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Ann Thorac Surg 2005;79:88-92
© 2005 The Society of Thoracic Surgeons
a Department of Cardiology
b Department of Thoracic and Cardiovascular Surgery, The Tel Aviv Sourasky Medical Center and The Sackler Faculty of Medicine, Tel Aviv University
c The Catheterization Laboratories, Assouta Medical Center, Tel Aviv, Israel
Accepted for publication June 21, 2004.
* Address reprint requests to Dr Herz, Department of Cardiology, The Tel Aviv Sourasky Medical Center, 6 Weizmann St, Tel Aviv 64239, Israel (E-mail: isach{at}tasmc.health.gov.il).
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Abstract |
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METHODS: From June 2002 to June 2003, 386 consecutive patients underwent myocardial revascularization of the left anterior descending coronary artery territory, 130 by Cypher and 256 by OPCAB. After matching for age, sex, and extent of coronary artery disease, two groups (each with 94 patients) were used to compare the two revascularization modalities. The two groups were similar; however, old myocardial infarction and intraaortic balloon pump were more prevalent in the OPCAB group, and prior percutaneous transluminal coronary angioplasty was more prevalent in the Cypher group.
RESULTS: The number of coronary vessels treated per patient in the two groups was similar (1.54 versus 1.34, OPCAB and Cypher, respectively; not significant). Mean follow-up was 18 months. Thirty-day mortality was 1% in the OPCAB group and 0% in the Cypher group. There was one late death in each group. Angina returned in 31% of the Cypher group and in 11% of the OPCAB group (p = 0.001). There were nine reinterventions in the Cypher group: seven coronary angioplasties (including two to the left anterior descending coronary artery) and two surgical interventions. There were two reinterventions (percutaneous transluminal coronary angioplasty) in the surgical group (p = 0.042).
CONCLUSIONS: Despite the higher risk profile of patients treated with OPCAB, their clinical outcome is better. A longer and more complete angiographic follow-up is required to determine the role of drug-eluting stents in left anterior descending coronary artery revascularization.
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Introduction |
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TopAbstractIntroductionPatients and MethodsResultsCommentReferences |
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Several reports of nonrandomized studies comparing percutaneous coronary angioplasty (PTCA) and CABG have shown a trend to improved survival with CABG in patients with multiple vessel disease and proximal LAD stenosis [4–6]. Revascularization for isolated LAD disease using PTCA, stent, or left internal mammary artery (IMA) to LAD resulted in similar occurrence of adverse events and mortality, and similar actuarial 2-year survival. However, repeat procedures were required less often after left IMA to LAD (30%, 24%, and 5% for the PTCA stent and left IMA to LAD, respectively; p < 0.001) [7]. In a later report with more liberal use of stents for the proximal LAD, the only advantage of left IMA to LAD was the lower rate of reinterventions during the 42-month follow-up period [8].
Significant reduction of restenosis and reintervention was recently reported with the introduction of drug-eluting stents (DES) [9]. Most patients with proximal LAD stenosis referred for CABG in our center are operated on using off-pump coronary artery bypass grafting (OPCAB). We therefore decided to compare our initial clinical results with DES to the LAD with those of left IMA to LAD using OPCAB.
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Patients and Methods |
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TopAbstractIntroductionPatients and MethodsResultsCommentReferences |
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Preoperative characteristics of OPCAB and Cypher patients were similar. However, more of those treated surgically with OPCAB were older than 70 years of age (40% versus 19%). The OPCAB patients also had increased prevalence of left main and triple-vessel disease (21% and 62% versus 2% and 30%, respectively).
To control for these differences between OPCAB and Cypher patients, we decided to compare results between the two treatment modalities only after matching for age, sex, and extent of coronary artery disease involvement (Table 1). Each of the two matched groups thus created contained 94 patients. Preoperative characteristics of patients in both groups are depicted in Table 2.
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About 50% of the surgical patients were operated on without extracorporeal circulation (OPCAB). Most of the decisions to perform open-heart surgery are made intraoperatively. Off-pump CABG is preferred in a patient older than 70 years of age, patients with a calcified aorta, and patients with damage to other systems (kidneys, lungs, liver, peripheral vascular disease, and so forth), and CABG with pump is preferred in patients with especially small coronary arteries, atheromatotic, calcified disease, or diffuse disease that requires four or more anastomoses.
In the PCI group, stent implantation was performed after balloon angioplasty dilatation. All patients received aspirin (325 mg daily) before and after the procedure, and clopidogrel (a loading dose of 300 mg the day before the procedure, and 75 mg daily for 3 months thereafter). During the procedure all patients were treated intravenously with heparin. Platelet glycoprotein IIb/IIIa inhibitors (abciximab) were used only in 8 patients of the PCI group. In most patients, only one Cypher was used for the LAD. However, more than one stent was used if required (long lesion, dissection, or bifurcation). Drug-eluting or bare stents or PTCA were used for non-LAD lesions. Acute myocardial infarction (within the previous 48 hours), poor ejection fraction (<0.25), left main disease, calcification or thrombus within the LAD, long lesions (>30 mm) and bifurcation lesions were major criteria for exclusion of patients from the group treated with stents to the LAD. On the other hand, patients with diabetes or ostial LAD lesions were not excluded.
In the OPCAB group, all IMAs were dissected as skeletonized vessels. To achieve left-sided (LAD + circumflex) arterial revascularization, we used either the right IMA (in situ or as composite T graft) or the radial artery (composite T graft) in patients requiring more than one graft (left IMA to LAD).
In 24 of 27 patients treated with bilateral IMA grafting, right system (posterior descending coronary artery) revascularization was performed with saphenous vein grafts. The distal radial artery was used for right coronary artery revascularization in patients treated with the left internal thoracic artery and radial artery (composite T graft).
To decrease the risk of spasm of the arterial grafts, we treated all OPCAB patients with a high-dose intravenous infusion of isosorbide dinitrate (Isoket; 4 to 20 mg/h) during the first postoperative 24 to 48 hours [10]. Systolic blood pressure was maintained greater than 100 to 120 mm Hg. From the second postoperative day, all radial artery patients were treated with calcium-channel blockers (diltiazem 90 to 180 mg/d orally).
Statistical Analysis
Data are expressed as mean ± standard deviation or proportions, as appropriate. The two groups were matched for age, sex, and extent of coronary artery disease. The 
2 test and Fisher exact test were used to compare groups regarding discrete variables. Two-sample Student's t test was performed for continuous variables. Multivariable logistic regression analysis was used to evaluate risk factors for early return of angina and reintervention. Odds ratio and 95% confidence interval were given. Kaplan-Meier curves were used to describe angina-free survival and reintervention-free survival. Log-rank test was used to compare event-free survival between groups. All analyses were performed by SAS System for Windows, release 8.02 (SAS Institute, Cary, NC).
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Results |
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TopAbstractIntroductionPatients and MethodsResultsCommentReferences |
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The average number of coronary vessels treated was similar (1.54 versus 1.34 in the OPCAB and Cypher groups, respectively; not significant). However, more patients in the Cypher group received only one stent, and more in the OPCAB group had revascularization of three vessels (Table 3). Thirty-day mortality was 1% in the OPCAB group and 0% in the Cypher group. Mean follow-up was 18 months. There was one late death in each group. Angina returned in 29 patients (31%) of the Cypher group compared with 10 (11%) in the OPCAB group (p = 0.001). There were nine reinterventions in the Cypher group: seven coronary angioplasties (including two to the LAD) and two surgical interventions. There were two reinterventions (PTCA) in the surgical group (p = 0.05, Cypher versus OPCAB; Table 4).
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The regression model showed that after controlling for the above risk factors, the only independent predictors for reangina were treatment with PCI (Cypher group: odds ratio, 5.39; 95% confidence interval, 2.17 to 13.39) and congestive heart failure (odds ratio, 0.11; 95% confidence interval, 0.027 to 0.498). Treatment with PCI was also the only significant predictor for reintervention (odds ratio, 7; 95% confidence interval, 1.27 to 38.4).
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Comment |
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TopAbstractIntroductionPatients and MethodsResultsCommentReferences |
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After a 12-month follow-up, which is a long enough period for the development of in-stent restenosis [11], survival was similar. However, a significant portion of the Cypher group (31%) experienced early return of angina, and 11% required reintervention. These occurrences of reangina and reintervention were significantly higher than those of the OPCAB group, and multivariable analysis showed that the only independent predictor of reangina and reintervention is the revascularization technique used (ie, the use of PCI).
Despite the above unfavorable observations, our study does not contradict previous reports suggesting decreased restenosis rate with DES [9, 12, 13]. Only two of the nine reinterventions were performed in the LAD territory (after Cypher implantation). One, an 83-year-old patient who probably experienced subacute thrombosis after the initial procedure, was referred for recatheterization because of angina recurrence and was treated successfully with re-PTCA; the other patient was a 46-year-old man who was treated with two Cyphers to the LAD for in-stent restenosis. He had in-segment restenosis in the LAD, and was operated on successfully 6 months after the PCI. All other reinterventions were performed in vessels that had not been treated during the initial PCI.
The number of patients requiring reinterventions was far too small to draw any conclusion about the etiology underlying the reintervention. However, we observed that despite similar extent of coronary involvement and similar mean number of vessels treated, more patients in the Cypher group underwent revascularization of only one vessel and more in the OPCAB group had revascularization of three vessels. This, together with the fact that only two of the reinterventions were performed to the Cypher-treated LAD, may suggest that a major cause of reangina and reintervention in the Cypher group is incomplete revascularization rather than early failure of the DES.
The study population of the surgical group is not typical for the kind of patients currently referred for CABG in our institution. It contains a relatively high number of patients with single-vessel disease and relatively few patients with left main or three-vessel disease, or patients older than 70 years. Accordingly, a high proportion of the OPCAB patients were treated with single graft (IMA to LAD). This explains the relatively low number of grafts per patient (1.54), and is the result of the matching protocol.
Despite the fact that reangina and reintervention rate of the surgical group was significantly lower than that of the PCI group, occurrence of reangina in 11% of the patients after OPCAB after 18 months' follow-up was also higher than our reported rate of reangina [14]. This can also be explained by the relatively low number of grafts per patient that is a result of the selection protocol.
However, all vessels with significant (>70%) stenosis were treated, and in the 4 patients with positive thallium single-photon emission computed tomographic imaging who were catheterized postoperatively, patent grafts were observed in 2. The other 2 underwent PCI, one to a new coronary lesion and the other to the anastomotic site (right coronary artery).
This is a retrospective observational follow-up study. The groups were not matched prospectively preoperatively. We tried to compensate for this limitation by our matching protocol, which is based on the extent of diseased vessel involvement. However, other important covariates (mainly technical), such as vessel diameter, lesion length, occluded or thrombosed vessels, and bifurcation lesions, were not included in the analysis. These technical factors may affect restenosis, reangina, and reintervention in the PCI group, but are less important in the surgical group. We believe that they could have been included in the study had the patients been evaluated prospectively.
In conclusion, despite the higher risk profile of patients treated with OPCAB, their clinical outcome is better. Early results of Cypher to the LAD are encouraging, with an acceptable reintervention rate in the LAD territory. The use of DES to other vessels, with the aim of complete revascularization, might further reduce reangina and reintervention rate. A larger and more complete angiographic follow-up is required to determine the role of DES in LAD revascularization.
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References |
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This article has been cited by other articles:
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  Y. Ben-Gal, Y. Moshkovitz, N. Nesher, G. Uretzky, R. Braunstein, A. Hendler, E. Zivi, I. Herz, and R. Mohr Drug-Eluting Stents Versus Coronary Artery Bypass Grafting in Patients with Diabetes Mellitus Ann. Thorac. Surg., November 1, 2006; 82(5): 1692 - 1697. [Abstract] [Full Text] [PDF]
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