A Multidimensional Weight-Time-Frequency Score for Quantifying Intraoperative Hypotensive Burden During Off-Pump Coronary Artery Bypass Grafting
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Updated: Nov 2, 2026
Cardiac Loading using Passive Left Atrial Pressurization and Passive Afterload for Graft Assessment
Published on: August 2, 2024
Yuan Ma1, Jingcan Wang2, Jiange Han3
1The First Clinical Medical College, Lanzhou University, Lanzhou, Gansu Province, China.
Objectives:
To develop a multidimensional weight-time-frequency (WTF) score for quantifying cumulative intraoperative hypotensive burden during off-pump coronary artery bypass grafting (OPCABG) and to evaluate its association with postoperative outcomes.
Design:
Retrospective observational cohort study.
Setting:
A tertiary cardiac surgery center.
Participants:
Adults undergoing OPCABG with continuous intraoperative arterial pressure monitoring.
Interventions:
None.
Measurements And Main Results:
A qualifying hypotensive episode was defined as mean arterial pressure <65 mmHg sustained for at least 1 minute. The WTF score integrated hypotension depth, duration, and frequency, and outcome-specific cohorts were used for 30-day all-cause mortality, acute kidney injury (AKI), and new-onset atrial fibrillation (AF). Among 2,070 patients undergoing OPCABG, each 10-point increase in WTF was associated with higher adjusted odds of AF (adjusted odds ratio [OR], 1.155; 95% confidence interval [CI], 1.001-1.333), AKI (adjusted OR, 1.216; 95% CI, 1.001-1.478), and 30-day all-cause mortality (adjusted OR, 2.346; 95% CI, 1.332-4.130). Restricted cubic spline analyses showed generally increasing adjusted odds across the WTF range without significant nonlinearity. In test-set analyses, adding WTF yielded significant integrated discrimination improvement for AKI and significant IDI and continuous net reclassification improvement for 30-day mortality, whereas incremental gains for AF were minimal. Mortality findings should be interpreted cautiously because only 31 deaths occurred. WTF met the prespecified noninferiority criterion in 14 of 15 comparisons with conventional MAP-based metrics, including all comparisons for AF and AKI.
Conclusion:
The WTF score provides an interpretable cumulative measure of intraoperative hypotensive burden during OPCABG, shows adjusted associations with postoperative AF, AKI, and 30-day all-cause mortality and generally preserves discrimination comparable to conventional mean arterial pressure‒based metrics.
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