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PubMedDate not supplied

QRS score versus ST-segment changes in patients undergoing Tl-201 scintigraphy using dipyridamole infusion.

BACKGROUND: ST-segment changes after dipyridamole infusion followed by handgrip isometric stress lack diagnostic value, because of the low sensitivity for the detection of coronary artery disease (CAD). In addition, an abnormal QRS score during exercise had a greater diagnostic ability than ST-segment changes to detect CAD. This study was undertaken to compare QRS score values with ST-segment changes during thallium 201 scintigraphy via dipyridamole infusion. METHODS AND RESULTS: In this study 128 patients (101 men and 27 women), aged 53 to 72 years (mean, 59 +/- 8 years), underwent Tl-201 scintigraphy after dipyridamole infusion and handgrip isometric stress, as well as coronary angiography. QRS score values and ST-segment changes after dipyridamole infusion and handgrip isometric stress were also estimated. CAD was detected in 96 patients (75%), whereas normal coronary arteries were found in 32 (25%). According to scintigraphic data, 48 patients (37%) had no reversible perfusion defects whereas 80 (63%) had at least 1 reversible perfusion defect. Sensitivities for an abnormal QRS score and ST-segment deviation were 68% versus 18% ( P < .01) for detection of CAD and 75% versus 19% for detection of myocardial ischemia ( P < .01), respectively. Similar specificities were found ( P = not significant). CONCLUSIONS: An abnormal QRS score significantly improves the low sensitivity of ST-segment changes for the detection of myocardial ischemia and CAD by use of Tl-201 scintigraphy with dipyridamole infusion and handgrip isometric stress.

Aged↗
PubMed1990

Perioperative and long-term prognostic value of intravenous dipyridamole thallium scintigraphy in patients with peripheral vascular disease.

The prognostic value of long-term risk stratification of patients with peripheral vascular disease who undergo intravenous dipyridamole thallium scintigraphy has not been well studied. We screened 131 patients with peripheral vascular disease who underwent intravenous dipyridamole thallium testing to determine cardiac event rates over an average follow-up of 18 +/- 10 months. Of the 131 patients, 111 subsequently had peripheral vascular surgery. The patients with abnormal thallium scans after dipyridamole had a significantly higher risk of death or myocardial infarction, both in the perioperative phase (7% versus 0%; p less than 0.001) and at late follow-up (17% versus 6%; p less than 0.01). The risk of a cardiac event was two-fold greater when a reversible as compared to a fixed thallium defect was present. Multivariate analysis selected the number of thallium segments with perfusion defects, prior history of angina pectoris, and chest pain during dipyridamole testing as perioperative predictors of a cardiac event. A reversible thallium defect was the only predictor of death or nonfatal myocardial infarction during late follow-up. Thus intravenous dipyridamole thallium scintigraphy is a useful noninvasive test for risk stratification of patients before peripheral vascular surgery and provides prognostic information as to the risk of a cardiac event in the 2-year period after the test. A reversible thallium defect is associated with a significant increased risk and would indicate that coronary angiography should be considered and preoperative coronary revascularization.

Aged↗
PubMed1996

Comparison of adenosine to dipyridamole in degree of coronary hyperemic response in heart transplant recipients.

Transplant coronary vasculopathy is associated with endothelial dysfunction. Microvascular function, assessed as coronary flow reserve, has been reported to be normal. We used intracoronary ultrasound technology to simultaneously assess conductance and resistance vessel function in response to standard dosages of the vasodilators adenosine and dipyridamole. Coronary hemodynamic changes were assessed in 11 heart transplant recipients, at a mean duration of 784 +/- 516 days after transplantation, using a 3.2Fr or 4.3Fr, 30-MHz ultrasound imaging catheter over a 0.014-inch Doppler guidewire. Measures of coronary average peak flow velocity (APV) and coronary cross-sectional area (CSA) were used to calculate volumetric flow during intravenous infusions of adenosine (140 micrograms/kg/min over 4 minutes) and dipyridamole (140 micrograms/kg/min over 4 minutes). Flow reserve was assessed as a ratio of maximal pharmacologically induced flow to steady baseline flow before infusion. Increase in APV (261.9% vs 194.6%, p = 0.005), lumenal CSA (+11.8% vs +4.2%, p = 0.01), peak volumetric blood flow (515.8 vs 317.2 ml/min, p = 0.007), and coronary flow reserve (2.93 +/- 0.74 vs 1.99 +/- 0.53, p < 0.001) were higher with adenosine than dipyridamole. Both agents caused similar decreases in systemic blood pressure and little change in heart rate. Adenosine appears to be a more potent coronary vasodilator than dipyridamole in denervated human transplant subjects. Adenosine has a vasodilator effect at the epicardial and microvascular levels, resulting in an overall increase in volumetric flow. Flow reserve in response to both endothelium-independent agents is decreased in comparison with previously established values, but the attenuation is greater with dipyridamole.

Adenosine↗
PubMed1986

Comparison of cod-liver oil and aspirin-dipyridamole for the prevention of intimal hyperplasia in autologous vein grafts.

The combination of aspirin and dipyridamole is currently used to prevent intimal hyperplasia and to improve long-term vein graft patency following myocardial revascularization. Preliminary studies indicate that cod-liver oil, rich in eicosapentaenoic acid, an unsaturated fatty acid, may also be effective in the prevention of intimal hyperplasia. Twenty-four mongrel dogs were used to compare the effectiveness of aspirin-dipyridamole and cod-liver oil on vein graft intimal hyperplasia following arterial bypass. Forty-eight segments of undistended autologous external jugular vein were interposed between bilaterally divided femoral arteries. All animals received a 2% cholesterol diet for 1 week before and 6 weeks after operation. Eight controls received the diet alone. Eight other animals received dipyridamole (2.5 mg per kilogram of body weight) two days before operation and dipyridamole (2.5 mg/kg) and aspirin (30 mg/kg) daily for 6 weeks after operation. Another 8 animals received cod-liver oil containing 1.8 gm of eicosapentaenoic acid daily 1 week before and for 6 weeks following operation. Serum cholesterol increased similarly in all groups; it rose from 4.5 +/- 0.2 mm/L to 8.3 +/- 0.8 mm/L in the controls, to 7.2 +/- 0.5 mm/L in the aspirin-dipyridamole group, and to 7.1 +/- 0.5 mm/L in the cod-liver oil group (p less than 0.01). Prothrombin time, partial thromoboplastin time, total platelet counts, and bleeding times were unchanged. Intimal hyperplasia was measured at 6 weeks with a Zeiss computerized microscope; 376 +/- 25 measurements were made from each graft. The intima increased from 4.5 +/- 0.2 to 83 +/- 10 micron in the control dogs.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1998

Preoperative assessment of coronary artery disease in aortic stenosis: a dipyridamole echocardiographic study.

BACKGROUND: The aim of this study was to establish the feasibility, safety, and diagnostic accuracy of the dipyridamole echocardiography test in patients with severe aortic valve stenosis for noninvasive detection of coexisting coronary artery disease. METHODS: The high-dose dipyridamole echocardiography test was performed in 52 patients with severe aortic stenosis; all patients also underwent coronary angiography, independent of test results, before cardiac operation. RESULTS: The dipyridamole echocardiography test was completed without major complications. One patient had transient atrial fibrillation that was reversed by aminophylline. Thirty-one patients (60%) had a negative test result; all had normal coronary arteries. Ten of the 21 patients (48%) with a positive test result had coexisting coronary artery disease. The positive predictive value of the dipyridamole echocardiography test for detection of coronary disease in patients with severe aortic stenosis was 48%. The negative predictive value was 100%. The sensitivity was 100% and the specificity was 74%. CONCLUSIONS: Dipyridamole echocardiography is a safe and feasible tool in patients with severe aortic stenosis eligible for a cardiac operation. A negative test result reliably rules out a significant stenosis, whereas a positive one is much less accurate in predicting coronary artery disease.

Aortic Valve Stenosis↗
PubMed1999

Inhibition by dipyridamole of neutrophil adhesion to vascular endothelium during coronary bypass surgery.

BACKGROUND: Release of reactive oxygen radicals by activated neutrophils and neutrophil adhesion to endothelial cells have been observed after cardiopulmonary bypass. The aim of the present study was to evaluate the effects of preoperative dipyridamole treatment on neutrophil superoxide anion generation and endothelial cell-neutrophil interactions. METHODS: Two groups of patients scheduled for elective coronary artery bypass grafting were randomized to receive oral dipyridamole or a placebo. Nitro blue tetrazolium scores of circulating neutrophils, neutrophil CD11b/CD18 expression, and their adhesion to human umbilical vein endothelial cells were assayed before anesthesia, 30 minutes after the beginning of cardiopulmonary bypass, at the end of bypass, and 60 minutes postoperatively. RESULTS: In both groups, cardiopulmonary bypass resulted in a significant increase in nitro blue tetrazolium scores in circulating neutrophils as well as a significant increase in both neutrophil CD11b/CD18 expression and neutrophil adhesion to endothelial cells. The extent of neutrophil superoxide anion generation was higher in the control group; a significant (p < 0.01) reduction in neutrophil adhesion to endothelial cells was observed 1 hour postoperatively in the dipyridamole group. In 5 patients treated with dipyridamole, the incubation of activated polymorphonuclear leukocytes with adenosine deaminase significantly increased their adhesion to endothelial cells (p < 0.05). CONCLUSIONS: Our study demonstrated that preoperative treatment with oral dipyridamole significantly reduces both neutrophil superoxide anion generation and extent of neutrophil adhesion to endothelial cells after coronary bypass grafting procedures with cardiopulmonary bypass. The mechanism is probably mediated by endogenous adenosine.

Adenosine Deaminase↗
PubMed1986

Non-invasive detection of coronary artery disease by body surface electrocardiographic mapping after dipyridamole infusion.

Electrocardiographic changes after dipyridamole infusion (0.568 mg/kg/4 min) were studied in 41 patients with coronary artery disease and compared with those after submaximal treadmill exercise by use of the body surface mapping technique. Patients were divided into three groups; 19 patients without myocardial infarction (non-MI group), 14 with anterior infarction (ANT-MI) and eight with inferior infarction (INF-MI). Eighty-seven unipolar electrocardiograms (ECGs) distributed over the entire thoracic surface were simultaneously recorded. After dipyridamole, ischemic ST-segment depression (0.05 mV or more) was observed in 84% of the non-MI group, 29% of the ANT-MI group, 63% of the INF-MI group and 61% of the total population. Exercise-induced ST depression was observed in 84% of the non-MI group, 43% of the ANT-MI group, 38% of the INF-MI group and 61% of the total. For individual patients, there were no obvious differences between the body surface distribution of ST depression in both tests. The increase in pressure rate product after dipyridamole was significantly less than that during the treadmill exercise. The data suggest that the dipyridamole-induced myocardial ischemia is caused by the inhomogenous distribution of myocardial blood flow. We conclude that the dipyridamole ECG test is as useful as the exercise ECG test for the assessment of coronary artery disease.

Adult↗
PubMed1998

Dipyridamole attenuates rebound pulmonary hypertension after inhaled nitric oxide withdrawal in postoperative congenital heart disease.

OBJECTIVE: Inhaled nitric oxide therapy causes selective and sustained pulmonary vasodilation in patients with pulmonary hypertension; however, attempts to discontinue inhaled nitric oxide therapy may be complicated by abrupt life-threatening events. Dipyridamole, a cyclic guanosine monophosphate-specific phosphodiesterase inhibitor, blocks the hydrolysis of cyclic guanosine monophosphate in vascular smooth muscle cells. METHODS: We studied 23 consecutive children who were treated with inhaled nitric oxide because of clinically significant pulmonary hypertension after surgery for congenital heart disease. Inhaled nitric oxide therapy was withdrawn before and after dipyridamole treatment of children in whom sustained elevations of pulmonary artery pressure developed for over 30 minutes. RESULTS: In 7 of 23 children, inhaled nitric oxide withdrawal caused a 40% increase in pulmonary artery pressure, a 17% decrease in systemic venous oxygen saturation, and a 46% increase in the ratio of mean pulmonary artery pressure to aortic pressure. Compared with children who had no significant increase in pulmonary artery pressure, children who experienced the development of prolonged pulmonary hypertension after inhaled nitric oxide therapy withdrawal had higher mean pulmonary artery pressure immediately before inhaled nitric oxide withdrawal (22 +/- 1 mm Hg versus 27 +/- 2 mm Hg; p = 0.04) and received inhaled nitric oxide for a longer duration (2 +/- 1 days versus 4 +/- 1 days; p = 0.01). Dipyridamole therapy attenuated the rise in pulmonary artery pressure and fall in systemic venous oxygen saturation in all six patients studied with rebound pulmonary hypertension after withdrawal of inhaled nitric oxide. CONCLUSION: We conclude that dipyridamole therapy acutely attenuates the adverse hemodynamic effects of rapid withdrawal of inhaled nitric oxide therapy. Children with higher pulmonary artery pressure and who are treated with inhaled nitric oxide for a longer duration may be at increased risk for adverse hemodynamic effects of inhaled nitric oxide therapy withdrawal. We speculate that dipyridamole therapy may sustain elevations of smooth muscle cyclic guanosine monophosphate induced by inhaled nitric oxide and that phosphodiesterase activity contributes to acute pulmonary hypertension after inhaled nitric oxide withdrawal.

3',5'-Cyclic-GMP Phosphodiesterases↗
PubMed1998

Secondary stroke prevention with low-dose aspirin, sustained release dipyridamole alone and in combination. ESPS Investigators. European Stroke Prevention Study.

Patients who had survived a stroke or transient ischaemic attacks (TIA) were admitted to a trial of low-dose aspirin (50 mg) alone, sustained release dipyridamole (400 mg/day) alone, or a combination of the two agents, and results compared with a placebo over 24 months. This low-dose aspirin regimen produced in pairwise comparisons a significant risk reduction of 18% for stroke, 13% for stroke and/or death but no reduction in all cause mortality. The sustained release dipyridamole produced a significant risk reduction of 16% for stroke, 15% for stroke and/or death but no significant reduction of mortality. In combination, aspirin and dipyridamole produced a risk reduction of 37% in stroke, 24% in stroke and/or death, and no reduction in mortality. Similar findings were found in TIA, which was a secondary endpoint. These results are highly significant in comparison with placebo. As expected, there were enhanced reports of alimentary side-effects in the aspirin groups and also enhanced bleeding. Dipyridamole was associated with a slight increase in headache, which resolved in most patients if therapy was continued. The conclusions are that 50 mg/day of aspirin alone or 400 mg/day of sustained release dipyridamole alone are equally effective in stroke and TIA prevention. When used in combination the effects were additive and were significantly more effective than the single agents.

Aged↗
PubMed2001

Analysis of trials evaluating combinations of acetylsalicylic acid and dipyridamole in the secondary prevention of stroke.

BACKGROUND: Stroke is one of the leading causes of morbidity and mortality in the United States. Patients who suffer a cerebrovascular event are at high risk of a recurrence, and secondary prevention is crucial to reducing the burden of cerebrovascular disease. Acetylsalicylic acid (ASA, aspirin) is an established method of stroke prophylaxis. OBJECTIVE: This review investigates whether the addition of dipyridamole to ASA further reduces the risk of stroke recurrence. METHODS: To identify clinical trials of the use of combinations of ASA and dipyridamole in the prevention of recurrent stroke in patients who have suffered a first stroke or transient ischemic attack, the English-language literature was searched from 1966 through May 2001 using the MEDLINE, International Pharmaceutical Abstracts, EMBASE, and BIOSIS databases. The search terms used were dipyridamole, aspirin, acetylsalicylic acid, ischemic stroke, and cerebrovascular disorders. CONCLUSIONS: Of the 5 published studies, 3 earlier studies detected no differences in outcome when dipyridamole was added to ASA therapy for stroke prophylaxis. Two more recent trials found that the addition of dipyridamole to ASA therapy provided further reduction in the risk of secondary cerebrovascular events compared with placebo and with ASA alone. Further studies are needed to confirm long-term benefit.

Aged↗
PubMed1982

Decrease of carbon tetrachloride liver toxicity in rats given dipyridamole.

The influence of Dipyridamole on acute hepatotoxicity has been studied in male SD-JCL rats doses with carbon tetrachloride. High single oral doses of Dipyridamole lowered the serum enzyme activity and reduced significantly the area % of hepatic necrosis and hydropic degeneration, but not of steatosis. Dipyridamole was effective from 1 hr before through 6 hrs after the oral administration of CCl4. Doses below 1,000 mg/kg Dipyridamole were less effective. No delay in the onset of CCl4-induced liver damages was observed. Dipyridamole was also effective when CCl4 toxicity was enhanced by isopropanol.

1-Propanol↗
PubMed2000

Fluorescence quenching of dipyridamole associated to peroxyl radical scavenging: a versatile probe to measure the chain breaking antioxidant activity of biomolecules.

Dypiridamole is a highly efficient chain breaking antioxidant (Iuliano et al., Free Radic. Biol. Med. 18 (1995) 239-247) with an aromatic ring system responsible for an intense absorption band in the 400-480-nm region and for an intense fluorescence. Dipyridamole fluorescence is quantitatively quenched upon reaction with peroxyl radicals. In the presence of a flux of peroxyl radicals generated by thermal dissociation of azo-initiators, dipyridamole fluorescence decays linearly, showing a first-order reaction with respect to peroxyl radicals, and zero-order with respect to dipyridamole. The pH optimum for the fluorescence quenching is in the 7-8 range, from pH 7 to 6, the decay of fluorescence rapidly decreases to became negligible below pH 5.5. Dipyridamole consumption is blocked in the presence of an added chain breaking antioxidant for a time that is proportional to the antioxidant concentration. This effect is shown for ascorbic acid, trolox, vitamin E, uric acid, and N, N'-diphenyl-p-phenylenediamine. The slope of the linear correlation relative to trolox allows calculation of the bimolecular rate constant for a given molecule and peroxyl radicals. Comparison of data obtained by the dipyridamole consumption are comparable to values obtained by the oxygen consumption method.

Antioxidants↗
PubMed2001

Absolute quantitation of coronary steal induced by intravenous dipyridamole.

OBJECTIVE: The study was done to determine whether coronary steal (defined as an absolute decrease in perfusion from resting blood flow) is induced by intravenous (IV) dipyridamole in patients with severe coronary artery disease (CAD). BACKGROUND: Myocardial ischemia during coronary vasodilation is usually attributed to coronary steal. However, there is limited data on the absolute magnitude of coronary steal in humans. METHODS: Eighteen patients with multivessel CAD underwent dynamic positron emission tomography (PET) imaging with 13NH3 at rest and after infusion of IV dipyridamole. Eight myocardial sectors were analyzed per short axis slice and myocardial blood flow calculated with a two-compartment model in absolute terms. RESULTS: Coronary steal occurred in 8 of the 18 patients. In the 8 patients with coronary steal, myocardial blood flow decreased from 90 +/- 18 ml/100 g/min at rest to 68 +/- 27 ml/100 g/min following dipyridamole in the segments with steal, and increased from 87 +/- 19 to 138 +/- 16 ml/100 g/min following dipyridamole in the segments without steal. Significant clinical correlates of coronary steal were either ST elevation or the combination of ST depression and angina. CONCLUSIONS: Coronary vasodilation with IV dipyridamole is associated with significant reductions in blood flow to collateral-dependent myocardium consistent with coronary steal in about 45% of patients with severe CAD.

Aged↗
PubMed2003

Simultaneous analysis of wall motion and coronary flow reserve of the left anterior descending coronary artery by transthoracic doppler echocardiography during dipyridamole stress echocardiography.

BACKGROUND: Coronary flow reserve (CFR) can be measured in the left anterior descending artery (LAD) by dipyridamole transthoracic Doppler echocardiography (DTTDE). This information may critically improve the diagnostic accuracy of dipyridamole stress echocardiography, which is limited by moderate sensitivity. OBJECTIVE: We sought to assess the feasibility and accuracy of value of DTTDE. METHODS: We evaluated 752 consecutive patients (478 men; mean age, 64.7 years) referred for dipyridamole stress echocardiography. The diastolic velocity in the LAD was continuously monitored with pulsed Doppler at baseline and during hyperemia induced by the infusion of 0.84 mg/kg of dipyridamole. CFR was calculated as the ratio of maximal and basal diastolic velocity; a value < 2 was considered to indicate decreased CFR. Wall motion was assessed semiquantitatively. Coronary angiography was performed in 132 patients the week after DTTDE. RESULTS: Adequate tracings were obtained in 95% of patients studied (715 of 752). In the subset of 132 patients undergoing coronary angiography, 71 patients (group A) showed a nonsignificant (<70%) and 61 patients (group B) a significant stenosis of the LAD. In group A, 65 had a normal wall-motion response (91.5% specificity) and 19 patients showed a decreased CFR (73.2% specificity; P =.1). In group B, new wall-motion abnormalities were seen in 42 patients (68.8% sensitivity), whereas CFR was decreased in 52 patients (86.8% sensitivity; P <.02). CONCLUSION: Simultaneous assessment of wall motion and CFR of the LAD with DTTDE was highly feasible and safe. The information about CFR had a significantly higher sensitivity than the analysis of wall motion during dipyridamole stress echocardiography.

Coronary Circulation↗
PubMedDate not supplied

Pharmacologically induced myocardial ischemia: a comparison of dobutamine and dipyridamole.

The purpose of our study was to compare the ability of dobutamine and dipyridamole infusion to induce myocardial ischemia. In a population of 16 anesthetized open-chest swine, a coronary artery stenosis sufficient to abolish the hyperemic response to a 15-second total occlusion was created. Heart rate, systolic blood pressure, and dP/dt were recorded. Myocardial segment shortening was determined by sonomicrometry in all animals. In a subset of seven animals regional myocardial blood flow was measured by injection of radiolabeled microspheres. Dipyridamole was infused according to a high-dose protocol. After a washout period and reestablishment of a baseline state, dobutamine was infused incrementally. There was no significant difference between the baseline states. Dipyridamole did not affect heart rate but did significantly decrease blood pressure and rate-pressure product. Myocardial segment shortening decreased in the ischemic zone by 0.07 +/- 0.08 (p = 0.004). Dobutamine infusion significantly increased heart rate, blood pressure, and rate-pressure product. Myocardial segment shortening in the ischemic zone decreased by 0.17 +/- 0.09 (p < 0.001). Dobutamine decreased blood flow in the ischemic zone relative to baseline. Both dobutamine and dipyridamole infusion resulted in myocardial ischemia. The magnitude of the ischemic response is greater for dobutamine than for dipyridamole.

Animals↗
PubMedDate not supplied

Myocardial contrast enhancement after intravenous injection of sonicated albumin microbubbles: a transesophageal echocardiography dipyridamole study.

Myocardial opacification after intravenous injection of an echo-contrast agent is a major end point in contrast echocardiography, but it has not yet been obtained in human beings. We propose transesophageal contrast echocardiography as a clinical tool for the study of myocardial perfusion in human beings. Sonicated albumin microbubbles are bright ultrasound reflectors that cross the pulmonary vasculature after intravenous injection and show physiologic transit times through tissues. Transesophageal echocardiography uses ideal transducer frequency and acoustic window for in vivo detection of sonicated albumin microbubbles. We have studied 11 patients receiving peripheral vein bolus injection of sonicated albumin microbubbles during transesophageal echocardiography at baseline and during dipyridamole infusion. Images were recorded on videotape and digitized off-line. Quantitative measurements were made on 11 normally perfused myocardial segments by tracing a region of interest of greater than 100 pixels on frozen end-systolic frames, at baseline, and during dipyridamole infusion. Transpulmonary passage with full left ventricular cavity opacification was obtained in all injections. In 8 of 22 injections there was also transient left ventricular cavity attenuation. In all patients there was a marked opacification of the left ventricular outflow tract and aortic root. At baseline, mean signal intensity in the myocardium increased from 80 +/- 37 to 117 +/- 49 IU (p < 0.05) and during dipyridamole infusion increased from 84 +/- 28 to 146 +/- 36 IU (p < 0.001). The analysis of background-subtracted data showed that mean pixel intensity increased from baseline to dipyridamole contrast injection (from 37 +/- 15 to 62 +/- 19 IU; p < 0.01). The opacification of normally perfused left ventricular myocardium is feasible during transesophageal echocardiography because there is a significant increase in signal intensity versus background intensity. During dipyridamole infusion there is a further increase in signal intensity that probably reflects pharmacologically induced increase in myocardial blood flow.

Albumins↗
PubMed1997

Late apical filling by color Doppler M-mode during dipyridamole stress echocardiography: a useful contribution to wall motion analysis.

It has been shown that regional myocardial ischemia during angioplasty is associated with retarded apical filling. To test the importance of retarded apical filling by color Doppler M-mode to detect ischemia during dipyridamole stress echocardiography, we evaluated 29 patients (12 women, aged 57 to 87 years). High-dose dipyridamole (0.84 mg/kg for 10 minutes) was used. The color M-mode record was used to calculate the duration of abnormal apical flow as measured from the onset of the QRS complex to the disappearance of color signals directed toward the apex. Echocardiographic images were compared at rest and during stress to identify the presence of new or worsening wall motion abnormalities (WMAs). Fourteen patients (group A) were designated as having coronary artery disease on the basis on WMAs during the stress test and abnormal coronary anatomy. Fifteen patients (group B) without WMAs in the presence of normal coronary anatomy were designated as having no coronary artery disease. All but two patients in group A had an abnormal apical filling response to dipyridamole stress (sensitivity 86%). In these patients the marked retardation of apical filling was detected during ischemia (55 +/- 18 msec versus 120 +/- 34 msec) (p <0.01). In group B there were no dynamics in apical filling (specificity 100%). Color M-mode Doppler imaging showed retarded apical filling during dipyridamole-induced myocardial ischemia. This abnormal filling pattern may be a useful adjunct to WMAs during dipyridamole stress echocardiography.

Aged↗
PubMedDate not supplied

Comparison of exercise, dipyridamole, adenosine, and dobutamine stress with the use of Tc-99m tetrofosmin tomographic imaging.

PURPOSE: The purpose of this study was to compare defect extent and severity and myocardial uptake with exercise and pharmacologic stress with technetium-99m (Tc-99m) tetrofosmin tomographic myocardial perfusion imaging. BACKGROUND: Detection of stress-induced myocardial perfusion defects depends on both a disparity in blood flow between normal and stenotic vessels and the extraction fraction and linearity of myocardial uptake of the tracer. There are limited clinical data for exercise or pharmacologic stress with Tc-99m tetrofosmin tomographic myocardial perfusion imaging. METHODS: Thirty-one patients with coronary artery disease and 7 with a < 5% likelihood of coronary artery disease underwent on separate days Tc-99m tetrofosmin single-photon emission computed tomographic imaging at rest and after exercise, dipyridamole, adenosine, and dobutamine stress. Images were interpreted by a blinded consensus of 3 experienced readers with a 17-segment model and 5-point scoring system. RESULTS: Compared with exercise, the summed stress score was smaller with dipyridamole (P < .01), and the reversibility score was smaller with both dipyridamole (P < .01) and dobutamine (P < .05), whereas the number of abnormal and reversible segments was less with both dipyridamole (P < .01 and P < .001, respectively) and dobutamine (both P < .05). No significant differences were found in the summed stress or reversibility scores and the number of abnormal or reversible segments between exercise and adenosine. CONCLUSIONS: Compared with exercise, defect extent, severity, and reversibility are less with dipyridamole and dobutamine with Tc-99m tetrofosmin single photon emission computed tomographic imaging.

Adenosine↗