P869 Effect of transcatheter MitraClip implantation on exercise performance evaluated by CPET
Authors: Han E , Oeztuerk B , Rettl R , Bergler-Klein J , Bonderman D , Badr Eslam R 
Published: January 2020

Abstract

Background & Purpose
Transcatheter MitraClip (MC) implantation has become the most frequently used percutaneous technique to treat severe mitral regurgitation (MR) in patients with high surgical risk. The assessment whether transcatheter MC implantation is the most suitable procedure on each individual patient is done primarily by 2D transthoracic echocardiography (TTE) as well as transesophageal echocardiography (TEE). In this case of a 79-year-old male multimorbid patient with cardiac amyloidosis and severe MR, different imaging modalities were used to assess the heart before and after MC implantation. The dynamic response of the heart after transcatheter MC approach was evaluated by comparing the patient’s exercise capacity before and after treatment with cardiopulmonary exercise testing (CPET).

Methods
Total body bone scintigraphy, 714 MBq 99m-Tc DPD, was performed to confirm the diagnosis of cardiac transthyretin (ATTR) amyloidosis. The extent of mitral regurgitation was assessed using TTE and TEE before and after MC implantation. Coronary angiography and right heart catheterization were performed prior to MC implantation. CPET by a cycle ergometer was used to measure the dynamic response of the heart before and after the procedure. A ramp protocol, adapted to reach maximal capacity after 8-10 min was chosen for the test. The parameter of main interest was maximal oxygen uptake (VO2 max, ml/min), the major factor known to limit exercise capacity.
Results
Bone scan showed tracer accumulation in myocardial tissue, genetic testing was negative which confirmed wild type cardiac transthyretin (ATTR) amyloidosis. Significant coronary artery disease was excluded by coronary angiography. Right heart catheterization disclosed post capillary pulmonary hypertension: mean pulmonary artery pressure of 42 mmHg and mean pulmonary capillary wedge pressure of 25 mmHg and end-diastolic pressure of left ventricle of 118 mmHg. A high grade left ventricular concentric hypertrophy (IVS = 26mm) with slightly reduced left systolic function, a severe MR (EROA = 35 mm2) and enlargement of left and right atria (LA = 68mm, RA = 68mm) were demonstrated by TTE. In TEE left atrium including left atrial appendage were free from thrombi; high grade left ventricular hypertrophy, restriction of posterior leaflet and severe MR with eccentric jet with dilated annulus were demonstrated. CPET before MC implantation: VO2 max 1299 ml/min (83% of predicted peak oxygen uptake value). MC implantation was performed with no post-procedural complications. Follow-up CPET showed higher VO2 max 1373 ml/min compared to the data before MC implantation (88% predicted peak oxygen uptake value).

Conclusions
TTE and TEE are the most common and accurate imaging modalities to evaluate MR regarding MitraClip evaluation. After the MC procedure the dynamic response of the heart can be observed by CPET with VO2 as a surrogate marker for heart function.
Abstract P869 Figure. a.b. TEE prior to MC, c.d. TEE after MC