Antegrade Balloon Transit of Retrograde Wire to Bail Out Dissected Left Main during Retrograde Chronic Total Occlusion Intervention — A Variant of the Reverse CART Technique
_______________________________________________ ABSTRACT: Left main dissection is usually caused by catheter manipulation during diagnostic angiography and occasionally during angioplasty. It is a dangerous complication due to the potential risk of left main territory ischemia. We report a novel iatrogenic cause of left main dissection from a retrograde wire during ostial left anterior descending artery chronic total occlusion retrograde angioplasty. We also report the use of the antegrade balloon as a transit chamber for the retrograde wire after a successful reverse CART technique in order to prevent further left main dissection. This technique is applicable to other retrograde approaches for chronic total occlusion cases where proximal artery dissection is undesirable.
J INVASIVE CARDIOL 2009;21:e113–e118 True ostial left anterior descending artery (LAD) chronic total occlusion (CTO) lesions are especially suitable for a retrograde approach intervention through septal collateral channels from the right coronary artery (RCA). After accessing through the donor RCA and the septal collateral channels, the ostial LAD lesion can be approached with simple retrograde wire crossing, kissing wire, controlled antegrade and retrograde subintimal tracking (CART) technique or the reverse-controlled antegrade and retrograde subintimal tracking (reverse CART) technique. The CART technique involves creating a small subintimal space in the distal part of the CTO using a small balloon over the retrograde wire. The antegrade wire is then passed into the subintimal space after deflation of the retrograde balloon, which allows easy passage of the antegrade wire into the distal true lumen.1 The reverse CART technique is a similar process in reverse. A small subintimal space is created with a small balloon over the antegrade wire and the retrograde wire is manipulated into the subintimal space with the antegrade balloon deflated. This then allows the retrograde wire to pass easily into the proximal true lumen. However, as with all true ostial lesions, there is a danger of retrograde dissection into the left main artery, potentially leading to circumflex territory ischemia and the consequences of acute two-territory ischemia. This danger is particularly high with the reverse CART technique, as the antegrade balloon inflation and the retrograde wire passing can both cause left main dissection. We report a case of left main dissection caused by a retrograde wire during a reverse CART technique and a subsequent bailout technique using the antegrade balloon as a transit compartment for the retrograde wire to prevent further left main dissection. Case Report. An 82-year-old male with non-ST-segment elevation myocardial infarction and acute pulmonary edema underwent coronary angiography after stabilization in intensive care. The 80% culprit lesion in the ostial posterior left ventricular branch of the RCA was treated with a 3 x 12 mm bare-metal stent (Driver, Medtronic, Inc., Minneapolis, Minnesota) covering the distal RCA into the PLV. His circumflex artery was non-dominant and without significant stenoses. His left main artery had an insignificant distal lesion, but his ostial LAD was totally occluded (chronic). Antegrade attempts to open the LAD CTO were unsuccessful with the 6 g miracle wire (Asahi Intecc, Japan) going into a false lumen all the way down to the distal LAD both on the septal and the diagonal side of the vessel. The attempt was abandoned due to extensive dissection in the mid-to-distal LAD. The patient made an uneventful recovery from this episode and was readmitted electively for a retrograde approach via the septal collateral channels to the LAD CTO 3 months later. After 7,000 units of intravenous heparin, a 90 cm 7 Fr AL 1 guide (Medtronic) and a 100 cm 7 Fr EBU 3.5 guide (Vista Brite Tip; Cordis Corp., Miami Lakes, Florida) were placed in the right and left coronary ostia, respectively via bilateral femoral sheaths. Bilateral injections were made to document the LAD CTO in multiple views (Figure 1A). A Rinalto Prowater wire (Asahi Intecc) in an Ichiban microcatheter (Kaneka, Kanagawa, Japan) was passed to the distal posterior descending artery through the stent struts of the previous PLV stent. A Fielder FC (Asahi Intecc) wire was exchanged and managed to cross easily through the septal collateral channel to the LAD without microcatheter support in the septal channel (Figure 1B). Septal channel dilatation was difficult, and a 1.25 x 15 mm balloon (Ryujin, Terumo, Tokyo, Japan) made slow but steady progress through the septal channel with gradual forward-pushing interrupted alternatively by sequential dilatation at 3 atm. After septal channel dilatation, a 2.0 mm x 15 mm over-the-wire balloon (Maverick, Boston Scientific Corp., Natick, Massachusetts) was pushed through the septal channel into the LAD. With the balloon inflated at 8 atm, the fielder FC wire was exchanged out for a Miracle 3 g wire (Asahi Intecc) which was used to attempt to cross the CTO in a retrograde fashion. However, the retrograde wire kept entering the septal side of the LAD (Figure 1C) and occasionally into a higher septal branch. In view of the retrograde wire persistently going into the septal side, an antegrade CTO wire (Conquest Pro 9 g/Confianza 9 g, Asahi Intecc) supported by a microcatheter (Ichiban, Kaneka) was used to penetrate the proximal CTO. After penetration, the CART technique1 was used (Figure 2A), but the antegrade wire was unable to pass into the distal LAD. With the antegrade wire deep inside the proximal CTO, we were able to use a reverse kissing-wire technique to place the retrograde wire in the LAD past the septal branches. Pushing the retrograde balloon forward, we exchanged the antegrade wire with the Rinalto wire (Asahi Intecc) and placed the Conquest Pro 9 g wire (Asahi Intecc) into the retrograde side. The retrograde 9 g conquest Pro wire (Asahi Intecc), supported by the inflated 2.0 x 15 mm balloon (Maverick, Boston Scientific), was able to traverse the CTO in a retrograde fashion and appeared to go into the left main artery (Figure 2B). However, on alternative views, it became clear that the retrograde wire was in fact still subintimal and created a dissection of the left main artery with contrast staining on antegrade injection (Figures 2C and D). At this stage, we became concerned with the possibility of serious left main dissection and decided to proceed to reverse the CART technique. We pushed a 2.5 mm balloon (Apex, Boston Scientific) on the antegrade wire into the proximal part of the CTO inflating it to 8 atm, and used the retrograde Conquest Pro 9 g wire to penetrate the balloon. After confirming that the retrograde wire is in the antegrade balloon by multiple orthogonal views (Figure 3A), we decided to use the antegrade balloon as a transit chamber for the retrograde wire to reduce the chance of further left main dissection. By fixing the retrograde balloon between the ring and little finger of the right hand and pushing the retrograde wire forward into the balloon with the thumb and index finger of the right hand, the operator was able to push the retrograde wire forward with one hand. At the same time, the operator used his left hand to pull the deflated antegrade balloon and wire together back into the antegrade guide in a synchronized fashion with his right hand so that the retrograde wire remained inside the antegrade balloon, and the whole system moved en block into the antegrade guide. Unfortunately, the connection between the antegrade balloon and the retrograde wire was lost at the abrupt angle between the guiding catheter and the left main and retrograde wire prolapsed into the aorta (Figure 3B). The antegrade guide was easily wired by the retrograde wire (Figure 3C), and using the 2.5 mm balloon, we anchored the retrograde wire2 inside the antegrade guide and pushed the retrograde 2.0 mm balloon into the left main artery. The 2.0 mm balloon was used to dilate the lesion from the left main artery back to the mid-LAD and a Rinalto wire (Asahi Intecc) was used to wire the lesion through the antegrade guide (Figure 3D). Four bare-metal stents were placed (Liberté 3 x 28, 2.75 x 28, 2.5 x 16 and 2.25 x 8 mm, Boston Scientific) from the mid-left main to the distal LAD, with excellent angiographic results (Figures 4A and B). Discussion. Iatrogenic left main dissection is most commonly caused by catheter manipulation either during diagnostic angiography, angioplasty or from balloon rupture during angioplasty.3–6 It is a dangerous complication due to the potential possibility of left main territory ischemia leading to refractory heart failure and cardiogenic shock. Angioplasty of ostial LAD or circumflex CTO lesions rarely cause left main dissection if performed in the antegrade fashion. However, the risk of left main dissection is increased when retrograde methods are used. The treatment of CTOs in this era can be broadly divided into antegrade approaches and retrograde approaches. For ostial LAD CTOs, the particular difficulties in the antegrade approach include wire slippage into the circumflex artery and the numerous septal and diagonal branches, which often lead to misdirection of the antegrade wire. Of course, these difficulties can be partially overcome with intravascular ultrasound-guided ostial CTO puncture and the parallel-wire technique. In our case, the previous antegrade attempt with a parallel wire had created massive dissection in the mid-LAD beyond the CTO. The retrograde approach can be performed through collateral channels. Most commonly used are the septal collateral channels, although reports of using grafts, epicardial collateral, apical collateral, right-to-circumflex, diagonal-to-diagonal and other collaterals are cited in the literature. Once the retrograde wire has passed the collateral and a suitable support system is established, either with microcatheter, over the wire balloon, or a septal channel dilator, the retrograde wire can begin to cross the CTO. There are a wide range of techniques used to cross a CTO using the retrograde approach: (i) The retrograde wire can be used as a simple marker wire; (ii) the retrograde wire can simply pass through the CTO into the proximal true lumen; (iii) the retrograde wire can pass through the lumen aiming at a proximal antegrade marker wire; (iv) the antegrade wire can be placed into the lesion and the retrograde wire used to aim at the antegrade wire in a kissing-wire technique; and finally, (v) the kissing-wire technique can also be done with the antegrade wire attempting to kiss the retrograde wire buried in the distal part of the CTO. In addition, either the antegrade or retrograde wires can be curved into a knuckle wire and pushed into the CTO, creating a subintimal dissection, and the other wire can then be used to access this knuckle-wire subintimal space. Beyond the use of wires, the CART technique can be used by making a small subintimal space in the distal part of the CTO using the retrograde balloon and then accessing this space with the antegrade wire. Similarly, the antegrade balloon can be used to make a small subintimal space in the proximal part of the CTO, and the retrograde wire can be used to access this space in what is known as the reverse CART technique. Alternatively, both the antegrade and retrograde wires can be passed deep into the CTO and both antegrade and retrograde balloons passed into the CTO until there is an overlapping segment with both balloons. Simultaneous low-pressure inflation of these balloons would enlarge both the antegrade and retrograde subintimal space, leading to confluence of the subintimal space, allowing easy passage of either antegrade or retrograde wires. Usually, the CART technique is preferable to the reverse CART technique in the ostial LAD position because the antegrade wire is more easily manipulated and has less risk of causing exit dissection. Also, the antegrade balloon inflation can potentially cause left-main dissection. We chose the retrograde approach in this case because of the previous failed antegrade approach. The classic CART technique of attempting to pass the antegrade wire into a subintimal space created by the retrograde balloon was used initially. However, due to the severe mid-LAD dissection from the previous antegrade attempt, the antegrade wire was caught up in the dissection folds after crossing the CTO and could not be smoothly transitioned into the distal LAD. Therefore, with reluctance, we attempted to pass the retrograde wire directly into the proximal true lumen. This was complicated with the retrograde wire, causing left main dissection, and we were unable to pass the retrograde wire into the true lumen. Concerned with the possible dangers of left main dissection, we chose to progress to reverse CART. However, we made a slight alteration to the traditional technique of the reverse CART. Instead of deflating the balloon and using the retrograde wire to wire the subintimal space, we kept the balloon inflated at 8 atm. We used the retrograde wire to puncture the inflated antegrade balloon, thus ensuring that the wire is inside the balloon chamber. The aim of this approach is to keep the wire tip inside the balloon until the retrograde wire is safely beyond the dissected portion of the left main artery, thus in a sense using the antegrade balloon as a transit chamber to protect the left main from the sharp retrograde wire tip. After successfully puncturing the antegrade balloon and confirming intra-balloon position of the retrograde wire in multiple orthogonal views, we deflated the balloon and pulled back the balloon simultaneously while advancing the retrograde wire. Under fluoroscopy, we slowly moved the balloon backward and the retrograde wire forward in a synchronous fashion, ensuring that the retrograde wire stayed in the antegrade balloon chamber, thereby preventing further dissection of the left main artery. Thus, our technique differs from the reverse CART technique in two main ways. First, the antegrade balloon remains inflated during retrograde wire passing, and then, after balloon deflation, the retrograde wire is moved forward in synchrony with the antegrade balloon backward movement to ensure that the retrograde wire tip stays inside the balloon. This guarantees the safety of the proximal vessel from retrograde wire injury. The advantages of this technique are two-fold. First, in the traditional reverse CART technique, it is sometimes unsuccessful because the retrograde wire cannot puncture the proximal subintimal space. The reason for failure to puncture is partly due to inadequate pressure in the subintimal space for the retrograde wire to push against puncturing into the subintimal space. Also, subintimal space collapse after balloon deflation reduces the size of the target, leading to retrograde wire miss. With the balloon inflated, the target size is maintained and even enlarged, and the pressure inside the subintimal space is increased, allowing the retrograde wire to push against it and to puncture it. Of course, the wire must now puncture the balloon wall, but with the Conquest series, we have not found this to be a problem.7 The second advantage is the ability to protect the proximal vessel from retrograde wire-tip damage by using the balloon as a transit chamber for the retrograde wire. Conclusion. We report a novel iatrogenic complication of retrograde PCI, that of left-main dissection by a retrograde wire. We also describe a method to prevent further dissection by using an antegrade balloon as a transit chamber for the retrograde wire through the dissected left main artery. This technique may be useful in a broader set of patients to prevent proximal vessel dissection after a successful reverse CART technique. _______________________ From the Division of Cardiology, Department of Medicine and Therapeutics, Prince of Wales Hospital, Chinese University Hong Kong. The authors report no conflicts of interest regarding the content herein. Manuscript submitted December 12, 2008, provisional acceptance given March 3, 2009, and final verslon accepted March 8, 2009. Address for correspondence: Eugene Brian Wu, MD, Division of Cardiology, Department of Medicine and Therapeutics, Prince of Wales Hospital, Chinese University Hong Kong, Ngan Shing Street, Shatin, Hong Kong. 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