Effect of a national guideline on postoperative troponin surveillance: a retrospective cohort study.

PURPOSE: We aimed to evaluate the effect of the 2017 Canadian Cardiovascular Society (CCS) guidelines on troponin surveillance after noncardiac surgery. METHODS: This was a single-centre, retrospective, observational study. Patients aged 40 yr or older undergoing intermediate- to high-risk elective noncardiac surgery between 2016 and 2021 were included. We compared the number and percentage of troponin tests ordered before and after the guidelines were published and compared patient characteristics, specifically cardiovascular comorbidity, using odds ratio's (OR) with 95% confidence intervals (CIs). Outcomes were myocardial injury, myocardial infarction (MI), and in-hospital mortality. RESULTS: The cohort included 36,386 patients and the median age was 63 yr. Between 2016 and 2018, troponin surveillance was done in 2,461 (13%) of the 19,046 patients, compared with 2,398 (14%) of the 17,340 patients who had surgery between 2019 and 2021 (OR, 1.08; 95% CI, 1.02 to 1.15). Patients who had surgery in the second period had less cardiovascular comorbidity; the adjusted OR for troponin surveillance was 1.14 (95% CI, 1.07 to 1.21). In the two periods, troponin was elevated in 561 (2.9%) and 470 (2.7%) patients, an MI was documented in 54 (0.3%) and 36 (0.2%) patients, and 95 (0.5%) and 73 (0.4%) patients died, respectively. After adjustment for baseline differences in the two periods, the ORs for MI and mortality were 0.83 (95% CI, 0.54 to 1.27) and 0.88 (95% CI, 0.64 to 1.19), respectively. CONCLUSION: Although the odds of troponin ordering were slightly but significantly higher after publication of the CCS guidelines, the odds for detecting an MI and for mortality did not change.

RéSUMé: OBJECTIF: Notre objectif était d'évaluer l'effet des lignes directrices 2017 de la Société canadienne de cardiologie (SCC) sur le monitorage de la troponine après une chirurgie non cardiaque. MéTHODE: Il s'agissait d'une étude observationnelle rétrospective monocentrique. Les patient·es âgé·es de 40 ans ou plus bénéficiant d'une chirurgie non cardiaque non urgente à risque intermédiaire à élevé entre 2016 et 2021 ont été inclus·es. Nous avons comparé le nombre et le pourcentage de tests de troponine prescrits avant et après la publication des lignes directrices et comparé les caractéristiques des patient·es, en particulier la comorbidité cardiovasculaire, en utilisant le rapport de cotes (RC) avec des intervalles de confiance (IC) à 95 %. Les critères d'évaluation comprenaient les lésions myocardiques, l'infarctus du myocarde (IM) et la mortalité hospitalière. RéSULTATS: La cohorte comprenait 36 386 personnes et l'âge médian était de 63 ans. Entre 2016 et 2018, le monitorage de la troponine a été réalisé chez 2461 (13 %) des 19 046 patient·es, contre 2398 (14 %) des 17 340 patient·es opéré·es entre 2019 et 2021 (RC, 1,08; IC 95%, 1,02 à 1,15). Les patient·es qui ont bénéficié d'une intervention chirurgicale au cours de la deuxième période présentaient moins de comorbidité cardiovasculaire; le RC ajusté pour le monitorage de la troponine était de 1,14 (IC 95 %, 1,07 à 1,21). Au cours des deux périodes, la troponine était élevée chez 561 (2,9 %) et 470 (2,7 %) patient·es, un IM a été documenté chez 54 (0,3 %) et 36 (0,2 %) patient·es, et 95 (0,5 %) et 73 (0,4 %) patient·es sont décédé·es, respectivement. Après ajustement pour tenir compte des différences initiales au cours des deux périodes, les RC pour l'IM et la mortalité étaient de 0,83 (IC 95 %, 0,54 à 1,27) et de 0,88 (IC 95 %, 0,64 à 1,19), respectivement. CONCLUSION: Bien que les probabilités de commande de troponine aient été légèrement mais significativement plus élevées après la publication des lignes directrices de la SCC, les probabilités de détection d'un IM et de mortalité n'ont pas changé.

Albumin use for fluid resuscitation in cardiac surgical patients: a survey of Canadian perioperative care providers.

PURPOSE: To evaluate the perceptions and practices of Canadian cardiovascular anesthesiologists and intensivists towards intravenous albumin as a resuscitation fluid in patients undergoing cardiac surgery. METHODS: We conducted a cross-sectional survey of cardiac anesthesiologists and intensivists involved in the care of cardiac surgical patients. The 22-item survey included seven open-ended questions and assessed practice patterns and attitudes towards albumin. Descriptive statistics were analyzed using counts and proportions. Qualitative data were analyzed to identify themes describing albumin use patterns in Canada. RESULTS: A total of 133 respondents from seven provinces participated, with 83 (62%) using albumin perioperatively. The majority of respondents (77%) felt a low fluid balance in cardiac surgical patients was important, and that supplementing crystalloids with albumin was helpful for this objective (67%). There was poor agreement among survey respondents regarding the role of albumin for faster vasopressor weaning or intensive care discharge, and ≥ 90% did not feel albumin reduced mortality, renal injury, or coagulopathy. Nevertheless, cardiac surgical patients were identified as a distinct population where albumin may help to minimize fluid balance. There was an acknowledged paucity of formal evidence supporting possible benefits. Fewer than 10% of respondents could identify institutional or national guidelines for albumin use. A lack of evidence supporting albumin use in cardiac surgical patients, especially those at highest risk of complications, was a frequently identified concern. CONCLUSIONS: The majority of Canadian anesthesiologists and intensivists (62%) use albumin in cardiac surgical patients. There is clinical equipoise regarding its utility, and an acknowledged need for higher quality evidence to guide practice.

RéSUMé: OBJECTIF: Évaluer les perceptions et les pratiques des anesthésiologistes et intensivistes cardiovasculaires canadiens à l'égard de l'albumine intraveineuse comme liquide de réanimation pour les patients bénéficiant d'une chirurgie cardiaque. MéTHODE: Nous avons mené un sondage transversal auprès d'anesthésiologistes et d'intensivistes cardiaques impliqués dans les soins aux patients de chirurgie cardiaque. Le sondage en 22 éléments comprenait sept questions ouvertes et évaluait les habitudes de pratique et les attitudes des praticiens à l'égard de l'albumine. Les statistiques descriptives ont été analysées à l'aide de dénombrements et de proportions. Des données qualitatives ont été analysées pour identifier des thèmes décrivant les tendances d'utilisation de l'albumine au Canada. RéSULTATS: Au total, 133 répondants de sept provinces ont participé, et 83 (62 %) utilisent l'albumine en périopératoire. La majorité des répondants (77 %) estimaient qu'un bilan liquidien négatif était important chez les patients en chirurgie cardiaque et que la supplémentation en cristalloïdes par de l'albumine était utile pour atteindre cet objectif (67 %). Il y avait un faible accord parmi les répondants concernant le rôle de l'albumine pour accélérer le sevrage des vasopresseurs ou la sortie de soins intensifs, et ≥ 90 % ne pensaient pas que l'albumine réduisait la mortalité, les lésions rénales ou la coagulopathie. Néanmoins, les patients en chirurgie cardiaque ont été identifiés comme une population distincte pour laquelle l'albumine pourrait contribuer à minimiser le bilan liquidien. Il y avait un manque reconnu de données probantes formelles à l'appui des avantages possibles. Moins de 10 % des répondants ont pu trouver des lignes directrices institutionnelles ou nationales portant sur l'utilisation de l'albumine. Le manque de données probantes à l'appui de l'utilisation de l'albumine chez les patients en chirurgie cardiaque, en particulier chez ceux présentant le risque le plus élevé de complications, était une préoccupation fréquemment identifiée. CONCLUSION: La majorité des anesthésiologistes et intensivistes canadiens (62 %) utilisent l'albumine chez les patients en chirurgie cardiaque. Il existe un équilibre clinique quant à son utilité et un besoin reconnu de données probantes de meilleure qualité pour guider la pratique.

Assessing the utility of an IoS application in the perioperative care of spine surgery patients: the NeuroPath Pilot study.

BACKGROUND: In an attempt to improve care while decreasing costs and postoperative pain, we developed a novel IoS mobile health application, NeuroPath. The objective of this innovative app is to integrate enhanced recovery after surgery (ERAS) principles, patient education, and real-time pain and activity monitoring in a home setting with unencumbered two-way communication. METHODS: The NeuroPath application was built over 18 months, with support from Apple, Medable, the Department of Information-Technology and the Department of Neurosurgery. Target areas addressed by NeuroPath include patient prep for surgery, perioperative risk mitigation, activity monitoring, wound care, and opioid use management. These target areas are monitored through a provider app, which is downloaded to the care providers IPad Mini. The provider app permits real time viewing of wound healing (patient incision photographs), activity levels, pain levels, and narcotic usage. Participants are given a daily To-Do list, via the Care Card section of the interface. The To-Do list presents the patient with specific tasks for exercise, instructions to wash incision area, pre-operative instructions, directions for discussing medication with care team, among other patient specific recommendations. RESULTS: Of the 30 patients enrolled in the pilot study, there was a range of activity on the app. Patients with high involvement in the app logged in nearly every day from a week pre-op to >45 days post-op. Data for patients that utilized the app and uploaded regularly show trends of appropriately healing wounds, decreasing levels of pain, increasing step counts, and discontinuation of narcotics. CONCLUSIONS: This pilot study of the NeuroPath app demonstrates its potential utility for improving quality of patient care without increased costs. Participants who regularly used the app showed consistent improvement throughout the post-operative recovery period (increasing ambulation, decreasing pain and guided reduction in narcotic usage).

Depicting surgical anatomy of the porta hepatis in living donor liver transplantation.

Visualizing the complex anatomy of vascular and biliary structures of the liver on a case-by-case basis has been challenging. A living donor liver transplant (LDLT) right hepatectomy case, with focus on the porta hepatis, was used to demonstrate an innovative method to visualize anatomy with the purpose of refining preoperative planning and teaching of complex surgical procedures. The production of an animation-enhanced video consisted of many stages including the integration of pre-surgical planning; case-specific footage and 3D models of the liver and associated vasculature, reconstructed from contrast-enhanced CTs. Reconstructions of the biliary system were modeled from intraoperative cholangiograms. The distribution of the donor portal veins, hepatic arteries and bile ducts was defined from the porta hepatis intrahepatically to the point of surgical division. Each step of the surgery was enhanced with 3D animation to provide sequential and seamless visualization from pre-surgical planning to outcome. Use of visualization techniques such as transparency and overlays allows viewers not only to see the operative field, but also the origin and course of segmental branches and their spatial relationships. This novel educational approach enables integrating case-based operative footage with advanced editing techniques for visualizing not only the surgical procedure, but also complex anatomy such as vascular and biliary structures. The surgical team has found this approach to be beneficial for preoperative planning and clinical teaching, especially for complex cases. Each animation-enhanced video case is posted to the open-access Toronto Video Atlas of Surgery (TVASurg), an education resource with a global clinical and patient user base. The novel educational system described in this paper enables integrating operative footage with 3D animation and cinematic editing techniques for seamless sequential organization from pre-surgical planning to outcome.

Visualising a rare and complex case of advanced hilar cholangiocarcinoma.

The Toronto Video Atlas of Liver, Pancreas, Biliary, and Transplant Surgery (TVASurg) is a free online library of three-dimensional (3D) animation-enhanced surgical videos, designed to instruct surgical fellows in hepato-pancreato-biliary (HPB) and transplant procedures. The video 'Klatskin tumours: Extended left hepatectomy with complex portal vein reconstruction and in situ cold perfusion of the liver', which is available to watch at http://TVASurg.ca , is a unique and valuable visual resource for surgeons in training to assist them in learning this rare procedure. This paper describes the methodologies used in producing this 3D animation-enhanced surgical video.

Creating an animation-enhanced video library of hepato-pancreato-biliary and transplantation surgical procedures.

The potential for integrating real-time surgical video and state-of-the art animation techniques has not been widely applied to surgical education. This paper describes the use of new technology for creating videos of liver, pancreas and transplant surgery, annotating them with 3D animations, resulting in a freely-accessible online resource: The Toronto Video Atlas of Liver, Pancreas and Transplant Surgery ( http://tvasurg.ca ). The atlas complements the teaching provided to trainees in the operating room, and the techniques described in this study can be readily adapted by other surgical training programmes.

Association of intraoperative hypotension with acute kidney injury after elective noncardiac surgery.

BACKGROUND: Intraoperative hypotension (IOH) may be associated with postoperative acute kidney injury (AKI), but the duration of hypotension for triggering harm is unclear. The authors investigated the association between varying periods of IOH with mean arterial pressure (MAP) less than 55, less than 60, and less than 65 mmHg with AKI. METHODS: The authors conducted a retrospective cohort study of 5,127 patients undergoing noncardiac surgery (2009 to 2012) with invasive MAP monitoring and length of stay of 1 or more days. Exclusion criteria were preoperative MAP less than 65 mmHg, dialysis dependence, urologic surgery, and surgical duration less than 30 min. The primary exposure was IOH. The primary outcome was AKI (50% or 0.3 mg/dl increase in creatinine) during the first 2 postoperative days. Multivariable logistic regression was used to model the exposure-outcome relationship. RESULTS: AKI occurred in 324 (6.3%) patients and was associated with MAP less than 60 mmHg for 11 to 20 min and MAP less than 55 mmHg for more than 10 min in a graded fashion. The adjusted odds ratio of AKI for MAP less than 55 mmHg was 2.34 (1.35 to 4.05) for 11- to 20-min exposure and 3.53 (1.51 to 8.25) for more than 20 min. For MAP less than 60 mmHg, the adjusted odds ratio for AKI was 1.84 (1.11 to 3.06) for 11- to 20-min exposure. CONCLUSIONS: In this analysis, postoperative AKI is associated with sustained intraoperative periods of MAP less than 55 and less than 60 mmHg. This study provides an impetus for clinical trials to determine whether interventions that promptly treat IOH and are tailored to individual patient physiology could help reduce the risk of AKI.

Use of preoperative antidepressants is not associated with postoperative hospital length of stay.

PURPOSE: Antidepressant medications are commonly prescribed for the treatment of depression, anxiety, and chronic pain. Their use may lead to a number of side effects with important implications in the perioperative period. Our aim was to examine the effect of preoperative antidepressant administration on post-surgical hospital length of stay (LOS) in elective non-cardiac surgery patients. DESIGN: Historical cohort study. METHODS: Demographic and preoperative data were collected by chart review for all non-cardiac surgery patients who were assessed in the preoperative consult clinic from April 2008 through February 2009. Patients were grouped according to whether or not they were taking antidepressant medications. Median length of stay was compared between patients who took antidepressants preoperatively and those who did not. RESULTS: Data were collected for 3,692 patients. Two hundred eighty-nine (7.8%) patients were taking antidepressants preoperatively. Use of antidepressants was not associated with an increased hospital LOS. The median LOS was four days both for patients who took antidepressants preoperatively (95% confidence interval [CI] 4 to 4) and for those who did not (95% CI 3 to 5) (P = 0.13). CONCLUSIONS: The preoperative use of antidepressant medications was not associated with increased postoperative hospital LOS following elective non-cardiac surgery.

The Revised Cardiac Risk Index in the new millennium: a single-centre prospective cohort re-evaluation of the original variables in 9,519 consecutive elective surgical patients.

PURPOSE: Cardiac complications following non-cardiac surgery are major causes of morbidity and mortality. The Revised Cardiac Risk Index (RCRI) has become a standard for predicting post-surgical cardiac complications. This study re-examined the original six risk factors to confirm their validity in a large modern prospective database. METHODS: Using the definitions in the original risk index, this study included 9,519 patients aged ≥ 50 undergoing elective non-cardiac surgery with an expected length of stay ≥ two days at two major tertiary-care teaching hospitals. The validity of the original predictors was tested in this population using binomial logistic regression modelling, area under the receiver operator curve (ROC) analysis, and the net reclassification index. RESULTS: Rates of major cardiac complications with 0, 1, 2, ≥ 3 of the predictors were 0.5%, 2.6%, 7.2%, and 14.4%, respectively, in our patient cohort compared with 0.4%, 1.1%, 4.6%, and 9.7%, respectively, in the original cohort. Similar to the original report, binary logistic regression analysis showed that both preoperative treatment with insulin (odds ratio [OR] 1.4; 95% confidence interval [CI] 0.7 to 2.6) and preoperative creatinine > 176.8 mmol·L(-1) (OR 1.7; 95% CI 0.8 to 3.6) did not improve the predictive ability of the index. Analysis of the remaining four factors resulted in an area under the curve (AUC) identical to that seen for the reconstructed six-factor RCRI (AUC = 0.79). We found that a glomerular filtration rate (GFR) < 30 mL·min(-1) was a better predictor of major cardiac complications (OR 2.2; 95% CI 1.2 to 4.3) than creatinine > 176.8 mmol·L(-1). The receiver operating characteristic analysis of this resultant 5-Factor model resulted in an AUC of 0.79, with 0, 1, 2, ≥ 3 of the predictors representing 0.5%, 2.9%, 7.4%, and 17.0% risk, respectively, among our patient cohort. CONCLUSION: Compared with the RCRI, a simplified 5-Factor model using a high-risk type of surgery, a history of ischemic heart disease, congestive heart failure, cerebrovascular disease, and a preoperative GFR < 30 mL·min(-1) results in superior prediction of major cardiac complications following elective non-cardiac surgery.

Selective ß1-antagonism with bisoprolol is associated with fewer postoperative strokes than atenolol or metoprolol: a single-center cohort study of 44,092 consecutive patients.

BACKGROUND: Perioperative metoprolol increases postoperative stroke. Animal studies indicate that the mechanism may be related to attenuated ß(2)-adrenoreceptor-mediated cerebral vasodilatation. The authors therefore conducted a cohort to study whether the highly ß(1)-specific ß-blocker (bisoprolol) was associated with a reduced risk of postoperative stroke compared with less selective ß-blockers (metoprolol or atenolol). METHODS: The authors conducted a single-center study on 44,092 consecutive patients with age 50 yr or more having noncardiac, nonneurologic surgery. The primary outcome was stroke within 7 days of surgery. The secondary outcome was a composite of all-cause mortality, postoperative myocardial injury, and stroke. A propensity score-matched cohort was created to assess the independent association between bisoprolol and less ß(1)-selective agents metoprolol or atenolol. A secondary analysis using logistic regression, based on previously identified confounders, also compared selective ß(1)-antagonism. RESULTS: Twenty-four percent (10,756) of patients were exposed to in-hospital ß-blockers. A total of 88 patients (0.2%) suffered a stroke within 7 days of surgery. The matched cohort consisted of 2,462 patients, and the pairs were well matched for all variables. Bisoprolol was associated with fewer postoperative strokes than the less selective agents (odds ratio = 0.20; 95% CI, 0.04-0.91). Multivariable risk-adjustment in the ß-blockers-exposed patients comparing bisoprolol with the less selective agents was associated with a similarly reduced stroke rate. CONCLUSIONS: The use of metoprolol and atenolol is associated with increased risks of postoperative stroke, compared with bisoprolol. These findings warrant confirmation in a pragmatic randomized trial.

Hyperchloremia after noncardiac surgery is independently associated with increased morbidity and mortality: a propensity-matched cohort study.

BACKGROUND: The use of normal saline is associated with hyperchloremic metabolic acidosis. In this study, we sought to determine the incidence of acute postoperative hyperchloremia (serum chloride >110 mEq/L) and whether this electrolyte disturbance is associated with an increase in length of hospital stay, morbidity, or 30-day postoperative mortality. METHODS: Data were retrospectively collected on consecutive adult patients (>18 years of age) who underwent inpatient, noncardiac, nontransplant surgery between January 1, 2003 and December 31, 2008. The impact of postoperative hyperchloremia on patient morbidity and length of hospital stay was examined using propensity-matched and logistic multivariable analysis. RESULTS: The dataset consisted of 22,851 surgical patients with normal preoperative serum chloride concentration and renal function. Acute postoperative hyperchloremia (serum chloride >110 mmol/L) is quite common, with an incidence of 22%. Patients were propensity-matched based on their likelihood to develop acute postoperative hyperchloremia. Of the 4955 patients with hyperchloremia after surgery, 4266 (85%) patients were matched to patients who had normal serum chloride levels after surgery. These 2 groups were well balanced with respect to all variables collected. The hyperchloremic group was at increased risk of mortality at 30 days postoperatively (3.0% vs 1.9%; odds ratio = 1.58; 95% confidence interval, 1.25-1.98) (relative risk 1.6 or risk increase of 1.1%) and had a longer hospital stay (7.0 days [interquartile range 4.1-12.3] compared with 6.3 [interquartile range 4.0-11.3]) than patients with normal postoperative serum chloride levels. Patients with postoperative hyperchloremia were more likely to have postoperative renal dysfunction. Using all preoperative variables and measured outcome variables in a logistic regression analysis, hyperchloremia remained an independent predictor of 30-day mortality with an odds ratio of 2.05 (95% confidence interval, 1.62-2.59). CONCLUSION: This retrospective cohort trial demonstrates an association between hyperchloremia and poor postoperative outcome. Additional studies are required to demonstrate a causal relationship between these variables.

The relationship between fibrinogen levels after cardiopulmonary bypass and large volume red cell transfusion in cardiac surgery: an observational study.

BACKGROUND: Coagulopathy leading to excessive blood loss and large volume red cell transfusion is a frequent complication of cardiac surgery with cardiopulmonary bypass (CPB) that may be caused by low perioperative fibrinogen levels. We explored the relationship between post-CPB fibrinogen levels and large volume red cell transfusion. METHODS: Patients who underwent cardiac surgery with CPB from 2005 to 2011 at a single institution and had a fibrinogen level measured after CPB were included in this retrospective observational study. The relationship between post-CPB fibrinogen levels and large volume red cell transfusion (defined as ≥5 units transfused on the day of or the day after surgery) was assessed by cubic spline function and receiver operating characteristic analyses. The independent relationship between fibrinogen levels and large volume transfusion was assessed by multivariable logistic regression and propensity score analyses. RESULTS: In the 4606 patients included, the probability of large volume transfusion increased when fibrinogen levels decreased below approximately 2.0 g/L. Using <2.0 g/L as the threshold for low fibrinogen, 1918 (42%) were categorized into the low fibrinogen group, of whom 363 (18.9%) had large volume transfusion compared with 164 (13.5%) of the 2688 patients whose fibrinogen level was ≥2.0 g/L (P < 0.0001). In the low fibrinogen group, the unadjusted odds ratio (95% confidence interval) for large volume transfusion was 1.5 (1.3-1.7). The risk-adjusted odds ratio obtained by logistic regression was 1.8 (1.4-2.2) and by propensity score methods was 1.5 (1.2-2.0). CONCLUSIONS: While this study was not equipped to detect the critical fibrinogen level in bleeding patients, its results suggest that current recommendations that fibrinogen replacement not be initiated in bleeding patients unless fibrinogen levels decrease below 0.8 to 1.0 g/L may be too conservative. Randomized trials are needed to determine whether maintaining higher fibrinogen levels in bleeding patients can reduce blood loss and transfusions and by that means improve clinical outcomes in cardiac surgery.

Use of clinically based troponin underestimates the cardiac injury in non-cardiac surgery: a single-centre cohort study in 51,701 consecutive patients.

PURPOSE: Postoperative myocardial infarction causes hundreds of thousands of deaths annually, and "failure to rescue" is a leading cause of hospital mortality. Strategies to recognize cardiac injury are important to reduce the burden of cardiac-related morbidity. For these reasons, we chose to assess the association between postoperative troponin I elevations and 30-day in-hospital mortality and, secondarily, to compare the predictive value of regularly scheduled troponin estimates with troponin ordered in response to clinical indications. METHODS: We carried out a retrospective cohort analysis of 51,701 consecutive patients throughout 2003 to 2009. All patients were from a single university referral hospital and included all non-cardiac non-transplant surgery patients requiring overnight admission. Logistic regression was used to assess the risk-adjusted associations between troponin I and 30-day in-hospital mortality. RESULTS: The multivariable predictive model for death improved after troponin I was included. The receiver operating characteristic was 0.902 before troponin I vs 0.934 after troponin I (P<0.0001). The likelihood ratio for troponin was 3.0 (95% confidence interval 2.8 to 3.2) and evident in each surgical service. Increasing troponin I showed a dose-response associated with increased mortality, and compared with clinically based measurements, a regularly scheduled postoperative troponin protocol showed a threefold increase in the probability of detecting myocardial injury. However, troponin I was not found to improve the risk prediction model in the lowest risk patients (n=18,953; probability of death<0.02%) with one cardiac death. CONCLUSIONS: Postoperatively elevated troponin I is associated with 30-day in-hospital mortality in a dose-dependent manner. A postoperative measurement protocol provides a threefold increase in the ability to detect myocardial injury. Conversely, in patients with a low mortality risk, cardiac injury is low; there is minimal improvement in the ability to detect cardiac injury, and the rescue rates from cardiac injury are excellent. These findings suggest that a surveillance protocol of troponin I would be optimal when limited to moderate to high-risk patients.

Gender differences in mortality following non-cardiovascular surgery: an observational study.

PURPOSE: Although inequality between males and females in cardiovascular surgery is well recognized, few studies have examined the influence of sex on mortality following non-cardiovascular surgery. The objective of the study was to determine whether there are differences in mortality between males and females following non-cardiovascular surgery and to ascertain to what extent preoperative risk factors explain these differences. METHODS: This was an observational study of 39,433 consecutive non-cardiovascular inpatient surgical cases from non-sex-biased surgical services from 2003 to 2009. Data on the surgical procedure, patient risk factors, and outcomes was retrieved from the institutional Electronic Data Warehouse. The primary outcome was in-hospital mortality within 30 days of surgery. Multivariate analysis using logistic regression was conducted to determine the role of risk factors for mortality. RESULTS: The 30-day mortality was 2.76% for males and 1.89% for females (odds ratio, 1.47; 95% confidence interval [CI], 1.29 to 1.69). Logistic regression showed that age, number of Charlson comorbidities, American Society of Anesthesiologists (ASA) classification, and emergent/urgent status were independent predictors of mortality (receiver operating characteristic area, 0.90). After adjustment for these factors, the odds ratio for male mortality was reduced to 1.31 (95% CI, 1.14 to 1.52). CONCLUSION: Males present for non-cardiovascular surgery with a higher ASA classification, with more comorbidities, and more often emergently than females, providing a partial explanation of the observed difference in mortality.

Chronic ß blockade is associated with a better outcome after elective noncardiac surgery than acute ß blockade: a single-center propensity-matched cohort study.

BACKGROUND: Current guidelines on perioperative care recommend the prophylactic use of ß blockers in high-risk patients undergoing noncardiac surgery. However, recent studies show that, in some instances, perioperative ß blockade can cause harm. Furthermore, chronic ß blockade, titrated to effect before surgery, may be superior to acute perioperative ß blockade. The primary objective of this study was to compare major acute cardiac outcomes in patients who underwent surgery with chronic ß blocker therapy with those in patients with acute ß-blocker therapy. METHODS: Data were collected for 10,691 consecutive patients undergoing elective noncardiac surgery between April 1, 2008, and April 30, 2010. Propensity scores, estimating the probability of receiving a preoperative ß blocker, were calculated to match (1:1) the patients with acute and chronic ß-blocker therapy. The primary outcome was a composite of myocardial infarction, nonfatal cardiac arrest, and perioperative mortality. The rate of cardiac events was compared in the matched cohorts. RESULTS: A total of 962 patients were chronically treated with a ß blocker before surgery; in 436 patients, the ß blocker was administrated acutely. Propensity score matching created 301 patient pairs who were well-balanced for major comorbidities, concomitant drug use, and type of surgery. The primary outcome was observed in 9 (3.0%) chronic versus 24 (8.0%) acute ß-blocked patients (relative risk, 2.67; 95% CI, 1.27-5.60; P = 0.011). CONCLUSIONS: Acute ß blockade, initiated within the first 2 days after surgery, was associated with worse cardiac outcome compared with a matched cohort of patients who underwent surgery on chronic ß blockade. These results should be validated in a larger prospective trial.

The safety of perioperative esmolol: a systematic review and meta-analysis of randomized controlled trials.

BACKGROUND: Although ß blockers have been found to decrease perioperative myocardial infarction (MI), ß-blocker-mediated hypotension is associated with postoperative stroke and mortality. In this systematic review we assessed the safety and efficacy of the ß1-specific, adrenergic receptor antagonist esmolol in noncardiac surgery. Safety was assessed by analyzing the incidence of postoperative hypotension and bradycardia, and efficacy was assessed by analyzing the incidence of myocardial ischemia. METHODS: We searched electronic databases for randomized placebo-controlled trials of the perioperative use of esmolol in noncardiac surgery. We abstracted data on design, demographics, hemodynamic changes (planned or unplanned), myocardial ischemia, and MI. Heterogeneity was assessed via meta-regression. RESULTS: Our search identified 67 trials, which were well matched for study characteristics. The quality of the studies was limited by small sample size and poorly defined allocation concealment. Overall, the analysis demonstrates an increased incidence of unplanned hypotension (OR 2.13; 95% confidence interval [CI], 1.48 to 3.04), which was found to be dose related (R(2) = 0.408). An increased incidence of significant bradycardia was not demonstrated (OR 1.18; 95% CI, 0.69 to 2.02). Dose titration was shown to influence both the change in arterial blood pressure and heart rate. In comparison with placebo, esmolol decreased the frequency of myocardial ischemia in the 7 evaluating studies (OR 0.17; 95% CI, 0.02 to 0.45). We did not assess the effects of esmolol on the incidence of MI or stroke because the incidence of these events was too infrequent in the retrieved studies. CONCLUSION: This review suggests that titration of esmolol to a hemodynamic end point can be safe and effective. Safety data from studies in higher-risk patients are needed to establish a perioperative safety and efficacy profile of esmolol.

An interactive online 3D model of the heart assists in learning standard transesophageal echocardiography views.

PURPOSE: Transesophageal echocardiography (TEE) is becoming a standard imaging tool during cardiac surgery as well as an important diagnostic tool in cardiology and in intensive care, resulting in an increasing demand for TEE training. To address the problem of limited time for learning during TEE studies, we have developed a novel online application that allows users to visualize each of the 20 standard diagnostic TEE views in conjunction with a three-dimensional (3D) heart model that can be rotated and "cut away" above the echo plane to reveal the internal cardiac structures. This study is an evaluation of the educational benefit of this application. METHODS: The application was evaluated using a pre-test/post-test design assessing the improvement of subjects' test scores following three days of access to the application. The subjects were postgraduate fellows in anesthesia, cardiology, and cardiac surgery. RESULTS: Ten subjects showed a significant increase (31%) in their test scores after an average of 130 min of access to the application over a three-day period (P < 0.001, effect size = 1.9). Using five-point Likert scales, the users indicated that the application was a useful addition to their training (4.7), they would recommend the application to their colleagues (4.9), and they found the application easy to use (4.4). CONCLUSION: The large improvement in test scores during a short period of study and the high level of satisfaction across all of the disciplines indicates that the application is a useful adjunctive tool for learning TEE. It is now being used in TEE training worldwide.

Hospital administrative database underestimates delirium rate after cardiac surgery.

PURPOSE: Administrative electronic databases are highly specific for postoperative complications, but they lack sensitivity. The objective of this study was to determine the incidence of delirium after cardiac surgery using a targeted prospectively collected dataset and to compare the findings with the incidence of delirium in the same cohort of patients identified in a hospital administrative database. METHODS: Following Research Ethics Board approval, we compared delirium rates in a prospectively collected data research database with delirium rates in the same cohort of patients in an administrative hospital database where delirium was identified from codes entered by coding and abstracting staff. Every 12 hr postoperatively, delirium was assessed with a Confusion Assessment Method in the Intensive Care Unit. The administrative database contained the International Classification of Diseases version 10 (ICD-10) codes for patient diagnoses. The ICD-10 codes were extracted from the administrative database for each patient in the research database and were checked for the presence of the ICD-10 code for delirium. RESULTS: Data from a cohort of 1,528 patients were analyzed. Postoperative delirium was identified in 182 (11.9%) patients (95% confidence interval [CI], 10.3-13.5%) in the research dataset and 46 (3%) patients (95% CI, 2.2-3.8%) in the administrative dataset (P < 0.001). Thirteen (0.85%) patients who were coded for delirium in the administrative database were not identified in the research dataset. The median onset of postoperative delirium in these patients was significantly delayed (4 [3-9] days) compared with patients identified by both datasets (2 [1-9] days) and compared with patients from the research database only (1 [1-14] days) (P = 0.007). CONCLUSION: Postoperative delirium rates after cardiac surgery are underestimated by the hospital administrative database.

The risk-benefit profile of aprotinin versus tranexamic acid in cardiac surgery.

BACKGROUND: Aprotinin is superior to other antifibrinolytic drugs for preventing major blood loss after cardiac surgery but may also increase perioperative mortality. It remains unclear whether its risk-benefit profile differs among low-, moderate-, and high-risk cardiac surgical patients. METHODS: In this retrospective single-center cohort study, we included 15,365 patients who underwent cardiac surgery with cardiopulmonary bypass from 2000 to 2008. Of these, 1017 received aprotinin (6 x 10(6) U) and 14,358 received tranexamic acid (50-100 mg/kg). Propensity score methods were used to create a matched-pairs cohort (n = 1544) that adjusted for important between-group differences. The influence of patients' risk status on aprotinin's association with in-hospital mortality, morbidity, and blood loss was measured. RESULTS: In the matched set, aprotinin was only associated with increased acute kidney injury (> 50% decrease in estimated glomerular filtration or dialysis; odds ratio 1.5; 95% confidence interval [CI] 1.1-2.1). Patients' risk status significantly influenced the associations of aprotinin with mortality, acute kidney injury, and massive blood loss (transfusion of > or = 10 U of red blood cells or need for surgical reexploration). Among high-risk patients, the respective odds ratios were 0.6 (CI 0.3-1.0), 1.1 (CI 0.7-1.7), and 0.7 (CI 0.4-1.04), and among low- to moderate-risk patients, they were 1.5 (CI 0.9-2.7), 2.2 (CI 1.4-3.5), and 1.2 (CI 0.9-1.07) (Breslow-Day test for homogeneity of odds ratios between high-risk versus low- to moderate-risk patients: P < 0.05 for all 3 outcomes). CONCLUSIONS: Aprotinin tends to have a better risk-benefit profile than tranexamic acid in high-risk, but not low- to moderate-risk, patients. Its use in high-risk cases may therefore be warranted.

Acute surgical anemia influences the cardioprotective effects of beta-blockade: a single-center, propensity-matched cohort study.

BACKGROUND: Despite decreasing cardiac events, perioperative beta-blockade also increases perioperative stroke and mortality. Major bleeding and/or hypotension are independently associated with these outcomes. To investigate the hypothesis that beta-blockade limits the cardiac reserve to compensate for acute surgical anemia, the authors examined the relationship between cardiac events and acute surgical anemia in patients with and without beta-blockade. METHODS: The records of all noncardiac, nontransplant surgical patients between March 2005 and June 2006 were retrospectively retrieved. The primary outcome was a composite that comprised myocardial infarction, nonfatal cardiac arrest, and in-hospital mortality (major adverse cardiac event). The lowest recorded hemoglobin in the first 3 days defined nadir hemoglobin. Propensity scores estimating the probability of receiving a perioperative beta-blocker were used to match (1:1) patients who did or did not receive beta-blockers postoperatively. The relationship between nadir hemoglobin and major adverse cardiac event was then assessed. RESULTS: This analysis identified 4,387 patients in whom nadir hemoglobin could be calculated; 1,153 (26%) patients were administered beta-blockers within the first 24 h of surgery. Propensity scores created 827 matched pairs that were well balanced for all measured confounders. Major adverse cardiac event occurred in 54 (6.5%) beta-blocked patients and in 25 (3.0%) beta-blocker naive patients (relative risk 2.38; 95% CI 1.43-3.96; P = 0.0009). The restricted cubic spline relationship demonstrated that this difference was restricted to those patients in whom the hemoglobin decrease exceeded 35% of the baseline value. CONCLUSIONS: beta-Blocked patients do not seem to tolerate surgical anemia when compared with patients who are naive to beta-blockers. Prospective studies are required to validate these findings.