Cardiac Catheterization

Introduction to Cardiac Catheterization

  • Cardiac catheterization, known as "cath," is a specialized study of the heart using a catheter, a thin, hollow, flexible tube.

  • Catheter is inserted into an artery or vein in the patient’s arm, neck, or groin.

  • A designated protocol and special equipment (needle, guidewire, sheath, stopcocks) are used for the procedure.

Cardiac Catheterization Procedures

Left Heart Catheterization (LHC)

  • **Procedure: **

    • Most commonly performed via the percutaneous femoral artery approach.

    • Uses a pigtail catheter to guide from femoral artery to:

      • Aorta

      • Coronary arteries

      • Aortic valve

      • Left ventricle

  • Indications:

    • Identifying the extent of coronary artery disease.

    • Evaluating left ventricular function.

    • Assessing valvular heart disease.

    • Evaluating myocardial disease (e.g., cardiomyopathy).

Right Heart Catheterization (RHC)

  • **Procedure: **

    • Most commonly performed via the femoral vein approach.

    • Uses Swan Ganz catheter, traveling from:

      • Femoral vein

      • Inferior vena cava

      • Right atrium

      • Tricuspid valve

      • Right ventricle

      • Pulmonic valve

      • Pulmonary artery

    • Can also involve a transseptal approach, passing from the right atrium to the left atrium.

Purpose of Cardiac Catheterization

  • Diagnosis and Evaluation

    • Identifying coronary artery disease and ischemic heart disease.

    • Assessing myocardial biopsy for heart transplant patients and myocarditis.

    • Evaluating left ventricular function and valvular heart disease.

    • Supporting noninvasive data for a more thorough analysis.

    • Determining the necessity for surgical correction of cardiac issues.

  • Imaging: Fluoroscopy provides real-time, immediate imaging, essential for proper catheter placement.

  • Filming: The study is filmed using cine angiography or digital imaging.

Treatment Modalities in the Cath Lab

Procedures During Cardiac Catheters

  • Right Heart Cath:

    • Collecting blood samples for oxygen saturation levels.

    • Determining shunt size through pulmonary and systemic flow evaluation.

    • Calculating cardiac output using various techniques (indicator dilution, thermal dilution).

    • Endomyocardial biopsy for transplant rejection and myocardial disease diagnosis.

    • Diagnosing pulmonary embolism via pulmonary angiography.

    • Measuring right heart pressures and acquiring left atrial pressure.

  • Left Heart Cath:

    • Provides vital information about left heart functions, coronary arteries, aortic valve, left ventricle.

    • Left ventricular angiogram evaluates left ventricular function.

    • Utilizes contrast agents to enhance visibility during X-ray imaging.

Coronary Arteries

  • Primary coronary arteries include:

    • AM: Acute Marginal Artery

    • CX: Left Circumflex Artery

    • LAD: Left Anterior Descending Artery

    • RCA: Right Coronary Artery

    • PA: Pulmonary Artery

    • PDA: Posterior Descending Artery

  • Each coronary artery branches further to form a capillary network within heart muscle.

Cardiac Pressures

  • Normal pressure measurements include:

    • AO (Aorta): Less than 120 mmHg / Less than 80 mmHg

    • LA (Left Atrium) / PCWP (Pulmonary Capillary Wedge Pressure): 2-12 mmHg

    • LV (Left Ventricle): Less than 120 mmHg / 3-12 mmHg

Interpretation of Pressure Tracings

  • Cath Lab vs. Echo Lab Tracings:

    • Cath lab measures direct chamber pressures.

    • Echo lab measures velocity to derive pressure using the Bernoulli equation.

    • Equation: Pressure gradient (PG) = 4 x (velocity^2)

  • Max PG provides the highest gradient between chambers during a cycle.

  • Mean PG represents average PG from all velocities.

Contraindications and Risks of Cardiac Catheterization

Contraindications

  • Active GI bleed.

  • Acute renal failure.

  • Evidence of acute stroke.

  • Allergic reactions to radiographic contrast.

  • Severe hypertension.

  • Ventricular arrhythmias.

  • Special precautions needed in some cases.

Risks

  • Bleeding at the entry site.

  • Risk of infection.

  • Injury to nerves or blood vessels.

  • Cardiac arrhythmias.

  • Cardiac tamponade from rapid fluid accumulation.

  • Low blood pressure.

  • Reactions to contrast agent.

  • Kidney damage or failure.

  • Potential for stroke or heart attack.

  • Death is rare, usually associated with critically ill patients.

Conclusion

  • Understand the importance of recognizing indications, risks, and procedures related to cardiac catheterization.