SPC365

Assessing the utility of the Increased Wall Thickness score in diagnosing ATTR cardiomyopathy – a validation study

Session: Comunicações Orais - Sessão 10 - Imagem em Cardiologia
Speaker: MIGUEL VAZ ALMEIDA SOBRAL DOMINGUES

Congress: CPC 2024
Topic: B. Imaging
Theme: 03. Imaging
Subtheme: 03.6 Cross-Modality and Multi-Modality Imaging Topics
Session Type: Comunicações Orais
FP Number: ---
Authors: Miguel Sobral Domingues; Rita Carvalho; Rita Lima; Pedro Freitas; Sérgio Maltez; Tânia Laranjeira; Bruno Rocha; Regina Ribeiras; Carlos Aguiar; António Ferreira

<p style="text-align:justify"><span style="font-size:12pt"><span style="font-family:Calibri,sans-serif"><strong>Introduction: </strong>Cardiac amyloidosis due to transthyretin deposition (ATTR-CM) is often underdiagnosed. An increased left ventricular wall thickness (LVWT) should raise the suspicion for ATTR-CM, but it is a very frequent and non-specific finding. In order to improve diagnostic certainty, an echocardiographic score (<em>Increased Wall</em> <em>Thickness</em> [IWT] score) was recently proposed. </span></span></p>

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<p style="text-align:justify"><span style="font-size:12pt"><span style="font-family:Calibri,sans-serif">The aim of our study was to assess the diagnostic performance of the IWT score in an independent population with increased LVWT.</span></span></p>

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<p style="text-align:justify"><span style="font-size:12pt"><span style="font-family:Calibri,sans-serif"><strong>Methods: </strong></span></span></p>

<p style="text-align:justify"><span style="font-size:12pt"><span style="font-family:Calibri,sans-serif">We conducted a retrospective analysis of 295 consecutive patients studied at our centre for increased LVWT. All patients with severe aortic stenosis (AS) had ATTR-CM excluded <span style="color:black">by endomyocardial biopsy (EMB), </span>during aortic valve replacement. <span style="color:black">ATTR-CM was considered as per the</span> ESC algorithm. To be included, patients with Hypertrophic Cardiomyopathy (HCM) <span style="color:black">performed cardiac magnetic resonance and required a sarcomeric mutation for definite diagnosis.</span></span></span></p>

<p style="text-align:justify"><span style="font-size:12pt"><span style="font-family:Calibri,sans-serif">The echocardiographic IWT score was calculated for all patients, and categorized as certain (IWT&ge;8), unlikely (IWT &le;1) or indeterminate (2 &lt;IWT&lt;8) for ATTR-CM diagnosis.</span></span></p>

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<p style="text-align:justify"><span style="font-size:12pt"><span style="font-family:Calibri,sans-serif"><strong>Results: </strong></span></span></p>

<p style="text-align:justify"><span style="font-size:12pt"><span style="font-family:Calibri,sans-serif">A total of 295 patients were included (median age of 75 years [69-81], 61% men). Overall, 230 (70%) patients had hypertension and 164 (56%) chronic kidney disease (CKD). The median LVWT was 16 mm [IQR 15-19] and the median LVEF was 57% [IRQ 50-62%]. </span></span></p>

<p style="text-align:justify"><span style="font-size:12pt"><span style="font-family:Calibri,sans-serif">After diagnostic workup, 97 patients (33%) had confirmed ATTR-CM, 129 (44%) had isolated severe AS and 71 (24%) had hypertrophic cardiomyopathy (HCM). Fifteen patients had both severe AS and ATTR-CM. </span></span></p>

<p style="text-align:justify"><span style="font-size:12pt"><span style="font-family:Calibri,sans-serif">The median IWT score was 4 (IQR 2-7), with 21% of patients (n=64) showing an IWT score &le;1, 19% an IWT score &ge;8, and 60% of patients (n=176) having an &ldquo;indeterminate&rdquo; value between 2 and 7. Despite this, on a continuous scale, the IWT showed good discriminative value (area under ROC curve 0.86, 95% 0.82-0.90, p&lt;0.001). The criteria of IWT score &ge;8 showed a positive predictive value of 82% (95% CI 72-89%), while an IWT score &le; 1 yielded a negative predictive value of 92% (95% CI 84-97%) - Figure. </span></span></p>

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<p style="text-align:justify"><span style="font-size:12pt"><span style="font-family:Calibri,sans-serif"><strong>Conclusions: </strong></span></span></p>

<p><span style="font-size:12pt"><span style="font-family:Calibri,sans-serif">Even though the IWT score provides &ldquo;indeterminate&rdquo; results in a large proportion of patients, values at the ends of the spectrum showed good negative and predictive values for the diagnosis of ATTR-CM. Our findings provide external validation for this echocardiographic score, and support its use in the diagnostic workup of patients with increased wall thickness and suspected ATTR-CM.</span></span></p>