HAU

A 59year old male presented with non-ST elevation myocardial infarction (NSTEMI). He is known to have hypertension, dyslipidemia and coronary artery disease (CAD) with history of coronary artery bypass graft (CABG) surgery and percutaneous coronary intervention (PCI) about two years ago. Procedure was done elsewhere, and no details were available. History of worsening effort angina for the last few months. Clinically he was stable with BP142/92 mm Hg, HR 105bpm andspO2 99%.

ECG showed sinus rhythm and T inversion in anterior leads. Initial cardiac Troponin was normal which peaked to a value of 248 ng/L subsequently. Renal function tests were normal. Echo showed normal EF (65%), no wall motion abnormalities, mild MR, TR and no PHTN. Patient was catheterized on next day after medical stabilization.

Coronary angiography was performed through right femoral arterial approach. Native vessel angiography revealed chronic total occlusion (CTO) from LAD ostium, severe proximal diffuse stenosis in an early OM with competitive flow from radial artery graft. Moderate to severe diffuse disease in proximal LCX. RCA had a patent stent in proximal segment, totally occluded small PDA and mild diffuse disease in PLV.

Graft angiography showed patent radial graft to principal OM. There was subtotal occlusion of left internal mammary artery (LIMA) graft to mid LAD anastomosis with severe lesions extending into native LAD resulting in faint antegrade flow. It was decided to carry out PCI of LIMA graft to LAD stenosis through LIMA graft conduit as native LAD had CTO.Through the right femoral access, a 6FInternal mammary artery (IMA) catheter was used to engage the LIMA ostium carefully and gently. A Sion blue coronary guide wire could be advanced through LIMA up to the lesion by gentle and careful manipulation. Though the LIMA was tortuous and redundant, there was only minimal accordion phenomenon without any significant flow limitations. The wire could not cross the lesions as it protrudes into multiple side branches. Then with a balloon support (1.2x12mm) and careful torquing, lesion could be crossed, and wire tip placed in apical LAD. Serial sequential pre-dilatations of the lesions were done with1.2x12mm,1.5x15mm, 2.0x12mm and 2.0x20mm SC balloons. Stenting of the lesion at LIMA-LAD anastomosis was done with a DES, 2.25x30mm Resolute Onyx at 12atm and post-dilated with a 2.5x15mm NC balloon at 16atm. Subsequent angiography after wire removal revealed TIMI3 flow with excellent myocardial blush and disappearance of accordion effect.

Left internal mammary artery is the gold standard graft conduit with proven high patency rate for bypassing the LAD in coronary artery bypass graft surgery. It has been shown to be more durable than other arterial and vein grafts with a patency rate of >90% at 10years. Percutaneous coronary intervention through LIMA conduit is challenging especially through tortuous, redundant LIMA graft and it is associated with high risk of mortality. Here we demonstrate a case of successful coronary intervention of LIMA graft -LAD anastomotic site through LIMA graft conduit by a gentle and careful approach using appropriate hardware.