Percutaneous Coronary Interventions (PCI)

PTCA is done via percutaneous femoral, radial, or brachial artery puncture. The radial approach reduces patient discomfort, improves time to ambulation, and reduces the incidence of some complications (eg, bleeding, pseudoaneurysm formation).

A guiding catheter is inserted into a large peripheral artery and threaded to the appropriate coronary ostium. A balloon-tipped catheter, guided by fluoroscopy or intravascular ultrasonography, is aligned within the stenosis, then inflated to disrupt the atherosclerotic plaque and dilate the artery. Angiography is repeated after the procedure to document any changes. The procedure is commonly done in 2 or 3 vessels as needed.

Stents for coronary arteries are expandable wire mesh cylinders that help hold stenotic areas open. Stents are most useful for

• Short lesions in large native coronary arteries not previously treated with PTCA

• Focal lesions in saphenous vein grafts

• Treatment of abrupt closure during PTCA

Angioplasty Stent

Image

Stents are used frequently for acute myocardial infarction, ostial or left main disease, chronic total occlusions, and bifurcation lesions.

Various anticoagulation and antiplatelet regimens are used during and after PCI to reduce the incidence of thrombosis at the site of balloon dilation and stent placement.

Anticoagulation is usually initiated with unfractionated heparin. Enoxaparin and bivalirudin are alternatives. Bivalirudin or argatroban should be used in place of unfractionated heparin in patients with heparin-induced thrombocytopenia. Dual antiplatelet treatment with P2Y12 inhibitors (clopidogrel, prasugrel, ticagrelor) and aspirin is started at the time of the procedure in patients undergoing percutaneous coronary intervention. Glycoprotein IIb/IIIa inhibitors (abciximab, eptifibatide, tirofiban) may be added in patients with unstable non-ST-segment elevation myocardial infarction periprocedurally. P2Y12 inhibitors (often in combination with aspirin) are continued for at least 6 to 12 months after PCI to decrease the risk of in-stent thrombosis until endothelialization of the stent has occurred.

For patients who require anticoagulation for another reason (eg, atrial fibrillation), direct-acting oral anticoagulants (apixaban, dabigatran, edoxaban, or rivaroxaban) are preferred long-term over warfarin, unless there is a contraindication to them. For most patients requiring anticoagulation, triple therapy with oral anticoagulation, P2Y12 inhibitor, and aspirin is stopped within 1 week to 1 month after intervention, and patients are continued on oral anticoagulation and a P2Y12 inhibitor for 6 months to 1 year. Calcium channel blockers and nitrates may also be given to reduce risk of coronary spasm.

Relative contraindications to PCI include

• Coagulopathy

• A single diseased vessel providing all perfusion to the myocardium

• Critical left main coronary stenosis without collateral flow from a native vessel or previous bypass graft to the left anterior descending artery

• Diffusely diseased vessels without focal stenoses

• Hypercoagulable states

• Lack of cardiac surgical support

• Stenosis < 50%

• Total occlusion of a coronary artery

Although lack of cardiac surgical support is sometimes considered an absolute contraindication to PCI, many experts advocate that when revascularization is required urgently in STEMI, experienced operators in approved catheterization laboratories should proceed with PCI even if surgical backup is not available.

Although bypass is typically preferred for patients with critical left main coronary stenosis without collateral flow from either a native vessel or previous bypass graft, PCI is often and increasingly being used in this scenario in selected patients.

The main complications of balloon angioplasty and stent placement are

• Arterial dissection

• Bleeding caused by adjunctive anticoagulation

• Restenosis

• Standard complications of cardiac catheterization and coronary angiography

• Thrombosis and distal embolization

Overall, risks of undergoing PCI are comparable to those of CABG. Overall mortality rate is < 1%, but varies based on individual risk factors and tends to be similar to that of CABG; Q wave MI rate is < 1%. In < 1% of patients, intimal dissection causes obstruction requiring emergency CABG. Risk of stroke with PCI is lower than with CABG. A meta-analysis of 19 randomized trials reported a higher risk of stroke in patients undergoing CABG (1.2%) than PCI (0.34%,) at 30 days (1). Risk of bleeding is 1 to 2%.

Of all angiographic procedures, PCI has the highest risk of contrast nephropathy (due to increased contrast load and procedural time); this risk can be reduced by preprocedural hydration and possibly by use of a nonionic contrast agent or hemofiltration in patients with preexisting renal insufficiency.

Compared to coronary angiography without angioplasty or stent placement, risk of death, MI, and stroke is greater.

Clinical Calculators

PTCA Mortality Prediction