Relevance of age and hypertension for blood pressure targets in comatose survivors of cardiac arrest: a BOX-trial sub-study

Eur Heart J Acute Cardiovasc Care. 2024 Sep 25;13(9):663-669. doi: 10.1093/ehjacc/zuae080.

Abstract

Aims: To assess whether the optimal mean arterial blood pressure (MAP) target after out-of-hospital cardiac arrest (OHCA) is influenced by age and a history of arterial hypertension.

Methods and results: A post hoc analysis of data from the Blood Pressure and Oxygenation Targets in Post Resuscitation Care trial. The trial included 789 comatose patients randomized to a MAP target of 63 or 77 mmHg. The primary outcome of this sub-study was 1-year all-cause mortality. Cox proportional hazards regression and restricted cubic splines were used to examine whether prevalent hypertension and age modified the effect of low vs. high MAP target on all-cause mortality. Of the 789 patients randomized, 393 were assigned to a high MAP target, and 396 to a low MAP target. Groups were well-balanced for mean age (high MAP target 63 ± 13 years vs. low 62 ± 14 years) and hypertension (45 vs. 47%, respectively). At 1 year, the primary outcome occurred in 143 patients (36%) with a high MAP target and 138 (35%) with a low MAP target. The risk of the primary outcome increased linearly with increasing age (P < 0.001). The effect of a high vs. low MAP target on the primary outcome was modified by age when tested continuously, potentially favouring a low MAP target in younger patients (P for interaction = 0.03). Prevalent hypertension did not modify the effect of a high vs. low MAP target on the primary outcome (P for interaction = 0.67).

Conclusion: Among patients resuscitated after OHCA, older patients and those with a history of hypertension did not benefit from a high MAP target.

Keywords: Age; Blood pressure; Out-of-hospital cardiac arrest; Outcome; Randomized controlled trial.

Publication types

  • Randomized Controlled Trial
  • Multicenter Study

MeSH terms

  • Age Factors
  • Aged
  • Blood Pressure / physiology
  • Cardiopulmonary Resuscitation / methods
  • Coma* / etiology
  • Coma* / physiopathology
  • Coma* / therapy
  • Female
  • Humans
  • Hypertension* / complications
  • Hypertension* / physiopathology
  • Male
  • Middle Aged
  • Out-of-Hospital Cardiac Arrest* / complications
  • Out-of-Hospital Cardiac Arrest* / mortality
  • Out-of-Hospital Cardiac Arrest* / therapy
  • Survival Rate / trends