Aortic Root and Extensive Coronary Dissections Complicating Recanalization of Chronic Right Coronary Artery Occlusion: Refrainin

The incidence of chronic total occlusions (CTO) is between 20–40% in patients with angiographically documented coronary artery disease.1 Percutaneous coronary intervention (PCI) for chronic total occlusion is associated with a significantly lower success rate and a higher complication rate compared to PCI for subtotal stenoses. Despite improved procedural success and the development of new interventional devices, CTOs remain the lesion subset with the lowest success rate because of the inability to cross the lesion with a guidewire.2 Difficulties during advancement of the guidewire beyond the occlusion in the absence of antegrade flow include determining the exact course of the occluded vessel, crossing the entire length of the occlusion and determining the optimal wire manipulations. During the wire maneuvers, the subintimal passage of a guidewire tip may cause a localized dissection, with the creation of a false lumen and eventually coronary perforation. In addition to possible coronary wall damage and complications related to attempts to find the true vessel lumen, there are risks associated with guiding catheter trauma to the coronary ostium or aortic root. We report a case of coronary and aortic root dissection following attempted recanalization of CTO in the right coronary artery (RCA) with a favorable follow-up. Case Report. A 54-year-old man was admitted for elective recanalization of CTO of the RCA in December 2001. Past medical history included previous inferior myocardial infarction and coronary angioplasty (PTCA) with stenting of the circumflex artery in August 1998. The patient was angina free for 3 years, but subsequently had a recurrence of angina on effort with an equivocal exercise stress test in August 2001. He had undergone an unsuccessful recanalization attempt of the proximal CTO RCA in another institution in October 2001, two months prior to his current admission, and was referred to our institution for persistence of symptoms. Current coronary angiography showed proximal RCA occlusion (Figure 1). To allow for good back-up during recanalization, an 8 French (Fr) left Amplatz guiding catheter (Cordis Corporation, Miami, Florida) was used to selectively cannulate the RCA. Attempts were made to cross the occlusion using the 0.014´´ Athlete standard guidewire (Asahi Intec. Co. Ltd., Seto, Aichi, Japan) and 0.014´´ Choice PT guidewire (Boston Scientific/Scimed, Inc., Maple Grove, Minnesota) supported by a 1.5 mm Maverick coaxial balloon (Boston Scientific/Scimed, Inc.). All attempts were unsuccessful. Finally, after cautious manipulation using a Conquest wire (Asahi Intec. Co. Ltd.), a passage was made into the distal RCA. Contrast injection revealed that the wire passage was subintimal. Attempts to re-enter the true lumen were unsuccessful, with evidence on repeat contrast injection of dissection in the RCA and a small area of contrast hang-up at the RCA ostium. The contrast progressed into a peri-ostial aortic root dissection following a forceful injection from the guide catheter (Figure 2). The dissection appeared to be limited, with no evidence of aortic regurgitation, and the patient was clinically and hemodynamically stable. In order to create some flow to the distal vessel, the Conquest wire was advanced into the distal RCA toward the posterolateral branches, with the hope of breaking into a true distal lumen. The advancement of a guidewire to provide a distal re-entry for the occlusive dissection was done in an attempt to establish forward flow. This action was based on our prior experience utilizing this approach in such situations. Following multiple attempts and without the perception of a successful result, the procedure was stopped. The decision was thus made to manage the dissection conservatively. The patient was discharged on aspirin, with clinical and angiographic follow-up arranged 3 months later. At the time of follow-up, the patient was clinically well and free of angina. Repeat angiography revealed complete spontaneous healing of the peri-ostial aortic root dissection. Furthermore, there was remarkable recanalization of the chronic RCA occlusion with good anterograde flow to the distal RCA (Figure 3). The patient was discharged the following day feeling well and remains asymptomatic. Discussion. The reported case of aorto-ostial dissection complicating attempted recanalization of RCA occlusion is interesting because the conservative management resulted in favorable clinical and angiographic follow-up. In this case, the most likely cause of the aorto-ostial dissection is trauma provoked by the guiding catheter (a left Amplatz) associated with retrograde propagation of the dissection from the RCA. This latter event was probably caused by the forceful dye injection. Aortic root dissections are usually surgically managed. Moles et al. described 2 cases of aortic dissection.3 The first case was limited to the aortic root and the second was associated with severe aortic regurgitation and small pericardial effusion during an attempted recanalization of a subtotal occlusion of the mid RCA, requiring urgent surgical repair. Ochi et al. described 2 cases of retrograde dissection that were limited in the aortic root and aortic arch, requiring urgent surgical repair.4 Pande et al. reported a case of dissection of the RCA and retrograde extension into the ascending aorta requiring emergency surgical repair in a patient of histological evidence of cystic medial necrosis in the ascending aorta.5 Sutton et al. described a case with retrograde dissection of the aorta, necessitating urgent surgical repair, that occurred during an attempt to open an occluded right coronary artery.6 However, some cases have been treated with coronary artery stenting, avoiding the need for emergency surgical repair. Alfonso et al. described 2 cases of localized aortic dissection following attempted PTCA to the RCA; the patients underwent multiple stenting to avoid cardiac surgery, although the second patient was later referred for elective coronary bypass surgery.7 Wadgi et al. reported catheter-induced dissection of the RCA ostium extending to the aortic root, which was managed with a dacron stent-graft in the proximal RCA, although the patient later underwent elective surgical repair.8 Rarely, conservative management of aortic root dissections complicating PCI is employed. A report by Perez-Castellano et al. described 3 cases of dissection limited in the right sinus of Valsalva that were conservatively treated.9 Pentousis et al. reported a case of an extensive type A aortic dissection that occurred during an attempt to recanalize a CTO of the RCA that was conservatively treated, with follow-up of 36 months.10 The reported cases of aortic dissections related to coronary artery angioplasty or attempts to recanalize CTOs have been mostly associated with the RCA (Table 1). All described aortic dissections were type A according to the Stanford classification.11 It is well known that management of dissection progressing further into the aortic root during PTCA or attempted recanalization of CTO depends on stability of the aortic dissection and the stability of the distal vessel. Both of these conditions were present in our case, and the patient was asymptomatic. The decision to conservatively treat the dissection was based on our previous experience with such dissections healing spontaneously. Nevertheless, the recanalization of the RCA was an unexpected finding. It is conceivable that the further mechanical extension of the dissection distally with possible communication with the distal vessels may have facilitated establishment of forward flow and contributed to healing of the dissection. The patient remained well and asymptomatic. The diagnostic techniques currently recommended to follow patients with aortic dissections include aortography, contrast-enhanced computed tomography, magnetic resonance imaging, transthoracic echocardiography and transesophageal echocardiography. We prefer transesophageal echocardiogram instead of aortography or other techniques because we feel it is a safe and accurate method to follow patients with aortic dissection, in order to assess aortic valve function and progression of aortic dissection. It is important to point out that avoidance from placing any stent helped the spontaneous maintenance and expansion of the “best true lumen”. The true vessel lumen seen at the follow-up angiography had not appeared as such at the end of the recanalization procedure. The eventual use of stents, if deployed in a false lumen, could have sealed this lumen, preventing blood flow to direct the healing of the dissection according to the best pathway. Of course, the option of conservative treatment was possible because the patient was clinically stable.

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