Hemodynamic differences between the awake and anesthetized conditions in normal calves.

There is insufficient information in the literature about baseline circulatory parameters in normal calves in the anesthetized versus postoperative awake conditions under which a large volume of medical research is conducted. Eleven calves (mean body weight, 78.1 ± 14.3 kg) were implanted with a flow probe and fluid-filled pressure lines to measure cardiac output (CO), aortic (AoP), central venous (CVP), pulmonary arterial (PAP), and left atrial pressures (LAP). Systemic (SVR) and pulmonary vascular resistance (PVR) were also calculated. We obtained the above hemodynamic data (n = 11) and epicardial echocardiography (n = 7) during open-chest surgery under isoflurane anesthesia. After full recovery from surgery, animals were evaluated in the awake condition on postoperative days 6-9 using transthoracic echocardiography (n = 7) and the hemodynamic monitoring lines and probes noted (n = 11). CO, AoP, and PAP levels in the anesthetized condition were significantly lower than in the awake condition. Other hemodynamic parameters (CVP, LAP, SVR, and PVR) were not significantly different. In conclusion, data from this study quantify changes in CO, AoP, and PAP in anesthetized calves that may affect the hemodynamic response to experimental therapeutics such as new cardiac assist devices, prosthetic valves, and surgical interventions. Our study also provides baseline data for the translation of the hemodynamic data obtained in acute in vivo calf studies to that of an awake subject.

Endoscopic versus open radial artery harvesting for coronary artery bypass grafting.

BACKGROUND AND AIM OF THE STUDY: The radial artery has become the artery of choice after both internal thoracic arteries for coronary artery bypass grafting (CABG). This study compares wound healing and arm complications after endoscopic versus open radial artery harvesting. METHODS: From January 2002 to July 2004, 509 patients underwent CABG including a radial artery conduit. Thirty-nine had endoscopic and 470 conventional open radial artery harvesting. A propensity score was used to obtain 1:3 matching of all endoscopic to 117 open-harvesting patients. Postoperative wound healing, local neurologic deficits, wound infection, and pain scores were compared. RESULTS: Wound healing: 34 of 39 endoscopic wounds exhibited a perfect Hollander score versus 339 of 470 open-harvest wounds (p = 0.01). Wound appearance was better for endoscopic harvesting (p = 0.004). Three incomplete neurologic deficits were observed after open harvesting versus one complete neurologic deficit after endoscopic harvesting that recovered prior to hospital discharge. Incidence of wound infection was similar in both groups (p = 0.7), although infection was more severe with open harvesting. Pain score was lower (p = 0.006) with endoscopic harvesting. CONCLUSIONS: Endoscopic radial artery harvesting was associated with better wound appearance and less pain. Occurrence of neurologic deficits and wound infection was infrequent in both groups.

Implantation technique and early echocardiographic performance of newly designed stentless mitral bioprosthesis.

This article describes the implantation techniques of two new stentless mitral bioprosthesis and their early echocardiographic performance in 12 acute sheep model. The first stentless mitral bioprosthesis (stentless bileaflet valve [SBV]) was designed as a bileaflet valve with sewing ring to suture down to the native mitral annulus. The other one (SBV with chordae) has two chordae-like structures to be attached to the head of the native papillary muscles. Valvar performance and cardiac function were evaluated by epicardial echocardiography at postimplant (Rest) and during dobutamine (DOB) stimulation. Postimplant echocardiography revealed normal leaflet opening with a large orifice area and unrestricted leaflets motion. In both valves, leaflet closure showed no systolic anterior motion, prolapse, or tethering. Mitral regurgitation grade 2 or higher was not detected in any of the experiments. Transvalvar pressure gradients at Rest and DOB were 2.3 ± 1.6 mm Hg and 2.5 ± 2.2 mm Hg in SBV and 1.8 ± 1.1 mm Hg and 2.3 ± 1.2 mm Hg in SBV with chordae, respectively. Both stentless bioprosthesis showed reliable valve performance and preserved cardiac function in the acute phase. Further chronic study is needed to evaluate the reliability of implantation procedures, valvar performance, and biocompatibility.

The first Latin-American risk stratification system for cardiac surgery: can be used as a graphic pocket-card score.

This study aims to develop the first Latin-American risk model that can be used as a simple, pocket-card graphic score at bedside. The risk model was developed on 2903 patients who underwent cardiac surgery at the Spanish Hospital of Buenos Aires, Argentina, between June 1994 and December 1999. Internal validation was performed on 708 patients between January 2000 and June 2001 at the same center. External validation was performed on 1087 patients between February 2000 and January 2007 at three other centers in Argentina. In the development dataset the area under receiver operating characteristics (ROC) curve was 0.73 and the Hosmer-Lemeshow (HL) test was P=0.88. In the internal validation ROC curve was 0.77. In the external validation ROC curve was 0.81, but imperfect calibration was detected because the observed in-hospital mortality (3.96%) was significantly lower than the development dataset (8.20%) (P<0.0001). Recalibration was done in 2007, showing excellent level of agreement between the observed and predicted mortality rates on all patients (P=0.92). This is the first risk model for cardiac surgery developed in a population of Latin-America with both internal and external validation. A simple graphic pocket-card score allows an easy bedside application with acceptable statistic precision.

Economic evaluation of coronary artery bypass grafting surgery with and without cardiopulmonary bypass: cost-effectiveness and quality-adjusted life years in a randomized controlled trial.

The objective of this study is to evaluate the costs and health benefits of coronary artery bypass grafting (CABG) surgery with and without cardiopulmonary bypass (CPB). Randomized controlled clinical trial is used as the design. The setting is in a single tertiary cardiothoracic center in Middlesex, UK. Participants were 168 patients (27 females) requiring primary isolated CABG surgery. Patients were randomized to have the procedure performed by a single surgeon either with CPB (n = 84) or by an off-pump coronary artery bypass (OPCAB) surgery (n = 84). Health-related quality of life was assessed at baseline, 6 weeks, and 6 months using the World Health Organization Quality-of-Life (WHOQOL-100) questionnaire. Mean total costs of patient management by either technique were calculated using different available key sources. A utility measure, derived from WHOQOL-100, was used to calculate quality-adjusted life year (QALY) gained in each group, on basis of which a cost-effectiveness analysis was performed. The mean total costs of an OPCAB patient was 5859 pounds , whereas for a CPB patient it was 7431 pounds with a mean difference of 1572 pounds (standard error [SE] 674 pounds ; P = 0.02). Three patients died in the CPB group and two in the OPCAB group during the 6-month follow-up period. Mean QALYs over 6 months was 0.379 in the OPCAB group and 0.362 in the CPB group, but the difference was not significant (mean difference 0.017; SE 0.016; P = 0.305). OPCAB surgery offered patients in this randomized trial similar health benefits to CPB over a 6-month period, but at a significantly less cost.

Objective surgical skill assessment: the diagonal operating matrix.

There is an urgent need for structured surgical training and assessment due to the reduction in the training duration with the European Working Time Directive (EWTD). We propose a model for objective skill assessment, the PAR-Diagonal Operating Matrix (PAR-DOM) which breaks down the task of vascular anastomosis into clearly defined skills. The PAR-DOM is made up of a 3x5 table and progress is made along vectors defined on the x-axis as PAR and on the y-axis as four levels. PAR defines three skills at each level. Each skill is graded from 1-3 (this may be taken as below average, average, above average). The skills at various levels are: Level 0 - Posture, Address, Relaxation; Level 1 - Pick-up, Airtime, Rotation; Level 2 - Placing, Angles, Rhythm; Level 3 - Precision, Adaptability, Reproducibility; Level 4 - Pace, Awareness, Relations. The PAR-DOM matrix provides a graphic representation of the progress of trainees over their training period assigned for them to stay with the trainer and also help identify individual strengths and weaknesses.

A three-dimensional echocardiographic comparison of a deep pericardial stitch versus an apical suction device for heart positioning during beating heart surgery.

BACKGROUND: Heart positioning during beating heart surgery produces significant haemodynamic compromise either when a deep pericardial stitch (DPS) or apical suction devices (ApSDs) are used. In this study the two techniques' haemodynamic performance and effect on intracardiac structures were compared through transoesophageal echocardiography (TEE) obtained volume measurements and three-dimensional ventricular and mitral valve computer reconstructions. METHODS: Sequential 0 degrees to 180 degrees TEE images of the left heart were obtained in 10 patients undergoing beating heart surgery. Measurements with both techniques in three different positions were obtained: at baseline, the heart elevated to access its inferior surface and the heart elevated and rotated to access its lateral surface. Three-dimensional computer reconstructions of the mitral valve and the left heart were generated. Ventricular volume measurements were used to calculate stroke volume, ejection fraction and differences from baseline. An analysis of variance between each technique in all three positions was performed. RESULTS: Central venous, left atrial and pulmonary artery pressures were significantly increased with either technique during positioning. Both techniques significantly affected left ventricular function decreasing stroke volume and ejection fraction. In the vertical and rotated position, the ApSD produced a significant decrease from baseline both in stroke volume (DPS: 32.8+/-18.7 vs ApSD: 55.46+/-21.7; p=0.02) and in ejection fraction (DPS: 19.3+/-10.5 vs ApSD: 40.9+/-24.6; p=0.02). The three-dimensional reconstructions demonstrated significant distortion of the atrioventricular geometry and the mitral valve, which was more pronounced with the DPS. CONCLUSION: Both techniques produce variable degrees of deformation with associated cardiac dysfunction and haemodynamic instability. Cardiac function is impeded more with an ApSD with the heart elevated and rotated.

Comparison of clinical and economic outcomes of two antibiotic prophylaxis regimens for sternal wound infection in high-risk patients following coronary artery bypass grafting surgery: a prospective randomised double-blind controlled trial.

OBJECTIVE: Prospective studies show a 10% incidence of sternal wound infection (SWI) after 90 days of follow-up, compared with infection rates of 5% reported by the National Nosocomial Infections Surveillance System after only 30 days of follow-up. This incidence increases 2-3 times in high-risk patients. DESIGN: Prospective randomised double-blind controlled clinical trial. SETTING: Cardiothoracic centre, UK. PATIENTS: Patients were eligible if they were undergoing median sternotomy for primary isolated coronary artery bypass grafting, with at least one internal thoracic artery used for coronary grafting and having one or more of the following three risk factors: (1) obesity, defined as body mass index 30 kg/m(2); (2) diabetes mellitus; or (3) bilateral internal thoracic artery grafts (ie, the use of the other internal thoracic artery). INTERVENTIONS: The study group received a single dose of gentamicin 2 mg/kg, rifampicin 600 mg and vancomycin 15 mg/kg, with three further doses of 7.5 mg/kg at 12-hour intervals. The control group received cefuroxime 1.5 g at induction and three further doses of 750 mg at 8-hour intervals. MAIN OUTCOME MEASURES: The primary end point was the incidence of SWI at 90 days. The secondary end point was the antibiotic and hospital costs. RESULTS: During the study period, 486 patients underwent isolated coronary artery bypass grafting with a 30-day SWI of 7.6%. 186 high-risk patients were recruited and analysed: 87 in the study group and 99 in the control group. 90-day SWI was significantly reduced in 8 patients in the study group (9.2%; 95% CI 3.5% to 15.3%) compared with 25 patients in the control group (25.2%; 95% CI 19.5% to 39.4%; p = 0.004). The study group had a significantly lower cost of antibiotics (21.2% reduction--US$96/patient; p<0.001), and a significantly lower hospital cost (20.4% reduction in cost--US$3800/patient; p = 0.04). CONCLUSIONS: Longer and broader-spectrum antibiotic prophylaxis significantly reduces the incidence of SWI in high-risk patients, with a significant economic benefit in costs of antibiotics as well as hospital costs.

Systemic venous thrombosis after recombinant factor VIIa in the control of bleeding after cardiac surgery.

Recombinant factor VIIa has been licensed in the United Kingdom since 1996 for the control of bleeding in hemophilic patients who are actively bleeding or are about to undergo surgery. Medical practitioners are also applying recombinant factor VIIa toward the control of bleeding in patients without hemophilia. Although the efficacy of recombinant factor VIIa has been shown in many patients, concerns have arisen about the risk of thrombotic adverse events. Herein, we report the case of a 73-year-old woman who underwent major coronary surgery and developed fatal systemic venous thrombosis after recombinant factor VIIa was used in an attempt to control her severe postoperative bleeding. We review the medical literature and discuss the risks of using recombinant factor VIIa to control severe bleeding after cardiac surgery.

Effect of off-pump coronary artery bypass surgery on clinical, angiographic, neurocognitive, and quality of life outcomes: randomised controlled trial.

OBJECTIVE: To compare the clinical, angiographic, neurocognitive, and quality of life outcomes of off-pump coronary artery bypass surgery with conventional coronary artery bypass grafting surgery using cardiopulmonary bypass. DESIGN: Randomised controlled clinical trial. SETTING: Tertiary cardiothoracic centre in Middlesex, England. PARTICIPANTS: 168 patients (27 women) requiring primary isolated coronary artery bypass grafting surgery. INTERVENTIONS: Patients were randomised to conventional coronary artery bypass grafting surgery using cardiopulmonary bypass (n = 84) or off-pump coronary artery bypass surgery (n = 84), carried out by one surgeon. Angiographic examination was carried out at three months postoperatively. Neurocognitive tests were carried out at baseline and at six weeks and six months postoperatively. MAIN OUTCOME MEASURES: Clinical outcome, graft patency at three months, neurocognitive function at six weeks and six months, and health related quality of life. RESULTS: Graft patency was evaluated by angiography in 151 (89.9%) patients and was similar between the cardiopulmonary bypass and off-pump groups (risk difference - 1%, 95% confidence interval - 5% to 4%), with the off-pump group considered the treatment group. Patients in the off-pump group required fewer blood transfusions (1.7 units v 1.0 unit, P = 0.02), shorter duration of mechanical ventilation (7.7 hours v 3.9 hours, P = 0.03), and shorter hospital stay (10.8 days v 8.9 days). Scores for neurocognitive function showed a significant difference in three memory subtests at six weeks and two memory subtests at six months in favour of the off-pump group. CONCLUSIONS: Patients who underwent off-pump coronary artery bypass surgery showed similar patency of grafts, better clinical outcome, shorter hospital stay, and better neurocognitive function than patients who underwent conventional coronary artery bypass grafting surgery using cardiopulmonary bypass.