CHICAGO – Age greater than 76 years, plus preoperative creatinine greater than 2 mg/dL, blood pH less than 7.2, and systolic pressure at any point below 70 mm Hg collectively predicted 100% mortality with open or endovascular repair of ruptured abdominal aortic aneurysms, according to a new mortality risk score from Harborview Medical Center in Seattle.
Meeting all four criteria gives the maximum score of 4. Any one of the factors alone – a score of 1 – predicted 30% mortality with open repair and 9% with endovascular aneurysm repair (EVAR); a 2 predicted 80% mortality with open repair and 37% with EVAR; and a 3 predicted 82% mortality with open repair and 70% with EVAR.
Vascular surgeons at Harborview developed the system so they’d know whether to recommend transport or comfort care for ruptured abdominal aortic aneurysms (AAAs). The Level 1 trauma center serves more than a quarter of the U.S. landmass, and handles about 30-40 ruptured AAA’s annually. It’s not uncommon for patients to be flown in from Alaska.
Existing risk scores haven’t been validated for EVAR or rely on intraoperative variables, so they aren’t much help when counseling patients and referring physicians on what to do.
“Our ruptured AAA mortality risk score is based on four variables readily assessed preoperatively, allows accurate prediction of in-hospital mortality after repair of ruptured AAAs in the EVAR-first era, and does so better than any score thus published. It’s clinically relevant to the decision to transport and helps guide difficult discussions with patients and their families,” said investigator Dr. Ty Garland, chief vascular surgery resident at the University of Washington, Seattle.
When using the new risk score. “we don’t ever block transfer, but we have discussions with referring providers and in several cases with patients and their families over the telephone.” When the situation is hopeless, “we explain the data.” Twice in the past 6 months, patients have opted to spend their last hours at home with their families, Dr. Garland said at the Society for Vascular Surgery’s annual meeting.
To develop their system, the investigators culled through 37,000 variables from 303 ruptured AAA patients treated at Harborview from 2002-2013. Fifteen patients died in the emergency department, en route to surgery, or after choosing comfort care. Overall, 30-day mortality was 54% for open repair and 22% for EVAR.
On multivariate analysis, the team isolated the four preoperative variables most predictive of death. Preoperative creatinine greater than 2 mg/dL almost quadrupled the risk (odds ratio 3.7; P < .001); systolic blood pressure less than 70 mm Hg nearly tripled it (OR 2.7; P = .002); and pH less than 7.2 (OR 2.6; P = .009) and age greater than 76 years (OR 2.1; P = .011) more than doubled it.
The investigators then checked their results against the Vascular Study Group of New England Cardiac Index, Glasgow Aneurysm Score, and Edinburgh Ruptured Aneurysm Score. “Our preoperative risk score was most predictive of death, with an area under the curve of 0.76,” Dr. Garland said.
There was no outside funding for the work and Dr. Garland has no disclosures.