Dr Sridhara G, Consultant – Interventional Cardiology, Cardiac Electrophysiology, Manipal Hospital Old Airport Road explains about Coronary Artery Calcification and available treatment methods for this issue
Calcification in the coronary arteries is a sine qua non of the presence of atherosclerotic blocks or cholesterol deposits in the blood supply of the heart. Calcification can occur anywhere in the vascular system of the body, including the blood vessels that supply blood to the heart and brain. The most common cause of this is the duration of the cholesterol block itself, as the chronicity of the atherosclerotic process continues to increase and the calcification of that atherosclerotic block becomes very high.
Why Coronary Artery Calcification (CAC) is common in men?
CAC is a cholesterol blockade of the artery. This condition is more prevalent in men because most have risk factors for developing atherosclerotic cholesterol deposits in the blood supply like hypertension, diabetes, smoking, etc. In addition, the likelihood of calcification or cholesterol deposits increases dramatically with age.
Males have a higher prevalence of coronary artery disease and atherosclerotic vascular diseases than females. Females are protected until menopause due to monthly hormonal cycles that prevent cholesterol deposition. Typically, cholesterol deposition in women begins after menopause (from about 50 years of age). Thus, when women over 60 are diagnosed with heart disease, the duration of cholesterol deposition is shorter than in men, in whom cholesterol deposition increases over decades beginning at 30-40 years of age. As a result, more males present with cholesterol atherosclerotic vascular narrowing.
Treatment methods for CAC
Coronary angioplasty is the most common procedure a Cardiologist performs to open cholesterol blocks in the heart’s blood supply. It is a technical procedure in which the cholesterol blocks are dilated with standard balloons to open up channels and the stent is placed to prevent the re-collapse of an expanded artery with a balloon.
However, calcium is a tough material. Unlike cholesterol blocks which are soft and at best fibrotic, calcium blocks are very hard. Calcium can be so horrendous that it can be present in all the layers of the blood vessel, requiring a considerable amount of tools and devices to crack it open in order to achieve good expansion, which is necessary for good long-term results following the angioplasty.
With the advancement in the field of cardiac science, there are effective tools to crack open calcium so that the final vessel diameter can result in better long-term outcomes after balloon angioplasty and stenting. These are special balloons with small blades that penetrate the calcified blocks and crack them open.
Another frequently used method to break open calcium is rotablation. It burrs through the coronary artery at high speed, pulverising the calcium and transforming it into very small debris that will be absorbed by the circulation system. Once the calcium inside the cholesterol block is pulverised, other balloons are used to open the blood vessel and place the stent. This is one approach.
Intravascular Lithotripsy is another emerging process to treat CAC. It is well known that since decades ago, ultrasonic vibrations are largely used to crack or dissolve calcified kidney stones. For this process, a certain tool is inserted into the coronary artery’s narrowing or calcified block while activating the sonic vibrations. Different balloons have different sets of pulses and when pulses are delivered, the sonic vibrations permeate the blood vessel wall and crack open the calcium. Once the calcium is broken, other balloons such as cutting balloons can be used to further break it open. Due to its hardness, calcium decreases the blood vessel’s elasticity. The blood vessel’s elasticity returns after the calcium are broken down, allowing the cardiologist to insert stents of the appropriate size to keep the vessel open for an extended period of time.
High-pressure balloons are also offered for this process. Sometimes calcium blocks are so tough that even after using all other tools to break them open and implanting the stent, the diameter of the stent achieved may be inadequate. In such cases, high-pressure balloons, which can reach pressures of 40 to 45 or 50 atmospheres are used, as opposed to normal balloons, which can reach pressures of 15 – 20 to 24 atmospheres. These are double-layered, latex-coated balloons that can withstand extremely high pressures, allowing one to open an under-expanded stent, a very high calcified or very difficult block in the coronaries without using any other available tools.
The technology today has advanced to the point where we can now perform angioplasty and stenting of highly calcified lesions, which were previously reserved for surgical procedures.
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