What are the key concepts in interventional cardiology that I need to know for boards?

Interventional Cardiology Board Masterclass

Core Cognitive Knowledge Base

You must master cardiac hemodynamics, coronary anatomy, and the pathophysiology of acute coronary syndromes to succeed on boards. 1

Fundamental Hemodynamics

• Understand pressure-volume relationships, cardiac output measurement (Fick principle, thermodilution), and resistance calculations 1
• Differentiate constrictive pericarditis from restrictive cardiomyopathy hemodynamically: Look for ventricular interdependence, respiratory variation in ventricular filling, and equalization of diastolic pressures in constriction 1
• Recognize tamponade physiology: Equalization of diastolic pressures across all chambers, pulsus paradoxus >10mmHg, and blunted y-descent on right atrial tracing 1
• Interpret valvular lesions: Calculate valve areas using Gorlin formula, assess gradients, and understand pressure half-time for mitral stenosis 1

Coronary Anatomy & Physiology

• Master all standard angiographic views: RAO/LAO cranial/caudal angulations for each coronary segment 1
• Understand fractional flow reserve (FFR) and non-hyperemic pressure ratios: FFR ≤0.80 indicates hemodynamically significant stenosis; understand limitations with tandem lesions, ostial disease, and microvascular dysfunction 1
• Know Doppler flow assessment: Coronary flow reserve <2.0 suggests microvascular dysfunction or significant epicardial disease 1

Clinical Syndromes: Recognition & Management

Acute Coronary Syndromes

Rapidly identify STEMI and initiate reperfusion within 90 minutes door-to-balloon time for optimal outcomes. 1

• STEMI management: Primary PCI is preferred over fibrinolysis when available within appropriate timeframes; understand door-to-balloon time quality metrics 1, 2
• NSTEMI/Unstable Angina: Risk stratify using GRACE or TIMI scores to determine timing of invasive strategy (immediate, early <24h, or delayed) 1, 2
• Myocardial infarction with non-obstructive coronary arteries (MINOCA): Consider spontaneous coronary artery dissection, coronary vasospasm, thromboembolism, or microvascular dysfunction 1

Cardiogenic Shock

Implement early invasive hemodynamic monitoring with pulmonary artery catheterization to guide therapy in cardiogenic shock. 2

• Diagnostic criteria: Hypotension (SBP <90mmHg), cool extremities, acidosis (lactate >2mmol/L), elevated pulmonary capillary wedge pressure (>15mmHg) 1, 2
• Calculate cardiac power output: (MAP × cardiac output)/451; <0.6 watts predicts poor outcomes 2
• Pulmonary arterial pulsatility index: (PA systolic - PA diastolic)/PCWP; <1.0 suggests right ventricular failure and need for mechanical support 2
• Mechanical circulatory support indications: Consider IABP, Impella, or VA-ECMO based on shock severity and hemodynamic phenotype 2

Intracoronary Imaging & Physiology

Intravascular Ultrasound (IVUS)

Use IVUS to optimize stent sizing, identify plaque characteristics, and assess stent deployment. 1

• Recognize plaque types: Soft (echolucent), fibrous (intermediate echogenicity), calcified (bright with acoustic shadowing) 1
• Identify complications: Dissection (intimal flap), thrombus (mobile, low echogenicity), stent malapposition (separation from vessel wall), underexpansion 1
• Optimal stent deployment criteria: Minimum stent area >5.0mm² for left main, >5.5mm² for proximal LAD, complete apposition, no edge dissection 1
• Measure accurately: Vessel diameter, lesion length, reference segment dimensions for appropriate device sizing 1

Optical Coherence Tomography (OCT)

• Higher resolution than IVUS (10-20μm vs 100-150μm): Superior for detecting thin-cap fibroatheroma, thrombus, and stent strut coverage 1
• Limitations: Requires blood clearance with contrast injection; limited penetration depth; avoid in ostial left main disease 1
• Identify mechanisms of stent failure: Underexpansion, malapposition, neoatherosclerosis, or uncovered struts in late thrombosis 1

Physiological Assessment

• FFR cutoff ≤0.80: Indicates ischemia-producing stenosis warranting revascularization 1
• Instantaneous wave-free ratio (iFR) ≤0.89: Non-hyperemic alternative to FFR 1
• Post-PCI physiology: FFR >0.90 or iFR >0.95 indicates optimal result and predicts better outcomes 1
• Recognize drift: >0.03 difference between initial and final pressure wire equalization suggests technical error 1

Devices & Equipment Mastery

Guide Catheters

• Judkins curves: JL4 for most left coronaries, JR4 for right; upsize for larger aortic roots 1
• Amplatz curves: AL1/AL2 for horizontal left main or difficult left engagement; AR1/AR2 for shepherd's crook RCA 1
• Guide extensions: Use for extra support in tortuous vessels or distal lesions 1

Guidewires

• Workhorse wires: Moderate support, tip load 1-3g (e.g., BMW, Runthrough) for most lesions 1
• Stiff wires: Higher tip load for calcified or tortuous vessels 1
• Polymer-jacketed wires: Low friction for crossing tight lesions 1
• CTO wires: Tapered or stiff-tip wires with penetration force for chronic total occlusions 1

Atherectomy Devices

Use atherectomy for heavily calcified lesions that cannot be adequately prepared with balloon angioplasty alone. 1

• Rotational atherectomy: High-speed (140,000-190,000 rpm) diamond-coated burr for concentric calcification; start with burr-to-artery ratio 0.5-0.6 1
• Orbital atherectomy: Eccentric sanding motion for both concentric and eccentric calcium 1
• Laser atherectomy: Pulsed UV light for uncrossable lesions or in-stent restenosis 1
• Intravascular lithotripsy: Sonic pressure waves to fracture calcium; useful for both superficial and deep calcium 1

Stent Selection

• Drug-eluting stents (DES): Standard for most lesions; newer-generation DES (everolimus, zotarolimus) have lower thrombosis rates than first-generation 1
• Sizing: Use 1:1 stent-to-vessel ratio based on distal reference segment; avoid oversizing >0.5mm 1
• Post-dilation: Use non-compliant balloon at high pressure (≥18 atm) to optimize expansion 1

Procedural Complications: Recognition & Management

Coronary Perforation

Immediately reverse anticoagulation and perform prolonged balloon inflation at low pressure (2-4 atm) for 5-10 minutes. 1

• Ellis classification: Type I (extraluminal crater), Type II (pericardial/myocardial blush), Type III (frank perforation with contrast streaming), cavity spilling 1
• Management algorithm: Balloon tamponade → covered stent if persistent → coil embolization if distal → pericardiocentesis if tamponade develops 1

No-Reflow Phenomenon

• Definition: TIMI flow <3 without dissection, thrombus, or spasm 1
• Treatment: Intracoronary vasodilators (adenosine 60-180μg, verapamil 100-200μg, nicardipine 200μg, nitroprusside 50-200μg) 1
• Prevention: Use distal protection devices in saphenous vein graft interventions 1

Coronary Dissection

• Classify severity: NHLBI types A-F; types C-F require treatment 1
• Management: Stent across dissection entry and exit; extend coverage 5mm beyond visible dissection 1

Vascular Access Complications

• Retroperitoneal hemorrhage: Suspect with unexplained hypotension, back/flank pain, or drop in hemoglobin after femoral access; diagnose with CT; requires transfusion and possible surgical/endovascular intervention 1
• Pseudoaneurysm: Pulsatile groin mass with bruit; diagnose with ultrasound; treat with ultrasound-guided compression or thrombin injection if >2cm 1

Pharmacology: Critical Medications

Antiplatelet Agents

• Aspirin: 162-325mg loading, 81mg maintenance indefinitely 1
• P2Y12 inhibitors: Clopidogrel 600mg load (300mg if >75 years), ticagrelor 180mg load, or prasugrel 60mg load (avoid if >75 years, <60kg, or prior stroke) 1
• Glycoprotein IIb/IIIa inhibitors: Eptifibatide (180μg/kg bolus, 2μg/kg/min infusion) or abciximab for high thrombus burden or bailout 1, 3

Anticoagulants

• Unfractionated heparin: 70-100 units/kg bolus (50-70 units/kg if using GP IIb/IIIa); target ACT 250-350 seconds (200-250 with GP IIb/IIIa) 1
• Bivalirudin: 0.75mg/kg bolus, 1.75mg/kg/hr infusion; reduces bleeding compared to heparin plus GP IIb/IIIa 1

Contrast Nephropathy Prevention

• High-risk patients: eGFR <60, diabetes, heart failure, age >75 1
• Prevention: IV isotonic saline 1mL/kg/hr for 12 hours pre- and post-procedure; minimize contrast volume (<3× eGFR or <350mL total) 1

Radiation Safety

Understand ALARA principles (As Low As Reasonably Achievable) and minimize fluoroscopy time. 1

• Reduce scatter radiation: Maximize distance from X-ray source, use lead shielding, minimize beam-on time 1
• Optimize imaging: Use collimation, avoid steep angulations, use low frame rates (7.5 fps for acquisition, 3.75 fps for positioning) 1
• Monitor exposure: Track cumulative air kerma; >5 Gy requires follow-up for skin injury 1

Vascular Access Techniques

Femoral Access

• Anatomic landmark: 1-2cm below inguinal ligament, above femoral bifurcation 1
• Micropuncture technique: Use 21-gauge needle with 0.018" wire to minimize complications 1
• Closure devices: Consider for anticoagulated patients or early ambulation; contraindicated if puncture above inguinal ligament or significant peripheral arterial disease 1

Radial Access

• Allen test: Ensure ulnar collateral flow before radial puncture 1
• Anticoagulation: Heparin 5000 units or bivalirudin to prevent radial artery occlusion 1
• Advantages: Lower bleeding risk, earlier ambulation, preferred in ACS and obese patients 1

Special Populations & Scenarios

Left Main Disease

• SYNTAX score: Calculate to guide revascularization strategy (PCI vs CABG); low score (≤22) favors PCI, high score (≥33) favors CABG 1
• Intravascular imaging mandatory: Use IVUS or OCT to optimize stent sizing and deployment 1
• Two-stent techniques: Provisional stenting preferred; use crush, culotte, or TAP technique for true bifurcations 1

Chronic Total Occlusions (CTO)

• J-CTO score: Predicts procedural difficulty based on blunt stump, calcification, tortuosity, occlusion length >20mm, and prior attempt 1
• Antegrade vs retrograde approach: Antegrade wire escalation first; consider retrograde if septal collaterals present 1

Post-CABG Patients

• Saphenous vein grafts: High risk of distal embolization; use embolic protection devices and avoid aggressive manipulation 1
• Internal mammary arteries: Require specific guide catheters (IMA or multipurpose); handle gently to avoid spasm 1