High lactate levels are predictors of major complications after cardiac surgery.

Although hyperlactatemia after cardiac surgery is common, the implications of raised levels remain controversial. The aim of this study was to evaluate whether high lactate levels after cardiac surgery are predictors of major complications including mortality. This was a substudy of TRACS (Transfusion Requirements After Cardiac Surgery), which was designed as a prospective, randomized, controlled trial evaluating the effects of a transfusion strategy on morbidity and mortality. Of the 502 patients enrolled, 52 (10%) had at least 1 major complication. Patients with complications were older, had a higher EuroSCORE, lower left ventricular ejection fraction, lower preoperative hemoglobin, a higher prevalence of renal disease, and received more blood transfusions than the group without complications. Lactate levels were higher in the group with complications at the end of surgery (3.6 mmol/L [2.8-5.1] vs 3.3 mmol/L [2.2-4.8]; P = .018), immediately after intensive care unit (ICU) admission (0 hour) (4.4 mmol/L [3.1-8.4] vs 4 mmol/L [2.6-6.4]; P = .048); 6 hours (4 mmol/L [2.7-5.8] vs 2.6 mmol/L [2-3.6], P < .001), and 12 hours after admission (2.3 mmol/L [1.8-3.2] vs 1.7 mmol/L [1.3-2]; P < .001). In a multivariate model, higher age (odds ratio [OR], 1.048, 95% confidence interval [CI], 1.011-1.086; P = .010), left ventricular ejection fraction (LVEF) lower than 40% (OR, 3.03; 95% CI, 1.200-7.510; P = .019 compared with LVEF of 40%-59%; OR, 3.571; 95% CI, 1.503-8.196; P = .004 compared with LVEF higher than 60%), higher EuroSCORE (OR, 1.138; 95% CI; 1.007-1.285; P = .038), red blood cell transfusion (OR, 1.230; 95% CI, 1.086-1.393; P = .001), and lactate levels 6 hours after ICU admission (OR, 3.28, 95% CI; 1.61-6.69; P = .001) are predictors of major complications. Hyperlactatemia 6 hours after ICU admission is an independent risk factor for worse outcomes in adult patients after cardiac surgery.

Hajjar LA ，Almeida JP ，Fukushima JT ，Rhodes A ，Vincent JL ，Osawa EA ，Galas FR ... -  《-》

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.

Popov AF ，Schulz EG ，Schmitto JD ，Coskun KO ，Tzvetkov MV ，Kazmaier S ，Zimmermann J ，Schöndube FA ，Quintel M ，Hinz J ... -  《-》

Mortality prediction after cardiac surgery: blood lactate is indispensible.

Blood lactate is accepted as a mortality risk marker in intensive care units (ICUs), especially after cardiac surgery. Unfortunately, most of the commonly used ICU risk stratification scoring systems did not include blood lactate as a variable. We hypothesized that blood lactate alone can predict the risk of mortality after cardiac surgery with an accuracy that is comparable to those of other complex models. We therefore evaluated its accuracy at mortality prediction and compared it with that of other widely used complex scoring models statistically. We prospectively collected data of all consecutive adult patients who underwent cardiac surgery between January 1, 2007, and December 31, 2009. By using χ2 statistics, a blood lactate-based scale (LacScale) with only four cutoff points was constructed in a developmental set of patients (January 1, 2007, and May 31, 2008). LacScale included five categories: 0 (≤ 1.7 mmol/L); 1 (1.8-5.9 mmol/L), 2 (6.0-9.3 mmol/L), 3 (9.4-13.3 mmol/L), and 4 (≥ 13.4 mmol/L). Its accuracy at predicting ICU mortality was evaluated in another independent subset of patients (validation set, June 1, 2008, and December 31, 2009) on both study-population level (calibration analysis, overall correct classification) and individual-patient-risk level (discrimination analysis, ROC statistics). The results were then compared with those obtained from other widely used postoperative models in cardiac surgical ICUs (Sequential Organ Failure Assessment [SOFA] score, Simplified Acute Physiology Score II [SAPS II], and Acute Physiology and Chronic Health Evaluation II [APACHE II] score). ICU mortality was 5.8% in 4,054 patients. LacScale had a reliable calibration in the validation set (2,087 patients). It was highly accurate in predicting ICU mortality with an area under the ROC curve (area under curve [AUC]; discrimination) of 0.88. This AUC was significantly larger than that of all the other models (SOFA 0.83, SAPS II: 0.79 and APACHE II: 0.76) according to DeLong's comparison. Integrating the LacScale in those scores further improved their accuracy by increasing their AUCs (0.88, 0.81, and 0.80, respectively). This improvement was also highly significant. Blood lactate accurately predicts mortality at both individual patient risk and patient cohort levels. Its precision is higher than that of other commonly used "complex" scoring models. The proposed LacScale is a simple and highly reliable model. It can be used (at bedside without electronic calculation) as such or integrated in other models to increase their accuracy.

Badreldin AM ，Doerr F ，Elsobky S ，Brehm BR ，Abul-dahab M ，Lehmann T ，Bayer O ，Wahlers T ，Hekmat K ... -  《-》

Prolonged QTc affects short-term and long-term outcomes in patients with normal left ventricular function undergoing cardiac surgery.

Although it is known that preoperative decreased left ventricular ejection fraction (LVEF) is a risk for morbidity and mortality after cardiac surgery, there are no reliable markers of risk in patients with preserved LVEF. This study examines whether a prolonged QTc interval is associated with adverse outcomes in patients with preoperative LVEF greater than 40% undergoing cardiac surgery. A retrospective chart review of patients who had cardiac surgery at St. Paul's Hospital in Vancouver, Canada, between 2004 and 2009, who had a preoperative LVEF greater than 40%, was undertaken. We tested for association of preoperative prolonged QTc interval with mortality and morbidity using unadjusted and adjusted analyses. Five-hundred and fifty-five patients with a preoperative LVEF greater than 40% were included in the study; 496 (89.4%) had cardiopulmonary bypass and the remainder were off pump. Preoperative prolonged QTc was associated with increased mortality at 30 days (P < .01), 90 days (P < .01), and 8 years (P < .01), and these results remained significant after adjusting for the clinical variables significantly associated with mortality (8-year odds ratio, 2.42; 95% confidence interval, 1.34-4.34; P = .003). Similar results were found when the analysis was restricted to the more homogeneous group of patients undergoing on-pump coronary artery bypass (CABG, n = 408). Prolonged QTc was also associated with prolonged intensive care unit stay (P = .02), prolonged hospital stay (P < .01), development of atrial arrhythmias (P = .02), and low cardiac output syndrome (on-pump CABG, P = .02). In patients undergoing cardiac surgery and a preoperative LVEF greater than 40%, a prolonged QTc interval is associated with increased short-term and long-term mortality and increased perioperative morbidity, and therefore should be considered when assessing risk preoperatively.

Anantasit N ，Boyd JH ，Russell JA ，Fjell CD ，Lichtenstein SV ，Walley KR ... -  《-》

Evaluation of continuous veno-venous hemofiltration for the treatment of cardiogenic shock in conjunction with acute renal failure after cardiac surgery.

Vidal S ，Richebé P ，Barandon L ，Calderon J ，Tafer N ，Pouquet O ，Fournet N ，Janvier G ... -  《-》