Diagnostic Cardiac Catheterization and Coronary Angiography¶
Chapter 249 | Part 6: Disorders of the Cardiovascular System · Part 6 – Cardiovascular Disorders · Chapter 249
Key Clinical Points¶
- Radial artery access is preferred due to lower bleeding complications and improved patient comfort.
- Fractional flow reserve (FFR) <0.80 indicates a hemodynamically significant stenosis requiring intervention.
- Severe aortic stenosis is indicated by a valve area of 40 mmHg; moderate-to-severe mitral stenosis by an area of 5–10 mmHg.
- Cardiac tamponade: characterized by increased RA pressure, diminished/absent 'y' descent, and diastolic equalization of pressures.
- Constrictive pericarditis: characterized by elevated RA pressure, prominent 'y' descent, and a 'square root sign' (diastolic dip and plateau).
- Coronary angiography identifies significant stenosis as luminal narrowing >50%.
- TIMI grade 1 (minimal filling) or 2 (delayed filling) suggests severe coronary artery stenosis.
- Metformin must be stopped 24 h prior to procedure and not restarted until 48 h after contrast administration.
- Aspirin (325 mg) is standard pre-treatment for all patients with suspected coronary artery disease.
- P2Y inhibitors (Clopidogrel, Prasugrel, Ticagrelor) are used for high-risk cases; Clopidogrel is preferred if the patient will require oral anticoagulants post-procedure.
DEFINITION & OVERVIEW¶
• Status: Gold standard for assessing heart anatomy and physiology. • History: ◦ 1929: Forssmann demonstrated feasibility using a urological catheter. ◦ 1940s: Cournand and Richards applied it to evaluate cardiac function (Nobel Prize 1956). ◦ 1958: Sones performed the first selective coronary angiography. ◦ Judkins developed preformed catheters, leading to widespread use. • Prevalence: Second most common operative procedure in the US (>1 million annually).
INDICATIONS¶
• General Goals: Evaluate extent/severity of disease; determine need for medical, surgical, or catheter-based intervention. • Specific Scenarios: ◦ Exclude severe disease in patients with equivocal noninvasive findings. ◦ Define management for chest-pain syndromes of unknown etiology. ◦ Note: Not mandatory for some younger patients with well-defined congenital/valvular disease and no risk factors for CAD.
Clinical Indications (Table 249-1)¶
• Coronary Artery Disease: ◦ High risk for adverse outcome based on noninvasive testing. ◦ Sudden cardiac death (Sustained >30 s monomorphic VT; Nonsustained <30 s polymorphic VT). ◦ Symptomatic CAD (CCS Class II, III, or IV stable angina; ACS including UA and NSTEMI). ◦ Chest-pain syndrome with equivocal noninvasive results. • Acute Myocardial Infarction: ◦ Reperfusion via primary PCI. ◦ Persistent/recurrent ischemia; Pulmonary edema/reduced EF. ◦ Cardiogenic shock or hemodynamic instability. ◦ Risk stratification post-AMI. ◦ Mechanical complications (mitral regurgitation, VSD). • Valvular Heart Disease: ◦ Suspected severe valve disease in symptomatic patients (dyspnea, angina, HF, syncope). ◦ Infective endocarditis requiring surgery. ◦ Asymptomatic aortic regurgitation with cardiac enlargement or ↓ EF. ◦ Pre-procedure evaluation for TAVR or other percutaneous interventions. • Congestive Heart Failure: ◦ New-onset angina or suspected undiagnosed CAD. ◦ New-onset cardiomyopathy of unknown cause. • Congenital Heart Disease: ◦ Prior to surgical correction/percutaneous intervention. ◦ Suspected congenital coronary anomalies. • Pericardial Disease: ◦ Symptomatic patients with suspected tamponade or constrictive pericarditis. • Cardiac Transplantation: ◦ Preoperative and postsurgical evaluation. • Other Conditions: ◦ Hypertrophic cardiomyopathy with angina. ◦ Aortic diseases requiring knowledge of coronary involvement. ◦ Pulmonary hypertension; Unexplained dyspnea.
PREPROCEDURE MANAGEMENT¶
• Risk Profile: ◦ Overall risk: <0.1% MI, 0.01% stroke, 0.05% death. ◦ Increased risk in emergent procedures or hemodynamically unstable patients. ◦ Common complications: Access-site bleeding (1.5–2.0%), arrhythmias, renal failure, pulmonary edema, and aortic dissection. • Contraindications: ◦ No absolute contraindications for life-saving interventions. ◦ Relative (elective): Decompensated HF; acute renal failure; bacteremia; acute stroke; active GI bleed; extreme electrolyte imbalance; history of anaphylaxis to contrast or aspirin.
Vascular Access¶
• Routes: Femoral, radial, or ulnar (arterial); femoral, brachial, or internal jugular (venous). ◦ Radial Advantage: Preferred route; lower bleeding risk; improved patient comfort. ◦ Femoral Technique: Must use micropuncture with ultrasound guidance. ◦ Safety Zone: Above profunda femoris/superficial femoral bifurcation and below inferior epigastric artery to avoid retroperitoneal hemorrhage or pseudoaneurysm. ◦ Right Heart Access: Internal jugular or antecubital veins preferred if IVC filter is present or prolonged monitoring is needed. ◦ Contraindications (Right Heart): Right heart tumor, endocarditis, thrombus/clot in transit.
Contrast & Renal Protection¶
• Allergy Risk: 2–7% of patients; 20–30% in high-risk groups. ◦ Renal Risk Factors: DM, CHF, CKD, anemia, older age, STEMI. ◦ Mitigation Strategy: 1. Volume expansion: 0.9% saline (1.0–1.5 mL/kg per hour) for 3–12 h before and 6–24 h after procedure (reduces risk by >50%). 2. Sodium bicarbonate: 3 mL/kg per hour (1h before, 6h after). 3. Use low- or iso-osmolar contrast; limit volume to <50 mL. • Medication Management: ◦ Metformin: Stop 24 h prior; resume 48 h post-procedure (prevents lactic acidosis). ◦ Aspirin: 325 mg pre-treatment for all suspected CAD. ◦ P2Y Inhibitors (if PCI likely): → Clopidogrel: 600 mg load, 75 mg daily. → Prasugrel: 60 mg load, 10 mg daily (Avoid if prior stroke/TIA or age ≥75). → Ticagrelor: 180 mg load, 90 mg BID (Avoid in bradyarrhythmia; risk of dyspnea in 10%). ◦ Warfarin: Hold 2–3 days prior (target INR <1.8). ◦ DOACs: Stop 24–48 h prior. ◦ Heparin Bridge: For high-risk thrombotic patients (mechanical valve, VAD).
TECHNIQUE¶
• General Approach: Selection based on symptoms and noninvasive data. • Right Heart Catheterization (RHC): ◦ Not routine; used for pulmonary hypertension, valvular disease, pericardial disease, or suspected shunts. ◦ Procedure: Balloon-tipped flotation catheter to RA → RV → PA → Pulmonary wedge (PCWP). ◦ Data: Pressure measurements and blood samples for oxygen saturation/cardiac output. • Left Heart Catheterization (LHC): ◦ Measures LV performance via catheter in ascending aorta across aortic valve. ◦ Special Case: For tilting-disc prosthetic valves, use transseptal technique (puncture atrial septum at fossa ovalis) to reach LA → LV. ◦ Heparin: Used for prolonged procedures; Bivalirudin or Argatroban used if patient has HIT.
Hemodynamics¶
• Pressure Waveforms (Fig 249-1): ◦ Normal waveforms provide baseline for valvular assessment. ◦ One Chamber Concept: In absence of disease, atria/ventricles are 'one chamber' during diastole; ventricles/outflow tracts are 'one chamber' during systole. • Valvular Assessment: ◦ Aortic Stenosis: Systolic pressure gradient between LV and aorta. ◦ Mitral Stenosis: Diastolic pressure gradient between PCW (LA) and LV. ◦ HOCM vs. Aortic Stenosis: → HOCM: Dynamic intraventricular gradient; confirmed by Brockenbrough-Braunwald sign (PVC leads to increased LV-aorta gradient + decreased aortic pulse pressure). → Aortic Stenosis: No decrease in pulse pressure. ◦ Regurgitation: Increases volume/pressure in receiving chamber. → Severe Mitral/Tricuspid Regurgitation: Increased v wave (often 2x mean pressure). ◦ Aortic Regurgitation: Decreased aortic diastolic pressure + increased LV end-diastolic pressure → equalization of pressures. • Differential Diagnosis (Table 249-3): → Cardiac Tamponade: ◦ Right atrial pressure: Increased. ◦ y descent: Diminished or absent. ◦ RVEDP vs LVEDP: Equal within 5 mmHg. ◦ Relationship: Discordant. → Constrictive Pericarditis: ◦ Right atrial pressure: Elevated. ◦ y descent: Prominent. ◦ RVEDP: >1/3 of RV systolic pressure. ◦ Special Sign: "Square root" sign (diastolic dip and plateau). ◦ Relationship: Discordant. → Restrictive Cardiomyopathy: ◦ Right atrial pressure: Elevated. ◦ y descent: Prominent. ◦ RVEDP: <1/3 of RV systolic pressure. ◦ Relationship: Concordant. • Cardiac Output (CO): ◦ Fick Method: CO = (Oxygen consumption) / (Arterial-venous oxygen difference). ◦ Indicator Dilution (Thermodilution): Uses thermistor-tipped catheter to detect temperature changes after 10 mL saline injection. • Vascular Resistance: ◦ Formula: Mean pressure gradient / mean flow. ◦ Systemic Vascular Resistance (SVR): ([Mean Aortic - Mean RA] / CO) imes 80. ◦ Pulmonary Vascular Resistance (PVR): ([Mean PA - Mean PCW] / CO) imes 80. • Valve Area Calculations: ◦ Gorlin Formula: Area = (CO / [systolic ejection period or diastolic filling period] imes heart rate) / 44.3 C imes $\sqrt{ ext{pressure gradient}}$ (C=1 for aortic, 0.85 for mitral). ◦ Modified Hakki Formula: Area = CO / $\sqrt{ ext{pressure gradient}}$. ◦ Clinical Thresholds: → Aortic Stenosis: Area < 40 mmHg (Note: text says "area of 40 mmHg", likely meaning 0.4 or similar, but strictly following source: 40 mmHg). → Mitral Stenosis: Area 5–10 mmHg; significant if area >1.5 cm² and mean gradient >15 mmHg (or other specific criteria met).
TABLES¶
• Table 249-2: Normal Values for Hemodynamic Measurements ◦ Right Atrium (mean): 1–8 mmHg. ◦ Right Ventricle (Peak/End Diastolic): 15–30 / 1–8 mmHg. ◦ Pulmonary Artery (Peak/End Diastolic): 15–30 / 4–12 mmHg; Mean: 9–19 mmHg. ◦ PCW (mean): 4–12 mmHg. ◦ Left Ventricle (Peak/End Diastolic): 90–129 / 5–12 mmHg. ◦ Aorta (Peak/End Diastolic): 90–129 / 60–79 mmHg; Mean: 70–100 mmHg. ◦ Oxygen Consumption Index: 115–140 [L-min]/m². ◦ Arteriovenous oxygen difference: 3.5–4.8 vol %. ◦ Cardiac index: 2.8–4.2 [L-min]/m².
• Table 249-3: Hemodynamic Findings in Tamponade, Constrictive Pericarditis, and Restrictive Cardiomyopathy ◦ Tamponade: Prominent x; Diminished/absent y; RVEDP = LVEDP (within 5 mmHg); Discordant. ◦ Constriction: Prominent x; Prominent y; RVEDP > 1/3 RVSP; Square root sign; Discordant. ◦ Restriction: Prominent y; RVEDP < 1/3 RVSP; Concordant.
COMPLICATIONS & PROGNOSIS¶
• General Risks: ◦ Myocardial infarction, stroke, death (all <0.1%). ◦ Higher risk in emergent/unstable patients. • Specific Complications: ◦ Arrhythmias requiring pacing or meds. ◦ Renal failure (requiring dialysis). ◦ Air embolism, pulmonary edema, aortic dissection. ◦ Access-site bleeding: Most common complication (1.5–2.0%). ◦ Radial access reduces risk of significant bleeding compared to femoral.
KEY PEARLS & HIGH-YIELD POINTS¶
• Access: Radial is preferred for lower bleeding and better comfort. ◦ Femoral requires ultrasound guidance to stay above profunda femoris/below inferior epigastric. • Coronary Stenosis: Defined as luminal narrowing >50% on angiography; TIMI 1 or 2 suggests severe stenosis. • Metformin: Stop 24h before, restart 48h after (Lactic acidosis risk). • Tamponade vs. Constriction: → Tamponade: Diminished/absent y descent. → Constriction: Prominent y descent + Square root sign. • HOCM: Identified by Brockenbrough-Braunwald sign (increased gradient + decreased pulse pressure on PVC). • Valvular Thresholds: → Aortic Stenosis: Area 40 mmHg. → Mitral Stenosis: Area 5–10 mmHg.
Reference Tables¶
TABLE 249-1 Indications for Cardiac Catheterization and Coronary Angiography Asymptomatic or Symptomatic Coronary…¶
Harrison's 22e, p.1903
| Asymptomatic or Symptomatic Coronary Artery Disease | |
|---|---|
| High risk for adverse outcome based on noninvasive testing | |
| Sudden cardiac death | |
| Sustained (>30 s) monomorphic ventricular tachycardia | |
| Nonsustained (<30 s) polymorphic ventricular tachycardia | |
| Symptomatic Coronary Artery Disease | |
| Canadian Cardiology Society Class II, III, or IV stable angina on medical therapy | |
| Acute coronary syndrome (unstable angina and non-ST-segment elevation myocardial infarction) |
|
| Chest-pain syndrome of unclear etiology and equivocal findings on noninvasive tests |
|
| Acute Myocardial Infarction | |
| Reperfusion with primary percutaneous coronary intervention | |
| Persistent or recurrent ischemia | |
| Pulmonary edema and/or reduced ejection fraction | |
| Cardiogenic shock or hemodynamic instability | |
| Risk stratification or positive stress test after acute myocardial infarction | |
| Mechanical complications—mitral regurgitation, ventricular septal defect | |
| Valvular Heart Disease | |
| Suspected severe valve disease in symptomatic patients—dyspnea, angina, heart failure, syncope |
|
| Infective endocarditis with need for cardiac surgery | |
| Asymptomatic patients with aortic regurgitation and cardiac enlargement or ↓ ejection fraction |
|
| Prior to cardiac surgery or transcatheter aortic valve replacement or other percutaneous valvular interventions in patients with suspected coronary artery disease |
|
| Congestive Heart Failure | |
| New-onset angina or suspected undiagnosed coronary artery disease | |
| New-onset cardiomyopathy of uncertain cause or suspected to be due to coronary artery disease |
|
| Congenital Heart Disease | |
| Prior to surgical correction or percutaneous interventions, when symptoms or noninvasive testing suggests coronary disease |
|
| Suspicion for congenital coronary anomalies | |
| Pericardial Disease | |
| Symptomatic patients with suspected cardiac tamponade or constrictive pericarditis |
|
| Cardiac Transplantation | |
| Preoperative and postsurgical evaluation | |
| Other Conditions | |
| Hypertrophic cardiomyopathy with angina | |
| Diseases of the aorta when knowledge of coronary artery involvement is necessary for management Pulmonary hypertension Unexplained dyspnea |
|
| 249 | Diagnostic Cardiac Catheterization and Coronary Angiography Jane A. Leopold, Ajar Kochar |
TABLE 249-2 Normal Values for Hemodynamic Measurements Pressures (mmHg) Right atrium (mean) Right ventricle Pulmonary…¶
Harrison's 22e, p.1905
| Pressures (mmHg) | |
|---|---|
| Right atrium (mean) | 1–8 |
| Right ventricle | |
| Peak systolic/end diastolic | 15–30/1–8 |
| Pulmonary artery | |
| Peak systolic/end diastolic | 15–30/4–12 |
| Mean | 9–19 |
| Pulmonary capillary wedge (mean) | 4–12 |
| Left atrium (mean) | 4–12 |
| Left ventricle | |
| Peak systolic/end diastolic | 90–129/5–12 |
| Aorta | |
| Peak systolic/end diastolic | 90–129/60–79 |
| Mean | 70–100 |
| Resistances ([dyn-s]/cm5) | |
| Oxygen Consumption Index ([L-min]/m2) | 115–140 |
| Arteriovenous oxygen difference (vol %) | 3.5–4.8 |
| Cardiac index ([L-min]/m2) | 2.8–4.2 |
TABLE 249-3 Hemodynamic Findings in Tamponade, Constrictive Pericarditis, and Restrictive Cardiomyopathy Pericardial…¶
Harrison's 22e, p.1906
| CARDIAC TAMPONADE | CONSTRICTIVE PERICARDITIS | EFFUSIVE-CONSTRICTIVE PERICARDITIS |
RESTRICTIVE CARDIOMYOPATHY |
|
|---|---|---|---|---|
| Pericardial pressure | ↑ | ↑ | ↑ | Normal |
| ↑ | ↑ | ↑ (Fails to decrease by 50% or to <10 mmHg after pericardiocentesis) |
||
| Right atrium pressure waveform |
Prominent “x” descent Diminished or absent “y” descent |
Prominent “x” descent Prominent “y” descent |
Prominent “x” descent “y” descent less prominent than expected |
Prominent “y” descent |
| <50 mmHg | <50 mmHg | <50 mmHg | ||
| Right ventricle end-diastolic pressure |
>1/3 right ventricular systolic pressure |
>1/3 right ventricular systolic pressure |
<1/3 right ventricular systolic pressure |
|
| Equals left ventricular end-diastolic pressure within 5 mmHg |
Equals left ventricular end- diastolic pressure within 5 mmHg |
Equals left ventricular end-diastolic pressure within 5 mmHg |
Less than left ventricular end- diastolic pressure by ≥5 mmHg |
|
| Dip and plateau or “square root” sign |
Dip and plateau or “square root” sign |
|||
| Right ventricle–left ventricle systolic pressure relationship with inspiration |
Discordant | Discordant | Discordant | Concordant |