Abstract
Funding Acknowledgements
Type of funding sources: None.
The widespread use of coronary angiography (CAG) in patients with acute coronary syndrome led to the understanding that in some patients myocardial infarction (MI) occurs against angiographically unchanged or slightly modified coronary arteries (CA). In such cases, the so-called "type 2 IM" is diagnosed in some patients, however, to determine the true cause of MI, a modern method of investigation such as optical coherence tomography (OCT) is needed to visualize the intima of the CA and detect a minimal atherosclerotic process.
The purpose of the study was to establish the etiology of MI without obstructive coronary artery disease (MINOCA) using OCT.
Materials and methods
160 conclusions of the OCT were analyzed. In 9 (6%) cases, the study was conducted in patients who underwent proven MI (mean age 43,1 ± 13,2, 8 males, 1 female) who had no hemodynamically significant CA stenosis according to CAG data.
Results
in 2 cases (22%) patients had ST-elevation MI, thrombotic occlusion of the CA (in one case, thrombaspiration was performed). In both patients, spontaneous dissection of the intima of the unmodified CA was detected in the OCT. The remaining 7 patients had non-ST-elevation MI, and in 2 cases, a diagnosis of type 2 MI was established: in both patients, the atherosclerotic plaque was visualized, narrowing the lumen of the CA less than 50%, in one case MI developed against a background of the hypertensive crisis, in another - against a background of spasm of CA. In the remaining 5 patients, OCT revealed subintimal atheromatous, with elements of local dissection of the intima. Thus, in 78% of patients atherosclerosis of CA of different severity (from the subintimal deposition of lipids to the development of atherosclerotic plaque, narrowing the clearance of the SC by less than 50%) was diagnosed. In the analysis of risk factors for coronary heart disease (CHD), 57% of patients with atheromatous CA had more than 2 risk factors for CHD: 3 (42%) smoked, 5 (71%) - obesity, 4 (57% ) - had arterial hypertension, 3 (42%) had dyslipidemia, 1 (14%) had type 2 diabetes. In the group of patients with spontaneous intima dissection of the CA, 1 patient (woman) did not have CHD risk factors, the 2-nd suffered from obesity and hypertension. For all patients a lifestyle correction was recommended; statins, antiplatelets were prescribed, patients with spontaneous dissection of CA had the recommendation of examination in the medical-genetic center.
Conclusion
Based on the results of the study, in most cases, the cause of IMBOC development was an atherosclerotic lesion of the coronary arteries, which is not always visualized with standard coronary angiography. Basically, the patients were young and middle-aged. Most patients had different risk factors for coronary heart disease.
Mast cells are increased in the media of coronary lesions in patients with myocardial infarction and may favor atherosclerotic plaque instability
