Arterial pulse pressure and postoperative morbidity in high-risk surgical patients

Systemic arterial pulse pressure (systolic minus diastolic pressure) ≤53 mm Hg in patients with cardiac failure is correlated with reduced stroke volume and is independently associated with accelerated morbidity and mortality. Given that deconditioned surgical and heart failure patients share similar cardiopulmonary physiology, we examined whether lower pulse pressure is associated with excess morbidity after major surgery.

This was a prospective observational cohort study of patients deemed by their preoperative assessors to be at higher risk of postoperative morbidity. Preoperative pulse pressure was calculated before cardiopulmonary exercise testing. The primary outcome was any morbidity (PostOperative Morbidity Survey) occurring within 5 days of surgery, stratified by pulse pressure threshold ≤53 mm Hg. The relationship between pulse pressure, postoperative morbidity, and oxygen pulse (a robust surrogate for left ventricular stroke volume) was examined using logistic regression analysis (accounting for age, sex, BMI, cardiometabolic co-morbidity, and operation type).

The primary outcome occurred in 578/660 (87.6%) patients, but postoperative morbidity was more common in 243/ 660 patients with preoperative pulse pressure ≤53 mm Hg{odds ratio (OR): 2.24 [95% confidence interval (CI): 1.29-3.38]; P<0.001). Pulse pressure ≤53 mm Hg [OR:1.23 (95% CI: 1.03-1.46); P=0.02] and type of surgery were independently associated with all-cause postoperative morbidity (multivariate analysis). Oxygen pulse <90% of population-predicted normal values was associated with pulse pressure ≤ 53 mm Hg [OR: 1.93 (95% CI: 1.32-2.84); P=0.007].

In deconditioned surgical patients, lower preoperative systemic arterial pulse pressure is associated with excess morbidity. These data are strikingly similar to meta-analyses identifying low pulse pressure as an independent risk factor for adverse outcomes in cardiac failure. Low preoperative pulse pressure is a readily available measure, indicating that detailed physiological assessment may be warranted.

ISRCT registry, ISRCTN88456378.