Effect of blood pressure threshold on adverse outcomes in patients with acute spinal cord injury: a systematic review and meta-analysis.

BACKGROUND

Inadequate spinal perfusion in acute spinal cord injury (SCI) can exacerbate secondary injury. While current guidelines recommend maintaining mean arterial pressure (MAP) ≥ 75-80mmHg post-injury, no quantitative analysis on effects of blood pressure on neurological outcomes exists. We aim to address this gap and evaluate the impact of blood pressure thresholds on adverse outcomes in acute traumatic and non-traumatic SCI to inform current guidelines.

METHODS

The project adhered to PRISMA and MOOSE guidelines and was registered in PROSPERO (CRD42024550044). We searched seven databases: MEDLINE, Embase, Cochrane Central, Cochrane Reviews, CINAHL, Scopus, and Web of Science. We included studies involving patients ≥ 16yrs with acute SCI, randomized control trials, prospective cohorts, and retrospective (case-control, cohort) studies. Excluded were chronic SCI and studies mentioning induced hypotension. The main outcome was the relationship between blood pressure thresholds and adverse functional outcome at up to one-year post-injury. Outcomes (unadjusted odds ratios (uOR) and adjusted odds ratios (aOR)) were calculated using a random-effect model with 95% confidence intervals (CI). Quality was assessed using the Newcastle-Ottawa Scale and Cochrane Risk of Bias Tool.

RESULTS

Of 16,366 identified articles, 38 (n = 7,167, 73% male) were included in the qualitative and 14 (n = 2,553, 76% male) in the quantitative analysis. Pooled analysis found an increase in adverse functional outcomes in patients with below threshold blood pressures (uOR, 3.28; 95% CI, 2.39-4.50; aOR, 1.04; 95% CI, 1.03-1.05). Subgroup analyses consistently showed that lower blood pressure thresholds were associated with worse outcomes across all subgroups. Risk of bias was low to moderate in most studies. Heterogeneity was moderate to high (I: 69.88%).

CONCLUSION

Lower blood pressure thresholds were consistently associated with worse functional outcomes in patients with acute SCI. While these findings support the rationale for MAP augmentation, they should be interpreted cautiously due to the observational nature of the data and high heterogeneity. High-quality prospective studies are needed to determine optimal blood pressure targets.