What factors influence the results of coronary artery bypass grafting in aged patients?

AIM: Early and late results were studied in order to improve the indication for coronary artery bypass grafting (CABG) and to enhance METHODS: A total of 1 973 patients aged 70 years and older who had undergone isolated CABG were studied. Elective operations (EL) were performed in 1 716 patients and 257 patients underwent urgent or emergency operations (UR/EM). Patients were divided into two groups; 104 patients aged 80 years and older (Oct. Group) and 1 869 patients of septuagenarians (Sept. Group). There were no differences between the groups in the number of diseased vessels. RESULTS: Total operative mortality rates in the Oct. and the Sept. groups were 7% and 4%, respectively. The operative mortality of elective surgery was 4% in both groups. The operative mortality of UR/EM CABG was significantly higher in the Oct. group than in the Sept. group (21% vs 6%). Operative mortality was significantly higher in patients with preoperative poor (<49%) left ventricular ejection fraction (LVEF) than in patients with higher (>50%) LVEF (6% vs 3%). Among preoperative risk factors, diabetes mellitus and peripheral vascular disease were significant contributory factors to operative death. In the follow-up study, 70% patients of the Oct. group and 72% patients of the Sept. group survived. Preoperative number of diseased vessels and number of CABG grafts did not influence the early and late CONCLUSION: Preoperative poor LVEF, diabetes mellitus and peripheral vascular disease were significant contributory factors to operative death. When feasible, CABG in octogenarians should be performed electively.

Amiodarone versus bretylium for suppression of reperfusion arrhythmias in dogs.

Reperfusion arrhythmias are an important complication of interventions to limit infarct size. Recently, amiodarone has been shown to be rapidly effective in suppressing sustained, incessant ventricular tachycardia and ventricular fibrillation in this setting. This study evaluated the time course of arrhythmia suppression and comparative efficacy of amiodarone versus bretylium in a canine model of reperfusion arrhythmias. Of 23 dogs subjected to a Harris two-stage coronary artery ligation followed by release, 18 demonstrated clinically significant ventricular arrhythmias and received either intravenous amiodarone, 5 mg/kg (9 dogs), or intravenous bretylium, 5 mg/kg (9 dogs). Direct-current shocks for sustained ventricular tachycardia or ventricular fibrillation were administered as necessary. Amiodarone rapidly suppressed sustained ventricular tachycardia and ventricular fibrillation in this model with no dog in the amiodarone-treated group requiring cardioversion after completion of the 15-minute infusion versus 4 of 9 dogs in the bretylium-treated group (p less than 0.05). Amiodarone was more effective than bretylium in suppressing episodes of sustained ventricular tachycardia/ventricular fibrillation, episodes of nonsustained ventricular tachycardia, and premature ventricular complexes. The blood pressure and heart rate decreased more after amiodarone administration than after bretylium administration. We conclude that, in the canine reperfusion arrhythmia model, amiodarone is rapidly effective in suppressing ventricular arrhythmias and is more effective than bretylium.

Pattern and significance of cerebral microemboli during coronary artery bypass grafting.

BACKGROUND: Strokes that occur during coronary artery bypass grafting are often caused by embolism. Intraoperative transcranial Doppler monitoring can detect cerebral microemboli. The aims of this study were to identify the pattern of microembolic phenomena during various stages of coronary artery bypass grafting, to verify whether numbers of high-intensity transient signals correlated with early neuropsychologic deficits, and to identify, using magnetic resonance imaging scans, whether radiologic evidence of cerebral infarction correlated with microembolic numbers during the bypass period. METHODS: Forty-one consecutive patients undergoing coronary bypass grafting with transcranial Doppler monitoring were enrolled in this study. All had preoperative and postoperative magnetic resonance imaging brain scans. A subgroup of 32 patients were studied by comparing microembolic load and early neuropsychological outcomes. RESULTS: Transcranial Doppler monitoring confirmed that most microemboli occurred during cardiopulmonary bypass. A significant early neuropsychological deficit after coronary artery bypass grafting did correspond to the total microembolic load during bypass (p = 0.008). However, patients with cerebral infarction on magnetic resonance imaging had significantly more microembolic signal during the preincision phases and not during the bypass period. CONCLUSIONS: Microembolic load during bypass is associated with early neuropsychologic deficits. In contrast, patients who show evidence of strokes during coronary artery bypass grafting have a higher microembolic load during the preincision phase than those without cerebral infarction. Differing mechanisms may be responsible for these different outcomes.

Prediction of outcome after revascularization in patients with poor left ventricular function.

BACKGROUND: In patients with poor left ventricular function, the determinants of outcome after revascularization are unknown. METHODS: We studied prospectively 57 patients with stable coronary artery disease and poor left ventricular function (left ventricular ejection fraction, 0.28 +/- 0.04) who underwent coronary artery bypass grafting. Clinical variables were assessed as predictors of outcome in all patients, and preoperative stress thallium-201 scintigraphic data were analysed in 37 patients. RESULTS: The operative mortality was 1.7%. At 12 months after operation, 46 of the 49 survivors were angina-free and 35 had fewer heart failure symptoms, but postoperative left ventricular ejection fraction (0.30 +/- 0.09) did not change significantly. Eighteen survivors had left ventricular ejection fraction improved by 0.05 or more (0.30 +/- 0.03 preoperatively, 0.40 +/- 0.05 postoperatively; p = 0.0001). The adjusted odds ratio of large reversible thallium-201 defects in predicting such outcome was 15 (95% confidence interval, 1.6 to 140), whereas other clinical variables had no predictive value. The transplantation-free 5-year survival was 73%. CONCLUSIONS: In patients with poor left ventricular function, surgical revascularization can be performed safely, with good symptomatic relief and long-term survival. One-year survival and improvement in left ventricular function is better in patients with large reversible defects on preoperative stress thallium-201 scintigraphy.

Early and intensive continuous hemofiltration for severe renal failure after cardiac surgery.

BACKGROUND: The aim of this study was to test whether early and intensive use of continuous venovenous hemofiltration (CVVH) achieved a better than predicted outcome in patients with severe acute renal failure undergoing cardiac operations, and whether a simple and yet accurate model could be developed to predict their outcome before starting CVVH. METHODS: Medical record analysis with collection of demographic, clinical, and outcome information was used. RESULTS: Sixty-five consecutive patients were treated with early and intensive CVVH (mean operation to CVVH time, 2.38 days; pump-controlled ultrafiltration rate, 2 L/h) after coronary artery bypass grafting (56.9%), single valve procedure (16.9%), or combined operations (26.2%). In 32.3% of patients, intraaortic balloon counterpulsation was required and 20% of patients were emergencies. Sustained hypotension despite inotropic and vasopressor support occurred in 40% of patients and prolonged mechanical ventilation in 58.5%. Using an outcome prediction score specific for acute renal failure, the predicted risk of death was 66%. Actual mortality was 40% (p = 0.003). Using multivariate logistic regression analysis and neural network analysis, patient outcome could be predicted with good levels of accuracy (receiver operating characteristic 0.89 and 0.9, respectively). CONCLUSIONS: Early and aggressive CVVH is associated with better than predicted survival in severe acute renal failure after cardiac operations. Using readily available clinical data, the outcome of such patients can be predicted before the implementation of CVVH.

An extracorporeal membrane oxygenation-based approach to cardiogenic shock in an older population.

BACKGROUND: We investigated the efficacy of an integrated system of advanced supportive care based on extracorporeal membrane oxygenation (ECMO) in older patients with an estimated mortality of more than 90% to establish whether its use is justifiable. METHODS: Treatment was provided by cardiac surgeons and critical care physicians and included the following key elements: (1) ECMO, (2) early application of continuous venovenous hemofiltration, (3) inhaled nitric oxide, (4) maintenance of perfusion pressure with norepinephrine, (5) maintenance of pulmonary blood flow by ventricular filling with intravenous colloids, (6) avoidance of early postoperative anticoagulation, (7) frequent use of transesophageal echocardiography, and (8) low tidal volume ventilation. Demographic features, intraoperative details, postoperative course, ECMO weaning rate, morbidity, survival to hospital discharge, and the quality of life of survivors were recorded. RESULTS: Seventeen consecutive patients (median age, 69 years) with refractory cardiogenic shock were studied. The median duration of ECMO was 86 hours (20 to 201 hours). Eleven patients (65%) were successfully weaned from ECMO. Seven patients (41%) survived to discharge. The major causes of morbidity were bleeding and leg ischemia. All patients who survived to discharge were alive and well at follow-up (median, 21 months) and reported a satisfactory quality of life. CONCLUSIONS: An ECMO-based approach can be used with acceptable results in the treatment of refractory cardiogenic shock, even in older patients.

The right internal thoracic artery graft--benefits of grafting the left coronary system and native vessels with a high grade stenosis.

OBJECTIVE: The left internal thoracic artery (LITA), when grafted to the left anterior descending artery (LAD), is generally accepted as the conduit of choice for coronary artery bypass grafting (CABG). In contrast, the role and efficacy of the right internal thoracic artery (RITA), despite its long-term use as a coronary artery graft, is relatively less understood. Accordingly, in this study, we sought to assess the utility of the RITA as a coronary conduit by examining the long-term patency of both in situ and free RITA grafts and analyzing the association between intraoperative graft and coronary artery variables. METHODS: Nine hundred and sixty-two patients (LITA 962, RITA 432) who had CABG between 1985 and 1998 and underwent re-angiography for evidence of myocardial ischemia were included in this observational analysis. The diameter of the internal thoracic artery (ITA), the presence of a proximal anastomosis with the aorta, the location of the anastomosis with the coronary artery, and the coronary artery diameter, were recorded at the initial procedure. The follow-up was 67.0+/-39.4 months (mean+/-SD, range 0.1-169.5). The relationship between intraoperative variables and graft patency was assessed using Cox proportional hazard models. RESULTS: Highest RITA failure rates were associated with grafting a native coronary artery with a stenosis of less than 60% compared with 80-100% (RR 3. 8 (95% CI, 1.9-7.2) P=0.0001). Grafts to non-LAD arteries had a higher risk of failure, the highest risk ratio being associated with grafting the right coronary artery (RR 4.0 (95% CI, 0.9-17.4) P=0.06)). Free compared with in situ grafts were also associated with a higher risk of failure with this result bordering on statistical significance (RR 1.9 (95% CI, 1.0-6.0) P=0.06)) CONCLUSION: Preference should be given to grafting arteries with a high grade stenosis or occlusion, to grafting left rather than right coronary arteries, and to using in situ rather than free ITA grafts. Passing the RITA to the left, either anterior to the aorta or through the transverse sinus, did not influence patency.

Early and late results of combined mitral-aortic valve surgery.

OBJECTIVE: This retrospective study was designed to assess the early morbidity and mortality as well as long-term mortality of combined aortic-mitral valve procedures at a single centre. METHODS: Patients were identified by analysing the intensive care and perfusion databases, from 1989 to 2003, with 113 receiving aortic-mitral valve procedures. Eighty-four percent of patients received a mechanical bileaflet valve. Survival was assessed using a Kaplan-Meier method, and determinants of survival with the Cox proportional hazards model. RESULTS: There were 57 men and 56 women, median age 59 (18-84) years. The 30-day mortality was 9% (n=10). This cohort contained a number of high risk patients, 38% were classified as New York Heart Association class IV, 33.5% had at least moderate ventricular impairment, 20% were redo procedures and 17% urgent procedures. Survival estimates at 5 and 10 years were 85% (0.76-0.90) and 65% (0.49-0.77), respectively. Multivariate pre-operative predictors of death included renal dysfunction (creatinine >200 micromol/L) and hypertension. Rheumatic aetiology was associated with improved survival. CONCLUSION: This study shows acceptable short and long-term survival in patients undergoing combined aortic-mitral valve surgical procedures at a single centre. Renal impairment and hypertension were associated with a poorer long-term prognosis and rheumatic aetiology was associated with improved survival. Age, LVEF and NYHA class were not associated with a worse outcome. This may affect future decision making in light of an aging population.

The use of parenteral nutrition in the management of external gastrointestinal tract fistulae.

Malnutrition is common in patients with gastrointestinal tract fistula, and is an important cause of the high mortality seen with this surgical complication. A prospective review of three years' experience in the management of fistulae with parenteral nutrition was undertaken, and the results obtained were compared with those in a group of patients treated prior to the introduction of this form of therapy. The use of parenteral nutrition resulted in a reduction of the mortality from 63% to 23% in unselected cases. The mortality was zero where parenteral nutrition was used in patients under 65 years of age with non-malignant disease. With parenteral nutrition therapy, the fistulae in almost all cases closed spontaneously, in contrast with a high proportion requiring operation (20 in 38 cases) where parenteral nutrition was not used. It is concluded that all patients with significant gastrointestinal fistula should be given appropriate parenteral nutrition as their prime mode of therapy.

Extracorporeal membrane oxygenation in pregnancy.

We describe the use of extracorporeal membrane oxygenation in pregnancy. There were no major complications, and the outcome was successful for mother and baby.

Concomitant coronary revascularization and resection of lung cancer.

As age and smoking are common risk factors, patients with lung cancer frequently have coexistent ischaemic heart disease. Ignoring the coronary disease results in an unacceptable operative mortality, whilst sequential coronary grafting and lung resection may prejudice the results of the resection. A series of 10 patients underwent combined coronary revascularization (average 2.9 grafts per patient) and lung resection for carcinoma (seven lobectomies, one bilobectomy, one sleeve lobectomy, and one pneumonectomy). The majority of patients had unstable angina, triple vessel or left main coronary artery stenosis and poorly staged tumours. There was no operative mortality and the average hospital stay was 20 days. Half the patients had significant peri-operative morbidity; seven are alive and well at between 12 and 38 months follow-up; but three have died of recurrent carcinoma (one with associated sepsis) at 3, 8, and 13 months. Combined coronary revascularization and lung resection can be safely performed in selected patients. The early morbidity is mainly related to the cardiac procedure and impaired respiratory function preoperatively, but the long-term results are dependent upon the control of the lung carcinoma.

Management of a patient with a complete rupture of a main bronchus in a community hospital.

We describe the successful use of a portable extracorporeal membrane oxygenation machine for a patient with complete rupture of the left main bronchus after a road crash. The machine was used before and during left main bronchus reanastomosis at a community hospital 30 km from Melbourne, and then during acute interhospital transfer.

The intraoperative assessment of ascending aortic atheroma: epiaortic imaging is superior to both transesophageal echocardiography and direct palpation.

OBJECTIVES: To determine the optimal method for detecting ascending aortic atheroma intraoperatively by comparing manual palpation by the operating surgeon, intraoperative transesophageal echocardiography, and epiaortic ultrasound (linear and phased-array imaging); and to assess risk factors for severe aortic atheroma. DESIGN: A longitudinal prospective study. Assessment of the atheroma by manual palpation was blinded to the results of the ultrasound images. SETTING: The study was performed in a single university tertiary referral hospital. PARTICIPANTS: One hundred consecutive patients undergoing coronary bypass or valve surgery were studied after their written, informed consent. INTERVENTIONS: Potential risk factors were evaluated by both a patient questionnaire and examination of prior hospital records. The ascending aorta was assessed by the following methods: manual palpation by the operating surgeon, intraoperative transesophageal echocardiography, and epiaortic ultrasound (linear and phased-array imaging) performed by an echocardiologist. For analysis, the ascending aorta was divided into three equal segments: proximal, mid, and distal, corresponding to regions of different operative manipulations. MEASUREMENTS AND MAIN RESULTS: Age older than 70 years and hypertension were significant risk factors for severe ascending aortic atheroma with adjusted odds ratios of 3.3 (95% CI, 1.2 to 9.3) and 3.9 (95% CI, 1.3 to 12.0), respectively. There was no significant difference in atheroma detection between the two ultrasonic epiaortic probes in any segment; however, epiaortic probes were superior to manual palpation in all segments and also superior to transesophageal echocardiography in the mid and distal segments of the ascending aorta. CONCLUSIONS: Age older than 70 years and hypertension are significant risk factors for severe ascending aortic atheroma. Intraoperative detection of ascending aortic atheroma is best achieved by epiaortic ultrasound with either a linear or phased array transducer. Transesophageal echocardiography is an insensitive technique for evaluation of mid and distal ascending aortic atheroma and, therefore, of little value in guiding surgical manipulations such as cross-clamping.