Louis S. McKeever

Recanalization of Chronically Occluded Aortocoronary Saphenous Vein Bypass Grafts With Long-Term, Low Dose Direct Infusion of Urokinase (ROBUST): A Serial Trial

OBJECTIVES This multicenter study sought to evaluate the short-term efficacy and safety of prolonged, low dose, direct urokinase infusion in recanalization of chronically occluded saphenous vein bypass grafts in a large sample of patients, as well as to determine the 6-month patency rates for this procedure. BACKGROUND Patients with chronically occluded aortocoronary vein grafts and uncontrolled angina pectoris have limited options for therapy. Previous work has shown that chronically occluded vein grafts can be recanalized by thrombolysis. METHODS A coaxial infusion of urokinase (100,000 U/h) was given directly into occluded vein grafts in 107 patients. Balloon angioplasty was performed after lysis was achieved. Patients were discharged with warfarin and aspirin therapy. Six-month clinical follow-up data were obtained, and repeat angiography was encouraged. RESULTS Initial patency was achieved in 74 patients (69%). Mean duration of infusion was 25.4 h, and mean urokinase dosage was 3.70 million U. Acute adverse events included acute myocardial infarction in 5 patients (5%), enzyme level elevation in 18 (17%), emergency coronary artery bypass graft surgery in 4 (4%), stroke in 3 (3%) and death in 7 (6.5%). Recanalization was unsuccessful in all seven patients who died. Six-month follow-up angiograms were obtained for 40 patients (54%), 16 of whom maintained a patent graft (40%). Angina was present in 13 patients with successful (22%) and 12 with unsuccessful (71%) recanalization at 6-month follow-up. CONCLUSIONS Chronically occluded aortocoronary vein grafts can be recanalized in approximately 70% of appropriately selected patients. Complications are similar to those observed with repeat operations. Clinical follow-up shows an improvement in angina. This procedure is intended for patients with only one occluded vein graft. Strict adherence to the protocol will improve patency and reduce complications.

Prolonged infusion of urokinase for recanalization of chronically occluded aortocoronary bypass grafts

Abstract Intravenous and intracoronary thrombolysis has been shown to be effective in lysing thrombi in the presence of acute myocardial infarction. Short-term infusion of thrombolytic agents has been used to reopen aortocoronary bypass grafts that have been recently occluded. We describe a method of open chronically occluded bypass grafts with the long-term (17 to 70 hours) low dose (50,000 to 100,000 U/hr) infusion of urokinase delivered directly to the thrombus via an infusion wire.

Acute myocardial infarction complicating recanalization of aortocoronary bypass grafts with urokinase therapy

Abstract The progressive occlusion of aortocoronary bypass grafts over time an important clinical problem. Studies have demonstrated closure rates of approximately 3% at 1 month 1 and 11 to 14% at 1 year. 2,3 Closure rates as high as 40 to 50% at 10 years are reported. 4,5 Thrombosis seems to be the major cause of occlusion in the early postoperative period. 6–8 Late graft occlusions are thought to be due to atherosclerotic esions with or without associated thrombus. The use of percutaneous angioplasty in stenotic aortocoronary bypass grafts may be successful but is of limited use in grafts with complete occlusions. Success rates are lower and the risk of distal embolization is present. Therefore, mechanical recanalization using balloon angioplasty has been avoided in these patients. 9 We have previously reported the successful recanalization of chronically occluded aortocoronary bypass grafts using a prolonged, direct infusion of urokinase. 10,11 Our clinical experience was favorable and not associated with clinically important distal embolization. We now report 3 cases of thrombolytic recanalization of occluded aortocoronary bypass grafts complicated by acute myocardial infarction, and strongly suggest that the need for continued urokinase infusion is critical in the treatment of this potential complication.

Safety of intraaortic balloon counterpulsation in patients with acute myocardial infarction receiving streptokinase intravenously

Abstract Intraaortic balloon counterpulsation (IABC) was initially described in 1968,1 and has become widely used in the treatment of patients with acute myocardial infarction (AMI),2 cardiogenic shock1,3 and in those undergoing cardiac surgery3 or percutaneous transluminal coronary angioplasty.4 The complication rate in patients treated with IABC has ranged between 25 and 36%.3,5,6 Recently, the use of thrombolytic agents has become widely accepted in the treatment of patients with AMI.7,8 A significant complication of intravenous thrombolytic therapy is bleeding, especially involving sites of access for cardiac catheterization.9 When catheterization is performed early after intravenous thrombolytic treatment, the incidence of local bleeding ranges from 18 to 43%.9 The risk of IABC soon after intravenous thrombolytic therapy has not been previously examined.

738–6 Recanalization of Chronically Occluded Bypass Grafts: The Effect of Angioplasty Site Following Extended Urokinase Infusion on 6 Month Patency

One hundred seven patients with chronically occluded aortocoronary bypass grafts were enrolled in the ROBUST trial to determine the safety and efficacy of low dose, long-term urokinase intracoronary infusions in recanalizing these vessels. Initial patency rate was 69% and 6 month patency was 47%. The relationship between site of angioplasty following successful lysis and 6 month graft patency was reviewed. Patients with angioplasty at the distal anastomosis had an 88% acute patency rate vs 85% at sites within the graft. Six month patency was 25% for distal anastomosis and 50% for intragraft sites. Although distal graft and distal anastomosis vs origin, proximal, or mid graft acute patency rates were the same (85%), 6 month patency was 32% vs 59%. Conclusion Chronically occluded vein grafts with culprit lesions in the proximal or mid graft have a greater 6 month patency rate following recanalization with long germ intragraft urokinase infusion than when the lesion is in the distal graft or anastomosis.