Large Thrombus in an Ectatic Big Right Coronary Artery

Prof. Ji-Young PARK

Nowon Eulji Medical Center, Eulji University, South Korea

A 44 year-old gentleman having a history of hypertension and was an ex-smoker, presented with a 3-day history of increasing chest discomfort. ECG on admission showed small Q waves in lead II, III, AVF. His cardiac enzymes were also elevated. Transthoracic echocardiogram showed apical akinesia with preserved LV systolic function (EF 57%). Diagnostic angiography revealed an ostial LAD stenosis and diffusely diseased mid to distal LCx (Movie 1, Movie 2). The RCA was large and ectatic with a suspicious thrombotic lesion in the distal RCA. A 6Fr JR4 guiding catheter was initially engaged into the RCA through the right femoral artery. However, the guiding catheter backup support was poor, therefore the RCA was then engaged with a 6 Fr AL1 guiding catheter (Movie 3). IVUS study showed there was large thrombus load in the distal RCA and the diameter was over 5mm (Figure 1). FilterWire EZ failed to pass through the tortuous mid-RCA. Distal protection device GuardWire balloon 5.5mm was able to be delivered to the distal RCA and aspiration thrombectomy was performed with Thrombuster 7Fr. Intracoronary GP IIb/IIa inhibitor was also given. However, distal flow did not improve significantly. Distal RCA was then pre-dilated with 4x15mm balloon and subsequently stented with 3 peripheral stents (6x24mm, 7x24mm, and 7x15mm, Figure 2). However, distal RCA flow did not improve after stenting and subsequently developed no reflow phenomenon (Movie 4). The patient developed severe chest pain, hypotension and bradycardia. Temporary transvenous pacing wire and IABP were inserted (Movie 5). Patient was stabilized and transferred to ICU for further care. Intravenous GP IIb/IIIa antagonist was given and chest pain subsequently subsided. Repeated angiogram 3 days later showed TIMI 0 flow in distal RCA (Movie 6). Repeated ECG showed established pathologic Q waves in inferior leads. The patient was subsequently discharged and remained asymptomatic afterwards.

Slow or no-reflow phenomenon can occur in elective or primary PCI. It is more commonly seen in PCI to a large ectatic RCA with high plaque or thrombus load. Distal embolic protection device can be used to minimize slow flow after balloon angioplasty and stenting. However, the device occasionally may not be able to be delivered to the desired position due to vessel tortuosity. Distal embolization may not be able to be prevented by distal protection device if the targeted lesion involves major side branches. Aspiration thrombectomy is usually used to reduce thrombus burden but sometimes it may not provide adequate aspiration to clear up large, organized clots or thrombus. Rheolytic thrombectomy devices may have an added benefit by providing additional mechanical fragmentation of the clot, resulting in better evacuation and aspiration of the thrombus. If aspiration fails to improve coronary blood flow, pharmacological agents such as intracoronary GP IIb/IIIa inhibitors or low-dose thrombolytic therapy have been used with success. Minimizing balloon angioplasty and direct coronary stent may reduce no reflow phenomenon. If no reflow occurs after PCI, intracoronary pharmacological agents such as nitroprusside, adenosine, adrenaline, or calcium channel blocker have been used with variable success. If all measures fail to improve coronary blood flow before stent implantation and the patient remains relatively stable, deferring coronary stenting may be a good option to prevent no reflow phenomenon if thrombus burden remains large.