Ask the Transradial Expert

Transradial/Transfemoral Retrograde CTO Revascularization

Orlando Marrero, RCIS, MBA, Tampa, Florida, Zaheed Tai, DO, FACC, FSCAI, Winter Haven Hospital, Winter Haven, Florida
Orlando Marrero, RCIS, MBA, Tampa, Florida, Zaheed Tai, DO, FACC, FSCAI, Winter Haven Hospital, Winter Haven, Florida

Question: Are you doing chronic total occlusions (CTOs) using radial access?

Answer: It depends on the patient and the approach (retrograde vs. antegrade, or both). We have previously described this.1-4 In our approach to CTOs, we utilize dual access. Radial access does offer the benefit of reduced access site bleeding, but essentially limits you to a 7 French (Fr) system. Therefore, in CTO cases, we will base access on our intended approach and need for guide support. The following case utilizes one femoral and one radial access. The patient had a recent complex peripheral revascularization performed, with some residual tenderness at the left radial site and left groin. 


A 62-year-old male with a previous history of tobacco abuse presented with new onset atrial fibrillation and cardiomyopathy. He underwent cardioversion to sinus rhythm and left heart catheterization for new-onset cardiomyopathy. Angiography demonstrated a CTO of the right coronary artery (RCA) as well as the distal left circumflex (LCX), with no involvement of the left anterior descending coronary artery (LAD). A subsequent stress test demonstrated ischemia in both territories without any involvement of the LAD. The patient also had peripheral vascular disease and had developed a right lower extremity ulcer requiring complex iliac intervention. Despite conversion to sinus rhythm and improvement in left ventricular (LV) function, he continued to have dyspnea on exertion, particularly now that he was ambulating more. Therefore, he presented for attempted revascularization of the RCA. After review of the angiogram, it was decided to first attempt recanalization of the RCA. Given the lesion length of > 20 mm and the proximal cap ambiguity, access was set up for a retrograde attempt as the initial approach.

The right groin was accessed with a micropuncture kit and a 5 Fr sheath was placed.  We upsized to an 8 Fr Destination sheath (Terumo) and used an 8 Fr LBU 3.5 90 cm guide (Boston Scientific) to engage the left system. The right radial artery was accessed with a Glidesheath Slender (Terumo), then upsized for a 7 Fr sheath. We initially tried an Amplatz left (AL) 75 guide from the right, but it seemed too big, and so we switched to a Judkins right (JR) 4 (Boston Scientific) guide to engage the RCA. Angiography demonstrated, as previously reported, a CTO of the RCA. The RCA was 100% occluded after the conus branch, without evidence of right-to-right collaterals. There were left-to-right collaterals demonstrating reconstitution at the bifurcation of the posterior descending artery (PDA) and posterior left ventricular branch (PLV), with some angiographic disease evident at the bifurcation. No further retrograde filling was noted.

Given the patient’s angiographic findings, we initially took a retrograde approach. Heparin was administered to an activated clotting time (ACT) > 300; a 150 cm Corsair catheter (Asahi) was then advanced over a workhorse wire (Runthrough, Terumo) to selectively engage the second large septal, which from the diagnostic angiogram appeared to have a direct communication (Figure 1). A Fielder XT wire (Abbott Vascular) was then used to cross the septal into the distal PDA. Unfortunately, we were unable to find a direct communication from the septal to the PDA. The catheter was then directed to the more proximal first septal and entered into a branch that appeared to go toward the PDA; however, on angiography, the wire was not communicating. We therefore redirected with the Fielder XT, switched to a Fielder FC (Asahi) with a small secondary bend, and entered into the distal PLV branch. We were able to advance the 150 cm Corsair catheter through the septal (Figure 2) into the distal PLV, but multiple attempts to go retrograde into the RCA (initially with the Fielder FC, then a Pilot 200 wire [Abbott Vascular]) resulted in deflection into the PDA. We elected to pull back and search for a different septal branch that communicated directly with the PDA, hoping that a different septal branch would give a better approach to the distal cap.

Unfortunately, multiple attempts were unsuccessful in engaging another septal. We rewired the previous septal into the PLV, re-advanced the Corsair catheter, and this time, advanced the Corsair catheter toward the cap. A MiracleBros 3 wire (Abbott Vascular) was used to “scratch” the distal cap (Figure 3) and we advanced retrograde into the vessel. At this point, we switched out for a Pilot 200 wire that was able to advance retrograde toward the proximal cap. The Corsair did not advance to the crux, most likely secondary to “Corsair fatigue”. We trapped the Corsair with a 3.0 mm x 20 mm Emerge balloon (Boston Scientific) in the left guide and removed it, leaving the Pilot 200 wire retrograde in the RCA. We re-advanced a second Corsair catheter that gave us more purchase retrograde in the vessel, but the Pilot 200 still could not penetrate the proximal cap. We switched to a Confianza 12 Pro (Asahi) (Figure 4) that allowed us to navigate through the proximal cap and into the antegrade guide (Figure 5). The Confianza wire was then trapped in the 7 Fr guide with a 2.5 mm x 20 mm Emerge balloon (Figure 6), and using this as a rail, we advanced the Corsair catheter retrograde into the guide. 

We switched out to a Viper wire 335 with a .014-inch tip (CSI, Inc.) dripping RotaGlide lubricant (Boston Scientific) into the Corsair (pink lady*). The wire was externalized through the right radial artery (Figure 7) and the Corsair was backed out into the PLV.  A 0.9 mm laser (Spectranetics) at a setting of 45/40 (Figure 8) was used to perform laser atherectomy to the entire RCA, down to the bifurcation or just short of it, as it would appear from a retrograde angiogram. Approximately 30 to 35 seconds of laser atherectomy was performed. We advanced a 2.5 mm x 30 mm Emerge balloon and dilated the RCA. There did not appear to be sufficient flow into the PDA or PLV at this point. We stented distal to proximal, stenting the entire RCA from the bifurcation to the ostium, using a 2.75 mm x 38 mm, 3.0 mm x 38 mm, and a 3.5 mm x 20 mm Promus Premier drug-eluting stent (Boston Scientific) (Figure 9).

We had good flow to the native RCA without compromise of the conus branch or right ventricular (RV) marginal branch, but did not have good flow into the PDA and PLV. We then managed to wire the PDA from an antegrade approach with a Fielder FC wire. With the Viper wire already in the PLV from the retrograde approach, we performed a kissing balloon inflation with two 2.0 mm x 20 mm Emerge balloons, resulting in slightly improved flow into both vessels. A second inflation was done slightly more distal, with very good flow noted in the PLV. There appeared to be a dissection in a distal branch, most likely from a retrograde approach, but it was of a small caliber and not flow limiting to the majority of the PLV. However, a visible dissection was noted at the PDA and distal RCA at the bifurcation. We wired the PLV from an antegrade approach, re-advanced the Corsair catheter into the antegrade guide, and removed the Viper wire through the catheter, protecting the septals. The Corsair was then backed out through the left system, removing all equipment from the left system.

A 2.5 mm x 20 mm Promus Premier drug-eluting stent was planned, with placement from the bifurcation into the PDA, particularly since the ostium of the PLV did not seem to have any disease. The PLV wire was pulled back and the bifurcation into the PDA was stented, with resulting TIMI-3 flow into the PDA and PLV. Just beyond the stent in the distal PDA, there was a questionable dissection. A 2.5 mm x 20 mm Emerge balloon was used for a low-pressure (3 atmospheres) inflation for 2 minutes. Final angiography demonstrated brisk TIMI-3 flow in the RCA, without dissection, perforation or embolization in the body of the vessel (Figure 10). A small branch of the PLV had a non-flow-limiting dissection, but no evidence of perforation or embolization was noted. The patient was discharged the following morning. He will be evaluated as an outpatient regarding circumflex revascularization. 


Chronic total occlusions occur in approximately 20-30% of patients referred for coronary angiography.5,6 Despite its common occurrence, CTO recanalization is only attempted 10-15% of the time.7 Historical success rates are between 50-70%, despite being performed in select cases.7-10 The hybrid algorithm is an algorithmic approach to CTO percutaneous coronary intervention, utilizing either an antegrade or retrograde approach, depending on angiographic characteristics and lesion length.11 The details of a hybrid approach are beyond the scope of this article (for more information, visit In this article, we will review some of the basics of the retrograde approach. 

First, perform careful analysis of the angiographic films to look for a suitable collateral channel, preferably septal instead of epicardial. Septal collaterals are safer and usually multiple in number. Therefore, compromise of a single collateral may not result in significant ischemia. In addition, perforation is not usually associated with adverse hemodynamic consequences. Tortuosity may prove to be a limitation to crossing; however, “surfing” of the collaterals (gently advancing the polymer-jacketed wire [Pilot or Fielder] to find the path of least resistance in septal collaterals — not epicardials) may result in successful crossing. Often the angiographically faint or invisible septal may provide the most direct route to the collateralized vessel. Epicardial collaterals tend to be more tortuous and complications can be more catastrophic, especially in patients with an intact pericardium. In patients without prior bypass, these should only be considered if there is not a suitable septal collateral.

Second, dual access is vital, even if significant collaterals are not visualized on diagnostic angiography (especially if done with a single access). Use of a short catheter is important for the retrograde guide. A 90 cm guide will allow for possible externalization of the retrograde wire. Either a 7 or 8 Fr sheath is recommended to allow better passive support, visualization, and “trapping” of gear. Use of one or both radials offers the benefit of reducing bleeding with respect to access, particularly since heparin is used at higher doses than usual. An ACT of > 300 is targeted to reduce the risk of thrombus formation when retrograde equipment is in place. 

Third, retrograde crossing is facilitated with the use of a microcatheter or over-the-wire (OTW) microcatheter, preferably the Corsair catheter (other microcatheters include the Terumo FineCross or the Vascular Solutions SuperCross). The 150 cm Corsair is ideal for the retrograde approach. A workhorse wire is used to deliver the microcatheter to the suitable septal and then changed to a polymer-jacketed wire to navigate the collateral. Once the wire crosses, the Corsair catheter is advanced with counterclockwise rotation. If the catheter does not advance (in the absence of severe angulation or tortousity), then consider changing the catheter to overcome “Corsair fatigue”. 

Once the vessel is crossed, options for recanalization include a true retrograde approach or dissection re-entry. A true retrograde approach involves using a series of wires to penetrate the softer distal end of the CTO and cross the proximal cap in retrograde fashion into the true lumen. If this approach fails, then changing to the dissection re-entry strategy is a second option. To set up the reverse CART technique, a ‘knuckle wire” is used to penetrate into subintimal space. A knuckled wire is essentially a wire with a small J tip to maneuver through the subintimal space, akin to the technique used in peripheral intervention. The wire is manipulated into the antegrade space and the antegrade guide, and can then be trapped in the antegrade guide. The Corsair catheter is advanced into the antegrade guide (if it is an ostial occlusion, the operator may have to snare the retrograde wire and pull it into the antegrade guide). In order to avoid deep seating or potential dissection during this maneuver, close attention must paid to the retrograde guide. Once the Corsair is advanced into the antegrade guide, the wire is externalized and exchanged for a long .014-inch wire. The Viper wire (.014-inch tip) is 335 cm or the 350 cm R350 wire (Vascular Solutions) can be used. The Corsair catheter is then backed into the collateral. The case is completed on the externalized wire. After completion, the Corsair catheter is advanced back into the antegrade guide and the wire removed through the Corsair. The body of the wire should not be removed without the protection of the Corsair, because the externalized wire can exert shear stress and transect the collaterals. Once the retrograde wire is removed through the catheter, the catheter is removed with alternating clockwise/counterclockwise rotation until it reaches the retrograde catheter. This maneuver may result in deep seating of the guides, so must be carefully performed. 

The retrograde approach can be performed with a reasonable degree of safety by experienced operators. There are many subtleties that need to be recognized; it is important to note that we have by no means provided a comprehensive description of this approach. An article cannot replace proctorship, course attendance, in-lab work and live exchanges. More information can be found at or by contacting your Boston Scientific representative about proctorship.

Disclosure: Orlando Marrero reports he is a clinical consultant for interventional cardiology for Boston Scientific. 

Dr. Zaheed Tai reports the following: Terumo (proctor for transradial course), Spectranetics (proctor for laser course, speaker, advisory board), Medicines Company (speakers bureau).

Orlando Marrero can be contacted at:

Dr. Zaheed Tai can be contacted at:


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