Left ventricular blood flow kinetic energy is associated with the six-minute walk test and left ventricular remodelling post valvular intervention in aortic stenosis.

Alaa Elhawaz,Peter Braidley,Steven Hunter,Pankaj Garg,Andrew J Swift,Gareth T Archer,James M Wild,Rachel Jones,Ever Grech,Norman Briffa,Ian R Hall,Benjamin Fidock,Julian P Gunn,Abdallah Al-Mohammad,Alexander Rothman,Rob J Van Der Geest,Rod Hose,Natasha Barker,Hamza Zafar

doi:10.21037/qims-20-586

Abstract

Left ventricular (LV) kinetic energy (KE) assessment by four-dimensional flow cardiovascular magnetic resonance (4D flow CMR) may offer incremental value over routine assessment in aortic stenosis (AS). The main objective of this study is to investigate the LV KE in patients with AS before and after the valve intervention. In addition, this study aimed to investigate if LV KE offers incremental value for its association to the six-minute walk test (6MWT) or LV remodelling post-intervention. We recruited 18 patients with severe AS. All patients underwent transthoracic echocardiography for mean pressure gradient (mPG), CMR including 4D flow and 6MWT. Patients were invited for post-valve intervention follow-up CMR at 3 months and twelve patients returned for follow-up CMR. KE assessment of LV blood flow and the components (direct, delayed, retained and residual) were carried out for all cases. LV KE parameters were normalised to LV end-diastolic volume (LVEDV). For LV blood flow KE assessment, the metrics including time delay (TD) for peak E-wave from base to mid-ventricle (14±48 vs. 2.5±9.75 ms, P=0.04), direct (4.91±5.07 vs. 1.86±1.72 µJ, P=0.01) and delayed (2.46±3.13 vs. 1.38±1.15 µJ, P=0.03) components of LV blood flow demonstrated a significant change between pre- and post-valve intervention. Only LV KEiEDV (r=-0.53, P<0.01), diastolic KEiEDV (r=-0.53, P<0.01) and Ewave KEiEDV (r=-0.38, P=0.04) demonstrated association to the 6MWT. However, Pre-operative LV KEiEDV (r=0.67, P=0.02) demonstrated association to LV remodelling post valve intervention. LV blood flow KE is associated with 6MWT and LV remodelling in patients with AS. LV KE assessment provides incremental value over routine LV function and pressure gradient (PG) assessment in AS.

Highlights

Aortic stenosis (AS) is the third most common cardiovascular disease in Western countries and the commonest valvular disease requiring valve replacement [1,2]
The main objectives of this study are: (I) to investigate the Left ventricular (LV) kinetic energy (KE) in patients with aortic stenosis (AS) before and after the valve intervention, (II) to investigate if the KE of the blood flow components can provide an insight into the haemodynamic of AS, and to study if LV intra-cavity blood flow KE (LV KE) in patients with AS is associated with quantitative physical endurance evaluated by the six-minute walk test (6MWT)
SAVR patients were younger than TAVI patients (68±8 vs. 82±11 years old, P=0.01), and the 6MWT was better in SAVR patients as compared to TAVI cohort (409±182 vs. 318±96.5 meters, P=0.02)

Summary

Introduction

Aortic stenosis (AS) is the third most common cardiovascular disease in Western countries and the commonest valvular disease requiring valve replacement [1,2]. According to the current European Society of Cardiology (ESC) or the European Association for Cardio-Thoracic Surgery (EACTS) guidelines, the indications for aortic valve replacement depend on the patient’s symptoms and the severity of the stenosis [3]. It is often debated which treatment option should be offered to yield optimum results. This study aimed to investigate if LV KE offers incremental value for its association to the six-minute walk test (6MWT) or LV remodelling post-intervention. LV KE assessment provides incremental value over routine LV function and pressure gradient (PG) assessment in AS

Objectives

Methods

Results

Conclusion