- Email: [email protected]
Cost Impact of Extension Cuff Utilization During Endovascular Aneurysm Repair
Cost Impact of Extension Cuff Utilization During Endovascular Aneurysm Repair Venita Chandra, Joshua I. Greenberg, Weesam K. Al-Khatib, E. John Harris, Ronald L. Dalman, and Jason T. Lee, Stanford, California
Background: Modular stent-graft systems for endovascular aneurysm repair (EVAR) most often require two to three components, depending on the device. Differences in path lengths and availability of main body systems often require additional extensions for appropriate aneurysm exclusion. These additional devices usually result in added expenses and can affect the financial viability of an EVAR program within a hospital. The purpose of this study was to analyze the use of extensions during EVAR, focusing on incidence, clinical impact, and financial impact, as well as determining the associated cost differences between two- and three-component EVAR device systems. Methods: We reviewed available clinical data, images, and follow-up of 218 patients (203 males and 15 females, mean age: 74 ± 9 years) who underwent elective EVAR at a single academic center from 2004 to 2007. Patients were divided into two groups: patients undergoing EVAR using the standard number of pieces, that is, no extensions used (group A, n ¼ 98), and those needing proximal or distal extensions during the index procedure (group B, n ¼ 120). Results: Both groups were similar in terms of demographics; preoperative characteristics, including aneurysm morphology; as well as intraoperative, postoperative, and midterm outcomes. Overall, 30-day operative mortality was 1.4%, with a mean follow-up of 24 months. Group A patients underwent repair with two-piece modular devices 41% of the time and three-piece systems 59% of the time, whereas group B patients underwent repair with twopiece modular systems 82% of the time and three-piece modular systems 18% of the time. The number of additional extensions per patient ranged from one to four (median: one piece). There was a 30% cost increase in overall mean device-related cost when using extensions versus the standard number of pieces (group A: $13,220 vs. group B: $17,107, p < 0.01). Conclusions: Clinical midterm aneurysm-related outcomes after EVAR in patients who required additional extensions was comparable with those treated with the standard number of pieces. An increased number of extensions led to increased costs and could have potentially been minimized with appropriate preoperative planning or device selection. Consideration should be made toward per-case pricing instead of per-piece pricing to further improve cost efficiency without compromising long-term patient outcomes.
INTRODUCTION Health care cost efficiency has become an increasingly important issue in the current economic climate, especially as more focus has been placed Presented at the 21st Annual Winter Meeting of the Peripheral Vascular Surgery Society, Steamboat Springs, CO, January 28-30, 2011. Division of Vascular Surgery, Stanford University Medical Center, Stanford, CA. Correspondence to: Jason T. Lee, MD, Division of Vascular Surgery, 300 Pasteur Drive, Suite H3600, Stanford, CA 94305, USA, E-mail: [email protected] Ann Vasc Surg 2012; 26: 86-92 DOI: 10.1016/j.avsg.2011.10.003 Ó Annals of Vascular Surgery Inc.
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on the rising costs of health care in the United Statesdthe most expensive health care system in the world. Many argue technologic innovation is a major factor associated with increased costs as compared with established treatment methods.1,2 Accordingly, with the endovascular revolution we have witnessed this past decade, there has been associated discussion regarding the economic benefit or burden of endovascular techniques, particularly with regard to endovascular abdominal aortic aneurysm repair (EVAR), which has rapidly replaced open surgery as the more common and preferred method of routine and emergent abdominal aneurysm repair.3
Vol. 26, No. 1, January 2012
Cost analyses of endovascular versus open procedures are often quite complicated and limited in their predictive capabilities. Challenges include the multifactorial influences on total expense of care, including actual device costs, professional billing, hospital billing and length of stay, and cost of follow-up imaging. Previous reports have studied the associated costs of EVAR and consistently document a higher cost of EVAR in comparison with open repair.2,4-7 These cost differences mostly are primarily driven by the cost of the endograft device itself, with 47-78% of total inpatient hospital costs after aneurysm repair because of device charges.2,6-9 Within surgeon control perhaps is the attempt to optimize device costs or utilization, and might therefore be a reasonable strategy to control costs. Because EVAR devices are often modular stentgraft systems requiring several components or pieces, planning issues or path length differences often lead to necessary additional extensions for appropriate exclusion of the aneurysm. These additional devices when used result in added expenses and can affect the financial viability of an EVAR program within a hospital. The purpose of this study was to analyze the use of extensions during EVAR, focusing on incidence, clinical impact, and financial impact, as well as determining the associated cost differences between two- and three-component EVAR device systems.
METHODS We retrospectively reviewed a prospectively managed database of consecutive patients who underwent EVAR during a 4-year period (2004-2007) performed at a single academic medical center. To obtain a more standardized patient population, we excluded cases that involved more complex endovascular solutions, such as ruptures, ‘‘snorkel’’ techniques, hybrid procedures, or debranching, as well as patients involved in studies or industry-sponsored clinical trials. Patient demographics, abdominal aortic aneurysm characteristics, and intra- and postoperative characteristics were all entered into the database prospectively. Endograft systems used at our institution during the study period included those that were Food and Drug Administration-approved at the time, namely Cook Zenith (Cook Incorporated, Bloomington, IN), Gore Excluder (W. L. Gore & Associates, Inc., Flagstaff, AZ), and Medtronic AneuRx (Medtronic Vascular, Santa Rosa, CA) devices. The specific device chosen for each case was determined
Extension piece utilization during EVAR 87
by patient anatomy, surgeon preference, and device availability. The need for extensions was decided by the primary surgeon either before or during the procedure, depending on the particular stent-graft system to be used. Preoperative planning was often performed on a three-dimensional workstation (TeraRecon, Mountain View, CA) by the attending surgeon and the vascular trainee. Procedures were performed in the operating room with a portable C-arm or in a dedicated cath lab endovascular suite. Postoperative care was mostly in a monitored surgical ward for 24-48 hours and then discharge to home. Follow-up was relatively standardized at our institution, and it included cross-sectional imaging and/or duplex ultrasonography at 1 month, 6 months, and annually. For cost calculations to focus specifically on device use and extensions, we did not include hospital billing, collections, or physician charges. Instead, we focused on the cost of device our institution was charged based on the endograft components implanted during the case, prices are listed in Table I and are current for the academic year 2010. For the purposes of analysis, we divided the patient cohort into two main groups. Group A included patients who underwent EVAR without the need for extensions based on their main body endograft system. For example, if the case was done using the Gore Excluder or Medtronic AneuRx, group A only had a main body endograft plus one contralateral limb placed, or if they had a Cook Zenith, group A had a main body and two iliac limbs placed. Group B consisted of patients from the study cohort requiring placement of at least one or more proximal or distal extensions, beyond the ‘‘standard’’ number of pieces for twoor three-piece systems. Additional analyses performed divided the cohort into two-piece modular systems versus three-piece modular systems. All data were collected and statistical analyses performed using Excel 2007 (Microsoft Corp., Redmond, WA). The Wilcoxon rank sum test or Fisher exact test was used to test for statistical differences between groups, where appropriate, with values of p < 0.05 considered significant.
RESULTS Between January 2004 and December 2007, 501 patients underwent aneurysm repair at our institution. Of these, 326 (65%) underwent EVAR, with 108 (33%) of the EVAR patients being involved in ruptured, complex hybrid procedures, or enrolled in clinical trials. This left 218 patients who
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Table I. Device costs at our institution Device
Cost
Medtronic AneuRx main body Medtronic AneuRx limb extension Medtronic AneuRx proximal extension Gore Excluder main body Gore Excluder limb extension Gore Excluder proximal extension Cook Zenith main body Cook Zenith limb extension Cook Zenith proximal extension
$7,500 $3,200 $2,800 $8,370 $3,865 $2,710 $8,370 $2,996 $1,885
underwent ‘‘standard’’ elective EVAR at our institution and were included in this cost analysis study. Of this cohort of 218 patients, 28% received AneuRx devices, 36% received Excluder devices, and 36% received Zenith devices. When divided by extension device use, 98 (45%) underwent EVAR without the use of extensions (group A), and 120 (55%) had EVAR requiring the use of planned or unplanned extension pieces (group B). Of those without extensions (group A), 9% had AneuRx, 32% had Excluder, and 59% had Zenith devices. Among group B patients, who required additional extensions, 44% received AneuRx devices, 39% received Excluder devices, and 17% received Zenith devices. Overall, there were 173 distal extensions and 14 proximal ones placed. Of the proximal extensions, five of them (36%) were placed in patients with aneurysms with short necks (10-15 mm). Patient demographics, including age, sex, comorbidities, and preoperative aneurysm morphology, were similar between the two groups (Table II). Intraoperative and postoperative courses, including fluoroscopy time, length of stay, complications, and perioperative mortality, were also similar between the two groups, although there was a small, but significant, increase in estimated blood loss in group B compared with group A (Table III). Mean followup time was 23.9 months, and there was no significant difference in follow-up between the two groups. In addition, there was no significant difference in terms of other midterm outcomes, including migration, endoleak rate, amount of sac regression, or need for reinterventions at latest follow-up (Table III). The total mean device cost of stent-graft systems for the entire cohort was $15,344. For patients in group A (those who did not require the use of extensions), the mean device costs were $13,220, whereas those in group B had a significantly higher mean device cost of $17,107 ( p < 0.05, Fig. 1). When looking at group A, which would be the ideal treatment group using the standard number of
pieces, there was a lower device cost for those patients who received two-piece modular systems (41% of patients) as compared with those who received three-piece modular systems (59% of patients). However, when one includes group B and divides the cohort by two-piece modular EVAR (65% of patients) versus three-piece modular EVAR (36% of patients), we no longer witness the cost advantage for the two-piece system (Table IV). Focusing on group B patients requiring extensions, there was no significant difference in terms of the mean device costs between patients receiving two-piece modular systems (82% of patients) compared with those receiving three-piece modular systems (18% of patients), although there was an overall 30% increase in total mean costs compared with group A (Table IV). This cost change for group B was due to the fact that many more patients in this group initially had two-piece modular systems as opposed to three-piece modular systems (99 vs. 21). The requirement for distal extension cuffs in the two-piece system cohort drove up their costs. Only one of the patients who had three-piece modular system required more than one extension, whereas as many as 52% of patients who had AneuRx devices and 21% of patients who had Excluder devices required two or more extensions. Of the patients who had two-piece modular systems and required placement of extensions, 47% required bilateral iliac extenders, 19% had contralateral limb extenders, and 34% had ipsilateral limb extenders. Analyses between device manufacturers revealed extension utilization and cost differences. Overall, there was no significant difference between patients who had AneuRx devices compared with those who had Excluder devices implanted. In addition, there was also no significant difference when comparing Excluder patients with Zenith patients; there was, however, a small, but significant, difference when comparing total device costs of patients with AneuRx devices with those who had Zenith devices implanted (Table V).
DISCUSSION We demonstrated in this study that more than half of patients undergoing standard EVAR require proximal or distal extension piece placement for appropriate aneurysm exclusion with acceptable midterm results. There were no differences in peri- or postoperative outcomes noted between patients requiring extensions and those with
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Extension piece utilization during EVAR 89
Table II. Demographics and preoperative AAA characteristics Parameter
Demographics Number of patients (% total) Age Female Comorbidities CAD CRI HTN COPD DM CHF Preoperative AAA characteristics Maximum AAA diameter (mm) Neck length % Short neck (10-15 mm) Neck diameter (mm) Iliac diameter (mm) % With associated iliac aneurysm
Total n ¼ 218
Group A n ¼ 98 (no extenders)
Group B n ¼120 (extenders used)
p (<0.05)
218 73.9 6.9%
98 (45%) 72.7 9.2%
120 (55%) 75.0 5.2%
e NS NS
54.6% 16.5% 72.9% 22.5% 17.4% 11.5%
54.1% 19.4% 77.6% 21.4% 19.4% 13.3%
55.0% 14.2% 69.2% 23.3% 15.8% 10.0%
NS NS NS NS NS NS
58.5 24.1 10.6% 23.4 19.4 24.8%
58.0 23.6 14.3% 23.5 18.3 21.4%
59.0 24.6 7.5% 23.3 20.6 27.5%
NS NS NS NS NS NS
No significant difference between group A (patients who did not have extensions) and group B (patients that did require extensions) in terms of demographics, comorbidities, or preoperative AAA characteristics. AAA, abdominal aortic aneurysm; CAD, coronary artery disease; CRI, chronic renal insufficiency; HTN, hypertension; COPD, chronic obstructive pulmonary disease; DM, diabetes mellitus; CHF, congestive heart failure.
Table III. Intraoperative and postoperative course Parameter
Total n ¼ 218
Intraoperative and postoperative course Estimated blood loss (mL) 358 Fluoroscopy time (minute) 27.0 IV contrast (mL) 118 Length of stay (days) 5.4 30-day mortality 1.4% Complications Cardiovascular 4.6% Wound 11.9% Renal 5% Midterm outcomes Migration >10 mm 2.3% Any endoleak (all types) 41.7% % Type I endoleak 5.5% % Reinterventions 16.5% Sac regression (mm) 5.1 Follow-up time (months) 23.9
Group A n ¼ 98 (no extenders)
Group B n ¼120 (extender used)
p (<0.05)
301 27.9 115 5.1 2%
383 26.5 121 5.7 0.8%
0.03 NS NS NS NS
5.1% 10.2% 4.1%
4.2% 13.4% 5.8%
NS NS NS
1% 38.8% 5.1% 19.4% 6.1 24.8
3.3% 44.2% 5.8% 14.2% 4.4 22.7
NS NS NS NS NS NS
No significant difference between group A (patients who did not have extensions) and group B (patients who did require extensions), except for a small, but significant, difference in estimated blood loss.
standard number of components placed. When extensions were used, the device-associated cost of the procedure was significantly higher by approximately 30%. Modular two-component EVAR systems more often required extensions than three-component systems (71% vs. 27%), but the cost between these two types of device
systems in aggregate was not significantly different. The least costly solution when it occurred was a two-piece system without extensions, although the planned three-piece system did consistently provide the highest likelihood of lower costs because of lack of need for extensions, and therefore, suggests potential manufacturer-specific
90 Chandra et al.
Fig. 1. Total mean device costs. Total mean devices costs in group B (patients who received extensions) were significantly more than those in group A (patients who did not receive extensions). In patients who were in group A, total mean devices costs were significantly
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higher in those patients who received three-piece modular devices as opposed to two-piece modular devices. This difference between two- and three-piece device costs is not seen in group B patients.
Table IV. Comparison of two- and three-piece endograft systems in group B (patients who required extensions) Group B (extenders used)
Two-piece devices
Three-piece devices
p (<0.05)
Number of patients Number of proximal extenders Number of distal extenders Total number of extenders Total device cost Cost of extenders per case (percent of total cost)
99 5 160 165 $17,125 $5,712 (33%)
21 9 13 22 $16,866 $2,662 (11%)
e 0.0001 0.0001 e NS <0.0001
Significantly more proximal extenders used in the patients who received three-piece devices, although overall not many proximal devices were used. Significantly more distal extenders were used in the patients who received two-piece devices. In terms of the total mean device cost, there is no significant difference between two- and three-piece modular systems; however, the average cost of extenders per case in three-piece device systems is only $2,662, which is significantly less than the $5,712 of two-piece systems.
advantages of certain devices over others when considering device costs. The focus on rising health care costs has not escaped the vascular surgery literature, with the number of publications in PubMed on cost for vascular surgical procedures quadrupling since 1990.10 With EVAR being one of the most wellaccepted procedures done by our specialty, many studies have compared EVAR versus open repair in terms of costs. Despite clinical advantages of EVAR, including lower perioperative mortality and
length of stay, the reliance for follow-up imaging and device-related costs drive up the total cost of repair when comparing EVAR with open repair. Feezor et al.11 reported on the University of Florida experience, which mirrors our findings. The highest number of extensions used was with the AneuRx device (two-piece system), and the fewest number of extensions with the Zenith device (three-piece system), offsetting the initial cost advantage of the AneuRx endograft system. They concluded that although there was no manufacturer-specific
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Extension piece utilization during EVAR 91
Table V. Comparison of different device manufacturers Parameter
AneuRx n ¼ 61
Excluder n ¼ 78
Zenith n ¼ 79
% Needing extenders Number of extensions per case % Requiring one extension % Requiring two extensions % Requiring three extensions % Requiring four or more extensions Total costs of extensions Total device costs
84% 1.6 32% 38% 10% 4% $5,036 $15,736
58% 0.8 37% 18% 2% 1% $3,310 $15,477
25% 0.3 22% 3% 0 0 $707 $14,912
advantage in their cohort, device costs could be minimized with careful planning and choosing proper devices for patients’ anatomy. We believe that minimizing costs without compromising long-term patient outcomes is an ideal solution and should be attempted when feasible. For EVAR, that translates into using the fewest components possible without compromising aneurysm exclusion, and therefore, will be anatomy dependent. In another study of thoracic endografting, it was also confirmed that the number of device components implanted accounted for the majority (nearly 75%) of the overall cost of TEVAR.3 Using data from a multicenter trial that was used to obtain initial approval for EVAR, Sternbergh and Money5 found inpatient costs of EVAR were nearly $20,000, as compared with $12,500 for open repair. This did not even account for the postoperative follow-up necessary for EVAR, particularly with regard to costly computed tomography angiography. A multicenter review of EVAR by Bertges et al.2 in the early 2000s found that hospital costs often exceeded the diagnosis-related group for routine aneurysm repair, suggesting EVAR might even be a losing proposition in many hospitals. We all understand, however, that costs and reimbursement are often two separate entities, and can depend on a lot of local factors, including contracts, state politics, and manufacturer issues. Still, the recurrent theme in most cost analysis literature for EVAR is that more than 50% of the ‘‘cost’’ of EVAR is from the device. We therefore suggest that strategies to minimize the likelihood of the need for unplanned or unnecessary extension pieces are a surgeon-controllable factor, and this was the impetus for us to carry out this analysis in our own practice. When looking at our institutional use of extension pieces by individual manufactured device, we discovered when certain device manufacturers were used, namely AneuRx devices, that extensions
were needed 84% of the time. This was in comparison with 58% for Excluder devices and only 25% when Zenith devices were used. Acknowledging that rising costs and the need to be more efficient was important, we have since altered our practice by trying to match anatomy to certain two- versus three-stent endograft systems. Therefore, when preoperative planning suggests that a two-piece system will require bilateral distal extensions (e.g., when an extension is needed to cover the entire length of the common iliac up to the bifurcation), then we prefer to use a three-piece modular stentgraft system. On the flip side, if a two-piece system without extenders is feasible, given a patient’s anatomy, that is still considered the most costeffective. Exact reasons why extensions were used in each case are difficult to determine in this retrospective review of cases. Further clarification in terms of the reasoning or indications for extension piece use could help in terms of cost containment and adjusting practices to minimize the use of excessive or unnecessary devices. Discussions have also begun within our group with the device manufacturers to provide per-case pricing rather than per-piece pricing as another strategy to control overall costs of EVAR. Careful attention to these issues can potentially help keep the financial viability of our EVAR program, particularly with the increasing concerns about rising health care costs. Our study has several limitations. First, we focused only on device costs, which assess only one element of total EVAR costs. This neglects the many other aspects, including inpatient charges, intensive care unit stays, operating room costs, and follow-up costs. Also, our analysis of device costs is estimated based on list prices determined at the time of this study. It is possible that this determination could be over- or underestimating actual device costs, although likely balances out both groups equally. In addition, given the fact that the
92 Chandra et al.
preoperative planning and the intraoperative decision making was at the discretion of the staff surgeon, we do not have preoperative sizing sheets available for our analysis. Thus, it is challenging to clarify the exact amount of impact surgeon preference and experience led to the variability seen in these reported results, and also to determine exactly what percentage of extensions was planned versus determined intraoperatively. Again, we think these limitations should equally affect both groups, and wished to analyze our ‘‘real world’’ ability to control costs from a device standpoint. Finally, cost analysis at a single institution is not necessarily universally applicable, and we suggest other groups perform similar analyses to understand what their EVAR practice is costing in terms of device choices and extension piece utilization.
CONCLUSIONS Fifty-five percent of EVAR cases in our institution required the use of extension pieces, which resulted in an approximately 30% increase in total device costs. Although the main focus during EVAR should be the best clinical outcome with appropriate and adequate exclusion of the entire aneurysm, efforts and strategies to be cost-efficient can be effectively implemented. Given the high price of endograft components, each additional device extension is associated with an increase in total cost; this could potentially be minimized by better preoperative planning, and possibly by manufacturer-specific selection. In addition, negotiations with vendors could be considered to include alternatives in
Annals of Vascular Surgery
consignment and purchasing programs, including per-case pricing instead of per-piece pricing. REFERENCES 1. Bodenheimer T. High and rising health care costs. Part 2: technologic innovation. Ann Intern Med 2005;142:932-937. 2. Bertges DJ, Zwolak RM, Deaton DH, et al. Current hospital costs and Medicare reimbursement for endovascular abdominal aortic aneurysm repair. J Vasc Surg 2003;37:272-279. 3. Walker KL, Lipori P, Lee WA, et al. Cost of thoracic endovascular aortic repair versus open repair and implications for the US health care system. J Thorac Cardiovasc Surg 2010;139:231-232. 4. Patel ST, Haser PB, Bush HL, et al. The cost-effectiveness of endovascular repair versus open surgical repair of abdominal aortic aneurysms: a decision analysis model. J Vasc Surg 1999;29:958-972. 5. Sternbergh WC, Money SR. Hospital cost of endovascular versus open repair of abdominal aortic aneurysms: a multicenter study. J Vasc Surg 2000;31:237-244. 6. Clair DG, Gray B, O’hara PJ, et al. An evaluation of the costs to health care institutions of endovascular aortic aneurysm repair. J Vasc Surg 2000;32:148-152. 7. Paraskevas KI, Bessias N, Giannoukas AD, Mikhailidis DP. Endovascular abdominal aortic aneurysm repair (EVAR) procedures: counterbalancing the benefits with the costs. Vasc Endovascular Surg 2010;44:319-320. 8. Kim JK, Tonnessen BH, Noll RE, et al. Reimbursement of long-term post placement costs after endovascular abdominal aortic aneurysm repair. J Vasc Surg 2008;48:1390-1395. 9. Angle N, Dorafshar AH, Moore WS, et al. Open versus endovascular repair of abdominal aortic aneurysms: what does each really cost? Ann Vasc Surg 2004;18:612-618. 10. Mani K, Lundkvist J, Holmberg L, et al. Challenges in analysis and interpretation of cost data in vascular surgery. J Vasc Surg 2010;51:148-154. 11. Feezor RJ, Huber TS, Berceli SA, Nelson PR, Seeger JM, Lee WA. Impact of endograft design and product line on the device cost of endovascular aneurysm repair. J Vasc Surg 2008;47:499-503.
Background: Modular stent-graft systems for endovascular aneurysm repair (EVAR) most often require two to three components, depending on the device. Differences in path lengths and availability of main body systems often require additional extensions for appropriate aneurysm exclusion. These additional devices usually result in added expenses and can affect the financial viability of an EVAR program within a hospital. The purpose of this study was to analyze the use of extensions during EVAR, focusing on incidence, clinical impact, and financial impact, as well as determining the associated cost differences between two- and three-component EVAR device systems. Methods: We reviewed available clinical data, images, and follow-up of 218 patients (203 males and 15 females, mean age: 74 ± 9 years) who underwent elective EVAR at a single academic center from 2004 to 2007. Patients were divided into two groups: patients undergoing EVAR using the standard number of pieces, that is, no extensions used (group A, n ¼ 98), and those needing proximal or distal extensions during the index procedure (group B, n ¼ 120). Results: Both groups were similar in terms of demographics; preoperative characteristics, including aneurysm morphology; as well as intraoperative, postoperative, and midterm outcomes. Overall, 30-day operative mortality was 1.4%, with a mean follow-up of 24 months. Group A patients underwent repair with two-piece modular devices 41% of the time and three-piece systems 59% of the time, whereas group B patients underwent repair with twopiece modular systems 82% of the time and three-piece modular systems 18% of the time. The number of additional extensions per patient ranged from one to four (median: one piece). There was a 30% cost increase in overall mean device-related cost when using extensions versus the standard number of pieces (group A: $13,220 vs. group B: $17,107, p < 0.01). Conclusions: Clinical midterm aneurysm-related outcomes after EVAR in patients who required additional extensions was comparable with those treated with the standard number of pieces. An increased number of extensions led to increased costs and could have potentially been minimized with appropriate preoperative planning or device selection. Consideration should be made toward per-case pricing instead of per-piece pricing to further improve cost efficiency without compromising long-term patient outcomes.
INTRODUCTION Health care cost efficiency has become an increasingly important issue in the current economic climate, especially as more focus has been placed Presented at the 21st Annual Winter Meeting of the Peripheral Vascular Surgery Society, Steamboat Springs, CO, January 28-30, 2011. Division of Vascular Surgery, Stanford University Medical Center, Stanford, CA. Correspondence to: Jason T. Lee, MD, Division of Vascular Surgery, 300 Pasteur Drive, Suite H3600, Stanford, CA 94305, USA, E-mail: [email protected] Ann Vasc Surg 2012; 26: 86-92 DOI: 10.1016/j.avsg.2011.10.003 Ó Annals of Vascular Surgery Inc.
86
on the rising costs of health care in the United Statesdthe most expensive health care system in the world. Many argue technologic innovation is a major factor associated with increased costs as compared with established treatment methods.1,2 Accordingly, with the endovascular revolution we have witnessed this past decade, there has been associated discussion regarding the economic benefit or burden of endovascular techniques, particularly with regard to endovascular abdominal aortic aneurysm repair (EVAR), which has rapidly replaced open surgery as the more common and preferred method of routine and emergent abdominal aneurysm repair.3
Vol. 26, No. 1, January 2012
Cost analyses of endovascular versus open procedures are often quite complicated and limited in their predictive capabilities. Challenges include the multifactorial influences on total expense of care, including actual device costs, professional billing, hospital billing and length of stay, and cost of follow-up imaging. Previous reports have studied the associated costs of EVAR and consistently document a higher cost of EVAR in comparison with open repair.2,4-7 These cost differences mostly are primarily driven by the cost of the endograft device itself, with 47-78% of total inpatient hospital costs after aneurysm repair because of device charges.2,6-9 Within surgeon control perhaps is the attempt to optimize device costs or utilization, and might therefore be a reasonable strategy to control costs. Because EVAR devices are often modular stentgraft systems requiring several components or pieces, planning issues or path length differences often lead to necessary additional extensions for appropriate exclusion of the aneurysm. These additional devices when used result in added expenses and can affect the financial viability of an EVAR program within a hospital. The purpose of this study was to analyze the use of extensions during EVAR, focusing on incidence, clinical impact, and financial impact, as well as determining the associated cost differences between two- and three-component EVAR device systems.
METHODS We retrospectively reviewed a prospectively managed database of consecutive patients who underwent EVAR during a 4-year period (2004-2007) performed at a single academic medical center. To obtain a more standardized patient population, we excluded cases that involved more complex endovascular solutions, such as ruptures, ‘‘snorkel’’ techniques, hybrid procedures, or debranching, as well as patients involved in studies or industry-sponsored clinical trials. Patient demographics, abdominal aortic aneurysm characteristics, and intra- and postoperative characteristics were all entered into the database prospectively. Endograft systems used at our institution during the study period included those that were Food and Drug Administration-approved at the time, namely Cook Zenith (Cook Incorporated, Bloomington, IN), Gore Excluder (W. L. Gore & Associates, Inc., Flagstaff, AZ), and Medtronic AneuRx (Medtronic Vascular, Santa Rosa, CA) devices. The specific device chosen for each case was determined
Extension piece utilization during EVAR 87
by patient anatomy, surgeon preference, and device availability. The need for extensions was decided by the primary surgeon either before or during the procedure, depending on the particular stent-graft system to be used. Preoperative planning was often performed on a three-dimensional workstation (TeraRecon, Mountain View, CA) by the attending surgeon and the vascular trainee. Procedures were performed in the operating room with a portable C-arm or in a dedicated cath lab endovascular suite. Postoperative care was mostly in a monitored surgical ward for 24-48 hours and then discharge to home. Follow-up was relatively standardized at our institution, and it included cross-sectional imaging and/or duplex ultrasonography at 1 month, 6 months, and annually. For cost calculations to focus specifically on device use and extensions, we did not include hospital billing, collections, or physician charges. Instead, we focused on the cost of device our institution was charged based on the endograft components implanted during the case, prices are listed in Table I and are current for the academic year 2010. For the purposes of analysis, we divided the patient cohort into two main groups. Group A included patients who underwent EVAR without the need for extensions based on their main body endograft system. For example, if the case was done using the Gore Excluder or Medtronic AneuRx, group A only had a main body endograft plus one contralateral limb placed, or if they had a Cook Zenith, group A had a main body and two iliac limbs placed. Group B consisted of patients from the study cohort requiring placement of at least one or more proximal or distal extensions, beyond the ‘‘standard’’ number of pieces for twoor three-piece systems. Additional analyses performed divided the cohort into two-piece modular systems versus three-piece modular systems. All data were collected and statistical analyses performed using Excel 2007 (Microsoft Corp., Redmond, WA). The Wilcoxon rank sum test or Fisher exact test was used to test for statistical differences between groups, where appropriate, with values of p < 0.05 considered significant.
RESULTS Between January 2004 and December 2007, 501 patients underwent aneurysm repair at our institution. Of these, 326 (65%) underwent EVAR, with 108 (33%) of the EVAR patients being involved in ruptured, complex hybrid procedures, or enrolled in clinical trials. This left 218 patients who
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Table I. Device costs at our institution Device
Cost
Medtronic AneuRx main body Medtronic AneuRx limb extension Medtronic AneuRx proximal extension Gore Excluder main body Gore Excluder limb extension Gore Excluder proximal extension Cook Zenith main body Cook Zenith limb extension Cook Zenith proximal extension
$7,500 $3,200 $2,800 $8,370 $3,865 $2,710 $8,370 $2,996 $1,885
underwent ‘‘standard’’ elective EVAR at our institution and were included in this cost analysis study. Of this cohort of 218 patients, 28% received AneuRx devices, 36% received Excluder devices, and 36% received Zenith devices. When divided by extension device use, 98 (45%) underwent EVAR without the use of extensions (group A), and 120 (55%) had EVAR requiring the use of planned or unplanned extension pieces (group B). Of those without extensions (group A), 9% had AneuRx, 32% had Excluder, and 59% had Zenith devices. Among group B patients, who required additional extensions, 44% received AneuRx devices, 39% received Excluder devices, and 17% received Zenith devices. Overall, there were 173 distal extensions and 14 proximal ones placed. Of the proximal extensions, five of them (36%) were placed in patients with aneurysms with short necks (10-15 mm). Patient demographics, including age, sex, comorbidities, and preoperative aneurysm morphology, were similar between the two groups (Table II). Intraoperative and postoperative courses, including fluoroscopy time, length of stay, complications, and perioperative mortality, were also similar between the two groups, although there was a small, but significant, increase in estimated blood loss in group B compared with group A (Table III). Mean followup time was 23.9 months, and there was no significant difference in follow-up between the two groups. In addition, there was no significant difference in terms of other midterm outcomes, including migration, endoleak rate, amount of sac regression, or need for reinterventions at latest follow-up (Table III). The total mean device cost of stent-graft systems for the entire cohort was $15,344. For patients in group A (those who did not require the use of extensions), the mean device costs were $13,220, whereas those in group B had a significantly higher mean device cost of $17,107 ( p < 0.05, Fig. 1). When looking at group A, which would be the ideal treatment group using the standard number of
pieces, there was a lower device cost for those patients who received two-piece modular systems (41% of patients) as compared with those who received three-piece modular systems (59% of patients). However, when one includes group B and divides the cohort by two-piece modular EVAR (65% of patients) versus three-piece modular EVAR (36% of patients), we no longer witness the cost advantage for the two-piece system (Table IV). Focusing on group B patients requiring extensions, there was no significant difference in terms of the mean device costs between patients receiving two-piece modular systems (82% of patients) compared with those receiving three-piece modular systems (18% of patients), although there was an overall 30% increase in total mean costs compared with group A (Table IV). This cost change for group B was due to the fact that many more patients in this group initially had two-piece modular systems as opposed to three-piece modular systems (99 vs. 21). The requirement for distal extension cuffs in the two-piece system cohort drove up their costs. Only one of the patients who had three-piece modular system required more than one extension, whereas as many as 52% of patients who had AneuRx devices and 21% of patients who had Excluder devices required two or more extensions. Of the patients who had two-piece modular systems and required placement of extensions, 47% required bilateral iliac extenders, 19% had contralateral limb extenders, and 34% had ipsilateral limb extenders. Analyses between device manufacturers revealed extension utilization and cost differences. Overall, there was no significant difference between patients who had AneuRx devices compared with those who had Excluder devices implanted. In addition, there was also no significant difference when comparing Excluder patients with Zenith patients; there was, however, a small, but significant, difference when comparing total device costs of patients with AneuRx devices with those who had Zenith devices implanted (Table V).
DISCUSSION We demonstrated in this study that more than half of patients undergoing standard EVAR require proximal or distal extension piece placement for appropriate aneurysm exclusion with acceptable midterm results. There were no differences in peri- or postoperative outcomes noted between patients requiring extensions and those with
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Extension piece utilization during EVAR 89
Table II. Demographics and preoperative AAA characteristics Parameter
Demographics Number of patients (% total) Age Female Comorbidities CAD CRI HTN COPD DM CHF Preoperative AAA characteristics Maximum AAA diameter (mm) Neck length % Short neck (10-15 mm) Neck diameter (mm) Iliac diameter (mm) % With associated iliac aneurysm
Total n ¼ 218
Group A n ¼ 98 (no extenders)
Group B n ¼120 (extenders used)
p (<0.05)
218 73.9 6.9%
98 (45%) 72.7 9.2%
120 (55%) 75.0 5.2%
e NS NS
54.6% 16.5% 72.9% 22.5% 17.4% 11.5%
54.1% 19.4% 77.6% 21.4% 19.4% 13.3%
55.0% 14.2% 69.2% 23.3% 15.8% 10.0%
NS NS NS NS NS NS
58.5 24.1 10.6% 23.4 19.4 24.8%
58.0 23.6 14.3% 23.5 18.3 21.4%
59.0 24.6 7.5% 23.3 20.6 27.5%
NS NS NS NS NS NS
No significant difference between group A (patients who did not have extensions) and group B (patients that did require extensions) in terms of demographics, comorbidities, or preoperative AAA characteristics. AAA, abdominal aortic aneurysm; CAD, coronary artery disease; CRI, chronic renal insufficiency; HTN, hypertension; COPD, chronic obstructive pulmonary disease; DM, diabetes mellitus; CHF, congestive heart failure.
Table III. Intraoperative and postoperative course Parameter
Total n ¼ 218
Intraoperative and postoperative course Estimated blood loss (mL) 358 Fluoroscopy time (minute) 27.0 IV contrast (mL) 118 Length of stay (days) 5.4 30-day mortality 1.4% Complications Cardiovascular 4.6% Wound 11.9% Renal 5% Midterm outcomes Migration >10 mm 2.3% Any endoleak (all types) 41.7% % Type I endoleak 5.5% % Reinterventions 16.5% Sac regression (mm) 5.1 Follow-up time (months) 23.9
Group A n ¼ 98 (no extenders)
Group B n ¼120 (extender used)
p (<0.05)
301 27.9 115 5.1 2%
383 26.5 121 5.7 0.8%
0.03 NS NS NS NS
5.1% 10.2% 4.1%
4.2% 13.4% 5.8%
NS NS NS
1% 38.8% 5.1% 19.4% 6.1 24.8
3.3% 44.2% 5.8% 14.2% 4.4 22.7
NS NS NS NS NS NS
No significant difference between group A (patients who did not have extensions) and group B (patients who did require extensions), except for a small, but significant, difference in estimated blood loss.
standard number of components placed. When extensions were used, the device-associated cost of the procedure was significantly higher by approximately 30%. Modular two-component EVAR systems more often required extensions than three-component systems (71% vs. 27%), but the cost between these two types of device
systems in aggregate was not significantly different. The least costly solution when it occurred was a two-piece system without extensions, although the planned three-piece system did consistently provide the highest likelihood of lower costs because of lack of need for extensions, and therefore, suggests potential manufacturer-specific
90 Chandra et al.
Fig. 1. Total mean device costs. Total mean devices costs in group B (patients who received extensions) were significantly more than those in group A (patients who did not receive extensions). In patients who were in group A, total mean devices costs were significantly
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higher in those patients who received three-piece modular devices as opposed to two-piece modular devices. This difference between two- and three-piece device costs is not seen in group B patients.
Table IV. Comparison of two- and three-piece endograft systems in group B (patients who required extensions) Group B (extenders used)
Two-piece devices
Three-piece devices
p (<0.05)
Number of patients Number of proximal extenders Number of distal extenders Total number of extenders Total device cost Cost of extenders per case (percent of total cost)
99 5 160 165 $17,125 $5,712 (33%)
21 9 13 22 $16,866 $2,662 (11%)
e 0.0001 0.0001 e NS <0.0001
Significantly more proximal extenders used in the patients who received three-piece devices, although overall not many proximal devices were used. Significantly more distal extenders were used in the patients who received two-piece devices. In terms of the total mean device cost, there is no significant difference between two- and three-piece modular systems; however, the average cost of extenders per case in three-piece device systems is only $2,662, which is significantly less than the $5,712 of two-piece systems.
advantages of certain devices over others when considering device costs. The focus on rising health care costs has not escaped the vascular surgery literature, with the number of publications in PubMed on cost for vascular surgical procedures quadrupling since 1990.10 With EVAR being one of the most wellaccepted procedures done by our specialty, many studies have compared EVAR versus open repair in terms of costs. Despite clinical advantages of EVAR, including lower perioperative mortality and
length of stay, the reliance for follow-up imaging and device-related costs drive up the total cost of repair when comparing EVAR with open repair. Feezor et al.11 reported on the University of Florida experience, which mirrors our findings. The highest number of extensions used was with the AneuRx device (two-piece system), and the fewest number of extensions with the Zenith device (three-piece system), offsetting the initial cost advantage of the AneuRx endograft system. They concluded that although there was no manufacturer-specific
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Extension piece utilization during EVAR 91
Table V. Comparison of different device manufacturers Parameter
AneuRx n ¼ 61
Excluder n ¼ 78
Zenith n ¼ 79
% Needing extenders Number of extensions per case % Requiring one extension % Requiring two extensions % Requiring three extensions % Requiring four or more extensions Total costs of extensions Total device costs
84% 1.6 32% 38% 10% 4% $5,036 $15,736
58% 0.8 37% 18% 2% 1% $3,310 $15,477
25% 0.3 22% 3% 0 0 $707 $14,912
advantage in their cohort, device costs could be minimized with careful planning and choosing proper devices for patients’ anatomy. We believe that minimizing costs without compromising long-term patient outcomes is an ideal solution and should be attempted when feasible. For EVAR, that translates into using the fewest components possible without compromising aneurysm exclusion, and therefore, will be anatomy dependent. In another study of thoracic endografting, it was also confirmed that the number of device components implanted accounted for the majority (nearly 75%) of the overall cost of TEVAR.3 Using data from a multicenter trial that was used to obtain initial approval for EVAR, Sternbergh and Money5 found inpatient costs of EVAR were nearly $20,000, as compared with $12,500 for open repair. This did not even account for the postoperative follow-up necessary for EVAR, particularly with regard to costly computed tomography angiography. A multicenter review of EVAR by Bertges et al.2 in the early 2000s found that hospital costs often exceeded the diagnosis-related group for routine aneurysm repair, suggesting EVAR might even be a losing proposition in many hospitals. We all understand, however, that costs and reimbursement are often two separate entities, and can depend on a lot of local factors, including contracts, state politics, and manufacturer issues. Still, the recurrent theme in most cost analysis literature for EVAR is that more than 50% of the ‘‘cost’’ of EVAR is from the device. We therefore suggest that strategies to minimize the likelihood of the need for unplanned or unnecessary extension pieces are a surgeon-controllable factor, and this was the impetus for us to carry out this analysis in our own practice. When looking at our institutional use of extension pieces by individual manufactured device, we discovered when certain device manufacturers were used, namely AneuRx devices, that extensions
were needed 84% of the time. This was in comparison with 58% for Excluder devices and only 25% when Zenith devices were used. Acknowledging that rising costs and the need to be more efficient was important, we have since altered our practice by trying to match anatomy to certain two- versus three-stent endograft systems. Therefore, when preoperative planning suggests that a two-piece system will require bilateral distal extensions (e.g., when an extension is needed to cover the entire length of the common iliac up to the bifurcation), then we prefer to use a three-piece modular stentgraft system. On the flip side, if a two-piece system without extenders is feasible, given a patient’s anatomy, that is still considered the most costeffective. Exact reasons why extensions were used in each case are difficult to determine in this retrospective review of cases. Further clarification in terms of the reasoning or indications for extension piece use could help in terms of cost containment and adjusting practices to minimize the use of excessive or unnecessary devices. Discussions have also begun within our group with the device manufacturers to provide per-case pricing rather than per-piece pricing as another strategy to control overall costs of EVAR. Careful attention to these issues can potentially help keep the financial viability of our EVAR program, particularly with the increasing concerns about rising health care costs. Our study has several limitations. First, we focused only on device costs, which assess only one element of total EVAR costs. This neglects the many other aspects, including inpatient charges, intensive care unit stays, operating room costs, and follow-up costs. Also, our analysis of device costs is estimated based on list prices determined at the time of this study. It is possible that this determination could be over- or underestimating actual device costs, although likely balances out both groups equally. In addition, given the fact that the
92 Chandra et al.
preoperative planning and the intraoperative decision making was at the discretion of the staff surgeon, we do not have preoperative sizing sheets available for our analysis. Thus, it is challenging to clarify the exact amount of impact surgeon preference and experience led to the variability seen in these reported results, and also to determine exactly what percentage of extensions was planned versus determined intraoperatively. Again, we think these limitations should equally affect both groups, and wished to analyze our ‘‘real world’’ ability to control costs from a device standpoint. Finally, cost analysis at a single institution is not necessarily universally applicable, and we suggest other groups perform similar analyses to understand what their EVAR practice is costing in terms of device choices and extension piece utilization.
CONCLUSIONS Fifty-five percent of EVAR cases in our institution required the use of extension pieces, which resulted in an approximately 30% increase in total device costs. Although the main focus during EVAR should be the best clinical outcome with appropriate and adequate exclusion of the entire aneurysm, efforts and strategies to be cost-efficient can be effectively implemented. Given the high price of endograft components, each additional device extension is associated with an increase in total cost; this could potentially be minimized by better preoperative planning, and possibly by manufacturer-specific selection. In addition, negotiations with vendors could be considered to include alternatives in
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consignment and purchasing programs, including per-case pricing instead of per-piece pricing. REFERENCES 1. Bodenheimer T. High and rising health care costs. Part 2: technologic innovation. Ann Intern Med 2005;142:932-937. 2. Bertges DJ, Zwolak RM, Deaton DH, et al. Current hospital costs and Medicare reimbursement for endovascular abdominal aortic aneurysm repair. J Vasc Surg 2003;37:272-279. 3. Walker KL, Lipori P, Lee WA, et al. Cost of thoracic endovascular aortic repair versus open repair and implications for the US health care system. J Thorac Cardiovasc Surg 2010;139:231-232. 4. Patel ST, Haser PB, Bush HL, et al. The cost-effectiveness of endovascular repair versus open surgical repair of abdominal aortic aneurysms: a decision analysis model. J Vasc Surg 1999;29:958-972. 5. Sternbergh WC, Money SR. Hospital cost of endovascular versus open repair of abdominal aortic aneurysms: a multicenter study. J Vasc Surg 2000;31:237-244. 6. Clair DG, Gray B, O’hara PJ, et al. An evaluation of the costs to health care institutions of endovascular aortic aneurysm repair. J Vasc Surg 2000;32:148-152. 7. Paraskevas KI, Bessias N, Giannoukas AD, Mikhailidis DP. Endovascular abdominal aortic aneurysm repair (EVAR) procedures: counterbalancing the benefits with the costs. Vasc Endovascular Surg 2010;44:319-320. 8. Kim JK, Tonnessen BH, Noll RE, et al. Reimbursement of long-term post placement costs after endovascular abdominal aortic aneurysm repair. J Vasc Surg 2008;48:1390-1395. 9. Angle N, Dorafshar AH, Moore WS, et al. Open versus endovascular repair of abdominal aortic aneurysms: what does each really cost? Ann Vasc Surg 2004;18:612-618. 10. Mani K, Lundkvist J, Holmberg L, et al. Challenges in analysis and interpretation of cost data in vascular surgery. J Vasc Surg 2010;51:148-154. 11. Feezor RJ, Huber TS, Berceli SA, Nelson PR, Seeger JM, Lee WA. Impact of endograft design and product line on the device cost of endovascular aneurysm repair. J Vasc Surg 2008;47:499-503.