When does rebleeding occur in subarachnoid hemorrhage? Revisiting rebleeding cases with a focus on blood pressure

BACKGROUNDEarly brain injury attributable to initial or recurrent bleeding is the leading cause of poor outcomes in patients with subarachnoid hemorrhage (SAH). This study investigated rebleeding immediately after SAH ictus, focusing on its timing and associated blood pressure (BP). METHODSConsecutive patients with spontaneous SAH treated from January 1999 to June 2022 were reviewed. Rebleeding was defined as a sudden decline in consciousness to a coma, sudden pupillary dilation with elevated BP, or increased SAH on head computed tomography (CT). The rebleeding timing was examined during each management phase. Demographic, radiological, and initial evaluation data were assessed for rebleeding and outcomes. RESULTSAmong 940 patients (64% women, mean age 63.6 {+/-} 13.2, 73% with a World Federation of Neurological Societies grade [&ge;]4), rebleeding occurred in 221 cases (23.5%); 139 episodes in 121 patients (13.7%) before and 134 episodes in 112 patients after hospitalization (11.9%), and 19 patients (2.0%) in both. Rebleeding occurred more frequently in patients with worse neurological state, higher CT grades, and earlier arrivals. Systolic BP (SBP) was higher in patients with rebleeding (178 mmHg, IQR 140-204 mmHg) than in those without rebleeding (148 mmHg, IQR 100-180 mmHg) (P<0.001). Higher SBP was associated with increased rebleeding (OR 9.843; P<0.0001) and lower mortality (OR 0.0281; P=0.0084) but not with favorable outcomes (OR 1.686; P=0.22). When comparing the groups divided into 20 mmHg increments, the incidence of rebleeding, unfavorable outcomes, and mortality increased in the groups with SBP [&ge;]181 mmHg, SBP [&le;]100 mmHg and >160 mmHg, and SBP [&le;]100 mmHg, respectively. CONCLUSIONSRebleeding occurred in 23.5% of patients with SAH in the hyperacute phase, primarily before hospital arrival. Higher SBP was associated with rebleeding, and SBP of 101-160 mmHg was associated with favorable outcomes.