Renal failure predisposes patients to adverse outcome after coronary artery bypass surgery. VA Cooperative Study #5

Creatinine Reduction Ratio Is a Prognostic Factor for Acute Kidney Injury following Cardiac Surgery with Cardiopulmonary Bypass: A Single-Center Retrospective Cohort Study

Acute kidney injury (AKI) after cardiac surgery is a common complication that can lead to death. We previously reported that the creatinine reduction ratio (CRR) serves as a useful prognostic factor for AKI. The primary objective of this study was to determine the predictors of AKI after surgery. The secondary objective was to determine the reliability of the CRR for short- and long-term outcomes. We retrospectively collected information about cardiac surgery patients who underwent cardiopulmonary bypass. Patients were divided into AKI and non-AKI groups based on the AKIN and RIFLE criteria. We analyzed the two groups regarding the preoperative patient data and operative information. The CRR was calculated as follows: (preoperative creatinine-postoperative creatinine)/preoperative creatinine. The prognostic factors of AKI-CS were surgery time, CPB time, aorta clamp time, platelet transfusion, and CRR < 20%. In the multivariate logistical analysis, CRR was an independent predictor of AKI (adjusted odds ratio: 0.90 [0.87-0.93], p < 0.001). However, there were no significant differences in CRR in terms of the rate of new onset chronic kidney disease (CKD). After cardiac surgery with cardiopulmonary bypass, CRR has good diagnostic power for predicting perioperative AKI. However, we cannot use it as a prognostic factor over a long-term period.

Impact of Chronic Kidney Disease on Clinical Outcomes during Hospitalization and Five-Year Follow-Up after Coronary Artery Bypass Grafting

Background

Chronic kidney disease (CKD) is often associated with multiple comorbidities including diabetes mellitus, and each has its own complications and impact after cardiac surgery including coronary revascularization. The objective of this work was to study the impact of CKD on clinical outcomes after coronary artery bypass grafting (CABG) and to compare outcomes in patients with different grades of renal functions. We retrospectively reviewed all patients who underwent CABG from January 2016 to August 2020 at our tertiary care hospital using electronic medical records.

Results

The study included 410 patients with a median age of 60 years, and 28.6% of them had CKD and hospital mortality of 2.7%. About 71.4% of the patients had GFR > 60 mL/min per 1.73 m2, 18.1% had early CKD (GFR 30-60), 2.7% had late CKD (GFR < 30), and 7.8% of them had end-stage renal disease (ESRD) requiring dialysis. The CKD group had significantly more frequent hospital mortality (p = 0.04), acute cerebrovascular stroke (p = 0.03), acute kidney injury (AKI) (p < 0.001), longer ICU stay (p = 0.002), post-ICU stay (p = 0.001), and sternotomy wound debridement (p = 0.03) compared to the non-CKD group. The frequencies of new need for dialysis were 2.4% vs. 14.9% vs. 45.5% (p < 0.001) in the patients with GFR > 60 mL/min per 1.73 m2, early CKD, and late CKD, respectively. Acute cerebral stroke (OR: 10.29, 95% CI: 1.82-58.08, and p = 0.008), new need for dialysis (OR: 25.617, 95% CI: 13.78-85.47, and p < 0.001), and emergency surgery (OR: 3.1, 95% CI: 1.82-12.37, and p = 0.036) were the independent predictors of hospital mortality after CABG. The patients with CKD had an increased risk of strokes (HR: 2.14, 95% CI: 1.20-3.81, and p = 0.01) but insignificant mortality increase (HR: 1.44, 95% CI: 0.42-4.92, and p = 0.56) during follow-up.

Conclusion

The patients with CKD, especially the late grade, had worse postoperative early and late outcomes compared to non-CKD patients after CABG. Patients with dialysis-independent CKD had increased risks of needing dialysis, hospital mortality, and permanent dialysis after CABG.

Single Versus Multiple Arterial Revascularization in Patients With Reduced Renal Function: Long-term Outcome Comparisons in 23,406 CABG Patients From Ontario, Canada

OBJECTIVE

To compare the long-term outcomes of MAR versus SAR in patients with renal insufficiency.

SUMMARY OF BACKGROUND DATA

Previous studies have been insufficiently powered to address whether MAR confers long-term benefit over SAR in patients with renal dysfunction who require CABG.

METHODS

We conducted retrospective cohort study in Ontario, Canada of patients who underwent isolated CABG (n = 23,406). The primary outcome was MACE, defined as the composite of stroke, myocardial infarction, and repeat revascularization. We compared patients by matching them on the propensity to have received SAR versus MAR, within groups with preoperative glomerular filtration rate (GFR) ≥60 mL/min/1.73 m2; GFR between 30 and 60; and GFR <30.

RESULTS

In patients with GFR ≥60, the use of MAR versus SAR was associated with a lower rate of MACE [hazard ratio (HR) 0.87 (0.80-0.94)], and a lower rate of long-term mortality [HR 0.87 (0.79-0.97)]. In those with GFR between 30 and 60, MAR was not associated with a difference in MACE [HR 1.04 (0.87-1.26)], and a lower rate of long-term mortality [HR 0.75 (0.65-0.87)] was observed. In those with GFR <30, MAR was not associated with a difference in outcomes.

CONCLUSIONS

MAR versus SAR does not correlate with a difference in MACE amongst patients with GFR between 30 and 60 and better survival raises the possibility of indication bias. Furthermore, MAR did not confer a benefit in those with severely reduced renal function. These data suggest that the potential long-term benefits of using MAR in CABG patients with renal insufficiency may be offset by competing health risks.

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.

Hepatorenal dysfunction assessment with the Model for End-Stage Liver Disease Excluding INR score predicts worse survival after heart transplant in pediatric Fontan patients

BACKGROUND

Fontan physiology results in multiorgan dysfunction, most notably affecting the liver and kidney. We evaluated the utility of Model for End-Stage Liver Disease Excluding INR (MELD-XI) score, a score evaluating the function of both liver and kidney to identify Fontan patients at increased risk for morbidity and mortality post-heart transplant.

METHODS

The Pediatric Heart Transplant Society database was queried to identify Fontan patients listed for heart transplant between January 2005 and December 2018. MELD-XI scores were calculated at listing and heart transplant. A multivariable analysis was conducted to identify risk factors for post-heart transplant mortality. Demographic, clinical characteristics, and survival differences were evaluated and compared between the high and low MELD-XI score cohorts. The impact of changing MELD-XI scores during the waitlist period on post-heart transplant outcomes was also evaluated.

RESULTS

Of 565 Fontan patients who underwent transplantation, 524 (93%) had calculable MELD-XI scores at the time of heart transplant: 421 calculable at listing and 392 calculable at listing and at heart transplant. On multivariable analysis, only MELD-XI score (squared) (hazard ratio, 1.007), history of protein-losing enteropathy (hazard ratio, 2.1), and ventricular assist device use at transplant (hazard ratio, 3.4) were risk factors for early phase post-heart transplant mortality. Patients with high MELD-XI scores at heart transplant had inferior survival post-heart transplant (P = .02); those in the high MELD-XI score cohort at wait listing and heart transplant tend to have the worst post-heart transplant survival; however, this was not significant (P = .42).

CONCLUSIONS

The MELD-XI, an easily calculated score, serves as a valuable aid in identifying pediatric Fontan patients at increased risk for post-heart transplant mortality.

Renal insufficiency and severe coronary artery disease: should coronary artery bypass grafting, off-pump coronary artery bypass grafting or percutaneous coronary intervention be performed?

PURPOSE OF REVIEW

Chronic kidney disease (CKD) is an important determinant of long-term survival. However, the optimal revascularization strategy for patients with CKD is still controversial. Herein we review the impact of different treatment modalities on the outcomes of patients with CKD.

RECENT FINDINGS

CABG could confer better long-term outcomes than PCI in patients with CKD, irrespective of CKD severity. CABG as compared with PCI may be associated with improved long-term survival albeit higher short-term risk. Off-pump as compared with on-pump CABG may be associated with better short-term outcomes but no demonstrable long-term benefit. In CKD patients who are treated with PCI, the use of drug-eluting stents may be associated with better intermediate-term outcomes than bare metal stents.

SUMMARY

There is insufficient evidence to inform the optimal revascularization strategy for patients with CKD and severe coronary artery disease. CABG as compared with PCI confers greater long-term benefit but higher upfront risk. A multidisciplinary, team-based evaluation based on individual patient comorbidity, frailty and anatomical disease burden, is recommended when making treatment decisions.

Mid-Term Outcomes of Primary Hip Replacement in Patients with End-Stage Chronic Renal Disease

Purpose — to evaluate mid-term outcomes of primary hip replacement in patients with end-stage chronic renal disease and to develop an algorithm for selection of surgical tactics and perioperative treatment.

Materials and Methods. The authors evaluated outcomes of primary hip replacement in 45 patients receiving renal substitution therapy and 47 patients without chronic renal disease. Patients with end-stage chronic renal disease (CRD) were divided into two groups: group I included 30 (66.6%) patients receiving chronic hemodialysis (CH) and group II included 15 (33.4%) patients after renal transplantation (RT). Group III of 47 (51.1%) patients without any signs of CRD who underwent hip arthroplasty within relevant period of time was established to evaluate the effectiveness of primary hip replacement. Blood serum Ca2+ and P5+ levels as well as levels of parathyroid hormone (PTH) and 1.25-dihydroxyvitamin D were measured to determine the rate of calcium- phosphoric metabolism disturbance. Multi-spiral CT scans of hip joint were performed to identify bone mineral density and the mean Hounsfield (Hu) value was calculated for which the data was obtained from five various points on the proximal femur and acetabulum. Beta-2 microglobulin (B2M) blood test was performed to confirm amyloid bone disease.

Results. The authors did not observe statistically significant differences for arthroplasty outcomes in patients of group II and III. Patients receiving long-term hemodialysis demonstrated significantly lower parameters of Harris score and Barthel’s index of social adaptation after hip replacement as compared to groups II and III: patients of group I demonstrated outcomes improvement at 19.55%, in group II — at 13.03%, in group III — at 10.15% as compared to preoperative status. Decrease of 1.25-dihydroxyvitamin D below 20,0 mcg results in resorption of cancellous bone in proximal femur and acetabulum along with myopathy of gluteus muscles. Sharp increase of parathyroid hormone level (over 600 pcg/ml) was accompanied by inhibition of osteoblasts proliferation and differentiation resulting in substantial impairment of mineralization.

Conclusion. According to the algorithm suggested by the authors the key parameters that need to be evaluated in preoperative period are parathyroid hormone (PTH) and 1.25-dihydroxyvitamin D. Five-fold increase of PTH (>600 pcg/ml) demands parathyroidectomy as the first stage of treatment to decrease risk of early aseptic loosening of hip prosthesis and development of periprosthetic fracture.

Multivessel Coronary Revascularization Strategies in Patients with Chronic Kidney Disease: A Meta-Analysis

Background: Early revascularization can lead to better prognosis in multivessel coronary artery disease (CAD) patients with chronic kidney disease (CKD). However, whether coronary artery bypass grafting (CABG) or percutaneous coronary intervention (PCI) is better remains unknown. Methods: We searched PubMed and the Cochrane Library database from inception until December 9, 2017, for articles that compare outcomes of CABG and PCI in multivessel CAD patients with CKD. We pooled the odds ratios with a fixed-effects model when I2 < 50% or a random-effects model when I2 > 75% and conducted heterogeneity and quality assessments as well as publication bias analyses. Results: A total of 17 studies with 62,343 patients were included. Compared with CABG, the pooled analysis showed that PCI had a lower risk of short-term all-cause death (OR, 0.56; 95% CI, 0.37–0.84) and cerebrovascular accidents (OR, 0.65; 95% CI, 0.53–0.79) but a higher risk of cardiac death (OR, 1.29; 95% CI, 1.21–1.37), myocardial infarction (MI) (OR, 1.73; 95% CI, 1.35–2.21), and repeat revascularization (RR) (OR, 3.9; 95% CI, 2.99–5.09). There was no significant difference in the risk of long-term all-cause death (OR, 1.08; 95% CI, 0.95–1.23) and major adverse cardiac and cerebrovascular events (MACCE) (OR, 1.58; 95% CI, 0.99–2.52) between the PCI and CABG groups. A subgroup analysis restricted to patients treated with dialysis or with PCI-drug-eluting stent yielded similar results. Conclusions: PCI for patients with CKD and multivessel disease (multivessel CAD) had advantages over CABG with regard to short-term all-cause death and cerebrovascular accidents, but disadvantages regarding the risk of myocardial death, MI, and RR; there was no significant difference in the risk of long-term all-cause death and MACCE. Large randomized controlled trials are needed to confirm our findings.

Increasing fetal ovine number per gestation alters fetal plasma clinical chemistry values

Intrauterine growth restriction (IUGR) is interconnected with developmental programming of lifelong pathophysiology. IUGR is seen in human multifetal pregnancies, with stepwise rises in fetal numbers interfering with placental nutrient delivery. It remains unknown whether fetal blood analyses would reflect fetal nutrition, liver, and excretory function in the last trimester of human or ovine IUGR. In an ovine model, we hypothesized that fetal plasma biochemical values would reflect progressive placental, fetal liver, and fetal kidney dysfunction as the number of fetuses per gestation rose. To determine fetal plasma biochemical values in singleton, twin, triplet, and quadruplet/quintuplet ovine gestation, we investigated morphometric measures and comprehensive metabolic panels with nutritional measures, liver enzymes, and placental and fetal kidney excretory measures at gestational day (GD) 130 (90% gestation). As anticipated, placental dysfunction was supported by a stepwise fall in fetal weight, fetal plasma glucose, and triglyceride levels as fetal number per ewe rose. Fetal glucose and triglycerides were directly related to fetal weight. Plasma creatinine, reflecting fetal renal excretory function, and plasma cholesterol, reflecting placental excretory function, were inversely correlated with fetal weight. Progressive biochemical disturbances and growth restriction accompanied the rise in fetal number. Understanding the compensatory and adaptive responses of growth‐restricted fetuses at the biochemical level may help explain how metabolic pathways in growth restriction can be predetermined at birth. This physiological understanding is important for clinical care and generating interventional strategies to prevent altered developmental programming in multifetal gestation.

Coronary Artery Bypass Grafting vs. Drug-Eluting Stent Implantation for Multivessel Disease in Patients with Chronic Kidney Disease

BACKGROUND AND OBJECTIVES

There is currently a limited amount of data that demonstrate the optimal revascularization strategy for chronic kidney disease (CKD) patients with multivessel coronary artery disease (CAD). We compared the long-term outcomes of percutaneous coronary intervention (PCI) with drug-eluting stents (DES) versus coronary artery bypass graft surgery (CABG) for multivessel CAD in patients with CKD.

SUBJECTS AND METHODS

We analyzed 2108 CKD patients (estimated glomerular filtration rate <60 mL/min/1.73 m²) with multivessel CAD that were treated with PCI with DES (n=1165) or CABG (n=943). The primary outcome was a composite of all causes of mortality, myocardial infarction, or stroke. The mean age was 66.9±9.1 years.

RESULTS

Median follow-up duration was 41.4 (interquartile range 12.1-75.5) months. The primary outcome occurred in 307 (26.4%) patients in the PCI group compared with 304 (32.2%) patients in the CABG group (adjusted hazard ratio [HR], 0.941; 95% confidence interval [CI], 0.79-1.12; p=0.493). The two groups exhibited similar rates of all-cause mortality (adjusted HR, 0.91; 95% CI, 0.77-1.09; p=0.295), myocardial infarction (adjusted HR, 1.86; 95% CI, 0.85-4.07; p=0.120) and stroke (3.2% vs. 4.8%; HR, 0.93; 95% CI, 0.57-1.61; p=0.758). However, PCI was associated with significantly increased rates of repeat revascularization (adjusted HR, 4.72; 95% CI, 3.20-6.96; p<0.001).

CONCLUSION

Among patients with CKD and multivessel CAD, PCI with DES when compared with CABG resulted in similar rates of composite outcome of mortality from any cause, MI, or stroke; however, a higher risk of repeat revascularization was observed.

Incidence, predictors and outcomes of hematoma after ICD implantation: An analysis of a nationwide database of 85,276 patients

BACKGROUND

Pocket hematoma is one of the most common complications following cardiac device implantation. This study examined the impact of this complication on in-hospital outcomes following Implantable Cardioverter Defibrillator (ICD) implantation.

METHODS

Data from Nationwide Inpatient Sample (NIS) 2010 was queried to identify all primary implantations of ICDs and Cardiac Resynchronization Therapy Defibrillators (CRT-D) during the year 2010 using ICD-9 codes. We then identified the patients who experienced a procedure related hematoma during the hospital stay. We compared the outcomes of the patients with and without a hematoma complication. All analyses were performed using SPSS 20 complex samples using appropriate weights to adjust for the complex sampling design of the national database.

RESULTS

Out of a total of 85,276 primary ICD implantations in the year 2010, 2233 (2.6% of the implantations) were complicated by a hematoma. Increased age (p < 0.001), and comorbidities such as congestive heart failure (odds ratio (OR) - 1.86, p < 0.001), coagulopathy (OR - 2.3, p < 0.001) and renal failure (OR - 1.52, p < 0.001) were associated with an increased risk of pocket hematoma formation. Patients who developed a hematoma had a longer hospitalization (9.1 days versus 5.5 days, p < 0.001) and higher in-hospital costs ($56,545 versus $47,015, p < 0.001) compared to patients who did not have a hematoma. Overall mortality associated with ICD implantation was low (0.6%), and hematoma formation did not adversely affect mortality (0.6% versus 0.4%, p = 0.63).

CONCLUSION

Hematoma occurs infrequently after ICD implantation, however, it adversely impacts the cost of procedure and length of stay.

The Genetic Determinants of Renal Impairment Following Cardiac Surgery

Cardiac surgery is frequently performed, and acute renal dysfunction is a common adverse event following this procedure. Cardiac surgery-related renal injury independently predicts longer hospital stays and greater rates of morbidity and mortality. Although much work has been completed toward better understanding of this phenomenon, the state of knowledge concerning surgery-related renal injury remains limited. Currently, there is no effective paradigm to identify patients who are at risk for this condition; the specific mechanisms of renal injury during surgery are incompletely understood; and few therapies exist to prevent or treat this phenomenon. To better understand this common clinical problem, recent research has focused on the importance of genetic variability within the physiological and patho-physiological systems that underlie renal dysfunction following cardiac surgery. Emphasizing the importance of using genetics to elucidate molecular mechanisms of this disease, this article reviews the current literature on genetic polymorphisms and post cardiac surgery-related renal dysfunction.

Perioperative outcomes of coronary artery bypass graft in renal transplant recipients in the United States: results from the Nationwide Inpatient Sample

BACKGROUND

Cardiovascular disease is the leading cause of morbidity and mortality in patients with chronic kidney disease (CKD). In fact, death from cardiovascular disease is the number one cause of graft loss in kidney transplant (KTx) patients. Compared to patients on dialysis, CKD patients with KTx have increased quality and length of life. It is not known, however, whether outcomes of coronary artery bypass graft (CABG) surgery differ between CKD patients with KTx or on dialysis.

METHODS

This was a retrospective cohort study comparing CKD patients with KTx or on dialysis undergoing CABG surgery included in the Nationwide Inpatient Sample from 2002 to 2011. Logistic and linear regression models were used to estimate the adjusted associations of KTx on all-cause in-hospital mortality, length of stay, cost of hospitalization, and rate of complications in CABG surgery.

RESULTS

CKD patients with KTx had decreased all-cause in-hospital mortality (2.68% vs 5.86%, odds ratio (OR)=0.56, 95% confidence interval (CI)=0.32 to 0.99, P=.046), length of stay (β=-2.96, 95% CI=-3.67 to -2.46, P<.001), and total hospital charges (difference=-$38 884, 95% CI=-$48 173 to -29 596, P<.001). They also had decreased rate of a number of perioperative complications.

CONCLUSIONS

CKD patient with KTx have better perioperative outcomes in CABG surgery compared to patients on dialysis.

Kidney Function Does Not Modify the Favorable Quality of Life Changes Associated With Revascularization for Coronary Artery Disease: Cohort Study

Background

Although patients with kidney disease have potential to benefit from revascularization, they are also at higher risk of complications, which may affect quality of life.

Methods and Results

We studied a cohort of 8198 adults who underwent coronary angiography in Alberta, between 2004 and 2008, and completed health‐related quality‐of‐life (HR‐QOL) surveys. Changes in HR‐QOL measures were most favorable among patients who received coronary artery bypass graft (CABG), but did not significantly differ by kidney function within groups of patients who received CABG, percutaneous coronary intervention (PCI), or medical therapy (P value for interaction between estimated glomerular filtration rate [eGFR] and revascularization status >0.10 for all outcomes). Among those who received CABG, the adjusted mean EuroQol 5 dimensions (EQ‐5D) utility score for those with eGFR >90 mL/min per 1.73 m² increased by 0.11 (95% CI, 0.09–0.14) and for those with eGFR <30 mL/min per 1.73m² by 0.13 (95% CI, 0.05–0.21). The adjusted mean EQ‐5D utility score also increased similarly at all levels of eGFR for those who received PCI and for those who received medical management. Mean changes in Seattle Angina Questionnaire (SAQ) scores were also similar across all levels of eGFR within each treatment group for the quality of life, angina frequency, angina stability, physical limitations, and treatment satisfaction domains of the SAQ. Among those who received CABG, the adjusted mean SAQ quality of life score for those with eGFR >90 mL/min per 1.73m² increased by 22.1 (95% CI, 18.5–25.7) and for those with eGFR <30 mL/min per 1.73m² by 14.0 (95% CI, 2.31–25.63).

Conclusions

Changes in HR‐QOL do not vary by kidney function among patients selected for CABG, PCI, or medical management of coronary disease.

Duration of Postoperative Atrial Fibrillation After Cardiac Surgery Is Associated With Worsened Long-Term Survival

BACKGROUND

Studies of the effects of postoperative atrial fibrillation (poAF) on long-term survival are conflicting, likely because of comorbidities that occur with poAF and the patient populations studied. Furthermore, the effects of poAF duration on long-term survival are poorly understood.

METHODS

We utilized a prospectively collected database on outcomes of cardiac surgery at a large tertiary care institution between August 2001 and December 2010 with survival follow-up through June 2015 to analyze long-term survival of patients with poAF. In addition, we identified patient- and procedure-related variables associated with poAF, and estimated overall comorbidity burden using the Elixhauser comorbidity index. Survival was compared between patients with poAF (n = 513) and a propensity score matched control cohort, both for all patients and separately for subgroups of patients with poAF lasting less than 2 days (n = 218) and patients with prolonged poAF (n = 265).

RESULTS

Patients with poAF were older and had a higher burden of comorbidities. Survival was significantly worse for patients with poAF than for the matched control group (hazard ratio 1.43, 95% confidence interval: 1.11 to 1.86). That was driven by decreased survival among patients with prolonged poAF (hazard ratio 1.97, 95% confidence interval: 1.37 to 2.80), whereas survival of patients with poAF for less than 2 days was not significantly different from that of matched controls (hazard ratio 0.91, 95% confidence interval: 0.60 to 1.39).

CONCLUSIONS

After close matching based on comorbidity burden, prolonged poAF is still associated with decreased survival. Therefore, vigilance is warranted in monitoring and treating patients with prolonged poAF after cardiac surgery.

Postoperative acute kidney injury defined by RIFLE criteria predicts early health outcome and long-term survival in patients undergoing redo coronary artery bypass graft surgery

Objective

To investigate the impact of postoperative acute kidney injury (AKI) on early health outcome and on long-term survival in patients undergoing redo coronary artery bypass grafting (CABG).

Methods

We performed a Cox analysis with 398 consecutive patients undergoing redo CABG over a median follow-up of 7 years (interquartile range, 4-12.2 years). Renal function was assessed using baseline and peak postoperative levels of serum creatinine. AKI was defined according to the risk, injury, failure, loss, and end-stage (RIFLE) criteria. Health outcome measures included the rate of in-hospital AKI and all-cause 30-day and long-term mortality, using data from the United Kingdom's Office of National Statistics. Propensity score matching, as well as logistic regression analyses, were used. The impact of postoperative AKI at different time points was related to survival.

Results

In patients with redo CABG, the occurrence of postoperative AKI was associated with in-hospital mortality (odds ratio [OR], 3.74; 95% confidence interval [CI], −1.3 to 10.5; P < .01], high Euroscore (OR, 1.27; 95% CI, 1.07-1.52; P < .01), use of IABP (OR, 6.9; 95% CI, 2.24-20.3; P < .01), and reduced long-term survival (hazard ratio [HR], 2.42; 95% CI, 1.63-3.6; P = .01). Overall survival at 5 and 10 years was lower in AKI patients with AKI compared with those without AKI (64% vs 85% at 5 years; 51% vs 68% at 10 years). On 1:1 propensity score matching analysis, postoperative AKI was independently associated with reduced long term survival (HR, 2.8; 95% CI, 1.15-6.7).

Conclusions

In patients undergoing redo CABG, the occurrence of postoperative AKI is associated with increased 30-day mortality and major complications and with reduced long-term survival.

Complications and Mortality in Chronic Renal Failure Patients Undergoing Total Joint Arthroplasty: A Comparison Between Dialysis and Renal Transplant Patients

BACKGROUND

In total joint arthroplasty (TJA) literature, there is a paucity of large cohort studies comparing chronic kidney disease (CKD) and end-stage renal disease (ESRD) vs non-CKD/ESRD patients. Thus, the purposes of this study were (1) to identify inhospital complications and mortality in CKD/ESRD and non-CKD/ESRD patients and (2) compare inhospital complications and mortality between dialysis and renal transplantation patients undergoing TJA.

METHODS

We queried the Nationwide Inpatient Sample database for patients with and without diagnosis of CKD/ESRD and those with a renal transplant or on dialysis undergoing primary or revision total knee or hip arthroplasty from 2007 to 2011. Patient comorbidities were identified using the Elixhauser comorbidity index. International Classification of Diseases, Ninth Revision, codes were used to identify postoperative surgical site infections (SSIs), wound complications, deep vein thrombosis, and transfusions.

RESULTS

Chronic kidney disease/ESRD was associated with greater risk of SSIs (odds ratio [OR], 1.4; P<.001), wound complications (OR, 1.1; P=.01), transfusions (OR, 1.6; P<.001), deep vein thrombosis (OR, 1.4; P=.03), and mortality (OR, 2.1; P<.001) than non-CKD/ESRD patients. Dialysis patients had higher rates of SSI, wound complications, transfusions, and mortality compared to renal transplant patients.

CONCLUSION

Chronic kidney disease/ESRD patients had a greater risk of SSIs and wound complications compared to those without renal disease, and the risk of these complications was even greater in CKD/ESRD patients receiving dialysis. These findings emphasize the importance of counseling CKD patients about higher potential complications after TJA, and dialysis patients may be encouraged to undergo renal transplantation before TJA.

Mode of Coronary Revascularization and Short term Clinical Outcomes in Patients with Chronic Kidney Disease

Background and Objective: Percutaneous coronary intervention (PCI) and coronary artery bypass graft (CABG) surgery are two alternative methods for coronary revascularization, but it remains controversial as which one is associated with lower risks of worse clinical outcomes for chronic kidney disease (CKD) patients. We determined the mode of coronary revascularization (PCI vs. CABG) which is associated with lower risk of mortality and morbidity in CKD patients.

Methods: In this cross sectional study, 159 patients with CKD were enrolled from single center of coronary revascularization at Aga Khan University Hospital Karachi between January 2012 and August 2013. All patients with CKD underwent PCI or CABG. The primary outcome was in-hospital composite of death, myocardial infarction (MI), or stroke. We evaluated which mode of coronary revascularization was associated with reduced risks of clinical outcomes.

Results: Out of 159 patients with CKD, 85 (53.5%) received PCI and 74 (46.5%) received CABG. The primary finding of this study is that more patients with moderate to severe CKD underwent PCI and more patients with mild to moderate CKD underwent CABG. In both these categories, no difference was observed in clinical outcomes. There are few factors like age, ST- elevation myocardial infarction (STEMI), non-ST elevation myocardial infarction (NSTEMI) and number of coronary artery disease predicted PCI as treatment strategy in patients with moderate to severe CKD.

Conclusion: Patients with moderate to severe CKD have similar rates of short term clinical outcomes whether they underwent PCI or CABG. Therefore, PCI can be acceptable and less invasive treatment option alternative to CABG, particularly in patients with moderate to severe CKD.

Evaluation of the Society of Thoracic Surgeons score system for isolated coronary bypass graft surgery in a Brazilian population

Objective

Report the experience with the Society of Thoracic Surgeons scoring system in a Brazilian population submitted to isolated coronary artery bypass graft surgery.

Methods

Data were collected from January-2010 to December-2011, and analyzed to determine the performance of the Society of Thoracic Surgeons scoring system on the determination of postoperative mortality and morbidity, using the method of the receiver operating characteristic curve as well as the Hosmer-Lemeshow and the Chi-square goodness of fit tests. From the 1083 cardiac surgeries performed during the study period 659 represented coronary artery bypass graft procedures which are included in the present analysis. Mean age was 61.4 years and 77% were men.

Results

Goodness of fit tests have shown good calibration indexes both for mortality (X²=6.78, P=0.56) and general morbidity (X²=6.69, P=0.57). Analysis of area under the ROC-curve (AUC) demonstrated a good performance to detect the risk of death (AUC 0.76; P<0.001), renal failure (AUC 0.79; P<0.001), prolonged ventilation (AUC 0.80; P<0.001), reoperation (AUC 0.76; P<0.001) and major morbidity (AUC 0.75; P<0.001) which represents the combination of the assessed postoperative complications. STS scoring system did not present comparable results for short term hospital stay, prolonged length of hospital stay and could not be properly tested for stroke and wound infection.

Conclusion

Society of Thoracic Surgeons scoring system presented a good calibration and discrimination in our population to predict postoperative mortality and the majority of the harmful events following coronary artery bypass graft surgery. Analysis of larger samples might be needed to further validate the use of the score system in Brazilian populations.

Cardiovascular risk assessment in kidney transplantation

Cardiovascular disease (CVD) remains the most common cause of death after kidney transplantation worldwide, with the highest event rate in the early postoperative period. In an attempt to address this issue, screening for CVD prior to transplant is common, but the clinical utility of screening asymptomatic transplant candidates remains unclear. A large degree of variation exists among both transplant center practice patterns and clinical practice guidelines regarding who should be screened, and opinions are based on mixed observational data with great potential for bias. In this review, we discuss the potential risks, benefits, and evidence for screening for CVD in kidney transplant candidates, and also the next steps to better evaluate and treat asymptomatic kidney transplant candidates.

Does mild renal failure affect coronary flow reserve after coronary artery bypass graft surgery?

INTRODUCTION

There are only a limited number of studies on the link between mild renal failure and coronary artery disease. The purpose of this study is to investigate the effects of mild renal failure on the distal vascular bed by measuring the coronary flow reserve (CFR) in transthoracic echocardiography after coronary artery bypass grafting (CABG).

METHODS

The study included 52 consecutive patients (12 women and 40 men) who had undergone uncomplicated CABG. The patients were divided into 2 groups. Group 1 included patients with a preoperative glomerular filtration rate (GFR) of 60-90 (mild renal failure), and group 2 included those with a GFR >90. The CFR measurements were carried out through a second harmonic transthoracic Doppler echocardiography.

RESULTS

The mean age was 60.08 ± 1.56 years in group 1 and 60.33 ± 1.19 in group 2. The mean preoperative CFR was 1.79 ± 0.06 in group 1 and 2.05 ± 0.09 in group 2. The mean postoperative CFR was 2.09 ± 0.08 in group 1 and 2.37 ± 0.06 in group 2. There was a statistically significant difference between the 2 groups as to preoperative creatinine clearance, preoperative estimated GFR, postoperative day 7 creatinine clearance, postoperative month 6 creatinine clearance, postoperative day 7 estimated GFR, postoperative month 6 estimated GFR, preoperative CFR, and postoperative CFR (P < .05). CFR was found to be unaffected by the choice of on-pump or off-pump technique (P = .907). After bypass surgery, there was a significant increase in the mean postoperative CFR, when compared with the mean preoperative CFR (P = .001).

CONCLUSION

In our study, we detected a decrease in CFR in patients with mild renal failure. We believe that in patients undergoing CABG for coronary artery disease, mild renal failure can produce adverse effects due to deterioration of the microvascular bed.

Acute kidney injury after cardiac surgery according to Risk/Injury/Failure/Loss/End-stage, Acute Kidney Injury Network, and Kidney Disease: Improving Global Outcomes classifications

PURPOSE

The epidemiology of acute kidney injury (AKI) after cardiac surgery depends on the definition used. Our aims were to evaluate the Risk/Injury/Failure/Loss/End-stage (RIFLE) criteria, the AKI Network (AKIN) classification, and the Kidney Disease: Improving Global Outcomes (KDIGO) classification for AKI post-cardiac surgery and to compare the outcome of patients on renal replacement therapy (RRT) with historical data.

METHODS

Retrospective analysis of 1881 adults who had cardiac surgery between May 2006 and April 2008 and determination of the maximum AKI stage according to the AKIN, RIFLE, and KDIGO classifications.

RESULTS

The incidence of AKI using the AKIN and RIFLE criteria was 25.9% and 24.9%, respectively, but individual patients were classified differently. The area under the receiver operating characteristic curve for hospital mortality was significantly higher using the AKIN compared with the RIFLE criteria (0.86 vs 0.78, P = .0009). Incidence and outcome of AKI according to the AKIN and KDIGO classification were identical. The percentage of patients who received RRT was 6.2% compared with 2.7% in 1989 to 1990. The associated hospital mortality fell from 82.9% in 1989 to 1990 to 15.6% in 2006 to 2008.

CONCLUSIONS

The AKIN classification correlated better with mortality than did the RIFLE criteria. Mortality of patients needing RRT after cardiac surgery has improved significantly during the last 20 years.

Association between chronic kidney disease and blood transfusions for knee and hip arthroplasty surgery

The study aim is to assess associations between chronic kidney disease (CKD) and blood transfusions during hospitalization for joint arthroplasty. Patients with Stage IV-V CKD who underwent elective total knee or hip arthroplasty from 2007 to 2010 were matched 2:1 with age, gender, and surgery type controls without kidney disease. Multivariable analyses for transfusion risk with preoperative hemoglobin, body mass index, cardiovascular disease, and surgical complexity as explanatory variables were performed. Ninety CKD patients were identified and had lower preoperative hemoglobin, higher incidence of cardiovascular disease and blood transfusions. CKD was independently associated with increased odds of transfusions (2.88, 95% confidence interval 1.33-6.23, P=0.007). Preoperative optimization of CKD patients should be considered to reduce transfusion rates.

Acute kidney injury after cardiovascular surgery: an overview

Acute kidney injury is a complication of open-heart surgery that carries a poor prognosis. Studies have shown that postoperative renal function deterioration in cardiovascular surgery patients increases in-hospital mortality and adversely affects long-term survival. Identifying individuals at risk for developing AKI and aggressive early intervention is extremely important to optimize outcomes. This paper provides an overview of the etiology, prognostic markers, risk factors, and prevention of AKI and treatments that may favorably affect outcomes.

Frequency of and risk factors for complications after liver radiofrequency ablation under CT fluoroscopic guidance in 1500 sessions: single-center experience

OBJECTIVE

The purpose of this article is to retrospectively evaluate the frequency of and risk factors for complications after liver radiofrequency ablation (RFA).

MATERIALS AND METHODS

This was a retrospective study of 656 patients (with 1755 liver tumors) who underwent 1500 CT fluoroscopy-guided liver RFA sessions. Of those patients, 501 had primary liver tumor and 155 had liver metastases. Mortality and treatment-related complications were documented. Complications were evaluated according to the Common Terminology Criteria for Adverse Events (version 4.0). Major complications were defined as grade 3 or higher adverse events. Factors affecting frequent complications with a frequency of 1% or more were detected using multivariate analysis.

RESULTS

Two deaths (0.1% [2/1500]) occurred. One patient died of liver failure subsequent to hemorrhage, and the other died of liver failure. The major complication rate was 2.8% (42/1500). The most frequent major complication was hemorrhage (1.1% [16/1500]). The absence of arterial embolization before RFA (p < 0.01), low hemoglobin level (p < 0.04), and elevated serum creatinine level (p < 0.04) were identified as significant risk factors for major hemorrhage. The minor complication rate was 17.1% (257/1500). Pneumothorax (7.7% [116/1500]) was the most frequent minor complication, followed by hemorrhage (7.0% [105/1500]). A transthoracic approach (p < 0.01) and subphrenic tumor location (p < 0.01) were significant risk factors for pneumothorax, and the use of a cluster needle (p < 0.02) and multiple tumors (p < 0.01) were significant risk factors for minor hemorrhage.

CONCLUSION

CT fluoroscopy-guided RFA is a safe procedure with an acceptably low rate of major complications for liver tumor treatment. Factors identified in this study will help to stratify high-risk patients.

Impact of increasing degrees of renal impairment on outcomes of coronary artery bypass grafting: the off-pump advantage

OBJECTIVES

Increasing degrees of renal impairment are associated with higher rates of morbimortality after coronary artery bypass grafting (CABG). This incremental risk has not been well studied in off-pump procedures (OPCAB). We assessed its impact on OPCAB and on-pump CABG (ONCAB).

METHODS

A total of 1769 patients undergoing primary CABG (January 1995 through June 2011) had complete data on glomerular filtration rate (eGFR). 930 patients had Stage 2 renal insufficiency, 330 Stage 3, 27 Stage 4 and 465 normal renal function (Stage 1). Seventeen patients with end-stage disease (Stage 5) were excluded. The OPCAB technique was selectively used in 350 high-risk patients. Preoperative variables and postoperative outcomes were compared among eGFR subgroups and between matched and unmatched OPCAB vs ONCAB groups.

RESULTS

Stages 3-4 patients were older (P < 0.0001), with higher prevalence of diabetes (36.8, 35.0, 39.7 and 74.1%, P < 0.01, 1-4 eGFR groups) peripheral arteriopathy (6.0, 9.0, 15.8 and 29.6%, P < 0.0001) and lower left ventricular ejection fraction (LVEF) (GFR-LVEF correlation: Pearson: 0.12, P < 0.0001). On-pump GFR groups had increasingly higher in-hospital mortality (1.0, 1.2, 3.5 and 15.4%, P < 0.0001), but no differences were observed in OPCAB (5.5, 4.8, 5.4 and 7.1%, P = 0.97). Similar trends on in-hospital morbidity were observed in ONCAB vs OPCAB groups: low cardiac output (P < 0.01), pneumonia (P < 0.01) and stroke (P < 0.05). GFR only predicted mortality in ONCAB patients (odds ratio (OR): 0.96, 95% CI: 0.94-0.98; P < 0.01). Patients with higher eGFR stages had statistically more reduced long-term survival, and this pattern was similar in the three treatment groups, also including the OPCAB group, who had the lowest survival in patients with eGFR stage 4.

CONCLUSIONS

Patients with low GFR (Stages 3-4) undergoing ONCAB were at increased risk of early morbimortality. In contrast, there were no significant differences in operative morbimortality among eGFR groups in OPCAB patients. This 'off-pump advantage' on early outcomes was not observed at the long-term follow-up.

Predictors of Prolonged Stay in the Intensive Care Unit following Cardiac Surgery

The prediction of intensive care unit length of stay (ICU-LOS) could contribute to more efficient ICU resources' allocation and better planning of care among cardiac surgery patients. The aim of this study was to identify the preoperative and intraoperative predictors for prolonged cardiac surgery ICU-LOS. An observational cohort study was conducted among 150 consecutive patients, who were admitted to the cardiac surgery ICU of a tertiary hospital of Athens, Greece from September 2010 to January 2011. Multivariate regression analysis revealed that patients with increased creatinine levels preoperatively (odds ratio (OR) 3.0, P = 0.049), history of atrial fibrillation (AF) (OR 6.3, P = 0.012) and high EuroSCORE values (OR 2.6, P = 0.017) had a significant greater probability to stay in the ICU for more than 2 days. In addition, intraoperative hyperglycemia (OR 3.0, P = 0.004) was strongly associated with longer ICU-LOS. In conclusion, the high perioperative risk, the history of AF and renal dysfunction, and the intraoperative hyperglycemia are significant predictors of prolonged ICU stay. The early identification of patients at risk could allow the efficient ICU resources' allocation and the reduction of healthcare costs. This would contribute to nursing care planning depending on the availability of healthcare personnel and ICU bed capacity.

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.

Should eGFR and albuminuria be added to the Framingham risk score? Chronic kidney disease and cardiovascular disease risk prediction

Presence of chronic kidney disease (CKD) defined as decreased glomerular filtration rate (GFR) and/or increased urine albumin excretion is associated with heightened risk of cardiovascular disease (CVD) and all-cause as well as CVD mortality. Although CKD is strongly linked with CVD, it remains undetermined whether this strong association is simply due to shared CVD risk factors or unique traits consequential to CKD. The probability of future CVD events can be estimated with reasonable accuracy using the Framingham equation which was derived from the Framingham study, a community-based cohort of 5,209 white adults aged 30-62 years who were first examined in 1948. Efforts to capture excess CVD risk associated with CKD have been evaluated by adding estimated GFR, cystatin C, serum creatinine and measures of urinary albumin excretion to the Framingham equation which is based on traditional cardiovascular risk factors. Although decreased GFR and increased urine albumin excretion are consistently associated with cardiovascular outcomes, the addition of these factors to the Framingham equation has not been shown to substantially improve overall CVD risk prediction in populations not enriched with CKD. Moreover, the Framingham equation itself underpredicts cardiovascular events among adults with stage 3 and 4 CKD without clinical CVD. Given the poor performance of the Framingham equation in adults with CKD, future studies should explore risk equations which include traditional CVD risk factors and the unique comorbidities associated with CKD for prediction of cardiovascular events in adults with CKD.

Impact of preoperative renal dysfunction in patients undergoing off-pump versus on-pump coronary artery bypass

BACKGROUND

The impact of the degree of renal dysfunction (RD) in patients undergoing coronary artery bypass grafting (CABG) ranging from normal to dialysis-dependence is not well defined.

METHODS

A retrospective review of 14,199 patients undergoing isolated, primary CABG from January 1996 to May 2009 at Emory Healthcare was performed. The estimated glomerular filtration rate (eGFR) was estimated by the Modification of Diet in Renal Disease formula: mild RD (eGFR 60 to 90 mL/min/1.73 m2), moderate RD (eGFR 30 to 59), severe RD (eGFR<30). A propensity scoring was used to balance the groups with 46 preoperative covariates. Multivariable logistic and Cox regression methods were used to determine the independent association of eGFR with mortality. Adjusted odds ratios were calculated for outcomes using the normal eGFR group as the reference. Kaplan-Meier curves were created to estimate long-term survival.

RESULTS

A total of 8,086 patients (57.0%) underwent off-pump coronary artery bypass (OPCAB) while 6,113 (43.0%) underwent on-pump CAB. Preoperative RD was common: Normal eGFR (n=3,503/14,199 [24.7%]); mild RD (7,236/14199 [51.0%]); moderate RD (2,860/14,199 [20.1%]); severe RD (283/14,199 [2.0%]); and preoperative dialysis (317/14,199 [2.2%]). Moderate to severe RD or preoperative dialysis was associated with worse adjusted in-hospital mortality: mild RD (odds ratio [OR] 1.42; 95% confidence interval [CI] 0.93 to 2.16; p=not significant); moderate RD (OR 3.55; 95% CI 2.32 to 5.43; p<0.05]; severe RD (OR 8.84; 95% CI 4.92 to 15.9; p<0.05); and dialysis-dependent (OR 9.64; 95% CI 5.45 to 17.0; p<0.05). Adjusted long-term survival was worse across levels of RD. The OPCAB patients with moderate to severe RD had worse long-term survival than on-pump CAB patients; however, the surgery types were similar among normal, mild, and dialysis patients.

CONCLUSIONS

Preoperative RD is common in the CABG population and is associated with diminished long-term survival. Improved early outcomes in patients with RD undergoing OPCAB diminished with worsening RD.

Postoperative outcomes in patients with chronic renal failure undergoing coronary artery bypass grafting in madani heart center: 2000-2010

INTRODUCTION

Renal failure predisposes patients to adverse outcome after coronary artery bypass grafting (CABG). Renal dysfunction is a predictor of increased morbidity and mortality after CABG, whether it is dialysis-dependent or not.

METHODS

In a retrospective study from April 2000 to December 2010, seventy-six patients (60 male and 16 female with the mean age of 58.57±7.93 years) with different categories of chronic renal failure undergoing CABG in Shahid Madani Hospital, were studied. The cardiac disease leading to the operation was coronary artery disease (CAD) in all patients. Patients demographic, surgical and laboratory data were gathered from hospital records. Data were then analyzed.

RESULTS

Mean hospital stay was 10.16±7.16 days. The preoperative mortality rate was 10.5% (15% in non dialysis and 5.6% in dialysis dependant patients with no significant difference). Morbidity rate was 28.9% (respectively 30% and 27.8% in dialysis and non dialysis patients with no significant difference) including in-hospital myocardial infarction (MI) (10.5%), in-hospital stroke (2.6%), in-hospital bleeding (21.1%) and in-hospital infection, pneumonia, (5.3%). Mean creatinine and blood urea nitrogen (BUN) levels were significantly increased after surgery (p<0.001). Postoperative hemodialysis rate was 33.3%.

CONCLUSION

Chronic renal failure whether dialysis-dependant or not increases in-hospital mortality and morbidity in patients undergoing CABG. For CRF patients not on dialysis with a creatinine 2.5 gm/dL, there is a strong likelihood of postoperative dialysis.

Relation between renal dysfunction requiring renal replacement therapy and promoter polymorphism of the erythropoietin gene in cardiac surgery

Several genetic polymorphisms have been identified to play a role in the occurrence and progression of renal dysfunction after cardiac surgery with cardiopulmonary bypass (CPB). Recently, it was demonstrated that the T allele of SNP rs1617640 in the promoter of the erythropoetin (EPO) gene is significantly associated with proliferative diabetic retinopathy (PDR) and end-stage renal disease (ESRD) due to increased EPO expression. This disease risk-associated gene and its potential pathway mediating severe microvascular complications in T-allele carriers could also play a role on renal dysfunction in patients who underwent cardiac surgery with CPB. We hypothesized that the patients' ability to produce increased EPO concentrations will affect morbidity and mortality after CPB. We conducted a prospective single center study between April 2006 and May 2007. In 481 patients who underwent cardiac surgery with CPB we prospectively examined the SNP rs1617640 in the promoter of the EPO gene by DNA sequencing. The patients were grouped according to their genotype (GG, GT, and TT). The genotype distribution of SNP rs1617640 in the promoter of the EPO gene was 36% (TT), 49% (TG), and 15% (GG). There was no difference in age, body mass index, gender, CPB time, or length of stay in intensive care unit. The hospitalization was irrespective of the patients' genotypes. The baseline creatinine in the TT group was 0.2 points higher than in the other groups; however this was without statistical significance in the multivariate analysis. No significant difference was shown in Euroscore, the Simplified Acute Physiology Score II, the Acute Physiology and Chronic Health Evaluation Score II, Acute Renal Failure Score, or the Risk, Injury, Failure, Loss of Kidney Function Score. The mortality was equal across the genotypes. However, an association between the TT genotype and acute renal replacement therapy (P=0.03), intra-aortic balloon pump usage (P=0.02), and serum creatine phosphokinase-MB increase (P=0.03) were observed after cardiac surgery. Our analysis suggests that the risk allele (T) of rs1617640 plays a role in the development of renal dysfunction after cardiac surgery with CPB. Patients with the TT risk allele required more frequent acute renal replacement therapy. Since our result is close to the border of significance, this hypothesis should be investigated in larger prospective studies with long-term follow-up to emphasize this polymorphism as a potential risk factor.