The patient was a 56-year-old man with a history of dyslipidema and three-vessel coronary artery disease. He underwent LAD stenting in 2017 at an outside institute, and CTOs in LCx and RCA were left untreated. He remained clinically uneventful until a traffic accident in Oct 2020, resulting in multiple bone fractures, hemothorax and liver hemorrhage. He was immediately transferred to our hospital for transarterial embolization to address the liver hemorrhage.

Five hours after transarterial embolization, he developed acute-onset chest pain. The ECG revealed new ST elevation in the precordial leads, accompanied by elevation of troponin I levels. Emergent coronary angiography revealed acute thrombotic occlusion in the proximal LAD stent and CTOs in the LCx and the RCA. Aspiration thrombectomy and small balloon dilation were performed to restore LAD flow with a reduced dose heparin to avoid recurrent bleeding. 

After stabilization, the patient underwent a staged procedure to assess the LAD stent and to address the LCx CTO. The proximal cap of the LCx CTO was ambiguous (type 2 bifurcation CTO). Proximal cap puncture was performed with IVUS-guided parallel wiring.  Another parallel wiring was successfully performed to enter distal true lumen. IVUS revealed deformed proximal LAD stent struts, which were restored under realtime IVUS-guided wiring. 

Another staged procedure was conducted for the mid and distal RCA CTOs. Following antegrade preparation, a retrograde approach was employed via the septal collateral channel. To address the large angle of attack at the exit of the distal RCA CTO at the bifurcation, a dual lumen catheter was retrogradely utilized. Successful retrograde wiring reached a contrast island at the junction of segments 2 and 3. Navigating the tortuosity of the mid RCA CTO involved the use of a retrograde knuckle wire. Tip-in and Intracoronary Rendezvous techniques become necessary as both the antegrade and retrograde microcatheters encountered difficulty crossing the mid RCA CTO. IVUS revealed intraplaque tracking in both the mid and distal RCA CTOs. 

1. The cause of LAD stent thrombosis in the patient may be due to interrupted antiplatelet agent and systemic inflammation in the presence of malapposed stent struts.2. Revascularization of multivessel CTO should be considered to avoid catastrophic outcomes that may occur in the last remaining coronary artery.3. The use of IVUS is crucial for stent optimization, troubleshooting, and guidance in complex CTO PCI. 4. CTOs involving proximal (type 2) and distal bifurcations (type 4) require complex techniques to preserve important side branches. 5. Dual lumen catheter could be retrogradely utilized for distal CTO cap puncture and retrograde parallel wiring.