Acute kidney injury and chronic kidney disease, which are often found in patients undergoing major vascular surgeries, are associated with an increase in cardiovascular-specific mortality over time compared to patients without kidney disease, researchers report. Their study, titled “Cardiovascular-Specific Mortality and Kidney Disease in Patients Undergoing Vascular Surgery” and published in JAMA Surgery, recommends greater efforts in kidney care among vascular surgery patients.

Chronic kidney disease (CKD) has been shown to carry a higher risk for cardiovascular-specific mortality in the overall population, as well as a higher risk for adverse outcomes in patients undergoing vascular surgery. Acute kidney injury (AKI), a rapidly developing condition and common post-operative complication, is also considered a risk factor for long-term mortality after major vascular surgery. To overcome the limitations of previous studies, including small patient numbers and unspecified causes of mortality, researchers at the University of Florida investigated the association between cardiovascular-specific mortality and kidney disease in a large number of vascular surgery patients.

The study examined 3,646 patients who underwent vascular surgery at a tertiary care teaching hospital between January 2000 and November 2010. Around the time of surgery, AKI was present in 49% of patients and CKD in 13.6% of patients. The two main causes of the 1,577 deaths reported during the study and follow-up (completed in July 2014) were determined to be cardiovascular disease (53.6%) and cancer (11.0%). Adjusted cardiovascular mortality estimates at 10 years were reported at 17% for patients with no kidney disease, 31% in cases of AKI without CKD, 30% for CKD without AKI, and 41% in patients with both AKI and CKD. Moreover, researchers found that adjusted hazard ratios for cardiovascular mortality were significantly higher in patients with AKI, CKD, or with both conditions, when compared to other risk factors such as age, emergent surgery, and low hemoglobin levels.

“These findings reinforce the importance of preoperative CKD risk stratification through the application of consensus staging criteria for CKD using estimated glomerular filtration rate [a measure of kidney function] and albuminuria [the presence of excessive protein in the urine] for all patients undergoing major vascular surgery. Preoperative and postoperative risk stratification for AKI using clinical scores and urinary biomarkers similarly can help to direct the implementation of simple and inexpensive preventive strategies in the perioperative period that could prevent or mitigate further decline in kidney function,” the authors wrote, according to a press release. “The appropriate transition of patients undergoing surgery to follow-up in the outpatient setting with an emphasis on the prevention of kidney disease progression and mitigation of cardiovascular risk can be an important factor in improving the care of the patient undergoing vascular surgery who has AKI and/or CKD. Our findings present compelling evidence that such efforts are warranted and justifiable.”

Christian de Virgilio, MD, and Dennis Yong Kim, MD, from the Harbor-UCLA Medical Center, in California, further commented that these results “should prompt a call to action in terms of earlier diagnosis, treatment, and prevention of postoperative AKI. Novel biomarkers may furnish physicians with a narrow window to reverse or altogether avoid the development of AKI. Goal-directed intraoperative measures to maximize renal perfusion and the early use of renal replacement therapy may also have a role in prevention and treatment, respectively. Perhaps even more exciting is the application of preoperative therapeutic interventions such as remote ischemic preconditioning, which in a recent trial was associated with a significantly reduced rate of AKI following cardiac surgery. Regardless of the strategies used, it is readily apparent that it is time to start paying closer attention to postoperative AKI.”