Introduction:
Heart failure (HF) due to dilated cardiomyopathy (DCM) is a complex syndrome in which numerous cellular, mechanical and flow processes/interactions become deranged. Insights into derangement of left ventricular intra-cardiac flow patterns and kinetic energy (KE) are now afforded by the use of 4D flow CMR. Previous studies have found derangements of intra-ventricular flow components and KE within DCM patients compared to healthy volunteers.
Hypothesis:
We hypothesised that increasing derangement in 4D flow measures would relate to: 1) decreased mechanical cardiac function, as assessed by myocardial strain, 2) increased levels of biochemical remodelling markers and 3) worsening patient symptoms and functional capacity.
Methods:
26 idiopathic DCM patients (69% male, mean age 55±2 yr, LVEF 35±2%) and 10 controls (70% male, mean age 57±4yr, LVEF 68±1.2%) were assessed with 3T CMR.
Results:
The LV volume was divided into 4 functional components; direct flow (DF), delayed ejection flow (DEF), retained inflow (RI) and residual volume (RV). Compared to controls DCM’s had significantly decreased DF (11±1% vs 38±2%) and increased RV (51±2% vs 31±1%) (fig a). The KE at end diastole differed significantly for all flow components between groups (fig b).
Circumferential strain was significantly impaired in DCM’s vs controls (-9.9±0.8% vs -19.7±0.5%, p<0.0001). DF KE correlated positively to the 6 minute walk test (6MWT) and strain, and negatively to the Minnesota HF questionnaire and BNP (fig c).
Conclusions:
DCM patients demonstrated less efficient blood flow patterns and deranged KE profiles. The greater the derangement of flow parameters from normal, the worse the myocardial strain, BNP, 6MWT and patient symptoms. This study suggests that flow parameter derangements are novel biomarkers of disease severity in DCM, correlating with established markers of prognosis such as BNP and 6MWT and may become useful in monitoring novel therapies and predicting prognosis.
Impact of Age and Diastolic Function on Novel, 4D flow CMR Biomarkers of Left Ventricular Blood Flow Kinetic Energy