Vascular occlusions in the lower limbs require a bypass operation. A conduit is needed for the bypass operation. Autogenous vein graft from the contralateral limb or ipsilateral limb is considered as an ideal conduit for the bypass operations. But it is not available or inadequate in 20-30% of the patients requiring bypass operation. Then one has to use the synthetic vascular graft in the absence of autogenous vein graft. The synthetic vascular grafts are modified over a period of time to improve the patency and reduce the recurrent thrombosis and also reduce the need for reinterventions. Porous dacron grafts need preclotting and that is not needed in the PTFE grafts. The kinking and rotation of the synthetic grafts in the long subcutaneous tunnels is avoided by external support (rings/spirals). In a similar way there were many attempts to make the inner surface of the graft less thrombogenic and heparin bonding (coating) was one of them. These grafts have initially shown better results in the literature and they are available in the market. But there were not many papers to establish the indications and evaluating the long term results. Now these vascular grafts are also used for creating AV fistula for patients requiring hemodialysis and known as arterio-venous grafts. The long term patency of the A-Vgrafts without re-interventions is a boon for the patients. It was hoped that the heparin bonding to the internal luminal surface of the Arterio-Venous grafts may prevent the thrombosis.
Recently a paper is published saying that Heparin Bonding Does Not Improve Patency of Polytetrafluoroethylene Arterio-Venous Grafts by Matthew TA et al (Feb 2013). A total of 223 patients had 265 grafts placed. Of these, 62 (23%) were hepPTFE grafts. The average age was 66 ± 15 years in the hepPTFE group and 59 ± 17 years in the non–heparin-bonded control group (PTFE; P < 0.01). Of the hepPTFE group, 39% were men, 81% were African American, 63% were diabetic, and 81% had a tunneled catheter at the time of access placement. Of the PTFE group, 35% were men, 85% were African American, 56% were diabetic, and 83% had a tunneled catheter. HepPTFE grafts failed to improve rates of primary, assisted primary, or secondary patency based on univariate analysis (hazard ratio [HR]: 1.37 [95% confidence interval {CI}: 0.99–1.88]; HR: 1.39 [95% CI: 0.98–1.96]; and HR: 1.20 [95% CI: 0.73–1.96], respectively). The number of secondary interventions was similar in the 2 groups (1.1 interventions per person-year of follow-up PTFE versus 1.4 hepPTFE; P = 0.13). A multivariable model including age, diabetes, peripheral artery disease, tobacco use, previous access placement, and tunneled catheter found that the HR for hepPTFE was not significantly different than PTFE in primary, assisted primary, or secondary patency (HR: 1.32 [95% CI: 0.91–1.90]; HR: 1.35 [95% CI: 0.91–1.99]; and HR: 1.15 [95% CI: 0.62–2.16], respectively.
This probably indicates that the intraluminal thrombosis of Arterio-Venous Grafts (AVGs) in the patients undergoing Dialysis is dependent on many other factors other than less thrombogenisity of the intraluminal surface of the grafts.
Recently a paper is published saying that Heparin Bonding Does Not Improve Patency of Polytetrafluoroethylene Arterio-Venous Grafts by Matthew TA et al (Feb 2013). A total of 223 patients had 265 grafts placed. Of these, 62 (23%) were hepPTFE grafts. The average age was 66 ± 15 years in the hepPTFE group and 59 ± 17 years in the non–heparin-bonded control group (PTFE; P < 0.01). Of the hepPTFE group, 39% were men, 81% were African American, 63% were diabetic, and 81% had a tunneled catheter at the time of access placement. Of the PTFE group, 35% were men, 85% were African American, 56% were diabetic, and 83% had a tunneled catheter. HepPTFE grafts failed to improve rates of primary, assisted primary, or secondary patency based on univariate analysis (hazard ratio [HR]: 1.37 [95% confidence interval {CI}: 0.99–1.88]; HR: 1.39 [95% CI: 0.98–1.96]; and HR: 1.20 [95% CI: 0.73–1.96], respectively). The number of secondary interventions was similar in the 2 groups (1.1 interventions per person-year of follow-up PTFE versus 1.4 hepPTFE; P = 0.13). A multivariable model including age, diabetes, peripheral artery disease, tobacco use, previous access placement, and tunneled catheter found that the HR for hepPTFE was not significantly different than PTFE in primary, assisted primary, or secondary patency (HR: 1.32 [95% CI: 0.91–1.90]; HR: 1.35 [95% CI: 0.91–1.99]; and HR: 1.15 [95% CI: 0.62–2.16], respectively.
This probably indicates that the intraluminal thrombosis of Arterio-Venous Grafts (AVGs) in the patients undergoing Dialysis is dependent on many other factors other than less thrombogenisity of the intraluminal surface of the grafts.
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