The University of Pennsylvania Medical Center assessed the economic impact experienced by a hospital radiology department when patients underwent stent graft rather than traditional surgical repair for abdominal aortic aneurysms.

The endovascular treatment of abdominal aortic aneurysms, first introduced nearly a decade ago, is gaining acceptance as an alternative treatment for those patients who are at risk for aneurysm rupture, but who are not candidates for conventional surgery. Many patients who previously were believed to be subject to too high a risk to be considered as candidates for aneurysm repair have been treated safely using stent grafts. For these high-risk patients, stent grafts represent the only option that is available to them for the correction of their life-threatening aneurysms. Two devices have recently gained the approval of the US Food and Drug Administration, so it is likely that the pool of patients receiving abdominal aortic stent grafts will expand to include low-risk patients as well.

The trend toward minimally invasive surgery has become well established over the past 2 decades. Patient preference and economic factors have propelled these techniques to the forefront of modern medicine. Less invasive techniques tend to be better tolerated and have quicker recovery periods. This results in shorter hospitalizations and decreased rehabilitation times. Many operations can be performed today safely using endoscopes and balloons rather than knives and sutures.

Endovascular repair of abdominal aortic aneurysms is the latest minimally invasive procedure to be introduced. Patients receiving aortic stent grafts may be discharged a day or two after the procedure while traditional surgical repair patients may be hospitalized for more than a week. While the efficacy of these procedures has yet to be established, one statement can be made for certain: Stent-graft repair of aneurysms represents a major technical and philosophical advance that has revolutionized the way these patients are treated.

There are many differences between endovascular and surgical repair of abdominal aortic aneurysms. Endovascular repair is accompanied by the need for many pre- and postoperative diagnostic and therapeutic radiologic procedures that are not routinely performed in patients undergoing traditional surgical repair.

Preoperatively, patients who will undergo stent grafting receive both CT and conventional angiography. These studies are needed to assist in determination of the correct type and configuration of the endograft. Patients may also undergo preoperative embolization of aortic branch vessels in order to prevent retrograde filling of the aneurysm sac once the graft is in place. Intraoperatively, patients often require additional embolizations and/or angioplasties to introduce and seal the device. Postoperatively, stent-graft patients require CT angiograms at regular intervals in order to ensure that the endograft is preventing blood from flowing into the aneurysm sac. If such a leak is identified, additional procedures are performed to correct it.

In contrast, fewer radiologic procedures precede traditional surgical repair of an abdominal aortic aneurysm, and there is no intraoperative imaging. After traditional surgical repair, the only imaging procedure that is required is a yearly follow-up ultrasound examination. Therefore, even though the endovascular repair of abdominal aortic aneurysms appears to be less morbid, many more radiologic procedures are performed for patients having endovascular repair than for patients undergoing traditional surgical repair.

The purpose of the investigation undertaken at the University of Pennsylvania Medical Center, Philadelphia, was to assess the economic impact experienced by a hospital radiology department when patients underwent stent grafting rather than traditional surgical repair for abdominal aortic aneurysms. The aortic stent-graft program at the University of Pennsylvania is a collaborative effort between the divisions of vascular surgery and interventional radiology. Patients are enrolled in one of eight clinical trials or receive either of the approved devices. Volume ranges from four to six cases a week.


In order to assess the economic impact of our stent-graft program on the radiology department, the billing records of two cohorts of patients were examined. The first group consisted of 63 patients with abdominal aortic aneurysms who underwent endovascular repair. The second group consisted of 63 patients who underwent traditional surgical repair of their abdominal aortic aneurysms. The patient demographics and comorbidities of the two groups were essentially identical. All diagnostic imaging and interventional procedures performed in the Department of Radiology and directly related to the preoperative and postoperative evaluation and treatment of the abdominal aortic aneurysms were recorded; these procedures included ultrasound studies, CT examinations, MRI studies, diagnostic angiography, embolization, stent placement, angioplasty, and thrombolysis. Corresponding work relative value units (RVUs) were assigned based on Current Procedural Terminology, 4th edition procedure codes for each examination. The total work RVUs and mean work RVUs per patient were calculated for each group, and the results for the two groups were then compared. Work RVUs for the abdominal aortic stent-graft procedure itself were identified, kept separate, and not included in the calculations.


In the stent-graft group, 172 CT angiograms, 12 magnetic resonance angiograms (MRAs), 65 diagnostic angiograms, 25 embolizations, two iliac stents, one thrombolysis, and one angioplasty of an occluded stent-graft limb were performed. The total of work RVUs for this cohort was 1,216.72, while the calculated mean per-patient work RVU number was 19.31. See Figure 1.

In the open-repair group, 34 CT angiograms, 19 MRAs, 38 diagnostic angiograms, and two diagnostic ultrasound procedures were performed. No interventional procedures were performed for the patients in this group. Work RVUs for this cohort totaled 224.36, and the calculated mean work RVUs per patient were 3.56. Comparison of the two groups shows that there are 5.4 times as many work RVUs associated with the radiologic studies needed if a patient undergoes endovascular repair of an abdominal aortic aneurysm as there are if traditional surgical repair methods are employed. See Figure 2.


Radiologic work RVUs generated by patients undergoing stent-graft treatment of abdominal aortic aneurysms exceeded the work RVUs generated by patients undergoing traditional surgical repair by a factor of five. This results in a significant economic impact on the radiology department. Economic issues between surgeons and radiologists may be difficult to overcome at first, but, at present, stent grafts represent revenue sources for both groups. Outreach to referring physicians regarding the University of Pennsylvania Medical Center’s stent-graft program resulted in a threefold increase in AAA referrals In addition, many patients who are not candidates for traditional surgical reconstruction because of various comorbidities may be safely repaired using stent grafts. Radiologists benefit from the increased imaging RVUs associated with endovascular repair of abdominal aortic aneurysms. Cooperation between specialties (and between physicians and the hospital) is the key to implementation of a successful stent-graft program that will benefit all parties involved.

Richard A. Baum, MD, is an interventional radiologist, and Ronald Fairman, MD, and Jeffrey Carpenter, MD are vascular surgeons at the University of Pennsylvania Medical Center, Philadelphia.