Difference In Graft Patency Research Articles

Prospective randomized trial of woven versus collagen-impregnated knitted prosthetic Dacron grafts in aortoiliac surgery

Despite the theoretical advantages of coating knitted grafts with a material designed to reduce blood loss, their performance has not been directly compared with woven grafts in a prospective randomized trial. The aim of this study was to compare the graft handling qualities and operative blood loss of the two types of arterial prosthesis, as well as complication rate and patient survival at 1 year. A total of 267 consecutive patients having surgery for occlusive or aneurysmal disease of the aortoiliac arteries were randomized to receive woven (141 patients) or knitted collagen-impregnated Dacron (126 patients) grafts. Graft patency was assessed on discharge and at 1 year by duplex imaging. Mean(s.d.) intraoperative blood loss was statistically greater with woven grafts (1690(1424) ml) compared with knitted (1363(1172) ml) (P = 0.049). An insignificant 1-year increase in mean(s.d.) graft diameter of 1.2(0.2) mm was found at the distal anastomosis in the knitted group. There was no difference in graft patency between the groups and only one graft became infected. This study suggests that knitted and woven grafts have similar clinical performance and therefore the less expensive material (woven) should usually be selected unless haemorrhagic complications are anticipated.

Hemostatic effect of tranexamic acid (transamin) during coronary artery bypass grafting

The hemostatic effect of tranexamic acid (TA) was evaluated in patients undergoing coronary artery bypass grafting (CABG). The subjects were 33 serial patients who underwent elective CABG performed by the same team between January 1997 and April 2000. They were divided into a group that received TA (n=15) and a non-TA control group (n=18). The TA group received 50mg/kg of TA intravenously before starting cardiopulmonary bypass (CPB) and 25 mg/kg immediately after CPB. Blood loss from the end of CPB to completion of surgery (post-CPB), as well as during the first 6h (BL6), 6–12 h (BL6–12), 12–18h (BL12–18), and 18–24h after surgery (BL18–24), was compared between the two groups. The time of chest tube removal, the volume of blood transfused, and graft patency were also compared. The blood loss at BL6, BL6–12, BL12–18, and BL18–24, as well as the blood transfussion volume, were all significantly (P<0.05) lower in the TA group than in the control group. There was no significant difference in graft patency between the two groups. In CABG patients, TA reduced blood loss without affecting graft patency, suggesting that it is useful in this setting.

Worse clinical outcome but similar graft patency in women versus men one year after coronary artery bypass graft surgery owing to an excess of exposed risk factors in women

OBJECTIVESThis retrospective study sought to assess differences in graft patency and clinical outcome between women and men after coronary artery bypass graft surgery (CABG).BACKGROUNDA less favorable clinical outcome has been reported in women as compared with men. Its relation to graft patency has not been studied.METHODSWe analyzed one-year follow-up data of 912 patients (120 women) who entered a randomized clinical drug trial. All patients received vein grafts; in 494 patients (56 women) internal mammary artery (IMA) grafts were also used. Graft patency was assessed by coronary angiography at one year. Primary clinical end points were myocardial infarction, revascularization procedures and death; secondary clinical end points included recurrent angina, heart failure and arrhythmias.RESULTSOcclusion rates of vein grafts were 16.7% in women and 12.4% in men (odds ratio [OR] 1.62, 95% confidence interval [CI] 0.88 to 3.00, p = 0.12); occlusion rates of IMA grafts were 3.4% and 5.7% in women and men, respectively (OR 0.56, 95% CI 0.08 to 3.96, p = 0.56). Primary clinical end points were observed in 16.7% of women and 9.2% of men (OR 1.97, 95% CI 1.10 to 3.34, p = 0.022), and any clinical end point in 41.7% of women and 25.8% of men (OR 2.06, 95% CI 1.39 to 3.04, p = 0.0004). Myocardial infarction (15% vs. 7.6%, OR 2.15, 95% CI 1.24 to 3.75, p = 0.013) and recurrent angina (26.7% vs. 15.4%, OR 2.00, 95% CI 1.28 to 3.11, p = 0.004) occurred most frequently. Multivariate regression analysis did not identify gender as an independent risk factor for graft occlusion or the clinical end points. Graft occlusion was an independent predictor of the composite primary clinical end point (OR 2.75, 95% CI 1.59 to 4.75, p = 0.0003) and each of the secondary clinical end points. The observed differences were due to an imbalance of risk factors at baseline and to surgical and graft characteristics.CONCLUSIONSOne-year occlusion rates of vein and IMA grafts were comparable in women and men. Clinical outcome was related to graft patency and was less favorable in women owing to their uneven distribution of risk factors among both groups.

A prospective randomized multicentre comparison of expanded polytetrafluoroethylene and gelatin-sealed knitted Dacron grafts for femoropopliteal bypass

Purpose: To compare graft patency between expanded polytetrafluoroethylene (PTFE) and gelatin-sealed knitted Dacron for femoropopliteal bypass. Methods: A prospective, multicentre trial was performed in 108 patients randomized to receive either a PTFE or Dacron prosthetic graft. Distal anastomosis was above knee in 75 and below knee in 33 patients. Results: Primary patency at 1, 2 and 3 years was 72, 52 and 52% for PTFE, and 70, 56 and 47% for Dacron ( P=0.87). Secondary patency at 1, 2 and 3 years was 74, 54 and 54% for PTFE and 78, 70 and 53% for Dacron ( P=0.39). The most significant predictors of early graft failure were poor vessel run-off ( P=0.04) and critical limb ischaemia ( P=0.04). Conclusion: There was no difference in graft patency between PTFE and Dacron for femoropopliteal bypass.

Induction of Neointima Formation by Platelet Derived Angiogenesis Fraction in a Small Diameter, Wide Pore, PTFE Graft

Enhancement of endothelialization and patency of a small diameter (2 mm), wide pore, PTFE graft was attempted by coating the luminal surface with a platelet derived angiogenesis fraction (PDAF) and implanting it in a rat model. PDAF was delivered to the grafts by combining it with a carrier polymer. PDAF-treated grafts were initially implanted in the retroperitoneum for 21 days followed by removal of one for histology and in situ end to side bypass to the infrarenal aorta for the other. Vascularized grafts were examined at 14 days for patency and 100 days for patency and histology. Significant differences were noted in transmural ingrowth of capillaries and tissue at 21 days post implantation in PDAF-treated versus untreated grafts. Similarly, near significance was noted in capillary ingrowth and significance was noted in tissue ingrowth at 100 days in PDAF-treated grafts. Despite favorable trends particularly early in the time course, no significant differences in graft patency, endothelialization, or hydroxyproline content was demonstrated between PDAF-treated and untreated grafts. Results of this preliminary study are encouraging for further study of PDAF-treated PTFE grafts and the potential that rapid vascularized neointima formation results improved in graft patency rates.

Aspirin usage and its influence on femoro-popliteal vein graft patency

As part of the Femoro-popliteal Bypass Trial patients undergoing femoro-popliteal vein bypass were randomised to aspirin 300 mg and dipyridamole 150 mg twice daily or identical placebo tablets. Blood was taken from a subgroup of 145 patients (mean age 66.3 years) with patent grafts at 6 months. Serum salicylate analysis revealed that of the 65 randomised to receive placebo 18 (28%) had evidence of salicylate in their sample (greater than 50 ng ml-1). Similarly, in those randomised to active treatment and considered to be good compliers 16/61 (26%) had no evidence of salicylate in their serum sample (less than 50 ng ml-1). Analysis of primary graft patency by "intention to treat" failed to detect a difference by life table, the risk being slightly higher in the group assigned to placebo (RR = 1.33, 95% confidence internal C.I. 0.64-2.78, p = 0.438). When comparing patients with no detectable serum concentration (less than 50 ng ml-1) with patients with serum salicylate over 50 ng ml-1 there was a significant difference in graft patency at 66 versus 83% respectively at 3 years (RR = 2.38, 95%C.I. 1.08-5.26, p = 0.024). When corrected for a number of possible risk factors this significant difference was maintained (RR = 2.78, 95%C.I. 1.15-6.67, p = 0.017). Although these findings are based on observational data they provide indirect evidence of an improvement in graft patency with aspirin. This result combined with the finding of a significant reduction in cardiovascular events in the main trial results support the use of aspirin and dipyridamole in patients undergoing femoro-popliteal vein bypass.

The Acute and Chronic Effects of G-Lasing on Femoral Vein Grafts in Dogs

Each year, 5% of all coronary artery bypass operations are repeat procedures, and 15%-30% of coronary artery vein grafts occlude within the first eighteen months postoperatively. To evaluate the macroscopic and histologic effects of G-lasing on vein grafts and their patency, femoral veins were used to bypass bilaterally induced stenoses of femoral arteries in 10 dogs. The left vein grafts were G-lased with a 1.5 mm, hot-tipped argon laser at 5 watts for ninety seconds, while the right grafts were used as the controls. Acutely, each vein graft demonstrated no evidence of charring or perforation. The percentage of endothelium present in the G-lased vein grafts was consistently less than 5%, whereas the control vein grafts had an average of 70%. After ten weeks, the animals were sacrificed, and the vein grafts were evaluated for histologic changes and patency. There were no significant microscopic differences between the G-lased and control vein grafts. A statistically significant difference in graft patency was not achieved between G-Lased and control vein grafts at 10 weeks, but only a small number of grafts were studied. Further studies will be needed to evaluate the effects of G-lasing on the long-term patency of vein grafts.

Intraoperative angioplasty and coronary artery bypass grafting for the treatment of multisegmental coronary artery disease.

This report summarizes our experience with intraoperative angioplasty and coronary artery bypass graft surgery for the treatment of multisegmental coronary artery disease. The indication for intraoperative angioplasty was the presence of diffuse, symptomatic, coronary artery disease with at least one coronary artery having two or more areas of narrowing. The balloon catheter was introduced through an arteriotomy and advanced through the point of obstruction. The balloon was then inflated to 6 atmospheres for 15-20 seconds. This procedure was repeated two to three times. The time required for this technique averaged less than 5 minutes. Although there were no documented intraoperative perforations, intimal injuries were observed in two patients at the time of postoperative catheterization. Early and late postoperative angiograms showed that approximately 30% of angioplastied vessels had an improvement in their dilated lesions. Patients with discrete areas of narrowing had greater improvement in luminal diameter than those with diffuse narrowing (49% versus 17%). There was no difference in graft patency or left ventricular wall motion between vessels that did or did not undergo angioplasty.

Platelet inhibitors versus anticoagulants for prevention of aorto-coronary bypass graft occlusion

The effects of the antiaggregant substance ticlopidine and of the anticoagulant acenocoumarol on patency rates of aorto-coronary bypass grafts were compared in a prospective randomized trial. Ticlopidine, 250 mg b.i.d. was administered orally from the first postoperative day till angiography, while anticoagulation with acenocoumarol was initiated on the second to third postoperative day. Side-effects of ticlopidine were rare and patient management with the standard dosage of this drug was easier than oral anticoagulation. From an initial group of 166 randomized patients 149 completed the trial by coronary angiography three months postoperatively. The 78 patients in the ticlopidine group showed a compliance of 85%. The average prothrombin time in the 71 patients receiving acenocoumarol was 26.9%. Detailed statistical analysis of the two study groups revealed no reason to doubt the correctness of randomization. Coronary angiography showed an average patency rate per patient of 84% with ticlopidine and of 82% with acenocoumarol. This and various other measures of graft occlusion did not reveal any substantial difference in graft patency of patients receiving ticlopidine or acenocoumarol. It is concluded that ticlopidine may well be used instead of anticoagulants for prevention of postoperative occlusion of aorto-coronary bypass grafts.

Prospective randomized study of concomitant lumbar sympathectomy with aortoiliac reconstruction

Ninety-three consecutive patients for aortofemoral bypass grafting were studied to determine the effect of sympathectomy on early and late patency, the need for subsequent distal procedures, amputation rate, and ankle-brachial Doppler systolic pressure indexes. Sixty-seven patients completed the study. Fifty-three limbs were randomized to receive sympathectomy and 81 no sympathectomy. The mean length of follow-up postoperatively was 11 ± 2.53 months (maximum 24). Five grafts occluded, two early and three late. Both early occlusions occurred in the nonsympathectomy group and all three late occlusions ensued in the sympathectomy group. Subsequent distal procedures were necessary early (within 30 days) in five limbs, all in the nonsympathectomy group. Nine limbs required distal procedures late, four (5 percent) in the nonsympathectomy group and five (9.5 percent) in the sympathectomy group (p > 0.05). Altogether, distal bypass was required in 11 percent of the patients in the nonsympathectomy group versus 9.4 percent in the sympathectomy group (p > 0.05). Five limbs were amputated 4 to 14 months after aortofemoral bypass, four (5 percent) in the nonsympathectomy and one (2 percent) in the sympathectomy group (p > 0.05). The ankle-brachial pressure index increased significantly after aortofemoral bypass in both groups (p < 0.05). The mean increase after aortofemoral bypass was more marked in the sympathectomy group (p > 0.05). Thus, at a mean follow-up time of 11 months after aortofemoral bypass, there was no significant difference in graft patency, need for subsequent distal bypass, or amputation rate between the sympathectomy and nonsympathectomy groups.

Graft replacement in venous system.

1. Correlation between hemodynamics in different parts of venous system and difference in graft patency was discussed. 2. Feasibility of compilation graft made of autogenous vein and Teflon tube with external support was evaluated in experimental replacement of canine superior vena cava. 3. Clinical trial of this compilation graft would appear to be worth while.