In-Stent Restenosis

KEY FEATURES

ESSENTIALS OF DIAGNOSIS

• Focal or diffuse intimal proliferation inside the stent or at the edges, resulting in restenosis

• Late luminal loss of ≥ 50% compared with acute luminal gain is generally considered in-stent restenosis (ISR)

• Recurrent angina or detection of ischemia in the vascular territory treated on stress tests Confirmed at angiography

GENERAL CONSIDERATIONS

• Stimulation of smooth muscle cells followed by proliferation and migration leads to neointimal thickening

• With plain balloon angioplasty, the ISR rate is 30–50%

• With bare metal stents, the ISR rate is between 20% and 30%

• With the advent of chemotherapy-coated stents (paclitaxel or sirolimus coated), the ISR rate is up to 9%, depending on the complexity of the stenoses treated

• Patient factors that increase the risk of restenosis:

  • – Diabetes mellitus

  • – Smoking

  • – Severe angina before stent placement

• Anatomic risk factors that increase the risk of ISR:

  • – Chronic total occlusion

  • – Saphenous vein grafts

  • – Long lesions

• Procedural variables that increase the risk of ISR:

  • – Post stenting minimal lumen diameter < 3.5 mm

  • – Use of first-generation stents (paclitaxel)

  • – Presence of thrombus

• Peak incidence is between 3 and 6 months

CLINICAL PRESENTATION

SYMPTOMS AND SIGNS

• May be asymptomatic

• Angina at rest or on exertion, sometimes worse than before intervention

• Dyspnea, leg edema may occur secondary to heart failure from ischemia

• Palpitations and syncope may occur as a consequence of arrhythmias

PHYSICAL EXAM FINDINGS

• Elevated jugular venous distention if heart failure present

• S₃ and S₄

• Bibasilar lung rales if heart failure present

DIFFERENTIAL DIAGNOSIS

• Symptoms early after stenting (< 1 month) usually mean in-stent thrombosis

• Symptoms late after stenting (> 9 months) usually mean progressive disease in nonstented segments

• Other causes of chest pain or positive stress tests may be found

DIAGNOSTIC EVALUATION

LABORATORY TESTS

• CBC, brain natriuretic peptide, troponin

ELECTROCARDIOGRAPHY

• ECG may show ischemic changes or myocardial infarction findings

IMAGING STUDIES

• Stress or vasodilator perfusion nuclear imaging

• Stress or dobutamine echocardiogram

DIAGNOSTIC PROCEDURES

• Coronary angiogram

• Optical coherence tomography to assess minimum luminal diameter or area

• Intravascular ultrasound imaging can also be used to assess the lesion lumen

TREATMENT

CARDIOLOGY REFERRAL

• All patients with suspected ISR should be evaluated by a cardiologist

HOSPITALIZATION CRITERIA

• If the presentation is unstable angina, myocardial infarction, or heart failure, hospitalization is required

• Following percutaneous coronary intervention (PCI) of ISR

MEDICATIONS