What are the risks of percutaneous coronary intervention (PCI) and how should they be managed?

Risks of Percutaneous Coronary Intervention

PCI carries well-defined procedural risks including death (<1.2%), myocardial infarction (2-2.5% for Q-wave MI), coronary perforation (0.2%), bleeding complications, contrast-induced kidney injury, and vascular access site complications, with risk magnitude varying by patient characteristics, lesion complexity, and procedural technique. 1

Major Procedural Complications

Death and Myocardial Infarction

• Mortality risk is approximately 0.5% for standard PCI procedures 1
• Q-wave MI occurs in <2.5% of cases, with non-Q-wave MI rates potentially higher, particularly in saphenous vein graft interventions 1
• Clinical success rates decline with less appropriate indications: 92.8% for Class I indications versus 85.5% for Class III indications 1
• Unprotected left main PCI in surgically ineligible patients carries significantly elevated mortality (20% versus 5.3% in surgical candidates) 2

Coronary Perforation

• Occurs in approximately 0.2% of procedures, with higher rates when using ablative technologies (rotational atherectomy, directional atherectomy, excimer laser) 1, 3
• Risk increases in elderly patients, women, and during chronic total occlusion (CTO) interventions 1
• 20% of perforations are guidewire-related; most result from device oversizing or ablative technology 1
• Ellis Type III perforations (frank extravasation ≥1mm) require immediate covered stent deployment 3
• Distal vessel perforations require coil embolization as primary treatment 3

Bleeding Complications

• Periprocedural bleeding is now recognized as independently associated with subsequent mortality 1
• Risk factors include advanced age, low body mass index, chronic kidney disease, baseline anemia, degree of antiplatelet/thrombin inhibition, vascular access site, and sheath size 1
• Radial access reduces bleeding risk compared to femoral access, though radial artery spasm may complicate the procedure 1
• Access site complications include pseudoaneurysm (0.01%), compartment syndrome, and local hematomas 1

Contrast-Induced Acute Kidney Injury

• Incidence depends on baseline risk factors: advanced age, pre-existing chronic kidney disease (CrCl <60 mL/min), congestive heart failure, diabetes, and contrast volume administered 1
• Adequate preparatory hydration is mandatory for all patients 1
• Minimize contrast volume in patients with CKD 1
• N-acetyl-L-cysteine is NOT beneficial for prevention (Class III: No Benefit) 1

High-Risk Scenarios Requiring Special Consideration

Hemodynamically Compromised Patients

• Patients with cardiogenic shock, extremely depressed left ventricular function, or borderline hemodynamics benefit from intra-aortic balloon pump insertion prior to coronary instrumentation 1
• Cardiopulmonary support should be reserved for extreme hemodynamic compromise 1
• Obtain contralateral femoral access before starting high-risk procedures to facilitate rapid balloon pump insertion if needed 1

Multi-vessel Disease in STEMI

• PCI of non-infarct arteries at the time of primary PCI in hemodynamically stable STEMI patients is harmful (Class III: Harm) 1
• Exception: patients in cardiogenic shock may benefit from PCI of severe stenosis in large non-infarct arteries during the primary procedure 1

Patients on Oral Anticoagulation

• Triple therapy (oral anticoagulation plus dual antiplatelet therapy) significantly increases bleeding risk 1
• Continuation of antiplatelet therapy beyond 1 year with oral anticoagulation increases bleeding without additional ischemic protection 1
• Proton pump inhibitor use should be considered to reduce gastrointestinal bleeding, preferably non-CYP2C19-interfering agents (pantoprazole, dexlansoprazole) 1

Post-Procedural Complications and Warning Signs

No-Reflow Phenomenon

• Suboptimal myocardial perfusion despite restored epicardial flow, associated with reduced survival 1
• Results from inflammation, endothelial injury, edema, atheroembolization, vasospasm, and reperfusion injury 1
• Manual thrombus aspiration may improve tissue perfusion and ST resolution 1

Post-PCI Leukocytosis

• Recurrent chest pain with ECG changes plus leukocytosis warrants investigation for complications 4
• Fever or hemodynamic instability with leukocytosis requires evaluation for infection or other complications 4
• White blood cell elevation beyond 4-5 days without downward trend requires further investigation 4
• New cardiac biomarker elevation suggesting peri-procedural MI with leukocytosis needs evaluation 4

Critical Procedural Pitfalls

Ad Hoc PCI Considerations

• Ad hoc PCI increases procedural contrast use and should be avoided when excessive contrast administration is anticipated 1
• Higher complication rates in multivessel disease, women, patients >65 years, and multilesion interventions 1
• Should only be performed in well-informed patients with single-vessel disease without high-risk morphologic features 1

Equipment and Preparation Requirements

• For high-risk procedures (CTO, heavily calcified lesions), covered stents and coils must be immediately available with operator training in emergency deployment 3
• Defibrillators and hemodynamic support equipment require routine assessment and readiness 1