Myocardial infarctions involving acute left circumflex occlusion: are all occlusions created equally?

Impact of acute total occlusion of the culprit artery on outcome in NSTEMI based on the results of a large national registry

BACKGROUND

The impact of acute total occlusion (TO) of the culprit artery in non-ST-segment elevation myocardial infarction (NSTEMI) is not fully established. We aimed to evaluate the clinical and angiographic phenotype and outcome of NSTEMI patients with TO (NSTEMITO) compared to NSTEMI patients without TO (NSTEMINTO) and those with ST-segment elevation and TO (STEMITO).

METHODS

Demographic, clinical and procedure-related data of patients with acute myocardial infarction who underwent percutaneous coronary intervention (PCI) between 2014 and 2017 from the Polish National Registry were analysed.

RESULTS

We evaluated 131,729 patients: NSTEMINTO (n = 65,206), NSTEMITO (n = 16,209) and STEMITO (n = 50,314). The NSTEMITO group had intermediate results compared to the NSTEMINTO and STEMITO groups regarding mean age (68.78 ± 11.39 vs 65.98 ± 11.61 vs 64.86 ± 12.04 (years), p < 0.0001), Killip class IV on admission (1.69 vs 2.48 vs 5.03 (%), p < 0.0001), cardiac arrest before admission (2.19 vs 3.09 vs 6.02 (%), p < 0.0001) and death during PCI (0.43 vs 0.97 vs 1.76 (%), p < 0.0001)-for NSTEMINTO, NSTEMITO and STEMITO, respectively. However, we noticed that the NSTEMITO group had the longest time from pain to first medical contact (median 4.0 vs 5.0 vs 2.0 (hours), p < 0.0001) and the lowest frequency of TIMI flow grade 3 after PCI (88.61 vs 83.36 vs 95.57 (%), p < 0.0001) and that the left circumflex artery (LCx) was most often the culprit lesion (14.09 vs 35.86 vs 25.42 (%), p < 0.0001).

CONCLUSIONS

The NSTEMITO group clearly differed from the NSTEMINTO group. NSTEMITO appears to be an intermediate condition between NSTEMINTO and STEMITO, although NSTEMITO patients have the longest time delay to and the worst result of PCI, which can be explained by the location of the culprit lesion in the LCx.

Submitral Aneurysm in a Patient with a Normal Electrocardiogram

A ventricular aneurysm entails well-known risks for the patient such as heart failure, potentially lethal arrhythmias, and systemic embolic phenomena. The submitral or posterolateral ventricular aneurysm is a very rare variety, usually of congenital etiology, which may also have other causes, including ischemic heart disease. The present case is about a 76-year-old male with the antecedent of an acute myocardial infarction 3 years ago. He presented with intermittent, brief, and self-limiting episodes of severe dyspnea, intense desperation, and accelerated palpitations, with a nonspecific electrocardiogram. An echocardiography revealed a large submitral aneurysm, with a good clinical response to the specific treatment of heart failure, antiarrhythmics, and oral anticoagulation therapy. We analyze the implications of an aneurysm in the context of an ischemic etiology, with special attention to the limitations of the electrocardiogram in the diagnosis of occlusions of the circumflex artery that irrigates the posterolateral region of the heart. We suspect that a greater number of patients with a culprit circumflex artery could receive appropriate coronary interventionism or thrombolysis if decision-making in the emergency room would not depend mainly on the electrocardiogram. Better stratification tools are needed to prevent late complications of infarction, such as those observed in this patient.

Incidence and impact of totally occluded culprit coronary arteries in patients presenting with non-ST-segment elevation myocardial infarction

The accuracy of the 12-lead electrocardiogram in detecting coronary artery occlusion is limited. We sought to determine the incidence, distribution, and outcomes of patients who have total occlusion of the culprit artery but present with non-ST-segment elevation myocardial infarction (NSTEMI). The randomized Acute Catheterization and Urgent Intervention Triage Strategy trial enrolled 13,819 patients presenting with non-ST-segment elevation acute coronary syndromes who underwent an early invasive strategy. The present study includes 1,319 patients with baseline biomarker elevation (NSTEMI) and no history of coronary artery bypass graft who underwent percutaneous coronary intervention of a single culprit vessel. We compared the baseline characteristics and outcomes according to whether the culprit vessel was occluded (baseline Thrombolysis In Myocardial Infarction [TIMI] 0 to 1) or patent (TIMI 2 to 3 flow) by angiographic core laboratory assessment. TIMI 0 to 1 flow in the culprit artery was present in 262 of 1,319 (19.9%) patients. The incidence of coronary occlusion was 28.4%, 19.3%, and 12.6% in patients with NSTEMI because of right coronary, left circumflex, and left anterior descending artery disease, respectively. Patients with an occluded culprit artery were more commonly men and had ST-segment deviation ≥1 mm. One-year outcomes, including death (3.5% vs 3.0%, p = 0.68) and myocardial infarction (8.4% vs 9.6%, p = 0.47), did not differ significantly between patients with versus without occluded culprit arteries, respectively. In conclusion, the present study demonstrates that the culprit artery is totally occluded in approximately 1 in 5 patients presenting with NSTEMI and single-vessel disease; however, the presence of total occlusion in NSTEMI was not associated with an incremental hazard of death or reinfarction at 1 year.