Background: 

Left main coronary artery occlusion (LMCAO) in acute myocardial infarction (AMI) is a rare condition with extremely high mortality and a reported incidence of 0.37 to 0.9% in patients with AMI undergoing emergency cardiac catheterization (ECC). Cardiogenic shock is a grave prognostic marker in AMI. Although the guidelines are controversial for the best management approach for LMCAO, both percutaneous coronary angioplasty (PCI) or coronary artery bypass graft (CABG) for unprotected LMCAO have been reported. However, these patients either had stable coronary artery disease (SCAD) or supporting collateral flow (CF). We report 2 cases with primary PCI in an acute subtotal LMCAO without CF from the right coronary artery (RCA) and without any left ventricular assist device (LVAD).

Case description: 

Case 1: 

A 79–year old female, past smoker with previous medical history (PMH) of SCAD and granulomatosis polyangiitis with involves of multiple organ systems was admitted to another regional hospital because of kidney failure. During hospitalization, she developed new-onset severe chest pain and was transferred as an emergency to our center. At admission, she was normotensive and had sinus tachycardia. The ECG showed alternating ST segment elevation in aVR, diffuse ST segment depressions alternating with left bundle branch block (BBB) (Fig. 1) The patient underwent ECC. Using a 6 F guiding catheter, CTO of RCA was demonstrated (Fig.2) and the proximal left main (LM) was subtotally occluded (Fig.3). Using hydrophilic guidewires in LAD and RCX (Fig.4) a drug eluting stent (DES) was deployed after predilation of the LM with proximal optimization technique (POT); a good acute angiographic(Fig.4).  result was achieved. 

Case 2: 

A 84–year old male without PMH of SCAD was admitted as an emergency due to acute onset of severe chest pain. He initially presented with hypotension and sinus tachycardia. The ECG showed alternating ST segment elevation in aVR and right BBB. (Fig. 5) The patient underwent ECC  using a 7 F guiding catheter, demonstrating CTO of the RCA (Fig.6).The distal LM was subtotally occluded with a Medina 1-1-1 bifurcation lesion (Fig. 7). We deployed 2 drug eluting stents with final POT in double kissing crush technique with a good acute angiographic results. 

Impella and extracorporeal membrane oxygenation (ECMO) were considered in both cases but left for stand-by because of a rapid successful coronary intervention. Emergency pre-interventional echocardiography showed moderately impaired systolic left ventricular ejection fraction (LVEF) in Case 1 and normal LVEF in Case 2. However, both patients developed acute respiratory failure requiring noninvasive ventilation. Both patients had no further complications, did not require invasive ventilation and were discharged from hospital after 10- in case 1 and 14 days from cardia care unit  in 2 case. 

Conclusion: 

There is limited experience with PCI of an acute LMCAO without CF from the RCA and thus, the management of LMCAO in this setting remains controversial. Key point of the management is rapid complete reperfusion. Current evidence suggests that PCI may be non-inferior to CABG in the management of acute LMCAO. PCI has the advantages of rapid reperfusion to critically ill patients, often those with prohibitive risk for CABG, with acceptable short- and long-term outcomes. These 2 cases of AMI with acute LMCAO were successfully managed with PCI without the help of any LVAD system.