Treatment of High-Burden Thrombus in a Large Right
Coronary Artery

Case Report. A 30-year-old male with no previous medical history presented to an emergency department at a community hospital with left-sided, substernal chest pain. The pain was pressure-like and nonradiating. It began shortly after performing weight-lifting activity and lasted for more than 2 hours. In the emergency department, the patient was initially treated medically with aspirin and intravenous nitroglycerin, resulting in partial relief of the chest pain.
The patient was hemodynamically stable and physical examination, including cardiac auscultation, was unremarkable. An electrocardiogram showed normal sinus rhythm with 0.2 mV ST-segment depression in the inferior leads associated with deep T-wave inversions. A troponin-I assay was markedly positive with a value of 52.9 mg/dl (normal reference: < 0.4 mg/dl). In addition, a fasting lipid panel revealed severe dyslipidemia with a low-density lipoprotein level (LDL) of 255 mg/dl and a highdensity lipoprotein level (HDL) of 24 mg/dl.
The patient was diagnosed as having a non-ST-segment elevation myocardial infarction (NSTEMI) and was subsequently treated with unfractionated heparin, clopidogrel, metoprolol and atorvastatin. A diagnostic cardiac catheterization was performed 48 hours into his initial presentation after transfer to a tertiary care facility.
Selective arteriography of the left coronary arteries was performed with a 6 Fr Judkins Left 4 (JL-4) diagnostic catheter (Medtronic, Inc., Minneapolis, Minnesota). The left main coronary artery was angiographically normal. There was a 30% stenosis in the mid-portion of the left anterior descending artery after the second diagonal branch. The left circumflex artery was angiographically normal. A 6 Fr Judkins Right 4 (JR-4) Launcher guide catheter (Medtronic) was advanced to the ostium of the right coronary artery (RCA). Contrast injection of the RCA revealed a very large-caliber dominant vessel. A large filling defect, consistent with TIMI grade 4 thrombus, was visible from the mid-portion of the vessel extending down into the posterolateral ventricular (PLV) and posterior descending artery (PDA) branches (Figure 1). There was good flow of contrast around the thrombus and TIMI 3 flow in the distal vessel.

After obtaining central venous access through the right femoral vein, a 5 Fr Pacel^™ balloon-tipped temporary pacemaker wire (St. Jude Medical, Minnetonka, Minnesota) was advanced into the right ventricular apex from the right femoral vein and found to have adequate capture.
Intraprocedural anticoagulation was achieved with a bolus (0.75 mg/kg calculated to 82.5 mg) and infusion (1.75 mg/kg/hour calculated as 192.5 mg/hour) of bivalirudin (Angiomax^®, The Medicines Company, Parsippany, New Jersey). In addition, a bolus (180 μg/kg calculated to 20.4 mg) and infusion (2 μg/kg/minute calculated to 13.6 mg/hour) of eptifibatide (Integrelin^®, Schering-Plough, Kenilworth, New Jersey) were administered.
A Maverick^® 3.0 mm x 12 mm Rapid Exchange angioplasty balloon (Boston Scientific, Natick, Massachusetts) was advanced over an Asahi Prowater 0.014 inch x 180 cm guidewire (Abbott Laboratories, Abbott Park, Illinois), which had been previously positioned in the PLV branch. The balloon was inflated to 12 atm for 30 seconds at the proximal portion of the filling defect (Figure 2A). Balloon angioplasty was attempted initially to ascertain the diameter and length of the lesion to facilitate stent placement. In addition, angioplasty was performed with the intention of facilitating passage of a thrombectomy catheter, given that the patient presented for coronary angiography 36 hours after his initial symptoms and the increased likelihood of organized thrombus. Test injections showed no significant distal embolization and the patient maintained a sinus rhythm (Figure 2B).
A Pronto aspiration catheter (Vascular Solutions, Minneapolis, Minnesota) was then advanced over the guidewire to the bifurcation of the PLV and PDA branches. Distal-to-proximal aspiration was performed twice and multiple fragments of thrombus were obtained. Notably, the filling defect was much smaller in appearance, especially in the mid-portion of the vessel (Figure 2C).
Quantitative coronary analysis of the vessel documented a vessel diameter of 5.6 mm. We performed intravascularultrasound (IVUS) with the 2.9 Fr 150 cm Eagle Eye Gold catheter (Volcano Therapeutics, Rancho Cordova, California) to verify the size of the vessel. IVUS demonstrated a luminal diameter of 8 mm in the mid-portion of the vessel with a large amount of thrombus and soft plaque (Figure 3). The distal vessel, including the bifurcation of the PLV and PDA branches, appeared to contain a high burden of thrombus (Figure 2C).

After thrombectomy, a large degree of thrombus was still present and overlying a 75% stenotic lesion. Therefore, we opted to place a stent over the mid-portion of the RCA in order to prevent future clot embolization and propagation. The 6 Fr JR-4 Launcher guide catheter was exchanged for an 8 Fr Launcher JR-4 guide catheter (Medtronic). The mid-RCA lesion was recrossed with an Extra S’port 0.014 inch x 300 cm guidewire (Guidant Corp., Santa Clara, California). An 8.0 x 27 mm balloon-expandable Express Biliary stent (Boston Scientific Corp., Natick, Massachusetts) was deployed at 8 atm (for a final diameter of 8.0 mm) to the mid-RCA without complication (Figure 4).
The patient subsequently received 48 hours of treatment with eptifibatide. Repeat catheterization was performed revealing continued presence of filling defects and TIMI grade 4 thrombus at the bifurcation of the PLV and PDA branches (Figure 5). After using Angiomax in the same fashion as above, an 8 Fr Launcher JR-4 guide catheter was advanced into the ascending aorta and engaged into the ostium of the RCA. A 0.014 inch x 180 cm Asahi Prowater guidewire was placed in the PLV and another identical wire was placed in the PDA. The ostium of the PDA was dilated with a 3.0 x 12 mm Maverick balloon to 12 atm. Then a 5.0 x 20 mm Liberté stent (Boston Scientific) was deployed at 18 atm (for a final diameter of > 5.62 mm). Further injections revealed a 90% stenosis at the ostium of the PDA. Dilatation of this lesion with a 3.0 x 9.0 mm Maverick balloon at 16 atm was followed by the deployment of a 4.0 x 12 mm Liberté stent at 14 atm (for a final diameter of 4.36 mm), resulting in the treatment of this bifurcation with the “T-stent” technique. There was TIMI 3 flow, no dissection and no residual thrombus in the distal RCA (Figure 6). The patient had an uneventful hospital course and has had no further recurrence of his chest pain.