Elevated acute-phase plasma SPARC levels precede the development of angiographic vasospasm and delayed cerebral ischemia in severe aneurysmal subarachnoid hemorrhage.

OBJECTIVE: Delayed cerebral ischemia (DCI) remains a major determinant of poor outcome after aneurysmal subarachnoid hemorrhage (aSAH). Secreted protein acidic and rich in cysteine (SPARC) is a matricellular protein involved in neurovascular injury and blood-brain barrier dysfunction. However, the clinical significance of early plasma SPARC elevation in patients with severe aSAH remains unclear. METHODS: This retrospective study included 70 patients with severe aSAH (World Federation of Neurological Surgeons grades IV-V) enrolled in a prospective multicenter registry. Plasma SPARC levels were measured within days 1-3 after onset. The primary outcome was DCI, and the secondary outcome was angiographic vasospasm (AVSP). Plasma SPARC levels were log2-transformed and entered as a continuous variable in age-adjusted Firth penalized logistic regression analyses. RESULTS: Plasma SPARC levels did not significantly differ between patients with severe aSAH and control patients with unruptured intracranial aneurysms (61.8 [41.4-83.5] vs 54.5 [30.8-65.4] ng/mL, P = 0.081). Patients who subsequently developed DCI showed significantly higher plasma SPARC levels than those without DCI (121.2 [87.7-153.8] vs 56.1 [36.5-76.5] ng/mL, P < 0.001). Similarly, plasma SPARC levels were significantly elevated in patients with AVSP compared with those without AVSP (84.9 [58.4-125.4] vs 51.3 [32.8-73.9] ng/mL, P < 0.001). Age-adjusted Firth penalized logistic regression analyses demonstrated that higher plasma SPARC levels were significantly associated with DCI (adjusted odds ratio [aOR] per doubling, 6.835; 95% confidence interval [CI], 2.450-26.762; P < 0.001) and AVSP (aOR per doubling, 3.324; 95% CI, 1.665-7.729; P < 0.001). CONCLUSION: Early plasma SPARC elevation was significantly associated with both AVSP and DCI in patients with severe aSAH. Plasma SPARC may represent a potential biomarker of early neurovascular injury associated with subsequent ischemic complications.