Coronary artery bypass grafting in non-dialysis-dependent mild-to-moderate renal dysfunction

Prediction of Successful Liberation from Continuous Renal Replacement Therapy Using a Novel Biomarker in Patients with Acute Kidney Injury after Cardiac Surgery-An Observational Trial

An acute kidney injury (AKI) is the most common complication following cardiac surgery, and can lead to the initiation of continuous renal replacement therapy (CRRT). However, there is still insufficient evidence for when patients should be liberated from CRRT. Proenkephalin A 119-159 (PENK) is a novel biomarker that reflects kidney function independently of other factors. This study investigated whether PENK could guide successful liberation from CRRT. Therefore, we performed a prospective, observational, single-center study at the Medical University of Vienna between July 2022 and May 2023, which included adult patients who underwent cardiac surgery for a cardiopulmonary bypass; patients on preoperative RRT were excluded. The PENK levels were measured at the time of AKI diagnosis and at the initiation of and liberation from CRRT, and were subsequently compared to determine whether the patients were successfully liberated from CRRT. We screened 61 patients with postoperative AKI; 20 patients experienced a progression of AKI requiring CRRT. The patients who were successfully liberated from CRRT had mean PENK levels of 113 ± 95.4 pmol/L, while the patients who were unsuccessfully liberated from CRRT had mean PENK levels of 290 ± 175 pmol/L (p = 0.018). For the prediction of the successful liberation from CRRT, we found an area under the curve of 0.798 (95% CI, 0.599-0.997) with an optimal threshold value of 126.7 pmol/L for PENK (Youden Index = 0.53, 95% CI, 0.10-0.76) at the time of CRRT liberation (sensitivity = 0.64, specificity = 0.89). In conclusion, PENK is a novel biomarker that has the potential to predict the successful liberation from CRRT for patients with AKI after cardiac surgery.

Data-driven coaching to improve statewide outcomes in CABG: before and after interventional study

BACKGROUND

The impact of quality improvement initiatives program (QIP) on coronary artery bypass grafting surgery (CABG) remains scarce, despite improved outcomes in other surgical areas. This study aims to evaluate the impact of a package of QIP on mortality rates among patients undergoing CABG.

MATERIALS AND METHODS

This prospective cohort study utilized data from the multicenter database Registro Paulista de Cirurgia Cardiovascular II (REPLICCAR II), spanning from July 2017 to June 2019. Data from 4018 isolated CABG adult patients were collected and analyzed in three phases: before-implementation, implementation, and after-implementation of the intervention (which comprised QIP training for the hospital team). Propensity Score Matching was used to balance the groups of 2170 patients each for a comparative analysis of the following outcomes: reoperation, deep sternal wound infection/mediastinitis ≤30 days, cerebrovascular accident, acute kidney injury, ventilation time >24 h, length of stay <6 days, length of stay >14 days, morbidity and mortality, and operative mortality. A multiple regression model was constructed to predict mortality outcomes.

RESULTS

Following implementation, there was a significant reduction of operative mortality (61.7%, P =0.046), as well as deep sternal wound infection/mediastinitis ( P <0.001), sepsis ( P =0.002), ventilation time in hours ( P <0.001), prolonged ventilation time ( P =0.009), postoperative peak blood glucose ( P <0.001), total length of hospital stay ( P <0.001). Additionally, there was a greater use of arterial grafts, including internal thoracic ( P <0.001) and radial ( P =0.038), along with a higher rate of skeletonized dissection of the internal thoracic artery.

CONCLUSIONS

QIP was associated with a 61.7% reduction in operative mortality following CABG. Although not all complications exhibited a decline, the reduction in mortality suggests a possible decrease in failure to rescue during the after-implementation period.

Preoperative renal insufficiency predicts postoperative adverse outcomes in a mixed surgical population: a retrospective matched cohort study using the NSQIP database

BACKGROUND

The incidence of chronic kidney disease is increasing, but most cases are not diagnosed until the accidental finding of abnormal laboratory data or the presentation of severe symptoms. Patients with chronic kidney disease are reported to have an increased risk of postoperative mortality and morbidities, but previous studies mainly targeted populations undergoing cardiovascular surgery. The authors aimed to evaluate the risk of postoperative mortality and complications in a surgical population with preoperative renal insufficiency (RI).

MATERIALS AND METHODS

This retrospective cohort study used data from the National Surgical Quality Improvement Program database between 2013 and 2018 to evaluate the risk of postoperative morbidity and mortality in the surgical population. Patients with estimated glomerular filtration rate less than 60 ml/min/1.73 m 2 were defined as the RI group. Propensity score matching methods and multivariate logistic regression were used to calculate the risk of postoperative morbidity and mortality.

RESULTS

After propensity score matching, 502 281 patients were included in the RI and non-RI groups. The RI group had a higher risk of 30-day in-hospital mortality (odds ratio: 1.54, 95% CI: 1.49-1.58) than the non-RI group. The RI group was associated with a higher risk of postoperative complications, including myocardial infarction, stroke, pneumonia, septic shock, and postoperative bleeding. The RI group was also associated with an increased risk of prolonged ventilator use for over 48 h, readmission, and reoperation.

CONCLUSION

Patients with preoperative RI have an increased risk of postoperative 30-day mortality and complications. RI group patients with current dialysis, estimated glomerular filtration rate less than or equal to 30 ml/min/1.73 m 2 or concomitant anemia had an elevated risk of postoperative mortality.

Factors affecting mortality after coronary bypass surgery: a scoping review

Objectives

Previous research reports numerous factors of post-operative mortality in patients undergoing isolated coronary artery bypass graft surgery. However, this evidence has not been mapped to the conceptual framework of care improvement. Without such mapping, interventions designed to improve care quality remain unfounded.

Methods

We identified reported factors of in-hospital mortality post isolated coronary artery bypass graft surgery in adults over the age of 19, published in English between January 1, 2000 and December 31, 2019, indexed in PubMed, CINAHL, and EMBASE. We grouped factors and their underlying mechanism for association with in-hospital mortality according to the augmented Donabedian framework for quality of care.

Results

We selected 52 factors reported in 83 articles and mapped them by case-mix, structure, process, and intermediary outcomes. The most reported factors were related to case-mix (characteristics of patients, their disease, and their preoperative health status) (37 articles, 27 factors). Factors related to care processes (27 articles, 12 factors) and structures (11 articles, 6 factors) were reported less frequently; most proposed mechanisms for their mortality effects.

Conclusions

Few papers reported on factors of in-hospital mortality related to structures and processes of care, where intervention for care quality improvement is possible. Therefore, there is limited evidence to support quality improvement efforts that will reduce variation in mortality after coronary artery bypass graft surgery.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13019-022-01784-z.

Development and Validation of a Novel Nomogram for Preoperative Prediction of In-Hospital Mortality After Coronary Artery Bypass Grafting Surgery in Heart Failure With Reduced Ejection Fraction

Background and Aims: Patients with heart failure with reduced ejection fraction (HFrEF) are among the most challenging patients undergoing coronary artery bypass grafting surgery (CABG). Several surgical risk scores are commonly used to predict the risk in patients undergoing CABG. However, these risk scores do not specifically target HFrEF patients. We aim to develop and validate a new nomogram score to predict the risk of in-hospital mortality among HFrEF patients after CABG.

Methods: The study retrospectively enrolled 489 patients who had HFrEF and underwent CABG. The outcome was postoperative in-hospital death. About 70% (n = 342) of the patients were randomly constituted a training cohort and the rest (n = 147) made a validation cohort. A multivariable logistic regression model was derived from the training cohort and presented as a nomogram to predict postoperative mortality in patients with HFrEF. The model performance was assessed in terms of discrimination and calibration. Besides, we compared the model with EuroSCORE-2 in terms of discrimination and calibration.

Results: Postoperative death occurred in 26 (7.6%) out of 342 patients in the training cohort, and in 10 (6.8%) out of 147 patients in the validation cohort. Eight preoperative factors were associated with postoperative death, including age, critical state, recent myocardial infarction, stroke, left ventricular ejection fraction (LVEF) ≤35%, LV dilatation, increased serum creatinine, and combined surgery. The nomogram achieved good discrimination with C-indexes of 0.889 (95%CI, 0.839–0.938) and 0.899 (95%CI, 0.835–0.963) in predicting the risk of mortality after CABG in the training and validation cohorts, respectively, and showed well-fitted calibration curves in the patients whose predicted mortality probabilities were below 40%. Compared with EuroSCORE-2, the nomogram had significantly higher C-indexes in the training cohort (0.889 vs. 0.762, p = 0.005) as well as the validation cohort (0.899 vs. 0.816, p = 0.039). Besides, the nomogram had better calibration and reclassification than EuroSCORE-2 both in the training and validation cohort. The EuroSCORE-2 underestimated postoperative mortality risk, especially in high-risk patients.

Conclusions: The nomogram provides an optimal preoperative estimation of mortality risk after CABG in patients with HFrEF and has the potential to facilitate identifying HFrEF patients at high risk of in-hospital mortality.

Outcomes of off-pump coronary artery bypass grafting in non-dialysis-dependent patients with stage 2 and stage 3 chronic kidney disease

Purpose

To assess the short-term outcomes in non-dialysis-dependent patients with stage 2 and stage 3 chronic kidney disease (CKD), undergoing off-pump coronary artery bypass (OPCAB). To examine whether there was a difference in mortality between stage 2 and stage 3 CKD patients and whether mortality in diabetics was different compared to non-diabetics. Outcomes would be judged on the basis of possible cardiovascular, pulmonary, infective, neurological and renal complications, duration of stay at the intensive therapy unit (ITU), and overall duration of stay at the hospital. A comparative study of outcomes between stage 2 and stage 3 CKD would be undertaken. Also, given the impact of diabetes mellitus in this patient population, a comparative study of outcomes would be made between diabetics and non-diabetics.

Methods

Three hundred fifteen consecutive patients undergoing OPCAB were included in this observational prospective study. Of them, 201 (64%) had stage 3 CKD and 114 (36%) had stage 2 CKD. Nearly half of the study group (49.52%) were diabetics. Data was collected from patients' files, patient observation charts at the ITU, and patient interviews. Continuous variables were expressed as mean ± standard deviation or median (Q1, Q3) as appropriate and qualitative variables presented with the frequency and corresponding percentage. Comparison between diabetic and non-diabetic patients was performed by the Student's t test or chi-square test as appropriate. And when assumptions of parametric test failed, then an appropriate non-parametric test was performed. Repeated measures ANOVA (analysis of variance) was used to see the trend of estimated glomerular filtration rate (eGFR) values. Statistical analysis was done by using SPSS version 19.0 (SPSS Inc., Chicago, IL, USA). All p values <0.05 were considered statistically significant.

Results

The eGFR was measured pre-operatively, on the day following OPCAB and at the time of discharge and the mean eGFR, remained more or less the same throughout (mean of 55.86 ml/min/1.73 m² pre-operatively, 58.39 ml/min/1.73 m² on the day following OPCAB and 58.39 ml/min/1.73 m² at discharge). One patient with stage 2 CKD (0.9%) required hemodialysis post-operatively while 3 patients (1.5%) required the same in the stage 3 CKD group, which was not statistically significant. Nineteen patients (6.03%) required re-intubation for hypoxia in the post-operative period. Post-operative myocardial infarction developed in 12 patients (3.81%). Twenty patients (6.35%) patients needed an intra-aortic balloon pump (IABP) insertion in the peri-operative period owing to hemodynamic compromise. Fifteen patients (4.76%) were re-explored for bleeding following surgery and fifteen patients (4.76%) had a deep sternal wound infection in the post-operative period. New-onset atrial fibrillation was found to be present in 42 stage 3 CKD patients (11%) while it occurred in 21 stage 2 CKD patients (9.6%) (p value = 0.014), which was statistically significant. The mean duration of ITU stay was 84 ± 6.22 h in the stage 2 CKD group and 92.9 ± 8.18 h in the stage 3 CKD group (p value = 0.01), which was statistically significant. Mean duration of ITU stay was 94 ± 10.12 h in the diabetic group while it was 86.7 ± 11.08 h in the non-diabetic group (p value = 0.008) which was statistically significant. Duration of post-operative hospital stay was a mean of 8 ±0.08 days in the diabetic group whereas it was 7 ± 0.04 days in the non-diabetic group (p value = 0.012), which was statistically significant. Surgical mortality was 6 out of 315 patients (1.9%).

Conclusion

OPCAB is a safe and effective revascularization strategy in patients with stage 2 and stage 3 CKD. Short-term outcomes of OPCAB have been good in the patient population in this study, in terms of both surgical morbidity and mortality. Surgical mortality was 1.9%. New-onset atrial fibrillation was found in eleven patients (9.6%) in the stage 2 CKD group and 42 patients (21%) in the stage 3 CKD group (p value =0.014) which was statistically significant. The results of this study reflect the reno-protective nature of OPCAB. The duration of ITU stay and the post-operative duration of stay at the hospital were found to be significantly more in diabetics than in non-diabetics.

Impact of Preoperative Occult Renal Dysfunction on Early and Late Outcomes After Off-Pump Coronary Artery Bypass

BACKGROUND

Renal dysfunction is independently associated with increased early and late mortality after coronary artery bypass graft (CABG) surgery. Off-pump CABG (OPCABG) avoids postoperative complications from the cardiopulmonary bypass, but it is unclear how it is impacted by occult renal dysfunction (ORD). This study aimed to investigate the effects of ORD on early and late outcomes after OPCABG.

METHODS

This retrospective and observational cohort study reviewed data on 1,188 patients who underwent first isolated OPCABG with normal serum creatinine (SCr) levels. According to preoperative estimated creatinine clearance (eCrCl) by the Cockcroft-Gault formula, the patients were divided into an ORD group (n=260, eCrCl <60 mL/min/1.73 m²) and a control group (n=928, eCrCl ≥60 mL/min/1.73 m²).

RESULTS

The ORD patients presented with older age, higher incidence of small body surface area, hypertension, low preoperative eCrCl, cerebrovascular accident, peripheral vascular disease, New York Heart Association (NYHA) Ⅲ, and high risk score. The prevalence of hospital mortality, postoperative acute kidney injury (AKI), peak postoperative SCr, and prolonged hospital stay were greater in the ORD patients than the control patients. Multivariable logistic regression analysis showed that the ORD patients were at significantly higher risk of postoperative AKI (OR, 2.702; 95% CI, 1.994-3.662) and in-hospital mortality (OR, 2.884; 95% CI, 1.293-6.432). Multivariate Cox proportional hazard models confirmed that ORD was significantly associated with high later mortality (HR, 2.847; 95% CI, 1.262-6.425).

CONCLUSIONS

Occult renal dysfunction is an independent risk factor for postoperative AKI in-hospital and later mortality in patients undergoing OPCABG with normal SCr levels.

Comparison of the renoprotective effect of dexmedetomidine and dopamine in high-risk renal patients undergoing cardiac surgery: A double-blind randomized study

OBJECTIVE

The purpose of the current study was to compare the renoprotective effects of continuous infusion of dexmedetomidine and dopamine in high-risk renal patients undergoing cardiac surgery.

DESIGN

A double-blind randomized study.

SETTING

Cardiac Centers.

PATIENTS

One hundred and fifty patients with baseline serum creatinine level ≥1.4 mg/dl were scheduled for cardiac surgery with cardiopulmonary bypass.

INTERVENTION

The patients were classified into two groups (each = 75): Group Dex - the patients received a continuous infusion of dexmedetomidine 0.4 μg/kg/h without loading dose during the procedure and the first 24 postoperative hours and Group Dopa - the patients received a continuous infusion of dopamine 3 μg/kg/min during the procedure and the first 24 postoperative hours.

MEASUREMENTS

The monitors included serum creatinine, creatinine clearance, blood urea nitrogen, and urine output.

MAIN RESULTS

The creatinine levels and blood urea nitrogen decreased at days 1, 2, 3, 4, and 5 in Dex group and increased in patients of Dopa group (P < 0.05). The creatinine clearance increased at days 1, 2, 3, 4, and 5 in Dex group and decreased in patients of Dopa group (P < 0.05). The amount of urine output was too much higher in the Dex group than the Dopa group (P < 0.05).

CONCLUSIONS

The continuous infusion of dexmedetomidine during cardiac surgery has a renoprotective effect and decreased the deterioration in the renal function in high-risk renal patients compared to the continuous infusion of dopamine.

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.

An update on coronary artery disease and chronic kidney disease

Despite the improvements in diagnostic tools and medical applications, cardiovascular diseases (CVD), especially coronary artery disease (CAD), remain the most common cause of morbidity and mortality in patients with chronic kidney disease (CKD). The main factors for the heightened risk in this population, beside advanced age and a high proportion of diabetes and hypertension, are malnutrition, chronic inflammation, accelerated atherosclerosis, endothelial dysfunction, coronary artery calcification, left ventricular structural and functional abnormalities, and bone mineral disorders. Chronic kidney disease is now recognized as an independent risk factor for CAD. In community-based studies, decreased glomerular filtration rate (GFR) and proteinuria were both found to be independently associated with CAD. This paper will discuss classical and recent epidemiologic, pathophysiologic, and clinical aspects of CAD in CKD patients.

Does chronic kidney disease affect outcomes after major abdominal surgery? Results from the National Surgical Quality Improvement Program

INTRODUCTION

The impact of chronic kidney disease (CKD) and end-stage renal disease on outcomes following major abdominal surgery is not well defined.

MATERIALS AND METHODS

The 2008 NSQIP database was queried to identify adult patients undergoing complex abdominal surgery (major colorectal, hepatobiliary, pancreatic, gastric, and esophageal operations). Thirty-day morbidity and mortality in patients on hemodialysis (HD) versus patients not on HD were compared. The impact of preoperative renal insufficiency, measured by glomerular filtration rate (GFR), on morbidity and mortality was then assessed in non-dialysis patients.

RESULTS

Of 24,572 patients who underwent major abdominal operations, excluding emergency cases, only 149 (0.6%) were on HD preoperatively. Thirty-day mortality in the HD group was 12.8% compared to 1.8% for those not on HD (p < 0.0001). Overall complication rate was 23.5 versus 12.3% (p < 0.0001). In particular, rates of pneumonia (6.7 vs 3.0%, p < 0.05) and sepsis (12.8 vs 5.3%, p < 0.001) were higher in patients on HD. In patients not on HD, GFR was significantly predictive of postoperative mortality after controlling for age, gender, race, emergency status, and comorbidities. Compared to patients with normal preoperative kidney function (GFR, 75-90 ml/min/1.73 m(2)), even modest CKD (GFR, 45-60 ml/min/1.73 m(2)) was associated with increased postoperative mortality (odds ratio (OR), 1.62). With greater impairment in kidney function, postoperative mortality was even more marked (GFR, 30-45 ml/min/1.73 m(2) and OR, 2.84; GFR, 15-30 ml/min/1.73 m(2) and OR, 5.56). In addition, CKD was independently associated with increased postoperative complications.

CONCLUSION

Any degree of preoperative kidney impairment, even mild asymptomatic disease, is associated with clinically significant increases in 30-day postoperative morbidity and mortality following major abdominal surgery.

Preoperative estimated glomerular filtration rate as a significant predictor of long-term outcomes after coronary artery bypass grafting in Japanese patients

PURPOSES

The aim of this retrospective study was to investigate the effect of chronic kidney disease (CKD) on outcomes after coronary artery bypass grafting (CABG), and to determine whether preoperative estimated glomerular filtration rate (eGFR) can be a predictor of long-term outcomes after CABG.

METHODS

486 Japanese patients who underwent isolated CABG between December 2000 and August 2010 were evaluated. Preoperative eGFR was estimated by the Japanese equation according to guidelines from the Japanese Society of Nephrology. We defined CKD as a preoperative eGFR of less than 60 ml/min/1.73 m(2). 203 patients had CKD (CK group) and 283 patients did not (N group).

RESULTS

During a mean observation time of 53 months, the overall survival rate was significantly lower in the CK group than in the N group (p = 0.0044). Similarly, the CK group had significantly more unfavorable results with regard to freedom from cardiac death, major adverse cardiovascular and cerebrovascular events (MACCE), and hemodialysis. Using multivariate analyses, preoperative eGFR was an independent predictor of all-cause mortality (HR 0.983; p = 0.026), cardiac mortality (HR 0.963; p = 0.006), and incidence of MACCE (HR 0.983; p = 0.002).

CONCLUSIONS

The CK group had significantly more unfavorable outcomes than the N group. Preoperative eGFR was an independent predictor of long-term outcomes after CABG in Japanese patients.

Preoperative renal dysfunction and clinical outcomes of cardiac surgery in octogenarians

BACKGROUND

The proportion of elderly individuals is growing and the prevalence of chronic kidney disease (CKD) among elderly people undergoing cardiac surgery is increasing constantly. The aim of this study was to determine the influence of different degrees of preoperative renal dysfunction on postoperative outcomes in patients older than 80years of age.

METHODS

This is an observational study that included adult patients undergoing cardiac surgery in which data were collected prospectively. Patients were divided into groups according to their preoperative plasma creatinine and eGFR levels.

RESULTS

From February 1997 to January 2010, 318 octogenarians underwent cardiac surgery. Of these, 140 patients (44%) had abnormal preoperative creatinine levels. A significantly higher incidence of postoperative sepsis (4% vs. 17%, p 0.03), CVA (1% vs. 6%, p 0.03), and prolonged hospital stay (16±13 vs. 20±16days, p 0.04) were detected in patients with preoperative kidney dysfunction. Subgroup analysis revealed that preoperative CKD stage IV (eGFR 15-30ml/min/1.73m(2)) but not CKD stage III (eGFR 30-60ml/min/1.73m(2)) and preoperative creatinine >1.8mg/dl were independently associated with increased incidence of postoperative CVA (OR 4; 95% CI 0.07-0. 8, p=0.05 for eGFR, and OR 7.8; 95% CI 1.2-60, p=0.003 for creatinine). However, no significant increment in postoperative mortality with decreasing eGFR or increasing preoperative creatinine was demonstrated.

CONCLUSIONS

A substantial increase in the risk of postoperative CVA and sepsis, but not mortality, was demonstrated in octogenarians with advanced but not mild degrees of preoperative CKD. Compared to younger patients, a high burden of comorbidities in octogenarians may have a greater influence on outcomes post cardiac surgery than impaired renal function. Our data may provide a rationale for modified risk stratification in octogenarian candidates for cardiac surgery.

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.

The impact of off-pump coronary artery bypass surgery on postoperative renal function

OBJECTIVES

A number of risk factors have been recognised for postoperative renal dysfunction following on-pump coronary artery bypass surgery (CABG). There are, however, few studies that have evaluated the potential reno-protective effects of off-pump CABG in the presence of other confounding risk factors. The aim of this study was to determine if off-pump CABG reduces the risk of renal injury.

METHODS

Serum creatinine values (preoperatively and day 1, 2 and 4 postoperatively) and other clinical data were prospectively collected on 1580 consecutive patients who underwent first-time CABG from 2002 to 2005. Creatinine clearance was calculated using the Cockcroft and Gault equation. The effect of on-pump vs. off-pump CABG on renal function was analysed, adjusting for age, gender, diabetes mellitus, left ventricular (LV) function and preoperative creatinine clearance, using multiple regression analysis.

RESULTS

One thousand one hundred and forty-five (73%) patients underwent on-pump CABG and 435 (27%) underwent off-pump CABG. The two groups were similar with respect to age, gender and diabetes. Two hundred and seventy-four (17%) patients were females and 274 (17%) patients had diabetes. Multivariate analysis demonstrated significantly lower creatinine clearance postoperatively in patients with diabetes (P<0.001) and advanced age (P<0.001). The on-pump group had significantly lower postoperative creatinine clearance in comparison to the off-pump group (P= 0.01). The effect remained consistent after adjusting for potential risk factors (age, diabetes, gender, LV function and preoperative creatinine clearance) in the multivariate analysis.

CONCLUSION

Off-pump surgery is associated with a reduction in postoperative renal injury.

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.

Coronary revascularisation in chronic kidney disease. Part 1: stable coronary artery disease

Chronic kidney disease (CKD) is associated with a high burden of coronary artery disease, myocardial infarction and cardiovascular death. Detection and treatment of coronary artery disease in CKD patients has been hampered by the limitations of screening tests, the lack of direct evidence for therapeutic interventions in this specific population, and concerns about therapy-related adverse effects. However, these patients potentially have much to gain from conventional strategies used in the general population. This review summarises the current evidence regarding the treatment of coronary artery disease in patients with CKD, with the focus on coronary revascularisation by percutaneous coronary intervention or coronary artery bypass grafting.

Occult renal dysfunction: a mortality and morbidity risk factor in coronary artery bypass grafting surgery

OBJECTIVE

Elevated preoperative serum creatinine is considered an independent risk factor for postoperative mortality and morbidity in patients undergoing coronary artery bypass grafting. However, the impact of occult renal dysfunction, defined as an impairment of glomerular filtration rate with normal serum creatinine, is still unknown. The aim of this study was to analyze the effects of occult renal dysfunction on early outcomes after coronary artery bypass grafting.

METHODS

This was a retrospective, observational, cohort study of prospectively collected data on 9159 consecutive patients with normal serum creatinine levels undergoing coronary artery bypass grafting between April 1996 and February 2009. Patients were divided into two groups based on preoperative creatinine clearance estimated with the Cockcroft-Gault equation: 5484 patients with a creatinine clearance ≥ 60 mL/min and 3675 patients with a creatinine clearance < 60 mL/min (occult renal dysfunction group).

RESULTS

Overall in-hospital mortality was 1%. Occult renal dysfunction was associated with a doubling in the risk of operative mortality (1.4% vs 0.7%; P = .001), postoperative renal dysfunction (5.1% vs 2.5%; P < .0001), and need for dialysis (0.8% vs 0.4%; P = .014). Moreover, occult renal dysfunction increased the risk of stroke (1% vs 0.3%; P < .0001), arrhythmia (28.5% vs 21.2%; P < .0001), and hospital stay > 7 days (36.45 vs 24.5%; P < .0001). In a multivariable analysis adjusting for preoperative risk factors, occult renal dysfunction was confirmed to be an independent predictor of mortality (odds ratio, 1.72), postoperative renal dysfunction (odds ratio, 1.9), dialysis (odds ratio, 1.82), stroke (odds ratio, 2.6) arrhythmia (odds ratio, 1.42), and hospital stay > 7 days (odds ratio, 1.65).

CONCLUSIONS

Occult renal dysfunction is an independent risk factor for early mortality and morbidity in patients undergoing coronary artery bypass grafting.

Impact of preoperative mild renal dysfunction on short term outcome in isolated Coronary Artery Bypass (CABG) patients

BACKGROUND AND AIM

It is well known that dialysis dependent renal failure increases the likelihood of poor outcome following cardiac surgery. But the results of CABG in patients with mild renal dysfunction are not clearly established. The aim of the study is to analyze the risk of preoperative mild renal dysfunction on outcome after isolated coronary surgery.

MATERIALS AND METHODS

We reviewed prospectively collected data between June 2006-Nov 2006 in 488 patients who underwent isolated CABG. We separated the data into two groups. Control group having normal renal function and study group having mild renal dysfunction (serum creatinine 1.4 mg-2.2 mg%). Among 488 patients, 412 patients were in control group and 76 patients were in the study group.

RESULTS

Analysis of data showed significant postoperative complications in the mild renal dysfunction group, like increased operative mortality (7.5% vs 1.6%), increased requirement of postoperative renal replacement therapy (10% vs 1.2%), increased incidence of new onset atrial fibrillation (20% vs 4.2%) and prolonged duration of ICU stay. Multivariate analysis adjusting for known risk factors confirmed preoperative mild renal dysfunction (S.creat.1.4-2.2 mg/dl) is an independent risk factor for postoperative morbidity and mortality. (Adj. OR: 4.47; 95% CI: 1.41-14.16; P=0.010).

CONCLUSION

Mild renal dysfunction is an important independent predictor of outcome in terms of in-hospital mortality and morbidity in patients undergoing CABG.

Preoperative renal function as a predictor of survival after coronary artery bypass grafting: comparison with a matched general population

OBJECTIVE

Preoperative renal dysfunction is an established risk factor for early and late mortality after revascularization. We studied how renal function affects long-term survival of patients after coronary artery bypass grafting.

METHODS

Early and late mortality were determined retrospectively among consecutive patients having isolated coronary bypass at a single Dutch institution between January 1998 and December 2007. Patients were stratified into 4 groups according to preoperative renal function. Expected survival was gauged using a general Dutch population group that was obtained from the database of the Dutch Central Bureau for Statistics; for each of our renal function groups, a general population group was assembled by matching for age, gender, and year of operation.

RESULTS

After excluding 122 patients lost to follow-up, 10,626 patients were studied; in 10,359, preoperative creatinine clearance could be calculated. Multivariate logistic regression and Cox regression analysis identified renal dysfunction as a predictor for early and late mortality. When long-term survival of patient groups was compared with expected survival, only patients with a creatinine clearance less than 30 mL x min(-1) showed a worse outcome. Patients with a creatinine clearance between 60 and 90 mL x min(-1) had a long-term survival exceeding the expected survival.

CONCLUSIONS

Severity of renal dysfunction was related to poor survival. When compared with expected survival, however, patients having coronary bypass had a worse outcome only when severe preoperative renal dysfunction was present.

Impact of renal dysfunction on long-term survival after isolated coronary artery bypass surgery

BACKGROUND

Preoperative renal dysfunction has been an important predictor for adverse cardiovascular events after coronary artery bypass grafting (CABG). In the past, serum creatinine was widely used to assess renal function. Until recently, estimated glomerular filtration rate (eGFR) was recommended in evaluating renal function. The Cockcroft-Gault formula and the Modification of Diet in Renal Disease (MDRD) equation are two widely used formulas in clinical practice. Which method best predicts long-term outcome after CABG is still unknown. This study compared the predictive effectiveness of the Cockcroft-Gault formula, the MDRD equation, and serum creatinine level for in-hospital and long-term mortality.

METHODS

We retrospectively reviewed data collected from 5559 patients who underwent isolated CABG at Fuwai Hospital from January 1999 to December 2005. The main outcomes were in-hospital and long-term mortality. Receiver operating characteristic (ROC) curves and Cox analysis were used for the comparison.

RESULTS

Mean follow-up was 56.5 +/- 24.6 months. ROC curve analysis showed that the Cockcroft-Gault formula had the greatest accuracy for predicting in-hospital mortality (area under the curve, 0.755; p < 0.001). Multivariate analysis confirmed that the eGFR based on the Cockcroft-Gault formula was an independent predictor of in-hospital (odds ratio, 4.51, p < 0.001) and long-term (hazard ratio, 1.54; p = 0.003) mortality. Both formulas were better than the serum creatinine level.

CONCLUSIONS

Both formulas could provide a better measure of risk assessment than serum creatinine for in-hospital and long-term mortality. The Cockcroft-Gault formula was better than the MDRD equation for predicting in-hospital mortality.

The relationship between renal function and outcome from heart valve surgery

BACKGROUND

The prognostic importance of renal function in patients undergoing surgery for valvular heart disease is poorly defined. The current study addresses this issue.

METHODS

Baseline demographic and clinical variables, including the European system for cardiac operative risk evaluation (EuroSCORE), were recorded prospectively from 514 consecutive patients undergoing heart valve surgery between April 2000 and March 2004. Patients with active infective endocarditis and/or requiring emergency surgery were excluded. The glomerular filtration rate was estimated (eGFR) using the Modification of Diet in Renal Disease equation. The primary outcome was all-cause mortality.

RESULTS

During a median follow-up of 2 years, 87 patients died. In univariable analysis, both eGFR (hazard ratio [HR] 0.69 per 10 mL/min per 1.73 m2, P<.001) and creatinine (HR 1.04 per 10 micromol/L, P<.001) predicted mortality. Estimated GFR was a stronger predictor and was used in subsequent multivariable models. It remained a powerful independent predictor of death in a multivariable model including all study variables (HR 0.70 per 10 mL/min per 1.73 m2 increase, P<.001) and in a model including EuroSCORE (HR 0.64 per 10 mL/min per 1.73 m2 increase, P<.001). After correction for preoperative EuroSCORE, an eGFR of <60 mL/min per 1.73 m2 was associated with an excess hazard of death of 2.31 (P=.001).

CONCLUSION

Renal function, particularly the eGFR, is a powerful predictor of outcome in patients undergoing heart valve surgery. This prognostic utility is independent of other recognized risk factors and the EuroSCORE.

Severity of chronic kidney disease as a risk factor for operative mortality in nonemergent patients in the California coronary artery bypass graft surgery outcomes reporting program

Guidelines published by the National Kidney Foundation in 2002 categorize renal failure into 5 stages of increasing severity. The relation of this classification to risk stratification for operative mortality in patients with nonemergent coronary artery bypass grafting (CABG) has not been clarified. We examined the effect of chronic kidney disease (CKD) severity on CABG operative mortality in patients with nonemergent CABG. Data reporting to the California CABG outcomes reporting program is mandated in California. Data from 121 hospitals on patients undergoing CABG in 2003 and 2004 were analyzed, including clinical characteristics, CKD stage, and operative mortality. CKD stage 1 and 2 were combined to form the reference group because data on urinary markers of renal failure were not available. Excluding patients with emergent or salvage acuity for CABG, 37,735 isolated CABGs were performed. Of these, 27,132 patients (71.9%) had glomerular filtration rate (GFR)>or=60 ml/min/1.73 m2; 8,861 (23.5%) had stage 3 CKD (GFR 30 to 59); 669 (1.8%) had stage 4 CKD (GFR 15 to 29); and 1,073 (2.8%) had stage 5 CKD (GFR<15 or on dialysis). In separate multivariate analyses, GFR and CKD stage were each significantly and independently associated with operative mortality (both p<0.0001). Operative mortality increased significantly with each stage of CKD (all p<0.01). Compared with the reference group, stage 3, (odds ratio [OR] 1.18, p=0.0374), stage 4 (OR 2.23, p<0.0001), and stage 5 (OR 4.39, p<0.0001) had increasingly higher operative mortality. In conclusion, CKD stage based on National Kidney Foundation guidelines is an important predictor in risk stratification for operative mortality in patients undergoing nonemergent CABG.

Renal function after cardiopulmonary bypass surgery in patients with impaired renal function. A randomized study of the effect of nifedipine

BACKGROUND AND OBJECTIVES

Postoperative acute renal failure predicts morbidity and mortality. We investigated the effect of nifedipine infusion on glomerular filtration rate in patients with impaired renal function undergoing cardiopulmonary bypass surgery.

METHODS

Twenty patients accepted for coronary bypass and/or heart valve surgery were enrolled prospectively and randomized to nifedipine infusion or no treatment. Males and females with creatinine 150 micromol L(-1) and 130 micromol L(-1), respectively, were included. Patients with unstable angina pectoris, ejection fraction 35% and those on dialysis were excluded. Glomerular filtration rate was measured preoperatively and 48 h postoperatively. Creatinine clearance was measured preoperatively and 0-4, 20-24 and 44-48 h postoperatively. There were no statistically significant differences in patient characteristics. Biochemical markers in plasma and urine were measured before and 48 h after surgery.

RESULTS

The mean +/- SD preoperative glomerular filtration rates were 32.2 +/- 11.5 and 31.4 +/- 17.0 mL min-1 per 1.73 m2 in the nifedipine and control groups (P = 0.90), respectively. There was no statistically significant change in the glomerular filtration rate or in creatinine clearance over time within or between groups. A linear mixed model showed no effect of nifedipine (P = 0.44), time (P = 0.97) or interaction of nifedipine and time (P = 0.99) on creatinine clearance. Perioperative arterial pressure was kept within predefined targets. Three patients received dialysis postoperatively, all in the control group (P = 0.21). There were no statistically significant differences between groups in changes of urinary or plasma biochemistry.

CONCLUSIONS

Renal function was well preserved after cardiopulmonary bypass surgery in patients with impaired renal function when maintaining thorough intensive care surveillance. Nifedipine did not influence early postoperative renal function.

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.

Coronary artery bypass grafting with or without cardiopulmonary bypass in patients with preoperative non–dialysis dependent renal insufficiency: A randomized study

OBJECTIVE

Preoperative renal insufficiency is a predictor of acute renal failure in patients undergoing coronary artery revascularization with cardiopulmonary bypass. Off-pump coronary artery bypass grafting has been shown to be less deleterious than on-pump bypass in patients with normal renal function, but the effect of this technique in patients with non-dialysis dependent renal insufficiency in a randomized study is unknown.

METHODS

From August 2004 through October 2005, 116 consecutive patients with preoperative non-dialysis-dependent renal insufficiency (glomerular filtration rate measured using the Modification of Diet in Renal Disease equation [MDRD GFR] < or = 60 mL x min(-1) x 1.73 m(-2)) undergoing primary coronary artery bypass grafting were randomized to on-pump (n = 60) and off-pump (n = 56) groups. MDRD GFR and serum creatinine levels were measured preoperatively and postoperatively at days 1 and 5. The changes in renal function and clinical outcomes were compared between the two groups.

RESULTS

Preoperative characteristics were comparable between the two groups. The repeated-measures analysis of variance was performed on the data that showed worsening of renal function in the on-pump group compared with the off-pump group (serum creatinine, P < .000; glomerular filtration rate, P < .000). Further analysis of subgroups of patients with diabetes alone, hypertension alone, and combined hypertension and diabetes also showed significant deterioration renal function in the on-pump group compared with the off-pump group. In covariate analysis, diabetes has emerged as a significant covariate by serum creatinine criteria while compromised left ventricular function has emerged as a significant covariate by glomerular filtration rate criteria. These analyses showed that the use of cardiopulmonary bypass is significantly associated with adverse renal outcome (P < .000). Three patents required hemodialysis in the on-pump group and none in the off-pump group. The mean number of grafts per patient was 3.85 +/- 0.86 and 3.11 +/- 0.89 in the on-pump and off-pump groups, respectively (P < .001), but the indices of completeness of revascularization, 1.00 +/- 0.08 for off-pump coronary bypass and 1.01 +/- 0.08 for on-pump coronary bypass, were similar (P = .60).

CONCLUSIONS

This study suggests that on-pump as compared with off-pump coronary artery bypass grafting is more deleterious to renal function in diabetic patients with non-dialysis dependent renal insufficiency. MDRD GFR is a more sensitive investigation than serum creatinine levels to assess renal insufficiency in patients undergoing coronary bypass.

Prophylactic Dialysis in Elderly Patients Undergoing Coronary Bypass Surgery

Renal dysfunction is associated with markedly increased risk for both mortality and morbidity in patients undergoing coronary artery bypass surgery (CABG), especially in elderly patients. In the current study, we aimed to determine the impact of prophylactic preoperative hemodialysis on operative outcome in patients with mild renal dysfunction. Between March 2002 and May 2005 a total of 64 patients, all of whom were more than 70 years of age and with preoperative creatinine levels greater than 2 mg/dL, underwent primary elective on pump coronary artery bypass surgery. The mean age was 76.3 +/- 6.4 (range 70-83). The patients were prospectively allocated into two groups. Group A was the dialysis group (31 patients) and preoperative prophylactic hemodialysis was carried out in all patients. Group B (33 patients) was taken as a control group without preoperative hemodialysis. During the present study, 10 patients died (15.6%) in the hospital. In the postoperative period mean levels of creatinine were found to be decreased in dialysis group. (2.3 +/- 0.8 mg/dL vs. 3.4 +/- 0.2 mg/, P = 0.037). The incidence of overall morbidity (such as acute renal failure, need of postoperative dialysis, low cardiac output and multiple organ failure) were also found to be decreased in dialysis group. We conclude from the present study that preoperative renal dysfunction and advanced age increase the risk of mortality and morbidity after on-pump coronary artery bypass surgery. We believe that perioperative prophylactic hemodialysis is an easy and effective method and it decreases both operative mortality and morbidity in elderly patients with renal dysfunction.

Cardiopulmonary bypass and renal injury

Renal dysfunction following cardiopulmonary bypass (CPB) is well recognized. The extent of perioperative renal impairment ranges from subclinical injury to established renal failure requiring dialysis. Its incidence varies considerably, depending on the definition and criteria used in the different studies. Acute renal failure (ARF) affects 1-5% of patients and remains a major cause of morbidity and mortality. Co-morbidities, including diabetes mellitus, impaired left ventricular function and advanced age, are recognized predisposing factors. The pathophysiology is multifactorial and is thought related to the systemic inflammatory response and renal hypoperfusion secondary to extracorporeal circulation. Non-pulsatile flow during CPB is thought to be an important aetiological factor, resulting in renal vasoconstriction and ischaemic renal injury. A theoretical reduction in the incidence and severity of postoperative renal impairment has been proposed by advocating the use of pulsatile flow during CPB, or eliminating CPB, especially in high-risk patients. The current evidence, however, is conflicting. Several large observational studies, including a large proportion of high-risk patients, have demonstrated a significant reduction in the frequency of renal failure in patients undergoing off-pump surgery. As older, sicker patients increasingly constitute the cardiac surgical population, the incidence of postoperative renal injury is likely to increase. Further studies addressing various renoprotective strategies in higher-risk patients are awaited.

How safe is it to train residents to perform off-pump coronary artery bypass surgery?

BACKGROUND

The technique of off-pump coronary artery bypass graft (OPCABG) surgery differs considerably from on-pump CABG. This study investigates the impact of surgical training on clinical outcome in patients undergoing OPCABG.

METHODS

All 251 OPCABG cases performed by one service over an 18-month period were analyzed. The 83 operations (33%) performed by two trainees under supervision were compared with the 168 operations (67%) performed by an experienced consultant surgeon. Patient and disease characteristics, intraoperative and postoperative data, morbidity and mortality were analyzed using univariate and multivariate analysis. Data were extracted from a prospective database.

RESULTS

Patients operated on by the consultant were more likely to have had unstable angina (p = 0.003, odds ratio [OR] = 3.5), impaired left ventricular function (ejection fraction < 0.3; p = 0.005, OR = 2.4), or previous cardiac surgery (p = 0.03). They were more likely to receive three or more grafts (p = 0.017, OR = 2.0). Operative mortality was 2.4% (consultant) and 0% (trainees; p = 0.31). Postoperative morbidity, such as reoperation for bleeding (consultant 3% versus trainees 1.2%), stroke (0.6% versus 1.2%), and hemofiltration (3.6% versus 0%) was similar between the two patient groups. Stay in the intensive care unit was not significantly different in the two groups.

CONCLUSIONS

In our experience, trainee surgeons are less likely to operate on patients with unstable angina or cardiac dysfunction. Operative morbidity and mortality are, however, similar in patients operated on by either an experienced consultant surgeon or trainees. We believe OPCABG can be taught safely to trainees under supervision.

Perioperative increases in serum creatinine are predictive of increased 90-day mortality after coronary artery bypass graft surgery

BACKGROUND

Impaired renal function after coronary artery bypass graft (CABG) surgery is a key risk factor for in-hospital mortality. However, perioperative increases in serum creatinine and the association with mortality has not been well-studied. We assessed the hypothesis that perioperative increases in creatinine are associated with increased 90-day mortality.

METHODS AND RESULTS

We studied 1391 patients in northern New England undergoing CABG in 2001 and evaluated preoperative and postoperative creatinine. Patients with preoperative dialysis were excluded. Data were linked to the National Death Index to assess 90-day survival. Kaplan-Meier and log-rank techniques were used. Patients were stratified by percent increase in creatinine from baseline: <25%, 25% to 49%, 50% to 99%, > or =100%. We assessed 90-day survival and calculated adjusted hazard ratios (HR) and 95% confidence intervals (95% CI) for creatinine groups, adjusting for age and sex. Patients with the largest creatinine increases (50% to 99% or > or =100%) had significantly higher 90-day mortality compared with patients with a smaller increase (<50%; P<0.001). Adjusted HR and 95% CI confirmed patients in the higher 2 groups had an increased risk of mortality compared with the <25% (referent); however, the 25% to 49% group was not different from the referent: 1.80 (95% CI: 0.73 to 4.44), 6.57 (95% CI, 3.03 to 14.27), and 22.10 (95% CI, 11.25 to 43.39).

CONCLUSIONS

Patients with large creatinine increases (> or = 50%) after CABG surgery have a higher 90-day mortality compared with patients with small increases. Efforts to identify patients with impaired renal function and to preserve renal function before cardiac surgery may yield benefits for patients in the future.

Renal Function and Outcome From Coronary Artery Bypass Grafting

Background— Severe renal dysfunction is associated with a worse outcome after coronary artery bypass graft surgery (CABG). Less is known about the effects of milder degrees of renal impairment, and previous studies have relied on levels of serum creatinine, an insensitive indicator of renal function. Recent studies have suggested that estimated glomerular filtration rate (eGFR) is a more discriminatory measure. However, data on the utility of eGFR in predicting outcome from CABG are limited.

Methods and Results— We studied 2067 consecutive patients undergoing CABG. Demographic and clinical data were collected preoperatively, and patients were followed up a median of 2.3 years after surgery. Estimated GFR was calculated from the Modification of Diet in Renal Disease equation. The primary outcome was all-cause mortality. Mean±SD eGFR was 57.9±17.6 mL/min per 1.73 m 2 in the 158 patients who died during follow-up compared with 64.7±13.8 mL/min per 1.73 m 2 in survivors (hazard ratio [HR], 0.71 per 10 mL/min per 1.73 m 2 ; 95% CI, 0.64 to 0.80; P <0.001). Estimated GFR was an independent predictor of mortality in both models with other individual univariable predictors (HR, 0.80 per 10 mL/min per 1.73 m 2 ; 95% CI, 0.72 to 0.89; P <0.001) and the European system for cardiac operative risk evaluation (HR, 0.88 per 10 mL/min per 1.73 m 2 ; 95% CI, 0.78 to 0.98; P =0.02).

Conclusions— Estimated GFR is a powerful and independent predictor of mortality after CABG.