Streptokinase in the treatment of acute arterial occlusion of the hand

The role of thrombolytics in acute and chronic occlusion of the hand

Distal arm and hand ischemia from vessel thrombosis or embolism remains a difficult clinical challenge. The causes of ischemia are variable and include connective tissue disease, embolism, atherosclerosis, and iatrogenic etiology. Although reports are limited, treatment with catheter-directed thrombolysis has favorable results in cases of acute thrombosis, with most patients (80%) demonstrating improvement. Digital amputation rates are less than 10% and the hand is often salvaged. Bleeding and access-site complications remain prevalent in patients undergoing intra-arterial thrombolysis. This review discusses etiology, treatment approaches, outcomes, and complications when thrombolytic therapy is used for distal arm and hand ischemia.

Ischemia of the hand secondary to radial artery thrombosis: A report of three cases

Upper extremity arterial thrombosis, though rare, is more prevalent on the ulnar side of the circulation, with the most common etiology being repetitive blunt trauma to the hypothenar eminence. Radial artery thrombosis is even more rare and when it does occur, is associated most often with iatrogenic cannulation, producing subsequent thrombi and emboli. Three cases of spontaneous thrombosis of the radial artery extending to the superficial palmar arch and the princeps pollicis artery are presented here. Two patients underwent thrombectomies and one underwent excision of the thrombosed segment and reconstruction with a reversed saphenous vein graft. The etiology of the thrombus was consistent with cancer in two cases and trauma in one.

Acute arterial occlusions of the small vessels of the hand and forearm: treatment with regional urokinase therapy

PURPOSE

Arterial occlusions of the small vessels of the forearm and hand may have the same consequences as arterial occlusions in the distal lower extremity. There is limited reported experience with the regional thrombolytic therapy in this setting. The authors reviewed their experience with thrombolytic therapy in acute and subacute arterial occlusions of the distal upper extremity to further clarify its role.

MATERIALS AND METHODS

Twelve patients with acute or subacute arterial occlusions of the forearm and hand who had ischemic digits and were treated with regional urokinase infusion were identified retrospectively. Their medical and radiology records were reviewed.

RESULTS

All 12 patients demonstrated angiographic improvement and 11 patients demonstrated clinical improvement after treatment. Tissue necrosis in four patients led to partial amputation of one digit in two patients and three digits in two patients. Three of these patients had category III ischemia at presentation. The level of resulting amputation was altered in all but one patient. Vasospasm was noted frequently but responded to vasodilators. No significant complications occurred.

CONCLUSIONS

When therapeutic alternatives are limited to anticoagulation and expectant amputation, regional urokinase infusion can optimize distal runoff, obviate or improve the options for distal surgical bypass, and limit tissue loss.

Prevention of microvascular thrombosis by topical application of recombinant tissue factor pathway inhibitor

Tissue factor pathway inhibitor is a naturally occurring protein inhibitor of factor X and the tissue factor-factor VII complex of the extrinsic pathway of coagulation. The potential of tissue factor pathway inhibitor as a topical antithrombotic agent was evaluated in a rabbit model of thrombosis that combined intimal injury, anastomosis, and a twisted pedicle. In 207 rabbit ears, a near-complete amputation was performed, preserving the central ear artery and vein. The central ear artery was transected, the intima was removed mechanically over a 1-cm length, the artery was anastomosed, and the ear was twisted 360 degrees, wrapping the intact vein around the artery. Before recirculation, the lumen was irrigated on a blinded, randomized basis with either hirudin (100 or 500 units/ml), heparin (50 or 100 units/ml), tissue factor pathway inhibitor (10, 40, 125, or 250 microgram/ml), heparin and tissue factor pathway inhibitor together, or vehicle (control). Upon arterial reflow, the ears were observed for 7 days. Patency rates after 7 days were as follows: hirudin, 30 and 55 percent; heparin, 43 and 50 percent; tissue factor pathway inhibitor, 75 and 90 percent; heparin and tissue factor pathway inhibitor, 75 percent; and vehicle, 6 percent. The higher concentrations of tissue factor pathway inhibitor led to significantly higher patency rates than heparin, hirudin, or control solutions. Electron microscopic evaluation of specimens irrigated with gold- labeled tissue factor pathway inhibitor revealed the inhibitor bound to the injured intimal surface for at least 3 days postoperatively. Coagulation studies showed no change in the clotting profile upon intravascular infusion with tissue factor pathway inhibitor even at the highest dose used topically. We conclude that tissue factor pathway inhibitor is a more effective topical antithrombotic agent than either heparin or hirudin.

Late salvage of a "free flap" phalloplasty: a case report

Three weeks after radial forearm free flap phalloplasty, a 28-year-old female-to-male transsexual presented with ischaemia of the neophallus. A salvage procedure was started 7 hours after onset of ischemia. Thrombectomy of the arterial pedicle did not result in venous return of the arterial inflow. Perfusion of the flap with streptokinase restored venous return. Flap perfusion was confirmed by intraoperative direct angiography of the neophallus. Six months after this salvage procedure, the flap is doing well and tactile sensibility has occurred.

Antithrombotic benefit of subendothelium-bound urokinase: an experimental study

To improve the outcome of extremity replantation, microsurgeons have administered systemic antithrombotic agents (e.g., heparin, aspirin, dextran). To obviate the risks associated with systemic anticoagulation, we have investigated the use of topically applied urokinase for its binding capacity to arterial subendothelium and for its ability to prevent subsequent thrombosis. An arterial model of thrombosis associated with intimal deendothelialization was developed. Donor rat carotid arteries were everted and mechanically deendothelialized with a scalpel blade. The vessels were next subjected to one of several treatments, which included 30-minute incubation with urokinase, heparin, or vehicle (lactated Ringer's solution). The vessels were then washed, reinverted to normal orientation, sectioned into 5 mm lengths, and grafted into the femoral arteries of recipient rats. Two-hour patency rates were 25% for controls (n = 20), 10% for heparin-treated vessels (n = 10), and 55% for urokinase-treated vessels (n = 20); this last was significantly greater than the other two groups. In vitro investigations revealed that urokinase has a high capacity for binding to subendothelium, with a release half-life of approximately 20 minutes. Surface-bound urokinase was found to have proteolytic activity similar to that of urokinase in solution. These results indicate that urokinase may be a more beneficial irrigating solution additive than heparin for repair of traumatized vessels.

Acute and chronic ischemia of the hand: pathophysiology, treatment, and prognosis

Fifty consecutive patients with acute and chronic ischemia of the hand were investigated by Allen testing, Doppler ultrasound, digital plethysmography, and angiography over a 4-year period. The pathophysiologic mechanism responsible for the ischemia was determined to be emboli in 6%, vasospasm in 10%, thrombosis or "sludging" in 28%, occlusive disease in 26%, and occlusive disease associated with either vasospasm or external compression in 30%. Ten patients required emergency medical treatment with intraarterial streptokinase, intravenous heparin, or dextran 40 and continuous stellate ganglion blocks, and three patients required emergency microsurgical revascularization because of radial artery thrombosis. Patients with chronic ischemia of the hand were maintained on nifedipine, 30 to 60 mg daily, and pentoxifylline, 1200 mg daily. Seven patients underwent digital sympathectomy and 14 patients underwent microsurgical revascularization as prophylactic procedures for chronic digital ischemia. Amputations were required in 18 patients because of end-stage gangrene. Long-term follow-up revealed a 20% incidence of recurrent digital ulcerations. There have been six deaths during follow-up, five of them due to myocardial infarction; this reflects the underlying systemic arteriopathy in many of these patients.

Extensive thromboembolic disease of the hand and forearm: treatment with thrombolytic therapy

Six patients with extensive hand and forearm thromboembolic disease were treated by means of intraarterial infusion of urokinase, with good clinical results. Four significant complications occurred, including a possible stroke. Embolization of pericatheter thrombus was a possible etiologic factor in this case. Antegrade brachial artery puncture should be used in the setting of prolonged upper extremity thrombolytic therapy to avoid the cerebral vasculature. Thrombolysis is an effective technique for tissue salvage in cases of inoperable hand thrombosis.

Selective heparinization of venous anastomosis in latissimus dorsi free flaps to cover lower-extremity soft-tissue defects

Two groups of consecutive patients treated with latissimus dorsi free myocutaneous flaps to cover lower-extremity soft-tissue defects were compared for postoperative vascular occlusion. In the first group of 13 patients (group I), there were five (38%) venous occlusions and no arterial occlusions. The second group of 15 patients (group II) was treated with selective heparinization of each venous anastomosis via a 0.35" catheter sutured into the serratus branch of the donor vein. In this group one patient suffered an arterial occlusion, but no patient suffered a venous occlusion. Statistical analysis using the Fisher exact probabilities test showed a significant decrease in vascular occlusion rate in group II, proving that selective heparinization had a beneficial effect on the venous patency rate.

Topically applied antithrombotic agents offer a new therapeutic approach to the prevention of microvascular thrombosis

In the quest to develop optimal antithrombotic therapies for reconstructive microsurgery, with concomitant minimization of patient risk for generalized hemorrhage, surgeons have been turning to localized intraarterial delivery of various agents. An extension of this direction is to design agents that bind specifically to the site of thrombogenesis and effectively inhibit or prevent the buildup of thrombotic components. Progress in this direction must make use of the latest developments in the molecular understanding of coagulation, platelet adhesion/aggregation, and fibrinolytic processes. This article reviews pertinent developments in the biochemical understanding of thrombosis and discusses current avenues of investigation in the development of topically applied agents that help prevent microvascular thrombotic occlusion.

The role of thromboxane in experimental inadvertent intra-arterial drug injections

Inadvertent intra-arterial injection of drugs produces a well-defined clinical syndrome whose pathophysiology remains unclear. This study was designed to determine the role of the inflammatory mediator, thromboxane, in intra-arterial drug injections. The rabbit ear model, as described by Kinmonth and Sheppard, was used. Five of the experimental groups were treated with specific or nonspecific thromboxane blocking agents and two groups served as controls. Immunohistochemical staining of the control ears showed elevated levels of thromboxane within the first 6 hours postinjury. The specific thromboxane blocking agents, methimazole and Aloe vera, showed almost complete blockade of thromboxane production. The percentage of ear survival was significantly greater in the group treated with topical Aloe vera (p less than 0.05) and even greater survival was achieved in the combined Aloe vera/methimazole group (p less than 0.01). On the basis of these results, we have begun treatment of such injuries with specific and nonspecific thromboxane blocking agents.