Improved patency of the aortocoronary bypass by antithrombotic drugs

A total of 1,017 bypasses were performed in 442 patients operated on in our department between January 1, 1981, and May 30, 1984. The overall early postoperative graft patency rate in our hospital was 91.5%. About 10% of the grafts had a flow rate of 40 ml/min or less, measured intraoperatively, and most occluded grafts were in this group. This article presents our experience with low-flow bypasses whose patency rates we attempted to improve. Patients with aortocoronary bypasses (ACBs) and with intraoperative blood flow rates of 40 ml/min or less were divided into two groups. The treated group was given, from day 0 onward, a 500-mg dose of acetylsalicylic acid twice a day and a 75-mg dose of dipyridamole three times a day. The control group was given no medication. Control coronary arteriography was performed at one month and then at one year after the operation. One month postoperatively, 34 out of 41 ACBs in the treated group were patent; in the control group, only 17 out of 37 were patent (p less than .001). One year after the operation, 24 out of 37 ACBs in the treated group were patent, whereas in the control group only 8 out of 38 ACBs were patent (p less than .001). We conclude that antiplatelet drugs have a beneficial effect on the short-term and long-term patency of ACBs.     

Amelioration of the bleeding tendency of preoperative aspirin after aortocoronary bypass grafting

BACKGROUND: Aspirin therapy is widely used in the treatment of cardiac disease. It has been recognized as a causative factor for increased bleeding and blood loss after open heart operations. METHODS: To determine whether high-dose aprotinin maintained its efficacy in reducing blood loss in the presence of aspirin pretreatment in patients undergoing aortocoronary bypass, we performed a double blind study on 60 adult patients. Half received high-dose aprotinin (Trasylol) and half placebo. RESULTS: Total hemoglobin loss, the primary efficacy variable was reduced from 36.1 +/- 31.4 g (mean +/- SD) to 14.1 +/- 16.0 g (p = 0.002). Blood loss was reduced intraoperatively and total loss was reduced from 837.3 mL +/- 404.9 mL to 368.7 mL +/- 164.3 mL (p < 0.001). The number of patients who did not receive any donor blood products was significantly higher in the aprotinin-treated patients (56.7% versus 23.3%, p = 0.008). Activation of the clotting cascade was significantly less in the treated patients toward the end of cardiopulmonary bypass both by measurement of thrombin-antithrombin III complex (p < 0.0001) and prothrombin fragment 1 + 2 (p < 0.0001). D-Dimer generation was significantly less from the onset of bypass and after reversal of heparin in the aprotinin-treated patients (p < 0.0001). CONCLUSIONS: High-dose aprotinin was highly effective in reducing bleeding in this high-risk group of patients. Biochemical analyses suggest the mechanism by which aspirin increases blood loss after cardiopulmonary bypass is different from the blood-preserving effects of aprotinin, which is acting as an antifibrinolytic agent.     

Effect of dipyridamole (Persantin) on blood flow and patency of aortocoronary vein bypass grafts

The effect of dipyridamole was investigated in 360 patients undergoing coronary bypass surgery. They were randomly allocated to receive dipyridamole (100 mg orally q.i.d. for 2 days preoperatively, 5 mg/kg body weight/24 h i.v. peroperatively and 100 mg orally q.i.d. for 1 year postoperatively) or placebo. Withdrawn from the study were 48 patients on dipyridamole and 57 on placebo. Cardiovascular and/or cerebrovascular events or need for anticoagulant treatment were the reasons for withdrawal in 22 (13%) of the dipyridamole, and 34 (18%) of the placebo group. Logistic regression analysis of risk factors influencing graft patency showed significant relation to peroperatively measured coronary blood flow. A positive trend of treatment was observed (p = 0.08). Vein graft blood flow measured during bypass surgery (245 patients) was significantly greater in the dipyridamole group (p less than 0.01). The occlusion rate was lower in vessels with peroperative blood flow greater than 30 ml/min (vein-marginal p less than 0.01, vein-dexter p less than 0.05, vein-diagonal 0.05 less than p less than 0.1). Dipyridamole increases coronary blood flow and graft patency following coronary bypass surgery.     

Estimation of intraoperative aortocoronary bypass saphenous vein graft circumference from its preoperative compliance

The aim of this study was to determine if the intraoperative circumference of aortocoronary saphenous vein bypass grafts could be predicted from preoperative measurement with B-mode ultrasound sonography in 50 patients. The circumference of the saphenous vein was measured during stepwise increments of a thigh congestive cuff from 0 to 60 mmHg. The circumference of the corresponding segment of the coronary bypass vein graft was measured intraoperatively with callipers. The intraoperative circumference was higher (11.8+/-2.3 mm) than the preoperative circumference (10.2+/-2.4 mm, P=0.006) matched to its corresponding intraoperative mean arterial pressure (57+/-15 mmHg). The prediction of the intraoperative circumference by estimation from the preoperative pressure-circumference relationship fitted by a linear model (r = 0.412, P = 0.004) did not improve on the preoperative circumference matched by arterial pressure alone (r = 0.429, P = 0.003). The intraoperative circumference of the graft vein exceeded its preoperative circumference by 12%. Prediction of the intraoperative graft vein circumference is underestimated by a linear model of its preoperative compliance.     

Mediastinal wound infection and aortocoronary graft patency.

In our experience, eight of ten aortocoronary grafts in five patients remained patent in the face of mediastinal infection. Combining reports of seventeen other grafts from the literature, we conclude that patency can be anticipated in approximately 70 per cent of such grafts and that mediastinal infection does not necessarily adversely affect aortocoronary saphenous vein bypass graft patency. We recommend aggressive therapy of mediastinal infection in this setting due to the high survival rate which can be anticipated with modern methods of therapy, as well as the high probability of graft patency.     

Critical analysis of jejunoileal bypass

This study analyzed a group of morbidly obese patients who underwent jejunoileal bypass over a 10 year period. Patients underwent either a Payne or Scott procedure. Weight loss was reported in terms of percent of excessive weight loss. Results showed that patients who had a Payne bypass had an average excess weight loss of 75 percent, whereas those with the Scott bypass had an average excess weight loss of 61 percent. All patients lost weight. Complications in this series were lower than what has been traditionally reported. The problem that occurred most often was kidney stones (8 percent of the patients). There has been only one death to date. The low incidence of complications can be attributed to the fact that the patients were evaluated, operated on, supervised, and followed by one doctor and his associated nurses. Thus, it is proposed that jejunoileal bypass, compounded with good patient care and careful patient selection, can produce positive results with a minimum number of problems.     

Diagnosis of aortocoronary bypass complications

Thirty-four patients with ischemic heart disease were examined during operation for revascularization of the myocardium. The blood flow in the shunts was measured during the change from extracorporeal to natural circulation. In rise of venous and arterial pressure the blood flow in the shunts increased (positive dynamics) in some patients and decreased (negative dynamics) in others. Positive dynamics were associated with a favourable course of the postoperative period, negative dynamics--with ischemic-type complications. Factors invalidating the myocardium aggravated the initial condition of patients with positive dynamics of the blood flow less than that of patients with negative dynamics. Comparison of dynamic and short-term measurement of the blood flow in the shunts as a diagnostic test for perioperative complications showed the advantage of the dynamic test.     

Preoperative angiographic score and intraoperative flow as predictors of the mid-term patency of infrapopliteal bypass grafts.

OBJECTIVES: preoperative angiographic characteristics of the outflow tract have emerged as a predictive factor for the outcome of infrapopliteal reconstructions. Direct flow measurement can be routinely performed intraoperatively, but little is known regarding its impact on graft outcome. The present study was undertaken to compare the value of these parameters in predicting the mid-term patency of infrapopliteal bypass grafts. DESIGN: retrospective clinical study. PATIENTS: 172 infrapopliteal reconstructions using autogenous vein were performed, of which 92 had a crural and 80 a pedal recipient artery. METHODS: the preoperative angiogram was scored according to the SVS/ISCVS Ad Hoc Committee. At the end of the operation flow was measured with a transit-time flowmeter. Follow-up consisted of pressure measurements and duplex scanning. RESULTS: the runoff score had no impact on femorocrural graft patency. For pedal grafts there was a tendency for inferior outcome with high runoff score, as the 1-year assisted primary patency for grafts with a completely occluded pedal arch was 11% compared with 52% for grafts with lower scores (p=0.056). Both intraoperative volume graft flow and maximum flow capacity had a highly significant influence on the outcome on crural reconstructions on univariate analysis. For pedal reconstructions only a a severely reduced maximum flow capacity after injection of papaverin was associated with an adverse outcome. Multivariate analysis revealed that maximum flow capacity was an independent significant factor affecting patency of femoroinfrapopliteal grafts (relative risk=0.53 per 30 ml/min increase, p<0.001). The runoff score was also a weak independent predictor of 1-year assisted primary patency in these grafts (relative risk=1.9 for a score >4 in crural and a score >5.5 in pedal grafts, p=0.036). CONCLUSIONS: a completely occluded pedal arch in preoperative angiography was associated with poor infrapopliteal bypass outcome. Graft flow and maximal flow capacity are good predictors of the 1-year graft patency of femorocrural bypasses.