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P3804Left ventricular wall thickness measured with computed tomography predicts mitral regurgitation improvement in patients implanted with cardiac resynchronization therapy


 
 
 Secondary mitral regurgitation (MR) is common in heart failure (HF) patients and results in progressive left ventricular (LV) dilatation, papillary muscle (PM) displacement and mitral valve leaflet tethering. In selected HF patients, cardiac resynchronization therapy (CRT) has been proved to reduce MR by LV reverse remodeling, resynchronization of PM insertion site contraction and reduction in MV tenting area and inter PM distance. However, data regarding the impact of LV wall thickness (WT) on MR improvement are scarce.
 
 
 
 In this prospective study, a total 54 patients scheduled for CRT, underwent pre procedural CT. Reduced LV WT was defined as WT<6mm and was quantified as a percentage of total LV area. LV was segmented in 17 segments to assess the number of LV segments with reduced WT. End point was 6-month echocardiographic MR improvement by ≥1 class. For this analysis, we focused on patient with mild (class 2) to severe (class 4) MR.
 
 
 
 Among the 54 patients, 38 (70.4%) had mild to severe MR at baseline and a total of 16 (42.1%) experienced MR improvement by ≥1 class at 6 months. there was no difference regarding the co-morbidities, electrocardiogram and echocardiographic parameters between patients with or without MR improvement. However, patients without MR improvement had significant higher NT-pro BNP level at baseline. Interestingly, patients without MR improvement had larger LVWT <6mm area (41.541.5±19.4 vs. 22.4±16.1%, p=0.003) associated with higher number of papillary muscle (PM) inserted in reduced LV WT area. In multivariate analysis, an area ≥25% of LVWT<6mm including at least 1 PM insertion was the only predictor of no MR improvement at 6 months (HR 18.4 (1.25–271.75), p=0.034). Lastly, patients with MR improvement had significant lower rate of basal segments with reduced WT, especially in the lateral location. Of note, patients with MR improvement exhibited fewer rate of postero-lateral WT <6mm segments.
 Left ventriculat segmentation
 
 
 
 LV WT evaluated using CT is a strong predictor of no MR improvement in HF patients with mild to severe MR and who scheduled for CRT implantation.
