A Comparative Histopathological Study of Heparin Coated and Uncoated Polytetrafluoroethylene Shunts in Children With Congenital Heart Defect

Recently, heparin coated polytetrafluoroethylene (PTFE) shunts are available and are believed to improve inherent shunt problems such as thrombosis and excessive and incomplete neointima formation or occlusion. We aimed at comparing the potential histopathological differences in the neointima (in) between uncoated (UCS) PTFE shunts and heparin coated (HCS) PTFE shunts. Thirteen shunts (six UCS and seven HCS) were analyzed. The specimens were fixed in formalin, embedded in paraffin or in methylmethacrylate, and characterized by standard and immunohistochemical staining. The thickness of pseudointima proliferation was graded as follows: 0 = no cell layers, 1 = few layers <100 µm, 2 = partial layers >100 µm, 3 = complete layers <300 µm, 4 = complete layers >300 µm, and 5 = occlusion. Mean shunt size was 3.4 ± 0.2 mm in UCS and 3.1 ± 0.2 mm in HCS (P = .053). Mean time of implantation was 163 ± 75 days in UCS and 97 ± 52 days in HCS (P = .091). There were no significant differences in the proportion of patients with functionally single ventricle, body surface area, age at implantation, or implantation type, between both groups. Shunt occlusion did not occur. Unplanned shunt explantation due to cyanosis was performed in one patient in each group. Partial thrombus formation was observed in one UCS (P = .462). There was complete endothelialization in 50% of UCS and 86% of HCS (P = .266). The grade of pseudointima proliferation was 1.8 ± 0.4 in UCS and 1.7 ± 0.5 in HCS (P = .646). The histopathological workup of PTFE shunts revealed equally partial endothelialization and discrete pseudointima proliferation in both the groups. The process of endothelialization may be faster in HCS.