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PubMed1996

Usefulness of dipyridamole transesophageal echocardiography in the evaluation of myocardial ischemia and coronary artery flow.

High-dose dipyridamole transesophageal stress echocardiography has recently been proposed as a useful and safe method to assess myocardial ischemia in patients with poor transthoracic acoustic window. It has also been shown that transesophageal echocardiography (TEE) allows the study of coronary blood flow reserve (CBFR) in the left anterior descending artery (LAD). The aim of our study was to assess whether the morphologic information and pathophysiologic data on CBFR and myocardial ischemia can be collected by a single stress TEE without comprimizing its feasibility, safety and accuracy. We studied, 29 patient with known or suspected CAD (previous myocardial infarction or angina) (Group A), and as a control group, we studied 11 patients with mitral disease or mitral prostheses (Group B). All patients underwent the coronary angiography. None of Group B patients showed significant coronary artery stenosis (> 70%). In baseline conditions left ventricular wall motion and LAD coronary blood flow velocity (CBFV) were also evaluated. The following CBFV parameters were measured: maximal diastolic velocity (MaxDV), mean diastolic velocity (MnDV), maximal systolic velocity (MaxSV), mean systolic velocity (MnSV). The ratios of dipyridamole to rest maximal and o mean to diastolic velocities (MaxDV-Dip/Max DV-rest; MnDv-Dip/MnDV-rest) were measured as indexes of CBFR. No side effects were observed and the test could be completed in all patients (feasibility 100%). Wall motion analysis was adequate in all patients (feasibility 100%). Comparison between wall motion analysis was obtained and angiographic findings shown that the overall sensitivity and specificity of TEE were 84% and 93% respectively. Sensitivity for one, two and three vessel disease was 60%, 70% and 100%, respectively. LAD CBFV was adequately recorded in 85% of patients. CBFR parameters showed a significant difference between the two groups (Max DV-Dip/Max DV-rest: 1.67 +/- 0.7 vs. 2.73 +/- 0.6, P < 0.001); comparison between Group B patients and those of Group A with angiographically documented LAD stenosis showed a statistically significant difference in CBFR parameters (MaxDV-Dip/MnDV-rest, 2.73 +/- 0.6 vs. 1.65 +/- 0.7, P < 0.001, MnDV-Dip/MnDV-rest, 2.56 +/- 0.5 vs. 1.69 +/- 0.6 < 0.001). We conclude that transesophageal stress echocardiography is a useful method to study CAD and that it is possible to assess both morphologic and pathophysiologic information during a single examination.

Angina Pectoris↗

PubMed1976

Effect of dipyridamole on human platelet phospholipids.

The effect of dipyridamole on platelet phospholipids has been studied. After the platelet incubation with dipyridamole, a 38% reduction in the concentration of the sphingomyelin and a 21% increase in phosphatidyl choline were produced.

Blood Platelets↗

PubMed2001

The use of L-arginine [correction of F-arginine] and phosphodiesterase inhibitor (dipyridamole) to wean from inhaled nitric oxide.

A full-term, female neonate developed acute hypoxemic respiratory failure complicated by persistent pulmonary hypertension of the newborn (PPHN), and responded to high-frequency oscillatory ventilation (HFOV) and inhaled nitric oxide (iNO). Discontinuation of iNO was attempted three times and was followed by severe desaturation due to right-to-left shunt through the patent ductus arteriosus and patent foramen ovale. As a result of iNO dependency state and rebound pulmonary hypertension, the neonate was maintained on iNO therapy for dipyridamole alone was unsuccessful. However, successful discontinuation of iNO therapy was achieved by combination of L-Arginine and dipyridamole. Exogeous NO may lead to down regulation of endogenous NO production, and further lead to rapid hydrolization of cyclic guanosine 3', 5' monophosphate (cGMP), the smooth muscle relaxant, by the enzyme phosphodiesterase. Moreover L-Arginine, the precursor for the formation of endogenous NO, has been found to be deficient in neonates with PPHN, so we speculated that by inhibiting phosphodiesterase and administrating L-Arginine smooth muscle relaxation occurred, and consequent weaning from iNO was achieved.

Arginine↗

PubMedDate not supplied

Dipyridamole technetium 99m sestamibi myocardial tomography as an independent predictor of cardiac event-free survival after acute ischemic events.

BACKGROUND: A total of 137 consecutive patients with recent uncomplicated myocardial infarction (n = 31) or unstable angina (n = 106) were studied to determine the relative prognostic value of predischarge clinical risk stratification and intravenous dipyridamole stress sestamibi (MIBI) myocardial tomography in patients unable to exercise maximally after an acute ischemic coronary event. METHODS AND RESULTS: Patients were followed up after the index study for 10 +/- 5 months (range 1 to 23 months) to ascertain cardiac events that occurred in 20 patients (15%): nonfatal myocardial infarction (n = 5) or cardiac death (n = 15). Cardiac event rates were 35% in patients with a recent myocardial infarction and 8% in the group with unstable angina (p < 0.001). Patients with these cardiac events had more frequent abnormal MIBI study results, fixed defects, and reversible plus fixed (combined) defects (all p < 0.05). The univariate relative risk of death or myocardial infarction associated with an abnormal MIBI study was 6.0 (95% confidence limits 0.8 to 44.7). Multivariate stepwise logistic regression models identified an abnormal MIBI study and either fixed or reversible MIBI defects as being predictive of death or myocardial infarction (all p < 0.05). The Mantel-Haentzel 1-year cardiac event-free survival rate was excellent in 27 patients with a normal MIBI single-photon computed emission tomographic scan (100%) but significantly reduced in the 110 patients with an abnormal MIBI study (80%; p < 0.05 vs normal subjects). The presence of combined MIBI defects was associated with the poorest event-free survival rate (66%; difference not significant vs fixed or reversible defects only). CONCLUSION: We conclude that predischarge dipyridamole MIBI tomography provided independent prognostic information in this population of patients who were unable to exercise after a recent acute ischemic coronary event.

Aged↗

PubMed1992

Failure of negative dipyridamole thallium scans to predict perioperative myocardial ischaemia and infarction.

Three cases of postoperative myocardial infarction are reported in patients with normal or fixed defects on preoperative dipyridamole thallium scans (interpreted as "negative" for active cardiac ischaemic risk). All patients were monitored with an ambulatory electrocardiographic recorder from the evening before surgery through the first two postoperative days. Two of the patients demonstrated preoperative or early postoperative ischaemia, suggesting that the test was a false negative. The third patient did not demonstrate ischaemia during the period of monitoring, but developed a myocardial infarction during the third postoperative day, suggesting progression of the underlying coronary artery disease. Preoperative dipyridamole thallium imaging may result in false negative scans in selected high-risk populations.

Aged↗

PubMed2005

Dipyridamole-dobutamine stress echocardiography for the detection of myocardial ischemia in patients with hypertension.

PURPOSE: To assess the value of dipyridamole-dobutamine stress echocardiography test (Dip-Dob SET) in detecting myocardial ischemia in hypertensive patients with chest pain and to compare it with the results of the dipyridamole-atropine stress echocardiography test (Dip-Atro SET). PATIENTS AND METHODS: 127 consecutive hypertensives with chest pain (82 male, mean age 54.5+/-7.9 years) and nondiagnostic exercise stress test were evaluated. Patients were randomly assigned to receive dobutamine 5-40 microg/kg/min (Dip-Dob group, 55 patients) or atropine 0.25 mg in four divided doses up to 1 mg (Dip-Atro group, 72 patients), if high Dip SET was negative (Dip up to 0.84 mg/kg over 10 min). 84 patients underwent coronary angiography (42 in the Dip-Atro and 42 in the Dip-Dob group). RESULTS: 76 tests were positive for new dyssynergy (16 segment/4-grade model of wall motion analysis), 39 in the Dip-Atro and 37 in the Dip-Dob group, 42 were negative, and nine were stopped due to non-life-threatening side effects, four in the Dip-Atro and five in the Dip-Dob group. Delta wall motion score index (WMSI) was significantly higher in the Dip-Dob than the Dip-Atro group (0.34+/-0.3 vs. 0.21+/-0.4; p<0.01). Coronary artery disease (>or= 50% diameter stenosis) was found in 56/84 patients, 30 patients had multivessel disease (14 in the Dip-Atro and 16 in the Dip-Dob group; p>0.05). Sensitivity, specificity, diagnostic accuracy, positive predictive value, and negative predictive value were 92.9%, 78.6%, 88.1%, 89.7%, and 84.6% versus 89.3%, 92.9%, 90.5%, 96.2%, and 81.2% (p>0.05, Dip-Dob vs. Dip-Atro). CONCLUSION: There was no significant difference in feasibility, safety and diagnostic accuracy between the Dip-Dob and Dip-Atro test. The Dip-Dob test showed more pronounced ability to provoke myocardial ischemia than the Dip-Atro test, expressed as a higher delta WMSI. Both tests confirmed high diagnostic accuracy of pharmacological stress echocardiography in hypertensive patients.

Dipyridamole↗

PubMed2003

Sensitive and simple determination of the vasodilator agent dipyridamole in pharmaceutical preparations by phosphorimetry.

The applicability of heavy atom-induced room-temperature phosphorescence to pharmaceutical samples is demonstrated in this work. Thus a new, simple, rapid, and selective phosphorimetric method for dipyridamole determination is proposed. The phosphorescence signals are a consequence of intermolecular protection when analytes are exclusively in the presence of heavy atom salts and sodium sulfite as an oxygen scavenger to minimize RTP quenching. The determination was performed in 0.1 mol L(-1) thallium(I) nitrate and 8 mmol L(-1) sodium sulfite at a measurement temperature of 20 degrees C. The phosphorescence intensity was measured at 635 nm, with excitation at 305 nm. Phosphorescence was easily developed; a linear concentration range was obtained between 0 and 100 ng mL(-1) with a detection limit of 940 ng L(-1), an analytical sensitivity of 2.5 ng mL(-1), and a standard deviation of 2.7% at 60 ng mL(-1) concentration. The method has been successfully applied to the analysis of dipyridamole in a unique Spanish commercial formulation containing 100 ng mL(-1) per capsule. The recovery was 101.6% with 6.5% standard deviation of analytical measurement. The method using the standard addition methodology has been validated.

Calibration↗

PubMedDate not supplied

Follow-up assessment of the collateral circulation in patients with Kawasaki disease who underwent dipyridamole stress technetium-99m tetrofosmin scintigraphy.

To assess the alteration of myocardial ischemic findings and the role of collateral vessels in patients with Kawasaki disease (KD), we used dipyridamole stress technetium-99m tetrofosmin (Tf) single photon emission computed tomography (SPECT). A comparison study of coronary angiography and dipyridamole stress (0.70 mg/kg) Tf-SPECT was repeated at least twice in 20 patients. The subjects included 7 patients with coronary stenosis, 1 with pre- and post-coronary artery bypass grafting (CABG) due to coronary stenosis, 1 with progression to coronary stenosis, and 11 with persistent coronary aneurysms. In the stenosis group, Tf-SPECT revealed that 6 of the 7 patients had some degree of ischemic findings, and 5 of these 6 did not show any change in their ischemic findings during follow-up. In 1 patient, the ischemic findings changed according to the collateral circulation changes. The patient who underwent CABG had pre-CABG ischemic changes that disappeared after CABG. In the patient whose coronary arteries progressed to stenosis, the ischemic findings progressed as the coronary stenosis progressed. In the persistent aneurysm group, there were no ischemic findings. In the future Tf-SPECT may become one of the most useful methods for monitoring the progressive changes of myocardial ischemia in KD.

Adolescent↗

PubMed2001

[Does early high dosage dipyridamole in prevention of secondary stroke induce cardiac events?].

In a post hoc analysis of the European Stroke Prevention Study 2 (ESPS2), we investigated whether dipyridamole given as antiplatelet drug in patients with TIA or stroke increases the risk of cardiac events. ESPS2 was a secondary prevention trial including 6602 patients with TIA or stroke. Patients were randomized into one of four treatment arms: 2 x 25 mg acetylsalicylic acid (ASA), 2 x 200 mg slow release dipyridamole (DP), the combination of DP and ASA and placebo. DP did not result in a higher number of cardiac events, e.g., angina pectoris, myocardial infarction or death. The combination of ASA plus DP was superior to either drug alone in the prevention of strokes.

Administration, Oral↗

PubMed2005

Effect of combined treatment with aspirin and dipyridamole on oxidative homeostasis in mouse serum.

Using the method of peroxidative luminol-dependent chemiluminescence we showed that combined treatment with aspirin in low dose and dipyridamole corrects imbalance in oxidative homeostasis in mouse serum. This state resulted from a sharp increase in prooxidant processes after platelet disaggregation with normal dose of aspirin or dose-dependent inhibition of free radical processes with dipyridamole.

Animals↗

PubMed1975

Effects of dipyridamole and acetylsalicylic acid on platelet functions in patients with aortic ball-valve prostheses.

The effects of dipyridamole and ASA on platelet functions were studied in patients with aortic ball-valve prostheses. Before ingestion, platelet adhesiveness was markedly reduced and platelet survival time slightly, but insignificantly shortened. ASA prolonged the bleeding time, reduced collagen-induced platelet aggregation, and inhibited secondary aggregation initiated by adrenalin. Similar effects were obtained with 2 Gm. of ASA alone as with 1 Gm. daily in combination with 225 mg. of dipyridamole. Platelet adhesiveness remained low. Depyridamole alone, 375 mg. daily, did not influence any of these parameters. The mean platelet half-life was prolonged from 3.52 to 3.72 days by each drug and to 4 days by the combined treatment. None of the differences was, however, statistically significant. A clinical study with ASA has been started in a larger series of patients to evaluate the effect on arterial thromboembolism.

Aortic Valve↗

PubMed1988

Short-term infarct vessel patency with aspirin and dipyridamole started 24 to 36 hours after intravenous streptokinase.

The duration of intravenous heparin therapy required to maintain patency of the infarct-related artery after intravenous streptokinase is uncertain. Twenty-eight patients were prospectively treated with 1.5 million units of intravenous streptokinase within 4 hours of onset of chest pain. Intravenous heparin was begun after the streptokinase infusion was complete and was discontinued within 36 hours. Aspirin, 325 mg daily, and dipyridamole, 75 mg three times a day, was begun before the heparin was discontinued. Coronary angiography was performed both at 2 hours after completion of the streptokinase infusion and again at a mean of 8.7 (+/- 3.2) days after the initial catheterization. One patient died after treatment with streptokinase but before early angiography. In 21 of 27 patients (78%), Thrombolysis in Myocardial Infarction trial (TIMI) grade 2 or 3 perfusion in the infarct vessel was observed on initial angiography. Repeat angiograms were available in 17 of the 21 patients with initially patent vessels. Continued patency (TIMI grade 2 or 3) was found in 15 of the 17 patients (88%). Two of the four patients who did not undergo repeat angiography died, and the remaining two patients required coronary artery bypass grafting for unstable angina. Bleeding complications occurred in 6 of 27 patients (22%), with two (7%) requiring surgical evacuation of a groin hematoma. There were no instances of intracerebral bleeding and only two patients required transfusions. Thus, the combination of aspirin and dipyridamole following 36 hours of systemic heparinization after intravenous streptokinase infusion is associated with a reocclusion rate comparable to that which has been reported for more prolonged systemic anticoagulation with fewer hemorrhagic complications.

Angiography↗

PubMed1991

Single-photon emission computed tomographic thallium imaging with adenosine, dipyridamole, and exercise.

Stress thallium imaging is a sensitive technique for detecting coronary artery disease, particularly in those patients with multivessel disease. Single-photon emission computed tomography (SPECT) is superior to planar imaging; because of improved image quality and lack of overlap between normal and abnormal segments, SPECT has greater ability to detect diseased arteries. The inherent three-dimensional nature of the data presentation suggests the feasibility of quantifying the extent of myocardium at risk. Pharmacologic stressors such as adenosine and dipyridamole allow imaging with thallium (and probably other perfusion agents) even in patients who are not candidates for exercise testing or who cannot achieve adequate levels of exercise. Studies suggest that adenosine has unique advantages for use with SPECT perfusion imaging with a high degree of accuracy. In our experience the sensitivity of detecting one-vessel disease is higher with adenosine-thallium imaging than in exercise SPECT thallium imaging. The degree of coronary hyperemia is greater and the duration of action is shorter with adenosine than with dipyridamole.

Adenosine↗

PubMed1991

Dipyridamole perfusion scintigraphy: the experience with its application in one hundred seventy patients with known or suspected unstable angina.

We evaluated the safety, accuracy, and potential clinical utility of intravenous dipyridamole perfusion scintigraphy with thallium-201 in 170 patients, 78 with suspected and 92 with known unstable angina. All had coronary angiography. Noncardiac side effects (26%), induced chest discomfort (44%), and ST segment changes (12%) were similar in the two groups. No significant arrhythmias occurred. Two patients had prolonged chest pain, both with extensive reversible image abnormalities and associated creatinine kinase-MB release. Both had elective bypass surgery. Twenty-eight patients had normal coronary arteries, and 35 had single-vessel disease. Scintigraphic per patient sensitivity and specificity were 91% and 79% with a per vessel sensitivity of 74% and a per vessel specificity of 78% without between-group differences. During a brief follow-up period, 62 patients with image abnormalities had coronary revascularization, and there were seven deaths without intergroup differences. In a similar patient group that did not have angiography, scintigraphic defects were less frequent and less extensive, revascularization was not performed, and subsequent deaths occurred less often. Dipyridamole perfusion scintigraphy is an accurate alternative to exercise testing in the evaluation of patients with unstable angina pectoris. Although not without risk, the method appears relatively safe and should be considered as a guide to diagnosis, and probably to prognosis and management.

Adult↗

PubMed1992

Prognostic value of dipyridamole thallium-201 scintigraphy in patients with stable chest pain.

The usefulness of dipyridamole testing with planar thallium-201 scintigraphy for assessing risk of subsequent cardiac events was evaluated in 373 patients with stable chest pain. Follow-up information was complete in 362 patients (mean age 64 +/- 9 years). During an average follow-up period of 18 months, cardiac events occurred in 59 patients--unstable angina in 27, nonfatal acute myocardial infarction in 11, and death from cardiac causes in 21. A history of previous myocardial infarction, congestive heart failure, or coronary bypass surgery before the study, or the presence of an abnormal scan or one with a fixed perfusion defect was associated with a significantly increased frequency of subsequent cardiac events (p less than 0.05). However, the presence of a reversible perfusion defect was not associated with increased risk (p = 0.1872). Stepwise logistic regression showed that a history of coronary artery bypass surgery before the study and the presence of a fixed perfusion defect were the only variables with independent predictive value for occurrence of a subsequent cardiac event (p less than 0.05). Survival analysis revealed a significantly increased cardiac event rate in patients with abnormal scans compared with those with normal scans over a 30-month follow-up period (p less than 0.01). We conclude that dipyridamole testing with thallium-201 scintigraphy can provide prognostic information concerning risk of future cardiac events in patients with stable chest pain. The presence of a fixed perfusion defect in particular identifies patients at increased risk.

Angina Pectoris↗

PubMed1993

Biplane transesophageal pacing echocardiography compared with dipyridamole thallium-201 single-photon emission computed tomography in detecting coronary artery disease.

TPE is a new diagnostic technique that uses simultaneous graded transesophageal left atrial pacing and biplane transesophageal echocardiography for the detection of pacing-induced wall motion abnormalities. In a prospective study 30 patients underwent biplane TPE, dipyridamole thallium-201 single-photon emission computed tomography (SPECT), and coronary arteriography. The sensitivity (86% vs 95%, p = not significant [NS]), specificity (89% vs 56%, p = NS), positive predictive value (95% vs 73%, p = NS), and negative predictive value (83% vs 83%, p = NS) of biplane TPE and thallium-201 SPECT in identifying patients with significant coronary artery disease was similar. In the 90 vascular territories analyzed, the agreement between biplane TPE and thallium-201 SPECT for presence or absence of significant disease was 71%. Analysis of the three major vascular territories demonstrated that each imaging modality had a high sensitivity and specificity in the left anterior descending and right coronary artery segments. However, the two techniques demonstrated poorly sensitivity in the segmental distribution of the circumflex coronary artery. In conclusion, biplane TPE compared favorably with thallium-201 SPECT in terms of safety and accuracy for detecting significant coronary artery disease. Accordingly, biplane TPE may be a suitable alternative for those patients with nondiagnostic thallium-201 SPECT studies and in those with contraindications to adenosine or dipyridamole.

Aged↗

PubMed1979

Reduction of intimal thickening in canine coronary bypass vein grafts with dipyridamole and aspirin.

The potential benefit of platelet inhibitor drugs on coronary arterial bypass vein grafts was assessed in dogs with magnification-corrected angiographic luminal measurements and quantitative histologic evaluation of the vein grafts. There were 11 control animals and 11 animals treated with dipyridamole, 55 mg/day, plus aspirin, 325 mg/day. Eighteen animals with patent grafts were studied when electively killed 2, 4 or 6 months after grafting. At 14 days, there was greater angiographic narrowing in the most distal 1 cm of vein grafts in control than in treated dogs (P less than 0.01). This same angiographic narrowing persisted in control dogs until they were killed (P less than 0.03). Computer-assisted measurements of the entire area of intimal thickening were done on vein graft cross sections taken 1 cm from the distal anastomosis. The circumference of the vein grafts at the intimal-media junction was measured from the same section and the potential maximal luminal area calculated. The calculated luminal narrowing due to intimal thickening was greater in control than in treated dogs (P less than 0.03). These data correlate well with the demonstrated angiographic narrowing. The findings indicate that the degree of early intimal thickening that persists 2 to 6 months postoperatively in canine coronary bypass vein grafts may be reduced by the platelet inhibitor combination of dipyridamole plus aspirin.

Animals↗

PubMed1981

Reduction of thrombosis in canine coronary bypass vein grafts with dipyridamole and aspirin.

The potential benefit of platelet inhibitor drugs in reducing early thrombosis of coronary arterial vein bypass grafts was assessed in dogs. There were 26 control dogs and 24 dogs treated with dipyridamole, 55 mg/day plus aspirin, 325 mg/day. The dogs in both groups were killed at 2 hours and 1, 2, 3, 7 and 14 days after operation. The grafts were perfused with fixative in vivo, harvested and examined with light microscopy. Severe alterations of the graft wall were observed in the dogs in both groups. The grafts in the control group had a high incidence rate of thrombosis, which occurred early after the operation; those in the treated group had a significantly reduced incidence of thrombosis (p = 0.025). Our study indicates that a combined regimen of dipyridamole and aspirin is effective in reducing early graft thrombosis in dogs.

Animals↗