Intraoperative Hypotension Is Associated With Adverse Clinical Outcomes After Noncardiac Surgery.

BACKGROUND: Intraoperative hypotension (IOH) occurs frequently during surgery and may be associated with organ ischemia; however, few multicenter studies report data regarding its associations with adverse postoperative outcomes across varying hemodynamic thresholds. Additionally, no study has evaluated the association between IOH exposure and adverse outcomes among patients by various age groups. METHODS: A multicenter retrospective cohort study was conducted between 2008 and 2017 using intraoperative blood pressure data from the US electronic health records database to examine postoperative outcomes. IOH was assessed in 368,222 noncardiac surgical procedures using 5 methods: (a) absolute maximum decrease in mean arterial pressure (MAP) during surgery, (b) time under each absolute threshold, (c) total area under each threshold, (d) time-weighted average MAP under each threshold, and (e) cumulative time under the prespecified relative MAP thresholds. MAP thresholds were defined by absolute limits (≤75, ≤65, ≤55 mm Hg) and by relative limits (20% and 40% lower than baseline). The primary outcome was major adverse cardiac or cerebrovascular events; secondary outcomes were all-cause 30- and 90-day mortality, 30-day acute myocardial injury, and 30-day acute ischemic stroke. Residual confounding was minimized by controlling for observable patient and surgical factors. In addition, we stratified patients into age subgroups (18-40, 41-50, 51-60, 61-70, 71-80, >80) to investigate how the association between hypotension and the likelihood of major adverse cardiac or cerebrovascular events and acute kidney injury differs in these age subgroups. RESULTS: IOH was common with at least 1 reading of MAP ≤75 mm Hg occurring in 39.5% (145,743) of cases; ≤65 mm Hg in 19.3% (70,938) of cases, and ≤55 mm Hg in 7.5% (27,473) of cases. IOH was significantly associated with the primary outcome for all age groups. For an absolute maximum decrease, the estimated odds of a major adverse cardiac or cerebrovascular events in the 30-day postsurgery was increased by 12% (95% confidence interval [CI], 11-14) for ≤75 mm Hg; 17.0% (95% CI, 15-19) for ≤65 mm Hg; and by 26.0% (95% CI, 22-29) for ≤55 mm Hg. CONCLUSIONS: IOH during noncardiac surgery is common and associated with increased 30-day major adverse cardiac or cerebrovascular events. This observation is magnified with increasing hypotension severity. The potentially avoidable nature of the hazard, and the extent of the exposed population, makes hypotension in the operating room a serious public health issue that should not be ignored for any age group.

Postoperative Hypotension and Adverse Clinical Outcomes in Patients Without Intraoperative Hypotension, After Noncardiac Surgery.

BACKGROUND: Postoperative hypotension (POH) is associated with major adverse events. However, little is known about the association of blood pressure thresholds and outcomes in postoperative patients without intraoperative hypotension (IOH) on the general-care ward. We evaluated the association of POH with major adverse cardiac or cerebrovascular events (MACCE) in patients without IOH. METHODS: This retrospective analysis included 67,968 noncardiac patient-procedures (2008-2017) for patients discharged to the ward with postoperative mean arterial pressure (MAP) readings, managed for ≥48 hours postsurgery, with no evidence of IOH. The primary outcome was 30-day MACCE evaluated by postoperative MAP thresholds: ≤75, ≤65, and ≤55 mm Hg (POH defined as a single measurement below threshold). Secondary outcomes included all-cause mortality (30-/90-day), 30-day acute myocardial infarction, 30-day acute ischemic stroke, 30-day readmission, 7-day acute kidney injury, and 30-day readmission. Associations between POH and adverse events were also evaluated in a cohort (#2) of 16,034 patient-procedures with IOH (intraoperative MAP ≤65 mm Hg). RESULTS: In patients without IOH, exposure to POH was not associated with MACCE at any investigated MAP threshold (P < .016 was considered significant: ≤75 mm Hg, hazard ratio [HR] 1.18 [98.4% confidence interval {CI} 0.99-1.39], P = .023; ≤65 mm Hg, HR 1.18 [0.99-1.41], P = .028; ≤55 mm Hg, HR 1.23 [0.90-1.71], P = .121); however, associations were observed at all MAP thresholds for secondary outcomes of acute kidney injury and 30-day readmission, for 30-/90-day mortality for MAP ≤65 mm Hg, and 90-day mortality for MAP ≤55 mm Hg, compared to those without POH. No associations were detected between POH and secondary outcomes of acute ischemic stroke or acute myocardial infarction at any MAP threshold. No interaction between POH and IOH was found when we evaluated the association of POH on outcomes in the data set including all patients, regardless of IOH status (P values for interaction terms nonsignificant). When the interaction term was utilized, the association between POH without IOH and MACCE was significant for MAP ≤75 mm Hg (HR 1.20 [1.01-1.41]) and MAP ≤65 mm Hg (HR 1.21 [1.02-1.45]), but not MAP ≤55 mm Hg. Cohort #2 (POH with IOH) showed largely similar results for MACCE: not significant for MAP ≤75 and ≤65 mm Hg, but significant for MAP ≤55 mm Hg (HR 1.53 [1.05-2.22], P = .006). CONCLUSIONS: POH in patients without IOH was not associated with MACCE at any MAP investigated. No interaction was identified between POH and IOH. Large prospective randomized trials are necessary to develop better evidence and inform clinicians the value of postoperative blood pressure management.

Postoperative hypotension in patients discharged to the intensive care unit after non-cardiac surgery is associated with adverse clinical outcomes.

BACKGROUND: The postoperative period is critical for a patient's recovery, and postoperative hypotension, specifically, is associated with adverse clinical outcomes and significant harm to the patient. However, little is known about the association between postoperative hypotension in patients in the intensive care unit (ICU) after non-cardiac surgery, and morbidity and mortality, specifically among patients who did not experience intraoperative hypotension. The goal of this study was to assess the impact of postoperative hypotension at various absolute hemodynamic thresholds (≤ 75, ≤ 65 and ≤ 55 mmHg), in the absence of intraoperative hypotension (≤ 65 mmHg), on outcomes among patients in the ICU following non-cardiac surgery. METHODS: This multi-center retrospective cohort study included specific patient procedures from Optum® healthcare database for patients without intraoperative hypotension (MAP ≤ 65 mmHg) discharged to the ICU for ≥ 48 h after non-cardiac surgery with valid mean arterial pressure (MAP) readings. A total of 3185 procedures were included in the final cohort, and the association between postoperative hypotension and the primary outcome, 30-day major adverse cardiac or cerebrovascular events, was assessed. Secondary outcomes examined included all-cause 30- and 90-day mortality, 30-day acute myocardial infarction, 30-day acute ischemic stroke, 7-day acute kidney injury stage II/III and 7-day continuous renal replacement therapy/dialysis. RESULTS: Postoperative hypotension in the ICU was associated with an increased risk of 30-day major adverse cardiac or cerebrovascular events at MAP ≤ 65 mmHg (hazard ratio [HR] 1.52; 98.4% confidence interval [CI] 1.17-1.96) and ≤ 55 mmHg (HR 2.02, 98.4% CI 1.50-2.72). Mean arterial pressures of ≤ 65 mmHg and ≤ 55 mmHg were also associated with higher 30-day mortality (MAP ≤ 65 mmHg, [HR 1.56, 98.4% CI 1.22-2.00]; MAP ≤ 55 mmHg, [HR 1.97, 98.4% CI 1.48-2.60]) and 90-day mortality (MAP ≤ 65 mmHg, [HR 1.49, 98.4% CI 1.20-1.87]; MAP ≤ 55 mmHg, [HR 1.78, 98.4% CI 1.38-2.31]). Furthermore, we found an association between postoperative hypotension with MAP ≤ 55 mmHg and acute kidney injury stage II/III (HR 1.68, 98.4% CI 1.02-2.77). No associations were seen between postoperative hypotension and 30-day readmissions, 30-day acute myocardial infarction, 30-day acute ischemic stroke and 7-day continuous renal replacement therapy/dialysis for any MAP threshold. CONCLUSIONS: Postoperative hypotension in critical care patients with MAP ≤ 65 mmHg is associated with adverse events even without experiencing intraoperative hypotension.

Association of perioperative hypotension with subsequent greater healthcare resource utilization.

STUDY OBJECTIVE: Determine if perioperative hypotension, a modifiable risk factor, is associated with increased postoperative healthcare resource utilization (HRU). DESIGN: Retrospective cohort study. SETTING: Multicenter using the Optum® electronic health record database. PATIENTS: Patients discharged to the ward after non-cardiac, non-obstetric surgeries between January 1, 2008 and December 31, 2017 with six months of data, before and after the surgical visit. INTERVENTIONS/EXPOSURE: Perioperative hypotension, a binary variable (presence/absence) at an absolute MAP of ≤65-mmHg, measured during surgery and within 48-h after, to dichotomize patients with greater versus lesser hypotensive exposures. MEASUREMENTS: Short-term HRU defined by postoperative length-of-stay (LOS), discharge to a care facility, and 30-day readmission following surgery discharge. Mid-term HRU (within 6 months post-discharge) quantified via number of outpatient and emergency department (ED) visits, and readmission LOS. MAIN RESULTS: 42,800 distinct patients met study criteria and 37.5% experienced perioperative hypotension. After adjusting for study covariates including patient demographics and comorbidities, patients with perioperative hypotension had: longer LOS (4.01 vs. 3.83 days; LOS ratio, 1.05; 95% CI, 1.04-1.06), higher odds of discharge to a care facility (OR, 1.18; 95% CI, 1.12-1.24; observed rate 22.1% vs. 18.1%) and of 30-day readmission (OR, 1.22; 95% CI, 1.11-1.33; observed rate 6.2% vs. 5.0%) as compared to the non-hypotensive population (all outcomes, p < 0.001). During 6-month follow-up, patients with perioperative hypotension showed significantly greater HRU regarding number of ED visits (0.34 vs. 0.31 visits; visit ratio, 1.10; 95% CI, 1.05-1.15) and readmission LOS (1.06 vs. 0.92 days; LOS ratio, 1.15; 95% CI, 1.07-1.24) but not outpatient visits (10.47 vs. 10.82; visit ratio, 0.97; 95% CI, 0.95-0.99) compared to those without hypotension. There was no difference in HRU during the 6-month period before qualifying surgery. CONCLUSIONS: We report a significant association of perioperative hypotension with an increase in HRU, including additional LOS and readmissions, both important contributors to overall medical costs.

Short and Mid-Term Economic Impact of Pulmonary Artery Catheter Use in Adult Cardiac Surgery: A Hospital and Integrated Health System Perspective.

OBJECTIVE: A monitoring pulmonary artery catheter (PAC) is utilized in approximately 34% of the US cardiac surgical procedures. Increased use of PAC has been reported to have an association with complication rates: significant decreases in new-onset heart failure (HF) and respiratory failure (RF), but increases in bacteremia and urinary tract infections. We assessed the impact of increasing PAC adoption on hospital costs among cardiac surgery patients for US-based healthcare systems. METHODS: An Excel-based economic model calculated annualized savings for a US hospital with various cardiac surgical volumes and PAC adoption rates. A second model, for an integrated payer-provider health system, analyzed outcomes/costs resulting from the cardiac surgical admission and for the treatment of persistent HF and RF complications in the year following surgery. Model inputs were extracted from published literature, and one-way and probabilistic sensitivity analyses were performed. RESULTS: For an acute care hospital with 500 procedures/year and 34% PAC adoption, annualized savings equalled $61,806 vs no PAC utilization. An increase in PAC adoption rate led to increased savings of $134,751 for 75% and $170,685 for 95% adoption. Savings ranged from $12,361 to $185,418 at volumes of 100 and 1500 procedures/year, respectively. For an integrated payer-provider health system with the base-case scenario of 3845 procedures/year and 34% PAC adoption, estimated savings were $596,637 for the combined surgical index admission and treatment for related complications over the following year. CONCLUSION: PAC utilization in adult cardiac surgery patients results in reduced costs for both acute care hospitals and payer-provider integrated health systems.

Abnormal shock index exposure and clinical outcomes among critically ill patients: A retrospective cohort analysis.

PURPOSE: To assess the predictive value of a single abnormal shock index reading (SI ≥0.9; heart rate/systolic blood pressure [SBP]) for mortality, and association between cumulative abnormal SI exposure and mortality/morbidity. MATERIALS AND METHODS: Cohort comprised of adult patients with an intensive care unit (ICU) stay ≥24-h (years 2010-2018). SI ≥0.9 exposure was evaluated via cumulative minutes or time-weighted average; SBP ≤100-mmHg was analyzed. Outcomes were in-hospital mortality, acute kidney injury (AKI), and myocardial injury. RESULTS: 18,197 patients from 82 hospitals were analyzed. Any single SI ≥0.9 within the ICU predicted mortality with 90.8% sensitivity and 36.8% specificity. Every 0.1-unit increase in maximum-SI during the first 24-h increased the odds of mortality by 4.8% [95%CI; 2.6-7.0%; p < .001]. Every 4-h exposure to SI ≥0.9 increased the odds of death by 5.8% [95%CI; 4.6-7.0%; p < .001], AKI by 4.3% [95%CI; 3.7-4.9%; p < .001] and myocardial injury by 2.1% [95%CI; 1.2-3.1%; p < .001]. ≥2-h exposure to SBP ≤100-mmHg was significantly associated with mortality. CONCLUSIONS: A single SI reading ≥0.9 is a poor predictor of mortality; cumulative SI exposure is associated with greater risk of mortality/morbidity. The associations with in-hospital mortality were comparable for SI ≥0.9 or SBP ≤100-mmHg exposure. Dynamic interactions between hemodynamic variables need further evaluation among critically ill patients.

Hospital costs associated with intraoperative hypotension among non-cardiac surgical patients in the US: a simulation model.

Objective: Recent studies indicate intraoperative hypotension, common in non-cardiac surgical patients, is associated with myocardial injury, acute kidney injury, and mortality. This study extends on these findings by quantifying the association between intraoperative hypotension and hospital expenditures in the US. Methods: Monte Carlo simulations (10,000 trial per simulation) based on current epidemiological and cost outcomes literature were developed for both acute kidney injury (AKI) and myocardial injury in non-cardiac surgery (MINS). For AKI, three models with different epidemiological assumptions (two models based on observational studies and one model based on a randomized control trial [RCT]) estimate the marginal probability of AKI conditional on intraoperative hypotension status. Similar models are also developed for MINS (except for the RCT case). Marginal probabilities of AKI and MINS sequelae (myocardial infarction, congestive heart failure, stroke, cardiac catheterization, and percutaneous coronary intervention) are multiplied by marginal cost estimates for each outcome to evaluate costs associated with intraoperative hypotension. Results: The unadjusted (adjusted) model found hypotension control lowers the absolute probability of AKI by 2.2% (0.7%). Multiplying these probabilities by the marginal cost of AKI, the unadjusted (adjusted) AKI model estimated a cost reduction of $272 [95% CI = $223-$321] ($86 [95% CI = $47-$127]) per patient. The AKI model based on relative risks from the RCT had a mean cost reduction estimate of $281 (95% CI = -$346-$750). The unadjusted (adjusted) MINS model yielded a cost reduction of $186 [95% CI = $73-$393] ($33 [95% CI = $10-$77]) per patient. Conclusions: The model results suggest improved intraoperative hypotension control in a hospital with an annual volume of 10,000 non-cardiac surgical patients is associated with mean cost reductions ranging from $1.2-$4.6 million per year. Since the magnitude of the RCT mean estimate is similar to the unadjusted observational model, the institutional costs are likely at the upper end of this range.

A Monte Carlo simulation estimating US hospital cost reductions associated with hypotension control in septic ICU patients.

OBJECTIVE: This economic analysis extends upon a recent epidemiological study to estimate the association between hypotension control and hospital costs for septic patients in US intensive care units (ICUs). METHODS: A Monte Carlo simulation decision analytic model was developed that accounted for the probability of complications-acute kidney injury and mortality-in septic ICU patients and the cost of each health outcome from the hospital perspective. Probabilities of complications were calculated based on observational data from 110 US hospitals for septic ICU patients (n = 8,782) with various levels of hypotension exposure as measured by mean arterial pressure (MAP, units: mmHg). Costs for acute kidney injury (AKI) and mortality were derived from published literature. Each simulation calculated mean hospital cost reduction and 95% confidence intervals based on 10,000 trials. RESULTS: In the base-case analysis hospital costs for a hypothetical "control" cohort (MAP of 65 mmHg) were $699 less per hospitalization (95% CI: $342-$1,116) relative to a "case" cohort (MAP of 60 mmHg). In the most extreme case considered (45 mmHg vs 65 mmHg), the associated cost reduction was $4,450 (95% CI: $2,020-$7,581). More than 99% of the simulated trials resulted in cost reductions. A conservative institution-level analysis for a hypothetical hospital (which assumes no benefit for increasing MAP above 65 mmHg) estimated a cost decline of $417 for a 5 mmHg increase in MAP per ICU septic patient. These results are applicable to the US only. CONCLUSIONS: Hypotension control (via MAP increases) for patients with sepsis in the ICU is associated with lower hospitalization cost.

Healthcare utilization and costs of cardiopulmonary complications following cardiac surgery in the United States.

PURPOSE: This study examined postoperative heart failure (HF) and respiratory failure (RF) complications and related healthcare utilization for one year following cardiac surgery. METHODS: This study identified adult patients undergoing isolated coronary artery bypass graft (CABG) and/or valve procedures from the Cerner Health Facts® database. It included patients experiencing postoperative HF or RF complications. We quantified healthcare utilization using the frequency of inpatient admissions, emergency department (ED) visits with or without hospital admission, and outpatient visits. We then determined direct hospital costs from the determined healthcare utilization. We analyzed trends over time for both HF and RF and evaluated the association between surgery type and HF complication. RESULTS: Of 10,298 patients with HF complications, 1,714 patients (16.6%) developed persistent HF; of the 10,385 RF patients, 175 (1.7%) developed persistent RF. Healthcare utilization for those with persistent complications over the one-year period following index hospital discharge comprised an average number of the following visit types: Inpatient (1.49 HF; 1.55 RF), Outpatient (2.02, 0.51), ED without hospital admission (0.33, 0.13), ED + Inpatient (0.08, 0.06). Per patient annual costs related to persistent complications of HF and RF were $20,857 and $30,745, respectively. There was a significant association between cardiac surgical type and the incidence of HF, with risk for isolated valve procedures (adjusted OR 2.60; 95% CI: 2.35-2.88) and CABG + valve procedures (adjusted OR 2.38; 95% CI: 2.17-2.61) exceeding risk for isolated CABG procedures. CONCLUSIONS: This study demonstrates that HF and RF complication rates post cardiac surgery are substantial, and complication-related healthcare utilization over the first year following surgery results in significant incremental costs. Given the need for both payers and providers to focus on healthcare cost reduction, this study fills an important gap in quantifying the mid-term economic impact of postoperative cardiac surgical complications.

The relationship between ICU hypotension and in-hospital mortality and morbidity in septic patients.

PURPOSE: Current guidelines recommend maintaining a mean arterial pressure (MAP) ≥ 65 mmHg in septic patients. However, the relationship between hypotension and major complications in septic patients remains unclear. We, therefore, evaluated associations of MAPs below various thresholds and in-hospital mortality, acute kidney injury (AKI), and myocardial injury. METHODS: We conducted a retrospective analysis using electronic health records from 110 US hospitals. We evaluated septic adults with intensive care unit (ICU) stays ≥ 24 h from 2010 to 2016. Patients were excluded with inadequate blood pressure recordings, poorly documented potential confounding factors, or renal or myocardial histories documented within 6 months of ICU admission. Hypotension exposure was defined by time-weighted average mean arterial pressure (TWA-MAP) and cumulative time below 55, 65, 75, and 85 mmHg thresholds. Multivariable logistic regressions determined the associations between hypotension exposure and in-hospital mortality, AKI, and myocardial injury. RESULTS: In total, 8,782 patients met study criteria. For every one unit increase in TWA-MAP < 65 mmHg, the odds of in-hospital mortality increased 11.4% (95% CI 7.8%, 15.1%, p < 0.001); the odds of AKI increased 7.0% (4.7, 9.5%, p < 0.001); and the odds of myocardial injury increased 4.5% (0.4, 8.7%, p = 0.03). For mortality and AKI, odds progressively increased as thresholds decreased from 85 to 55 mmHg. CONCLUSIONS: Risks for mortality, AKI, and myocardial injury were apparent at 85 mmHg, and for mortality and AKI risk progressively worsened at lower thresholds. Maintaining MAP well above 65 mmHg may be prudent in septic ICU patients.