Blood Pressure Targets Show No Benefit in Comatose Survivors of Cardiac Arrest

Comparing two clinically relevant mean arterial blood-pressure targets revealed no significant differences in study outcomes in comatose survivors of out-of-hospital cardiac arrest, according to new findings.

Study data suggest a blood pressure target of 77 mm Hg or 63 mm Hg in this patient population did not lead to significant differences in the percentage of patients who died or had severe disability or coma.

“The results appeared to be consistent across most of the prespecified subgroups,” wrote study author Jesper Kjaergaard, Department of Cardiology, Copenhagen University Hospital.

The research waa presented at the European Society of Cardiology Congress 2022 in Barcelona, Spain.

Kjaergaard and colleagues developed a method to perform double-blind prospective trials of blood pressure targets in patients in intensive care, utilizing the method in the Blood Pressure and Oxygenation Targets in Post Resuscitation Care (BOX) trial.

In the randomized trial with a 2-by-2 factorial design, investigators tested whether a higher (77 mm Hg) or lower (63 mm Hg) target mean arterial blood pressure was superior in preventing death or severe anoxic brain injury in comatose survivors of out-of-hospital cardiac arrest.

They assigned comatose patients (≥18 years old) to be treated to meet one of two of these blood pressure targets and to undergo restrictive oxygenation or liberal oxygenation while the patient remained in the intensive care unit (ICU). Randomization took place from March 2017 - December 2021 at 2 tertiary cardiac arrest centers in Denmark.

The primary outcome was the composite of death from any cause or discharge from the hospital with a Cerebral Performance Category (CPC) of 3 or 4 within 90 days after randomization. Investigators noted higher categories indicated more severe disability on the 5-point scale, with a category of 3 or 4 indicating severe disability or coma.

Secondary outcomes consisted of death from any cause within 90 days, time to renal-replacement therapy, neuron-specific enolase levels at 48 hours after randomization, the Montreal Cognitive Assessment score at 3 months, the modified Rankin score at 3 months, and the CPC at 3 months.

The analysis included a total of 789 patients (393 in the high-target group and 396 in the low-target group), with well-balanced baseline characteristics.

At the 90-day mark, a primary outcome event had occurred in 133 patients (34%) in the high-target group and 127 patients (32%) in the low-target group (hazard ratio [HR], 1.08; 95% CI, 0.84 to 1.37; P = .56). Further, 24 patients (3%) were discharged from the hospital with a CPC of 3 or 4

Moreover, a total of 122 of 393 patients (31%) in the high-target group and 114 of 393 patients (29%) in the low-target group died within 90 days (HR, 1.13; 95% CI, 0.88 - 1.46).

Data show the median CPC was 1 in both the high-target group and the low target group, while the corresponding mean-modified Rankin scale scores were 1 and 1 and the corresponding median Montreal Cognitive Assessment scores were 27 and 26.

There were no significant differences observed in the percentages of patients with adverse events, including infection, arrhythmia, bleeding, and seizures.

The study. “Blood-Pressure Targets in Comatose Survivors of Cardiac Arrest,” was published in the New England Journal of Medicine.