Table 2.
Associations of intraoperative hypotension parameters with postoperative AKI in the SPARK-discovery cohort
| Outcome, Exposure, and Subgroup | Univariable Model | Multivariable Modela | ||
|---|---|---|---|---|
| sOR (95% CI) | P Value | Adjusted sOR (95% CI) | P Value | |
| Postoperative AKI | ||||
| Mean arterial pressure (per 10.3 mm Hg lower value) | 1.68 (1.61 to 1.76) | <0.001 | 1.18 (1.13 to 1.25) | <0.001 |
| In patients with hypotensionb | 2.00 (1.88 to 2.12) | <0.001 | 1.36 (1.26 to 1.46) | <0.001 |
| In patients without hypotensionb | 1.02 (0.89 to 1.18) | 0.80 | 1.00 (0.87 to 1.17) | 0.95 |
| Time with mean arterial pressure <65 mm Hg (per 37.6 min) | 1.64 (1.60 to 1.68) | <0.001 | 1.23 (1.19 to 1.27) | <0.001 |
| Area under curve <65 mm Hg (per 319.5 min × mm Hg) | 1.59 (1.65 to 1.65) | <0.001 | 1.19 (1.15 to 1.24) | <0.001 |
| Critical AKI | ||||
| Mean arterial pressure (per 10.3 mm Hg lower value) | 2.11 (1.92 to 2.32) | <0.001 | 1.43 (1.29 to 1.59) | <0.001 |
| In patients with hypotensionb | 2.36 (2.10 to 2.64) | <0.001 | 1.55 (1.35 to 1.77) | <0.001 |
| In patients without hypotensionb | 1.36 (0.91 to 2.16) | 0.16 | 1.30 (0.87 to 2.06) | 0.24 |
| Time with mean arterial pressure <65 mm Hg (per 37.6 min) | 1.49 (1.44 to 1.55) | <0.001 | 1.18 (1.12 to 1.23) | <0.001 |
| Area under curve <65 mm Hg (per 319.5 min × mm Hg) | 1.33 (1.28 to 1.37) | <0.001 | 1.12 (1.09 to 1.16) | <0.001 |
All BP parameters were included in the regression model as continuous variables, and standardized odds ratios per 1-SD higher are presented; the 1-SD values were 10.3 mm Hg for lowest mean arterial pressure values, 37.6 min for time under 65 mm Hg, and 319.5 min × mm Hg for area under curve under 65 mm Hg, respectively. The numbers of postoperative AKI events were 2230 (5%), the number of critical AKI was 443 (1%) in the SPARK-discovery cohort with 45,520 patients. SPARK, simple postoperative AKI risk; sOR, standardized odds ratio.
Multivariable model was adjusted for age, sex, eGFR, diabetes mellitus, surgery duration (continuous, hours), emergency operation, usage of renin-angiotensin-aldosterone system blockades, dipstick albuminuria, anemia (<13 g/dl for male, <12 g/dl for female), hypoalbuminemia (<3.5 g/dl), and hyponatremia (<135 mEq/L), without missing values.
Subgroups were divided according to presence of any mean arterial pressure <65 mm Hg during surgery. The subgroup with hypotension included 32,101 patients with 1827 (6%) AKI and 383 (1%) critical AKI events, respectively. The subgroup without hypotension included 13,419 patients with 403 (3%) AKI and 60 (0%) critical AKI events, respectively.