Cath Lab Digest

Richard R. Heuser, MD, FACC, FACP, FESC, FSCAI and Punnaiah C. Marella, MD


Abstract
Percutaneous coronary intervention (PCI) of chronic total occlusions (CTOs) remains a challenge for the interventional cardiologist. Recently, techniques including specific wires helpful in treating CTOs, as well as support catheter techniques, have been introduced to improve success rates. We report one such case where successful recanalization of a CTO of the right coronary artery was achieved with a new device.

Chronic total occlusions (CTOs) are considered as one of the most complicated cases for intervention. Many catheters and devices and different techniques have been introduced in recent years to facilitate CTO interventions. The CrossBoss™ catheter (BridgePoint, Minneapolis, Minnesota) is a recent addition to the available devices for treating CTOs. We describe a case in which the combined use of the CrossBoss and a stiff wire helped in the successful intervention of a total right coronary artery (RCA) occlusion.

Case Study and Procedure Report
A 66-year-old gentleman presented in April of 2009 for treatment of a RCA lesion. He first presented 9 months earlier with an acute anterior myocardial infarction (MI). At the time of his original MI, his RCA was found to be 100% occluded, and he had significant stenosis of his circumflex coronary artery. He underwent suction removal of thrombus and placement of drug-eluting stents in his left anterior descending (LAD) artery. The patient was brought back 2 months later for treatment of stenosis in the circumflex artery. Seven months after the original presentation and after an implantable cardioverter-defibrillator and synchronized pacemaker were placed because of an ejection fraction < 35%, he presented with continued chest pain.

In order to facilitate the anticipated placement of the CrossBoss catheter, it is necessary to use a 7–8 Fr guiding catheter system in order to facilitate angiographic testing. Therefore, an 8 Fr sheath was placed via the right groin, and a 5 Fr sheath was placed via the left femoral artery. The diagnostic left Judkins was placed in the LAD to access collateral filling of the RCA. Four-thousand units of heparin were administered and we attempted with 10 minutes of fluoroscopic time to cross the lesion with the Miracle 3TM wire (Asahi Intecc, Aichi, Japan). As part of the FAST-CTO trial (Facilitated Antegrade Steering Technique in Chronic Total Occlusions), this was necessary before we could use the CrossBoss catheter. With placement of the CrossBoss catheter and a Miracle 6™ (Asahi Intecc), we were able to cross half-way through the total occlusion (Figures 1–5). Eventually, we switched to a 1.5 x 10 mm Sprinter® balloon (Medtronic, Inc., Minneapolis, Minnesota) and subsequently a 2.0 x 2 cm long balloon. We inflated the balloon at the site of the CTO, and after traversing the entire CTO, placed a 30 x 3 mm Endeavor™ stent (Medtronic, Inc.) in the mid-portion of the RCA. We then placed a 3.0 x 18 mm Endeavor stent proximally, and a 2.5 x 3 cm long Endeavor stent distally. The stenosis was fully recanalized, and we treated him with intracoronary nitroglycerin. The fluoroscopy time was 57.2 minutes, and 375 cc of contrast were used. The patient went home the following day free of symptoms.

Discussion
CTOs are regarded as one of the most challenging lesions that interventional cardiologists face,¹ and recanalization of these constitutes only a small percentage of overall percutaneous interventions.²

Despite a multitude of novel devices recently designed for these interventions, none of them have been completely studied so far. The CrossBoss is an investigational catheter used specifically for PCI of CTOs. The proximal torque device has a bidirectional rotation with the fast-spin technique, which helps in advancements as the spin reduces the push required. The round 3.0F tip is atraumatic and passes easily through the CTO. In fact, on the table, it appears that the CrossBoss is quite stiff compared to other support catheters such as the Transit and the FineCross. Its round tip, however, reminds one of the Magnum wire used in the past for CTOs. Like the Magnum wire and unlike more flexible hydrophilic catheters, the CrossBoss tends to go into the true lumen rather than be deflected into the path of least resistance. Like the Magnum wire, it also can be advanced without a second wire inside of it. Specifically, with the bidirectional rotation, it actually finds the track of the true lumen. The advantage of the CrossBoss is that unlike the Magnum wire, you can pass a .014 wire of your choice into the CTO effectively (Figure 7). It can cross directly through the CTO or can be advanced through a subintimal path to bypass the CTO.

The CrossBoss worked well crossing the CTO in this patient. We used a Sprinter balloon for successful angioplasty and stent placement. Use of the CrossBoss and the support balloon in this type of complicated intervention has also been reported. This case proves that operator technique and a broad knowledge of different guiding catheters and balloons can prove invaluable when treating these complicated lesions. Our patient was discharged home the day after his procedure. His ejection fraction, which was 18% on initial presentation, improved to 40% at 9 months, and he was clinically symptom-free. This case demonstrates that these complicated lesions, when successfully treated at experienced centers, may improve ejection fraction and angina symptoms.

References
1. Stone GW, Kandzari DE, Mehran R, et al. Percutaneous recanalization of chronically occluded coronary arteries: A consensus document: Part 1. Circulation 2005;112:2364–2372.
2. Stone GW, Reifart NJ, Moussa I, et al. Percutaneous recanalization of chronically occluded coronary arteries: A consensus document: Part 2. Circulation 2005;112:2530–2537.