MR Perfusion in the Evaluation of Mechanical Thrombectomy Candidacy

Contrast conservation measures during the global iohexol contrast shortage crisis did not affect stroke thrombectomy outcomes

BACKGROUND

The current global shortage in iohexol contrast material (Omnipaque) used in performing CT-based triage images and mechanical thrombectomy (MT) represents a challenge to the healthcare system. A study was undertaken to assess the safety and feasibility of implementing protocol-based changes in pre-MT and MT workflow at a comprehensive stroke center.

METHODS

A retrospective cohort study was undertaken of all patients with stroke who underwent MT during a 3-week period before implementing the contrast shortage protocol and for 3 weeks while implementing the protocol. The contrast shortage protocol included not performing perfusion images for MT selection and using diluted iohexol (50% contrast mixed with 50% heparinized saline) during the MT procedure. Procedural variables were compared between the two groups.

RESULTS

A total of 27 patients underwent MT during the study period, 12 pre-contrast shortage and 15 post-contrast shortage. The average contrast volume used during the MT procedure was reduced from 83 mL to 68 mL after implementing the contrast shortage protocol (p=0.04). No difference was noted in the rate of successful reperfusion (11/15 vs 10/12), average time to recanalization (21 vs 23 min), average radiation dose (1143 vs 1117mGy) and time under fluoroscopy (20.7 vs 20.5 min) in the pre- and post-contrast shortage groups. A favorable discharge outcome was observed in 3/12 patients and 4/15 patients in the pre- and post-shortage periods, respectively (p=0.92).

CONCLUSIONS

Modifying stroke workflow to adapt to the current global shortage in iohexol is feasible. Using diluted iohexol (50% contrast mixed with 50% heparinized saline) did not affect MT outcomes.

Translational Stroke Research Review: Using the Mouse to Model Human Futile Recanalization and Reperfusion Injury in Ischemic Brain Tissue

The approach to reperfusion therapies in stroke patients is rapidly evolving, but there is still no explanation why a substantial proportion of patients have a poor clinical prognosis despite successful flow restoration. This issue of futile recanalization is explained here by three clinical cases, which, despite complete recanalization, have very different outcomes. Preclinical research is particularly suited to characterize the highly dynamic changes in acute ischemic stroke and identify potential treatment targets useful for clinical translation. This review surveys the efforts taken so far to achieve mouse models capable of investigating the neurovascular underpinnings of futile recanalization. We highlight the translational potential of targeting tissue reperfusion in fully recanalized mouse models and of investigating the underlying pathophysiological mechanisms from subcellular to tissue scale. We suggest that stroke preclinical research should increasingly drive forward a continuous and circular dialogue with clinical research. When the preclinical and the clinical stroke research are consistent, translational success will follow.