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Funding Acknowledgements Type of funding sources: Other. Main funding source(s): Bangerter-Rhyner Foundation, Pfizer, GAMBIT foundation. Background Transthyretin amyloid cardiomyopathy (ATTR-CM) may coexist in patients with severe aortic stenosis (AS) considered for transcatheter aortic valve implantation (TAVI). The diagnosis of ATTR-CM by 99mTechnetium-3,3-diphosphono-1,2-propanodicarboxylic-acid (DPD)-scintigraphy is costly, whereas endomyocardial biopsy is associated with relevant procedural risks and sampling error. Objectives To evaluate whether ATTR-CM may be diagnosed by routine 4D cardiac computed tomography (4DCCT). Methods In a prospective screening study for ATTR-CM, the diagnostic performance of 4DCCT-based left- (LV), right ventricular (RV) and left atrial (LA) dimensions, ejection fraction (EF) and myocardial strain was evaluated against DPD-scintigraphy to identify ATTR-CM. Diagnostic predictors and a newly developed 4DCCT-score were validated by internal bootstrapping. Results Among 263 patients considered for TAVI (57% males,age 83±4.6 years) undergoing 4DCCT, DPD-scintigraphy (Perugini grade 2–3) confirmed co-existing ATTR-CM in 27 (10.3%) patients. Patients with ATTR-CM had impaired 4DCCT-based LVEF, LV global longitudinal strain (GLS), and LA-GLS. LV mass index, LV-GLS, LA-GLS and relative apical longitudinal strain (ratio of apical to basal/midventricular strain), each predicted the presence of ATTR-CM with an area under the curve (AUC) of >0.7. Implementing these parameters with cutoff-values of ≥81g/m2, ≥-14.9%, <11.5% and ≥1.7 in an unweighted score yielded high prognostic accuracy (AUC=0.89; 95%CI:0.81–0.94;p<0.001), robust to internal bootstrapping validation (AUC=0.88;95%CI:0.82–0.94). If two criteria were fulfilled, sensitivity and specificity to detect ATTR-CM were 96.3 and 58.9%, respectively. Conclusions Clinically indicated, routine 4DCCT in patients considered for TAVI provides high diagnostic yield to detect concomitant ATTR-CM, by assessing LV- and LA-GLS, LV relative apical longitudinal strain and LV mass index.

Preprocedural planning and postprocedural evaluation after transcatheter treatment of severe tricuspid regurgitation remain challenging and require further research and standardization. We illustrate the use of multimodality imaging techniques in 3 patients undergoing implantation of a novel custom-made bicaval valved stent for symptomatic treatment of severe tricuspid regurgitation. ( Level of Difficulty: Advanced. )