Background: Vasospasm, delayed infarcts and clinical deterioration due to delayed cerebral ischemia (CD-DCI) following digital subtraction angiography (DSA)-negative, spontaneous subarachnoid hemorrhage (SAH) are infrequently and inconsistently described in the literature.
Methods: To quantify and characterize rates of each, we reviewed our own series of 77 patients with DSA-negative, spontaneous SAH. Employing a PubMed search, we reviewed the literature and calculated directly adjusted overall rates of vasospasm, delayed infarcts and CD-DCI.
Results: In our own patient cohort, 26 % of patients suffered vasospasm, 4 % delayed infarcts and 4 % CD-DCI. Higher Hunt-Hess grade and diffuse SAH pattern were associated with higher rates of each. Incorporating results from 18 studies in the literature, the directly adjusted overall rate of vasospasm following DSA-negative SAH was 16.3 % (95 % CI 12.3-21.1). Adjusted overall rates of delayed infarcts and CD-DCI were 3.4 % (95 % CI 1.9-5.5) and 6.8 % (95 % CI 5.0-9.1), respectively. For the subgroup of patients with diffuse SAH, the rates of vasospasm and CD-DCI were 31.3 % (95 % CI 21.6-43.9) and 9.7 % (95 % CI 7.0-13.0), respectively, while in patients with perimesencephalic SAH, respective rates were 13.1 % (95 % CI 7.7-20.7) and 2.4 % (95 % CI 1.0-4.8). A mixed-effects meta-analysis revealed an odds ratio for CD-DCI in diffuse SAH compared to perimesencephalic SAH of 3.79 (p = 0.009).
Conclusion: Although they are seen less frequently in patients with DSA-negative spontaneous SAH, vasospasm, delayed infarcts and CD-DCI do occur and may require endovascular therapy. Risk factors include a diffuse hemorrhage pattern and higher Hunt-Hess grade.