What is PTA in Interventional Cardiology?
PTA (Percutaneous Transluminal Angioplasty), also known as PTCA (Percutaneous Transluminal Coronary Angioplasty), is a balloon-based catheter technique used to dilate narrowed coronary arteries, and it represents the foundational procedure that evolved into the broader category of Percutaneous Coronary Intervention (PCI). 1
Historical Context and Terminology Evolution
PTCA specifically refers to balloon angioplasty alone, while the term PCI has replaced PTCA in modern guidelines to encompass the full spectrum of catheter-based coronary interventions. 1, 2 The ACC/AHA guidelines clarified this distinction, noting that PCI now includes:
- Balloon angioplasty (the original PTCA technique) 1
- Intracoronary stent implantation 1
- Rotational atherectomy 1
- Directional atherectomy 1
- Extraction atherectomy 1
- Laser angioplasty 1
- Other catheter devices for treating coronary atherosclerosis 1
Clinical Significance
PTCA represented a revolutionary shift from aggressive surgical revascularization to less invasive procedures. 3 The technique rapidly gained adoption and its utilization grew exponentially as technical advances pushed the boundaries of its indications. 3
Success Rates and Outcomes
- Primary success rates in experienced hands reach approximately 90-91% 4, 5
- Mortality for PTCA is less than 1% 4
- Emergency coronary surgery is required in less than 5% of patients 4
- Complications have decreased while success rates improved substantially with increasing operator experience 4, 6
Current Clinical Applications
Patient Selection Criteria
The indications for PTCA have expanded significantly from its original narrow application. 6 PTCA is now performed in:
- Patients with symptomatic coronary atherosclerosis 4
- Unstable angina pectoris (27% of current procedures) 4, 5
- Multivessel coronary disease in selected instances 4
- Multiple stenoses in single vessels 4
- Stenoses in coronary artery bypass grafts 4
- Recent total coronary occlusion 4
- Acute myocardial infarction (13% of current procedures) 5
- Stable angina (60% of current procedures) 5
Contraindications
PTCA is not indicated for:
- Long-standing complete coronary occlusions 4
- Diffuse atherosclerotic coronary stenoses without discrete stenotic segments 4
- Multiple sites of total occlusions 4
- "Skip" areas in vessels served by bridging collaterals 4
- Main left coronary stenoses (in most centers) 4
- Stenoses involving both sides of large-vessel bifurcations (in most centers) 4
Major Limitation: Restenosis
The "Achilles heel" of PTCA is restenosis, which develops in 25-35% of cases within 6 months. 7 This limitation drove the development of newer PCI technologies, particularly drug-eluting stents. 2
Factors Associated with Higher Restenosis Rates
- Proximal left anterior descending location 8
- Chronic total occlusions 8
- Branch vessel stenoses 8
- Long lesions 8
- Presence of thrombus 8
- Saphenous vein graft involvement (approximately 50% restenosis rate) 8
Common Pitfalls
Procedural Failures
The most common reasons for unsuccessful PTCA procedures include:
- Failure to cross the lesion with a wire or balloon (52% of failures) 5
- Abrupt closure of the dilated segment due to extensive local dissection (44% of failures) 5
- Failure to dilate the lesion (4% of failures) 5
Risk Assessment
The choice for or against PTCA should be made after careful assessment of the risk/benefit ratio of PTCA versus coronary bypass surgery. 4 Factors associated with increased mortality include female gender, age >65 years, congestive heart failure, unstable angina, left main coronary disease, three-vessel disease, and left ventricular ejection fraction <0.30. 1