A randomized trial of low osmolar ionic versus nonionic contrast media in patients with myocardial infarction or unstable angina undergoing percutaneous transluminal coronary angioplasty.

OBJECTIVES: The purpose of this study was to determine prospectively whether the differences in anticoagulant and antiplatelet effects of ionic and nonionic contrast media after angiographic or clinical outcomes in patients with unstable ischemic syndromes undergoing percutaneous transluminal coronary angioplasty. BACKGROUND: The interaction of platelets and thrombin with the endothelium of injured vessels contributes to thrombosis and restenosis after coronary angioplasty. Case reports and retrospective observations have reported an increased risk of thrombosis with the use of nonionic contrast media. METHODS: A total of 211 patients with acute myocardial infarction or unstable angina undergoing coronary angioplasty were randomized to receive nonionic or ionic low osmolar contrast media. Coronary angiograms were assessed by a technician blinded to the study contrast media, and clinical events were monitored by an independent nurse for 1 month. RESULTS: Patients receiving the ionic media were significantly less likely to experience decreased blood flow during the procedure (8.1% vs. 17.8%, p = 0.04). After the angioplasty, residual stenosis, vessel patency, the incidence of moderate to large thrombi and use of adjunctive thrombolytic therapy were similar between the two groups. However, patients receiving ionic media had fewer recurrent ischemic events requiring repeat catheterization (3.0% vs. 11.4%, p = 0.02) and repeat angioplasty during the initial hospital stay (1.0% vs. 5.8%, p = 0.06). One month after angioplasty, patients receiving ionic contrast media reported significantly fewer symptoms of any angina (8.5 vs. 20.0%, p = 0.04) or of angina at rest (1.4% vs. 11.8%, p = 0.01) and a reduced need for subsequent bypass surgery (0% vs. 5.9%, p = 0.04), compared with patients receiving the nonionic media. CONCLUSIONS: These findings demonstrate that in patients with unstable ischemic syndromes undergoing coronary angioplasty, the use of ionic low osmolar contrast media reduces the risk of ischemic complications acutely and at 1 month after the procedure. Therefore, low osmolar ionic contrast media should be strongly considered when performing interventions in patients with unstable angina or myocardial infarction.

Prospective, randomized trial of prolonged intracoronary urokinase infusion for chronic total occlusions in native coronary arteries.

OBJECTIVES: The purpose of this study was to determine the safety and efficacy of three dosing regimens of intracoronary urokinase for facilitated angioplasty of chronic total native coronary artery occlusions. BACKGROUND: Percutaneous transluminal coronary angioplasty of chronically occluded (>3 months) native coronary arteries is associated with low initial success secondary to an inability to pass the guide wire beyond the occlusion. METHODS: Patients were enrolled if a chronic total occlusion >3 months old could not be crossed with standard angioplasty equipment. Of the 101 patients enrolled, 41 had successful guide wire passage and were excluded from urokinase treatment. The remaining 60 patients were randomized to receive one of three intracoronary dosing regimens of urokinase over 8 h (group A = 0.8 million U; group B = 1.6 million U; group C = 3.2 million U), and angioplasty was again attempted after completion of the urokinase infusion in 58 patients. RESULTS: Coronary angioplasty was successful in 32 patients (53%) (group A 52%, group B 50%, group C 59%, p = 0.86). This study had a 90% power to detect at least a 50% difference between dosing groups at alpha 0.05. Bleeding complications requiring blood transfusion did not differ significantly among the dosing groups (A 0%, B 15%, C 6%, p = 0.14), although major bleeding episodes were less common in group A (p < 0.05). There were no major procedural or in-hospital complications. Angiographic follow-up in 69% of the patients with successful angioplasty revealed target vessel patency in 91% but an angiographic restenosis rate of 59%. CONCLUSIONS: A prolonged supraselective intracoronary infusion of urokinase can be safely administered and may facilitate angioplasty of chronic total occlusions. Lower doses of urokinase are equally effective and result in fewer bleeding complications than do higher dosage regimens. Vessel patency is frequently maintained, but restenosis remains a problem.

Prolonged urokinase infusion for chronic total native coronary occlusions: clinical, angiographic, and treatment observations.

Prolonged intravascular infusion of urokinase has proven beneficial in reestablishing patency of chronically occluded peripheral arteries and saphenous vein grafts. This study was performed to assess the efficacy and safety of prolonged urokinase infusion as a prelude to angioplasty in chronically occluded native coronary arteries, that had failed standard angioplasty techniques. Twenty-five patients with objective evidence for ischemia in the distribution of a chronic coronary occlusion were referred for percutaneous intervention. Patients were assessed for any potential exclusions from lytic therapy. Urokinase infusion through both a SOS wire and a stable guiding catheter was continued at 100,000-240,000 units/hr for 8-25 hr; patients then underwent attempted balloon angioplasty. Mean duration of urokinase infusion was 20.6 +/- 7.7 hr (total dose 163,000 +/- 52,447 units/hr). Fibrinogen levels dropped slightly with this (300 +/- 129 to 203 +/- 81 mg/dl, P = 0.02). Angiography posturokinase showed improvement in 7 (28%) with regard to coronary flow (> or = 1 TIMI-grade). Angioplasty was successful in 13 (52%), with final angiographic result revealing thrombus in 5 (20%), or dissection 8 (32%). The infusions were well-tolerated with a low incidence of chest pain, 2 (8%) or ischemic ECG response, 2 (8%); myocardial infarction, 2 (8%); or significant bleeding 2 (8%). All patients survived the procedure, with a length-of-hospital stay = 5.1 +/- 4 days. Use of prolonged preangioplasty intracoronary urokinase infusion can be done safely with success in roughly one-half of patients with chronic total native coronary occlusions who have failed prior attempts at percutaneous intervention.(ABSTRACT TRUNCATED AT 250 WORDS)

Determination of the mutations responsible for the Lesch-Nyhan syndrome in 17 subjects.

Hypoxanthine--guanine phosphoribosyltransferase (HPRT) is a purine salvage enzyme that catalyzes the conversion of hypoxanthine to inosine monophosphate and guanine to guanosine monophosphate. Previous studies of mutant HPRT proteins analyzed at the molecular level have shown a significant heterogeneity. This investigation further verifies this heterogeneity and identifies insertions, deletions, and point mutations. The direct sequencing of the polymerase chain reaction-amplified product of reverse-transcribed HPRT mRNA enabled the rapid identification of the mutations found in 17 previously uncharacterized cell lines derived from patients with the Lesch-Nyhan syndrome.