Coronary artery bypass grafting in patients on chronic hemodialysis: diabetic nephropathy versus nondiabetic nephropathy

Coronary Artery Bypass Grafting in Dialysis-Dependent Patients - Key Peri-Operative Considerations

Cardiovascular disease represents the leading cause of mortality in dialysis-dependent (DD) patients, with the great majority of these patients afflicted by severe coronary artery disease. As rates of end-stage renal disease increase worldwide, DD patients represent a growing proportion of the coronary artery bypass grafting (CABG) cohort. Yet, these patients are complex, with crucial changes in their haemodynamic and physiologic profiles that complicate revascularisation surgery. First, this comprehensive literature review explores the outcomes and prognostic factors for DD patients undergoing CABG. We then summarise the intricacies relating to important peri-operative decisions such as use of cardio-pulmonary bypass and choice of conduit.

Results of Isolated Valve Replacement in Hemodialysis Patients

Frequent bleeding complications and poor long-term results have been reported after valve replacement in hemodialysis patients. We use mainly bileaflet mechanical valves with low-dose warfarin therapy (target international normalized ratio, 1.8–2.0) in such cases. Data of 27 hemodialysis patients undergoing isolated valve replacement from 1993 to 2002 were retrospectively analyzed. Bileaflet mechanical valves were selected in 23 patients and bioprostheses in 4. Those with mechanical valves were treated with mild anticoagulation therapy. There were 3 (11.1%) early deaths due to ischemic colitis, interstitial pneumonia, and ventricular arrhythmia. There were 3 late deaths and 5 bleeding complications during follow-up. The overall survival rate was 85.2% at 3 years and 72.9% at 5 years. The survival rate of patients with mechanical valves was 82.6% at 3 years and 76.7% at 5 years. One patient with a bioprosthesis experienced structural valvular deterioration after 3 years. The results demonstrate an acceptable long-term outcome. A bileaflet mechanical valve managed with mild anticoagulation therapy is a reasonable strategy for hemodialysis patients.

Influence of hemodialysis duration on mid-term clinical outcomes in hemodialysis patients with coronary artery disease after drug-eluting stent implantation

Accelerated atherosclerosis in prolonged maintenance hemodialysis (HD) has been recognized; however, whether HD duration is associated with poor clinical outcome in HD patients with coronary artery disease (CAD) after drug-eluting stent (DES) implantation is unknown. We evaluated the impact of HD duration on clinical outcomes in HD patients with CAD after DES implantation. Between April 2007 and December 2012, 168 angina pectoris patients (320 de novo lesions) on HD were treated with DES. Major adverse cardiovascular events (MACE) and target lesion revascularization (TLR) were investigated at 3 years according to the HD duration (≤ 3 years, 83 patients; >3 years, 85 patients). The incidence of MACE was significantly higher in the long HD duration group (25.3 vs. 50.6 %; P = 0.001). Especially, sudden cardiac death (SCD) was significantly higher in the long HD duration group (3.6 vs. 16.5 %; P = 0.006). On the other hand, the rates of TLR were similar between the two groups (12.0 vs. 14.1 %; P = 0.69). Cox's proportional hazard analysis revealed that HD duration (HR 1.08 per year, 95 % CI 1.03-1.13, P = 0.002), β-blocker use (0.28, 0.17-0.46, P < 0.001), and diabetes mellitus (2.10, 1.23-3.56, P = 0.007) were independent predictors of MACE. Longer HD duration did not affect TLR; however, SCD was significantly higher in the long HD duration group.

Outcomes following cardiac surgery in patients with preoperative renal dialysis

A best evidence topic in cardiac surgery was written according to a structured protocol. The question addressed was that whether patients who are dependent on chronic dialysis have higher morbidity and mortality rates than the general population when undergoing cardiac surgery. These patients often require surgery in view of their heightened risk of cardiac disease. Altogether 278 relevant papers were identified using the below mentioned search, 16 papers represented the best evidence to answer the question. The author, journal, date and country of publication, patient group studied, study type, relevant outcomes, results and study weaknesses were tabulated. Dialysis-dependent (DD) patients undergoing coronary artery bypass grafting (CABG) or valve replacement have higher morbidity but acceptable outcomes. There is some evidence to show that outcomes after off-pump coronary artery bypass grafting (OPCAB) are better than after on-pump coronary artery bypass grafting (ONCAB) and that results are worse in DD patients with diabetic nephropathy. Patients undergoing combined procedures have a higher mortality.

Aortic valve prosthesis selection in dialysis patients based on the patient's condition

Previous studies have examined outcomes in dialysis patients undergoing cardiac surgery. However, only a few studies have solely focused on outcomes after aortic valve replacement (AVR). This study aimed to clarify independent predictors of the long-term survival of dialysis patients with AVR and to determine whether a mechanical valve or bioprosthesis is suitable based on the patient's condition. A total of 38 consecutive dialysis patients who underwent AVR at our institute were reviewed (mean age 69.1 ± 9.4 years). There were 23 bioprostheses and 15 mechanical valve replacements. The operative mortality and the long-term survival were not different between the bioprosthesis and the mechanical valve group (13.0 vs. 13.3%). The significant multivariate predictors for long-term survival were concomitant coronary artery bypass grafting (CABG) and prosthesis size. Valve types and age at operation did not affect long-term survival. Five-year survival of patients with small prosthetic valves and concomitant CABG was 0%. When the patient's quality of life is taken into account, it may be appropriate to use a bioprosthesis in a dialysis patient with a small annulus and concomitant CABG even if the patient is young.

Is diabetic nephropathy a predicted risk factor?--Kaplan-Meier and multivariate analysis of confounding risk factors in off-pump coronary artery bypass grafting for chronic dialysis patients

BACKGROUND

The purpose of this study was to investigate the preoperative risk factors of performing off-pump coronary artery bypass grafting (OPCAB) in patients on chronic dialysis.

METHODS AND RESULTS

The 41 consecutive patients on chronic dialysis who underwent OPCAB from February 2000 to April 2006 at the National Cardiovascular Center were studied retrospectively. Of them, 29 had diabetic nephropathy (DN group) and the remaining 12 did not (NDN group). There were significant differences in the duration of dialysis before surgery (9.1 +/-7.5 years in NDN vs 4.2 +/-5.5 years in DN, P=0.028) and low cardiac function (left ventricular ejection fraction <30%), which was recognized only in the DN group (7/29, P=0.048). The early mortality rate was 6.9% (2/29) in the DN group and 16.7% (2/12) in the NDN group (P=0.349). The actuarial survival rates in the DN group were 85% at 1 year, 45% at 3 years, and 30% at 5 years, whereas in the NDN group they were 71%, 49%, and 49%, respectively (P=0.789). arteriosclerosis obliterans (ASO) and age (>65 YEARS) were independent risk factors of late death.

CONCLUSIONS

For patients on chronic dialysis ASO and aging were predicted risk factors for OPCAB, whereas diabetic nephropathy was not.

Impact of concomitant cardiac procedure on coronary artery surgery in hemodialysis-dependent patients

OBJECTIVE

Coronary artery bypass grafting (CABG) in hemodialysis-dependent patients is associated with high mortality and morbidity rates. This retrospective study was undertaken to identify the risk factors for in-hospital mortality for hemodialysis-dependent patients.

METHODS

Subjects included 87 consecutive hemodialysis-dependent patients (81 men and 6 women), aged 47-82 years (mean age, 65 years), who underwent CABG. Operative procedures included CABG alone (n=77) and CABG with valve replacement, repair, or the Dor procedure (n=10). Thirty-one perioperative risk factors were subjected to univariate and multivariate analyses to identify the risk factors for hospital death.

RESULTS

The overall in-hospital mortality rate, including operative death, was 14.9% (13/87). Univariate analysis showed the following 7 risk factors to be statistically significant predictors of hospital death: age > or = 70 years, a concomitant cardiac procedure, left ventricular ejection fraction <30%, left ventricular end-systolic volume index >70 ml/m2, a left main lesion, emergency/urgent surgery, and anemia (hemoglobin <10 mg/dl) (p<0.05 for each predictor). Multivariate logistic regression analysis confirmed that a concomitant cardiac procedure (chi-squared = 17.080, p=0.013) and age > or = 70 years (chi-squared = 9.112, p=0.019) are statistically significant independent risk factors for hospital death.

CONCLUSION

A concomitant cardiac procedure and age > or = 70 years were identified as significant independent risk factors for hospital mortality after CABG for hemodialysis-dependent patients. These preoperative risk factors may help in predicting operative risks and improving clinical outcomes in hemodialysis-dependent patients undergoing CABG.

Multiple Risk Assessment of Cardiovascular Surgery in Chronic Renal Failure Patients

BACKGROUND

Chronic renal failure is a major risk factor in cardiovascular surgery. We evaluated results of cardiovascular surgery in chronic renal failure patients (s-creatinine > 200 micromol/L or established dialysis) at our center from 1990 to 2000.

METHODS

One hundred and six chronic renal failure patients underwent cardiovascular surgery (56 coronary artery bypass operations, 25 valve replacements with or without coronary bypass, and 25 other major cardiovascular operations [8 thoracic aorta, 10 abdominal aorta, 7 other]). Matched controls were selected (n = 106) based on age, sex, year, and type of operation and occurrence of diabetes.

RESULTS

There were 88 men and 18 women and mean age was 64 +/- 10 years (standard deviation). Demographics did not differ between chronic renal failure and control patients, except for hypertension (more prevalent in chronic renal failure group, p < 0.05). Intraoperative hemorrhage, perfusion and ischemia time, and reoperation did not differ between groups. Chronic renal failure patients received more transfusions of red blood cells, plasma, and platelets (p < 0.02). Ventilation support (27.6 +/- 59.3 hours), intensive care unit stay (7.7 +/- 8.3 days), and hospital stay (12.3 +/- 10.5 days) were longer (p < 0.02). Early mortality was 16% versus 6.6% (p = 0.04) and 5-year mortality was 79% versus 39% (p < 0.05) for chronic renal failure and control patients, respectively. Independent preoperative risk factors of mortality for chronic renal patients were age greater than 70 years (relative risk = 2.32, p = 0.001), chronic obstructive pulmonary disease (relative risk = 2.59, p = 0.001), diabetes (relative risk = 1.80, p = 0.037), and dialysis (relative risk = 2.03, p = 0.005).

CONCLUSIONS

Chronic renal failure patients suffered more postoperative complications and had substantially increased short-term and long-term mortality rates. Independent preoperative mortality risk factors for chronic renal failure patients were age, chronic obstructive pulmonary disease, diabetes, and chronic dialysis.