RADial Access Research: echo based radial artery evaluation for diagnostic and therapeutic coronary procedures

Invasive diagnostic angiography and percutaneous coronary intervention (PCI)
are essential pillars in contemporary cardiology. Patients with a wide spectrum
of clinical presentations from stable angina to unstable coronary syndromes
including acute ST-elevation myocardial infarctions are exposed to these kinds
of procedures. Since its introduction in 1977 multiple iterations have refined
the PCI technique into a safe procedure with low clinical adverse event rates.
For years the common femoral arteries were the access site of first choice for
these invasive procedures. Sheath size, anti-thrombotic regimen, acuity and
patient related characteristics (vessel size, obesity, gender*) have been
identified as predictors for procedure related vascular complications. Vascular
complications, bleeding complications and need for Red Blood Cell transfusions
are linked to short and longer-term mortality. The radial artery is an
alternative access site with less vascular and bleeding complications. After
confirmation of ulnar artery patency suggesting an intact palmar arterial arch
(with the Allen*s test) the radial artery is eligible for catheterization.
However coronary diagnostic and interventional procedures through radial access
can be more challenging. In up to 5-10% of radial cases the procedure needs to
be aborted with cross-over to the femoral route because of radial artery spasm.
Late radial artery occlusion occurs in 0.6 to 12% of cases potentially leading
to functio laesa of the hand involved.

To assess structural changes in the radial artery wall 3 hours and 30 days
after catheterization with a 6 F sheath for diagnostic or interventional
coronary procedures and elucidate arterial healing patterns that might explain
early radial artery spasm, late radial artery occlusion or loss of radial
artery pulsation precluding future arterial punctures and sometimes leading to
localized pain and functional impairment.

This is a single-center prospective observational study, which will include
approximately 100 patients who will undergo a diagnostic or interventional
coronary procedure through radial artery access.
After enrolment in the study protocol patients will undergo two-dimensional
vascular imaging and color Doppler ultrasonic assessment with a Siemens 7-10Mhz
linear probe and with the very-high resolution ultrasound Visualsonics Vevo®
2100 echo machine and a Visualsonics MS550D 22-55 Mhz probe. The rationale to
use the very high resolution device is to obtain advanced and detailed imaging
of the radial artery wall which is not reliably imaged by conventional high
resolution echo systems.

Two experienced technicians (JL and KW) will perform the ultrasound
examinations at baseline before radial artery cannulation, 3 hours after
arterial sheath removal and 4-6 weeks after the procedure. Whenever clinically
indicated, follow up visits and additional imaging will be organized.
A pre-specified battery of measurements will be prospectively collected in a
dedicated database.

At each time point a clinical assessment will be performed to assess the
puncture site specifically focusing on presence of
• any subjective discomfort
• functional impairment
• radial pulse.

All patients who participate in the study will undergo a non-invasive
echographic assessment of the radial artery before the procedure, 3 hours after
catheter removal and 30 days after the procedure. The echo assessment takes
approximately 20 minutes.