Why arteries calcify – and what modern medicine can do about it

By definition, the term arteriosclerosis refers to the deposition of fats and cholesterol in the walls of blood vessels . "Arterio" comes from the ancient Greek "artería," "vein," and "sclerosis" from "sklerós," "hard." Literally, arteriosclerosis is a "hardening of the arteries," meaning the hardening of the blood vessels that carry blood away from the heart.

Incidentally, the term 'arteriosclerosis' is often used colloquially. However, this isn't entirely accurate, because unlike, for example, a calcified washing machine hose, it's not limescale that is deposited, but rather a mixture of cholesterol and cholesterol-like substances, fats, calcium salts, and connective tissue . Furthermore, these deposits aren't found on the inner wall of the artery, but actually within the wall.

Atherosclerosis is by far the most important factor in the development of cardiovascular disease. This makes it the most significant risk factor for premature death due to heart attacks, strokes, and other conditions.

Dr. Stefan Waller is a specialist in internal medicine and cardiology. He offers online coaching for patients with heart disease and provides weekly updates on the latest developments in cardiology. He is part of our EXPERTS Circle . The content represents his personal perspective based on his individual expertise.

A stent is a small, tubular vascular support made of fine metal mesh. It is inserted into a narrowed or blocked coronary artery to permanently maintain open blood flow to the heart muscle. The stent acts like an internal scaffold: It supports the vessel wall from within and prevents the vessel from narrowing again after it has dilated.

A stent is always inserted when a narrowing in the coronary artery restricts blood flow so severely that the heart muscle no longer receives sufficient oxygen and nutrients. This can occur acutely in a heart attack due to a sudden complete blockage of a coronary artery, or in chronic coronary artery disease with recurring symptoms such as the typical angina pectoris chest pain resulting from reduced blood flow to the heart muscle.

A thin plastic tube (catheter) is carefully advanced to the affected coronary artery via an arterial access at the wrist (radial artery). To precisely locate the narrowing, X-ray contrast medium is injected and an X-ray examination is performed simultaneously.

A small balloon is carefully inflated at high pressure at the narrowed area, known as the stenosis. This pushes the plaque deposits against the vessel wall, widening the vessel from within. The folded stent rests on the balloon, which expands during inflation and is pressed into the narrowed artery wall.

When the balloon is removed, the stent remains in the vessel as a fine metal framework. It keeps the vessel wall open, allowing blood to flow unhindered to the heart muscle.

Stent implantation is one of the most frequently performed medical procedures worldwide today, especially for the treatment of narrowed coronary arteries. Although the procedure is considered minimally invasive and safe, various complications can occur during the procedure.

Possible complications during the procedure include:

1. Bleeding at the puncture site, especially if blood thinning is necessary at the same time
2. Vascular injuries, for example due to incorrect placement or when advancing the catheter.
3. Thromboembolic events, e.g., caused by detached plaque fragments, which can lead to a heart attack or stroke.
4. Allergic reactions to the contrast agent or the stent material.
5. Cardiac arrhythmias.
6. In very rare cases: acute stent thrombosis immediately after insertion, requiring immediate reintervention.

Long-term risks : if the stent causes problems:

Complications can occur even weeks or months after implantation. The most common include:

1. In-stent restenosis: This is a renewed narrowing of the vessel due to scar tissue growth within the stent. Modern drug-eluting stents significantly reduce this risk.
2. Late stent thrombosis: Despite modern technology, a blood clot can form in the stent months or years later. This complication is rare but potentially life-threatening.
3. Infections in the area of ​​the stent: These occur only in exceptional cases, but can be dangerous because the foreign material can be a breeding ground for bacteria.
4. Allergies to the metal used (e.g. nickel) – a rare but possible cause of discomfort after implantation.

After stent implantation, targeted drug therapy and structured follow-up care are essential to prevent complications such as stent thrombosis and improve the long-term prognosis. Antiplatelet therapy (DAPT) is the standard treatment, which typically involves a combination of aspirin and clopidogrel (if a stent is implanted during a heart attack, additional antiplatelet drugs are also used).

The duration of DAPT depends on the indication and the risk of bleeding. For ACS, treatment is currently recommended for 12 months, while for coronary artery disease (CAD) only 3-6 months. However, recent study data show advantages for a shorter duration of DAPT, allowing the treating cardiologist to decide on the duration of DAPT on a much more individual basis. Dual antiplatelet therapy (DAPT) is usually followed by long-term single-agent therapy (monotherapy) with aspirin.

Additional medications are considered in individual situations; for example, oral anticoagulants are used if atrial fibrillation is present in addition to coronary heart disease. However, the duration and other factors are highly variable, so this must be decided on a case-by-case basis.

Short-term follow-up care after stent implantation takes place on the hospital ward. This includes pulse, mobility, sensitivity, and wound checks. Laboratory tests monitor coagulation parameters, signs of inflammation, and other findings, and early mobilization is initiated with physiotherapy and vascular training.

In the long term, secondary prevention, i.e., the prevention of recurrence, is crucial . Lifestyle changes such as smoking cessation, improved nutrition, and, ideally, daily exercise lay important foundations for long-term treatment success and the prevention of complications. Controlling blood pressure, blood lipid, and blood sugar levels is also an important lever that can significantly influence the prognosis. Optimizing risk factors can significantly reduce the risk of recurrence of cardiovascular complications.

New, ultra-thin, drug-coated stents significantly reduce the risk of reocclusions or other problems in the treated narrowings, known as stenoses, especially in the first three years after the procedure.

Different stent materials and coatings also allow for a shorter duration of double antiplatelet therapy than previously used "bare-metal" stents, for example, in patients with a high bleeding risk. Drug-coated balloons (DCBs) without an overlying stent are also used as a "stent-free" option, especially in cases of in-stent restenosis (a narrowing that has recurred within the implanted stent) and small vessels. The advantage is that there is no need for a new permanent implant and the duration of the necessary double antiplatelet therapy is often shorter.

Despite all the "stent high-tech": the long-term prognosis, i.e. life expectancy and quality of life, depends crucially on the consistent improvement of the causative lifestyle, because the causative arteriosclerosis (medically more correctly: atherosclerosis) cannot be "stented away."

In the context of a heart attack, when a coronary artery suddenly becomes blocked and occluded, the implantation of a stent into the blocked coronary artery is a highly beneficial technique that saves lives or at least quality of life by protecting the heart attack patient from death or subsequent heart failure. However, the stent does not address the cause; it only eliminates the acute narrowing or blockage. As described above, the cause can only be addressed through sustained lifestyle adjustments and the correct management of our risk factors.