Per-operative topical administration of ZK 36 374 (Iloprost) acts favorably on patency of small artery anastomoses in rats

Appropriate Use of Intravenous Unfractionated Heparin after Digital Replantation: A Randomized Controlled Trial Involving Three Groups

BACKGROUND

The purpose of this study was to clarify the appropriate use of unfractionated heparin as an anticoagulation agent after digital replantation.

METHODS

This study was a prospective, randomized, single-blind, blinded-endpoint method, three-arm, parallel-group, controlled clinical trial conducted at a single institution. A total of 88 patients (101 fingers) following digital amputation and subsequent repair by anastomosis of both arteries and veins were randomly allocated into three groups: (1) control group (no heparin dose), (2) low-dose heparin group (10,000 IU/day), and (3) high-dose heparin group (start at 15,000 IU/day, then adjust the dose to achieve an activated partial thromboplastin time of 1.5 to 2.5 times the baseline). The outcomes were assessed regarding the proportion of success at 2 weeks after replantation of amputated digits, total or partial necrosis, and occurrence of complications.

RESULTS

No significant differences were found among the three groups, except for complications of congestion. The odds ratio of the heparin group compared with the control group for a success proportion was 5.40 (95 percent CI, 0.85 to 34.20; p = 0.027) in subjects aged 50 years or older. Significant elevations of activated partial thromboplastin time, aspartate transaminase, and alanine aminotransferase occurred in high-dose heparin groups on day 7.

CONCLUSION

Unfractionated heparin administration is considered effective for patients aged 50 years or older, although the routine use of unfractionated heparin is not necessary after digital replantation.

CLINICAL QUESTION/LEVEL OF EVIDENCE

Therapeutic, II.

[Evidence-based medicine and prevention of thrombosis in microsurgery. Critical review]

Prevention of thrombosis in microsurgery was the point of numerous publications without any referenced protocol. The question of this article was to know if it existed, for a patient who needed a microsurgical procedure, any medical treatment used, proved to lower the thrombotic risk. Using principles of evidence-based medicine, we observed that none of the medical treatments proved efficiency on preventing vascular thrombosis, arterial or venous. The low molecular weight heparins (LMWH) could be used on postoperatives to prevent the deep venous thrombosis of lower limbs but not to lower specially the microvascular thrombosis rate. Aspirin did not improve the positive rates and its adjunction to LMWH increased the bleeding. The evidence-based medicine, as we used it here, permits to conclude that the microsurgeon should not wait any miracle of the medical treatments. Until scientific studies prove efficacity of a treatment, the surgeon has to make a personal choice: keeping habits or following evidence-based medicine. The experience of the surgeon, of the anesthetist and of the paramedical team seem to be the main point to decrease the thrombotic risk during the multidisciplinary healing care of the patient.

Anticoagulation therapy in microsurgery: a review

The advent of microsurgical tissue transfer including replantation greatly has expanded the scope of reconstructive surgery. There are few recent innovations in anticoagulation therapies for microsurgery, however, and anastomotic thrombosis remains an occasional cause of surgical failure. No consensus exists on the ideal anticoagulation protocol for microsurgery. This article reviews major pharmacologic modalities of anticoagulation, delineates the mechanism of action and study of efficacy of each agent, and compares the risks and benefits of popular anticoagulation therapies. Finally, it examines available human outcomes-based data and attempts to provide a glimpse of the future direction of microsurgical anticoagulation research.

Iloprost and salvage of a free flap

Despite the alluring pharmacological properties of prostacyclin and its stable analogue (iloprost), these substances are little used in plastic surgery. A case is presented in which iloprost resulted in persistent patency of the vessels supplying a free flap. A patient who had had failure of a free flap because of thrombosis distal to the arterial anastomosis had a second free flap. Thrombus formed distal to the arterial anastomosis of the second flap and recurred when the anastomosis was redone. The flap was perfused with urokinase and then iloprost. After this, iloprost was given intravenously peroperatively and for 12 hours postoperatively. Postoperatively, the patient also received aspirin, ticlopidine and heparin. The flap survived without any late complications. A literature review offers confirmation of the advantages of using iloprost if microvascular anastomoses thrombose and during the reperfusion of flaps after prolonged ischaemia.

Adjuvant prostanoid treatment during femorodistal reconstruction

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)

Iloprost reduces peripheral resistance during femoro-distal reconstruction

A randomised placebo-controlled trial was conducted to investigate the effect of iloprost, a stable prostacyclin mimetic, on peripheral resistance during femoro-distal bypass. Patients undergoing femoro-distal long saphenous vein bypass for critical ischaemia received 3000 ng of iloprost or placebo infused into the graft via an unligated side branch over 2 min. Graft blood flow and peripheral resistance were measured for 20 min, using an operative Doppler flowmeter (OpDop 130, SciMed, U.K.) and a pressure transducer to record graft pressure. Postoperatively, graft blood flow was assessed by daily duplex ultrasound for 7 days. Iloprost produced an immediate drop in peripheral resistance in all cases (n = 18) by a mean (range) of 40% (4-80%) compared with controls (n = 15) in whom there was a 5.3% (-8 to +36%) increase in resistance (p less than 0.01, Wilcoxon test). Decreased peripheral resistance in iloprost-treated patients persisted to 20 min. The largest decreases in peripheral resistance occurred in patients with the highest initial resistances (r = 0.56, p less than 0.02). Graft flow during the same period increased by 52% (-7 to 294%) compared with controls in whom there was a 6% (-17 to 26%) increase in flow, (p less than 0.01). Flow remained elevated by 53% over baseline values at 1 week post-infusion in the iloprost-treated group but this did not achieve statistical significance compared to controls in whom flow also increased by 13%. 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.

Iloprost improves femoro-distal graft flow after a single bolus injection

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.

Femoro-distal graft flow augmentation with the prostacyclin analogue iloprost

The possible application of the prostacyclin analogue Iloprost to improve the results of arterial surgery has been studied. On completion of femoro-distal reconstruction, intra-graft administration of Iloprost caused an increase in graft blood flow measured by electromagnetic flowmetry. Three thousand nanograms of the drug appeared to be the optimum dose and in 10 patients who received this amount the graft blood flow increased from a mean of 117.6 ml/min to 225.5 ml/min (P less than 0.01, Wilcoxon), a mean (range) increase of 127.9% (54-190) after 20 min. Iloprost requires further evaluation, but may be a useful adjunct to femoro-distal reconstruction.