Symptomatic Intracranial Hemorrhage after Mechanical Thrombectomy - the Difference between Iso-Osmolar and Low-Osmolar Contrast Media

Abstract

Objective: Symptomatic intracranial hemorrhage (SICH) after mechanical thrombectomy (MT) is generally considered a critical complication. Hemorrhagic transformation after ischemic stroke has also been associated with contrast media administration. The objective of our study was to evaluate correlations between contrast media type and incidence of SICH after MT.

Methods: Ninety-three consecutive patients (41 men; mean age, 80.2 years; range, 44-98 years) underwent MT reperfusion (expanded thrombolysis in cerebral infarction score, 2a-3) for acute large-vessel occlusion ischemic stroke within 8 h after symptom onset between April 2020 and July 2023 were retrospectively reviewed. Correlations between contrast media type (iso-osmolar or low-osmolar medium) and incidence of SICH were assessed.

Results: Contrast media were iso-osmolar in 60 cases or low-osmolar in 33 cases. The overall incidence of SICH was 5.5%. The frequency of SICH was significantly lower in the iso-osmolar group (1.7%) than in the low-osmolar group (12.1%; P = 0.033).

Conclusion: Iso-osmolar contrast media was associated with a lower incidence of SICH compared with low-osmolar contrast media in patients after MT.

Keywords: iso-osmolar contrast media; mechanical thrombectomy; symptomatic intracranial hemorrhage.

Fig. 1. Flow chart for patients who underwent MT for acute ischemic stroke. eTICI: expanded thrombolysis in cerebral infarction; IOCM: iso-osmolar contrast media; LOCM: low-osmolar contrast media; MT, mechanical thrombectomy

Fig. 2. A 71-year-old female presented to our hospital with a 5-h history of left-sided weakness. The NIHSS score at the time of admission was 6. (A, B, and C) MRI diffusion imaging before treatment shows mild hyperintensity area suspected acute ischemic lesions in the right frontal lobe and insular cortex. (D) MRA shows the M2 occlusion of the right MCA (arrow). She underwent stent retriever thrombectomy combined with aspiration catheter therapy following admission. (E) Anteroposterior DSA image before treatment reveals the M2 anterior trunk occlusion of the right MCA (arrow). (F) DSA using a simultaneous injection of contrast media (LOCM) from the microcatheter and from the guiding catheter shows a thrombus in the M2 anterior trunk (small arrows). (G) A 4 × 40 mm Solitaire stent is placed into the M2 anterior trunk for MT (small arrows). (H) Final anteroposterior DSA image shows complete recanalization (eTICI 3) of the right MCA. (I) The Solitaire stent is covered with fresh clots. (J) Head CT at 1 h after MT shows relative high density in the right frontal lobe and right lenticular nucleus, indicating contrast staining. However, at 6 h after MT, she had loss of consciousness and the NIHSS score at the time was 10 (increased by 4 compared to immediately before worsening). (K) Head CT at 6 h after MT shows large hemorrhagic lesions in the right cerebral hemisphere with a significant mass effect. An emergent surgical decompression was performed but the patient’s level of consciousness did not improve (mRS 4). eTICI: expanded thrombolysis in cerebral infarction; LOCM: low-osmolar contrast media; MCA: middle cerebral artery; mRS: modified Rankin Scale; MT: mechanical thrombectomy;.NIHSS: National Institutes of Health Stroke Scale