Geographic variation in aortic stenosis treatment and outcomes among Medicare beneficiaries in the United States.

BACKGROUND: Transcatheter aortic valve replacement (TAVR) has changed the landscape of aortic stenosis (AS) management. AIM: To describe and evaluate geographic variation in AS treatment and outcomes among a sample of Medicare beneficiaries. METHODS: A retrospective analysis of administrative claims data was conducted on a 20% sample of Medicare fee-for-service beneficiaries aged 65 and older with a diagnosis of AS (2015-2018). Estimates of demographic, comorbidity, and healthcare resources were obtained from Medicare claims and the Dartmouth Atlas of Health Care at the hospital referral region (HRR), which represents regional tertiary medical care markets. Linear regression was used to explain HRR-level variation in rates of surgical aortic valve replacement (SAVR) and TAVR, and 1-year mortality and readmission rates. RESULTS: A total of 740,899 beneficiaries with AS were identified with a median prevalence of AS of 39.9 per 1000 Medicare beneficiary years. The average HRR-level rate of SAVR was 26.3 procedures per 1000 beneficiary years and the rate of TAVR was 20.3 procedures per 1000 beneficiary years. HRR-level comorbidities and number of TAVR centers were associated with a lower SAVR rate. Demographics and comorbidities explained most of the variation in HRR-level 1-year mortality (15.2% and 18.8%) and hospitalization rates (20.5% and 16.9%), but over half of the variation remained unexplained. CONCLUSION: Wide regional variation in the treatment and outcomes of AS was observed but were largely unexplained by patient factors and healthcare utilization. Understanding the determinants of AS treatment and outcomes can inform population health efforts for these patients.

Racial and ethnic disparities in diagnosis, management and outcomes of aortic stenosis in the Medicare population.

IMPORTANCE: Aortic stenosis (AS) is one of the most common heart valve conditions and its incidence and prevalence increases with age. With the introduction of transcatheter aortic valve replacement (TAVR), racial and ethnic disparities in AS diagnosis, treatment and outcomes is poorly understood. OBJECTIVE: In this study we assessed racial and ethnic disparities in AS diagnosis, treatment, and outcomes among Medicare beneficiaries. DESIGN: We conducted a population-based cohort study of inpatient, outpatient, and professional claims from a 20% sample of Medicare beneficiaries. MAIN OUTCOMES AND MEASURES: Incidence and Prevalence was determined among Medicare Beneficiaries. Outcomes in this study included management; the number of (non)-interventional cardiology and cardiothoracic surgery evaluation and management (E&M) visits, and number of transthoracic echocardiograms (TTE) performed. Treatment, which was defined as Surgical Aortic Valve Replacement and Transthoracic Aortic Valve Replacement. And outcomes described as All-cause Hospitalizations, Heart Failure Hospitalization and 1-year mortality. RESULTS: A total of 1,513,455 Medicare beneficiaries were diagnosed with AS (91.3% White, 4.5% Black, 1.1% Hispanic, 3.1% Asian and North American Native) between 2010 and 2018. Annual prevalence of AS diagnosis was lower for racial and ethnic minorities compared with White patients, with adjusted rate ratios of 0.66 (95% CI 0.65 to 0.68) for Black patients, 0.67 (95% CI 0.64 to 0.70) for Hispanic patients and 0.75 (95% CI 0.73 to 0.77) for Asian and North American Native patients as recent as 2018. After adjusting for age, sex and comorbidities, cardiothoracic surgery E&M visits and treatment rates were significantly lower for Black, Hispanic and Asian and North American Native patients compared with White patients. All-cause hospitalization rate was higher for Black and Hispanic patients compared with White patient. 1-year mortality was higher for Black patients, while Hispanic and Asian and North American Native patients had lower 1-year mortality compared with White patients. CONCLUSIONS AND RELEVANCE: We demonstrated significant racial and ethnic disparities in the diagnosis, management and outcomes of AS. The factors driving the persistence of these disparities in AS care need to be elucidated to develop an equitable health care system.

Trends in Medicare Payments for Beneficiaries With Aortic Stenosis.

Background Aortic stenosis (AS) is the most common form of valvular heart disease with an increasing prevalence. Management of AS has changed dramatically with the introduction of transcatheter aortic valve replacement (AVR). The shift in management of AS, combined with an aging population, may increase the cost of patients with AS in the US health care system. Methods and Results We performed a retrospective cohort study, using inpatient, carrier, and outpatient data from a 20% Medicare fee-for-service beneficiaries' sample from 2008 to 2019 and included beneficiaries, aged ≥65 years. We identified beneficiaries with a diagnosis of AS and stratified the sample into 3 age groups: 66 to 74, 75 to 84, and ≥85 years. We evaluated the crude and adjusted changes in annual Medicare payments (total and component) per beneficiary. We identified 1 887 340 (1.6%) Medicare beneficiaries diagnosed with AS. The average annual spending for Medicare beneficiaries with AS was $19 241 in 2010 and increased annually by $301 to $23 174 in 2019 (P<0.0001). Annual Medicare payments on patients with AS increased from $2 894 995 131 in 2010 to $4 619 077 182 in 2019, a difference of >1.7 billion dollars. Inpatient spending increased 1.1% per year, with the highest increase in patients aged ≥85 years (1.9%). The percentage of beneficiaries undergoing surgical AVR decreased from 3.7% to 1.6%, and annual spending on surgical AVR decreased an average of 7.2% per year. The percentage of beneficiaries undergoing transcatheter AVR increased from 0% in 2010 to 3.8% in 2019, and annual spending for transcatheter AVR increased by 458.7% per year. Conclusions Although average annual Medicare spending per beneficiary modestly increased over the study period, the increase in the prevalence of AS and the proportion of beneficiaries undergoing (transcatheter) interventions for AS led to a substantial increase in overall Medicare spending among patients with AS.

Mapping pre-dissection aortic wall abnormalities: a multiparametric assessment.

OBJECTIVES: Maximal aortic diameter is commonly used to assess aortic risk but poorly predicts the timing and location of dissection events in patients with connective tissue disease who undergo regular imaging surveillance. Hence, we aimed to use available surveillance computed tomography angiography (CTA) scans to investigate the correlation between 3-dimensional (3D) growth and cyclic transmural wall stress with the location of intimal tear formation. METHODS: Three type B aortic dissection patients with 2 available electrocardiogram (ECG)-gated pre-dissection CTA scans and without surgical repair during the pre-dissection interval were retrospectively identified at our institution. Vascular deformation mapping was used to measure 3D aortic growth between 2 pre-dissection clinical CTA studies. In addition, we performed a computational analysis to estimate cyclic transmural wall stress in patient-specific baseline CTA geometries. RESULTS: In all 3 connective tissue disease patients, the site of type B aortic intimal tear co-localized with areas of peak 3D aortic wall growth. Aortic growth was detected by clinical radiological assessment in only 1 case. Co-localization of peak transmural stress and the site of intimal tear formation were found in all cases. CONCLUSIONS: Focal areas of growth and transmural wall stress co-localized with the site of intimal tear formation. These hypothesis-generating results suggest a possible new analytic pathway for a more sophisticated assessment of the factors leading to the initiation of dissection in patients with connective tissue disease. These methods could improve on current risk-stratification techniques.

The Effect of Hospital Market Competition on the Adoption of Transcatheter Aortic Valve Replacement.

BACKGROUND: The use of transcatheter aortic valve replacement (TAVR) has grown rapidly. The purpose of this study was to assess whether hospital market competition was associated with the use of TAVR. METHODS: We used 5 Healthcare Cost and Utilization Project state inpatient databases (Arizona, Florida, Iowa, Massachusetts, Washington) to identify patients undergoing TAVR (n = 5563) or surgical aortic valve replacement (n = 30,672) across 154 hospitals from 2011 to 2014. Using the Herfindahl-Hirschman Index (HHI) to calculate market competition, hospitals were categorized into commonly used categories of low (HHI >0.25), moderate (HHI 0.15-0.25), and high (HHI <0.15) competition. We associated market competition category with TAVR utilization using hierarchical logistic regression, adjusting for patient characteristics, hospital characteristics, year, and hospital random effect. We modeled associations between HHI category and in-hospital mortality, admission length of stay, and discharge to home as secondary outcomes. RESULTS: After adjustment, patients treated at high-competition hospitals had higher odds of receiving TAVR, relative to patients at low-competition hospitals (adjusted odds ratio [ORadj], 5.31; 95% confidence interval [CI], 2.10-13.4). TAVR use increased each year (ORadj, 1.73; 95% CI, 1.38-2.17) but was similar across HHI categories. Competition was not associated with in-hospital mortality or length of stay. Patients at high-competition hospitals were more likely to be discharged home (ORadj, 2.39; 95% CI, 1.23-4.66) compared with patients at low-competition hospitals. CONCLUSIONS: Market competition was positively associated with a hospital's adoption of TAVR. Future studies should further examine the impact of competition on quality and appropriateness.

Transcatheter Versus Surgical Aortic Valve Replacement Episode Payments and Relationship to Case Volume.

BACKGROUND: Transcatheter aortic valve replacement (TAVR) has increased in volume as an alternative to surgical aortic valve replacement (SAVR). Comparisons of total episode expenditures, although largely ignored thus far, will be key to the value proposition for payers. METHODS: We evaluated 6,359 Blue Cross Blue Shield of Michigan and Medicare fee-for-service beneficiaries undergoing TAVR (17 hospitals, n = 1,655) or SAVR (33 hospitals, n = 4,704) in Michigan between 2012 and 2016. Payments through 90 post-discharge days between TAVR and SAVR were price-standardized and risk-adjusted. Centers were divided into terciles of procedural volume separately for TAVR and SAVR, and payments were compared between lowest and highest terciles. RESULTS: Payments (± SD) were higher for TAVR than SAVR ($69,388 ± $22,259 versus $66,683 ± $27,377, p < 0.001), while mean hospital length of stay was shorter for TAVR (6.2 ± 5.6 versus 10.2 + 7.5 days, p < 0.001). Index hospitalization payments were $4,374 higher for TAVR (p < 0.001), whereas readmission and post-acute care payments were $1,150 (p = 0.001) and $739 (p = 0.004) lower, respectively, and professional payments were similar. For SAVR, high-volume centers had lower episode payments (difference: 5.0%, $3,255; p = 0.01) and shorter length of stay (10.0 ± 7.5 versus 11.1 ± 7.9 days, p = 0.002) than low volume centers. In contrast, we found no volume-payment relationship among TAVR centers. CONCLUSIONS: Episode payments were higher for TAVR, despite shorter length of stay. Although not a driver for TAVR, center SAVR volume was inversely associated with payments. These data will be increasingly important to address value-based reimbursement in valve replacement surgery.

Assessment of CardiOvascular Remodelling following Endovascular aortic repair through imaging and computation: the CORE prospective observational cohort study protocol.

INTRODUCTION: Thoracic aortic stent grafts are orders of magnitude stiffer than the native aorta. These devices have been associated with acute hypertension, elevated pulse pressure, cardiac remodelling and reduced coronary perfusion. However, a systematic assessment of such cardiovascular effects of thoracic endovascular aortic repair (TEVAR) is missing. The CardiOvascular Remodelling following Endovascular aortic repair (CORE) study aims to (1) quantify cardiovascular remodelling following TEVAR and compare echocardiography against MRI, the reference method; (2) validate computational modelling of cardiovascular haemodynamics following TEVAR using clinical measurements, and virtually assess the impact of more compliant stent grafts on cardiovascular haemodynamics; and (3) investigate diagnostic accuracy of ECG and serum biomarkers for cardiac remodelling compared to MRI. METHODS AND ANALYSIS: This is a prospective, nonrandomised, observational cohort study. We will use MRI, CT, echocardiography, intraluminal pressures, ECG, computational modelling and serum biomarkers to assess cardiovascular remodelling in two groups of patients with degenerative thoracic aneurysms or penetrating aortic ulcers: (1) patients managed with TEVAR and (2) control patients managed with medical therapy alone. Power analysis revealed a minimum total sample size of 20 patients (α=0.05, power=0.97) to observe significant left ventricular mass increase following TEVAR after 1 year. Consequently, we will include 12 patients in both groups. Advanced MRI sequences will be used to assess myocardial and aortic strain and distensibility, myocardial perfusion and aortic flow. ECG, echocardiography and serum biomarkers will be collected and compared against the imaging data. Computational models will be constructed from each patient imaging data, analysed and validated. All measurements will be collected at baseline (prior to TEVAR) and 1-year follow-up. The expected study period is 3 years. ETHICS AND DISSEMINATION: This study has been approved by the University of Michigan IRB. The results will be disseminated through scientific journals and conference presentations. TRIAL REGISTRATION NUMBER: NCT02735720.

A population-based analysis of endovascular versus open thoracic aortic aneurysm repair.

OBJECTIVE: The perioperative outcomes of open surgical and endovascular repair of intact thoracic aortic aneurysms (TAAs) during the last 3 months of 2005 were compared using a national administrative database. METHODS: The Nationwide Inpatient Sample was used to identify patients undergoing open aneurysm repair (OAR) or endovascular TAA repair (TEVAR) from October 1 to December 31, 2005. Patient demographic data, length of stay, hospital charges, patient disposition, and mortality were examined. Where appropriate, univariate tests of association used the chi(2) test, and multiple logistic regression analysis was used to determine predictors of in-hospital mortality, complications, and discharge status. RESULTS: A total of 1030 patients underwent open TAA repair and 267 underwent TEVAR. There was no significant difference in mortality between OAR and TEVAR (adjusted odds ratio [OR], 1.2; 95% confidence interval [CI], 0.73-2.12), although OAR patients were more likely to have cardiac, respiratory, and hemorrhagic complications. Patients undergoing TEVAR were more likely to be discharged to home (adjusted OR, 6.37; 95% CI, 2.93-13.70) and had a decreased length of stay (5.7 days vs 9.9 days; P = .0015). The differences in hospital charges and costs were not significant. CONCLUSION: Although further study is warranted, this study of a national sample suggests that endovascular TAA repair is safe in the short-term, associated with fewer cardiac, respiratory, and hemorrhagic complications, and requires a shorter hospital stay.