Abstract
Aims: Transcatheter aortic valve implantation (TAVI) is an alternative to surgical valve replacement for patients with aortic stenosis (AS). This study assessed the impact of changing from a self-expandable (SE) valve to a balloon-expandable (BE) valve on healthcare resource use and procedural costs in a population of inoperable AS patients.
Methods: In this retrospective single center study, data for 195 patients who received either an SE or a BE valve between 2010–2014 were collected. Procedural and post-procedural healthcare resource use and cost parameters were determined for the two groups.
Results: The study showed that overall procedural time, including time required by medical personnel, was significantly shorter for TAVI using a BE compared with an SE valve. Post-surgery, patients in the BE valve group had significantly shorter hospital stays than the SE valve group, including significantly fewer days spent in the intensive care unit (ICU). Additionally, trends towards reduced 30-day mortality, incidence of new permanent pacemaker implantation, and incidence of blood transfusion were observed in the BE valve group compared with the SE valve group. Finally, total procedural costs were 24% higher in the SE compared with the BE valve group.
Limitations: The BE valve data were acquired in a single year, whereas the SE valve data were from a 5-year period. However, a year-by-year analysis of patient characteristics and study outcomes for the SE valve group showed few significant differences over this 5-year period.
Conclusions: Overall, changing from an SE to a BE valve for TAVI in patients with severe AS reduced both healthcare resource use and procedure-related costs, while maintaining patient safety. For healthcare providers, this could increase efficiency and capacity within the healthcare system, with the added advantage of reducing costs.
Introduction
Aortic stenosis (AS) is a narrowing of the aortic valve, most commonly caused by age-related calcificationCitation1. The standard of care for severe AS is surgical aortic valve replacement (SAVR)Citation2,Citation3. A minimally invasive alternative is transcatheter aortic valve implantation (TAVI), where a bioprosthetic valve is delivered through an artery, usually transfemorally (TF-TAVI), to displace the diseased valveCitation4–7.
The two most widely used TAVI devices are the balloon-expandable (BE) valves, e.g. Edwards Lifesciences SAPIEN valves, and the self-expandable (SE) valves, e.g. Medtronic Inc CoreValvesCitation8,Citation9. In inoperable patients, both types of valve significantly reduced rates of all-cause mortality and improved New York Heart Association functional class (NYHA FC) III/IV symptoms compared with standard treatmentCitation4,Citation7. In high and intermediate risk patients, both types of valve were shown to be either comparable or superior to SAVR in terms of their efficacy and safetyCitation10–16. Although both the BE and SE valves are reported to have excellent flow characteristicsCitation4,Citation6,Citation7,Citation10,Citation12,Citation15–17, differences in their technologies may impact on procedural ease and device success. This is supported by the randomized head-to-head CHOICE trial, which demonstrated that a BE valve was associated with a greater rate of device success (a composite end-point measuring acute procedural success) and lower prevalence of TAVI-associated complications, compared with an SE valveCitation9,Citation18. A recent study has also shown that TF-TAVI with the new generation SAPIEN 3 valve is superior to the CoreValve (an SE valve) in terms of rates of paravalvular leakage, new permanent pacemaker implantation, and device successCitation19.
AS is the most prevalent valvular disease in the developed world, and severe AS affects 3.4% of the elderly population (≥75 years)Citation20. In today’s ageing societies, the incidence of severe AS is expected to double by 2050 in the US and EuropeCitation20. Thus, the need for TAVI will continue to riseCitation21, leading to an increasing demand on healthcare resources. A number of studies have demonstrated that TAVI is highly likely to be cost-effective and to improve health-related quality-of-life compared with medical management or SAVRCitation22–27. Nevertheless, there remains a clear need to ensure that TAVI procedures can be performed as efficiently as possible in order to minimize the burden on healthcare providers without compromising patient outcomesCitation28.
This study assessed whether, for inoperable patients with severe AS, healthcare resource use and procedural costs associated with TAVI could be reduced by changing from an SE valve to a BE valve.
Methods
Patient population
This was a retrospective, single-center cohort study performed at the University Heart Centre Freiburg, Bad Krozingen, Germany. Data were collected from hospital records with approval from an internal committee at the hospital. All consecutive patients who received either a BE valve (Edwards SAPIEN 3) or an SE valve (Medtronic CoreValve) via TF TAVI between 2010–2014 were included. All procedures were elective and performed under general anesthesia. In the BE valve group, 23 mm, 26 mm, and 29 mm valves were implanted and, in the SE valve group, 23 mm, 26 mm, 29 mm, and 31 mm valves were used.
Outcome measures
Procedural parameters were defined as operating room type (hybrid room or catheterization laboratory), total procedural time, number of personnel present, cumulative personnel time, fluoroscopy time, and volume of contrast media used. Post-procedural parameters included death up to 30 days, vascular complications, intensive care unit (ICU) length of stay (LoS), post-operative ward LoS, total LoS and requirement for new pacemaker implantation, dialysis, or blood transfusion. Costs were determined according to the guidelines of the Institut für das Entgeltsystem im Krankenhaus (InEK), and included the costs of all in-hospital complications experienced by the patients.
Statistical analyses
Statistical analyses were performed using R version 2.5.13Citation29. Categorical data were presented as frequencies and were compared with the Pearson χ2 test. Continuous variables are expressed as the mean ± standard deviation and were compared by use of the t-test or analysis of variance as appropriate. A p-value <.05 was considered to indicate statistical significance. Differences in costs between valves were presented as percentages.
Results
Patient characteristics
A total of 195 patients underwent TF TAVI between 2010–2014. One hundred patients received a BE valve, and 95 received an SE valve. All BE valves were implanted in 2014, whereas the SE valves were implanted between 2010–2014. The overall study population were elderly (mean age = 83.0 years) and had significant comorbidities, including chronic obstructive pulmonary disease, diabetes, and severe angina (). The two groups were generally well balanced in terms of baseline characteristics. The only statistically significant differences were a higher BMI in the BE valve arm compared with the SE valve arm (27.5 ± 5.9 vs 25.3 ± 3.87, p = .002), and more patients in the SE valve arm had previous aortic bioprosthetic valve replacement (0% vs 6.3%, p = .011).
Table 1. Baseline characteristics—BE vs SE valve groups.
Procedural resource utilization
All SE valve implantations between 2010–2013 were performed in a catheterization laboratory (). In 2014, all TAVI procedures were performed in a hybrid operating room, with the exception of one SE valve implantation, which was carried out in a catheterization laboratory. Overall, the total procedure was significantly shorter in duration for the BE valve group compared with the SE valve group (88.4 ± 39.7 min vs 115 ± 42.9 min, p < .001). Furthermore, the mean cumulative time spent by personnel per procedure was significantly shorter for the BE valve group compared with the SE valve group (physicians: 273 ± 146 min vs 360 ± 188 min, p < .001; nurses: 243 ± 121 min vs 312 ± 164 min, p = .001) (), although the number of personnel required per procedure did not differ. Furthermore, the mean fluoroscopy time per procedure was shorter in the BE valve group compared with the SE valve group (15.5 ± 8.74 min vs 19.4 ± 11.2 min, p = .008) (). For the BE valve group, 23 mm (44%), 26 mm (44%), and 29 mm (12%) valves were implanted and, in the SE valve group, implanted device sizes were 23 mm (5.3%), 26 mm (23.2%), 29 mm (58.9%), and 31 mm (12.6%).
Table 2. Procedural parameters—BE vs SE valve groups.
Post-operative outcomes and resource utilization
There were no statistically significant differences in post-operative clinical outcomes. However, clinically-relevant trends towards reduced 30-day mortality (5.4% reduction), incidence of new permanent pacemaker implantation (10.6% reduction), and incidence of blood transfusion (10.8% reduction) were observed in the BE valve group compared with the SE valve group. Conversely, a trend of higher rate of vascular complications was reported for the BE valve patients compared with the SE valve patients (4.3% increase) (). For patients who required a new permanent pacemaker, the duration of the pacemaker implantation procedure was significantly shorter in the BE valve group compared with the SE valve group (85.9 ± 24.06 min vs 98.74 ± 26.99 min, p = .041). In comparison to the SE valve group, patients in the BE valve group required significantly shorter total hospital stays (8.69 ± 3.81 days vs 11.11 ± 5.53 days, p = .001). Patients receiving a BE valve also required fewer days in the ICU compared to those receiving an SE valve (2.51 ± 2.04 days vs 3.56 ± 2.86 days, p = .004). An additional analysis demonstrated that all patients receiving a new permanent pacemaker had a significantly longer total (11.07 ± 5.13 days vs 9.23 ± 4.68 days, p = .016) and ICU (3.6 ± 2.84 days vs 2.76 ± 2.33 days, p = .04) length of stay compared with those who did not receive a new pacemaker (Supplementary Table 1).
Table 3. Post-procedural parameters—BE vs SE valve groups.
Costs
The costs of personnel, operating room, and ICU care were all significantly lower in the BE valve group compared with the SE valve group (). In total, procedural costs were 24% higher with the SE valve compared with the BE valve, mainly driven by the longer personnel time and longer ICU LoS.
Table 4. Costs BE vs SE valve groups.
Discussion
There are two main types of TAVI valve currently being used in clinical practice. These valves utilize different technologies and require different implantation procedures. This study aimed to determine the impact of changing from an SE valve to a BE valve on the healthcare resource use and costs associated with the TAVI procedure.
Overall procedural time, including time spent by medical personnel and fluoroscopy time, was significantly shorter for the BE valve group compared with the SE valve group. This suggests that the BE valve implantation procedure may be more efficient than the procedure for SE valve implantation.
Post-procedure, patients in the BE valve group spent fewer days in the ICU and their total LoS was significantly shorter compared with the SE valve group. This observation is unlikely to be due to the patients’ condition at baseline, as, apart from BMI, no significant differences between the two study arms were observed in any of the baseline characteristics. This includes the EuroSCORE, which has previously been shown to be an independent predictor of ICU LoS after cardiac surgeryCitation30,Citation31. Instead, the reduced LoS may relate to the shorter procedural time and the trend for reduced rates of post-operative complications in the BE valve group compared with the SE valve group. In particular, a trend for reduced rates of permanent pacemaker implantation in the BE valve group compared with the SE valve group may have contributed to the reduced LoS for the patients receiving a BE valve. This is supported by the data shown in Supplementary Table 1 and a recently published registry study which demonstrated an association between permanent pacemaker implantation and longer hospital stayCitation32.
In this study, changing from an SE valve to a BE valve for TF TAVI reduced the overall procedural costs (excluding valve costs) (procedural costs were 24% higher in the SE valve group compared with the BE valve group). This was driven by significant reductions in procedural and personnel time, and significantly shorter ICU LoS. The trend for reduced post-operative complications may also have contributed to the lower procedural costs reported for the BE valve.
Reduced procedural times and post-operative LoS will benefit both patients and healthcare providers. For patients, a reduction in the time spent in surgery may lead to improved safety, e.g. by limiting time spent under general anesthesia and by reducing blood loss. Furthermore, due to the shorter fluoroscopy time required for implantation of the BE valve compared with the SE valve, exposure to X-ray radiation will also be reduced. A shorter LoS in hospital also offers clear benefits to patients and is associated with increased patient satisfactionCitation33. Furthermore, the risk of nosocomial infections is reducedCitation34. For healthcare providers, shorter procedures, reduced personnel time, and reduced hospital LoS can free up bed space and increase capacity within the system, and, all else being equal, potentially reduce waiting list time for both TAVI and other cardiovascular procedures. Reducing costs is also clearly advantageous for healthcare providers at a time of growing demand for healthcare services and ever tightening budgets.
This study has several limitations. First, this was a single-center, retrospective, non-randomized study, which can result in patient selection bias and missing data, potentially introducing bias into the results. Second, the BE valves were exclusively implanted in 2014, whereas the SE valve data are from 2010–2014. Increasing operator experience over time is, therefore, a possible explanation for the reduced procedure and personnel time observed with the BE compared with the SE valves. To address this, a year-by-year analysis of patient baseline characteristics and study outcomes was performed (Supplementary Tables 2–4). This analysis showed no trend for reduction in procedure and personnel time over the 5-year period for which data were collected, suggesting that increasing operator experience over time does not explain the increased procedural efficiency observed after changing from an SE valve to a BE valve. Of note, a significant reduction over time was recorded for the proportion of patients who were in NYHA FC III/IV at baseline, suggesting that patients may now be undergoing TAVI at an earlier stage of disease. Furthermore, a trend for reduced ICU LoS was also observed over the 5-year period (p = .0307). However, the differences in FC are unlikely to provide an explanation for the reduced ICU LoS reported for the BE valve group compared with the SE valve group, given that there was no statistically significant difference in baseline FC between the two study arms. Third, with only 195 patients over 5 years, the study center’s caseload is relatively low. The results of this study may, therefore, be less applicable to higher volume centers which may utilize different patient management processes. Finally, the BE valve used in this study is the latest device in the SAPIEN platform of valves (SAPIEN 3), whereas the latest generation SE valve was not utilized.
Conclusions
In current clinical practice, TF TAVI can be performed using either a BE valve or an SE valve. In this single-center study, changing from an SE valve to a BE valve resulted in increased procedural efficiency without compromising patient safety. Furthermore, compared to an SE valve, implantation of a BE valve to treat severe AS is likely to reduce resource use as well as procedure-related costs.
Transparency
Declaration of funding
The study was funded by Edwards Lifesciences.
Declaration of financial/other interests
HK receives sponsorship from Edwards Lifesciences. JB is an employee and stock shareholder of Edwards Lifesciences. Peer reviewers on this manuscript have received an honorarium from JME for their review work, but have no other relevant financial relationships to disclose.
Acknowledgments
Medical writing support was provided by nspm ltd, Meggen, Switzerland, and funded by Edwards Lifesciences.
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