Neither individualized perioperative blood pressure (BP) management nor management stratified by risk of intraoperative hypotension improved outcomes in patients after noncardiac surgery, according to results of the IMPROVE-multi and PRETREAT trials, published recently in JAMA.

The IMPROVE-multi trial, conducted across 15 centers in Germany, focused on patients ≥45 years with at least one additional high-risk criterion who were undergoing elective major abdominal surgery with general anesthesia expected to last ≥90 minutes. Investigators Bernd Saugel, MD, et al., randomized 1,142 patients (median age, 66 years; 34% women) to either perioperative BP management with mean arterial pressure (MAP) targets based on perioperative mean nighttime MAP assessed through automated BP monitoring (n=571) or routine BP management with a MAP target of ≥65 mm Hg (n=571).

Results showed that 190 patients (34%) in the individualized treatment arm and 173 patients (31%) in the routine treatment arm experienced the primary outcome – a composite of acute kidney injury, acute myocardial injury, nonfatal cardiac arrest or death within the first seven postoperative days (relative risk, 1.10; p=0.31). Additionally, there were no significant differences in the 22 secondary outcomes, including infectious complications within seven days of surgery and a composite of need for kidney replacement therapy, myocardial infarction, nonfatal cardiac arrest or death within 90 days of surgery.

"The approach of individualizing MAP targets using preoperative mean nighttime MAP was based on pathophysiological rationale," the investigators noted, "but there is no evidence that nighttime MAP during normal sleep reflects the optimal MAP during surgery with general anesthesia," indicating future areas of study.

The PRETREAT trial also examined postsurgical outcomes based on intraoperative BP management – in this case stratified based on intraoperative hypotension risk. Conducted across two centers in the Netherlands, it focused on patients ≥18 years old undergoing elective noncardiac surgery. The primary outcome was functional disability at six months post surgery as assessed by the 12-item World Health Organization Assessment Schedule (WHODAS) 2.0, where a higher score indicates greater disability across cognition, mobility, self-care, interpersonal relationships, life activities and participation.

Investigators Matthijs Kant, MD, et al., randomized 3,247 patients (median age, 59 years; 54% women) to either standard BP management at the anesthesiologist's discretion (n=1,629, median baseline WHODAS 2.0, 14.6) or proactive management based on MAP goals stratified by hypotension risk (n=1,618; median baseline WHODAS 2.0, 12.5), falling into low (≥70 mm Hg), intermediate (≥80 mm Hg) or high (≥90 mm Hg) risk categories.

The trial, which initially planned for 5,000 patients, was stopped early for futility.

Results at six months showed that patients in the proactive treatment arm had a mean WHODAS 2.0 score of 17.7, while patients in the routine treatment arm had a mean WHODAS 2.0 score of 18.2, with the posterior probability of benefit of the intervention at 0.1%. There were no significant differences in any of the 23 secondary outcomes, including quality of life, postoperative complications and mortality within six months.

"The intervention in the current study used risk-stratified [BP] targets based on a preoperative intraoperative hypotension prediction model," the investigators write. "Although this approach reflects real-life decision-making and reduces overtreatment, it may have lacked sufficient individualization. Within each risk group, there may have been heterogeneous treatment effects, with some patients benefiting and others not, resulting in a net neutral effect."

In an accompanying editorial comment on both trials, Matthieu Legrand, PhD; François Lamontagne, MD; and Romain Pirracchio, MD, PhD, called the two "strikingly similar," despite different patient populations and surgery types, in that both "provide compelling new evidence that, even when individualized, aiming for higher MAP targets primarily through the use of vasoactive medications does not improve important patient outcomes."

"The long-standing assumption that 'higher is better' in patients undergoing high-risk surgery deserves reexamination, and future efforts should focus on the true drivers of perioperative risk rather than higher [BP] targets," add Legrand and colleagues.