Combined therapy of hypertensive nephropathy with ginkgo leaf extract and dipyridamole injection and antihypertensive drugs: A systematic review and meta-analysis

BACKGROUND

In recent years, the incidence rate of hypertensive nephropathy has been increasing quickly, which has been a major threat to people's health. Renin-angiotensin-aldosterone system blockers have certain curative effects. However, there are some patients having serious adverse reactions, and the benefit population is limited, so the treatment of hypertensive renal damage is necessary to have beneficial supplement. More and more clinical studies have shown that ginkgo leaf extract and dipyridamole injection (GDI) combined with antihypertensive drugs has achieved good results in the treatment of hypertensive renal damage. It is supposed to be a supplementary treatment in hypertensive nephropathy.

OBJECTIVES

To systematically assess the efficacy and safety of GDI combined with antihypertensive drugs on hypertensive renal injury.

METHODS

Seven databases including PubMed, Cochrane Library, Embase, Wanfang database, China biomedical literature service system (Sino Med), VIP Chinese Sci-tech journal database (VIP), and China national knowledge internet (CNKI) were retrieved to collect randomized controlled trials (RCTs) in the experimental group containing combined therapy of hypertensive nephropathy with GDI and antihypertensive drugs. The retrieval time was from the establishment of database to July 8, 2020. Two researchers independently selected literature, extracted data, and evaluated the risk of bias in the study. The methodological quality was evaluated with Cochrane handbook and meta-analysis was performed with Stata 14.0 software.

RESULTS

Eight studies were included in this study which involved 556 patients. The meta-analyses indicated that, compared with using antihypertensive drugs alone, combined treatment of GDI with antihypertensive drugs can decrease 24-hour urinary total protein (weighted mean difference [WMD] -0.61, 95% confidence interval [CI]: -0.82, -0.39; k = 6, P ≤ .001), blood urea nitrogen (WMD -1.27, 95% CI: -2.45, -0.10; k = 6, P = .033, serum creatinine (WMD -29.50, 95% CI: -56.44, -2.56; number of estimates [k] = 6, P = .032).

CONCLUSIONS

Our meta-analyses showed that GDI combined with antihypertensive drugs can improve the renal function of hypertensive patients with renal injury.

Long-term prognostic value of stress perfusion cardiovascular magnetic resonance in patients without known coronary artery disease

BACKGROUND

To assess the incremental long-term prognostic value of vasodilator stress perfusion cardiovascular magnetic resonance (CMR) in patients without known coronary artery disease (CAD).

METHODS

Between 2010 and 2011, consecutive patients with cardiovascular risk factors without known CAD referred for stress CMR were followed for the occurrence of major adverse cardiac events (MACE), defined by cardiovascular mortality or recurrent non-fatal myocardial infarction (MI). Uni- and multivariable Cox regressions were performed to determine the prognostic value of ischemia and unrecognized MI defined by sub-endocardial or transmural late gadolinium enhancement (LGE).

RESULTS

Among 2,295 patients without known CAD, 2058 (89.7%) (71.2 ± 12.5 years; 37.5% males) completed the follow-up (median [IQR]: 8.3 [7.3-8.7] years), and 203 had MACE (9.9%). Using Kaplan-Meier analysis, ischemia and unrecognized MI were associated with MACE (hazard ratio, HR: 4.64 95% CI: 3.69-6.17 and HR: 2.88; 95% CI: 2.08-3.99, respectively; both p < 0.001). In multivariable stepwise Cox regression, ischemia and unrecognized MI were independent predictors of MACE (HR = 3.71; 95% CI 2.73-5.05, p < 0.001 and HR = 1.73; 95% CI 1.22-2.45, p = 0.002; respectively) and cardiovascular mortality (HR: 3.13; 95% CI: 2.17-4.51, p < 0.001 and HR = 1.73; 95% CI 1.15-2.62, p = 0.009; respectively). The addition of ischemia and unrecognized MI led to an improved model discrimination for MACE (change in C statistic from 0.61 to 0.72; NRI = 0.431; IDI = 0.053).

CONCLUSIONS

Inducible ischemia and unrecognized MI identified by stress CMR have incremental long term prognostic value for the incidence of MACE in patients without known CAD over traditional risk factors and left ventricular ejection fraction.

Prognostic value of stress cardiovascular magnetic resonance in asymptomatic patients with known coronary artery disease

BACKGROUND

Several studies have established the prognostic value of vasodilator stress cardiovascular magnetic resonance (CMR) in broad population of patients with suspected or known coronary artery disease (CAD), but this specific population of asymptomatic patients with known CAD have never been formally evaluated. To assess the long-term prognostic value of vasodilator stress perfusion CMR in asymptomatic patients with obstructive CAD.

METHODS

Between 2009 and 2011, consecutive asymptomatic patients with obstructive CAD referred for vasodilator stress CMR were followed for the occurrence of major adverse cardiovascular events (MACE), defined by cardiovascular mortality or recurrent non-fatal myocardial infarction (MI). Uni- and multivariable Cox regressions were performed to determine the prognostic value of myocardial ischemia and myocardial infarction defined by late gadolinium enhancement (LGE) with ischemic pattern.

RESULTS

Among 1529 asymptomatic patients with obstructive CAD, 1342 (87.8%; 67.7 ± 10.5 years, 82.0% males) completed the follow-up (median 8.3 years), and 195 had MACE (14.5%). Patients without stress-induced myocardial ischemia had a low annualized rate of MACE (2.4%), whereas the annualized rate of MACE was higher for patients with mild, moderate, or severe ischemia (7.3%, 16.8%, and 42.2%, respectively; ptrend < 0.001). Using Kaplan-Meier analysis, myocardial ischemia and LGE were associated with MACE (hazard ratio, HR 2.52; 95% CI 1.90-3.34 and HR 2.04; 95% CI 1.38-3.03, respectively; both p < 0.001). In multivariable stepwise Cox regression, myocardial ischemia and LGE were independent predictors of MACE (HR 2.80 95% CI 2.10-3.73, p < 0.001 and HR 1.51; 95% CI 1.01-2.27, p = 0.045; respectively). The addition of myocardial ischemia and LGE led to improved model discrimination for MACE (change in C statistic from 0.61 to 0.68; NRI = 0.207; IDI = 0.021).

CONCLUSIONS

Vasodilator stress CMR-induced myocardial ischemia and LGE are good long-term predictors for the incidence of MACE in asymptomatic patients with obstructive CAD.

Comparison of two dipyridamole infusion protocols for myocardial perfusion imaging in subjects with low likelihood of significant obstructive coronary artery disease

BACKGROUND

Myocardial perfusion imaging (MPI) with positron emission tomography allows accurate measurements of myocardial blood flow (MBF). Stress MBF thresholds have been proposed to provide diagnostic and prognostic information in different pathology. Most studies relying on dipyridamole use a 5-minute infusion protocol, while current guidelines recommend a 4-minute infusion. The purpose of this study is to compare the effects of different dipyridamole infusion times on stress MBF.

METHODS

The charts of 2,207 patients who underwent rubidium-82 MPI were retrospectively reviewed and 147 subjects with low likelihood of significant coronary artery disease (CAD) defined as calcium score = 0, body mass index < 45 kg·m-2, and summed stress score ≤ 3 were included. Of those, 65 were imaged with a 4-minute dipyridamole infusion (0.56 mg·kg-1) protocol and 82 with a 5-minute protocol (0.70 mg·kg-1).

RESULTS

Stress MBF (3.23±0.76 vs 3.02±0.71 mL·min-1·g-1, P = 0.09), myocardial flow reserve (2.70±0.67 vs 2.85±0.74, P = 0.20), and coronary vascular resistance index (30±10 vs 31±9 mmHg × g × min·mL-1, P = 0.38) were not significantly different between the two protocols. The 5-minute protocol was associated with higher prevalence of symptoms (92.7% vs 81.5%, P = 0.04) and greater decrease in systolic blood pressure (- 9 vs - 6 mmHg, P = 0.03).

CONCLUSIONS

The 4-minute and 5-minute dipyridamole infusion protocols produce comparable myocardial flow response, hemodynamic changes, and symptoms, in subjects with low likelihood of significant obstructive CAD.

Practical instructions for using drugs in CT and MR cardiac imaging

The progressive increase in numbers of noninvasive cardiac imaging examinations broadens the spectrum of knowledge radiologists are expected to acquire in the management of drugs during CT coronary angiography (CTCA) and cardiac MR (CMR) to improve image quality for optimal visualization and assessment of the coronary arteries and adequate MR functional analysis. Aim of this review is to provide an overview on different class of drugs (nitrate, beta-blockers, ivabradine, anxiolytic, adenosine, dobutamine, atropine, dipyridamole and regadenoson) that can be used in CTCA and CMR, illustrating their main indications, contraindications, efficacy, mechanism of action, metabolism, safety, side effects or complications, and providing advices in their use.

Prognostic value of heart rate reserve is additive to coronary flow velocity reserve during dipyridamole stress echocardiography

BACKGROUND

During dipyridamole stress echocardiography (SE), a blunted heart rate reserve (HRR) is a prognostically unfavourable sign of cardiac autonomic dysfunction.

AIM

To assess the prognostic meaning of HRR and coronary flow velocity reserve (CFVR).

METHODS

The study group comprised 2149 patients (1236 men; mean age 66±12 years) with suspected (n=1280) or known (n=869) coronary artery disease and without inducible regional wall motion abnormalities (RWMA) during dipyridamole SE (0.84mg/kg in 6min). We assessed CFVR of the left anterior descending artery with pulsed-wave Doppler as the ratio between hyperaemic peak and basal peak diastolic flow velocities (abnormal value≤2.0). HRR was calculated as the peak/resting ratio of heart rate from a 12-lead electrocardiogram (abnormal value≤1.22). All patients were followed up.

RESULTS

CFVR and HRR were abnormal in 520 (24%) and 670 (31%) patients, respectively. There was a positive linear correlation between CFVR and HRR (r=0.30; P<0.0001). During a median follow-up of 22 months (1st quartile 12 months, 3rd quartile 35 months), 75 (6%) patients died. The annual mortality was 1.6% in the overall population, 0.5% in the 1224 (57%) patients with normal CFVR and HRR, 1.7% in the 405 (19%) patients with abnormal HRR only, 3.6% in the 255 (12%) patients with abnormal CFVR only, and 6.2% in the 265 (12%) patients with abnormal CFVR and HRR.

CONCLUSIONS

HRR is weakly related to CFVR, and a blunted HRR usefully complements RWMA and CFVR for prediction of outcome with dipyridamole SE. The patient without inducible RWMA is still at intermediate risk, but the risk is low with concomitant preserved CFVR, and very low with concomitant normal HRR.

Dipyridamole-loaded 3D-printed bioceramic scaffolds stimulate pediatric bone regeneration in vivo without disruption of craniofacial growth through facial maturity

This study investigates a comprehensive model of bone regeneration capacity of dypiridamole-loaded 3D-printed bioceramic (DIPY-3DPBC) scaffolds composed of 100% beta-tricalcium phosphate (β -TCP) in an immature rabbit model through the time of facial maturity. The efficacy of this construct was compared to autologous bone graft, the clinical standard of care in pediatric craniofacial reconstruction, with attention paid to volume of regenerated bone by 3D reconstruction, histologic and mechanical properties of regenerated bone, and long-term safety regarding potential craniofacial growth restriction. Additionally, long-term degradation of scaffold constructs was evaluated. At 24 weeks in vivo, DIPY-3DPBC scaffolds demonstrated volumetrically significant osteogenic regeneration of calvarial and alveolar defects comparable to autogenous bone graft with favorable biodegradation of the bioactive ceramic component in vivo. Characterization of regenerated bone reveals osteogenesis of organized, vascularized bone with histologic and mechanical characteristics comparable to native bone. Radiographic and histologic analyses were consistent with patent craniofacial sutures. Lastly, through application of 3D morphometric facial surface analysis, our results support that DIPY-3DPBC scaffolds do not cause premature closure of sutures and preserve normal craniofacial growth. Based on this novel evaluation model, this DIPY-3DPBC scaffold strategy is a promising candidate as a safe, efficacious pediatric bone tissue engineering strategy.

Prolonged dipyridamole administration reduces myocardial perfusion defects in experimental chronic Chagas cardiomyopathy

BACKGROUND

Myocardial perfusion defects (MPD) due to coronary microvascular dysfunction is frequent in chronic Chagas cardiomyopathy (CCC) and may be involved with development of myocardial damage. We investigated whether MPD precedes left ventricular systolic dysfunction and tested the hypothesis that prolonged use of dipyridamole (DIPY) could reduce MPD in an experimental model of CCC in hamsters.

METHODS AND RESULTS

We investigated female hamsters 6-months after T. cruzi infection (baseline condition) and control animals, divided into T. cruzi-infected animals treated with DIPY (CH + DIPY) or placebo (CH + PLB); and uninfected animals treated with DIPY (CO + DIPY) or placebo (CO + PLB). The animals were submitted to echocardiogram and rest SPECT-Sestamibi-Tc99m myocardial perfusion scintigraphy. Next, the animals were treated with DIPY (4 mg/kg bid, intraperitoneal) or saline for 30 days, and reevaluated with the same imaging methods. At baseline, the CH + PLB and CH + DIPY groups showed larger areas of perfusion defect (13.2 ± 13.2% and 17.3 ± 13.2%, respectively) compared with CO + PLB and CO + DIPY (3.8 ± 2.2% e 3.5 ± 2.7%, respectively), P < .05. After treatment, we observed: reduction of perfusion defects only in the CH + DIPY group (17.3 ± 13.2% to 6.8 ± 7.6%, P = .001) and reduction of LVEF in CH + DIPY and CH + PLB groups (from 65.3 ± 9.0% to 53.6 ± 6.9% and from 69.3 ± 5.0% to 54.4 ± 8.6%, respectively, P < .001). Quantitative histology revealed greater extents of inflammation and interstitial fibrosis in both Chagas groups, compared with control group (P < .001), but no difference between Chagas groups (P > .05).

CONCLUSIONS

The prolonged use of DIPY in this experimental model of CCC has reduced the rest myocardial perfusion defects, supporting the notion that those areas correspond to viable hypoperfused myocardium.

Usefulness of Blunted Heart Rate Reserve as an Imaging-Independent Prognostic Predictor During Dipyridamole Stress Echocardiography

A blunted heart rate (HR) response during dipyridamole myocardial perfusion imaging has been associated with a poor outcome. To assess the value of HR response in patients who underwent high-dose dipyridamole stress echocardiography (SE), we retrospectively selected a sample of 3,059 patients (none with pacemakers or atrial fibrillation; mean age 66 ± 11 years). All underwent high-dose (0.84 mg/kg) dipyridamole SE for evaluation of known or suspected coronary artery disease and/or heart failure in 2 laboratories of Pisa-IFC and Lucca. HR (with 12-lead ECG) was obtained each minute and recorded at rest and peak stress. HR reserve (HRR) was calculated as the peak/rest HR ratio. All patients were followed up. Patients were randomly divided into the modeling and validation group of equal size. During a median follow-up time of 1,004 days, 321 hard events occurred: 231 deaths and 90 nonfatal myocardial infarctions. HRR ≤ 1.22 identified by receiver operating characteristic analysis in the modeling group was an independent predictor of infarction-free survival in the modeling (hazard ratio 1.83, 95% confidence interval [CI] 1.30 to 2.60, p = 0.001), in the validation (hazard ratio 1.47, 95% CI 1.08 to 2.01, p = 0.02), and in the overall group (hazard ratio 1.60, 95% CI 1.27 to 2.02, p <0.0001), either off- or on-β blockers. Five-year event rate increased from 8% to 24 % from the highest (≥1.41) to the lowest (≤1.14) HRR quartile. In conclusion, blunted HRR is a useful nonimaging predictor of adverse events during high-dose dipyridamole SE, independent of inducible ischemia, and beta-blocker therapy.

Randomized Comparison of Clinical Effectiveness of Pharmacologic SPECT and PET MPI in Symptomatic CAD Patients

OBJECTIVES

This study compared the clinical effectiveness of pharmacologic stress myocardial perfusion imaging (MPI) plus positron emission tomography (PET) with single-photon emission computed tomography (SPECT) in patients with known coronary artery disease (CAD) presenting with symptoms suggestive of ischemia.

BACKGROUND

Although PET MPI has been shown to have higher diagnostic accuracy in detecting hemodynamically significant CAD than SPECT MPI, whether this impacts downstream management has not been formally evaluated in randomized trials.

METHODS

This study consisted of a single-center trial in which patients with known CAD and suspected ischemia were randomized to undergo PET or attenuation-corrected SPECT MPI between June 2009 and September 2013. Post-test management was at the discretion of the referring physician, and patients were followed for 12 months. The primary endpoint was diagnostic failure, defined as unnecessary angiography (absence of ≥50% stenosis in ≥1 vessel) or additional noninvasive testing within 60 days of the MPI. Secondary endpoints were post-test escalation of antianginal therapy, referral for angiography, coronary revascularization, and health status at 3, 6, and 12 months.

RESULTS

A total of 322 patients with an evaluable MPI were randomized (n = 161 in each group). At baseline, 88.8% of patients were receiving aspirin therapy, 76.7% were taking beta-blockers, and 77.3% were taking statin therapy. Diagnostic failure within 60 days occurred in only 7 patients (2.2%) (3 [1.9%] in the PET group and 4 [2.5%] in the SPECT group; p = 0.70). There were no significant differences between the 2 groups in subsequent rates of coronary angiography, coronary revascularization, or health status at 3, 6, and 12 months of follow-up (all p values ≥0.20); however, when subjects were stratified by findings on MPI in a post hoc analysis, those with high-risk MPI on PET testing had higher rates of angiography and revascularization on follow-up than those who had SPECT MPI, whereas those undergoing low-risk PET studies had lower rates of both procedures than those undergoing SPECT (interaction between randomized modality ∗high-risk MPI for 12-month catheterization [p = 0.001] and 12-month revascularization [p = 0.09]).

CONCLUSIONS

In this contemporary cohort of symptomatic CAD patients who were optimally medically managed, there were no discernible differences in rates of diagnostic failure at 60 days, subsequent coronary angiography, revascularization, or patient health status at 1 year between patients evaluated by pharmacologic PET compared with those evaluated by SPECT MPI. Downstream invasive testing rates with PET MPI were more consistent with high-risk features than those with SPECT MPI. (Effectiveness Study of Single Photon Emission Computed Tomography [SPECT] Versus Positron Emission Tomography [PET] Myocardial Perfusion Imaging; NCT00976053).

Non-contrast assessment of microvascular integrity using arterial spin labeled cardiovascular magnetic resonance in a porcine model of acute myocardial infarction

BACKGROUND

Following acute myocardial infarction (AMI), microvascular integrity and function may be compromised as a result of microvascular obstruction (MVO) and vasodilator dysfunction. It has been observed that both infarcted and remote myocardial territories may exhibit impaired myocardial blood flow (MBF) patterns associated with an abnormal vasodilator response. Arterial spin labeled (ASL) CMR is a novel non-contrast technique that can quantitatively measure MBF. This study investigates the feasibility of ASL-CMR to assess MVO and vasodilator response in swine.

METHODS

Thirty-one swine were included in this study. Resting ASL-CMR was performed on 24 healthy swine (baseline group). A subset of 13 swine from the baseline group underwent stress ASL-CMR to assess vasodilator response. Fifteen swine were subjected to a 90-min left anterior descending (LAD) coronary artery occlusion followed by reperfusion. Resting ASL-CMR was performed post-AMI at 1-2 days (N = 9, of which 6 were from the baseline group), 1-2 weeks (N = 8, of which 4 were from the day 1-2 group), and 4 weeks (N = 4, of which 2 were from the week 1-2 group). Resting first-pass CMR and late gadolinium enhancement (LGE) were performed post-AMI for reference.

RESULTS

At rest, regional MBF and physiological noise measured from ASL-CMR were 1.08 ± 0.62 and 0.15 ± 0.10 ml/g/min, respectively. Regional MBF increased to 1.47 ± 0.62 ml/g/min with dipyridamole vasodilation (P < 0.001). Significant reduction in MBF was found in the infarcted region 1-2 days, 1-2 weeks, and 4 weeks post-AMI compared to baseline (P < 0.03). This was consistent with perfusion deficit seen on first-pass CMR and with MVO seen on LGE. There were no significant differences between measured MBF in the remote regions pre and post-AMI (P > 0.60).

CONCLUSIONS

ASL-CMR can assess vasodilator response in healthy swine and detect significant reduction in regional MBF at rest following AMI. ASL-CMR is an alternative to gadolinium-based techniques for assessment of MVO and microvascular integrity within infarcted, as well as salvageable and remote myocardium. This has the potential to provide early indications of adverse remodeling processes post-ischemia.

Leucovorin + 5-Fluorouracil plus Dipyridamole in Leucovorin + 5-Fluorouracil-Pretreated Patients with Advanced Colorectal Cancer: A Pilot Study of Three Different Dipyridamole Regimens

Dipyridamole, an inhibitor of nucleoside transport, increases the activity of 5-fluorouracil in a dose-dependent manner. The purpose of the present study was to determine whether dipyridamole with 5-fluorouracil and leucovorin gave an improved therapeutic outcome. Sixty patients entered in the present pilot study had previously received 5-fluorouracil (450 mg/m2) and leucovorin (100 mg/m2), every week, and relapsed during this treatment, which ended at least 6 weeks prior to study entry. Dipyridamole was administered at three different dosing schedules (DS) and methods of administration in three groups of patients. DS I: dipyridamole, 30 mg/m2 in normal saline solution, in 90 min iv infusion, followed by leucovorin, 100 mg/m2 iv push, followed by 5-fluorouracil, 450 mg/m2 in normal saline solution, in 60 min iv infusion, dipyridamole tablets (75 mg) every 12 hrs, continuously during the time of chemotherapy. DS II: dipyridamole, 50 mg/m2 in normal saline solution, in 90 min iv infusion, and the rest was the same as DS I. DS III: without oral dipyridamole, patients received dipyridamole (50 mg/m2) iv in the same manner as in DS I and II. Treatment was continued until tumor progression or unacceptable toxicity. All patients (n = 60) entered in the present study were assessable for response and toxicity. No complete response was observed. No patient at DS I responded, whereas 2 patients at DS II and 3 at DS III had a partial response (P <0.1). Stable disease was found with DS I (n = 1), DS II (n = 8) and DS III (n = 9) (P <0.01). More patients progressed at DS I (n = 19) than at DS II (n = 10) and DS III (n = 8) (P <0.0007). The median duration of response was 11 weeks (range, 8-16). Time to progression was 17 weeks for DS I, 15 weeks (range, 10-19) for DS II, and 14 weeks (range, 11-21) for DS III (P = 0.43). Median survival did not differ significantly between DS I (29 weeks; range, 14-48), DS II (31.5 weeks; range, 17-63) and DS III (36 weeks; range, 16-58) (P = 0.2). Neutropenia was most severe with DS I (grade 2, P <0.01) and DS II (grade 1, P <0.05) and nausea/vomiting with DS I (grade 0, P < 0.0005, grade 1, P <0.0002, grade 2, P <0.02) and DS III (grade 3, P <0.0009). Diarrhea was most severe in DS II (grade 3, P <0.005). Mucositis was increased in DS II (grade 0, P <0.008), anorexia in DS II (grade 0, P <0.032) and fatigue in DS I (grade 0, P <0.003). More patients in DS I than with the other two DS experienced headache (P <0.044). According to the response achieved at DS III (15% partial response and 45% stable disease) and the toxicity which was well tolerated mainly in this DS (except for nausea and vomiting grade 3, P <0.009), it can be stated that DS III is the appropriate dose and the simplest schedule of administration (administration of dipyridamole during therapy only). In conclusion, it appears that dipyridamole might still have a role in enhancing the clinical activity of drugs involved in the inhibition of the thymidylate synthetase biochemical pathway and its activity in combination with these agents (5-fluorouracil + leucovorin) as frontline treatment should therefore be explored in future phase II studies.

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.

Aspirin plus dipyridamole has the highest surface under the cumulative ranking curves (SUCRA) values in terms of mortality, intracranial hemorrhage, and adverse event rate among 7 drug therapies in the treatment of cerebral infarction

BACKGROUND

The standardization for the clinical use of drug therapy for cerebral infarction (CI) has not yet determined in some aspects. In this paper, we discussed the efficacies of different drug therapies (aspirin, aspirin plus dipyridamole, aspirin plus clopidogrel, aspirin plus warfarin, cilostazol, warfarin, and ticlopidine) for CI.

METHODS

We searched databases of PubMed and Cochrane Library from the inception to April, 2017, randomized controlled trials (RCTs) met the inclusion and exclusion criteria were enrolled in this study. The network meta-analysis integrated evidences of direct and indirect comparisons to assess odd ratios (OR) and surface under the cumulative ranking curves (SUCRA) value.

RESULTS

Thirteen eligible RCTs including 7 drug therapies were included into this network meta-analysis. The network meta-analysis results showed that CI patients who received aspirin plus dipyridamole presented lower mortality when compared with those received aspirin plus clopidogrel (OR = 0.46, 95% CI = 0.18-0.99), indicating aspirin plus dipyridamole therapy had better efficacy for CI. As for intracranial hemorrhage (ICH), stroke recurrence, and adverse event (AE) rate, there were no significant differences of efficacy among 7 drug therapies. Besides, SUCRA values demonstrated that in the 7 drug therapies, aspirin plus dipyridamole therapy was more effective than others (mortality: 80.67%; ICH: 76.6%; AE rate: 90.2%).

CONCLUSIONS

Our findings revealed that aspirin plus dipyridamole therapy might be the optimum one for patients with CI, which could help to improve the survival of CI patients.

Mitochondrial Uptake of Sestamibi Distinguishes Between Normal, Inflammatory Breast Changes, Pre-Cancers, and Infiltrating Breast Cancer

The evaluation of breast tissue using nuclear imaging is dependent upon the delivery and uptake of the isotope by breast tissue. This is dependent upon blood flow to the breast and functioning mitochondria. This 2-part study investigated (1) differences in uptake of sestamibi when blood flow is enhanced (breast enhanced scintigraphy test [BEST]), and (2) differences in isotope uptake in normal (Nl) breast tissue, inflammatory changes in breast tissue (ICB), and breast cancer (CA). In the first part of the study, 10 women were compared using both Miraluma and BEST imaging; in the second part, 195 people were studied using BEST imaging only. The results were compared with histopathologic specimens. Little difference was noted between Miraluma and BEST imaging in the first part. Women with ICB showed a statistically significant ( P< .05) increase in isotope uptake using BEST imaging. This difference was even more significant ( P< .005) in women with CA. During the second part of the study, BEST imaging demonstrated an exponential increase in tracer uptake. When maximal count activity was compared, there was a statistically significant ( P<.001) difference between Nl and ICB, between ICB and atypia (A), and between A and CA. BEST imaging demonstrated significant increases in isotope delivery when compared with Miraluma imaging. These differences allowed differentiation of breast tissue, including the detection of early changes in breast tissue.

The CADISS Trial Investigators. Antiplatelet Therapy vs. Anticoagulation in Cervical Artery Dissection: Rationale and Design of the Cervical Artery Dissection in Stroke Study (CADISS)

Rationale

Cervical artery dissection is an important cause of stroke in the young. It can present with local symptoms or stroke/transient ischaemic attacks. Following presentation there is a risk of stroke, particularly in the first month following presentation. The mechanism of stroke is believed to be thromboembolic in the majority of cases. Many clinicians anticoagulate patients with cervical dissection for 3–6 months. This is not evidence based and is supported by a paucity of data and no data from randomised control trials.

Aims

CADISS is a prospective multicentre randomised-con-trolled trial in acute (within 7 days of onset) carotid and vertebral artery dissection. Intracerebral artery dissection is excluded.

Design

Patients are randomised to antiplatelet therapy (aspirin, dipyridamole or clopidogrel alone or in dual combination) or anticoagulation therapy [heparin followed by warfarin aiming for an International Normalised Ratio (INR) in the range 2–3] for at least 3 months. Treatment is open-label.

Study outcome

The primary end-point is ipsilateral stroke or death within 3 months from randomisation. Secondary end-points include any TIA or stroke, major bleeding and presence of residual stenosis at 3 months (> 50%). All neuroimaging and serious adverse events will be adjudicated blinded to treatment. An initial feasibility phase of 250 subjects will allow us to determine whether there are sufficient clinical end-points to provide the power to determine a treatment effect and adequate numbers of patients can be recruited. The feasibility phase will be continued into a fully powered definitive treatment trial. Initial power calculations based on limited natural history data suggest a sample size of approximately 3000. Sample size calculations will be refined once the frequency of outcome events during the feasibility phase is known.

Antiplatelet regimens in the long-term secondary prevention of transient ischaemic attack and ischaemic stroke: an updated network meta-analysis

OBJECTIVE

To examine the comparative efficacy and safety of different antiplatelet regimens in patients with prior non-cardioembolic ischaemic stroke or transient ischaemic attack.

DESIGN

Systematic review and network meta-analysis.

DATA SOURCES

As on 31 March 2015, all randomised controlled trials that investigated the effects of antiplatelet agents in the long-term (≥ 3 months) secondary prevention of non-cardioembolic transient ischaemic attack or ischaemic stroke were searched and identified.

OUTCOME MEASURES

The primary outcome measure of efficacy was serious vascular events (non-fatal stroke, non-fatal myocardial infarction and vascular death). The outcome measure of safety was any bleeding.

RESULTS

A total of 36 randomised controlled trials (82,144 patients) were included. Network meta-analysis showed that cilostazol was significantly more effective than clopidogrel (OR 0.77, 95% credible interval 0.60-0.98) and low-dose (75-162 mg daily) aspirin (0.69, 0.55-0.86) in the prevention of serious vascular events. Aspirin (50 mg daily) plus dipyridamole (400 mg daily) and clopidogrel reduced the risk of serious vascular events compared with low-dose aspirin; however, the difference was not statistically significant. Furthermore, low-dose aspirin was as effective as higher daily doses. Cilostazol was associated with a significantly lower bleeding risk than most of the other regimens. Moreover, aspirin plus clopidogrel was associated with significantly more haemorrhagic events than other regimens. Direct comparisons showed similar results as the network meta-analysis.

CONCLUSIONS

Cilostazol was significantly more effective than aspirin and clopidogrel alone in the long-term prevention of serious vascular events in patients with prior non-cardioembolic ischaemic stroke or transient ischaemic attack. Cilostazol was associated with a significantly lower bleeding risk than low-dose aspirin (75-162 mg daily) and aspirin (50 mg daily) plus dipyridamole (400 mg daily). Low-dose aspirin was as effective as higher daily doses. However, further large, randomised, controlled, head-to-head trials are needed, especially in non-Asian ethnic groups.

Development of pH-Independent Drug Release Formulation Using Lipocalin-Type Prostaglandin D Synthase

The purpose of this study was to develop a pH-independent drug release formulation using lipocalin-type prostaglandin D synthase, a member of the lipocalin superfamily, with the function of forming complexes together with various small lipophilic molecules. Dipyridamole, a poorly water-soluble drug, showing a pH-dependent solubility profile, was used as the model drug. The solubilization of dipyridamole was achieved by a simple complex formulation method with lipocalin-type prostaglandin D synthase. The complex formulation was produced successfully by spray drying, and the obtained powder formulation showed complete dissolution in fasted-state simulated gastric fluid (pH, 1.6) and phosphate-buffered solution (pH, 6.8). In addition, the potential stability of the complex formulation was assessed, and the dissolution profile of the produced powder at pH 6.8 was maintained after 4-week storage under several storage conditions. Furthermore, a pharmacokinetic study using hypochlorhydria model rats was performed to verify the improvement of the intestinal absorption behavior, and eventually the complex formulation overcame the problematic absorption profile of dipyridamole in the elevated gastric pH conditions. These results, taken together, demonstrate that the use of this well-designed drug-delivery carrier is feasible for the development of pH-independent drug release formulations.

Association between coronary flow reserve and exercise capacity

INTRODUCTION

Reduced exercise capacity is of clinical importance. Sometimes no corresponding cardiovascular disease can be found to explain this condition. We hypothesized that coronary microvascular dysfunction may have an effect on exercise capacity in patients without apparent cardiovascular disease.

METHODS

Fifty patients (33 female, mean age 46.8 ± 12.4 years) without coronary artery or other cardiac disease were enrolled. Coronary microvascular function was evaluated by measurement of coronary flow reserve (CFR) during transthoracic pulsed-wave Doppler echocardiography with pharmacological stress. CFR was calculated as the ratio of hyperemic to baseline peak diastolic velocities after dipyridamole infusion. Exercise capacity was determined by treadmill exercise testing. Exercise time, metabolic equivalent (MET), and Duke treadmill score (DTS) were recorded and compared with the CFR data.

RESULTS

CFR was correlated with exercise time (r=0.376, p=0.007), MET (r=0.435, p=0.002) and DTS (r=0.458, p=0.001). Exercise time, MET, and DTS were lower in patients with impaired CFR (<2) than in those with normal CFR (2) (5.3 ± 1.8 min vs. 8.6 ± 2.7 min, p<0.001; 7.3 ± 3.1 vs. 11.4 ± 2.8, p=0.002; -1.75 (-5.9, 5.0) vs. 7.5 (5.2, 9.41), p<0.001; respectively). CFR was lower in patients with MET7 as compared to patients with MET>7 (2.0 ± 0.5 vs. 2.6 ± 0.6, p=0.015).

CONCLUSIONS

CFR is associated with exercise capacity. Thus coronary microvascular dysfunction may be a reason for reduced exercise capacity in patients who have no apparent cardiovascular disease.

Comparison of myocardial perfusion evaluation with single versus dual-energy CT and effect of beam-hardening artifacts

RATIONALE AND OBJECTIVES

We sought to explore the feasibility and diagnostic performance of dual-energy computed tomography (DECT) versus single-energy computed tomography (SECT) for the evaluation of myocardial perfusion in patients with intermediate to high likelihood of coronary artery disease.

MATERIALS AND METHODS

The present prospective study involved patients with known or suspected coronary artery disease referred for myocardial perfusion imaging by single-photon emission computed tomography. Forty patients were included in the study protocol and scanned using DECT imaging (n = 20) or SECT imaging (n = 20). The same pharmacologic stress was used for DECT, SECT, and single-photon emission computed tomography scans.

RESULTS

A total of 1360 left ventricular segments were evaluated by DECT and SECT. The contrast-to-noise ratio was similar between groups (DECT 8.8 ± 2.9 vs. SECT 7.7 ± 4.2; P = .22). The diagnostic performance of DECT was greater than that of SECT in identifying perfusion defects (area under the receiver operating characteristic curve of DECT 0.90 [0.86-0.94] vs SECT 0.80 [0.76-0.84]; P = .0004) and remained unaffected when including only segments affected by beam-hardening artifacts (area under the receiver operating characteristic curve = DECT 0.90 [0.84-0.96) vs. SECT 0.77 [0.69-0.84]; P = .007).

CONCLUSIONS

Our results suggest that myocardial perfusion by DECT imaging is feasible and might have improved diagnostic performance compared to SECT imaging for the assessment of myocardial CT perfusion. Furthermore, the diagnostic performance of DECT remained unaffected by the presence of beam-hardening artifacts.

The PRoFESS trial: future impact on secondary stroke prevention

Patients with transient ischemic attack and ischemic stroke have a high risk of recurrent stroke and death. While aspirin is accepted as standard therapy in these patients, recent trials demonstrate that a combination of aspirin and extended-release dipyridamole or clopidogrel is superior to aspirin monotherapy. Blockade of the renin-angiotensin system with angiotensin-converting enzyme inhibitors or angiotensin-receptor blockers may also reduce recurrent stroke. The ongoing Prevention Regimen for Effectively Avoiding Second Strokes (PRoFESS) trial is designed to evaluate whether extended-release dipyridamole plus aspirin compared with clopidogrel, and whether telmisartan in addition to usual care, in individuals after a stroke, will reduce the risk of further strokes. PRoFESS is a multicenter, randomized, double-blind trial involving 695 sites from 35 countries or regions. The primary outcome for the trial is recurrent stroke, using a time-to-event analysis. Safety is evaluated by assessing the risk of major hemorrhagic and other serious adverse events. 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.

Regadenoson and adenosine are equivalent vasodilators and are superior than dipyridamole- a study of first pass quantitative perfusion cardiovascular magnetic resonance

BACKGROUND

Regadenoson, dipyridamole and adenosine are commonly used vasodilators in myocardial perfusion imaging for the detection of obstructive coronary artery disease. There are few comparative studies of the vasodilator properties of regadenoson, adenosine and dipyridamole in humans. The specific aim of this study was to determine the relative potency of these three vasodilators by quantifying stress and rest myocardial perfusion in humans using cardiovascular magnetic resonance (CMR).

METHODS

Fifteen healthy normal volunteers, with Framingham score less than 1% underwent vasodilator stress testing with regadenoson (400 μg bolus), dipyridamole (0.56 mg/kg) and adenosine (140 μg /kg/min) on separate days. Rest perfusion imaging was performed initially. Twenty minutes later, stress imaging was performed at peak vasodilation, i.e. 70 seconds after regadenoson, 4 minutes after dipyridamole infusion and between 3-4 minutes of the adenosine infusion. Myocardial blood flow (MBF) in ml/min/g and myocardial perfusion reserve (MPR) were quantified using a fully quantitative model constrained deconvolution.

RESULTS

Regadenoson produced higher stress MBF than dipyridamole and adenosine (3.58 ± 0.58 vs. 2.81 ± 0.67 vs. 2.78 ± 0.61 ml/min/g, p = 0.0009 and p = 0.0008 respectively). Regadenoson had a much higher heart rate response than adenosine and dipyridamole respectively (95 ± 11 vs. 76 ± 13 vs. 86 ± 12 beats/ minute) When stress MBF was adjusted for heart rate, there were no differences between regadenoson and adenosine (37.8 ± 6 vs. 36.6 ± 4 μl/sec/g, p = NS), but differences between regadenoson and dipyridamole persisted (37.8 ± 6 vs. 32.6 ± 5 μl/sec/g, p = 0.03). The unadjusted MPR was higher with regadenoson (3.11 ± 0.63) when compared with adenosine (2.7 ± 0.61, p = 0.02) and when compared with dipyridamole (2.61 ± 0.57, p = 0.04). Similar to stress MBF, these differences in MPR between regadenoson and adenosine were abolished when adjusted for heart rate (2.04 ± 0.34 vs. 2.12 ± 0.27, p = NS), but persisted between regadenoson and dipyridamole (2.04 ± 0.34 vs. 1.77 ± 0.33, p = 0.07) and between adenosine and dipyridamole (2.12 ± 0.27 vs. 1.77 ± 0.33, p = 0.01).

CONCLUSIONS

Based on fully quantitative perfusion using CMR, regadenoson and adenosine have similar vasodilator efficacy and are superior to dipyridamole.

Hyperemic stress myocardial perfusion cardiovascular magnetic resonance in mice at 3 Tesla: initial experience and validation against microspheres

BACKGROUND

Dynamic first pass contrast-enhanced myocardial perfusion is the standard CMR method for the estimation of myocardial blood flow (MBF) and MBF reserve in man, but it is challenging in rodents because of the high temporal and spatial resolution requirements. Hyperemic first pass myocardial perfusion CMR during vasodilator stress in mice has not been reported.

METHODS

Five C57BL/6 J mice were scanned on a clinical 3.0 Tesla Achieva system (Philips Healthcare, Netherlands). Vasodilator stress was induced via a tail vein catheter with an injection of dipyridamole. Dynamic contrast-enhanced perfusion imaging (Gadobutrol 0.1 mmol/kg) was based on a saturation recovery spoiled gradient echo method with 10-fold k-space and time domain undersampling (k-t PCA). One week later the mice underwent repeat anaesthesia and LV injections of fluorescent microspheres at rest and at stress. Microspheres were analysed using confocal microscopy and fluorescence-activated cell sorting.

RESULTS

Mean MBF at rest measured by Fermi-function constrained deconvolution was 4.1 ± 0.5 ml/g/min and increased to 9.6 ± 2.5 ml/g/min during dipyridamole stress (P = 0.005). The myocardial perfusion reserve was 2.4 ± 0.54. The mean count ratio of stress to rest microspheres was 2.4 ± 0.51 using confocal microscopy and 2.6 ± 0.46 using fluorescence. There was good agreement between cardiovascular magnetic resonance CMR and microspheres with no significant difference (P = 0.84).

CONCLUSION

First-pass myocardial stress perfusion CMR in a mouse model is feasible at 3 Tesla. Rest and stress MBF values were consistent with existing literature and perfusion reserve correlated closely to microsphere analysis. Data were acquired on a 3 Tesla scanner using an approach similar to clinical acquisition protocols, potentially facilitating translation of imaging findings between rodent and human studies.

Pharmacokinetics and pharmacodynamics of the antiplatelet combination aspirin (acetylsalicylic acid) plus extended-release dipyridamole are not altered by coadministration with the potent CYP2C19 inhibitor omeprazole

BACKGROUND

The fixed-dose combination of aspirin (acetylsalicylic acid) 25 mg plus extended-release dipyridamole 200 mg (ASA+ER-DP) is used for long-term secondary stroke prevention in patients who have experienced non-cardioembolic stroke or transient ischemic attack. Although the theoretical risk is low that the antiplatelet activity of ASA+ER-DP will be affected by concomitant use of a proton pump inhibitor (PPI), no formal drug-drug interaction studies have been conducted.

OBJECTIVE

This study aimed to determine whether the PPI omeprazole influences the pharmacokinetic (PK) and pharmacodynamic (PD) behavior of ASA+ER-DP.

STUDY DESIGN AND SETTING

This was a randomized, open-label, multiple-dose, crossover, drug-drug interaction study carried out in a clinical trial unit.

PARTICIPANTS

Sixty healthy male and female volunteers aged 18-50 years were included in the study.

INTERVENTION

Participants were randomized to one of two treatment sequences (ABCD or CDAB), each comprising four 7-day treatments with a washout of ≥14 days between the second and third treatments. Treatment A=ASA+ER-DP 25 mg/200 mg (Aggrenox®) twice daily (BID) alone; B=ASA+ER-DP 25 mg/200 mg BID+omeprazole (Prilosec®) 80 mg once daily (QD) following ASA+ER-DP alone for 7 days; C=omeprazole 80 mg QD alone; D=omeprazole 80 mg QD+ASA+ER-DP 25 mg/200 mg BID following omeprazole alone for 7 days.

MAIN OUTCOME MEASURES

The main outcome measures were systemic PK exposure to ER-DP and ASA inhibition of arachidonic acid-induced platelet aggregation.

RESULTS

Systemic exposure to ER-DP was similar with and without omeprazole, based on steady-state area under the concentration-time curve (AUC) from 0 to 12 h (AUC0-12,ss, ng·h/mL) and maximum plasma concentration (Cmax,ss, ng/mL). For the treatment comparison D versus A, the percent mean ratios were 96.38 (90% confidence interval [CI] 90.96-102.13) for AUC0-12,ss and 92.03 (86.95-97.40) for Cmax,ss. The ER-DP concentration versus time profiles were nearly superimposable. There was no effect on the PDs of the ASA component: the extent of ASA inhibition of arachidonic acid-induced platelet aggregation was almost identical with and without omeprazole, with a percent mean ratio for treatment D versus A = 99.02 (90 % CI 98.32-99.72) at 4 h after last dose. All treatments were well tolerated.

CONCLUSION

The PK and PD behavior of ASA + ER-DP was not altered by concurrent administration of omeprazole.

[Secondary prevention with clopidogrel after TIA or stroke]

In patients with TIA or stroke of arterial origin various antiplatelet agents, or combinations of these, have been found to be effective to reduce the risk of new vascular complications. International guidelines currently recommend three treatment strategies with antiplatelet agents after TIA or stroke: acetylsalicylic acid in combination with dipyridamole, clopidogrel monotherapy, or alternatively acetylsalicylic acid monotherapy. In the Netherlands, current standard antiplatelet therapy after a TIA or stroke is a combination of acetylsalicylic acid and dipyridamole. Clopidogrel monotherapy is probably equally as effective as the combination of acetylsalicylic acid and dipyridamole. Clopidogrel monotherapy is easier to use, has fewer side effects and has recently become cheaper than the combination of acetylsalicylic acid and dipyridamole. For secondary prevention in the Netherlands we advise following the international guidelines on thromboprophylaxis after TIA or stroke. Clopidogrel could be considered as an alternative treatment to the combination of acetylsalicylic acid and dipyridamole.

Myocardial perfusion imaging laboratory efficiency with the use of regadenoson compared to adenosine and dipyridamole

OBJECTIVE

Adenosine, dipyridamole, and regadenoson are pharmacologic stress agents used in myocardial perfusion imaging (MPI), to diagnose and monitor coronary artery disease. Clinical studies suggest that regadenoson has pharmacologic properties that simplify the MPI procedure through availability to a wider range of patients and easier administrative requirements. This study assesses the operational advantages and laboratory efficiency associated with the use of regadenoson compared to adenosine and dipyridamole.

METHODS

A web-based survey of 141 nuclear medicine technologists working in US-based cardiovascular imaging laboratories from June-July 2009.

MAIN OUTCOME MEASURES

Descriptive statistics measured the adenosine, dipyridamole, and regadenoson cohorts. Bivariate analyses compared the overall and staff-specific time to conduct an MPI test. The site-specific sub-groups were defined by hospital vs non-hospital setting, hours of operation, number of SPECT cameras, and number of full-time equivalent staff, including nurses, nuclear technologists, physicians, and nurse practitioners/physician assistants.

RESULTS

The total time to conduct an MPI test was shortest with regadenoson 156 (46) min compared to adenosine and dipyridamole 182 (63) and 191 (61) min, respectively. Time from regadenoson administration to the start of the imaging session, including dose calculation and infusion time, was 14.2 min less than adenosine, and 12.0 min less than dipyridamole. The time to manage adverse events was shortest if it occurred with regadenoson compared to adenosine and dipyridamole, with minor exceptions. Due to the nature of survey implementation, possible recall bias may limit the results. Some differences in procedures times may be attributable to differences in laboratories' protocols.

CONCLUSIONS

Overall time savings and time savings stratified by operational ability (number of staff, number of SPECT cameras, hours of operation) translate to a more efficient utilization of laboratory resources when using regadenoson compared to adenosine and dipyridamole. Regadenoson is the most efficient pharmacologic stress agent compared to adenosine and dipyridamole.

What is better antiplatelet agent to prevent recurrent stroke?

Aspirin and Extended-Release Dipyridamole versus Clopidogrel for Recurrent StrokePrevention Regimen for Effectively Avoiding Second Strokes(PRoFESS) Study Group.

Comparative evaluation of treatment with low-dose aspirin plus dipyridamole versus aspirin only in patients with acute ischaemic stroke

BACKGROUND

Previous studies have suggested that pre-stroke treatment with low-dose aspirin (A) could reduce the severity of acute ischaemic stroke, but less is known on the effect of pre-stroke treatment with a combination of aspirin and dipyridamole (A + D) and post-stroke effects of these drugs. The aim of the present study was to evaluate the effect of this drug combination on acute and long-term prognosis of ischaemic stroke.

METHODS

Patients without atrial fibrillation admitted to the stroke unit with acute ischaemic stroke (n = 554) or TIA (n = 108) were studied during acute hospital care and up to 12 months after discharge from hospital.

RESULTS

Prior to acute stroke 62 patients were treated with A + D while 247 patients were treated with A only. No beneficial effects of the combination A + D compared to A only were noted on stroke severity and/or acute in-hospital mortality. However, survival analysis by Cox-proportional hazard model demonstrated lower 12-months all-cause mortality in patients discharged with A + D (n = 275) compared with patients on A only (HR, 0.52; CI, 0.32-0.86; p = 0.011; n = 262) after adjusting for age, baseline NIHSS, previous stroke, previous myocardial infarction and type 2 diabetes. We also noted a tendency towards lower all-cause mortality at 3 months with use of A + D, but this was not statistically significant (p = 0.12).

CONCLUSIONS

Pre-stroke treatment with a combination of low-dose A + D does not reduce the severity of acute stroke, nor does it reduce the acute in-hospital mortality. However, treatment with A + D at discharge from hospital is seemingly associated with lower long-term mortality compared with A only, contrary to the results from previous randomised studies. However, our results must be interpreted with extreme caution considering the non-randomised study design.

Recombinant amphiphilic protein micelles for drug delivery

Amphiphilic block polypeptides can self-assemble into a range of nanostructures in solution, including micelles and vesicles. Our group has recently described the capacity of recombinant amphiphilic diblock copolypeptides to form highly stable micelles. In this report, we demonstrate the utility of protein nanoparticles to serve as a vehicle for controlled drug delivery. Drug-loaded micelles were produced by encapsulating dipyridamole as a model hydrophobic drug with anti-inflammatory activity. Murine studies confirmed the capacity of drug-loaded protein micelles to limit the in vivo recruitment of neutrophils in response to an inflammatory stimulus.

Level of systolic blood pressure within the normal range and risk of recurrent stroke

CONTEXT

Recurrent stroke prevention guidelines suggest that larger reductions in systolic blood pressure (SBP) are positively associated with a greater reduction in the risk of recurrent stroke and define an SBP level of less than 120 mm Hg as normal. However, the association of SBP maintained at such levels with risk of vascular events after a recent ischemic stroke is unclear.

OBJECTIVE

To assess the association of maintaining low-normal vs high-normal SBP levels with risk of recurrent stroke.

DESIGN, SETTING, AND PATIENTS

Post hoc observational analysis of a multicenter trial involving 20,330 patients (age ≥50 years) with recent non-cardioembolic ischemic stroke; patients were recruited from 695 centers in 35 countries from September 2003 through July 2006 and followed up for 2.5 years (follow-up ended on February 8, 2008). Patients were categorized based on their mean SBP level: very low-normal (<120 mm Hg), low-normal (120-<130 mm Hg), high-normal (130-<140 mm Hg), high (140-<150 mm Hg), and very high (≥150 mm Hg).

MAIN OUTCOME MEASURES

The primary outcome was first recurrence of stroke of any type and the secondary outcome was a composite of stroke, myocardial infarction, or death from vascular causes.

RESULTS

The recurrent stroke rates were 8.0% (95% CI, 6.8%-9.2%) for the very low-normal SBP level group, 7.2% (95% CI, 6.4%-8.0%) for the low-normal SBP group, 6.8% (95% CI, 6.1%-7.4%) for the high-normal SBP group, 8.7% (95% CI, 7.9%-9.5%) for the high SBP group, and 14.1% (95% CI, 13.0%-15.2%) for the very high SBP group. Compared with patients in the high-normal SBP group, the risk of the primary outcome was higher for patients in the very low-normal SBP group (adjusted hazard ratio [AHR], 1.29; 95% CI, 1.07-1.56), in the high SBP group (AHR, 1.23; 95% CI, 1.07-1.41), and in the very high SBP group (AHR, 2.08; 95% CI, 1.83-2.37). Compared with patients in the high-normal SBP group, the risk of secondary outcome was higher for patients in the very low-normal SBP group (AHR, 1.31; 95% CI, 1.13-1.52), in the low-normal SBP group (AHR, 1.16; 95% CI, 1.03-1.31), in the high SBP group (AHR, 1.24; 95% CI, 1.11-1.39), and in the very high SBP group (AHR, 1.94; 95% CI, 1.74-2.16).

CONCLUSION

Among patients with recent non-cardioembolic ischemic stroke, SBP levels during follow-up in the very low-normal (<120 mm Hg), high (140-<150 mm Hg), or very high (≥150 mm Hg) range were associated with increased risk of recurrent stroke.

TRIAL REGISTRATION

clinicaltrials.gov Identifier: NCT00153062.

Smart gelation of chitosan solution in the presence of NaHCO3 for injectable drug delivery system

In situ gelling systems are attractive as injectable vehicles for drug delivery. The present work described a novel gelation process of acidic chitosan solution in the presence of sodium bicarbonate (NaHCO(3)). The NaHCO(3) concentration played an important role in this gelling system. When it came within the appropriate range, the chitosan/NaHCO(3) system would stay at sol state in certain condition and showed sol-gel transition from the top to the bottom after heating. The rheological properties of the gelling system, as well as the morphology and erosion behavior of the formed chitosan hydrogels were evaluated as a function of the NaHCO(3) concentration in sols. The hydrogels showed porous morphologies with some diversification depending on the NaHCO(3) concentration, which also affected their erosion behaviors and drug release rates. Moreover, the gelation mechanism of such chitosan/NaHCO(3) system was studied and proposed as the formation of three-dimensional chitosan network with physical junctions thanks to the deprotonation of -NH(3)(+) in chitosan accompanying with the gradual neutralization between HCO(3)(-) and acid. In vivo gelation test was also performed by the dorsal subcutaneous injection of chitosan/NaHCO(3) solution in rat. The formation of in situ gels suggested such system promising applications in injectable drug delivery system.

[The role of coronary reserve in diagnosis of hemodynamically significant stenoses in anterior descending and right coronary arteries: transthoracic ultrasound study]

Analysis of possibilities of transthoracic echocardiography (TTEchoCG) diagnosis of hemodynamically significant stenoses of anterior descending and right coronary arteries (ADCA and RCA) based on Doppler assessment of coronary reserve (CR) was carried out in 73 patients with cardiac pain syndrome (mean age 48+/-7 years, 60 men, 13 women). As a referent method we used coronary angiography. Coronary blood flow at baseline and during administration of a vasodilator (dipyridamole up to 0.84 mg/kg) was assessed by broadband ultrasound transducer in the mode of noncontrast tissue second harmonic imaging in distal segments of ADCA and posterior interventricular artery (PIVA). CR was calculated as ratio of peak hyperemic to baseline diastolic coronary blood flow velocity. CR &lt;2.0 was diagnosed as lowered. We found that TTEchoCG was simple noninvasive method of assessment of CR in distal thirds of ADCA and PIVA, which can be fulfilled in 90 and 86%of patients, respectively. We also revealed that hemodynamically significant stenoses of ADCA and PIVA caused CR lowering distally to zone of stenosis and that degree of CR lowering depended on severity of vascular narrowing. We found that CR&lt;2.0 in distal third of ADCA was a predictor of its &gt;50% narrowing with sensitivity 78%, specificity 85%, positive predictive value (PPV) 67%, and negative predictive value (NPV) 90%. In the presence of &gt;70% ADCA stenosis sensitivity and NPV of the parameter reached 100%. We revealed that CR&lt;2.0 in PIVA served as a marker of &gt;50% RCA stenosis with sensitivity 88%, specificity 86%, PPV 68%, and NPV 95%. In the presence of &gt;70% RCA stenosis sensitivity and NPV of the parameter rose up to 92 and 97%, respectively.

Blunted heart rate response as a predictor of cardiac death in patients undergoing vasodilator stress technetium-99m sestamibi gated SPECT myocardial perfusion imaging

INTRODUCTION

The prognostic value of a blunted heart rate response (BHR) during ECG-gated vasodilator stress SPECT MPI in relation to ventricular function on long-term cardiovascular events is not well established. We performed this study to evaluate the incremental prognostic value of BHR during pharmacological stress SPECT MPI.

METHODS

Consecutive patients who underwent dipyridamole stress Tc-99m sestamibi ECG-gated SPECT MPI (without exercise) were identified. The ratio of peak stress heart rate to baseline was noted. If the ratio was <1.20, it was considered blunted (BHR). The images were interpreted using the standard ASNC 17 segment model. Patients were followed up for a mean time period of 2.3 +/- 1.5 years.

RESULTS

Sixty-four percent (2,890/4,484) of patients demonstrated BHR during dipyridamole stress testing. Cardiac death, the primary end point, occurred in 6.8% of patients. Patients with BHR had a significantly lower cardiac death-free survival as compared to NO BHR group in total population (83% vs 94%; P < .001) as well as in subgroup with normal ejection fraction (89% vs 96%; P < .001). BHR was an independent predictor of cardiac death after adjusting for multiple clinical, perfusion, and function-related gated SPECT variables.

CONCLUSION

Blunted heart rate response during vasodilator stress SPECT MPI is an important prognostic marker for cardiac death.

Impact of persistence with antiplatelet therapy on recurrent ischemic stroke and predictors of nonpersistence among ischemic stroke survivors

OBJECTIVE

Medication adherence is an important component of effective secondary stroke prevention. The objectives of this study were to examine the impact of persistence with two prescription antiplatelet therapies on the outcome of recurrent hospitalized stroke, and to identify the predictors of nonpersistence with these antiplatelet therapies.

RESEARCH DESIGN AND METHODS

Administrative claims from a large, geographically diverse US health plan were used to evaluate acetylsalicylic acid / extended-release dipyridamole (ASA/ERDP) treated and clopidogrel treated patients from November 1, 2002 - December 31, 2005 who had an ischemic stroke requiring hospitalization. Nonpersistence was defined as failure to refill index medication within 30 days from the run-out date of the prior prescription. A Cox proportional hazards model was used to identify key factors associated with time to nonpersistence.

MAIN OUTCOME MEASURES

Patient demographic variables, clinical characteristics, comorbidities hypothesized to affect the risk of current stroke, stroke outcomes, treatment patterns, and compliance were assessed.

RESULTS

A total of 1413 patients hospitalized for ischemic stroke were identified. Mean age was 63.4 years and 44.2% were female. The proportion of patients persistent per person-year was 45.1%. Persistence with medication was significantly associated with a longer time to recurrent hospitalized stroke (HR 0.275; 95% CI 0.134-0.564; p < 0.0004). A medication copayment of >$40 (relative to a copayment of < or =$20) was the only significant factor predicting time to nonpersistence (HR 1.320; 95% CI 1.091-1.596; p < 0.0042).

CONCLUSIONS

Persistence with antiplatelet medication within a cohort of hospitalized ischemic stroke patients was associated with a 72.5% lower likelihood of recurrent hospitalized stroke. Higher medication copayment was found to negatively impact patient persistence with antiplatelet therapy. The findings of this study must be considered within the limitations of database analysis, as claims data are collected for the purpose of payment and not research.

Effects of aspirin, clopidogrel and dipyridamole administered singly and in combination on platelet and leucocyte function in normal volunteers and patients with prior ischaemic stroke

The aim of this study was to assess whether triple antiplatelet therapy is superior to dual and mono therapy in attenuating platelet and leucocyte function. Aspirin (A), clopidogrel (C), and dipyridamole (D) were administered singly and in various combinations (A, C, D, AC, AD, CD, ACD), each for two weeks (without washout) to 11 healthy subjects and to 11 patients with previous ischaemic stroke in two randomised multiway crossover trials. At the end of each two-week period platelet aggregation, platelet-leucocyte conjugate formation and leucocyte activation were measured ex vivo blinded to treatment. Platelets were stimulated with collagen; additional measurements were made with adenosine diphosphate (ADP), platelet activating factor (PAF), adrenaline and the combination of, ADP, PAF and adrenaline. Results show that in the presence of collagen, ACD was superior to all antagonists or combinations, except AC, in reducing aggregation, platelet-leucocyte conjugate formation, and monocyte activation (all p<0.05). ACD was also more potent than other treatments, except AC, in inhibiting the aggregation and platelet-monocyte conjugate formation induced by the combination of ADP, PAF and adrenaline. The effects were similar in both volunteers and stroke patients. No serious adverse events or major bleeding events occurred. Triple antiplatelet therapy did not appear to be more effective than combined aspirin and clopidogrel in moderating platelet and leucocyte function. Any additional clinical benefit provided by dipyridamole may be through other mechanisms of action.

Effect of aspirin, clopidogrel and dipyridamole on soluble markers of vascular function in normal volunteers and patients with prior ischaemic stroke

Although the mechanisms of action by which aspirin, clopidogrel and dipyridamole inhibit platelets are well characterised, their effects on soluble modulators of thrombosis, inflammation, and endothelial function have yet to assessed systematically. In this investigation aspirin (A), clopidogrel (C), and dipyridamole (D) were administered singly and in combination (A, C, D, AC, AD, CD, ACD) in random order for 2 weeks (without washout) to 11 healthy subjects and 11 patients with previous ischaemic stroke. At the end of each treatment period plasma cyclic guanosine monophosphate (cGMP), monocyte chemoattractant pertide-1 (MCP-1), nitric oxide metabolites (NO(x)), plasminogen activator inhibitor-1 (PAI-1) and von Willebrand factor (vWf); and serum C-reactive protein (CRP) and platelet derived growth factor (PDGF); were measured blinded to treatment. Dipyridamole reduced plasma vWf levels (%) in both volunteers, -10.0 (4.95), and patients, -10.11 (4.34) (p < 0.05). Dipyridamole also lowered CRP (mg/l) in patients, -0.96 (0.47), but not volunteers. Clopidogrel reduced PAI-1 (ng/ml) in volunteers, -5.30 (2.20) (p < 0.05), and patients, -3.61 (2.75) (non-significant trend). Aspirin lowered PDGF (ng/ml) in volunteers, -3.46 (1.55), but not patients. Triple antiplatelet therapy was superior to dual and mono therapy in reducing vWf levels. In conclusion, antiplatelet agents have non-platelet-related effects on soluble modulators of thrombosis, inflammation, and endothelial function. In particular, dipyridamole reduces plasma vWf and clopidogrel lowers plasma PAI-1 levels. These effects may explain, in part, their roles in preventing atherothrombogenesis.

Inhibition of pulmonary metastasis in a human MT3 breast cancer xenograft model by dual liposomes preventing intravasal fibrin clot formation

The process of metastasis formation in cancer is not completely understood and is the main reason cancer therapies fail. Previously, we showed that dual liposomes simultaneously containing the hemostatic inhibitor, dipyridamole and the anticancer drug, perifosine potently inhibited metastasis, causing a 90% reduction in the number of lung metastases in a murine experimental metastasis model. To gain deeper insight into the mechanisms leading to the inhibition of metastasis by these dual liposomes, in the present study, the development of metastases by MT3 breast cancer cells in a mouse xenograft model was analyzed in more detail with regard to tumor cell settlement and metastatic growth. We found that the development of lung metastases by MT3 tumor cells is essentially dependent on the formation of fibrin clots as a precondition for the pulmonary arrest of tumor cells and the subsequent intravascular expansion of micrometastases before their invasion into the surrounding tissue.

Combination antiplatelet therapy for secondary stroke prevention: enhanced efficacy or double trouble?

The evaluation of antithrombotic agents for secondary stroke prevention has focused on stroke reduction. The aim of this analysis was to focus specifically on the increase in bleeding risk. The annualized rates of total and major bleeding events in secondary stroke prevention trials of antithrombotics were assessed and cross compared. A Medline search for major randomized clinical studies with a follow-up duration of > or =1 year identified 13 studies. Pooled data sets were used to compare mean bleeding rates for aspirin (< or =325 mg/day), clopidogrel, anticoagulants (warfarin and other vitamin K antagonists), aspirin plus clopidogrel, and aspirin plus extended-release dipyridamole (ER-DP). Total bleeding occurred at mean rates of 4.8% with aspirin (< or =325 mg/day) alone, 2.9% with clopidogrel alone, 3.6% with aspirin plus ER-DP, 10.1% with aspirin plus clopidogrel, and 16.8% with anticoagulation. Major bleeding occurred at mean rates of 1% with aspirin (< or =325 mg/day) alone, 0.85% with clopidogrel, 0.93% with aspirin plus ER-DP, 1.7% with aspirin plus clopidogrel, and 2.5% with anticoagulation. In conclusion, the combination of aspirin and clopidogrel is associated with significantly greater bleeding than either aspirin (< or =325 mg/day) or clopidogrel alone. Aspirin plus ER-DP has a greater bleeding rate than clopidogrel but a lower rate than aspirin (< or =325 mg/day) alone.

Association of ventricular ectopy with nuclear scintigraphic perfusion defects during dipyridamole stress testing

BACKGROUND AND HYPOTHESIS

No information is available regarding the significance of ventricular ectopic activity induced during dipyridamole nuclear scintigraphic stress testing. This study tested the hypothesis that dipyridamole-induced ventricular ectopy predicts a thallium-201 or technetium-99m sestamibi perfusion defect.

METHODS

A group of 186 consecutive patients with premature ventricular contractions and/or couplets occurring during dipyridamole stress testing (ventricular tachycardia did not occur) was compared with a control group of 194 patients without ventricular ectopy during dipyridamole stress testing.

RESULTS

The results indicated that ventricular ectopy induced during dipyridamole infusion occurred more frequently in patients demonstrating either a fixed or reversible perfusion defect on scintigraphic imaging (p < 0.01). The higher frequency of perfusion defects in this group of patients was attributable to a higher frequency of "fixed" compared with "reversible" defects (p < 0.05). This finding is consistent with the additional observation that ventricular ectopy induced by dipyridamole was associated with the presence of Q waves on the resting ECG (p < 0.05). The positive and negative predictive values of the presence of ventricular ectopy in predicting a fixed myocardial perfusion defect were 59 and 54%, respectively.

CONCLUSIONS

Ventricular ectopy induced during dipyridamole infusion suggests the presence of a fixed myocardial perfusion defect.

[Optimization of a floating osmotic pump system of dipyridamole using central composite design-response surface methodology]

A new type of floating osmotic pump of dipyridamole was designed in this paper. Apparatus three (Chinese Pharmacopeia 2005, appendix XD) was employed for in vitro dissolution test in order to evaluate the release and floating behavior in a same experiment. The system was optimized using central composite design-response surface methodology; where similarity factor (f2) between the dissolution profile of prepared formulation and the target dissolution profile was taken as dependent factor, usage amount of polyoxyethylene (X1, mg), NaCl (X2, mg) and pore former (PEG4000, X3, %) were taken as independent factors. The optimization model was f2 = -29.3 + 2.35X3 - 0.123X1(2) - 0.046X2(2) + 0.145X1X2 (R = 0.996). It was found that the dissolution profile could match the target dissolution profile under the condition of weight gain 8%-9%, X1 (20-34), X2 (30-57), X3 = 50. It is also found that the minimum usage percentage of pore former is 35.1%. The prediction results of the optimization model were good in the experiments.

Characterization, lung targeting profile and therapeutic efficiency of dipyridamole liposomes

The acute respiratory distress syndrome (ARDS) is a severe form of acute lung injury (ALI). Its pathogenesis is closely linked with reactive oxygen species (ROS). Antioxidation has been considered as an efficient treatment. Besides, liposomes are widely investigated as potential drug carriers due to their ability to protect and carry drug molecules to the target organ such as the lung. The present study was undertaken to investigate whether dipyridamole (DIP), delivered as a liposomal preparation, can ameliorate the lipopolysaccharides (LPS)-induced ALI due to the changes of its biodistribution. First, the liposomes entrapping DIP were prepared by film hydration for treating ARDS. Subsequently, the characterizations including entrapment efficiency, size, span and micrograph of DIP liposomes were measured. The concentration change of DIP in tissues and plasma of mice after intravenous administration of DIP injection and DIP liposomes was determined by RP-HPLC and calculated to lung targeting parameters. To prove the therapeutic efficiency, the effects of DIP liposomes on LPS-induced ALI were studied compared with DIP injection. The results showed DIP liposomes have the relative high entrapment efficiency and satisfying particle size. Compared with DIP injection, the liposomes increased the accumulation of DIP in the lung on a vast scale. Furthermore, DIP liposomes alleviated the ALI induced by LPS significantly. All of the results suggested that DIP liposomes have the potential efficacy in treating ALI/ARDS due to their obvious lung targeting.

Statistical Evaluation of Influence of Xanthan Gum and Guar Gum Blends on Dipyridamole Release from Floating Matrix Tablets

The present investigation explored the use of xanthan gum and guar gum for development of floating drug delivery system of dipyridamole using factorial design approach. The content of polymer blends (X(1)) and ratio of xanthan gum to guar gum (X(2)) were selected as independent variables. The diffusion exponent (n), release rate constant (k), percentage drug release at 1 hr (Q(1)) and 6 hr (Q(6)) were selected as dependent variables. Tablets of all batches had desired buoyancy characteristics. Multiple regression analysis with two way ANOVA revealed that both the factors had statistically significant influence on the response studied (p<0.05). Results of Tukey test showed the relative contribution of each level of different factors for the response studied. It was concluded that the ratio of xanthan to gaur gum had equal or dominant role as controlling factor on kinetics of drug release compared to content of polymer blends.

Preparation and Characterization of Solid Dispersions of Dipyridamole with a Carrier “Copolyvidonum Plasdone®S-630”

Solid dispersions (SDs) of dipyridamole (DIP) with a novel carrier copolyvidonum Plasdone S-630 (CoPVP) were developed by solvent evaporation method. The solid state of SDs of DIP with CoPVP (SDs CoPVP) was characterized by fourier transform infrared spectroscopy (FT-IR), differential scanning calorimetry (DSC), X-ray diffraction (XRD) and polarizing microscopy, compared with that of SDs of DIP with polyvinylpyrrolidone Plasdone K-29/32 (SDs PVP). FT-IR analysis demonstrated the presence of intermolecular hydrogen bonding between DIP and CoPVP or PVP in SDs. DSC and XRD studies indicated that DIP presented in amorphous state in both SDs CoPVP and SDs PVP at higher weight ratios. The dissolution property of SDs CoPVP was significantly improved in comparison of pure DIP and physical mixtures with CoPVP (PM CoPVP). Both SDs CoPVP and SDs PVP powder showed the favorable flowability. However, SDs CoPVP showed better compressibility than SDs PVP. The lower hydroscopicity of SDs CoPVP could be advantageous to the stability to SDs. This study proves the potential of CoPVP as a carrier in the formulations of SDs for poorly soluble drugs.

The approach to optimizing stroke care

Stroke is a leading cause of death, disability, and dependence. Treatment of patients with acute stroke requires an integrated, systematic approach with thrombolysis, if indicated, and aggressive supportive care. Subacute treatment of patients with ischemic stroke should focus on the initiation of antithrombotic therapy and prevention of secondary stroke by risk factor modification. Treatment by emergency medicine physicians, who initiate thrombolysis and begin antiplatelet agents, and modification of preexisting risk factors are critical to patient outcome. Because few patients seen in the emergency department are eligible for thrombolysis because of the narrow timeframe for receiving treatment, most patients require antithrombotic therapy with aspirin, clopidogrel, or aspirin in combination with extended-release dipyridamole (ER-DP). Although aspirin, clopidogrel, and aspirin plus ER-DP effectively reduce the risk for recurrent stroke, according to treatment guidelines, clopidogrel alone (particularly in patients allergic to aspirin) and aspirin plus ER-DP are recommended over aspirin alone. Emergency medicine physicians should be aware of the available antiplatelet agents and the importance of antithrombotic therapy for prevention of secondary stroke.

[Current issues of anticoagulation therapy in the course of dental treatment and oral surgery]

More and more patients receiving anticoagulant therapy or other drugs modifying the coagulation mechanism require dental or oral surgical treatment nowadays. The reason is that in Hungary the various forms of thrombosis are on the first place of morbidity and mortality lists. More than 50 per cent of all the mortality is due to thromboembolism. In view of all this it is not surprising that in the past years the indications, application and dosage of anticoagulant and platelet aggregation inhibitor drugs have changed. Decades-old principles have been modified. It is important for dentists and oral surgeons to know the risk of interventions in patients receiving anticoagulant or platelet inhibitory therapy.