Biventricular hemodynamic phenotyping of transthyretin amyloid cardiomyopathy vs. HFpEF: a pilot invasive pressure-volume loop analysis
F Edbom, A Venkateshvaran, E Tossavainen, H Hagstrom, B Pilebro, P LindqvistAbstract
Background
Transthyretin amyloid cardiomyopathy (ATTR-CM) is frequently misclassified as heart failure with preserved ejection fraction (HFpEF) owing to overlapping clinical and echocardiographic features. Although both conditions are characterized by restrictive ventricular physiology, conventional non-invasive imaging primarily reflects volumetric function and often fails to capture the underlying biventricular energetic and contractile abnormalities.
Purpose
We sought to characterize the comprehensive biventricular hemodynamic signature of transthyretin cardiac amyloidosis (ATTR-CM) using gold-standard invasive pressure–volume (PV) loop analysis with simultaneous left- and right-ventricular assessment.
Methods
Patients with confirmed ATTR-CM (n=2) and HFpEF (n=2) underwent invasive biventricular PV loop catheterization. Key hemodynamic indices, including end-systolic (ESPVR) and end-diastolic pressure-volume relationships (EDPVR), ventricular-arterial (V-A) coupling, and myocardial energetic efficiency (MEE) were calculated during steady state conditions. Load-independent indices were derived using inferior vena cava (IVC) occlusion.
Results
Despite comparable heart rates and stroke volumes, ATTR-CM was characterized by lower biventricular contractility, with a 66% lower LV ESPVR in ATTR-CM (1.6 vs. 4.5mmHg/mL) and 68% lower RV ESPVR (0.5 vs.1.4 mmHg/mL) compared to HFpEF. This difference in RV contractility was confirmed with a lower RV ESPVR slope (RV Ees) in ATTR-CM with preload reduction via Inferior Vena Cava occlusion (0.3 vs 0.8 mmHg/mL). ATTR-CM displayed 83% larger LV end-systolic volumes, lower LV & RV energetic efficiency (LV MEE: 58% vs. 72%, RV MEE 69% vs. 80%), and 85% higher ventricular-arterial mismatch (1.16 vs. 0.63). Interestingly, ATTR-CM exhibited 49% lower LV stiffness (LV EDPVR: 0.12 vs 0.23mmHg/mL).
Conclusions
Preliminary PV analysis suggests that ATTR-CM is hemodynamically distinct from HFpEF with impaired biventricular systolic reserve, ventricular-arterial mismatch and mechanical inefficiency. LV and RV contractility, assessed using pressure–volume–derived indices, represent a key mechanistic finding with direct clinical relevance. Comprehensive hemodynamic phenotyping may support precision therapy in ATTR-CM.Table study dataFor image description, please refer to the figure legend and surrounding text.Figure Pressure-Volume ATTR-CM vs. HFpEFFor image description, please refer to the figure legend and surrounding text.