Introduction
Sudden cardiac death is often the result of underlying atherosclerotic changes, where the vessels that hold the blood flow exhibit changes in their walls. The blood vessel walls acquire a firmer and rougher texture due to the gathering of fat-like materials over the inner aspect of the walls. This plaque gathering, in turn, shrinks the lumen for blood flow. Once the dimension of the lumen diminishes, it gets reflected in the form of compromised blood flow.
When atherosclerotic changes develop in the blood vessels concerned with the nourishment of cardiac muscles, the oxygen-deprived heart muscles will die out. This is projected as heart attacks, strokes, and other cardiovascular events. Atherosclerotic changes are attributed to more than half of cardiac complications. However, a minor segment of cardiac diseases can bring sudden death to a person with no underlying atherosclerotic changes. Non-atherosclerotic coronary artery disease accounts for less than seven percent of the total myocardial infarctions (diminished or complete cessation of blood flow to heart muscle cells) and three percent of sudden cardiac death cases.
What Is Non Atherosclerotic Coronary Artery Disease?
Non-atherosclerotic coronary artery disease is a peculiar spectrum encompassing diversified and chaotic heart diseases, which have no association with atherosclerotic changes in the cardiac blood vessels. These cardiac abnormalities are reported to have a close association with cardiac maladies like cardiac arrest (restricted cardiac blood supply), sudden cardiac death (death occurs within one hour following the cardiac event), myocardial ischemia (oxygen depreciation in cardiac muscles), and myocardial infarction.
Younger populations are reported to have a higher frequency of non-atherosclerotic coronary artery disease than older populations. However, it can develop in an individual of any age range. In non-atherosclerotic coronary artery disease, cardiac complications arise due to defects in impairment involving the coronary artery other than the atherosclerotic coronary artery disease. Having obvious cardiac manifestations in non-atherosclerotic coronary artery disease is unnecessary.
What Are the Etiological Factors Associated With Non Atherosclerotic Coronary Artery Disease?
A wide range of causative factors can influence the development of non-atherosclerotic coronary artery disease. Disease or defect affecting the coronary artery apart from atherosclerosis is identified to have a decisive role in developing non-atherosclerotic coronary artery disease. Some of the fundamental etiological factors include the following disease conditions:
1. Congenital Anomalies in the Coronary Artery: Inborn aberration or abnormality in the coronary artery is reported to be the key etiology for non-atherosclerotic coronary artery disease. The defectively formed coronary artery may remain undetected until an apparent cardiac event occurs. Post-mortem studies of individuals who have had a sudden cardiac death either during physical activity or at rest exposed the presence of inborn abnormalities in the coronary artery. Coronary arterial aberration can be structural or functional defects that influence how the heart performs its roles.
2. Coronary Artery Dissection: It is rare for the coronary artery to develop a break or split. The dissection allows the flowing blood to seep in between the arterial layers. The percolated blood then gathers over there, producing a node-like bulge, with the projection directed inwards. This bulge collapses the luminal dimension and constricts the passage for blood flow. Short breath, fainting, heart racing, chest pain, and enhanced sweating are a few of the manifestations elicited in coronary artery dissection.
3. Coronary Artery Vasculitis: An inflammatory condition develops over the arterial wall. It is often accompanied by puffing up of the artery wall, which occludes and narrows down the lumen. Coronary artery vasculitis may indicate underlying disease conditions called polyarteritis nodosa, a blood vessel ailment specifically targeting medium and small-sized arteries.
4. Coronary Artery Spasm: It is also identified to be a causative factor for non-atherosclerotic coronary artery disease. Coronary artery spasm, as the name suggests, develops to the contraction or shrinking of the muscles that build the coronary artery wall. This tightening diminishes the size of the arterial lumen, thereby restricting the blood flow through it.
5. Fibromuscular Dysplasia: It is an unfamiliar and less frequently reported disease condition that typically affects medium-sized arteries. In fibromuscular dysplasia, there will be an exponential upsurge in the cellular growth rate in the affected arterial wall. The more cell volume in the arterial wall collapses the arterial lumen, thus diminishing the passage for blood flow.
6. Idiopathic Arterial Calcification of Infancy: It is an inborn arterial disease where the artery walls tend to develop calcifications. Idiopathic arterial calcification of infancy is reported to have a strong connection with alteration in a specific gene.
How Is Non Atherosclerotic Coronary Artery Disease Treated?
There is no single treatment option for this array of disease conditions. The underlying etiological factor needs to be identified before designing the treatment strategy. Various diagnostic tools like echocardiograms, electrocardiograms, magnetic resonance imaging, magnetic resonance angiography, coronary angiography, intravascular ultrasound, and X-rays provide a detailed picturization of the hidden anomaly.
Accordingly, the treatment intervention should be planned to deal with the etiological factors. Prompt identification and treatments are essential, as it can precipitate sudden cardiac death if left unattended. The treatment focuses on reinstating patent blood flow through the coronary artery. Stent placement is an effective treatment modality for coronary artery dissection to open up the arterial lumen. In some instances, surgical bypassing of the involved arterial portion is done to re-establish the blood flow to the heart muscles.
Coronary artery vasculitis is often approached with medical management using corticosteroids and immunosuppressants. A transluminal angioplasty procedure is advised for fibromuscular dysplasia of the coronary artery to compensate for arterial shrinking. Likewise, the treatment plan differs according to the cause; hence, it is essential to figure out the exact leading cause of the condition.
Conclusion
Non-atherosclerotic coronary artery disease is a less explored and obscured cardiac entity. Studies have reported that around half of the patients with non-atherosclerotic coronary artery disease flagged typical cardiac symptoms like chest pain. In contrast, the other half failed to elicit any cardiac manifestations. Early diagnosis is the key that aids in enhancing the prognosis as well as the patient’s longevity. Advancements in the diagnostic aspects often assist in timely detection and ensure prompt treatment.
