European Stroke Prevention Study. 2. Dipyridamole and acetylsalicylic acid in the secondary prevention of stroke

In 1988, we undertook a randomized, placebo-controlled, double-blind trial to investigate the safety and efficacy of low-dose acetylsalicylic acid (ASA), modified-release dipyridamole, and the two agents in combination for secondary prevention of ischemic stroke. Patients with prior stroke or transient ischemic attack (TIA) were randomized to treatment with ASA alone (50 mg daily), modified-release dipyridamole alone (400 mg daily), the two agents in a combined formulation, or placebo. Primary endpoints were stroke, death, and stroke or death together. TIA and other vascular events were secondary endpoints. Patients were followed on treatment for two years. Data from 6,602 patients were analysed. Factorial analysis demonstrated a highly significant effect for ASA and for dipyridamole in reducing the risk of stroke (p < or = 0.001) and stroke or death combined (p < 0.01). In pairwise comparisons, stroke risk in comparison to placebo was reduced by 18% with ASA alone (p = 0.013); 16% with dipyridamole alone (p = 0.039); and 37% with combination therapy (p < 0.001). Risk of stroke or death was reduced by 13% with ASA alone (p = 0.016); 15% with dipyridamole alone (p = 0.015); and 24% with the combination (p < 0.001). The treatment had no statistically significant effect on the death rate alone. Factorial analysis also demonstrated a highly significant effect of ASA (p < 0.001) and dipyridamole (p < 0.01) for preventing TIA. The risk reduction for the combination was 36% (p < 0.001) in comparison with placebo. Headache was the most common adverse event, occurring more frequently in dipyridamole-treated patients. All-site bleeding and gastrointestinal bleeding were significantly more common in patients who received ASA in comparison to placebo or dipyridamole. We conclude that (1) ASA 25 mg twice daily and dipyridamole, in a modified-release form, at a dose of 200 mg twice daily have each been shown to be equally effective for the secondary prevention of ischemic stroke and TIA; (2) when co-prescribed the protective effects are additive, the combination being significantly more effective than either agent prescribed singly; (3) low-dose ASA does not eliminate the propensity for induced bleeding.

Aspirin and extended-release dipyridamole versus clopidogrel for recurrent stroke

BACKGROUND

Recurrent stroke is a frequent, disabling event after ischemic stroke. This study compared the efficacy and safety of two antiplatelet regimens--aspirin plus extended-release dipyridamole (ASA-ERDP) versus clopidogrel.

METHODS

In this double-blind, 2-by-2 factorial trial, we randomly assigned patients to receive 25 mg of aspirin plus 200 mg of extended-release dipyridamole twice daily or to receive 75 mg of clopidogrel daily. The primary outcome was first recurrence of stroke. The secondary outcome was a composite of stroke, myocardial infarction, or death from vascular causes. Sequential statistical testing of noninferiority (margin of 1.075), followed by superiority testing, was planned.

RESULTS

A total of 20,332 patients were followed for a mean of 2.5 years. Recurrent stroke occurred in 916 patients (9.0%) receiving ASA-ERDP and in 898 patients (8.8%) receiving clopidogrel (hazard ratio, 1.01; 95% confidence interval [CI], 0.92 to 1.11). The secondary outcome occurred in 1333 patients (13.1%) in each group (hazard ratio for ASA-ERDP, 0.99; 95% CI, 0.92 to 1.07). There were more major hemorrhagic events among ASA-ERDP recipients (419 [4.1%]) than among clopidogrel recipients (365 [3.6%]) (hazard ratio, 1.15; 95% CI, 1.00 to 1.32), including intracranial hemorrhage (hazard ratio, 1.42; 95% CI, 1.11 to 1.83). The net risk of recurrent stroke or major hemorrhagic event was similar in the two groups (1194 ASA-ERDP recipients [11.7%], vs. 1156 clopidogrel recipients [11.4%]; hazard ratio, 1.03; 95% CI, 0.95 to 1.11).

CONCLUSIONS

The trial did not meet the predefined criteria for noninferiority but showed similar rates of recurrent stroke with ASA-ERDP and with clopidogrel. There is no evidence that either of the two treatments was superior to the other in the prevention of recurrent stroke. (ClinicalTrials.gov number, NCT00153062.)

Aspirin plus dipyridamole versus aspirin alone after cerebral ischaemia of arterial origin (ESPRIT): randomised controlled trial

BACKGROUND

Results of trials of aspirin and dipyridamole combined versus aspirin alone for the secondary prevention of vascular events after ischaemic stroke of presumed arterial origin are inconsistent. Our aim was to resolve this uncertainty.

METHODS

We did a randomised controlled trial in which we assigned patients to aspirin (30-325 mg daily) with (n=1363) or without (n=1376) dipyridamole (200 mg twice daily) within 6 months of a transient ischaemic attack or minor stroke of presumed arterial origin. Our primary outcome event was the composite of death from all vascular causes, non-fatal stroke, non-fatal myocardial infarction, or major bleeding complication, whichever happened first. Treatment was open, but auditing of outcome events was blinded. Primary analysis was by intention to treat. This study is registered as an International Standard Randomised Controlled Trial (number ISRCTN73824458) and with (NCT00161070).

FINDINGS

Mean follow-up was 3.5 years (SD 2.0). Median aspirin dose was 75 mg in both treatment groups (range 30-325); extended-release dipyridamole was used by 83% (n=1131) of patients on the combination regimen. Primary outcome events arose in 173 (13%) patients on aspirin and dipyridamole and in 216 (16%) on aspirin alone (hazard ratio 0.80, 95% CI 0.66-0.98; absolute risk reduction 1.0% per year, 95% CI 0.1-1.8). Addition of the ESPRIT data to the meta-analysis of previous trials resulted in an overall risk ratio for the composite of vascular death, stroke, or myocardial infarction of 0.82 (95% CI 0.74-0.91). Patients on aspirin and dipyridamole discontinued trial medication more often than those on aspirin alone (470 vs 184), mainly because of headache.

INTERPRETATION

The ESPRIT results, combined with the results of previous trials, provide sufficient evidence to prefer the combination regimen of aspirin plus dipyridamole over aspirin alone as antithrombotic therapy after cerebral ischaemia of arterial origin.

"AICLA" controlled trial of aspirin and dipyridamole in the secondary prevention of athero-thrombotic cerebral ischemia

604 Patients with atherothrombotic cerebral ischemic events (transient, 16%: or completed, 84%) referrable either to the carotid or to the vertebral-basilar circulation were entered into a double blind randomized clinical trial (AICLA) to determine whether aspirin (A) (1 g/day) or aspirin (1 g/day) + Dipyridamole (225 mg/day) (AD) would produce a significant reduction in the subsequent (3 years) occurrence of fatal and nonfatal cerebral infarction. Randomization produced remarkably comparable treatment groups and this good comparability was maintained throughout the study. Adherence to the protocol and drug compliance were excellent. Side effects, particularly symptoms of peptic ulcer and hemorrhagic events were significantly (p less than 0.03) more frequent in the two treatment groups containing aspirin. With the exception of patients who withdrew from the study, each patient was followed for 3 years. At the end of the study, the number of fatal and nonfatal cerebral infarctions was 31 in the placebo (P) group, 17 in the A group and 18 in the AD group. Taking into account the duration of follow-up for each patient, these figures correspond to cumulative rates of 18% in the P group and 10.5% in each of the 2 active treatment groups. Analysis with the Mantel Method showed: 1)--A difference at the 6% level between the 3 groups and between P and AD; 2)--A difference at the 5% level between P and A; 3)--No difference between (A and AD; 4)--A difference at the 2% level between the P group and the two treated groups taken together (A + AD). Among other diseases occurring during the trial, the only significant difference concerned myocardial infarction, which was less frequent in the 2 treated groups (P less than 0.05). Subgroup analysis failed to show a significant sex difference in the efficacy of aspirin. It is concluded that, in patients comparable to those defined in the protocol, Aspirin (1 g) has a significantly beneficial effect in the secondary prevention of atherothrombotic cerebral infarction.

Persantine and aspirin in coronary heart disease. The Persantine-Aspirin Reinfarction Study Research Group

In the Persantine-Aspirin Reinfarction Study (PARIS) trial, 2026 persons who had recovered from myocardial infarction (MI) were randomized into three groups: Persantine plus aspirin (PR/A) (n = 810); aspirin alone (ASA) (n = 810); placebo (PLBO) (n = 406). The average length of follow-up study was 41 months. Results for the three specified primary end points were: total mortality 16% lower in PR/A and 18% lower in ASA compared with PLBO; coronary mortality 24% and 21% lower; incidence of nonfatal MI plus fatal coronary disease 25% and 24% lower. These differences were not satistically significant by the study criterion (Z greater than or equal to 2.6). By life-table analysis, the rates of coronary mortality and coronary incidence were about 50% lower in the PR/A group than in the PLBO group from 8-24 months, and for coronary incidence all Z values were greater than or equal to 2.6; ASA rates were about 30% lower than PLBO rates, and for coronary incidence, Z values were greater than or equal to 2.6 at two points. For these end points, from 8-20 months, PR/A rates were about 30% lower than ASA rates, but all Z values were less than 2.0 PR/A and ASA patients entering within 6 months of last MI showed the largest percentage reductions in mortality; only the difference between PR/A and PLBO groups for 3-year coronary mortality yielded a Z value of 2.6.

Serial thallium-201 myocardial imaging after dipyridamole infusion: diagnostic utility in detecting coronary stenoses and relationship to regional wall motion

After a 4-minute i.v. dipyridamole infusion, 0.14 mg/kg/min, serial thallium-201 scans were obtained in 60 patients undergoing cardiac catheterization. Forty patients had significant (greater than or equal to 50% stenosis) coronary artery disease (CAD), and 20 patients had normal coronary arteries or trivial lesions. The images were graded qualitatively for thallium activity by three observers. Sensitivity was 93% (37 of 40) and specificity was 80% (16 of 20). The sensitivity and specificity of the thallium-201 study were not affected by the extent of CAD, the presence of Q waves, or propranolol therapy. Twenty-seven of 37 patients who had initial defects (73%) had complete thallium redistribution of one or more defects. Patient-by-patient analysis using a regression model of all patients showed that the fate of a segmental thallium defect predicted abnormal wall motion by angiography better than ECG Q waves. The presence of propranolol therapy or collaterals did not significantly affect the thallium redistribution results. We conclude that qualitative interpretation by multiple observers of thallium images after dipyridamole infusion is a highly sensitive and specific test for CAD. After dipyridamole, as with exercise stress, the extent of thallium redistribution is related to the degree of myocardial wall motion abnormality.

Effect of dipyridamole plus aspirin on hemodialysis graft patency

BACKGROUND

Arteriovenous graft stenosis leading to thrombosis is a major cause of complications in patients undergoing hemodialysis. Procedural interventions may restore patency but are costly. Although there is no proven pharmacologic therapy, dipyridamole may be promising because of its known vascular antiproliferative activity.

METHODS

We conducted a randomized, double-blind, placebo-controlled trial of extended-release dipyridamole, at a dose of 200 mg, and aspirin, at a dose of 25 mg, given twice daily after the placement of a new arteriovenous graft until the primary outcome, loss of primary unassisted patency (i.e., patency without thrombosis or requirement for intervention), was reached. Secondary outcomes were cumulative graft failure and death. Primary and secondary outcomes were analyzed with the use of a Cox proportional-hazards regression with adjustment for prespecified covariates.

RESULTS

At 13 centers in the United States, 649 patients were randomly assigned to receive dipyridamole plus aspirin (321 patients) or placebo (328 patients) over a period of 4.5 years, with 6 additional months of follow-up. The incidence of primary unassisted patency at 1 year was 23% (95% confidence interval [CI], 18 to 28) in the placebo group and 28% (95% CI, 23 to 34) in the dipyridamole-aspirin group, an absolute difference of 5 percentage points. Treatment with dipyridamole plus aspirin significantly prolonged the duration of primary unassisted patency (hazard ratio, 0.82; 95% CI, 0.68 to 0.98; P=0.03) and inhibited stenosis. The incidences of cumulative graft failure, death, the composite of graft failure or death, and serious adverse events (including bleeding) did not differ significantly between study groups.

CONCLUSIONS

Treatment with dipyridamole plus aspirin had a significant but modest effect in reducing the risk of stenosis and improving the duration of primary unassisted patency of newly created grafts. (ClinicalTrials.gov number, NCT00067119.)

The safety of intravenous dipyridamole thallium myocardial perfusion imaging. Intravenous Dipyridamole Thallium Imaging Study Group

Clinical data on 3,911 patients were collected from 64 individual investigators to evaluate the safety of intravenous dipyridamole-thallium imaging as an alternative to exercise thallium imaging for the evaluation of coronary artery disease. There were two deaths because of myocardial infarctions, two nonfatal myocardial infarctions, and six cases of acute bronchospasm. Chest pain occurred in 770 patients (19.7%). Headache and dizziness were reported by 476 patients (12.2%) and 460 patients (11.8%), respectively. ST-T changes on the electrocardiogram were seen in 292 patients (7.5%). Use of parenteral aminophylline to treat adverse events associated with intravenous dipyridamole brought complete relief of symptoms in 439 of 454 patients (96.7%). There is a potential for increased risk for serious ischemic events in patients with a history of unstable angina who are administered intravenous dipyridamole. In patients with acutely unstable angina (i.e., continuing chest pain) or in the acute phase of myocardial infarction, use of intravenous dipyridamole in thallium scintigraphy should be avoided. There is also an increased risk for bronchospasm in patients with a history of asthma; acute bronchospasm can be relieved immediately by administration of aminophylline. These results demonstrate that intravenous dipyridamole-thallium scintigraphy is a relatively safe, noninvasive technique for the evaluation of coronary artery disease.

Dipyridamole-echocardiography test in effort angina pectoris

This study assesses the clinical feasibility and usefulness of dipyridamole infusion for the detection of coronary artery disease (CAD) by using 2-dimensional echocardiography (2-D echo) and 12-lead electrocardiographic monitoring. Dipyridamole infusion (0.14 mg/kg/min for 4 minutes) was performed in 66 consecutive patients with effort chest pain and in 9 control subjects. Among the 28 patients with positive dipyridamole-echocardiography test responses, 18 had diagnostic electrocardiographic changes (ST-segment depression on anterolateral leads), but these changes were unrelated to the site of asynergy. The dipyridamole-echocardiography test had an overall sensitivity of 56% and specificity of 100% for the presence of CAD. Exercise stress testing (EST) had an overall sensitivity of 62% and a specificity of 80%. Thus, the dipyridamole-echocardiography test, which is feasible in essentially all patients with good basal echocardiograms, has a lower overall sensitivity in detecting CAD than EST but a higher specificity, detects the site of apparent ischemia as identified by regional asynergy more precisely than EST, and can unmask electrocardiographically silent effort ischemia.

Controlled trial of dipyridamole in cerebral vascular disease

A controlled double-blind study of the effect of dipyridamole was performed in 169 patients with established cerebral vascular disease. A dose of 400 mg. was used initially, given daily for an average of 14 months; the dose was then increased to 800 mg. daily for a further average period of 11 months. When the incidence of cerebral ischaemic episodes during treatment was compared in the drug-treated and placebo-treated groups no significant difference was found.

Dipyridamole-echocardiography test: historical background and physiologic basis

Dipyridamole was first introduced as an antianginal, coronary vasodilator agent. It was soon found that this drug could not prevent effort ischaemia; on the contrary, given intravenously, it could frequently induce ischaemia in the presence of coronary artery stenosis. This property was exploited for the diagnosis of coronary artery disease. The dipyridamole-induced ischaemia was detected by different techniques: ST-segment depression, thallium 201 scintigraphy and echocardiography. This review article describes the mechanisms underlying dipyridamole-induced ischaemia and discusses the value of this pharmacologic stress test for the detection of coronary artery disease.

Comparison of adenosine, dipyridamole, and dobutamine in stress echocardiography

OBJECTIVE

To compare adenosine, dipyridamole, and dobutamine in stress echocardiography with regard to sensitivity, specificity, accuracy, and side effects.

DESIGN

Crossover, blinded comparison, with coronary angiography serving as the criterion standard.

SETTING

U.S. Army tertiary care hospital.

PARTICIPANTS

Forty participants, 25 with coronary disease and 15 without coronary disease. Patients were eligible if they had coronary angiography within 6 weeks of stress testing or if they had a risk for coronary disease of less than 5%.

MEASUREMENTS

Left ventricular wall motion was recorded after dobutamine (0.38 mg/kg body weight), adenosine (0.84 mg/kg body weight), and dipyridamole (0.84 mg/kg body weight) stress testing. Stress echocardiographic evaluation was considered to be abnormal if the patient developed new or progressive wall motion abnormalities. The rate of side effects for the types of echocardiography and the patient preference were recorded.

MAIN RESULTS

The sensitivity of dobutamine stress echocardiography (76%; 95% CI, 59% to 93%) was significantly higher than that of adenosine echocardiography (40%; CI, 21% to 59%; P less than 0.001) and that of dipyridamole echocardiography (56%; CI, 37% to 75%; P = 0.019). The specificity of adenosine testing (93%; CI, 80% to 100%) was significantly higher than that of dobutamine echocardiography (60%; CI, 35% to 85%; P = 0.008) and that of dipyridamole echocardiography (67%; CI, 43% to 91%; P = 0.028). Symptoms were more frequent with adenosine echocardiography (100%) than with dipyridamole (88%; P less than 0.001) or dobutamine (80%; P less than 0.001) echocardiography. Treatment for persistent symptoms was required in more patients after dipyridamole echocardiography (40%) than after dobutamine (12%; P less than 0.001) or adenosine (0%; P less than 0.001) echocardiography. More patients preferred dobutamine (48%) or dipyridamole (40%) echocardiography to adenosine echocardiography (12%; P less than 0.001).

CONCLUSIONS

Dobutamine stress echocardiography is more sensitive and is better tolerated than adenosine or dipyridamole stress echocardiography. Adenosine echocardiography is more specific than dobutamine or dipyridamole echocardiography and is less likely to cause persistent symptoms.

Anti-platelet therapy in graft thrombosis: results of a prospective, randomized, double-blind study

Hemodialysis (HD) vascular access thrombosis remains a major cause of morbidity, accounting for 17.4% of all HD patient hospital admissions in 1986. We initiated this prospective, randomized, double-blind, placebo-controlled, parallel group study to examine if dipyridamole and/or aspirin decreased the rate of thrombosis of expanded polytetrafluoroethylene (ePTFE) grafts in HD patients. Two patient groups were studied: Type I--with a new ePTFE graft; and Type II--with thrombectomy and/or revision of a previously placed ePTFE graft. One hundred and seven patients were followed for 18 months or until the first thrombotic episode. Actuarial analysis of Type I patients showed cumulative thrombosis rates (mean +/- SEM) of 21 +/- 9% on dipyridamole alone, compared with 25 +/- 11% on dipyridamole and aspirin combination, 42 +/- 13% on placebo, and 80 +/- 12% on aspirin alone. The relative risk of thrombosis with dipyridamole was 0.35 (P = 0.02) and that for aspirin was 1.99 (P = 0.18). In Type II patients, the rate of thrombosis was high in all study drug and placebo groups (overall 78% thrombosis) and actuarial analysis was not carried out because of the small number of patients enrolled. We conclude that dipyridamole is beneficial in patients with new ePTFE grafts and that aspirin does not improve the risk of thrombosis in ePTFE grafts. Neither dipyridamole nor aspirin has any beneficial effect in patients with prior thrombosis of ePTFE grafts.

Safety of intravenous high-dose dipyridamole echocardiography. The Echo-Persantine International Cooperative Study Group

Clinical data on 10,451 high-dose (up to 0.84 mg/kg over 10 minutes) dipyridamole-echocardiography tests (DET) performed in 9,122 patients were prospectively collected from 33 echocardiographic laboratories, each contributing greater than 100 tests. All patients were studied for documented or suspected coronary artery disease (1,117 early [less than 18 days] after acute myocardial infarction and 293 had unstable angina). Significant side effects including major adverse reactions and minor but limiting side effects occurred in 113 patients (1.2%). Major adverse reactions occurred in 7 cases (0.07%). In 6 of these cases, adverse reactions were associated with echocardiographically assessed ischemia and included 1 prolonged cardiac asystole (complicated by acute myocardial infarction and coma, with death after 23 days), 1 short-lasting cardiac asystole, 2 myocardial infarctions, 1 pulmonary edema and 1 sustained ventricular tachycardia. In all 6 cases, the cardiologist-echocardiographer performing the study had a limited experience (less than 100 tests) with DET, and at off-line reading in 5 cases, the obvious echo-positivity preceded the onset of complications by 1 to 5 minutes. The only ischemia-independent major side effect was a short-lasting cardiac asystole that was reversed by aminophylline and atropine. Significant side effects associated with echocardiographically assessed ischemia occurred in 89 additional cases (21 with and 68 without concomitant echocardiographically assessed myocardial ischemia). The most frequent of these side effects was hypotension or bradycardia, or both, which occurred in 40 patients with negative and 6 with positive DET. In all cases, side effects promptly subsided after aminophylline. In 1,857 cases, the high dose was not given for echo-positivity before the eighth minute.(ABSTRACT TRUNCATED AT 250 WORDS)

Antiplatelet therapy with aspirin, clopidogrel, and dipyridamole versus clopidogrel alone or aspirin and dipyridamole in patients with acute cerebral ischaemia (TARDIS): a randomised, open-label, phase 3 superiority trial

BACKGROUND

Intensive antiplatelet therapy with three agents might be more effective than guideline treatment for preventing recurrent events in patients with acute cerebral ischaemia. We aimed to compare the safety and efficacy of intensive antiplatelet therapy (combined aspirin, clopidogrel, and dipyridamole) with that of guideline-based antiplatelet therapy.

METHODS

We did an international, prospective, randomised, open-label, blinded-endpoint trial in adult participants with ischaemic stroke or transient ischaemic attack (TIA) within 48 h of onset. Participants were assigned in a 1:1 ratio using computer randomisation to receive loading doses and then 30 days of intensive antiplatelet therapy (combined aspirin 75 mg, clopidogrel 75 mg, and dipyridamole 200 mg twice daily) or guideline-based therapy (comprising either clopidogrel alone or combined aspirin and dipyridamole). Randomisation was stratified by country and index event, and minimised with prognostic baseline factors, medication use, time to randomisation, stroke-related factors, and thrombolysis. The ordinal primary outcome was the combined incidence and severity of any recurrent stroke (ischaemic or haemorrhagic; assessed using the modified Rankin Scale) or TIA within 90 days, as assessed by central telephone follow-up with masking to treatment assignment, and analysed by intention to treat. This trial is registered with the ISRCTN registry, number ISRCTN47823388.

FINDINGS

3096 participants (1556 in the intensive antiplatelet therapy group, 1540 in the guideline antiplatelet therapy group) were recruited from 106 hospitals in four countries between April 7, 2009, and March 18, 2016. The trial was stopped early on the recommendation of the data monitoring committee. The incidence and severity of recurrent stroke or TIA did not differ between intensive and guideline therapy (93 [6%] participants vs 105 [7%]; adjusted common odds ratio [cOR] 0·90, 95% CI 0·67-1·20, p=0·47). By contrast, intensive antiplatelet therapy was associated with more, and more severe, bleeding (adjusted cOR 2·54, 95% CI 2·05-3·16, p<0·0001).

INTERPRETATION

Among patients with recent cerebral ischaemia, intensive antiplatelet therapy did not reduce the incidence and severity of recurrent stroke or TIA, but did significantly increase the risk of major bleeding. Triple antiplatelet therapy should not be used in routine clinical practice.

FUNDING

National Institutes of Health Research Health Technology Assessment Programme, British Heart Foundation.

Rationale, design and baseline data of a randomized, double-blind, controlled trial comparing two antithrombotic regimens (a fixed-dose combination of extended-release dipyridamole plus ASA with clopidogrel) and telmisartan versus placebo in patients with strokes: the Prevention Regimen for Effectively Avoiding Second Strokes Trial (PRoFESS)

BACKGROUND

Individuals with transient ischemic attack and ischemic stroke have a high risk of recurrent stroke and death. While acetylsalicylic acid (ASA, aspirin) is proven and accepted as standard therapy in these patients, recent trials demonstrate that a combination of ASA and dipyridamole (DP) or clopidogrel may be superior to ASA. Blocking the renin-angiotensin system with angiotensin-converting enzyme inhibitors or angiotensin receptor blockers may also reduce recurrent stroke. The ongoing PRoFESS (Prevention Regimen for Effectively Avoiding Second Strokes) trial is designed to evaluate whether ASA + extended-release DP compared to clopidogrel, and whether telmisartan in addition to usual care in individuals after a stroke, will reduce the risk of further strokes.

METHODS

PRoFESS is a multicenter, randomized, double-blind trial involving 695 sites from 35 countries or regions. Patients > or = 50 years presenting with an ischemic stroke < 120 days who were stable were randomized. The primary outcome for the trial is recurrent stroke, using a time-to-event analysis. The most important secondary outcome is the composite of stroke, myocardial infarction or vascular death. Other secondary outcomes include this composite + congestive heart failure, new-onset diabetes, other designated occlusive vascular events (pulmonary embolism, deep-vein thrombosis, peripheral arterial occlusion, transient ischemic attack, cerebral venous thrombosis or retinal vascular accident not classified as stroke), any death, stroke subtype by TOAST criteria and Mini Mental State Examination score. Safety is evaluated by assessing the risk of major hemorrhagic events. The comparison between ASA + DP and clopidogrel is based on an initial assessment of noninferiority, followed by evaluation of superiority, while for telmisartan, we will assess its superiority over placebo.

RESULTS

With over 20,000 patients randomized, and utilizing a 2 x 2 factorial design, PRoFESS is the largest stroke trial to investigate the prevention of recurrent stroke. The mean age was 66.1 +/- 8.6 years, and 36.0% of the patients were females. The median time from qualifying event to randomization was 15 days with 39.9% of patients randomized within 10 days. According to the TOAST criteria, 28.5% of the strokes were due to large-vessel disease, 52.1% to small-vessel disease, 1.8% to cardioembolism, and 2.0% to other determined etiologies and 15.5% were of undetermined etiology.

CONCLUSIONS

PRoFESS is the largest secondary stroke prevention trial to date and will directly compare two antiplatelet regimens as well as the benefit of telmisartan versus placebo.

Safety of dipyridamole testing in 73,806 patients: the Multicenter Dipyridamole Safety Study

BACKGROUND

Dipyridamole imaging is widely used as an alternative to exercise testing to identify and risk stratify patients with coronary artery disease. Safety data on intravenous dipyridamole stress testing has been derived largely from individual institutional data.

METHODS AND RESULTS

Data were collected retrospectively by 85 coinvestigators from 73,806 patients who underwent intravenous dipyridamole stress imaging in 59 hospitals and 19 countries to determine the incidence of major adverse reactions during testing. The dose of dipyridamole infused was 0.56 mg/kg in 64,740 patients, 0.74 mg/kg in 6551 patients, and 0.84 mg/kg in 2515 patients. Combined major adverse events among the entire 73,806 patients included seven cardiac deaths (0.95 per 10,000), 13 nonfatal myocardial infarctions (1.76 per 10,000), six nonfatal sustained ventricular arrhythmias (0.81 per 10,000) (ventricular tachycardia in two and ventricular fibrillation in four), nine transient cerebral ischemic attacks (1.22 per 10,000), (with speech or motor deficit), one stroke, and nine severe bronchospasms (1.22 per 10,000) (one intubation and eight near intubations). In addition to the safety data, detailed demographic, peripheral hemodynamic, side effect, and concomitant drug data were examined in a subgroup of 3751 patients. End points from subsets of patients were compared with those of the group as a whole. Multivariate analysis revealed that dipyridamole-induced chest pain was more common in patients less than 70 years old (p = 0.0017), those with a history of coronary revascularization (p = 0.002), or patients taking aspirin (p = 0.0001). Minor noncardiac side effects were less frequent among the elderly (p = 0.0053) and more frequent in women (p = 0.0001) and patients taking maintenance aspirin (p = 0.0034). When a patient was judged on the basis of the adequacy of hemodynamic response to be a dipyridamole "nonresponder" (< 10 mm Hg drop in systolic blood pressure and 10 beats/min increase in heart rate), the only significant predictor was angiotensin-converting enzyme inhibitor intake (p = 0.0025). Inferoposterior hypoperfusion was significantly more frequent in patients with dipyridamole-induced hypotension: 57% (44/77) (p < 0.0001) of those who had hypotension and 89% (8/9) (p = 0.0076) who had severe symptomatic bradyarrhythmias displayed inferoposterior defects on thallium scanning. Caffeine levels were determined in 391 consecutive patients: levels greater than 5 mg/L were observed in only eight patients (2%), suggesting that methylxanthine levels sufficient to alter the hemodynamic response to dipyridamole resulting in suboptimal hyperemic stress are unlikely when patients take nothing by mouth after midnight.

CONCLUSION

The risk of serious dipyridamole-induced side effects is very low and is comparable to that reported for exercise testing in a similar patient population.

The atropine factor in pharmacologic stress echocardiography. Echo Persantine (EPIC) and Echo Dobutamine International Cooperative (EDIC) Study Groups

OBJECTIVES

This study sought to compare, head to head, the two most popular pharmacologic stress echocardiographic tests--dipyridamole and dobutamine--with state of the art protocols in a large multicenter prospective study.

BACKGROUND

In the continuing quest for ideal diagnostic accuracy, pharmacologic stress echocardiography has quickly moved over the years from low to high dose regimens and is currently performed with atropine coadministration.

METHODS

Dobutamine (up to 40 microgram/kg body weight per min) plus atropine (up to 1 mg over 4 h) and dipyridamole (up to 0.84 mg/kg per min over 10 h) plus atropine (up to 1 mg over 4 h) stress echocardiography was performed on different days, in random order and within 1 week in 360 patients with chest pain syndrome. Thirteen different echocardiographic laboratories, all fulfilling quality control criteria for stress echocardiographic reading, contributed to the study.

RESULTS

No major complications occurred during either test. The test was interrupted before achievement of predetermined end points for limiting side effects in 37 dobutamine-atropine and 7 dipyridamole-atropine stress echocardiographic studies (feasibility 90% vs. 98%, p < 0.01). Diagnostic accuracy was assessed in a subset of 110 patients with no obvious rest dyssynergy (akinesia or dyskinesia) who underwent coronary angiography independently of test results and within 1 week of testing. Significant coronary artery disease (> or = 50% diameter reduction in at least one major coronary vessel by quantitative coronary angiography) was found in 92 patients. Sensitivity for detection of coronary artery disease was 84% (77 of 92) for dobutamine-atropine and 82% (75 of 92) for dipyridamole-atropine stress echocardiography (p = NS), with a specificity of 89% (16 of 18) for dobutamine-atropine and 94% (17 of 18) for dipyridamole-atropine stress echocardiography (p = NS). A significant correlation was present between peak wall motion score index during dipyridamole-atropine and dobutamine-atropine stress echocardiography (r = 0.83, p < 0.0001).

CONCLUSIONS

Dobutamine-atropine and dipyridamole-atropine stress echocardiography are safe and feasible, although submaximal studies are more frequent with dobutamine. The two stresses have comparable accuracy in the detection of angiographically assessed coronary artery disease, although dobutamine is marginally more sensitive and dipyridamole marginally more specific. Stratification of the ischemic response in the space domain is also comparable with the two stresses.

Safety of intravenous dipyridamole for stress testing with thallium imaging

Cardiac and noncardiac side effects were studied in 293 consecutive patients referred for nonexercise stress thallium imaging with intravenous dipyridamole. Six minutes after the initiation of infusion, there was a mean 9-beat/min increase in heart rate and a mean 12-mm Hg decrease in systolic blood pressure. The largest increase in heart rate exceeded 20 beats/min in only 13% of patients and the largest decrease in systolic blood pressure exceeded 20 mm Hg in 31%. Noncardiac side effects were headache (11%), lightheadedness or dizziness (5%) and nausea (4%). Only 9 patients required intravenous aminophylline for relief of noncardiac side effects: severe headache in 7 and nausea in 2. Cardiac side effects included chest pain in 76 patients (26%), of whom 70% were given aminophylline for relief of symptoms. Sixty patients (20%) had ischemic ST-segment depression and 56 (19%) had arrhythmias (ventricular in 50 and atrial in 6). There were no deaths, myocardial infarctions or sustained arrhythmias due to dipyridamole administration. Among 62 patients also undergoing cardiac catheterization, side effects except for arrhythmias were unrelated to the number of vessels with coronary artery disease. Intravenous dipyridamole is safe for nonexercise stress testing and has few serious side effects. However, the possibility of ischemia requires careful selection of patients and monitoring of vital signs and the electrocardiogram during the test.

Stress echocardiography: comparison of exercise, dipyridamole and dobutamine in detecting and predicting the extent of coronary artery disease

OBJECTIVES

This study was designed to compare exercise, dipyridamole and dobutamine echocardiography in the same patients and to evaluate, by measuring physiologic and echocardiographic variables, the mechanisms by which exercise and dobutamine induce ischemia.

BACKGROUND

The diagnostic value of stress echocardiography has been widely reported, but the specific effects of exercise, dipyridamole and dobutamine have not been directly compared. Furthermore, no echocardiography study has evaluated left ventricular volume changes at ischemic threshold during exercise and dobutamine administration.

METHODS

One hundred patients with suspected (Group A, n = 60) or known (Group B, n = 40) coronary artery disease underwent all three tests in random order.

RESULTS

In Group A, the sensitivities of exercise (mean 76%, 95% confidence interval [CI] 58% to 94%) and of dobutamine echocardiography (72%, 95% CI 53% to 91%) were higher than that of dipyridamole (52%, 95% CI 31% to 73%; p = 0.01 and p = 0.02, respectively). Specificity did not differ significantly among tests (94% for exercise [95% CI 86% to 100%] and 97% for dipyridamole and dobutamine [95% CI 91% to 100%]). Accuracy was identical for exercise and dobutamine (87%) and higher than that for dipyridamole (78%, p = 0.06). In Group B, the accuracy in predicting coronary disease extent was 71% for exercise, 33% for dipyridamole and 75% for dobutamine. At ischemic threshold, end-systolic volume index and the ratio of systolic blood pressure to end-systolic volume, a variable related to myocardial contractility, were significantly lower and higher, respectively, with dobutamine than during exercise (p < 0.05).

CONCLUSIONS

In a clinical setting, exercise echocardiography should represent the first diagnostic approach because it has high diagnostic efficacy and provides additional information on exercise capacity; pharmacologic stress, particularly that of dobutamine, provides a pivotal diagnostic tool when exercise is not feasible or its results are nondiagnostic. Our preliminary data on echocardiographic evaluation at ischemic threshold support the view that myocardial contractility is a major factor in inducing ischemia during dobutamine infusion.

Comparison of dobutamine stress echocardiography, dipyridamole stress echocardiography and exercise stress testing for diagnosis of coronary artery disease

To compare the value of dobutamine and dipyridamole stress echocardiography with exercise stress testing for the diagnosis of coronary artery disease (CAD), 80 patients with chest pain of suspected myocardial ischemic origin (57 with CAD and 23 without significant CAD) underwent dobutamine stress echocardiography (5 to 40 micrograms/kg/min), dipyridamole echocardiography (0.84 mg/kg over 10 minutes) and bicycle exercise electrocardiography after discontinuation of antianginal treatment. Dobutamine echocardiography and exercise testing revealed a higher overall sensitivity than dipyridamole echocardiography (79 vs 60%, p < 0.005; 77 vs 60%, p < 0.05, respectively); this finding was due to a higher dobutamine and exercise sensitivity in 1-vessel CAD (62 vs 33%, p < 0.05 for both tests), whereas sensitivity of the 3 tests was similar in multivessel CAD. Dobutamine and dipyridamole showed a higher specificity than exercise (83 vs 43%, p < 0.01; 96 vs 43%, p < 0.005, respectively). Diagnostic accuracy of dobutamine echocardiography was higher than that of exercise (80 vs 67%, p < 0.05), whereas the difference with dipyridamole (80 vs 70%) was not significant. In the tests that yielded positive results, double product during exercise was significantly higher than that during dobutamine and dipyridamole echocardiography. No major complications occurred during the tests, but adverse effects were more frequent during dobutamine testing. Thus, dobutamine echocardiography may be superior to dipyridamole echocardiography and exercise electrocardiography for the diagnosis of CAD.