SPC365

Right ventricular–pulmonary artery coupling: a functional approach to distinguishing Fabry disease from wild-type transthyretin cardiac amyloidosis

Session: Sessão de Posters 08 - Amiloidose cardíaca por transtirretina: diagnóstico e reconhecimento da doença
Speaker: Luísa Pinheiro

Congress: CPC 2026
Topic: F. Valvular, Myocardial, Pericardial, Pulmonary, Congenital Heart Disease
Theme: 17. Myocardial Disease
Subtheme: 17.3 Myocardial Disease – Diagnostic Methods
Session Type: Posters Eletrónicos
FP Number: ---
Authors: Luísa Pinheiro; Emídio Mata; Tamara Pereira; Margarida Castro; Bárbara Lage Garcia; Joana Gomes; Filipa Cordeiro; Marina Fernandes; Olga Azevedo; António Lourenço

<p style="text-align:justify"><span style="font-family:Arial,Helvetica,sans-serif"><span style="font-size:12pt"><strong>Background: </strong>Fabry disease (FD) and wild-type transthyretin cardiac amyloidosis (wtATTR-CM) can both present similar patterns of left ventricular hypertrophy. As right ventricular adaptation to afterload has emerged as a sensitive marker of early myocardial involvement, right ventricular&ndash;pulmonary artery (RV&ndash;PA) coupling metrics have gained interest as potential diagnostic indicators. </span></span></p>

<p style="text-align:justify"><span style="font-family:Arial,Helvetica,sans-serif"><span style="font-size:12pt"><strong>Aim:</strong> To evaluate the diagnostic utility of RV&ndash;PA coupling indices&mdash;TAPSE/PASP (Tricuspid Annular Plane Systolic Excursion/Pulmonary Artery Systolic Pressure), FAC/PASP (Fractional Area Change), and RV-FWS/PASP (Right Ventricular Free Wall Strain) &mdash; in differentiating FD from <span style="color:black">ATTR-CM. </span></span></span></p>

<p style="text-align:justify"><span style="font-family:Arial,Helvetica,sans-serif"><span style="font-size:12pt"><strong><span style="color:black">Methods:</span></strong><span style="color:black"> This retrospective study included 30 patients with FD and 30 with wtATTR-CM. RV structure and function were independently assessed by two blinded observers. The diagnostic performance of TAPSE/PASP, FAC/PASP, and RV-GLS/PASP ratios was evaluated using receiver operating characteristic (ROC) analysis and DeLong&rsquo;s test applied for comparison.</span></span></span></p>

<p style="text-align:justify"><span style="font-family:Arial,Helvetica,sans-serif"><span style="font-size:12pt"><strong><span style="color:black">Results:</span></strong><span style="color:black"> Patients with ATTR-CM were older than those with FD (83.4&plusmn;4.8 vs 64.6&plusmn;10.7 years, p&lt;0.001), had higher NT-proBNP levels (11,001&plusmn;15,080 vs 899&plusmn;1,016pg/ml, p&lt;0.001), and greater septal wall thickness (18.9&plusmn;2.7 vs 17.4&plusmn;2.7mm, p=0.036). ATTR-CM patients also exhibited lower RV&ndash;PA coupling indices, including TAPSE/PASP (0.428&plusmn;0.199 vs 0.871&plusmn;0.252, p&lt;0.001), FAC/PASP (0.855&plusmn;0.358 vs 1.608&plusmn;0.435, p&lt;0.001), and RV-FWS/PASP (0.246&plusmn;0.120 vs 0.507&plusmn;0.171, p&lt;0.001).</span></span></span></p>

<p style="text-align:justify"><span style="font-family:Arial,Helvetica,sans-serif"><span style="font-size:12pt"><span style="color:black">In ROC curve analysis, all three indices demonstrated good diagnostic performance for identifying ATTR-CM. TAPSE/PASP ratio had an area under the curve (AUC) of 0.924 [0.826&ndash;0.976] (p&lt;0.0001) with an associated cutoff of &le;0.679 for identifying ATTR-CM (sensitivity: 93%; specificity: 77%). FAC/PASP ratio showed an AUC of 0.917 [0.817&ndash;0.973] (p&lt;0.0001) with an associated cutoff of &le;1.25 for identifying ATTR-CM (sensitivity: 80%; specificity: 87%). The RV-FWS/PASP ratio had an AUC of 0.916 [0.815-0.972] (p&lt;0.0001) with an associated cutoff of &le;0.375 for identifying ATTR-CM (sensitivity: 90%; specificity: 83%). Pairwise comparisons showed no significant differences among the three ratios. When compared to the right ventricular function parameters not normalized to load, the AUCs were always numerically lower than those of the load-normalized parameters (AUC of 0.836 for TAPSE, AUC of 0.829 for FAC and AUC of 0.888 for RV-FWS).</span></span></span></p>

<p style="text-align:justify"><span style="font-family:Arial,Helvetica,sans-serif"><span style="font-size:12pt"><strong><span style="color:black">Conclusion:</span></strong><span style="color:black"> RV&ndash;PA coupling indices were significantly more impaired in wtATTR-CM than in FD, and all three ratios demonstrated strong diagnostic performance in identifying wtATTR-CM. Although no single parameter outperformed the others, these findings indicate that RV&ndash;PA coupling assessment may have an added value in the differentiation of wtATTR-CM from FD compared to RV function parameters not normalized to load.</span></span></span></p>