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

Total arch replacement in patients with chronic kidney disease

BACKGROUND

We investigated the effect of preoperative renal dysfunction on postoperative outcomes in patients undergoing elective isolated total arch replacement (TAR) with mild hypothermic lower body circulatory arrest with antegrade selective cerebral perfusion (SCP).

METHODS

One hundred and forty-four patients who had undergone elective isolated TAR between January 2002 and December 2019 were retrospectively analyzed. Patients were divided into two groups according to whether their preoperative estimated glomerular filtration rate (eGFR) was lower than or higher than 60 ml/min/1.73 m² . We compared perioperative data and mid-term outcomes after adjusting for patients' baseline characteristics using weighted logistic regression analysis and inverse probability of treatment weighting.

RESULTS

More patients underwent postoperative stroke in the chronic kidney disease group compared with the normal group (2.8% vs. 0%, respectively; p = .049). Overall 30-day mortality and hospital mortality were 0% in both groups, and there was no significant difference in overall survival between the two groups (log-rank test, p = .129). Multivariate Cox proportional hazard analysis showed that eGFR < 60 ml/min/1.73 m² was not an independent predictor (hazard ratio: 1.636, 95% confidence interval 0.829-3.231; p = .156).

CONCLUSIONS

Preoperative eGFR <60 ml/min/1.73 m² was not associated with worse outcomes after elective isolated TAR with mild hypothermic lower body circulatory arrest with antegrade SCP.

Cerebrovascular CO2 reactivity during isoflurane-nitrous oxide anesthesia in patients with chronic renal failure

PURPOSE

We assessed the cerebrovascular CO₂ reactivity (CO₂R) in chronic renal failure (CRF) patients without diabetes mellitus (DM), uncontrolled hypertension, peripheral vascular disease, or neurological disease under isoflurane-nitrous oxide anesthesia.

METHODS

Forty-nine patients undergoing surgery, including 36 CRF patients (30 receiving dialysis and six pre-dialysis patients) and 13 patients without CRF (controls). Middle cerebral artery flow velocity (VMCA) was measured by transcranial Doppler ultrasonography at an end-tidal CO₂ of 35 to 45 mmHg. CO₂R was calculated as an absolute value (change in VMCA per mmHg PaCO₂) and a relative value (absolute CO₂R/baseline VMCA × 100). Factors associated with CO₂R were evaluated simultaneously.

RESULTS

Despite no significant differences in the absolute and relative values of CO₂R between the CRF (mean 2.5 cm/s/mmHg; median 5.0%/mmHg) and control (2.4 cm/s/mmHg; 5.0%/mmHg) groups, blood urea nitrogen (BUN) concentrations in the CRF group correlated inversely with both absolute and relative CO₂R. BUN concentration was higher (mean 72 versus 53 mg/dl, p = 0.006) and relative CO₂R was lower (mean 2.6 versus 5.7%/mmHg, p = 0.011) in patients with pre-dialysis CRF (n = 6) versus CRF patients receiving dialysis (n = 30).

CONCLUSIONS

CO₂R in CRF patients was not significantly different from that in controls. However, in CRF patients with high BUN concentrations, CO₂R might be impaired, leading to reduced cerebrovascular reserve capacity. Because DM is a major cause of CRF and we excluded DM patients, our results might not be applicable to patients with DM-induced CRF.

Effect of Prophylactic Dialysis on Morbidity and Mortality in Non-Dialysis-Dependent Patients after Coronary Artery Bypass Grafting: A Pilot Study

BACKGROUND/AIMS

Coronary artery bypass grafting (CABG) is associated with an increased risk of morbidity and mortality in patients with pre-existing renal dysfunction. Numerous measures have been implemented to overcome this problem; however, no improvement in outcomes has been achieved. This study was aimed at investigating the effects of prophylactic dialysis on mortality and morbidity in these patients.

METHODS

This randomized-controlled clinical trial enrolled 88 non-dialysis-dependent patients with chronic kidney disease awaiting CABG surgery. Thirty-nine randomly selected patients received dialysis 3 times prior to surgery, and 49 patients formed the control group. Kaplan-Meier analysis and Cox proportional-hazards models were used to identify factors associated with survival.

RESULTS

There was no significant difference in the development of morbidities between the groups (p = 0.413). A significant difference was evident in the average survival time (p = 0.037). Cox proportional-hazards models determined that the hazard ratio of death after surgery was 10.854-fold greater in non-dialysis patients than in patients who received dialysis (hazard ratio = 2).

CONCLUSION

Prophylactic dialysis prior to CABG decreases mortality, but does not affect morbidity, in patients with renal insufficiency.

Bioprosthetic versus mechanical prostheses for valve replacement in end-stage renal disease patients: systematic review and meta-analysis

BACKGROUND

Patients with end-stage renal disease (ESRD) indicated for dialysis are increasingly requiring cardiac valve surgery. The choice of bioprosthetic or mechanic valve prosthesis for such patients requires careful risk assessment. A systematic review and meta-analysis was performed to assess current evidence available.

METHODS

A comprehensive search from six electronic databases was performed from their inception to February 2015. Results from patients with ESRD undergoing cardiac surgery for bioprosthetic or mechanical valve replacement were identified.

RESULTS

Sixteen studies with 8,483 patients with ESRD undergoing cardiac valve replacement surgery were included. No evidence of publication bias was detected. Prior angioplasty by percutaneous coronary intervention (PCI) or coronary artery bypass graft (CABG) surgery was significantly higher in the bioprosthetic group compared to the mechanical group (16.0% vs. 12.0%, P=0.04); all other preoperative baseline patient characteristics were similar. There was no significant difference in 30-day mortality or all-cause mortality between the two comparisons. Compared with the mechanical group, the frequency of bleeding (5.2% vs. 6.4%, P=0.04) and risk of thromboembolism (2.7% vs. 12.8%, P=0.02) were significantly lower in the bioprosthetic group. There were similar rates of reoperation and valve endocarditis.

CONCLUSIONS

The present study demonstrated that patients with ESRD undergoing bioprosthetic or mechanical valve replacement had similar mid-long term survival. The bioprosthetic group had lower rates of bleeding and thromboembolism. Further studies are required to differentiate the impact of valve location. The presented results may be applicable for ESRD patients requiring prosthetic valve replacement.

Difficulty of patient selection in a combined heart-kidney transplant: a case report

Combined heart-kidney transplant has become an alternative for heart transplant candidates with significant chronic kidney disease. However, it is not clear which patients will benefit most from such intervention, and in whom cardiac transplant alone will be sufficient to restore adequate renal function. We report the case of a man with ischemic cardiomyopathy and chronic kidney disease who was wait-listed for heart-kidney transplant after acute decompensated heart failure and renal failure requiring hemodialysis. Because of unexpected circumstances, the kidney transplant was cancelled, and only a heart transplant was performed. Nonetheless, the kidney function rapidly improved beyond the levels before hospitalization and remains stable months after transplant. This case illustrates the difficulties in assessing the reversibility of kidney damage in the context of heart failure requiring transplant. This issue is primordial to improve selection of patients who will benefit most from combined heart-kidney transplant in a context of scarce organ allocation resources.

Are non-cardiac surgeries safe for dialysis patients? - A population-based retrospective cohort study

BACKGROUND

End-stage renal disease represents a risk complex that complicates surgical results. The surgical outcomes of dialysis patients have been studied in specific fields, but the global features of postoperative adverse outcomes in dialysis patients receiving non-cardiac surgeries have not been examined.

METHODS

Taiwan's National Health Insurance Research Database was used to study 8,937 patients under regular dialysis with 8,937 propensity-score matched-pair controls receiving non-cardiac surgery between 2004 and 2007. We investigated the influence of hemodialysis and peritoneal dialysis, effects of hypertension and diabetes, and impact of additional comorbidities on postoperative adverse outcomes.

RESULTS

Postoperative mortality in dialysis patients was higher than in controls (odds ratio [OR] 3.33, 95% confidence interval [CI] 2.56 to 4.33) when receiving non-cardiac surgeries. Complications such as acute myocardial infarction, pneumonia, bleeding, and septicemia were significantly increased. Postoperative mortality was significantly increased among peritoneal dialysis patients (OR 2.71, 95% CI 1.70 to 4.31) and hemodialysis patients (OR 3.42, 95% CI 2.62 to 4.47) than in controls. Dialysis patients with both hypertension and diabetes had the highest risk of postoperative complications; these risks increased with number of preoperative medical conditions. Patients under dialysis also showed significantly increased length of hospitalization, more ICU stays and higher medical expenditures.

CONCLUSION

Surgical patients under dialysis encountered significantly higher postoperative complications and mortality than controls when receiving non-cardiac surgeries. Different dialysis techniques, pre-existing hypertension/diabetes, and various comorbidities had complication-specific impacts on surgical adverse outcomes. These findings can help surgical teams provide better risk assessment and postoperative care for dialysis patients.

Influence of minimal changes in preoperative renal function on outcomes of cardiac surgery

BACKGROUND/AIMS

Cardiovascular morbidity and mortality are high in patients with chronic kidney disease. We evaluated the influence of small differences in preoperative kidney function on mortality and complications following cardiac surgery.

METHODS

This is an observational study that included adult patients undergoing cardiac surgery. Preoperative estimated glomerular filtration rate (eGFR) was estimated by the 4-component Modification of Diet in Renal Disease (MDRD) and Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) equations based on preoperative creatinine levels. For analysis, patients were divided into groups according to their preoperative creatinine (0.2 mg/dl increments) and eGFR levels (15-30 ml/min/1.73 m(2) decrements).

RESULTS

Data on 5,340 patients were analyzed. A significant increase in postoperative mortality was demonstrated with preoperative creatinine at high-normal versus low-normal values (OR 1.7, 95% CI: 1-2.5; p = 0.02). For preoperative creatinine >1.2 mg/dl, adjusted OR for in-hospital mortality increased stepwise with every 0.2-mg/dl increment of creatinine. In addition, a statistically significant increment of mortality was detected with every 15-ml/min/1.73 m(2) decrement in preoperative eGFR.

CONCLUSIONS

Minimal changes of preoperative kidney function are associated with a substantial increase in the risk of mortality and morbidity following cardiac surgery. Even within the 'normal' range, minimal increases in serum creatinine levels are associated with increased risk of adverse events postoperatively.

Impact of preoperative renal dysfunction on outcomes of off-pump coronary artery bypass grafting

BACKGROUND

This study assessed whether preoperative renal insufficiency predisposes patients undergoing off-pump coronary artery revascularization to postoperative dialysis.

METHODS

From August 2004 through June 2009, 2,275 patients undergoing off-pump coronary artery bypass were categorized into five groups (stages) by glomerular filtration rate (GFR). Of these, 1,855 patients had renal insufficiency: stage 2: 1,406; stage 3: 428; stage 4: 21, and 414 had normal renal function, stage 1. Excluded were 6 patients with end-stage renal disease (stage 5). Preoperative variables and postoperative outcomes were compared among groups.

RESULTS

Preoperative patient characteristics were similar; however, patients with normal renal function were younger (p = 0.001). Serum creatinine rose significantly above baseline on the first postoperative day in the renal insufficiency groups (p = 0.001). The GFR groups had similar inotrope use, reexploration rate, duration of postoperative mechanical ventilation, postoperative stroke, wound infection, and mortality rate. Stage 4 patients had a higher incidence of postoperative myocardial infarction (p = 0.002). Stage 3 and 4 patients had an increased need for postoperative dialysis vs stage 1 patients (p = 0.002).

CONCLUSIONS

Nonparametric contingency analysis showed patients with low preoperative GFR (stage 3 and 4, p < 0.0001) and a history of smoking (p = 0.04) were at increased risk for postoperative dialysis. Patients who required postoperative inotropic support tended toward requiring postoperative dialysis (p = 0.06). Low preoperative ejection fraction (p = 0.83), class III or IV angina (p = 0.069), and postoperative blood transfusions were not associated with the need for postoperative dialysis in patients undergoing off-pump revascularization.

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.

Cystatin C blood level as a risk factor for death after heart surgery

AIMS

Pre-operative renal dysfunction is a known risk factor for mortality and morbidity after heart surgery. Despite limited accuracy, serum creatinine is widely used to estimate glomerular filtration rate (GFR). Cystatin C is more accurate for assessing GFR. The aim of the present study was to assess associations between GFR estimated from serum cystatin C levels before heart surgery and hospital mortality, hospital morbidity, and 1 year mortality.

METHODS AND RESULTS

In a prospective single-centre observational study, clinical risk factors for morbidity and mortality were recorded and serum creatinine and cystatin C levels were measured in patients admitted for heart surgery. Hospital mortality and morbidity and 1 year mortality were recorded. Over an 8 month period, 499 patients were screened, among whom 376 (74.5%) were included in the study. Hospital mortality was 5.6% (21 patients) and 1 year mortality was 10.2%. Hospital morbidity, defined by a length of stay above the 75th percentile, was 22.1% (83 patients). In the multivariable analysis, GFR estimated from serum cystatin C, but not GFR estimated from serum creatinine, was an independent risk factor for hospital morbidity/mortality (odds ratio per 10 mL/min of GFR decrease, 1.20 (1.07-1.34), P = 0.001) and for 1 year mortality (hazards ratio per 10 mL/min of GFR decrease, 1.26 (1.09-1.46), P = 0.002).

CONCLUSION

Pre-operative GFR estimation from serum cystatin C may provide a better risk assessment than pre-operative GFR estimation from serum creatinine in patients scheduled for heart surgery.

Valve replacement surgery in end-stage renal failure: mechanical prostheses versus bioprostheses

BACKGROUND

The 1998 American College of Cardiology/American Heart Association Guidelines recommend mechanical prostheses for valve replacement in patients with end-stage renal disease requiring dialysis. The aim of the study is to evaluate the combined experience at two academic centers.

METHODS

Sixty-nine valve replacements (aortic 40; mitral 22; multiple 7; 47 bioprostheses, 22 mechanical prostheses) were performed. Total follow-up was 128.7 patient-years (bioprostheses, 68.4; mechanical prostheses, 60.4).

RESULTS

Patient populations were homogeneous, except for age (bioprostheses greater than mechanical prostheses, p = 0.012), previous myocardial infarction (bioprostheses greater than mechanical prostheses, p = 0.040), and concomitant CABG (bioprostheses greater than mechanical prostheses, p = 0.019). A survival advantage was observed in favor of mechanical prostheses (p = 0.0299) at 5 years. Freedom from valve-related complications at 5 years was calculated for thromboembolism plus thrombosis plus hemorrhage (bioprostheses, 93.0% +/- 3.9%; mechanical prostheses, 76.4% +/- 12.7%), thromboembolism excluding thrombosis (bioprostheses, 93.0% +/- 3.9%; mechanical prostheses, 88.9% +/- 10.5%), and hemorrhage (bioprostheses, 100%; mechanical prostheses, 95.2% +/- 4.7%). One case of structural valve deterioration occurred in the bioprostheses group at 95 months after surgery. Five-year freedom from all valve-related complications was 82.8% +/- 8.1% for bioprostheses and 76.4% +/- 12.7% for mechanical prostheses.

CONCLUSIONS

Overall survival was poor. Differences between populations were related to age at operation and coronary artery disease. Structural valve deterioration was not accentuated with bioprostheses. Considering lack of homogeneity between prostheses groups there was no superiority of mechanical prostheses over bioprostheses in terms of freedom from composites of complications. Bioprostheses should be considered in the management of valvular disease in end-state renal disease patients.

Early continuous venovenous hemodialysis in dialysis-dependent patients after cardiac surgery: safety and efficacy

OBJECTIVES

The present study assessed the safety and efficacy of continuous venovenous hemodialysis (CVVHD) early after cardiac surgery.

DESIGN

Retrospective database and medical record review.

SETTING

University teaching hospital.

PARTICIPANTS

Forty-five dialysis-dependent patients who underwent cardiac surgery with cardiopulmonary bypass.

INTERVENTIONS

CVVHD was begun postoperatively after confirmation of hemostasis, irrespective of circulatory status. In the last 5 patients, the ratio of extravascular lung water (EVLW) to intrathoracic blood volume (ITBV) was measured using a single-indicator thermodilution catheter and compared with patients of normal renal function undergoing cardiac surgery.

MEASUREMENTS AND MAIN RESULTS

CVVHD was started at 4 hours after ICU admission. The maximum decrease in blood pressure within 60 minutes after initiation of CVVHD was 11 +/- 9 mmHg in the unstable hemodynamics group (defined as patients who required continuous intravenous adrenaline or intra-aortic balloon pump on admission to the ICU [n = 15]) and 7 +/- 8 mmHg in the stable hemodynamics group (n = 30, not significant). Circulatory status and oxygenation improved significantly 12 hours after CVVHD initiation in the unstable hemodynamics group. Blood volume from the chest tube did not increase after CVVHD. Early mortality (2.2%) was lower than that reported previously. The EVLW/ITBV ratio after ICU admission in dialysis-dependent patients was significantly higher than in patients with normal renal function.

CONCLUSIONS

Early CVVHD after cardiac surgery in dialysis-dependent patients was safe and effective. There was no associated increased postoperative bleeding or hemodynamic instability. Fluid removal improved respiratory status, particularly in patients requiring circulatory assistance, and overall early morality rates were lower that those previously published.

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.

Peri-operative Renal Function and Outcome after Orthotopic Heart Transplantation

BACKGROUND

Renal insufficiency is an established risk factor in patients undergoing cardiovascular surgery. We sought to evaluate the relationship between renal function and outcomes after orthotopic heart transplantation (OHT).

METHODS

We conducted a retrospective review of 622 adults who underwent 628 consecutive OHTs between 1994 and 2001 at our institution. The recipients were divided into either normal (Group 1) or impaired (Group 2) pre-operative renal function. Impaired renal function was defined as creatinine clearance (CrCl) < 40 ml/min (Cockroft-Gault formula). Meanwhile, patients in Group 1 (normal) were defined by CrCl > or = 40 ml/min. The primary end points of the study were early and late mortality. The secondary end point included post-operative renal failure defined by the requirement of dialysis or renal allograft in the early post-operative period. The Kaplan-Meier method was used to determine actuarial survival.

RESULTS

Early mortality was 7% (38/531) in Group 1 and 17% (16/96) in Group 2 (p = 0.002). Similarly, the death rate per 100 patient-years was 4.8 and 8.1 for the groups, respectively (p = 0.03). Nine percent of patients in Group 1 required post-operative dialysis (49/531), whereas 32% of recipients in Group 2 required this intervention (31/96) (p < 0.001). Early mortality was 41% for patients requiring post-operative dialysis and 3% for those not requiring such intervention (p < 0.001). Early mortality after post-operative dialysis was 41% (20/49) in Group 1 and 42% (13/31) in Group 2 (p = 0.2).

CONCLUSIONS

CrCl < 40 ml/min is a useful marker for increased post-operative renal failure and mortality. Recipients who require post-operative dialysis have greatly increased mortality regardless of pre-operative CrCl. Dialysis in patients after heart transplantation carries a prohibitive risk. Dialysis as a bridge to renal transplantation may reduce this high mortality rate.

The Outcome of Cardiac Surgery in Dialysis-Dependent Patients

BACKGROUND

Patients on dialysis for end-stage renal failure (ESRF) are undergoing cardiac surgery with increasing frequency. Furthermore, ESRF is known to be an important risk factor for complications of cardiac operations performed with cardiopulmonary bypass.

AIMS

To evaluate the outcome of dialysis-dependent patients undergoing cardiac surgery at one institution.

METHODS

A retrospective analysis was performed on consecutive patients with ESRF dependent upon maintenance haemodialysis or peritoneal dialysis who underwent cardiac surgery from January 1998 to August 2002.

RESULTS

Thirty-eight patients on dialysis underwent cardiac surgery during this time period (1.5% of total cases). The most common cause for ESRF was diabetic nephropathy (n = 12). Operations performed included isolated coronary artery bypass grafting (CABG, n = 22), CABG and valve surgery (n = 8), and valve surgery alone (n = 6). When allowing for age, sex, surgeon and operative category, the odds ratio for mortality risk of dialysis patients, compared with all others, was 4.9 (95% confidence interval (CI): 1.7-13.9, p = 0.003), and for morbidity risk, was 2.8 (95% CI: 1.4-5.4, p = 0.003).

CONCLUSIONS

Patients on dialysis have an increased morbidity and mortality following cardiac surgery, however we believe ESRF should not be regarded as an absolute contraindication to cardiac surgery or cardiopulmonary bypass.

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.

Is off-pump revascularization better for patients with non-dialysis-dependent renal insufficiency?

BACKGROUND

Renal dysfunction is a well-recognized complication following coronary artery bypass grafting (CABG). Coronary revascularization without cardiopulmonary bypass (CPB) has been shown to minimize renal injury in patients with normal preoperative renal function who undergo elective procedures. The purpose of this study was to define the effect of an off-pump revascularization strategy on the incidence of postoperative renal failure and survival of patients with preexisting renal dysfunction.

METHODS

From January 1, 1999, to December 1, 2002, a total of 371 patients were identified as having a preoperative creatinine concentration greater than or equal to 1.5 mg/dL. This number included 291 patients who did not need hemodialysis or peritoneal dialysis to support renal function. These patients were subdivided into those undergoing traditional CABG with CPB (103 patients) and those undergoing off-pump revascularization (188 patients) whose demographic, operative, and outcome information was retrospectively reviewed and compared.

RESULTS

The off-pump cohort was older than the on-pump cohort (70 +/- 9.6 versus 66 +/- 10.9 years; P =.002), had a lower prevalence of previous myocardial infarction (35% versus 50%; P =.008), and had a modestly higher mean left ventricular ejection fraction (0.47 +/- 0.01 versus 0.43 +/- 0.01; P =.017). Otherwise the groups were well matched. The mean preoperative serum creatinine and creatinine clearance values were not significantly different (1.8 +/- 0.5 versus 1.9 +/- 0.6 mg/dL [ P =.372] and 45.1 +/- 15.5 versus 46.8 +/- 17.2 mL/min [ P =.376] for the off-pump and on-pump cohorts, respectively). There was a significant reduction in postoperative renal failure (17% versus 9% of patients; P =.020) and need for new dialysis (10% versus 3% of patients; P =.022) when CPB was eliminated. Intermediate-term survival analysis revealed a survival benefit for the off-pump group (70% versus 57%) at 42 months, although this value did not reach statistical significance ( P =.143).

CONCLUSION

The results of this study suggested that patients with preoperative non-dialysis-dependent renal insufficiency have more favorable outcome when revascularization is done off pump. Avoidance of CPB results in (1) a reduction in the incidence of postoperative renal failure; (2) a reduction in the need for new dialysis; and (3) improved in-hospital and midterm survival.