Unplanned postoperative catheterization during admission for coronary artery bypass grafting is neither cheap nor benign, but may rescue patients

OBJECTIVE

Literature describing outcomes of myocardial ischemia after coronary artery bypass grafting is sparse. We hypothesized these patients had more complications and incurred higher costs of care.

METHODS

Using adult cardiac surgery data and cardiac catheterization (CathPCI) data from the Virginia Cardiac Services Quality Initiative, we identified patients who underwent unplanned cardiac catheterization after coronary artery bypass grafting from 2018 to 2021. Adult cardiac surgery data were matched to CathPCI data examining earliest in-hospital catheterization. Patients not requiring catheterization served as the control group.

RESULTS

We identified 10,597 patients who underwent isolated coronary artery bypass grafting, of whom 41 of 10,597 underwent unplanned cardiac catheterization. A total of 21 of 41 patients (51%) received percutaneous coronary intervention, most commonly for non-ST-elevation myocardial infarction (n = 7, 33%) and ST-elevation myocardial infarction (n = 6, 29%). Postoperative cardiac arrest occurred in 14 patients (40%). In patients who underwent percutaneous coronary intervention, 14 (67%) had a single lesion, 4 (19%) had 2 lesions, and 3 (14%) had 3 lesions. The left anterior descending artery (38%) was the most frequently intervened upon vessel. Patients who underwent catheterization were more likely to require balloon pump support (26% vs 11%), to have prolonged ventilation (57% vs 20%), to have renal failure (17% vs 7.1%), and to undergo reintubation (37% vs 3.8%, all P < .04). There was no statistical difference in operative mortality (4.9% vs 2.3%, P = .2) or failure to rescue (4.9% vs 1.6%, P = .14). Total costs were higher in patients who underwent unplanned catheterization ($81,293 vs $37,011, P < .001).

CONCLUSIONS

Unplanned catheterization after coronary artery bypass grafting is infrequent but associated with more complications and a higher cost of care. Therefore, determination of an association with operative mortality in patients with suspected ischemia after coronary artery bypass grafting requires additional study.

Machine learning prediction of hospitalization costs for coronary artery bypass grafting operations

BACKGROUND

With the steady rise in health care expenditures, the examination of factors that may influence the costs of care has garnered much attention. Although machine learning models have previously been applied in health economics, their application within cardiac surgery remains limited. We evaluated several machine learning algorithms to model hospitalization costs for coronary artery bypass grafting.

METHODS

All adult hospitalizations for isolated coronary artery bypass grafting were identified in the 2016 to 2020 Nationwide Readmissions Database. Machine learning models were trained to predict expenditures and compared with traditional linear regression. Given the significance of postoperative length of stay, we additionally developed models excluding postoperative length of stay to uncover other drivers of costs. To facilitate comparison, machine learning classification models were also trained to predict patients in the highest decile of costs. Significant factors associated with high cost were identified using SHapley Additive exPlanations beeswarm plots.

RESULTS

Among 444,740 hospitalizations included for analysis, the median cost of hospitalization in coronary artery bypass grafting patients was $43,103. eXtreme Gradient Boosting most accurately predicted hospitalization costs, with R2 = 0.519 over the validation set. The top predictive features in the eXtreme Gradient Boosting model included elective procedure status, prolonged mechanical ventilation, new-onset respiratory failure or myocardial infarction, and postoperative length of stay. After removing postoperative length of stay, eXtreme Gradient Boosting remained the most accurate model (R2 = 0.38). Prolonged ventilation, respiratory failure, and elective status remained important predictive parameters.

CONCLUSION

Machine learning models appear to accurately model total hospitalization costs for coronary artery bypass grafting. Future work is warranted to uncover other drivers of costs and improve the value of care in cardiac surgery.

Clinical and financial outcomes associated with the utilization of right internal mammary artery versus radial artery in multivessel coronary artery bypass grafting

BACKGROUND

Multi-arterial coronary bypass grafting with the left internal mammary artery as a conduit has been shown to offer superior long-term survival compared to single-arterial coronary bypass grafting. Nevertheless, the selection of a secondary conduit between the right internal mammary artery and the radial artery remains controversial. Using a national cohort, we examined the relationships between the right internal mammary artery and the radial artery with acute clinical and financial outcomes.

METHODS

Adults undergoing on-pump multivessel coronary bypass grafting with left internal mammary artery as the first arterial conduit were identified in the 2016 to 2020 Nationwide Readmissions Database. Patients receiving either the right internal mammary artery or the radial artery, but not both, were included in the analysis. Multivariable regression models were fitted to examine the association between the conduits and in-hospital mortality, as well as additional secondary outcomes.

RESULTS

Of an estimated 49,798 patients undergoing multi-arterial coronary bypass grafting, 29,729 (59.7%) comprised the radial artery cohort. During the study period, the proportion of multi-arterial coronary bypass grafting utilizing the radial artery increased from 51.3% to 65.2% (nptrend <0.001). Following adjustment, the radial artery was associated with reduced odds of in-hospital mortality (adjusted odds ratio 0.44), prolonged mechanical ventilation (adjusted odds ratio 0.78), infectious complications (adjusted odds ratio 0.69), and 30-day nonelective readmission (adjusted odds ratio 0.77, all P < .05).

CONCLUSION

Despite no definite endorsement from surgical societies, the radial artery is increasingly utilized as a secondary conduit in multi-arterial coronary bypass grafting. Compared to the right internal mammary artery, the radial artery was associated with lower odds of in-hospital mortality, complications, and reduced healthcare expenditures. These results suggest that whenever feasible, the radial artery should be the favored conduit over the right internal mammary artery. Nevertheless, future studies examining long-term outcomes associated with these vessels remain necessary.

Cost Analysis of Robot-Assisted Versus On-Pump and Off-Pump Coronary Artery Bypass Grafting: A Single-Center Surgical and 30-Day Outcomes Comparison

OBJECTIVE

Throughout Europe, the interest in implementing robot-assisted minimally invasive direct coronary artery bypass (RA-MIDCAB) has been growing. However, concerns about additional costs have emerged concurrently. In this analysis, we aim to provide a comparison of the cumulative perioperative costs of RA-MIDCAB, on-pump coronary artery bypass grafting (CABG), and off-pump CABG (OPCAB).

METHODS

We conducted a propensity score-matched analysis comparing patients undergoing RA-MIDCAB with those undergoing CABG or OPCAB at our institution from January 2016 to December 2021. After matching, we analyzed the combined intraoperative surgical costs and 30-day postoperative costs. We first compared RA-MIDCAB costs to CABG and then to OPCAB separately. Violin plots illustrated the cost distribution among individual patients. Total cost uncertainty was estimated using 1,000 bootstrapping iterations.

RESULTS

Seventy-nine RA-MIDCAB patients were matched to 158 CABG patients, and 80 RA-MIDCAB patients were matched to 149 OPCAB patients. Considering both surgical and clinical outcomes, RA-MIDCAB yielded an average cost of €17,121 per patient (€16,781 to €33,294), CABG was €16,571 per patient (€16,664 to €41,860), and OPCAB was €15,463 per patient (€10,895 to €57,867). After bootstrap iterations, RA-MIDCAB was found to be €472 (2.8%) and €1,599 (10.3%) more expensive per patient than CABG and OPCAB, respectively.

CONCLUSIONS

In The Netherlands, the adoption of RA-MIDCAB did not show a significant economic impact on hospital resources. The additional robotic costs for the surgery were almost entirely offset by the cost savings during the postoperative hospital stay. However, these comparisons may differ when considering hybrid coronary revascularization with its additional percutaneous coronary intervention costs.

The association of timing of coronary artery bypass grafting for non-ST-elevation myocardial infarction and clinical outcomes in the contemporary United States

BACKGROUND

In contrast to the timing of coronary angiography and percutaneous coronary intervention, the optimal timing of coronary artery bypass grafting (CABG) in non-ST-elevation myocardial infarction (NSTEMI) has not been determined. Therefore, we compared in-hospital outcomes according to different time intervals to CABG surgery in a contemporary NSTEMI population in the USA.

METHODS

We identified all NSTEMI hospitalizations from 2016 to 2020 where revascularization was performed with CABG. We excluded NSTEMI with high-risk features using prespecified criteria. CABG was stratified into ≤24 h, 24-72 h, 72-120 h, and >120 h from admission. Outcomes of interest included in-hospital mortality, perioperative complications, length of stay (LOS), and hospital cost.

RESULTS

A total of 147 170 NSTEMI hospitalizations where CABG was performed were assessed. A greater percentage of females, Blacks, and Hispanics experienced delays to CABG surgery. No difference in in-hospital mortality was observed, but CABG at 72-120 h and at >120 h was associated with higher odds of non-home discharge and acute kidney injury compared with CABG at ≤24 h from admission. In addition to these differences, CABG at >120 h was associated with higher odds of gastrointestinal hemorrhage and need for blood transfusion. All 3 groups with CABG delayed >24 h had longer LOS and hospital-associated costs compared with hospitalizations where CABG was performed at ≤24 h.

CONCLUSION

CABG delays in patients with NSTEMI are more frequently experienced by women and minority populations and are associated with an increased burden of complications and healthcare cost.

Differences in Treatment Patterns and Outcomes of Acute Myocardial Infarction for Low- and High-Income Patients in 6 Countries

Importance

Differences in the organization and financing of health systems may produce more or less equitable outcomes for advantaged vs disadvantaged populations. We compared treatments and outcomes of older high- and low-income patients across 6 countries.

Objective

To determine whether treatment patterns and outcomes for patients presenting with acute myocardial infarction differ for low- vs high-income individuals across 6 countries.

Design, Setting, and Participants

Serial cross-sectional cohort study of all adults aged 66 years or older hospitalized with acute myocardial infarction from 2013 through 2018 in the US, Canada, England, the Netherlands, Taiwan, and Israel using population-representative administrative data.

Exposures

Being in the top and bottom quintile of income within and across countries.

Main Outcomes and Measures

Thirty-day and 1-year mortality; secondary outcomes included rates of cardiac catheterization and revascularization, length of stay, and readmission rates.

Results

We studied 289 376 patients hospitalized with ST-segment elevation myocardial infarction (STEMI) and 843 046 hospitalized with non-STEMI (NSTEMI). Adjusted 30-day mortality generally was 1 to 3 percentage points lower for high-income patients. For instance, 30-day mortality among patients admitted with STEMI in the Netherlands was 10.2% for those with high income vs 13.1% for those with low income (difference, -2.8 percentage points [95% CI, -4.1 to -1.5]). One-year mortality differences for STEMI were even larger than 30-day mortality, with the highest difference in Israel (16.2% vs 25.3%; difference, -9.1 percentage points [95% CI, -16.7 to -1.6]). In all countries, rates of cardiac catheterization and percutaneous coronary intervention were higher among high- vs low-income populations, with absolute differences ranging from 1 to 6 percentage points (eg, 73.6% vs 67.4%; difference, 6.1 percentage points [95% CI, 1.2 to 11.0] for percutaneous intervention in England for STEMI). Rates of coronary artery bypass graft surgery for patients with STEMI in low- vs high-income strata were similar but for NSTEMI were generally 1 to 2 percentage points higher among high-income patients (eg, 12.5% vs 11.0% in the US; difference, 1.5 percentage points [95% CI, 1.3 to 1.8 ]). Thirty-day readmission rates generally also were 1 to 3 percentage points lower and hospital length of stay generally was 0.2 to 0.5 days shorter for high-income patients.

Conclusions and Relevance

High-income individuals had substantially better survival and were more likely to receive lifesaving revascularization and had shorter hospital lengths of stay and fewer readmissions across almost all countries. Our results suggest that income-based disparities were present even in countries with universal health insurance and robust social safety net systems.

Cost-Effectiveness of Coronary Artery Bypass Grafting and Percutaneous Coronary Intervention in Patients With Chronic Kidney Disease and Acute Coronary Syndromes in the US Medicare Program

Background Coronary revascularization provides important long-term clinical benefits to patients with high-risk presentations of coronary artery disease, including those with chronic kidney disease. The cost-effectiveness of coronary interventions in this setting is not known. Methods and Results We developed a Markov cohort simulation model to assess the cost-effectiveness of percutaneous coronary intervention (PCI) and coronary artery bypass grafting (CABG) in patients with chronic kidney disease who were hospitalized with acute myocardial infarction or unstable angina. Model inputs were primarily drawn from a sample of 14 300 patients identified using the Medicare 20% sample. Survival, quality-adjusted life-years, costs, and cost-effectiveness were projected over a 20-year time horizon. Multivariable models indicated higher 30-day mortality and end-stage renal disease with both PCI and CABG, and higher stroke with CABG, relative to medical therapy. However, the model projected long-term gains of 0.72 quality-adjusted life-years (0.97 life-years) for PCI compared with medical therapy, and 0.93 quality-adjusted life-years (1.32 life-years) for CABG compared with PCI. Incorporation of long-term costs resulted in incremental cost-effectiveness ratios of $65 326 per quality-adjusted life-year gained for PCI versus medical therapy, and $101 565 for CABG versus PCI. Results were robust to changes in input parameters but strongly influenced by the background costs of the population, and the time horizon. Conclusions For patients with chronic kidney disease and high-risk coronary artery disease presentations, PCI and CABG were both associated with markedly increased costs as well as gains in quality-adjusted life expectancy, with incremental cost-effectiveness ratios indicating intermediate value in health economic terms.

Determinants of Value in Coronary Artery Bypass Grafting

Background Over 180 000 coronary artery bypass grafting (CABG) procedures are performed annually, accounting for $7 to $10 billion in episode expenditures. Assessing tradeoffs between spending and quality contributing to value during 90-day episodes has not been conducted but is essential for success in bundled reimbursement models. We, therefore, identified determinants of variability in hospital 90-day episode value for CABG. Methods Medicare and private payor admissions for isolated CABG from 2014 to 2016 were retrospectively linked to clinical registry data for 33 nonfederal hospitals in Michigan. Hospital composite risk-adjusted complication rates (≥1 National Quality Forum-endorsed, Society of Thoracic Surgeons measure: deep sternal wound infection, renal failure, prolonged ventilation >24 hours, stroke, re-exploration, and operative mortality) and 90-day risk-adjusted, price-standardized episode payments were used to categorize hospitals by value by defining the intersection between complications and spending. Results Among 2573 total patients, those at low- versus high-value hospitals had a higher percentage of prolonged length of stay >14 days (9.3% versus 2.4%, P=0.006), prolonged ventilation (17.6% versus 4.8%, P<0.001), and operative mortality (4.8% versus 0.6%, P=0.001). Mean total episode payments were $51 509 at low-compared with $45 526 at high-value hospitals (P<0.001), driven by higher readmission ($3675 versus $2177, P=0.005), professional ($7462 versus $6090, P<0.001), postacute care ($7315 versus $5947, P=0.031), and index hospitalization payments ($33 474 versus $30 800, P<0.001). Among patients not experiencing a complication or 30-day readmission (1923/2573, 74.7%), low-value hospitals had higher inpatient evaluation and management payments ($1405 versus $752, P<0.001) and higher utilization of inpatient rehabilitation (7% versus 2%, P<0.001), but lower utilization of home health (66% versus 73%, P=0.016) and emergency department services (13% versus 17%, P=0.034). Conclusions To succeed in emerging bundled reimbursement programs for CABG, hospitals and physicians should identify strategies to minimize complications while optimizing inpatient evaluation and management spending and use of inpatient rehabilitation, home health, and emergency department services.

Is the Use of BIMA in CABG Sub-Optimal? A Review of the Current Clinical and Economic Evidence Including Innovative Approaches to the Management of Mediastinitis

Bilateral internal mammary artery (BIMA) in coronary artery bypass grafting (CABG) has traditionally been limited. This review looks at the recent outcome data on BIMA in CABG focusing on the management of risk factors for mediastinitis, one of the potential barriers for more extensive BIMA utilization. A combination of pre-, intra- and postoperative strategies are essential to reduce mediastinitis. Limited data indicate that the incidence of mediastinitis can be reduced using closed incision negative-pressure wound therapy as a part of these strategies with the possibility of offering patients best treatment options by extending BIMA to those with a higher risk of mediastinitis. Recent economic data imply that the technology may challenge the current low uptake of BIMA by reducing the short-term cost differentials between single internal mammary artery and BIMA. Given that most published randomized controlled trials and meta-analyses of observational long-term outcome data favor BIMA, if short-term complications of BIMA including mediastinitis can be controlled adequately, there may be opportunities for more extensive use of BIMA leading to improved long-term outcomes. An ongoing study looking at BIMA in high-risk patients may provide evidence to support the hypothesis that mediastinitis should not be a factor in limiting the use of BIMA in CABG.

Minimally Invasive vs Open Coronary Surgery: A Multi-Institutional Analysis of Cost and Outcomes

BACKGROUND

Limited multi-institutional data evaluating minimally invasive cardiac surgery (MICS) coronary artery bypass surgery (CABG) outcomes have raised concern for increased resource utilization compared with standard sternotomy. The purpose of this study was to assess short-term outcomes and resource utilization with MICS CABG in a propensity-matched regional cohort.

METHODS

Isolated CABG patients (2012-2019) were extracted from a regional Society of Thoracic Surgeons database. Patients were stratified by MICS CABG vs open CABG via sternotomy, propensity-score matched 1:2 to balance baseline differences, and compared by univariate analysis.

RESULTS

Of 26,255 isolated coronary artery bypass graft patients, 139 MICS CABG and 278 open CABG patients were well balanced after matching. There was no difference in the operative mortality rate (2.2% open vs 0.7% MICS CABG, P = .383) or major morbidity (7.9% open vs 7.2% MICS CABG, P = .795). However, open CABG patients received more blood products (22.2% vs 12.2%, P = .013), and had longer intensive care unit (45 vs 30 hours, P = .049) as well as hospital lengths of stay (7 vs 6 days, P = .005). Finally, median hospital cost was significantly higher in the open CABG group ($35,011 vs $27,906, P < .001) compared with MICS CABG.

CONCLUSIONS

Open CABG via sternotomy and MICS CABG approaches are associated with similar, excellent perioperative outcomes. However, MICS CABG was associated with fewer transfusions, shorter length of stay, and ∼$7000 lower hospital cost, a superior resource utilization profile that improves patient care and lowers cost.

Coronary Artery Bypass Grafting in Cancer Patients: Prevalence and Outcomes in the United States

OBJECTIVE

To characterize the contemporary efficacy and utilization patterns of coronary artery bypass grafting (CABG) in specific cancer types.

METHODS

We leveraged the data from the National Inpatient Sample and plotted trends of utilization and outcomes of isolated CABG (with no other additional surgeries during the same hospitalization) procedures from January 1, 2003, through September 1, 2015. Propensity score matching was used to assess for potential differences in outcomes by type of cancer status among contemporary (2012-2015) patients.

RESULTS

Overall, the utilization of CABG decreased over time (250,677 in 2003 vs 134,534 in 2015, P<.001). However, the proportion of those with comorbid cancer increased (7.0% vs 12.6%, P<.001). Over time, in-hospital mortality associated with CABG use in cancer remained unchanged (.9% vs 1.0%, P=.72); yet, cancer patients saw an increase in associated major bleeding (4.5% vs 15.3%, P<.001) and rate of stroke (.9% vs 1.5%, P<.001) over time. In-hospital cost-of-care associated with CABG-use in cancer also increased over time ($29,963 vs $33,636, P<.001). When stratified by cancer types, in-hospital mortality was not higher in breast, lung, prostate, colon cancer, or lymphoma versus non-cancer CABG patients (all P>.05). However, there was a significantly higher prevalence of major bleeding but not stroke in patients with breast and prostate cancer only compared with non-cancer CABG patients (P<.01). Discharge dispositions were not found to be different between cancer sub-groups and non-cancer patients (P>.05), except for breast cancer patients who had lower home care, but higher skilled care disposition (P<.001).

CONCLUSION

Among those undergoing CABG, the prevalence of comorbid cancer has steadily increased. Outside of major bleeding, these patients appear to share similar outcomes to those without cancer indicating that CABG utilization should be not be declined in cancer patients when otherwise indicated. Further research into the factors underlying the decision to pursue CABG in specific cancer sub-groups is needed.

Cost-effectiveness of coronary artery bypass grafting plus mitral valve repair versus coronary artery bypass grafting alone for moderate ischemic mitral regurgitation

OBJECTIVE

The Cardiothoracic Surgical Trials Network reported that left ventricular reverse remodeling at 2 years did not differ between patients with moderate ischemic mitral regurgitation randomized to coronary artery bypass grafting plus mitral valve repair (n = 150) or coronary artery bypass grafting alone (n = 151). To address health resource use implications, we compared costs and quality-adjusted survival.

METHODS

We used individual patient data from the Cardiothoracic Surgical Trials Network trial on survival, hospitalizations, quality of life, and US hospitalization costs to estimate cumulative costs and quality-adjusted life years. A microsimulation model was developed to extrapolate to 10 years. Bootstrap and deterministic sensitivity analyses were performed to address uncertainty.

RESULTS

In-hospital costs were $59,745 for coronary artery bypass grafting plus mitral valve repair versus $51,326 for coronary artery bypass grafting alone (difference $8419; 95% uncertainty interval, 2259-18,757). Two-year costs were $81,263 versus $67,341 (difference 13,922 [2370 to 28,888]), and quality-adjusted life years were 1.35 versus 1.30 (difference 0.05; -0.04 to 0.14), resulting in an incremental cost-effectiveness ratio of $308,343/quality-adjusted life year for coronary artery bypass grafting plus mitral valve repair. At 10 years, its costs remained higher ($107,733 vs $88,583, difference 19,150 [-3866 to 56,826]) and quality-adjusted life years showed no difference (-0.92 to 0.87), with 5.08 versus 5.08. The likelihood that coronary artery bypass grafting plus mitral valve repair would be considered cost-effective at 10 years based on a cost-effectiveness threshold of $100K/quality-adjusted life year did not exceed 37%. Only when this procedure reduces the death rate by a relative 5% will the incremental cost-effectiveness ratio fall below $100K/quality-adjusted life year.

CONCLUSIONS

The addition of mitral valve repair to coronary artery bypass grafting for patients with moderate ischemic mitral regurgitation is unlikely to be cost-effective. Only if late mortality benefits can be demonstrated will it meet commonly used cost-effectiveness criteria.

Federal Payments for Coronary Revascularization Procedures Among Dual Enrollees in Medicare Advantage and the Veterans Affairs Health Care System

IMPORTANCE

More than 1 million US veterans are dually enrolled in a Medicare Advantage (MA) plan and in the Veterans Affairs (VA) health care system. The federal government prepays private MA plans to cover veterans; if a dually enrolled veteran receives an MA-covered service at the VA, the government is making 2 payments for the same service. It is not clear what proportion of veterans dually enrolled in VA and MA are undergoing coronary revascularization at VA vs non-VA hospitals.

OBJECTIVE

To describe where veterans who are enrolled in both VA and MA undergo coronary revascularization and the associated costs.

DESIGN, SETTINGS, AND PARTICIPANTS

This is a cohort study consisting of US veterans dually enrolled in VA and MA from January 1, 2010, to December 31, 2013, who had at least 1 VA encounter and underwent coronary revascularization during the study period. Data were analyzed from April 2019 to September 2019.

MAIN OUTCOMES AND MEASURES

Number of coronary artery bypass graft (CABG) operations and percutaneous coronary interventions (PCIs) performed through the VA and through MA during years 2010 to 2013, and the associated VA costs of coronary revascularization. In addition, multivariable logistic regression was performed to assess patient factors associated with receiving care through the VA.

RESULTS

A total of 18 874 VA users with concurrent MA enrollment who underwent coronary revascularization during 2010 to 2013 were identified (mean [SD] age, 75.3 [8.8] years; 18 739 men [99.0%]). Enrollees were predominantly white (17 457 patients [92.0%]). Among patients, 4115 (22.0%) underwent either CABG or PCI through the VA only, 14 281 (75.0%) did so through MA only, and 478 (2.5%) underwent coronary revascularization procedures through both payers. From 2010 to 2013, these veterans underwent 4764 coronary revascularization procedures (721 CABGs and 3043 PCIs) that cost the VA $214.7 million ($115.8 million for CABGs and $99.0 million for PCIs). In multivariable analysis, nonwhite patients were more likely than white patients to undergo coronary revascularization through the VA (odds ratio, 1.73; 95% CI, 1.52-1.96; P < .001), and for each year of age, veterans were less likely to undergo coronary revascularization through the VA (odds ratio, 0.95; 95% CI, 0.94-0.95; P < .001). There was no statistically significant association between undergoing coronary vascularization through the VA and distance in miles to the nearest VA hospital (odds ratio, 1.00; 95% CI, 0.99-1.00; P = .30).

CONCLUSIONS AND RELEVANCE

A substantial share of VA users concurrently enrolled in an MA plan underwent coronary revascularization procedures through the VA, incurring significant duplicative federal health care spending. Given the financial pressures facing both Medicare and the VA, government officials should consider policy solutions to mitigate redundant spending.

Variation in expenditure for common, high cost surgical procedures in a working age population: implications for reimbursement reform

BACKGROUND

In the move toward value-based care, bundled payments are believed to reduce waste and improve coordination. Some commercial insurers have addressed this through the use of bundled payment, the provision of one fee for all care associated with a given index procedure. This system was pioneered by Medicare, using a population generally over 65 years of age, and despite its adoption by mainstream insurers, little is known of bundled payments' ability to reduce variation or cost in a working-age population. This study uses a universally-insured, nationally-representative population of adults aged 18-65 to examine the effect of bundled payments for five high-cost surgical procedures which are known to vary widely in Medicare reimbursement: hip replacement, knee replacement, coronary artery bypass grafting (CABG), lumbar spinal fusion, and colectomy.

METHODS

Five procedures conducted on adults aged 18-65 were identified from the TRICARE database from 2011 to 2014. A 90-day period from index procedure was used to determine episodes of associated post-acute care. Data was sorted by Zip code into hospital referral regions (HRR). Payments were determined from TRICARE reimbursement records, they were subsequently price standardized and adjusted for patient and surgical characteristics. Variation was assessed by stratifying the HRR into quintiles by spending for each index procedure.

RESULTS

After adjusting for case mix, significant inter-quintile variation was observed for all procedures, with knee replacement showing the greatest variation in both index surgery (107%) and total cost of care (75%). Readmission was a driver of variation for colectomy and CABG, with absolute cost variation of $17,257 and $13,289 respectively. Other post-acute care spending was low overall (≤$1606, for CABG).

CONCLUSIONS

This study demonstrates significant regional variation in total spending for these procedures, but much lower spending for post-acute care than previously demonstrated by similar procedures in Medicare. Targeting post-acute care spending, a common approach taken by providers in bundled payment arrangements with Medicare, may be less fruitful in working aged populations.

Who Will be the Costliest Patients? Using Recent Claims to Predict Expensive Surgical Episodes

INTRODUCTION

Surgery accounts for almost half of inpatient spending, much of which is concentrated in a subset of high-cost patients. To study the effects of surgeon and hospital characteristics on surgical expenditures, a way to adjust for patient characteristics is essential.

DESIGN

Using 100% Medicare claims data, we identified patients aged 66-99 undergoing elective inpatient surgery (coronary artery bypass grafting, colectomy, and total hip/knee replacement) in 2014. We calculated price-standardized Medicare payments for the surgical episode from admission through 30 days after discharge (episode payments). On the basis of predictor variables from 2013, that is, Elixhauser comorbidities, hierarchical condition categories, Medicare's Chronic Conditions Warehouse (CCW), and total spending, we constructed models to predict the costs of surgical episodes in 2014.

RESULTS

All sources of comorbidity data performed well in predicting the costliest cases (Spearman correlation 0.86-0.98). Models on the basis of hierarchical condition categories had slightly superior performance. The costliest quintile of patients as predicted by the model captured 35%-45% of the patients in each procedure's actual costliest quintile. For example, in hip replacement, 44% of the costliest quintile was predicted by the model's costliest quintile.

CONCLUSIONS

A significant proportion of surgical spending can be predicted using patient factors on the basis of readily available claims data. By adjusting for patient factors, this will facilitate future research on unwarranted variation in episode payments driven by surgeons, hospitals, or other market forces.

Factors associated with switching between low and super utilization in the surgical population: A study in medicare expenditure

BACKGROUND

Considered the top 5% of healthcare utilizers, "super-utilizers" are estimated to consume as much as 40-55% of all healthcare costs. The aim of this study was to identify factors associated with switching between low- and super-utilization.

METHODS

Low and super-utilizers who underwent abdominal aortic aneurysm (AAA) repair, coronary artery bypass graft (CABG), colectomy, total hip arthroplasty (THA), total knee arthroplasty (TKA), or lung resection between 2013 and 2015 were identified from 100% Medicare Inpatient Standard Analytic Files.

RESULTS

Among 1,049,160 patients, 788,488 (75.1%) and 21,700 (2.1%) patients were low- or super-utilizers prior to surgery, respectively. Among patients who were super-utilizers before surgery, 23% remained super-utilizers post-operatively, yet 26.8% patients became low-utilizers after surgery. Factors associated with moving from low-to super-utilization in the pre-versus post-operative setting included AAA repair, higher Charlson, and pulmonary failure. In contrast, pre-operative super-utilizers who became low-utilizers in the post-operative setting were less likely to be African American or have undergone CABG.

CONCLUSION

While 3% of pre-operative low-utilizers became super-utilizers likely due to complications, nearly one quarter of all pre-operative super-utilizers became low-utilizers following surgery suggesting success of the surgery to resolve underlying conditions associated with preoperative super-utilization.

Five-year costs from a randomised comparison of bilateral and single internal thoracic artery grafts

BACKGROUND

The use of bilateral internal thoracic arteries (BITA) for coronary artery bypass grafting (CABG) may improve survival compared with CABG using single internal thoracic arteries (SITA). We assessed the long-term costs of BITA compared with SITA.

METHODS

Between June 2004 and December 2007, 3102 patients from 28 hospitals in seven countries were randomised to CABG surgery using BITA (n=1548) or SITA (n=1554). Detailed resource use data were collected from the initial hospital episode and annually up to 5 years. The associated costs of this resource use were assessed from a UK perspective with 5 year totals calculated for each trial arm and pre-selected patient subgroups.

RESULTS

Total costs increased by approximately £1000 annually in each arm, with no significant annual difference between trial arms. Cumulative costs per patient at 5-year follow-up remained significantly higher in the BITA group (£18 629) compared with the SITA group (£17 480; mean cost difference £1149, 95% CI £330 to £1968, p=0.006) due to the higher costs of the initial procedure. There were no significant differences between the trial arms in the cost associated with healthcare contacts, medication use or serious adverse events.

CONCLUSIONS

Higher index costs for BITA were still present at 5-year follow-up mainly driven by the higher initial cost with no subsequent difference emerging between 1 year and 5 years of follow-up. The overall cost-effectiveness of the two procedures, to be assessed at the primary endpoint of the 10-year follow-up, will depend on composite differences in costs and quality-adjusted survival.

TRIAL REGISTRATION NUMBER

ISRCTN46552265.

The Real-World Cost-Effectiveness of Coronary Artery Bypass Surgery Versus Stenting in High-Risk Patients: Propensity Score-Matched Analysis of a Single-Centre Experience

BACKGROUND

There are limited economic evaluations comparing coronary artery bypass grafting (CABG) and percutaneous coronary intervention (PCI) for multi-vessel coronary artery disease (MVCAD) in contemporary, routine clinical practice.

OBJECTIVE

The aim was to perform a cost-effectiveness analysis comparing CABG and PCI in patients with MVCAD, from the perspective of the Australian public hospital payer, using observational data sources.

METHODS

Clinical data from the Melbourne Interventional Group (MIG) and the Australian and New Zealand Society of Cardiac and Thoracic Surgeons (ANZSCTS) registries were analysed for 1022 CABG (treatment) and 978 PCI (comparator) procedures performed between June 2009 and December 2013. Clinical records were linked to same-hospital admissions and national death index (NDI) data. The incremental cost-effectiveness ratios (ICERs) per major adverse cardiac and cerebrovascular event (MACCE) avoided were evaluated. The propensity score bin bootstrap (PSBB) approach was used to validate base-case results.

RESULTS

At mean follow-up of 2.7 years, CABG compared with PCI was associated with increased costs and greater all-cause mortality, but a significantly lower rate of MACCE. An ICER of $55,255 (Australian dollars)/MACCE avoided was observed for the overall cohort. The ICER varied across comparisons against bare metal stents (ICER $25,815/MACCE avoided), all drug-eluting stents (DES) ($56,861), second-generation DES ($42,925), and third-generation of DES ($88,535). Moderate-to-low ICERs were apparent for high-risk subgroups, including those with chronic kidney disease ($62,299), diabetes ($42,819), history of myocardial infarction ($30,431), left main coronary artery disease ($38,864), and heart failure ($36,966).

CONCLUSIONS

At early follow-up, high-risk subgroups had lower ICERs than the overall cohort when CABG was compared with PCI. A personalised, multidisciplinary approach to treatment of patients may enhance cost containment, as well as improving clinical outcomes following revascularisation strategies.

Drivers of Payment Variation in 90-Day Coronary Artery Bypass Grafting Episodes

Importance

Coronary artery bypass grafting (CABG) is scheduled to become a mandatory Medicare bundled payment program in January 2018. A contemporary understanding of 90-day CABG episode payments and their drivers is necessary to inform health policy, hospital strategy, and clinical quality improvement activities. Furthermore, insight into current CABG payments and their variation is important for understanding the potential effects of bundled payment models in cardiac care.

Objective

To examine CABG payment variation and its drivers.

Design, Setting, and Participants

This retrospective cohort study used Medicare and private payer claims to identify patients who underwent nonemergent CABG surgery from January 1, 2012, through October 31, 2015. Ninety-day price-standardized, risk-adjusted, total episode payments were calculated for each patient, and hospitals were divided into quartiles based on the mean total episode payments of their patients. Payments were then subdivided into 4 components (index hospitalization, professional, postacute care, and readmission payments) and compared across hospital quartiles. Seventy-six hospitals in Michigan representing a diverse set of geographies and practice environments were included.

Main Outcomes and Measures

Ninety-day CABG episode payments.

Results

A total of 5910 patients undergoing nonemergent CABG surgery were identified at 33 of the 76 hospitals; of these, 4344 (73.5%) were men and mean (SD) age was 68.0 (9.3) years. At the patient level, risk-adjusted, 90-day total episode payments for CABG varied from $11 723 to $356 850. At the hospital level, the highest payment quartile of hospitals had a mean total episode payment of $54 399 compared with $45 487 for the lowest payment quartile (16.4% difference, P < .001). The highest payment quartile hospitals compared with the lowest payment quartile hospitals had 14.6% higher index hospitalization payments ($34 992 vs $30 531, P < .001), 33.9% higher professional payments ($8060 vs $6021, P < .001), 29.6% higher postacute care payments ($7663 vs $5912, P < .001), and 35.1% higher readmission payments ($3576 vs $2646, P = .06). The drivers of this variation are diagnosis related group distribution, increased inpatient evaluation and management services, higher utilization of inpatient rehabilitation, and patients with multiple readmissions.

Conclusions and Relevance

Wide variation exists in 90-day CABG episode payments for Medicare and private payer patients in Michigan. Hospitals and clinicians entering bundled payment programs for CABG should work to understand local sources of variation, with a focus on patients with multiple readmissions, inpatient evaluation and management services, and postdischarge outpatient rehabilitation care.

Economies of scale: body mass index and costs of cardiac surgery in Ontario, Canada

An obesity paradox has been described, whereby obese patients have better health outcomes than normal weight patients in certain clinical situations, including cardiac surgery. However, the relationship between body mass index (BMI) and resource utilization and costs in patients undergoing coronary artery bypass graft (CABG) surgery is largely unknown. We examined resource utilization and cost data for 53,224 patients undergoing CABG in Ontario, Canada over a 10-year period between 2002 and 2011. Data for costs during hospital admission and for a 1-year follow-up period were derived from the Institute for Clinical Evaluative Sciences, and analyzed according to pre-defined BMI categories using analysis of variance and multivariate models. BMI independently influenced healthcare costs. Underweight patients had the highest per patient costs ($50,124 ± $36,495), with the next highest costs incurred by morbidly obese ($43,770 ± $31,747) and normal weight patients ($42,564 ± $30,630). Obese and overweight patients had the lowest per patient costs ($40,760 ± $30,664 and $39,960 ± $25,422, respectively). Conversely, at the population level, overweight and obese patients were responsible for the highest total yearly population costs to the healthcare system ($92 million and $50 million, respectively, compared to $4.2 million for underweight patients). This is most likely due to the high proportion of CABG patients falling into the overweight and obese BMI groups. In the future, preoperative risk stratification and preparation based on BMI may assist in reducing surgical costs, and may inform health policy measures aimed at the management of weight extremes in the population.