Determining Optimal Treatment to Correct Preoperative Anemia and Reduce Perioperative Allogeneic Blood Transfusions in Cardiac Surgery: A Retrospective Cohort Study.

OBJECTIVE: Preoperative anemia management reduces red blood cell (RBC) transfusion and adverse outcomes, but how best to optimize the patient's hemoglobin (Hgb) before cardiac surgery remains unclear. The authors sought to determine the optimal treatment of anemia using iron and epoetin alfa before cardiac surgery. DESIGN: Retrospective cohort study. SETTING: Sunnybrook Health Sciences Centre, University of Toronto. PARTICIPANTS: The study comprised 532 consecutive patients referred to the outpatient Blood Conservation Clinic and who underwent cardiac surgery between 2008 and 2018. INTERVENTIONS: Of the 532 patients, 207 received oral iron, 84 received intravenous (IV) iron, 71 received epoetin alfa, 92 received combination therapy, and 78 received no treatment. MEASUREMENTS AND MAIN RESULTS: Multivariate linear, logistic, and Poisson regressions modelled preoperative Hgb, the change from referral to preoperative Hgb (∆Hgb), the odds of transfusion, and the number of RBC units transfused, while accounting for baseline covariates. Higher ∆Hgb was associated with IV iron >600 mg (9.80 g/L [6.17-13.42]), epoetin alfa >80,000 U (5.80 g/L [2.20-9.40]), and higher referral Hgb (1.91 g/L [1.09-2.74] per 10 g/L). Higher preoperative Hgb (odds ratio 0.76 [0.64-0.90]; count ratio 0.84 [0.77-0.93] per 10 g/L) corresponded to a lower likelihood of being transfused and transfusion of fewer RBC units. CONCLUSIONS: Preoperative IV iron >600 mg and epoetin alfa >80,000 U each was associated with significant increases in Hgb. Higher preoperative Hgb was associated with a lower likelihood of transfusion and transfusion of fewer RBC units. The authors recommend that cumulative preoperative doses of IV iron >600 mg and epoetin alfa >80,000 U be used for treatment of anemia before cardiac surgery.

Cut-off values for transit time flowmetry: are the revision criteria appropriate?

BACKGROUND: Graft Imaging to Improve Patency (GRIIP), a single-center, randomized blinded clinical trial, reported that intraoperative graft assessment with graft revision according to a priori criteria of transit time flowmetry (TTF) and intraoperative fluorescent angiography did not improve graft patency at one year after coronary artery bypass grafting (CABG) when compared with standard intraoperative management. The objective of this study is to investigate whether other TTF values are more predictive of the saphenous vein graft (SVG) failure and/or clinical outcomes. METHODS: This is a case control retrospective study of 65 SVGs from 44 patients from GRIIP. Study outcomes were graft patency at 12 months and major adverse cardiac events (MACE; death, myocardial infarction, repeat revascularization). RESULTS: Twenty-two SVGs were occluded. In receiver operating characteristic curve analysis, TTF mean flow was significantly predictive of one-year SVG failure (area under the curve = 0.698, p < 0.01), and 31 mL/min was the best cut-off value (p = 0.017, sensitivity 63.6%, specificity 67.4%). The risk of graft occlusion was 14/28, 50% for grafts with mean flow <31 mL/min and 8/37, 21.6% for grafts with mean flow ≥ 31 mL/min. In logistic regression models, mean flow was a significant predictor of early SVG failure (Odds Ratio 0.95 [0.91-0.99] per mL/min, p = 0.014) whereas other TTF values, patient comorbidities, and/or medication at discharge were not. However, TTF values were not predictive of MACE. CONCLUSIONS: TTF can identify non-functional grafts during CABG, but is of questionable value to improve one-year graft patency.

Surgical Repair of Atrial-Esophageal Fistula Following Catheter Ablation.

Left atrial-esophageal fistula after radiofrequency ablation for atrial fibrillation is a rare and potentially lethal complication. Although surgical management is associated with improved outcomes, the optimal approach remains to be elucidated. We describe a case of atrial-esophageal fistula treated with a simultaneous repair of the atrium and esophagus via a right thoracotomy with an extrapericardial off-pump approach.

A serious game for off-pump coronary artery bypass surgery procedure training.

We have begun development of an interactive, multi-player serious game for the purpose of training cardiac surgeons, fellows, and residents the series of steps comprising the Off-Pump Coronary Artery Bypass grafting (OPCAB) surgical procedure. It is hypothesized that by learning the OPCAB procedure in a "first-person-shooter gaming environment", trainees will have a much better understanding of the procedure than by traditional learning modalities. The serious game will allow for simulation parameters related to levels of fidelity to be easily adjusted so that the effect of fidelity on knowledge transfer can be examined.

Progressive simulation-based program for training cardiac surgery-related skills.

Off Pump Coronary Artery Bypass (OPCAB) surgery is a strategy for revascularizing diseased coronary arteries without cardiopulmonary bypass. The complete operation can be deconstructed into individual tasks and subtasks that are ideal for creating simulation modules. Recently, we have developed a modular mechanical beating-heart OPCAB simulator for use in learner-centered training. In the present study, we describe the design of a progressive, simulation-augmented training program for OPCAB surgery. In particular, we a) define need-driven education and training goals, b) create simulation scenarios with progressive difficulty to specifically address these goals, and c) design corresponding assessment tools for both formative and summative purposes.

The Natural History and Treatment of Cardiac Implantable Electronic Device Associated Pneumothorax-A 10-Year Single-Centre Experience.

BACKGROUND: Pneumothorax is a common complication of cardiac implantable electronic device (CIED) procedures. There is a paucity of data on the natural history and management of a CIED-associated pneumothorax. METHODS: This is a single-centre retrospective study of all consecutive patients with a CIED-associated pneumothorax between March 2010 and March 2020. Pneumothorax size was determined on all chest x-rays after device implantation and before chest tube insertion (if placed). Changes in pneumothorax size on serial chest x-rays were reported. Clinical outcomes in patients with a severe-sized pneumothorax treated with a chest tube were compared with those treated conservatively. RESULTS: A total of 86 CIED-associated pneumothoraxes were identified, with 55 (63.9%) patients having a pneumothorax severe in size. Thirty-seven patients with a severe pneumothorax received a chest tube, whereas 18 were managed conservatively. Chest tube use was associated with a higher rate of admission to hospital (100% vs 63%, P = 0.02) for patients undergoing outpatient procedure, longer length of stay (6.3 ± 3.9 vs 2.7 ± 2.9 days, P = 0.04), but fewer chest x-rays (1.9 ± 0.7 vs 4.1 ± 2.5, P = 0.002). CONCLUSION: An initial strategy of conservative management of a CIED-associated pneumothorax in select patients may be feasible and safe.

CONTEXTE: Le pneumothorax est une complication courante des interventions visant à mettre en place un dispositif cardiaque électronique implantable (DCEI). Il n'existe que très peu de données sur l'évolution naturelle et la prise en charge du pneumothorax lié à la pose d'un DCEI. MÉTHODOLOGIE: Nous avons étudié rétrospectivement les cas de patients ayant présenté un pneumothorax lié à un DCEI et traités consécutivement dans un même centre entre mars 2010 et mars 2020. La taille du pneumothorax a été déterminée dans toutes les cradiographies pulmonaires obtenues après la pose du DCEI et avant l'insertion d'un drain thoracique (le cas échéant). Les variations de la taille du pneumothorax mesurée sur les radiographies pulmonaires successives ont été rapportées. Les résultats cliniques observés chez les patients présentant un pneumothorax important traités par drainage thoracique ont été comparés à ceux de patients traités selon l'approche classique. RÉSULTATS: Au total, 86 cas de pneumothorax liés à un DCEI ont été relevés; 55 patients (63,9 %) présentaient un pneumothorax important. De ce nombre, 37 patients ont subi un drainage thoracique, tandis que les 18 autres ont été pris en charge selon l'approche classique. Le recours à un drain thoracique a été associé à un taux d'admission à l'hôpital plus élevé (100 % vs 63 %; p = 0,02) dans le cas des interventions ambulatoires et à une hospitalisation plus longue (6,3 ± 3,9 vs 2,7 ± 2,9 jours; p = 0,04), mais à un moins grand nombre de radiographies pulmonaires (1,9 ± 0,7 vs 4,1 ± 2,5; p = 0,002). CONCLUSION: Dans certains cas, il est possible et sûr d'avoir recours à une prise en charge initiale classique du pneumothorax lié à un DCEI.

Reducing redundant creatine kinase testing in cardiac injury.

BACKGROUND: Creatine kinase (CK) testing in the setting of suspected cardiac injury is commonly performed yet rarely provides clinical value beyond troponin testing. We sought to evaluate and reduce CK testing coupled with troponin testing by 50% or greater. METHODS: We performed root cause analysis to study prevailing processes and patterns of CK testing. We developed new institutional guidelines, removed CK from high-volume paper and electronic order bundles and conducted academic detailing for departments with highest ordering frequency. We evaluated consecutive patients at Sunnybrook Health Sciences Centre between 1 January 2018 and 31 March 2020 who had either a CK or troponin level measured. We prespecified successful implementation as a reduction of 50% in total CK orders and a decrease in the ratio of CK-to-troponin tests to one-third or less. We retained additional data beyond our study period to assess for sustained reductions in testing. RESULTS: Total CK tests decreased over the study period from 3963 to 2111 per month, amounting to a 46.7% reduction (95% CI 33.2 to 60.2; p<0.001) equalling 61 fewer tests per hospital day. Troponin testing did not significantly change during the intervention. Ratio of CK-to-troponin tests decreased from 0.91 to 0.49 (p<0.001). The reduction coincided with changes to order-sets, was observed across all clinical units and was sustained during additional months beyond the study period. These reductions in testing resulted in a projected annual cost savings of C$28 446. CONCLUSIONS: We demonstrate that a low-cost and feasible quality improvement initiative may lead to significant reduction in unnecessary CK testing and substantial savings in healthcare costs for patients with suspected cardiac injury.

Cardiac CT scan for preoperative planning in a patient with bilateral subclavian stenosis needing coronary artery bypass.

A 61-year-old male vasculopath presented for coronary revascularization and was found to have high-grade bilateral subclavian artery stenosis. The adequacy of the left internal mammary artery for bypass to the left anterior descending artery was in question. Rather than assessing the left internal mammary artery intraoperatively, we performed a preoperative cardiac computed tomography (CT) angiogram. This showed that the free left internal mammary artery was a suitable conduit and the procedure was performed expeditiously. Therefore, cardiac CT angiography is a noninvasive tool for preoperative planning in coronary revascularization.

The radial artery is protective in women and men following coronary artery bypass grafting-a substudy of the radial artery patency study.

BACKGROUND: Studies have demonstrated that female sex is an adverse risk factor in CABG. The primary aim of this study was to determine whether the radial artery (RA) was associated with reduced angiographic occlusion compared to the saphenous vein graft (SVG) stratified by sex in the multi-centered Radial Artery Patency Study (NCT00187356). METHODS: Between 1996-2001, 529 patients less than 80 years, with graftable triple-vessel disease underwent isolated CABG across 11 centers with late angiographic and clinical follow-up. The primary objective was to compare complete occlusion of RA and SVG with respect to sex. The secondary objective was to determine cumulative patency of both grafts along with predictors of late graft occlusion stratified by sex. The additional objective was to compare major adverse cardiac events (MACE, defined as cardiac mortality, myocardial infarction or re-intervention) between women and men. RESULTS: Of the 529 enrolled patients (13.4% women), 269 (women: n=41, 15.2%) underwent late angiography at a mean of 7.7±1.5 years after CABG. Women were older (64.1±6.7 versus 59.1±8.0 years, P<0.01) with a higher rate of diabetes (43.9% versus 28.5%, P=0.05). Smoking history was less common (48.8% versus 75.4%, P<0.01) while the mean number of grafts per patient were similar (women: 3.8±0.7, men: 3.8±0.6, P=0.65). RA occlusions were lower than SVG in women (RA: 9.8%, SVG: 26.8%, P=0.05) and in men (RA: 8.8%, SVG: 17.1%, P=0.01). The rate of RA and SVG occlusion was not statistically different between women and men, and cumulative patency curves were also similar between sexes for the RA and study SVG. Multivariable modeling showed that having a RA (versus SVG) was protective in women [odds ratio (OR) 0.15, P=0.04] and men: (OR 0.49, P=0.02). MACE (P=0.15) and event-free cardiac survival (log-rank P=0.14) were similar between women and men. CONCLUSIONS: Radial arteries are protective in both women and men with comparable burden of coronary disease and revascularization.

Comparison of Radial Artery and Saphenous Vein Graft Stenosis More Than 5 Years After Coronary Artery Bypass Grafting.

BACKGROUND: Graft stenosis may be associated with future graft failure. The purpose of this investigation was to compare graft stenosis between radial artery (RA) grafts and saphenous vein grafts (SVGs) at least 5 years postoperatively using the multicenter Radial Artery Patency Study (RAPS) data. METHODS: Two hundred thirty-four patients underwent late invasive angiography after coronary artery bypass operations. The study population consists of 163 patients with thrombolysis in myocardial infarction (TIMI) 3 flow of both the RA graft and study SVGs. Angiograms were reviewed centrally and in a blinded fashion. Graft stenosis was recorded for the proximal anastomosis, graft body, and distal anastomosis; significant stenosis was defined as greater than or equal to 50%. Major adverse cardiac events (MACE) were reported in patients with and those without significant graft stenosis. RESULTS: There was no difference in significant graft stenosis of the patent RA grafts and SVGs (14 of 163 [8.6%] versus 19 of 163 [11.7%]) or in the proximal anastomosis (5 of 163 [3.1%] versus 5 of 163 [3.1%]), graft body (6 of 163 [3.7%] versus 13 of 163 [8.0%]), or distal anastomosis (4 of 163 [2.5%] versus 5 of 163 [3.1%]) considered separately. However, the overall burden of graft body disease was higher in SVGs (p = 0.03). MACE was higher in patients with significant graft stenosis than in patients without stenosis (10 of 28 [35.7%] versus 7 of 135 [5.2%]; p < 0.0001). CONCLUSIONS: There was no significant difference in the rates of significant stenosis of patent RA grafts and SVGs more than 5 years postoperatively. However, the burden of graft body stenosis was less in RA grafts compared with SVGs, suggesting that the RA grafts will continue to outperform the SVGs late after operation.

Harmonic scalpel for pericardiectomy: novel approach to an old cardiac dilemma.

BACKGROUND: Pericardiectomy for constrictive or calcific pericarditis is a technical challenge because of dense adhesions to the epicardial surface of the heart. The procedure is fraught with the possibility of urgent cardiopulmonary bypass from excessive bleeding or cardiac laceration. We propose the use of a harmonic scalpel to perform adhesiolysis with less bleeding and cardiac trauma. METHODS AND MATERIALS: A retrospective review of 7 pericardiectomies performed with a handheld harmonic scalpel over the past 2 years was performed. Requirements for blood products, the need for cardiopulmonary bypass, and mortality were examined. RESULTS: Four of the patients underwent pericardiectomy alone, and 3 patients underwent pericardiectomy with additional cardiac procedures. The 30-day mortality was zero. No patient needed blood transfusions or urgent cardiopulmonary bypass for bleeding. No patient developed malignant arrhythmias. CONCLUSIONS: Use of a harmonic scalpel is a safe and efficient technique for pericardiectomy. Adhesiolysis is less treacherous because of the bloodless operative field; moreover, the harmonic scalpel is not arrhythmogenic.

Pedicled no-touch saphenous vein graft harvest limits vascular smooth muscle cell activation: the PATENT saphenous vein graft study.

OBJECTIVE: Neointimal hyperplasia secondary to vascular smooth muscle cell (VSMC) activation limits the long-term patency of saphenous vein grafts (SVGs). We compared markers of vascular injury and VSMC activation in SVGs harvested using the pedicled 'no-touch' (NT) vs the conventional (CON) technique. METHODS: Patients undergoing coronary artery bypass surgery were enrolled in the PATENT SVG trial (clinicaltrials.gov NCT01488084). Patients were randomly allocated to have SVGs harvested with the NT technique from one leg and the CON method from the other. SVG segments underwent morphometry, histological and electron microscopy assessments and transcript measurements of VSMC activation and differentiation markers. Leg wound functional recovery and harvest site complications were assessed using a quality-of-life questionnaire. RESULTS: A total of 17 patients (65.3 ± 7.3 years) were enrolled. SVGs harvested using the NT vs CON technique exhibited preserved intimal, medial and adventitial architecture. CON harvest was associated with greater medial Kruppel-like factor 4 transcript levels (0.26 ± 0.05 vs 0.11 ± 0.02, P < 0.05). CON samples had significantly lower medial serum response factor (0.53 ± 0.11 vs 1.44 ± 0.50, P < 0.05) and myocardin (0.59 ± 0.08 vs 1.33 ± 0.33, P < 0.05) transcript levels. MicroRNA-145, an inhibitor of VSMC activation and differentiation, was higher in the NT vs CON samples (1.84 ± 1.03 vs 0.50 ± 0.19, P < 0.05). Leg assessment scores were worse in the NT legs at 3 months, but similar to CON scores at 12 months. CONCLUSIONS: SVGs harvested using the 'NT' technique exhibit an early molecular and morphological pattern consistent with decreased VSMC activation compared with CON harvesting. Functional leg recovery was similar in both groups at 12 months. Larger studies are required to corroborate these findings.

The long-term impact of diabetes on graft patency after coronary artery bypass grafting surgery: a substudy of the multicenter Radial Artery Patency Study.

OBJECTIVES: The study objective was to determine the impact of diabetes on radial artery and saphenous vein graft occlusion and clinical outcomes more than 5 years after coronary artery bypass surgery in the multicenter Radial Artery Patency Study (NCT00187356). METHODS: A total of 529 patients aged less than 80 years with triple-vessel disease undergoing coronary bypass surgery participated in this study. Angiographic follow-up occurred more than 5 years after surgery with annual clinical follow-up. The primary objective was to compare the proportion of complete graft occlusion between radial artery and saphenous vein grafts among diabetic and nondiabetic persons. Additional objectives included determining predictors of complete graft occlusion and comparison of major adverse cardiac events defined by cardiac death, late myocardial infarction, and reintervention. RESULTS: There were 148 of 529 patients (27.8%) with diabetes; 269 patients (83/269 [30.9%] diabetic) underwent late angiography at mean of 7.7±1.5 years after surgery. In diabetic patients, the proportion of complete graft occlusion was significantly lower in the radial grafts (4/83 [4.8%]) than in the saphenous grafts (21/83 [25.3%]) (P=.0004), and this was similar in nondiabetic patients (P=.19). Multivariate modeling showed that the use of the radial artery and high-grade target vessel stenosis were protective against late graft occlusion, whereas female gender, smoking history, and elevated creatinine were associated with an increased risk; interaction between diabetic status and conduit type also was significant (P=.02). Major adverse cardiac events were higher in diabetic patients (23/148 [15.5%] vs 35/381 [9.2%], P=.04). CONCLUSIONS: The use of the radial artery should be strongly considered in diabetic patients undergoing coronary bypass surgery, especially with high-grade target vessel stenosis.

Planting the 'SEAD': early comprehensive exposure to surgery for medical students.

INTRODUCTION: The popularity of surgical specialties is declining amongst Canadian medical students. Limited early exposure of students to surgery and minor involvement of surgeons in preclerkship education are barriers to creating interest in the field. Although many informal observerships and interest groups exist, there are no structured programs in Canada that offer preclerkship medical students a comprehensive exposure to surgery. METHODS: Twenty first-year medical students participated in the Surgical Exploration and Discovery (SEAD) Program. SEAD is a pilot project at the University of Toronto providing a unique combination of (1) observerships, (2) informal discussions on surgical careers, and (3) hands-on simulation workshops across all 7 direct-entry specialties within the Department of Surgery. All participants underwent pretraining and posttraining evaluation of learning through a paper-based knowledge test and all completed a structured survey on the benefit of the course. RESULTS: Comparison of test scores revealed an overall significant improvement in learning (p<0.0001). The improvement in test scores was seen in the knowledge of all 3 components of the course (p<0.0001). Qualitative evaluation revealed a positive student experience, with 100% of students indicating that SEAD helped them identify new interests in surgical subspecialties. Finally, 100% of students stated that they would recommend the program to incoming medical students. CONCLUSION: The SEAD Program successfully improves preclerkship students' knowledge of surgical principles, understanding of a career in surgery, and basic surgical skills. Participation in the program also positively influenced their interest in pursuing a career in surgery. Programs such as SEAD may be offered to preclerkship medical students to improve their exposure to surgery at this level of training and to enhance perspectives toward surgical careers.

Simulation-augmented training program for off-pump coronary artery bypass surgery: developing and validating performance assessments.

BACKGROUND: Simulation-based programs allow trainees to be progressively challenged in a systematic, learner-centered and patient-focused fashion. The design of these programs requires an understanding of the individual steps that comprise the entire surgical procedure and our ability to assess the progress of the learner. We present the results of the design and validation of performance assessment checklists for a progressive simulation-based program in cardiac surgery. METHODOLOGY: Using a case study design, we videotaped 10 off-pump coronary artery bypass procedures and applied a new methodological framework to deconstruct the procedure into teachable components for which 6 simulation scenarios were developed. Individual checklists were designed and validated using the Delphi technique. An expert panel of 11 cardiac surgeons rated each checklist item by using a 5-point Likert-type scale and provided comments on the rating choice. The consistency of the experts' ratings were interpreted as consensus achieved when 70% of experts rated 3.5 or greater on the 5-point Likert-type scale for each assessment item. RESULTS: An in vivo workflow diagram was developed, and 6 simulation modules with progressive difficulty were selected to design an off-pump coronary artery bypass simulation-based program. The corresponding 6 assessment checklists were designed and validated. After 2 Delphi rounds, the overall average score across all checklists was 4.0, and all items were greater 3.5. The final checklists comprise between 12 and 23 items. CONCLUSION: We have demonstrated the feasibility of designing simulation-based program for complex operative procedures in a progressive fashion. The complexity at each level was given by the predefined training objectives and assessment checklists were designed and validated as content-specific assessment tools for each simulation scenario.

A framework-based approach to designing simulation-augmented surgical education and training programs.

The goal of simulation-based medical education and training is to help trainees acquire and refine the technical and cognitive skills necessary to perform clinical procedures. When designers incorporate simulation into programs, their efforts should be in line with training needs, rather than technology. Designers of simulation-augmented surgical training programs, however, face particular problems related to identifying a framework that guides the curricular design activity to fulfill the particular requirements of such training programs. These problems include the lack of (1) an objective identification of training needs, (2) a systematic design methodology to match training objectives with simulation resources, (3) structured assessments of performance, and (4) a research-centered view to evaluate and validate systematically the educational effectiveness of the program. In this report, we present a process called "Aim - FineTune - FollowThrough" to enable the connection of the identified problems to solutions, using frameworks from psychology, motor learning, education and experimental design.