Associations of Intraoperative Radial Arterial Systolic, Diastolic, Mean, and Pulse Pressures with Myocardial and Acute Kidney Injury after Noncardiac Surgery: A Retrospective Cohort Analysis

WHAT WE ALREADY KNOW ABOUT THIS TOPICArterial pressure is a complex signal that is characterized by three primary components — systolic, diastolic, and mean pressure, along with a derived component, pulse pressure (systolic minus diastolic pressure)Each blood pressure component reflects distinct hemodynamic variables, and therefore presumably differently influences perfusion of various organsPrevious work identifies associations between intraoperative systolic and mean hypotension with myocardial and kidney injury WHAT THIS ARTICLE TELLS US THAT IS NEWFor each blood pressure component, the authors report significant and clinically meaningful associations between the lowest pressure sustained for 5 min and myocardial and kidney injuryAbsolute population risk thresholds were similar for myocardial and kidney injury, being roughly 90 mmHg for systolic, 65 mmHg for mean, 50 mmHg for diastolic, and 35 mmHg for pulse pressuresThe odds for myocardial and kidney injury progressively increased with duration and severity of hypotension below each threshold, even after adjusting for potential baseline confounding factors BACKGROUND:Arterial pressure is a complex signal that can be characterized by systolic, mean, and diastolic components, along with pulse pressure (difference between systolic and diastolic pressures). The authors separately evaluated the strength of associations among intraoperative pressure components with myocardial and kidney injury after noncardiac surgery. METHODS:The authors included 23,140 noncardiac surgery patients at Cleveland Clinic who had blood pressure recorded at 1-min intervals from radial arterial catheters. The authors used univariable smoothing and multivariable logistic regression to estimate probabilities of each outcome as function of patients’ lowest pressure for a cumulative 5 min for each component, comparing discriminative ability using C-statistics. The authors further assessed the association between outcomes and both area and minutes under derived thresholds corresponding to the beginning of increased risk for the average patient. RESULTS:Out of 23,140 patients analyzed, myocardial injury occurred in 6.1% and acute kidney injury in 8.2%. Based on the lowest patient blood pressure experienced for greater than or equal to 5 min, estimated thresholds below which the odds of myocardial or kidney injury progressively increased (slope P < 0.001) were 90 mmHg for systolic, 65 mmHg for mean, 50 mmHg for diastolic, and 35 mmHg for