Treatment of peripheral arterial obstruction with streptokinase: results in arterial vs graft occlusions

Percutaneous Local Arterial Thrombolytic Infusion

All complications occurring in 55 local thrombolytic infusions performed for (sub)acute limb ischemia using streptokinase (SK) in 22 procedures and urokinase (UK) in 33 procedures were recorded. Success was achieved in 74.5% of the procedures. Major complications occurred in 31.8% of the procedures using SK, and in 12.1% of the procedures using UK (p = 0.07). Hemorrhage was the most common major complication and occurred in 27.2% of SK procedures and in 9.0% of UK procedures, a difference which was not significant. Overall, 30 day mortality was 16.3% and procedure-related death was 1.8%. Moderate complications necessitating only the adjustment of drug regimen and minor complications without consequence were observed in 45.5% and 45.5%, respectively, of the SK procedures, and in 57.6% and 66.7% of the UK procedures.

Intra-arterial catheter directed therapy for severe graft-versus-host disease

Graft-versus-host disease (GVHD) is a major complication of allogeneic bone marrow transplantation (BMT), resulting in death in the majority of steroid-resistant patients. We assessed the efficacy of regional intra-arterial treatment in patients with resistant hepatic and/or gastrointestinal (GI) GVHD. In total, 15 patients with steroid resistant grade 3-4 hepatic (n = 4), gastrointestinal (GI) (n = 8) GVHD or both (n = 3) were given intra-arterial treatment. Patients with hepatic GVHD received methotrexate and methylprednisolone into the hepatic artery. Patients with GI GVHD were treated with infusions of methylprednisolone into the superior and inferior mesenteric arteries. Two patients with pronounced upper GI symptoms also received upper GI treatment. In total, 25 procedures were carried out (range 1-3 per patient). Hepatic response was observed in four out of seven (57%) patients with hepatic GVHD, three (43%) featuring good response. Complete responses were observed in nine (82%) GI GVHD patients, with median time to initial and complete response of 3 d (range 1-7) and 15.8 d (range 4-33) respectively. Regional treatment of severe GVHD with intra-arterial treatment appears to be effective and safe. GI treatment maybe more effective than intrahepatic treatment. Early administration of isolated intra-arterial therapy in high-risk patients may further improve the outcome and reduce untoward effects of systemic immunosuppressive treatment.

The case for better research standards in peripheral thrombolysis: poor quality of randomized trials during the past decade

RATIONALE AND OBJECTIVES

We assessed how well published randomized controlled trials (RCTs) of peripheral thrombolysis have been designed and how they adjusted for patient characteristics that may influence responses to therapy.

METHODS

RCT studies published between 1984 and 1994 were reviewed to determine whether they included nine crucial elements: sample size calculations, description of unenrolled eligible participants, homogeneous samples, balanced experimental groups, equal potency therapies, equal follow-up of outcomes, appropriate statistical inference, multivariable or subgroup analyses, and anonymous review of subjective endpoints.

RESULTS

The nine RCTs complied with a median of three of nine standards (range = 2-6). Each report exhibited serious flaws that may affect generalizability and external validity. None adequately adjusted for sample heterogeneity or sought to identify characteristics that may affect responses to therapy.

CONCLUSION

Failure to address prognostic or confounding variables restricts the utility of peripheral thrombolysis RCTs and helps explain why contentious debates about this therapy persist. A model for future thrombolysis trials is proposed.

Treatment of the critically ischaemic lower limb

Medical therapy of PAOD is only indicated in patients unsuitable for vascular reconstruction or angioplasty. The approach includes early detection of subjects at risk, avoidance of known risk factors, and appropriate management of diseases such as diabetes and hypertension. Vasodilators are of little use orally, though some drugs may have a part to play for short-term management and iloprost should be considered for patients unsuitable for revascularization. The ankle systolic or toe pressure should be used as a measure of disease and, if reduced, arteriography should be performed. This should not be limited to those thought fit for major surgery, as angioplasty or thrombolytic therapy may be appropriate, and aortoiliac disease may be treated by extra-anatomic bypass if not suitable for major surgery. Arterial reconstruction is associated with a reduction in both mortality and amputation, and should be attempted if a greater than 25% chance of limb salvage could be expected.

Percutaneous intraarterial thrombolysis: analysis of factors affecting outcome

PURPOSE

The authors report results of high-dose thrombolytic therapy in native arteries and vein grafts and discuss the various factors affecting outcome.

PATIENTS AND METHODS

In a retrospective study, the outcome of 82 high-dose urokinase infusions in 76 patients was examined. Comorbid risk factors as they relate to outcome were studied extensively with log-linear analysis. Positive thrombolytic outcome (PTO) is defined as complete thrombolysis of a previously occluded segment with restoration of antegrade flow augmented by angioplasty or operative intervention to clear symptoms for 30 days.

RESULTS

The procedure resulted in a PTO in 63 of 82 instances (77%). The treatment was with urokinase alone in 39 cases (47%) and urokinase followed by surgery in 34 (41%), by angioplasty in four (5%), and by angioplasty in the proximal artery and peripheral vein grafting in five (6%). All stenoses associated with grafts were treated surgically. None of the following affected thrombolytic outcome: age of occlusion, heparin dose, catheter type, length or location of graft, or artery versus graft occlusion. The 30-day mortality was 6.1%, with a procedure-related mortality rate of 2.4%. Overall amputation rate was 18% (74% for patients in whom lysis failed by 30 days).

CONCLUSION

The presence of at least one runoff vessel was the most important factor affecting outcome (PTO, 95%; P = .00001, chi 2). The most important comorbid risk factor for failed thrombolysis was coronary artery disease (P = .03, chi 2).

Thrombolysis in acute lower limb ischaemia

For the past three decades balloon embolectomy has been the treatment of choice for acute lower limb occlusion. However, although usually successful in emboli, results are often disappointing in thrombotic atherosclerotic vessels. Attempted dissolution of the clot is accordingly attractive, and has theoretically been possible since the introduction of streptokinase in 1933. This was initially used intravenously, with variable success rates, although intraarterial administration is currently the method of choice. Later thrombolytic drugs such as tissue plasminogen activator, urokinase and anistreplase have been introduced. Lysis time has also been increased by using pharmaco-mechanical methods of administration such as pulsed spray catheters, which could increase the usefulness of thrombolysis in patients with rapidly progressive neurological signs where currently surgical embolectomy would be advocated. Several newer drugs with theoretical advantages over older drugs such as single-chain urokinase-type plasminogen activator or K1K2PU are currently undergoing trials. The role of thrombolysis as an adjunct to surgical embolectomy is also promising, though again requires further trials. There is still no consensus as to which patients are best suited to thrombolysis, nor an optimum drug or method of administration. However, there seems no doubt that thrombolysis will be increasingly used in the management of peripheral limb ischaemia, though requiring a team approach between surgeons, radiologists and haematologists.

Thrombolytic therapy in the management of acute limb ischaemia

Acute limb ischaemia poses a threat to both the limb and life of a patient. Until recently, attempted revascularization by thromboembolectomy or vascular reconstruction held the best chance of limb salvage. Thrombolytic techniques afford an alternative method of management for this condition and are effective in selected patients. Low-dose intra-arterial streptokinase is the most established method of thrombolysis, although the recently developed tissue plasminogen activator offers a promising alternative. Intra-arterial thrombolysis is not an easy option, being labour intensive and requiring close co-operation between surgeon and radiologist. Thrombolytic and surgical techniques are not mutually exclusive but are best used to complement each other. Ideally patients with acute limb ischaemia should be managed by surgeons with knowledge of, and access to, optimal current surgical and non-surgical techniques.

Fibrinolytic therapy for infra-inguinal synthetic graft occlusions

The results of infra-inguinal graft fibrinolysis are variable, and the true success rates are frequently disguised by the inclusion of patients receiving adjunctive surgery, such as surgical thrombectomy, anastomosis revision and graft extension. Follow-up is sparse. As part of a larger prospective study, we have offered fibrinolysis using streptokinase to 10 patients with occluded infra-inguinal synthetic grafts. In one patient the graft could not be entered with a catheter. The remaining nine patients received local low-dose intra-arterial streptokinase. Six patients experienced complete lysis and were discharged with functioning grafts. Significant stenoses were dilated by transluminal angioplasty. The median graft patency duration was 7 months. Two patients have since required above-knee amputations. Our results using transluminal angioplasty are comparable to those results where adjunctive surgery has been used to treat underlying anastomotic stenoses. Further research into graft anastomotic stenosis management is indicated.