Coronary artery surgery as we know it today, has undergone rapid evolution since its introduction in the late 1960's, resulting, not surprisingly, in much confusion. In an attempt to present the state of the art, a collective review of the literature, coupled with the experiences with 118 patients is presented and discussed. The modern surgical management of patients with obliterative coronary artery disease is designed to relieve symptoms, prolong life and identify patients at high risk of premature death or myocardial infarction if they were to continue with medical management. Though the most common indication for surgery is persistent limitation of life style by severe symptoms, management is influenced by the strong association between such symptoms and increased mortality. During the short history of coronary bypass surgery, other indications for operation have been influenced by a combination of lessons from the past and hopes for the future. In addition, advances in technology have produced an enormous impetus for improvements in patient evaluation, surgical technique and postoperative care. As these advances continue and as more and more late results of surgery become available, answers to questions about surgery may increasingly be deduced from lessons rather than from hopes. As a result of these changes, an aura of confusion has gradually crept into the scene. It is hoped that this collective review, together with experiences gained from a personal series of 118 patients over a 3 year period from 1984 to 1986, will put into proper perspective, the state of the art of surgical management of coronary artery disease today.
A personal series of 163 patients who underwent coronary artery bypass surgery (CABG) in the University Hospital, Kuala Lumpur between March 1988 and December 1990 were reviewed retrospectively to determine factors affecting hospital morbidity and mortality. One hundred and thirty eight were elective cases while 25 patients underwent emergency CABG surgery. Of these, 15 patients had recent myocardial infarction, with unstable haemodynamics or post infarct angina; six had failed angioplasty procedures and four patients immediately following coronary angiogram. The elective hospital mortality rate was 2.2% (three cases) and there were two deaths in the emergency group. Pre-operatively 20 patients (13%) had very poor left ventricular function of less than 30% ejection fraction. Significant improvement in ejection fraction was observed following surgery. The follow-up periods were between three months to three years. Ninety eight percent of patients showed improvement in their functional status (NYHA classification) in relation to angina and exercise performance.
The authors report 4 Oriental cases of total occlusion of the left main coronary artery (LMCA) with differing presentations. The first patient had a twelve-year history of stable angina pectoris. The second patient had angina for a year, which became unstable two months prior to diagnosis. The third patient had myocardial infarction seven years ago and presented with a one-month history of rest angina. The fourth patient had stable effort angina for six years but presented with accelerated angina three months prior to diagnosis. The incidence of total occlusion of the LMCA is rare and survival depends on the existence of collateral circulation. In LMCA disease, there is usually disease in other parts of the coronary arterial tree, and hence, the need for urgent coronary bypass surgery.
The pharmacokinetics of propofol was studied in 11 Asian patients with fentanyl-isoflurane anaesthesia during cardiopulmonary bypass (CPB) and undergoing elective coronary artery bypass grafting (CABG). Instead of the usual increments of morphine and a benzodiazepine, propofol (4 mg/kg/h) was initiated at the start of CPB and ceased at CPB separation. Whole blood propofol concentrations were determined during and postinfusion using high-performance liquid chromatography with fluorescence detection. Data from four patients seemed to fit a two-compartment model, whereas those from seven patients were significantly (F test, p < 0.05) better fitted to a three-compartment model. The pharmacokinetic parameters were as follows: The mean (SD) of the initial distribution phase t1/2 pi, intermediate distribution phase t1/2 alpha, and elimination phase t1/2 beta were 2.22 (1.04) min, 42.9 (16.4) min, and 370 (138) min, respectively. The mean clearance of 1.31 (0.50) L/min was lower than those reported from other studies, whereas the mean blood concentration of 2.2 (1.0) mg/L at the 1-h infusion period was higher. The mean calculated apparent Css was 3.9 (1.5) mg/L. The low clearance is likely to be due to hemodynamic changes during CPB and CABG, thereby affecting drug distribution and blood flow to the liver.
Oxygen consumption values calculated by Fick's principle (cVO2) were compared to simultaneously obtained values measured by indirect calorimetry (mVO2) in two groups of patients; post-coronary artery bypass graft (post-CABG) and septic shock. In both groups of patients, oxygen consumption values derived using indirect calorimetry were higher than that from Fick's principle. Whilst the bias obtained between the two methods of measurement were of acceptable amount clinically, the limits of agreement were wide: -57 to 51 ml.min-1.m-2 in the post-CABG group and -101 to 67 ml.min-1.m-2 in the group of septic patients; indicating that significant differences exist between paired individual values such that cVO2 and mVO2 were not interchangeable in this study.
Fasting serum specimens from (a) 217 male and 46 female patients with coronary artery disease (CAD), aged 35-75 years, who had undergone angioplasty (PTCA) / coronary artery bypass graft (CABG), and (b) 160 apparently healthy controls (106 males, 54 females, aged 30-75 years), were assessed for serum lipid profile. Both sex and ethnicity significantly influenced the levels of serum high density lipoprotein cholesterol (HDLC); in the controls, females had higher HDLC levels than males (46.7 mg/dl vs 38.5 mg/dl, p
A 52 year old hypertensive Malay man, a smoker who presented with a one month history of mild chest discomfort not related to exertion and had a positive stress test with ST segment depression in the lateral leads. Coronary angiography showed stenosis in the right coronary artery and a coronary aneurysm in the proximal segment of his left anterior descending. The aneurysm was situated just distal to a stenotic lesion. The aneurysm is most likely related to atherosclerotic coronary artery disease. The patient was treated with oral nitrates, aspirin, angiotensin converting enzyme inhibitor and warfarin to prevent thromboembolism related to the coronary aneurysm. He remains asymptomatic one year after diagnosis.
Comment on: Yeo CK, Khalid Y. Solitary focal coronary artery aneurysm in a middle aged
male with atypical chest pain. Med J Malaysia. 1999 Mar;54(1):114-6
We tested the hypothesis that NO contamination of hospital compressed air also improves PaO(2) in patients with acute lung injury (ALI) and following lung transplant (LTx).
A retrospective study was done on 302 patients who had undergone coronary artery bypass grafting (CABG) in Hospital Universiti Kebangsaan Malaysia--46.0% were Chinese, 40.1% were Malays and 11.6% were Indians. Overall and irrespective of race and sex, the prevalence of diabetes mellitus, hypertension and hyperlipidaemia was 45.7%, 78.8% and 89.1% respectively indicating that hyperlipidaemia was the most prevalent risk factor amongst this cohort. The Indians had the highest prevalence of the three risk factors. The Chinese and the Malays most frequently presented with the combination of hypertension and hyperlipidaemia.
We present a case report of a 60-year-old Malay man who was undergoing an urgent coronary artery bypass graft (CABG) operation when a well encapsulated thymoma-like tumor was found incidentally. Total thymectomy was performed together with the CABG. Histopathological report of the tumor, however, confirmed a rare thymic carcinoid. The clinical features, management, and outcome of surgery are discussed.
Our purpose is to report on the epidemiological variables and their association with the results of the exercise tolerance test (ETT) in the series of patients referred for standard diagnostic ETT at Seremban Hospital during the year 2001. ETT is widely performed, but, in Malaysia, an analysis of the associations between the epidemiological data and the results of the ETT has not been presented. All patients referred for ETT at Seremban Hospital who underwent exercise treadmill tests for the year 2001 were taken as the study population. Demographic details and patients with established heart disease (i.e. prior coronary bypass surgery, myocardial infarction, or congestive heart failure) were noted. Clinical and ETT variables were collected retrospectively from the hospital records. Testing and data management were performed in a standardized fashion with a computer-assisted protocol. This study showed that there was no significant predictive epidemiological variable on the results of the ETT. However, it was found that there was statistically significant difference between the peak exercise time of males and females undergoing the ETT.
We present an interesting but high-risk case of an obese male patient aged 56 years with dextrocardia and a left diaphragmatic hernia. Anterior myocardial infarction was diagnosed in 1994, and the patient later presented with a history of unstable angina. The diagnosis for this chronic smoker was triple-vessel disease, impaired left ventricular function, chronic renal failure, chronic bronchitis, impaired lung function, pulmonary hypertension, hypertension, diabetes, and chronic active gastritis (EuroSCORE of 10). The patient underwent successful off-pump coronary artery bypass grafting with 3 saphenous vein grafts to the left anterior descending, obtuse marginal, and right posterior descending arteries. He was discharged home 8 days later.
From April 2002 to March 2005, 18 patients having undergone bidirectional Glenn shunt (BDG) without cardiopulmonary bypass (CPB) [off-pump BDG] were retrospectively reviewed. During BDG anastomosis, a temporary bypass was established between superior vena cava (15) or innominate vein (3) and main pulmonary artery (16) or right atrium (2). Hemodynamics and oxygenation were maintained well throughout the temporary bypass time. There was no emergent use of CPB. Mean transpulmonary pressure gradient immediately after and 24 hours after the BDG were 6.7 and 5.6 mmHg, respectively. Echocardiography showed mild flow turbulence at the anastomosis in 1 case. This simple and inexpensive technique provided good surgical view with stable hemodynamics enabling satisfactory BDG in selected cases. Furthermore, it could avoid adverse effects of CPB such as lung injury and possible blood transfusion. This experience would encourage off-pump BDG combined with more challenging procedures.
The authors describe the case of a 50-year-old man with chronic progressive external ophthalmoplegia (CPEO), diabetes mellitus (DM), and coronary artery disease. The patient had no cardiac conduction abnormalities. During coronary artery bypass surgery, his heart and two skeletal muscles were biopsied. All three muscles showed ragged red fibers. The heart muscle showed significant glycogen accumulation. Analysis of mitochondrial DNA (mtDNA) showed a 5019-base-pair deletion, with no duplications. There were morphologically abnormal mitochondria in all 3 muscles, with clinically apparent difference in preservation of function. The combination of diabetes mellitus and mtDNA deletion is fortuitous, as they can be causally linked. The cardiac pathology allows speculation about the possible adaptive processes that may occur in the heart in DM. There are few reported cases with CPEO and excess glycogen in the heart. Most show deposition of fat and poorer clinical outcomes as compared to those with glycogen deposition. This observation may lend support to the hypothesis that in the myocardium, adaptive responses are mediated via changes in glucose handling, whereas alterations in fat metabolism likely represent maladaptation.
A 58 year-old man presented with a large aneurysm of the aortic arch and severe coronary artery disease. He underwent combined repair of the aortic arch aneurysm and coronary artery bypass grafting via a modified clamshell incision using deep hypothermic circulatory arrest and retrograde cerebral perfusion. He made an uncomplicated postoperative recovery. The operative techniques are discussed with a review of the relevant literature.
A prospective study was carried out to compare the outcomes of patients with preexisting non-dialysis-dependent renal dysfunction who underwent coronary artery bypass grafting with or without cardiopulmonary bypass. Elective off-pump coronary artery bypass was performed in 29 patients with renal dysfunction. Their results were compared with those of a similar group of 35 patients who underwent the conventional on-pump coronary artery grafting. There was a significant deterioration in creatinine clearance in the on-pump group on days 1, 2, and 4 after surgery, while creatinine clearance in the off-pump group remained close to the baseline level. Both groups had improved to the preoperative creatinine clearance values on follow-up at 4 weeks. It was concluded that off-pump surgery provided better renal protection than the conventional on-pump technique in patients with preexisting non-dialysis-dependent renal dysfunction.
The aim of this study was to compare 6% hydroxyethyl starch 130/0.4 with 4% succinylated gelatin for priming the cardiopulmonary bypass circuit and as volume replacement in patients undergoing coronary artery bypass, in terms of postoperative bleeding, blood transfusion requirements, renal function, and outcome after surgery. Forty-five patients received 6% hydroxyethyl starch 130/0.4 (Voluven) and another 45 were given 4% succinylated gelatin (Gelofusine) as the priming solution for the cardiopulmonary bypass circuit as well as for volume replacement. Postoperative bleeding was quantified from the hourly chest drainage in the first 4 h and at 24 h postoperatively. The baseline characteristics of both groups were similar. In the hydroxyethyl starch group, the total amount of colloid used was 1.9 +/- 1.0 L, while the gelatin group had 2.0 +/- 0.7 L. There was no significant difference in hourly chest drainage between groups. Blood transfusion requirements, estimated glomerular filtration rate, extubation time, intensive care unit and hospital stay were similar in both groups. It was concluded that 6% hydroxyethyl starch 130/0.4 is a safe alternative colloid for priming the cardiopulmonary bypass circuit and volume replacement in patients undergoing coronary artery bypass surgery.
Sternal dehiscence is a rare but devastating complication following median sternotomy for cardiac surgery. The optimal technique for sternal closure is unclear. We conducted this prospective randomized trial to compare the incidence of sternal dehiscence after figure-of-8 and simple interrupted suturing in patients undergoing coronary artery bypass grafting. Between January 2007 and June 2008, 98 patients had figure-of-8 suturing and 97 had interrupted sutures. The mean age of the patients was 60.9 +/- 7.6 years. The overall sternal dehiscence rate was 8%; 7 cases in the in figure-of-8 group and 9 in the interrupted group. Thirteen patients had no wound infection and healed with conservative treatment. Only 3 patients had sternal dehiscence with infection: 2 with simple interrupted closure and 1 with figure-of-8 sternal closure. There was no significant difference in rates of sternal dehiscence between the 2 groups. It was concluded that figure-of-8 sternal suturing is equally effective as simple interrupted suturing in preventing sternal dehiscence.
Delayed ascending aortic dissection following coronary artery bypass surgery is a rare but lethal complication. We present the case of a 54-year-old man with a delayed acute Stanford A aortic dissection following an off-pump coronary artery bypass surgery in preexisting chronic type B disease. Such a case of an iatrogenic acute aortic dissection poses a significant challenge and dilemma in choosing the best technique for coronary revascularization in this group of patients. The pathophysiology and technical options are discussed.