Background: The left circumflex (LCx) artery is the most diagnostically challenging of the coronary branches in terms of diagnostics because the clinical presentation and electrocardiography (ECG) do not always suggest critical occlusion despite its presence. Therefore, it is important to determine the factors contributing to the clinical manifestation and outcome, such as the culprit location.
Aims: To determine the relationship between the location of the culprit plaque and clinical outcomes in the LCx artery.
Methods: Data from the Polish Registry of Invasive Cardiology Procedures (ORPKI) from the years 2019-2020 concerning percutaneous coronary intervention (PCI) procedures were extracted and analyzed using appropriate statistical tests.
Results: 97 899 clinical records were analyzed. Patients with proximal occlusion received a worse grade using the Killip classification. Patients with Thrombolysis in Myocardial Infarction (TIMI) score 0 had worse clinical presentation in each of the occlusion locations. The periprocedural cardiac arrest and death rates were the highest among patients with proximal circumflex (Cx) occlusion. The death rate among patients with proximal occlusion and non-ST-segment elevation myocardial infarction (NSTEMI) was greater than among patients with distal occlusion and ST-segment elevation myocardial infarction (STEMI).
Conclusions: Among patients with proximal occlusions of the Cx artery and TIMI 0 grade flow on initial angiogram, a STEMI-like approach should be undertaken apart from initial ECG findings. This is driven by a higher rate of critical and fatal complications such as cardiac arrest and periprocedural death. Fatal complications occur more often in patients with proximal occlusion of Cx than in medial or distal occlusion. Grade IV according to the Killip classification can suggest a proximal culprit location.
Keywords: Killip classification; acute coronary syndromes; clinical outcomes; culprit lesion; left circumflex artery.