Volume of frail patients predicts outcome in frail patients after cardiac surgery.

OBJECTIVE: Recent data from major noncardiac surgery suggest that outcomes in frail patients are better predicted by a hospital's volume of frail patients specifically, rather than overall surgical volume. We sought to evaluate this "frailty volume-frailty outcome relationship" in patients undergoing cardiac surgery. METHODS: We studied 72,818 frail patients undergoing coronary artery bypass grafting or valve replacement surgery from 2010 to 2014 using the Nationwide Readmissions Database. Frailty was defined using the Johns Hopkins Adjusted Clinical Groups frailty-defining diagnoses indicator. Multilevel logistic regression was used to assess the independent effect of frailty volume by quartile on mortality, surgical complications, failure to rescue, nonhome discharge, 30-day readmissions, length of stay, and hospital costs in frail patients. RESULTS: In comparing the highest volume quartiles with the lowest, both overall cardiac surgical volume and volume for frail patients were significantly associated with shorter length of stay and reduced costs. However, frailty volume was also independently associated with significantly reduced in-hospital mortality (odds ratio, 0.79; 95% confidence interval, 0.67-0.94; P = .006) and failure to rescue (odds ratio, 0.83; 95% confidence interval, 0.70-0.98; P = .03), whereas no such association was seen between overall volume and either mortality (odds ratio, 0.94; 95% confidence interval, 0.74-1.10; P = .43) or failure to rescue (odds ratio, 0.98; 95% confidence interval, 0.83-1.17; P = .85). Neither frailty volume nor overall volume showed any significant relationship with the rate of 30-day readmissions. CONCLUSIONS: In frail patients undergoing cardiac surgery, surgical volume of frail patients was a significant independent of predictor of in-hospital mortality and failure to rescue, whereas overall surgical volume was not. Thus, the "frailty volume-outcome relationship" superseded the traditional "volume-outcome relationship" in frail patients with cardiac disease.

The impact of surgeon and hospital procedural volume on outcomes after aortic root replacement in the United States.

OBJECTIVE: Surgeon procedural volume for complex cardiac procedures have become important quality metrics. The objective is to determine the association of surgeon and hospital case volume on patient outcomes after an aortic root replacement for aortic root aneurysms. METHODS: From 2009 to 2014, 4629 Medicare patients underwent an aortic root replacement for a root aneurysm. Procedures were performed by 1276 surgeons at 718 hospitals. Patients with endocarditis, aortic rupture, or Type-A dissection were excluded. Procedural volume was defined as mean number of cases performed each year during the study period. The impact of hospital and surgeon volume on adjusted 30-day mortality was analyzed as a continuous variable using adjusted logistic regression with cubic splines. RESULTS: After an aortic root replacement, we observed a nonlinear reduction in the adjusted odds ratio for 30-day mortality as surgeon and hospital volume increased. Surgeons that performed approximately five cases/year and hospitals that completed approximately five cases/year had the greatest reduction in the odds of perioperative death. Patients treated at high-volume hospitals (≥4.5 cases/year) had a lower risk for 30-day postoperative stroke (hazard ratio [HR] = 0.51, p = .008), myocardial infarction (HR = 0.49, p = .016), hemodialysis (HR = 0.44, p = .005), and reoperation (HR = 0.48, p = .003). Additionally, patients treated with high-volume surgeons (≥9 cases/year) had lower risk for stroke (HR = 0.65, p = .005), hemodialysis (HR = 0.65, p = .03), sepsis (HR = 0.62, p = .03), and reoperation (HR = 0.67, p = .004). CONCLUSION: Among Medicare patients undergoing an aortic root replacement, there is a strong inverse relationship between annualized surgeon and hospital case volume and postoperative outcomes. Procedural volume is an important quality metric for this high-risk procedure.

Thoracic Endovascular Aneurysm Repair Trends and Outcomes in Over 27,000 Medicare Patients for Descending Thoracic Aneurysms.

BACKGROUND: Since United States Food and Drug Administration approval in 2005, thoracic endovascular aneurysm repair (TEVAR) has replaced open surgery to become the preferred treatment for descending thoracic aneurysms (DTAs). This study investigated TEVAR trends during the previous 15 years regarding patient and hospital characteristics and their effect on survival. METHODS: Between 2000 and 2014, 27,079 Medicare patients underwent TEVAR for DTA. We analyzed TEVAR trends during this period and stratified hospitals based on the number of cases completed during the previous 5 years: low (0-19 cases), medium (20-99 cases), and high (≥100 cases) volume. Trends over time were calculated using Poisson regression to determine the average annual percentage changes (aAPC). Survival was calculated using a multivariate Cox regression and adjusted logistic regression with a restricted cubic spline. RESULTS: TEVAR volume significantly increased from 81 cases in 2000 to 3478 cases in 2014 (aAPC, 16.2%; P < .001). During the study period, the proportion of cases performed at medium-volume centers increased (aAPC, 5.2%; P < .001). Thirty-day mortality after TEVAR increased in the recent period (2013-2014) to 8.8% as compared with 6.6% in the early years (2004-2006) of TEVAR (P < .001), and a significant contribution was due to increased patient comorbidity score (aAPC, 1.6%; P < .001). Lastly, TEVAR center volume was significantly associated with 30-day survival when fewer than 33 cases were done in the prior 5 years. CONCLUSIONS: From 2000 to 2014, TEVAR volume accelerated, and centers are gaining more experience. TEVAR patients have become more acute, and mortality has increased over this period. Patient selection and procedural experience are critical to improving outcomes.

Outcomes after thoracic endovascular aortic repair in patients with chronic kidney disease in the Medicare population.

OBJECTIVE: Thoracic endovascular aortic repair has been increasingly performed in higher-risk patients with renal failure. The objective was to compare Medicare patients with preoperative chronic kidney disease with patients with normal renal function to determine differences in postoperative survival and complications. METHODS: From 2000 to 2014, 27,079 Medicare fee-for service patients underwent thoracic endovascular aortic repair. Patients were stratified by kidney function, and 23,375 patients (86%) had no chronic kidney disease, 2957 patients (11%) had chronic kidney disease stage I/IV, and 747 patients (3%) had end-stage renal disease or hemodialysis. Groups were then compared with determined differences in adjusted all-cause mortality and rates of postoperative complications. RESULTS: Overall survival was significantly worse among patients with chronic kidney disease and end-stage renal disease or hemodialysis compared with patients with no chronic kidney disease (1-year survival no chronic kidney disease: 78%; chronic kidney disease I/II: 77%; chronic kidney disease III: 67%; chronic kidney disease IV: 58%; and end-stage renal disease or hemodialysis: 48%, P < .001). Mortality was significantly increased among patients with chronic kidney disease III (hazard ratio [HR], 1.29; P < .001), chronic kidney disease IV (HR, 1.74; P < .001), and end-stage renal disease or hemodialysis (HR, 2.03; P < .001). No mortality difference was found between patients with no chronic kidney disease and patients with chronic kidney disease stage I/II. At 30 days after thoracic endovascular aortic repair, sepsis was increased for patients with chronic kidney disease stage III/IV (HR, 1.7; P < .001) and end-stage renal disease or hemodialysis (HR, 2.7; P < .001). CONCLUSIONS: In this elderly Medicare population undergoing thoracic endovascular aortic repair, patients with chronic kidney disease stage III, chronic kidney disease stage IV, or end-stage renal disease/hemodialysis had poor survival and increased morbidity compared with those with normal kidney function. These data may suggest that patients with chronic kidney disease stage III, chronic kidney disease stage IV, or end-stage renal disease/hemodialysis should be more cautiously evaluated for thoracic endovascular aortic repair, weighing the benefits of the procedure against the high expected mortality.

Causes, Risk Factors, and Costs of 30-Day Readmissions After Mitral Valve Repair and Replacement.

BACKGROUND: Postsurgical readmissions are an increasingly scrutinized marker of health care quality. We sought to estimate the risk factors and costs associated with readmissions after mitral valve (MV) surgery in a large, nationally representative cohort. METHODS: Adult patients undergoing MV repair or replacement were queried from the National Readmissions Database from 2010 to 2014. Data were collected on the prevalence and indications for readmission within 30 days as well as the hospital-, procedure, and patient-level risk factors as determined by multivariable logistic regression. RESULTS: Among 76,342 patients undergoing MV surgery, the rate of 30-day readmission was 17.0%. Those undergoing replacement procedures had significantly higher readmission rates (20.7% vs 13.1%; P < .001) compared with repair. Significant independent predictors of readmission after both MV repair and replacement included length of stay ≥8 days, chronic lung disease, chronic renal disease, and low hospital procedural volume for MV surgery. Readmissions to nonindex hospitals accounted for 26.6% of all readmissions. The most common indications for readmission were heart failure (21.4%), arrhythmia (17.0%) and respiratory diagnoses (15.0%), and infections (10.2%). The mean cost per readmission was $15,397, and among readmitted patients, the cost of readmission accounted for 17.8% of the total cost of the episode of care. CONCLUSIONS: Nearly 1 in 5 patients undergoing MV surgery are readmitted within 30 days. Treatment at a low-volume center was strongly associated with readmission, and much of the readmission burden falls on nonindex hospitals. Further characterization of readmissions may improve the quality of care associated with MV surgery.

Geographically Derived Socioeconomic Factors to Improve Risk Prediction in Patients Having Aortic Valve Replacement.

Socioeconomic status (SES) has been associated with adverse outcomes after cardiac surgery, but is not included in commonly applied risk adjustment models. This study evaluates whether inclusion of SES improves aortic valve replacement (AVR) risk prediction models, as this is the most common elective operation performed at our institution during the study period. All patients who underwent AVR at a single institution from 2005 to 2015 were evaluated. SES measures included unemployment, poverty, household income, home value, educational attainment, housing density, and a validated SES index score. The risk scores for mortality, complications, and increased length of stay were generated using models published by the Society for Thoracic Surgeons. Univariate models were fitted for each SES covariate and multivariable models for mortality, any complication, and prolonged length of stay (PLOS). A total of 1,386 patients underwent AVR with a 2.7% mortality, 15.1% complication rate, and 9.7% PLOS. In univariate models, higher education was associated with decreased mortality (odds ratio [OR] 0.96, p = 0.04) and complications (OR 0.97, p <0.01). Poverty was associated with increased length of stay (OR 1.02, p = 0.02). In the multivariable models, the inclusion of SES covariates increased the area under the curve for mortality (0.735 to 0.750, p = 0.14), for any complications (0.663 to 0.680, p <0.01), and for PLOS (0.749 to 0.751, p = 0.12). The inclusion of census-tract-level socioeconomic factors into the the Society of Thoracic Surgeons risk predication models is new and shows potential to improve risk prediction for outcomes after cardiac surgery. With the possibility of reimbursement and institutional ranking based on these outcomes, this study represents an improvement in risk prediction model.

Cost and contribution margin of transcatheter versus surgical aortic valve replacement.

OBJECTIVE: To compare the cost of and payments for transcatheter aortic valve replacement (TAVR), a novel and expensive technology, and surgical aortic valve replacement (SAVR). METHODS: Medicare claims provided hospital charges, payments, and outcomes between January and December 2012. Hospital costs and charges were estimated using hospital-specific cost-to-charge ratios. Costs and payments were examined in propensity score- matched TAVR and SAVR patients. RESULTS: Medicare spent $215,770,200 nationally on 4083 patients who underwent TAVR in 2012. Hospital costs were higher for TAVR patients (median, $50,200; interquartile range [IQR], $39,800-$64,300) than for propensity-matched SAVR patients ($45,500; IQR, $34,500-$63,300; P < .01), owing largely to higher estimated medical supply costs, including the implanted valve prosthesis. Postprocedure hospital length of stay (LOS) length was shorter for TAVR patients (median, 5 days [IQR, 4-8 days] vs 7 days [IQR, 5-9 days]; P < .01), as was total intensive care unit (ICU) LOS (median, 2 days [IQR, 0-5 days] vs 3 days [IQR, 1-6 days]; P < .01). Medicare payments were lower for TAVR hospitalizations (median, $49,500; IQR, $36,900-$64,600) than for SAVR (median, $50,400; IQR, $37,400-$65,800; P < .01). The median of the differences between payments and costs (contribution margin) was -$3380 for TAVR hospitalizations and $2390 for SAVR hospitalizations (P < .01). CONCLUSIONS: TAVR accounted for $215 million in Medicare payments in its first year of clinical use. Among SAVR Medicare patients at a similar risk level, TAVR was associated with higher hospital costs despite shorter ICU LOS and hospital LOS. Overall and/or medical device cost reductions are needed for TAVR to have a net neutral financial impact on hospitals.

Too high for transplantation? Single-center analysis of the lung allocation score.

BACKGROUND: Recent studies using United Network for Organ Sharing data suggest that lung transplantation in patients with high lung allocation scores (LAS) may lead to organ and resource wastage. Therefore, to determine whether a LAS cutoff value should be considered, we evaluated the relation of LAS to waitlist and posttransplant mortality in our center to determine if it could identify patients for whom listing for transplantation may be futile. METHODS: From May 1, 2005 to July 1, 2010, 537 adults were listed and 426 underwent primary lung transplantation at our institution. Endpoints were mortality before and after lung transplantation. The relationships of LAS at listing to waitlist mortality and of pretransplant LAS to posttransplant mortality were both analyzed by multiphase hazard function methodology. RESULTS: Higher LAS was strongly associated with waitlist mortality (p<0.0001), with the highest quartile (LAS ranging from 47 to 95) experiencing 75% mortality within a year of listing. Although early (p=0.05), but not late (p=0.4), posttransplant survival was associated with higher LAS at transplantation, once other clinical characteristics predictive of early mortality were accounted for, neither waitlist nor pretransplant LAS was independently related to posttransplant mortality (p=0.12). CONCLUSIONS: Higher LAS strongly predicts higher mortality on the lung transplantation waitlist, underscoring the value of LAS in prioritizing patients with the highest scores for transplantation. Early posttransplant mortality is modestly higher with higher pretransplant LAS, but the data of our center do not suggest a value above which transplantation should be denied as futile. This suggests that donor organs and resources are not being wasted.