2025 Southeastern Residency Conference

TITLE: Impact of Prior Beta-Blocker Use on Antihypertensive Escalation in Acute Ischemic Stroke 
 
AUTHORS: Shivani Patel PharmD, Kirbie Wells PharmD
 
OBJECTIVE: To identify the impact of home beta blocker use and its effect on labetalol for achieving blood pressure targets prior to administration of tissue plasminogen activator (tPA) in acute ischemic stroke patients at a rural community hospital. 
 
SELF ASSESSMENT QUESTION: What is the primary clinical concern when managing blood pressure in acute ischemic stroke (AIS) patients who are on beta-blocker therapy at home prior to alteplase (tPA) administration? 
A) Increased risk of hemorrhagic transformation due to excessive blood pressure lowering. 
B) Potential need for escalation to alternative antihypertensive agents after labetalol. 
C) Decreased efficacy of thrombolytic therapy due to beta-blocker-induced vasoconstriction. 
D) Higher likelihood of spontaneous blood pressure normalization without intervention. 
 
BACKGROUND: Stroke is a leading cause of mortality and disability in the U.S., with the highest burden in the Southeastern "stroke belt," where rural areas like Southwest Georgia face barriers to specialized care. In acute ischemic stroke (AIS), timely blood pressure control is crucial before alteplase (tPA) administration to reduce the risk of hemorrhagic transformation. The AHA/ASA recommends lowering systolic BP to <185 mmHg and diastolic BP to <110 mmHg using labetalol, hydralazine, or nicardipine, without specifying a preferred agent. However, prior beta-blocker use may reduce labetalol’s effectiveness due to beta-adrenergic receptor downregulation, necessitating escalation to other agents. This study evaluates whether outpatient beta-blocker use influences the need for additional antihypertensive therapy in AIS patients, potentially guiding personalized stroke management strategies.

METHODOLOGY: This study was a retrospective chart review which included adult patients diagnosed with acute ischemic stroke who had an initial SBP >185 mmHg or DBP >110 mmHg and received labetalol for blood pressure control prior to tPA administration treated at Phoebe Putney Memorial Hospital (PPMH) from January 2019 to December 2023. Patients were excluded if they were pregnant or transferred from another healthcare institution.  
 
RESULTS: A total of 199 patients were included: 65 with prior beta-blocker (BB) use and 134 without. The prior BB group was slightly younger (62 vs. 64.8 years) and heavier (96.6 vs. 83.2 kg). Stroke severity was similar between groups, with the prior BB group having a slightly higher percentage of severe strokes (15.4% vs. 12.7%). More patients with prior BB use required additional antihypertensives (37.5% vs. 19%). The interquartile range for door-to-needle time was 30.5–69 minutes, and for blood pressure control, 19.4–58.3 minutes. Severe hypotension occurred in 4.6% of the prior BB group and 9.7% of the no BB group. Intracerebral bleeding occurred in 6.2% of the prior BB group and 3.7% of the no BB group.
 
CONCLUSIONS: Patients on prior beta-blockers were more likely to require escalation to nicardipine or hydralazine for blood pressure control before Alteplase administration. These findings suggest that prior beta-blocker use may reduce the effectiveness of labetalol, necessitating a more individualized approach to antihypertensive management. Future studies should explore whether alternative first-line strategies could improve blood pressure control efficiency and minimize complications, particularly in resource-limited settings.