Stephanie A. Fox

Monitoring brain oxygen saturation during coronary bypass surgery: a randomized, prospective study.

BACKGROUND:Cerebral deoxygenation is associated with various adverse systemic outcomes. We hypothesized, by using the brain as an index organ, that interventions to improve cerebral oxygenation would have systemic benefits in cardiac surgical patients. METHODS:Two-hundred coronary artery bypass patients were randomized to either intraoperative cerebral regional oxygen saturation (rSO2) monitoring with active display and treatment intervention protocol (intervention, n = 100), or underwent blinded rSO2 monitoring (control, n = 100). Predefined clinical outcomes were assessed by a blinded observer. RESULTS:Significantly more patients in the control group demonstrated prolonged cerebral desaturation (P = 0.014) and longer duration in the intensive care unit (P = 0.029) versus intervention patients. There was no difference in overall incidence of adverse complications, but significantly more control patients had major organ morbidity or mortality (death, ventilation >48 h, stroke, myocardial infarction, return for re-exploration) versus intervention group patients (P = 0.048). Patients experiencing major organ morbidity or mortality had lower baseline and mean rSO2, more cerebral desaturations and longer lengths of stay in the intensive care unit and postoperative hospitalization, than patients without such complications. There was a significant (r2 = 0.29) inverse correlation between intraoperative rSO2 and duration of postoperative hospitalization in patients requiring ≥10 days postoperative length of stay. CONCLUSION:Monitoring cerebral rSO2 in coronary artery bypass patients avoids profound cerebral desaturation and is associated with significantly fewer incidences of major organ dysfunction.

Simultaneous integrated coronary artery revascularization with long-term angiographic follow-up

OBJECTIVE Traditionally integrated coronary artery revascularization has been described as a 2-stage procedure. We evaluated the safety and feasibility of 1-stage, simultaneous, hybrid, robotically assisted coronary artery bypass grafting surgery and percutaneous coronary intervention. METHODS Fifty-eight patients underwent simultaneous, integrated coronary artery revascularization in an operating theater equipped with angiographic equipment. Forty-five patients were men. The mean age was 59 years. All internal thoracic arteries were harvested with robotic assistance. All anastomoses were manually constructed through a small anterior non-rib-spreading incision without cardiopulmonary bypass on the beating heart. Immediately after and within the same operative suite, both angiographic confirmation of graft patency and percutaneous coronary intervention were performed. In 52 patients therapeutic anticoagulation was achieved with the direct thrombin inhibitor bivalirudin. RESULTS There were no deaths or wound infections. There was 1 perioperative myocardial infarction. One patient had a stroke, and 3 patients required re-exploration for bleeding. The median lengths of intensive care and hospital stay were 1 and 4 days, respectively. All patients were alive and symptom free at follow-up (mean, 20.2 months; range, 1.1-40.8 months). Long-term angiographic follow-up in 54 patients showed 49 (91%) patent grafts (mean, 9.0 months; range, 4.3-40.8 months). There were 7 in-stent restenoses and 2 occluded stents. CONCLUSION For multivessel coronary artery disease, simultaneous integrated coronary artery revascularization with bivalirudin is safe and feasible. This approach enables complete multivessel revascularization with decreased surgical trauma and postoperative morbidity. Further studies are necessary to better determine patient selection and long-term outcomes.

Cumulative sum failure analysis of a policy change from on-pump to off-pump coronary artery bypass grafting

BACKGROUND Use of the sequential probability cumulative sum (CUSUM) technique may be more sensitive than standard statistical analyses in detecting a cluster of surgical failures. We applied CUSUM methods to evaluate the learning curve after a policy change by a single surgeon from routine on-pump (cardiopulmonary bypass [CPB]) to off-pump coronary artery bypass grafting (OPCAB). METHODS Fifty-five consecutive first-time coronary artery bypass patients (CPB group) were compared with the next 55 patients undergoing an attempt at routine OPCAB using the same coronary stabilizer. The goal in OPCAB patients was to obtain complete revascularization, albeit with a low threshold for conversion to CPB to maximize patient safety during the learning curve. Preoperative patient risk was calculated using previously validated models of the Cardiac Care Network of Ontario. The occurrence of operative mortality and nine predefined major complications (myocardial infarction, bleeding, stroke, renal failure, balloon pump use, mediastinitis, respiratory failure, life-threatening arrhythmia, and sepsis) was compared between the CPB and OPCAB groups using Wilcoxon, Fisher exact, and two-tailed t tests, as well as CUSUM methodology. An intention to treat analysis was performed. RESULTS The CPB and OPCAB groups had similar predicted mortality and length of stays (2.2% +/- 2.5%, 8.1 +/- 2.5 days versus 2.4% +/- 3.5%, 8.1 +/- 2.4 days, respectively). The mean number of grafts per patient was 3.1 +/- 0.7 in the CPB group versus 3.0 +/- 0.7 in the OPCAB group (p = 0.45). Two of 55 (3.6%) CPB patients died, as opposed to 1 of 55 (1.8%) OPCAB patients (p = 0.99). Eight of 55 CPB patients (14.5%) incurred major complications, as opposed to 4 of 55 (7.3%) OPCAB patients (p = 0.36). Median hospital length of stay was 6.0 days in the CPB group versus 5.0 days in the OPCAB group (p = 0.28). On CUSUM analysis, the failure curve in CPB patients approached the upper 80% alert line after eight cases, whereas the curve in OPCAB patients reached below the lower 80% (reassurance) boundary 28 cases after the policy change, indicating superior results in the OPCAB group despite the learning curve. CONCLUSIONS A policy change from coronary artery bypass on CPB to routinely attempting OPCAB can be accomplished safely despite the learning curve. CUSUM analysis was more sensitive than standard statistical methods in detecting a cluster of surgical failures and successes.

Early outcomes of coronary artery bypass with and without cardiopulmonary bypass in octogenarians

BACKGROUND Off-pump coronary artery bypass (OPCAB) surgery has been successfully used in diverse patient populations and has been postulated to be safer than conventional coronary artery bypass (CCAB) surgery in some high-risk patients, including the elderly. OBJECTIVE To compare the safety of OPCAB surgery versus CCAB surgery in the octogenarian population of two large southwestern Ontario cardiac surgical units. RESULTS Two hundred thirty-six consecutive octogenarians underwent primary isolated coronary artery bypass surgery from November 2000 to March 2005. Patients undergoing OPCAB surgery tended to have higher Parsonnet scores, while patients undergoing CCAB surgery had a greater number of emergent operations. The Canadian Cardiovascular Network predicted that mortality risk was similar in both groups. In-hospital mortality was similar between groups, as was postoperative myocardial infarction and new onset of renal dysfunction. However, in the OPCAB group, there was a decreased incidence of postoperative neurological dysfunction (2.3% in the OPCAB group versus 10.5% in the CCAB group, P=0.01), in particular cerebrovascular accidents (1.5% in the OPCAB group versus 7.6% in the CCAB group, P=0.05), and a decreased incidence of prolonged intubation (5.3% in the OPCAB group versus 13.3% in the CCAB group, P=0.04). Multivariable analysis found that cardiopulmonary bypass had no significant impact on mortality or length of stay. CONCLUSIONS In octogenarian patients, OPCAB surgery is as safe as CCAB surgery in terms of mortality and major morbidity. Furthermore, a significant reduction in neurological dysfunction and prolonged intubation was seen in the OPCAB group compared with the CCAB group.

Long-Term Angiographic Follow-Up of Robotic-Assisted Coronary Artery Revascularization

BACKGROUND Robotic-assisted coronary artery bypass grafting (CABG) has been shown in short-term studies to increase patient satisfaction and to reduce surgical morbidity and recovery times. However, the long-term patency rate of robotic-assisted CABG is unknown. Therefore, the objective of this study was to assess the long-term patency rate of robotic-assisted coronary artery bypass grafts. METHODS The study cohort included all patients who underwent robotic-assisted conduit dissection for CABG at London Health Sciences Centre between September 1999 and December 2003. These patients had selective graft patency assessment using cardiac catheterization or computed tomography angiography (CTA), or both, and stress myocardial perfusion scintigraphy (MPS) 5 to 10 years after surgery to evaluate graft patency and to give functional information on the hemodynamic significance of any graft stenosis. Patients also completed quality of life questionnaires. RESULTS From a total of 160 patients who underwent robotic-assisted CABG, 82 eligible patients were followed with graft patency assessments for a mean period of 8 years±16.3 months. The patency rate of all robotic-assisted CABG grafts in this patient cohort was 92.7%. The patency rate of left internal thoracic artery grafts to the left anterior descending artery after robotic-assisted CABG in this patient cohort was 93.4%. Patients consistently attained high scores on quality of life questionnaires after surgery. CONCLUSIONS The long-term patency rate of grafts after robotic-assisted CABG was 92.7% at a mean follow-up period of 95.8±16.3 months. Specifically, the patency rate of left internal thoracic artery grafts to the left anterior descending artery after robotic-assisted CABG was 93.4%.

Does the Trainee's Level of Experience Impact on Patient Safety and Clinical Outcomes in Coronary Artery Bypass Surgery?

Abstract  Background: There is a relative dearth of information on how the residents level of training affects patient outcomes in cardiac surgery. We designed this study to determine if there were any significant differences in patient demographics and clinical outcomes of coronary artery bypass procedures (CABG) performed by residents of PGY 4/lower, residents of PGY 5/6, fellows, or consultants. Methods: Standardized preoperative, intraoperative, and postoperative variables were prospectively collected and analyzed on 2906 isolated CABG procedures, performed between July 1999 and March 2006 with the primary surgeon prospectively classified as PGY4/lower, PGY5/6, fellow, and consultant. Results: The number of cases performed by residents of PGY4/lower, PGY5/6, fellows and consultants were 179, 263, 301, and 2163, respectively. Preoperative demographics and comorbidities were similar except PGY4/lower group had more diabetics and consultant group had more patients requiring IABP. More non‐LIMA arterial conduits were used in the consultant and fellow groups. However, there were neither significant differences in the mean number of grafts nor in the composite postoperative morbidity, median ICU, and hospital lengths of stay. Observed in‐hospital mortality was 2.2%, 1.5%, 1.7%, and 2.7% (p = 0.49), respectively. Conclusions: Preoperative patient demographics and operative data were similar in all groups except that patients requiring IABP preoperatively were more likely operated on by consultants and arterial revascularization was performed more commonly by consultants and fellows. Postoperative mortality and morbidity rates were similar among all groups, thus demonstrating that with appropriate supervision, trainees of all levels can safely be taught CABG.

Effect of off-pump coronary artery bypass grafting on risk-adjusted and cumulative sum failure outcomes after coronary artery surgery.

Abstract Background and Aim: We have shown that cumulative sum (CUSUM) failure analysis may be more sensitive than standard statistical methods in detecting a cluster of adverse patient outcomes after cardiac surgical procedures. We therefore applied CUSUM, as well as standard statistical techniques, to analyze a surgeons experience with off‐pump coronary artery bypass grafting (OPCAB) and on‐pump procedures to determine whether the two techniques have similar or different outcomes. Methods: In 320 patients undergoing nonemergent, first time coronary artery bypass grafting, preoperative patient characteristics, rates of mortality and major complications, and ICU and hospital lengths of stay were compared between the on‐pump and OPCAB cohorts using Fishers exact tests and Wilcoxon two sample tests. Predicted mortality and length of stay were determined using previously validated models of the Cardiac Care Network of Ontario. Observed versus expected ratios of both variables were calculated for the two types of procedures. Furthermore, CUSUM curves were constructed for the on‐pump and OPCAB cohorts. A multivariable analysis of the predictors of hospital length of stay was also performed to determine whether the type of coronary artery bypass procedure had an independent impact on this variable. Results: The predicted mortality risk and predicted hospital length of stay were almost identical in the 208 on‐pump patients ( 2.2 ± 3.9% ; 8.2 ± 2.5 days) and the 112 OPCAB patients ( 2.0 ± 2.2% ; 7.8 ± 2.1 days). The incidence of hospital mortality and postoperative stroke were 2.9% and 2.4% in on‐pump patients versus zero in OPCAB patients (p= 0.09 and 0.17, respectively). Mechanical ventilation for greater than 48 hours was significantly less common in OPCAB (1.8%) than in on‐pump patients (7.7%, p= 0.04). The rate of 10 major complications was 14.9% in on‐pump versus 8.0% in OPCAB patients (p= 0.08). OPCAB patients experienced a hospital length of stay that was a median of 1.0 day shorter than on‐pump patients (p= 0.01). The observed versus expected ratio for length of stay was 0.78 in OPCAB patients versus 0.95 in on‐pump patients. On CUSUM analysis, the failure curve in OPCAB patients was negative and was flatter than that of on‐pump patients throughout the duration of the study. Furthermore, OPCAB was an independent predictor of a reduced hospital length of stay on multivariable analysis. Conclusions: OPCAB was associated with better outcomes than on‐pump coronary artery bypass despite a similar predicted risk. This robust finding was documented on sensitive CUSUM analysis, using standard statistical techniques and on a multivariable analysis of the independent predictors of hospital length of stay.(J Card Surg 2002;17:520‐528)

Impact of the opening of a specialized cardiac surgery recovery unit on postoperative outcomes in an academic health sciences centre.

PurposeIt is controversial as to whether cardiac surgery patients are optimally managed in a mixed medical-surgical intensive care unit (ICU) or in a specialized postoperative unit. We conducted a prospective cohort study in an academic health sciences centre to compare outcomes before and following the opening of a specialized cardiac surgery recovery unit (CSRU) in April 2005.MethodsThe study cohort included 2,599 consecutive patients undergoing coronary artery bypass grafting (CABG), valve and combined CABG-valve procedures from April 2004 to March 2006. From April 2004 to March 2005 (year 1) all patients received postoperative care in mixed medical-surgical ICUs at two different sites staffed by critical care consultants, fellows and residents. From April 2005 until March 2006 (year 2) patients were cared for in a newly-established CSRU on one site staffed by cardiac anesthesiology fellows, a nurse practitioner and consultants in critical care, cardiac anesthesiology and cardiac surgery. The effect of this change on in-hospital mortality, the incidence of ten major postoperative complications, postoperative ventilation hours, readmission rates and case cancellations due to a lack of capacity was assessed using Chi-square or Wilcoxon tests, where appropriate.ResultsCoronary artery bypass grafting, valve and combined CABG-valve mortality rates were similar in years 1 and 2. There was a significant reduction in the composite major complication rate (16.3% to 13.0%,P = 0.02) and in median postoperative ventilation hours (8.8vs 8.0 hr,P = 0.005) from year 1 to 2. On multivariable logistic regression analysis, the pre-merger interval (year 1) was a significant independent predictor of the occurrence of death or major complications.ConclusionA specialized CSRU with a multi-disciplinary consultant model was associated with stable or improved outcomes postoperatively, when compared to a mixed medical-surgical ICU model of cardiac surgical care.RésuméObjectifLa question de savoir si les patients de chirurgie cardiaque sont traités de façon optimale dans une unité de soins intensifs mixte, c’est-à-dire médico-chirurgicale, ou dans une unité postopératoire spécialisée, demeure controversée. Nous avons mené une étude de cohorte prospective dans un centre de santé universitaire afin de comparer les devenirs avant et après l’ouverture d’une unité spécialisée de rétablissement après chirurgie cardiaque (CSRU) en avril 2005.MéthodeLa cohorte de l’étude a été constituée de 2 599 patients consécutifs subissant une chirurgie de revascularisation coronarienne, un remplacement valvulaire, et des chirurgies combinant les deux procédures entre avril 2004 et mars 2006. D’avril 2004 à mars 2005 (1ère année), tous les patients ont été traités dans des unités de soins intensifs mixtes dans deux différents sites employant des consultants en soins intensifs, des fellows et des résidents. D’avril 2005 à mars 2006 (2ème année), les patients ont été pris en charge dans une nouvelle unité CSRU dans un seul site, dont le personnel se composait de fellows en anesthésie cardiaque, d’un infirmier praticien et de consultants en soins intensifs, en anesthésie cardiaque et en chirurgie cardiaque. L’effet de ce changement sur la mortalité à l’hôpital, l’incidence de dix complications postopératoires majeures, le nombre d’heures de ventilation postopératoire, les taux de réadmission et les annulations de cas par manque de capacité, ont été évalués à l’aide des tests du chi-carré et de Wilcoxon, lorsqu’ils étaient adaptés.RésultatsLes tauxde mortalité pourlespontages aortocoronariens, les remplacements valvulaires et les chirurgies combinées étaient similaires la première et la deuxième année. Il y a eu une réduction significative dans le taux composite de complications majeures (de 16,3% à 13,0 %,P = 0,02) et dans la moyenne du nombre d’heures de ventilation postopératoire (8,8 vs 8,0 hres, P = 0,005) entre la première et la deuxième année. Dans l’analyse multivariée de régression logistique, l’intervalle avant la fusion (1ère année) a constitué un prédicteur indépendant significatif de l’incidence de décès ou de complications majeures.ConclusionUn modèle d’unité CSRU spécialisée avec des consultants pluridisciplinaires a été associé à des devenirs postopératoires stables ou meilleurs par rapport à un modèle d’unité de soins intensifs mixte médico-chirurgical pour les soins post-chirurgie cardiaque.

Comparison of isoflurane and sevoflurane in cardiac surgery: a randomized non-inferiority comparative effectiveness trial

PurposeVolatile anesthetics possess cardioprotective properties, but it is unknown if the cardioprotective effects extend equally to all members of the class. Although sevoflurane is a relatively newer anesthetic than isoflurane, its introduction into practice was not preceded by a head-to-head comparison with isoflurane in a trial focusing on clinically important outcomes. Our objective was to determine whether sevoflurane was non-inferior to isoflurane on a clinically important primary outcome in a heterogeneous group of adults undergoing cardiac surgery.MethodsThis was a pragmatic randomized non-inferiority comparative effectiveness clinical trial in 464 adults having coronary artery bypass graft and/or single valve surgery during November 2011 to March 2014. The intervention was maintenance of anesthesia with sevoflurane (n = 231) or isoflurane (n = 233) administered at a dose of 0.5-2.0 MAC throughout the entire operation. All caregivers were blinded except for the anesthesiologist and perfusionist. The primary outcome was a composite of intensive care unit (ICU) length of stay ≥ 48 hr and all-cause 30-day mortality. We hypothesized that sevoflurane would be non-inferior to isoflurane (non-inferiority margin < 10% based on an expected event rate of 25%). Secondary outcomes included prolonged ICU stay, 30- and 365-day all-cause mortality, inotrope or vasopressor usage, new-onset hemodialysis or atrial fibrillation, stroke, and readmission to the ICU.ResultsNo losses to follow-up occurred. The primary outcome occurred in 25% of sevoflurane patients and 30% of isoflurane patients (absolute difference, −5.4%; one-sided 95% confidence interval, 1.4), thus non-inferiority was declared. Sevoflurane was not superior to isoflurane for the primary outcome (P = 0.21) or for any secondary outcomes.ConclusionSevoflurane is non-inferior to isoflurane on a composite outcome of prolonged ICU stay and all-cause 30-day mortality. Sevoflurane is not superior to isoflurane on any other of the clinically important outcomes. This trial was registered at clinicaltrials.gov; NCT01477151.RésuméObjectifLes agents anesthésiques volatils possèdent des propriétés cardioprotectrices, mais nous ne savons pas si ces effets cardioprotecteurs sont équivalents pour tous les agents de cette classe. Bien que le sévoflurane soit un anesthésique plus récent que l’isoflurane, son introduction dans notre pratique n’a pas été précédée par une comparaison directe à l’isoflurane dans une étude s’intéressant à d’importants critères d’évaluation cliniques. Notre objectif était de déterminer si le sévoflurane était non inférieur à l’isoflurane en relation à un critère d’évaluation principal important d’un point de vue clinique dans un groupe hétérogène d’adultes subissant une chirurgie cardiaque.MéthodeNous avons réalisé une étude clinique randomisée et pragmatique d’efficacité comparative et de non-infériorité auprès de 464 adultes subissant des pontages coronariens et/ou une chirurgie valvulaire unique entre novembre 2011 et mars 2014. L’intervention consistait en le maintien de l’anesthésie à l’aide de sévoflurane (n = 231) ou d’isoflurane (n = 233) administré à une dose de 0,5-2,0 MAC tout au long de l’opération. Aucun intervenant ne connaissait l’agent utilisé, à l’exception de l’anesthésiologiste et du perfusionniste. Le critère d’évaluation principal était une composée de la durée de séjour à l’unité de soins intensifs (USI) ≥ 48 h et de la mortalité, toutes causes confondues, à 30 jours. Nous avons émis l’hypothèse que le sévoflurane ne serait pas inférieur à l’isoflurane (marge de non-infériorité < 10 % sur la base d’un taux de complications attendu de 25 %). Les critères d’évaluation secondaires comprenaient un séjour prolongé à l’USI, la mortalité toutes causes confondues à 30 et à 365 jours, l’utilisation d’inotropes ou de vasopresseurs, une hémodialyse ou une fibrillation auriculaire nouvelles, un accident vasculaire cérébral et une réadmission à l’USI.RésultatsNous n’avons perdu aucun patient au suivi. Le critère d’évaluation principal est survenu chez 25 % des patients ayant reçu du sévoflurane et 30 % des patients ayant reçu de l’isoflurane (différence absolue, −5,4 %; intervalle de confiance unilatéral 95 %, 1,4): la non-infériorité a donc été déclarée. Le sévoflurane n’était pas supérieur à l’isoflurane en ce qui touchait au critère d’évaluation principal (P = 0,21) ou aux critères d’évaluation secondaires.ConclusionLe sévoflurane n’est pas inférieur à l’isoflurane selon un critère d’évaluation composé d’une durée de séjour prolongée à l’USI et de la mortalité toutes causes confondues à 30 jours. Le sévoflurane n’est pas supérieur à l’isoflurane en ce qui touche à n’importe quel autre critère clinique important. Cette étude a été enregistrée au ClinicalTrials.gov, numéro NCT01477151.

Postoperative atrial fibrillation is not pulmonary vein dependent: Results from a randomized trial

BACKGROUND Although often short-lived and self-limiting, postoperative atrial fibrillation (POAF) is a well-recognized postoperative complication of cardiac surgery and is associated with a 2-fold increase in cardiovascular mortality and morbidity. OBJECTIVE Our aim was to determine whether intraoperative bilateral pulmonary vein radiofrequency ablation decreases the incidence of POAF in patients undergoing coronary artery bypass grafting (CABG). METHODS A total of 175 patients undergoing CABG was prospectively randomized to undergo adjuvant bilateral radiofrequency pulmonary vein ablation in addition to CABG (group A; n = 89) or CABG alone (group B; n = 86). Intraoperative pulmonary vein isolation was confirmed by the inability to pace the heart via the pulmonary veins after ablation. All patients received postoperative β-blocker. RESULTS There was no difference in the incidence of POAF in the treatment group who underwent adjuvant pulmonary vein ablation (group A; 37.1%) compared with the control group who did not (group B; 36.1%) (P = .887). There were no differences in postoperative inotropic support, antiarrhythmic drug use, need for oral anticoagulation, and complication rates. The mean length of postoperative hospital stay was 8.2 ± 6.5 days in the ablation group and 6.7 ± 4.6 days in the control group (P < .001). CONCLUSION Adjuvant pulmonary vein isolation does not decrease the incidence of POAF or its clinical impact but increases the mean length of stay in the hospital. The mechanism of POAF does not appear to depend on the pulmonary veins.