Dobutamine Stress Echocardiography in LF/LG Aortic Stenosis and Wild-type Transthyretin Amyloid Cardiomyopathy

Summary

The goal of this prospective clinical study is improve the diagnosis of Low-flow low-gradient aortic stenosis (LF/LG AS), in patients with co-existing wild-type transthyretin cardiac amyloidosis (ATTRwt). The main question it aims to answer is whether the classic dobutamine-stress echocardiography can be used to determine AS severity in patients with ATTRwt and LF/LG AS This question will be tried to answer by comparing dobutamine stress echocardiography, with the invasively measured aortic valve area (which is considered as the gold standard). In addition we aim to assess the degree of myocardial fibrosis and amyloid infiltration, assessed by light microscopy and cardiac magnetic resonance (CMRI) and evaluation of myocyte mitochondrial function by high resolution respirometry and their relation to AS severity and hemodynamic response to dobutamine.

Eligibility

Inclusion Criteria:

1. ATTRwt, diagnosis confirmed by 99mtc-3,3-Diphosphono-1,2-Propanodicarboxylic Acid (DPD) scintigraphy, genetic testing, and/or endomyocardial biopsy.
2. Symptomatic patients (New York Heart Association \> class I) treated with loop diuretics.
3. LF/LG AS: Defined as, aortic valve area ≤ 1 cm2 and mean gradient \< 40 mmHg, and SVI ≤35 ml/m2.
4. Age ≥ 65 years.
5. Oral and written informed consent.

Exclusion Criteria:

1. Other significant valvular disease.
2. Known severe coronary artery diseases: left main stem stenosis or 3-vessel disease, or recent acute myocardial infarction (\< 4 weeks).
3. Contraindications to the use of dobutamine: Known allergy to dobutamine or sulfite, phaeochromocytoma or ventricular tachycardia (VT).

Conditions3

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