Cost-Effectiveness of Self-Expandable Transcatheter Aortic Valves in Intermediate-Risk Patients

Transcatheter Versus Surgical Aortic Valve Replacement in Recipients of Solid Organ Transplants and Liver Cirrhosis: A Propensity-Matched Analysis of National Readmission Data

Transcatheter aortic valve replacement (TAVR) continues to grow in the United States. There are limited data on recipients of solid organ transplant (SOT) and patients with liver cirrhosis who undergo aortic valve replacement (AVR). Our study aims to evaluate outcomes in these populations. Using the national readmission database (2016 to 2020), we identified recipients of SOT and patients with liver cirrhosis without previous liver transplants who were admitted for severe aortic stenosis and underwent either TAVR or surgical AVR (SAVR). We used multivariable regression for adjusted analysis and the propensity score matching model, implementing complete Mahalanobis distance matching within the Propensity Score Caliper (0.2) to match TAVR and SAVR cohorts for outcomes. Of 3,394 hospitalizations for AVR in recipients of SOT, 2,181 underwent TAVR, and 1,213 underwent SAVR. On propensity-matched analysis, SAVR was associated with more adverse events than was TAVR, including in-hospital mortality (5.2% vs 1.1%, adjusted odds ratio [aOR] 4.49, p <0.001), acute kidney injury (43.7% vs 10.2%, p <0.001), cardiogenic shock (9.0% vs 1.6%, p <0.001), sudden cardiac arrest (15.9 vs 6.0%, p <0.001), major adverse cardiac and cerebrovascular events (28% vs 10.4%, p <0.001), and net adverse events (72.8 vs 37.6%, p <0.001). A greater median length of stay (10 vs 2 days, p <0.001) and adjusted cost ($80,842 vs $57,014, p <0.001) were also observed. The readmission rates were the same for both cohorts after a 6-month follow-up. Similarly, in 14,763 hospitalizations for AVR in liver cirrhosis, 7,109 patients underwent TAVR, and 7,654 underwent SAVR. In propensity-matched cohorts (n = 2,341), SAVR was found to be associated with greater adverse events, including in-hospital mortality (19.8% vs 10%), stroke (6.7% vs 2%), acute kidney injury (67.7% vs 30.3%), cardiogenic shock (41.9% vs 19.9%), sudden cardiac arrest (31.8% vs 13.2%, aOR 2.89), major adverse cardiac and cerebrovascular events (66.2% vs 35.7%), and net adverse events (86% vs 59.5%) (p <0.001). A greater median length of stay (16 vs 3 days) and cost ($500,218 vs $263,383) were also observed (p <0.001). However, the rate of readmissions at 30-day (9% vs 11.1%) and 180-day intervals (33.4% vs 39.8%) was lower for the SAVR cohort (p <0.05). In recipients of SOT and patients with liver cirrhosis, SAVR is associated with greater short-term mortality, adverse events, and healthcare burden than is TAVR. TAVR is a relatively safer alternative to SAVR in these patient populations, although further studies are warranted to compare the long-term outcomes.

Impact of cerebral protection on observed versus predicted in-hospital stroke in a high stroke risk TAVR cohort

BACKGROUND

Despite impressive improvements in the safety profile of Transcatheter aortic valve replacement (TAVR), the risk for peri-procedural stroke after TAVR has not declined substantially. In an effort to reduce periprocedural stroke, cerebral embolic protection (CEP) devices have been utilized but have yet to demonstrate benefit in all-comers. There is a paucity of data supporting the utilization of CEP in TAVR patients with an anticipated high risk for peri-procedural stroke.

METHODS

The Transcatheter Aortic Valve Replacement In-Hospital Stroke (TASK) score is a clinical risk tool for predicting the in-hospital stroke risk of patients undergoing transfemoral TAVR. This score was used to identify high-risk patients and calculate the expected in-hospital stroke risk. This was a single-centre cohort study in all consecutive TAVR patients who had placement of CEP. The observed versus expected ratio for peri-procedural stroke was calculated. To obtain 95% credible intervals, we used 1000 bootstrapped samples of the original cohort sample size without replacement and recalculated the TASK predicted scores.

RESULTS

The study included 103 patients. The median age was 83 (IQR 78,89). 63 were male (61.1%) and 45 (43.69%) had a history of previous Stroke or TIA. Two patients had an in-hospital stroke after TAVR (1.94%). The expected risk of in-hospital stroke based on the TASK score was 3.39% (95% CI 3.07-3.73). The observed versus expected ratio was 0.57 (95% CI 0.52-0.64).

CONCLUSION

In this single-center study, we found that in patients undergoing TAVR with high stroke risk, CEP reduced the in-hospital stroke risk by 43% when compared with the risk-score predicted rate.

CLINICAL TRIAL NUMBER

N/A.

Decision analysis in cardiac surgery: a scoping review and methodological primer

OBJECTIVES

Randomized controlled trials are the gold standard for evidence generation in medicine but are limited by their real-world generalizability, resource needs, shorter follow-up durations and inability to be conducted for all clinical questions. Decision analysis (DA) models may simulate trials and observational studies by using existing data and evidence- and expert-informed assumptions and extend analyses over longer time horizons, different study populations and specific scenarios, helping to translate population outcomes to patient-specific clinical and economic outcomes. Here, we present a scoping review and methodological primer on DA for cardiac surgery research.

METHODS

A scoping review was performed using the PubMed/MEDLINE, EMBASE and Web of Science databases for cardiac surgery DA studies published until December 2021. Articles were summarized descriptively to quantify trends and ascertain methodological consistency.

RESULTS

A total of 184 articles were identified, among which Markov models (N = 92, 50.0%) were the most commonly used models. The most common outcomes were costs (N = 107, 58.2%), quality-adjusted life-years (N = 96, 52.2%) and incremental cost-effectiveness ratios (N = 89, 48.4%). Most (N = 165, 89.7%) articles applied sensitivity analyses, most frequently in the form of deterministic sensitivity analyses (N = 128, 69.6%). Reporting of guidelines to inform the model development and/or reporting was present in 22.3% of articles.

CONCLUSION

DA methods are increasing but remain limited and highly variable in cardiac surgery. A methodological primer is presented and may provide researchers with the foundation to start with or improve DA, as well as provide readers and reviewers with the fundamental concepts to review DA studies.

A Systematic Review and Statistical Analysis of Factors Influencing the Cost-Effectiveness of Transcatheter Aortic Valve Implantation for Symptomatic Severe Aortic Stenosis

Objective

Transcatheter aortic valve implantation (TAVI) is a disruptive technology recommended for patients with symptomatic severe aortic stenosis (sSAS). Despite being available for over 15 years in Europe, with an extensive volume of clinical and economic evaluations across all surgical risk groups, there is little evidence on the identification of the key drivers of TAVI's cost-effectiveness. This study sought to identify these factors and quantify their role.

Methods

A systematic literature review was conducted to identify published economic evaluations of TAVI. This was supplemented by health technology assessment reports. The primary outcome was the likelihood of TAVI being found cost-effective. Secondary outcomes of TAVI being dominant, and the incremental health benefits of TAVI were also explored.

Results

Forty-two studies, reporting 65 unique analyses, were identified. TAVI was found to be cost-effective and dominant in 74% and 20% of analyses, respectively. The latest generation balloon-expandable TAVI device (SAPIEN 3) was more likely to be found cost-effective, as was TAVI use in low-risk populations and when performed via transfemoral access route. There was heterogeneity in the approach taken to economic modelling, which may also influence estimates of cost-effectiveness. Analyses that found TAVI to be dominant always compared it to surgery and usually considered the latest generation balloon-expandable TAVI device. Largest health benefits were observed for the inoperable risk group.

Conclusion

For patients with sSAS, TAVI is typically a cost-effective treatment option. There are important differences by device generation, risk group and access route. It is crucial to consider these differences when appraising the health economic evidence-base for TAVI.

Estimation of Value-Based Price for 48 High-Technology Medical Devices

Value-based price is estimated quite frequently for medicines, but its application to medical devices is scarce. While some reports have been published in which this parameter has occasionally been determined for devices, no large-scale application has yet been reported. Our objective was to pursue a systematic analysis of the literature published on value-based prices of medical devices. Pertinent papers were selected upon the criterion that the value-based price was reported for the device examined. The real prices of the devices were compared with their values of value-based price and the ratios between real price versus value-based price were calculated. A total of 239 economic articles focused on high-technology medical devices were selected from a standard PubMed search. Among these, the proportion of analyses unsuitable for value-based price estimation was high (191/239; 80%), whereas adequate clinical and economic information for estimating this parameter was available in 48 cases (20%). Standard equations of cost-effectiveness were applied. The value-based price was determined according to a willingness-to-pay threshold of 60,000 € per quality-adjusted life year. Real prices of devices were compared with the corresponding estimates of value-based prices. From each analysis, we extracted also the value of incremental cost-effectiveness ratio (ICER). Our final dataset included 47 analyses because one was published twice. There were five analyses in which the ICER could be estimated for the treatment, but not for the device. In the dataset of 42 analyses with complete information, 36 out of 42 devices (86%) were found to have an ICER lower than the pre-specified threshold (favorable ICER). Three ICERs were borderline. A separate analysis was conducted on the other three devices that showed an ICER substantially greater than the threshold (unfavorable ICER). Regarding value-based prices, the values of real price were appreciably lower than the corresponding value-based price in 36 cases (86%). For three devices, the real price was substantially higher than the value-based price. In the remaining three cases, real prices and value-based prices were very similar. To our knowledge, this is the first experience in which a systematic analysis of the literature has been focused on the application of value-based pricing in the field of high-technology devices. Our results are encouraging and suggest a wider application of cost-effectiveness in this field.

Transcatheter aortic valve implantation in patients with severe symptomatic aortic valve stenosis: systematic review of cost-effectiveness analysis

BACKGROUND

Transcatheter aortic valve implantation (TAVI) is a less invasive and costly treatment for patients with severe aortic stenosis (AS). This study aimed to systematically review the published literature focusing on economic evaluation of TAVI compared with other alternative treatments in AS populations.

METHODS

A systematic review was conducted from inception until May 2021 using PubMed, Scopus, Web of science and Embase databases. The qualities of included studies were evaluated using Consolidated Health Economic Evaluation Reporting Standard (CHEERS) criteria. Data of costs, outcomes, incremental cost-effectiveness ratio (ICER) and willingness to pay were extracted. To compare results, ICERs were converted to the 2020 United States dollar (USD) rate.

RESULTS

Of the 29 included cost-effectiveness studies, TAVI was cost-effective in all studies in the low-risk group (3/3), 77% of studies (7/9) in the intermediate-risk group, half of the studies (6/12) in the high-risk group, and 83% of studies (10/12) in the inoperable group. When adjusted to USD 2020, ICERs ranged from USD 2741 to 1027,674 USD per quality-adjusted life-year gained. The overall quality of the studies ranged from moderate to high.

CONCLUSIONS

TAVI is potentially a cost-effective alternative to surgical aortic valve replacement (SAVR) for patients with operable AS with low, intermediate or high risk compared with medical management (MM) for patients with inoperable AS. TAVI was associated with a significant gain in quality-adjusted life-years in almost all studies compared to either SAVR or MM. TAVI is a costly procedure; therefore, justifying its cost-effectiveness depends on the acceptable threshold in each country.

Incorporating economic analysis in interventional cardiology research

Evaluative research in interventional cardiology has focused on clinical and technical outcomes. Inclusion of economic data can enhance evaluative research by quantifying the relative economic burden incurred by different therapies. When combined with clinical outcomes, cost data can provide a measure of value (e.g., marginal cost-effectiveness). In some select situations, cost data can also be used as surrogates for complexity of care and morbidity. In this narrative review, we aim to provide a framework for the application of cost data in clinical trials and observational research, detailing how to incorporate this kind of data into interventional cardiology research.

Cost-effectiveness of transcatheter aortic valve implantation in patients with severe symptomatic aortic stenosis of intermediate surgical risk in Singapore

Objective

The objective was to assess the cost-effectiveness of transcatheter aortic valve implantation (TAVI) in patients with severe aortic stenosis with intermediate surgical risk in Singapore.

Methods

A de novo Markov model with three health states – stroke with long-term sequelae, no stroke, and death – was developed and simulated using Monte Carlo simulations with 10,000 iterations over a five-year time horizon from the Singapore healthcare system perspective. A 3% annual discount rate for costs and outcomes and monthly cycle lengths were used. By applying the longest available published clinical evidence, simulated patients received either TAVI or surgical aortic valve replacement (SAVR) and were at risk of adverse events (AEs) such as moderate-to-severe paravalvular aortic regurgitation (PAR).

Results

When five-year PARTNER 2A data was applied, base-case analyses showed that the incremental cost-effectiveness ratio (ICER) for TAVI compared to SAVR was US$315,760 per quality-adjusted life year (QALY) gained. The high ICER was due to high incremental implantation and procedure costs of TAVI compared to SAVR, and marginal improvement of 0.10 QALYs as simulated mortality of TAVI exceeded SAVR at 3.75 years post-implantation. One-way sensitivity analysis showed that the ICERs were most sensitive to cost of PAR, utility values of SAVR patients, and cost of TAVI and SAVR implants and procedures. When disutilities for AEs were additionally applied, the ICER decreased to US$300,070 per QALY gained. TAVI was dominated by SAVR when the time horizon increased to 20 years. Clinical outcomes projected from one-year PARTNER S3i data further reduced the ICER to US$86,337 per QALY gained for TAVI, assuming early all-cause mortality benefits from TAVI continued to persist. This assumption was undermined when longer term data showed that TAVI’s early mortality benefits diminished at five years.

Limitations and conclusion

TAVI is unlikely to be cost-effective in intermediate surgical-risk patients compared to SAVR in Singapore.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12913-022-08369-5.

Economic Evaluation of Transcatheter Aortic Valve Replacement Compared to Surgical Aortic Valve Replacement in Chinese Intermediate-Risk Patients

Background

Aortic stenosis (AS) is a severe disease that causes heart failure and sudden death. Transcatheter aortic valve replacement (TAVR) and surgical aortic valve replacement (SAVR) are both recommended for patients with intermediate surgical risk, but the cost-effectiveness of TAVR compared to SAVR in China has not been investigated.

Methods

A combined decision tree and Markov model were conducted to compare the cost-effectiveness of TAVR versus SAVR with a 5-year simulation. The primary outcome was the incremental cost-effectiveness ratio (ICER), a ratio of incremental costs to incremental quality-adjusted life-year (QALY). One-way sensitive analysis and probabilistic sensitivity analysis (PSA) were conducted to test the robustness of the model.

Results

After a simulation of 5 years, the costs of TAVR and SAVR were 54,573 and 35,002 USD, respectively, and the corresponding effectiveness was 2.826 versus 2.712 QALY, respectively. The ICER for the TAVR versus SAVR comparison was 170,056 USD/QALY, which was three times higher than the per capita gross domestic product (GDP) in China. One-way sensitive analysis showed that the cost of the TAVR device impacted the ICER. The TAVR could be cost-effective only in the case where its cost is lowered to 29,766 USD.

Conclusion

TAVR is currently not cost-effective in China, but it could be cost-effective with a reduction of costs to 29,766 USD, which is approximately 65% of the current price.

The transcatheter aortic valve implantation: an assessment of the generalizability of the economic evidences following a systematic review

OBJECTIVES

Scientific literature debates on the economic affordability of transcatheter aortic valve implantation (TAVI) in order to give a useful support to decision makers aiming at establishing a reimbursement scheme for TAVI. For this reason, it is important to assess the quality and the generalizability of the existing economic evidences.

METHODS

The first step was to run a literature search according to a predefined population, intervention, comparator, and outcome on the cost and effectiveness of the TAVI procedure in comparison to medical therapy and traditional surgery. Second, a manual search was carried out on the Web sites of the main HTA agencies. Third, the checklist developed by Augustovski et al. was applied in order to assess the quality and the generalizability of the articles resulting from the selection process.

RESULTS

Overall, 106 articles were obtained. Of these, sixty-five articles were excluded since the title was not consistent with the objective. Further selection took place after abstract and full-text reading. In the end, thirty-one documents were included for the review. According to the checklist, none of the articles was considered generalizable and only one was considered transferable which compares the TAVI procedure with Medical Management in inoperable patients.

CONCLUSIONS

Despite the overall quality of the selected studies was considered good, there is still a lack of evidence on whether evidences generated in different contexts can be considered generalizable. Further research on resource consumption and preferences is needed in order to provide decision makers with more robust evidences.

Transcatheter Aortic Valve Implantation (TAVI) Versus Surgical Aortic Valve Replacement for Aortic Stenosis (SAVR): A Cost-Comparison Study

BACKGROUND

Comparative costing studies using real-world data stratified by patient case-mix, are valuable to decision makers for making reimbursement decisions of new interventions. This study evaluated real-world hospital admissions and short-term costs of transcatheter aortic valve implantation (TAVI) and isolated surgical aortic valve replacement (SAVR) for patients with aortic stenosis, stratified by the Society of Thoracic Surgeons (STS) risk scores.

METHODS

Retrospective analysis of consecutive patients with a principal diagnosis of aortic stenosis who underwent isolated valve replacement at a single tertiary hospital, January 2012-December 2017. Patients were followed-up for 30 days post-procedure or until hospital discharge if index hospitalisation was greater than 30 days. Intensive care unit (ICU) and hospital length of stay (days), and costs in 2018 Australian dollars for the index procedure and 30-day follow-up were assessed. Multivariable generalised linear and two-part models with gamma distribution and log link function adjusting for Society of Thoracic Surgeons (STS) risk group and key sociodemographic characteristics were used.

RESULTS

Of 488 patients, 61% males, median age 78 years (IQR 14 years), 221 (45%) received transcatheter aortic valve replacement (TAVI) and 267 (55%) received surgical aortic valve replacement (SAVR). STS risk scores were low (28%), intermediate (46%) and high (26%) for TAVI patients, and low (85%), intermediate (12%) and high (3%) for SAVR patients. When adjusted, TAVI length of stay was 57% shorter than SAVR (95% CI 31-83%, p<0.001) for intensive care unit (ICU) admission, and 64% shorter (95% CI 47-81%, p<0.001) for hospital admissions. TAVI costs were 13% lower than SAVR (95% CI 4-22%, p=0.005).

CONCLUSION

This data suggests short-term health care costs are lower for patients with aortic stenosis undergoing TAVI than SAVR. A further roll-out of the TAVI program in hospitals across Australia may result in savings to the health system.

The Use of Decision Analytic Modeling in the Evaluation of Surgical Innovations: A Scoping Review

OBJECTIVES

The main objective of this review was to map how decision analytic models are used in surgical innovation (in which research phase, with what aim) and to understand how challenges related to the assessment of surgical interventions are incorporated.

METHODS

We systematically searched PubMed, Embase, and the Cochrane Library for studies published in 2018. We included original articles using a decision analytic model to compare surgical strategies. We included modeling studies of surgical innovations. General, innovation, and modeling characteristics were extracted, as were outcomes, recommendations, and handling of challenges related to the assessment of surgical interventions (learning curve, incremental innovation, dynamic pricing, quality variation, organizational impact).

RESULTS

We included 46 studies. The number of studies increased with each research phase, from 4% (n = 2) in the preclinical phase to 40% (n = 20) in phase 3 studies. Eighty-one studies were excluded because they investigated established surgical procedures, indicating that modeling is predominantly applied after the innovation process. Regardless of the research stage, the aim to determine cost-effectiveness was most frequently identified (n = 40, 87%), whereas exploratory aims (eg, exploring when a strategy becomes cost-effective) were less common (n = 9, 20%). Most challenges related to the assessment of surgical interventions were rarely incorporated in models (eg, learning curve [n = 1, 2%], organizational impact [n = 2, 4%], and incremental innovation [n = 1, 2%]), except for dynamic pricing (n = 10, 22%) and quality variation (n = 6, 13%).

CONCLUSIONS

In surgical innovation, modeling is predominantly used in later research stages to assess cost-effectiveness. The exploratory use of modeling seems still largely overlooked in surgery; therefore, the opportunity to inform research and development may not be optimally used.

Contemporary trends in the management of aortic stenosis in the USA

AIMS

To assess the contemporary trends in aortic stenosis (AS) interventions in the USA before and after the introduction of transcatheter aortic valve implantation (TAVI).

METHODS AND RESULTS

We utilized the National-Inpatient-Sample to assess temporal trends in the incidence, cost, and outcomes of AS interventions between 1 January 2003 and 31 December 2016. During the study's period, AS interventions increased from 96 to 137 per 100 000 individuals > 60 years old, P < 0.001. In-hospital expenditure on AS interventions increased from $2.28 billion in 2003 to $4.33 in 2016 P < 0.001. Among patients who underwent aortic valve replacement, the proportion of TAVI increased from 11.9% in 2012 to 43.2% in 2016 (P < 0.001). Males and Hispanics had lower proportions of TAVI compared with females and White patients. Adjusted in-hospital mortality of isolated SAVR decreased from 5.4% in 2003 to 3.3% in 2016 (P < 0.001), whereas adjusted in-hospital mortality of TAVI decreased from 4.7% in 2012 to 2.2% in 2016, P < 0.001. The incidence of new dialysis, permanent pacemaker implantation, and blood transfusion decreased after both TAVI and SAVR between 2012 and 2016. However, the rate of post-operative stroke did not significantly decrease. Length of stay and cost of hospitalization decreased after both SAVR and TAVI, although the later remained higher with TAVI. Rates of non-home discharge decreased over time after TAVI but remained stable after isolated SAVR.

CONCLUSION

This nationwide survey documents the increasing incidence of AS interventions, the rising cost of modern AS care, and the paradigm shift in aortic valve replacement practice in the USA.

Real-World Health-Economic Considerations Around Aortic-Valve Replacement in a Publicly Funded Health System

Herein, we describe the unique interplay among biomedical ethics, principles of distributive justice, and economic theory to highlight the role of health technology assessments to compare therapeutic options for aortic valve replacement. From the perspective of the Canadian health care system, transcatheter aortic-valve implantation is associated with higher costs but also higher incremental health benefits compared with surgical aortic-valve replacement. At current willingness to pay thresholds, transcatheter aortic-valve replacement is likely cost effective across the spectrum of risk, from inoperable patients to those at low surgical risk. However, we highlight the nuances within each subgroup of surgical risk that merit careful consideration by the heart team. Moreover, incorporation of patients and their preferences in decision-making is key. In particular, in young, low-risk patients, there remains uncertainty regarding the optimal treatment, with unique concerns around valve durability, selection of valve prosthesis, and consideration for special procedures such as the Ross procedure. Nonetheless, current research suggests that, universally, patients prefer a less invasive approach compared with a more invasive approach. Finally, we highlight that there remain critical issues around timeliness of access to care and unacceptable geographic inequities across Canada. Further research into alternative funding mechanisms and integrated cross-sector care pathways is necessary to address these issues.

Cost-Effectiveness of Transcatheter Versus Surgical Aortic Valve Replacement in Low-Risk Patients With Severe Aortic Stenosis

BACKGROUND

Recent studies have shown that transcatheter aortic valve implantation (TAVI) is non-inferior to surgical aortic valve replacement (SAVR) for treatment of low-risk patients with severe aortic stenosis (AS). However, the cost-effectiveness of TAVI in this population is unknown. We sought to evaluate the cost-effectiveness of both balloon-expandable and self-expanding TAVI compared to SAVR in patients with severe AS at low operative risk.

METHODS

We developed a Markov model comparing TAVI to SAVR over a lifetime horizon. Key data inputs were drawn from the Placement of AoRTic TraNscathetER Valve (PARTNER) 3 trial for balloon-expandable TAVI and the Evolut Low-Risk trial for self-expanding TAVI. Costs were obtained from Australian sources. The perspective was that of the Australian health care system.

RESULTS

Although procedural costs were higher for TAVI compared to SAVR, these were offset by a shorter length of hospitalisation and lower acute complication costs in the TAVI group. Over a lifetime horizon, balloon-expandable TAVI was associated with increased costs of A$702 compared to SAVR, and increased quality-adjusted survival by 0.20 years, yielding an incremental cost-effectiveness ratio of A$3,521 per quality-adjusted life year (QALY) saved. Self-expanding TAVI was associated with lower lifetime costs compared to SAVR, and increased quality-adjusted survival by 0.08 years, and was therefore economically dominant. In probabilistic sensitivity analyses, balloon-expandable TAVI was cost-effective in 78% of iterations (at a cost-effectiveness threshold of A$50,000 per QALY gained) and self-expanding TAVI was cost-effective in 70% of iterations.

CONCLUSIONS

Among low-risk AS patients, both balloon-expandable and self-expanding TAVI are likely to be cost-effective relative to SAVR.

Decision analysis and personalized clinical tool for cerebrospinal fluid drains in thoracoabdominal aortic aneurysms repair

BACKGROUND AND AIM

The routine use of cerebrospinal fluid (CSF) drainage in patients undergoing operative repair of thoracoabdominal aneurysms (TAAA) has been associated with decreased rates of spinal cord ischemia. The use of CSF drains is not without consequence, however with complications including subarachnoid hemorrhage, epidural hematoma, meningitis, and, in 1% of cases, death. To date, a decision analysis tool to help clinicians decide when to use and not to use a CSF drain does not exist. In this analysis, we set out to develop a decision analysis tool for CSF drain placement in patients undergoing operative repair of TAAA.

METHODS

A Markov state-transition cohort model that compared TAAA repair with adjunctive CSF drain insertion to TAAA repair without drain insertion for the outcome of life expectancy was developed in TreeAge 2020. The cycle length was 1 month and the time horizon was 60 months.

RESULTS

The use of a CSF drain was associated with improved 5-year life expectancy (3.21 ± 0.10 vs. 3.09 ± 0.11 life-years gained). In the sensitivity analysis that varied the effectiveness of a CSF drain (odds ratio closer to 1 = less effective), the use of a CSF drain resulted in higher life expectancy in almost all scenarios.

CONCLUSIONS

The routine use of a CSF drain in patients undergoing TAAA repair is safe and effective, with few exceptions. This decision analysis tool can be used by clinicians to develop a personalized approach.

The cost-effectiveness of transcatheter aortic valve replacement in low surgical risk patients with severe aortic stenosis

Aims

The economic value of transcatheter aortic valve replacement (TAVR) in low surgical risk patients with severe, symptomatic aortic stenosis is not known. Our objective was to determine the cost-effectiveness of balloon-expandable TAVR and self-expandable TAVR relative to surgical aortic valve replacement (SAVR) in low-risk patients.

Methods and results

A fully probabilistic Markov cohort model was constructed to estimate differences in costs and effectiveness [quality-adjusted life years (QALYs)] over the patient’s life-time time from the third-party payer’s perspective. Clinical outcomes modelled were alive/well (no complications), permanent stroke, ≥moderate paravalvular leak, new pacemaker, rehospitalization, and death. A network meta-analysis of the PARTNER 3 and Evolut Low Risk trial was performed to compare balloon-expandable TAVR, self-expandable TAVR, and SAVR for the efficacy inputs. Incremental-cost effectiveness ratios (ICER) were calculated. The total life-time costs in the balloon-expandable TAVR, self-expandable-TAVR, and SAVR arms were $37  330 ± 4724, $39 660 ± 4862, and $34 583 ± 6731, respectively, and total life-time QALYs gained were 9.15 ± 3.23, 9.13 ± 3.23, and 9.05 ± 3.20, respectively. The ICERs for balloon-expandable TAVR and self-expandable TAVR against SAVR were $27 196/QALY and $59 641/QALY, respectively. Balloon-expandable TAVR was less costly and more effective than self-expandable TAVR. There was substantial uncertainty, with 53% and 58% of model iterations showing balloon-expandable TAVR to be the preferred option at willingness-to-pay thresholds of $50 000/QALY and $100  000/QALY, respectively.

Conclusion

Compared with SAVR, TAVR, particularly with balloon-expandable prostheses may be a cost-effective option for patients with severe aortic stenosis at low surgical risk.

A Canadian cost-effectiveness analysis of SAPIEN 3 transcatheter aortic valve implantation compared with surgery, in intermediate and high-risk severe aortic stenosis patients

Background and objectives: The treatment of severe aortic stenosis requires replacement of the defective native valve. Traditionally, this has been done via surgery, but in the last 10 years, transcatheter techniques have emerged. Transcatheter aortic valve implantation (TAVI) is a less invasive option compared to surgical aortic valve replacement (SAVR), and this study evaluates the cost-effectiveness of TAVI versus SAVR in intermediate and high surgical risk patients in Canada. Methods: A Markov model was used to project the costs and quality-adjusted life years (QALYs) gained for TAVI using the SAPIEN 3 valve and SAVR over a 15-year time horizon. The PARTNER I and II studies were used to populate the model in terms of survival, clinical event rates and quality of life over time. The costs of TAVI with SAPIEN 3 and SAVR as well as the costs associated with events included in the model were derived from Canadian administrative and literature data. Costs were expressed in 2018 Canadian dollars and all future costs and QALYs were discounted at a rate of 1.5% annually. Probabilistic and one-way sensitivity analyses were conducted. Results: The incremental cost-effectiveness ratios of TAVI using the SAPIEN 3 valve compared to surgery were $28,154 per QALY gained in intermediate risk patients and $17,237 per QALY gained in high-risk patients. The results of the probabilistic analyses indicated that at willingness-to-pay threshold of $50,000 per QALY gained, the probability of TAVI to be cost-effective was greater than 0.9 in both intermediate-risk and high-risk patients. Sensitivity analyses showed the results were most sensitive to the time horizon used. Conclusion: TAVI using the SAPIEN 3 valve is highly likely to be cost-effective in Canadian patients with severe aortic stenosis who are at intermediate and high surgical risk.

Why should we extend transcatheter aortic valve implantation to low-risk patients? A comprehensive review

Within the past decade, transcatheter aortic valve implantation (TAVI) has become established as the optimal treatment option for elderly, inoperable and high-risk patients with severe aortic stenosis, and is now recommended by international guidelines. Randomized controlled trials have demonstrated the non-inferiority of TAVI to open surgery in intermediate-risk patients and, most recently, in low-risk patients. Further randomized controlled trials are underway, but existing studies have already provided reassuring data in this cohort, and TAVI is offered routinely to younger and lower-risk patients in numerous centers. Improvements in the design of devices and delivery systems, accompanied by increased operator experience, have dramatically improved the safety of the procedure, and further expansion into low-risk groups seems inevitable once concerns about valve durability and device cost have been addressed. In this article, we provide a review of the existing literature, and estimate the clinical impact of TAVI in low-risk patients. Abbreviated title: Why should we extend TAVI to low-risk patients?

Cost-effectiveness analysis of the SAPIEN 3 TAVI valve compared with surgery in intermediate-risk patients

OBJECTIVE

Transcatheter aortic valve implantation (TAVI) has become the therapy of choice for treating severe aortic stenosis in patients at high-risk for surgery or where it is considered too risky to attempt. This uptake varies across geographies however, and its cost or value has frequently been cited as the reason for this. We sought to evaluate the potential cost and clinical impact of TAVI in intermediate risk patients from a French collective perspective.

MATERIALS AND METHODS

The analysis was performed using a novel Markov model with data derived from the PARTNER II randomized controlled trial for survival, clinical event rates, and quality-of-life. The simulated time horizon was 15 years, costs were from French sources and presented in 2016 Euros. Discounting of all outcomes was at 4% annually and the effect of uncertainty in model parameters was explored by deterministic and probabilistic sensitivity analysis (PSA).

RESULTS

In comparison to surgery, TAVI resulted in improved clinical outcomes (life expectancy and quality-adjusted life expectancy) and lower costs over a lifetime time horizon. The base case results showed increases of 0.42 years and 0.41 QALYs with lifetime cost savings of €439 for TAVI compared to surgery. PSA results showed a >50% likelihood of cost-effectiveness at €0 willingness-to-pay and a 100% likelihood at ∼€15,000.

LIMITATIONS

Clinically, survival projections are based on limited follow-up data and introduce uncertainty into the outcomes from the model. Economically, procedure costs are derived from a heterogeneous mix of patient risk groups, although this is much more likely to bias against TAVI and under-estimate overall cost savings.

CONCLUSIONS

In our analyses of intermediate risk patients, TAVI is associated with superior clinical outcomes compared to surgery and is cost saving. It could be expected that cost savings are conservative and likely to increase over time.

Appraisal of key trials in aortic and mitral fields

Aortic stenosis and mitral regurgitation are increasingly treated by percutaneous interventions including transcatheter aortic valve implantation (TAVI) and several mitral valve repair techniques, changing the landscape of valvular therapies in which surgery was predominant. Several randomised studies on TAVI have led to the use of this procedure in patients at intermediate or higher operative risk and have set strong foundations for future trials aiming to expand indications or to overcome several residual issues with TAVI. On the other hand, randomised evidence for percutaneous mitral valve repair (PMVR) techniques is still limited, supporting restricted indications to patients with high surgical risk when medical therapy fails. However, in the mitral field, several ongoing trials comparing PMVR with medical therapy or surgery will help to define optimal mitral regurgitation management in this era of evolving catheter-based treatment options. The present review will summarise randomised trials comparing TAVI or PMVR with medical therapy or surgery across the risk spectrum which have set the basis for guideline recommendations and for clinical use of transcatheter interventions. Characteristics, results, implications, unresolved issues and cost-effectiveness analysis of those trials, grouped according to the surgical risk of enrolled patients, will be appraised.

Transcatheter Aortic Valve Replacement and Concomitant Mitral Regurgitation

Mitral regurgitation frequently coexists in patients with severe aortic stenosis. Patients with moderate to severe mitral regurgitation at the time of transcatheter aortic valve replacement are at increased risk of future adverse events. Whether concomitant mitral regurgitation is independently associated with worse outcomes after TAVR remains a matter of debate. The optimal therapeutic strategy in these patients-TAVR with evidence-based heart failure therapy, combined TAVR and transcatheter mitral valve intervention, or staged transcatheter therapies-is ill-defined, and guideline-based recommendations in patients at increased risk for open heart surgery are lacking. Hence, a thorough evaluation of the aortic and mitral valve anatomy and function, along with an in-depth assessment of the patients' baseline risk profile, provides the basis for an individualized treatment approach. The aim of this review is therefore to give an overview of the current literature on mitral regurgitation in TAVR, focusing on different diagnostic and therapeutic strategies and optimal clinical decision making.