A Comprehensive Guide to Percutaneous Coronary Intervention

A Comprehensive Guide to Percutaneous Coronary Intervention

Percutaneous Coronary Intervention (PCI) is a minimally invasive therapeutic procedure that adopts cardiac catheterization techniques to dilate stenotic or occluded coronary arteries and improve myocardial perfusion. This technique covers balloon angioplasty, stent implantation and coronary artery assessment procedures, and can achieve millimeter-level precise manipulation with the assistance of vascular interventional robots.
Technical Classifications
1. Percutaneous Coronary Angioplasty (PTCA)
Via femoral artery or radial artery access, a guiding catheter is delivered to the ostium of the target coronary artery, followed by advancing a matched balloon along the guide wire to the stenotic segment. Appropriate pressure and duration are applied for dilation to relieve vascular stenosis.
Nevertheless, standalone PTCA carries relatively high risks of acute coronary occlusion and restenosis. Acute occlusion mostly occurs within 24 hours post-operation with an incidence rate of 3%-5%, which may trigger acute myocardial infarction or even death. Restenosis generally develops within 6 months after surgery at a rate of 25%-50%, causing recurrent angina pectoris and often requiring revascularization. Due to such limitations, it is rarely used alone in clinical practice nowadays.
2. Coronary Stent Implantation
Mesh-shaped stents made of stainless steel or alloy materials are implanted into the stenotic coronary segments to support vascular walls and maintain unobstructed blood flow. This approach can reduce vascular elastic recoil after PTCA, seal vascular dissections induced by balloon dilation, and markedly lower the incidence of intraoperative acute vascular occlusion.
However, intimal hyperplasia at stent sites still leads to in-stent restenosis. Bare Metal Stents (BMS) have an in-stent restenosis rate of 20%-30% within 6 months after implantation. Drug-Eluting Stents (DES) are coated with biocompatible materials and therapeutic drugs on the metal framework, which inhibit smooth muscle proliferation and cut down the restenosis rate to below 10%. In contrast, DES may delay vascular endothelialization and raise the risk of in-stent thrombosis.
3. Rotational Atherectomy
This procedure employs an olive-shaped burr embedded with diamond particles. Based on the principle of selective ablation, it selectively removes fibrotic and calcified atherosclerotic plaques while preserving elastic tissues and normal coronary vessels. It is mainly indicated for severely stenotic lesions complicated with heavy calcification.
4. Intracoronary Thrombectomy
Negative-pressure aspiration catheters are used to extract thrombi inside coronary arteries, primarily applied to thrombotic lesions and saphenous vein graft lesions.
5. Cutting Balloon Angioplasty
Three to four micro-blades are longitudinally mounted on the balloon. When the balloon inflates, the blades incise hyperplastic tissues at stenotic sites into several parts, followed by full balloon dilation of the lesions. It is commonly used for in-stent restenosis and lesions dominated by fibrous hyperplasia.
6. Other Techniques
Including excimer laser angioplasty, intracoronary radiotherapy, etc., which are available for treating in-stent restenosis but have limited clinical application.
Related Medications
Aspirin: Administered 3-5 days preoperatively at a daily dose of 100-300mg; maintained at 100mg daily for long-term use after surgery.
Clopidogrel: 75mg daily for 4-6 days before surgery, or a loading dose of 300mg administered 6 hours preoperatively. The postoperative maintenance dose is 75mg daily, with a treatment course ranging from 1 month to 1 year determined by stent type and individual patient conditions. Novel anti-platelet agents such as prasugrel and ticagrelor are also under research and clinical promotion.
GP IIb/IIIa Receptor Antagonists: Intravenous preparations including abciximab, eptifibatide and tirofiban.
Heparin: Administered intravenously, mainly used during PCI procedures.
Low-Molecular-Weight Heparin: Subcutaneous injection, including enoxaparin, nadroparin, dalteparin, etc.
Factor Xa Inhibitors: Subcutaneous administration, represented by fondaparinux sodium.
Direct Thrombin Inhibitors: Intravenous use, such as bivalirudin and argatroban.