Letter to the Editor. Flow Diversion in the Treatment of Intracranial Aneurysm Trial

Flow Diversion in the Treatment of Intracranial Aneurysms: A Pragmatic Randomized Care Trial

BACKGROUND AND PURPOSE

Flow diversion is a recent endovascular treatment for intracranial aneurysms. We compared the safety and efficacy of flow diversion with the alternative standard management options.

MATERIALS AND METHODS

A parallel group, prerandomized, controlled, open-label pragmatic trial was conducted in 3 Canadian centers. The trial included all patients considered for flow diversion. A Web-based platform 1:1 randomly allocated patients to flow diversion or 1 of 4 alternative standard management options (coiling with/without stent placement, parent vessel occlusion, surgical clipping, or observation) as prespecified by clinical judgment. Patients ineligible for alternative standard management options were treated with flow diversion in a registry. The primary safety outcome was death or dependency (mRS > 2) at 3 months. The composite primary efficacy outcome included the core lab-determined angiographic presence of a residual aneurysm, aneurysm rupture, progressive mass effect during follow-up, or death or dependency (mRS > 2) at 3-12 months.

RESULTS

Between May 2011 and November 2020, three hundred twenty-three patients were recruited: Two hundred seventy-eight patients (86%) had treatment randomly allocated (139 to flow diversion and 139 to alternative standard management options), and 45 (14%) received flow diversion in the registry. Patients in the randomized trial frequently had unruptured (83%), large (52% ≥10 mm) carotid (64%) aneurysms. Death or dependency at 3 months occurred in 16/138 patients who underwent flow diversion and 12/137 patients receiving alternative standard management options (relative risk, 1.33; 95% CI, 0.65-2.69; P = .439). A poor primary efficacy outcome was found in 30.9% (43/139) with flow diversion and 45.6% (62/136) of patients receiving alternative standard management options, with an absolute risk difference of 14.7% (95% CI, 3.3%-26.0%; relative risk, 0.68; 95% CI, 0.50-0.92; P = .014).

CONCLUSIONS

For patients with mostly unruptured, large, anterior circulation (carotid) aneurysms, flow diversion was more effective than the alternative standard management option in terms of angiographic outcome.

Unruptured aneurysms: Why observational studies fall short no matter how "Big" the Data

BACKGROUND

The best management of unruptured intracranial aneurysms (UIAs) remains unknown, despite multiple observational studies. A randomized trial (RCT) is in order. Yet, a National Institute Neurological Disorders and Stroke workshop has once again proposed to use prospective observational studies (POS) of large databases to address such problems.

METHODS

We review the historical misconceptions that have been associated with observations of UIAs and their treatments. We critically examine some recent methods that have been proposed to address shortcomings of observational studies. We finally review the ethical principles underlying the use of trial methods in the care of patients.

RESULTS

Replacing RCTs with POS submits patients to management options that have never been proven beneficial, while making them involuntary research subjects of studies that are inevitably biased. A science of practice cannot be an outsider's examination of the behavior of clinicians incapable of questioning their practice. The thesis we propose is that a science of practice must not only eventually determine what best practice will be; It must engage agents involved in medical practice to transparently reveal the uncertainty that calls for management options to be offered under the guidance of declared and controlled care research, to optimize patient outcomes in spite of the uncertainty.

CONCLUSION

To use POS rather than RCTs in medical practice is to renege on scientific and ethical principles that characterize modern medicine. Instead, we must learn to integrate care research into our practice to provide optimal medical care in real time.

Practicing outcome-based medical care using pragmatic care trials

The current separation between medical research and care is an obstacle to essential aspects of good medical practice: the verification that care interventions actually deliver the good outcomes they promise, and the use of scientific methods to optimize care under uncertainty. Pragmatic care trials have been designed to address these problems. Care trials are all-inclusive randomized trials integrated into care. Every item of trial design is selected in the best medical interest of participating patients. Care trials can eventually show what constitutes good medical practice based on patient outcomes. In the meantime, care trials give clinicians and patients the scientific methods necessary for optimization of medical care when no one really knows what to do.We report the progress of 9 randomized care trials that were used to guide the endovascular or surgical management of 1212 patients with acute stroke, intracranial aneurysms, and arteriovenous malformations in a single center in an elective or acute care context. Care trials were used to address long-standing dilemmas regarding rival medical, surgical, or endovascular management options or to offer innovative instead of standard treatments. The trial methodology, by replacing unrepeatable treatment decisions by 1:1 randomized allocation whenever reliable knowledge was not available, had an immediate impact, transforming unverifiable dogmatic medical practice into verifiable outcome-based medical care. We believe the approach is applicable to all medical or surgical domains, but widespread adoption may require the revision of many currently prevalent views regarding the role of research in clinical practice.

The 2018 ter Brugge Lecture: Problems with the Introduction of Innovations in Neurovascular Care

Most endovascular innovations have been introduced into clinical care by showing good outcomes in small enthusiastic case series of selected patients. Randomized clinical trials (RCTs) have rarely been performed, except for acute ischemic stroke, but even then most trial designs were too explanatory to inform clinical decisions. In this article, we review 2 × 2 tables and forest plots that summarize RCT results to examine methodological issues in the design and interpretation of clinical studies. Research results can apply in practice when RCTs are all-inclusive, pragmatic trials. Common problems include the following: (i) using restrictive eligibility criteria in explanatory trials, instead of including the diversity of patients in need of care, which hampers future generalizability of results; (ii) ignoring an entire line of the 2 × 2 table and excluding patients who do not meet the proposed criteria of a diagnostic test in its evaluation (perfusion studies) which renders clinical inferences misleading; (iii) ignoring an entire column of the 2 × 2 table and comparing different patients treated using the same treatment instead of different treatments in the same patients (the "wrong axis" comparisons of prognostic studies and clinical experience) which leads to unjustified treatment decisions and actions; or (iv) combining all aforementioned problems (case series and epidemiological studies). The most efficient and reliable way to improve patient outcomes, after as well as long before research results are available, is to change the way we practice: to use care trials to guide care in the presence of uncertainty.