carotid endarterectomy: a combined approach

The approach to the patient with combined carotid and coronary artery occlusive disease has been evolving since corornary bypass procedures became feasible. When neurological and cardiac symptoms are remote, sequential procedures are adequate. Neurological symptoms or severe carotid stenoses (or both) appearing simultaneously with symptoms of myocardial ischemia present a more difficult problem. Simultaneous operation has been performed in 16 patients with 1 early death (low output) and 2 cerebral complications (1 patient with residual hand weakness and 1 without neurological risidua). The morbidity and mortality seemed unrelated to the fact that procedures were done at one operation. Therapy, however, must be tailored to the individual patient.     

Carotid endarterectomy: a perspective

Carotid endarterectomies have been performed for over a decade now. To review the knowledge derived from this surgical experience, i studied 18 reports on the subject, giving attention to four specific phases of patient care: the diagnostic, preoperative, intraoperative, and postoperative periods. Emphasis was placed on studying the causes of postoperative morbidity and mortality and how they are approached through radiologic, surgical, and medical technics.     

Carotid endarterectomy with shortened hospital stay

OBJECTIVE: To review the outcome of a consecutive series of patients undergoing carotid endarterectomy with a focus on length of stay. DESIGN: Retrospective case review. SETTING: Six hundred-bed community hospital. PATIENTS: During a 40-month period, we performed 266 carotid endarterectomies. Ages of patients ranged from 49 to 91 years (mean, 71.2 years). Seventy-two percent were hypertensive, 55% were smokers, 24% were diabetic, and 22% had symptomatic heart disease. Indications for operation included asymptomatic stenosis in 48% of patients, transient ischemia attack in 23%, stroke in 24%, and nonhemispheric symptoms in 5%. OUTCOME MEASURES: Perioperative complications and conditions precluding early hospital discharge were noted. In patients discharged within 48 hours of operation, problems requiring readmission within 30 days were recorded. RESULTS: Five patients (1.9%) experienced perioperative strokes, of which three were permanent and two temporary. There was one perioperative death. Hospital stays ranged from 1 to 9 days (mean 1.7 days). Sixty-three percent of the patients were discharged within 24 hours and 88% within 48 hours of operation. Patients staying in the hospital more than 48 hours were significantly older (P = .008). Other factors did not correlate with length of stay. Readmission was required in five patients. CONCLUSIONS: Patients having an uneventful course following carotid endarterectomy may be safely discharged within 48 hours of operation. Complications occurring after this time are infrequent and often unpredictable. It is unlikely that lengthening patient stay would decrease or eliminate these complications.     

Propranolol therapy in patients undergoing myocardial revascularization

The records of 185 consecutive patients having myocardial revascularization were reviewed with regard to preoperative administration of propranolol and intraoperative or postoperative complications. Tachycardia and hypertension before cardiopulmonary bypass were slightly more common in patients never taking propranolol or those who had discontinued it for more than 48 hours before operation. There was no statistically significant difference in the incidence of postbypass hypotension among patients who took propranolol within 24 hours of operation, those who discontinued it more than 24 hours before operation, and those who never took the drug. Operative mortality was not significantly different among patients who received propranolol within 48 hours of operation (3%), those who never took it and those who discontinued it more than 48 hours before operation (4%). Early in the series, five patients had an acute myocardial infarction within 48 hours after routine preoperative withdrawal of propranolol. Because complete withdrawal of propranolol in patients with unstable angina pectoris may lead to acute myocardial infarction, we recommend gradual withdrawal of the drug during 48 hours before operation. If this is not possible because anginal pain recurs or intensifies, then reduced doses may be given safely up to 10 hours before revascularization, provided that the patient is a satisfactory candidate for bypass and that adequate myocardial revascularization can be accomplished.     

Carotid endarterectomy for asymptomatic carotid artery stenosis: patients with severe bilateral disease a high risk subgroup

Carotid endarterectomy if advised for asymptomatic disease must be associated with a low peri-operative morbidity and mortality and satisfactory long-term results. Over a 12 year period between 1978-1989 181 carotid endarterectomies were performed on 163 patients with asymptomatic carotid artery stenosis. There were 112 males and 51 females with a mean age of 64.9 years. All patients had a high-grade lesion (> 70% stenosis). The combined operative mortality and stroke rate was 2.8%. On long-term follow up six patients suffered a stroke. Only one patient however sustained a stroke in the same territory as the previously operated carotid artery. Four years following surgery 78% of patients were alive. Carotid restenosis or occlusion occurred in 8.3% of the remaining patients, all of whom were asymptomatic. All the immediate postoperative strokes occurred in patients with severe bilateral carotid artery disease. These patients with severe bilateral disease appear to constitute a high risk sub-group for peri-operative stroke. The role of 'normal pressure-hyperperfusion breakthrough' syndrome as the presumed aetiology of two of the postoperative cerebral haemorrhages is discussed.     

Carotid endarterectomy for asymptomatic patients. Assessing results of a quantitative synthesis

Carotid endarterectomy (CE) surgery for asymptomatic patients remains controversial despite hundreds of published studies and recent randomized trials. Safety and efficacy are assessed using a quantitative synthesis method derived from meta-analysis and a "critical multiplist" inference approach. In addition, multivariate analyses reveal that use of a surgical shunt could further improve CE outcomes. Methods are examined for both their "confirmatory" and "exploratory" value.     

Carotid endarterectomy for asymptomatic carotid stenosis: a meta-analysis

OBJECTIVE: To assess the value of carotid endarterectomy for prevention of stroke in patients with asymptomatic carotid stenosis. DESIGN: Systematic review and meta-analysis of randomised controlled trials in patients with asymptomatic carotid stenosis in which subjects were allocated to carotid endarterectomy or to medical treatment alone. SUBJECTS: Five trials enrolled 2440 patients with stenosis >/ 50%. MAIN OUTCOME MEASURES: Stroke ipsilateral to the stenosis, all strokes, and perioperative complications (stroke or death). RESULTS: In patients who underwent carotid endarterectomy (n=1215) there was a significant reduction in the odds of ipsilateral stroke plus perioperative stroke or death (odds ratio 0.62; 95% confidence interval 0.44 to 0.86), corresponding to a 2% absolute risk reduction over about 3.1 years. The prevalence of stroke in any location was also reduced (0.68; 0.51 to 0.9) in patients undergoing carotid endarterectomy. During the immediate postoperative period there was an increased prevalence of stroke or death among such patients (4.51; 2.36 to 8.64). CONCLUSION: Carotid endarterectomy in patients with asymptomatic carotid stenosis unequivocally reduces the incidence of ipsilateral stroke, though the absolute benefit is relatively small. Given the modest benefit of surgery for unselected patients with asymptomatic carotid artery stenosis carotid endarterectomy cannot be routinely recommended for these patients pending reliable identification of high risk subgroups, and medical management is a sensible alternative for most patients.     

The behavior of late potentials in myocardial infarct patients undergoing myocardial revascularization

A novel 30 kb deletion of the beta-globin gene cluster associated with the phenotype of hereditary persistence of fetal hemoglobin (HPFH) is described in two unrelated individuals of Vietnamese background. The Vietnamese G gamma A gamma HPFH deletion has a unique 5' breakpoint 3.5 kb downstream of the delta-globin gene. The 3' breakpoint lies approximately 8 kb upstream from the HPFH-3 breakpoint (Henthorn et al., 1986) and in the region of the 3' breakpoints of HPFH-4 (Saglio et al., 1986), German and Belgian G gamma+ (A gamma delta beta)zero-thalassemias (Anagnou et al., 1988; Losekoot et al., 1991). Characterisation of the 3' breakpoint in the present study has enabled more precise localisation of other deletion breakpoints at this locus. Further evidence is provided that the 3' breakpoint region contains functionally important sequences and that the juxtaposition of these sequences to the gamma-globin genes is a significant factor in the increased fetal hemoglobin levels.     

Experience with fifty repeat procedures for myocardial revascularization

Fifty coronary reoperations were performed in 49 patients. The reasons for the operations were occluded or stenotic grafts in 23 patients, an inadequate first operation in 13, progression of coronary atherosclerosis in 3, and combinations of these reasons in 11. Mediastinal adhesions made the operations difficult and produced hazards. Six patients died from the operation. Seven surgical mishaps occurred, including damage to five functioning grafts from the previous operation and laceration of two ventricles. Nine patients had less than complete operations because angiographically demonstrated targets could not be found. Repeat angiography was performed on 9 of the surviving patients. Ten of the 14 new or revised grafts were found to be functioning. Although a repeat operation is more difficult technically and carries additional risks as compared with a first operation, the indications are thought to be the same for both first and secondary revascularization procedures. The increased risks of the repeat operations are compelling arguments to strive for complete revascularization at an initial operation in order to avoid the necessity of the second one.     

Carotid endarterectomy and abdominal aoritc aneurysm repair: are these reasonable treatments for patients over age 80?

Due to the aging of America, increased numbers of very elderly patients require peripheral vascular surgery. From April 1980 to November 1997, 191 patients age 80 years or older had carotid endarterectomy (CEA) and/or abdominal aortic aneurysm (AAA) repair at Loma Linda University Medical Center. The total perioperative stroke and death rate in the CEA group was 2.9 per cent. Mean postoperative cumulative survival in this group was 8.4 years. The cumulative stroke-free survival rate was 95.5 per cent for all yearly postoperative intervals up to 12 years. The perioperative mortality rate was 10.7 per cent in the nonruptured AAA group and 53.8 per cent in the ruptured AAA group (P < 0.00001). Mean cumulative survival was 8.6 years in the nonruptured AAA group and 1.1 years in the ruptured AAA group (P = 0.0001). These data support the conclusion that CEA and nonemergent AAA repair in octo- and nonagenarians are safe and effective in prolonging stroke-free and rupture-free survival. The utility of ruptured AAA repair in this age-group is less clear.     

Asymptomatic myocardial ischemia before and after surgical revascularization in patients with multivessel occlusive coronary disease

INTRODUCTION: The objective of this study was to examine the occurrence of asymptomatic myocardial ischemia prior to and after myocardial revascularization in patients with multivessel occlusive coronary disease. Asymptomatic ischemia can be described as real ischemia without anginal pain or other ischemic symptoms in patients with coronary disease or coronary artery spasm. Our study examined silent ischemia after myocardial revascularization. Early detection of silent ischemia is important for prevention of cardiac incidents. MATERIAL AND METHODS: We have examined patients with multivessel coronary disease with occurrence of continued preoperative silent ischemia. All patients have undergone ECG examination, exercise stress test and Holter-monitoring prior to and after myocardial revascularization. RESULTS: The investigation comprised 27 patients and their average age was 54.5 years. All patients with silent ischemia had a multivessel occlusive coronary disease and have undergone myocardial revascularization managed with triple or quadruple aortocoronary bypass surgery. Exercise stress test was performed postoperatively in elder patients, as well as ECG and Holter-monitoring. Silent ischemia was established in 21.6% of patients, while in 87.5% untreated diabetes mellitus was diagnosed. Silent ischemia most often occurred in the early morning hours and it was frequently associated with heart rhythm disturbances (VES) whereas these rhythm disturbances depended on the length of the ischemic episode. Intermittent 2nd degree atrioventricular block was found in one patient. CONCLUSION: Silent myocardial ischemia occurred in 21% of patients after myocardial revascularization. It is most often detected in the early morning hours and is associated with ventricular rhythm disorders. Silent ischemia is easily detected by simple examination procedures providing adequate therapy and prevention of cardiac incidents.     

Benefit of carotid endarterectomy in patients with symptomatic moderate or severe stenosis. North American Symptomatic Carotid Endarterectomy Trial Collaborators

BACKGROUND: Previous studies have shown that carotid endarterectomy in patients with symptomatic severe carotid stenosis (defined as stenosis of 70 to 99 percent of the luminal diameter) is beneficial up to two years after the procedure. In this clinical trial, we assessed the benefit of carotid endarterectomy in patients with symptomatic moderate stenosis, defined as stenosis of less than 70 percent. We also studied the durability of the benefit of endarterectomy in patients with severe stenosis over eight years of follow-up. METHODS: Patients who had moderate carotid stenosis and transient ischemic attacks or nondisabling strokes on the same side as the stenosis (ipsilateral) within 180 days before study entry were stratified according to the degree of stenosis (50 to 69 percent or <50 percent) and randomly assigned either to undergo carotid endarterectomy (1108 patients) or to receive medical care alone (1118 patients). The average follow-up was five years, and complete data on outcome events were available for 99.7 percent of the patients. The primary outcome event was any fatal or nonfatal stroke ipsilateral to the stenosis for which the patient underwent randomization. RESULTS: Among patients with stenosis of 50 to 69 percent, the five-year rate of any ipsilateral stroke (failure rate) was 15.7 percent among patients treated surgically and 22.2 percent among those treated medically (P=0.045); to prevent one ipsilateral stroke during the five-year period, 15 patients would have to be treated with carotid endarterectomy. Among patients with less than 50 percent stenosis, the failure rate was not significantly lower in the group treated with endarterectomy (14.9 percent) than in the medically treated group (18.7 percent, P=0.16). Among the patients with severe stenosis who underwent endarterectomy, the 30-day rate of death or disabling ipsilateral stroke persisting at 90 days was 2.1 percent; this rate increased to only 6.7 percent at 8 years. Benefit was greatest among men, patients with recent stroke as the qualifying event, and patients with hemispheric symptoms. CONCLUSIONS: Endarterectomy in patients with symptomatic moderate carotid stenosis of 50 to 69 percent yielded only a moderate reduction in the risk of stroke. Decisions about treatment for patients in this category must take into account recognized risk factors, and exceptional surgical skill is obligatory if carotid endarterectomy is to be performed. Patients with stenosis of less than 50 percent did not benefit from surgery. Patients with severe stenosis (> or =70 percent) had a durable benefit from endarterectomy at eight years of follow-up.     

Evaluation of carotid endarterectomy with sequential MR perfusion imaging: a preliminary report

BACKGROUND AND PURPOSE: Current indications for carotid endarterectomy are determined by balancing the relative risks of surgery with the benefits of reduced risk of subsequent stroke. Our purpose was to use MR perfusion imaging to assess patients being considered for carotid endarterectomy and to monitor sequential changes in MR perfusion characteristics after surgery. In particular, we wished to determine whether this technique could be used to detect changes that might be related to post-carotid endarterectomy hyperemia. METHODS: We used a single-section gradient-recalled echo sequence to investigate 14 patients being examined before possible surgery for carotid artery disease. In the 12 patients in whom carotid endarterectomy was performed, sequential studies were performed 3 to 5 days after surgery and at 3 months. Analysis of bolus-arrival-time (BAT) images was performed. RESULTS: Significant delays in preoperative BAT images of 0.89 seconds (range, 0.05 to 3.22 seconds) were apparent between hemispheres. Excluding the two patients with contralateral internal carotid artery (ICA) occlusion, early arrival, possibly indicating postoperative hyperemia, was seen in five patients immediately after carotid endarterectomy but resolved within 3 to 5 months after surgery. CONCLUSION: MR perfusion imaging shows differences in BAT between hemispheres in patients with ICA stenosis. Changes in perfusion characteristics after carotid endarterectomy are complex, and early BAT on the operative side can occur soon after endarterectomy in over half those patients without an occluded contralateral vessel. The significance of these findings with regard to patient outcome and risk of postoperative hyperemia requires further investigation.     

Coronary bypass surgery: what is changing? Analysis of 3834 patients undergoing primary isolated myocardial revascularization

We have previously demonstrated in primary cancer of the uterine cervix that tumor hypoxia, as determined polarographically, is strongly associated with clinical malignant progression of the disease. Having applied a similar methodological approach to investigate loco-regional relapses, we found a pronounced shift to more hypoxic oxygenation profiles in the recurrent tumors than in the primary tumors. Median pO2 values in 53 pelvic recurrences were significantly lower than the median pO2 values of 117 primary tumors of comparable sizes (7.1 +/- 1.1 mmHg vs. 12.1 +/- 1.0 mmHg, p = 0.0013). The differences in tumor oxygenation between primary and recurrent tumors mirrored the differences in the patients' 5-year survival probabilities. In the cohort of patients with pelvic relapses, median tumor pO2 < 4 mmHg indicated a significantly shorter median survival time as compared to median tumor pO2 > or = 4 mmHg. Our results further support our thesis that in cervical cancer, tumor hypoxia and clinical aggressiveness in terms of resistance to therapy and tumor dissemination, are interrelated.     

Carotid endarterectomy without a shunt for symptomatic lesions associated with contralateral severe stenosis or occlusion

PURPOSE: The purpose of this study was to assess the adequacy of thiopental protection against ischemic cerebral damage in patients undergoing carotid endarterectomy for symptomatic stenosis greater than 70% in association with contralateral stenosis greater than 70% or contralateral occlusion. METHODS: All patients (n=259) with severe bilateral carotid disease who underwent carotid endarterectomy for symptomatic stenosis greater than 70% were extracted from the database of an ongoing prospective carotid surgery study. Large-dose thiopental sodium without shunting was used for cerebral protection during endarterectomy. Asymmetric electroencephalogram changes during the operation, carotid occlusion time, stroke onset, and neuropathologic outcomes were analyzed. RESULTS: Three contralateral strokes occurred in the series, producing a cerebral morbidity/mortality rate of 1.2% (major 0.4%, minor 0.8%). Transient morbidity was 1.9% made of two reversible ischemic neurologic deficits and three transient ischemic attacks. New asymmetric electroencephalography changes were seen in 49 (19% patients, one of whom had transient deficit. Average occlusion time was 35 minutes. All strokes occurred within 24 hours of the procedure. Patients with previous stroke and and systemic hypertension seemed at greatest risk, and the contralateral hemisphere was the area at greatest risk. All transient deficits were ipsilateral and related to technical complications rather failed protection. CONCLUSIONS: Thiopental cerebral protection eliminates strokes caused by complications of shunting, prevents ischemic stroke during carotid occlusion for periods up to 67 minutes (average 35 minutes), allows meticulous management of the operative site, may modify or minimize clinical neurologic deficit, and in our experience has rendered intraluminal shunting obsolete.     

Effect of the Asymptomatic Carotid Atherosclerosis Study on carotid endarterectomy in Florida

BACKGROUND AND PURPOSE: The value of carotid endarterectomy (CEA) has been defined by several recent multicenter trials. The clinical effect of these trials remains undetermined since the Asymptomatic Carotid Atherosclerosis Study (ACAS) Clinical Advisory (dated September 28, 1994). METHODS: Patients undergoing CEA (ICD-9-CM 38.12) in nonfederal Florida hospitals were identified from the discharge database. Data were analyzed by federal fiscal year (FY, October 1 through September 30), comparing the years following the Advisory (FY95-FY96) to the preceding 3 years (FY92-FY94). RESULTS: There was a 68.3% increase in the number of CEAs during FY95-FY96 (mean FY92-FY94, 7,343; mean FY95-FY96, 12,356). This exceeded increases in total hospital discharges (4.5%), surgical discharges (2.2%), and the state's population (4.7%). The increase in CEAs spanned all patient demographic groups (gender, race, and age), although the magnitude was not consistent (range, 57.8% increase for 55 to 64 age group; 92.9% increase for > 84 age group). Concomitantly, there was a significant decrease in mortality (1.2% versus 0.8%), cardiac complication rate (ICD-9-CM 997.1, 4.1% versus 3.0%) and percentage of patients discharged > 7 days postoperatively (8.9% versus 4.9%). Mean length of stay declined 28% (5.8 versus 4.1 days), and mean adjusted charges declined 7% ($19,456 versus $18,055). Although the average case was less costly, the increased volume resulted in an estimated $56 million increase in annual hospital payments. CONCLUSIONS: The dramatic increase in the number of CEAs performed in the state of Florida after release of the ACAS Clinical Advisory suggests a causal relationship and mandates further cost-effectiveness analyses.