Assessment of the End Point Adjudication Process on the Results of the Platelet-Oriented Inhibition in New TIA and Minor Ischemic Stroke (POINT) Trial: A Secondary Analysis

Endpoint adjudication in cardiovascular clinical trials

Endpoint adjudication (EA) is a common feature of contemporary randomized controlled trials (RCTs) in cardiovascular medicine. Endpoint adjudication refers to a process wherein a group of expert reviewers, known as the clinical endpoint committee (CEC), verify potential endpoints identified by site investigators. Events that are determined by the CEC to meet pre-specified trial definitions are then utilized for analysis. The rationale behind the use of EA is that it may lessen the potential misclassification of clinical events, thereby reducing statistical noise and bias. However, it has been questioned whether this is universally true, especially given that EA significantly increases the time, effort, and resources required to conduct a trial. Herein, we compare the summary estimates obtained using adjudicated vs. non-adjudicated site designated endpoints in major cardiovascular RCTs in which both were reported. Based on these data, we lay out a framework to determine which trials may warrant EA and where it may be redundant. The value of EA is likely greater when cardiovascular trials have nuanced primary endpoints, endpoint definitions that align poorly with practice, sub-optimal data completeness, greater operator variability, and lack of blinding. EA may not be needed if the primary endpoint is all-cause death or all-cause hospitalization. In contrast, EA is likely merited for more nuanced endpoints such as myocardial infarction, bleeding, worsening heart failure as an outpatient, unstable angina, or transient ischaemic attack. A risk-based approach to adjudication can potentially allow compromise between costs and accuracy. This would involve adjudication of a small proportion of events, with further adjudication done if inconsistencies are detected.

Using the PEAR1 Polymorphisms Rs12041331 and Rs2768759 as Potential Predictive Markers of 90-Day Bleeding Events in the Context of Minor Strokes and Transient Ischemic Attack

In this study, we explored the relationship between the platelet endothelial aggregation receptor 1 (PEAR1) polymorphisms, platelet reactivity, and clinical outcomes in patients with minor stroke or transient ischemic attack (TIA). Randomized controlled trial subgroups were assessed, wherein patients received dual antiplatelet therapy for at least 21 days. Platelet reactivity was measured at different time intervals. Genotypes were categorized as wild-type, mutant heterozygous, and mutant homozygous. Clinical outcomes were evaluated after 90 days. The rs12041331 polymorphism predominantly influenced adenosine diphosphate channel platelet activity, with the AA genotype displaying significantly lower residual platelet activity to the P2Y12 response unit (p < 0.01). This effect was more evident after 7 days of dual antiplatelet treatment (p = 0.016). Mutant A allele carriers had decreased rates of recurrent stroke and complex endpoint events but were more prone to bleeding (p = 0.015). The rs2768759 polymorphism majorly impacted arachidonic acid (AA) channel platelet activity, which was particularly noticeable in the C allele carriers. Our regression analysis demonstrated that rs12041331 AA + GA and rs2768759 CA predicted 90-day post-stroke bleeding. In conclusion, the PEAR1 polymorphisms rs12041331 and rs2768759 interfere with platelet aggregation and the performance of antiplatelet drugs. These genetic variations may contribute to bleeding events associated with minor stroke and TIA.

Leveraging electronic health records to streamline the conduct of cardiovascular clinical trials

Conventional randomized controlled trials (RCTs) can be expensive, time intensive, and complex to conduct. Trial recruitment, participation, and data collection can burden participants and research personnel. In the past two decades, there have been rapid technological advances and an exponential growth in digitized healthcare data. Embedding RCTs, including cardiovascular outcome trials, into electronic health record systems or registries may streamline screening, consent, randomization, follow-up visits, and outcome adjudication. Moreover, wearable sensors (i.e. health and fitness trackers) provide an opportunity to collect data on cardiovascular health and risk factors in unprecedented detail and scale, while growing internet connectivity supports the collection of patient-reported outcomes. There is a pressing need to develop robust mechanisms that facilitate data capture from diverse databases and guidance to standardize data definitions. Importantly, the data collection infrastructure should be reusable to support multiple cardiovascular RCTs over time. Systems, processes, and policies will need to have sufficient flexibility to allow interoperability between different sources of data acquisition. Clinical research guidelines, ethics oversight, and regulatory requirements also need to evolve. This review highlights recent progress towards the use of routinely generated data to conduct RCTs and discusses potential solutions for ongoing barriers. There is a particular focus on methods to utilize routinely generated data for trials while complying with regional data protection laws. The discussion is supported with examples of cardiovascular outcome trials that have successfully leveraged the electronic health record, web-enabled devices or administrative databases to conduct randomized trials.

Should we adjudicate outcomes in stroke trials? A systematic review

BACKGROUND

Central adjudication of outcomes is common in randomized clinical trials in stroke. The rationale for adjudication is clear; centrally adjudicated outcomes should have less random and systematic errors than outcomes assessed locally by site investigators. However, adjudication brings added complexities to a clinical trial and can be costly.

AIM

To assess the evidence for outcome adjudication in stroke trials.

SUMMARY OF REVIEW

We identified 12 studies evaluating central adjudication in stroke trials. The majority of these were secondary analyses of trials, and the results of all of these would have remained unchanged had central adjudication not taken place, even for trials without sufficient blinding. The largest differences between site-assessed and adjudicator-assessed outcomes were between the most subjective outcomes, such as causality of serious adverse events. We found that the cost of adjudication could be upward of £100,000 for medium to large prevention trials. These findings suggest that the cost of central adjudication may outweigh the advantages it brings in many cases. However, through simulation, we found that only a small amount of bias is required in site investigators' outcome assessments before adjudication becomes important.

CONCLUSION

Central adjudication may not be necessary in stroke trials with blinded outcome assessment. However, for open-label studies, central adjudication may be more important.

Central vs site outcome adjudication in the IRIS trial

BACKGROUND

Central adjudication of outcome events is the standard in clinical trial research. We examine the benefit of central adjudication in the Insulin Resistance Intervention after Stroke (IRIS) trial and show how the benefit is influenced by outcome definition and features of the adjudicated events.

METHODS

IRIS tested pioglitazone for prevention of stroke and myocardial infarction in patients with a recent transient ischemic attack or ischemic stroke. We compared the hazard ratios for study outcomes classified by site and central adjudication. We repeated the analysis for an updated stroke definition.

RESULTS

The hazard ratios for the primary outcome were identical (0.76) and statistically significant regardless of adjudicator. The hazard ratios for stroke alone were nearly identical with site and central adjudication, but only reached significance with site adjudication (HR, 0.80; p = 0.049 vs. HR, 0.82; p = 0.09). Using the updated stroke definition, all hazard ratios were lower than with the original IRIS definition and statistically significant regardless of adjudication method. Agreement was higher when stroke type was certain, subtype was large vessel or cardioembolic, signs or symptoms lasted > 24 h, imaging showed a stroke, and when NIHSS was ≥3.

DISCUSSION

Central stroke adjudication caused the hazard ratio for a main secondary outcome in IRIS (stroke alone) to be higher and lose statistical significant compared with site review. The estimate of treatment effects were larger with the updated stroke definition. There may be benefit of central adjudication for events with specific features, such as shorter symptom duration or normal brain imaging.

Management of Oral Anticoagulation and Antiplatelet Therapy in Post-Myocardial Infarction Patients with Acute Ischemic Stroke with and without Atrial Fibrillation

The association between atrial fibrillation (AF), acute coronary syndrome (ACS), and stroke is a complex scenario in which the assessment of both thrombotic and hemorrhagic risk is necessary for scheduling an individually tailored therapeutic plan. Recent clinical trials investigating new antithrombotic drugs and dual and triple pathways in high-risk cardiovascular patients have revealed a new therapeutic scenario. In this paper, we review the burden of ischemic stroke (IS) in patients post-myocardial infarction with and without atrial fibrillation and the possible therapeutic strategies from a stroke point of view.

P2Y12 inhibitors plus aspirin for acute treatment and secondary prevention in minor stroke and high-risk transient ischemic attack: A systematic review and meta-analysis

BACKGROUND

Aspirin is a cornerstone of preventive treatment for stroke recurrence, but during the last few years the role of dual antiplatelet therapy (DAPT) is much more emerging.

OBJECTIVE

This systematic review aimed to compare early use of P2Y12 inhibitors (clopidogrel/ticagrelor) plus aspirin to aspirin alone for acute treatment and secondary prevention in acute non-cardioembolic minor ischemic stroke or TIA.

METHODS

A systematic search on MEDLINE and EMBASE was performed. Treatment effects were estimated with RRs and 95% CI. We used RevMan 5.4 for data analyses. We assessed methodological quality of selected studies according to Rob2 tools and quality of evidence with GRADE approach.

RESULTS

Four RCTs were included, enrolling 21,459 patients. Compared to aspirin alone, DAPT was superior in reducing stroke recurrence (RR 0.74, 95% CI 0.67-0.82, P <0.00001, absolute risk difference by 2%, NNT 50) and disabling stroke defined as mRS>2 (RR 0.84, 95% CI 0.75-0.95, P = 0.004), with no impact on all causes of mortality (RR 1.30, 95% CI 0.90-1.89, P = 0.16). An increased risk of major bleeding was emerged (RR 2.54, 95% CI 1.65-3.92, P <0.0001, absolute risk difference by 0,4%, NNH 250), in particular with ticagrelor, but there was no correlation between therapy duration and bleeding risk, as appeared from one-month (RR 3.06, 95% CI 1.64 to 5.69) and three-month (RR 2.09, 95% CI 1.18 to 3.69) follow-up analysis.

CONCLUSIONS

Early administration of P2Y12 inhibitors plus aspirin in patients with acute non-cardioembolic minor ischemic stroke or TIA reduced the incidence of ischemic stroke recurrence, impacting more significantly than the increased bleeding risk and influencing patients' quality of life by reducing disabling stroke.

Clinical characteristics, time course, and outcomes of major bleeding according to bleeding site in patients with venous thromboembolism

BACKGROUND

Bleeding is the most dreaded complication of anticoagulant therapy for acute venous thromboembolism (VTE). Limited data exist about patient characteristics, time course and outcomes of major bleeding, according to the bleeding site.

METHODS

We used the data from the Registro Informatizado Enfermedad TromboEmbólica (RIETE) registry (03/2001-07/2018) and identified patients who suffered from major bleeding during anticoagulation. We assessed patient characteristics, time course, and 30-day outcomes including mortality, re-bleeding, and VTE recurrences, according to bleeding site.

RESULTS

Among 78,136 patients with VTE receiving anticoagulation, 2244 (2.9%) suffered from major bleeding (gastrointestinal in 800, intracranial in 417, hematoma in 410, genitourinary in 222, retroperitoneal in 145; other sites in 250). There were variations in baseline characteristics, including older age (P < 0.001) and predominance of women (70.2% [95% confidence interval [CI]]: 65.6-74.6% versus 50.5%, 95% CI: 48.2-52.9, P < 0.001) in patients with hematoma, compared with other patients. Overall, 82.7% of hematomas and 81.4% of retroperitoneal bleeds occurred in the first 90 days after the diagnosis of the VTE event, compared with only 50.6% of intracranial bleeds. Across the bleeding subgroups, 30-day all-cause mortality rates were highest in patients who suffered from intracranial bleeding (41.0%; 99% confidence interval [CI]: 34.8-47.4%), and lowest in patients who suffered from hematoma (17.8%; 99% CI: 13.2-23.2%). Patients who suffered from a major bleeding event in the first 30 days after VTE had significantly higher odds at 90-day follow-up to develop mortality (including from bleeding), recurrent VTE, and recurrent major bleeding (all Ps < 0.001). Variations were observed in the results according to the bleeding site.

CONCLUSIONS

Major bleeding is a serious complication in VTE patients. Patient characteristics, time course and outcomes varied substantially according to the bleeding site. Additional studies are needed to tease out the impact of patient risk factors, treatment regimens, and a potential distinct effect from the site of bleeding.

TRIAL REGISTRATION

https://clinicaltrials.gov/ct2/show/NCT02832245 (RIETE registry).

Comparison of Clinically Adjudicated Versus Flow-Based Adjudication of Revascularization Events in Randomized Controlled Trials

BACKGROUND

In clinical trials, the optimal method of adjudicating revascularization events as clinically or nonclinically indicated (CI) is to use an independent Clinical Events Committee (CEC). However, the Academic Research Consortium-2 currently recommends using physiological assessment. The level of agreement between these methods of adjudication remains unknown.

METHODS

Data for all CEC adjudicated revascularization events among the 3457 patients followed-up for 2-years in the TALENT trial, and 3-years in the DESSOLVE III, PIONEER, and SYNTAX II trial were collected and readjudicated according to a quantitative flow ratio (QFR) analysis of the revascularized vessels, by an independent core lab blinded to the results of the conventional CEC adjudication. The κ statistic was used to assess the level of agreement between the 2 methods.

RESULTS

In total, 351 CEC-adjudicated repeat revascularization events occurred, with retrospective QFR analysis successfully performed in 212 (60.4%). According to QFR analysis, 104 events (QFR ≤0.80) were adjudicated as CI revascularizations and 108 (QFR >0.80) were not. The agreement between CEC and QFR based adjudication was just fair (κ=0.335). Between the 2 methods of adjudication, there was a disagreement of 26.4% and 7.1% in CI and non-CI revascularization, respectively. Overall, the concordance and discordance rates were 66.5% and 33.5%, respectively.

CONCLUSIONS

In this event-level analysis, QFR based adjudication had a relatively low agreement with CEC adjudication with respect to whether revascularization events were CI or not. CEC adjudication appears to overestimate CI revascularization as compared with QFR adjudication. Direct comparison between these 2 strategies in terms of revascularization adjudication is warranted in future trials. Registration: URL: https://www.clinicaltrials.gov; Unique identifier: TALENT trial: NCT02870140, DESSOLVE III trial: NCT02385279, SYNTAX II: NCT02015832, and PIONEER trial: NCT02236975.

The 2020 breakthroughs in early secondary prevention: dual antiplatelet therapy versus single antiplatelet therapy

PURPOSE OF REVIEW

Single antiplatelet therapy represents an established treatment in secondary prevention of ischemic strokes and transient ischemic attacks (TIAs). In contrast with coronary artery disease, the use of dual antiplatelet therapy (DAPT) for secondary prevention in patients with acute cerebral ischemia (ACI) remains under debate. In this narrative review, we present and analyse the most recent findings concerning the potential efficacy and safety of DAPT therapy after ischemic strokes or TIA.

RECENT FINDINGS

Following the publication of the three (CHANCE, POINT and THALES) large, randomized-controlled, clinical trials (RCTs) that showed efficacy of early DAPT for the secondary prevention after minor AIS or TIA, short-term DAPT use is becoming the most prevalent choice of treatment. Notably, DAPT is even more popular after AIS attributed to large artery atherosclerosis given randomized data from small RCTs supporting the use of DAPT in patients with extracranial or intracranial atherosclerosis and microembolization detected by transcranial Doppler. Recent subanalysis of data from the randomized trials aim to identify specific patient subgroups, which are determined by genetic, imaging or clinical characteristics, and for whom DAPT appears to be more beneficial. The potential role of different antiplatelet agents (aspirin, clopidogrel, ticagrelor) is also discussed.

SUMMARY

DAPT has recently proven its efficacy for the early secondary prevention of AIS patients with minor stroke severity and high-risk TIA patients. However, the length of DAPT is still controversial, as well as the individualized selection of AIS or TIA patients with the lower risk of bleeding and with the greater benefit in prevention of ischemic cerebrovascular and cardiovascular events.