Efficacy of nitroglycerin vs labetalol in hypertensive emergency among patients with a history of coronary artery disease

Abstract

BACKGROUND

Hypertensive emergencies, characterized by severe blood pressure elevation (> 180/120 mmHg) with end-organ damage, pose significant risks in patients with coronary artery disease (CAD), where rapid yet safe reduction is crucial to prevent ischemia and complications. Nitroglycerin and labetalol are common intravenous agents, but comparative data in CAD are limited.

AIM

To compare efficacy and safety of nitroglycerin vs labetalol in hypertensive emergencies among CAD patients, assessing blood pressure control, reductions, adverse events, outcomes, and utilization.

METHODS

Retrospective cohort of 563 CAD patients with hypertensive emergency (2018-2024) receiving IV nitroglycerin (n = 282) or labetalol (n = 281). Primary: Time to target blood pressure [systolic blood pressure (SBP) < 160 mmHg, diastolic blood pressure < 100 mmHg]. Secondary: Blood pressure reductions, major adverse cardiovascular event, safety, utilization. Analyzed via t-tests, χ², multivariable logistic regression adjusting for age, gender, myocardial infarction/heart failure history, diabetes, baseline SBP, chest pain.

RESULTS

Baseline characteristics were balanced. Labetalol achieved target blood pressure faster (25.14 ± 4.92 minutes vs 30.38 ± 5.16 minutes; P < 0.0001), but nitroglycerin yielded greater SBP (50.78 ± 9.45 mmHg vs 45.20 ± 10.46 mmHg; P < 0.0001) and diastolic blood pressure reductions (29.86 ± 8.63 mmHg vs 28.02 ± 7.74 mmHg; P = 0.0079). Nitroglycerin showed trends toward lower major adverse cardiovascular event [adjusted odds ratio (AOR): 0.72; 95% confidence interval (CI): 0.42-1.24], reduced bradycardia (AOR: 0.14; 95%CI: 0.05-0.38), shorter intensive care unit (2.99 ± 1.04 days vs 3.54 ± 1.02 days; P < 0.0001) and hospital stays (6.92 ± 1.93 days vs 7.99 ± 2.06 days; P < 0.0001), lower 30-day readmissions (AOR: 0.49; 95%CI: 0.27-0.88), and smaller biomarker increases (delta troponin: 0.10 ± 0.05 ng/mL vs 0.21 ± 0.10 ng/mL; P < 0.0001).

CONCLUSION

While labetalol offers faster blood pressure control, nitroglycerin is associated with greater reductions, fewer adverse events like bradycardia, and improved utilization (shorter stays, fewer readmissions) in CAD-associated hypertensive emergencies, supporting its use in ischemic contexts.

Keywords: Hypertensive emergency; Coronary artery disease; Nitroglycerin; Labetalol; Blood pressure control; Cardiovascular outcomes

Core Tip: This retrospective study uniquely compares intravenous nitroglycerin and labetalol for managing hypertensive emergencies in a large South Asian cohort of patients with established coronary artery disease. Although labetalol achieved target blood pressure more rapidly, nitroglycerin provided greater magnitude of blood pressure reduction, significantly lower rates of bradycardia, smaller rises in cardiac biomarkers, shorter intensive care unit and hospital stays, and reduced 30-day readmissions. These findings highlight nitroglycerin’s potential advantages in ischemic contexts and support its preferential use in high-risk coronary artery disease patients within resource-constrained settings.