A prospective randomized study to evaluate the renoprotective action of beating heart coronary surgery in low risk patients.

OBJECTIVES: Cardiopulmonary bypass (CPB) is widely regarded as an important contributor to renal failure, a well recognized complication following coronary artery surgery (coronary artery bypass grafting (CABG)). Anecdotally off-pump coronary surgery (OPCAB) is considered renoprotective. We examine the extent of renal glomerular and tubular injury in low-risk patients undergoing either OPCAB or on-pump coronary artery bypass (ONCAB). METHODS: Forty low-risk patients with normal preoperative cardiac and renal functions awaiting elective CABG were prospectively randomized into those undergoing OPCAB (n=20) and ONCAB (n=20). Glomerular and tubular injury were measured respectively by urinary excretion of microalbumin and retinol binding protein (RBP) indexed to creatinine (Cr). Daily measurements were taken from admission to postoperative day 5. Fluid balance, serum Cr and blood urea were also monitored. RESULTS: No mortality or renal complication were observed. Both groups had similar demographic makeup, Parsonnet score, functional status and extent of coronary revascularization (2.1+/-1.0 vs. 2.5+/-0.7 grafts; P=0.08). Serum Cr and blood urea remained normal in both groups throughout the study. A significant and similar rise in urinary RBP:Cr occurred in both groups peaking on day 1 (3183+/-2534 vs. 4035+/-4079; P=0.43) before reapproximating baseline levels. These trends were also observed with urinary microalbumin:Cr (5.05+/-2.66 vs. 6.77+/-5.76; P=0.22). Group B patients had a significantly more negative fluid balance on postoperative day 2 (-183+/-1118 vs. 637+/-847 ml; P=0.03). CONCLUSIONS: Although renal complication or serum markers of kidney dysfunction were absent, sensitive indicators revealed significant and similar injury to renal tubules and glomeruli following either OPCAB or ONCAB. These results suggest that avoidance of CPB does not offer additional renoprotection to patients at low risk of perioperative renal insult during CABG.     

Differences in pH management and pulsatile/nonpulsatile perfusion during cardiopulmonary bypass do not influence renal function.

The renal effects of pulsatile (pulse pressure 18.0 +/- 1.5 mm Hg [mean +/- SEM]) or nonpulsatile perfusion (mean pulse pressure 1.9 +/- 0.4 mm Hg) during either alpha-stat (mean PaCO2 41.2 +/- 0.9 mm Hg measured at 37 degrees C) or pH-stat (mean PaCO2 60.6 +/- 1.7 mm Hg measured at 37 degrees C) pH management of hypothermic cardiopulmonary bypass (CPB) were studied in 100 patients undergoing elective coronary artery bypass surgery. Mean urine output, fractional excretion of sodium and potassium, and renal failure index all increased during the study period; however, there was no difference among the four different CPB management groups. Mean postoperative creatinine and blood urea nitrogen values decreased compared with preoperative values, again without differences among treatment groups. Three patients developed acute renal insufficiency; of these, two had received nonpulsatile perfusion and pH-stat management, and the other had been managed with pulsatile perfusion and pH-stat management. These three patients all had undergone prolonged CPB and required at least two vasoactive drugs and the use of an intraaortic balloon pump to be weaned from CPB. In patients with normal preoperative renal function undergoing hypothermic CPB, neither the mode of perfusion, pulsatile or nonpulsatile, nor the method of pH management, pH-stat or alpha-stat, influences perioperative renal function.     

Dopamine therapy for patients at risk of renal dysfunction following cardiac surgery: science or fiction?

OBJECTIVES: We aimed to evaluate the renoprotective role of renal-dose dopamine on cardiac surgical patients at high risk of postoperative renal dysfunction. The latter included older patients or those with pre-existing renal disease, elevated preoperative serum creatinine (Cr), poor ventricular function, hypertension, diabetes mellitus and unstable angina requiring intravenous therapy. METHODS: Fifty patients undergoing cardiopulmonary bypass (CPB) who fulfilled the entry criteria were prospectively randomized into two groups: Group 1 received a 'renal-dose' (3 microg kg(-1) min(-1)) dopamine infusion starting at anaesthetic induction for 48 h whilst saline infusion acted as placebo in Group 2. The anaesthetic and CPB regimes were standardized. Urinary excretion of retinol binding protein (RBP) indexed to Cr, an accurate and sensitive marker of early renal tubular damage, was assessed daily for 6 days. Additional outcome measures included daily fluid balance, blood urea and serum Cr. Statistical comparisons were made using ANOVA and Mann-Whitney U-test. RESULTS: No significant difference was found between the groups in their age, gender, preoperative NYHA class, ejection fraction, baseline serum Cr and duration of CPB and aortic cross-clamping. Renal replacement therapy was not required in any instance. Both groups demonstrated a similar and significant rise in urinary RBP throughout the study period. Dopamine-treated patients achieved more negative average fluid balance than those on placebo (5 vs. 229 ml, P<0.05). CONCLUSIONS: Renal-dose dopamine therapy failed to offer additional renoprotection to patients considered at increased risk of renal dysfunction after CPB.     

Effect of off-pump and on-pump coronary artery bypass grafting on renal function

BACKGROUND: Coronary artery bypass grafting (CABG) with cardiopulmonary bypass (CPB) has the risk of renal dysfunction. The cause of renal dysfunction after CPB is multifactorial, such as nonpulsatile flow, renal hypoperfusion, hypothermia, and duration of CPB. This study compared off-pump technique with on-pump technique on renal function in patients who underwent CABG. METHODS: Sixty patients with normal preoperative renal functions undergoing CABG were randomly assigned to conventional revascularization with CPB (on-pump) or beating heart revascularization (off-pump). Renal functions were assessed up to 10 days postoperatively. RESULTS: Creatinine clearance was found to be significantly higher in the off-pump group than in the on-pump group (p<.05). The off-pump group had significantly less increase in creatinine levels when compared with the on-pump group (p<.05). The free water clearance values decreased similarly in both groups; however, the recovery was more prompt in the off-pump group (p<.05). No significant differences were found in the prevalence of postoperative hemodialysis. CONCLUSION: The off-pump technique may provide a positive contribution and sufficient protection on postoperative renal functions in patients undergoing CABG.     

Complete revascularization in coronary artery bypass grafting with and without cardiopulmonary bypass

BACKGROUND: The feasibility of complete revascularization on the beating heart without cardiopulmonary bypass (CPB) as compared with the standard operation with CPB in elective low-risk patients with multivessel disease has not been clearly demonstrated in a prospective trial. METHODS: Eighty selected low-risk patients were enrolled. In preoperative study with coronary angiography, the decision was made whether complete revascularization without CPB could be performed. Patients were randomly assigned to receive CABG either with (n = 40) or without CPB (n = 40). Randomization criteria were age, sex, and left ventricular ejection fraction. Completeness of revascularization as well as short- and mid-term clinical outcome in a 13.4 +/- 6.5 month follow-up period were monitored. RESULTS: Twenty-six of 40 (65%) patients undergoing CABG without CPB underwent complete revascularization. In 5 of these patients (12.5%) suitable vessels were discarded for technical reasons and 9 patients (22.5%) were switched to CABG with CPB owing to the deeply intramyocardial course of target vessels (n = 5) or to hemodynamic instability (n = 4). In the group of patients operated on with CPB, 34 of 40 patients (85%) received complete revascularization. In 6 patients (15%) suitable vessels were discarded for technical reasons. Mean number of bypass grafts was 3.1 +/- 0.8 with CPB and 2.6 +/- 0.5 without CPB (p = 0.043). Clinical outcome and hospital stay were comparable in both groups. No patient died during the study period. No myocardial infarction was observed. Three patients undergoing CABG without CPB underwent successful PTCA 3 months after surgery. CONCLUSIONS: CABG without the use of CPB is effective for complete revascularization in the majority of selected low-risk patients. Nevertheless, it has to be stated that the rate of incomplete revascularization in this early series of CABG without CPB is higher, and compromises the basic principle of complete revascularization.     

Off-pump versus on-pump coronary artery bypass surgery and postoperative renal dysfunction

Renal dysfunction is a serious complication after coronary bypass surgery with cardiopulmonary bypass (CABG). Because duration of cardiopulmonary bypass (CPB) is associated with renal outcome, it has been proposed that avoidance of CPB with off-pump coronary bypass (OPCAB) may reduce perioperative renal insult. We therefore tested the hypothesis that OPCAB is associated with less postoperative renal dysfunction compared with CABG surgery. With IRB approval, we gathered data for 690 primary elective coronary bypass patients (OPCAB, 55; CABG, 635). Perioperative change in creatinine clearance (DCrCl) was calculated by using preoperative (CrPre) and peak postoperative (CrPost) serum creatinine values, and the Cockroft-Gault equation (DCrCl = CrPreCl - CrPostCl). Univariate and linear multivariate tests were used in this retrospective analysis; P: < 0.05 was considered significant. Multivariate analysis did not identify OPCAB surgery as an independent predictor of DCrCl. However, previously reported associations of PreCrCl, age, and diabetes with DCrCl were confirmed. Power analysis demonstrated an 80% power to detect a 7.0 mL/min DCrCl difference between study groups. In this retrospective study, we could not confirm that OPCAB significantly reduces perioperative renal dysfunction compared with CABG surgery. Our findings suggest that reduction of renal risk alone should not be an indication for OPCAB over CABG surgery. Implications: Retrospective analysis did not identify any significant difference in perioperative change in creatinine clearance after coronary revascularization with cardiopulmonary bypass compared with off-pump coronary surgery.     

Evaluation of Cystatin C as a marker of renal injury following on-pump and off-pump coronary surgery.

OBJECTIVE: Cardiopulmonary bypass is regarded as an important contributor to renal injury, whereas off-pump surgery is considered less damaging. Cystatin C, a cystine protease inhibitor, is more sensitive and specific than creatinine in the assessment of renal function. We assessed the value of Cystatin C in quantifying clinical and subclinical renal injury following on-pump and off-pump cardiac surgery. METHODS: Sixty consecutive patients were recruited: 30 patients undergoing on-pump CABG and 30 patients undergoing off-pump CABG. Blood samples were collected pre-operatively and on days 1, 2 and 4 postoperatively to measure serum creatinine and serum Cystatin C. Urinary samples were collected concurrently to measure microalbumin and N-acetyl-beta-glucosaminidase, denoting changes in renal glomerular and tubular function respectively. RESULTS: The off-pump group were older (65+/-11 vs. 61+/-8 years; P=0.046), had a higher mean Parsonnet score (9.4+/-6.2 vs. 5.4+/-3.6, P<0.01) and received fewer grafts (2.4+/-0.9 vs. 3.1+/-0.7; P<0.01) compared to the on-pump group. The groups were otherwise matched with respect to preoperative renal function and left ventricular function. Patients undergoing on-pump CABG had greater increases in all four parameters of renal injury. Adjustment for preoperative differences increased the size and significance of the effect of off-pump vs. on-pump surgery (percent difference 13%; 95% CI 2-26 for creatinine, and 16%; 95% CI 4-29 for Cystatin C). Cystatin and creatinine were strongly correlated with each other. CONCLUSIONS: Avoidance of cardiopulmonary bypass may reduce renal injury particularly in higher risk patients. Cystatin C proved to be a simple and sensitive measure of overall renal function and can be used in the routine assessment of renoprotective strategies.     

Off-pump versus on-pump coronary artery bypass grafting: oxidative stress and renal function.

OBJECTIVES: Oxidative stress and renal dysfunction occur in patients undergoing coronary artery bypass grafting with cardiopulmonary bypass (on-pump CABG). Whether the same adverse effects also occur during off-pump CABG is the question in this study. METHODS: Forty patients, 27 men and 13 women, undergoing elective CABG were included; 20 patients underwent on-pump CABG and 20 patients underwent off-pump CABG. Renal and ischemia/reperfusion injury parameters were studied, as well as malondialdehyde as a parameter for oxidative stress. RESULTS: The renal function measured as the mean urinary creatinine excretion decreased significantly during surgery for the on-pump CABG group from 7.62+/-4.74 before surgery to 3.07+/-1.49 mmol/l after surgery, whereas no changes occurred in the off-pump CABG group. The mean urinary concentrations of hypoxanthine, xanthine and malondialdehyde expressed as creatinine ratios for the on-pump group increased significantly from 1.92+/-1.36, 6.06+/-3.62 and 0.21+/-0.07 before surgery to 11.88+/-5.77, 13.11+/-6.61 and 0.57+/-0.31 mmol/mol creatinine, respectively at arrival to the intensive care unit (ICU). During the next time-points, the purines and malondialdehyde decreased to 9.21+/-7.46, 7.55+/-3.95 and 0.32+/-0.13 mmol/mol creatinine, respectively after a 20 h stay at the ICU. For the off-pump CABG group, the mean ratios also increased significantly from 1.71+/-1.38, 2.01+/-0.96 and 0.16+/-0.10 before surgery to 4.73+/-3.19, 5.15+/-3.74 and 0.23+/-0.17 mmol/mol creatinine, respectively at arrival to the ICU. During the next time-points, the ratios of xanthine and malondialdehyde decreased to 3.80+/-2.92 and 0.24+/-0.13 mmol/mol creatinine, respectively. The ratio for hypoxanthine reached the highest ratio (6.97+/-5.67 mmol/mol creatinine) after a 9 h stay at the ICU, after which the ratio decreased to 5.98+/-5.56 mmol/mol creatinine after a 20 h stay at the ICU. However, all ratios from the on- and off-pump CABG patients still remained elevated compared with preoperative ratios. In addition, all ratios for the on-pump CABG group were elevated significantly at all time-points for xanthine, at time-points T2 and T4 for hypoxanthine and at time-point T2 for malondialdehyde as compared with the off-pump CABG group. CONCLUSIONS: Only mild signs of oxidative stress and no renal dysfunction were found during and after off-pump CABG compared with on-pump CABG.     

Valvular and coronary surgery in renal transplant patients

The Authors report aortic valvular replacement (AVR) and coronary artery bypass graft surgery (CABG) successfully performed in two renal transplant patients. The postoperative blood urea and creatinine levels were comparable to the preoperative values. The first patient underwent isolated AVR. The second patient had an initial AVR combined with CABG followed two years later by a further AVR for prosthetic dysfunction. For many reasons, coronary artery (CAD) and valvular diseases are not uncommon in renal transplant patients. Cardiac surgery is feasible without impairment of the renal function provided some precautions are taken, ie good mean perfusion pressure during cardiopulmonary bypass (CPB), adequate volume replacement, and selected use of mannitol and dopamine.     

Myocardial revascularization in the elderly using beating heart coronary artery bypass surgery

BACKGROUND: Beating heart or "off-pump" coronary artery bypass (OP-CAB) has become an accepted method of myocardial revascularization by reducing the perioperative morbidity related to cardiopulmonary bypass (CPB). However, the efficacy of OP-CAB has not been well established in the elderly patient population. METHODS: OP-CABs were performed in 53 patients aged 75 years and older, at Pitt County Memorial Hospital from January 1996 to October 1999, either through a median sternotomy or an anterior thoracotomy. These results were compared with 220 patients who underwent standard coronary artery bypass graft (CABG) operation using CPB during the same time period. RESULTS: Mean patient age for both groups was 79+/-0.5 years and preoperative risk factors were similar. There were no differences in postoperative myocardial infarction, atrial fibrillation, bleeding, neurologic complications, or renal failure. There were no deaths after OP-CAB, compared with the 7.6% operative mortality rate after CABG (p<0.05). The OP-CAB group had a significantly shorter postoperative length of stay (4.4+/-0.4 days vs. 8.4+/-0.6 days) and lower transfusion requirements (0.4+/-0.1 units packed red blood cells vs 1.9+/-0.2 units packed red blood cells) than the CABG group. CONCLUSIONS: Our data demonstrate that OP-CAB is a safe and efficacious method of myocardial revascularization in the elderly, and may actually be preferential in these patients when applicable.     

Results of open heart surgery in patients with impaired renal function as creatinine clearance below 30 ml/min. The effects of pulsatile perfusion

Twelve patients (pts) with coronary and/or valvular heart disease and preoperative creatinine clearance (Ccr) below 30 ml/min underwent cardiac surgery using cardiopulmonary bypass (CPB) with pulsatile (P:n = 7) and nonpulsatile (NP:n = 5) perfusion. Preoperative Ccr was 15.8 +/- 4.4 ml/min in the P group and 26.5 +/- 4.7 ml/min in the NP group. After surgery, the NP group showed significant increases in BUN and serum creatinine within a week, but the P group showed significant increase in BUN only. The NP group had a significant decrease in Ccr on the 7th postoperative day, but there was no significant change in the P group. Three patients, 2 from the NP group and one from the P group, died from complications (operative mortality: 14 vs 40%). These data suggested that P-CPB appeared to be advantageous in patients with preoperatively impaired renal function with low Ccr although many other factors might influence the outcome.     

Does off-pump coronary artery bypass reduce the incidence of clinically evident renal dysfunction after multivessel myocardial revascularization?

In this prospective, observational trial, we determined whether off-pump coronary artery bypass (OPCAB) was associated with less postoperative renal dysfunction (RD) compared with coronary bypass surgery with cardiopulmonary bypass (CABG). All patients undergoing primary, isolated coronary surgery at our institution in the year 2000 participated. Data collected on each patient included demographics, preoperative risk factors for RD, perioperative events, and serum creatinine concentrations from date of admission until discharge or death. The criteria for RD was both a >or=50% increase from preoperative creatinine and an absolute postoperative creatinine >or=2.0 mg/dL (177 microM). Student's t-test or the Fisher's exact test was used to compare groups. Stepwise multiple logistic regression identified determinants of RD; P < 0.05 significant. The CABG group (n = 119) differed from the OPCAB group (n = 220) with respect to age (64 +/- 13 versus 67 +/- 10 yr, P = 0.0074) and number of distal grafts (median 4 versus 3, P = 0.0003). Type of operation did not associate with the presence of postoperative RD: 18 (8.2%) of 220 OPCAB patients versus 12 (10%) of 119 CABG patients (P = 0.55). Our data suggest that choice of operative technique (OPCAB versus CABG) is not associated with reduced renal morbidity.     

Does off‐pump coronary artery bypass grafting beneficially affect renal function?

BACKGROUND: Off-pump coronary artery bypass grafting (CABG) has been reported to beneficially affect renal function, but this remains to be confirmed. The purpose of the present paper was to study the effects of off-pump CABG on renal function and analyse predictors of postoperative renal impairment in patients who received off-pump CABG. METHODS: A total of 451 patients who underwent isolated CABG between January 1999 and August 2003 were retrospectively studied. No patient was receiving dialysis. A total of 300 patients (228 men) underwent off-pump CABG (off-pump group) and 151 patients (104 men) underwent on-pump CABG (on-pump group). Perioperative serum creatinine levels and creatinine ratios (peak postoperative creatinine level/preoperative creatinine level) were compared between the groups. RESULTS: Renal impairment (serum creatinine >1.5 mg/dL) developed postoperatively in 12.7% of the off-pump group and 18.5% of the on-pump group (P = 0.1). The creatinine ratio was significantly lower in the off-pump group (1.2 +/- 0.4) than in the on-pump group (1.4 +/- 0.7, P = 0.003). Logistic regression analysis demonstrated that the strongest predictors of postoperative renal impairment in off-pump CABG were left ventricular dysfunction (odds ratio 10.8) and multivessel grafting (odds ratio 4.3). CONCLUSIONS: Off-pump CABG provides better renal protection than on-pump CABG. However, perioperative renal function should be closely monitored in patients who have left ventricular dysfunction or who undergo multivessel grafting, even when off-pump CABG is performed.     

A Meta‐Analysis of Renal Function After Adult Cardiac Surgery With Pulsatile Perfusion

The aim of this meta‐analysis was to determine whether pulsatile perfusion during cardiac surgery has a lesser effect on renal dysfunction than nonpulsatile perfusion after cardiac surgery in randomized controlled trials. MEDLINE, EMBASE, and the Cochrane Central Register of Controlled Trials were used to identify available articles published before April 25, 2014. Meta‐analysis was conducted to determine the effects of pulsatile perfusion on postoperative renal functions, as determined by creatinine clearance (CrCl), serum creatinine (Cr), urinary neutrophil gelatinase‐associated lipocalin (NGAL), and the incidences of acute renal insufficiency (ARI) and acute renal failure (ARF). Nine studies involving 674 patients that received pulsatile perfusion and 698 patients that received nonpulsatile perfusion during cardiopulmonary bypass (CPB) were considered in the meta‐analysis. Stratified analysis was performed according to effective pulsatility or unclear pulsatility of the pulsatile perfusion method in the presence of heterogeneity. NGAL levels were not significantly different between the pulsatile and nonpulsatile groups. However, patients in the pulsatile group had a significantly higher CrCl and lower Cr levels when the analysis was restricted to studies on effective pulsatile flow (P < 0.00001, respectively). The incidence of ARI was significantly lower in the pulsatile group (P < 0.00001), but incidences of ARF were similar. In conclusion, the meta‐analysis suggests that the use of pulsatile flow during CPB results in better postoperative renal function.     

Effects of pulsatile CPB on interleukin-8 and endothelin-1 levels

Studies on pulsatile and nonpulsatile perfusion have long been performed. However, investigators have not reached a conclusion on which is more effective. In the present study, pulsatile cardiopulmonary bypass (CPB) was investigated in terms of the effects on cytokines, endothelin, catecholamine, and pulmonary and renal functions. Twenty-four patients who underwent coronary artery bypass grafting were divided into a pulsatile CPB group and a nonpulsatile CPB group. Parameters examined were hemodynamics, interleukin-8 (IL-8), endothelin-1 (ET-1), epinephrine, norepinephrine, lactate, arterial ketone body ratio, urine volume, blood urea nitrogen, creatinine, renin activity, angiotensin-II, lactate dehydrogenase, plasma-free hemoglobin, tracheal intubation time, and respiratory index. The IL-8 at 0.5, 3, and 6 h after CPB, and ET-1 at 3, 6, 9, and 18 h after CPB were significantly lower in the pulsatile group. Both epinephrine and norepinephrine were significantly lower in the pulsatile group. The respiratory index was significantly higher in the pulsatile group. In the present study, inhibitory effects on cytokine activity, edema in pulmonary alveoli, and endothelial damage were shown in addition to the favorable effects on catecholamine level, renal function, and peripheral circulation that have already been documented.     

Acute renal failure following cardiac surgery.

BACKGROUND: Acute renal failure requiring dialysis (ARF-D) occurs in 1.5% of patients following cardiac surgery, and remains a cause of major morbidity and mortality. While some preoperative risk factors have been characterized, the influence of preoperative and intraoperative factors on the occurrence of ARF following cardiac surgery is less well understood. METHODS: Preoperative and intraoperative data on 2843 consecutive adult patients undergoing cardiac surgery with cardiopulmonary bypass (CPB) from February 1, 1995 to February 1, 1997 were recorded and entered into a computerized database. Two definitions of renal failure were employed: (i) ARF defined as a rise in serum creatinine (Cr) of 1 mg/dl above baseline; and (ii) ARF-D defined as the development of ARF for which some form of dialytic therapy was required. The association between preoperative and intraoperative variables and the development of ARF was assessed by multivariate logistic regression. RESULTS: A total of 2672 of the 2844 patients underwent isolated coronary artery bypass grafting (CABG) surgery, the remaining 172 underwent valve surgery with or without bypass grafting. Of the CABG patients 7.9% developed ARF and 0.7% developed ARF-D. The mortality for patients who developed ARF was 14% (OR 15, P = 0.0001) compared with 1% among those who did not develop ARF. The mortality for CABG patients who developed ARF-D was 28% (OR 20, P = 0.0001) compared with 1.8% among those who did not require dialysis. Variables that were significantly associated with the development of ARF by multivariate analysis included: increased age, elevated preoperative serum Cr, duration of CPB, presence of a carotid artery bruit, presence of diabetes, reduced cardiac ejection fraction and increased body weight. Variables independently associated with ARF-D included serum Cr, duration of CPB, carotid artery bruit and presence of diabetes. The utility of these models for predicting the development of ARF and ARF-D was confirmed by bootstrapping techniques. Because of the small number of patients who underwent valve surgery, none of these variables were significantly associated with the development of ARF or ARF-D in this group of patients. CONCLUSION: The development of ARF or ARF-D is associated with a high mortality following CABG surgery. We have identified perioperative variables, which may be useful in stratifying risk for the development of ARF.     

Does intensive perioperative dialysis improve the results of coronary artery bypass grafting in haemodialysed patients?

BACKGROUND: Between January 1996 and April 1998, 17 chronic haemodialysed patients underwent coronary artery bypass grafting (CABG). Two of them simultaneously had valve replacement. METHODS: Except for two cases in which CABG was performed in an emergency, 15 patients (CRF group) received 3 consecutive days of haemodialysis in the preoperative period, intraoperative haemodialysis connected to cardiac pulmonary bypass (CPB) and continuous hemodiafiltration in the early postoperative period. The perioperative clinical parameters of the CRF group were compared with those of 17 age-matched patients with normal renal function undergoing CABG as the control (NRF group). RESULTS: When the perioperative variables were compared, no significant differences were seen in total operation time and CPB time, but we noted significant increases in the mean volume of transfused blood in the 6 perioperative days, postoperative intubation time, postoperative fasting time, and time spent in the intensive care unit. Levels of central venous pressure, systolic blood pressure, respiratory index (PaO2/FiO2) and daily fluid balance of the CRF group were the same as the control group in the early postoperative period. In addition, the levels of serum creatinine, urea nitrogen, potassium and hematocrit of CRF group remained almost constant in the early postoperative period. After all, the hospital morbidity of the CRF group was not more serious than that of the NRF group, and hospital mortality of the CRF and NRF groups was 0%. CONCLUSIONS: Our intensive perioperative dialysis programme could successfully manage the perioperative clinical course of haemodialysed patients undergoing CABG.     

Serial changes in renal function in cardiac surgical patients

Cardiopulmonary bypass is widely believed to be injurious to renal function. The low incidence of renal dysfunction with modern techniques of bypass led us to reexamine this concept by monitoring urine output and creatinine clearance in 18 adult patients undergoing nonpulsatile, hemodilution cardiopulmonary bypass for coronary artery bypass grafting (12 patients) or valve procedures (6 patients). Samples were taken before, during (mean duration of bypass, 105 +/- 26 minutes [+/- standard deviation]), and every two hours after bypass for 24 hours. Urine output (42 +/- 37.7 mL/h) and creatinine clearance (57 +/- 40.4 mL/min) were surprisingly low in the period before cardiopulmonary bypass (all values normalized to a body surface area of 1.73 m2). Urine volumes rose to 305 +/- 149.6 mL/h and creatinine clearance to 252 +/- 176.9 mL/min during bypass and decreased to stable values after eight hours in the postoperative unit (urine output, approximately 60 mL/h, and creatinine clearance, approximately 75 mL/min). Renal dysfunction did not develop in any patient. Nine patients who required loop diuretics for low urine output 18 hours postoperatively had a sustained increase in both urine output and creatinine clearance lasting up to six hours. We conclude the following: modern techniques of cardiopulmonary bypass are not injurious to renal function; urine output and creatinine clearance are decreased before cardiopulmonary bypass, probably because of preoperative dehydration; and loop diuretics in the postoperative period increase both urine output and creatinine clearance for as long as six hours after administration.     

Minimally invasive direct coronary bypass versus cardiopulmonary technique: angiographic comparison

BACKGROUND: Studies comparing minimally invasive direct coronary artery bypass grafting (MIDCABG) with techniques using cardiopulmonary bypass (CPB) are needed. METHODS: Sixteen patients underwent single-vessel left internal thoracic artery-left anterior descending (LITA-LAD) MIDCABG through a left anterior thoracotomy, and 10 underwent multivessel bypass grafting that included a LITA-LAD, using CPB. Intraoperative completion angiography was performed on all LITA-LAD bypasses, and graded. One point each was given for: anastomotic patency, pedicle patency, intercostal obliteration, proper placement into the correct native coronary artery, and Thrombosis In Myocardial Ischemia grade III flow. RESULTS: There were no intraoperative deaths or morbidities. LITA takedown averaged 49 +/- 18.6 minutes for MIDCABG and 16 +/- 2.0 minutes for CPB CABG (p < 0.05). LITA length did not differ between groups (15.3 +/- 1.2 cm for MIDCABG, 14.3 +/- 1.08 cm for CPB CABG). Ischemic arrest time was significantly less for the CPB group (13.3 +/- 8.3 minutes versus 24.5 +/- 9.6 minutes; p < 0.05). Average grade for MIDCABG LITA-LAD was 4.06 +/- 0.98 points versus 4.77 +/- 0.98 points for CPB LITA-LAD bypass (p = not significant). CONCLUSIONS: Intraoperative completion angiography is feasible and, when combined with a grading system, may facilitate the comparison of MIDCABG with standard techniques.     

Report of a substudy on warm versus cold cardiopulmonary bypass: changes in creatinine clearance.

BACKGROUND: Renal dysfunction remains a major complication of cardiac operations. There is concern regarding the possibility of increased renal injury during warm cardiopulmonary bypass (CPB). Therefore, we tested the hypothesis that warm CPB is associated with a greater reduction in creatinine clearance after cardiac surgery than hypothermic CPB. METHODS: We randomly assigned 300 patients who had elective coronary artery bypass grafting to warm (35.5 to 36.5 degrees C) or cold (28 degrees C to 30 degrees C) CPB. Preoperative and peak postoperative serum creatinine values were recorded. Creatinine clearance was estimated using the Cockroft Gault equation. Univariate and multivariable analyses were performed to test the association of CPB temperature and perioperative change in creatinine clearance. RESULTS: Demographic variables were similar between groups. Multivariable analysis did not confirm an association between temperature and change in creatinine clearance (p = 0.87). CONCLUSIONS: We did not confirm an association between warm CPB and increased renal dysfunction after cardiac operations compared with hypothermic CPB.