How to ensure a coronary stent functions well in an adult patient with a history of coronary artery disease?

Ensuring Coronary Stent Function

To ensure a coronary stent is functioning properly, maintain dual antiplatelet therapy (DAPT) with aspirin plus a P2Y12 inhibitor for at least 12 months after drug-eluting stent placement, monitor for symptoms of stent thrombosis or restenosis, and use imaging-guided assessment (particularly optical coherence tomography) when stent dysfunction is suspected. 1

Optimal Medical Management for Stent Patency

Dual Antiplatelet Therapy Duration

• DAPT with aspirin plus a P2Y12 inhibitor must be continued for at least 12 months after drug-eluting stent placement to prevent stent thrombosis, which carries high morbidity and mortality. 2, 3

• Aspirin should be continued indefinitely at low dose (75-100 mg daily), as this is preferred over higher doses for long-term management. 3

• For patients with acute coronary syndrome at the time of stenting, more potent P2Y12 inhibitors (ticagrelor 90 mg twice daily or prasugrel 10 mg daily) are preferred over clopidogrel 75 mg daily. 2, 4

• Premature discontinuation of DAPT significantly increases the risk of stent thrombosis, which is why elective procedures should be deferred until completion of the recommended DAPT course. 2

Extended DAPT Considerations

• After a first stent thrombosis event, lifelong DAPT should be maintained if tolerated, as the long-term risk of recurrent stent thrombosis remains elevated. 1

• The European Society of Cardiology recommends using the DAPT score at 12 months to guide extended therapy duration, integrating both ischemic and bleeding risk factors. 1

• Patients with multiple risk factors for stent thrombosis (diabetes, multivessel disease, impaired left ventricular function, multiple or long stents, bifurcation stents) should be considered for prolonged DAPT beyond 12 months. 1, 5

Clinical Monitoring for Stent Dysfunction

Symptom Assessment

• Monitor for recurrent angina, which may indicate in-stent restenosis or thrombosis. New or worsening chest pain, particularly if it occurs at rest or with minimal exertion, warrants urgent evaluation. 6

• Watch for signs of acute coronary syndrome including ST-segment elevation on ECG, which can indicate acute stent thrombosis requiring immediate intervention. 1

• Assess for symptoms of heart failure (dyspnea, orthopnea, peripheral edema), as these may indicate compromised coronary flow affecting ventricular function. 6

Medication Adherence Verification

• Verify strict adherence to antiplatelet therapy at every clinical encounter, as nonadherence is a major contributor to stent thrombosis. 1

• Document any interruptions in DAPT, as even brief discontinuation (particularly in the first 12 months) dramatically increases thrombotic risk. 1

• Review all medications for potential drug interactions that could reduce antiplatelet efficacy, particularly proton pump inhibitors with clopidogrel. 3

Imaging-Guided Assessment of Stent Integrity

When to Pursue Advanced Imaging

• Optical coherence tomography (OCT) is the preferred imaging modality when stent dysfunction is suspected, as it can identify stent underexpansion, malapposition, positive remodeling, and thrombus formation. 1

• OCT should be considered when there is recurrent angina despite optimal medical therapy, as it can detect focal problems like edge evagination or incomplete stent apposition. 1

• Stent underexpansion or undersizing is a frequent contributor to stent thrombosis, and imaging-guided further expansion of the originally implanted stent is often indicated beyond simple vessel recanalization. 1

Coronary Angiography Indications

• Perform coronary angiography urgently if there are signs of acute stent thrombosis (acute chest pain with ST-segment changes, elevated cardiac biomarkers). 1

• Consider elective angiography for patients with recurrent symptoms despite optimal medical therapy to assess for in-stent restenosis. 1

• Fractional flow reserve (FFR) measurement can be used during angiography to functionally assess the significance of any stenosis, with FFR ≤0.80 indicating hemodynamically significant obstruction requiring intervention. 6

High-Risk Scenarios Requiring Vigilance

Multiple Stent Layers

• Patients with multiple overlapping stents (three or more layers) should never have DAPT interrupted, even remotely from the intervention, as observational data suggest persistently elevated thrombotic risk. 1

• Consider surgical revascularization rather than additional stenting when sequential stenting of the same lesion is required, particularly in the left anterior descending artery. 1

Very Late Stent Thrombosis

• Very late stent thrombosis (occurring >12 months after implantation) can occur even with newer-generation drug-eluting stents, particularly after DAPT discontinuation. 1

• Positive remodeling identified on OCT reinforces the importance of prolonging DAPT as much as tolerated, as this finding is associated with increased late thrombotic risk. 1

• If very late stent thrombosis occurs after DAPT discontinuation, re-implementing the previously administered P2Y12 inhibitor is reasonable. 1

Common Pitfalls to Avoid

• Do not routinely use platelet function testing or genetic testing to tailor antiplatelet therapy, as randomized trials have failed to show clinical benefit with management strategies based on these tests. 1, 3

• Avoid de-escalation of antiplatelet therapy intensity based on platelet function testing, as this approach lacks convincing evidence and is not routinely recommended. 1

• Do not prescribe nonsteroidal anti-inflammatory drugs chronically in patients with coronary stents, as these were excluded from major trials and may increase cardiovascular risk. 4

• Never delay urgent revascularization for stent thrombosis to obtain imaging, as immediate restoration of coronary flow takes priority over detailed anatomic assessment. 1