Computed tomography derived left ventricular global longitudinal strain associate with clinical outcomes in patients undergoing transcatheter aortic valve replacement

Funding Acknowledgements

Type of funding sources: None.

Background

Computed tomography angiography (CTA) is key imaging modality for procedure planning for transcatheter aortic valve replacement (TAVR). Functional assessment by CTA with LV global longitudinal strain (LVGLS) has recently shown to be feasible. However, there is limited data on its prognostic value in patients with severe aortic stenosis (AS) who treated with TAVR.

Purpose

To evaluate the association of baseline CTA-LVGLS with post-TAVR outcome.

Methods

 Patients who underwent contrast multiphasic gated CTA for TAVR planning were studied. LVGLS was measured using dedicated feature-tracking software (Medis®). Cox regression analysis evaluated the association of baseline LVGLS with a composite outcome of all-cause death and heart failure hospitalization after TAVR.

Results

A total of 431 patients were included (median [IQR] age, 83 [77,87]years; 44% female); the society of Thoracic Surgeons Predicted Risk of Mortality (STS-PROM) score, 3.3 [2.3,5.1]%; CTA-LVGLS, -18.0 [-21.6,-14.2]%; LV ejection fraction was preserved at 60 [55,65]%. After a median follow-up of 19 [13,27] months, 99 composite outcomes occurred after TAVR. On multivariable Cox regression analysis, LVGLS was associated with the risk of composite outcome even after adjustment for baseline characteristics (Figure A). Patients with reduced LVGLS (above the median >-18.0%) had higher risk of the composite outcome than those with preserved GLS (p = 0.003; Figure B).

Conclusion

Baseline CTA-LVGLS was associated with the risk of death or heart failure hospitalization over the clinical and echocardiographic characteristics in severe AS patients undergoing TAVR.

Abstract Figure.

Computed tomography characteristics of patients with functional MR receiving MitraClip

Funding Acknowledgements

Type of funding sources: None.

Background

Percutaneous leaflet repair with the MitraClip device (Abbott Vascular, Menlo Park, CA) is safe and effective in patients with severe functional mitral regurgitation (FMR). Residual or recurrent MR may occur in up to 40% of patients and is associated with persistent symptoms and impaired survival. The anatomical characteristics associated with residual or recurrent MR after MitraClip are not well defined by computed tomography angiography (CTA) in FMR population.

Methods

A retrospective analysis of patients with significant FMR, who underwent retrospective-gated CTA at Minneapolis Heart Institute between July 2015 to January 2020, identified those who underwent percutaneous leaflet repair with MitraClip. Anatomical and functional parameters were assessed by pre-procedure CTA and compared between those with and without residual (≥2) MR.

Results

  A total of 25 patients were included (median[Q1, Q3]; age, 80[75, 85]; 44% men) and classified into ventricular FMR (V-FMR, n = 12) and atrial FMR (A-FMR, n = 13) according to anatomical and functional characteristics by CTA. 50% of V-FMR and 38% of A-FMR had residual/worsening MR. Among V-FMR patients with residual/worsening MR, shorter coaptation length was observed (2.2[2, 2.3] mm vs. 3.5[3, 4], p = 0.006) (Figure). No differences in anatomical or functional characteristics were seen in A-FMR patients.

Conclusion

Longer coaptation length in V-FMR is predictive of successful MitraClip procedure, whereas mitral annulus size and cardiac volumes are not.

<Ventricular FMR> Total (N = 12) No residual/no worsening MR (N = 6) Residual/worsening MR (N = 6) P value Septal-lateral diameter, mm 31.9 (30.5, 37.9) 32.2 (30.1, 39.8) 31.9 (29.5, 35) 0.749 Annulus area, cm² 11.2 (10.4, 13.6) 11.3 (10.1, 14.6) 11.1 (9.6, 12.6) 0.631 Tenting area, cm² 1.6 (1.3, 2.1) 1.6 (1.2, 2.2) 1.7 (1.2, 2.3) 0.873 Tenting height, mm 8.5 (6.5, 9.7) 8.5 (6.6, 9.3) 8.3 (6.3, 10.1) 0.749 Coaptation length, mm 2.6 (2.1, 3.5) 3.5 (3.0, 4.0) 2.2 (2.0, 2.3) 0.006 <Atrial FMR> Total (N = 13) No residual/no worsening MR (N = 8) Residual/worsening MR (N = 5) P value Septal-lateral diameter, mm 32.3 (29.5, 39.0) 32.0 (29.2, 39.9) 34.3 (30.8, 39.02) 0.464 Annulus area, cm² 10.3 (9.2, 14.7) 10.2 (9.0, 14.6) 12.4 (9.4, 14.7) 0.661 Tenting area, cm² 1.2 (0.8, 1.8) 1.1 (0.7, 2.2) 1.3 (0.7, 1.8) 0.884 Tenting height, mm 5.5 (4.1, 6.9) 6.3 (4.1, 8.7) 4.6 (3.7, 5.8) 0.213 Coaptation length, mm 2.3 (1.5, 2.8) 2.5 (1.4, 3.5) 1.9 (1.5, 2.6) 0.464 Comparison of baseline CT parameters between no residual/ no worsening MR and residual/ worsening MR Abstract Figure.

P212 Computed tomography derived left ventricular outflow tract area downgrades severity of prosthesis-patient mismatch after transcatheter aortic valve replacement

Background

Prosthesis-patient mismatch (PPM) is associated with poor outcomes after surgical aortic valve replacement, but evidence in the era of transcatheter aortic valve replacement (TAVR) is small. Although PPM is conventionally defined by transthoracic echocardiogram (TTE) derived indexed effective orifice area (EOAi), TTE may underestimate left ventricular outflow tract (LVOT) area when compared with cardiac computed tomography angiography (CTA).

Purpose

To evaluate the inter-modality (TTE vs CTA) agreement and inter-valve (balloon-expanding valve (BEV) vs. self-expandable valve (SEV)) differences in EOAi and the severity of PPM after TAVR.

Methods

We analyzed all patients who underwent TAVR between 2015 to 2017and who had both of CTA and TTE at 30-days after TAVR. EOAi was calculated using the continuity equation and then indexed to body surface area as per guidelines using TTE derived LVOT diameter (EOAi-TTE) or post-procedure CTA derived LVOT area (EOAi-CTA). The external LVOT diameter was measured at inflow of TAVR bioprosthetic stent frame as per recommendations. The EOAi was used to define the grading severity of PPM: None (> 0.85 cm²/m²); Moderate (0.65 to 0.85 cm²/m²); and Severe (< 0.65 cm²/m²). Paired or Student t-test and Chi-square test were used to assess the inter-modality and inter-valve difference.

Results

A total of 280 patients were included (the mean age, 81.2 ± 8.1 years; 48%, female). BEV was used in 150 patients (54%). The mean EOAi-TTE vs. EOAi-CTA was 1.00 ± 0.32 and 1.41 ± 0.50 cm²/m², respectively, p < 0.001. Prevalence of severe (TTE 9% versus CTA 4%, p < 0.01) and moderate (TTE 28% versus CTA 7%, p < 0.01) PPM was lower when adjudicated by CTA (Figure-Panel A). There was a trends towards smaller EOAi by either TTE (0.97 ± 0.31 vs. 1.04 ± 0.33, p = 0.07) or CTA (1.38 ± 0.45 vs. 1.46 ± 0.56, p = 0.21) for BEV vs. SEV (Figure-Panel B). There was no significant difference in the severity of PPM defined by either EOAi-TTE (Figure-Panel C) or EOAi-CTA (Figure-Panel D) between these patients.

Conclusion

EOAi-CTA was larger and downgraded the severity of PPM than the EOAi-TTE. There was no significant difference in the severity of PPM defined by post-procedure CT between patients treated with BEV and those with SEV.

Abstract P212 Figure.

Reduction in radiation exposure in cardiovascular computed tomography imaging: results from the PROspective multicenter registry on radiaTion dose Estimates of cardiac CT angIOgraphy iN daily practice in 2017 (PROTECTION VI)

Aims

Advances of cardiac computed tomography angiography (CTA) have been developed for dose reduction, but their efficacy in clinical practice is largely unknown. This study was designed to evaluate radiation dose exposure and utilization of dose-saving strategies for contrast-enhanced cardiac CTA in daily practice.

Methods and results

Sixty one hospitals from 32 countries prospectively enrolled 4502 patients undergoing cardiac CTA during one calendar month in 2017. Computed tomography angiography scan data and images were analysed in a central core lab and compared with a similar dose survey performed in 2007. Linear regression analysis was performed to identify independent predictors associated with dose. The most frequent indication for cardiac CTA was the evaluation of coronary artery disease in 89% of patients. The median dose-length product (DLP) of coronary CTA was 195 mGy*cm (interquartile range 110-338 mGy*cm). When compared with 2007, the DLP was reduced by 78% (P < 0.001) without an increase in non-diagnostic coronary CTAs (1.7% in 2007 vs. 1.9% in 2017 surveys, P = 0.55). A 37-fold variability in median DLP was observed between the hospitals with lowest and highest DLP (range of median DLP 57-2090 mGy*cm). Independent predictors for radiation dose of coronary CTA were: body weight, heart rate, sinus rhythm, tube voltage, iterative image reconstruction, and the selection of scan protocols.

Conclusion

This large international radiation dose survey demonstrates considerable reduction of radiation exposure in coronary CTA during the last decade. However, the large inter-site variability in radiation exposure underlines the need for further site-specific training and adaptation of contemporary cardiac scan protocols.

Detection of Atrial Fibrillation and Atrial Flutter by Pacemaker Device Interrogation After Transcatheter Aortic Valve Replacement (TAVR): Implications for Management

BACKGROUND

Atrial fibrillation (AF) and atrial flutter (AFL) are associated with increased risk of stroke and mortality after transcatheter aortic valve replacement (TAVR). Many episodes of new-onset AF/AFL (NOAF) occur after hospital discharge and may not be clinically apparent. Pacemakers can detect subclinical episodes of rapid atrial rate, which correlate with electrocardiographically documented AF.

METHODS

From 2012 to 2017, patients who underwent pacemaker implantation after TAVR were reviewed, and pacemaker data from device checks were analyzed for detection of NOAF. Patients with prior AF/AFL were excluded. Secondary outcomes were mortality and ischemic stroke.

RESULTS

A total of 172 patients underwent TAVR and pacemaker implantation, and 95 were without pre-existent AF/AFL. Over a median follow-up of 15 months, a total of 24 patients had NOAF (25%), of which 10 patients (10.5%) had manifest NOAF detected on electrocardiography, and 14 patients (14.7%) had subclinical NOAF first identified on device interrogation. The cumulative incidence of mortality was 16.7% for NOAF and 15.5% for normal sinus rhythm (P=.83). The cumulative incidence of stroke was 12.5% for NOAF and 1.4% for normal sinus rhythm (P=.04). Subclinical NOAF patients were less likely to be started on anticoagulation compared with manifest NOAF patients (70% vs 15.3%, respectively; P=.02).

CONCLUSION

Subclinical NOAF is common after TAVR, usually occurs months after hospital discharge, and is associated with lack of anticoagulation therapy and increased risk of stroke. Prolonged surveillance of subclinical NOAF may be warranted after TAVR.

Development of a congenital cardiovascular computed tomography imaging registry: Rationale and implementation

BACKGROUND

The cumulative exposure and risk of anesthesia, vascular access, contrast agents and radiation is emerging as a significant lifelong burden in patients with congenital heart disease (CHD). Latest generation computerized tomographic (CT) scanners are increasingly used for high resolution cardiovascular imaging and have both hardware and post processing radiation dose reduction strategies that can be implemented. Currently, these dose reduction strategies are not uniformly applied and there is a large variability in radiation dose used for the performance of CT in CHD.

METHODS

We propose the development and implementation of a prospective, multi-center and multi-specialty consortium to measure the variability of use, risk and image quality of CT scans in patients of all ages with CHD. The primary goals of this collaboration are 1) define variability of use, diagnostic quality, and risk of cardiac CT 2) establish best practice guidelines designed to optimize diagnostic image quality with appropriate use of radiation and anesthesia exposure 3) provide institution specific feedback compared with the group norm across participating centers 4) improve the level of evidence for the use of CT in CHD through the collection of prospective and multi-institutional data.

CONCLUSIONS

Prospective multi-institutional data is needed to inform risk estimates of CT in CHD using current generation scanners and aggressive dose optimization techniques. This registry will provide a platform for future collaboration establishing a multi-modality risk assessment tool specific to patients with CHD.

Rationale and design of the worldwide prospective multicenter registry on radiation dose estimates of cardiac CT angiography in daily practice in 2017 (PROTECTION VI)

BACKGROUND

Cardiac computed tomography angiography (cardiac CTA) is an increasingly used versatile imaging method to evaluate coronary and cardiac morphology. Owing to improvements in technology, image quality has continuously improved over the last 10-20 years. At the same time, numerous non-randomized and randomized studies have been performed to reduce the associated radiation exposure. Currently, it is unclear if the advances in technology and knowledge about radiation reduction translated into reduced levels of cardiac CTA radiation dose in daily clinical practice as well as a wide utilization of dose-saving strategies.

METHODS

The PROTECTION VI study is a multicenter, prospective, worldwide registry designed to evaluate radiation dose exposure, utilization of dose-saving strategies and diagnostic image quality during cardiac CTA in current daily practice. Assessment of image quality will be addressed by the evaluation of diagnostic image quality at the local study site and the calculation of quantitative image quality parameters in an imaging core laboratory. Above 4000 patients will be enrolled from approximately 70 sites in Europe, North America, South America, Asia and Australia. The study will analyze median radiation dose levels, image quality, frequency of use and efficacy of algorithms for dose reduction, and patient and study-related predictors associated with radiation dose.

CONCLUSIONS

The PROTECTION VI study is designed to provide a reliable estimate of current radiation dose for cardiac CTA and to assess the potential for additional dose reductions.

Effect of the ratio of coronary arterial lumen volume to left ventricle myocardial mass derived from coronary CT angiography on fractional flow reserve

BACKGROUND

We hypothesize that in patients with suspected coronary artery disease (CAD), lower values of the ratio of total epicardial coronary arterial lumen volume to left ventricular myocardial mass (V/M) result in lower fractional flow reserve (FFR).

METHODS

V/M was computed in 238 patients from the NXT trial who underwent coronary computed tomography angiography (CTA), quantitative coronary angiography (QCA) and FFR measurement in 438 vessels. Nitroglycerin was administered prior to CT, QCA and FFR acquisition. The V/M ratio was quantified on a patient-level from CT image data by segmenting the epicardial coronary arterial lumen volume (V) and the left ventricular myocardial mass (M). Calcified and noncalcified plaque volumes were quantified using semi-automated software.

RESULTS

The median value of V/M (18.57 mm³/g) was used to define equal groups of low and high V/M patients. Patients with low V/M had greater diameter stenosis by QCA, more plaque and lower FFR (0.80 ± 0.12 vs. 0.87 ± 0.08; P < 0.0001) than those with high V/M. A total of 365 vessels in 202 patients had QCA stenosis ≤50% and measured FFR. In these patients, those with low V/M had higher percent diameter stenosis by QCA, greater total plaque volume and lower FFR (0.81 ± 0.12 vs. 0.88 ± 0.07; P < 0.0001) than those with high V/M. In multivariate logistic regression analysis, V/M was an independent predictor of FFR ≤0.80 (all p-values < 0.001).

CONCLUSIONS

Patients with a low V/M ratio have lower FFR overall and in non-obstructive CAD, independent of plaque measures.