Fuad Moussa

Does the Use of Preoperative Aspirin Increase the Risk of Bleeding in Patients Undergoing Coronary Artery Bypass Grafting Surgery? Systematic Review and Meta-Analysis

Abstract  Background: The traditional recommendation has been to stop Aspirin seven to 10 days prior to coronary artery bypass surgery to reduce the potential risk of bleeding. A few reports have shown that Aspirin did not increase the risk of bleeding and may be beneficial to be continued until the time of surgery. The objective of this review was to evaluate the effect of preoperative Aspirin on bleeding in patients undergoing elective bypass surgery. Methods: A meta‐analysis of 10 randomized and nonrandomized studies reporting comparisons between Aspirin and control was undertaken. The primary outcome was the total amount of postoperative chest tube drainage. Secondary outcomes were the number of units of packed red blood cell transfusion, platelet transfusion, fresh frozen plasma transfusion, and number of patients reexplored for bleeding. Results: Ten studies, involving 1748 patients, met the inclusion criteria for this review of whom 913 were in the Aspirin group and 835 were in the control group. Pooling the results of all studies showed a significant increase in blood loss and transfusion of red blood cells and fresh frozen plasma in the Aspirin group (p < 0.05). There was no significant difference between the two groups in the rate of platelet transfusion, or the incidence of reexploration (p > 0.05). Included studies were heterogeneous and of low methodological quality. Conclusion: Aspirin is associated with increased chest tube drainage and may be associated with a greater requirement for blood products. High‐quality prospective studies are warranted to reassess the effect of Aspirin on important postoperative outcomes.

Troponin after cardiac surgery: a predictor or a phenomenon?

BACKGROUND Increased cardiac troponin is observed after virtually every cardiac operation, indicating perioperative myocardial injury. The clinical significance of this elevation is controversial. This study aimed to correlate postoperative troponin levels with major adverse cardiac events (MACE). METHODS The study included 1918 consecutive patients undergoing adult cardiac operations, including 1515 isolated coronary procedures, 229 valvular operations, and 174 combined coronary/valve procedures. Peak troponin T (normal value < 0.1 microg/L) was measured at less than 24 hours postoperatively. Excluded were 506 patients with a recent myocardial infarction (< 30-days of operation). The primary outcome was a composite of death, electrocardiogram-defined infarction, and low output syndrome (MACE). RESULTS Mortality rates were 1.4%, 6.1%, and 7% in the coronary bypass, valve, and combined groups, respectively (p < 0.001). The rates of MACE were 17%, 35%, and 44% (p < 0.0001), and mean troponin T levels were 0.9 +/- 1.5, 1.2 +/- 2.9, and 1.3 +/- 1.2 microg/L (p < 0.001), in the coronary bypass, valve, and combined groups, respectively. All patients were divided into quintiles based on their peak postoperative troponin level (Q1, 0.0 to 0.39; Q2, 0.4 to 0.59; Q3, 0.6 to 0.79; Q4, 0.8 to 1.29; and Q5, > 1.3 microg/L). Adverse outcomes were similar and stable in the lower quintiles. A stepwise increase in adverse outcomes was observed in the higher quintiles. Receiver operating characteristic curve analysis revealed a troponin cutoff of 0.8 microg/L was the most discriminatory for MACE (area under the curve, 0.7). Multivariable analyses showed a troponin value of more than 0.8 microg/L was independently associated with MACE. CONCLUSIONS Moderate elevations in troponin are common after cardiac operations; troponin is a well-described predictor of outcomes. Troponin levels exceeding 0.8 microg/L are associated with increased MACE in patients without a history of preoperative myocardial infarction within 30 days of operation.

Are stentless valves hemodynamically superior to stented valves? Long-term follow-up of a randomized trial comparing Carpentier–Edwards pericardial valve with the Toronto Stentless Porcine Valve

OBJECTIVE The benefit of stentless valves remains in question. In 1999, a randomized trial comparing stentless and stented valves was unable to demonstrate any hemodynamic or clinical benefits at 1 year after implantation. This study reviews long-term outcomes of patients randomized in the aforementioned trial. METHODS Between 1996 and 1999, 99 patients undergoing aortic valve replacement were randomized to receive either a stented Carpentier-Edwards pericardial valve (CE) (Edwards Lifesciences, Irvine, Calif) or a Toronto Stentless Porcine Valve (SPV) (St Jude Medical, Minneapolis, Minn). Among these, 38 patients were available for late echocardiographic follow-up (CE, n = 17; SPV, n = 21). Echocardiographic analysis was undertaken both at rest and with dobutamine stress, and functional status (Duke Activity Status Index) was compared at a mean of 9.3 years postoperatively (range, 7.5-11.1 years). Clinical follow-up was 82% complete at a mean of 10.3 years postoperatively (range, 7.5-12.2 years). RESULTS Preoperative characteristics were similar between groups. Effective orifice areas increased in both groups over time. Although there were no differences in effective orifice areas at 1 year, at 9 years, effective orifice areas were significantly greater in the SPV group (CE, 1.49 +/- 0.59 cm(2); SPV, 2.00 +/- 0.53 cm(2); P = .011). Similarly, mean and peak gradients decreased in both groups over time; however, at 9 years, gradients were lower in the SPV group (mean: CE, 10.8 +/- 3.8 mm Hg; SPV, 7.8 +/- 4.8 mm Hg; P = .011; peak: CE, 20.4 +/- 6.5 mm Hg; SPV, 14.6 +/- 7.1 mm Hg; P = .022). Such differences were magnified with dobutamine stress (mean: CE, 22.7 +/- 6.1 mm Hg; SPV, 15.3 +/- 8.4 mm Hg; P = .008; peak: CE, 48.1 +/- 11.8 mm Hg; SPV, 30.8 +/- 17.7 mm Hg; P = .001). Ventricular mass regression occurred in both groups; however, no differences were demonstrated between groups either on echocardiographic, magnetic resonance imaging, or biochemical (plasma B-type [brain] natriuretic peptide) assessment (P = .74). Similarly, Duke Activity Status Index scores of functional status improved in both groups over time; however, no differences were noted between groups (CE, 27.5 +/- 19.1; SPV, 19.9 +/- 12.0; P = .69). Freedom from reoperation at 12 years was 92% +/- 5% in patients with CEs and 75% +/- 5% in patients with SPVs (P = .65). Freedom from valve-related morbidity at 12 years was 82% +/- 7% in patients with CEs and 55% +/- 7% in patients with SPVs (P = .05). Finally, 12-year actuarial survival was 35% +/- 7% in patients with CEs and 52% +/- 7% in patients with SPVs (P = .37). CONCLUSION Although offering improved hemodynamic outcomes, the SPV did not afford superior mass regression or improved clinical outcomes up to 12 years after implantation.

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.

The Graft Imaging to Improve Patency (GRIIP) clinical trial results

OBJECTIVE This trial aimed to determine whether intraoperative graft assessment with criteria for graft revision would decrease the proportion of patients with 1 or more graft occlusions or stenoses or major adverse cardiac events 1 year after coronary artery bypass grafting. METHODS A single-center, randomized, single-blinded, controlled clinical trial was designed. Patients were randomized to either of 2 groups: intraoperative graft patency assessment using indocyanine-green fluorescent angiography and transit-time flowmetry, with graft revision according to a priori criteria (imaging group), or standard intraoperative management (control group). Patients underwent follow-up angiography at 1 year. RESULTS Between September 2005 and August 2008, 156 patients undergoing isolated coronary bypass grafting were enrolled (imaging, n = 78; control, n = 78). Demographic and angiographic characteristics were similar between groups. Operative, crossclamp, and cardiopulmonary bypass times were all nonsignificantly longer in the imaging arm. The number of grafts per patients was similar (imaging, 3.0 +/- 0.7; control, 3.0 +/- 0.7). The frequency of major adverse cardiac events (death, myocardial infarction, repeat revascularization) was not different between groups at 1 year postoperatively (imaging, 7.7%; control, 7.7%). One-year angiography was performed in 107 patients (imaging, 55 patients/160 grafts; control, 52 patients/152 grafts). The proportion of patients with 1 graft occlusion or more was comparable in the imaging (30.9%) and control (28.9%) groups (relative risk [95% confidence interval], 1.1 [0.6-1.9]; P = .82), as were other graft patency end points. The incidence of saphenous vein graft occlusion was high in both groups. CONCLUSIONS Routine intraoperative graft assessment is safe but does not lead to a marked reduction in graft occlusion 1-year after bypass grafting. The incidence of saphenous vein graft failure remains high despite contemporary practice and routine intraoperative graft surveillance.

Cut‐Off Values for Transit Time Flowmetry: Are the Revision Criteria Appropriate?

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.

Coronary Artery Bypass in the Context of Polyarteritis Nodosa

A 46-year-old man with polyarteritis nodosa and multiple myocardial infarctions treated with multiple percutaneous coronary interventions presented again with atypical angina. Coronary angiography revealed triple-vessel coronary artery disease. This patient underwent four-vessel coronary artery bypass graft and recovered uneventfully. A review of the literature and discussion of the surgical management of this patient is presented.

SCETF: Serious game surgical cognitive education and training framework

Surgical proficiency requires command of both technical and cognitive skills. Although at times overlooked, cognitive skills training allows residents to practise detecting errors ultimately leading to a reduction of errors. Virtual simulations and serious games offer a viable alternative to practice in an actual operating room where traditionally both technical and cognitive skills acquisition takes places. They provide residents the opportunity to train until they reach a specific competency level in a safe, cost effective, fun, and engaging manner allowing them to make more effective use of their limited training time in the operating room. Here we introduce a serious game surgical cognitive education and training framework (SCETF) that is currently being developed specifically for cognitive surgical skills training. Domain-specific surgical “modules” can then be built on top of the existing framework, utilizing common simulation elements/assets. The SCETF is being developed as a research tool where various simulation parameters such as levels of audio and visual fidelity, can be easily adjusted allowing for the controlled testing of such factors on knowledge transfer and retention.

An Overview of Virtual Simulation and Serious Gaming for Surgical Education and Training

The rising popularity of video games has seen a recent push towards the application of serious games to medical education and training. With their ability to engage players/learners for a specific purpose, serious games provide an opportunity to acquire cognitive and technical surgical skills outside the operating room thereby optimizing operating room exposure with live patients. However, before the application of serious games for surgical education and training becomes more widespread, there are a number of open questions and issues that must be addressed including the relationship between fidelity, multi-modal cue interaction, immersion, and knowledge transfer and retention. In this chapter we begin with a brief overview of alternative medical/surgical educational methods, followed by a discussion of serious games and their application to surgical education, fidelity, multi-modal cue interaction and their role within a virtual simulations/serious games. The chapter ends with a description of the serious games surgical cognitive education and training framework (SCETF) and concluding remarks.

Effects of sound on visual realism perception and task performance

Before the application of virtual simulations and serious games for surgical education and training becomes more widespread, there are a number of open questions and issues that must be addressed including the relationship between realism, multi-modal cue interaction, immersion, and knowledge transfer and retention. Using the serious game surgical cognitive education and training framework developed specifically for cognitive surgical skills training, here we examine the effect of sound on visual realism perception and task completion time while performing a task within a virtual environment. Our preliminary experimental results indicate that the appropriate use of sound can lead to performance improvements when performing a task within a virtual environment without a corresponding decrease in the perception of visual realism.