Cost consequence analysis of use of a balloon expandable vascular access system and standard vascular sheath for transcatheter aortic valve implantation

Abstract

Background: Vascular complications are an important complication of transcatheter aortic valve implantation and are associated with increased morbidity and mortality as well as cost. The Solopath device is an expandable vascular access system that has previously been shown to be associated with lower rates of vascular complications. This study sought to evaluate the impact of the use of this system on vascular complications and costs in a decision model analysis.

Methods: A cost-consequence analysis was undertaken utilizing event rate data from the PARTNER trials and a published retrospective analysis of the Solopath device. The decision model estimated costs and benefits in a hypothetical cohort of patients with aortic stenosis undergoing TAVI using either a standard sheath or Solopath. The modeled analysis compared the occurrence of vascular complications and mortality at 30 days and 1 year using TreeAge Pro.

Results: The decision model demonstrated that use of the Solopath sheath resulted in 36 fewer major vascular complications, three fewer deaths at 30 days, and five fewer deaths at 1 year, resulting in a discounted cost savings of $846 CDN. Results were sensitive to decreasing rates of vascular complications with newer generation devices, however maintained modest cost-savings.

Conclusions: Reduction in vascular complications is an important part of improving care for TAVI patients. The Solopath vascular access device offers an alternative to standard sheaths with a potential reduction in complications and cost-savings.

Keywords:

• Vascular complications
• bleeding
• transcatheter aortic valve implantation
• healthcare costs

JEL classification codes:

• I10
• I39

Introduction

Transcatheter aortic valve implantation (TAVI) is the treatment of choice for high-risk or inoperable patients with severe aortic stenosis¹. Despite superior results compared to medical therapy and surgical intervention, the procedure has been plagued by vascular complications. The earliest iterations of the device were between 18–24 Fr in size and required femoral vascular access of at least 7 mm, but resulted in rates of vascular complications of between 5–17%^2,3. Vascular complications have been shown to result in increased morbidity and mortality. An analysis of the PARTNER RCT demonstrated that the occurrence of major vascular complications resulted in increased mortality at both 30 days and 1 year following the TAVI procedure, as well as an increased rate of blood transfusions⁴.

The Solopath sheath is a vascular access device designed to navigate tortuous anatomy and reduce the likelihood of vascular complications by permitting insertion in a 12Fr and then expanding via balloon dilatation to a 19Fr. Retrospective analysis of patients undergoing TAVI treated with the Solopath device demonstrated both safety and effectiveness with low rates of both major vascular complications and bleeding complications⁵. The device is sold separately and adds a further cost to the procedure; however, it is a relatively small price compared to the TAVI platform costs. We sought to evaluate whether use of this device could be associated with cost-savings by reducing the number of vascular complications.

Methods

Balloon expandable vascular access system (Solopath)

The 19Fr SoloPath Transfemoral Introducer (STFI) is a vascular access device that permits large bore access with technology that enables entry into the femoral artery at a low insertion profile (12 Fr) and then radially expands to a larger profile (19 Fr), as shown in Figure 1. The STFI sheath is inserted in a folded state over an expansion balloon dilator. Once in place, the dilator is inflated which expands the sheath. When the expansion balloon dilator is removed, the introducer remains at its fully expanded 19Fr I.D. After use, the sheath is removed in the same fashion as a traditional sheath. The device enables placement of a large bore vascular sheath in the setting of tortuous anatomy prior to transcatheter aortic valve implantation.

Figure 1. Decision model.

Figure 2. Tornado plot of one-way sensitivity analysis.

Modeling approach

The economic evaluation was performed as a cost consequence analysis of the use of the Solopath device and standard vascular sheath comparing the occurrence of vascular complications and mortality at 30 days and 1 year following transcatheter aortic valve implantation. The cost-consequence analysis provides costs associated with these outcomes. A deterministic Markov cohort model was developed, using TreeAge Pro 2009 (TreeAge Software Inc., Massachusetts, USA) from the perspective of the Canadian healthcare system. The Markov cycle length was 1 year to capture clinically relevant outcomes related to the TAVI procedure.

Model overview: data and assumptions

The patient population represented in the decision model consists of a microsimulation of 1,000 hypothetical patients who have undergone a percutaneous TAVI implantation. In the first month of the model, at time zero, patients in the model have had their TAVI procedure. One treatment arm represents patients in whom a balloon-expandable vascular access system was utilized, while the other arm consists of patients managed with a standard sheath, represented by the Edwards standard sheath system. Patients in the decision model may or may not experience a vascular complication, in which case they have a risk of death or may survive to follow up at 30 days. Following the initial 30 days post-intervention, patients have an ongoing risk of death to the 1-year follow-up which is affected by their previous history of a vascular complication peri-procedure. The decision model is detailed in Figure 1.

Model data inputs

Clinical data on the rates of vascular complications occurring after TAVI were obtained from a retrospective review of patients treated with the Solopath device at our institution⁵, and are detailed in Table 1. The event data for the standard vascular sheath were obtained via structured searches using MEDLINE and systematic review of the identified sources. Most of the event data was taken from the PARTNER randomized controlled trials of TAVI⁴. Event rates were converted into probabilities following the first 30 days post-intervention. Rates of 30 day and 1 year mortality in the setting or absence of vascular complications were taken from the PARTNER trial and applied to both cohorts. Data on length of stay was obtained from the cohort of patients treated with Solopath at our institution⁵ and applied to both cohorts.

Table 1. Essential model data.

Variable	Model input	Reference/comments
Rate of major vascular complications (standard sheath, 23F)	8.2%	Généreux et al. JACC 2012^4
Rate of major vascular complications (Solopath)	4.4%	Millán et al. CCI 2016^5
30 day mortality (vascular complication)	14.1%	Généreux et al. JACC 2012^4
30 day mortality (no vascular complication)	3.1%	Généreux et al. JACC 2012^4
1 year mortality (vascular complication)	39.4%	Genereux et al. JACC 2012^4
1 year mortality (no vascular complication)	22.8%	Généreux et al. JACC 2012^4
Rate of transfusions (vascular complication)	40.7%	Généreux et al. JACC 2012^4
Rate of transfusions (no vascular complication)	5.4%	Généreux et al. JACC 2012^4
Hospital length of stay (vascular complications)	11 days	Millán et al. CCI 2016^5
Hospital length of stay (no vascular complications)	8.8 days	Millán et al. CCI 2016^5
Cost Standard sheath	0 ($CDN)	MHI billing
Cost Solopath sheath	1,000 ($CDN)	MHI billing
Cost diagnosis vascular complication	350 ($CDN)	MHI billing
Cost annual follow up	186 ($CDN)	MHI billing
Cost Blood transfusion (unit/transfused)	535 ($CDN)	OCCI initiative
Cost peripheral intervention	9,608 ($CDN)	RAMQ billing
Cost TAVI admission (no vascular complication)	31,680 ($CDN)	MHI billing
Cost TAVI admission (vascular complication)	39,600 ($CDN)	MHI billing
Discount rate	5%

Abbreviations. MHI Billing, Montreal Heart Institute billing data; OCCI, Ontario Case Costing Initiative; RAMQ billing, Regie Assurance Medicale du Quebec billing data.

Cost data were obtained from resource utilization and costs collected for the Solopath cohort. Costs were calculated using the most important cost drivers from clinical data, including diagnostic evaluation costs directly incurred as a result of vascular complications, procedural costs, and inpatient treatment costs at a large tertiary care hospital in Montreal (Montreal Heart Institute) in 2016, and were not adjusted for inflation. Follow-up costs included clinical visits and tests. These costs were applied equally to both cohorts, assuming that the costs of vascular complications, interventions required, and follow-up would be similar, regardless of the sheath used, and are expressed in Canadian dollars. Discounting was performed at 5%, as per the most recent CADTH guidelines.

Analysis

The base case analysis was performed using data from the PARTNER trials, which were the first to establish the connection between vascular complications and increased mortality. As previously mentioned, this mortality data was applied to both cohorts with the assumption that the occurrence of a vascular complication, regardless of the sheath used, would result in similar rates of 30 day and 1 year mortality. Given the evolution of devices for TAVI in the past 3 years, with lower profile and decreasing risk of vascular complications, one-way sensitivity analyses were performed using contemporary rates of vascular complications obtained from the literature^6–8. Data from studies of the Medtronic CoreValve or St. Jude Portico device were excluded from the analysis, given that many of these procedures use the Solopath sheath, therefore making any comparison difficult. Event rates were held constant for this analysis assuming constant mortality rates in the setting of vascular complications.

Results

The results of the 1-year analysis of event rates are presented in Table 2. In a hypothetical cohort of 1,000 patients, use of the Solopath sheath resulted in 36 fewer major vascular complications, three fewer deaths at 30 days, and five fewer deaths at 1 year. As a result of these lower event rates, use of the Solopath sheath for TAVI resulted in an undiscounted cost-saving of $937 CDN and a discounted cost-saving of $846 CDN, as shown in Table 3. Our model reflects what has been recently confirmed in an analysis of patients treated with large-bore vascular access devices; vascular complications are costly for the healthcare system, therefore the avoidance of vascular complications may likely result in cost-savings.

Table 2. Expected number of events at the time of the procedure (30 days) and at 12 months.

	Number of events per 1,000 patients
	Solopath	Standard sheath	Difference % (n)
At 30 days
Death	35	38	–7.8 (3)
Vascular complications	43	79	–46 (36)
Transfusions	66	52	+28 (6)
At 12 months
Death	209	214	–2.3 (5)

Table 3. Cost results.

Average per patient	Solopath	Standard sheath	Incremental difference
Undiscounted costs ($CDN)
Procedure	$956.95	$0.00	$956.95
Vascular complications	$2,133.28	$3,901.60	–$1,768.33
Transfusions	$8.65	$14.08	–$5.43
Follow-up	$147.10	$267.73	–$120.63
Total	$3,245.98	$4,183.42	–$937.43
Discounted costs ($CDN)
Procedure	$952.38	$0.00	$952.38
Vascular complications	$2,031.69	$3,715.81	–$1,684.12
Transfusions	$8.24	$13.41	–$5.17
Follow-up	$140.10	$249.03	–$108.93
Total	$3,132.41	$3,978.25	–$845.84

One-way sensitivity analysis was performed to evaluate the impact of varying rates of vascular complications given the most recent iterations of TAVI devices with smaller vessel requirements for vascular access, as shown in Figure 2. The model was sensitive to changes in the rates of vascular complications; the lower rates of major vascular complications published in the Sapien 3 and PARTNER 2 experience resulted in decreased, albeit maintained cost-savings of the Solopath sheath. This illustrates that, although new technology is reducing vascular complications, there is still a constant number of complications with important effects on morbidity, mortality, and cost. A reduction in the price of the Solopath sheath ($500 vs $1,000 CDN) resulted in increased savings compared to the standard sheath.

Discussion

Vascular complications are an important consequence of TAVI procedures, and contribute significantly to increased morbidity and mortality as well as cost. This decision analysis demonstrates that use of the Solopath device, which is associated with a lower rate of vascular complications, results in important cost-savings, despite its additional cost.

The impact of vascular complications on cost of the TAVI procedure has been previously documented. An analysis by Arnold et al.⁹, based on the PARTNER trial cohort, identified peri-procedural complications as an important cost driver for TAVI. Specifically, major bleeding resulted in increased length of stay and was the most important driver of increased costs, accounting for $3,990 per patient of the total hospitalization cost. An analysis of the Healthcare Cost and Utilization Project’s National Inpatient Sample (NIS) database of patients undergoing transcatheter procedures utilizing large bore vascular access between 2012–2013, namely TAVI, endovascular aortic repair (EVAR), and percutaneous left ventricular assist devices (pLVAD) had similar findings. Vascular complications were common, occurring in 30% of patients with TAVI, and were associated with a 2-fold increase in death, prolonged hospitalization, and higher healthcare cost. In addition, the risks of these events increased further as the number of blood transfusions increased¹⁰. This resulted in an average increase in cost of over $17,000 USD for those patients with bleeding complications compared to those without.

Since this early experience, more recent iterations of TAVI devices are smaller (14–16 Fr), with vascular access requirements of only 5.5–6.5 cm. This has resulted in a reduction of vascular complications, as demonstrated by rates of major vascular complications of 6.1% in the Sapien 3 study¹¹ and 6.0% in the SURTAVI Intermediate risk TAVI study¹². These scenarios were evaluated in one-way sensitivity analysis and showed persistent cost-savings of the Solopath sheath.

Study limitations

This study utilizes a decision model to perform an economic evaluation of the use of the Solopath device for transcatheter aortic valve implantation. The model utilizes data inputs from the published literature for both the Solopath and standard sheath. The standard sheath was assumed to be that used for TAVI procedures with the Edwards transcatheter aortic valves. This analysis is limited by the comparison with the early generation Edwards system which was associated with larger vascular access. Sensitivity analysis was completed to evaluate the comparison between Solopath and more contemporary data with the newer and smaller device systems. Data from the literature utilizing other valves, namely the Medtronic CoreValve or St. Jude Portico, were not included, since a significant proportion of these procedures are actually performed using the Solopath device. The study is limited in that it follows a hypothetical cohort of 1,000 patients for 1 year only and may be an over-simplification of clinical practice and the costs related to such procedures; however, it does inform on the potential consequences and costs of vascular complications and the potential benefits of avoiding this with additional devices. In addition, the association between vascular complications and death was based on one analysis of the PARTNER data and, therefore, may not accurately reflect current mortality rates with the most modern technology.

Conclusions

Vascular complications and major bleeding are important consequences of TAVI procedures that result in increased mortality and cost to the healthcare system. In this modeled analysis, use of a novel vascular access system was associated with a reduction in major vascular complications and important cost-savings.

Transparency

Declaration of funding

This work was supported by Terumo Corporation.

Declaration of financial/other relationships

AA is a consultant for Terumo, Medtronic, and Edwards LifeSciences. RI is a consultant for Edwards LifeSciences. RB is a consultant for Medtronic. The remaining authors have no relevant disclosures. JME peer reviewers on this manuscript have no relevant financial or other relationships to disclose.

Acknowledgments

None reported.

Additional information

Funding

Novo Nordisk A/S;