Asian Cardiovasc Thorac Ann 2002;10:211-214
© 2002 Asia Publishing EXchange Pte Ltd
Coronary Artery Bypass in Patients With Severe Left Ventricular Dysfunction
Dronamraju Dilip, FRCS,
Mangu H Rao, MD,
Abha Chandra, MCh,
M Sanjeeva Rao, MCh,
Durgaprasad Rajasekhar, DM1,
Sribhasyam Venkateswara Prasad, MD,
Alladi Mohan, MD
Department of Cardiovascular and Thoracic Surgery
1 Department of Cardiology Sri Venkateswara Institute of Medical Sciences Tirupati, Andhra Pradesh, India
|
|
|
For reprint information contact: Dronamraju Dilip, FRCS Tel: 91 8574 87777 Fax: 91 8574 86803 email: drdilip_d{at}yahoo.com Department of Cardiovascular and Thoracic Surgery, Sri Venkateswara Institute of Medical Sciences, Tirupati, Andhra Pradesh 517507, India.
|
 |
ABSTRACT
|
|---|
We retrospectively reviewed the case records of 82 patients with severe left ventricular dysfunction (ejection fraction < 30%) who underwent coronary artery bypass grafting between March 1993 and February 2000. They were aged 28 to 76 years (mean, 60 years), and 66 of them were male. Significant comorbid factors included hypertension (93%), diabetes mellitus (85%), and hypercholesterolemia (49%). The number of grafts used ranged from 1 to 3. The majority of the patients (91%) belonged to the Canadian Cardiovascular Society angina class III. Coronary angiography revealed single-vessel (in 16% of the patients), double-vessel (52%), and triple-vessel disease (32%), and left main stem disease (18%). Seven patients (9%) died within 48 hours after surgery. The mean duration of hospital stay was 7 ± 2 days. The 75 patients who survived were followed up for 3 months to 7 years. At the 1-year follow-up, 61 of the 68 patients (90%) who were alive moved up from angina class III to class I. Our observations suggest that coronary bypass carries an acceptable mortality risk and may offer a better quality of life in patients with poor ventricular function.
|
INTRODUCTION
|
|---|
Few cardiac surgery centers worldwide undertake coronary artery bypass grafting (CABG) in high-risk patients with severe left ventricular (LV) dysfunction, preferring to maintain them on medical management.1–5 However, medical management of these cases requires repeated hospital admissions and lowers the quality of life. In addition, many places around the world do not have facilities for heart transplantation. Besides, postoperative management of transplant patients is costly and donors may be scarce, especially in developing countries. We critically reviewed our experience with CABG as a therapeutic option in patients with severe LV dysfunction to evaluate the risk and to devise future strategies to improve the outcome.
|
PATIENTS AND METHODS
|
|---|
We retrospectively reviewed the case records of 82 patients with an LV ejection fraction (EF) below 30% who underwent CABG between March 1993 and February 2000 at our institute, a tertiary care center catering to a population of 3 million. These patients required repeated hospital admissions and had a lower quality of life before the surgery. Surgery was offered to patients with severe LV dysfunction whose coronary arteries measured more than 1.25 mm in diameter by angiography.
General endotracheal anesthesia was induced with midazolam, fentanyl, and propofol. Ventilation was controlled with oxygen and anesthesia maintained with inhalational isoflurane, propofol, and fentanyl. All operations were performed under cardiopulmonary bypass without cooling. Topical ice slush was used in the pericardium. After heparinization, extracorporeal circulation was instituted with a Sarns 9000 heart lung machine (3M Health Care, Ann Arbor, MI, USA) using a membrane oxygenator in 64 of the 82 patients (78%) and a bubble oxygenator in the remaining 18 (22%) irrespective of the number of grafts.
A Sarns aortic cannula and two-stage venous cannulae were used to institute coronary bypass. Cardioplegia was administered using a rapid infusion set after aortic crossclamping. Blood cardioplegia was used in 46 patients (56%) and cold crystalloid cardioplegia in 28 (34%); the remaining 8 patients (10%) underwent grafting with partial support and a beating heart. In view of the low EF and the presence of comorbid factors, we used the reversed saphenous vein as the conduit. All the patients were weaned off cardiopulmonary bypass with inotropic support of dobutamine and adrenaline. No patients required intraaortic balloon pumping.
|
RESULTS
|
|---|
The mean age of the patients was 60 years (range, 28 to 76 years). There were 66 males, of whom 30 were smokers. None of the 16 females were smokers. All of the patients were managed medically by cardiologists for a mean period of 5.3 ± 2.4 days (range, 3 to 14 days) before being referred for consideration for surgery. Their comorbid factors and clinical characteristics are shown in Table 1
. Hypertension (93%) and non-insulin-dependent diabetes mellitus (85%) were common associated conditions. Seventeen patients (21%) had a history of myocardial infarction, 6 of whom (35%) were operated on within 3 weeks of the episode.
View this table:
[in this window]
[in a new window]
|
Table 1. Comorbid Factors and Clinical Characteristics of 82 Patients With Severe Left Ventricular Dysfunction Who Underwent Coronary Artery Bypass Grafting
|
|
The operative characteristics of the patients are shown in Table 2. Endarterectomy was performed in 56% of the patients. Following surgery, the patients remained on inotropic support for a minimum of 3 to 4 days. Perioperative complications are listed in Table 3. Two patients developed perioperative myocardial ischemia, reflected in electrocardiographic changes. Seven patients developed sternal dehiscence as a result of nonhealing of the wound, and 5 of these patients were diabetic. Ten patients developed pulmonary complications, 4 of whom required tracheostomy.
There were no operative deaths. Seven patients (9%) died within 48 hours after surgery because of low cardiac output, uncontrollable ventricular dysrhythmias, and perioperative myocardial infarction.
The surviving 75 patients were followed up for 3 months to 7 years. At the 1-year follow-up, 7 of them (9%) had died from cerebrovascular accident and cardiac events. Of the surviving 68 patients, 61 (90%) moved up from angina class III to class I of the Canadian Cardiovascular Society classification. In the subsequent 2 years, 10 more patients were lost to follow-up. None of the remaining patients who were followed up died. Of these 58 patients, 34 (59%) regularly required antianginal drugs.
|
DISCUSSION
|
|---|
In the backward Rayalaseema area where our center is located, the majority of patients seek surgery very late in their disease because of the inability to afford surgery. Often, comorbid factors also are identified at a late stage. These patients are often malnourished. For these reasons, they are usually refused operation at other centers. Diabetes mellitus and related small-vessel disease are a growing public health problem in India. Patients often go undiagnosed because they do not have access to healthcare and biochemical testing. Given this background, and the observation that diabetes mellitus is an established independent risk factor for significant morbidity and mortality after CABG,1 a high proportion of the patients develop complications such as sternal dehiscence. However, surgery seems to be advantageous in these patients as it reduces the expenditure on medications and the number of hospital visits.
In a study reported by Christakis and colleagues,6 patients with a preoperative EF > 40% (n = 9,445) had a lower operative mortality rate (2.3%) than patients (n = 2,539) with an EF of 20% to 40% (4.8%) and those (n = 487) with an EF < 20% (9.8%). However, those with an EF < 20% were found to be demographically distinct from those with higher EF. This group was older, with fewer women, a higher frequency of left main stem stenosis, and a higher incidence of urgent operation for unstable angina. The only predictor of the risk of operative death for this group was the urgency of operation.
Milano and associates7 studied 118 consecutive patients with an EF at or below 25% who underwent isolated CABG. Operative mortality was 11%. Ventricular arrhythmia requiring treatment was the most common postoperative complication (27%), followed by low cardiac output (22%). The median length of postoperative hospitalization was 9 days. Estimates of survival at 1 and 5 years were 77.2% and 57.5%, respectively, which were better than estimated survival with medical therapy alone. The presence of other vascular diseases, the female sex, hypertension, an elevated LV end-diastolic pressure, and a depressed cardiac index were found to be factors associated with higher mortality. They concluded that patients with severely depressed LV function would benefit from CABG.
In a study reported by Kaul’s group,5 5.8% of patients (n = 210) who underwent CABG had severely impaired global LV function with an EF < 20%. Overall, actuarial survival of these patients was 82%, 79%, and 73% at 1, 2, and 5 years, respectively. The risk of death was highest in the immediate period after operation and then declined rapidly to a constant level. Patients who did not receive retrograde coronary sinus cardioplegia, older patients, and those with preoperative ventricular arrhythmias or renal failure had an increased risk of early death after operation. When the number of distal anastomoses performed increased, survival was found to decrease, especially in women.
The mortality rate in the present series was 9%, similar to those reported by Milano’s group7 (11% in patients with an EF < 25%) and Christakis’s group6 (9.8% in patients with an EF < 20%). Our findings concur with those of other studies that patients suffering from coronary artery disease with severe LV dysfunction can undergo myocardial revascularization with acceptable results.6–10 This observation has relevance especially in the setting of the developing world.
As in other studies,9,11,12 we performed all the distal anastomoses in a single crossclamping session using cold crystalloid or blood cardioplegia. During surgery, endarterectomy is usually performed in the right coronary artery in many centers worldwide.13 We followed the same strategy, and 33% of our patients underwent endarterectomy in the right coronary artery. Where lesions involve the left anterior descending and circumflex vessels, endarterectomy is generally not performed. Contrary to the usual practice, we had to perform it more frequently in these vessels as they were less than 1.25 mm in size with diffuse multiple limiting stenosis or heavy calcification.
Our observations suggest that CABG carries an acceptable mortality risk and may offer a better quality of life in patients with poor ventricular function. These results seem to hold good not only in the industrialized world, but even in developing countries like India.
|
REFERENCES
|
|---|
- Thourani VH, Weintraub WS, Stein B, Gebhart SSP, Craver JM, Jones EL, et al. Influence of diabetes mellitus on early and late outcome after coronary artery bypass grafting. Ann Thorac Surg
1999;67:1045–52.[Abstract/Free Full Text]
- Yau TM, Fedak PWM, Weisel RD, Teng C, Ivanov J. Predictors of operative risk for coronary bypass operations in patients with left ventricular dysfunction. J Thorac Cardiovasc Surg
1999;118:1006–13.[Abstract/Free Full Text]
- Trachiotis GD, Weintraub WS, Johnston TS, Jones EL, Guyton RA, Craver JM. Coronary artery bypass grafting in patients with advanced left ventricular dysfunction. Ann Thorac Surg
1998;66:1632–9.[Abstract/Free Full Text]
- Baumgartner FJ, Omari BO, Goldberg S, Pandya AB, Pandya AB, Daland AM, et al. Coronary artery bypass grafting in patients with profound ventricular dysfunction. Tex Heart Inst J
1998;25:125–9.[Medline]
- Kaul TK, Agnihotri AK, Fields BL, Riggins LS, Wyatt DA, Jones CR. Coronary artery bypass grafting in patients with an ejection fraction of twenty percent or less. J Thorac Cardiovasc Surg
1996;111:1001–12.[Abstract/Free Full Text]
- Christakis GT, Weisel RD, Fremes SE, Ivanov J, David TE, Goldman BS, et al. Coronary artery bypass grafting in patients with poor ventricular function. Cardiovascular Surgeons of the University of Toronto. J Thorac Cardiovasc Surg
1992;103:1083–91.[Abstract]
- Milano CA, White WD, Smith LR, Jones RH, Lowe JE, Smith PK, et al. Coronary artery bypass in patients with severely depressed ventricular function. Ann Thorac Surg
1993;56:487–93.[Abstract]
- Hochberg MS, Parsonnet V, Gielchinsky I, Hussain SM. Coronary artery bypass grafting in patients with ejection fractions below forty percent. Early and late results in 466 patients. J Thorac Cardiovasc Surg
1983;86:519–27.[Abstract]
- Yamaguchi A, Mizuhara A, Ide H, Ino T, Ohwa M, Saito M, et al. Coronary artery bypass grafting in two patients with severe left ventricular dysfunction [Japanese]. Kyobu Geka
1991;44:919–23.[Medline]
- Hirooka Y, Tahara M, Sasaguri S, Kikuchi N, Satou T, Watanabe T, et al. The effects of coronary revascularization in patients with severe left ventricular dysfunction [Japanese]. Nippon Kyobu Geka Gakkai Zasshi
1991;39: 1024–31.[Medline]
- Antunes MJ, Bernardo JE, Oliveira JM, Fernandes LE, Andrade CM. Coronary artery bypass surgery with intermittent aortic cross-clamping. Eur J Cardio-thorac Surg
1992;6:189–93.[Abstract]
- Bonchek LI, Burlingame MW, Vazales BE, Lundy EF, Gassmann CJ. Applicability of noncardioplegic coronary bypass to high-risk patients. Selection of patients, technique, and clinical experience in 3000 patients. J Thorac Cardiovasc Surg
1992;103:230–7.[Abstract]
- Livesay JJ, Cooley DA, Hallman GL, Reul GJ, Ott DA, Duncan JM, et al. Early and late results of coronary endarterectomy. Analysis of 3,369 patients. J Thorac Cardiovasc Surg
1986;92:649–60.[Abstract]
TOP
ABSTRACT
INTRODUCTION
