Clinical Information Relevant Clinical History and Physical Examination: A-55-year old gentleman with background comorbidities of diabetes mellitus chronic kidney disease and hypertension initially presents with central chest pain. Respiratory examination demonstrates minimal fine crackles on both lower zones. Otherwise, hemodynamic parameters are normal. Immediate medical therapy for Non ST elevation acute coronary syndrome is initiated. 

Electrocardiogram demonstrates sinus rhythm with Q wave at V2-V3 and poor R wave transition, while troponin is elevated at 19,000. Echocardiogram shows dilated left ventricle with left ventricular ejection fraction of 36%. 8 left ventricular segments are hypokinetic. Non ST elevation myocardial infarction is diagnosed. Subsequent SPECT myocardial perfusion imaging demonstrates 5 non viable segments of left circumflex territory, and 2 segments of left anterior descending territory 

Diagnostic coronary angiogram via the right femoral artery using a 6Fr Judkins Left 4.0 demonstrates a CTO of the proximal LAD and 99% stenosis of the mid-distal LCX. This is followed by a coronary angiogram using Judkins Right 3.5 that demonstrates the presence of 80-90% stenosis of the proximal RCA, 80-90% stenosis of both the PLV and PDA. The distal RCA contributes bridging collaterals to the LAD.

Subsequently, decision was made to intervene the LAD CTO via an antegrade approach via single puncture strategy. Angioplasty began by engaging a 7Fr Judkins Left 4.0 to the left coronary ostium. Wiring was initially performed using a Sion Blue through a Fine Cross microcatheter which was unsuccessful as the wire was only able to tunnel the CTO cap but could not advance further down. As a result, the wire was changed to Gaia Second via trapping ballon technique using Genoss 2.5 x 12 inflated at 12 atm. At this stage, Gaia Third was passed through a Sasuke double lumen catheter acting as a support wire. As a result, Gaia Second was able to be tunneled through the CTO reaching the distal LAD. Angiographic image captured confirmed the location of the wire within the true lumen. Serial predilation was performed using Sapphire 0.85 x 5, followed by Pantera Pro 1.25 x 15 at 14 atm, and finally Sapphire 2.0 x 15. Satisfactory expansion was achieved with a non flow limiting (Type B) dissection. DCB was eventually deployed with Magic Touch 2.25 x 40 at 8 atm for 60 seconds leading to a fully restored main vessel together with its side branches. Subsequent outpatient follow up review revealed improvement of left ventricular ejection fraction to 45%.

This case illustrates the key interventional strategies when dealing with intervention of CTO. Wire crossing through the CTO lesion is crucial since only successful wiring could further permit balloon crossing. Several additional techniques to aid in successful wire crossing include ballon over wire support, microcatheter and stiff wire usage can be implemented. However, extreme caution should be taken when using stiff wires as the risk of subintimal wiring resulting in the creation of false lumen may happen. Finally, avoiding creation of false lumen is the utmost important aspect to pre-empt unwanted subintimal balloon dilation which may result in devastating coronary perforation.