Kidney damage: Women may be at higher risk after aneurysm repair

• About 200,000 people in the United States are affected by an abdominal aortic aneurysm (AAA) each year.
• Acute kidney injury is a known potential risk factor following surgical AAA repair.
• Researchers from Michigan Medicine have developed an algorithm to detect a person’s kidney damage risk before an endovascular AAA repair.
• Using their algorithm, scientists found women have a 1.4 times higher chance of developing acute kidney injury after an endovascular AAA repair.

Each year, about 200,000 people in the United States are affected by an abdominal aortic aneurysm (AAA).

An AAA occurs when the walls of the main artery that runs through the abdomen — the abdominal aorta — weaken, causing them to balloon into what is called an aneurysm.

Many times surgery — either endovascular or open surgery — is required to repair an AAA.

Previous research shows acute kidney injury is a potential risk factor with surgical AAA repair.

Researchers from Michigan Medicine recently designed an algorithm that can be used by doctors before performing an endovascular AAA repair to measure a person’s risk for developing kidney damage.

After applying their new algorithm to the data of more than 7,000 people, the researchers reported that women are 1.4 times more likely than men to develop acute kidney injury after receiving endovascular AAA repair.

This study was recently published in the journal Annals of Vascular Surgery.

What is acute kidney injury? 

Acute kidney injury occurs when the function of the kidneys declines and they are no longer able to remove waste products from the body.

This causes a build-up of waste in the body, which can lead to long-term kidney damage and chronic kidney disease.

Doctors use the Kidney Disease Improving Global Outcomes (KDIGO) to determine whether a person has acute kidney injury.

The KDIGO uses specific measures of the body waste product creatinine to make this judgement. Signs of kidney injury include:

• an increase in serum creatinine of more than or equal to 0.3 milligrams per deciliter within 48 hours.
• an increase in serum creatinine of more than or equal to 1.5 times the baseline within the previous seven days.
• urine volume of less than 0.5 milliliters/kilogram/hour over six hours.

Symptoms of acute kidney injury include:

• infrequent urination
• fatigue
• problems breathing and/or chest pain
• nausea
• swelling in the legs, ankles, and feet
• confusion

Acute kidney injury is most common in people who are in a hospital’s intensive care unit (ICU). Other risk factors for developing acute kidney injury include:

• age — older adults 65 and over
• undergoing a major surgery
• overuse of NSAIDs
• congestive heart failure
• history of kidney disease
• inflammation or damage to the kidney tubules
• enlarged prostate
• kidney stones
• certain cancers, including bladder, prostate, and cervical cancer
• severe dehydration
• severe burns
• serious infections

The link between AAA and kidney damage

The kidneys are located behind your abdomen. Each kidney receives blood through the renal arteries.

The renal arteries start at and branch off from the abdominal aorta. Because of that, anything affecting blood flow in the abdominal aorta may also impact the renal arteries feeding the kidneys.

Previous studies show acute kidney injury can occur following an AAA repair. It is also a major complication of ruptured AAA.

In this study, researchers focused on a particular type of kidney damage called contrast-associated acute kidney injury (CA-AKI).

This can develop after a person receives iodinated contrast material for CT imaging of their blood vessels before receiving AAA surgery.

Previous studies show acute kidney injury is a known potential side effect of diagnostic contrast drugs.

Developing an algorithm

Researchers first developed an algorithm for doctors to use to identify a person’s risk for developing acute kidney injury after an endovascular AAA repair.

After designing the algorithm, they tested it using data from more than 7,000 people in the Blue Cross Blue Shield of Michigan Cardiovascular Consortium database.

Upon analysis, the research team reported that women had a 1.4 times higher chance of developing acute kidney injury after receiving endovascular AAA repair.

“While we have seen a higher risk of acute kidney injury in female patients who have undergone coronary stenting or renal stenting, this is the first time we are seeing a higher risk after endovascular abdominal aortic aneurysm repair,” said Dr. Peter Henke, a vascular surgeon and director of the University of Michigan Health Frankel Cardiovascular Center and senior author of this study.

Scientists also found people with a reduced glomerular filtration rate had a 4.7 times higher chance of developing acute kidney injury after aneurysm repair. Additionally, those with larger aneurysms also had a higher risk for kidney damage.

Surprising results

After reviewing this study, Dr. Adi Iyer, a neurosurgeon and interventional neuroradiologist of Pacific Neuroscience Institute at Providence Saint John’s Health Center in California, told Medical News Today that he found the study surprising because doctors generally do not think of gender as being a factor related to patient outcome.

“When you look at the vasculature of patients — men and women — the blood vessels tend to look the same, so… differences in their kidney function and kidney failure after such procedures was surprising,” he added.

Iyer said there are a few ways these findings could help doctors in determining a person’s kidney damage risk prior to surgery.

“We would have to use our judgment in terms of how much contrast to use, consenting patients about the risk of kidney damage based on their sex, and just making sure patients have all the information of potential risks, and making sure that women know that they are slightly higher risk,” he said.

Medical News Today also spoke with Dr. Massimo M. Napolitano, the interim chair of the Department of Vascular Surgery at Hackensack University Medical Center in New Jersey, about this study.

“I was intrigued by the calculated higher risk among women for acute contrast-induced nephropathy,” he says. “Also, I found (it) interesting that the risk of CA-AKI increases within the group of patients with a larger aneurysm diameter.”

“It will increase awareness of this higher-risk population and trigger a more focused pre-operative optimization of the patient,” Napolitano added.

As for the next steps in this research, Napolitano said as the researchers pointed out in the study, a clinical trial is needed to confirm their findings.

“In particular, I would like to see data on the pre-operative hydration status of the patients and how that affects CA-AKI,” he said. “I also believe the amount of contrast used is an important factor in developing this complication.”

Source: Read Full Article