A number of risk factors have been associated with a higher incidence and a more rapid progression of coronary artery disease (CAD). Coronary artery bypass graft surgery (CABG) has been shown to provide symptomatic relief in over 80 percent of patients with angina refractory to medical therapy. The late postoperative course of patients after CABG is largely determined by the patients left ventricular function and by the graft patency rate. The influence of coronary risk factors on the late postoperative course is contradictory.
On the basis of our clinical observation that patients with hypercholesterolemia tended to have an unfavorable course after CABG, we studied the influence of preoperative risk factors, especially cholesterol levels, on the postoperative result in patients operated upon for chronic stable angina.
From 1974 to 1979, a total of 288 CABG operations were performed at this hospital. A total of 59 patients were excluded because of concomitant surgical procedures and 11 patients had prophylactic CABG in the absence of angina or CABG due to unstable angina. From the remaining 218 with isolated CABG performed for treatment of chronic stable angina, 186 patients formed the study group presented in this report; 24 patients had an insufficient data base (especially with regard to preoperative cholesterol levels), six patients died perioperatively (within 30 days), and two patients died within six months after operation.
There were 169 men and 17 women with a mean age (±SD) of 54 ±8 years (range 30 to 71 years). Clinical classification (NYttA) showed 73 percent of patients in classes 3 and 4 with regard to angina. Some 66 percent of the patients had suffered at least one myocardial infarction.
The CAD was confined to one vessel in 22 percent, two vessels in 36 percent, and three vessels in 42 percent of the patients. Left main disease was present in 11 percent of these patients. The run-off was judged for each of the three major coronary arteries from coronary angiograms in three different projections by a team comprised of a cardiologist, surgeon, and radiologist, and was considered unsatisfactory in at least one vessel in 46 of 186 (25 percent) patients. So many aspects should be taken into account in severe disorders treatment. Best drugs and low prices you may find in the Internet drug stores. More info for read on Canadian Health&Care Mall.
In 26 percent of the patients, the preoperative biplane ventriculogram revealed ejection fractions (EF) of less than 50 percent and in 63 percent of patients regional akinesia or dyskinesia of the left ventricle was observed.
Preoperative Rick Factors
At the time of catheterization, cholesterol levels were analyzed after a 12-hour fasting period. Initially, the method of Libermann-Burketson and since 1977, the method of Allain et al“ were used. Both methods had a day-to-day variation of 5 to 10 percent. Mean serum cholesterol levels were 7.01 ±1.39 mmol/L (± SD) with terciles of 3.2 to 6.5 (lower); 6.5 to 7.4 (mid); and 7.4 to 10.8 (upper). The mean value for serum triglycerides was 3.04 ±2.49 mmol/L. A history of hypertension (blood pressure >160/95) was present in 39 (21 percent) of the patients. Smoking histories revealed 65 (35 percent) nonsmokers, 52 (28 percent) exsmokers and 69 (37 percent) smokers of >ten cigarettes per day. Obesity of >20 percent overweight was observed in 85 (46 percent) of the patients. When hypertension, smoking, and hypercholesterolemia (>7.8 mmol/L) were considered as risk factors, 20 patients had no preoperative risk factors, 85 patients had one risk factor, 72 patients had two, and nine patients had three concomitant risk factors.
A total of 374 saphenous-vein-coronary artery bypass grafts were inserted in these 186 patients (mean 2.01 bypass per patient); 32 percent of the patients received one, 41 percent two, 22 percent three, and 5 percent received four CABG. The revascularization was incomplete (ungrafted vessels with over 50 percent stenoses) in 53 (28 percent) patients. The operation was performed during cardiopulmonary bypass using potassium cold cardioplegia for myocardial protection.
Patients were followed at a special clinic by cardiologists three months pos tope rati vely, and yearly thereafter, provided they had an uncomplicated course. Angina was again classified according to the NYHA criteria. For long-term evaluation, the follow-up was considered favorable when angina was absent or improved by at least two NYHA classes during the entire follow-up period. The mean follow-up was 54 (range 6 to 113) months, 50 percent of the patients were followed for at least five years. Due to the decreasing number of patients, figures representing life table results show a follow-up over seven years only.
The CABG-patency was assessed two weeks postoperatively in virtually all patients since 1977. Early postoperative angiograms were therefore available in 59 percent of all patients.
Follow-up data were analyzed by an actuarial life-table method for survival and reappearance of angina pectoris (Cutler-Ederer, BMDP program P1L). Actuarial curves were compared using the statistical test by Lee and Desu (SPSS implement). In a subgroup fo 93 patients with a follow-up of at least five years, the influence of risk factors on the postoperative course was analyzed by a stepwise logistic regression (SAS, logistic procedure).