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.

Health-related quality of life and lived experiences in males and females with thoracic aortic disease and their partners.

OBJECTIVE: Thoracic aortic disease (TAD) may have substantial impact on health-related quality of life (HRQOL). We described HRQOL in patients with TAD, cardiovascular screening participants and their partners; identified factors associated with HRQOL; and explored lived experiences and feelings of anxiety or depression using a mixed methods design. METHODS: For this cross-sectional study, all consecutive patients visiting the TAD outpatient clinic (2017-2019) at our centre were asked to complete three questionnaires: the Short Form 36 (SF-36), the Hospital Anxiety and Depression Scale (HADS) and the Rotterdam Disease Specific Questionnaire (RDSQ). A subsample was invited for in-depth interviews. RESULTS: In total, 261 participants were included: 147 patients with TAD (thoracic aortic diameter ≥40 mm; 54 females, 36.7%), 114 screening participants (cardiovascular family screening; 71 females, 62.3%) and 66 partners. Compared with the general population, patients with TAD showed markedly lower HRQOL, whereas screening participants' HRQOL was less impaired. Female and younger participants scored significantly lower on the SF-36 and HADS compared with male and older participants. Smaller aortic diameter was associated with better RDSQ score, and previous aortic surgery was associated with higher HADS depression scores. Furthermore, partners scored significantly lower on 2/8 SF-36 subdomains when compared with the general population. From 11 interviewees, determinants of psychological distress included coping strategies, impact on social and professional life, disease-related knowledge, state of aortic diameters and physical symptoms. CONCLUSIONS: Healthcare professionals must be aware of HRQOL impairments in patients with TAD, particularly in younger females. Moreover, attention for partners is needed. Coping strategies and communication within the family were found to be important factors influencing psychological distress, and might be valuable leads for counselling and HRQOL improvement in this population.

Early cost-utility analysis of tissue-engineered heart valves compared to bioprostheses in the aortic position in elderly patients.

OBJECTIVES: Aortic valve disease is the most frequent indication for heart valve replacement with the highest prevalence in elderly. Tissue-engineered heart valves (TEHV) are foreseen to have important advantages over currently used bioprosthetic heart valve substitutes, most importantly reducing valve degeneration with subsequent reduction of re-intervention. We performed early Health Technology Assessment of hypothetical TEHV in elderly patients (≥ 70 years) requiring surgical (SAVR) or transcatheter aortic valve implantation (TAVI) to assess the potential of TEHV and to inform future development decisions. METHODS: Using a patient-level simulation model, the potential cost-effectiveness of TEHV compared with bioprostheses was predicted from a societal perspective. Anticipated, but currently hypothetical improvements in performance of TEHV, divided in durability, thrombogenicity, and infection resistance, were explored in scenario analyses to estimate quality-adjusted life-year (QALY) gain, cost reduction, headroom, and budget impact. RESULTS: Durability of TEHV had the highest impact on QALY gain and costs, followed by infection resistance. Improved TEHV performance (- 50% prosthetic valve-related events) resulted in lifetime QALY gains of 0.131 and 0.043, lifetime cost reductions of €639 and €368, translating to headrooms of €3255 and €2498 per hypothetical TEHV compared to SAVR and TAVI, respectively. National savings in the first decade after implementation varied between €2.8 and €11.2 million (SAVR) and €3.2-€12.8 million (TAVI) for TEHV substitution rates of 25-100%. CONCLUSIONS: Despite the relatively short life expectancy of elderly patients undergoing SAVR/TAVI, hypothetical TEHV are predicted to be cost-effective compared to bioprostheses, commercially viable and result in national cost savings when biomedical engineers succeed in realising improved durability and/or infection resistance of TEHV.

What Is the Potential of Tissue-Engineered Pulmonary Valves in Children?

BACKGROUND: As a living heart valve substitute with growth potential and improved durability, tissue-engineered heart valves (TEHVs) may prevent reinterventions that are currently often needed in children with congenital heart disease. We performed early health technology assessment to assess the potential cost-effectiveness of TEHVs in children requiring right ventricular outflow tract reconstruction (RVOTR). METHODS: A systematic review and meta-analysis was conducted of studies reporting clinical outcome after RVOTR with existing heart valve substitutes in children (mean age ≤12 years or maximum age ≤21 years) published between January 1, 2000, and May 2, 2018. Using a patient-level simulation model, costs and effects of RVOTR with TEHVs compared with existing heart valve substitutes were assessed from a health care perspective applying a 10-year time horizon. Improvements in performance of TEHVs, divided in durability, thrombogenicity, and infection resistance, were explored to estimate quality-adjusted life year (QALY) gain, cost reduction, headroom, and budget impact associated with TEHVs. RESULTS: Five-year freedom from reintervention after RVOTR with existing heart valve substitutes was 46.1% in patients less than or equal to 2 years of age and 81.1% in patients greater than 2 years of age. Improvements in durability had the highest impact on QALYs and costs. In the improved TEHV performance scenario (durability ≥5 years and -50% other valve-related events), QALY gain was 0.074 and cost reduction was €10,378 per patient, translating to maximum additional costs of €11,856 per TEHV compared with existing heart valve substitutes. CONCLUSIONS: This study showed that there is room for improvement in clinical outcomes in children requiring RVOTR. If TEHVs result in improved clinical outcomes, they are expected to be cost-effective compared with existing heart valve substitutes.

How much does a heart valve implantation cost and what are the health care costs afterwards?

Objective: In the era of limited healthcare budgets, healthcare costs of heart valve implantations need to be considered to inform cost-effectiveness analyses. We aimed to provide age group-specific costs estimates of heart valve implantations, related complications and other healthcare utilisation following the intervention. Methods: We performed retrospective analyses of healthcare costs of patients who had undergone heart valve implantations in 2010-2013 and controls using claims data from Dutch health insurers. Heart valve implantations included surgical valve replacement and transcatheter valve implantation in all heart valve positions. Patients were divided in four age groups. Control groups were created by taking random samples of the Dutch population stratified by age, gender, socioeconomic status and comorbidities. We applied non-parametric bootstrapping to address uncertainty of the cost estimates. The association of patient and intervention characteristics with costs was determined by (multilevel) generalised linear models. Results: The baseline characteristics of 18 903 patients and 188 925 controls were comparable. The annual healthcare costs were substantially higher for surgical heart valve replacement patients than for controls, especially in the year of heart valve implantation. Factors associated with increased annual healthcare costs for patients were older age, female gender, comorbidities, low socioeconomic status and complications. Conclusions: We provided a comprehensive overview of age group-specific incidence of heart valve implantations, subsequent survival and complications as well as associated healthcare costs of all patients in the Netherlands. Our results provide real-world costs estimates that can be used as a benchmark for costs of future innovative heart valve implantations.

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.

Conceptual model for early health technology assessment of current and novel heart valve interventions.

OBJECTIVE: The future promises many technological advances in the field of heart valve interventions, like tissue-engineered heart valves (TEHV). Prior to introduction in clinical practice, it is essential to perform early health technology assessment. We aim to develop a conceptual model (CM) that can be used to investigate the performance and costs requirements for TEHV to become cost-effective. METHODS: After scoping the decision problem, a workgroup developed the draft CM based on clinical guidelines. This model was compared with existing models for cost-effectiveness of heart valve interventions, identified by systematic literature search. Next, it was discussed with a Delphi panel of cardiothoracic surgeons, cardiologists and a biomedical scientist (n=10). RESULTS: The CM starts with the valve implantation. If patients survive the intervention, they can remain alive without complications, die from non-valve-related causes or experience a valve-related event. The events are separated in early and late events. After surviving an event, patients can experience another event or die due to non-valve-related causes. Predictors will include age, gender, NYHA class, left ventricular function and diabetes. Costs and quality adjusted life years are to be attached to health conditions to estimate long-term costs and health outcomes. CONCLUSIONS: We developed a CM that will serve as foundation of a decision-analytic model that can estimate the potential cost-effectiveness of TEHV in early development stages. This supports developers in deciding about further development of TEHV and identifies promising interventions that may result in faster take-up in clinical practice by clinicians and reimbursement by payers.

Development and validation of a cardiovascular risk assessment model in patients with established coronary artery disease.

Appropriate risk stratification of patients with established, stable coronary artery disease could contribute to the prevention of recurrent cardiovascular events. The purpose of the present study was to develop and validate risk prediction models for various cardiovascular end points in the EURopean trial On reduction of cardiac events with Perindopril in stable coronary Artery disease (EUROPA) database, consisting of 12,218 patients with established coronary artery disease, with a median follow-up of 4.1 years. Cox proportional hazards models were used for model development. The end points examined were cardiovascular mortality, noncardiovascular mortality, nonfatal myocardial infarction, coronary artery bypass grafting, percutaneous coronary intervention, resuscitated cardiac arrest, and combinations of these end points. The performance measures included Nagelkerke's R², time-dependent area under the receiver operating characteristic curves, and calibration plots. Backward selection resulted in a prediction model for cardiovascular mortality (464 events) containing age, current smoking, diabetes mellitus, total cholesterol, body mass index, previous myocardial infarction, history of congestive heart failure, peripheral vessel disease, previous revascularization, and previous stroke. The model performance was adequate for this end point, with a Nagelkerke R² of 12%, and an area under the receiver operating characteristic curve of 0.73. However, the performance of models constructed for nonfatal and combined end points was considerably worse, with an area under the receiver operating characteristic curve of about 0.6. In conclusion, in patients with established coronary artery disease, the risk of cardiovascular mortality during longer term follow-up can be adequately predicted using the clinical characteristics available at baseline. However, the prediction of nonfatal outcomes, both separately and combined with fatal outcomes, poses major challenges for clinicians and model developers.

Data Resource Profile: adult cardiac surgery database of the Netherlands Association for Cardio-Thoracic Surgery.

In 2007 The Netherlands Association for Cardio-Thoracic Surgery (Nederlandse Vereniging voor Thoraxchirurgie, NVT) instituted the Adult Cardiac Surgery Database. The dataset comprises demographic factors, type of intervention, in-hospital mortality and 18 risk factors for mortality after cardiac surgery, according to the European System for Cardiac Operative Risk Evaluation definitions. Currently, this procedural database contains over 60 000 interventions. Completeness of data is excellent and national coverage of all 16 Dutch cardio-thoracic surgery centres has been achieved since the start. The primary goal of the database is to control and maintain the quality of care by evaluation of outcomes. This is accomplished by regular feedback and comparison of outcomes. For a subset of the database (procedures from 10 out of 16 centres) longer-term follow-up has been established by means of data linkage to two national registries. This provides information on survival status, causes of death and readmissions. The database has recently been used for research, resulting in methodological papers aimed at optimizing comparison of outcomes. In future, clinical issues will also be addressed, for example survival after coronary artery bypass grafting and valve surgery.

Microsimulation for clinical decision-making in individual patients with established coronary artery disease: a concept.

BACKGROUND: In cardiovascular disease, numerous evidence-based prognostic models have been created, usually based on regression analyses of isolated patient datasets. They tend to focus on one outcome event, based on just one baseline evaluation of the patient, and fail to take the disease process in its dynamic nature into account. We present so-called microsimulation as an attractive alternative for clinical decision-making in individual patients. We aim to further familiarize clinicians with the concept of microsimulation and to inform them about the modeling process. METHODS AND RESULTS: We describe the modeling process, advantages and disadvantages of microsimulation. We illustrate the concept using a hypothetical 60-year-old patient, with several cardiac risk factors, who is hospitalized for myocardial infarction. By using microsimulation, we calculate this patient's probability of death. In our example, this particular patient's estimated life expectancy turns out to be 8.9 years. While calculating this life expectancy, we were able to account for multiple outcome events and changing patient characteristics. CONCLUSIONS: Microsimulation takes into account the dynamic nature of coronary artery disease by estimating most likely outcomes regarding a broad range of clinical events. Moreover, microsimulation can be used to evaluate treatment effects by estimating the event-free life expectancy with and without treatment. Hence, microsimulation has several advantages compared to modeling techniques such as regression.

Anatomical and functional assessment of single left internal mammary artery versus arterial T-grafts 12 years after surgery.

We determined whether ultrasonographic left internal mammary artery (LIMA) findings correspond with 64 multislice computed tomography (MSCT) in patients 12 years after coronary artery bypass grafting. We included 34 patients (63.2+/-9.2 years), 16 with conventional single LIMA (group I) and 18 arterial T-grafts (group II), in a cross-sectional study. Patients underwent transthoracic proximal LIMA ultrasonography at rest and during the Azoulay maneuver, transthoracic echocardiography of the left ventricle and 64-MSCT, 11.5+/-1.4 years postoperatively. MSCT scans showed three string sign LIMA grafts (19%) in group I and three distal string sign LIMA grafts (17%) and 16 occluded T-graft anastomoses (22%) in group II. LIMA diameters and areas are significantly larger in group II in the origin, 3.5+/-0.7 vs. 2.5+/-0.5 mm, P=0.00007 and 0.09+/-0.04 vs. 0.05+/-0.02 cm(2), P=0.00019 and in the third intercostal space, 3.4+/-0.7 vs. 2.5+/-0.5 mm, P=0.00009 and 0.09+/-0.03 vs. 0.05+/-0.02 cm(2), P=0.000047. Most ultrasonographic LIMA findings do not differ between the groups. Thus, proximal LIMA diameters and areas are significantly larger in T-grafts and ultrasonographic variables equalize between the groups at rest and during the Azoulay maneuver 12 years after surgery.

Serial echocardiographic assessment of neo-aortic regurgitation and root dimensions after the modified Ross procedure.

BACKGROUND AND AIM OF THE STUDY: Concern exists regarding progressive root dilatation after the modified Ross procedure. The present prospective echocardiographic study aimed to provide further insight into neo-aortic regurgitation (nAR) and neoaortic root dimensions over time in adult Rotterdam Ross root patients, and to study potential risk factors for nAR and dilatation. METHODS: All Rotterdam Ross patients aged > or = 16 years at surgery were subjected to a prospective biennial standardized echocardiographic protocol. Analysis over time of nAR according to the jet length and jet diameter method, autograft annulus and sinotubular junction (STJ) diameters was carried out using a multilevel linear model in 90 patients who had two or more echocardiographic measurements (mean 5; range 2-9; total 458) up to 14 years (mean 7 years) after surgery. RESULTS: The mean (+/- SE) initial postoperative jet length nAR was grade 0.9 +/- 0.09, and the annual increase 0.1 +/- 0.02 (p < 0.001). Initial annulus and STJ diameters were 25 +/- 0.5 mm and 36 +/- 0.6 mm, while annual increases were 0.4 +/- 0.07 mm and 0.5 +/- 0.09 mm, respectively (p < 0.001). Patients who eventually underwent an autograft reoperation (n = 10) had significantly greater initial nAR and greater progression of nAR, and a greater initial annulus diameter. The annual annulus and STJ diameter increase was greater in patients who underwent autograft reoperation. Compared to freestanding root replacement, patients with inclusion cylinder aortic root replacement had smaller initial annulus and STJ diameters that did not increase over time. Female gender was associated with a greater initial jet length and jet diameter nAR and a greater increase over time in jet diameter nAR. Preoperative aortic regurgitation or combined aortic stenosis and regurgitation were associated with greater initial annulus and STJ diameters. Neither bicuspid valve disease, patient age, preoperative ascending aorta aneurysm, prior aortic valve surgery nor hypertension had an effect on initial or progression of nAR, annulus, and STJ diameter. CONCLUSION: The annual increase in nAR and root dimensions is small, but persistent, after autograft aortic root replacement in adults, and further reoperations should be anticipated. Use of the inclusion cylinder root replacement technique seems to prevent neo-aortic dilatation.