Post Coronary Artery Bypass Surgery Research Articles

Thiazolidinediones associated with recurrent pleural effusions post coronary artery bypass surgery

We report the case of a patient in which thiazolidinediones (TZDs) were associated with recurrent pleural effusions post coronary artery bypass surgery, in spite of a normal left ventricular function. The potential mechanisms are discussed, particularly in relation to the “vascular leak syndrome”. This finding has important implications for the management of diabetic patients who are referred for coronary artery bypass surgery and who are on TZDs for glycemic control.

Long-term Effects of Cardiac Rehabilitation and the Paradigms of Cardiac Rehabilitation

The benefits of exercise training for postmyocardial infarction and postcoronary artery bypass surgery patients are well established, but little is known about the effects of rehabilitation in the months or years following the program. The purpose of this study was to assess exercise capacity, blood lipids, and physical activity patterns 2 years after completing a concentrated residential rehabilitation program in Switzerland. Seventy-eight patients (86% males, mean age = 56 +/- 10, mean ejection fraction = 64% +/- 12%) were referred to a residential rehabilitation program after a myocardial infarction or coronary artery bypass surgery between January 2001 and June 2001. Patients lived at the center for 1 month, during which time they underwent educational sessions, consumed a low-fat diet, and exercised 2 hours daily. Two years after completing the program, patients returned to the hospital and underwent a maximal exercise test, an assessment of recent and adulthood physical activity patterns, and evaluation of blood lipids. During the 2-year follow-up period, there were 5 deaths, and 70 of the remaining 73 patients returned for repeat testing. Mean exercise capacity increased 27% during the rehabilitation program (P < .01). Gains in exercise capacity during rehabilitation were maintained after the follow-up period; mean exercise capacity after 2 years was 34% higher compared with that at baseline (P < .01). At the 2-year evaluation, patients were expending a mean of 3127 +/- 1689 kcals/wk during recreational activities compared with 977 +/- 842 kcals/wk during adulthood prior to their cardiac event (P < .001). Between the completion of rehabilitation and the 2-year follow-up, total cholesterol, total cholesterol/high-density lipoprotein ratio, and triglycerides increased significantly. Two years after a cardiac event and participation in a concentrated residential rehabilitation program, patients maintained their exercise capacity and engaged in physical activities that exceed the levels recommended by guidelines for cardiovascular health. These observations suggest that a relatively intensive rehabilitation program provided a catalyst to maintain physical activity patterns and exercise tolerance in the 2 years following a cardiac event.

Co-existence of heparin-induced thrombocytopenia and thrombotic thrombocytopenic purpura in a postoperative cardiac surgery patient

Up to 50% of patients undergoing coronary artery bypass surgery will develop antibodies against the heparin-platelet factor 4 complex, and a small percentage of those will go on to develop heparin-induced thrombocytopenia. Thrombotic thrombocytopenic purpura has also been reported post-coronary artery bypass surgery. In this case report, we describe a patient who developed both heparin-induced thrombocytopenia and thrombotic thrombocytopenic purpura post-coronary artery bypass surgery. This patient had clinical features consistent with both entities, and the clinical picture could not be explained by either heparin-induced thrombocytopenia or thrombotic thrombocytopenic purpura alone. It is hypothesized that these two entities may be related in this patient population, and this case report emphasizes the challenges in the diagnosis of thrombocytopenia in this patient population.

Maintenance of Exercise Capacity and Physical Activity Patterns 2 Years After Cardiac Rehabilitation

The benefits of exercise training for postmyocardial infarction and postcoronary artery bypass surgery patients are well established, but little is known about the effects of rehabilitation in the months or years following the program. The purpose of this study was to assess exercise capacity, blood lipids, and physical activity patterns 2 years after completing a concentrated residential rehabilitation program in Switzerland. Seventy-eight patients (86% males, mean age = 56 +/- 10, mean ejection fraction = 64% +/- 12%) were referred to a residential rehabilitation program after a myocardial infarction or coronary artery bypass surgery between January 2001 and June 2001. Patients lived at the center for 1 month, during which time they underwent educational sessions, consumed a low-fat diet, and exercised 2 hours daily. Two years after completing the program, patients returned to the hospital and underwent a maximal exercise test, an assessment of recent and adulthood physical activity patterns, and evaluation of blood lipids. During the 2-year follow-up period, there were 5 deaths, and 70 of the remaining 73 patients returned for repeat testing. Mean exercise capacity increased 27% during the rehabilitation program (P < .01). Gains in exercise capacity during rehabilitation were maintained after the follow-up period; mean exercise capacity after 2 years was 34% higher compared with that at baseline (P < .01). At the 2-year evaluation, patients were expending a mean of 3127 +/- 1689 kcals/wk during recreational activities compared with 977 +/- 842 kcals/wk during adulthood prior to their cardiac event (P < .001). Between the completion of rehabilitation and the 2-year follow-up, total cholesterol, total cholesterol/high-density lipoprotein ratio, and triglycerides increased significantly. Two years after a cardiac event and participation in a concentrated residential rehabilitation program, patients maintained their exercise capacity and engaged in physical activities that exceed the levels recommended by guidelines for cardiovascular health. These observations suggest that a relatively intensive rehabilitation program provided a catalyst to maintain physical activity patterns and exercise tolerance in the 2 years following a cardiac event.

Lifestyle adaptation of the patient post coronary artery bypass surgery (CABG)

Lifestyle adaptation of the patient post coronary artery bypass surgery (CABG)

1P-0069 Percutaneous coronary interventions during the first year post-coronary artery bypass surgery

1P-0069 Percutaneous coronary interventions during the first year post-coronary artery bypass surgery

Assessment of new onset postcoronary artery bypass surgery atrial fibrillation: current practice pattern review and the development of treatment guidelines.

The incidence of postcoronary artery bypass graft (CABG) atrial fibrillation (AF) is 22.5% at the QEII Health Sciences Centre and the mean length of stay is 5.5 days greater than for those patients who do not experience this complication. Appropriate pharmacological management is important to prevent the potential morbidity from AF, such as thromboembolism, congestive heart failure, cardiogenic shock and coronary ischemia. This project compared current practice patterns in the management of post-CABG AF with local practice pattern beliefs and evidence from the primary literature. Subsequently, treatment guidelines were designed to help guide a rationale treatment approach. To promote appropriate treatment strategies for post-CABG AF and increase local practitioner awareness of drug-use outcomes by developing consensus treatment guidelines. There were three phases. In phase 1, a retrospective chart analysis of 35 post-CABG AF patients over three consecutive months was conducted to assess current practice patterns. All published studies on this subject were also collected and analysed. A survey of pharmacological treatment preferences was distributed to local stakeholders during phase 2. The third phase involved the development and implementation of treatment guidelines. This study identified a highly variable approach to the treatment of post-CABG AF. The mean number of agents used to treat AF post-CABG was two (range 1-4); all patients (100%) were prescribed rate-controlling agents and 37% were prescribed an antiarrhythmic drug. There was also a mismatch between practice pattern beliefs and actual practice. This reinforced the need for a consistent treatment approach that was facilitated with the development and implementation of local guidelines.

Morbidity of Post-Coronary Artery Bypass Surgery Patients with Atrial Fibrillation Treated with Rate Control versus Sinus-Restoring Therapy

Background: Atrial fibrillation (AF) is the most common dysrhythmia encountered in the post-coronary artery bypass (post-CABG) patient, reported to occur with a frequency of 20–40%. To date, with the exception of amiodarone, there is no evidence that prophylactic therapy or therapy to restore and maintain sinus rhythm reduces the risk of adverse events associated with AF. Objective: To determine whether rate control alone is an effective method of managing post-CABG AF. Method: Prospective nonrandomized observational pilot study to assess the outcome of patients with post-CABG AF managed with rate control (group 1) or a combination of rate control and sinus-restoring therapy (group 2). Adverse events, postoperative length of stay, and persistence of AF were assessed in both groups at discharge and 30 days post-discharge. Results: Post-CABG AF was observed in 101 patients. Among the 39 patients in group 1 and 62 patients in group 2, there was an 87% spontaneous conversion rate to sinus rhythm at discharge (p = 0.99). The surgical length of stay was 6.3 days in group 1, and 8.3 days in group 2 (p = 0.01). Adverse events were observed in 2 patients (5.1%) in group 1, and 7 patients (11.3%) in group 2 (p = 0.29). Conclusion: Rate control appears to be an effective method of management of post-CABG AF patients, reducing length of hospital stay without increasing the rate of adverse events. Similar proportions of patients from both groups were in sinus rhythm at time of discharge, irrespective of therapeutic techniques.

Lipid-lowering therapy after coronary revascularization

Atherosclerosis is often asymptomatic, unrecognized, and undertreated. Lumen irregularities are important angiographic findings that should be addressed aggressively through risk factor modification, medical therapy, and coronary revascularization. Both angiographic and clinical benefits have been demonstrated with lipid reduction therapy in randomized clinical trials. Coronary revascularization is indicated for symptom relief and improvement in quality of life in patients with acute coronary syndromes at “intermediate” and “high” risk of subsequent death or myocardial infarction. In patients following percutaneous coronary intervention (PCI), future cardiac events may be related to lumen renarrowing or to progression of atherosclerotic disease at sites remote from the site of coronary revascularization. The time course of restenosis is relatively self-limiting, generally occurring within 6–12 months after the procedure. Clinical events occurring >1 year after PCI generally relate to new lesions or progression of existing atherosclerotic disease. Patients with diabetes mellitus may be at higher risk for late coronary events than nondiabetic patients. In post–coronary artery bypass surgery (CABG) patients, the majority of late events relate to degeneration of saphenous vein grafts. Lipid lowering therapy after coronary revascularization has been shown to prevent clinical events related to plaque instability and inhibit progression of saphenous vein graft disease. Thus, there are 2 goals in management of patients with symptomatic coronary artery disease: (1) to relieve the flow-limiting stenosis, and (2) to prevent future clinical events with aggressive lipid lowering and modification of other risk factors. Patients, specialists, and primary care physicians each need to take accountability for this risk-factor modification.

Post-operative renal replacement therapy after coronary artery bypass surgery (CABG) in the UK, is the outlook still bleak?

Renal failure requiring acute haemofiltration occurs in 1–5% of patients after coronary artery bypass graft surgery (CABG). In-hospital mortality is reported between 28 and 63%.1 Few long term follow up studies have been published and outcome in patients with pre-operative dialysis dependent renal failure is unknown in the UK. Objectives of the study were to investigate early and late mortality following CABG surgery both in patients requiring acute haemofiltration and those already on chronic dialysis therapy. Forty-six patients who required acute and chronic renal replacement therapies post CABG between June 1996 and May 1999 were identified using the cardiac surgery data base and regional dialysis centre patient records. A control group of CABG patients without renal complications was also assessed. Thirty-day mortality, mortality at 1 yr and mortality rate ratios were examined. Functional quality of life in survivors was assessed using New York Heart Association (NYHA) and modified Karnofsky scores2 by telephone interview. Pre- and post-operative values were compared. The median follow up time was 469 days with a range of 1–1156 days. All statistical analyses were performed using STATA 6.0 for Windows 95. Post CABG surgery, acute renal failure requiring haemofiltration still carries a markedly increased risk of death despite better than previously reported in-hospital mortality (Table 20). Over 75% of survivors however report a functionally good quality of life with improved exercise tolerance and only 1 out of 30 renal failure patients describes himself as housebound. Chronic renal dialysis patients especially have very favourable outcomes, such that mortality rates are not statistically different from the control group.

Home exercise program for post-coronary artery bypass surgery(CABG) at King Chulalongkorn Memorial Hospital: Effectson exercise performance and quality of life

Home exercise program for post-coronary artery bypass surgery(CABG) at King Chulalongkorn Memorial Hospital: Effectson exercise performance and quality of life

Procainamide-induced postoperative pyrexia

Procainamide is an effective antiarrhythmic that is often used to convert atrial fibrillation to normal sinus rhythm. A side effect of procainamide, rarely reported in the surgical literature, is pyrexia. The pyrexia is a manifestation of an allergic response to this medication. If unrecognized, procainamide-induced pyrexia can lead to unnecessary testing, hospitalization, and treatment. We present a case of a post-coronary artery bypass surgery patient who repeatedly displayed pyrexia when reexposed to procainamide indicating an allergic response to this drug.

Mechanical Circulatory Support after Orthotopic Heart Transplantation

Frequently the only therapy for primary graft- and right heart failure, as well as low output syndrome from acute of chronic rejection, is implantation of a mechanical circulatory support system, until recompensation or retransplantation. At our institution, mechanical assist devices were implanted in 25 heart recipients for a cute rejection (n=9), primary graft failure (n=7), acute right heart failure (n=7), and chronic rejection with low output syndrome (n=2). Patients (pts) with primary graft failure (n=3) received an intraaortic balloon pump (IABP), one pt an IABP plus Abiomed-System for left ventricular support, one pt the Thoratec-System for biventricular support. Patients with right heart failure (RHF) received the Biomedicus centrifugal pump for right ventricular support. Nine pts suffered from acute rejection. Six pts received an IABP, one the Biomedicus as femoro-femoral bypass, one the Abiomed-System for biventricular support, two the Thoratec-System for biventricular support and two within this group switched from the Biomedicus pump to the Thoratec-System for biventricular support. Patients with chronic graft failure (n=2) received the Novacor-System (LVAD) for left ventricular support, one received a Tojobo-System and an oxygenator for biventricular support post coronary artery bypass surgery. Support time ranged from 0.5-h to 73 days. Five pts were weaned. Two (8%) of 25 pts were retransplanted, 18 (72%) died in spite of mechanical support from multiple organ failure. The use of a mechanical assist device after heart transplantation is encouraging only in the case of early right heart failure, as well as primary and chronic graft failure. In view of the poor results, the use of mechanical assist devices should not be recommended in the case of heart failure caused by acute rejection.

Determinants of Improvement in Exercise Capacity in Patients Undergoing Cardiac Rehabilitation

In order to identify patients who benefit most from a cardiac rehabilitation program, we studied retrospectively all patients who completed a 3-month comprehensive cardiac rehabilitation program during a 2-year period. Questionnaires regarding physical exercise habits were sent to 122 patients and returned by 117 (96%) of them (53 post-acute myocardial infarction, 50 post-coronary artery bypass surgery, 14 post-infarction and surgery, 2 post-angioplasty). Exercise capacity (subset of 66 patients) improved by 19% after rehabilitation (7.8 +/- 3.1 to 9.3 +/- 2.7 METs, p < 0.0001). Univariate and multivariate analysis identified initial exercise capacity as the only independent variable predicting improvement in exercise performance (inverse relationship) (r2 = 0.24, p < 0.0001). The improvement was not related to age, sex, left ventricular function or time from cardiac event to rehabilitation. Patients recovering from both infarction and coronary artery bypass surgery showed a greater improvement (delta exercise capacity 2.8 +/- 1.4 METs) than patients after myocardial infarction alone (delta exercise capacity 0.8 +/- 2 METs, p < 0.02). Improvement was sustained for up to 2 years after completion of the program.

The hemodynamic responses to upright exercise after orthotopic cardiac transplant.

The study was undertaken to examine the heart rate (HR) and stroke volume (SV) responses to upright exercise in patients after orthotopic cardiac transplantation (Group A). The findings were compared to data obtained from post-coronary artery bypass surgery patients (Group B) and from healthy subjects (Group C). All three groups (n = 12 in each group) were matched for age and gender. The preexercise HR and blood pressure were significantly higher in Group A (p < 0.05), whereas the SV was significantly lower (41 +/- 4mL.beat-1 vs 63 +/- 3 and 65 +/- 2 mL.beat-1 in Group B and C respectively, p < 0.05). In Group A, at submaximal work loads, the SV was consistently lower than in Groups B and C. During the early phases of exercise, the HR was consistently higher in Group A also. Systemic vascular resistance remained significantly higher in Group A throughout exercise (p < 0.05).

Coronary angioplasty in symptomatic patients after bypass surgery

With the availability of percutaneous transluminal coronary angioplasty (PTCA), the management of patients who present with recurrent angina following coronary artery bypass surgery (CABG) has changed. From January 1987 to December 1988, 149 symptomatic post CABG patients underwent coronary angiography at our institution. Ninety were treated with medical antianginal therapy, 14 had repeat surgery, and 45 underwent PTCA. Complications of repeat CABG included one death, two perioperative myocardial infarctions, and four patients with postoperative supraventricular arrhythmia. PTCA was performed on 42 lesions in 37 native vessels (88% success rate), and on 24 lesions in 24 vein grafts (91.7% success rate). Complications included acute reocclusion (one patient), peripheral artery occlusion (one patient), hematoma formation (one patient), and periprocedure myocardial infarction (one patient). No deaths occurred. At a mean follow-up of 5.9 ± 3.8 months, 10 patients had recurrent symptoms, six of whom were found to have restenosis. Repeat PTCA was successfully accomplished in four patients: the other two were treated medically. It is concluded that PTCA is a feasible alternative to repeat CABG in selected patients and can be achieved with a high success rate and minimal complications.

Indications, Criteria for Interpretation, and Utilization of Exercise Testing in Patients with Coronary Artery Disease

A questionnaire was distributed to approximately 50 U.S. Veterans Administration hospitals, closely associated with academic medical centers in 1988–89 to ascertain indications, criteria for interpretation, and utilization of standard exercise electrocardiography results. Forty-four completed questionnaires were returned providing data on 41,212 exercise tests performed in the previous year. One millimeter (mm) of horizontal or downsloping ST depression was still the predominant criteria for classifying an exercise test as abnormal (in 93 % of the laboratories). Class I indications for exercise testing including (1) diagnosing coronary artery disease (CAD) in male patients suspected of having CAD (32 %); (2) identifying the high-risk patient with known CAD (26 %); (3) post-myocardial infarction risk stratification and profiling (18%), and (4) testing the post-coronary artery bypass surgery patient with recurrent symptoms (12%) accounted for 88% of the reported use. Exercise Thallium-201 scintigraphy was used four times more often than exercise radionuclide ventriculography. Sixty-eight percent of patients discharged after a diagnosed acute myocardial infarction underwent exercise testing. Exercise electrocardiography continued to have a major impact for the evaluation and prognostication of patients with coronary artery disease, and its use at the surveyed centers was in agreement with AHA/ACC guidelines.