Dipyridamole for preventing stroke and other vascular events in patients with vascular disease

Attenuation of HIV-Specific T Cell Responses Among People with HIV on art Following Dipyridamole Treatment

Twelve weeks of dipyridamole increased extracellular adenosine levels and decreased T cell activation in people with HIV. In this analysis, we investigated the effect of dipyridamole on HIV-specific T cell responses. We compared changes in Gag- and Env-specific T cell responses using intracellular cytokine staining, following 12 weeks of dipyridamole treatment vs placebo. We evaluated whether frequencies of polyfunctional HIV-specific T cells were associated with purines in the adenosine pathway and with measures of HIV persistence and chronic inflammation. There was a significant decrease in CD4+ polyfunctional T cell responses to Gag (-62.6% vs -23.0%; p<0.001) and Env (-56.1% vs -6.0%; p<0.001) in the dipyridamole arm. In the dipyridamole group, lower frequencies of polyfunctional Env-specific CD4+ T cells were associated with higher plasma levels of adenosine (r= -0.85; p<0.01) and inosine (r= -0.70; p=0.04). Higher adenosine levels induced by dipyridamole treatment is associated with decreased HIV-specific CD4+ T cell polyfunctional responses in people with HIV on antiretroviral therapy.

Peroxisome proliferator-activated receptor gamma agonists for preventing recurrent stroke and other vascular events in people with stroke or transient ischaemic attack

BACKGROUND

Peroxisome proliferator-activated receptor gamma (PPAR-γ) agonists are insulin-sensitising drugs used for the treatment of insulin resistance. In addition to lowering glucose in diabetes, these drugs may also protect against hyperlipidaemia and arteriosclerosis, which are risk factors for stroke. This is an update of a review first published in January 2014 and subsequently updated in December 2017 and October 2019.

OBJECTIVES

To assess the efficacy and safety of PPAR-γ agonists in the secondary prevention of stroke and related vascular events for people with stroke or transient ischaemic attack (TIA).

SEARCH METHODS

We searched the Cochrane Stroke Group Trials Register (1 January 2022), the Cochrane Central Register of Controlled Trials (CENTRAL; 2021, Issue 12), MEDLINE (1949 to 1 January 2022), Embase (1980 to 1 January 2022), CINAHL (1982 to 1 January 2022), AMED (1985 to 1 January 2022), and 11 Chinese databases (1 January 2022). In an effort to identify further published, unpublished, and ongoing trials, we searched ongoing trials registers, reference lists, and relevant conference proceedings, and contacted authors and pharmaceutical companies. We did not impose any language restrictions.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) evaluating PPAR-γ agonists versus placebo for the secondary prevention of stroke and related vascular events in people with stroke or TIA, with the outcomes of recurrent stroke, vascular events, and adverse events.

DATA COLLECTION AND ANALYSIS

Two review authors independently screened the titles and abstracts of identified records, selected studies for inclusion, extracted eligible data, cross-checked the data for accuracy, and assessed methodological quality and risk of bias. We evaluated the certainty of evidence for each outcome using the GRADE approach.

MAIN RESULTS

We identified five RCTs with 5039 participants; two studies had a low risk of bias for all domains. Four studies evaluated the drug pioglitazone, and one study evaluated rosiglitazone. The participants in different studies were heterogeneous. Recurrent stroke Three studies evaluated the number of participants with recurrent stroke (4979 participants, a single study contributing 3876 of these). Peroxisome proliferator-activated receptor gamma agonists probably reduce the recurrence of stroke compared with placebo (risk ratio (RR) 0.66, 95% confidence interval (CI) 0.44 to 0.99; moderate-certainty evidence). Adverse events Evidence that adverse events occurred more frequently in participants treated with PPAR-γ agonists when compared with placebo was uncertain due to wide confidence intervals and high levels of statistical heterogeneity: risk difference 10%, 95% CI -8% to 28%; low-certainty evidence). Data were available on additional composite outcomes reflecting serious vascular events (all-cause death and other major vascular events; all-cause mortality, non-fatal myocardial infarction or non-fatal stroke) from one study in 984 people. This study provided low-certainty evidence that PPAR-γ agonists led to fewer events (data not meta-analysed). Vascular events Peroxisome proliferator-activated receptor gamma agonists given over a mean duration of 34.5 months in a single trial of 984 participants may reduce serious vascular events expressed as a composite outcome of total events of cardiovascular death, non-fatal myocardial infarction or non-fatal stroke (RR 0.73, 95% CI 0.54 to 0.99; low-certainty evidence). Other outcomes One study in 20 people measured insulin sensitivity, and one study in 40 people measured the ubiquitin-proteasome activity in carotid plaques. Our confidence in the improvements observed with PPAR-γ agonists were limited by small sample sizes and risk of bias. None of the studies reported the number of participants with disability due to vascular events or improvement in quality of life.

AUTHORS' CONCLUSIONS

Peroxisome proliferator-activated receptor gamma agonists probably reduce recurrent stroke and total events of cardiovascular death, non-fatal myocardial infarction or non-fatal stroke, and may improve insulin sensitivity and the stabilisation of carotid plaques. Their effects on adverse events are uncertain. Our conclusions should be interpreted with caution considering the small number and the quality of the included studies. Further well-designed, double-blind RCTs with large samples are required to assess the efficacy and safety of PPAR-γ agonists in the secondary prevention of stroke and related vascular events in people with stroke or TIA.

Antiplatelet Use in Ischemic Stroke

Objective:

A literature review of antiplatelet agents for primary and secondary stroke prevention, including mechanism of action, cost, and reasons for lack of benefit.

Data sources:

Articles were gathered from MEDLINE, Cochrane Reviews, and PubMed databases (1980-2021). Abstracts from scientific meetings were considered. Search terms included ischemic stroke, aspirin, clopidogrel, dipyridamole, ticagrelor, cilostazol, prasugrel, glycoprotein IIb/IIIa inhibitors.

Study selection and data extraction:

English-language original and review articles were evaluated. Guidelines from multiple countries were reviewed. Articles were evaluated independently by 2 authors.

Data synthesis:

An abundance of evidence supports aspirin and clopidogrel use for secondary stroke prevention. In the acute phase (first 21 days postinitial stroke), these medications have higher efficacy for preventing further stroke when combined, but long-term combination therapy is associated with higher hemorrhage rates. Antiplatelet treatment failure is influenced by poor adherence and genetic polymorphisms. Antiplatelet agents such as cilostazol may provide extra benefit over clopidogrel and aspirin, in certain racial groups, but further research in more diverse ethnic populations is needed.

Relevance to patient care and clinical practice:

This review presents the data available on the use of different antiplatelet agents poststroke. Dual therapy, recurrence after initiation of secondary preventative therapy, and areas for future research are discussed.

Conclusions:

Although good evidence exists for the use of certain antiplatelet agents postischemic stroke, there are considerable opportunities for future research to investigate personalized therapies. These include screening patients for platelet polymorphisms that confer antiplatelet resistance and for randomized trials including more racially diverse populations.

Enhancing Extracellular Adenosine Levels Restores Barrier Function in Acute Lung Injury Through Expression of Focal Adhesion Proteins

Background: Acute respiratory distress syndrome (ARDS) is a clinical presentation of acute lung injury (ALI) with often fatal lung complication. Adenosine, a nucleoside generated following cellular stress provides protective effects in acute injury. The levels of extracellular adenosine can be depleted by equilibrative nucleoside transporters (ENTs). ENT inhibition by pharmaceutical agent dipyridamole promotes extracellular adenosine accumulation and is protective in ARDS. However, the therapeutic potential of dipyridamole in acute lung injury has not yet been evaluated. Methods: Adenosine acts on three adenosine receptors, the adenosine A1 (Adora1), A2a (Adora2a), the A2b (Adora2b) or the adenosine A3 (Adora 3) receptor. Accumulation of adenosine is usually required to stimulate the low-affinity Adora2b receptor. In order to investigate the effect of adenosine accumulation and the contribution of epithelial-specific ENT2 or adora2b expression in experimental ALI, dipyridamole, and epithelial specific ENT2 or Adora2b deficient mice were utilized. MLE12 cells were used to probe downstream Adora2b signaling. Adenosine receptors, transporters, and targets were determined in ARDS lungs. Results: ENT2 is mainly expressed in alveolar epithelial cells and is negatively regulated by hypoxia following tissue injury. Enhancing adenosine levels with ENT1/ENT2 inhibitor dipyridamole at a time when bleomycin-induced ALI was present, reduced further injury. Mice pretreated with the ADORA2B agonist BAY 60-6583 were protected from bleomycin-induced ALI by reducing vascular leakage (558.6 ± 50.4 vs. 379.9 ± 70.4, p < 0.05), total bronchoalveolar lavage fluid cell numbers (17.9 ± 1.8 to 13.4 ± 1.4 e4, p < 0.05), and neutrophil infiltration (6.42 ± 0.25 vs. 3.94 ± 0.29, p < 0.05). While mice lacking Adora2b in AECs were no longer protected by dipyridamole. We also identified occludin and focal adhesion kinase as downstream targets of ADORA2B, thus providing a novel mechanism for adenosine-mediated barrier protection. Similarly, we also observed similar enhanced ADORA2B (3.33 ± 0.67 to 16.12 ± 5.89, p < 0.05) and decreased occludin (81.2 ± 0.3 to 13.3 ± 0.4, p < 0.05) levels in human Acute respiratory distress syndrome lungs. Conclusion: We have highlighted a role of dipyridamole and adenosine signaling in preventing or treating ALI and identified Ent2 and Adora2b as key mediators in important for the resolution of ALI.

Umbrella review and meta-analysis of antiplatelet therapy for peripheral artery disease

Background

The literature on antiplatelet therapy for peripheral artery disease has historically been summarized inconsistently, leading to conflict between international guidelines. An umbrella review and meta-analysis was performed to summarize the literature, allow assessment of competing safety risks and clinical benefits, and identify weak areas for future research.

Methods

MEDLINE, Embase, DARE, PROSPERO and Cochrane databases were searched from inception until January 2019. All meta-analyses of antiplatelet therapy in peripheral artery disease were included. Quality was assessed using AMSTAR scores, and GRADE analysis was used to quantify the strength of evidence. Data were pooled using random-effects models.

Results

Twenty-eight meta-analyses were included. Thirty-three clinical outcomes and 41 antiplatelet comparisons in 72 181 patients were analysed. High-quality evidence showed that antiplatelet monotherapy reduced non-fatal strokes (3 (95 per cent c.i. 0 to 6) fewer per 1000 patients), In symptomatic patients, it reduced cardiovascular deaths (8 (0 to 16) fewer per 1000 patients), but increased the risk of major bleeding (7 (3 to 14) more events per 1000). In asymptomatic patients, monotherapy reduced non-fatal strokes (5 (0 to 8) fewer per 1000), but had no other clinical benefit. Dual antiplatelet therapy caused more major bleeding after intervention than monotherapy (37 (8 to 102) more events per 1000), with very low-quality evidence of improved endovascular patency (risk ratio 4·00, 95 per cent c.i. 0·91 to 17·68).

Conclusion

Antiplatelet monotherapy has minimal clinical benefit for asymptomatic peripheral artery disease, and limited benefit for symptomatic disease, with a clear risk of major bleeding. There is a lack of evidence to guide antiplatelet prescribing after peripheral endovascular intervention.

Peroxisome proliferator-activated receptor gamma agonists for preventing recurrent stroke and other vascular events in people with stroke or transient ischaemic attack

BACKGROUND

Peroxisome proliferator-activated receptor gamma (PPAR-γ) agonists are insulin-sensitising drugs used for the treatment of insulin resistance. In addition to lowering glucose in diabetes, these drugs may also protect against hyperlipidaemia and arteriosclerosis, which are risk factors for stroke. This is an update of a review first published in January 2014 and subsequently updated in December 2017.

OBJECTIVES

To assess the efficacy and safety of PPAR-γ agonists in the secondary prevention of stroke and related vascular events for people with stroke or transient ischaemic attack (TIA).

SEARCH METHODS

We searched the Cochrane Stroke Group Trials Register (30 July 2019), the Cochrane Central Register of Controlled Trials (CENTRAL; 2019, Issue 7), MEDLINE (1949 to 30 July 2019), Embase (1980 to 30 July 2019), CINAHL (1982 to 30 July 2019), AMED (1985 to 30 July 2019), and 11 Chinese databases (30 July 2019). In an effort to identify further published, unpublished, and ongoing trials, we searched ongoing trials registers, reference lists, and relevant conference proceedings, and contacted authors and pharmaceutical companies. We did not impose any language restrictions.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) evaluating PPAR-γ agonists versus placebo for the secondary prevention of stroke and related vascular events in people with stroke or TIA, with the outcomes of recurrent stroke, vascular events, and adverse events.

DATA COLLECTION AND ANALYSIS

Two review authors independently screened the titles and abstracts of identified records, selected studies for inclusion, extracted eligible data, cross-checked the data for accuracy, and assessed methodological quality and risk of bias. We evaluated the quality of evidence for each outcome using the GRADE approach.

MAIN RESULTS

We identified five RCTs with 5039 participants; two studies had a low risk of bias for all domains. Four studies evaluated the drug pioglitazone, and one study evaluated rosiglitazone. The participants in different studies were heterogeneous.Recurrent strokeThree studies evaluated the number of participants with recurrent stroke (4979 participants, a single study contributing 3876 of these). Peroxisome proliferator-activated receptor gamma agonists probably reduce the recurrence of stroke compared with placebo (risk ratio (RR) 0.66, 95% confidence interval (CI) 0.44 to 0.99; moderate-quality evidence).Adverse eventsEvidence that adverse events occurred more frequently in participants treated with PPAR-γ agonists when compared with placebo was uncertain due to wide confidence interval and high levels of statistical heterogeneity: risk difference 10%, 95% CI -8% to 28%; low-quality evidence).Data were available on additional composite outcomes reflecting serious vascular events (all-cause death and other major vascular events; all-cause mortality, non-fatal myocardial infarction or non-fatal stroke) from one study in 984 people. This study provided low-quality evidence that PPAR-γ agonists led to fewer events (data not meta-analysed).Vascular eventsPeroxisome proliferator-activated receptor gamma agonists given over a mean duration of 34.5 months in a single trial of 984 participants may reduce serious vascular events expressed as a composite outcome of total events of cardiovascular death, non-fatal myocardial infarction or non-fatal stroke (RR 0.73, 95% CI 0.54 to 0.99; low-quality evidence).Other outcomesOne study in 20 people measured insulin sensitivity, and one study in 40 people measured the ubiquitin-proteasome activity in carotid plaques. Our confidence in the improvements observed with PPAR-γ agonists were limited by small sample sizes and risk of bias. None of the studies reported the number of participants with disability due to vascular events or improvement in quality of life.

AUTHORS' CONCLUSIONS

Peroxisome proliferator-activated receptor gamma agonists probably reduce recurrent stroke and total events of cardiovascular death, non-fatal myocardial infarction or non-fatal stroke, and may improve insulin sensitivity and the stabilisation of carotid plaques. Their effects on adverse events are uncertain. Our conclusions should be interpreted with caution considering the small number and the quality of the included studies. Further well-designed, double-blind RCTs with large samples are required to assess the efficacy and safety of PPAR-γ agonists in the secondary prevention of stroke and related vascular events in people with stroke or TIA.

Platelet Signaling and Disease: Targeted Therapy for Thrombosis and Other Related Diseases

Platelets are essential for clotting in the blood and maintenance of normal hemostasis. Under pathologic conditions such as atherosclerosis, vascular injury often results in hyperactive platelet activation, resulting in occlusive thrombus formation, myocardial infarction, and stroke. Recent work in the field has elucidated a number of platelet functions unique from that of maintaining hemostasis, including regulation of tumor growth and metastasis, inflammation, infection, and immune response. Traditional therapeutic targets for inhibiting platelet activation have primarily been limited to cyclooxygenase-1, integrin αIIbβ3, and the P2Y12 receptor. Recently identified signaling pathways regulating platelet function have made it possible to develop novel approaches for pharmacological intervention in the blood to limit platelet reactivity. In this review, we cover the newly discovered roles for platelets as well as their role in hemostasis and thrombosis. These new roles for platelets lend importance to the development of new therapies targeted to the platelet. Additionally, we highlight the promising receptor and enzymatic targets that may further decrease platelet activation and help to address the myriad of pathologic conditions now known to involve platelets without significant effects on hemostasis.

Peroxisome proliferator-activated receptor gamma agonists for preventing recurrent stroke and other vascular events in people with stroke or transient ischaemic attack

BACKGROUND

Peroxisome proliferator-activated receptor gamma (PPAR-γ) agonists are insulin-sensitising drugs used for the treatment of insulin resistance. In addition to lowering glucose in diabetes, these drugs may also protect against hyperlipidaemia and arteriosclerosis, which are risk factors for stroke. This is an update of a review first published in January 2014 and subsequently updated in October 2015.

OBJECTIVES

To assess the efficacy and safety of PPAR-γ agonists in the secondary prevention of stroke and related vascular events for people with stroke or transient ischaemic attack (TIA).

SEARCH METHODS

We searched the Cochrane Stroke Group Trials Register (16 May 2017), the Cochrane Central Register of Controlled Trials (CENTRAL; 2017, Issue 5), MEDLINE (1949 to 16 May 2017), Embase (1980 to 16 May 2017), CINAHL (1982 to 16 May 2017), AMED (1985 to 16 May 2017), and 11 Chinese databases (16 May 2017). In an effort to identify further published, unpublished, and ongoing trials, we searched ongoing trials registers, reference lists, and relevant conference proceedings, and contacted authors and pharmaceutical companies. We did not impose any language restrictions.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) evaluating PPAR-γ agonists versus placebo for the secondary prevention of stroke and related vascular events in people with stroke or TIA, with the outcomes of recurrent stroke, vascular events, and adverse events.

DATA COLLECTION AND ANALYSIS

Two review authors independently screened the titles and abstracts of identified records, selected studies for inclusion, extracted eligible data, cross-checked the data for accuracy, and assessed methodological quality and risk of bias. We evaluated the quality of evidence for each outcome using the GRADE approach.

MAIN RESULTS

We identified five RCTs with 5039 participants; two studies had a low risk of bias for all domains. Four studies evaluated the drug pioglitazone, and one study evaluated rosiglitazone. The participants in different studies were heterogeneous.Recurrent strokeThree studies evaluated the number of participants with recurrent stroke (4979 participants, a single study contributing 3876 of these). Peroxisome proliferator-activated receptor gamma agonists probably reduce the recurrence of stroke compared with placebo (risk ratio (RR) 0.66, 95% confidence interval (CI) 0.44 to 0.99; moderate-quality evidence).Adverse eventsEvidence that adverse events occurred more frequently in participants treated with PPAR-γ agonists when compared with placebo was uncertain due to wide confidence interval and high levels of statistical heterogeneity: risk difference 10%, 95% CI -8% to 28%; low-quality evidence).Data were available on additional composite outcomes reflecting serious vascular events (all-cause death and other major vascular events; all-cause mortality, non-fatal myocardial infarction or non-fatal stroke) from one study in 984 people. This study provided low-quality evidence that PPAR-γ agonists led to fewer events (data not meta-analysed).Vascular eventsPeroxisome proliferator-activated receptor gamma agonists given over a mean duration of 34.5 months in a single trial of 984 participants may reduce serious vascular events expressed as a composite outcome of total events of cardiovascular death, non-fatal myocardial infarction or non-fatal stroke (RR 0.73, 95% CI 0.54 to 0.99; low-quality evidence).Other outcomesOne study in 20 people measured insulin sensitivity, and one study in 40 people measured the ubiquitin-proteasome activity in carotid plaques. Our confidence in the improvements observed with PPAR-γ agonists were limited by small sample sizes and risk of bias. None of the studies reported the number of participants with disability due to vascular events or improvement in quality of life.

AUTHORS' CONCLUSIONS

Peroxisome proliferator-activated receptor gamma agonists probably reduce recurrent stroke and total events of cardiovascular death, non-fatal myocardial infarction or non-fatal stroke, and may improve insulin sensitivity and the stabilisation of carotid plaques. Their effects on adverse events are uncertain. Our conclusions should be interpreted with caution considering the small number and the quality of the included studies. Further well-designed, double-blind RCTs with large samples are required to assess the efficacy and safety of PPAR-γ agonists in the secondary prevention of stroke and related vascular events in people with stroke or TIA.

Effects of aspirin on risk and severity of early recurrent stroke after transient ischaemic attack and ischaemic stroke: time-course analysis of randomised trials

BACKGROUND

Aspirin is recommended for secondary prevention after transient ischaemic attack (TIA) or ischaemic stroke on the basis of trials showing a 13% reduction in long-term risk of recurrent stroke. However, the risk of major stroke is very high for only the first few days after TIA and minor ischaemic stroke, and observational studies show substantially greater benefits of early medical treatment in the acute phase than do longer-term trials. We hypothesised that the short-term benefits of early aspirin have been underestimated.

METHODS

Pooling the individual patient data from all randomised trials of aspirin versus control in secondary prevention after TIA or ischaemic stroke, we studied the effects of aspirin on the risk and severity of recurrent stroke, stratified by the following time periods: less than 6 weeks, 6-12 weeks, and more than 12 weeks after randomisation. We compared the severity of early recurrent strokes between treatment groups with shift analysis of modified Rankin Scale (mRS) score. To understand possible mechanisms of action, we also studied the time course of the interaction between effects of aspirin and dipyridamole in secondary prevention of stroke. In a further analysis we pooled data from trials of aspirin versus control in which patients were randomised less than 48 h after major acute stroke, stratified by severity of baseline neurological deficit, to establish the very early time course of the effect of aspirin on risk of recurrent ischaemic stroke and how this differs by severity at baseline.

FINDINGS

We pooled data for 15,778 participants from 12 trials of aspirin versus control in secondary prevention. Aspirin reduced the 6 week risk of recurrent ischaemic stroke by about 60% (84 of 8452 participants in the aspirin group had an ischaemic stroke vs 175 of 7326; hazard ratio [HR] 0·42, 95% CI 0·32-0·55, p<0·0001) and disabling or fatal ischaemic stroke by about 70% (36 of 8452 vs 110 of 7326; 0·29, 0·20-0·42, p<0·0001), with greatest benefit noted in patients presenting with TIA or minor stroke (at 0-2 weeks, two of 6691 participants in the aspirin group with TIA or minor stroke had a disabling or fatal ischaemic stroke vs 23 of 5726 in the control group, HR 0·07, 95% CI 0·02-0·31, p=0·0004; at 0-6 weeks, 14 vs 60 participants, 0·19, 0·11-0·34, p<0·0001). The effect of aspirin on early recurrent ischaemic stroke was due partly to a substantial reduction in severity (mRS shift analysis odds ratio [OR] 0·42, 0·26-0·70, p=0·0007). These effects were independent of dose, patient characteristics, or aetiology of TIA or stroke. Some further reduction in risk of ischaemic stroke accrued for aspirin only versus control from 6-12 weeks, but there was no benefit after 12 weeks (stroke risk OR 0·97, 0·84-1·12, p=0·67; severity mRS shift OR 1·00, 0·77-1·29, p=0·97). By contrast, dipyridamole plus aspirin versus aspirin alone had no effect on risk or severity of recurrent ischaemic stroke within 12 weeks (OR 0·90, 95% CI 0·65-1·25, p=0·53; mRS shift OR 0·90, 0·37-1·72, p=0·99), but dipyridamole did reduce risk thereafter (0·76, 0·63-0·92, p=0·005), particularly of disabling or fatal ischaemic stroke (0·64, 0·49-0·84, p=0·0010). We pooled data for 40,531 participants from three trials of aspirin versus control in major acute stroke. The reduction in risk of recurrent ischaemic stroke at 14 days was most evident in patients with less severe baseline deficits, and was substantial by the second day after starting treatment (2-3 day HR 0·37, 95% CI 0·25-0·57, p<0·0001).

INTERPRETATION

Our findings confirm that medical treatment substantially reduces the risk of early recurrent stroke after TIA and minor stroke and identify aspirin as the key intervention. The considerable early benefit from aspirin warrants public education about self-administration after possible TIA. The previously unrecognised effect of aspirin on severity of early recurrent stroke, the diminishing benefit with longer-term use, and the contrasting time course of effects of dipyridamole have implications for understanding mechanisms of action.

FUNDING

Wellcome Trust, the National Institute of Health Research (NIHR) Biomedical Research Centre, Oxford.

Peroxisome proliferator-activated receptor gamma agonists for preventing recurrent stroke and other vascular events in patients with stroke or transient ischaemic attack

BACKGROUND

Peroxisome proliferator-activated receptor gamma (PPAR-γ) agonists are insulin-sensitising drugs used for the treatment of insulin resistance. In addition to lowering glucose in diabetes, these drugs may also protect against hyperlipidaemia and arteriosclerosis, which are risk factors for stroke.

OBJECTIVES

To assess the efficacy and safety of PPAR-γ agonists in the secondary prevention of stroke and related vascular events for people with stroke or transient ischaemic attack (TIA).

SEARCH METHODS

We searched the Cochrane Stroke Group Trials Register (July 2015), the Cochrane Central Register of Controlled Trials (CENTRAL 2015, Issue 6), MEDLINE (1949 to July 2015), EMBASE (1980 to July 2015), CINAHL (1982 to July 2015), AMED (1985 to July 2015) and 11 Chinese databases (July 2015). In an effort to identify further published, unpublished and ongoing trials we searched ongoing trials registers, reference lists and relevant conference proceedings, and contacted authors and pharmaceutical companies. We did not impose any language restrictions.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) evaluating PPAR-γ agonists versus placebo for the secondary prevention of stroke and related vascular events in people with stroke or TIA, with the outcomes of recurrent stroke, vascular events and adverse events.

DATA COLLECTION AND ANALYSIS

Two review authors independently screened the titles and abstracts of identified records, selected studies for inclusion, extracted eligible data, cross-checked the data for accuracy, and assessed methodological quality and risk of bias.

MAIN RESULTS

We identified four eligible studies with 1163 participants; only one study had a low risk of bias for all domains. Three studies evaluated the drug pioglitazone and one study evaluated rosiglitazone. The participants in different studies were heterogeneous. The number of participants with recurrent stroke was evaluated in two studies, where PPAR-γ agonists reduced the recurrence of stroke compared with placebo (risk ratio (RR) 0.52, 95% confidence interval (CI) 0.34 to 0.80). PPAR-γ agonists given over a mean duration of 34.5 months in a single trial were found to reduce a composite outcome of total events of cardiovascular death, non-fatal myocardial infarction or non-fatal stroke (RR 0.73, 95% CI 0.54 to 0.99). Data on additional composite outcomes reflecting serious adverse events (all-cause death and other major vascular events; all-cause mortality, non-fatal myocardial infarction or non-fatal stroke) were similar although the confidence intervals were wider and the effects were not statistically significant. In addition, two studies respectively measured insulin sensitivity and the ubiquitin-proteasome activity in carotid plaques. These results were significantly improved by PPAR-γ agonists in comparison with placebo. None of the studies reported the number of participants with disability due to vascular events or improvement in quality of life. Three RCTs reported information about adverse events. Frequent adverse events included oedema, cardiac failure and anaemia. Evidence that adverse events occurred more frequently in participants treated with PPAR-γ agonists when compared with placebo was imprecise and inconsistent (risk difference (RD) 10%, 95% CI -8% to 28%, I² = 86%).

AUTHORS' CONCLUSIONS

PPAR-γ agonists appear to reduce recurrent stroke and total events of cardiovascular death, non-fatal myocardial infarction or non-fatal stroke, and improve insulin sensitivity and the stabilisation of carotid plaques. There is evidence of limited quality that they are well tolerated. However, the conclusions should be interpreted with caution considering the small number and the quality of the included studies. In future, well-designed, double-blind RCTs with large samples are required to assess the efficacy and safety of PPAR-γ agonists in the secondary prevention of stroke and related vascular events in people with stroke or TIA.

Peroxisome proliferator-activated receptor gamma agonists for preventing recurrent stroke and other vascular events in patients with stroke or transient ischaemic attack

BACKGROUND

Peroxisome proliferator-activated receptor gamma (PPAR-γ) agonists are insulin-sensitising drugs used for the treatment of insulin resistance. In addition to lowing glucose in diabetes, these drugs may also protect against hyperlipidaemia and arteriosclerosis, which are risk factors for stroke.

OBJECTIVES

To assess the efficacy and safety of PPAR-γ agonists in the secondary prevention of stroke and related vascular events for people with stroke or transient ischaemic attack (TIA).

SEARCH METHODS

We searched the Cochrane Stroke Group Trials Register (August 2013), the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library 2013, Issue 9), MEDLINE (1949 to October 2013), EMBASE (1980 to October 2013), CINAHL (1982 to October 2013), AMED (1985 to October 2013) and 11 Chinese databases (October 2013). In an effort to identify further published, unpublished and ongoing trials we searched ongoing trials registers, reference lists and relevant conference proceedings, and contacted authors and pharmaceutical companies. There were no language restrictions.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) evaluating PPAR-γ agonists versus placebo for the secondary prevention of stroke and related vascular events in people with stroke or TIA, with the outcomes of recurrent stroke, vascular events and adverse events.

DATA COLLECTION AND ANALYSIS

Two review authors independently screened the titles and abstracts of identified records, selected studies for inclusion, extracted eligible data, cross-checked the data for accuracy and assessed the methodological quality.

MAIN RESULTS

We identified four eligible studies with 1163 participants; only one study had a low risk of bias for all domains. The participants in different studies were heterogeneous. The number of participants with recurrent stroke was evaluated in two studies, where PPAR-γ agonists reduced the recurrence of stroke compared with placebo (risk ratio (RR) 0.52, 95% confidence interval (CI) 0.34 to 0.80). PPAR-γ agonists given over a mean duration of 34.5 months in a single trial were found to reduce a composite outcome of total events of cardiovascular death, non-fatal myocardial infarction or non-fatal stroke (RR 0.73, 95% CI 0.54 to 0.99). Data on additional composite outcomes reflecting serious adverse events (all-cause death and other major vascular events; all-cause mortality, non-fatal myocardial infarction or non-fatal stroke) were similar although the confidence intervals were wider and the effects were not statistically significant. In addition, two studies respectively measured insulin sensitivity and the ubiquitin-proteasome activity in carotid plaques with significant differences in these outcomes between PPAR-γ agonists and placebo. None of the studies reported the number of participants with disability due to vascular events or improvement in quality of life. Three RCTs reported information about adverse events. Frequent adverse events included oedema, cardiac failure and anaemia. Evidence that adverse events occurred more frequently in participants treated with PPAR-γ agonists when compared with placebo was imprecise and inconsistent (risk difference (RD) 10%, 95% CI -8% to 28%, I² = 86%).

AUTHORS' CONCLUSIONS

PPAR-γ agonists were demonstrated to reduce recurrent stroke and total events of cardiovascular death, non-fatal myocardial infarction or non-fatal stroke, and improve insulin sensitivity and the stabilisation of carotid plaques. There is evidence of limited quality that they are well-tolerated. However, the conclusions should be interpreted with caution considering the small number and the quality of the included studies. In future, well-designed, double-blind RCTs with large samples are required to test the efficacy and safety of PPAR-γ agonists in the secondary prevention of stroke and related vascular events in people with stroke or TIA.

The current management of carotid atherosclerotic disease: who, when and how?

Ischaemic stroke represents a major health hazard in the western world, which has a severe impact on society and the health-care system. Roughly, 10% of all first ischaemic strokes can be attributed to significant atherosclerotic disease of the carotid arteries. Correct management of these lesions is essential in the prevention and treatment of carotid disease-related ischaemic events. The close relationship between diagnosis and medical and surgical management makes it necessary that all involved physicians and surgeons have profound knowledge of management strategies beyond their specific speciality. Continuous improvement in pharmacological therapy and operative techniques as well as frequently changing guidelines represent a constant challenge for the individual health-care professional. This review gives a thorough outline of the up-to-date evidence-based management of carotid artery disease and discusses its current controversies.

Vitamin K antagonists versus antiplatelet therapy after transient ischaemic attack or minor ischaemic stroke of presumed arterial origin

BACKGROUND

People who have had a transient ischaemic attack (TIA) or non-disabling ischaemic stroke have an annual risk of major vascular events of between 4% and 11%. Aspirin reduces this risk by 20% at most. Secondary prevention trials after myocardial infarction indicate that treatment with vitamin K antagonists is associated with a risk reduction approximately twice that of treatment with antiplatelet therapy.

OBJECTIVES

To compare the efficacy and safety of vitamin K antagonists and antiplatelet therapy in the secondary prevention of vascular events after cerebral ischaemia of presumed arterial origin.

SEARCH METHODS

We searched the Cochrane Stroke Group Trials Register (last searched 15 September 2011), the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library 2011, Issue 3), MEDLINE (2008 to September 2011) and EMBASE (2008 to September 2011). In an effort to identify further relevant trials we searched ongoing trials registers and reference lists. We also contacted authors of published trials for further information and unpublished data.

SELECTION CRITERIA

Randomised trials of oral anticoagulant therapy with vitamin K antagonists (warfarin, phenprocoumon or acenocoumarol) versus antiplatelet therapy for long-term secondary prevention after recent transient ischaemic attack or minor ischaemic stroke of presumed arterial origin.

DATA COLLECTION AND ANALYSIS

Two review authors independently selected trials, assessed trial quality and extracted data.

MAIN RESULTS

We included eight trials with a total of 5762 participants. The data showed that anticoagulants (in any intensity) are not more efficacious in the prevention of vascular events than antiplatelet therapy (medium intensity anticoagulation: relative risk (RR) 0.80, 95% confidence interval (CI) 0.56 to 1.14; high intensity anticoagulation: RR 1.02, 95% CI 0.49 to 2.13). There is no evidence that treatment with low intensity anticoagulation gives a higher bleeding risk than treatment with antiplatelet agents: RR 1.27 (95% CI 0.79 to 2.03). However, it was clear that medium and high intensity anticoagulation with vitamin K antagonists, with an INR of 2.0 to 4.5, were not safe because they yielded a higher risk of major bleeding complications (medium intensity anticoagulation: RR 1.93, 95% CI 1.27 to 2.94; high intensity anticoagulation: RR 9.0, 95% CI 3.9 to 21).

AUTHORS' CONCLUSIONS

For the secondary prevention of further vascular events after TIA or minor stroke of presumed arterial origin, there is sufficient evidence to conclude that vitamin K antagonists in any dose are not more efficacious than antiplatelet therapy and that medium and high intensity anticoagulation leads to a significant increase in major bleeding complications.

Antiplatelet drugs: Antithrombotic Therapy and Prevention of Thrombosis, 9th ed: American College of Chest Physicians Evidence-Based Clinical Practice Guidelines

The article describes the mechanisms of action, pharmacokinetics, and pharmacodynamics of aspirin, dipyridamole, cilostazol, the thienopyridines, and the glycoprotein IIb/IIIa antagonists. The relationships among dose, efficacy, and safety are discussed along with a mechanistic overview of results of randomized clinical trials. The article does not provide specific management recommendations but highlights important practical aspects of antiplatelet therapy, including optimal dosing, the variable balance between benefits and risks when antiplatelet therapies are used alone or in combination with other antiplatelet drugs in different clinical settings, and the implications of persistently high platelet reactivity despite such treatment.

Antithrombotics for secondary prevention of noncardioembolic ischaemic stroke

Antiplatelet therapy is more effective than anticoagulation for the prevention of noncardioembolic ischaemic stroke. The choice of antiplatelet regimen, however, remains contentious. Recent controversies regarding aspirin resistance and the optimal dosing of aspirin, as well as recognition of the variable bioactivation of clopidogrel, have added further confusion to the debate. The American Heart Association (AHA) and American Stroke Association (ASA) recently released their third joint guideline in the past 5 years on secondary stroke prevention. The European Stroke Organisation has published three guidelines on this issue since 2000. These frequent updates have been necessary because of rapidly accumulating data from clinical trials. Careful consideration of the sometimes confusing trial results reveals that the 2011 AHA-ASA guidelines are correct in no longer specifying a 'preferred' antiplatelet regimen from among the choices recently studied. This recommendation does not, however, mean that all antiplatelet regimens should be considered equal. This Review discusses the various antiplatelet regimens, and the trials that led to the rapid evolution of the guidelines for secondary prevention of ischaemic stroke.

Antithrombotic and thrombolytic therapy for ischemic stroke: Antithrombotic Therapy and Prevention of Thrombosis, 9th ed: American College of Chest Physicians Evidence-Based Clinical Practice Guidelines

OBJECTIVES

This article provides recommendations on the use of antithrombotic therapy in patients with stroke or transient ischemic attack (TIA).

METHODS

We generated treatment recommendations (Grade 1) and suggestions (Grade 2) based on high (A), moderate (B), and low (C) quality evidence.

RESULTS

In patients with acute ischemic stroke, we recommend IV recombinant tissue plasminogen activator (r-tPA) if treatment can be initiated within 3 h (Grade 1A) or 4.5 h (Grade 2C) of symptom onset; we suggest intraarterial r-tPA in patients ineligible for IV tPA if treatment can be initiated within 6 h (Grade 2C); we suggest against the use of mechanical thrombectomy (Grade 2C) although carefully selected patients may choose this intervention; and we recommend early aspirin therapy at a dose of 160 to 325 mg (Grade 1A). In patients with acute stroke and restricted mobility, we suggest the use of prophylactic-dose heparin or intermittent pneumatic compression devices (Grade 2B) and suggest against the use of elastic compression stockings (Grade 2B). In patients with a history of noncardioembolic ischemic stroke or TIA, we recommend long-term treatment with aspirin (75-100 mg once daily), clopidogrel (75 mg once daily), aspirin/extended release dipyridamole (25 mg/200 mg bid), or cilostazol (100 mg bid) over no antiplatelet therapy (Grade 1A), oral anticoagulants (Grade 1B), the combination of clopidogrel plus aspirin (Grade 1B), or triflusal (Grade 2B). Of the recommended antiplatelet regimens, we suggest clopidogrel or aspirin/extended-release dipyridamole over aspirin (Grade 2B) or cilostazol (Grade 2C). In patients with a history of stroke or TIA and atrial fibrillation we recommend oral anticoagulation over no antithrombotic therapy, aspirin, and combination therapy with aspirin and clopidogrel (Grade 1B).

CONCLUSIONS

These recommendations can help clinicians make evidence-based treatment decisions with their patients who have had strokes.

Polyvascular atherosclerotic disease: recognizing the risks and managing the syndrome

BACKGROUND

Patients with an initial ischemic event secondary to atherosclerosis have an increased risk of suffering a recurrent event not only in the same vascular territory, but in other territories as well. Patients with polyvascular disease, or atherosclerotic disease in more than one vascular territory, have worse clinical outcomes than those with disease in a single vascular territory. This suggests that atherosclerosis should be treated as a systemic disease with appropriately aggressive secondary preventive measures in order to prevent recurrent events throughout the arterial tree.

OBJECTIVE

To discuss relevant findings for the management of patients with polyvascular disease and provide guidance to clinicians who may not be aware of how best to manage these patients.

METHODS

Relevant English-language articles published from 1950 through February 2009 were identified by searching the Cochrane, MEDLINE, and Ovid databases using the terms 'atherosclerosis,' 'atherothrombosis,' 'cerebrovascular disease,' 'coronary artery disease,' 'cross-risk,' 'management guidelines,' 'peripheral arterial disease,' 'polyvascular,' and 'secondary prevention' either singly or in combination.

FINDINGS AND CONCLUSIONS

According to limited data from patient registries, anywhere from 15% to 30% of patients with atherosclerosis present with disease in multiple vascular territories and experience significantly greater rates of adverse cardiovascular events. Despite these findings, a search of the literature reveals a lack of studies comprised of patients with polyvascular disease only and very few reports on the results of patients with polyvascular disease enrolled in existing secondary prevention studies. Although any conclusions are limited by this small number of studies, clinicians typically treat only the initially affected territory without consideration of the other affected territories and may lack awareness of the overall atherothrombotic syndrome. In the future, clinical trials focused specifically on patients with polyvascular disease should be conducted in order to increase our knowledge on how to manage these patients. Evidence-based clinical practice guidelines are also necessary to improve the management of patients with polyvascular disease.

Aspirin resistance

The development of adverse cardiovascular events despite aspirin use has established an interest in a possible resistance to the drug. Several definitions have been set and various laboratory testing modalities are available. This has led to a wide range of prevalence reports in different clinical entities. The etiologic mechanism has been related to clinical, genetic, and other miscellaneous factors. The clinical implications of this phenomenon are significant and warrant concern. Management strategies are currently limited to dosing alteration and introduction of other anitplatelet agents. However, these measures have not met the expected efficacy or safety.

Antiplatelet drugs in cardiological practice: established strategies and new developments

A common pathophysiological course in vascular diseases is an overwhelming activation and aggregation of blood platelets, which results in atherothrombosis. By causing the last decisive step of cerebral, coronary, or peripheral arterial ischemia thrombotic complications of atherosclerotic disease represent a major player in death cause statistics of most western countries. The development of novel therapies against platelet-dependent thrombosis and the concurrent improvement of existing therapeutic strategies thus is a paramount focus of pharmaceutical research. Currently, efficiency, dosing and indications of established antiplatelet substances are being re-evaluated, whilst new, so far unrecognized molecular targets for inhibition of platelet activity come up front. This not only allows for interesting new therapeutical options, but also widens our insight into the role platelets play in atherosclerosis in general. This article summarizes the relevant pathophysiology of platelet activation, presents current concepts in antiplatelet drug therapy, and highlights the role of platelets in vascular diseases apart from atherothrombosis.

The role of aspirin in cardiovascular prevention: implications of aspirin resistance

Aspirin is well recognized as an effective antiplatelet drug for secondary prevention in subjects at high risk of cardiovascular events. However, most patients receiving long-term aspirin therapy still remain at substantial risk of thrombotic events due to insufficient inhibition of platelets, specifically via the thromboxane A2 pathway. Although the exact prevalence is unknown, estimates suggest that between 5.5% and 60% of patients using this drug may exhibit a degree of "aspirin resistance," depending upon the definition used and parameters measured. To date, only a limited number of clinical studies have convincingly investigated the importance of aspirin resistance. Of these, few are of a sufficient scale, well designed, and prospective, with aspirin used at standard doses. Also, most studies do not sufficiently address the issue of noncompliance to aspirin as a frequent, yet easily preventable cause of resistance to this antiplatelet drug. This review article provides a comprehensive overview of aspirin resistance, discussing its definition, prevalence, diagnosis, and therapeutic approaches. Moreover, the clinical implications of aspirin resistance are explored in various cardiovascular disease states, including diabetes mellitus, hypertension, heart failure, and other similar disorders where platelet reactivity is enhanced.