Background:
The incidence of acute coronary syndrome (ACS) caused by left main coronary artery occlusion (LMCAO) is 0.37 to 0.9% and often associated with cardiogenic shock (CS) and high mortality. ACS with LMCAO requires emergency cardiac catheterization (ECC). The key point of management is rapid establishment of complete reperfusion. The current guidelines for ACS with ST- and non-ST-segment elevation myocardial infarction (STEMI/NSTEMI) recommend primary percutaneous coronary intervention (PCI) for hemodynamically unstable patients with CS. However, real-life data regarding acute outcomes of patients with ACS due to LMCAO are scarce. Thus, we conducted a single center analysis to evaluate in-hospital mortality of patients with ACS and LMCAO treated with PCI.

Methods and results:
All consecutive patients with ACS caused by LMCAO, who were treated with PCI between march 2020 and march 2022 at our institution, were retrospectively analysed regarding clinical outcome and in-hospital mortality.

2,281 patients were treated with PCI in our center. Of these, 46 patients had ACS due to LMCAO. 78.26% were male and the mean age was 74.1±12,2 years. STEMI (or equivalent) was present in 63.04% of the patients. Of the ACS patients with LMCAO, 6.8% required intrahospital and 19.56% prehospital cardiopulmonary resuscitation (CPR) with more than 30 minutes prehospital CPR in 33%. CS was present in 45.6%. Left ventricular circulatory support using an Impella® pump or extracorporeal membrane oxygenation (ECMO) was applied in 15.21% of the patients. 56.5% of all patients were treated with a provisional technique with one stent strategy. Coronary imaging such as intravascular ultrasound (IVUS) or optical coherence tomography (OCT) was used only in 6.5% of the cases. Primary revascularization was successful in 89.13 % of all patients presenting with ACS and LMCAO. Overall, in-hospital mortality was 36.95%.

Conclusions:
Our data highlight that patients presenting with ACS due to LMCAO are rare but have high mortality, particularly, case of CS or CPR. The key point of the management is rapid establishment of complete reperfusion.