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Ann Thorac Surg 1999;68:431-436
© 1999 The Society of Thoracic Surgeons
a Divisions of Division of Cardiac Surgery, Sinai Hospital of Baltimore, Baltimore, Maryland, USA
b Division of Cardiac Surgery,Washington Adventist Hospital, Takoma Park, Maryland, USA
Address reprint requests to Dr Fonger, Adventist Heart, Washington Adventist Hospital, 7610 Carroll Ave, Suite 440, Takoma Park, MD 20912
e-mail: jfonger{at}heartnet.org
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Abstract |
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Methods. Patients who had symptomatic coronary artery disease limited to a single coronary distribution were selected. Coronary targets were grafted with the pedicled gastroepiploic artery through a small midline epigastric incision. Patients were followed with scheduled outpatient clinic visits, Doppler examination, and selective recatheterization.
Results. Between May 1995 and November 1997, 74 patients underwent gastroepiploic artery minimally invasive direct coronary artery bypass grafting; 33 (45%) had a primary operation and 41 (55%), a reoperation. Grafting was performed to the distal right coronary artery (n = 38), the posterior descending artery (n = 28), or the distal left anterior descendng coronary artery (n = 8). There were six deaths (8%) within 30 days after operation. Twenty patients (28%) underwent recatheterization; there were two graft occlusions, two graft stenoses, and five anastomotic stenoses. Of 60 patients seen 2 or more weeks after operation, 53 (88%) had resolution of anginal symptoms at a mean follow-up of 10.9 months (range, 0 to 30 months).
Conclusions. Inferior minimally invasive direct coronary artery bypass grafting with the gastroepiploic artery avoids the risks of repeat sternotomy, aortic manipulation, and cardiopulmonary bypass. Patency rates, however, were lower than expected, and there is significant morbidity and mortality associated with high-risk patients undergoing the procedure. Continued follow-up is essential to evaluate long-term graft patency and patient survival.
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Introduction |
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There are several advantageous features of MIDCAB grafting, including small, directed incisions, obviation of cardiopulmonary bypass, and avoidance of great-vessel or existing graft manipulation. Repeat sternotomy has known risks: injury to patent grafts, the heart, and the great vessels; embolization of atherosclerotic debris from the aorta or diseased grafts; and wound infection. In patients having reoperation, conventional coronary artery bypass (CAB) is associated with both prolonged cardiopulmonary bypass and increased operative times because of more extensive dissection.
Use of the gastroepiploic artery (GEA) for revascularization of the inferior surface of the heart has been successful when performed during conventional CAB [5–9]. This pedicled arterial conduit is long and well suited to a minimally invasive approach. Our initial experience, reported here, demonstrates that this technique can reduce some of the morbid events associated with reoperations, such as supraventricular arrhythmias and blood transfusion. Although inferior MIDCAB grafting with the GEA does not eliminate the risks of reoperative procedures or associated comorbid events, patients can be expected to recover more rapidly and leave the hospital sooner than with conventional repeat CAB procedures.
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Patients and methods |
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TopAbstractIntroductionPatients and methodsResultsCommentReferences |
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The right GEA was dissected proximally to obtain optimal caliber and was gently palpated for evidence of plaque. Side branches were carefully ligated, and adequate length was ensured prior to grafting. Intraluminal injection of diluted papaverine hydrochloride (60 mg in 100 mL of saline solution) combined with verapamil hydrochloride (10 mg in 50 mL of saline solution) was routinely used for this conduit, as the vessel is prone to spasm from operative manipulation. The GEA pedicle was brought anterior to the stomach and left lobe of the liver. For distal right coronary artery (RCA) and left anterior descending coronary artery targets, the pedicle was directed over the diaphragm; for deeper posterior descending artery targets, the pedicle was routed through a small incision in the right hemidiaphragm to ensure adequate graft alignment with the anastomosis.
After 10,000 units of intravenous heparin sodium was administered, a retraction tape of silicone elastomer (Quest Medical, Dallas, TX) was plated around the native coronary artery proximal to the intended site of grafting. To prevent fracturing of distal luminal plaque, heavily diseased targets are no longer occluded distally. A 5-minute test occlusion was undertaken routinely to confirm hemodynamic stability prior to proceeding with the arteriotomy and grafting.
An arteriotomy was fashioned in the target vessel, and the site of grafting was stabilized using only a hand-held right-angled clamp with rubber bolsters. The conduit was anastomosed end-to-side in an antegrade fashion using a 7-0 Prolene single parachute technique. Intraoperative graft flow was measured using a transit-time ultrasound flow probe (Transonic Systems, Inc, Ithaca, NY) to assist in detection of technical problems with the anastomosis or native coronary artery prior to closure. After completion of the anastomosis, the GEA pedicle was secured to the epicardium to ensure proper orientation. A soft Hemovac drain was then directed across the peritoneum into the pericardium and into the pleural cavity if it had been opened during the dissection for exposure. The diaphragm was repositioned but not reattached, and the fascia and soft tissue were closed in layers.
Patient follow-up
Serial cardiac-enzyme analysis was systematically performed on all patients at 1 hour, 8 hours, and 16 hours postoperatively, and additional enzymatic analysis was carried out as indicated. Patients were followed prospectively after operation with clinic visits at 2 weeks, 3 months, and then annually. Transcutaneous Doppler velocity evaluation of the graft was done at 2 weeks, 3 months, and 1 year to confirm patency. Exercise stress or Persantine (dipyridamole) thallium testing was done at 3 months to evaluate improvement in myocardial perfusion in the grafted distribution. Coronary angiography was performed selectively for persistent or recurrent anginal symptoms, failure to visualize the graft on postoperative Doppler velocity evaluation, and major persistent, reversible ischemic defects on 3-month stress thallium testing.
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Results |
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TopAbstractIntroductionPatients and methodsResultsCommentReferences |
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Mortality
Six patients (8.1%) died within 30 days after operation; four deaths were due to cardiac-related causes. Four of the patients in the group having reoperation and 2 patients in the primary operation group. Three patients (4.1%) died late at periods ranging from 3 to 22 months after operation; one death was due to a presumed cardiac cause. By Kaplan-Meier analysis, freedom from death was 89% (95% confidence interval, 79% to 94%) at 12 months and 84% (95% confidence interval, 68% to 92%) at 24 months. Mortality data are summarized in Table 2.
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Five patients (6.8%) had development of atrial fibrillation or supraventricular tachycardia during the postoperative period; in 4, episodes occurred and were treated prior to discharge. The fifth episode occurred and was treated after discharge. Two patients (2.7%) sustained a stroke or other major neurologic impairment. In 1 of them, visual changes consistent with neurologic deficit developed 10 days after operation. Results of carotid ultrasound evaluation and transesophageal echocardiography were normal, and the symptoms failed to resolve with anticoagulant therapy. In the other patient, symptoms consistent with a small right-sided stroke developed within 4 weeks after operation; the symptoms resolved spontaneously.
Infections of the primary operative site developed in 6 patients (8.1%). One of them required operative debridement and revision of the incision. The remaining 5 patients had minor infections treated in the clinic with simple incision and drainage, packing, and antibiotics.
Two patients (2.7%) required reexploration, 1 for bleeding and 1 for hemodynamic instability. In the first patient, a 74-year-old woman weighing 42 kg, a bleeding site was identified on the transverse mesocolon and ligated. The patient continued to have diffuse oozing and required multiple transfusions; multisystem organ failure developed, and resulted in death from renal failure on postoperative day 4. The second patient had sudden hemodynamic collapse 2 hours after operation and was returned to the operating room for emergent conventional CAB. No discrete bleeding site or collection of blood was identified.
Conversion to conventional bypass grafting
Two patients (2.7%) required conversion to conventional CAB techniques. Conversion was accomplished prior to grafting in 1 patient when the 5-minute test occlusion period resulted in hemodynamic instability. Conversion was performed emergently 2 hours after operation in the other patient because of hemodynamic instability, as already described.
Length of stay
Mean overall postoperative length of stay for all patients was 2.6 days (range, 0 to 23 days). Mean overall length of stay excluding hospital deaths was 2.3 days (range, 1 to 8 days).
Recatheterization and reintervention
Twenty patients (27%) underwent recatheterization for symptoms, inadequate graft flow on Doppler evaluation, persistent defect on stress thallium testing, or during a planned procedure on another vessel (Table 3). Five patients had normal grafts, and 6 had raised flap or progression of native coronary vessel disease distal to the graft or in a different coronary distribution.
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Five patients (6.8%), 3 in the primary operation group and 2 in the reoperation group, had development of stenosis at the anastomosis. One stenosis occurred within the perioperative period, two occurred within 3 months of operation, and two occurred more than 3 months after operation. All but 1 patient had successful percutaneous dilation of the anastomotic stenosis.
Follow-up
Intraoperative graft flow assessed by transit-time ultrasound averaged 17.1 mL/min (range, 1 to 63 mL/min). Routine transcutaneous Doppler velocity analysis of the graft was performed on 50 patients at 2 weeks, 42 patients at 3 months, and 20 patients at 1 year; no asymptomatic patient showed evidence of graft occlusion or stenosis.
Stress thallium testing was performed on 45 patients (60.8%) at 3 months. Ten patients had a mild persistent ischemic defect; all of these grafts were evaluated by Doppler velocity studies and demonstrated flow. Three of these patients had ischemic defects that precipitated recatheterization; 2 of them had anastomotic stenoses, and 1 had a distal native coronary artery stenosis. All had successful percutaneous dilation of these lesions.
Sixty (92.3%) of 65 surviving patients were evaluated for symptoms during clinic visits at 2 weeks, 3 months, and then annually. One (1.7%) had persistent symptoms, and 6 (10%) had recurrent symptoms. Fifty-three (88.3%) of the 60 patients seen in the clinic had resolution of symptoms, with or without additional medical therapy.
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Comment |
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TopAbstractIntroductionPatients and methodsResultsCommentReferences |
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The GEA is a relatively versatile vessel that can be used to bypass a variety of coronary vessels. Although patency rates are generally lower than those associated with left internal mammary artery grafts, GEA graft patency has been shown to exceed that of right internal mammary artery grafts [10]. In addition, this conduit is generally larger and longer than the inferior epigastric artery [11, 12]. When an appropriate length is obtained, the caliber of the distal end of the GEA matches that of the native coronary arteries well. However, flow and size are not as robust or as consistent as those found in the left internal mammary artery [13]. Extensive proximal surgical dissection is important to assure an adequate caliber in the portion of the tapered conduit that is actually used. Intraluminal injection of papaverine and verapamil will help avoid perioperative spasm of the conduit.
Experience with the GEA in MIDCAB grafting has been limited to a few case reports and one small series of patients having reoperation [14, 15]. These reports have been encouraging, with a few patients studied at 1 year having patent grafts. The MIDCAB techniques for using the GEA have been adapted from the conventional approaches and include harvesting the conduit on a pedicle and routing this pedicle either through or over the diaphragm, depending on the location of the target vessel [16]. Suma and associates [17] reported favorable results with GEA grafting of the left anterior descending coronary artery. We used this approach through a minimally invasive incision for 8 patients in this series with recurrent distal disease in the left anterior descending coronary artery after internal mammary artery grafting.
Minimally invasive direct coronary artery bypass grafting using the GEA in this series of patients was associated with a lower rate of supraventricular tachycardia (6.8%) than traditionally noted with conventional CAB operations. The incidence of local wound infection (8.1%) was higher than anticipated; however, only 1 patient required operative debridement of the wound, and there were no episodes of sternal infection or intraabdominal abscess formation. The postoperative length of stay was markedly lower in this series compared with that for conventional CAB and is not dissimilar from the stays in other MIDCAB series.
Graft occlusion and stenosis rates were higher than average in this series, and the events occurred early after MIDCAB grafting. Anastomotic stenoses occurred at varying intervals during follow-up, suggesting a relationship to perianastomotic healing during the first 6 months after operation. Of the 9 patients with graft or anastomotic occlusion or stenosis, 6 had involvement of grafts to the RCA. This may reflect unrecognized disease in the RCA, and therefore grafting to the posterior descending artery is recommended instead. Importantly, none of the patients with GEA grafting to the distal left anterior descending coronary artery had problems with graft or anastomotic stenosis.
Transcutaneous Doppler velocity evaluation of gastroepiploic conduits in this experience was not predictive of graft stenosis, although occlusion is easily identified. Other authors [18, 19] have found noninvasive patency evaluation of these grafts to be quite reliable. Surprisingly, percutaneous transluminal angioplasty of these graft and anastomotic stenoses has been successful in the majority of patients, but it requires some experience in negotiating the celiac axis and gastroduodenal artery to reliably perform the procedure. Occluded grafts are understandably more difficult to open, as seen in the cases of the 2 patients in this series and 5 patients in another report [20].
Use of MIDCAB grafting in this series of patients did not lower the incidence of early mortality compared with conventional CAB and was associated with an increased incidence of perioperative myocardial infarction on routine enzymatic surveillance. Stringent methods were used to search for evidence of myocardial infarction to carefully evaluate this new approach. These findings can partially be attributed to a higher preoperative risk in this subset of patients. Many patients referred for MIDCAB grafting are having reoperation (55% in this series) and have advanced native coronary artery disease as well as numerous comorbid conditions, thus, they are in a high-risk category for conventional CAB procedures.
Use of the GEA itself has not been associated with an increased risk in the conventional CAB patient population [21]. However, the higher rates of mortality and perioperative infarction underscore a number of important issues when the MIDCAB approach is applied. This initial experience represents the early learning curve with respect to patient selection, conduit preparation and routing, MIDCAB anastomosis without the help of automated stabilization, and handling of the distal native coronary artery in the beating heart. The technical difficulty of this approach and the anterior routing of the GEA conduit may both have contributed to the higher than expected rates of graft stenosis, myocardial infarction, and early mortality.
In conclusion, MIDCAB grafting using the GEA is a technically feasible yet challenging operation that results in satisfactory early patency rates and relief of patient symptoms. The GEA is a versatile vessel that can be used as a pedicled conduit to graft a variety of coronary targets on the inferior and anterior surfaces of the heart. Compared with conventional CAB grafting, this approach reduces the incidence of postoperative supraventricular arrhythmia, markedly shortens postoperative length of stay, and allows patients to return to normal activity more rapidly. Importantly, this operative approach in our series did not reduce early mortality and had a 20% rate of enzymatic perioperative myocardial infarction. With careful patient selection, however, MIDCAB grafting using the GEA conduit will continue to develop as an important adjunctive approach for the high-risk patient with limited but refractory inferior coronary artery disease.
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TopAbstractIntroductionPatients and methodsResultsCommentReferences |
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This article has been cited by other articles:
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  D. Glineur, P. Noirhomme, A. Poncelet, C. Hanet, P. Astarci, R. Verhelst, P. Y. Etienne, and G. El Khoury Gastroepiploic Artery Minimally Invasive Grafting in Reoperative Patients With Patent Mammaries Ann. Thorac. Surg., May 1, 2005; 79(5): 1606 - 1609. [Abstract] [Full Text] [PDF]
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