Myocardial Effects in Patients With ATTRv With Polyneuropathy Treated With Patisiran or Vutrisiran

Longitudinal relaxation time (T1) is the process by which the net magnetization (M) grows/returns to its initial maximum value (Mo) parallel to Bo in a MRI.

Myocardial T1 depends on the pulse sequence, cardiac cycle as well as other factors and increases at higher magnetic field strength. T1-mapping can detect a variety of myocardial pathologies, where it shows increased values. Because of variations between scanners the primary use of a local reference range is recommended and if a local reference range is not available quantitative results should not be clinically reported. An intermediate analysis will be done at 12 months

Kansas City Cardiomyopathy Questionnaire is a self-administered questionnaire developed to independently measure the patient's perception of their health status, which includes heart failure symptoms, impact on physical and social function, and how their heart failure impacts their quality of life. Five scores are generated, all scores are scaled 0-100, where 0 denotes the lowest reportable health status and 100 the highest. An intermediate analysis will be done at 12 months

The COMPASS-31 (Composite Autonomic Symptom Score-31) scale measures neurodegenerative system symptoms through 31 patient-reported questions. Assessment is through six weighted domains: orthostatic intolerance [10 points]; vasomotor [6 points]; secretomotor [7 points]; gastrointestinal [28 points]; bladder [9 points] and pupillomotor [15 points]. A higher score indicates worse autonomic dysfunction. An intermediate analysis will be done at 12 months

The 6 Minute Walk Test is a sub-maximal exercise test used to assess aerobic capacity and endurance. The distance in meter covered over a time of 6 minutes is used as the outcome by which to compare changes in performance capacity. An intermediate analysis will be done at 12 months

The Perugini grading scale is a semi-quantitative method of scoring cardiac uptake following injection of 99mTc-DPD, 99mTc-Pyrophosphate or 99mTc-HMDP scintigraphy in the investigation of cardiac amyloidosis (particularly ATTR amyloidosis). The grading scale visually compares tracer uptake in the myocardium and ribs.

grade 0 is no cardiac and normal rib uptake; grade 1 is cardiac less than rib uptake; grade 2 is cardiac equal to rib uptake; and grade 3 is cardiac greater than rib uptake with mild/absent rib uptake. An intermediate analysis will be done at 12 months

global longitudinal strain is a simple parameter in echocardiography to analyse atrial function abnormalities expressed in percentage that expresses longitudinal shortening as a percentage (change in length as a proportion to baseline length) for left ventricular (LV) systolic dysfunction. An intermediate analysis will be done at 12 months

Global left atrial longitudinal strain is a parameter of echocardiography to analyse atrial function abnormalities expressed in percentage. An intermediate analysis will be done at 12 months

Global strain of the right ventricular free wall of echocardiography to analyse right ventricule function expressed in percentage. An intermediate analysis will be done at 12 months

Myocardial work is composed of 4 parameters to assess myocardial function using echocardiography. An intermediate analysis will be done at 12 months

Global Constructive Work (expressed in mmHg%) : Positive work performed in systole (shortening) + Negative work performed in isovolumetric relaxation (lengthening). Normal range : 1582-2881

Global Wasted Work (expressed in mmHg%) : Negative work performed in systole (lengthening) + Positive work performed in isovolumetric relaxation (shortening). Normal range : 226 ± 28

Global Work Efficiency (expressed in %) Percentage (0-100%) of constructive work over total work => Constructive work/(constructive work + wasted work). Normal range : 91 ± 0.8

Global Work Index (expressed in mmHg%) : Amount of myocardial work performed by the left ventricle during systole => area of PSL from mitral valve closure to mitral valve opening. Normal range : 1292-2505