Elevated Pulse Pressure in Anesthetized Subjects Before Cardiopulmonary Bypass Is Associated Strongly With Postoperative Acute Kidney Injury Stage

Association of Preoperative Pulse Pressure and Oxygen Delivery Index During Cardiopulmonary Bypass With Postoperative Acute Kidney Injury

OBJECTIVE

To investigate if oxygen delivery index during cardiopulmonary bypass (DO₂I) was more strongly associated with acute kidney injury (AKI), the higher the patient's preoperative pulse pressure (PP).

DESIGN

Retrospective cohort of 1064 patients undergoing cardiac surgery.

SETTING

Single academic healthcare center.

PARTICIPANTS

Adult patients undergoing coronary artery bypass grafting, valve, aortic, or combined surgery requiring cardiopulmonary bypass.

INTERVENTIONS

Hemoglobin, arterial oxygen saturation, and pump flow recorded no fewer than every 30 min were extracted from the patients' perfusion records, and DO₂I was calculated. The AKI was assessed from the pre- and postoperative creatinine and urine output values using the Acute Kidney Injury Network criteria. The sample was stratified in 5 categories of progressively higher PP. The patient characteristics and intraoperative variables were evaluated in univariate analysis for a relationship with AKI. The significant risk factors from the univariate analysis then were evaluated in a multivariate analysis and assessed for logistic fit with respect to AKI.

PRIMARY OUTCOME

The AKI assessed as a binary outcome.

MEASUREMENTS AND MAIN RESULTS

Age, body surface area, DO₂I, history of heart failure, and baseline creatinine were associated significantly with AKI, as was an interaction term between the PP category and DO₂I (p = 0.0067). The higher the PP category, the stronger the observed association between DO₂I and AKI, and the higher the variability in the predicted risk of AKI dependent on DO₂I.

CONCLUSIONS

A lower DO₂I during cardiopulmonary bypass appeared more strongly associated with a higher likelihood of developing AKI, the higher the patient's preoperative pulse pressure.

Renal Impairment After Cardiac Surgery: Risk Factors, Outcome and Cost Effectiveness

Introduction Acute kidney injury (AKI) is considered one of the serious complications in the medical field. It has a large impact on patients' life medically, socially and economically. It also has a financial burden on governments and hospitals regardless of which part of the world is considered. On the other hand, AKI is a common complication of cardiac surgery, which alone has a tremendous burden and implications on patients and governments. In this study, we will discuss the various risk factors, outcomes and financial burden of renal impairment associated with cardiac surgery. Methods This is a retrospective case-control study, which included 144 adult patients who underwent open cardiac surgical procedures at King Fahad University Hospital in the Eastern Province of Saudi Arabia over a period of five years from January 2015 till the end of December 2019. We included all types of cardiac surgeries performed such as coronary artery bypass grafting (CABG), valve surgery and aortic dissection repair and excluded patients with end-stage renal disease (ESRD) requiring dialysis preoperatively and pediatric patients. Two control groups were defined, those who developed renal impairment (group A) and those who did not develop it (group B). Results The mean age of the patients was 58.59 ± 12.6 years (range: 42 to 77 years). Mean serum creatinine level in the postoperative period was 1.95 ± 1.5 mg/dL in group A compared to group B of 1.0 ± 0.32 mg/dL (P-value<0.01). Mean serum blood urea nitrogen (BUN) in group A was 26.45 ± 19.9 mg/dL compared to group B of 16.79 ± 16.2 mg/dL in group B (P-value < 0.01). Diabetic were more likely to develop renal impairment than non-diabetic (P-value = 0.049, OR 2.73; 95% CI: 0.97-7.66). Obese patients were two times more likely to develop renal impairment than non-obese (P-value = 0.056, OR 2.6; 95% CI: 0.94-7.1). The average cost for each patient with renal impairment who required dialysis was 110,000 Saudi Riyal (~ 29,000 $) compared to other patients. Conclusion Serum creatinine, BUN, diabetes and obesity are strong indicators in developing AKI in cardiac surgery. In addition, the financial burden was almost doubled in patients developing AKI.

End-of-Procedure Volume Responsiveness Defined by the Passive Leg Raise Test Is Not Associated With Acute Kidney Injury After Cardiopulmonary Bypass

OBJECTIVES

Renal hypoperfusion is a common mechanism of cardiac surgery-related acute kidney injury (CS-AKI). However, the optimal amount of volume resuscitation to correct systemic hypoperfusion and prevent the postoperative development of CS-AKI has been a subject of debate. The goal of this study was to assess the association of volume responsiveness determined by stroke volume variation using the passive leg raise test (PLRT) at chest closure, with the development of CS-AKI according to the Kidney Disease Improving Global Outcomes criteria.

DESIGN

Single-center, prospective observational study.

SETTING

Tertiary hospital.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

A total of 131 patients were studied from January 2015 until May 2017. All patients underwent cardiac surgery that required cardiopulmonary bypass. Volume responsiveness was assessed at chest closure using the PRLT. Stroke volume variation from the sitting to the recumbent positions was measured by transesophageal echocardiography. Fluid responsiveness was defined as an increase of >12% of stroke volume from sitting to recumbent positions. A total of 82 (68.3%) patients were fluid-responsive versus 38 (31.6%) who were fluid-unresponsive. CS-AKI occurred in 30% of patients. There was no difference in CS-AKI between fluid-responsive and fluid-nonresponsive groups. However, CS-AKI was associated independently with an increases in body mass index and preoperative diastolic blood pressure. CS-AKI also was associated with prolonged intensive care unit length of stay.

CONCLUSION

End-of-procedure volume responsiveness is not associated with a high risk for postoperative CS-AKI.

Preoperative Pulse Pressure and Adverse Postoperative Outcomes: A Meta-Analysis

OBJECTIVE

To evaluate the association between preoperative pulse pressure (PP) and the incidences of renal, neurologic, cardiac, and mortality outcomes after surgery.

DESIGN

Systematic review and meta-analysis of cohort studies.

SETTING

Hospitals.

PARTICIPANTS

Patients who underwent cardiac or noncardiac surgeries.

INTERVENTION

The preoperative PP was measured.

MEASUREMENT AND MAIN RESULTS

Relevant cohort studies were obtained by systematic search of PubMed and Embase databases. A randomized effect model was used to pool the results. The multivariate adjusted risk ratio (RR) and its 95% confidence intervals (CI) were calculated to reflect the association between preoperative PP and adverse postoperative outcomes. Twelve cohort studies that included 40,143 patients who had undergone cardiac, vascular, or noncardiac surgery were included in the meta-analysis. The results showed that above a threshold of 40 mmHg, an increase in preoperative PP of 10 mmHg was independently associated with increased risk for renal events (adjusted RR: 1.13, 95% CI 1.08-1.19, p < 0.001; I² = 0%), neurologic events (adjusted RR: 1.75, 95% CI 1.01-3.02, p = 0.04; I² = 70%), cardiac events (adjusted RR: 1.19, 95% CI 1.03-1.37, p = 0.01; I² = 0%), major cardiovascular adverse events (adjusted RR: 1.62, 95% CI 1.10-2.41, p = 0.02; I² = 0%), and overall mortality (adjusted RR: 1.13, 95% CI 1.07-1.20, p < 0.001; I² = 0%) after surgery.

CONCLUSIONS

Patients with higher-than-normal preoperative PP are at increased risk for adverse postoperative outcomes.