Metabolic profiling of aortic stenosis and hypertrophic cardiomyopathy identifies mechanistic contrasts in substrate utilization.

Aortic stenosis (AS) and hypertrophic cardiomyopathy (HCM) are distinct disorders leading to left ventricular hypertrophy (LVH), but whether cardiac metabolism substantially differs between these in humans remains to be elucidated. We undertook an invasive (aortic root, coronary sinus) metabolic profiling in patients with severe AS and HCM in comparison with non-LVH controls to investigate cardiac fuel selection and metabolic remodeling. These patients were assessed under different physiological states (at rest, during stress induced by pacing). The identified changes in the metabolome were further validated by metabolomic and orthogonal transcriptomic analysis, in separately recruited patient cohorts. We identified a highly discriminant metabolomic signature in severe AS in all samples, regardless of sampling site, characterized by striking accumulation of long-chain acylcarnitines, intermediates of fatty acid transport across the inner mitochondrial membrane, and validated this in a separate cohort. Mechanistically, we identify a downregulation in the PPAR-α transcriptional network, including expression of genes regulating fatty acid oxidation (FAO). In silico modeling of ß-oxidation demonstrated that flux could be inhibited by both the accumulation of fatty acids as a substrate for mitochondria and the accumulation of medium-chain carnitines which induce competitive inhibition of the acyl-CoA dehydrogenases. We present a comprehensive analysis of changes in the metabolic pathways (transcriptome to metabolome) in severe AS, and its comparison to HCM. Our results demonstrate a progressive impairment of ß-oxidation from HCM to AS, particularly for FAO of long-chain fatty acids, and that the PPAR-α signaling network may be a specific metabolic therapeutic target in AS.

Arteriovenous fistula creation in a patient without a pulse: Vascular access in patients with left ventricular assist devices.

Left ventricular assist devices are used in heart failure patients as bridge to transplantation or increasingly as a destination therapy. These patients frequently have renal dysfunction and many reach end-stage renal failure. If haemodialysis is required, minimization of infection risk is essential. Arteriovenous grafts have been recommended for these patients due to hypothetical concerns regarding fistula maturation due to continuous flow. A case is described where a brachiocephalic arteriovenous fistula was successfully formed and used for dialysis without issue. This is one case of a small number in the literature where arteriovenous fistulas have been used in left ventricular assist device patients and it appears that concerns are unfounded and good outcomes have been reported. It would appear from this experience that approaches to vascular access for dialysis in patients with continuous-flow left ventricular assist devices are in accordance with vascular access guidelines and standard practice.

Multicentre double-blind randomized controlled trial of perhexiline as a metabolic modulator to augment myocardial protection in patients with left ventricular hypertrophy undergoing cardiac surgery.

OBJECTIVES: Patients undergoing cardiac surgery require adequate myocardial protection. Manipulating myocardial metabolism may improve the extent of myocardial protection. Perhexiline has been shown to be an effective anti-anginal agent due to its metabolic modulation properties by inhibiting the uptake of free fatty acids into the mitochondrion, and thereby promoting a more efficient carbohydrate-driven myocardial metabolism. Metabolic modulation may augment myocardial protection, particularly in patients with left ventricular hypertrophy (LVH) known to have a deranged metabolic state and are at risk of poor postoperative outcomes. This study aimed to evaluate the role of perhexiline as an adjunct in myocardial protection in patients with LVH secondary to aortic stenosis (AS), undergoing an aortic valve replacement (AVR). METHODS: In a multicentre double-blind randomized controlled trial of patients with AS undergoing AVR ± coronary artery bypass graft surgery, patients were randomized to preoperative oral therapy with either perhexiline or placebo. The primary end point was incidence of inotrope use to improve haemodynamic performance due to a low cardiac output state during the first 6 h of reperfusion, judged by a blinded end points committee. Secondary outcome measures included haemodynamic measurements, electrocardiographic and biochemical markers of new myocardial injury and clinical safety outcome measures. RESULTS: The trial was halted early on the advice of the Data Safety and Monitoring Board. Sixty-two patients were randomized to perhexiline and 65 to placebo. Of these, 112 (54 perhexiline and 48 placebo) patients received the intervention, remained in the trial at the time of the operation and were analysed. Of 110 patients who achieved the primary end point, 30 patients (16 perhexiline and 14 placebo) had inotropes started appropriately; there was no difference in the incidence of inotrope usage OR of 1.65 [confidence interval (CI): 0.67-4.06] P = 0.28. There was no difference in myocardial injury as evidenced by electrocardiogram odds ratio (OR) of 0.36 (CI: 0.07-1.97) P = 0.24 or postoperative troponin release. Gross secondary outcome measures were comparable between the groups. CONCLUSIONS: Perhexiline as a metabolic modulator to enhance standard myocardial protection does not provide an additional benefit in haemodynamic performance or attenuate myocardial injury in the hypertrophied heart secondary to AS. The role of perhexiline in cardiac surgery is limited.

The effect of perhexiline on myocardial protection during coronary artery surgery: a two-centre, randomized, double-blind, placebo-controlled trial.

OBJECTIVES: Perhexiline is thought to modulate metabolism by inhibiting mitochondrial carnitine palmitoyltransferase-1, reducing fatty acid uptake and increasing carbohydrate utilization. This study assessed whether preoperative perhexiline improves markers of myocardial protection in patients undergoing coronary artery bypass graft surgery and analysed its effect on the myocardial metabolome. METHODS: In a prospective, randomized, double-blind, placebo-controlled trial, patients at two centres were randomized to receive either oral perhexiline or placebo for at least 5 days prior to surgery. The primary outcome was a low cardiac output episode in the first 6 h. All pre-specified analyses were conducted according to the intention-to-treat principle with a statistical power of 90% to detect a relative risk of 0.5 and a conventional one-sided α-value of 0.025. A subset of pre-ischaemic left ventricular biopsies was analysed using mass spectrometry-based metabolomics. RESULTS: Over a 3-year period, 286 patients were randomized, received the intervention and were included in the analysis. The incidence rate of a low cardiac output episode in the perhexiline arm was 36.7% (51/139) vs 34.7% (51/147) in the control arm [odds ratio (OR) 0.92, 95% confidence interval (CI) 0.56-1.50, P = 0.74]. Perhexiline was associated with a reduction in the cardiac index at 6 h [difference in means 0.19, 95% CI 0.07-0.31, P = 0.001] and an increase in inotropic support in the first 12 h (OR 0.55, 95% CI 0.34-0.89, P = 0.015). There were no significant differences in myocardial injury with troponin-T or electrocardiogram, reoperation, renal dysfunction or length of stay. No difference in the preischaemic left ventricular metabolism was identified between groups on metabolomics analysis. CONCLUSIONS: Preoperative perhexiline does not improve myocardial protection in patients undergoing coronary surgery and in fact reduced perioperative cardiac output, increasing the need for inotropic support. Perhexiline has no significant effect on the mass spectrometry-visible polar myocardial metabolome in vivo in humans, supporting the suggestion that it acts via a pathway that is independent of myocardial carnitine palmitoyltransferase inhibition and may explain the lack of clinical benefit observed following surgery. CLINICALTRIALSGOV ID: NCT00845364.

Clinical outcomes of Carbomedics Top Hat valve with a robust follow-up system.

AIM: Late failure of bioprosthetic valves may limit their use in patients < 60 years. The superior hemodynamic performance offered by the Carbomedics Top Hat supraannular valve enables greater effective orifice areas to be achieved. The aim of this study was to assess the clinical outcomes of this valve, using a robust follow-up system. METHODS: Patients who underwent aortic valve replacement with or without coronary artery bypass grafting between July 1997 and January 2010 with Carbomedics supraannular Top Hat valves were identified. Details of readmissions and late deaths were obtained from the National Hospital Episodes Statistics data and the Office of National Statistics, tracked by the Quality and Outcomes Research Unit. Late complications associated with this prosthesis were evaluated. RESULTS: Of 253 patients identified, 181 underwent isolated aortic valve replacement and 72 had aortic valve replacement with coronary artery bypass grafting. The 30-day mortality was 1.6%, and 5- and 10-year survival rates were 91.4% and 80.5%, respectively. Detailed readmission data were available after 2001 (n = 170). Two (1.2%) patients required reoperation for endocarditis and pannus formation. Of the 17 late deaths in this subset, 4 were attributable to cardiac causes. One patient was treated for heart failure, and 2 developed bleeding complications. CONCLUSIONS: Implantation of the Carbomedics Top Hat supraannular valve in our unit resulted in satisfactory in-hospital and midterm survival with low incidences of endocarditis and late heart failure.

The role of HIFs in ischemia-reperfusion injury.

The reduction or cessation of the blood supply to an organ results in tissue ischemia. Ischemia can cause significant tissue damage, and is observed as a result of a thrombosis, as part of a disease process, and during surgery. However, the restoration of the blood supply often causes more damage to the tissue than the ischemic episode itself. Research is therefore focused on identifying the cellular pathways involved in the protection of organs from the damage incurred by this process of ischemia reperfusion (I/R). The hypoxia-inducible factors (HIFs) are a family of heterodimeric transcription factors that are stabilized during ischemia. The genes that are expressed downstream of HIF activity enhance oxygen-independent ATP generation, cell survival, and angiogenesis, amongst other phenotypes. They are, therefore, important factors in the protection of tissues from I/R injury. Interestingly, a number of the mechanisms already known to induce organ protection against I/R injury, including preconditioning, postconditioning, and activation of signaling pathways such as adenosine receptor signaling, converge on the HIF system. This review describes the evidence for HIFs playing a role in I/R protection mediated by these factors, highlights areas that require further study, and discuss whether HIFs themselves are good therapeutic targets for protecting tissues from I/R injury.

Relationship between plasma, atrial and ventricular perhexiline concentrations in humans: insights into factors affecting myocardial uptake.

AIM: Little is known regarding the steady-state uptake of drugs into the human myocardium. Perhexiline is a prophylactic anti-anginal drug which is increasingly also used in the treatment of heart failure and hypertrophic cardiomyopathy. We explored the relationship between plasma perhexiline concentrations and its uptake into the myocardium. METHODS: Blood, right atrium ± left ventricle biopsies were obtained from patients treated with perhexiline for a median of 8.5 days before undergoing coronary surgery in the perhexiline arm of a randomized controlled trial. Perhexiline concentrations in plasma and heart tissue were determined by HPLC. RESULTS: Atrial biopsies were obtained from 94 patients and ventricular biopsies from 28 patients. The median plasma perhexiline concentration was within the therapeutic range at 0.24 mg l⁻¹ (IQR 0.12-0.44), the median atrial concentration was 6.02 mg kg⁻¹ (IQR 2.70-9.06) and median ventricular concentration was 10.0 mg kg⁻¹ (IQR 5.76-13.1). Atrial (r² = 0.76) and ventricular (r² = 0.73) perhexiline concentrations were closely and directly correlated with plasma concentrations (both P < 0.001). The median atrial : plasma ratio was 21.5 (IQR 18.1-27.1), ventricular : plasma ratio was 34.9 (IQR 24.5-55.2) and ventricular : atrial ratio was 1.67 (IQR 1.39-2.22). Using multiple regression, the best model for predicting steady-state atrial concentration included plasma perhexiline, heart rate and age (r² = 0.83). Ventricular concentrations were directly correlated with plasma perhexiline concentration and length of therapy (r² = 0.84). CONCLUSIONS: This study demonstrates that plasma perhexiline concentrations are predictive of myocardial drug concentrations, a major determinant of drug effect. However, net myocardial perhexiline uptake is significantly modulated by patient age, potentially via alteration of myocardial:extracardiac drug uptake.

The European Association for Cardio-Thoracic Surgery (EACTS) database: an introduction.

OBJECTIVES: Continuous monitoring of surgical outcomes through benchmarking and the identification of best practices has become increasingly important. A structured approach to data collection, coupled with validation, analysis and reporting, is a powerful tool in these endeavours. However, inconsistencies in standards and practices have made comparisons within and between European countries cumbersome. The European Association for Cardio-Thoracic Surgery (EACTS) has established a large international database with the goals of (i) working with other organizations towards universal data collection and creating a European-wide repository of information on the practice of cardio-thoracic surgery, and (ii) disseminating that information in scientific, peer-reviewed articles. We report on the process of data collection, as well as on an overview of the data in the database. METHODS: The EACTS Database Committee met for the first time in Monaco, September 2002, to establish the ground rules for the process of setting up the database. Subsequently, data have been collected and merged by Dendrite Clinical Systems Ltd. RESULTS: As of December 2008, the database included 1,074,168 patient records from 366 hospitals located in 29 countries. The latest submission from the years 2006-08 included 404,721 records. The largest contributors were the UK (32.0%), Germany (20.9%) and Belgium (7.3%). Isolated coronary bypass surgery was the most frequently performed operation; the proportion of surgical workload that comprised isolated coronary artery bypass grafting varied from country to country: 30% in Spain and almost 70% in Denmark. Isolated valve procedures constituted 12% of all procedures in Norway and 32% in Spain. Baseline demographics showed an increase in the mean age and the percentage of patients that were female over time. Remarkably, the mortality rates for all procedures declined over the period analysed, to 2.2% (95% confidence interval [CI] 2.2-2.3%) for isolated coronary bypass, 3.4% (95% CI 3.3-3.5%) for isolated valve and 6.2% (95% CI 6.0-6.5%) for bypass + valve procedures. CONCLUSION: The EACTS database has proven to be an important step forward in providing opportunities for monitoring cardiac surgical care across Europe. As the database continues to expand, it will facilitate research projects, establish benchmarking standards and identify potential areas for quality improvements.

The new EuroSCORE II does not improve prediction of mortality in high-risk patients undergoing cardiac surgery: a collaborative analysis of two European centres.

OBJECTIVES: Prediction of operative risk in adult patients undergoing cardiac surgery remains a challenge, particularly in high-risk patients. In Europe, the EuroSCORE is the most commonly used risk-prediction model, but is no longer accurately calibrated to be used in contemporary practice. The new EuroSCORE II was recently published in an attempt to improve risk prediction. We sought to assess the predictive value of EuroSCORE II compared with the original EuroSCOREs in high-risk patients. METHODS: Patients who underwent surgery between 1 April 2006 and 31 March 2011 with a preoperative logistic EuroSCORE ≥ 10 were identified from prospective cardiac surgical databases at two European institutions. Additional variables included in EuroSCORE II, but not in the original EuroSCORE, were retrospectively collected through patient chart review. The C-statistic to predict in-hospital mortality was calculated for the additive EuroSCORE, logistic EuroSCORE and EuroSCORE II models. The Hosmer-Lemeshow test was used to assess model calibration by comparing observed and expected mortality in a number of risk strata. The fit of EuroSCORE II was compared with the original EuroSCOREs using Akaike's Information Criterion (AIC). RESULTS: A total of 933 patients were identified; the median additive EuroSCORE was 10 (interquartile range [IQR] 9-11), median logistic EuroSCORE 15.3 (IQR 12.0-24.1) and median EuroSCORE II 9.3 (5.8-15.6). There were 90 (9.7%) in-hospital deaths. None of the EuroSCORE models performed well with a C-statistic of 0.67 for the additive EuroSCORE and EuroSCORE II, and 0.66 for the logistic EuroSCORE. Model calibration was poor for the EuroSCORE II (chi-square 16.5; P = 0.035). Both the additive EuroSCORE and logistic EuroSCORE had a numerically better model fit, the additive EuroSCORE statistically significantly so (difference in AIC was -5.66; P = 0.017). CONCLUSIONS: The new EuroSCORE II does not improve risk prediction in high-risk patients undergoing adult cardiac surgery when compared with original additive and logistic EuroSCOREs. The key problem of risk stratification in high-risk patients has not been addressed by this new model. Future iterations of the score should explore more advanced statistical methods and focus on developing procedure-specific algorithms. Moreover, models that predict complications in addition to mortality may prove to be of increasing value.

A systematic review of risk prediction in adult cardiac surgery: considerations for future model development.

OBJECTIVES: Risk prediction in adult patients undergoing cardiac surgery remains inaccurate and should be further improved. Therefore, we aimed to identify risk factors that are predictive of mortality, stroke, renal failure and/or length of stay after adult cardiac surgery in contemporary practice. METHODS: We searched the Medline database for English-language original contributions from January 2000 to December 2011 to identify preoperative independent risk factors of one of the following outcomes after adult cardiac surgery: death, stroke, renal failure and/or length of stay. Two investigators independently screened the studies. Inclusion criteria were (i) the study described an adult cardiac patient population; (ii) the study was an original contribution; (iii) multivariable analyses were performed to identify independent predictors; (iv) ≥ 1 of the predefined outcomes was analysed; (v) at least one variable was an independent predictor, or a variable was included in a risk model that was developed. RESULTS: The search yielded 5768 studies. After the initial title screening, a second screening of the full texts of 1234 studies was performed. Ultimately, 844 studies were included in the systematic review. In these studies, we identified a large number of independent predictors of mortality, stroke, renal failure and length of stay, which could be categorized into variables related to: disease pathology, planned surgical procedure, patient demographics, patient history, patient comorbidities, patient status, blood values, urine values, medication use and gene mutations. Many of these variables are frequently not considered as predictive of outcomes. CONCLUSIONS: Risk estimates of mortality, stroke, renal failure and length of stay may be improved by the inclusion of additional (non-traditional) innovative risk factors. Current and future databases should consider collecting these variables.

Subtle changes in renal function are associated with differences in late survival following adult cardiac surgery.

OBJECTIVES: To determine the predictors of post-operative renal function following adult cardiac surgery, and to assess the influence of this on late survival. METHODS: Prospectively collected data were analysed on 8032 patients who underwent coronary artery bypass grafting, valve surgery or combined procedures from 1 January 1998 until 31 December 2008, who did not require preoperative renal replacement therapy. The estimated glomerular filtration rate (eGFR) was calculated by the Modification of Diet in Renal Disease formula accounting for ethnicity pre-operatively, post-operatively on the fourth post-operative day, and the post-operative nadir based upon the peak post-operative creatinine within 30 days of surgery. Late survival data were obtained from the UK Central Cardiac Audit Database (CCAD). Appropriate frailty analyses were conducted in R and model fit was compared using Aikaike's Information Criterion. Initial analysis intended to determine predictors of post-operative renal function including pre-operative eGFR, EuroSCORE and surgical procedure including the operative procedure and bypass time. Further analysis examined its influence on late survival. RESULTS: Median follow-up was 72 months (IQR 48-105) during which there were 904 late deaths. The most powerful predictor of the day 4 eGFR was the pre-operative eGFR but other factors contributed including increasing EuroSCORE and bypass time. The pre-operative eGFR was shown to be a strong and independent predictor of late outcome (P = 0.0001, HR 0.497 95%CI 0.434-564); however, model fit was significantly improved using the day 4 eGFR (P = 0.0001, HR 0.43 95%CI 0.385-0.482). No specific change in individual renal function was identified as a predictor of adverse late survival, and neither the pre-operative nor day 4 eGFR was predictive of the nadir of renal function. CONCLUSIONS: Subtle early changes in renal function at the time of surgery are powerful predictors of adverse late outcome and can be predicted by pre-operative renal function.

Contemporary outcomes of urgent coronary artery bypass graft surgery following non-ST elevation myocardial infarction: urgent coronary artery bypass graft surgery consistently outperforms Global Registry of Acute Coronary Events predicted survival.

OBJECTIVES: The Global Registry of Acute Coronary Events (GRACE) registry reported that the in-hospital risk of death from non-ST elevation myocardial infarction (NSTEMI) is 5%, with an 11% mortality by 6 months. Prospective Registry of Acute Ischaemic Syndromes in the UK demonstrated that the overall risk of death from NSTEMI over 4 years is 25%. In GRACE, while 28% of patients received percutaneous intervention, only 10% received coronary artery bypass graft (CABG). Results of urgent CABG surgery following NSTEMI are difficult to interpret as these often include patients who have had STEMIs and urgent surgery. With increasing multidisciplinary assessment of patients with acute coronary syndromes (ACS), accurate data collection on the outcome of such patients could inform correct revascularization strategy. METHODS: Three hundred and forty-two consecutive patients who had undergone urgent CABG from April 2004 to April 2009 at a single institution were identified. The GRACE predicted mortality was calculated from hospital records and patients categorized into three groups based upon their predicted risk. Late survival data were obtained from the UK Office of National Statistics. RESULTS: The GRACE score could be calculated in 270 patients with a confirmed diagnosis of NSTEMI. Of the 304 probable patients with NSTEMI, there were 5 in-hospital deaths (1.6%). Survival at 6 months was higher than GRACE predicted mortality in all groups. At 6 months the predicted versus observed mortality in the low-risk group was 4 versus 2% (P = 0.05), in the medium-risk group it was 12.5 versus 1.9% (P = 0.0001) and in the high-risk group it was 25 versus 20% (P = 0.45). CONCLUSIONS: In-hospital CABG performed after NSTEMI is associated with a low-mortality risk and survival significantly better than that predicted by the GRACE score.

Changes in cardiac substrate transporters and metabolic proteins mirror the metabolic shift in patients with aortic stenosis.

In the hypertrophied human heart, fatty acid metabolism is decreased and glucose utilisation is increased. We hypothesized that the sarcolemmal and mitochondrial proteins involved in these key metabolic pathways would mirror these changes, providing a mechanism to account for the modified metabolic flux measured in the human heart. Echocardiography was performed to assess in vivo hypertrophy and aortic valve impairment in patients with aortic stenosis (n = 18). Cardiac biopsies were obtained during valve replacement surgery, and used for western blotting to measure metabolic protein levels. Protein levels of the predominant fatty acid transporter, fatty acid translocase (FAT/CD36) correlated negatively with levels of the glucose transporters, GLUT1 and GLUT4. The decrease in FAT/CD36 was accompanied by decreases in the fatty acid binding proteins, FABPpm and H-FABP, the ß-oxidation protein medium chain acyl-coenzyme A dehydrogenase, the Krebs cycle protein α-ketoglutarate dehydrogenase and the oxidative phosphorylation protein ATP synthase. FAT/CD36 and complex I of the electron transport chain were downregulated, whereas the glucose transporter GLUT4 was upregulated with increasing left ventricular mass index, a measure of cardiac hypertrophy. In conclusion, coordinated downregulation of sequential steps involved in fatty acid and oxidative metabolism occur in the human heart, accompanied by upregulation of the glucose transporters. The profile of the substrate transporters and metabolic proteins mirror the metabolic shift from fatty acid to glucose utilisation that occurs in vivo in the human heart.

Glucose-insulin-potassium reduces the incidence of low cardiac output episodes after aortic valve replacement for aortic stenosis in patients with left ventricular hypertrophy: results from the Hypertrophy, Insulin, Glucose, and Electrolytes (HINGE) trial.

BACKGROUND: Patients undergoing aortic valve replacement for critical aortic stenosis often have significant left ventricular hypertrophy. Left ventricular hypertrophy has been identified as an independent predictor of poor outcome after aortic valve replacement as a result of a combination of maladaptive myocardial changes and inadequate myocardial protection at the time of surgery. Glucose-insulin-potassium (GIK) is a potentially useful adjunct to myocardial protection. This study was designed to evaluate the effects of GIK infusion in patients undergoing aortic valve replacement surgery. METHODS AND RESULTS: Patients undergoing aortic valve replacement for aortic stenosis with evidence of left ventricular hypertrophy were randomly assigned to GIK or placebo. The trial was double-blind and conducted at a single center. The primary outcome was the incidence of low cardiac output syndrome. Left ventricular biopsies were analyzed to assess changes in 5' adenosine monophosphate-activated protein kinase (AMPK), Akt phosphorylation, and protein O-linked ß-N-acetylglucosamination (O-GlcNAcylation). Over a 4-year period, 217 patients were randomized (107 control, 110 GIK). GIK treatment was associated with a significant reduction in the incidence of low cardiac output state (odds ratio, 0.22; 95% confidence interval, 0.10 to 0.47; P=0.0001) and a significant reduction in inotrope use 6 to 12 hours postoperatively (odds ratio, 0.30; 95% confidence interval, 0.15 to 0.60; P=0.0007). These changes were associated with a substantial increase in AMPK and Akt phosphorylation and a significant increase in the O-GlcNAcylation of selected protein bands. CONCLUSIONS: Perioperative treatment with GIK was associated with a significant reduction in the incidence of low cardiac output state and the need for inotropic support. This benefit was associated with increased signaling protein phosphorylation and O-GlcNAcylation. Multicenter studies and late follow-up will determine whether routine use of GIK improves patient prognosis.

Reduced negative surface charge on arterial endothelium explains accelerated atherosclerosis in type 2 diabetic patients.

Reduced endothelial surface charge markedly increases the rate of LDL uptake into blood vessels. Previous work in the streptozotocin diabetic rat reported reduced endothelial surface charge. We compared endothelial surface charge density in internal mammary artery rings from patients with type 2 diabetes (n = 12) and from non diabetic patients undergoing coronary artery bypass grafting, and observed a substantial (52%) reduction in the former. This was associated with higher plasma sialic acid levels suggesting loss of sialic acid residues from the glycocalyx as a possible mechanism.

Patient-prosthesis mismatch in patients with aortic stenosis undergoing isolated aortic valve replacement does not affect survival.

BACKGROUND: Data suggest that patient-prosthesis mismatch (PPM) adversely effects late survival after aortic valve replacement (AVR). This study examined the incidence and implications of PPM in patients undergoing isolated AVR. METHODS: Prospectively collected data on patients undergoing isolated AVR for aortic stenosis between January 1, 1997 and December 31, 2007 were analyzed. The projected effective valve orifice area from in vivo data was indexed to body surface area (EOAi). PPM was defined as moderate for EOAi of < or = 0.85 cm(2)/m(2) and severe if < or = 0.6 cm(2)/m(2). The reference group comprised patients with EOAi > 0.85 cm(2)/m(2). The effect of PPM on postoperative survival was assessed by multivariate analysis. RESULTS: Of 801 patients, PPM was severe in 48 (6.0%), moderate in 462 (57.8%), and nonexistent in 291 (36.4%). Mismatch was associated with increasing age and female gender, thus resulting in an increase in the EuroSCORE (reference group, 4.9 +/- 2.6; moderate PPM, 5.8 +/- 2.4; and severe PPM, 6.1+/-2.1; p < 0.001). PPM did not significantly increase hospital mortality. Four deaths occurred in the reference group (1.4%), 12 in the moderate PPM (2.6%), and none in the severe PPM group (p = 0.311). The 5-year survival estimates were 83% in reference, 86% in moderate PPM, and 89% in severe PPM (p = 0.25). By multivariate analysis, PPM was not an independent risk factor for reduced in-hospital or late survival. CONCLUSIONS: Moderate PPM is common in patients undergoing AVR for aortic stenosis, but severe mismatch is rare. Patients with PPM have similar early and late postoperative survival rate.

Mild renal dysfunction predicts in-hospital mortality and post-discharge survival following cardiac surgery.

OBJECTIVES: To assess the impact of preoperative renal dysfunction on in-hospital mortality and late survival outcome following adult cardiac surgery. METHODS: Prospectively collected data were analysed on 7621 consecutive patients not requiring preoperative renal-replacement therapy, who underwent CABG, valve surgery or combined procedures from 1/1/98 to 1/12/06. Preoperative estimated glomerular filtration rate was calculated using Cockcroft-Gault formula. Patients were classified in the four chronic kidney disease (CKD) stage classes defined by the National Kidney Foundation Disease Outcome Quality Initiative Advisory Board. Late survival data were obtained from the UK Central Cardiac Audit Database. RESULTS: There were 243 in-hospital deaths (3.2%). There was a stepwise increase in operative mortality with each CKD class independent of the type of surgery. Multivariate analysis confirmed CKD class to be an independent predictor of in-hospital mortality (class 2 OR 1.45, 95% CI 1.1-2.35, p=0.001; class 3 OR 2.8, 95% CI 1.68-4.46, p=0.0001; class 4 OR 7.5, 95% CI 3.76-15.2, p=0.0001). The median follow-up after surgery was 42 months (IQR 18-74) and there were 728 late deaths. Survival analysis using a Cox regression model confirmed CKD class to be an independent predictor of late survival (class 2 HR 1.2, 95% CI 1.1-1.6, p=0.0001; class 3 HR 1.95, 95% CI 1.6-2.4, p=0.0001; and class 4 HR 3.2, 95% CI 2.2-4.6, p=0.0001). Ninety-eight percent (7517/7621) of patients had a preoperative creatinine <200 micromol/l, which is not included as a risk factor in most risk stratification systems. CONCLUSIONS: Mild renal dysfunction is an important independent predictor of in-hospital and late mortality in adult patients undergoing cardiac surgery.

Bleeding in cardiac surgery: the use of aprotinin does not affect survival.

OBJECTIVE: The antifibrinolytic drug aprotinin has been the most widely used agent to reduce bleeding and its complications in cardiac surgery. Several randomized trials and meta-analyses have demonstrated it to be effective and safe. However, 2 recent reports from a single database have implicated the use of aprotinin as a risk for postoperative complications and reduced long-term survival. METHODS: In this single-institution observational study involving 7836 consecutive patients (1998-2006), we assessed the safety of using aprotinin in risk reduction strategy for postoperative bleeding. RESULTS: Aprotinin was used in 44% of patients. Multivariate analysis identified aprotinin use in risk reduction for reoperation for bleeding (odds ratio, 0.51; 95% confidence interval, 0.36-0.72; P = .001) and need for blood transfusion postoperatively (odds ratio, 0.67; 95% confidence interval, 0.57-0.79; P = .0002). The use of aprotinin did not affect in-hospital mortality (odds ratio, 1.03; 95% confidence interval, 0.71-1.49; P = 0.73), intermediate-term survival (median follow-up, 3.4 years; range, 0-8.9 years; hazard ratio, 1.09; 95% confidence interval, 0.93-1.28; P = .30), incidence of postoperative hemodialysis (odds ratio, 1.16; 95% confidence interval, 0.73-1.85; P = .49), and incidence of postoperative renal dysfunction (odds ratio, 0.78; 95% confidence interval, 0.59-1.03; P = .07). CONCLUSION: This study demonstrates that aprotinin is effective in reducing bleeding after cardiac surgery, is safe, and does not affect short- or medium-term survival.