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Background: Predicting relapses of post-operative complications in obese patients who undergo cardiac surgery is significantly complicated by persistent metabolic maladaptation associated with obesity. Despite studies supporting the linkages of increased systemic branched-chain amino acids (BCAAs) driving the pathogenesis of obesity, metabolome wide studies have either supported or challenged association of circulating BCAAs with cardiovascular diseases (CVDs). Objective: We interrogated whether BCAA catabolic changes precipitated by obesity in the heart and adipose tissue can be reliable prognosticators of adverse outcomes following cardiac surgery. Our study specifically clarified the correlation between BCAA catabolizing enzymes, cellular BCAAs and branched-chain keto acids (BCKAs) with the severity of cardiometabolic outcomes in obese patients pre and post cardiac surgery. Methods: Male and female patients of ages between 44 and 75 were stratified across different body mass index (BMI) (non-obese = 17, pre-obese = 19, obese class I = 14, class II = 17, class III = 12) and blood, atrial appendage (AA), and subcutaneous adipose tissue (SAT) collected during cardiac surgery. Plasma and intracellular BCAAs and BC ketoacids (BCKAs), tissue mRNA and protein expression and activity of BCAA catabolizing enzymes were assessed and correlated with clinical parameters. Results: Intramyocellular, but not systemic, BCAAs increased with BMI in cardiac surgery patients. In SAT, from class III obese patients, mRNA and protein expression of BCAA catabolic enzymes and BCKA dehydrogenase (BCKDH) enzyme activity was decreased. Within AA, a concomitant increase in mRNA levels of BCAA metabolizing enzymes was observed, independent of changes in BCKDH protein expression or activity. BMI, indices of tissue dysfunction and duration of hospital stay following surgery correlated with BCAA metabolizing enzyme expression and metabolite levels in AA and SAT. Conclusion: This study proposes that in a setting of obesity, dysregulated BCAA catabolism could be an effective surrogate to determine cardiac surgery outcomes and plausibly predict premature re-hospitalization.

IntroductionIncreasing levels of obesity worldwide have led to a rise in the prevalence of obesity-related complications including cardiovascular risk factors such as diabetes, hypertension and dyslipidaemia. Healthcare providers believe that overweight and obese cardiac surgery patients are more likely to experience adverse postoperative outcomes. The body mass index (BMI) is the primary measure of obesity in clinical practice, without accounting for a patient’s level of cardiopulmonary fitness or muscle mass. The objective of this study is to determine whether fitness capacity of obese cardiac surgical patients and biomarkers, alone or in combination, will help identify patients at risk for adverse outcomes when undergoing cardiac surgery.Methods and analysisPatients between the ages of 18 and 75 years undergoing elective cardiac surgery are consented to participate in this prospective observational study. Patients will be invited to participate in measures of obesity, functional capacity and exercise capacity assessments, quality of life questionnaires, and blood and tissue sampling for biomarker analysis. The endpoints evaluated are measures other than BMI that could be predictive of short-term and long-term postoperative outcomes. Clinical outcomes of interest are prolonged ventilation, hospital length of stay, renal failure and all-cause mortality. Biomarkers of interest will largely focus on metabolism (lipids, amino acids) and inflammation (adipokines, cytokines and chemokines).Ethics and disseminationThis study has been approved by the institutional review board at the Horizon Health Network. On completion of the study, the results shall be disseminated through conference presentations and publications in peer-reviewed journals. Additionally, the report shall also be diffused more broadly to the general public and the cardiovascular community.Trial registration numberNCT03248921.

Background Lysophosphatidic acid (LPA) receptor signaling has been implicated in cardiovascular and obesity-related metabolic disease. However, the distribution and regulation of LPA receptors in the myocardium and adipose tissue remain unclear. Objectives This study aimed to characterize the mRNA expression of LPA receptors (LPA1-6) in the murine and human myocardium and adipose tissue, and its regulation in response to obesity. Methods LPA receptor mRNA levels were determined by qPCR in i) heart ventricles, isolated cardiomyocytes, and perigonadal adipose tissue from chow or high fat-high sucrose (HFHS)-fed male C57BL/6 mice, ii) 3T3-L1 adipocytes and HL-1 cardiomyocytes under conditions mimicking gluco/lipotoxicity, and iii) human atrial and subcutaneous adipose tissue from non-obese, pre-obese, and obese cardiac surgery patients. Results LPA1-6 were expressed in myocardium and white adipose tissue from mice and humans, except for LPA3, which was undetectable in murine adipocytes and human adipose tissue. Obesity was associated with increased LPA4, LPA5 and/or LPA6 levels in mice ventricles and cardiomyocytes, HL-1 cells exposed to high palmitate, and human atrial tissue. LPA4 and LPA5 mRNA levels in human atrial tissue correlated with measures of obesity. LPA5 mRNA levels were increased in HFHS-fed mice and insulin resistant adipocytes, yet were reduced in adipose tissue from obese patients. LPA4, LPA5, and LPA6 mRNA levels in human adipose tissue were negatively associated with measures of obesity and cardiac surgery outcomes. This study suggests that obesity leads to marked changes in LPA receptor expression in the murine and human heart and white adipose tissue that may alter LPA receptor signaling during obesity.

Evidence regarding the safety and efficacy of intraoperative cell salvage (ICS) in transfusion reduction during cardiac surgery remains conflicting. We sought to evaluate the impact of routine ICS on outcomes following cardiac surgery.We conducted a retrospective analysis of patients who underwent nonemergent, first-time cardiac surgery 18 months before and 18 months after the implementation of routine ICS. Perioperative transfusion rates, postoperative bleeding, clinical and hematological outcomes, and overall cost were examined. We used multivariable logistic regression modelling to determine the risk-adjusted effect of ICS on likelihood of perioperative transfusion.A total of 389 patients formed the final study population (186 undergoing ICS and 203 controls). Patients undergoing ICS had significantly lower perioperative transfusion rates of packed red blood cells (pRBCs; 33.9% v. 45.3% p = 0.021), coagulation products (16.7% v. 32.5% p0.001) and any blood product (38.2% v. 52.7%, p = 0.004). Patients receiving ICS had decreased mediastinal drainage at 12 h (mean 320 [range 230-550] mL v. mean 400 [range 260-690] mL, p = 0.011) and increased postoperative hemoglobin (mean 104.7 ± 13.2 g/L v. 95.0 ± 11.9 g/L, p0.001). Following adjustment for other baseline and intraoperative covariates, ICS emerged as an independent predictor of lower perioperative transfusion rates of pRBCs (odds ratio [OR] 0.52, 95% confidence interval [CI] 0.31-0.87), coagulation products (OR 0.41, 95% CI 0.24-0.71) and any blood product (OR 0.47, 95% CI 0.29-0.77). Additionally, ICS was associated with a cost benefit of $116 per patient.Intraoperative cell salvage could represent a clinically cost-effective way of reducing transfusion rates in patients undergoing cardiac surgery. Further research on systematic ICS is required before recommending it for routine use.Les résultats d'études portant sur l'innocuité et l'efficacité de l'autotransfusion peropératoire (ATPO) comme mesure de réduction du besoin de transfusion durant une chirurgie cardiaque sont contradictoires. Nous avons cherché à évaluer l'incidence du recours systématique à l'ATPO sur les issues de chirurgies cardiaques.Nous avons mené une analyse rétrospective portant sur des patients ayant subi une première chirurgie cardiaque non urgente 18 mois avant et 18 mois après l'introduction de l'ATPO systématique. Les taux de transfusion périopératoire et d'hémorragie postopératoire, les résultats cliniques et hématologiques et le coût total ont été analysés. Nous avons utilisé un modèle de régression logistique multivariée pour déterminer l'incidence ajustée en fonction du risque du recours à l'ATPO sur la probabilité qu'une transfusion périopératoire soit nécessaire.L'échantillon à l'étude était composé de 389 patients (186 dans le groupe ATPO et 203 dans le groupe témoin). Par rapport au groupe témoin, les patients ayant reçu une ATPO ont eu besoin significativement moins souvent d'une transfusion de concentrés de globules rouges (33,9 % c. 45,3 %;L'autotransfusion peropératoire pourrait constituer un moyen cliniquement efficace en fonction des coûts de réduire les taux de transfusion des patients subissant une chirurgie cardiaque. D'autres recherches sur le recours systématique à l'ATPO devront être menées avant qu'on puisse recommander son utilisation de routine.

Background: Hemisternotomy has been suggested as a way to reduce morbidity by limiting the invasiveness of surgical interventions but it is often limited to aortic valve disease. This study reviews the experience of one center employing hemisternotomy and compares patient outcomes, both in-hospital and post-discharge, with a matched group of full sternotomy patients. Methods: Propensity scores were used to match all hemisternotomy valve cases (Hemi) to full sternotomy valve cases (Full) (1:2). An in-hospital composite outcome (COMP) was defined as mortality, stroke, deep sternal wound infection, sepsis, or return to operating room (OR) for bleeding or valve dysfunction. Provincial administrative health databases were used to determine freedom from mortality and hospital readmission for cardiac cause. Results: During the study period, 70 patients received hemisternotomy for various cardiac surgical interventions with only 38 patients undergoing isolated aortic valve replacement. Examining valve surgery exclusively, 65 Hemi were matched to 130 Full. In-hospital complications were low in both groups, with 1.0% mortality and a non-significant trend toward COMP in the Full group (Hemi = 4.6%; Full = 8.5%; p = 0.39). Ventilation time was significantly decreased in Hemi (median four vs. six hours; p = 0.002). At two years follow-up, survival was excellent for both (Hemi = 95.0%; Full = 93.6%) and freedom from cardiac morbidity (Hemi = 76.8%, Full = 73.2%) was comparable. Conclusion: Hemisternotomy appears to be a safe, effective, and versatile alternative for many cardiac surgical interventions. With a median follow-up of four years, this study represents the longest cardiac morbidity follow-up for hemisternotomy patients. However, we were unable to conclusively show a morbidity benefit with this incision.

Rates of perioperative transfusion vary widely among patients undergoing cardiac surgery. Few studies have examined factors beyond the clinical characteristics of the patients that may be responsible for such variation. The purpose of this study was to determine whether differing practice patterns had an impact on variation in perioperative transfusion at a single center.Patients who underwent cardiac surgery at a single center between 2004 and 2011 were considered. Comparisons were made between patients who had received a perioperative transfusion and those who had not from the clinical factors at baseline, intraoperative variables, and differing practice patterns, as defined by the surgeon, anesthesiologist, perfusionist, and the year in which the procedure was performed. The risk-adjusted effect of these factors on perioperative transfusion rates was determined using multivariable regression modeling techniques.The study population comprised 4823 patients, of whom 1929 (40.0%) received a perioperative transfusion. Significant variation in perioperative transfusion rates was noted between surgeons (from 32.4% to 51.5%, P .0001), anesthesiologists (from 34.4% to 51.9%, P .0001) and across year (from 28.2% in 2004 to 48.8% in 2008, P .0001). After adjustment for baseline and intraoperative variables, surgeon, anesthesiologist, and year of procedure were each found to be independent predictors of perioperative transfusion.Differing practice patterns contribute to significant variation in rates of perioperative transfusion within a single center. Strategies aimed at reducing overall transfusion rates must take into account such variability in practice patterns and account for nonclinical factors as well as known clinical predictors of blood transfusions.

s S231 groups that was of significance. In terms of survival, there were significant differences between the 35. 345 READMISSION RATES AND DIAGNOSES FOR PROLONGED INTENSIVE UNIT CARE STAY SURVIVORS FOLLOWING CARDIAC SURGERY RA Manji, BM Hiebert, RC Arora, MC Moon, DH Freed, AH Menkis

status postoperatively (odds ratio 2.6 1.3 per increasing MR grade; P 0.07). CONCLUSION: After mitral valve repair for ischemic MR, persistent or recurrent MR of mild to moderate degree appears associated with functional compromise. This finding carries implications with regards to the ongoing controversy of repair versus replacement for ischemic MR, and for new percutaneous mitral therapies which may not eradicate MR.