A. Schmidt: Most SFA CTO crossing is performed via ipsilateral antegrade approach.
A. Schmidt: For multiple beneficial reasons, including shortening the distance from the access site to the CTO, enhancement of pushability, and much better wire and catheter torque.
J. Mustapha: Do you ever perform a contralateral access approach for SFA CTOs?
A. Schmidt: Yes, mostly in patients who are not good candidates for antegrade access such as obese patients, those with proximal disease, ostial SFA disease, or CTOs. Mostly, I prefer antegrade access for SFA CTOs.
J. Mustapha: Many of us have seen you perform live cases and have witnessed your excellent techniques in retrograde popliteal and SFA access in complex CTO crossing. Why do you access these segments?
A. Schmidt: We access distal to the CTO cap of the SFA or popliteal CTO only when we fail to cross from antegrade approach first. The reason we access close to the CTO is similar to the reasoning of the antegrade access, close to the CTO cap, which in turns helps with retrograde pushability and torqueability.
J. Mustapha: What advice would you give practitioners who would like to perform similar retrograde access in the SFA/popliteal?
A. Schmidt: Proceed with caution, as this should only be attempted after an antegrade approach fails. Be sure to have a balloon across the occluded target lesion and the guidewire across the distal access before taking the access catheter out, so that in case a problem (dissection, occlusion) occurs at the distal entrance, balloon angioplasty can be done to fix it. Hemostasis is principally done by external compression.
A. Schmidt: The time depends on the size of the access catheter or the sheath used. Most of the time, we use the smallest catheter possible, .018-inch to .035-inch. Therefore, we perform a three-minute balloon inflation followed by an angiogram.
A. Schmidt: Yes.
J. Mustapha: Do you worry about harming the stent after getting access in it?
A. Schmidt: No. So far, in our experience, we have not had any issues with stents in these situations. Keep in mind, we only get an access in the stent in extreme cases and place the smallest catheter possible.
J. Mustapha: Moving to retrograde tibial access, which access method do you use to enter the artery, angiogram-guided or ultrasound-guided?
A. Schmidt: We use angiogram-guided access.
J. Mustapha: Which is your preferred tibial artery for retrograde access and which part of the artery do you like to enter?
A. Schmidt: My preferred artery is the anterior tibial artery and I prefer to enter it proximally.
J. Mustapha: Why proximal versus distal?
A. Schmidt: Proximally, because the vessel diameter is larger and accommodates a 4 French sheath if needed.
J. Mustapha: How do you get the access?
A. Schmidt: First we position the foot supine and support it with a rolled-up towel, then perform an angiogram in left oblique 30° view, and enter the needle thru the skin into the artery. If no blood returns, we perform an oblique view with repeat angiogram which helps show the tip of the needle and artery.
J. Mustapha: How do you obtain hemostasis after the proximal tibial access?
A. Schmidt: Most of the time, we use an external blood pressure cuff. Occasionally, we use an intra-arterial balloon.
J. Mustapha: If needed, what are your tips and tricks for getting distal tibial access?
A. Schmidt: Starting with the dorsalis pedis access, foot positioning is important. First we position the foot supine and support it with a rolled-up towel, then the C-arm is positioned at about 15° ipsilateral and 10° cranial. We then use the quick access needle holder, followed with an angiogram. Also, we can puncture and perform contrast injection simultaneously, as needed.
J. Mustapha: Do you recommend road mapping for tibial access?
A. Schmidt: No, side movements of the artery due to puncture needles are not noticed, which may lead to accidental venous access and failed attempts. Also, I don’t recommend coming in from a lateral approach.
J. Mustapha: How do you know your needle is in line with the artery?
A. Schmidt: After angiogram is done, make the needle form one line with the artery (Figure 1A-B).
J. Mustapha: What do you do in the setting of no blood return?
A. Schmidt: Obtain oblique orthogonal views at 55-65°, load the guidewire into the needle, and perform contrast injection via the proximal sheath and pull back very slowly. Keep testing if the guidewire makes it through. Another method is to pull back slowly and inject contrast from the needle holder until you see contrast in the artery, then advance the guidewire (Figure 2A-G).
J. Mustapha: Any tips on how to get peroneal access?
A. Schmidt: Start with an anterior approach. Place the C-arm at ipsilateral LAO 30° (Figure 3A), perform antegrade angiogram, and position the needle in line with the artery. If no success, then move the C-arm to right anterior oblique (RAO) 70° (Figure 3B) and repeat angiogram. Redirect the needle toward the artery, puncturing the peroneal artery through the membrana interossea.
J. Mustapha: Which puncture site is safer?
A. Schmidt: The distal tibial access approach is safer, as it is not associated with compartment syndrome.
J. Mustapha: What needles to you use for proximal and distal tibial access?
A. Schmidt: For proximal anterior tibial, posterior tibial, and peroneal access, we use a 7cm, 21g needle. For distal tibials, we use a 4cm, 21g needle.
J. Mustapha: Please advise what NOT to do in infrapopliteal retrograde access.
A. Schmidt: One should not access communication arteries, especially those off of the peroneal artery, as shown in Figure 4.
J. Mustapha: How do you minimize radiation exposure?
A. Schmidt: My angiographical approach to retrograde pedal and tibial puncture is quick and precise, minimizing radiation exposure. I attribute this to experience and the right equipment (Figure 5A). I wear a ring dosimeter (Figure 5B) to measure my exposure.
Disclosure: Dr. Mustapha reports he is a consultant to Bard Peripheral Vascular, Covidien, Cordis, CSI, Spectranetics, and Boston Scientific. Dr. Schmidt reports occasional consulting for Bard and Medtronic.
Dr. Andrej Schmidt and Dr. J.A. Mustapha can be contacted at firstname.lastname@example.org.