A 56-year-old woman presented with an acute inferior ST-segment elevation myocardial infarction. She was treated with intravenous metoprolol, heparin and eptifibatide, along with oral clopidogrel and aspirin. Emergent cardiac catheterization revealed a thrombotic total occlusion of the mid to distal right coronary artery (Figure 1), with no significant disease of the left coronary system. Left ventricular function was mildly depressed with mild inferior hypokinesis. Percutaneous coronary intervention proceeded with easy wire passage and immediate but faint opacification of the distal vessel. An Export thrombectomy catheter (Medtronic Inc., Santa Rosa, CA) was advanced distally over the guide wire. Subsequent pretreatment with intracoronary nitroprusside (total of 200 mcg) was then administered into the distal coronary through the aspiration lumen, according to previously described methods.1 Three runs of manual Export aspiration were conducted with recovery of a small quantity of thrombotic material. The distal vessel was now visualized, with Thrombolysis in Myocardial Infarction (TIMI) grade 3 flow, revealing a 90% stenosis at the site of previous occlusion. A 3.0 x 16 mm Taxus drug-eluting stent (DES) (Boston Scientific Corporation, Natick, MA) was easily deployed (Figure 2), resulting in no residual stenosis (Figure 3). The artery continued into a posterior descending branch, without evidence of bifurcation into a posterolateral branch. The patient had an uneventful post-infarct course and was subsequently discharged after 2 days.
Eighteen months later, she presented with complaints of substernal chest pressure and dyspnea on exertion, reminiscent of her prior symptoms. Although no objective evidence of ischemia or infarction were evident, decision was made to proceed directly to cardiac catheterization for a definitive diagnosis in light of her previous history. Again, no significant disease was seen in the left coronary system. Right coronary angiography revealed a widely patent stent with excellent TIMI grade 3 flow. However, a new patent posterolateral branch was now seen originating from the mid-section of the stent. It was then obvious that the stent had been deployed at the crux, across the previously occluded posterolateral branch (Figure 4). The patient was continued on long-acting metoprolol, ramipril, aspirin, clopidogrel, and atorvastatin; pantoprazole was added for possible gastrointestinal symptoms. She was discharged the same day and has remained asymptomatic.
Percutaneous treatment of coronary bifurcation lesions (BL) has been fraught with technical challenges. Many techniques, such as Y-stenting, T-stenting, crush stenting, and kissing stents have been proposed for this anatomic subset; however, none have resulted in uniform long-term patency of both branches. 2-6
Interestingly, the opposite scenario occurred spontaneously in our patient. No attempt was made during the initial intervention to access the posterolateral branch, as its presence was concealed by the flush occlusion. Along with anti-thrombotic and anti-platelet therapy, the normalized perfusion from thrombectomy-assisted stenting of the main artery may have improved flow dynamics into the side-branch. That unintended simultaneous thrombectomy occurred in the posterolateral branch was unlikely, as it remained occluded at the end of the intervention. While stent-induced plaque shifting usually results in side-branch compromise, our patient may have demonstrated a rare case of favorable snow-plowing into an adjacent wall, eventually liberating the posterolateral ostium.
Occasionally, a stump or ostial nub and/or delayed distal opacification of an occluded branch can be seen during angiography. An assessment should then be made regarding the potential benefits and feasibility of revascularization of that vessel. Had the side-branch been detectable during our initial intervention, a double-wire technique with either kissing balloons or dual-vessel stenting would probably have been considered. Ironically, it is unlikely that this more complicated procedure would have yielded a superior long-term result than the one obtained. Thus, while painstaking measures are often undertaken to preserve a diseased but patent side branch, occasionally simply treating the main vessel can unexpectedly open a previously occluded one. This branch liberation by deployment of stent jail is an unexpected, but certainly welcomed commuted sentence.
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Note: This article underwent double-blind peer review by members of the Cath Lab Digest Editorial Board.
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