Transvenous IVUS-Guided Percutaneous Coronary Intervention for Chronic Total Occlusion: A Novel Strategy

ABSTRACT: The major obstacle to successful recanalization of a chronic total occlusion (CTO) is difficulty in passing the guidewire through the occlusion. We report successful transvenous intravascular ultrasound (IVUS)-guided percutaneous coronary intervention for CTO of the coronary artery in two patients, one with CTO of the left circumflex artery and the other with CTO of the left anterior descending artery. The procedure involved the passage of a guidewire through the CTO lesion under fluoroscopic guidance and insertion of an IVUS catheter into the cardiac vein parallel to the target artery. Angiography after 8 months revealed no restenosis in either patient.

J INVASIVE CARDIOL 2013;25(7):E143-E146

Key words: chronic total occlusion, IVUS

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The treatment of chronic total occlusion (CTO) remains one of the major challenges of interventional cardiology, although a recent meta-analysis suggested that successful recanalization was associated with decreased mortality and morbidity.^1,2 The major obstacle to successful recanalization of a CTO lesion is difficulty in passing the guidewire through the occlusion. To overcome this problem, we investigated the potential benefits of transvenous intravascular ultrasound (IVUS)-guided percutaneous coronary intervention (PCI) in 2 patients — 1 patient with CTO of the left circumflex (LCX) artery and 1 patient with CTO of the left anterior descending (LAD) artery (Figure 1). The procedure involved the passage of a guidewire through the CTO lesion under fluoroscopic guidance and insertion of an IVUS catheter into the cardiac vein parallel to the target artery. The IVUS catheter provided accurate images, and we successfully crossed the true lumen of the lesions and dilated the occluded sites in both patients. This is the first report, as per our knowledge, of successful treatment of a CTO lesion using transvenous IVUS-guided PCI.

Case Report 1. A 58-year-old man presented with acute myocardial infarction and underwent PCI for an infarct-related segment in the mid-LAD. Seven days later, transvenous IVUS-guided PCI for CTO of the mid-LCX  was performed (Figure 2A). A 6 Fr Heartrail II AL 1.0 guiding catheter (Terumo Corporation) was engaged into the coronary sinus and a Visions PV 0.018 IVUS catheter (Volcano Corporation) was inserted into the cardiac vein parallel to the LCX following insertion of an Asahi Grand Slam guidewire (Asahi Intec). An Equation 0.008 guidewire (Cordis Corporation) and a Miracle 6 g guidewire (Asahi Intec) both failed to pass through the lesion because of severe calcification. However, a Conquest Pro guidewire (Asahi Intec) crossed the true lumen during IVUS and fluoroscopy (Figures 2C and 2D). Therefore, we used a traditional single-guidewire approach during the procedure. Blood flow in the distal LCX improved substantially after balloon angioplasty (Figure 2B). Follow-up angiography performed 8 months later revealed the absence of restenosis at the PCI site. 

Case Report 2. An 85-year-old man presented with acute myocardial infarction and underwent PCI for an  infarct-related segment in the proximal right coronary artery. Eight days later, transvenous IVUS-guided PCI for CTO of the mid-LAD (Figure 3A) was performed. A 6 Fr Hertrail II AL 1.0 guiding catheter was engaged in the coronary sinus and an Eagle Eye Platinum IVUS catheter (Volcano Corporation) was inserted into the great cardiac vein following insertion of a Grand Slam guidewire. The IVUS catheter enabled us to visualize accurate images for the position of an Equation 0.008 guidewire in the coronary artery. We attempted to bypass the lesion using a single guidewire by concurrently viewing the IVUS and fluoroscopic images (Figures 3C-3H). A distal-occluded IVUS image (Figure 3F) showed that the guidewire was adjacent to the vessel. Because of the probability of the guidewire being in the subintimal space, we did not advance it further; instead, we retracted it to the previous correct position and advanced it further until it successfully traversed the CTO lesion (Figures 3G-3H). The occluded site was dilated by a PCI balloon with a diameter of 2.5 mm. A 3.0 × 24 mm Nobori stent (Terumo Corporation) and a 2.5 × 28 mm Nobori stent were then deployed at the lesion site. Angiography confirmed the success of the procedure, with no complications observed (Figure 3B). Follow-up angiography performed 8 months later revealed the absence of restenosis at the PCI site.

Discussion. The procedure for PCI of a CTO lesion has seen major advances in recent years, with an improvement in success rates. However, the success rates are still rather low, mainly because of failure of the guidewire to traverse the lesion.^3-5 

We successfully treated 2 patients with CTO of the LAD and LCX, respectively, using transvenous IVUS-guided PCI. It is well known that the cardiac vein runs parallel to the main trunk of the LAD and LCX. We therefore inserted an IVUS catheter into the cardiac vein, which enabled us to view the guidewire in the coronary artery. Single guidewire crossing was performed by concurrently viewing IVUS and fluoroscopic images. 

In both patients, we performed transvenous IVUS-guided PCI because they had no usable collateral channels for a retrograde approach. In the LCX case, a Visions PV 0.018 IVUS catheter was inserted easily into the cardiac vein, and this catheter provided accurate images of the CTO despite the small size of the vessel. In traditional IVUS-guided PCI for CTO of a small vessel, insertion of the IVUS catheter in the subintimal space of the small vessel is unfavorable because it is usually not possible to insert an IVUS catheter into this space. In the LAD case, we used an Eagle Eye Platinum IVUS catheter with a low profile because the distal great cardiac vein was narrow and it was necessary for the IVUS catheter to cross over the bend of the cardiac vein. During the procedure, a homocollateral that had been observed previously disappeared because the collateral flow from the right coronary artery increased after emergency PCI. We performed PCI by viewing the position of the guidewire at the CTO lesion and distal non-occluded site using only IVUS and fluoroscopic images, with no right coronary angiography. In both cases, an optimal result was obtained via the antegrade approach and a single guidewire technique. Futhermore, no complications such as arterial and venous perforation were observed. 

Transvenous IVUS-guided PCI only requires an IVUS catheter and angiography system, both of which are used commonly in cardiovascular interventions. No other special systems are required. Although this special procedure requires insertion of an IVUS catheter into the cardiac vein, it is very easy. During treatment for CTO of the coronary artery, it is important that the guidewire is in the vessel and not in the subintimal space while it is advanced through the CTO lesion. This leads to safe and successful bypassing of the CTO lesion by the guidewire. In transvenous IVUS-guided PCI, IVUS images show the guidewire as a hyperechoic dot. Visualizing the guidewire in an artery using IVUS aids in confirming that the guidewire is not outside the artery. If the guidewire is seen along the outer edge of the artery, it may indicate a possibility of the guidewire being in the subintimal space. Therefore, during transvenous IVUS-guided PCI, the guidewire should be advanced through the occlusion while continuously monitoring its position in relation to the vessel.

Recently reported IVUS-guided CTO treatments7-9 included methods wherein IVUS images of the true lumen, obtained by inserting the catheter into a side branch or subintimal area, were used. In the former technique, it is only possible to obtain information of entry into the CTO, whereas in the latter technique, an IVUS catheter is inserted into the subintimal space, leading to the possibility of coronary perforation and dissection. In some cases, it is not possible to insert an IVUS catheter into the subintimal space because of severe calcification. When the CTO is parallel to the cardiac vein, transvenous IVUS-guided PCI provides information on the entire length of the CTO, increasing the possibility of a guidewire passing through the intima or true lumen. Transvenous IVUS-guided PCI, however, cannot be used for CTO lesions that are not parallel to the cardiac vein. In addition, accurate images of the artery, including the guidewire, may not be obtained in patients with very severely calcified lesions. Although transvenous IVUS-guided PCI is associated with some complications such as injury of the cardiac vein in addition to other common complications associated with CTO treatment, we did not experience these problems in the 2 cases reported here. Even with these limitations, we consider that transvenous IVUS-guided PCI may increase the treatment success rate for CTO lesions parallel to the cardiac vein, thereby making it a very useful treatment for such lesions.

Conclusion. Transvenous IVUS-guided PCI may be a more feasible strategy for PCI of CTO lesions parallel to the cardiac vein. Further studies on the technique are warranted in a larger number of patients.

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