Adult Cardiac Surgical Population Research Articles

Accurate protamine:heparin matching (not just smaller protamine doses) decreases postoperative bleeding in cardiac surgery; results from a high-volume academic medical center.

A multidisciplinary Quality Assurance/Performance Improvement study to identify the incidence of "heparin rebound" in our adult cardiac surgical population instead detected a thromboelastometry pattern suggestive of initial protamine overdose in 34% despite Hepcon-guided anticoagulation management. Analysis of our practice led to an intervention that made an additional lower-range Hepcon cartridge available to the perfusionists. One year later, an IRB-approved retrospective study was conducted in >500 patients to analyze the effects of the intervention, specifically focusing on the impact of the initial protamine dose accuracy and 18-h mediastinal chest tube drainage (MCTd). No differences were observed between group demographics, surgical procedures, duration of CPB or perioperative blood product transfusion. Both groups were managed using the same perfusion and anesthesia equipment, strategies, and protocols. The median initial protamine dose decreased by 19% (p < .001) in the intervention group (170 [IQR 140-220] mg; n = 295) versus the control group (210 [180-250] mg; n = 257). Mean 18-h MCTd decreased by 13% (p < .001) in the intervention group (405.15 ± 231.54mL; n = 295) versus the control group (466.13 ± 286.73mL; n = 257). Covariate-adjusted mixed effects model showed a significant reduction of MCTd in the intervention group, starting from hour 11 after surgery (group by time interaction p = .002). Though previous investigators have associated lower protamine doses with less MCTd, this study demonstrates that more accurately matching the initial protamine dose to the remaining circulating heparin concentration reduces postoperative bleeding.

Albumin in adult cardiac surgery: a narrative review.

Intravascular fluids are a necessary and universal component of cardiac surgical patient care. Both crystalloids and colloids are used to maintain or restore circulating plasma volume and ensure adequate organ perfusion. In Canada, human albumin solution (5% or 25% concentration) is a colloid commonly used for this purpose. In this narrative review, we discuss albumin supply in Canada, explore the perceived advantages of albumin, and describe the clinical literature supporting and refuting albumin use over other fluids in the adult cardiac surgical population. We conducted a targeted search of PubMed, Embase, Medline, Web of Science, ProQuest Dissertations and Theses Global, the Cochrane Central Register of Controlled trials, and the Cochrane Database of Systematic Reviews. Search terms included albumin, colloid, cardiac surgery, bleeding, hemorrhage, transfusion, and cardiopulmonary bypass. Albumin is produced from fractionated human plasma and imported into Canada from international suppliers at a cost of approximately$21 million CAD per annum. While it is widely used in cardiac surgical patients across the country, it is approximately 30-times more expensive than equivalent doses of balanced crystalloid solutions, with wide inter-institutional variability in use and no clear association with improved outcomes. There is a general lack of high-quality evidence for the superiority of albumin over crystalloids in this patient population, and conflicting evidence regarding safety. In cardiac surgical patients, albumin is widely utilized despite a lack of high- quality evidence supporting its efficacy or safety. A well-designed randomized controlled trial is needed to clarify the role of albumin in cardiac surgical patients.

Intraoperative Mechanical Ventilation and Postoperative Pulmonary Complications after Cardiac Surgery.

Compared with historic ventilation strategies, modern lung-protective ventilation includes lower tidal volumes (VT), lower driving pressures, and application of positive end-expiratory pressure (PEEP). The contributions of each component to an overall intraoperative protective ventilation strategy aimed at reducing postoperative pulmonary complications have neither been adequately resolved, nor comprehensively evaluated within an adult cardiac surgical population. The authors hypothesized that a bundled intraoperative protective ventilation strategy was independently associated with decreased odds of pulmonary complications after cardiac surgery. In this observational cohort study, the authors reviewed nonemergent cardiac surgical procedures using cardiopulmonary bypass at a tertiary care academic medical center from 2006 to 2017. The authors tested associations between bundled or component intraoperative protective ventilation strategies (VT below 8 ml/kg ideal body weight, modified driving pressure [peak inspiratory pressure - PEEP] below 16 cm H2O, and PEEP greater than or equal to 5 cm H2O) and postoperative outcomes, adjusting for previously identified risk factors. The primary outcome was a composite pulmonary complication; secondary outcomes included individual pulmonary complications, postoperative mortality, as well as durations of mechanical ventilation, intensive care unit stay, and hospital stay. Among 4,694 cases reviewed, 513 (10.9%) experienced pulmonary complications. After adjustment, an intraoperative lung-protective ventilation bundle was associated with decreased pulmonary complications (adjusted odds ratio, 0.56; 95% CI, 0.42-0.75). Via a sensitivity analysis, modified driving pressure below 16 cm H2O was independently associated with decreased pulmonary complications (adjusted odds ratio, 0.51; 95% CI, 0.39-0.66), but VT below 8 ml/kg and PEEP greater than or equal to 5 cm H2O were not. The authors identified an intraoperative lung-protective ventilation bundle as independently associated with pulmonary complications after cardiac surgery. The findings offer insight into components of protective ventilation associated with adverse outcomes and may serve as targets for future prospective interventional studies investigating the impact of specific protective ventilation strategies on postoperative outcomes after cardiac surgery.

Clinical performances of EuroSCORE II risk stratification model in Serbian cardiac surgical population: A single centre validation study including 10,048 patients

Background/Aim. The EuroSCORE II has recently been developed with an idea to provide better accuracy in prediction of perioperative mortality in the patients who underwent open heart surgery. The aim of this study was to validate clinical performances of the European System for Cardiac Operative Risk Evaluation (EuroSCORE) II risk stratification model in the Serbian adult cardiac surgical population undergoing open heart surgery. Methods. The Euro- SCORE II values on 10,048 consecutive patients undergoing major adult cardiac surgery from 1st January 2012 to 31st March 2017, were prospectively calculated and entered the institutional database. The discriminative power of the model was tested by calculating the area under the receiver operating characteristic curve (AUC). The calibration of the model was assessed by the Hosmer-Lemeshow (H-L) statistics and the observed to expected (O/E) mortality ratio. The patients with the EuroSCORE II values of 0.5?2.50%, &gt; 2.50?6.50%), and &gt; 6.50% were defined to be at low, moderate, and high perioperative risk, respectively. Results. The observed in-hospital mortality was 3.86% (388 of 10,048) and the mean predicted mortality by the Euro- SCORE II was 3.61%. The discriminatory power was very good for the entire cohort as well as for all subgroups [coronary, valve(s), combined (coronary plus valve), aortic and other] of performed cardiac procedures (all AUCs &gt; 0.75). The H-L test confirmed good calibration only for category other cardiac procedures. The O/E mortality ratio confirmed good calibration for the whole sample [O/E ratio 1.07, 95% confidence interval (CI) 0.96?1.18] and for all subgroups of performed cardiac procedures, excluding significant underprediction of mortality for aortic surgery (O/E ratio 1.64; 95% CI 1.31?1.97). The EuroSCORE II overestimated perioperative risk in a low and underestimated perioperative risk in a high risk group, with acceptable discrimination (both AUCs = 0.72). On the contrary, the O/E mortality ratio confirmed good calibration for all three subcategories of high risk group. Conclusion. The results of our study confirmed acceptable overall performances of the EuroSCORE II risk stratification model in terms of discrimination and the accuracy of model when applied to the contemporary Serbian cardiac surgical cohort undergoing open heart surgery at our Institute.

Cerebrovascular autoregulation monitoring and patient-centred outcomes after cardiac surgery: a systematic review.

Impaired cerebrovascular autoregulation (CVAR) is observed in up to 20% of cardiac surgical patients. This systematic review aims to evaluate the association between impaired CVAR, measured by current monitoring techniques, and patient-centred outcomes in adults following cardiac surgery. MEDLINE, EMBASE, PubMed, MEDLINE In-Process and Cochrane Library were systematically searched through 8 December 2017. Studies were included if they assessed associations between CVAR and patient-centred outcomes in the adult cardiac surgical population. The primary outcome of this systematic review was mortality. Secondary outcomes were stroke, delirium and acute kidney injury. Risk of bias was systematically assessed, and the GRADE methodology was used to evaluate the quality of evidence across outcomes. Eleven observational studies and no randomised controlled trials met the inclusion criteria. Due to methodological heterogeneity, meta-analysis was not possible. There was a high risk of bias within individual studies and low quality of evidence across outcomes. Of the included studies, one assessed mortality, five assessed stroke, four assessed delirium, and three assessed acute kidney injury. No reliable conclusions can be drawn from the one study assessing mortality. Interpretation of studies investigating CVAR and stroke, delirium and acute kidney injury was complicated by the lack of standardisation of monitoring techniques as well as varying definitions of impaired CVAR. There is a paucity of high quality evidence for CVAR monitoring and its associations with outcome measures in post-cardiac surgical patients, highlighting the need for future studies.

EARLY EXPERIENCE WITH DEL NIDO CARDIOPLEGIA IN MINIMALLY INVASIVE CARDIAC SURGERY

Del Nido cardioplegia (DNC) has been used in the paediatric population since the early 1990s, achieving adequate myocardial protection. In addition, initial investigations in adults have demonstrated reduced myocardial damage and improved functional recovery post-operatively. As the utiilization of minimally invasive cardiac surgery is increasing as an alternative to traditional sternotomy, application of a cardioplegia solution that could provide myocardial protection for a long period of time would be ideal given the limited working space available and longer cross-clamp time during minimally invasive procedures. Our objective was to describe our experience with DNC as a primary myocardial protection strategy in adult cardiac patients undergoing minimally invasive surgery. We performed a restrospective review of all patients from September 2016 to April 2017 that underwent minimally invasive aortic or mitral valve surgery utilizing DNC as myocardial protection strategy delivered using the microplegia system (Quest medical, Dallas, Tx ). During the study period, 10 patients underwent elective cardiac surgery with DNC. Mean [SD] age was 59.8 [11.5] years, and 4 (40%) patients were female. Isolated aortic valve replacement (AVR) was performed in 2 patients (20%), and mitral valve repair (MVR) in 8 patients (80%, 1 using robot assistance. Mean [SD] crossclamp time and bypass times were 127 [23.4] and 217 [38.4] minutes, respectively (Table 1). Seven patients only required single dose of cardioplegia, while 3 required the dose to be repeated once. Four (40%) patients required to be on inotropic support postoperatively. There was no post-operative mortality, myocardial infarction, reintervention, reoperation for bleeding or renal failure requiring dialysis. Median [IQR] intensive care and hospital lengths of stay were 2 [1,3] days and 7 [6,8] days, respectively (Table 1). DNC is becoming increasingly utilized in the adult cardiac surgical population given its efficacy and cost-effectiveness in the paediatric population. Our experience suggests DNC is safe in minimally invasive cardiac surgery. It facilitates the conduct of minimally invasive cardiac surgery by reducing the number of applications of cardioplegia. This will facilitate the conduct of minimally invasive cardiac surgery and possibly benefit high risk patients by providing excellent myocardial protection. Randomized studies are needed to further evaluate its efficacy in adult cardiac surgery undergoing minimally invasive surgery.

Veno-Arterial ECMO in the Setting of Post-Infarct Ventricular Septal Defect: A Bridge to Surgical Repair.

Extracorporeal membrane oxygenation (ECMO) is a complex rescue therapy utilised to provide circulatory and/or respiratory support to critically ill patients who have failed maximal conventional therapy. The use of ECMO in adult cardiac surgery is not routine, occurring in a minority of critically ill patients, typically postoperatively. Presented here are three cases of post-infarct ventricular septal defect with cardiogenic shock managed preoperatively with ECMO support as a bridge to definitive surgical closure. We present a review of ECMO in the adult cardiac surgical population and highlight the potential role of preoperative ECMO for cardiogenic shock in the setting of post-infarct ventricular septal defect (PI VSD) as a bridge to definitive closure.

Pulmonary Impedance and Pulmonary Doppler Trace in the Perioperative Period.

Pulmonary hypertension and associated vascular changes may frequently accompany left-sided heart disease in the adult cardiac surgical population. Perioperative assessment of right ventricular function using echocardiography is well established. In general, understanding the constraints upon which the right ventricle must work is mostly limited to invasive monitoring consisting of pulmonary artery pressures, cardiac output, and pulmonary vascular resistance. The latter 2 measurements assume constant (mean) flows and pressures. The systolic and diastolic pressures offer a limited understanding of the pulsatile constraints, which may become significant in disease. In normal physiology, pressure and flow waves display near-similar contours. When left atrial pressure and pulmonary vascular resistance are increased, changes in pulmonary arterial compliance will result in elevated impedance to right ventricular ejection. Pressure reflections, the result of strong reflectors, return more quickly in a noncompliant system. They augment pulmonary artery pressure causing a premature reduction in flow. As a result, pressure and flow waves will now be dissimilar. The impact of vascular changes on right ventricular ejection can be assessed using pulmonary artery Doppler spectral imaging. The normal flow velocity profile is rounded at its peak. Earlier peaks and premature reductions in flow will make it appear more triangular. In some cases, the flow pattern may appear notched. The measurement of acceleration time, the time from onset to peak flow velocity is an indicator of constraint to ejection; shortened times have been associated with increased pulmonary vascular resistance and pressure. Understanding the changes in the pulmonary arterial system in disease and the physics of the hemodynamic alterations are essential in interpreting pulmonary artery Doppler data. Analyzing pulmonary artery Doppler flow signals may assist in the evaluation of right ventricular function in patients with pulmonary vascular disease.

The EuroSCORE: are we contributing to its overprediction of mortality in cardiac surgery nowadays?

We read with great interest the article by Akar et al. [1] regarding validation of the EuroSCORE risk models in the Turkish adult cardiac surgical population. This manuscript is in agreement with previous reports [2–4] that additive and logistic EuroSCORE models overpredict mortality in cardiac surgery nowadays. However, in our opinion there are a few issues that should be clarified. The first one is a definition of mortality. The original EuroSCORE model [5] defined operative mortality as death within 30 days from operation or even later than 30 days if still in hospital (not 30-day mortality as the authors stated in Discussion section of their manuscript [1]). On the other side, their calculation and statistical observations were based only on in-hospital mortality. It is possible that, with the inclusion of all patients who should be included as perioperative deaths (30-day mortality plus in-hospital mortality), the findings of the study [1] would no longer be statistically significant. When we validate a risk stratification model on a population out of its original database, we have to check its discriminatory power and calibration. Model discrimination was analysed by determining the area under the receiver operating characteristic (ROC) curve [1– 5]. However, several statistical procedures have been used to determine calibration. The Hosmer–Lemeshow (H-L) test has been used in >90% of all manuscripts to test the EuroSCORE calibration in different patient population (the H–L test confirms good calibration if the P-value is >0.05), including the EuroSCORE working group [5]. In a few manuscripts calibration plots, unpaired t-test [1], chisquare test [4] or observed to expected (O/E) ratios were used to prove that calibration of the EuroSCORE models was inadequate. Thus, we are curious as to what would be the results of the EuroSCORE calibration checking in these articles if the H–L test was used. On the contrary, Yap et al. [2] wrote an excellent manuscript with intention of validating the EuroSCORE model in Australia. Mortality definition was correct (in-hospital mortality plus 30-day mortality), areas under the ROC curves (0.82) confirmed an excellent discrimination for both additive and logistic EuroSCORE models, but calibration using the H–L test was poor (P 0.05) of the logistic EuroSCORE model. Finally, our question is—should we use the H–L test any more, or we are looking for a statistical procedure that will confirm poor calibration of the EuroSCORE models?

Validation of the EuroSCORE risk models in Turkish adult cardiac surgical population☆☆☆

The aim of this study was to validate additive and logistic European System for Cardiac Operative Risk Evaluation (EuroSCORE) models on Turkish adult cardiac surgical population. TurkoSCORE project involves a reliable web-based database to build up Turkish risk stratification models. Current patient population consisted of 9443 adult patients who underwent cardiac surgery between 2005 and 2010. However, the additive and logistic EuroSCORE models were applied to only 8018 patients whose EuroSCORE determinants were complete. Observed and predicted mortalities were compared for low-, medium-, and high-risk groups. The mean patient age was 59.5 years (± 12.1 years) at the time of surgery, and 28.6% were female. There were significant differences (all p<0.001) in the prevalence of recent myocardial infarction (23.5% vs 9.7%), moderate left ventricular function (29.9% vs 25.6%), unstable angina (9.8% vs 8.0%), chronic pulmonary disease (13.4% vs 3.9%), active endocarditis (3.2% vs 1.1%), critical preoperative state (9.0% vs 4.1%), surgery on thoracic aorta (3.7% vs 2.4%), extracardiac arteriopathy (8.6% vs 11.3%), previous cardiac surgery (4.1% vs 7.3%), and other than isolated coronary artery bypass graft (CABG; 23.0% vs 36.4%) between Turkish and European cardiac surgical populations, respectively. For the entire cohort, actual hospital mortality was 1.96% (n=157; 95% confidence interval (CI), 1.70-2.32). However, additive predicted mortality was 2.98% (p<0.001 vs observed; 95%CI, 2.90-3.00), and logistic predicted mortality was 3.17% (p<0.001 vs observed; 95%CI, 3.03-3.21). The predictive performance of EuroSCORE models for the entire cohort was fair with 0.757 (95%CI, 0.717-0.797) AUC value (area under the receiver operating characteristic, AUC) for additive EuroSCORE, and 0.760 (95%CI, 0.721-0.800) AUC value for logistic EuroSCORE. Observed hospital mortality for isolated CABG was 1.23% (n=75; 95%CI, 0.95-1.51) while additive and logistic predicted mortalities were 2.87% (95%CI, 2.82-2.93) and 2.89% (95%CI, 2.80-2.98), respectively. AUC values for the isolated CABG subset were 0.768 (95%CI, 0.707-0.830) and 0.766 (95%CI, 0.705-0.828) for additive and logistic EuroSCORE models. The original EuroSCORE risk models overestimated mortality at all risk subgroups in Turkish population. Remodeling strategies for EuroSCORE or creation of a new model is warranted for future studies in Turkey.

Biomarkers of Acute Kidney Injury

ESPITE more than half a century of investigation,acute kidney injury (AKI) remains a major healthcareissue in medicine today. Reported to occur in 1–32% of allhospital admissions and 10–90% of intensive care unit ad-missions, the wide variation reflects different criteria used todefineAKI.However,independentofdefinition,adiagnosisof AKI is consistently associated with an increase in bothshort- and long-term morbidity and mortality. Even themildest forms of AKI are independently associated with in-creased early as well as long-term mortality, the risk increas-ing as severity of renal injury increases.

Invited Commentary

This article is a descriptive observation study that attempted to determine if glucose level was associated with adverse outcome in a population of 144 pediatric cardiac surgical patients [1DeCampli W.M. Olsen M.C. Munro H.M. Felix D.E. Perioperative hyperglycemia: effect on outcome after infant congenital heart surgery.Ann Thorac Surg. 2010; 89: 181-186Abstract Full Text Full Text PDF PubMed Scopus (17) Google Scholar]. In the final version and analysis of this study, glucose was treated as a continuous variable, and in fact, no level of glucose predicted an increased risk for the primary composite mortality and infection end point (MORTINF). Only prebypass glucose, risk adjustment for congenital heart surgery (RACHS-1) level, and being a neonate predicted increased length of stay. The authors conclude that hyperglycemia occurs commonly after infant cardiac surgery and that hyperglycemia was not associated with adverse outcome. Interestingly, in no patient did serum glucose level rise above 200 mg/dL in the study period, which contrasts with other reports in which perioperative glucose often rises above 200 mg/dL. Glucose levels were somewhat arbitrarily selected throughout the postoperative period as the “last glucose day 1 and 2.” In fact, the significance of the “postbypass glucose level” is questionable because continuous ultrafiltration was used throughout the bypass period and the ultrafiltration process removes glucose. The study was not appropriately powered for mortality as a primary end point, so the authors chose to combine mortality and infections as a composite end point. This choice appears to be based on the assumption that hyperglycemia may be associated with increased risk of perioperative infection. Although this association seems reasonably sound in the adult cardiac surgical population, there is no definitive support for this in the pediatric cardiac surgical population. This association has not been clearly determined in existing literature, and the MORTINF composite outcome has not been validated in previous studies. It has recently been shown that occurrence of hyperglycemia in adult cardiac surgical patients is not benign. Several studies have shown that tight glycemic control in the perioperative period decreases mortality after cardiac procedures and reduces the incidence of postoperative adverse events, including infectious complications (pneumonia and mediastinitis), myocardial complications (low cardiac output, atrial fibrillation, recurrent ischemia), and prolonged mechanical ventilation and intensive care unit length of stay. The evidence for benefit of tight glycemic control in the pediatric cardiac surgical population is both insufficient and conflicting. A recent article by Ballweg and colleagues [2Ballweg J.A. Wernovsky G. Ittenbach R.F. et al.Hyperglycemia after infant cardiac surgery does not adversely impact neurodevelopmental outcome.Ann Thorac Surg. 2007; 84: 2052-2058Abstract Full Text Full Text PDF PubMed Scopus (46) Google Scholar] suggests that hyperglycemia after cardiopulmonary bypass did not result in increased risk of neurologic injury. In another study [3Polito A. Thiagarajan R.R. Laussen P.C. et al.Association between intraoperative an early postoperative glucose levels and adverse outcomes after complex congenital heart surgery.Circulation. 2008; 118: 2235-2242Crossref PubMed Scopus (71) Google Scholar], the greater the duration of hyperglycemia (glucose > 126 mg/dL) was associated with longer duration of hospitalization. More recently, a randomized prospective trial of aggressive glycemic control with insulin was done in a pediatric intensive care population that included 75% pediatric cardiac surgical patients. In this study of 700 patients, intensive glucose control resulted in decreased intensive care unit lengths of stay, lower lactate, decreased risk of infection, decreased inflammatory response as measured by C-reactive protein, and increased hypoglycemia. Importantly, this trial did not demonstrate an increased risk of neurologic injury with hypoglycemia or tighter glucose control [4Vlasselaers D. Milants I. Desmets L. et al.Intensive insulin therapy for patients in pediatric intensive care: a prospective randomized controlled study.Lancet. 2009; 373: 547-556Abstract Full Text Full Text PDF PubMed Scopus (440) Google Scholar]. This study by DeCampli and colleagues [1DeCampli W.M. Olsen M.C. Munro H.M. Felix D.E. Perioperative hyperglycemia: effect on outcome after infant congenital heart surgery.Ann Thorac Surg. 2010; 89: 181-186Abstract Full Text Full Text PDF PubMed Scopus (17) Google Scholar] adds to the debate regarding the benefit of glucose control in the pediatric cardiac surgical patient. But this question will best be resolved with well-designed randomized trials that have enough power to determine the potential risks or benefits of glycemic control. Perioperative Hyperglycemia: Effect on Outcome After Infant Congenital Heart SurgeryThe Annals of Thoracic SurgeryVol. 89Issue 1PreviewStudies demonstrate that cardiopulmonary bypass (CPB) causes intraoperative and postoperative hyperglycemia. Hyperglycemia has been associated with morbidity and mortality after infant cardiac surgery. We studied the effects on early postoperative outcomes of glucose (GLU) changes during and after pediatric cardiac surgery. Full-Text PDF