Achieving angiographic diagnosis

Access:

Tailor to the planned intervention. Diagnostic angiography for peripheral vascular disease is traditionally performed from the symptomatic leg unless the femoral pulse is absent or very weak. This ensures optimal images of the affected side. Straight catheters can be pulled back into the external iliac artery for single-leg views. There is no risk to the asymptomatic limb.

Catheterization:

Position the catheter below the renal arteries.

Runs:

Tailor the examination to the individual patient.

Supplemental views:

Additional views are frequently required pre- and post-intervention or in the presence of prosthetic joints; the answer is almost always an alternative projection, either an oblique view or a lateral. Adjunctive manoeuvres, such as flexion of the contralateral leg in a patient with a knee joint prosthesis, will help achieve an unimpeded lateral view ( Fig. 45.2 ).

Tip

Remember the diagnostic maxim: one view is one view too few. We are trying to visualize 3D structures. If in doubt, try another run at 90 degrees to the original.

Iliac obliques

The iliac vessels are tortuous and oblique views are essential to allow full assessment before and after intervention and also to demonstrate the origins of the internal iliac arteries in profile.

Tip

Remember to use the contralateral oblique view, e.g. LAO for the right iliac system.

Access:

Use ultrasound guidance to target puncture, use Table 45.3 as a guideline for choosing the point of access.

Catheterization:

The majority of at-risk grafts will be infra-inguinal, and antegrade puncture is usually required. Most grafts come off the common femoral artery (CFA) anteriorly and steep ipsilateral anterior oblique views are useful to profile their origins and to guide selective catheterization ( Fig. 45.4 ).

Runs:

A satisfactory angiogram must show the graft inflow and run-off and include views of the proximal and distal anastomoses in profile ( Figs. 45.4 and 45.5 ). Magnified oblique views should be used to demonstrate stenoses. When imaging vein grafts, demonstration of contrast jetting as a result of valve cusps requires runs at 6 frames per second (FPS). These should be viewed with a wide contrast window ( Fig. 45.6 ).

Tip

The Doppler is right! If the lesion cannot be identified at angiography, wheel in an ultrasound machine and re-scan to mark the lesion.

Difficulty inserting the sheath:

Review the basic principles of vascular access.

Difficulty catheterizing the graft origin

Once you have chosen the optimal projection, use roadmap or fluoroscopy fade for guidance. A shaped catheter, usually a Berenstein, Cobra or RDC, can be directed towards the graft origin.

Difficulty visualizing the graft origin

Contrast in the CFA patch, the stump of the SFA or in the PFA may obscure the graft origin. Position the catheter with its tip in the proximal graft; contrast can then be refluxed to show the graft origin. A frame rate of ≥2 FPS is necessary. Laterally running grafts are best shown with the ipsilateral posterior oblique view.

Access:

Diagnostic angiography is usually performed from the femoral approach. Therapeutic intervention is often easier from the brachial artery or with combined femoral and brachial access.

Catheterization:

Use a pigtail catheter for arch aortography. A Berenstein catheter will engage the vast majority of arch vessels if used properly.

Runs:

Begin with an arch aortogram to show the origins of the great vessels. Additional views may be needed to show the proximal subclavian arteries, particularly when they are tortuous. In suspected TOS, perform runs with the arms raised above the head and also in the Roos position (elbow flexed 90 degrees, shoulder abducted 90 degrees and dorsiflexed). It is possible to see as far as the elbow from an arch injection; a selective catheter should be advanced peripherally to image the distal arm vessels. Use iso-osmolar contrast when imaging the digital arteries. Remember that the radial and ulnar arteries often arise from the axillary or brachial arteries; failure to recognize this will lead to misinterpretation.

Tip

To obtain high-quality images of the digital arteries, invert the C-arm and place the hand on the image intensifier, immobilizing it with a sandbag. Use a vasodilator to increase flow and discriminate fixed lesions from spasm ( Fig. 45.7 ).

Unable to catheterize an arch vessel

• Remember the basic rules; identify the target vessel on an overview.

• If the arch is unfolded, the Berenstein catheter may be difficult to control; try using a Headhunter 1 catheter, which has a wider primary curve.

• If the target vessel is angulated backwards, then a reverse curve catheter, such as a Sidewinder may be helpful.

Poor visualization of the distal vessels

• Use a vasodilator to increase flow and also to discriminate spasm from irreversible fibrosis.

• Use iso-osmolar contrast and try increased contrast strength.

• Selectively catheterize and advance the catheter into a peripheral position.

Catheterization:

Position the pigtail catheter in the ascending aorta just above the aortic valve.

Runs:

A 30 degree LAO to show aortic arch and origin of the great vessels (centre on the aortic arch); a 60 degree LAO may be helpful during stent grafting and in trauma cases ( Table 45.5 ).