Modified Harborview Risk Score improves ease in predicting mortality after ruptured abdominal aortic aneurysm repair

Abstract

ObjectiveThe Harborview Risk Score (HRS) is a simple, accurate 4-point preoperative risk scoring system used to predict 30-day mortality following ruptured abdominal aortic aneurysm (rAAA) repair. The HRS assigns 1 point for each of the following: age >76 years, pH <7.2, creatinine >2 mg/dL, and any episode of severe hypotension (systolic blood pressure <70 mmHg). One potential limitation of this risk scoring system is that arterial blood gas (ABG) analysis is required to determine arterial pH. Because ABG analysis is not routinely performed prior to patient transfer or rAAA repair, we sought to determine if the HRS could be modified by replacing pH with the international normalized ratio (INR), a factor that has been previously shown to have a strong and independent association with 30-day death after rAAA repair. MethodsA retrospective review of all rAAA repairs done at a single academic medical center between January 2002 and December 2018 was performed. Our traditional HRS was compared with a modified score, in which pH <7.2 was replaced with INR >1.8. Patients were included if they underwent rAAA repair (open or endovascular), and if they had preoperative laboratory values available to calculate both the traditional and modified HRS. ResultsDuring the 17-year study period, 360 of 391 repairs met inclusion criteria. Observed 30-day mortality using the modified scoring system was 17% (18/106) for a score of 0 points, 43% (53/122) for 1 point, 54% (52/96) for 2 points, 84% (27/32) for 3 points, and 100% (4/4) for 4 points. Receiver operating characteristic analysis revealed similar ability of the two scoring systems to predict 30-day death: there was no significant difference in the area under the curve (AUC) comparing the traditional (AUC = 0.74) and modified (AUC = 0.72) HRS (P = .3). ConclusionsAlthough previously validated among a modern cohort of patients with rAAA, our traditional 4-point risk score is limited in real-world use by the need for an ABG. Substituting INR for pH improves the usefulness of our risk scoring system without compromising accuracy in predicting 30-day mortality after rAAA repair.