Ann Thorac Surg 2001;72:1542-1545
© 2001 The Society of Thoracic Surgeons
Original article: cardiovascular
Combined off-pump myocardial revascularization and carotid endarterectomy: early experience
Arshad M. Youssuf, MDa,
Ravindra Karanam, MDa,
Thomas Prendergast, MDa,
Bruce Brener, MDb,
Steven Hertz, MDb,
Craig R. Saunders, MDa,
Daniel J. Goldstein, MD*a
a Department of Cardiothoracic Surgery, Newark Beth Israel Medical Center, Saint Barnabas Health Care System, Newark, New Jersey, USA
b Department of Vascular Surgery, Newark Beth Israel Medical Center, Saint Barnabas Health Care System, Newark, New Jersey, USA
Accepted for publication July 10, 2001.
* Address reprint requests to Dr Goldstein, Department of Cardiothoracic Surgery, 201 Lyons Ave at Osborne Terrace, G5, Newark, NJ 07112, USA
e-mail: dgoldstein{at}sbhcs.com
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Abstract
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Background. Controversy remains regarding the optimal surgical management of patients with coexisting significant carotid and coronary artery disease. The debate has deepened by the evolution of new approaches for the treatment of both coronary and carotid disease. We report our early experience with combined off-pump coronary artery bypass (OPCAB) and carotid endarterectomy (CEA) for the treatment of patients with coexisting coronary and carotid disease.
Methods. Our computer database was examined to obtain patients and their demographics and clinical profiles. Operative reports were reviewed. Telephone interviews were conducted to assess follow-up status.
Results. Thirteen patients underwent combined OPCAB and CEA. Average age was 71 years. The CEA was performed with intraluminal shunting and patch reconstruction. On average, 3.6 bypass grafts were performed. There were no gross neurologic complications or myocardial infarctions. Excluding an outlier, mean length of hospital stay was 8.2 days. All patients were well on follow-up (2 weeks to 16 months).
Conclusions. A combined OPCAB and CEA strategy appears safe and effective. Further follow-up and experience is warranted before conclusions regarding potential benefits of this approach for staged or conventional OPCAB/CEA procedures can be made.
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Introduction
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Controversy remains regarding the optimal surgical management of patients with coexisting clinically significant carotid and coronary artery disease. The treatment options include combined coronary artery bypass grafting (CABG) and carotid endarterectomy (CEA), or a staged approach (CABG/CEA or CEA/CABG). Advocates of the combined approach cite low incidence of stroke and myocardial infarction as well as cost benefits to support their position [1–6]. Also cited is the only prospective randomized trial comparing combined and staged approaches, which demonstrated a statistically significant reduction in the incidence of stroke for patients undergoing the combined strategy [7]. However, the staged approach is supported by a recent meta-analysis of 16 retrospective comparative studies accounting for 1,764 patients that demonstrated an increased risk of stroke and a nonsignificant trend toward increased risk of death in combined operations [8].
Although a large multicenter, randomized study would potentially address this controversy, evolving technologies, including off-pump coronary bypass grafting (OPCAB) and carotid artery stenting, may impact outcomes and further cloud the controversy. Off-pump coronary bypass grafting, in particular, has emerged as a viable option in the treatment of multivessel coronary artery disease. Early results suggest that this approach is at least comparable to conventional bypass grafting with cardiopulmonary bypass and cardioplegic arrest [9–11].
The recognition that complete revascularization can be performed on the beating heart with reduced (ie, no cannulation) or no aortic manipulation has led to the application of these approaches on patients considered to be at high risk for perioperative stroke. Included in this category are patients with known or suspected aortic arch arteriosclerosis, advanced age, renal dysfunction, and carotid disease among others. At least one randomized trial comparing conventional revascularization with OPCAB is underway with neurologic outcome as its primary endpoint.
In an effort to reduce the incidence of perioperative stroke in the high-risk population of patients with simultaneous critical coronary and carotid disease, we have approached these patients with combined OPCAB and CEA. The present study represents our early experience with this innovative approach.
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Patients and methods
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Patients
Between August 1, 2000, and April 30, 2001, 15 consecutive patients underwent combined coronary and carotid revascularization. Of these, 13 underwent combined OPCAB and CEA. For the remaining 2 patients, combined conventional CABG and CEA were performed. In the first instance, the heart was dilated and hypertrophic precluding safe performance of OPCAB. In the second case, hemodynamic instability developed in the patient at the conclusion of the CEA, and immediate sternotomy and CABG with cardiopulmonary bypass support were undertaken. These 2 patients were excluded from the study. Because of limitations of the database, we could not assess the number of patients who underwent staged operations during the study period.
Data acquisition
The data were collected retrospectively for the first 4 patients in the series and prospectively from the remaining 9 patients. A daily updated computer database (CAOS, Intelligent Business Solutions, Clemmons, NC) was used to obtain demographic profiles, operative reports, and complications. Details from the operative procedures were obtained by direct communication with vascular and cardiac surgeons as needed. Follow-up information was obtained from chart review and direct contact with the patient or referring cardiologist.
Preoperative assessment and patient selection
At our institution, patients referred for coronary revascularization undergo selective screening for carotid disease. Those with any of the following criteria are submitted for color-flow duplex scanning: a history of transient ischemic attack or stroke, an audible carotid bruit, older than 60 years, presence of left main disease or peripheral vascular disease. Patients are considered candidates for CEA when more than 70% internal carotid artery stenosis is documented or unstable plaque morphology (regardless of degree of stenosis) is found. The final decision to perform OPCAB is made at the time of operation and is based on history and clinical findings. Considerations include the presence of an intramyocardial left anterior descending artery, size and quality of coronary targets, presence of cardiomegaly, and angiographic or echocardiographic evidence of worrisome aortic arteriosclerosis. Noncardiac factors taken into consideration include advanced patient age, presence of renal dysfunction and peripheral vascular disease, and surgeon comfort with off-pump revascularization. All patients with coexisting critical and coronary disease are approached as potential candidates for combined OPCAB/CEA procedure but the final decision regarding operative strategy is made by the cardiothoracic and vascular surgeon.
Intraoperative strategy
After establishment of general endotracheal anesthesia, the CEA was performed by a vascular surgeon in all instances. All CEAs were performed at normothermia with the use of intraluminal shunts. Following endarterectomy, carotid reconstruction was always performed with either a saphenous vein or Dacron (C.R. Bard, Haverhill, PA) patch. Saphenous vein conduits for myocardial revascularization were harvested simultaneously, but median sternotomy was not performed at this time. The CEA wound was packed open until reversal of systemic heparin with protamine.
Off-pump coronary artery bypasses were always performed through a median sternotomy. Transesophageal echocardiography was performed routinely. The ascending aorta, aortic arch, and descending aorta were examined for presence of significant atherosclerotic disease (ie, mobile atheromata, wall thickening, etc). The ascending aorta was additionally evaluated by the surgeon based on transesophageal echocardiography findings and manual examination. Heparinization protocol included measurement of base line activated clotting time (ACT), initial heparin dose of 250 to 300 U/kg before internal mammary artery division, repeat ACT measurements at 20-minute to 30-minute intervals, and reheparinization to maintain the ACT longer than 450 seconds. Of note, the initial heparin dose was given depending on the base line ACT obtained after completion of the CEA. Vascular surgeons usually administered 10,000 U of heparin before carotid clamping. Following conduit harvest (left internal mammary artery, radial artery, or saphenous vein), anastomoses were performed with the aid of the Octopus (Medtronic Inc, Minneapolis, MN) stabilizing system. When significant aortic disease was found, and at the discretion of the operating surgeon, the aorta was not used for the creation of proximal anastomoses. In cases in which the aorta was used, great efforts were made to use a single partial aortic occlusion period with a side-biting clamp in an area of ascending aorta deemed to be free of atherosclerotic disease. The CEA wound was closed after protamine reversal and a drain was left in the neck wound for postoperative fluid drainage.
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Results
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Thirteen patients have undergone combined OPCAB and CEA at our institution since OPCAB approaches were introduced. All patients were referred for coronary revascularization and were then worked up for coexistent carotid disease based on the presence of the study criteria. The average age was 71 ± 8.5 years (range 58 to 81 years). There were 9 men (69%). Comorbid conditions were common and are outlined in Table 1. Five patients had a history of stroke (n = 4) or transient ischemic attack (n = 1). The other 8 patients had 90% or greater stenosis of an internal carotid artery. All patients had at least three-vessel coronary artery disease and 8 patients (62%) had coexisting significant left main disease (more than 50% stenosis).
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Table 1. Clinical Profile of 12 Patients Undergoing Combined Off-Pump Coronary Artery Bypass Grafting and Carotid Endarterectomy
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Surgical priority was urgent for 9 patients and elective for the remaining 4. On average, 3.6 coronary artery bypass grafts were performed (range 2 to 5 grafts). In 4 patients, the aorta was not manipulated at all and proximal anastomoses were taken from the left internal mammary artery. No perioperative stroke, transient ischemic attack, or myocardial infarction occurred. Although no detailed neuropsychometric testing and no imaging studies of the head were performed postoperatively, no obvious neurocognitive dysfunction was seen. No myocardial infarctions occurred (as determined by electrocardiogram, enzymes), but new onset atrial fibrillation developed in 6 (46%) patients. No neck or sternal wound problems developed. One patient with severe chronic obstructive pulmonary disease developed respiratory failure postoperatively, requiring tracheostomy and long-term ventilatory support. Postoperative length of stay averaged 14.3 ± 22 days (range 4 to 88 days). If the 88-day outlier is excluded, the average length of stay was 8.2 ± 3 days.
Postoperative follow-up was 100% and ranged from 2 weeks to 14 months. One patient was readmitted for reasons unrelated to either operation. At last follow-up, all patients were alive and well with no ongoing cardiac or neurologic events.
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Comment
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Stroke after cardiopulmonary bypass can result from an embolic, ischemic, or hemorrhagic insult to the brain. Embolic debris can arise from the heart, carotid arteries, and aorta, whereas ischemia is likely the result of low-flow phenomena associated with nonpulsatile extracorporeal circulation. Hemorrhage, however, is a rare cause of perioperative stroke despite the extreme levels of anticoagulation routinely used in cardiopulmonary bypass operations [12].
In the present series, we extended the use of OPCAB to patients with simultaneous critical coronary and carotid arteriosclerosis. In 8 of 13 patients, asymptomatic critical carotid disease was found during preoperative evaluation. The other 5 patients had preoperative neurologic events that led to the investigation of the cerebrovascular system. Excluding the patient with prolonged postoperative ventilatory support, the mean length of stay was less than 9 days, with 1 patient discharged on the fourth postoperative day. There were no myocardial infarctions or gross neurologic complications, and all patients were asymptomatic on follow-up. A high incidence of atrial fibrillation (46%) was noted. The Society of Thoracic Surgeons database benchmark for this complication is 19.7%. Given the small number of patients in our series, assessing the statistical significance of this finding was difficult.
Adoption of a combined strategy of beating heart revascularization and CEA carries several benefits. First, the combined procedure may eliminate some of the potential untoward effects of nonpulsatile extracorporeal circulation (systemic inflammatory response, low-flow phenomena, etc). Second, by minimizing aortic manipulation, it reduces the chance of atheroembolism from an aortic source. Third, by combining OPCAB with CEA, the risk of embolism from the carotid source is potentially reduced. Lastly, the risks and costs of an additional operation are avoided. Investigators have suggested that screening for carotid disease and prophylactic CEA in patients with coronary artery disease submitted for operation results in significant reduction in the risk of perioperative stroke [13].
During the study period, all but 2 patients with critical carotid and coronary disease referred to our service underwent OPCAB and CEA as described. The remaining 2 patients underwent conventional CABG/CEA for reasons described earlier. Thus, despite the mostly retrospective nature of the study, no selection bias could be discerned. Certain limitations of the study, however, must be mentioned. First, this study was observational and noncomparative, and had a small number of patients. Secondly, although gross neurologic complications were not seen, it is possible that subtle neurocognitive deficits were missed because precise testing and head imaging were not undertaken in any of these patients. Clearly, neuroprotective effects of our approach cannot be assumed given the small size of the series and the incomplete postoperative neurologic evaluation. Third, the follow-up of these patients was limited and complications related to the OPCAB procedure (eg, graft closure) cannot be estimated.
In our hands, a combined OPCAB and CEA strategy for patients with critical disease in both circulations is safe and effective and has become our standard of practice when anatomic factors permit it. Certain factors preclude performance of the combined procedure, including hemodynamic instability, noncritical carotid stenosis (ie, less than 80%), patient’s choice, and anatomic factors rendering OPCAB difficult or unsafe to perform. In general, presence of intramyocardial vessels, significant cardiomegaly, moderate (2+) mitral regurgitation, and small targets render off-pump revascularization much more challenging. As with all methods, the surgeon’s comfort with the procedure remains the critical factor in the decision to proceed or abandon the beating heart approach.
Further follow-up of these patients and increased experience is welcomed and necessary before conclusions regarding potential benefits of this approach in comparison with staged or conventional CABG/CEA procedures can be made. Our study does not represent an endorsement of any one approach, as it is only an observational study of one possible strategy for the management of these complex patients. Whereas randomized evaluation is always desirable, the multiple variables (staged versus combined, order of staging, and OPCAB versus conventional CABG) would require too many different study arms to make it a practical and reasonable trial.
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Acknowledgments
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We thank Gladys Madrid, RN, and Theresa Evangelista for their invaluable assistance with data retrieval and analysis.
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References
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Abstract
Introduction
