Background: The association between external ventricular drainage (EVD) and aneurysm rerupture is still a controversial issue. We performed a systematic review and meta-analysis of published series reporting data of EVD placement in aneurysmal subarachnoid hemorrhage (SAH) with the aim to evaluate the relationship between ventricular drainage and aneurysm rebleeding.
Method: PRISMA/MOOSE guidelines were followed. The Newcastle-Ottawa Scale was used to assess the quality of the studies. We conducted a comprehensive literature search of three databases (PubMed, Ovid MEDLINE, and Ovid EMBASE) on series reporting patients with EVD placement and aneurysmal SAH. The reported studies were analyzed with a primary aim to calculate the strength of the association (odds ratio) between rebleeding and EVD placement in patients with SAH.
Results: Our systematic review included 16 articles with a total of 6804 patients with SAH of which 595 (8.7%) had aneurysmal rebleeding. Ventricular drainage was inserted in 19% of patients. Rebleeding occurred in 18.8% (95% CI = 16.4-20.6%) of patients requiring EVD and in 6.4% (95% CI = 5.8-7.1%) of patients who did not require EVD (OR = 3.92, p < 0.0001). The mean time between EVD placement and rebleeding was 1 h (range, 0-8 h). The maximal aneurysm diameter of patients with rerupture was larger when compared with patients without rerupture (9.9 mm vs. 7.5 mm; p < 0.04). High Fisher grades (III-IV) were present in 75% of patients with rerupture and in 60% of patients without aneurysmal rerupture (p < 0.0001).
Conclusions: Our study conclusively defined an association between EVD and rebleeding. However, the effective role of EVD in aneurysm rebleeding is insufficiently investigated in the literature. Other significant factors of rebleeding are usually observed in patients requiring ventricular drainage. According to our findings, a causal relationship between EVD and aneurysm rebleeding could be a plausible hypothesis, at least in certain cases.
Keywords: Aneurysm rebleeding; Aneurysm rupture; External ventricular drainage; Intracranial aneurysms; Subarachnoid hemorrhage.