What is Transferred and How Much is Retained? A Simulation Study of Complex Surgical Skills.

INTRODUCTION: Studies indicate that learning surgical skills on low-fidelity models is equally beneficial to learning on high-fidelity models in terms of skills retention and transfer. However, it is unclear how low-fidelity simulation training impacts retention and transfer in novice learners, particularly on complex surgical tasks that incorporate multiple challenging skills. This study explores the capacity of complete novices to learn and transfer complex surgical skills from a low-fidelity model to a high-fidelity simulation after a delay. METHODS: Task-naïve medical and nonmedical undergraduate students (n = 62) participated in a three-phase prospective double-arm randomized (2:1) experimental study. Participants completed two skills training sessions (end-to-side anastomosis) on a low-fidelity bench model. After a 4-week delay, participants completed the task again either using the low-fidelity model or a high-fidelity model (cadaver) and were assessed using a validated checklist. RESULTS: There was a significant time × fidelity group interaction (P = 0.004). Simple effects analysis indicated the high-fidelity group (Mdiff = 4.18, P < 0.001) performed significantly worse (P = 0.003) in phase 3 relative to phase 2 compared to the low-fidelity group (Mdiff = 0.75, P = 0.39). Post hoc logistic regression analysis indicated that radial suturing technique and economy of motion skills were less likely to be completed correctly for those in the high-fidelity group. CONCLUSIONS: These findings suggest that for novice populations, relying on low-fidelity simulation training as a source of teaching complex skills may not provide a reliable transfer to high-fidelity models and in turn clinical settings.

Evaluation of tricuspid and pulmonary valves using epicardial and transesophageal echocardiography--a comparative study.

OBJECTIVE: To compare measurements obtained by transesophageal echocardiography (TEE) and epicardial echocardiography (EE) for evaluation of the tricuspid valve (TV) and pulmonary valve (PV). DESIGN: Prospective observational. SETTING: University hospital. PARTICIPANTS: Patients undergoing elective coronary artery bypass grafting with or without aortic valve replacement. INTERVENTIONS: After routine intraoperative TEE, EE was performed to compare measurements obtained by the 2 methods. MEASUREMENTS AND MAIN RESULTS: After institutional review board approval, 25 patients >18 years old were recruited. Biases with EE versus TEE for E and A waves were 11.9 cm/second (95% confidence interval [CI], 48.2 to -24.4) and 6.8 cm/second (95% CI, 28 to -15), respectively, and for E/A ratio was 0.08 (95% CI, 1.2 to -1). Pulmonary velocity bias was 57.94 cm/second (95% CI, 192.9 to -76.98), with higher values using EE. Bias for pulmonary trunk diameter was -0.31 cm (95% CI, 1.5 to -2.1). For quality of images, means were 2.4 (standard deviation [SD], 1.0) for EE and 2.3 (SD, 0.57) with TEE for TV and 2.4 (SD, 1.0) with EE and 2.5 (SD, 1.0) with TEE for PV. For the number of leaflets visualized, means were 2.2 (SD, 1.0) with EE and 2.5 (SD, 0.5) with TEE for TV and 2.5 (SD, 0.5) for EE and 1.3 (SD, 1.1) with TEE for PV. CONCLUSIONS: There was good agreement for Doppler measurements across TVs; however, measurements across PVs were significantly higher with EE versus TEE. TV Doppler measurements were difficult to acquire even for surgeons experienced in epiaortic scanning.

The role of epicardial echocardiography in the measurement of transvalvular flow velocities during aortic valve replacement.

OBJECTIVE: The purpose of this study was to compare transvalvular flow velocities obtained by transesophageal echocardiography and epicardial echocardiography (EE) during aortic valve replacement (AVR). DESIGN: Prospective observational study. SETTING: University hospital. PARTICIPANTS: Patients undergoing AVR for aortic stenosis. INTERVENTIONS: After institutional review board approval, 17 patients undergoing AVR consented. Deep transgastric (deep TG LAX) and transgastric long-axis (TG LAX) views and epicardial aortic valve long-axis views (S8 probe) were obtained on a SONOS 5500 (Phillips Medical Systems, Bothell, WA) before and after AVR. Transvalvular flow velocity and velocity time integral (VTI) were recorded via each technique. Measurements were made offline by 2 independent reviewers. Agreement between measurements made by different views was evaluated by using Bland-Altman analysis. MEASUREMENTS AND MAIN RESULTS: The epicardial probe was well tolerated. Quality images were obtained in all patients with TEE and 30 of 34 studies via epicardial scanning. The mean bias for peak velocities derived through EE and deep TG LAX was 96.3 cm/s (95% confidence interval [CI], 51.1-141.4) before AVR and 58 cm/s (95% CI, 32.4-83.7) after AVR. The mean bias for peak velocities between EE and TG LAX was 70 cm/s (95% CI, 31.1-108.9) before and 84.7 cm/s (95% CI, 55.6-113.7) after AVR. Similar results were obtained for VTI. CONCLUSIONS: Peak transaortic valve velocities and VTI measured with epicardial echocardiography are higher in comparison to measurements via TEE in patients undergoing AVR. The precise role of epicardial echocardiography in the comprehensive echocardiographic examination of patients undergoing aortic valve replacement needs further evaluation.

A simulated training model for laparoscopic pyloromyotomy: Is 3D printing the way of the future?

BACKGROUND: Hypertrophic pyloric stenosis (HPS) is a common neonatal condition treated with open or laparoscopic pyloromyotomy. 3D-printed organs offer realistic simulations to practice surgical techniques. The purpose of this study was to validate a 3D HPS stomach model and assess model reliability and surgical realism. METHODS: Medical students, general surgery residents, and adult and pediatric general surgeons were recruited from a single center. Participants were videotaped three times performing a laparoscopic pyloromyotomy using box trainers and 3D-printed stomachs. Attempts were graded independently by three reviewers using GOALS and Task Specific Assessments (TSA). Participants were surveyed using the Index of Agreement of Assertions on Model Accuracy (IAAMA). RESULTS: Participants reported their experience levels as novice (22%), inexperienced (26%), intermediate (19%), and experienced (33%). Interrater reliability was similar for overall average GOALS and TSA scores. There was a significant improvement in GOALS (p<0.0001) and TSA scores (p=0.03) between attempts and overall. Participants felt the model accurately simulated a laparoscopic pyloromyotomy (82%) and would be a useful tool for beginners (100%). CONCLUSION: A 3D-printed stomach model for simulated laparoscopic pyloromyotomy is a useful training tool for learners to improve laparoscopic skills. The GOALS and TSA provide reliable technical skills assessments. LEVEL OF EVIDENCE: II.

Cardiac-Referenced Leukocyte Telomere Length and Outcomes After Cardiovascular Surgery.

Leukocyte telomere shortening reflects stress burdens and has been associated with cardiac events. However, the patient-specific clinical value of telomere assessment remains unknown. Moreover, telomere shortening cannot be inferred from a single telomere length assessment. The authors investigated and developed a novel strategy for gauging leukocyte telomere shortening using autologous cardiac atrial referencing. Using multitissue assessments from 163 patients who underwent cardiovascular surgery, we determined that the cardiac atrium-leukocyte telomere length difference predicted post-operative complexity. This constituted the first evidence that a single-time assessment of telomere dynamics might be salient to acute cardiac care.

A Prospective Randomized Study of Endoscopic Versus Conventional Harvesting of the Radial Artery.

OBJECTIVE: The aims of the study were to determine whether endoscopic harvesting of the radial artery (RA) reduces morbidity due to pain, infection, and disability with improvement in satisfaction and cosmesis compared to the conventional technique and (2) to compare the 6-month angiographic patency of the RA harvested conventionally and endoscopically. METHODS: In a prospective randomized study, 119 patients undergoing coronary artery bypass grafting using the RA were randomized to have RA harvested either conventionally (n = 59) or endoscopically (n = 60). RESULTS: Radial artery harvest time (open wound time) was significantly reduced in the endoscopic group (36.5 ± 9.4 vs 57.7 ± 9.4 minutes, P < 0.001). Only one patient developed wound infection (1.6%) in the endoscopic group compared with six patients (10.2%), P = 0.061, in the conventional group. Although this was not statistically significant, clinically this was relevant in terms of reduction in postoperative morbidity. Postoperative pain in the arm incision was significantly lower in the endoscopic group at postoperative day 2 (P < 0.001) and at discharge (P < 0.001) and similar to the conventional open group at 6 weeks' follow-up (P = 0.103). Overall patient satisfaction and cosmesis were significantly better in the endoscopic group at postoperative day 2 (P < 0.001), at discharge (P < 0.001), and at 6 weeks' follow-up (P < 0.001). There was no difference in the arm disability postoperatively (P = 0.505) between the two groups. Six-month angiographic assessment of 23 patients (12 endoscopic and 11 open) revealed no difference in the patency rate (10/12 in endoscopic and 9/11 in open group). CONCLUSIONS: Endoscopic RA harvesting reduced the incidence of postoperative wound infection and wound pain and improved patient satisfaction and cosmesis compared with conventional harvesting technique. There was no difference in the 6-month angiographic patency of the RA harvested conventionally and endoscopically.

Association of homocysteine and smoking with cerebral microemboli in patients with mechanical heart valves: a transcranial Doppler study.

Objectives: Microembolic signals (MES) on transcranial Doppler (TCD) predict stroke and cognitive decline. Plasma levels of total homocysteine (tHcy), a prothrombotic factor, are higher in patients with microemboli in carotid stenosis and in patients with paradoxical embolism. In this study we assessed the association between the level of tHcy and the number of MES in patients with mechanical heart valves (MHVs). Methods: TCD monitoring was performed to detect MES before and after breathing 100% oxygen and repeated every 2-4 weeks up to six times. Results: Twenty-five patients with MHVs (mean age: 63.60±10.15 years) participated in this study; 15 were men (66.47±7.25 years) and 10 were women (59.30±12.60 years). In total, there were 126 study visits. In multiple regression, higher tHcy was associated with more MES in both preoxygenation (OR 1.34 (95% CI 1.07 to 1.68, P=0.009)) and postoxygenation (OR 1.40 (95% CI 1.07 to 1.83, P=0.01)) phases. Current smoking and the length of time between the operation and monitoring also correlated with a higher number of MES before and after breathing oxygen, particularly in women. Conclusions: Higher tHcy and smoking were associated with a higher MES count in both preoxygenation and postoxygenation phases. Because smoking can be stopped and hyperhomocysteinaemia is treatable, these are clinically important findings.

Trainee Perceptions of the Canadian Cardiac Surgery Workforce: A Survey of Canadian Cardiac Surgery Trainees.

Management of cardiac surgery health human resources (HHR) has been challenging, with recent graduates struggling to secure employment and a shortage of cardiac surgeons predicted as early as 2020. The length of cardiac surgery training prevents HHR supply from adapting in a timely fashion to changes in demand, resulting in a critical need for active workforce management. This study details the results of the 2015 Canadian Society of Cardiac Surgeons (CSCS) workforce survey undertaken as part of the CSCS strategy for active workforce management. The 38-question survey was administered electronically to all 96 trainees identified as being registered in a Canadian cardiac surgery residency program for the 2015-2016 academic year. Eighty-four of 96 (88%) trainees responded. The majority of participants were satisfied with their training experience. However, 29% stated that their clinical and operative exposure needed improvement, and 57% of graduating trainees did not believe that they would be competent to practice independently at the conclusion of their training. Although 51% of participants believe the job market is improving, 94% of senior trainees found it competitive or extremely difficult to secure an attending staff position. Participants highlighted a need for improved career counselling and formal mentorship. Although the job market is perceived to be improving, a mismatch in the cardiac surgery workforce supply and demand remains because current trainees continue to experience difficulty securing employment after the completion of residency training. Trainees have identified improved career counselling and mentorship as potential strategies to aid graduates in securing employment.

Increasing peak expiratory flow time in amyotrophic lateral sclerosis.

BACKGROUND: Serial measurements of pulmonary function to indicate decreasing respiratory muscle strength in patients with amyotrophic lateral sclerosis (ALS) is well documented. Quantitative outcome measures include declining FVC, FEV1, maximal inspired pressure, maximal expired pressure, and maximal voluntary ventilation. Increasing peak expiratory flow time (PEFT) may represent a further sensitive measure of declining respiratory muscle strength in ALS. METHODS: Fifty-five patients with ALS performed flow-volume loops serially after presentation. The percentage change from baseline values for FVC, peak expiratory flow (PEFR), and PEFT were compared using Spearman correlation coefficients. The prolongation of PEFT with serial tests was analyzed using a Kruskal-Wallis with a Dunn multiple comparison test. Bulbar-onset and limb-onset PEFT was compared using the Mann-Whitney test. RESULTS: PEFT was significantly increased from baseline values at all follow-up tests. However, PEFTs measured at the third, fourth, fifth, and sixth visits, although higher, were not significantly different. Significant negative correlations existed between the increase in PEFT and the decrease in PEFR and FVC. Significant positive correlations existed between the increase in PEFT and days from diagnosis and the decrease in PEFR and decrease in FVC. CONCLUSION: PEFT increases significantly and linearly with time in patients with ALS and may begin to plateau with bulbar symptoms. PEFT increases at a faster rate than the rate of decline in both FVC and PEFR. PEFT is a quantitative measure of decreasing pulmonary function in ALS that is easily measured.

Use of the Impella 5.0 Device as a Bridge to Recovery in Adult Fulminant Viral Myocarditis.

We present a case of a 48-year-old female patient successfully bridged to recovery with the Impella 5.0 microaxial pump (Abiomed, Danvers, MA USA) after presenting with cardiogenic shock secondary to acute fulminant viral myocarditis. After 1 week of flu-like symptoms, the patient presented to her community emergency department with chest pain and hypotension. A diagnosis of inferior ST elevation myocardial infarction was made; subsequent angiography demonstrated normal coronary arteries and a left ventricular ejection fraction of 10%. A provisional diagnosis of viral myocarditis was made. As her condition deteriorated further, she underwent insertion of an Impella 5.0 after failure of supportive medical therapy. Myocardial recovery occurred, and the Impella was removed after 1 week. After a prolonged cardiac intensive care unit stay requiring temporary hemodialysis, the patient recovered sufficiently to tolerate device explant, transfer to the recovery ward, and ultimate discharge home. This case report highlights the benefit of mechanical circulatory support in a patient with cardiogenic shock from viral myocarditis as well as some of the complications that can occur in this critically ill subset of patients.

Long-term patency of endoscopically harvested radial arteries: from a randomized controlled trial.

OBJECTIVE: From 2005 to 2007, 119 patients were enrolled in a prospective randomized controlled trial comparing open and endoscopically harvested radial arteries for coronary artery bypass grafting. The objective of the current study was to compare graft patency between intervention groups at more than 5 years from the initial trial. We hypothesized that endoscopically harvested radial arteries would show equivalent patency to those conventionally harvested. METHODS: At 5 years or greater from their operation, all consenting patients underwent a single-day anatomic and functional cardiac assessment with coronary computed tomography angiography and sestamibi myocardial perfusion scanning. Medical Outcomes Study 36-Item Short-Form Health Surveys and Seattle Angina Questionnaires were completed to assess the overall quality of life. All patients had received calcium channel blocker therapy for at least 6 months postoperatively. RESULTS: The mean (SD) duration of follow-up was 79.2 (8.6) months for all patients. One death occurred within 30 days of coronary artery bypass grafting in each treatment group, and eight additional noncardiac deaths occurred during the study time frame. Of 119 patients, 66 consented to follow-up. Thirty-two had open radial artery harvest, and 34 had endoscopic radial artery harvest. At more than 5 years, there were 28 patent conventionally harvested radial arteries (87.5%) and 31 patent endoscopically harvested radial arteries (91.2%) (P = 0.705). Measured quality of life was comparable between groups. CONCLUSIONS: Endoscopic radial artery harvest is safe and effective when compared with open radial artery harvest, with excellent graft patency demonstrated at more than 5 years. Patency results are noninferior in endoscopic radial artery harvest.

Pyopneumopericardium caused by mediastinal granuloma.

We report the case of a previously healthy 32-year-old man who was seen with flulike symptoms, dyspnea, and chest pain. The diagnosis was pyopneumopericardium, and pericardial tap revealed 1.3 L of purulent material. Computed tomography of the chest demonstrated a calcified mass inferior to the carina. Urgent exploration through a right thoracotomy revealed that the mass was adherent to the esophagus and pericardium. The subcarinal mass was resected. Pathological study demonstrated granulomatous lymph nodes, which were likely due to histoplasmosis. This is among the first reports of granulomatous erosion into the pericardium causing pyopneumopericardium. The patient made a good recovery, and his case demonstrates the importance of early imaging and mediastinal exploration for pyopneumopericardium.

Blood transfusions are associated with urinary biomarkers of kidney injury in cardiac surgery.

OBJECTIVE: Cardiac surgery is a major cause of acute kidney injury. In this setting, receipt of blood transfusions seems to be associated with a higher risk of acute kidney injury, as measured using serum creatinine values. We examined this association further by using urinary biomarkers of kidney injury. METHODS: A total of 1210 adults underwent cardiac surgery and were divided into 3 groups on the basis of the receipt of intraoperative packed red blood cell units: no blood (n = 894), 2 or less packed red blood cell units (n = 206), and more than 2 packed red blood cell units (n = 110). Acute kidney injury was defined as (1) doubling of serum creatinine from the preoperative value; (2) first postoperative urinary interleukin-18 in the fifth quintile; and (3) first postoperative urinary neutrophil gelatinase-associated lipocalin in the fifth quintile. We determined the relative risk for acute kidney injury outcome according to packed red blood cell units group after adjusting for 12 preoperative and surgical variables. By using the Sobel test for mediation analysis, we also evaluated the role of biomarkers in causing acute kidney injury through alternative pathways. RESULTS: Acute kidney injury was more common in those who received more than 2 packed red blood cell units. In patients receiving more than 2 packed red blood cell units, the adjusted relative risks were 2.3 (95% confidence interval, 1.2-4.4, P .01), 1.36 (95% confidence interval, 1.0-1.9, P .05), and 1.34 (95% confidence interval, 1.0-1.8, P .06) for doubling of serum creatinine, urinary interleukin-18 in the fifth quintile (>60 pg/mL), and urinary neutrophil gelatinase-associated lipocalin in the fifth quintile (>102 ng/mL), respectively. Furthermore, the effect of packed red blood cell units transfusion on acute kidney injury was partially mediated by interleukin-18. CONCLUSIONS: Receipt of 2 or more packed red blood cell units during cardiac surgery is associated with a greater risk of acute kidney injury defined by serum creatinine and kidney injury biomarkers.

Increased uptake of guideline-recommended oral antiplatelet therapy: insights from the Canadian acute coronary syndrome reflective.

Current guideline-based recommendations for oral dual-antiplatelet therapy in an acute coronary syndrome (ACS) include the use of newer adenosine diphosphate receptor inhibitor (ADPri) regimens and agents. The Canadian ACS Reflective Program is a multicenter observational quality-enhancement project that compared the use of ADPri therapy in 2 phases (November 2011-March 2013 and April 2013-November 2013) and also compared ADPri use with previous national data from the Canadian Global Registry of Acute Coronary Events (2000-2008). Of 3099 patients with ACS, 30.6% had ST-segment elevation myocardial infarction (STEMI), 52.3% had non-STEMI, and 17% had unstable angina. There was high use of dual-antiplatelet therapy for ≤ 24 hours, with important increases noted when compared with previous national experience (P for trend, < 0.0001). Clopidogrel was the most commonly used ADPri (82.2%), with lower use of the newer agents ticagrelor (9.0%) and prasugrel (3.1%). Ticagrelor and prasugrel use was most frequent in patients with STEMI undergoing percutaneous coronary intervention PCI (34.3%). There was relatively lower use of ADPri therapy at discharge; it was given mainly to patients who did not undergo PCI (68.2%) and to those with non-ST-elevation ACS (82%). When comparing the 2 consecutive phases of data collection in the ACS Reflective, there was an approximate 3- and 2-fold increase in the early and discharge use of the newer ADPri agents, respectively. In conclusion, there has been a temporal increase in ADPri use compared with previous national experience and an increased uptake of newer ADPri agents. Additional work is needed to identify and address barriers limiting optimal implementation of these newer guideline-recommended agents into routine Canadian practice.

Use of clopidogrel post-coronary artery bypass surgery in canadian patients with acute coronary syndromes.

BACKGROUND: Randomized trials have established the efficacy of clopidogrel in acute coronary syndromes (ACS). The benefit of clopidogrel has also been observed in the subgroup of ACS patients who subsequently undergo coronary artery bypass surgery (CABG); however, this therapy is discontinued preoperatively and the frequency with which clopidogrel is restarted post-CABG is unknown. METHODS: We examined the pattern of clopidogrel use in the Canadian Global Registry of Acute Coronary Events (GRACE), GRACE2, and CANRACE (2003-2008) post-CABG ACS patients. We stratified the patients according to whether they underwent CABG during their index hospitalization for ACS and whether they were prescribed clopidogrel at discharge. RESULTS: Among those patients in whom clopidogrel status at discharge was known, 5904 (60%) of 9841 were discharged from hospital on clopidogrel. Use of clopidogrel at discharge was observed in 2222 (40.8%) of 5443 patients who were medically managed (ie, did not undergo percutaneous coronary intervention [PCI] or CABG) and in 3585 (90.1%) of 3980 patients who underwent in-hospital PCI. Overall, 455 (3.3%) of 13,776 patients underwent CABG during the index hospitalization; 255 (56%) patients were started on clopidogrel during the first 24 hours, and 66 of these patients (25.9%) were discharged on clopidogrel. In contrast, 5681 (61.3%) of the 9262 patients who did not undergo in-hospital CABG were discharged on clopidogrel. CONCLUSIONS: Although current guidelines recommend the use of clopidogrel post-CABG in patients with ACS, our observations suggest that only 1 in 4 or 5 Canadian patients are discharged on this therapy.

The new cardiac surgery patient: defying previous expectations.

BACKGROUND: Studies conducted before 1999 of patients who had coronary artery bypass graft surgery (CABG) have shown a tendency toward increasing preoperative risk factors. This study examines whether this trend of increasing risk in patients who have cardiac surgery has continued since 1999 and whether its effect on mortality and morbidity has changed. METHODS: We prospectively collected data for 2754 patients who had cardiac surgery, divided them into 4 cohorts based on the year of operation (2000-2003) and analyzed the data according to 56 predefined preoperative, operative and postoperative variables. RESULTS: There were no significant changes in most preoperative risk factors over time, except for significant decreases in the proportion of elective (p = 0.016) and emergency/salvage operations (p < 0.001) and increases in urgent procedures and in the number of patients with congestive heart failure (CHF) (p < 0.001). The proportion of CABG procedures decreased significantly, whereas the proportion of valve, CABG plus valve, and non-CABG surgeries increased. A significant increase in multiarterial graft use and a decrease in off-pump coronary artery bypass procedures were observed. Postoperative complication rates did not change during the 4 years except for a significant decrease in wound infections. No significant changes in overall mortality and mortality across types of procedure were observed. Median observed/expected ratios for expected length of stay in hospital and risk of mortality did not change significantly over time. CONCLUSION: Patients' risk factors, except for CHF, did not change from 2000 to 2003. Despite more complicated procedures, the postoperative complication rates did not change except for a decrease in wound infections. These results suggest that the assumption of an inexorably increasing patient risk profile should be re-evaluated.

Does clopidogrel increase blood loss following coronary artery bypass surgery?

BACKGROUND: Clopidogrel (Plavix) is a potent inhibitor of platelet aggregation used concomitantly with percutaneous coronary interventions and in patients with acute coronary syndromes. Its favorable effects on preventing thrombus formation may have deleterious effects on hemostasis in patients undergoing coronary surgery. METHODS: Data were collected prospectively on 312 consecutive urgent or emergent coronary artery bypass patients from July 1999 through April 2001 at a tertiary care center. Patients were stratified into three groups: clopidogrel within 4 days of operation (n = 41), clopidogrel continued until 5 to 8 days before operation (n = 39), and clopidogrel discontinued more than 8 days before operation or were never taking clopidogrel (n = 232). RESULTS: Preoperative and intraoperative characteristics were similar among all groups. Mediastinal and pericardial chest tube losses in the first 24 hours were 1,044 +/- 750 mL in the clopidogrel within 4 days group, 528 +/- 250 mL in the clopidogrel 5 to 8 days group, and 573 +/- 329 mL in the clopidogrel more than 8 days group (p < 0.01). The mean total blood product transfusions were 12.2 +/- 15.4 U, 1.2 +/- 2.0 U, and 2.6 +/- 5.7 U, respectively (p < 0.001). Reoperation for bleeding was noted in 14.6%, 2.6%, and 1.7%, respectively (p = 0.002). The median hospital lengths of stay for the three groups were 9 days, 7 days, and 7 days, respectively (p = 0.018). There were no statistically significant differences in mortality rate, myocardial infarction, stroke, mediastinitis, or postoperative renal failure among the groups. Multivariable analysis revealed that clopidogrel within 0 to 4 days of operation was an independent predictor of transfusion requirements (OR 4.22, 95% confidence interval [CI] 2.07, 9.34, p = 0.001), intensive care unit (ICU) length of stay (OR 3.14, 95% CI 1.40, 7.04, p = 0.006), and total hospital length of stay (coefficient 7.65, se 2.41, p = 0.002). CONCLUSIONS: Clopidogrel within 4 days of coronary bypass surgery is associated with increased blood losses and reoperation for bleeding and, according to multivariable models, is an independent risk factor for increased transfusion requirements and prolonged ICU and hospital length of stay.

Is obesity a predictor of mortality, morbidity and readmission after cardiac surgery?

INTRODUCTION: Obesity has been described as a risk factor for the development of coronary artery disease, but it has not been determined whether obesity is associated with adverse outcomes after cardiac surgery. Therefore, we analyzed a large cohort of patients who had undergone cardiac surgery to determine whether obesity is a predictor of mortality, morbidity or early readmission to hospital. METHODS: At the London Health Sciences Centre, an academic tertiary care centre, we prospectively entered data from the cardiac surgical database from July 1999 to April 2002. We collected data on 1310 consecutive, unselected patients who underwent cardiac surgery during that time. We assessed the degree of obesity using the body mass index (BMI), and we prospectively documented the occurrence of 10 major complications after surgery. They included stroke, reoperation for bleeding, life-threatening cardiac arrest or arrhythmia, new renal failure requiring dialysis, septicemia, mediastinitis, sternal dehiscence, respiratory failure, postoperative myocardial infarction and low cardiac output necessitating intra-aortic balloon pump use. Univariable and multivariable analyses were conducted to determine the factors associated with and predictive of postoperative death and major complications. RESULTS: An increased BMI did not increase the risk of early postoperative death. Furthermore, increased BMI was not a predictor of a patient experiencing any of the major complications, except sternal dehiscence. An increased BMI was associated with a higher likelihood of readmission to hospital within 30 days of discharge. CONCLUSION: Obesity was not associated with adverse outcomes after cardiac operations, aside from the increased risks of sternal dehiscence and early hospital readmission.

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

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 surgeon's 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 Fisher's 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.