ISNVD Abstract Book

EVALUATION OF MUSCLE METABOLISM IN MULTIPLE SCLEROSIS:
A NEAR INFRARED SPECTROSCOPY-BASED APPROACH
Anna Maria Malagoni, MD, PhD, Michele Felisatti, PhD, Nicola Lamberti, BS,
Paolo Zamboni, MD, Fabio Manfredini, MD
Vascular Diseases Center, University of Ferrara, Italy
2nd Annual ISNVD Scientific Meeting
18-22 February 2012 (Orlando, Florida USA)
PURPOSE
•To determine muscle metabolism of gastrocnemius in a static phase
(oxygen consumption) and in a dynamic phase (oxygen changes during an
incremental treadmill test) in multiple sclerosis (MS) patients compared to
healthy subjects, and
RESULTS
rmVO 2
was significantly higher in all MS legs compared to healthy legs (P=0.01)
(Fig.1),
•To compare in MS patients the results of the dynamic test with the validated
6-minute walking test (6MWT).
INTRODUCTION
Near Infrared Spectroscopy (NIRS) allows a non invasive study of muscle metabolism
under static and dynamic conditions. NIRS based methods have been applied for
healthy and diseased people [1-4], but poorly in studies with MS patients.
Fig.1.Comparison of resting muscle oxygen
consumption between Healthy and MS
subjects
also analyzing separately PP and RR clinical types (P=0.004) (Fig.2).
MATERIALS AND METHODS
SUBJECTS
MULTIPLE SCLEROSIS (n=28)
HEALTHY (n=11)
Legs (n) 56 22
Sex (n) M=16; F=12 M=6; F=5
Age (years) 42.7±14.0 33.2±8.9
Clinical Types Relapsing Remitting (RR): N=19 -
Primary Progressive (PP): N=9
Disease duration (years) 9.9±6.3 -
EDSS 3.8±2.2 -
Fig.2.Comparison of resting muscle oxygen
consumption among Healthy and MS
clinical types
O 2
Hb AUC
, HHb AUC
, dHb AUC
, and tHb AUC
did not
differ between all MS and healthy legs but
different patterns of O 2
Hb AUC
related to PP
legs were highlighted with lower values
than healthy and RR legs (P=0.02) (Fig.3).
Fig.3.Comparison of oxygenated hemoglobin
(area under curve values) among Healthy
and MS clinical types
1) NIRS evaluation
a) Static measurement
Oxygen consumption (rmVO 2
) at gastrocnemius muscle
was measured at rest by venous occlusion [5].
b) Dynamic measurement
All healthy subjects and all
ambulatory MS patients (n=27)
performed an incremental level
treadmill test with NIRS probes on
the gastrocnemius muscle.
Protocol: starting speed set at 1.0
Km/h, increases of 0.1 Km/h every
10 m to exhaustion (maximal speed)
[4].
c) Data processing
Variations in oxygenated (HbO 2
),
deoxygenated (HHb), total (tHb=
HbO 2
plus HHb), and differential
(dHb=HbO 2
minus HHb) hemoglobin
were recorded and quantified as
area-under-curve (AUC) within the
speed range 1.0-2.0 Km/h [4].
Cardiovascular load
Heart rate was recorded during the
treadmill test, and the variation of
beats within the speed range 1.0-
2.0 Km/h was calculated (dHR).
2) Six Minutes Walking Test
a) Incremental treadmill test; b) NIRS
semiquantitative data; c) Transformation into
quantitative data by area-under-curve calculation
In MS ambulatory patients, indoor 6MWT was also
performed and the distance covered was assessed
(6MWD).
A significantly higher dHR
was observed in all MS
patients (P=0.0003) (Fig.5)
compared to healthy
subjects, also according to
both MS clinical types
(P