Associations of Intraoperative Radial Arterial Systolic, Diastolic, Mean, and Pulse Pressures with Myocardial and Acute Kidney Injury after Noncardiac Surgery: A Retrospective Cohort Analysis
Sanchit Ahuja, M.D.; Edward J. Mascha, Ph.D.; Dongsheng Yang, M.S.; Kamal Maheshwari, M.D, M.P.H.; Barak Cohen, M.D.; et alAshish K. Khanna, M.D., F.C.C.P., F.C.C.M.; Kurt Ruetzler, M.D.; Alparslan Turan, M.D.; Daniel I. Sessler, M.D.
 Author Notes
From the Departments of Outcomes Research, (S.A., E.J.M., D.Y., K.M., B.C., A.K.K., K.R., A.T., D.I.S.), Quantitative Health Sciences (E.J.M., D.Y.), and General Anesthesiology (K.M., K.R., A.T.), Cleveland Clinic, Cleveland, Ohio; the Department of Anesthesiology, Pain Management and Perioperative Medicine, Henry Ford Health System, Detroit, Michigan (S.A.); the Division of Anesthesia, Critical Care, and Pain Management, Tel-Aviv Medical Center, Tel Aviv University, Tel-Aviv, Israel (B.C.); and the Department of Anesthesiology, Section on Critical Care Medicine, Wake Forest School of Medicine, Wake Forest Center for Biomedical Informatics, and the Critical Injury, Illness and Recovery Research Center, Winston-Salem, North Carolina (A.K.K.).
Submitted for publication March 20, 2019. Accepted for publication October 14, 2019.
Part of this work has been presented at the American Society of Anesthesiologists Annual Meeting in San Francisco, California on October 13–14, 2018.
Correspondence: Address correspondence to Dr. Sessler: Michael Cudahy Professor and Chair, Department of Outcomes Research, Anesthesiology Institute, The Cleveland Clinic, 9500 Euclid Avenue — P77 Cleveland, Ohio 44195. DS@OR.org. Information on purchasing reprints may be found at www.anesthesiology.org or on the masthead page at the beginning of this issue. Anesthesiology’s articles are made freely accessible to all readers, for personal use only, 6 months from the cover date of the issue.
Anesthesiology Newly Published on November 25, 2019. doi:https://doi.org/10.1097/ALN.0000000000003048

Abstract
Editor’s Perspective:

What We Already Know about This Topic:

Arterial 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 organs

Previous work identifies associations between intraoperative systolic and mean hypotension with myocardial and kidney injury

What This Article Tells Us That Is New:

For each blood pressure component, the authors report significant and clinically meaningful associations between the lowest pressure sustained for 5 min and myocardial and kidney injury

Absolute 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 pressures

The 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 pulse pressure. Weak discriminative ability was noted between the pressure components, with univariable C-statistics ranging from 0.55 to 0.59. Area under the curve in the highest (deepest) quartile of exposure below the respective thresholds had significantly higher odds of myocardial injury after noncardiac surgery and acute kidney injury compared to no exposure for systolic, mean, and pulse pressure (all P < 0.001), but not diastolic, after adjusting for confounding.

Conclusions: Systolic, mean, and pulse pressure hypotension were comparable in their strength of association with myocardial and renal injury. In contrast, the relationship with diastolic pressure was poor. Baseline factors were much more strongly associated with myocardial and renal injury than intraoperative blood pressure, but pressure differs in being modifiable.