Prolonged selective urokinase infusion in totally occluded coronary arteries and bypass grafts: two case reports

Long-term angiographic follow-up of occluded saphenous bypass grafts treated with prolonged urokinase infusion

We report on 10 occluded saphenous vein bypass grafts in nine patients treated with prolonged urokinase infusion. Our purpose was to evaluate the patency of these grafts during long-term follow-up. We retrospectively analyzed consecutive patients treated at a single center. All patients had angiography 0.25 to 54 months after treatment. Results indicated that clot lysis was achieved in all grafts with urokinase infusions of 1,790,000 to 25,920,000 units given over 17 to 108 hours. In two grafts there was no filling of the distal native vessel and in one, a 50% stenosis with ulceration remained. There was a progressive loss of graft patency over the first 18 months, but 50% of the grafts that were opened with prolonged urokinase infusion remain patent. Long-term patency depends upon successful opening without residual obstruction and with good flow into the distal native vessel.

Coronary thrombus: a novel catheter-based approach to treatment

The presence of coronary thrombus during intracoronary interventions increases the risk of complications during the procedure. We describe a novel approach to infusing thrombolytic agents selectively into a coronary artery utilizing a new low-profile perfusion balloon. This approach may add a useful new treatment for resistant intracoronary thrombi.

Treatment of acute myocardial infarction with prolonged intracoronary urokinase delivery through intracoronary infusion catheter

Severe acute myocardial infarction in young patients is plagued by high mortality. We report the case of a 25-year-old man, with a family history of ischemic heart disease, who was treated with acute and prolonged intracoronary urokinase infused through a miniaturized catheter engaged in a large thrombus occluding the left anterior descending artery. Rapid and stable recanalization was achieved with complete lysis of thrombotic material.

New treatment approach for chronic total occlusions of saphenous vein grafts: thrombolysis and intravascular stents

Balloon dilation of saphenous vein graft (SVG) occlusions has a lower success rate than angioplasty of native coronary arteries. To improve this outcome, a new therapy for chronic total SVG occlusions was developed. In three aortocoronary bypass graft patients with class III-IV angina and chronic occlusion of the SVGs to the left anterior descending artery (age of occlusions: 2-24 wk, age of graft 1-13 yr), standard recanalization was achieved with a guide wire and intracoronary urokinase infusion (0.5-1.0 million unit bolus followed by 100,000 IU/hr for 11-24 hr; mean infusion time: 19.7 hr). In each patient, a residual focal stenosis (average 82.5%) was successfully dilated and stented (single 4.0 mm Palmaz-Schatz in two patients and a 3.5 mm Strecker stent in the other). All patients had complete relief of symptoms and no sequelae. During a mean 7.7 mon follow-up, 6-mon arteriographic evaluation in two patients showed minimal intra-stent narrowing (26% and 34%). In the Strecker stent patient, the device proved too small for the vein graft, leading to an 89% stent stenosis found on follow-up arteriography at 5 mon. The stent was redilated successfully with a 5% residual narrowing. After urokinase recanalization of chronic total SVG occlusions, intravascular stents may improve the long-term results seen with conventional SVG angioplasty.

Acute myocardial infarction complicating urokinase infusion for total saphenous vein graft occlusion

Saphenous vein graft occlusions have been successfully treated with extended urokinase infusions. We report a case of myocardial infarction complicating this treatment. A review of reported cases suggests that this complication may not be uncommon. The optional drug, dose, and infusion technique for intra-graft lytic therapy has not been determined. The costs, risks, and difficulty of this technique may limit its application.

Prolonged intravenous urokinase infusion: an alternative pharmacologic approach in the treatment of thrombus-containing saphenous vein graft stenoses

A subtotally occlusive saphenous vein graft stenosis resolved after rapid intracoronary and prolonged intravenous urokinase infusion. Additional therapy was unnecessary, avoiding the attendant risks of saphenous vein graft angioplasty. Combined intracoronary and intravenous urokinase infusion should be considered prior to coronary angioplasty of saphenous vein graft stenoses, particularly when diffuse degeneration is present or the risk of underlying thrombus is high.

Successful angioplasty of a chronically occluded saphenous vein graft using a prolonged urokinase infusion from the brachial route

A 68-year-old man who presented with unstable angina had had cardiac bypass surgery 12 years earlier and successful angioplasty of a native circumflex lesion 18 months previously. Repeat catheterization showed a widely patent angioplasty site but interval closure of a saphenous vein graft to a large marginal branch that was totally occluded proximally. A stress test revealed significant myocardial ischemia. Severe peripheral peripheral vascular disease with known bilateral iliac artery occlusions mandated a brachial approach. Because of his high risk for repeat cardiac surgery, it was elected to attempt saphenous graft angioplasty following a prolonged urokinase infusion. After an infusion of urokinase for 36 hr, antegrade flow was restored and angioplasty was carried out successfully on a discrete mid-graft legion. Subsequent stress testing showed resolution of the ischemia. There were no vascular complications.

Acute complications of percutaneous transluminal coronary angioplasty for total occlusion

The incidence of major complications after percutaneous coronary angioplasty (PTCA) of a totally occluded artery was assessed retrospectively. A total of 1649 PTCA procedures were analyzed. After exclusion of procedures for acute myocardial infarction or total occlusion that resulted from restenosis, 90 patients were selected. Forty-four patients (49%) had stable angina and 46 (51%) had unstable angina. The estimated duration of occlusion was 87 +/- 78 days in patients with stable angina, as compared with 10 +/- 8 days in patients with unstable angina (p less than 0.001). Abrupt vessel closure during PTCA occurred only in patients with unstable angina (0% versus 17%, p less than 0.05). The major complication rate was 2.5% in the stable angina group, and 20% in unstable angina group (p less than 0.01). This rate was also significantly higher than the complication rate of 8% observed in 442 procedures that were performed during the same period in patients with the unstable angina and nonocclusive stenosis (p less than 0.01). Patients with unstable angina who undergo PTCA of a totally occluded artery represent a subset of high risk for major complications.

Mechanism of acute myocardial infarction in patients with prior coronary artery bypass grafting and therapeutic implications

Although acute myocardial infarction (AMI) is usually due to thrombotic occlusion when involving a native coronary artery, the mechanism responsible for AMI in patients with previous coronary artery bypass grafting (CABG) is not well understood. Since knowledge of pathophysiology of AMI may alter subsequent management, angiograms obtained between 1 hour and 7 days of AMI (median 1 day) were reviewed in 50 patients greater than 1 year after CABG. The culprit vessel was identified by the presence of residual stenosis and/or thrombus in the vessel supplying the infarct zone or by reviewing previous angiograms. The infarct vessel was identified as a vein graft in 38 (76%) patients, the native vessel in 8 patients (16%) and could not be accurately determined in 4 patients (8%). Among the 38 vein grafts suspected as the infarct vessel, unequivocal angiographic evidence of residual thrombus (filling defect/persistent staining) was present in 31 (82%) and was greater than 2 cm in length in 15 patients. Successful reperfusion occurred in only 2 of 8 (25%) grafts after intravenous thrombolytic therapy. Intragraft thrombolysis with or without additional angioplasty was successful at restoring flow in 8 of 10 (80%) grafts. Data indicate that in patients who have undergone previous CABG, AMI is usually caused by thrombotic occlusion of a saphenous vein graft and that conventional intravenous thrombolytic therapy may be inadequate to restore flow. The large mass of thrombus and absent flow in the graft may require subselective drug infusion, a higher thrombolytic dose or a mechanical means of recanalization.

Intracoronary thrombectomy: a new approach to total occlusion

After initial failure with conventional angioplasty of a total right coronary artery occlusion, we were successful in obtaining patency using a combination of intracoronary thrombectomy and thrombolysis. This represents the first report of this technique in the therapy of total right coronary occlusions.

A complication of prolonged urokinase infusion into a chronically occluded aortocoronary saphenous vein graft

Recanalization of a chronically occluded aortocoronary saphenous vein graft was performed, using a prolonged intracoronary infusion of urokinase followed by percutaneous transluminal coronary angioplasty (PTCA). Despite an angiographically successful result, the patient developed acute myocardial infarction, presumably secondary to distal migration of partially lysed thrombus. One week after successful angioplasty, the graft was once again proximally occluded.