|
The IAC Standards
and Guidelines |
Click here for a printer-friendly PDF of the Vascular
Testing Standards |
Introduction: Facilities must
be accredited in the testing areas for which screening will be provided.
6.1B Screening
examinations are performed to determine the presence or absence of peripheral
vascular, cerebrovascular disease or to evaluate risk for cardiovascular or
cerebrovascular events in participants without specific signs or symptoms.
6.1.1B Screening
guidelines for the appropriate selection of participants should be based upon
contemporary scientific publications.
6.1.2B Screening
cannot replace diagnostic examinations for symptomatic individuals.
6.2B Equipment
must provide accurate data.
6.2.1B Imaging
Equipment – Duplex ultrasound with color flow Doppler must be
provided with:
6.2.1.1B imaging
frequencies appropriate for the structures evaluated;
6.2.1.2B Doppler
frequencies appropriate for the vessels evaluated;
6.2.1.3B range-gated
spectral Doppler with the ability to adjust the depth and position of the range
gate within the area of interest;
6.2.1.4B a
Doppler angle which is measurable and adjustable;
6.2.1.5B a
visual display and a permanent recording of the image;
6.2.1.6B a
visual display, an audible output, and a permanent recording of the Doppler
waveform and corresponding image which includes the Doppler angle.
6.2.2B Continuous
wave (CW) and pulsed wave (PW) Doppler (if used for testing) must be provided
with:
6.2.2.1B
a direction sensitive Doppler blood flow meter;
6.2.2.2B
Doppler transducer frequencies appropriate for the vessels evaluated;
6.2.2.3B
Doppler waveform display demonstrating bidirectional flow;
6.2.2.4B
an audible output and a permanent recording of the waveform;
6.2.2.5B
cuffs of varying widths appropriate to the limb segment to be evaluated.
6.3B Each
screening examination performed must have a written protocol. The protocol must
include:
6.3.1B equipment
to be used for each examination;
6.3.2B the
elements of proper technique (also see STANDARD
– Techniques);
6.3.3B the
anatomic extent that constitutes a screening examination;
6.3.3.1B Bilateral
testing is considered an integral part of a screening examination.
6.3.4B the
documentation that must be acquired for Screening examinations and the
additional documentation that must be acquired to describe abnormalities, if
present (also see STANDARD –
Documentation); and
6.3.5B a
description of how color Doppler or other flow imaging modes (e.g., power
Doppler) are used to supplement grayscale imaging, spectral Doppler and
velocity measurements.
6.4B
Vascular screening examinations must be interpreted and reported by the Medical
Director or a member of the medical staff of the screening service.
6.5B
Appropriate techniques must be used for screening exams to assess the presence
or absence of any abnormalities.
6.5.1B
Elements of proper technique include, but are not limited to:
6.5.1.1B
performance of an examination according to the facility specific, written
protocol;
6.5.1.2B
proper patient positioning;
6.5.1.4B
appropriate equipment and transducer selection;
6.5.1.5B
appropriate transducer positioning;
6.5.1.6B
proper sample volume size and positioning;
6.5.1.7B
optimization of equipment gain and display settings;
6.5.1.8B
a spectral Doppler angle of 60 degrees or less with respect to the vessel wall
and/or direction of blood flow when measuring velocities;
6.5.1.9B
proper measurement of spectral velocities as required by the protocol;
6.5.1.10B
identification of vessels by imaging and Doppler;
6.5.1.11B
use of computerized assisted electronic calipers or semiautomatic edge
detection software for CIMT measurements;
6.5.1.12B
ankle brachial index (ABI):
i.
measurement of upper extremity (brachial artery) systolic pressures must be
obtained from both arms and the higher of the two pressures used to calculate
the ABI;
ii.
measurement of ankle systolic pressures must be obtained bilaterally from the
distal posterior tibial (PT) artery and distal anterior tibial (AT)/dorsalis
pedis (DP) artery and the higher of the two pressures on each side used to
calculate the ABI.
6.6B
Each screening examination must provide sufficient documentation to allow
proper interpretation including, but not limited to:
6.6.4B
other measurements or images as required by the screening protocol.
6.7B
Vascular screening examinations are interpreted and reported by the Medical
Director or a member of the medical staff of the screening service.
6.8B
A final screening report or document that describes the results of the
examination findings and recommended follow-up must be provided to the
participant and/or participant’s physicians.
6.9B
Extracranial Cerebrovascular Screening
6.9.1B
Spectral Doppler waveforms and velocity measurements must be documented as
required by the protocol and must include at a minimum:
i.
One site in the proximal internal carotid artery with peak systolic and end
diastolic velocity measurements.
6.9.1.2B
Abnormal Examination:
i.
Peak systolic and end diastolic velocity measurements documenting area(s) of
significant findings in accordance with the screening diagnostic criteria.
6.10B
Carotid Intima-Media Thickness (CIMT) Screening
Comment: CIMT has been effectively used as
a marker of atherosclerosis in many patient populations and has also been used
as a primary endpoint demonstrating therapeutic efficacy with different
pharmacologic therapies. Studies using CIMT to make treatment decisions based
on a single IMT measurement, with documentation of the outcome for specific
interventions, for individual patients, are lacking. The IAC does not advocate
use of carotid IMT as a screening method for atherosclerotic risk until further
peer-reviewed literature evolves. If providers choose to perform CIMT testing,
rigorous methodological protocols should be strictly followed.
6.10.1B
Long axis grayscale images must be documented as required by the protocol and
must include at a minimum:
6.10.1.1B
measurements obtained during end diastole from at least three longitudinal
imaging planes (optimal and two complementary imaging planes – anterior,
lateral or posterior to the optimal angle);
6.10.1.2B
measurements from the far wall of the distal 1-2 cm of the CCA. Measurements
may also be obtained from the near wall of the CCA segment, as well as the near
and far wall of the bifurcation and the proximal 1 cm of the ICA.
6.10.1.3B
when plaque is present, characterization and/or dimensions.
6.11B
Peripheral Arterial Screening
6.11.1B
Ankle brachial index (ABI):
6.11.1.1B
bilateral brachial artery systolic pressures;
6.11.1.2B
bilateral ankle systolic pressures from the distal posterior tibial (PT) artery
and distal anterior tibial (AT)/dorsalis pedis (DP) artery.
6.12B
Abdominal Aorta Aneurysm Screening
6.12.1B
Grayscale images must be documented as required by the protocol and must
include at a minimum:
i.
One transverse image (defined as perpendicular to the long axis of the aorta)
with the single widest outer wall to outer wall diameter measurement.
6.12.1.2B
Abnormal Examination:
i.
One Transverse image (defined as perpendicular to the long axis of the aorta)
with the single widest outer wall to outer wall diameter measurement.
ii.
One Transverse image (defined as perpendicular to the long axis of the aorta)
with the single widest outer wall to outer wall diameter measurement of a
non-dilated segment for comparison.
6.13B
Records must be maintained that permit evaluation of annual procedure volumes.
These records must include information on:
6.13.1B
indication for the examination;
6.13.2B
examination(s) performed;
(See Guidelines below for further recommendations.)
6.13B
The annual procedure volume should be sufficient to maintain proficiency in
exam techniques and interpretation.
•
In general, a facility should perform a minimum of 50 (25 for CIMT) screening
examinations per testing section annually.