RELATIONSHIP BETWEEN WAIT-TIMES AND POST-ATRIAL FIBRILLATION ABLATION OUTCOMES: A POPULATION BASED STUDY

BACKGROUND

Rhythm control is a cornerstone of atrial fibrillation (AF) management. Shorter time between diagnosis of AF and receipt of catheter ablation is associated with greater rates of therapy success. Prior work considered diagnosis-to-ablation time as a binary or categorical variable and did not consider the unique risk profile of patients once a referral for ablation is made.

OBJECTIVES

Comprehensively assess the impact of diagnosis-to-ablation and referral-to-ablation time on post-procedural outcomes at a population level.

METHODS

This observational cohort study included patients who received catheter ablation to treat AF in Ontario, Canada. Patient demographics, medical comorbidities, AF diagnosis date, ablation referral date, and ablation date were collected. The primary outcomes of interest included a composite of death and hospitalization/emergency department visit for AF, heart failure, or ischemic stroke. Multivariable Cox models assessed the impact of diagnosis-to-ablation and referral-to-ablation times on the primary outcome.

RESULTS

Our cohort included 7,472 patients who received ablation for de novo AF between April 1, 2016 and March 31, 2022. The median diagnosis-to-ablation time was 718 (IQR:399-1274) days and the median referral-to-ablation time was 221 (IQR:117-363) days. Overall, 911 (12.2%) patients had the composite endpoint within one year of ablation. Increasing diagnosis-to-ablation time was associated with a greater incidence for the primary outcome (HR:1.02 [95%CI: 1.01-1.02] per month). Increasing referral-to-ablation time did not impact the primary outcome (HR:1.00 [95%CI: 0.98-1.01] per month).

CONCLUSION

Delays between AF diagnosis and ablation referral may contribute to adverse post-procedural outcomes, and provide an opportunity for health system quality improvements.

Transcatheter Aortic Valve Implantation Wait-Time Management: Derivation and Validation of the Canadian TAVI Triage Tool (CAN3T)

BACKGROUND

Transcatheter aortic valve implantation (TAVI) has seen indication expansion and thus exponential growth in demand over the past decade. In many jurisdictions, the growing demand has outpaced capacity, increasing wait times and preprocedural adverse events. In this study, we derived prediction models that estimate the risk of adverse events on the waitlist and developed a triage tool to identify patients who should be prioritized for TAVI.

METHODS AND RESULTS

We included adult patients in Ontario, Canada referred for TAVI and followed up until one of the following events first occurred: death, TAVI procedure, removal from waitlist, or end of the observation period. We used subdistribution hazards models to find significant predictors for each of the following outcomes: (1) all-cause death while on the waitlist; (2) all-cause hospitalization while on the waitlist; (3) receipt of urgent TAVI; and (4) a composite outcome. The median predicted risk at 12 weeks was chosen as a threshold for a maximum acceptable risk while on the waitlist and incorporated in the triage tool to recommend individualized wait times. Of 13 128 patients, 586 died while on the waitlist, and 4343 had at least 1 hospitalization. A total of 6854 TAVIs were completed, of which 1135 were urgent procedures. We were able to create parsimonious models for each outcome that included clinically relevant predictors.

CONCLUSIONS

The Canadian TAVI Triage Tool (CAN3T) is a triage tool to assist clinicians in the prioritization of patients who should have timely access to TAVI. We anticipate that the CAN3T will be a valuable tool as it may improve equity in access to care, reduce preventable adverse events, and improve system efficiency.

Impact of Neighborhood Social Deprivation on Health Care Costs Associated With TAVR

BACKGROUND

Cumulative costs of transcatheter aortic valve replacement (TAVR) differ in the referral, procedural and postprocedural phases depending on patient comorbidities, type of procedure, and procedural complications. Our goal was to determine the association between neighborhood measures of social deprivation and TAVR costs in each of the 3 phases.

METHODS

Demographics, patient comorbidities, procedural details, in-hospital complications, and costs for adults undergoing TAVR between 2017 and 2020 in Ontario, Canada were obtained from administrative databases and linked to social deprivation data using the Ontario Marginalization Index. The 3 dimensions of social deprivation assessed were (1) material deprivation, (2) residential instability, and (3) ethnic concentration. Hierarchical generalized linear models were used to determine the association between neighborhood social deprivation and cumulative TAVR costs, reported in 2018 Canadian dollars.

RESULTS

We identified a total of 7617 TAVR referrals with 3784 patients undergoing TAVR within our study period. Cumulative mean costs in the referral, procedural and postprocedural phases were $8116±$11 374, $32 790±$17 766, and $18 901±$32 490, respectively. After adjustment for clinical and demographic variables, higher factor scores in residential instability were associated with greater cumulative costs in the postprocedural phase, whereas higher factor scores in the other 2 dimensions of marginalization were not significantly associated with higher costs in any of the 3 phases.

CONCLUSIONS

This analysis shows that residential instability is associated with higher cumulative costs in the postprocedural phase of TAVR. This lays the foundation for future studies to understand the mechanism of this finding and identify potential mitigation policies.

Variation and clinical consequences of wait-times for atrial fibrillation ablation: population level study in Ontario, Canada

AIMS

Atrial fibrillation (AF) is the most common cardiac rhythm disorder. Emerging evidence supporting the efficacy of catheter ablation in managing AF has led to increased demand for this therapy, potentially outpacing the capacity to perform this procedure. Mismatch between demand and capacity for AF ablation results in wait-times which have not been comprehensively evaluated at a population level. Additionally, the consequences of such delays in AF ablation, namely the risk of hospitalization or adverse events, have not been studied.

METHODS AND RESULTS

This observational cohort study included adults referred for catheter ablation to treat AF in Ontario, Canada, between 1 April 2016 and 31 March 2020. Wait-time was defined from referral to the earliest of ablation, death, off-list, or the study endpoint of 31 March 2022. The outcomes of interest included a composite of death, hospitalization for AF/heart failure, and emergency department visit for AF/heart failure. Our study cohort included 6253 patients referred for de novo AF ablation. The median wait-time for patients who received and who did not receive ablation was 218 days (IQR: 112-363) and 520 days (IQR: 270-763), respectively. Wait-time increased consistently for patients referred between October 2017 and March 2020. Mortality was rare, but significant morbidity was observed, affecting 19.2% of patients on the waitlist for AF ablation. Paroxysmal AF was associated with a statistically significant greater risk for adverse outcomes on the waitlist (HR 1.51, 95% CI 1.18-1.93).

CONCLUSION

Wait-times for AF ablation are increasing and are associated with significant morbidity.

Regional Differences in Outcomes for patients undergoing Transcatheter Aortic Valve Replacement in New York State and Ontario

BACKGROUND

TAVR has become the standard of care for a wide spectrum of patients with severe aortic stenosis. However, there are wide variations in access to TAVR between jurisdictions. It is unknown if such variation is associated with differences in post-procedural outcomes. Our objective was to determine whether differences in health care delivery in jurisdictions with high versus low access of care to TAVR translate to differences in post-procedural outcomes.

METHODS

In this observational, retrospective cohort study, we identified all Ontario and New York State residents greater than 18 years of age who received TAVR from January 1^st, 2012, to December 31^st, 2018. Our primary outcomes were post-TAVR 30 day in-hospital mortality and all cause readmissions. Using indirect standardization, we calculated the observed versus expected outcomes for New York patients, had they been treated in Ontario.

RESULTS

Our cohort consisted of 16,814 TAVR patients at 36 hospitals in New York State and 5,007 TAVR patients at 11 hospitals in Ontario. In Ontario, TAVR access rates increased from ∼18.2 TAVR/million in 2012 to 87.4 TAVR/million in 2018, while for New York State, the rates increased from 31.9 to 220.4 TAVR/million. For 30-day mortality, 3.1% of Ontario TAVR patients had an in-hospital death, compared to 2.5% of New York patients. With adjustment, this translated to an observed/expected ratio of 0.70 (95% CI 0.54-0.92) for New York patients.

CONCLUSIONS

Having greater access to TAVR maybe associated with improved outcomes, potentially due to an intervention earlier in the disease trajectory.

Social Deprivation and Post-TAVR Outcomes in Ontario, Canada: A Population-Based Study

Background Transcatheter aortic valve replacement (TAVR)/intervention has become the standard of care for treatment of severe aortic stenosis across the spectrum of risk. There are socioeconomic disparities in access to TAVR. The impact of these disparities on postprocedural outcomes remains unknown. Our objective was to examine the association between neighborhood-level social deprivation and post-TAVR mortality and hospital readmission. Methods and Results We conducted a population-based retrospective cohort study of all 4145 patients in Ontario, Canada, who received TAVR from April 1, 2017, to March 31, 2020. Our co-primary outcomes were 1-year postprocedure mortality and 1-year postprocedure readmission. Using Cox proportional hazards models for mortality and cause-specific competing risk hazard models for readmission, we evaluated the relationship between neighborhood-level measures of residential instability, material deprivation, and concentration of racial and ethnic groups with post-TAVR outcomes. After multivariable adjustment, we found a statistically significant relationship between residential instability and postprocedural 1-year mortality, ranging from a hazard ratio of 1.64 to a hazard ratio of 2.05. There was a significant association between the highest degree of residential instability and 1-year readmission (hazard ratio, 1.23 [95% CI, 1.01-1.49]). There was no association between material deprivation and concentration of racial and ethnic groups with post-TAVR outcomes. Conclusions Residential instability was associated with increased risk for post-TAVR mortality, and the highest quintile of residential instability was associated with increased post-TAVR readmission. To reduce health disparities and promote an equitable health care system, further research and policy interventions will be required to identify and support economically and socially minoritized patients undergoing TAVR.

Risk Factors for Hospital Readmission Post-Transcatheter Aortic Valve Implantation in the Contemporary Era: A Systematic Review

Background

Despite transcatheter aortic valve implantation (TAVI) becoming a widely accepted therapeutic option for the management of aortic stenosis, post-procedure readmission rates remain high. Rehospitalization is associated with negative patient outcomes, as well as increased healthcare costs, and has therefore been identified as an important target for quality improvement. Strategies to reduce the post-TAVI readmission rate are needed but require the identification of patients at high risk for rehospitalization. Our systematic review aims to identify predictors of post-procedure readmission in patients eligible for TAVI.

Methods

We conducted a comprehensive search of the MEDLINE, Embase, and Cochrane Central Register of Controlled Trials (CENTRAL) databases for the time period from 2015 to the present for articles evaluating risk factors for rehospitalization post-TAVI with a follow-up period of at least 30 days in adults age ≥ 70 years with aortic stenosis. The quality of included studies was evaluated using the Newcastle-Ottawa Scale. We present the results as a qualitative narrative review.

Results

We identified 49 studies involving 828,528 patients. Post-TAVI readmission is frequent, and rates vary (14.9% to 54.3% at 1 year). The most-frequent predictors identified for both 30-day and 1-year post-TAVI readmission are atrial fibrillation, lung disease, renal disease, diabetes mellitus, in-hospital life-threatening bleeding, and non-femoral access.

Conclusions

This systematic review identifies the most-common predictors for 30-day and 1-year readmission post-TAVI, including comorbidities and potentially modifiable procedural approaches and complications. These predictors can be used to identify patients at high-risk for readmission who are most likely to benefit from increased support and follow-up post-TAVI.

Drivers and outcomes of variation in surgical versus transcatheter aortic valve replacement in Ontario, Canada: a population-based study

Objectives

To understand the patient and hospital level drivers of the variation in surgical versus trascatheter aortic valve replacement (SAVR vs TAVR) for patients with aortic stenosis (AS) and to explore whether this variation translates into differences in clinical outcomes.

Background

Adoption of TAVR has grown exponentially worldwide. Notwithstanding, a wide variation in TAVR rates has been seen within and between countries and in some jurisdictions AS is still primarily being managed by SAVR.

Methods

We conducted a population-based retrospective cohort study in Ontario, Canada, including individuals who received TAVR or SAVR between 2016 and 2020. We developed iterative hierarchical logistic regression models for the likelihood of receiving TAVR instead of SAVR examining sequentially patient characteristics, hospital factors and year of procedure, calculating the median ORs and variance partition coefficients for each. Using Cox proportional hazards models, we examined the relationship between TAVR/SAVR ratio on all-cause mortality and readmissions.

Results

Annual procedures rates per million population increased from 171 to 201, mainly driven by the expansion of TAVR. TAVR/SAVR ratios differed substantially between hospitals, from 0.21 to 3.27. Neither patient nor hospital factors explained the between-hospital variation in AS treatment. The TAVR/SAVR ratio was significantly associated with clinical outcomes with high ratio hospitals having lower mortality and rehospitalisations.

Conclusions

Despite the expansion of TAVR, dramatic variation exists that is not explained by patient or hospital factors. This variation was associated with differences in clinical outcomes, suggesting that further work is needed in understanding and addressing inequity of access.

Temporal Trends and Drivers of Heart Team Utilization in Transcatheter Aortic Valve Replacement: A Population-Based Study in Ontario, Canada

Background

The multidisciplinary Heart Team (HT) is recommended for management decisions for transcatheter aortic valve replacement (TAVR) candidates, and during TAVR procedures. Empiric evidence to support these recommendations is limited. We aimed to explore temporal trends, drivers, and outcomes associated with HT utilization.

Methods and Results

TAVR candidates were identified in Ontario, Canada, from April 1, 2012 to March 31, 2019. The HT was defined as having a billing code for both a cardiologist and cardiac surgeon during the referral period. The procedural team was defined as a billing code during the TAVR procedure. Hierarchical logistical models were used to determine the drivers of HT. Median odds ratios were calculated to quantify the degree of variation among hospitals. Of 10 412 patients referred for TAVR consideration, 5489 (52.7%) patients underwent a HT during the referral period, with substantial range between hospitals (median odds ratio of 1.78). Utilization of a HT for TAVR referrals declined from 69.9% to 41.1% over the years of the study. Patient characteristics such as older age, frailty and dementia, and hospital characteristics including TAVR program size, were found associated with lower HT utilization. In TAVR procedures, the procedural team included both cardiologists and cardiac surgeons in 94.9% of cases, with minimal variation over time or between hospitals.

Conclusions

There has been substantial decline in HT utilization for TAVR candidates over time. In addition, maturity of TAVR programs was associated with lower HT utilization.

Predictors of cumulative cost for patients with severe aortic stenosis referred for surgical or transcatheter aortic valve replacement: a population-based study in Ontario, Canada

AIMS 

Transcatheter aortic valve replacement (TAVR) as an alternative to surgical aortic valve replacement (SAVR) has transformed severe aortic stenosis (AS) management. Our aim was understand AS cost drivers from referral to 1-year post-procedure.

METHODS AND RESULTS 

We identified patients referred for either TAVR/SAVR between 1 April 2015 and 31 March 2018, with follow-up until 31 March 2019 in Ontario, Canada. We stratified costs into (i) a referral phase, (ii) a procedural phase from the procedure date to 60 days post-procedure, and (iii) post-procedure phase from 61 days to 1 year. Multivariable regression modelling using generalized linear models with a log link gamma distribution was used to identify cost drivers in each phase. The study cohort included 12 086 AS patients; 4832 were referred for TAVR and 7254 were referred for SAVR. The median cost for TAVR was higher than SAVR in the referral ($3593 vs. $2944) and post-procedural ($5938 vs. $3257) phases. In contrast, for the procedural phase, SAVR had a median cost of $29 756 vs. $27 907 for TAVR. Predictors of high cost in the referral phase were longer wait-time, and an urgent in-hospital procedure. In the procedural phase, procedural complications were the major drivers of higher cost. In the post-procedural phase, patient co-morbidities were the major drivers, specifically dialysis, liver disease, cancer, peripheral vascular disease, and diabetes mellitus.

CONCLUSION 

We identified distinct patterns of cost accumulation and modifiable drivers for SAVR compared with TAVR; these drivers may guide clinical and health policy decisions to make AS care more efficient.

Predictors of Long-term Cardiovascular Versus Non-cardiovascular Mortality and Repeat Intervention in Patients Having Transcatheter Aortic Valve Implantation

There is a paucity of literature characterizing the risk of long-term mortality and reintervention after transcatheter aortic valve implantation (TAVI). Addressing this gap has become increasingly relevant with the inclusion of intermediate and low surgical risk patients and the need for data to inform their long-term management. We sought to investigate the long-term trends and predictors of cardiovascular versus noncardiovascular mortality as well as reintervention in post-TAVI patients. Our cohort consisted of 5,406 patients who underwent TAVI in Ontario, Canada from 2011 to 2018. We used Kaplan-Meier analysis to estimate 7-year all-cause mortality and a Cox proportional hazard model to identify demographic, co-morbid, and procedural predictors. Similarly, cumulative incidence functions were used to estimate cardiovascular versus noncardiovascular mortality at 5 years, with predictors identified through Fine-Gray models. The Kaplan-Meier estimate for 7-year all-cause mortality in our cohort was 67%; this was driven by a number of co-morbidities including congestive heart failure and liver disease. We found that cardiovascular death was more likely for approximately the first 2 years post-TAVI whereas noncardiovascular death was more likely from this point to the end of the study. We identified a number of factors that uniquely modified the risk of either cardiovascular or noncardiovascular mortality. Only 1.6% of patients who underwent repeat intervention. The distinct factors associated with cardiovascular versus noncardiovascular death suggest different approaches to short-term and long-term surveillance of patients post-TAVI by both the heart team and primary care providers.