Canadian Multicenter Chronic Total Occlusion Registry: Ten-Year Follow-Up Results of Chronic Total Occlusion Revascularization.

BACKGROUND: Chronic total occlusions (CTO) occur in nearly 20% of coronary angiograms. CTO revascularization, either by percutaneous coronary intervention (PCI) or coronary artery bypass grafting surgery (CABG), is infrequently performed, approximately one-third of cases. Long-term outcomes are unknown. The objective of the study was to determine whether early CTO revascularization of patients, either by CABG or PCI, was associated with improved clinical outcomes. METHODS: One thousand six hundred twenty-four patients from the Canadian CTO registry were followed for at least 9.75 years. Revascularization was performed according to routine clinical practice. Patients were grouped according to CTO revascularization status (PCI or CABG of CTO vessel, CTO revasc) or no CTO revasc (medical therapy only, or PCI/CABG of non-CTO vessels only), within 3 months of initial angiogram. Patients were followed for mortality, revascularization procedures (PCI and CABG), and hospitalizations for acute coronary syndromes and heart failure. RESULTS: Early CTO revasc was performed in 28.2% of patients (17.5% CABG, 10.7% PCI). The CTO revasc group was younger, with more males and generally fewer comorbidities. There was a significantly lower mortality probability at 10 years in the CTO revascularization group (22.7% [95% CI, 19.0%-26.9%]) compared with the no CTO revasc group (36.6% [95% CI, 33.8%-39.5%]). At 10 years, revascularization rates (14.0% versus 22.8%) and acute coronary syndrome hospitalization rates (10.0% versus 16.6%) were significantly lower in the CTO revasc group. Baseline-adjusted analysis showed CTO revasc was associated with significantly lower all-cause mortality (hazard ratio, 0.67 [95% CI, 0.54-0.84]). In both landmark and time varying analyses, association with lower mortality was particularly robust for CTO revascularization by CABG (hazard ratio 0.56 and 0.60, respectively), with a marginally significant result for PCI in the time varying analysis (hazard ratio 0.711 [95% CI, 0.51-0.998]). CONCLUSIONS: Early CTO revascularization was associated with significantly lower all-cause mortality, revascularization rates, and hospitalization for acute coronary syndrome at 10 years, and mainly driven by outcomes in patients with CABG.

Increasing Wait-Time Mortality for Severe Aortic Stenosis: A Population-Level Study of the Transition in Practice From Surgical Aortic Valve Replacement to Transcatheter Aortic Valve Replacement.

BACKGROUND: Transcatheter aortic valve replacement (TAVR) has emerged as a reasonable alternative to surgical aortic valve replacement (SAVR) for patients with severe aortic stenosis (AS). There is limited data on temporal trends in wait-times and access to care for patients with AS, irrespective of treatment modality. We sought to investigate the trends in wait-times for the treatment (either SAVR or TAVR) of AS in Ontario, Canada, and to understand the drivers of wait-list mortality and hospitalization due to heart failure. METHODS: In this population-level retrospective cohort study, we identified patients from April 1, 2012, to March 31, 2018, who were referred for treatment of symptomatic severe AS awaiting either SAVR or TAVR. The primary outcome was the median total wait-time from referral date to either SAVR or TAVR procedure. Primary clinical outcomes were all-cause mortality and heart failure-related hospitalizations while on the wait-list. RESULTS: The referral cohort consisted of a total of 22 876 referrals for aortic valve replacement, with (N=8098) TAVR and (N=14 778) SAVR referrals. The mean and median wait times for the overall AVR cohort were 87 and 59 days, respectively. The TAVR subcohort had longer wait-times (median 84 days) compared with the SAVR subcohort (median 50 days). Year over year, there was a statistically significant an increase in wait-times (P<0.001) for the overall AS cohort as well as each of the TAVR (P<0.0001) and SAVR (P<0.0001) subgroups. Wait-time mortality was 2.5% (TAVR 5.2% and SAVR 1.05%), while the cumulative probability of heart failure hospitalization was 3.6% (TAVR 7.7% and SAVR 1.3%). CONCLUSIONS: In patients with severe symptomatic AS awaiting aortic valve replacement, there has been a trend of increasing wait times for both SAVR and TAVR. This was associated with increasing mortality and hospitalizations related to heart failure while on the wait-list.

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.

Comparison of 1-Year Pre- and Post-Transcatheter Aortic Valve Replacement Hospitalization Rates: A Population-Based Cohort Study.

BACKGROUND: Rehospitalization rates post-transcatheter aortic valve replacement (TAVR) are high; however, it is not known how these compare with pre-TAVR hospitalization rates. Our objective was to determine the association between the index TAVR and hospitalization rates pre- and postprocedure. METHODS: A retrospective observational study was performed including all TAVR procedures performed in Ontario, Canada, between 2013 and 2017. Patients who died during the index hospitalization were excluded. The primary outcome was all-cause hospitalization within 1 year of TAVR discharge. Hospitalization rates per person-year were calculated and compared for each of the following analogous time periods pre- and post-index TAVR: 1 to 30, 31 to 90, 91 to 365, and 1 to 365 days. Poisson regression models were used to generate rate ratios to compare hospitalization rates. RESULTS: The final study cohort included 2547 patients. In the year before TAVR, 60.2% of patients were hospitalized, compared with 45.9% in the year following the procedure. The rate ratio (RR) for the year post-TAVR compared with pre-TAVR was 0.82 (95% confidence interval [CI], 0.77- 0.88). When comparing each parallel time period post- vs pre-TAVR, all intervals were associated with significant reductions in hospitalization after TAVR, except the 30-day periprocedural period. The largest change in hospitalization rates occurred in the 31 to 90 days post- vs the corresponding period pre-TAVR (RR: 0.57; 95% CI, 0.50-0.64) CONCLUSION: TAVR is associated with a significant and sustained reduction in all-cause hospitalization in the year following the procedure compared with the preprocedural period.

Predictors of Cumulative Health Care Costs Associated With Transcatheter Aortic Valve Replacement in Severe Aortic Stenosis.

BACKGROUND: There is wide variation in hospitalization costs for transcatheter aortic valve replacement (TAVR), suggesting inefficiency in care delivery. Our goal was to identify drivers of health care costs in TAVR. METHODS: Demographics, procedural details, in-hospital complications, and costs for all adults undergoing first-time TAVR from 2012 to 2016 in Ontario, Canada, were obtained through linkages of clinical/administrative databases. Total costs included were from initial referral to the first of either death or 1-year post-TAVR. Phase-based costing was performed to empirically estimate the presence, duration, and cost per patient for each phase up to 1 year or death. Multivariable regression was used to identify drivers of cost accumulation per phase. RESULTS: We identified 2009 first-time TAVR patients (mean age 81.7 ± 7.6, 45.9% female and Society of Thoracic Surgeons (STS) score of 7.2 ± 5.8). Phases of cost were identified with an early high-cost period within 60 days of referral, a second phase from the procedure to 60 days, and a stable phase from 60 to 360 days postprocedure. The referral phase median cost was $4527 (interquartile range [IQR]: 1708-12,594), the procedure to 60 days phase median cost was $29,518 (IQR: 24,842-40,279), and the post 60-day stable phase median cost was $6053 (IQR: 3320-17,048). Predictors of higher cost in the referral phase were in-hospital wait location, dialysis dependence, and heart-failure status. In the second (procedural) phase, predictors were nontransfemoral access, complications of stroke, and pacemaker insertion. Predictors of higher cost in the third (stable) phase were predominantly nonmodifiable, such as frailty. CONCLUSIONS: This analysis shows that there are 3 distinct phases of cost accumulation from referral to post-TAVR with some potentially modifiable cost drivers in each phase.

Impact of procedural capacity on transcatheter aortic valve replacement wait times and outcomes: a study of regional variation in Ontario, Canada.

BACKGROUND: There has been rapid growth in the demand for transcatheter aortic valve replacement (TAVR), which has the potential to overwhelm current capacity. This imbalance between demand and capacity may lead to prolonged wait times, and subsequent adverse outcomes while patients are on the waitlist. We sought to understand the relationship between regional differences in capacity, TAVR wait times and morbidity/mortality on the waitlist. METHODS AND RESULTS: We modelled the effect of TAVR capacity, defined as the number of TAVR procedures per million residents/region, on the hazard of having a TAVR in Ontario from April 2012 to March 2017. Our primary outcome was the time from referral to a TAVR procedure or other off-list reasons on the waitlist/end of the observation period as measured in days. Clinical outcomes of interest were all-cause mortality, all-cause hospitalisations or heart failure-related hospitalisations while on the waitlist for TAVR. There was an almost fourfold difference in TAVR capacity across the 14 regions in Ontario, ranging from 31.5 to 119.5 TAVR procedures per million residents. The relationship between TAVR capacity and wait times was complex and non-linear. In general, increased capacity was associated with shorter wait times (p<0.001), reduced mortality (HR 0.94; p=0.08) and all-cause hospitalisations (p=0.009). CONCLUSIONS: The results of the present study have important policy implications, suggesting that there is a need to improve TAVR capacity, as well as develop wait-time strategies to triage patients, in order to decrease wait times and mitigate the hazard of adverse patient outcomes while on the waitlist.

Inequity in Access to Transcatheter Aortic Valve Replacement: A Pan-Canadian Evaluation of Wait-Times.

BACKGROUND: There has been an exponential increase in the demand for transcatheter aortic valve replacement (TAVR). Our goal was to examine trends in TAVR capacity and wait-times across Canada. METHODS: All TAVR cases were identified from April 1, 2014, to March 31, 2017. Wait-time was defined as the duration in days from the initial referral to the TAVR procedure. TAVR capacity was defined as the number of TAVR procedures per million population/province/fiscal year. We performed multivariable multilevel Cox proportional hazards modelling of the time to TAVR as the dependant variable and the effect of provinces as random effects. We quantified the variation in wait-times among provinces using the median hazard ratio. RESULTS: We identified a total of 4906 TAVR procedures across 9 provinces. Despite a year over year increase in overall capacity, there was a greater than 3-fold difference in capacity between provinces. Crude median wait-times increased over time in all provinces, with marked variation from 71.5 days in Newfoundland to 190.5 and 203 days in Manitoba and Alberta, respectively. This suggests increasing demand outpaced the growth in capacity. We found a median hazard ratio of 1.62, indicating that in half of the possible pairwise comparisons, the time to TAVR for identical patients was at least 62% longer between different provinces. CONCLUSION: We found substantial geographic inequity in TAVR access. This calls for policy makers, clinicians, and administrators across Canada to address this inequity through revaluation of provincial funding mechanisms, as well as implementation of efficient care pathways.

Impact of Coronary Artery Severity and Revascularization Prior to Transcatheter Aortic Valve Implantation.

The prevalence of coexisting coronary artery disease (CAD) is high in patients who underwent transcatheter aortic valve implantation (TAVI). Our objective was to first determine if the severity of CAD before TAVI had an important impact on post-TAVI outcomes and second, if revascularization with percutaneous coronary intervention (PCI) before TAVI modified this relation. In this retrospective population-based study in Ontario, Canada, we identified all patients with obstructive CAD who underwent TAVI from April 1, 2012 to March 31, 2017. Our primary outcomes of interest were all-cause mortality within 30-day and 1-year post-TAVI procedure. Secondary outcomes included 30-day and 1-year all-cause readmissions. We developed multivariable Cox proportional hazard models, with a robust sandwich-type variance estimator to account for clustering within TAVI centers. These models included an interaction term between severity of CAD and PCI before TAVI. The study cohort included 888 of whom 444 (50%) patients underwent PCI before TAVI procedure. In the Cox models, we found that severity of CAD before TAVI was not significantly associated with post-TAVI outcomes. The only exception was 1 to 2 vessel/s disease which was a significant predictor of 1-year readmission. Pre-TAVI PCI was not significantly associated with outcomes, nor did it modify the relation between severity of CAD pre-TAVI and outcomes. In conclusion, we did not find a consistent relation between severity of CAD and revascularization with post-TAVI outcomes.

Profiling Hospital Performance on the Basis of Readmission After Transcatheter Aortic Valve Replacement in Ontario, Canada.

Background Readmission rates are a widely accepted quality indicator. Our objective was to develop models for calculating case-mixed adjusted readmission rates after transcatheter aortic valve replacement for the purpose of profiling hospitals. Methods and Results In this population-based study in Ontario, Canada, we identified all transcatheter aortic valve replacement procedures between April 1, 2012, and March 31, 2016. For each hospital, we first calculated 30-day and 1-year risk-standardized (predicted versus expected) readmission rates, using 2-level hierarchical logistic regression models, including clustering of patients within hospitals. We also calculated the risk-adjusted (observed versus expected) readmission rates, accounting for the competing risk of death using a Fine-Gray competing risk model. We categorized hospitals into 3 groups: those performing worse than expected, those performing better than expected, or those performing as expected, on the basis of whether the 95% CI was above, below, or included the provincial average readmission rate respectively. Our cohort consisted of 2129 transcatheter aortic valve replacement procedures performed at 10 hospitals. The observed readmission rate was 15.4% at 30 days and 44.2% at 1 year, with a range of 10.9% to 21.7% and 38.8% to 55.0%, respectively, across hospitals. Incorporating the competing risk of death translated into meaningful different results between models; as such, we concluded that the risk-adjusted readmission rate was the preferred metric. On the basis of the 30-day risk-adjusted readmission rate, all hospitals performed as expected, with a 95% CI that included the provincial average. However, we found that there was significant variation in 1-year risk-adjusted readmission rate. Conclusions There is significant interhospital variation in 1-year adjusted readmission rates among hospitals, suggesting that this should be a focus for quality improvement efforts in transcatheter aortic valve replacement.