Heart Attack Types and Description of MINOCA Condition
MINOCA, or myocardial infarction with nonobstructive coronary arteries, is a lesser-known type of heart attack that occurs without any blockage in the arteries. This article aims to shed light on this condition, its causes, symptoms, and management.
Causes of MINOCA
MINOCA is often caused by coronary artery spasm, which describes the spontaneous tightening of a heart artery. Another common cause is the rupture, erosion, or ulceration of coronary plaque without significant artery blockage, leading to thrombus formation. Evidence suggests that myocarditis, an inflammation of the heart muscles, is present in 33% of MINOCA cases. Other less common causes include microvascular dysfunction, spontaneous coronary artery dissection, and supply-demand mismatch.
Differences with Traditional Heart Attacks
In contrast to traditional heart attacks (MI with obstructive coronary artery disease), MINOCA primarily involves plaque rupture, artery spasm, or microvascular dysfunction, causing less severe or transient blood flow disruption. Traditional heart attacks are typically caused by atherosclerotic plaque rupture or erosion, leading to infarction due to reduced blood flow.
| Aspect | MINOCA | Traditional Heart Attack (Obstructive CAD) | |-------------------------------|------------------------------------------------|-----------------------------------------------------| | Coronary artery status | Nonobstructive (<50% stenosis) | Obstructive (>50% stenosis, often near-total) | | Common mechanisms | Plaque rupture, artery spasm, microvascular dysfunction | Plaque rupture causing thrombus and artery blockage | | Patient profile | Often younger, more likely women, healthier baseline sometimes | Older, higher prevalence of classical risk factors | | ECG and biomarker findings | Usually milder ECG changes and lower troponin levels | Typical ECG changes (ST elevation or depression), higher troponins | | Symptoms | May present atypically, especially in women | Classic symptoms (chest pain, “elephant on chest”) |
Symptoms and Diagnosis
MINOCA symptoms are similar to those of heart attacks caused by other means, including chest pain, pain radiating elsewhere, shortness of breath, and nausea. However, they may present atypically, especially in women.
A doctor may use a variety of diagnostic tests to help exclude other possible causes of symptoms, such as coronary angiography, blood tests for troponin, ECG, coronary optimal coherence tomography, MRI, echocardiogram, and other diagnostic tests.
Risk Factors and Prevalence
MINOCA tends to occur more frequently in younger people and people assigned female at birth. Females are 5 times more likely to experience MINOCA than males. Potential risk factors for MINOCA may include an increased risk of blood clotting problems, anxiety and depression, cancer, autoimmune conditions, infectious diseases, hormones related to pregnancy, contraception, and hormone replacement therapy.
Management of MINOCA
The management of MINOCA depends on the underlying cause. A doctor may use beta-blockers, statins, clopidogrel, ACE inhibitors, angiotensin receptor blockers, calcium channel blockers, aspirin, or a combination of these treatments.
Spontaneous Coronary Artery Dissection (SCAD)
A noteworthy type of MINOCA is Spontaneous Coronary Artery Dissection (SCAD), which occurs when the wall of an artery suddenly tears, accounting for roughly a quarter of heart attacks in females under the age of 60 years.
In summary, MINOCA is a heart attack without significant coronary artery obstruction, often caused by coronary spasm or plaque events causing less severe or transient blood flow disruption. It is crucial to raise awareness about this condition, particularly among younger individuals and those assigned female at birth, to ensure timely diagnosis and appropriate treatment.
- In addition to coronary artery spasm and plaque rupture, science suggests that myocarditis, an inflammation of the heart muscles, is present in 33% of MINOCA cases, constituting one of the causes for this lesser-known type of heart attack.
- When comparing MINOCA to traditional heart attacks (MI with obstructive coronary artery disease), it's important to note that MINOCA primarily involves plaque rupture, artery spasm, or microvascular dysfunction, causing less severe or transient blood flow disruption.
- Risk factors for MINOCA may include an increased risk of blood clotting problems, anxiety and depression, certain medical-conditions such as cancer, autoimmune conditions, and infectious diseases, as well as hormones related to pregnancy, contraception, and hormone replacement therapy.
