A coronary stent is a small, mesh-like tube placed in a blocked heart artery to open it up during a procedure called angioplasty. The stent acts as a scaffold, pressing plaque against the artery walls and restoring blood flow to the heart muscle. For most patients, this intervention is successful, relieving symptoms like chest pain and preventing heart attacks. While the procedure has a high success rate, it is not without risks.
Primary Medical Causes
The primary cause of sudden death after a stent is placed is an event called stent thrombosis. This occurs when a blood clot forms on the surface of the stent, suddenly and completely blocking the artery again. This blockage prevents blood from reaching the heart muscle, leading to a major heart attack, which can be fatal.
Stent thrombosis is categorized based on when it occurs. Acute thrombosis happens within the first 24 hours after the procedure. Subacute thrombosis occurs between 24 hours and 30 days. Late stent thrombosis is defined as occurring more than 30 days after the stent was implanted. In many fatal cases, there is a failure to form a complete layer of smooth tissue, called neointima, over the stent struts, leaving the metal exposed to the blood.
Beyond a clot forming directly in the stent, other medical events can lead to sudden death. The heart attack caused by stent thrombosis can trigger malignant arrhythmias, which are fast or irregular heartbeats that prevent the heart from pumping blood effectively. In other cases, the underlying coronary artery disease can progress in other arteries that were not treated with a stent. A plaque in one of these other vessels can rupture, causing a new heart attack separate from the stented area.
Timeline and Associated Risk Factors
The risk of a fatal complication is highest in the immediate period following the procedure. The first 30 days are considered the most vulnerable time, with mortality rates reported to be as high as 50% for patients who experience a stent thrombosis within this early window. After this initial month, the risk decreases as the vessel begins to heal over the stent’s surface. Beyond the first few months, the increased risk of mortality directly related to the stent diminishes.
Certain patient characteristics can increase the risk of complications.
- Diabetes, advanced kidney disease, or those who continue to smoke
- The complexity of their heart disease, such as blockages in multiple arteries, in very small vessels, or in the left main coronary artery
- The initial reason for the stent, such as being in the middle of a large heart attack
Procedural factors also contribute to the level of risk.
- The use of very long stents or multiple overlapping stents
- Placing a stent across the opening of a major side branch of a coronary artery
- If the stent is not fully expanded to press firmly against the artery wall, it can create areas where blood flow is disturbed
The Role of Antiplatelet Medication
Following a stent procedure, patients are prescribed a combination of medications known as Dual Antiplatelet Therapy (DAPT). This includes aspirin and a second medication like clopidogrel, ticagrelor, or prasugrel. These drugs work by making platelets less sticky, which is important for preventing them from clumping together to form a clot on the metal surface of the new stent.
The stent is a foreign object, and the body’s natural response is to form a clot around it. Antiplatelet medications directly counteract this process, giving the artery wall time to grow a new, smooth layer of cells over the stent. This healing process, called endothelialization, can take weeks or months. During this period, DAPT serves as a protective measure against stent thrombosis.
The premature discontinuation of DAPT is a leading preventable cause of stent thrombosis and subsequent heart attack or death. Patients may be tempted to stop their medication due to side effects, cost, or a misunderstanding of its purpose. Stopping these medications, even for a single day, can have severe consequences and should never be done without a cardiologist’s approval.
Post-Procedure Warning Signs
The most important warning sign is the return of chest pain, pressure, or discomfort, especially if it feels similar to the symptoms experienced before the procedure. This could indicate that the stent has become blocked or another artery is in trouble. Pain that radiates into the jaw, neck, back, or down one or both arms is another sign of a heart attack.
Other symptoms also warrant immediate medical attention, such as new or worsening shortness of breath, which may signal that the heart is not pumping effectively. Sudden dizziness, lightheadedness, or fainting can be a sign of a heart rhythm disturbance. Feeling the heart race or skip beats, known as palpitations, should also be treated as an emergency.
If any of these warning signs appear, it is important to call emergency services immediately. Time is critical when dealing with a potential heart attack, as faster treatment leads to better outcomes. Waiting to see if symptoms improve can result in irreversible damage to the heart muscle or a fatal event.