Is Preoperative Endothelial Dysfunction a Potentially Modifiable Risk Factor for Renal Injury Associated With Noncardiac Surgery?

OBJECTIVES: To determine whether preoperative endothelial dysfunction provides risk stratification for perioperative renal injury in patients undergoing noncardiac surgery. The relationship between perioperative renal injury and myocardial injury after noncardiac surgery (MINS) was explored secondarily. DESIGN: An observational study. SETTING: Two academic medical centers. PARTICIPANTS: A total of 218 patients scheduled to undergo intermediate or high-risk noncardiac surgery. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Endothelial dysfunction was identified preoperatively by a Reactive Hyperemia-Peripheral Arterial Tonometry (RH-PAT) index. Renal injury was defined by peak delta serum creatinine (ΔSCr) or creatinine-based kidney disease: Improving global outcomes acute kidney injury (AKI) criteria within 7 days postoperatively. MINS was defined by peak troponin ≥0.04 µg/L within 3 days postoperatively. AKI occurred in 22 patients (10.1%). Median RH-PAT index within the study cohort was 1.64 (range 1.03-4.96) and did not differ between patients with or without AKI. When adjusted for covariates, there was no association between RH-PAT index and either AKI or peak ΔSCr. MINS occurred in 32 patients (14.7%) and was associated independently with the outcome of AKI (odds ratio [OR], 3.7; 95% confidence interval [CI], 1.2-10.8; p = 0.02) and peak ΔSCr (ß-regression coefficient 23; 95% CI, 9-37; p = 0.002). Co-occurrence of AKI and MINS portended a marked increase in 30-day mortality (OR, 43; 95% CI, 6-305; p = 0.001) and delayed time to discharge (hazard ratio, 0.27; 95% CI, 0.13-0.54; p = 0.001). CONCLUSIONS: For patients undergoing noncardiac surgery, preoperative endothelial function assessed by noninvasive peripheral arterial tonometry was not associated with perioperative AKI. Perioperative renal injury was associated strongly with MINS, and this may represent a mechanism by which AKI increases adverse outcomes.

Systemic inflammation in the elderly.

Inflammation is an adaptive response to surgery. When the pro-inflammatory responses are unregulated and become over reactive, systemic inflammatory response syndrome may occur. Postoperative systemic inflammation is more common than is generally acknowledged and is observed in about 10-15% of elderly patients undergoing major surgery. Although the vast majority of systemic inflammation is related to infections, other important predisposing risk factors, such as extent of trauma and haemorrhage, should not be overlooked. Increased awareness, modification of risk factors and early recognition are the key elements in the management of systemic inflammation. Prompt resuscitation aiming to correct hypotension, hypovolaemia and tissue hypoxia may improve outcome. Future large prospective observational studies are needed to define the incidence, risk factors and impact of systemic inflammatory syndrome in the elderly surgical patients. A better understanding of the molecular events during the systemic inflammatory response syndrome is required for future development of specific immunotherapy.