**12. Conclusion**

bleeding. [230] Intraoperative blood loss is a major cause of post-operative bleeding from depleted coagulation factors and hemodilution. Consideration should be given to preoperative antiplatelet therapy including aspirin and clopidogrel. A low platelet count and other medical conditions that adversely affect the coagulation process should be carefully investigated.

Redo CABG for coronary bypass graft failure is not favoured by cardiologists and surgeons alike, due to the higher morbidity and mortality compared with primary CABG. Reported intraoperative mortality rates are 5.8-9.6%. [231] Other major complications include stroke (1.4-3.2%), non-fatal MI (3.0-9.6%), renal failure (2.4-11%) and post-operative bleeding (2.7-4.4%). [217,223] Following redo CABG, survival is 75–90% and 55–75% at 5- and 10-year

*Redo CABG versus PCI -* Available data comparing the outcomes of PCI to redo CABG in patients with prior CABG is limited. Initial studies evaluating BA versus CABG noted comparable long-term results except for a much higher rate of repeat revascularization in the BA group (BA 64% vs. redo CABG 8%). [232] Multivariate analysis identified age > 70 years, left ventricular ejection fraction < 40%, unstable angina, number of diseased vessels and diabetes mellitus as independent correlates of mortality for the entire group. Direct compari‐ son between redo CABG and PCI was performed in the AWESOME trial. A total of 142 patients with refractory post-CABG ischemia and at least one of five high-risk features (i.e. prior openheart surgery, age >70 years, left ventricular ejection fraction <35%, MI within seven days or intraaortic balloon pump required) amandable for either PCI or redo CABG were randomized. [17] Arterial grafts were used in 75% of redo CABG procedures and stents in 54% of PCI (approximately one-half with BMS). In-hospital mortality was higher after redo CABG (8% vs. 0%). At 3 years, there was no significant difference in overall patient survival (redo CABG 71% vs. PCI 77%), but there was a nonsignificant increase in survival free of unstable angina in the CABG group (65% vs. 48%). In the much larger retrospective observational study from the Cleveland Clinic of 2191 patients with prior CABG who underwent multivessel revasculari‐ zation between 1995 and 2000 were evaluated. [233] A total of 1487 had redo CABG and 704 underwent PCI (77% with at least one stent). No difference was observed in 30-day mortality with redo CABG compared to PCI (2.8% vs. 1.7%) but as expected periprocedural Q wave MI occurred more often after redo CABG (1.4% vs. 0.3%). At 5-years follow-up, cumulative survival was similar with redo CABG and PCI (79.5% vs. 75.3%). After adjustment, PCI was associated with a nonsignificant increase in mortality risk (hazard ratio 1.47, 95% CI 0.94-2.28). The major predictors of mortality were higher age and lower LVEF, not the method of revascularization. Importantly, the choice of treatment strategy was largely determined by coronary anatomy wherein the most important factors to perform redo CABG were: 1) more diseased or occluded grafts, 2) absence of a prior MI, 3) lower left ventricular ejection fraction, 4) longer interval from first CABG (15 vs. 6 years), 5) more total occlusions in native coronary

arteries, and 6) the absence of a patent mammary artery graft.

In diabetic patients with post-CABG angina, the outcomes after repeat revascularization were evaluated in an observational study in which 1123 such patients underwent PCI (75% BA, 25% stent palcement) and 598 underwent redo CABG. [234] Redo CABG was associated with increased in-hospital mortality (11.2% vs. 1.6%) and stroke (4.7% vs. 0.1%). At 10 years, there

follow-up, respectively. [231]

216 Artery Bypass

Patients with prior CABG remain at risk for future cardiac events, including graft failure. Stable patients with recurrence of angina following CABG can be treated medically for their symp‐ toms and risk factor reduction. In all patients with coronary heart disease aggressive risk factor reduction is recommended which includes aspirin, treatment for hypertension and serum lipids, avoidance of smoking, and controlling serum glucose in diabetic patients. Evaluation for ischemia is as in other patients with stable angina without prior CABG. However, early diagnostic angiography is suggested as the different anatomic possibilities, i.e. graft stenosis or progression of native vessel disease in nonbypassed vessels can lead to recurrent ischemia. Revascularization of graft failure either by PCI or redo CABG is associated with worse acute and long-term outcomes compared to patients without prior CABG. The choice of treatment modality is influenced by clinical and angiographic characteristics. When multiple grafts are occluded or the graft or native coronary artery appears unsuitable for PCI, surgery should be favoured. The target for PCI is the body of the coronary artery of the arterial graft while freshly occluded SVG or the anastomosis itself should be targeted due to the risk of embolization or perforation. Whether specific stent platforms, polymers or drugs are more appropriate in SVG and arterial graft lesions has not been addressed at this time. Moreover, the role of various surgical techniques for graft revascularization, such as off-pump and minimal invasive CABG also remain unclear. Finally, factors including disease status of the native vessel, and patient characteristics such as left ventricular function, renal failure, diabetes and advanced age, as shown in our multivariate analysis are of influence on outcomes. Future prospective studies in the medical and invasive treatment of graft failure are therefore warranted. Those studies together with our growing understanding of the pathobiology of arterial and vein grafts will ultimately result in practical patient-tailored therapeutic strategies to enhance graft function and control intimal hyperplasia and accelerated atherosclerosis.

[11] Kolessov VI. Mammary artery-coronary artery anastomosis as method of treatment

Treatment of Coronary Artery Bypass Graft Failure

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