Staged operations for severe carotid and coronary occlusive disease

Antunes Pedro; Ferrão de Oliveira José; Eugénio Luís; Antunes Manuel

Cardiothoracic Surgery. University Hospital
Coimbra. Portugal

The treatment options for asymptomatic patients who present severe carotid stenosis which is incidentally found during preparation for CABG is still matter of debate. The choices vary from a simultaneous (same anesthetic) to a staged procedure, with carotid endarterectomy performed several days prior to (staged approach), or after (reversed staged approach) coronary revascularization. The purpose of this paper is the evaluation of our early results in patients who underwent staged carotid and coronary procedures. To the best of our knowledge, this is the first study on the results of the staged approach as the routine method to treat all patients with concomitant carotid and coronary arterial disease.

During a 7-year period ending December 1998, 60 (1.9%) of 3,242 consecutive patients subjected to isolated coronary artery bypass grafting (CABG) underwent carotid and, subsequently, coronary surgery (staged operation) for severe concomitant arterial disease. Patients who had undergone carotid surgery in the past, without indication for coronary surgery at the time, were, by definition, not included in this series. Diagnosis and general treatment protocol. All patients were admitted to the hospital because of coronary disease. They underwent carotid artery evaluation before CABG on a selective basis, depending mainly on the auscultation of a bruit in the neck. Although most patients (66.6%) were submitted to a duplex study, the diagnosis and severity of the disease was made by carotid angiography in all cases. Hemodynamically significant stenosis was defined as a reduction of the luminal diameter of the carotid artery greater than 70%. All patients were treated with a staged approach, i.e., carotid endarterectomy (CEA) first, followed by CABG as a second operation. In patients who were presented with bilateral carotid disease, surgery in the two arteries was performed in different anesthetic times. As a rule, CABG was performed more than 2 weeks from CEA, in a different period of hospitalisation, unless the cardiac condition dictated earlier surgery.
Preoperative data. The mean age of the 60 patients was 65.0 ± 5.3 years (range 49 - 78 years) and 46 (76.7%) were male. Fifteen (25.0%) patients were diabetic and 37 (61.6%) had dislipidemia. Twenty-eight (46.7%) and 32 (53.3%) patients were in class I/II and III/IV of the CCS, respectively. Three (5.0%) patients, otherwise stable the day of CEA, had been on intravenous antianginal medication for the last 2 days. A history of previous myocardial infarction was recorded in 36 patients (60.0%). Forty nine patients (81.6%) had triple, 10 (16.7%) double and 1 (1.7%) single vessel coronary disease and 14 patients (26.6%) had left main disease. Left ventricular function was normal in 25 patients (41.7 %), and moderately decreased in 35 (58.3%). A comparison of the clinical, angiographic and operative data of these patients with those who had no carotid disease is shown in table 1. Eleven patients (18.4%) were symptomatic. Preoperative neurologic symptoms and anatomy of the carotid disease of the group of patients who were submitted to the staged procedure are presented in table 2. Unilateral disease was present in 54 patients (90.0 %) and bilateral in 6 (10.0 %).
Operative technique- Carotid and coronary surgery. In all but two cases (3.1%) the CEA was performed under general anesthesia. The CEA was performed with direct clamping of the artery (mean 19.6 ± 6.1 min) in all patients but one who had a temporary shunt inserted. Coronary surgery was performed under mild systemic hypothermic cardiopulmonary bypass (30-32ºC) and ventricular fibrillation without aortic occlusion. Internal mammary artery (IMA) grafts were used in 59 patients (98.3 %), including 4 (6.6 %) in whom both IMAs were used. An average of 2.9 coronary branches were bypassed per patient. CEAs were performed in 15 patients (25.0%). The cardiopulmonary bypass time was 64.6 ± 17.5 minutes.

Table 1

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Table 2

Results:

Clinical correlations. The clinical, angiographic and operative cardiac data are listed in table 1 and compared with those of 3,182 patients who had isolated CABG during the same period. The staged operation group was significantly older, had more women and more patients in class III of CCS, with hypertension and with left main disease. There was also a significantly higher incidence of coronary endarterectomy and a lower incidence of use of bilateral IMA.
Carotid Surgery and staging interval. There were 66 isolated CEAs performed in the 60 patients with no mortality. One patient (1.5%) had an ipsilateral permanent stroke on the first postoperative day. Computer tomography (CT) showed a major area of infarct and non-invasive carotid artery evaluation revealed patency at the CEA site. Two patients (3.0%) had ipsilateral transient ischemic episodes, with negative CT scans and also showed permeable carotids. There were 2 cases (3.0%) of myocardial infarction, evolving without hemodynamic instability. Another 2 patients (3.0%) developed unstable angina that did not respond to medication and required urgent CABG. With the exception of the two who required urgent coronary surgery, all patients returned home in a stable condition. Hospital stay was 6.0 ± 3.4 days. Through to coronary surgery there was no mortality or new neurologic complications or myocardial infarctions. Nevertheless, two patients (3.0%) developed unstable angina and required hospitalisation with successful medical control. The mean staging interval was 39.5 days.
Coronary surgery - perioperative results. Perioperative events are listed in table 3. There was one death (1.7 %) due to stroke. In the immediate postoperative period, 5 patients (8.3%) required inotropic support. One patient (1.7%) was re-operated due to bleeding and another to sternal dehiscence. One patient (1.7%) had perioperative myocardial infarction. There were 3 cases (5.0%) of perioperative stroke (one reversible and two permanent), all ipsilateral to the CEA. One, which was the cause of the single in-hospital death, occurred in a patient with a history of permanent stroke who had bilateral CEA. This patient did not wake up from anesthesia and died on the 10th day. Necropsy showed a major infarcted area of the right hemisphere and extensive right carotid thrombosis. The second patient, who also had a history of permanent stroke, was submitted to urgent CABG 6 days after left CEA, due to unstable angina. In the immediate postoperative period, he developed a severe and prolonged hypotension, as a result of major bleeding from the aortic cannulation site, and a right hemiplegia was noted when he woke up. The third patient sustained an ipsilateral ischemic stroke on postoperative day 2, probably embolic from the CEA site (left CEA performed 27 days earlier), which was patent as assessed by non-invasive study. This patient was ambulatory, albeit with right arm weakness, at discharge. There were no cases of transient ischemia. The hospital stay was 8.6 + 3.3 days.

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Table 3

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Discussion:

The incidence of major perioperative neurologic complications in unselected patients undergoing coronary surgery has been reported between 1% and 6%. Several reports indicate that significant carotid artery stenosis is an important, and possibly the strongest, incremental risk factor for perioperative stroke in patients undergoing isolated myocardial revascularization. Reports of routine carotid evaluation before CABG have documented significant internal carotid stenosis (>70%) in 3% - 12% of patients. In this study, the diagnosis of severe carotid disease was secondary in 1.9% of the patients who have been elected for isolated CABG. This percentage could obviously underestimate the real incidence of the carotid disease because routine preoperative evaluation of all CABG patients, other than auscultation of bruits, has not been carried out.
Some randomised trials have now unequivocally proven a significant benefit of CEA over continued medical treatment for patients with symptomatic and, even more recently, with asymptomatic severe carotid artery stenosis. The NASCET study showed that CEA in symptomatic patients with 70-99% carotid stenosis decreased the 2-year rate of ipsilateral stroke from 26% in medically treated patients to 9% in surgically treated patients. The ACAS study demonstrated a reduction in total ipsilateral events in patients with >60% carotid stenosis from 18% to 7% over 5 years.
We believe that the rational approach for virtually all patients who present severe combined arterial disease is to submit them to carotid surgery before myocardial revascularization. The surgical options are then either a simultaneous procedure (same anesthetic) or a staged approach whereby the CEA is performed several days prior to CABG. No well-designed prospective randomised trial has clarified this problem. Consequently, the optimal strategy for management remains undefined and each centre must elect its own treatment plan. In 1992 we adopted the staging approach to treat all patients who present concomitant arterial carotid and coronary disease. To our knowledge, this is the first study to report the results of the staged operation as the only routine method to treat all patients. The results reported herein, with no mortality and an incidence of 3.3% of MI, lends support to the safety of this surgical approach. The global incidence of mortality (1.7%) and composite death and stroke (8.2%) rates in this report compare favourably with those in the literature for patients managed using a combined approach (table 5). By contrast, our incidence of MI was higher (4.7%) but still acceptable. On the other hand, we did not expect such a high incidence of stroke (6.5%). This result underscores the multifactorial aetiology of stroke after CABG, particularly in these high-risk patients, but, we believe, is insufficient to question the importance of prophylactic CEA in reducing the incidence of stroke. We believe that the cerebrovascular accident rate in our patients would have been even higher if they had not undergone the CEA before the CABG.

Table 4

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Table 5

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