PCI, widely known as angioplasty with stenting, is a common, minimally invasive procedure used to treat coronary artery disease by opening blocked heart arteries. A catheter is guided from a peripheral vessel, typically in the wrist or groin, up to the heart to compress plaque and place a mesh tube, or stent, to restore blood flow. While effective and generally safe, patients should understand the full range of potential complications. These risks can manifest immediately at the access site, during the procedure, or long after the intervention is complete.
Vascular Access Site Complications
The site where the catheter is inserted, usually the radial artery in the wrist or the femoral artery in the groin, is the most frequent location for minor complications. Bleeding and hematoma formation are the most common issues. A hematoma is a localized collection of blood outside the vessel. While minor bruising is expected, a large hematoma can cause pain or require a blood transfusion, particularly with the femoral approach.
More serious, albeit rare, local complications include the formation of a pseudoaneurysm, which is a tear in the artery wall leading to a pulsatile blood sac. Another risk is an arteriovenous (AV) fistula, an abnormal connection between the artery and an adjacent vein. These complications may require specialized treatment, such as ultrasound-guided compression or surgical repair.
Acute Cardiac and Procedural Risks
The most immediate risks are those directly related to the manipulation inside the coronary artery during the intervention. One complication is a periprocedural myocardial infarction (MI), a heart attack occurring during or immediately following the PCI. This can happen if the balloon inflation shifts plaque fragments, blocking a smaller downstream vessel, or if a side branch of the coronary artery becomes unintentionally occluded.
The mechanical forces exerted by the balloon or stent can cause a coronary artery dissection, a tear in the inner lining of the vessel wall, or a full coronary perforation. A severe dissection can lead to abrupt closure of the artery. A perforation can cause blood to leak into the sac surrounding the heart, a life-threatening condition called cardiac tamponade. In less than one percent of cases, these vessel injuries may necessitate an urgent shift to open-heart surgery, known as emergency Coronary Artery Bypass Grafting (CABG).
Acute stent thrombosis is a severe complication, defined as the rapid formation of a blood clot that completely blocks the newly placed stent within the first 24 hours. The risk is minimized by administering antiplatelet medications before and immediately after the procedure. Irregular heart rhythms, or arrhythmias, can be triggered during the intervention, often by the mechanical irritation of the heart muscle by the guidewire or catheter. While some arrhythmias are transient and resolve quickly, others, such as ventricular fibrillation, can be life-threatening and require immediate electrical cardioversion.
Systemic Risks Associated with PCI
Some complications of PCI involve a systemic effect extending beyond the heart or the access site. Contrast-Induced Nephropathy (CIN) is a temporary impairment of kidney function caused by the iodine-based contrast dye used to visualize the arteries under X-ray. The incidence of CIN can range from 10% to over 20% in high-risk patients, such as those with pre-existing kidney disease or diabetes.
The risk of CIN is mitigated by ensuring the patient is well-hydrated before and after the procedure to help flush the dye from the system. Patients may also experience allergic reactions to the contrast dye. These reactions range from mild symptoms like itching and hives to severe, though rare, anaphylaxis, and are typically managed with medications like antihistamines or steroids.
The procedure requires the use of fluoroscopy, which involves continuous X-ray imaging. This results in patient exposure to ionizing radiation. While modern equipment and careful technique keep the dose low for most patients, the dose is carefully monitored. The risk is generally low for a single procedure but is a consideration for patients who require multiple or complex interventions.
Delayed Stent Failure
Complications can also emerge weeks, months, or years after a successful PCI, representing a delayed failure of the treatment. The most common delayed issue is restenosis, which is the gradual re-narrowing of the treated artery segment. This occurs when an excessive amount of scar tissue, or neointimal hyperplasia, forms inside the stent in response to the initial injury.
Drug-eluting stents (DES) significantly reduced the rate of restenosis compared to older bare-metal stents by slowly releasing medication to inhibit this tissue growth. Late or very late stent thrombosis, which is the formation of a clot within the stent long after the procedure, remains a risk. This event is often associated with the premature discontinuation of prescribed dual antiplatelet therapy (DAPT).
The antiplatelet medications, such as aspirin and a P2Y12 inhibitor, are necessary for a period of months or even years to ensure the stent surface is fully covered by a healthy layer of cells, preventing clot formation. Non-compliance with this medication regimen is the most significant preventable factor leading to delayed stent thrombosis, a complication that carries a high risk of heart attack and death.