PhD Scientific Days 2022

Clinical Medicine I. (Poster discussion will take place in the Aula during the Coffee Break)

Echocardiographic assessment of the left atrium for categorization of left ventricular diastolic function in heart transplant recipients

Text of the abstract

Introduction: Echocardiographic assessment of left ventricular (LV) diastolic function remains challenging after heart transplant (HTx). However, its evaluation is of particular importance as diastolic dysfunction (DD) may reveal allograft rejection or vasculopathy. Left atrial strain (LAS) appears as a promising tool in categorizing diastolic function.
Aim: We aimed to evaluate the structural and functional characteristics of left atrium (LA) in determining LV diastolic function in adult HTx recipients.
Methods: We analyzed serum NT-terminal pro-brain natriuretic peptide (NT-proBNP) levels and transthoracic echocardiograms of 27 patients 1 and 4 months following HTx. To derive E/e’ ratio, we characterized mitral inflow velocities (v) by pulsed-wave Doppler and mitral annular v using tissue Doppler imaging. Peak velocity of tricuspid regurgitation (TR vmax) was obtained by continuous-wave Doppler. We evaluated LA volume index (LAVi) using biplane area-length method and LA reservoir, conduit and contractile function by speckle tracking-derived LAS. Data values were given as mean±standard deviation. Statistical analysis was performed using t-test or Spearman correlation after assessment of normality.
Results: Average E/e’ (11.9±4.3 vs. 8.7±2.1; p=0,004), septal e’ v (6.6±1.9 cm/s vs. 7.7±1.8 cm/s; p=0.045), lateral e’ v (11.2±2.8 cm/s vs. 13.7±3.1 cm/s; p<0.001) and TR vmax (2.7±0.3 m/s vs. 2.5±0.3 m/s; p<0.001) improved significantly over time. LAVi and LAS did not change significantly. LAS was reduced compared to normal values from the literature. NT-proBNP levels decreased significantly (8543±8413 pg/ml vs. 1000±846 pg/ml; p<0.001). There were no strong correlations between LA reservoir strain and TR vmax, septal or lateral e’ v, average E/e’, LAVi or NT-proBNP level.
Conclusions: Significant improvement of the guideline-recommended diastolic parameters independent of LA and decreased incidence of DD suggest that restrictive pattern of the graft subsides over time. Hence, LA structural and functional impairment cannot be assessed exclusively as secondary consequence of DD and elevated LV filling pressure but might be primary characteristics related to surgical techniques. Relevance of LAVi and LAS in determining LV diastolic function is limited after HTx.