Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “DIPYRIDAMOLE”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 487 records · Page 27Linked to original sources
PubMed1982

Effect of dipyridamole and prostacyclin on rabbit platelet adherence in vitro and in vivo.

The adherence of 51Cr-labeled platelets to the subendothelium of rabbit aortas was inhibited in vitro and in vivo by high concentrations of dipyridamole (100 microM in vitro, 2.5 or 12.5 mg/kg in vivo). Dipyridamole (100 microM) inhibited release of 14C-serotonin from platelets that adhered to the subendothelium or to a collagen-coated glass surface; lower concentrations of dipyridamole had only a slight inhibitory effect. Scanning electron microscopy showed that many of the platelets that adhered to the subendothelium were rounded, with few pseudopodia. The combination of dipyridamole with PGI2 was no more inhibitory of platelet adherence than either agent alone; however, this combination of inhibitors exerted synergistic inhibitory effects on aggregation and release of 14C-serotonin from platelets aggregated by collagen. The effects of dipyridamole on platelet adherence are a consequence of the action of dipyridamole alone and do not appear to result from its interaction with PGI2 formed by injured vessels in vivo, since the inhibitory effect is not influenced by aspirin inhibition of PGI2 formation, either at the shear rates in the in vitro studies or under the shear conditions found in rabbit aortas in vivo.

Animals↗
PubMed1981

The effect of low-dose aspirin and dipyridamole upon atherosclerosis in the rabbit.

To examine the effect of antiplatelet therapy upon atherosclerosis in an animal model, aspirin and dipyridamole were administered to female New Zealand rabbits while they were fed a 2% cholesterol diet. Four experimental groups of 15 animals were established: Group I (Control), no medication; Group II, aspirin, 40 mg orally five days a week; Group III, dipyridamole, 25 mg orally five days a week; Group IV, aspirin and dipyridamole. After seven weeks, the animals were sacrificed and their aortas were removed and stained. Group means of the percentage of total aortic lumenal surface occupied by gross atheromata were calculated and statistically compared with the control group mean: Group I - 49%, Group II 36%, p = NS, Group III - 47%, Group IV - 25%, p less than .01. Histologic sections of each aorta confirmed the stained areas to be atheromata of varying complexity. The lesions in animals treated with dipyridamole alone exhibited a distinct increase in smooth muscle cell proliferation. For animals receiving a combination of aspirin and dipyridamole the lesions were smaller and less advanced than those in the control group. These findings indicate that experimental atherosclerosis in rabbits is modified by the administration of anti-platelet agents and that atheroma formation is significantly inhibited when aspirin and dipyridamole are given in combination.

Animals↗
PubMed1995

Differences in vasodilatory response to dipyridamole between patients with angina and normal coronary arteries and patients with successful coronary angioplasty.

BACKGROUND: Previous studies reported a reduced coronary blood flow reserve, assessed by the intravenous administration of dipyridamole, in patients with angina and normal coronary arteries, and early after successful coronary angioplasty, which suggests the presence of small coronary vessel dysfunction. This study aimed to establish whether the mechanisms of small coronary vessel disease in these two groups of patients are similar. METHODS: The effects of the intracoronary infusion of adenosine and dipyridamole (maximum dose 2.7 and 7.5 mg/min, respectively) on coronary blood flow velocity were assessed in 11 patients with angina and normal coronary arteries (group A) and in 12 patients immediately after successful coronary angioplasty (group B) using a 0.018" Doppler wire. RESULTS: Baseline coronary blood flow velocity was significantly higher in group B than group A (34 +/- 14 versus 19 +/- 8 cm/s; P = 0.001). In group A, coronary blood flow velocity was higher during adenosine than dipyridamole infusion (74 +/- 17 versus 58 +/- 21 cm/s; P < 0.001), whereas in group B velocities were similar (85 +/- 30 versus 78 +/- 32 cm/s; NS). CONCLUSIONS: In patients with angina and normal coronary arteries, a maximal dose of adenosine causes a greater coronary dilation than that of dipyridamole. Given that dipyridamole operates mainly through an inhibition of adenosine re-uptake, it can only dilate the arteriolar segments exposed to endogenous adenosine. Therefore, the lower response to dipyridamole than to exogenous adenosine observed in patients with angina and normal coronary arteries suggests an impairment of the pre-arterioles that are not influenced by endogenous adenosine, resulting in a limited flow-mediated dilation in response to arteriolar dilation. Such an impairment is not apparent immediately after successful coronary angioplasty, where the most obvious abnormality is an increase of baseline coronary blood flow velocity.

Adenosine↗
PubMed1994

Hemodynamic changes during dipyridamole stress in patients with aortic stenosis.

Dipyridamole is a potent vasodilator used in pharmacologic stress testing. Patients with severe aortic stenosis are not suitable for exercise, and are usually not subjected to testing with vasodilator substances. The aim of the present study was to investigate hemodynamic changes during dipyridamole stress test in patients with aortic stenosis and to see if these changes where reversible by theophylline, an aminophylline derivative. Ten patients with aortic stenosis underwent right and left heart catheterization. Simultaneous recordings of cardiac output, left ventricular and aortic pressures were performed at baseline, after intravenous dipyridamole infusion (0.56 mg/kg dissolved in 250 ml of saline given over four minutes), and after intravenous theophylline injection (115 mg). There was an increase in heart rate, stroke volume and flow, and a decrease in systolic and diastolic blood pressure and in systemic vascular resistance after dipyridamole infusion. Left ventricular stroke work index and pressure time per minute increased after dipyridamole infusion suggesting an increase in myocardial oxygen demand, but there was no significant change compared to baseline after theophylline administration. Less than one third of left ventricular work was due to the resistance of the aortic valve. The aortic valve area changed with changes in flow. It is concluded that cardiac output, left ventricular work and myocardial oxygen demand after dipyridamole infusion increased in patients with aortic stenosis. The systemic vascular resistance seems to be more important determinant of cardiac output than the aortic valve obstruction. The calculated valve area appears to be flow-dependent.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1994

Dipyridamole angina: a specific symptom of severe multivessel disease.

BACKGROUND: Several studies have indicated that ischemia induced by dipyridamole is frequently associated with angina or ischemic ST-segment depression and that it occurs mainly in patients with three-vessel disease, those with collateral vessels, or those with both. METHODS: In order to analyze the diagnostic relationships among them, we studied 227 consecutive patients who underwent coronary angiography and dipyridamole-thallium scintigraphy. RESULTS: A perfusion defect was found in 134 patients. Of these, 88 patients (66%) showed no significant ECG modifications or angina; 46 (34%) had a transient ST-segment depression, which was associated with typical angina ('dipyridamole angina') in 12. These 12 patients had three-vessel disease with intercoronary collateral circulation. Among the 134 patients with coronary critical stenoses and a positive thallium-dipyridamole test, collateral vessels were detected in 91 (68%). CONCLUSION: Dipyridamole angina, occurring during a positive dipyridamole-thallium test, is usually a manifestation of severe coronary stenoses with collateral circulation. However, as a diagnostic symptom it is characterized by high specificity but low sensitivity.

Aged↗
PubMed1994

[Differences between women and men in the dipyridamole test. Symptomatic and electrocardiography findings in patients with coronary heart disease].

BACKGROUND: Problems are often encountered in evaluating the exercise stress ECG in women due to frequent false pathological findings. Besides the exercise ECG in the noninvasive diagnosis of coronary heart disease (CHD), the dipyridamole test is often used. As yet little is known about, whether a similarly high incidence of false positive test results occur under provocation with dipyridamole in women as in the exercise stress ECG. PATIENTS: In the present study the results of the dipyridamole test and of the coronary angiography in 218 patients, diagnosed as suspected of having CHD, were compared, especially allowing for specific sex differences. RESULTS: The prevalence of CHD in women was 17.8% and 56.1% in men. Under provocation with dipyridamole allowing for the indicator angina pectoris, the incidence of a false positive test results in relation to a significant coronary stenosis is higher in women with 80.5% than in men with 36.4% (p < 0.001). By contrast, men have a significantly higher rate of false negative test findings (40.9% to 11.1%; p < 0.001). Whereas the women obtained a sensitivity of 87.5%, the rating for men was 70.1%. Specificity was 21.6% for women and 48.7% for men. Test efficiency for men was 60.7% whereas for women 33.3% were calculated. The reaction of heart rate (significant increase of 33%) and systolic and diastolic blood pressure (no significant changes) did not reveal any relevant differences between men and women during the dipyridamole test. CONCLUSION: For patients with CHD similar diagnostic uncertainties occurred relating to specific sex differences in the results of the dipyridamole test, just like those known from the exercise ECG.

Adult↗
PubMed1994

The enhancement of the frequency of resistance to N-phosphonoacetyl-L-aspartate and methotrexate by 1-beta-D-arabinofuranosylcytosine: the effect of dipyridamole.

In cultured cells, dipyridamole, in a dose-dependent manner, prevented the enhancement by 1-beta-D-arabinofuranosylcytosine (AraC) of either N-phosphonoacetyl-L-aspartate (PALA)- or methotrexate- resistance frequency. Maximal blockade of enhancement of PALA-resistance frequency occurred if the dipyridamole was added with or within about 20 hr of PALA addition. Thereafter, the effect of dipyridamole decreased. Nitrobenzylthioinosine similarly reduced AraC enhancement of PALA- and methotrexate-resistance frequency. Both dipyridamole and nitrobenzylthioinosine inhibited uridine and thymidine uptake into cells to a similar extent in cells pretreated or not with AraC. Thus, although inhibition of nucleoside uptake would seem a reasonable explanation for the effect on PALA-resistance frequency by dipyridamole, there is no obvious explanation at present of how dipyridamole selectively affects resistance frequency in AraC-pretreated cells.

Animals↗
PubMedDate not supplied

[Diagnosis of ischemic heart disease by dipyridamole-stress two-dimensional echocardiography].

The diagnostic usefulness of dipyridamole-stress two-dimensional echocardiography was assessed in 82 patients consisting of 27 patients with angina pectoris, 42 with myocardial infarction, and 13 control subjects. Two-dimensional echocardiographic monitoring was performed during dipyridamole infusion: 0.56 mg/kg for 4 minutes, then discontinuation for 4 minutes, followed by a final infusion of 0.28 mg/kg for 2 minutes. The cumulative dose was 0.84 mg/kg. Worsening or fixed wall motion abnormality with unaffected baseline indicated a positive finding. All patients underwent coronary angiography. The sensitivity and specificity of dipyridamole-stress two-dimensional echocardiography for diagnosis of significant coronary artery stenosis (> or = 75%) were 84% (58/69) and 92% (12/13), respectively. The sensitivity of this method for the branches of the coronary artery was 85% for the left anterior descending artery, 80% for the right coronary artery, and 75% for the left circumflex artery. The sensitivity for single-, double-, triple-vessel disease was 75%, 81% and 100%, respectively. The sensitivity and specificity of the dipyridamole electrocardiogram (ST depression more than 0.1 mV) were 33% (23/69) and 77% (10/13), respectively. The appearance of dipyridamole-stress induced wall motion abnormality was significantly earlier than those of chest pain and ST segment depression. Side effects were observed in 43% (35/82) of patients, but were only mild and transient. Dipyridamole-stress two-dimensional echocardiography is the best method for detecting coronary artery stenosis and predicting the localization of lesion sites.

Aged↗
PubMed1994

Effects of antiplatelet therapy with indobufen or aspirin-dipyridamole on graft patency one year after coronary artery bypass grafting.

Saphenous vein coronary artery bypass graft patency can be increased by antiplatelet therapy. Aspirin plus dipyridamole are effective but are associated with tolerability problems. Indobufen is a possible alternative antiplatelet agent that may be better tolerated. A prospective, randomized, double-blind, parallel-group study was undertaken to compare the efficacy and safety of indobufen 200 mg twice daily with aspirin 300 mg thrice daily plus dipyridamole 75 mg thrice daily in preventing occlusion of autologous saphenous vein coronary artery bypass grafts. A total of 803 patients were randomized in the study, of whom 552 had a follow-up coronary angiogram approximately 1 year after operation. All anastomoses were patent in 56% of indobufen-treated patients and 59% of aspirin-dipyridamole recipients (p = 0.384). The percentage of all anastomoses patent was 82% in the indobufen group and 83% in the aspirin-dipyridamole group (p = 0.297). Mean postoperative blood loss was significantly less in the indobufen group (p = 0.043). Patients who received indobufen also had significantly fewer adverse events considered to be treatment-related compared with aspirin-dipyridamole recipients (p = 0.02). At the doses tested indobufen was as effective as aspirin plus dipyridamole in preventing occlusion of saphenous vein grafts and was better tolerated. Because indobufen was associated with less postoperative blood loss it may be used before operation in coronary artery bypass grafting.

Adolescent↗
PubMed1993

Overcoming of vincristine resistance in HL-60 human promyelocytic leukemia cell line by dipyridamole.

Dipyridamole enhanced the anti-cancer activity of VCR toward both wild type HL-60 and VCR-resistant subline, HL-60/R, which had a 15 fold greater resistance to VCR as compared with the wild type cell line. The resistance to VCR of HL-60/R cells was associated with a marked decrease in the intracellular VCR accumulation. After incubation with VCR for 24 hrs, 0.61 and 0.24 pmol VCR per one million cells were accumulated in the wild and the resistant cells, respectively. Dipyridamole dose-dependently increased the intracellular VCR accumulation in the wild type cells and also it restored the intracellular VCR accumulation in the VCR-resistant cells. Addition of 10 microM dipyridamole to the culture medium enhanced the intracellular accumulation of VCR during 24 hr incubation by 2.6 fold and 6.0 fold in HL-60 and HL-60/R cells, respectively. The VCR-resistance in HL-60/R cells was able to be overcome by the addition of 2.5 microM dipyridamole to the culture medium. This concentration of dipyridamole could be obtained by the intravenous administration without severe adverse effects. These results indicate that dipyridamole should be effective in the treatment of patients with hematologic malignancy resistant to VCR.

Dipyridamole↗
PubMed1993

Mechanism of the discrepant effect of a combination of methotrexate plus dipyridamole on human hematologic cell lines.

Mechanisms of the discrepant effect of methotrexate and dipyridamole on human hematologic cultured cell lines were investigated by analyzing intracellular methotrexate levels and thymidine incorporation through the salvage pathway, since the combination of methotrexate and dipyridamole has different effects according to cell type: additive effects on ML-1 and THP-1 (myelo-monocytoid cells); reduced effects on MOLT-3, SKW-3, P32/ish and BL-TH (lymphoid cells). Dipyridamole reduced the toxicity of methotrexate by diminishing intracellular methotrexate levels in MOLT-3 and BL-TH (lymphoid cells), in which the reduction of intracellular methotrexate affected more than just the blocking of the salvage pathway required for growth by dipyridamole. On the other hand, dipyridamole enhanced the toxicity of the combination by blocking the salvage pathway in an ML-1 (myelo-monocytoid cell) and in a methotrexate-resistant subline of BL-TH/MTX (lymphoid cell), in which the salvage pathways were considered activated. Dipyridamole could prove to be a useful drug for reversing the drug resistance caused by the activation of the salvage pathway.

Adult↗
PubMed1977

The effect of dipyridamole on the thrombocyte count and bleeding tendency in open-heart surgery.

The effect of dipyridamole (Persantine) on the thrombocyte count and bleeding tendency in connection with open-heart surgery and perfusion was studied in 22 patients. A control series of 21 patients undergoing open-heart surgery was available. The treatment group received dipyridamole, 0.5 mg. per kilogram of body weight, in the beginning of cardiopulmonary bypass into the heart-lung machine and thereafter 10 mg. intravenously three times daily for 2 days. From the third day dipyridamole was administered by mouth, 75 mg. three times a day, until the patient was discharged from hospital. We found that dipyridamole had the effect of maintaining the thrombocyte count during cardiopulmonary bypass and the first and second postoperative days. Thereafter no significant difference was seen between the dipyridamole and control groups. The use of dipyridamole did not increase the postoperative hemorrhagic tendency. There were no significant differences in per- and postoperative blood loss and in bleeding and activated partial thromboplastin times between the groups.

Adolescent↗
PubMed2003

Glibenclamide blunts coronary flow reserve induced by adenosine and dipyridamole.

OBJECTIVE: A reduced coronary flow reserve is considered indicative of significant coronary stenosis. As experimental data suggest that adenosine and dipyridamole induce vasodilatation by opening of ATP-sensitive potassium channels, we sought to determine the effect of glibenclamide, an antidiabetic blocker of ATP-sensitive potassium channels, on adenosine- and dipyridamole-induced coronary flow reserve. DESIGN: Coronary flow velocities were measured in 15 pigs using a Doppler flow wire. The effect of increasing glibenclamide concentrations (0.1-10 microM) on adenosine-induced coronary flow reserve was examined in five animals. Ten pigs served as time controls. The time controls were subsequently treated by 3 microM glibenclamide (n = 5) or corresponding vehicle (n = 5) and the flow response to 0.56 mg/kg dipyridamole determined. RESULTS: Glibenclamide elicited a concentration-dependent inhibition of adenosine-induced coronary flow reserve, reaching significance at glibenclamide concentrations of 3 and 10 microM. The coronary flow reserve stimulated by dipyridamole was reduced significantly by 3 microM glibenclamide. CONCLUSION: Glibenclamide blunts coronary flow reserve stimulated by adenosine and dipyridamole. This interaction may have clinical implications in diabetics undergoing adenosine- or dipyridamole-dependent diagnostic procedures.

Adenosine↗
PubMed1999

Dipyridamole TI-201 SPECT imaging in patients with myocardial bridging

PURPOSE: Exercise-induced myocardial perfusion abnormalities have been reported in patients with myocardial bridging, possibly by tachycardia-induced shortening of diastole. Dipyridamole TI-201 SPECT findings were evaluated in patients with myocardial bridging to assess perfusion abnormalities during dipyridamole stress. MATERIALS AND METHODS: Dipyridamole TI-201 SPECT images of 12 patients with myocardial bridging (> or = 50% systolic narrowing) were evaluated. The peak heart rate during dipyridamole stress was less than 110 beats/min in all patients. The control group was 118 patients with fixed left anterior descending artery (LAD) disease. RESULTS: Fourteen sites of systolic arterial narrowing were present in LAD: two in mid-LAD, seven in distal LAD, and five in septal branches. Dipyridamole TI-201 SPECT showed reversible perfusion defects in three of six sites with 50% to 70% systolic narrowing and seven of eight sites with more than 80% systolic narrowing. Overall, 71% (10 of 14) had a reversible perfusion defect. Five patients with septal branch compression had a perfusion defect in the midanteroseptal wall without an apical abnormality. In the control group, no patient had an isolated perfusion defect in the midanteroseptal wall or septal branch disease (5 of 12 compared with 0 of 118; P < 0.001). CONCLUSIONS: Perfusion abnormalities on dipyridamole TI-201 SPECT are observed in LAD or its branches in patients with high-grade myocardial bridging. Myocardial bridging may decrease coronary flow reserve but not necessarily via tachycardia. Isolated perfusion defects in the midanteroseptal wall may be a characteristic finding of septal branch compression, because a fixed lesion involving a septal branch only is rare.

Journal Article↗
PubMed2005

Efficacy of aspirin plus extended-release dipyridamole in preventing recurrent stroke in high-risk populations.

OBJECTIVE: To assess the efficacy of aspirin plus extended-release dipyridamole compared with aspirin alone for the prevention of recurrent stroke among high-risk groups. DESIGN: A post hoc analysis was conducted using data from the European Stroke Prevention Study 2. Rates of annual strokes and vascular events were determined for the aspirin plus extended-release dipyridamole group (n = 1650) and the aspirin-only group (n = 1649), and were stratified by risk subgroup and univariate risk factors. Stroke models from the Framingham Study and the Stroke Prognostic Instrument II were applied to subjects in the European Stroke Prevention Study 2 to categorize patients into risk groups. RESULTS: Compared with aspirin alone, aspirin plus extended-release dipyridamole demonstrated a more pronounced efficacy in reducing the risk for stroke and vascular events among patients younger than 70 years; those with hypertension, prior stroke, or transient ischemic attack; current smokers; and those with any prior cardiovascular disease. Relative hazard reductions favored the combination of aspirin plus extended-release dipyridamole, and were greatest for the high-risk Framingham Study group and the moderate-risk Stroke Prognostic Instrument II subgroup. CONCLUSION: Aspirin plus extended-release dipyridamole is more effective than aspirin alone at preventing stroke, and the difference in efficacy increases in higher-risk patients.

Adult↗
PubMed1990

Cardiac risk in vascular surgery. The oral dipyridamole-thallium stress test.

The value of the oral dipyridamole-thallium stress test in identifying patients at high risk of myocardial infarction after vascular procedures has not been documented. We studied prospectively 46 patients who underwent an oral dipyridamole-thallium stress test before undergoing vascular operations. Twenty patients (43%) had a positive test result, defined by a thallium defect with reperfusion, while 26 patients had a negative test result. Myocardial infarctions were documented postoperatively in 5 (25%) of 20 of the group with positive results and 1 (4%) of 26 of the group with negative results. Three of the six myocardial infarctions were clinical; all three were in the group with positive results. No correlation was identified between dipyridamole-thallium stress test results and clinical cardiac history. A positive dipyridamole-thallium stress test result is a more sensitive predictor of postoperative myocardial infarction than ejection fraction or history of coronary artery disease. The oral dipyridamole-thallium stress test is as useful as the intravenous test in this setting.

Administration, Oral↗
PubMed2001

Performance of a polyurethane vascular prosthesis carrying a dipyridamole (Persantin) coating on its lumenal surface.

A porous polyurethane vascular prosthesis with an internal diameter of 5 mm was studied. The graft carries a coating of immobilized dipyridamole (Persantin(R)) on the surface of its lumen. Dipyridamole is a potent nontoxic inhibitor of platelet activation/aggregation, and also a strong inhibitor of vascular smooth muscle cell proliferation. The polyurethane material is also known as Chronoflex(R), and already finds use as a vascular access graft. The coated vascular graft was studied in vitro (hemocompatibility, interaction with blood platelets and cultured endothelial cells), as well as in two established in vivo models. In the first in vivo study, coated grafts were implanted in goats, as a bypass of the carotid artery (four animals, eight grafts, length of the graft was approximately 12 cm). Four uncoated grafts were used as controls in otherwise identical experiments. In the second in vivo experiment, eight sheep were used. Each animal received one coated and one uncoated prosthesis as an interposition graft in the carotid artery (length of the graft was 4 cm). The in vitro experiments revealed that the dipyridamole coating has three beneficial effects: reduced thrombogenicity, reduced adherence of blood platelets, and accommodation of a confluent monolayer of endothelial cells. The goat experiments showed patency of the coated grafts in three of the eight cases. The sheep experiments were not useful for the evaluation of the dipyridamole coating because deterioration of the polyurethane material was observed. The in vivo results indicate that the dipyridamole coating may positively influence the patency rate, probably because the coating promotes the growth of an endothelial cell lining. The sheep data show, however, that the limited stability of the Chronoflex(R) material precludes its issue for the construction of permanent small-bore vascular grafts.

Animals↗
PubMed1987

Random control trial of a short course of aspirin and dipyridamole (Persantin) for femorodistal grafts.

The effect of a short course of anti-platelet agents, started preoperatively, on the patency of femorodistal bypass grafts is unknown. One hundred and forty-eight such grafts were randomized to act as controls or to receive dipyridamole 200 mg b.d. for 48 h pre-operatively and dipyridamole 200 mg b.d. with aspirin 300 mg daily for 6 weeks after surgery. Patients were well-matched and the mean pre-operative pressure index of 0.37 rose to 0.78 during the first postoperative week. No deaths were attributable to the treatment. Ninety-three grafts were autogenous vein and the remainder were prosthetic (GORE-TEX (PTFE), human umbilical vein or externally supported Dacron). At 1 year autogenous vein cumulative patency was 75 per cent. Overall results showed higher patency in the treated group (P = 0.012) which was entirely accounted for by the difference between prosthetic dipyridamole and aspirin group (85 per cent patency) and prosthetic control groups (53 per cent patency, P = 0.005) and arose during the first postoperative month. There were 11 deaths and 8 amputations in the dipyridamole and aspirin group and 8 deaths and 12 amputations in the control group. It is concluded that a six week perioperative course of dipyridamole and aspirin allows the patency of prosthetic femorodistal bypass to approach that of autogenous vein, and the regimen therefore is recommended for patients who may require a prosthetic graft.

Aspirin↗