Volume-Outcome Relationship in Surgical and Cardiac Transcatheter Interventions with a Focus on Transcatheter Aortic Valve Implantation

“Practice makes perfect” is an old saying that can be true for complex interventions. There is a strong and persistent relationship between high volume and better outcomes with more than 300 studies being reported on the subject. The more complex the procedure, the greater the volume-outcome relationship is. Failure to rescue was shown to be one of the factors explaining higher mortality rates post complex surgery. High-volume centers provide a better safety net, thanks to the structure and better protocols, and low-volume operators have better results at high-volume centers than at low-volume centers. Finally, effort should be made to regroup complex procedures in high-volume centers, but without compromising patient access to the procedures. Adaptation to local and geographic constraints is important.

Comparing Trajectory of Surgical Aortic Valve Replacement in the Early vs. Late Transcatheter Aortic Valve Replacement Era

Background: Traditionally, the only effective treatment for aortic stenosis was surgical aortic valve replacement (SAVR). Transcatheter aortic valve replacement (TAVR) was approved in the United States in late 2011 and provided a critical alternative therapy. Our aims were to investigate the trends in the utilization of SAVR in the early vs. late TAVR era and to assess SAVR and TAVR outcomes. Methods: Using the 2011-2017 National Inpatient Sample database, we identified hospitalizations for patients with a most responsible diagnosis of aortic stenosis during which an aortic valve replacement (AVR) was performed, either SAVR or TAVR. Patients' sociodemographic and clinical characteristics, procedure complications, length of stay, and mortality were analyzed. Multivariable analyses were performed to identify predictors of in-hospital mortality. Piecewise regression analyses were performed to assess temporal trends in SAVR and TAVR utilization. Results: A total of 542,734 AVR procedures were analyzed. The utilization of SAVR was steady until 2014 with a significant downward trend in the following years 2015-2017 (P = 0.026). In contrast, a steady upward trend was observed in the TAVR procedure with a significant increase during the years 2015-2017 (P = 0.006). Higher in-hospital mortality was observed in SAVR patients. The mortality rate declined from 2011 to 2017 in a significantly higher proportion in the TAVR compared with the SAVR group. Conclusion: Utilization of SAVR showed a downward trend during the late TAVR era (2015-2017), and TAVR utilization demonstrated a steady upward trend during the years 2011-2017. Higher in-hospital mortality was recorded in patients who underwent SAVR.

The Relation between Volume and Outcome of Transcatheter and Surgical Aortic Valve Replacement: A Systematic Review and Meta-Analysis

Transcatheter aortic valve replacement (TAVR) and surgical aortic valve replacement (SAVR) are standard procedures for dealing with severe aortic stenosis patients. Researchers have not carried out a systematic review of the volume-outcome relationship in TAVR and SAVR. Our study is intended to address this problem. We systemically searched databases through MEDLINE, EMBASE, PUBMED, and the Cochrane Library up to September 2019. Two reviewers independently screened for the studies and evaluated bias. We used short-term mortality (in-hospital or 30-day mortality) as an outcome. A meta-analysis of TAVR with 115,596 patients ranging from 2005 to 2016 showed a result significantly in favor of high-volume hospitals (OR 0.43 (CI 0.36-0.51)). The subgroup of population period, region, data type, and cut-off value did not show any difference. A meta-analysis of SAVR comprising 418,384 patients ranging from 1994 to 2011 revealed that the OR of short-term mortality for a high-volume hospital compared with that of a low-volume hospital was 0.73 (CI 0.71, 0.74). No difference was observed in subgroups based on population period and cut-off. In conclusion, we found that short-term mortality was lower in high-volume hospitals for both TAVR and SAVR.

Operational and Institutional Recommendations and Requirements for TAVR: A Review of Expert Consensus and the Impact on Health Care Policy

When transcatheter aortic valve replacement (TAVR) was first approved for use in the United States in 2012, multiple leading surgical and cardiology societies were tasked with creating recommendations and requirements for operators and institutions starting and maintaining TAVR programs. Creation of this consensus document was challenging due to limited experience with this new technology, and a lack of robust centralized data that could be used to validate outcome measures and create benchmarks for self-assessment and improvement. Despite these limitations, this document provided government agencies a framework for regulation that ultimately determined requirements for Medicare payment for TAVR and therefore greatly determined how and where care was delivered for patients with aortic stenosis. After the proliferation of TAVR institutions throughout the US and with data from more than 100,000 cases in the STS/ACC Transcatheter Valve Therapies TM Registry, leaders of the same societies reconvened in 2018 to update their consensus document. The new recommendations include suggested personnel, facilities, training, and assessment of outcomes and competencies required to run a safe and efficient TAVR program. This article seeks to detail the changes from the original consensus document with a particular focus on issues relevant to cardiac anesthesiologists as well as important healthcare policy ramifications for patients and providers in the United States.

Comparison of Frequency of Late Gastrointestinal Bleeding With Transcatheter Versus Surgical Aortic Valve Replacement

Improvements in technology and operator experience have led to exponential growth of transcatheter aortic valve implantation (TAVI) programs. Late bleeding complications were recently highlighted after TAVI with a high impact on morbidity. The purpose of the present study was to assess the incidence and financial impact of late Gastrointestinal (GI) bleeding after TAVI, and compare with the surgical cohort. Retrospective analysis of the National Readmissions Database was performed from January 2011 to December 2014, and patients who underwent TAVI or surgical aortic valve replacement (SAVR) were identified. Incidence of readmission with a diagnosis of GI bleeding was utilized as the primary end point. Overall, 43,357 patients were identified who underwent TAVI, whereas 310,013 patients underwent SAVR. Compared with SAVR, TAVI patients were older (81 vs 68y, p < 0.001), more women (48% vs 36%, p < 0.001), and had higher Elixhauser Comorbidity Index (6 vs 5, p < 0.001). Hospital stay was shorter with TAVI (5 vs 8 days, p < 0.001), but raw in-hospital mortality rates were similar (4.2% vs 3.8%, p = 0.022). In the TAVI cohort, 3.3% of patients were rehospitalized for GI bleeding compared with 1.5% of the SAVR cohort (p < 0.001). Average time to bleeding readmission was similar between cohorts (92 vs 84 days, p = 0.049). After multivariable adjustment, TAVI remained significantly associated with readmissions for GI bleeding compared with SAVR Adjusted Odds Ratio (AOR 1.54 [1.38 to 1.71], p < 0.001). In this national cohort study, TAVI was associated with more frequent readmissions for late GI bleeding compared with SAVR. In conclusion, strategies to reduce late GI bleeding may serve as important targets for improvement in overall quality of care.

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.

Volume-outcome relationships for transcatheter aortic valve replacement-risk-adjusted and volume stratified analysis of TAVR outcomes

Objectives

This purpose of the study was to evaluate TAVR outcomes at low, intermediate and high volume institutions.

Background

For the care of complex patients, volume-outcome effect is well described. The initial US TAVR experience was limited to a few centers of excellence. The impact of institutional volume on outcomes after TAVR has not been systematically studied.

Methods

Within the Banner Health system, TAVR is performed at 3 institutions-a low volume, an intermediate volume and a high volume institution. 181 consecutive patients undergoing TAVR within these 3 institutions were the study cohort. To adjust for bias and confounders between the 3 groups, risk-adjusted multivariate logistic regression and propensity score analysis was performed. The primary endpoint was a composite of mortality, dialysis-dependent renal failure, cerebrovascular accident, need for new permanent pacemaker and readmission within 30 days.

Results

The primary endpoint was reached in 38.8% of patients at the high volume institution and 76.2% of patients at the low volume institution (p < 0.01). Having a TAVR procedure at a larger volume institution was an independent predictor of having improved outcomes (OR 0.33, 95% CI 0.16–0.68; p = 0.003). These improved outcomes after the TAVR procedure noted at the large volume institution were seen in the most complex patients: age ≥80 years, BMI >30, diabetes, hypertension, prior CAD, CKD and NYHA class III/IV heart failure.

Conclusions

High-risk patients undergoing TAVR at a large volume institution have better 30-day outcomes compared to outcomes at intermediate and low volume centers.

Learning Curves Among All Patients Undergoing Transcatheter Aortic Valve Implantation in Germany: A Retrospective Observational Study

BACKGROUND

Transcatheter aortic valve implantation (TAVI) is a rapidly evolving technique for therapy of aortic stenosis. Previous studies report learning curves with respect to in-hospital mortality and clinical complications. We aim to determine whether observed improvements of in-hospital outcomes after TAVI are the result of improvements in procedures or due to a change in the patient population, and whether improvements differ between the transfemoral (TF) and the transapical (TA) approach.

METHODS

Data was analyzed using risk-adjusted regression analyses in order to track the development of clinical outcomes of all isolated TAVI procedures performed in Germany from 2008 to 2013 (N=32.436) in all German hospitals performing TAVI. Measurements include in-hospital mortality, stroke, bleeding, and mechanical ventilation.

RESULTS

Unadjusted mortality rates decrease over time for both TA-TAVI and TF-TAVI. Reductions in mortality were smaller for TA-TAVI than for TF-TAVI. These trends could also be observed for risk-adjusted (standardized) mortality rates, indicating that time trends and differences between TA-TAVI (around 7% in 2013) and TF-TAVI (around 4% in 2013) cannot be explained by changes in the risk factor composition of the patient populations. Bleeding complications decreased for both access routes. Both unadjusted and standardized bleeding rates were substantially higher for TA-TAVI. In addition, TA-TAVI procedures were associated with an increased likelihood of requiring >48h of mechanical ventilation.

CONCLUSIONS

Observed improvements in TAVI-related in-hospital mortality are not due to a change in patient population. The results indicate the superiority of a TF-first approach.