Acute increase in hepatic arterial flow during TIPS identified by intravascular flow measurements.

The purpose of this study was to investigate alterations of hepatic arterial flow during transjugular intrahepatic portosystemic stent shunt (TIPS) applying intravascular Doppler sonography. This prospective monocenter study included 25 patients with liver cirrhosis (alcohol induced [n = 19], chronic hepatitis associated [n = 3], primary biliary cirrhosis associated [n = 1], and cryptogenic [n = 2]) successfully treated with TIPS. All patients underwent intravascular hepatic arterial flow measurements during TIPS using an endoluminal flow sensor. The average arterial peak velocity (APV) and the maximum arterial peak velocity (MPV) were registered. Twenty-two patients (88%) showed increased APV, one patient (4%) showed unaffected APV, and two patients (8%) showed decreased APV after TIPS. The average portosystemic pressure gradient decreased significantly, from 22.0 +/- 5.1 mmHg before TIPS to 11.0 +/- 4.1 mmHg after TIPS (-50.0%; p < 0.0001). The average APV increased significantly, from 41.9 +/- 17.8 cm/s before TIPS to 60.7 +/- 19.0 cm/s after TIPS (+44.9%; p < 0.0001). The average MPV increased significantly, from 90.8 +/- 31.7 cm/s before TIPS to 112.6 +/- 34.9 cm/s after TIPS (+24.0%; p = 0.0002). These changes in perfusion set in within seconds after TIPS tract formation in all the patients with increased APV. We conclude that TIPS-induced portosystemic decompression leads to a significant increase in hepatic arterial flow. The changes occurred within seconds, suggesting a reflex-like mechanism.

Efficacy of a polyphosphazene nanocoat in reducing thrombogenicity, in-stent stenosis, and inflammatory response in porcine renal and iliac artery stents.

PURPOSE: It is hypothesized that the inorganic polymer poly[bis(trifluoroethoxy)phosphazene] (PTFEP) reduces stent-associated thrombosis, in-stent stenosis, and inflammatory response and stimulates reendothelialization in a porcine model. MATERIALS AND METHODS: PTFEP-nanocoated and bare stainless-steel stents (316 L) were implanted bilaterally in renal and iliac arteries of 16 minipigs (1, 4, and 12 weeks follow-up durations). Primary study endpoints were thrombogenicity determined by filling defects on angiography and in-stent stenosis assessed by lumen loss on quantitative angiography (ie, percentage stenosis) and light microscopy (ie, neointimal thickness, neointimal area, area stenosis). Secondary endpoints were inflammatory response and reendothelialization evaluated by light microscopy and scanning electron microscopy (SEM), respectively. RESULTS: Stent placement was successful in 32 renal and 26 iliac arteries. At follow-up, there were no thrombus depositions on PTFEP-coated renal and iliac stents. Thrombus depositions were found on two of six bare metal iliac stents after 4 weeks (P = .0651). PTFEP-coated stents showed a trend toward reduced in-stent stenosis in all renal and iliac arteries at all intervals: in iliac stents, neointimal area was significantly smaller in coated stents than in bare metal stents after 1 week and 4 weeks (P = .03 and P = .001, respectively). In renal arteries, inflammation scores indicated lower inflammatory response in PTFEP-coated stents than in bare metal stents after 1 week (P = .01). After 1 week, coated and bare metal stents exhibited complete reendothelialization on SEM. CONCLUSIONS: PTFEP-coated stents exhibited reduced thrombus deposition and a trend toward less in-stent stenosis and inflammatory response than bare metal stents.