Ann Thorac Surg 2004;78:1610-1613
© 2004 The Society of Thoracic Surgeons
Original article: cardiovascular
Surgical Reconstruction of the Left Main Coronary Artery: Fresh Autologous Pericardium or Saphenous Vein Patch
Ehud Raanani, MDa,*,
Alexander Kogan, MDa,
Yaron Shapira, MDb,
Alex Sagie, MDb,
Ran Kornowsky, MDb,
Bernardo A. Vidne, MDa
a Department of Cardiothoracic Surgery, Tel Aviv, Israel
b Department of Cardiology, Rabin Medical Center, Beilinson Campus, Petah Tiqwa, affiliated with Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
Accepted for publication May 4, 2004.
* Address reprint requests to Dr Raanani, MD, Department of Cardiac Surgery, Sheba Medical Center, Tel-Hashomer, Israel 52621
ehud.raanani{at}sheba.health.gov.il
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Abstract
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BACKGROUND: Isolated stenosis of the left main coronary artery is usually treated by coronary bypass surgery. However, this approach restores a less physiologic perfusion of the myocardium that leads to occlusion of the left main coronary artery, and restores only a retrograde perfusion of a rather extensive myocardial area. Coronary ostial plasty has been described as an alternative surgical technique in isolated ostial left main coronary artery stenosis without calcification. We review our experience with 15 patients.
METHODS: After placing the patient on cardiopulmonary bypass and aortic cross clamping, the main pulmonary trunk was retracted laterally. The left main coronary artery was approached anteriorly through a curved aortotomy. Reconstruction was performed using fresh pericardial patch or saphenous vein that was tailored as a patch.
RESULTS: There were no early mortality or perioperative myocardial infarctions. During mean follow-up of 55 ± 39 months, no patients had any cardiac events or required repeated coronary intervention. All patients underwent follow-up transesophageal echocardiography, which demonstrated a wide open left main coronary artery (range 3 to 8 mm), normal flow pattern by pulsed-wave Doppler, and no aneurysmal dilatation or calcification of the onlay patch. Coronary angiography and intravascular ultrasound were performed in 2 patients because of nonspecific chest discomfort. In both cases, the left main coronary artery was found to be wide open, and there were no signs of patch calcification.
CONCLUSIONS: Surgical reconstruction of the left main coronary artery is safe and effective for the treatment of selected cases of isolated left main stenosis. The use of autologous pericardium appears to be as safe as saphenous vein patch. Neither method was associated with postoperative aneurysmal dilatation or calcification.
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Introduction
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Researchers estimate that isolated left main coronary artery (LMCA) stenosis accounts for less than 1% of all cases of coronary artery disease [1, 2]. In young middle-aged women, LMCA stenosis is caused by idiopathic fibromuscular dysplasia [3]. Other causes include isolated atherosclerotic plaque or inflammatory diseases such as Takayasu aortitis [4], radiation therapy [5], and syphilitic aortitis [6].
Treatment with coronary ostial plasty was introduced in 1965 [7, 8] but was soon abandoned because of the high operative risk. Twenty years later, the formulation of stricter inclusion criteria and improvements in myocardial protection led to the revival of the technique, and the initial good results reported by Hitchcock and colleagues [9] prompted others to use it in selected patients [10–12]. Dion and coworkers [12] suggested that a saphenous vein patch might be superior to autologous pericardium because of its potential fibrinolytic activity.
The aim of the present study was to review the mid- and long-term outcomes of LMCA ostial reconstruction with fresh autologous pericardium or saphenous vein onlay patch at our center.
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Patients and Methods
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The study group consisted of 15 patients with isolated LMCA stenosis referred for surgical ostial reconstruction, of 8000 patients who underwent surgical coronary revascularization at our center between January 1993 and June 2003. There were 11 women (73%) and 4 men of 53 ± 8 years (mean ± SD) at operation. Background diseases included hypertension in 80%, hyperlipidemia in 40%, and diabetes mellitus in 13%; 33% of the patients were obese, and 33% were smokers. Thirteen percent had a family history of coronary artery disease (CAD; Table 1).
Coronary angiography in all cases revealed critical isolated LMCA stenosis with no additional significant disease in the coronary tree. Preoperative transesophageal echocardiography (TEE) or intravascular ultrasound (IVUS) was performed to evaluate the location of the stenosis (proximal, distal or both) and the degree of calcifications (Fig 1). Only one patient had visible LMCA calcification on the preoperative TEE study. Indications for operation were unstable or recent angina pectoris in 14 patients and severe aortic stenosis in 1. Additional procedures included aortic valve replacement (AVR) in 1 patient.
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Figure 1. A representative angiogram and intravascular imaging of the stenotic proximal left main artery (arrow). The ultrasound imaging reveals a reference left main artery (left panel) of 15.4 mm2 cross sectional area with a lumen area of 5.2 mm2 at the lesion site (right panel).
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Operative Technique
Surgery was performed using standard cardiopulmonary bypass with mild or moderate hypothermia (28 to 32°C). For myocardial preservation, cardiac arrest was induced with a cold blood cardioplegic solution delivered antegradely and retrogradely, except in one patient in whom antegrade cold intermittent cardioplegia was used. The left ventricle was vented by a catheter advanced through the right superior pulmonary vein. After the patient was placed on cardiopulmonary bypass and aortic cross clamping was completed, the main pulmonary trunk was encircled with a nylon tape and retracted laterally. The pericardial fat was carefully removed from the LMCA to improve visibility. A right aortic incision was used, beginning on the interior medial wall of the aorta and directed into the ostium of the LMCA. Using Pott's scissors, the surgeon extended the incision through the LMCA to the bifurcation of the circumflex and left anterior descending artery branches (Fig 2A). Ostial reconstruction was performed with a fresh autologous pericardial patch in 9 patients, and a fresh saphenous vein that was tailored as a patch in 6. Fine sutures (8-0 Prolene) were used to create a new funnel-shaped LMCA segment (Fig 2b).
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Figure 2. Anterior approach. (A) Main pulmonary trunk is encircled with nylon tape and retracted laterally. The pericardial fat is carefully removed from the LMCA and anterior curved aortotomy is performed. The incision is extended to the bifurcation of the circumflex and left anterior descending artery branches. (B) For the reconstruction, fresh autologous pericardium or a saphenous vein patch is used to create a new funnel-shaped LMCA segment. (Ao = aorta; LCC-RCC = left coronary cusp-right coronary cusp; LMCA = left main coronary artery; MPA = main pulmonary artery.)
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Operative Findings
Fibrous narrowing of the coronary ostia was noted in 14 patients, involving the proximal part of the LMCA in all of them, as well as the distal part in 4. None of these patients had significant calcification. The remaining patient, a 69-year-old woman, was referred for AVR, and also had severe LMCA stenosis. After the aorta had been opened and the pericardial fat exposed, calcification was seen in the LMCA. Since this woman had Raynaud's syndrome and had undergone recent left breast mastectomy and irradiation, we decided to continue with the surgical repair and to avoid using the left internal mammary or radial artery. Once the LMCA plasty had been completed, the aortic valve was replaced in standard fashion.
Postoperative Treatment and Follow-Up
In the last 8 patients the surgical reconstruction was evaluated in the operating room with TEE after the patients had been weaned from cardiopulmonary bypass. All TEE studies were done with a 5-MHz multiplane probe (Sonos 2000; Hewlett-Packard, Palo Alto, CA).
After surgery, all patients were prescribed wafarin for 6 months to maintain an international normalized ratio of 2.0 to 3.0. During follow-up, all patients underwent imaging of the reconstructed LMCA with TEE or coronary angiography and IVUS.
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Results
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Early Results
There were no technical failures. All postoperative TEE examinations revealed a wide open left main artery with a physiologic laminar flow pattern. None of the patients had a perioperative myocardial infarction. One patient required re-exploration for bleeding, and recovered uneventfully afterwards. There were no other significant postoperative complications. Patients were discharged from the hospital after a mean of 6.5 ± 2 days. There were no early deaths.
Late Results
The duration of follow-up ranged from 4 to 120 months (mean 55 ± 39 months) and was complete for all patients. No patient had any cardiac-related event during follow-up or required repeated coronary intervention. There were no late deaths.
Coronary angiography and IVUS were performed during follow-up in 2 patients because of nonspecific chest discomfort. In both cases, the LMCA was found to be wide open and there were no signs of patch calcifications (Fig 3). The other 13 patients underwent TEE, which demonstrated a wide-open LMCA (range 3 to 8 mm, mean 5.7 ± 1.3), normal flow pattern by pulsed-wave Doppler, and no aneurysmal dilatation or calcifications of the onlay patch. Left ventricular function remained normal (grade 1) in 14 patients, and improved from grade 3 to grade 2 in 1.
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Figure 3. The left main angiogram at follow-up after left main surgical angioplasty demonstrating a widely patent left main of 5.3-mm diameter (arrows).
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Comment
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Isolated stenosis of the LMCA is relatively rare. In the series reported by Loop and colleagues [1], isolated LMCA stenosis was noted in only 0.7% of the cohort of patients operated upon for coronary disease.
Coronary artery bypass grafting (CABG) is the most common treatment, and is associated with excellent short- and long-term outcomes [13]. However, it may lead to occlusion of the LMCA, restores only retrograde perfusion of the myocardium proximal to the graft anastomosis, can result in competitive flow, and consumes bypass material. Surgical reconstruction of the LMCA avoids these potential drawbacks, and in addition, does not preclude percutaneous coronary intervention for the distal coronary tree if necessary at a later stage. It can also be useful in patients with inadequate conduits or intramyocardial coronary arteries.
Technically, we used the anterior approach, which provides excellent exposure of the left main stem all the way to its bifurcation (Fig 2). By encircling the main pulmonary artery with nylon tape and retracting it laterally, we were able to avoid the aggressive transpulmonary approach [14]. We also tried to exclude patients with heavily calcified left main and distal LMCA disease, which are considered risk factors for early failure [12].
Intraoperative TEE proved to be a useful tool for patient selection for the procedure. In 3 patients, TEE demonstrated significant calcification that was not seen in the preoperative coronary angiogram.
Dion and coworkers [12] suggested that the saphenous vein onlay patch, owing to its potential fibrinolytic activity, might be preferable to autologous pericardium. In our series, we used fresh (nonglutaraldehyde treated) autologous pericardium in 9 of 15 patients. There were no early failures, and follow-up of the reconstructed segments revealed no aneurysmal dilatation or significant new calcification. We found the pericardium easy to use, and even superior to the saphenous onlay patch in cases in which the saphenous vein was narrow or diseased.
There have been some attempts to use magnetic resonance imaging [15, 16] or spiral computed tomography [17] as noninvasive tools for follow-up assessment of reconstruction patency. Both were found to have limited accuracy. We previously reported [18] that TEE is an accurate semi-invasive tool for the assessment, follow-up and confirmation of the results of left main coronary artery patch angioplasty. With the use of TEE, LMCA anatomy and patency can be optimally delineated.
In our series, no postoperative myocardial viability tests were performed. Stress echocardiogram may be advisable in these patients to assure coronary flow reserve.
In conclusion, surgical reconstruction of the LMCA is safe and effective for the treatment of isolated left main stenosis. The use of fresh autologous pericardium appears to be as safe as a saphenous vein onlay patch. Neither method in our series was associated with postoperative aneurysmal dilatation or calcifications.
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References
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Abstract
Introduction
