Three-dimensional thoracic aorta principal strain analysis from routine ECG-gated computerized tomography: feasibility in patients undergoing transcatheter aortic valve replacement.

BACKGROUND: Functional impairment of the aorta is a recognized complication of aortic and aortic valve disease. Aortic strain measurement provides effective quantification of mechanical aortic function, and 3-dimenional (3D) approaches may be desirable for serial evaluation. Computerized tomographic angiography (CTA) is routinely performed for various clinical indications, and offers the unique potential to study 3D aortic deformation. We sought to investigate the feasibility of performing 3D aortic strain analysis in a candidate population of patients undergoing transcatheter aortic valve replacement (TAVR). METHODS: Twenty-one patients with severe aortic valve stenosis (AS) referred for TAVR underwent ECG-gated CTA and echocardiography. CTA images were analyzed using a 3D feature-tracking based technique to construct a dynamic aortic mesh model to perform peak principal strain amplitude (PPSA) analysis. Segmental strain values were correlated against clinical, hemodynamic and echocardiographic variables. Reproducibility analysis was performed. RESULTS: The mean patient age was 81±6 years. Mean left ventricular ejection fraction was 52±14%, aortic valve area (AVA) 0.6±0.3 cm2 and mean AS pressure gradient (MG) 44±11 mmHg. CTA-based 3D PPSA analysis was feasible in all subjects. Mean PPSA values for the global thoracic aorta, ascending aorta, aortic arch and descending aorta segments were 6.5±3.0, 10.2±6.0, 6.1±2.9 and 3.3±1.7%, respectively. 3D PSSA values demonstrated significantly more impairment with measures of worsening AS severity, including AVA and MG for the global thoracic aorta and ascending segment (p<0.001 for all). 3D PSSA was independently associated with AVA by multivariable modelling. Coefficients of variation for intra- and inter-observer variability were 5.8 and 7.2%, respectively. CONCLUSIONS: Three-dimensional aortic PPSA analysis is clinically feasible from routine ECG-gated CTA. Appropriate reductions in PSSA were identified with increasing AS hemodynamic severity. Expanded study of 3D aortic PSSA for patients with various forms of aortic disease is warranted.

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.

The Vancouver 3M (Multidisciplinary, Multimodality, But Minimalist) Clinical Pathway Facilitates Safe Next-Day Discharge Home at Low-, Medium-, and High-Volume Transfemoral Transcatheter Aortic Valve Replacement Centers: The 3M TAVR Study.

OBJECTIVES: The authors sought to prospectively determine the safety and efficacy of next-day discharge using the Vancouver 3M (Multidisciplinary, Multimodality, but Minimalist) Clinical Pathway. BACKGROUND: Transfemoral transcatheter aortic valve replacement (TAVR) is an alternative to surgery in high- and intermediate-risk patients; however, hospital stays average at least 6 days in most trials. The Vancouver 3M Clinical Pathway is focused on next-day discharge, made possible by the use of objective screening criteria as well as streamlined peri- and post-procedural management guidelines. METHODS: Patients were enrolled from 6 low-volume (<100 TAVR/year), 4 medium-volume, and 3 high-volume (>200 TAVR/year) centers in Canada and the United States. The primary outcomes were a composite of all-cause death or stroke by 30 days and the proportion of patients successfully discharged home the day following TAVR. RESULTS: Of 1,400 screened patients, 411 were enrolled at 13 centers and received a SAPIEN XT (58.2%) or SAPIEN 3 (41.8%) valve (Edwards Lifesciences, Irvine, California). In centers enrolling exclusively in the study, 55% of screened patients were enrolled. The median age was 84 years (interquartile range: 78 to 87 years) with a median STS score of 4.9% (interquartile range: 3.3% to 6.8%). Next-day discharge home was achieved in 80.1% of patients, and within 48 h in 89.5%. The composite of all-cause mortality or stroke by 30 days occurred in 2.9% (95% confidence interval: 1.7% to 5.1%), with neither component of the primary outcome affected by hospital TAVR volume (p = 0.51). Secondary outcomes at 30 days included major vascular complication 2.4% (n = 10), readmission 9.2% (n = 36), cardiac readmission 5.7% (n = 22), new permanent pacemaker 5.7% (n = 23), and >mild paravalvular regurgitation 3.8% (n = 15). CONCLUSIONS: Adherence to the Vancouver 3M Clinical Pathway at low-, medium-, and high-volume TAVR centers allows next-day discharge home with excellent safety and efficacy outcomes.

Evolution of Procedural and Clinical Outcomes After Balloon-Expanding Transcatheter Aortic Valve Implantation In Canada (from the Early Canadian Experience and SOURCE XT Registries).

Transcatheter aortic valve implantation (TAVI) has evolved globally, yet its evolution and performance across the Canadian landscape have yet to be formally assessed. Patients captured within the early Canadian TAVI experience with a balloon-expanding valve (n = 339; 2005 to 2009) and those enrolled in the Canadian SOURCE XT registry (n = 415; 2012 to 2015) were systematically compared with respect to baseline clinical, echocardiographic, and procedural characteristics. Valve-related and clinical outcomes were compared across the 2 time periods according to standardized definitions. Notable baseline between-group differences were noted across time, with Society of Thoracic Surgeons Predicted Risk of Mortality score being lower in the SOURCE XT cohort compared with the earlier Canadian cohort (7.4 ± 6.6% vs 9.8 ± 6.4%, p <0.001). The SOURCE XT cohort underwent TAVI through the transfemoral approach more frequently than their earlier Canadian counterparts (75% vs 48%), at the expense of transapical access, with major access site vascular complications (2.7% vs 13%), and ≥mild residual aortic regurgitation (39% vs 69%) being significantly less frequent (p <0.001 for all). At 30-days, there were no significant differences in rates of stroke (1.9% vs 2.4%) or new pacemakers (5.8% vs 5.0%); however, 30-day and 1-year mortality rates were significantly lower in the SOURCE XT cohort (3.6% vs 10.4%; 13.0% vs 24.2%, respectively, p<0.001 for both). In conclusion, TAVIs evolution in Canada with a balloon-expanding valve coincided with more optimized patient selection and increasing use of transfemoral access, which along with increasing operator experience, contributed to improved procedural and longer term clinical outcomes.

Aspirin Versus Aspirin Plus Clopidogrel as Antithrombotic Treatment Following Transcatheter Aortic Valve Replacement With a Balloon-Expandable Valve: The ARTE (Aspirin Versus Aspirin + Clopidogrel Following Transcatheter Aortic Valve Implantation) Randomized Clinical Trial.

OBJECTIVES: The aim of this study was to compare aspirin plus clopidogrel with aspirin alone as antithrombotic treatment following transcatheter aortic valve replacement (TAVR) for the prevention of ischemic events, bleeding events, and death. BACKGROUND: Few data exist on the optimal antithrombotic therapy following TAVR. METHODS: This was a randomized controlled trial comparing aspirin (80 to 100 mg/day) plus clopidogrel (75 mg/day) (dual antiplatelet therapy [DAPT]) versus aspirin alone (single-antiplatelet therapy [SAPT]) in patients undergoing TAVR with a balloon-expandable valve. The primary endpoint was the occurrence of death, myocardial infarction (MI), stroke or transient ischemic attack, or major or life-threatening bleeding (according to Valve Academic Research Consortium 2 definitions) within the 3 months following the procedure. The trial was prematurely stopped after the inclusion of 74% of the planned study population. RESULTS: A total of 222 patients were included, 111 allocated to DAPT and 111 to SAPT. The composite of death, MI, stroke or transient ischemic attack, or major or life-threatening bleeding tended to occur more frequently in the DAPT group (15.3% vs. 7.2%, p = 0.065). There were no differences between groups in the occurrence of death (DAPT, 6.3%; SAPT, 3.6%; p = 0.37), MI (DAPT, 3.6%; SAT, 0.9%; p = 0.18), or stroke or transient ischemic attack (DAPT, 2.7%; SAPT, 0.9%; p = 0.31) at 3 months. DAPT was associated with a higher rate of major or life-threatening bleeding events (10.8% vs. 3.6% in the SAPT group, p = 0.038). There were no differences between groups in valve hemodynamic status post-TAVR. CONCLUSIONS: This small trial showed that SAPT (vs. DAPT) tended to reduce the occurrence of major adverse events following TAVR. SAPT reduced the risk for major or life-threatening events while not increasing the risk for MI or stroke. Larger studies are needed to confirm these results. (Aspirin Versus Aspirin + Clopidogrel Following Transcatheter Aortic Valve Implantation: The ARTE Trial [ARTE], NCT01559298; Aspirin Versus Aspirin+Clopidogrel as Antithrombotic Treatment Following TAVI [ARTE], NCT02640794).