Itamar Medical Ltd.
Endo
PAT
TM
x Device
2
Operation Manual
The Gold Standard for Endothelial Dysfunction evaluation, the Intra-coronary Acetylcholine
(Ach) Challenge method, is routinely performed at the Mayo Clinic.
According to the Intra-coronary Acetylcholine (Ach) Challenge method, a catheter is
positioned in the origin of the left main coronary artery and Ach is infused with incremental
concentration followed by coronary angiogram. The coronary artery diameter is measured in
the segment 5mm distal to the tip of a Doppler wire using a computer-based image analysis
system. Average peak velocity (APV) is derived from the Doppler flow velocity spectra and
coronary blood flow (CBF) is determined as:
*(coronary artery diameter/2)
2
*(APV/2).
Endothelium-dependent coronary flow reserve is calculated as percent change in CBF in
response to the Ach challenge.
Normal coronary endothelial function is defined as an increase in CBF of
>50% and an increase or less than 20% decrease in the coronary artery
diameter in response to the maximum dose of intra-coronary Ach (ΔCBF >
50% and ΔCAD > -20%)
[
Al Suwaidi J, Hamasaki S, Higano ST, Nishimura RA, Holmes DR Jr, Lerman A.
Long-term follow-
up of patients with mild coronary artery disease and endothelial dysfunction
.
Circulation
101:948-
954, 2000
]
Synopsis of Clinical Study Protocol:
Objectives:
To evaluate the EndoPAT
TM
2000 device relative to a gold standard procedure as a
diagnostic aid for detecting coronary endothelial dysfunction.
Methodology:
Patients, who had been referred to diagnostic angiography cardiac catheterization
laboratory for diagnostic angiography secondary to signs or symptoms of ischemic heart
disease and suspected coronary endothelial dysfunction and were found to have normal
or near to normal angiogram, underwent Intra-coronary Acetylcholine (Ach) challenge
test to assess attenuation in required increases to coronary blood flow (CBF) and coronary
artery diameter (CAD), where each of these parameters served as an indicator for coronary
endothelial dysfunction. Coronary endothelial dysfunction is diagnosed if one of the
following changes is observed in response to the Ach challenge test: ΔCBF ≤ 50% OR
ΔCAD ≤ -20%. Patients were then evaluated using the EndoPAT 2000, which measures
Peripheral Arterial Tone (PAT) signal changes at the fingertip, to a reactive hyperemia
challenge. The PAT signal is a measure of the digital pulsatile volume changes and is
measured with a non-invasive disposable PAT probe. The reactive hyperemia procedure
consists of a 3-10 minute baseline recording, 3-5 minutes of blood flow occlusion to one
arm using an lower arm blood pressure cuff, and 3-5 minutes of recording after cuff
release. The expected response is of a post occlusion increase of the PAT signal amplitude
and the PAT score is provided automatically by the system’s software and is basically the
ratio between the post- to pre- occlusion average signal size, corrected for systemic
changes and baseline level.
Planned Enrollment
: 100 patients
Actual Enrollment
: 111
Safety Analysis Cohort
: 110 (One patient withdrew consent)
Efficacy Analysis Cohort
: 94
Criteria for inclusion:
Patient Age > 17
