Our patient is a 63 years old gentleman with known past history of hypertension, T2DM, hypercholesterolemia. He is a non-smoker. 
He was admitted to our hospital for unstable angina, suffering from chest pain for 1 month prior to hospitalization with increasing frequency. He had a private CT coronary angiogram done showing triple vessel disease with high calcium score (significant stenosis in proximal and mid LAD, proximal LCx, proximal and mid RCA).
Physical examination was unremarkable

ECG showed sinus rhythm with no acute ischemic changesRepeated blood tests for elevated cardiac troponin came back negative.Transthoracic echocardiogram showed normal left ventricular systolic function without regional wall motion abnormality.

Diagnostic coronary angiogram showed a right dominant system, with involvement of left main and triple vessel disease.
Breakdown as followdistal LM 70%LAD diffuse calcified vessel with proximal LAD 80% stenosisproximal Ramus 90% stenosisproximal LCx 90% stenosis but small vesselproximal RCA 50%

Left coronary system was engaged with 7Fr EBU 3.5 guiding catheter.
Our initial strategy was upfront LM/LAD/LCx bifurcation stenting by DK-CRUSH plus drug-eluting balloon to Ramus.However we soon found out that we failed to pass any balloon catheters through LCx lesion, despite using smallest 0.85 semi-compliant balloon. In view of small-sized vessel, we decided for medical therapy to LCx and we altered our stenting strategy to upfront LM/LAD/Ramus DK-CRUSH bifurcation stenting.
We proceeded according to the standardized steps for performing DK-CRUSH. The whole process was under intravascular ultrasound (HD-IVUS) guidance and it went smoothly.We then performed post-stenting IVUS study. Unfortunately, the IVUS got stuck after studying Ramus and was unable to be retrieved. We immediately stopped pulling. Then we tried different maneuvers for rescuing stuck IVUS. First we tried to push IVUS catheter forward gently and then together with some rotation hoping to free the stuck part, but was unable to solve the problem.Next we removed the imaging core and inserted a harder Grandslam wire as well as 0.018" wire hoping to provide a better force and remove it en-bloc, but once again we failed.Our next move was to cut the IVUS shaft and deploy a 5Fr ST01 guiding-extension catheter in a mother-and-child fashion to cover the whole IVUS catheter and coronary wire and by this maneuver we successfully retrieved the IVUS intact.
We then completed the remaining part of the procedure uneventfully.

According to Murphy's Law, anything that can go wrong will go wrong.It is inevitable that interventional cardiologists come across complications during procedures as long as they perform interventions on patients. Of course being able to avoid complications from happeneing will be ideal, but sometimes it is not the case. Therefore it is of paramount importance to be well-preparaed for every possible outcome and to embrace the knowledge and techniques to get yourself out of the difficult situation should it really occur.Our case illustrated different methods used to retrieve stuck HD-IVUS catheter and we hope to share our experience and knowledge in this topic with colleagues worldwide.