A dual-center validation of the PIRAMD scoring system for assessing the severity of ischemic Moyamoya disease

Background

Prior Infarcts, Reactivity, and Angiography in Moyamoya Disease (PIRAMD) is a recently proposed imaging-based scoring system that incorporates the severity of disease and its impact on parenchymal hemodynamics in order to better support clinical management and evaluate response to intervention. In particular, PIRAMD may have merit in identifying symptomatic patients that may benefit most from revascularization. Our aim was to validate the PIRAMD scoring system.

Methods

Patients with ischemic Moyamoya disease, who underwent catheter angiographic [modified Suzuki Score (mSS) and collateralization status], morphological MRI and a parenchymal hemodynamic evaluation with blood oxygenation-level dependent cerebrovascular reactivity (BOLD-CVR) at two transatlantic centers, were retrospectively included. The primary outcome was the presence of neurological symptoms. The diagnostic capacity of each PIRAMD feature alone was evaluated, as well as combined and the inter-institutional differences of each parameter were evaluated.

Results

Seventy-two hemispheres of 38 patients were considered for analysis, of which 39 (54%) were classified as symptomatic. The presence of a prior infarct had the highest odds ratio [odds ratio (OR) =24; 95% CI: 6.7-87.2] for having neurological symptoms, followed by impaired CVR (OR =17; 95% CI: 5-62). No inter-institutional differences in the odds ratios or area under the curve (AUC) were found for any study parameter. The PIRAMD score had an AUC of 0.88 (95% CI: 0.80-0.96) with a similar AUC for the PIRAMD grading score.

Conclusions

Our multicentric validation of the recently published PIRAMD scoring system was highly effective in rating the severity of ischemic Moyamoya disease with excellent inter-institutional agreement. Future studies should investigate the prognostic value of this novel imaging-based score in symptomatic patients with Moyamoya disease.

Understanding the difference between theory and practice: The extracranial-intracranial bypass trials in prevention of ischemic stroke

BACKGROUND

Patients with atherosclerotic carotid or middle cerebral artery occlusions suffer ischemic events that might theoretically be preventable with a surgical extracranial-intracranial bypass, but theory by itself does not justify surgical interventions.

METHODS

We review landmark randomized trials on EC-IC bypass surgery for the treatment of ischemic stroke in patients with atherosclerotic stenoses or occlusions.

RESULTS

The initial EC-IC bypass trial from 1985 did not show any clinical benefit from surgery. The carotid occlusion surgery study (COSS) performed more than 20 years later included only patients highly selected to potentially benefit from bypass by using modern perfusion studies. While EC-IC bypasses were successfully created and they did improve cerebral perfusion, the COSS study also failed to show any clinical benefit to the participating patients.

CONCLUSION

Neurosurgical interventions must not only work in theory; they must improve patient outcomes in real practice.

Understanding how the primary endpoint impacts the interpretation of trial results: The Japanese Adult Moyamoya bypass trial

BACKGROUND

The meaning of a clinical trial depends to a large extent on the choice of the primary outcome measure, which can be explanatory or pragmatic.

METHODS

We review the Japanese Adult Moyamoya (JAM) trial, that compared surgical extracranial to intracranial (EC-IC) bypass and medical management of hemorrhagic moyamoya disease. We also review some principles which guide the selection of the primary trial endpoint.

DISCUSSION

The main component of the primary outcome measure in JAM was rebleeding, a surrogate outcome that allowed investigators to demonstrate that surgical bypass had causal efficacy. However, the number of patients with a poor outcome, defined as those with a modified Rankin score (mRS)>2, would have been a more pragmatic choice. Unfortunately, the trial was too small to show that patients benefited from surgery.

CONCLUSION

The JAM trial showed that EC-IC bypass can decrease rebleeding in moyamoya patients, but whether patients have better outcomes with surgery remains uncertain. Hard pragmatic clinical primary outcome measures are necessary to guide surgical care.

Recruitment in a pragmatic randomized trial on the management of unruptured intracranial aneurysms

OBJECTIVES

The Comprehensive Aneurysm Management (CAM) study is a pragmatic trial designed to manage UIA patients within a care research framework.

METHOD

CAM is an all-inclusive study. Management options are allocated according to an algorithm combining pre-randomization and clinical judgment. Eligible patients are offered 1:1 randomized allocation of intervention versus conservative management and 1:1 randomization allocation of surgical versus endovascular treatment. Ineligible patients are registered. The primary outcome is survival without dependency (mRS<3) at 10 years. All UIA patients at one center are reported.

RESULTS

Between February 2020 and July 2021, 403 UIA patients were recruited: 179 (44%) in one of the RCTs and 224 (56%) in one of the registries. Conservative management was recommended for 205/403 patients (51%); of 198 (49%) patients considered for curative treatment, 159 (80%) were randomly allocated conservative (n=81) or curative treatment (n=78). These patients were younger and had larger aneurysms than those in the observation registry (P = .004). In 39/198 patients (20%), conservative management was not considered reasonable (17 patients were recommended endovascular, 2 surgery, and 20 the RCT comparing endovascular with surgical treatment). In total, 70 patients were recruited in the RCT comparing surgery and endovascular treatment. After informed discussion at time of consent, 141/159 patients (89%) agreed with the randomly allocated management plan, while 11% crossed-over to the alternative management option.

CONCLUSION

CAM was successfully integrated into routine practice. Meaningful conclusions can be obtained if multiple centers actively participate in the trial.