The Least Invasive Fast-Track EVAR (LIFE) registry was created in an attempt to further improve efficiency, outcomes, and cost of endovascular aneurysm repair (EVAR). The study is a prospective multicenter postmarket registry of the ultra-low-profile (14 Fr) Ovation Prime stent graft (Endologix) used in the treatment of patients with abdominal aortic aneurysm (AAA) using a fast-track protocol. Site principal investigator Gavin P. Slethaug, MD, presented details of the registry at the 2016 Annual Scientific Meeting of the Society for Interventional Radiology. Vascular Disease Management spoke with Dr. Slethaug about the study and what the results could mean for the future of EVAR.
VDM: Tell us about your involvement in the study.
Slethaug: There are 2 national co-principal investigators, Zvonimir Krajcer, MD, and Venkatesh Ramaiah, MD, a cardiologist and vascular surgeon respectively, and then there are a number of site principal investigators, of which I am one. We found this registry attractive at our site because the inclusion criteria are very interesting in terms of where we see EVAR going. As an interventional radiologist, I’m especially interested in lower profile percutaneous access. At our site, there are 2 vascular surgeons and 2 interventional radiologists enrolling patients. We have about 10 patients enrolled over the last 5 months.
VDM: What is the most important question this registry aims to answer?
Slethaug: This registry is an opportunity to demonstrate the benefits of low-profile aneurysm repair with very defined criteria. The Ovation device is the lowest profile commercially available device in the United States. The INCRAFT device (Cordis) has essentially the same profile, but it is not yet available. We’re pushing the envelope to make this a minimally invasive procedure.
With the criteria, we are mimicking what we do on a daily basis in the cath lab, interventional radiology lab, or outpatient lab. These are percutaneous cases performed without general anesthesia, and patients will be discharged the next day. There is no intensive care unit admission. What allows us to mimic a procedure done in the lab is the profile, which allows us to feel comfortable and treat the majority of patients who have acceptable inclusion criteria.
VDM: Could you describe the primary and secondary endpoints?
Slethaug: The primary endpoint is major adverse events at 30 days, and there are a number of secondary endpoints that are being gathered. Many of these can then be compared to data that already exist for the Ovation pivotal trial, which studied the safety and efficacy of the Ovation abdominal stent graft (Endologix). One endpoint we can compare is anesthesia. There is a much higher use of regional or local anesthesia in the LIFE study, essentially 100%, whereas this was only 34% in the global Ovation trial.
Another secondary endpoint regards vascular access. All of the patients in the LIFE study are percutaneous because that is part of the study criteria. In the Ovation pivotal trial, only about 43% were treated percutaneously. Additionally, there are a number of interesting and important secondary endpoints that really have impact, especially as we move into a healthcare environment where we’re trying to prove value, control costs, and limit radiation dose as much as possible. We’re looking at fluoroscopy time, procedure time, and blood loss. We’re also looking at length of hospital stay, because that is a significant cost driver.
Secondary endpoints enable a broad multicenter data analysis of EVAR in a least-invasive protocol. The next step we can think about without too much of a stretch, assuming these data come out reasonably – and the midterm results were very reasonable – is to change one of the variables for the criteria. You change next-day discharge to same-day discharge and suddenly you’ve got outpatient EVAR. You need selected patients and good access. You’ve got to watch your comorbidities, and so on. But in a future study, a patient could potentially be on the table at 8 in the morning, kept in a step-down unit for 6 hours, and discharged by 6 pm. If you had suggested this 10 years ago, it would have raised a few eyebrows. At this point, I think it’s a real possibility.
VDM: What are the most important factors in choosing the right patient?
Slethaug: The patient should be able to lie still on your table. With conscious sedation there are a variety of methods, but even though there is no general anesthesia, an anesthesiologist is still involved. There needs to be some dialogue with the anesthesiologist in terms of what type of IV sedation the patient will receive. For example, we had a patient who was moving quite a bit with fentanyl and midazolam but was completely still when we switched to propofol. The patient had multiple comorbidities and was judged to be extremely high risk for general anesthesia. The patient wasn’t enrolled in the study, but percutaneous EVAR (PEVAR) with IV sedation was the safest thing to do.
Reasonable vascular access for percutaneous technique is also important. In the future, when we’re identifying the best class of patients on which to perform a potential outpatient trial, good patient selection with lack of significant comorbidities and good femoral arteries will be key. Patients with significant comorbidities can be treated percutaneously, but it might be best to keep those patients overnight rather than trying to discharge them 6 hours after the procedure.
VDM: Do you think patients with a few more comorbidities may benefit more from the low-profile EVAR than patients without?
Slethaug: Absolutely. We’re getting ahead of ourselves discussing outpatient EVAR, because that’s not what this study was meant to be. But it’s the next question. The patients who will benefit most are those who have a higher risk of general anesthesia; they’ll get outsized benefit from doing this without general anesthesia. One of the things this study was supposed to show is that by using a low-profile device, it’s more feasible to do these cases with just local anesthesia.
VDM: Will that benefit clinicians as well?
Slethaug: Most interventionalists always want to innovate, so treating these patients percutaneously without groin cut-downs is attractive to them. Also, patient satisfaction will increase and the positive word-of-mouth marketing from satisfied patients could drive more volume into that interventionalist’s practice. Another benefit is procedure time. Data are trending toward shorter procedure times for PEVAR. You don’t have to do groin cut-downs to start and you don’t have to do groin closures to finish. Generally you’re going to have shorter procedure times, which will also impact physician and patient satisfaction. In terms of anesthesia, there’s always the possibility of anesthesia delay, intubating patients, extubating patients, and so on. If you don’t have to worry about these issues, cases are faster and there is less risk for complications of general anesthesia, regardless of whether the patient has comorbidities or not.
VDM: Is there a cost savings benefit too?
Slethaug: Absolutely. The midterm results have already shown cost savings. There is less operating room (OR) time. The longer the time spent in the OR, the greater the OR costs, so there’s greater cost savings in terms of OR time. There are also cost savings based on length of stay where the hospital is obviously incurring costs per day, so if you can shorten the number of days spent in the hospital from 3 to 1 or 2 to 1, then your savings are significant. The cost savings need to be calculated taking into account the cost of the closure devices, but even with the slightly increased cost of supplies, the data strongly points to overall cost savings for the procedure and admission as a whole.
VDM: What else would you say was remarkable about the midterm results?
Slethaug: The most interesting things were the length of stay, procedure time, and cost savings. In terms of the primary endpoint, it’s good. There weren’t any major adverse events in the midterm results, but honestly that wasn’t surprising. We know the device works. We’re using the same device that we’ve used before. We’re using the device in what we think is a safer manner, so we weren’t expecting any real issues related to adverse events. The more interesting data are coming from the secondary endpoints.
VDM: Is there anything else that you think vascular clinicians and interventionalists need to know about the design or the current status of the study?
Slethaug: Established data show that PEVAR decreases the risk of groin complications and infections. Also, in addition to benefits for patients and physicians, there are benefits for hospitals and payers. The hospitals should benefit because there are lower infection rates, lower costs of anesthesia, less need for blood transfusion, and overall better use of their resources. Decreased hospital stays aren’t always better for the hospital’s bottom line, but in most cases in a diagnosis-related group payment environment, which we are in, decreased hospital stays translate into decreased cost, and so hospitals are happier. Ultimately, if this can be turned into shorter hospital stays or even ambulatory stays in the future, payers are going to be happier.
Overall, it’s low profile, it’s new, it’s safer, it’s a better patient experience, it’s a better physician experience because you are going to save time and you’re doing things on the cutting edge. You’re going to have improved patient satisfaction and that positive feedback creates good marketing. I think physicians will be excited about it. We’ve certainly seen a move toward PEVAR. It has been done for more than 10 years, but we’ve seen especially in the last few years a significant switch to treating these percutaneously.
Editor’s note: Dr. Slethaug reports payments for educational presentations from Endologix as well as grants to Scottsdale Medical Imaging Research Department for participation in the LIFE Study.