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

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.

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.

The impact of non-dialysis-dependent renal dysfunction on outcome following cardiac surgery

BACKGROUND

We evaluated the results of different types of cardiovascular surgery in patients with chronic renal failure (CRF) (serum creatinine ≥2 mg/dL) who were not dialysis-dependent.

METHODS

Eighty-two patients who presented with non-dialysis-dependent CRF were retrospectively evaluated. Patients in Group 1 (n = 12) underwent valvular surgery, those in Group 2 (n = 58) underwent coronary artery bypass grafting (CABG), and those in Group 3 (n = 12) underwent combined CABG and valvular surgery.

RESULTS

The demographics were similar among the groups. Cardiopulmonary bypass and aortic cross-clamping times were shorter (P < .01), the use of blood and blood products was less, and the mechanical ventilation time and hospital stay were shorter in Group 2 in comparison to the other groups (P < .01). There were 4 (6.9%) early mortalities in Group 2. Late mortalities occurred in 4 (33.3%), 16 (27.6%), and 6 (50%) patients from Groups 1, 2, and 3, respectively. Cox regression analysis revealed that age, the presence of a preoperative cerebrovascular accident, the presence of a left main coronary lesion, preoperative blood urea nitrogen level, and the use of blood and blood products were independent risk factors for early mortality. High Euroscore, cerebrovascular accident, the use of platelet suspension, longer ventilation support times, and combined CABG and valvular surgery were independent risk factors for late mortality.

CONCLUSIONS

Morbidity and survival seemed to be more dependent on preoperative patient characteristics than the type of surgery in this group of patients. Combined CABG and valvular surgery was a risk factor for late mortality.

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.

Even moderate chronic renal failure is associated with impaired acute and long-term outcome after coronary angioplasty

End-stage renal failure requiring maintenance haemodialysis is known to be a strong independent predictor of mortality and complications after coronary interventions. In contrast, data about the outcome of patients with moderate chronic renal failure is very limited and was therefore evaluated in this study in patients with coronary angioplasty (PTCA). This was a retrospective case-control study of 66 patients with moderate chronic renal failure who underwent PTCA, and who were matched to 66 PTCA patients with normal renal function and followed up by telephone interviews. In hospital, patients with renal failure suffered significantly more often from local complications (12.1 vs 0%, P = 0.004) and acute deterioration of renal function after PTCA (7.6 vs 0%, P = 0.023) than their matched controls. Angiographic success after PTCA was not significantly different (85 vs 83%, n.s.) as was the case with in-hospital mortality (6.1 vs 3.0%, n.s.). During follow up (100% complete), 18 patients (27.3%) with renal failure had died compared with seven controls (10.6%; OR 3.2, P = 0.015). Even if deaths from non-cardiac causes in three patients with renal failure were excluded, death after PTCA occurred significantly more often in the renal failure group (P = 0.015, log rang test). Multivariate analyses with stepwise logistic regression identified impaired left ventricular function (OR 2.24, 95%CI 1.33-3.77), elevated serum creatinine (OR 2.02, 95%CI 1.24-3.31) and smaller height (OR 0.91, 95%CI 0.86-0.98) to be independently associated with death. In conclusion, in this matched-pair study, patients with chronic renal failure suffered from more in-hospital complications and from markedly increased long-term mortality after PTCA.

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.

Early results of off-pump coronary artery bypass grafting for patients on chronic renal dialysis

OBJECTIVE

Renal dialysis is one of the independent risk factors for coronary artery bypass graft surgery. Off-pump coronary artery bypass grafting (OPCAB) may become a good option for these patients. In this study, early results as well as surgical techniques of OPCAB in dialysis patients were analyzed compared with non-dialysis patients.

METHODS

Between July 1997 and December 2002, 471 consecutive patients who underwent OPCAB were enrolled in this study. Among them, 20 patients (4.2%) had received hemodialysis regularly for more than 3 months until the operation. Severity of coronary artery disease or clinical presentations had no significant difference, however, left ventricular function was significantly impaired in dialysis patients.

RESULTS

The average number of anastomosis was 2.8 +/- 1.0 in the dialysis group and 3.2 +/- 1.0 in the non-dialysis group (p=0.056). Twelve patients (60.0%) received 3 or more bypass grafts in the dialysis group. Among them, 6 patients were revascularized only by in-situ or composite arterial conduits using bilateral internal thoracic arteries with or without the gastroepiploic artery. No patients required aortic clamping in the dialysis group. There was no mortality or morbidity in dialysis patients. Perioperaitve bleeding and mechanical ventilation time in the intensive care unit was similar in both groups. No dialysis patients required prolonged mechanical ventilation and hemodialysis from the beginning of the operation to extubation.

CONCLUSION

The rationale for OPCAB for dialysis patients has been established. Total arterial revascularization without aortic clamping is applicable for dialysis patients who require multivessel bypass grafts.

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.

The renal patient with coronary artery disease

The patient with chronic kidney disease and coronary artery disease (CAD) presents special challenges. This report reviews the scope of the challenge, the hostile internal milieu predisposing to CAD and cardiac events, management issues, unresolved dilemmas, and the need for randomized trials to allow for evidence-based treatment.

Impact of renal disease in cardiovascular surgery: emphasis on the African-American patient

Cardiovascular disease remains a significant source of morbidity and mortality for patients with kidney disease. Coincident with the development of chronic renal failure, patients typically manifest a systemic vasculopathy often involving the cardiovascular system. The renal failure patient is also plagued by multiple comorbid conditions that may adversely affect cardiovascular outcomes. Consistent with the national trend of increasing numbers of patients requiring renal replacement therapy (RRT), patients requiring invasive cardiovascular procedures are also on the incline. The morbidity and mortality related to these procedures has remained high despite significant advances in delivery and maintenance of care. Is the African-American patient with renal failure unique in terms of cardiovascular morbidity and mortality? Numerous studies have documented racial differences in access to invasive cardiovascular procedures, even after controlling for multiple physiologic risk factors and socioeconomic and sociocultural factors. Studies have also shown higher morbidity and lower survival for African-American patients after cardiac procedures. In this high-risk population these same issues perhaps would persist. The following paper will examine the current status of cardiovascular disease in the renal failure patient with emphasis on the African-American patient population.

Safety and efficacy of off-pump coronary artery bypass grafting in chronic dialysis patients

Off-pump coronary artery bypass grafting (CABG) has been recently revived, because cardiopulmonary bypass (CPB) appears to worsen the multiple organ dysfunction after conventional CABG. To evaluate the safety and efficacy of the off-pump CABG in chronic dialysis patients, we compared the perioperative morbidity and mortality between 15 dialysis patients who underwent off-pump CABG at our center over the past 8 years with that of a concurrent group of 19 patients who underwent conventional CABG. Patients were selected for off-pump CABG only when complete revascularization was technically feasible. We found that off-pump CABG is as safe and effective as conventional CABG in selected dialysis patients. It might even be beneficial, because it is associated with less hematocrit drop and blood product use, a lower catabolic rate, and fewer dialysis requirements after surgery. However, the impact of off-pump technique on the long-term clinical outcome and resource utilization in renal patients requires further investigation.

Does Myocardial Revascularization With Multiple Arterial Grafts Improve the Prognosis of Dialysis Patients?

In the present study it was examined whether myocardial revascularization with multiple arterial grafts improves the prognosis of dialysis patients. The 20 subjects underwent coronary artery bypass grafting over 2 vessels (extra-corporeal circulation in 11 patients, off-pump bypass in 9 patients) and were divided into 2 groups according the number of arterial grafts. Group A consisted of 9 patients in whom more than 2 arterial grafts were used and Group B, 11 patients requiring 1 internal thoracic artery and additional saphenous vein grafts. The surgical procedure was examined, as well as the short-term and long-term results of both groups. There were no differences in the profiles of the 2 groups. The mean arterial graft number in group A was 2.2+/-0.6 and 1.0+/-0.0 in group B. There was neither mediastinitis nor brain complication in either group. There were no operative deaths in group A and 1 in group B. The 55-month actuarial survival rate including all deaths, and estimated by cardiac deaths, was, respectively, 0.53+/-0.21 and 0.80+/-0.18 in group A and 0.42+/-0.21 and 0.53+/-0.23 in group B. The survival rate estimated by cardiac death in group A was better, but there was not a significant difference. Myocardial revascularization with multiple arterial grafts for dialysis patients had good short-term results without increased operative risk and may improve the long-term results related to cardiac death. However, there was no significant difference in survival including all deaths because of the numerous non-cardiac deaths.

[Coronary artery surgery in diabetic patients]

Currently, 15% to 30% of the patients that undergo coronary artery surgery are diabetics. As a group, they have less favorable anatomic and clinical characteristics than the general population. Specifically, diabetics have more extensive coronary disease, more vessels involved, and more diffuse stenosis, so they need a higher number of distal anastomoses to achieve complete revascularization. In spite of these drawbacks, they can undergo coronary artery bypass procedures with an operative mortality similar to that of non-diabetic patients. However, some postoperative complications are significantly more prevalent among diabetics, mainly renal failure, neurological accidents, sternal dehiscence, and infection. In early studies of the late results of surgical revascularization, mainly based on venous grafts, late survival and clinical improvement were less satisfactory in diabetics than in non-diabetics. However, in recent experiences, in which the internal mammary artery has been used extensively, the clinical outcome of diabetics has been similar to that of non-diabetics, confirming this procedure as the preferred one in revascularizing the coronary arteries of diabetics with multivessel disease. Off-pump surgery and extensive use of arterial grafts are becoming established strategies for reducing operative risk and improving long-term clinical results. However, continuous, strict medical management of hyperglycemia and other known coronary risk factors, especially lipid levels, is essential.

Coronary revascularization in the 21st century. Emphasis on contributions by Japanese surgeons

The first three decades of coronary artery surgery have provided the foundation for the next century of this evolution. It is apparent that a multitude of events including the development of cardioplegia, improving surgical instrumentation, technological advances including endoscopic approaches and computer assisted robotics and biologic discoveries such as the role of the endothelium have provided the underpinnings for improved surgical outcomes. However, the single most important determinant of late results is the type of bypass conduit used for grafting. Thus, use of the left internal thoracic artery (ITA) grafted to the left anterior descending coronary is a more important determinant of survival than is any other factor (progression of coronary artery disease, increased age, poor left ventricular function, diabetes, female gender and off-pump operations). Use of two ITAs provides further benefit and it is likely that three or more arterial conduits will be shown to be advantageous in this regard in due time. Japanese cardiothoracic surgeons have made significant contributions to the continuing evolution of coronary bypass surgery and particularly to the advance of arterial conduits. This report will address those contributions to this evolution.

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

Patients with both end-stage renal disease and diabetes mellitus carry an increased risk of coronary atherosclerosis. This study was performed to evaluate the perioperative and remote outcome of diabetic nephropathy patients on hemodialysis undergoing coronary artery bypass grafting (CABG). We retrospectively analyzed the results of CABG performed between September 1, 1993 and August 31, 2001. Preoperative, perioperative, and follow-up data of patients with hemodialysis primarily due to diabetic nephropathy (Group D, n = 31, 22 males and 9 females with a mean age of 60.1 +/- 6.6) were collected and compared to patients with hemodialysis primarily due to nondiabetic nephropathy (group N, n = 21, 17 males and 4 females with a mean age of 60.9 +/- 11.2). Preoperative risk factors between the 2 groups were not significantly different. The mean number of distal anastomoses was 2.5 +/- 1.2 in Group D and 2.5 +/- 1.0 in Group N (p = not significant [NS]). All patients received at least 1 internal mammary artery graft. There was 1 in-hospital death in each group. Postoperative recovery, mortality, and morbidity were not significantly different between the two groups. At the mean follow-up of 2.7 years, the actuarial 3 year survival rate was 72.8% in Group D and 78.7% in Group N (p = NS). The actuarial 3 year cardiac event-free rate was 79.7% in Group D and 74.7% in Group N (p = NS). CABG for hemodialysis patients can be performed with acceptable risks. Diabetic nephropathy has no impact on early or remote patient outcomes among patients on hemodialysis.

Cardiac surgery in moderate to end-stage renal failure: analysis of risk factors

BACKGROUND

The incremental surgical risk caused by different categories of renal failure is not well defined.

METHODS

Data from 159 patients with moderate to end-stage renal dysfunction, who had consecutive operations using cardiopulmonary bypass, were included in a multivariate analysis of morbidity and survival. Ninety-nine patients had preoperative serum creatinine levels (PSCL) of 1.9 to 2.5 mg/dL (moderate), 36 had PSCL higher than 2.5 mg/dL and were not dialysis dependent (severe), and 24 required chronic dialysis (end-stage dysfunction).

RESULTS

Operative mortality was 4% with moderate dysfunction and compared favorably with 16.7% in severe and 8% in end-stage dysfunction (p < 0.05). Independent predictors of death were severe non-dialysis-dependent renal dysfunction (p < 0.05), diabetes (p < 0.05), and cardiopulmonary bypass time (p < 0.01). Severe renal dysfunction (p < 0.01) and diabetes (p < 0.01) also predicted pulmonary and neurologic morbidity. Freedom from late death at 4 years was 82% +/- 5% with moderate, 49% +/- 10% with severe, and 60% +/- 10% with end-stage dysfunction (p < 0.01). Time to late death was adversely affected by severe (p < 0.05) and end-stage dysfunction (p < 0.01). Persistent improvement of symptoms was observed in all subgroups.

CONCLUSIONS

Satisfactory early and late surgical outcomes may be expected in patients with moderate renal failure, but outcomes are often poor with severe non-dialysis-dependent and end-stage renal dysfunction.

Long-term survival of dialysis patients after coronary bypass grafting

BACKGROUND

Dialysis patients are undergoing coronary artery bypass grafting (CABG) with increasing frequency. The long-term effect of preoperative dialysis-dependent renal failure on mortality after CABG has not been well studied.

METHODS

We conducted a prospective regional cohort study of 15,574 consecutive patients undergoing isolated CABG in northern New England from 1992 to 1997. Patient records were linked to the National Death Index to assess mortality. Five-year survival and adjusted hazard ratios were calculated.

RESULTS

During 32,589 person-years of follow-up 1298 deaths were recorded. Renal failure was present in 283 patients (1.8%), and 67.8% of patients with renal failure also had diabetes or peripheral vascular disease (PVD). The annual death rate was 3.8% for nonrenal failure patients, 16.9% for all renal failure patients, 7.7% for renal failure patients without diabetes or PVD, and 23.0% for renal failure patients with diabetes or PVD. Five-year survival was 83.5% for nonrenal failure patients, 55.8% for all renal failure patients, 78.5% for renal failure patients without diabetes or PVD, and 42.2% for renal failure patients with diabetes or PVD. After adjustment for differences in base line patient and disease characteristics, renal failure patients without diabetes or PVD had a statistically nonsignificant 57% increase rate of death compared with those without renal failure; renal failure patients with diabetes or PVD had more than a fourfold increased risk of death.

CONCLUSIONS

After adjustment for other risk factors, renal failure remains a highly significant predictor of decreased long-term survival in CABG patients. Patients with renal failure plus diabetes or PVD are at especially high risk of death.

Early and long-term results of coronary artery bypass grafting in dialysis patients

OBJECTIVE

We evaluated the surgical outcome of coronary artery bypass grafting in dialysis patients.

METHODS

We retrospectively analyzed 25 consecutive dialysis patients requiring isolated coronary artery bypass grafting. Their mean age was 61.6 years and average dialysis duration 80.4 months.

RESULTS

Eight patients (32%) had emergency or urgent surgery. The mean number of bypassed vessels was 3.3 +/- 1.2. Internal thoracic artery grafts were used in 19 patients and gastroepiploic artery grafts in 5. Two (8%) died during hospitalization and complications occurred in 11 (44%). No cerebral complications were observed. All survivors showed ameliorated symptoms and improved overall function. Of 14 late deaths, 5 were cardiac-related, with 2 involving obvious myocardial ischemic events. Actuarial survival, including hospital deaths, at 1 year was 70.9%, at 3 years was 43.5%, and at 5 years was 34.8%. Cardiac-death-free survival was 70.2% at 3 years and 70.2% at 5 years.

CONCLUSION

Coronary artery bypass grafting in dialysis patients is associated with a higher incidence of complications but has acceptable surgical mortality and effectively relieves angina symptoms.

Myocardial Revascularization in Chronic Renal Failure: 10-Year Experience

From January 1989 to June 1999, 244 patients with chronic renal failure underwent myocardial revascularization, of whom 56 were undergoing hemodialysis (group 1) and 188 (group 2) did not require hemodialysis. Mean age was 63.4 ± 6.5 years in group 1 and 65.4 ± 7 years in group 2. Hospital mortality was 7% overall; 6 (10.7%) patients died in group 1 versus 11 (5.9%) in group 2 (p > 0.05). Post-operative complications were significantly higher in group 1 versus group 2. Multivariate analysis revealed cerebrovascular disease, myocardial infarction, left ventricular ejection fraction < 35%, and duration of renal failure as strong predictors of poor survival in non-dialysis patients. Left ventricular ejection fraction < 35% and duration of hemodialysis were predictors of late mortality in group 1. The 1-, 3-, and 5-year survival rates were 90%, 76%, and 68% in group 1, and 95.5%, 86%, and 80.7% in group 2 (p < 0.004), respectively. Myocardial revascularization can be carried out in patients with chronic renal failure with acceptable early and late mortality and morbidity, but those undergoing hemodialysis are at substantial risk of major morbid events and poor long-term survival.