Two main hypotheses concerning the mechanisms responsible for coronary collateral growth suggest the involvement of chemical or mechanical factors. Since we recently demonstrated that the development of the coronary collateral circulation is not closely related to the extent or duration of myocardial ischemia, we hypothesized that chronic repeated vasodilation and increased myocardial blood flo...

To the Editor: A new medication, Aggrenox, a formulation of aspirin and extended-release dipyridamole, is being actively marketed to physicians for the treatment of patients with transient ischemic attacks and ischemic stroke. Physicians involved in pharmacological stress testing should be aware that patients taking this medicine may also be referred for pharmacological stress perfusion testing...

The effects of intracellular ribavirin on morphology and redistribution of phosphatidylserine (PS) in human erythrocytes were examined. Erythrocytes were incubated with 1 mM ribavirin in the presence/absence of dipyridamole, an inhibitor of es-type nucleoside transporter. Intracellular ribavirin was accumulated in erythrocytes with the concentration of 1361 muM, which corresponds to the blood l...

Regional myocardial blood flow before and after intravenous dipyridamole (0.56 mg/kg) was measured during cardiac catheterization in 11 patients using the 133Xe washout technique. Significant increases in heart rate (75 +/- 4 vs 87 +/- 6, p less than 0.004) and decreases in systolic blood pressure (144 +/- 8 vs 131 +/- 7, p less than 0.02) were observed with dipyridamole infusion. However, doub...

Transesophageal echocardiography allows the evaluation of proximal coronary artery anatomy and coronary blood flow velocity (CBFV). To assess the potential of transesophageal echocardiography in evaluating CBFV and its variations induced by coronary-active drugs, we studied 15 patients by high-quality pulsed wave Doppler recordings of CBFV. In these patients, transesophageal Doppler evaluation ...

OBJECTIVES This study aimed to determine the quantitative low-flow threshold for stress-induced perfusion defects with severe angina and/or significant ST-segment depression during dipyridamole hyperemia. BACKGROUND Vasodilator stress reveals differences in regional perfusion without ischemia in most patients. However, in patients with a perfusion defect, angina, and/or significant ST-segment...

We investigated the potential of aspirin and dipyridamole in combination to inhibit thrombus formation by comparing endarterectomized segments of 20 dog carotid arteries in animals treated with pre- and post-operative aspirin and dipyridamole to 20 arteries from untreated animals and 20 arteries from animals receiving intra-operative heparin. The temporal profile of thrombus formation was asses...

Dipyridamole, an inhibitor of facilitated transport systems for purines and pyrimidines, was shown to enhance the toxicity of methotrexate (MTX) against cells in culture and in mice. Under certain incubation conditions, the availability of preformed pu rines and pyrimidines in undialyzed serum appeared to render Chinese hamster ovary cells insensitive to MTX. Addition to the culture of nontoxic...

Background. We wished to assess whether dipyridamole echocardiography test (DET) can detect jeopardized myocardium after thrombolytic therapy. Methods and Results. Seventy-six consecutive patients with a first acute myocardial infarction (AMI) were treated with 2 million IU urokinase i.v. within 4 hours of the onset of AMI and underwent high-dose (as much as 0.84 mg/kg over 10 minutes) DET 8-10...