CTO PCI: Complexity Begets Complexity

We elected to attempt CTO PCI with dual arterial access using right common femoral as well as right radial access. Access in both vessels was obtained without difficulty using ultrasound guidance and a micropuncture needle. An 8 French 90 cm Amplatz left (AL)1 guide catheter that fit well and provided good support was inserted through the 8 French femoral sheath. We then attempted to deliver a 7 French Extra Backup (EBU) 3.75 guide (Medtronic) to engage the left main. After delivering the guide catheter in the ascending aorta, severe radial spasm occurred (Figure 1A), precluding any movement of the catheter. Warm blankets were placed around the arm and nitroglycerin was injected subcutaneously around the right radial artery without success. Sublingual nitroglycerin and heavy sedation were also administered without success. Left common femoral access was obtained and a Judkins right (JR)4 guide catheter was advanced to the origin of the right radial artery (Figure 1A), through which intra-arterial nitroglycerin, verapamil, nicardipine, and Rotaglide (Boston Scientific) were administered. Despite all these attempts, the catheter could not be removed. Anesthesia administered propofol that also could not relieve the spasm. General anesthesia and assistance from vascular surgery was planned. A blood pressure cuff was placed in the right arm and inflated above the arterial pressure for 5 minutes, following which the EBU guide catheter was finally able to be retrieved. 

After removing the radial catheter, the left main was engaged with the same 7 French EBU 3.75 guide catheter, advanced through the left common femoral artery. Dual injection demonstrated a complex RCA CTO (Figure 1B-C) with a clear proximal cap, long length (approximately 60-70 mm), and severe calcification with the distal vessel filling via septal and epicardial collaterals from the left coronary artery. There was a bifurcation at the distal cap as well as multiple bridging collaterals between the posterior descending artery (PDA), the right posterolateral (PLV), and acute marginal branches. 

Antegrade wire escalation was initially performed using a Corsair Pro microcatheter (Asahi Intecc) and a Samurai RC guidewire (Boston Scientific), followed by a Pilot 200 (Abbott Vascular) and a Gaia second (Asahi Intecc) guidewire that advanced towards the distal right coronary artery; however, subsequently, guidewires kept entering a large acute marginal branch (Figure 1D). Multiple attempts were made to redirect the guidewire into the distal right coronary artery without success; hence, we elected to attempt retrograde crossing. 

A 150 cm long Corsair Pro microcatheter was inserted, with difficulty, into a large first septal branch. We performed surfing using a Sion and a Fielder FC guidewire (Asahi Intecc) without success. Surfing is a technique for septal collateral crossing in which a guidewire is advanced rapidly with simultaneous rotation until it either buckles or advances into the distal target vessel without contrast visualization.¹ Selective injection through the microcatheter demonstrated some connections with what appeared to be the PDA. After multiple attempts, a Sion guidewire was advanced through the collateral; however, the wire entered an acute marginal branch and not the PDA or the large right posterolateral branch (Figure 1E). As a result, we removed the septal guidewire and decided to attempt retrograde crossing via an epicardial collateral from the circumflex. 

There was significant difficulty advancing a guidewire into the distal circumflex due to previously placed stents in the obtuse marginal, but our efforts were eventually successful. Unfortunately, the Corsair would not cross, likely because of interference with the stent strut. Predilation was attempted with a 1.5 balloon, but we were still unable to cross into the circumflex. A second guidewire was used to wire into the distal circumflex, permitting advancement of a Caravel microcatheter (Asahi Intecc) into the distal circumflex. Multiple attempts were made to advance a guidewire into the epicardial collateral that was originating at a 90° angle from the distal circumflex without success. The Caravel was removed and a SuperCross 120 microcatheter (Vascular Solutions) (Figure 1F) was inserted, through which a Suoh 03 guidewire (Asahi Intecc) was able to advance into the right posterolateral branch. The Caravel was advanced over the Suoh 03 guidewire; however, a guidewire retrograde was unable to advance into the distal right coronary artery, despite multiple attempts with various guidewires and multiple selective injections. After multiple attempts, we decided to leave the guidewire into the right posterolateral branch as a marker wire and reattempt antegrade crossing (Figure 1G). 

The same challenge was encountered with the antegrade guidewires entering the right acute marginal branch. After multiple attempts, a Hornet 14 guidewire (Boston Scientific) was successfully advanced into the distal RCA, followed by the Corsair Pro microcatheter. The Hornet 14 was exchanged for a Pilot 200 guidewire that advanced towards the distal RCA as confirmed by contralateral injection demonstrating concordant movement of the distal RCA. The Corsair Pro was advanced further distally and then a Fielder XT guidewire was knuckled all the way to a distal branch of the right posterolateral vessel (Figure 1H). We could not, however, advance the knuckle into the large right posterolateral into which the retrograde guidewire had been placed. To achieve wiring of the posterolateral branch, we initially tried a dual lumen microcatheter (Twin-Pass Torque [Vascular Solutions]) without success (Figure 2A). A knuckled Pilot 200 guidewire was finally able to advance subintimally into the right posterolateral branch (Figure 2B). Another attempt was made to advance the retrograde guidewire into the now wired distal RCA, again without success. A Stingray balloon was delivered over the antegrade guidewire into the right posterolateral branch, using the retrograde guidewire as marker of the distal true lumen. Using the double-blind stick-and-swap technique with a Gaia Second and a Pilot 200 guidewire, we successfully re-entered into the distal true lumen (Figure 2C). 

The RCA was predilated. After removing the retrograde guidewire and microcatheter, and confirming that there was no injury or perforation of the collateral, a 2.5 mm x 38 mm drug-eluting stent was delivered into the right posterolateral branch (Figure 2D) and then overlapped more proximally with 3 additional stents: a 2.5 mm x 38 mm and two 3.0 mm x 38 mm stents (Figure 2E). The stents were postdilated with a 3.0 mm NC balloon (Medtronic) up to 20 atmospheres (Figure 2F), providing an excellent final angiographic result with TIMI-III flow, in both the right posterolateral and the acute marginal branch (Figure 2E). Intravascular ultrasound (IVUS) demonstrated good stent expansion. 

The patient tolerated the procedure well and had resolution of his symptoms at hospital discharge. Fluoroscopy time was 119 minutes and air kerma radiation dose was 3.443 Gray.  The DyeVert Plus contrast reduction system (Osprey Medical) was used in the left main guide catheter: total contrast volume used was 385 ml with 239.6 ml saved (43.1%) (Figure 2H). Pre-procedural creatinine was 1.06 mg/dL and post-procedural creatinine (48 hours) was 0.84 mg/dL.

Discussion

Our case illustrates several challenges that were encountered during PCI of a complex RCA CTO and how these challenges were successfully overcome using a variety of techniques. 

Radial Artery Spasm

Radial access is increasingly being used for CTO procedures and complex PCI, given its lower risk for access complications and bleeding. The severe radial artery spasm that developed in our patient after guide advancement to the ascending aorta led to guide catheter entrapment. Radial artery spasm is the most common complication of the radial access in PCI, occurring in approximately 10.3% of patients, most commonly in women.² Radial artery spasm can lead to significant difficulties in accessing the vessel and delivering equipment, and guide catheter entrapment, as in our case. Various techniques were used to overcome this complication. First, calcium channel blockers and nitrates were injected through the radial sheath, and nitroglycerine was injected in the subcutaneous tissue around the radial artery. Second, a warm blanket was applied around the affected arm. Third, vasodilators and lubricants (Rotaglide) were administered inside the vessel after advancing another catheter to the proximal radial artery. Fourth, deep sedation with propofol was given. Fifth, a blood pressure cuff was inflated above systolic pressure in the affected arm while we prepared for induction of general anesthesia. Blood pressure cuff inflation eventually led to ischemia-induced vasodilation, allowing for guide catheter removal. 

CTO PCI: The Importance of Change

Our case illustrates the importance of early change during CTO PCI if the initially selected strategy does not work, as advocated by the hybrid algorithm.³ This requires expertise in all CTO PCI techniques (antegrade wiring, antegrade dissection and re-entry, and the retrograde approach). In our procedure, after failed antegrade wire escalation attempts, we changed to the retrograde approach. Going through septal collaterals failed; hence, we changed to an epicardial collateral. After this failed, we used antegrade dissection/re-entry with the retrograde guidewire acting as a marker of the distal true lumen position, until successful crossing was achieved (Figure 3). 

Overcoming Tortuosity

There was significant difficulty in accessing the epicardial collateral that was originating at a 90° bend from the distal circumflex, but we were successful using the SuperCross 120 microcatheter, which has a 120° angle at the distal tip. The SuperCross microcatheter is a single lumen, over-the-wire microcatheter that has a low profile and either a straight or an angled tip (45°, 90°, and 120°). The catheter’s distal tip angulation allows for direction of the guidewire through tortuosity. Alternative approaches include use of the Venture catheter (currently not available), the reversed guidewire technique, and the distal blocking balloon technique.⁴

Limiting Contrast Volume 

With the newer x-ray systems and meticulous attention to radiation safety, even complex procedures such as CTO PCI can be achieved with low radiation dose. As a result, contrast volume often becomes the limiting factor in such procedures, decreasing the likelihood of success and increasing the likelihood of complications. Pre-procedural hydration, use of iso-osmolar contrast media, and limiting contrast volume can minimize the risk for contrast-induced nephropathy.⁵ In our case, we also used the DyeVert system (Osprey Medical), which is designed to minimize contrast backflow into the aorta, limiting the volume of contrast administered by approximately 40%.⁶ Moreover, the DyeVert system allows contrast monitoring in real time and alerts physicians when pre-specified contrast volume limits (based on pre-procedural eGFR) have been reached. 

Conclusions

CTO PCI can be challenging at each and every step, including obtaining access, crossing the occlusion, delivering equipment, and ensuring optimal stent deployment. Thoughtful planning, tenacity, creativity, and awareness of potential techniques and tools to overcome challenges and complications are key to a successful final outcome.

References

1. Brilakis E. Chapter 6 - The Retrograde Approach. In: Manual of Chronic Total Occlusion Interventions (Second Edition). Academic Press; 2018:197-251.
2. Gorgulu S, Norgaz T, Karaahmet T, Dagdelen S. Incidence and predictors of radial artery spasm at the beginning of a transradial coronary procedure. J Interv Cardiol. 2013; 26(2): 208-213.
3. Brilakis ES, Grantham JA, Rinfret S, et al. A percutaneous treatment algorithm for crossing coronary chronic total occlusions. JACC Cardiovasc Interv. 2012 Apr; 5(4): 367-379.
4. Brilakis E. Chapter 2 - Equipment. In: Manual of Chronic Total Occlusion Interventions (Second Edition). Academic Press; 2018: 21-99.
5. Ebisawa S, Kurita T, Tanaka N, et al. Impact of minimum contrast media volumes during elective percutaneous coronary intervention for prevention of contrast-induced nephropathy in patients with stable coronary artery disease. Cardiovasc Interv Ther. 2016; 31(1): 13-20.
6. Sapontis J, Barron G, Seneviratne S, et al. A first in human evaluation of a novel contrast media saving device. Catheter Cardiovasc Interv. 2017; 90(6): 928-934.

¹Minneapolis Heart Institute, Abbott Northwestern Hospital, Minneapolis, Minnesota, USA; ²Faculty of Medicine of Tunis, University of Tunis El Manar, Tunisia; ³Division of Invasive Cardiology, Second Department of Internal Medicine and Cardiology Center, University of Szeged, Hungary.

The authors can be contacted via Emmanouil S. Brilakis, MD, PhD, atesbrilakis@gmail.com. 

Disclosures: Dr. Hatem Najar, Dr. Peter Tajti, and Dr. Iosif Xenogiannis report no conflicts of interest regarding the content herein. Dr. Emmaouil Brilakis reports consulting/speaker honoraria from Abbott Vascular, ACIST, Amgen, Asahi, CSI, Elsevier, GE Healthcare, Medicure, and Nitiloop; research support from Boston Scientific and Osprey; board of directors: Cardiovascular Innovations Foundation; board of trustees: Society of Cardiovascular Angiography and Interventions.

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Commentary: "If At First You Don’t Succeed… A Tour-de-Force in Complex CTO Intervention" by Tim A. Fischell, MD, FACC, FSCAI