Stent thrombosis
Introduction
Stent thrombosis is a serious complication that can occur after the placement of a coronary stent in the arteries of the heart. This condition is characterized by the formation of a blood clot (thrombus) within the stent, which can lead to a sudden and severe blockage of the artery. This can result in acute coronary syndrome, including myocardial infarction (heart attack), and can be life-threatening.
Pathophysiology
The pathophysiology of stent thrombosis involves several complex processes. The placement of a stent can cause injury to the arterial wall, triggering an inflammatory response. This can lead to the activation of platelets and the coagulation cascade, resulting in the formation of a thrombus. The risk of stent thrombosis is highest in the first few days after stent placement, but it can occur at any time, even years after the procedure. The risk is particularly high in patients with acute coronary syndrome, diabetes, renal failure, and in those who are non-compliant with antiplatelet therapy.
Risk Factors
Several factors can increase the risk of stent thrombosis. These include technical factors related to the stent placement procedure, such as incomplete stent expansion, stent malapposition, and residual dissection. Patient-related factors include advanced age, diabetes, renal failure, and acute coronary syndrome. Medication-related factors include non-compliance with antiplatelet therapy and the use of certain types of drugs, such as thienopyridines.
Diagnosis
The diagnosis of stent thrombosis is typically made based on clinical symptoms, electrocardiographic changes, and elevated cardiac biomarkers. Coronary angiography is the gold standard for confirming the diagnosis. This procedure involves the use of X-ray imaging to visualize the coronary arteries and the stent. In cases of suspected stent thrombosis, it can reveal a filling defect within the stent, indicating the presence of a thrombus.
Treatment
The treatment of stent thrombosis is a medical emergency and typically involves urgent coronary angiography and percutaneous coronary intervention (PCI). This may involve balloon angioplasty to open the blocked stent, and/or the placement of a new stent. In some cases, emergency coronary artery bypass graft surgery may be required. Medical treatment includes the use of antiplatelet drugs and anticoagulants to prevent further clot formation.
Prevention
The prevention of stent thrombosis involves several strategies. These include the use of drug-eluting stents, which release medication to prevent clot formation, and the use of dual antiplatelet therapy, typically aspirin and a P2Y12 inhibitor. Other preventive measures include careful stent placement to avoid technical errors, and patient education to ensure compliance with medication.
Prognosis
The prognosis of stent thrombosis is generally poor, with a high risk of myocardial infarction and death. However, outcomes can be improved with prompt diagnosis and treatment. Long-term prognosis depends on several factors, including the patient's overall health, the extent of the coronary artery disease, and the success of the treatment.