SPC365

Computed Tomography-derived myocardial extracellular volume as a prognosis predictor in patients with severe aortic stenosis

Session: Sessão Melhores Comunicações Orais
Speaker: Rita Reis Santos

Congress: CPC 2024
Topic: P. Other
Theme: 37. Miscellanea
Subtheme: 03.2 Computed Tomography
Session Type: Comunicações Orais
FP Number: ---
Authors: Rita Reis Santos; Rita Carvalho; Pedro M. Lopes; Francisco Gama; Pedro Freitas; Sara Guerreiro; João Abecasis; Carla Saraiva; Rui Campante Teles; Manuel de Sousa Almeida; Pedro Adragão; António M. Ferreira

<p style="text-align:center"><span style="font-size:11pt"><span style="font-family:Calibri,sans-serif"><span style="color:#000000"><strong>Background:</strong></span></span></span>&nbsp;<span style="font-size:11pt"><span style="font-family:Calibri,sans-serif"><span style="color:#000000"><span style="background-color:white"><span style="color:black">Patients with severe aortic stenosis (AS) face a higher risk of mortality, but prognosis is still heterogeneous and tools for prioritizing intervention are needed. </span></span><span style="background-color:white"><span style="color:black">Myocardial extracellular volume (ECV), measured non-invasively in pre-TAVR computed tomography (CT), is a marker of fibrosis that may reflect the degree of irreversible damage. The aim of this study was to assess the prognostic value of </span></span>CT-derived ECV (ECV<sub><span style="color:#222222">C</span>T</sub>) <span style="background-color:white"><span style="color:black">in patients with severe AS referred for TAVR-planning CT.</span></span></span></span></span></p>

<p style="text-align:center"><span style="font-size:11pt"><span style="font-family:Calibri,sans-serif"><span style="color:#000000"><strong>Methods: </strong><span style="color:black">Consecutive patients with </span>severe symptomatic AS <span style="color:black">undergoing </span>TAVR-planning CT between April and December 2022 a<span style="color:black">t single centre were prospectively included. </span>CT was performed on a 192-slice dual-source 3<sup>rd</sup>generation scanner. ECV<sub><span style="color:#222222">C</span>T</sub> was acquired during TAVR-planning using an additional post-contrast low-radiation-dose prospective acquisition. ECV<sub>CT</sub> was calculated as the ratio of change in CT attenuation (Hounsfield units [HU]) of the septal myocardium and the left ventricle (LV) blood pool before and after contrast administration, according to the equation: ECV<sub>CT</sub> = (1 &ndash; hematocrit) x (<span style="font-family:Symbol">D</span>HU<sub>myo</sub>/<span style="font-family:Symbol">D</span>HU<sub>blood</sub>) &ndash; Figure 1A.&nbsp;</span></span></span><span style="font-size:11pt"><span style="font-family:Calibri,sans-serif"><span style="color:#000000">The primary endpoint was all-cause mortality. The secondary endpoint was a composite endpoint including all-cause mortality and heart failure hospitalization.</span></span></span>&nbsp;</p>

<p style="text-align:center"><span style="font-size:11pt"><span style="font-family:Calibri,sans-serif"><span style="color:#000000"><strong>Results: </strong>A total of 138 patients were included (<span style="color:#222222">mean </span>age&nbsp;81 &plusmn; 7 years; 46% male<span style="color:#222222">; mean transaortic </span>gradient 51 &plusmn; 15 mmHg<span style="color:#222222">; mean aortic valve </span>area 0.75 &plusmn; 0.19 cm<sup>2</sup><span style="color:#222222">; mean LV ejection fraction (EF) by 2D echocardiogram </span>57 &plusmn; 11%). No patient had a clinical diagnosis of cardiac amyloidosis. Mean ECV<sub><span style="color:#222222">C</span>T </sub>was 33.9 &plusmn; 8.0%. <span style="background-color:white"><span style="color:black">During a median follow-up period of 386 days (IQR 332 &ndash; 464), </span></span>there were 18 deaths (13%), 13 before intervention and 5 after intervention; the secondary endpoint occurred in 26 patients (19%), 17 of which before intervention and 9 after. Patients who attained the primary endpoint were significantly older [81 &plusmn; 7 vs. 85 &plusmn; 7 years, P = 0.011], had lower left ventricular ejection fraction [51 &plusmn; 11 vs. 58 &plusmn; 11%, P = 0.015], higher NTproBNP levels [4739 (IQR 2003 &ndash; 9970) vs. 751 (IQR 314 &ndash; 2541), P &lt;0.001] and higher ECV values (39.9 &plusmn; 7.4% vs. 33.0 &plusmn; 7.7%, P &lt;0.001).&nbsp;</span></span></span><span style="font-size:11pt"><span style="font-family:Calibri,sans-serif"><span style="color:#000000">After adjustment for age, LVEF and NTproBNP levels, ECV<sub>CT</sub> remained an independent predictor of all-cause mortality (adjusted HR 1.09 per 1% ECV increase, 95%CI 1.02 &ndash; 1.17, p=0.005 &ndash; Figure 1B) and also the secondary endpoint (adjusted HR 1.07 per 1% ECV increase, 95%CI 1.01 &ndash; 1.13, p=0.002).</span></span></span></p>

<p style="text-align:center"><span style="font-size:11pt"><span style="font-family:Calibri,sans-serif"><span style="color:#000000"><strong><span style="color:black">Conclusions: </span></strong>In this prospective observational cohort study, interstitial fibrosis assessed by CT-derived ECV was associated with poor outcomes in patients with severe AS. <span style="color:black">ECV</span><sub>CT </sub>values<sub> </sub>may be useful to identify a subgroup of patients with higher risk who may benefit from <span style="background-color:white"><span style="color:black">earlier intervention.</span></span></span></span></span></p>