Cost effectiveness of transcatheter aortic valve replacement compared with medical management or surgery for patients with aortic stenosis

The economics of TAVI: A systematic review

Objective

The scope of this systematic review is to update the existing body of evidence regarding the cost-effectiveness of transcatheter aortic valve implantation, stratified across all risk categories, and to assess their methodological quality.

Methods

A systematic review was performed including published cost-effectiveness analyses of heart valve implantations. The quality was assessed with the Quality of Health Economics Tool.

Results

We identified 33 economic evaluations of transcatheter aortic heart valve implantations. Results were not consistent, ranging from dominant to dominating. Moreover, the models were sensitive to an array of variables. The methodological quality of the studies was good.

Conclusion

This systematic review led to inconclusive and inconsistent results pertinent to the economic profile of TAVI technology. It also highlighted areas which merit further research regarding the pillars of cost-effectiveness analysis such as modeling, the extrapolation of available data and the uncertainty of the evidence. A thorough assessment of the patient should proceed any decision-making.

Contemporary review of severe aortic stenosis

Severe aortic stenosis (AS) is the most common form of valvular heart disease in the developed world, with a rising prevalence due to an ageing Australian population. Transcatheter aortic valve implantation (TAVI) offers a less invasive option for the treatment of severe AS, with evidence supporting TAVI compared with medical therapy in inoperable patients and superior with surgical aortic valve replacement (SAVR) in high-risk patients. Equal outcomes have been observed in all-comer intermediate-risk populations. The Heart Team utilises a shared decision-making approach between physicians and surgeons in risk-stratifying patients and reduces the intrinsic bias that may occur if decisions are made in isolation. Geriatric assessment is useful for identifying preoperative frailty, a major risk factor for death post-aortic valve intervention. In severe AS, a decision can be made collaboratively to pursue TAVI, SAVR, a Ross Procedure or conservative management. The learning curve associated with TAVI has improved markedly, with overall complication rates decreasing around the world. Contemporary changes in practice, such as conscious sedation without general anaesthesia, expedited recovery and early discharge, will likely improve cost-effectiveness. In 2018, TAVI is a well-established procedure in Australia that has revolutionised the management of severe AS. In the future, with an expanding elderly population, the number of patients to benefit from transcatheter therapies for severe AS is hypothesised to increase 4-10-fold. Heart Team assessment is crucial in patients with severe AS to direct appropriate management.

Systematic review of model-based economic evaluations of heart valve implantations

OBJECTIVE

To review the evidence on the cost-effectiveness of heart valve implantations generated by decision analytic models and to assess their methodological quality.

METHODS

A systematic review was performed including model-based cost-effectiveness analyses of heart valve implantations. Study and model characteristics and cost-effectiveness results were extracted and the methodological quality was assessed using the Philips checklist.

RESULTS

Fourteen decision-analytic models regarding the cost-effectiveness of heart valve implantations were identified. In most studies transcatheter aortic valve implantation (TAVI) was cost-effective compared to standard treatment (ST) in inoperable or high-risk operable patients (ICER range 18,421-120,779 €) and in all studies surgical aortic valve replacement (SAVR) was cost-effective compared to ST in operable patients (ICER range 14,108-40,944 €), but the results were not consistent on the cost-effectiveness of TAVI versus SAVR in high-risk operable patients (ICER range: dominant to dominated by SAVR). Mechanical mitral valve replacement (MVR) had the lowest costs per success compared to mitral valve repair and biological MVR. The methodological quality of the studies was moderate to good.

CONCLUSION

This review showed that improvements can be made in the description and justification of methods and data sources, sensitivity analysis on extrapolation of results, subgroup analyses, consideration of methodological and structural uncertainty, and consistency (i.e. validity) of the models. There are several opportunities for future decision-analytic models of the cost-effectiveness of heart valve implantations: considering heart valve implantations in other valve positions besides the aortic valve, using a societal perspective, and developing patient-simulation models to investigate the impact of patient characteristics on outcomes.

Two-year post-discharge costs of care among patients treated with transcatheter or surgical aortic valve replacement in Germany

Background

This study presents data on post-discharge costs of care among patients treated with transcatheter or surgical aortic valve replacement over a two year period.

Methods

Based on a prospective clinical trial, post-discharge utilization of health services and status of assistance were collected for 151 elderly patients via 2250 monthly telephone interviews, valued using standardized unit costs and analysed using two-part regression models.

Results

At month 1 post-discharge, total costs of care are substantially elevated (monthly mean: €3506.7) and then remain relatively stable over the following 23 months (monthly mean: €622.3). As expected, the majority of these costs are related to in-hospital care (~98% in month 1 post-discharge and ~72% in months 2–24). Patients that died during follow-up were associated with substantially higher cost estimates of in-hospital care than those surviving the two-year study period, while patients’ age and other patient characteristics were of minor relevance. Estimated costs of outpatient care are lower at month 1 than during the rest of the study period, and not affected by the event of death during follow-up. The estimated costs of nursing care are, in contrast, much higher in year 2 than in year 1 and differ substantially by gender and type of procedure as well as by patients’ age. Overall, these monthly cost estimates add up to €10,352 for the first and €7467.6 for the second year post-discharge.

Conclusions

Substantial cost increases at month 1 post-discharge and in case of death during follow-up are the main findings of the study, which should be taken into account in future economic evaluations on the topic. Application of standardized unit costs in combination with monthly patient interviews allows for a far more precise estimate of the variability in post-discharge health service utilization in this group of patients than the ones given in previous studies.

Trial registration

German Clinical Trial Register Nr. DRKS00000797.

Electronic supplementary material

The online version of this article (doi:10.1186/s12913-017-2432-8) contains supplementary material, which is available to authorized users.

Simulation for transthoracic echocardiography of aortic valve

Simulation allows interactive transthoracic echocardiography (TTE) learning using a virtual three-dimensional model of the heart and may aid in the acquisition of the cognitive and technical skills needed to perform TTE. The ability to link probe manipulation, cardiac anatomy, and echocardiographic images using a simulator has been shown to be an effective model for training anesthesiology residents in transesophageal echocardiography. A proposed alternative to real-time reality patient-based learning is simulation-based training that allows anesthesiologists to learn complex concepts and procedures, especially for specific structures such as aortic valve.

Drivers of healthcare costs associated with the episode of care for surgical aortic valve replacement versus transcatheter aortic valve implantation

Objective

Transcatheter aortic valve implantation (TAVI) is generally more expensive than surgical aortic valve replacement (SAVR) due to the high cost of the device. Our objective was to understand the patient and procedural drivers of cumulative healthcare costs during the index hospitalisation for these procedures.

Design

All patients undergoing TAVI, isolated SAVR or combined SAVR+coronary artery bypass grafting (CABG) at 7 hospitals in Ontario, Canada were identified during the fiscal year 2012–2013. Data were obtained from a prospective registry. Cumulative healthcare costs during the episode of care were determined using microcosting. To identify drivers of healthcare costs, multivariable hierarchical generalised linear models with a logarithmic link and γ distribution were developed for TAVI, SAVR and SAVR+CABG separately.

Results

Our cohort consisted of 1310 patients with aortic stenosis, of whom 585 underwent isolated SAVR, 518 had SAVR+CABG and 207 underwent TAVI. The median costs for the index hospitalisation for isolated SAVR were $21 811 (IQR $18 148–$30 498), while those for SAVR+CABG were $27 256 (IQR $21 741–$39 000), compared with $42 742 (IQR $37 295–$56 196) for TAVI. For SAVR, the major patient-level drivers of costs were age >75 years, renal dysfunction and active endocarditis. For TAVI, chronic lung disease was a major patient-level driver. Procedural drivers of cost for TAVI included a non-transfemoral approach. A prolonged intensive care unit stay was associated with increased costs for all procedures.

Conclusions

We found wide variation in healthcare costs for SAVR compared with TAVI, with different patient-level drivers as well as potentially modifiable procedural factors. These highlight areas of further study to optimise healthcare delivery.

Prognostic performance of critical care scores in patients undergoing transcatheter aortic valve implantation

BACKGROUND

Critical care management of patients undergoing transcatheter aortic valve implantation (TAVI) is a major determinant of their outcome.

AIMS

The aim of this study was to compare the prognostic performance of four general scoring systems [Acute Physiology and Chronic Health Evaluation (APACHE), Simplified Acute Physiology Score (SAPS), Sequential Organ Failure Assessment (SOFA), and MultiOrgan Dysfunction (MOD) scores] in TAVI patients.

METHODS

Between 1 June 2008 and 30 June 2014, 75 patients (81.2 ± 6.4 years old, 36 men and 39 women) who underwent TAVI were scored during the first 24 h of their stay at the intensive care unit (ICU). The outcome measures were in-hospital and 30-day mortality and in-hospital and 30-day morbidity defined as myocardial infarction, implantation of permanent pacemaker, stroke, tamponade, major bleeding, vascular access site complications and prolonged ventilation.

RESULTS

Four patients (5.3%) died in ICU and one more during follow-up, indicating a 30-day mortality rate of 6.6%. Regarding in-hospital mortality, the area under the ROC curve (AUC) was 0.92 for SAPS II, 0.88 for APACHE II, 0.73 for MODS and 0.74 for SOFA. Regarding 30 day-mortality, SAPS II and APACHE II performed equally higher (AUC = 0.88) than the other two scores (0.79 for MODS and 0.80 for SOFA). SAPS II had the best calibration among all four scores for in-hospital and 30-day mortality (χ²= 3.06 and χ²= 3.29, respectively). AUCs for in-hospital and 30-day morbidity were above 0.7 for SAPS II and APACHE II.

CONCLUSIONS

SAPS II and APACHE II are reliable mortality and morbidity risk stratification models for TAVI patients with high calibration and discrimination.