Frequent CT surveillance of endovascular aneurysm repair may be unjustified

April 17, 2009

More than eight years of data from nearly 500 patients suggest that frequent monitoring with CT to look for complications after endovascular repair of abdominal aortic aneurysms is unnecessary and that it could be done instead with ultrasound.

More than eight years of data from nearly 500 patients suggest that frequent monitoring with CT to look for complications after endovascular repair of abdominal aortic aneurysms is unnecessary and that it could be done instead with ultrasound.

While open surgery remains the standard of care for patients with abdominal aortic aneurysm, studies establishing the comparative value of stent-graft repair keep piling up. Indications for endovascular aneurysm repair continue to be limited mainly to patients who are too frail for surgery, however, mostly due to lack of long-term data on EVAR's durability and complications. Early studies also showed that EVAR had a high rate of secondary interventions compared with surgery. Protocols thus recommended yearly monitoring with CT.

New evidence may dispel many myths about EVAR's durability and effectiveness as well as the need for prolonged CT scan surveillance, said senior investigator Dr. Tarun Sabharwal, an interventional radiologist at Guy's and St. Thomas' Hospital in London.

Sabharwal and colleagues prospectively enrolled 453 consecutive patients who underwent EVAR from April 2000 until January 2008. Researchers recorded the rate of secondary interventions and related complications and also analyzed if CT surveillance could predict the need for reintervention. The investigators found EVAR's reintervention rate was just as low as surgery's. They also found that most complications appear within three months after repair and that CT rarely spots any anomalies after that.

They released results of their study at the 2009 SIR meeting.

"This suggests that CT surveillance protocols are not justified," Sabharwal said. "If a three-month surveillance scan doesn't demonstrate any abnormalities, then patients could be followed with routine ultrasound scanning to monitor for complications."

Nearly nine in 10 patients in the study group chose to undergo endovascular repair, while 17 did so as urgent cases and 30 as emergency ruptures (3.6% and 6.6%, respectively). Thirty-three patients (7.2%) required a secondary intervention due mostly to type I and III endoleaks. Only six of them (1.3%), however, did so based on routine CT surveillance. EVAR's 30-day mortality rate was 3.3%. Surgery's 30-day mortality rate ranges in the clinical literature from as low as 2% to as high as 10.6%.

Long-term results prove that endovascular repair reduces the number of complications associated with surgery, including recovery time, Sabharwal said. Findings also contradict previous reports of high rates of secondary interventions and call for a revision of current CT surveillance protocols.

"Our data show that the interventional radiology treatment can be chosen with confidence. This is good news for patients, many of whom do not want major abdominal surgery," he said.