iloprost and Graft-Occlusion--Vascular

This study is planned bringing about a new choice for the prophylaxis of RA spasm which is topical iloprost and compares its efficacy with papaverine and diltiazem.. Twenty eight CABG patients with RA grafts were categorized into four groups by taking into account the topical vasodilator (papaverine, diltiazem, iloprost and saline) that was utilized during harvesting. Arterial segments were separated into four rings and were than soaked with KCL, norepinephrine, phenylephrine and serotonin. Then, acetylcholine was given to induce relaxation and the preparations were put to rest for 10 minute.. The contraction response achieved by the vasoreactive agents was most effectively inhibited by papaverine. The effectiveness of the response obtained by iloprost was similar to that of papaverine and significantly stronger than that of diltiazem. Especially at high vasoreactive substance concentrations, diltiazem had a contraction close to that of the control while the protective effect was weaker than those of papaverine and iloprost.. Iloprost can be recommended as a strong alternative to the topical agents used for preventing arterial graft spasm.

Topics: Administration, Topical; Aged; Arterial Occlusive Diseases; Coronary Artery Bypass; Diltiazem; Dose-Response Relationship, Drug; Female; Graft Occlusion, Vascular; Humans; Iloprost; Male; Middle Aged; Norepinephrine; Papaverine; Phenylephrine; Potassium Chloride; Radial Artery; Serotonin; Spasm; Tissue and Organ Harvesting; Treatment Outcome; Vasoconstriction; Vasoconstrictor Agents; Vasodilator Agents

A prospective randomized placebo-controlled trial was conducted to determine the effects of the stable prostacyclin analogue iloprost on early graft patency and hemodynamic parameters during femorodistal reconstruction for critical leg ischemia. Peripheral resistance and graft blood flow were measured using an operative Doppler flowmeter and graft pressure transducer. Postoperative graft surveillance was continued at 1-month and then at 3-month intervals by duplex Doppler ultrasonography, measurement of ankle-brachial pressure indices, and intravenous digital subtraction angiography when indicated. In patients receiving 3000 ng of iloprost (n = 45) infused into the graft on completion there was an immediate mean decrease in peripheral resistance of 44% that persisted to skin closure in comparison with controls (n = 38) in whom no such decrease in resistance occurred (p < 0.001, Wilcoxon test). During the same period, mean graft blood flow increased in iloprost-treated patients by 74.5% compared with controls in whom there was a 6% increase in flow (p < 0.001). Primary cumulative patencies at 1 month were significantly higher in iloprost-treated grafts, 98% compared to 83% for controls (p < 0.05, log-rank test). Cumulative primary patencies at 1 year and secondary patencies at 1 month and 1 year were also greater in the iloprost-treated group (67%, 98%, and 87.6%, respectively) compared to controls (65%, 86%, and 79.3%, respectively), but these did not achieve statistical significance. A single bolus infusion of iloprost has prolonged beneficial effects on graft blood flow and peripheral resistance during femorodistal reconstruction. This is reflected by improved early primary graft patencies.(ABSTRACT TRUNCATED AT 250 WORDS)

Topics: Adult; Aged; Aged, 80 and over; Blood Flow Velocity; Female; Femoral Artery; Graft Occlusion, Vascular; Humans; Iloprost; Intraoperative Period; Ischemia; Leg; Male; Middle Aged; Prospective Studies; Saphenous Vein; Vascular Patency; Vascular Resistance

A randomised placebo-controlled trial was conducted to investigate the effects of iloprost, a stable prostacyclin analogue, on peripheral resistance, during femoro-crural arterial bypass. 3000 ng of iloprost, infused into the graft, produced an immediate drop in peripheral resistance by a mean (range) of 43% (4-80%; p less than 0.01, Wilcoxon). Decreased peripheral resistance persisted to 20 minutes. Graft flow during the same period increased by 59.8% (-7 to 294%; p less than 0.01) and this increase persisted after the operation. Iloprost produces an immediate decrease in peripheral resistance associated with a prolonged increase in graft blood flow. This may reduce graft failure in the early postoperative period.

Topics: Aged; Aged, 80 and over; Blood Flow Velocity; Combined Modality Therapy; Female; Foot; Graft Occlusion, Vascular; Humans; Iloprost; Ischemia; Male; Middle Aged; Saphenous Vein; Vascular Resistance

A double-blind, randomised, placebo-controlled trial was conducted to study the effect of the stable prostacyclin analogue iloprost on femoro-distal graft blood flow. After completing femoro-distal reconstruction, 3000 ng of iloprost or placebo was injected into the graft over 2 min. Graft blood flow, measured by electromagnetic flowmetry, increased by a mean (range) of 94% (12 to 192%) in patients receiving iloprost (n = 15) compared to 6% (-34 to 53%) in controls (n = 16; p less than 0.0001, t-test). Increased graft flow, measured by duplex ultrasound, was maintained in the iloprost group over a 7 day period postoperatively (F = 5.2, p = 0.03; analysis of variance) and remained higher at 7 days (p = 0.007, t-test). Iloprost produces an immediate, sustained increase in graft blood flow after femoro-distal reconstruction and may therefore be of benefit in reducing the incidence of early graft failure.

Topics: Aged; Arteriovenous Shunt, Surgical; Blood Flow Velocity; Double-Blind Method; Female; Femoral Artery; Graft Occlusion, Vascular; Humans; Iloprost; Male; Regional Blood Flow; Saphenous Vein

Vascular prostheses of small diameter perform poorly in vivo, in part because of the high thrombogenicity of available biomaterials. This study examined the thrombogenicity of expanded polytetrafluoroethylene (ePTFE) vascular graft segments (10 mm long x 4 mm i.d.) in vitro before and after impregnation with saline, alginate, or alginate containing the stable prostacyclin analog, iloprost. Each segment was immersed in activated whole blood and the weight of the adherent thrombus was measured at specified intervals. At 6 and 7 min the saline-denucleated group accumulated significantly less thrombus than control (p < .05). Alginate alone was not significantly different from controls. The graft segments treated with alginate + iloprost accumulated significantly less thrombus (p < .05) than all other groups after 6 min. These data demonstrate that denucleation of ePTFE with iloprost in alginate dramatically decreases its in vitro thrombogenicity.

Topics: Alginates; Biocompatible Materials; Blood Vessel Prosthesis; Glucuronic Acid; Graft Occlusion, Vascular; Hexuronic Acids; Humans; Iloprost; Platelet Aggregation Inhibitors; Polytetrafluoroethylene; Thrombosis

To test the thrombosis resistance of a vascular prosthesis coated with antithrombogenic agents, we evaluated a small vessel prosthesis of expanded polytetrafluoroethylene (ePTFE) implanted in the rat aorta and removed 1 week following surgery. Control grafts consisted of 1 mm internal diameter ePTFE. Experimental grafts consisted of 1 mm internal diameter ePTFE noncovalently bonded to tissue plasminogen activator (tPA) and iloprost using the surfactant tridodecylmethylammonium chloride. After 1 week the grafts were harvested, patency was determined, and histologic specimens were prepared for electron microscopy. Six of 10 control grafts were thrombosed, whereas 9 of 10 tPA-iloprost-bonded grafts were patent (p < 0.03). Of concern, there was an unexpectedly high mortality rate in the tPA-iloprost group compared to the control group among animals that died before completion of the study. Evaluation of the safety of these drugs must, therefore, be an early component of future experiments. Nevertheless, these studies indicate that a small vessel prosthesis bonded to tPA and iloprost may ameliorate some of the complications associated with early graft failure.

Topics: Animals; Aorta, Abdominal; Blood Vessel Prosthesis; Graft Occlusion, Vascular; Iloprost; Male; Microscopy, Electron, Scanning Transmission; Polytetrafluoroethylene; Prosthesis Failure; Quaternary Ammonium Compounds; Rats; Rats, Sprague-Dawley; Surface-Active Agents; Thrombosis; Tissue Plasminogen Activator; Vascular Patency

Cellular injury is a major cause of intimal hyperplasia in vein grafts. The effects of exposure of vein samples to iopamidol, papaverine and iloprost were studied in vitro in an organ chamber to determine whether these agents cause endothelial and/or smooth muscle cell injury. Smooth muscle cell function was assessed by eliciting a dose response curve to noradrenaline. Endothelial cell function was assessed by measuring the degree of endothelial-dependent relaxation of sub-maximally contracted vein samples. Iopamidol and iloprost did not have any deleterious effect on endothelial or smooth muscle cell function. Papaverine did not affect endothelial-dependent relaxation but did produce a significant decrease in smooth muscle contraction. The use of these intraoperative agents during femorodistal bypass does not appear to cause functional injury to the endothelial or smooth muscle cells.

Topics: Aged; Blood Vessel Prosthesis; Dose-Response Relationship, Drug; Endothelium, Vascular; Graft Occlusion, Vascular; Humans; Iloprost; In Vitro Techniques; Iopamidol; Middle Aged; Muscle, Smooth, Vascular; Norepinephrine; Papaverine; Saphenous Vein

The ability of prostacyclin analogue incorporated into a controlled-release suture to prevent postoperative venous thrombosis was investigated. Thirteen rats underwent bilateral transection and anastomosis of the common femoral vein. In each animal, polycaprolactone suture containing 0.25 micrograms/cm of the prostacyclin analogue Iloprost (Schering Ag, Berlin, West Germany) was used to perform the anastomosis on one vessel. Similar suture without prostacyclin analogue was used on the contralateral vessel, which served as a control. Functional patency and luminal surface morphology were assessed 24 hours postoperatively. All anastomoses performed using suture containing prostacyclin analogue were patent. Among controls, five anastomoses were patent and eight were occluded. This difference was highly significant (p less than 0.005). All anastomoses performed with prostacyclin analogue-containing suture exhibited a uniform absence of thrombosis. In contrast, eight control veins exhibited a dense, well-organized fibrinous clot that filled the entire lumen, effectively sealing off the vessel. These results suggest that the prostacyclin analogue released from the suture was highly effective in inhibiting thrombus formation without adversely affecting the vessel's ability to achieve hemostasis.

Topics: Animals; Epoprostenol; Graft Occlusion, Vascular; Iloprost; Male; Postoperative Complications; Rats; Rats, Inbred Strains; Sutures; Thrombophlebitis