Early and long term results of coronary artery bypass grafts in patients with dialysis dependent renal failure

Abstract

Objective: Coronary artery disease is the main cause of mortality and morbidity in patients on renal therapy replacement. The aim of this study was to define peri-operative risk and long term results of coronary artery bypass grafts (CABG) in dialysis patients.

Methods: this retrospective study included 82 patients in chronic dialysis who underwent CABG between 1978 and 1997. The mean age was 61+/-10 years (range 28-81 years), 84% of the patients were male and the average duration of dialysis was 57 months (range 1-148 months). Combined procedures were carotid endarterectomy in one case, left ventricular aneurysm resection in one and valvular replacement in 10 (nine aortic and one mitral replacements). The operation was elective in 42 patients (51 %) and urgent in the others. Previous myocardial infarction was found in 37 patients (45%) and left ventricular ejection fraction (LVEF) at less than 45% in 15 patients (18%); 23 patients (28%) were in NYHA class III or IV and regarding angina functional status, 77% in CCS class 3 or 4. Follow-up was complete. Statistical analysis included 30 and pre and peri-operative data. Statistical analysis used Chi-square analysis or Fisher's exact test, and the Mann-Whitney test when appropriate. The estimated probability of survival, including postoperative mortality, was calculated by the method of Kaplan-Meyer, and the Log-Rank test used to compare the results.

Results: the hospital mortality was 14.6 % (n = 12). Ischemic time and ECC time were significantly lengthened in dead patients (P = 0.01). Moreover, use of internal mammary artery was directly related to lower hospital mortality (P = 0.02). For previous myocardial infarction, LVEF at less than 45%, diabetes and combined procedure, a P-value of < or = 0.1 was calculated. The follow-up ranged from 1 to 140 months (mean 36 months). There were 39 late deaths. The survival rates (included hospital mortality) were 71+/-5%, 56+/-6% and 39+/-6% at 1, 3 and 5 years, respectively. All surviving patients improved their functional status and had symptomatic relief. Statistical analysis showed significant difference in favor of long term survival for patients younger than 60 years, LVEF > 45% and NYHA class I or II.

Conclusion: these data confirm that CABG in patients with renal replacement therapy is associated with an high operative and long term mortality. However it allows an improvement of functional status, and so, let possible duration of dialysis. It may be expected that more active prevention and detection of coronary disease might improve these results.