Antiplatelet Therapy in Aneurysmal Subarachnoid Hemorrhage

Peroxisome proliferator‑activated receptor β/δ regulates cerebral vasospasm after subarachnoid hemorrhage via modulating vascular smooth muscle cells phenotypic conversion

Cerebral vasospasm (CVS) is a common complication of subarachnoid hemorrhage (SAH) with high deformity rates and cerebral vascular smooth muscle cells (VSMCs) phenotypic switch is considered to be involved in the regulation of CVS. However, to the best of the authors' knowledge, its underlying molecular mechanism remains to be elucidated. Peroxisome proliferator‑activated receptor β/δ (PPARβ/δ) has been demonstrated to be involved in the modulation of vascular cells proliferation and maintains the autoregulation function of blood vessels. The present study investigated the potential effect of PPARβ/δ on CVS following SAH. A model of SAH was established by endovascular perforation on male adult Sprague‑Dawley rats, and the adenovirus PPARβ/δ (Ad‑PPARβ/δ) was injected via intracerebroventricular administration prior to SAH. The expression levels of phenotypic markers α‑smooth muscle actin and embryonic smooth muscle myosin heavy chain were measured via western blotting or immunofluorescence staining. The basilar artery diameter and vessel wall thickness were evaluated under fluorescence microscopy. SAH grade, neurological scores, brain water content and brain swelling were measured to study the mechanisms of PPARβ/δ on vascular smooth muscle phenotypic transformation. It was revealed that the expression levels of synthetic proteins were upregulated in rats with SAH and this was accompanied by CVS. Activation of PPARβ/δ using Ad‑PPARβ/δ markedly upregulated the contractile proteins elevation, restrained the synthetic proteins expression and attenuated SAH‑induced CVS by regulating the phenotypic switch in VSMCs at 72 h following SAH. Furthermore, the preliminary study demonstrated that PPARβ/δ downregulated ERK activity and decreased the expression of phosphorylated (p‑)ETS domain‑containing protein Elk‑1 and p‑p90 ribosomal S6 kinase, which have been demonstrated to serve an important role in VSMC phenotypic change. Additionally, it was revealed that Ad‑PPARβ/δ could positively improve CVS by ameliorating the diameter of the basilar artery and mitigating the thickness of the vascular wall. Furthermore, subsequent experiments demonstrated that Ad‑PPARβ/δ markedly reduced the brain water content and brain swelling and improved the neurological outcome. Taken together, the present study identified PPARβ/δ as a useful regulator for the VSMCs phenotypic switch and attenuating CVS following SAH, thereby providing novel insights into the therapeutic strategies of delayed cerebral ischemia.

The effects of continuous prostacyclin infusion on regional blood flow and cerebral vasospasm following subarachnoid haemorrhage: study protocol for a randomised controlled trial

BACKGROUND

One of the main causes of mortality and morbidity following subarachnoid haemorrhage (SAH) is the development of cerebral vasospasm, a frequent complication arising in the weeks after the initial bleeding. Despite extensive research, to date no effective treatment of vasospasm exists. Prostacyclin is a potent vasodilator and inhibitor of platelet aggregation. In vitro models have shown a relaxing effect of prostacyclin after induced contraction in cerebral arteries, and a recent pilot trial showed a positive effect on cerebral vasospasm in a clinical setting. No randomised, clinical trials have been conducted, investigating the possible pharmacodynamic effects of prostacyclin on the human brain following SAH.

METHODS

This trial is a single-centre, randomised, placebo-controlled, parallel group, blinded, clinical, pilot trial. A total of 90 patients with SAH will be randomised to one of three intervention arms: epoprostenol 1 ng/kg/min, epoprostenol 2 ng/kg/min or placebo in addition to standard treatment. Trial medication will start day 5 after SAH and continue to day 10. The primary outcome measure is changes in regional cerebral blood flow from baseline in the arterial territories of the anterior cerebral artery, medial cerebral artery and the posterior cerebral artery, measured by CT perfusion scan. The secondary outcomes will be vasospasm measured by CT angiography, ischaemic parameters measured by brain microdialysis, flow velocities in the medial cerebral artery, clinical parameters and outcome (Glasgow Outcome Scale) at 3 months.

TRIAL REGISTRATION

Clinicaltrials.gov NCT01447095.

Endovascular treatment of recurrent coiled aneurysms: assessment of complications and rebleeding during a decade in a single center

Recurrence is the main drawback of aneurysmal coiling. Additional coiling must sometimes be considered in patients with reopened aneurysms and expose the patient to the risk of a new procedure. Our purpose was to assess the procedural complications of additional endovascular treatments in patients with previously coiled but recurrent aneurysms treated by two neurointerventionalists during a decade in a single center. Between 1999 and 2009, 637 intracranial aneurysms were coiled and had a clinical and angiographic follow-up at our institution. Following the first embolization, 44 aneurysms were retreated with coils and 11 were retreated a second time. Retreatment was decided when a recurrence showed at angiographic follow-up. Early retreatments, performed in the first month after an incomplete or failed initial coiling, were excluded. We retrospectively analysed the procedural complications, rebleeding, clinical and angiographic outcomes of the retreatments. No death or bleeding occurred in these 55 additional procedures. We had three periprocedural thromboembolic complications and the procedural permanent morbidity was 1.8%. Clinical and angiographic follow-ups ranged from six months to nine years (mean: 37 months, median: 36 months). Thirty-seven of the 44 retreated aneurysms (84%) showed a stable occlusion at follow-up. Seven showed a recurrence but were not retreated due to the stability of the packing. No rebleeding was observed during the follow-up period. Our results show that endovascular treatment of recurrent aneurysms is associated with a low procedural risk.