Retrograde Recanalization of a Chronic Ostial Occlusion of the Left Anterior Descending Artery: (Full title below)

Retrograde Recanalization of a Chronic Ostial Occlusion of the Left Anterior Descending Artery: How to Manage Extreme Takeoff Angles

pg. E7 - E12 ABSTRACT: Chronic total coronary occlusions (CTO) still remain one of the most technically challenging clinical scenearios in which to perform interventions. Although the antegrade approach is the most common method of CTO recanalization, a retrograde attempt improves the success rate and its usage has been increasingly adopted in the recent years. However, the retrograde method requires exceptional expertise and skills in order to apply a wide variety of strategies, devices and imaging modalities. We report a case of retrograde recanalization of an ostial left anterior descending artery CTO of at least 10 years duration, and discuss some specific issues of a new channel dilating catheter, and practical precautions to keep in mind in the retrograde approach such as the availability of snare technique to facilitate retrograde wire capture and externalization. J INVASIVE CARDIOL 2010;22:E7–E12 Key words: Chronic total coronary occlusion / retrograde technique / percutaneous coronary intervention / collaterals Almost one third of patients with significant coronary stenosis visible with angiography have a chronic total occlusion (CTO). The majority of these CTOs are being treated medically or referred to surgery.1,2 Percutaneous coronary intervention (PCI) and successful recanalization of CTOs remain a major challenge for interventional cardiology. Successful CTO treatment when compared to failed PCI to CTO, is associated with reduced angina, significant improvement in global left ventricular ejection fraction and improved survival.3–6 The antegrade technique is the regular approach for a CTO, but even in experienced centers and with advanced equipment, the success rate continues to be not more than 80%. So, the retrograde approach is an alternative in failed cases and improves the results in CTO recanalization.7 This advanced technique is applicable when it is deemed possible to pass a wire to the CTO through the collateral donor artery retrogradely towards the vessel segment distal to the CTO, but requires advanced equipment and operator experience, but also the ingenuity to deal with potential difficulties arising from this complex approach. Here, we describe a successful case of a retrograde approach via a septal branch in the treatment of an ostial left anterior descending artery CTO of at least 10 years duration, facilitated by a new channel dilating catheter, and requiring unusual techniques such as intracoronary wire catching by micro snares. Case report. We present the case of a 73-year-old male patient with a history of hypertension, hyperlipidemia, previous smoking habit (40 cigarettes per day for 20 years), coronary artery disease, and urothelial carcinoma with complete resection. He was treated with ASA, ramipril, metropolol, torsemide, simvastatin, and ezetimibe. He had an acute coronary syndrome in 1999 when he was diagnosed with three vessels coronary disease. The coronary angiography performed in 1999 revealed a CTO of the ostium of the left anterior descending artery (LAD), left circumflex (LCX) artery with severe stenosis in its mid and distal portion and moderate stenosis in the proximal right coronary artery (RCA) (Figure 1A, B, and C). The tight LCX stenosis was treated by balloon angioplasty, whereas the LAD was not treated even though in retrospect the poor collateralization at that time indicated that the LAD occlusion must have been recent. The left ventricular angiogram at that time revealed anterior akinesia consistent with a prior anterior myocardial infarction. In February 2008, the patient was referred to our center because of worsening chest pain on exertion. The electrocardiogram showed no Q-waves in anterior leads, and echocardiography was done revealing severe hypokinesia in the anterior wall but with normal wall thickness, and normal global left ventricular ejection fraction. A magnetic resonance imaging study demonstrated a subendocardial infarction in the septum and middle portion of the anterior wall with less than 25% of transmural late gadolinium enhancement (Figure 2). We repeated the coronary angiography showing the ostial LAD total occlusion; the distal LAD beyond the CTO was supplied by very well developed septal collaterals from the RCA (Figure 1D). A first PCI attempt using the conventional antegrade approach with double injection technique was performed (Figure 3A &B). However, we failed because it was impossible to determine the exact entrance of the LAD. The patient was brought back for a retrograde approach two months later. We were able to pass a wire through a septal connection from the posterior descending artery of the RCA towards the proximal LAD. A Quick-cross microcatheter (Spectranetics Corp., Colorado Springs, Colorado) was advanced and a Whisper LS wire (Abbott Vascular, Santa Clara, California) was directed towards the proximal LAD. With careful manipulation it was possible to advance the wire beyond the proximal occlusion; however, the wire was subintimal at the level of the left main coronary artery (Figure 3C). After some manipulation, it was not possible to redirect the wire due to poor wire tip control. Therefore, the attempt was abandoned, and instead the RCA lesion was treated in an attempt to improve retrograde collateral perfusion. Despite this intervention, symptoms remained similar during exercise, and the decision was to proceed to a third attempt. There were two rationales for an additional attempt with promise to make the retrograde approach successful: first to enter into a more distal septal connection to improve the leverage for the retrograde wire manipulation, and to enhance tip control with a new channel dilator (Corsair catheter, Asahi Intecc. Co. Japan) to be advanced through the collateral connections. Bifemoral access was established, a 7 Fr Launcher AL-1 guiding catheter (Medtronic, Inc. Minneapolis, Minnesota) was used for the RCA engagement and a 4 Fr JL-4 diagnostic catheter (Medtronic) was used to engage the left coronary artery, allowing for better visualization of the LAD occlusion and retrograde wire direction. Multiple selective contrast injections from microcatheter were performed to select the least tortuous septal collateral branch to reach the distal CTO vessel. A Whisper LS guidewire 300 cm length (Abbott Vascular) inside an Asahi Corsair channel dilator were passed into the targeted septal branch. We managed to advance the guidewire and the channel dilator to the mid portion of the LAD (Figure 4). At that point of the procedure, we decided to change the diagnostic catheter in the left coronary artery to an 8 Fr Launcher JL-4 (Medtronic), allowing for better visualization of the LAD ostium and for introduction of intravascular ultrasound (IVUS) control. Then the retrograde guidewire was exchanged for a Miracle 3G (Asahi) to penetrate the distal cup of the occlusion. With IVUS control in the ramus intermedius, we visualized the entrance of the LAD into the left main trifurcation and the correct position of the guidewire within the lumen (Figure 5A). The Miracle crossed the CTO lesion and could be advanced into the LCX (Figure 5B, 5C, 5D). After this we could advance the channel-dilator through the occlusion into the LCX, but it was impossible to negotiate the angle from the LAD into the left main artery. Even after exchange of the Miracle for several softer wires (Whisper LS, Prowater, and Pilot 50), maneuvers to enter the left main or loop back into the left main with these wires failed. As it was not safe to dilate the ostium of the LAD into the left main artery from a retrograde approach without securing the left main stem with a wire, we decided to try to capture the retrograde wire to externalize it into the antegrade guiding catheter. We introduced a 300 cm length whisper LS (Abbott) guidewire through the RCA, and advanced the loop of a Multi-Snare 3F (PFM, Cologne, Germany) into the bifurcation of the left main artery, and were then able to catch the wire tip of the retrograde wire, and pull it all the way out of the antegrade guiding catheter. It was externalized through the sheet (Figure 6). Subsequently, we introduced a Sprinter rapid exchange balloon 2.0 mm x 15 mm (Medtronic) into the floppy tip of the externalized wire and predilated the proximal LAD from an antegrade route. Recovery of antegrade flow was achieved. A microcatheter was then advanced over the externalized wire through the dilated occlusion. An Extra Sport guidewire (Abbott) was then advanced antegradely through this microcatheter while the retrograde wire was gradually removed, maintaining the Corsair catheter as a protective sheet of the septal collaterals until the soft part of the retrograde wire was removed through the collateral channel (Figure 7A, 7B). An IVUS examination was done in the LAD to visualize the lesion extent in the proximal LAD, and to confirm that the guidewire and IVUS catheter were in the true lumen through the entire segment. After protecting the LCX with another floppy wire, the CTO lesion in the proximal LAD was dilated and a Xience V stent 2,75 mm x 28 mm (Abbott) was implanted. Stent post-dilatation was executed by a 3.5 mm x 8 mm Quantum Maverick balloon (Boston Scientific Corp., Natick, Massachusetts), yielding a sufficient angiographic result (Figures 7C and D). We confirmed adequate stent expansion with the IVUS. The patient was discharged free of angina. Discussion. We presented a successful case of a percutaneous treatment for an ostial LAD CTO of at least 10 years duration. However, the procedure was only possible after applying new devices and techniques in a retrograde approach with collateral channel dilation, capturing of the retrograde wire and externalization. Such a complex approach, especially when previous attempts failed, can only be justified when there is a potential benefit for the patient. Before any reopening of a CTO it is important to base the indication for such a complex procedure with presumably higher radiation and contrast exposure, on the presence of symptoms or objective evidence of viability/ischemia in the territory of the occluded artery. In our patient, with severe hypokinesia of the anterior wall, the indication was based on several arguments: 1) the persistent angina despite the revascularization of the non-occluded arteries, and the well-developed collaterals to the LAD territory (during exercise, collaterals do not have enough functional reserve to increase collateral perfusion and they are not able to maintain myocardial blood supply, resulting in myocardial ischemia8–10; 2) the ECG did not show Q waves in the anterior leads, which was previously described as a predictor of recovery of regional wall motion with extremely high sensitivity and specificity11; and 3) the unequivocal evidence of viability of the myocardium measured by magnetic resonance. This technique is considered currently the best and most precise non-invasive imaging approach to evaluate myocardial fibrosis and perfusion.4,12 Considering the coronary anatomy, in this type of flush ostial occlusions, the antegrade approach is unlikely to succeed, however, in some instances the proximal cap of the occlusion may be rather soft, and a penetration possible. Indeed in this case the antegrade wire was advanced relatively far, but obviously in a subintimal space. From hindsight, the extreme takeoff angle of the LAD had made any antegrade attempt impossible. When the antegrade approach failed, the retrograde attempt provides an alternative. However, even with well developed transseptal collateral connections, the retrograde approach will only be successful with dedicated tools and use of a large variety of procedural options, which are not part of the regular interventional arsenal for complex nonocclusive lesions. Also this technique is challenging regarding the guidewire manipulations once passed through the collaterals, and it is associated with marked exposure of patients and operators to radiation and potential complications (e.g., damage of the collateral-donor artery, periprocedural MI).13 We would like to emphasize some important points of the procedural technique, which clearly influence the success. First, it is crucial to select the right collateral channel to reach the distal edge of the occluded artery. In our first retrograde approach we selected a too proximal collateral which did not allow us to have sufficient control of the wire tip. To assess the pathway, supra-selective injection with the microcatether to choose the most promising collaterals should be performed. Second, IVUS is helpful in assessing the correct entrance and exit of a wire into and out of the occlusion.14 Moreover, IVUS is especially important in dealing with PCI in ostial LAD and left main trifurcation. A major asset in the finally successful approach was the availability of the Corsair channel dilator, which could be advanced easily through the small collateral channel, graded as collateral connection grade 1 according to Werner et al.15 This catheter made a collateral dilatation unnecessary, made wire exchange easy, and gave a stable position for a superior wire control for the retrograde wire crossing of the CTO. As compared to microcatheters like FineCross, the latter would not follow a wire if the tapering collateral becomes to narrow relative to its outer diameter. It may be predicted, that this new device will facilitate intraluminal wire crossing more frequently, which should be preferred whenever possible to the subintimal techniques,7 as it would preserve the integrity of the vessel wall. Finally, this case demonstrates, that even the successfully passed wire may not secure the success of the procedure unless one can manage the necessary conversion from the retrograde to the antegrade approach. Here, the intracoronary use of snares may be helpful as described in this case. Flexible snares with 3-dimensional small loops which allowed good vessel coverage are ideal for intracoronary use. The externalization of the retrograde wire must be carried out with extreme care. These manipulations may cause deeper engagement of the retrograde guiding catheter which needs to be avoided to prevent ostial damage. The field of view should always include this catheter. Furthermore, when the stiffer shaft of the retrograde wire is advanced into the collateral channel, the collateral needs to remain protected by the presence of the microcatheter or the Corsair catheter, as in the present case. Otherwise, it would cut through the delicate wall of the collateral connections and may cause severe damage. When finally pulling back the retrograde wire, the microcatheter must protect the collateral channel until the soft wire tip is back in the collateral channel. The pulling back of the wire may be encountered with extreme resistance caused by the stiff part of the wire engaged in the collateral channel. Then, a gradual removal, synchronized with the heart beat, must be tried. After successful removal of the retrograde system, a careful angiographic demonstration of the integrity of the collaterals from orthogonal views, and to check for even small extravasations, needs to be performed via the retrograde catheter. In conclusion, if the clinical indication is sound, with expected clinical benefit for the patient, even repeated CTO recanalization attempts are justified. The retrograde approach requires a combination of different devices and techniques which all play an important role for the success of the procedure. Some specific issues encountered with new devices for the retrograde approach are discussed here, with practical tips and precautions. From *Department of Cardiology, Hospital Universitario Puerta de Hierro-Majadahonda, Madrid, Spain, and the §Department of Internal Medicine I, Klinikum Darmstadt, Darmstadt, Germany. The authors report no conflicts of interest regarding the content herein. Manuscript submitted June 19, 2009, provisional acceptance given July 6, 2009, final version accepted August 3, 2009. Address for correspondence: Gerald S. Werner MD, PhD, FESC, Direktor Medizinische Klinik I, Klinikum Darmstadt, Grafenstrasse 9, 64283 Darmstadt. E-mail: gerald.werner@klinikum-darmstadt.de

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