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Right Heart Catheterization

Ahmad Yanis

Pulmonary artery catheter (PAC): Multilumen catheter that sits in the right heart to provide invasive measurement of hemodynamic parameters

Indications for PAC placement

  • Diagnose undifferentiated shock

  • Severe cardiogenic shock

  • Diagnose pulmonary hypertension

  • Diagnose left -> right shunting

  • Diagnose valvular and pericardial disease

  • Titrating medications, specifically inotropes, pulmonary vasodilators, diuresis

Contraindications to PAC placement

  • Infection at the insertion site

  • RA/RV mass or thrombi

  • Tricuspid or pulmonic valve endocarditis

  • Mechanical tricuspid or pulmonic valves

  • Presence of RV assist device

Complications of PAC placement

  • Arrythmias: VT, RBBB, 3rd degree AV block if preexisting LBBB

  • Infection (endocarditis of the pulmonary valve)

  • Bleeding

  • Pulmonary embolism and pulmonary Infarct

  • Pneumothorax

  • Air embolism

  • Pulmonary artery perforation / rupture

  • Endocardial/valvular damage

PAC Pressure Tracings

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Definition Normal "Rule of 5s"

Interpretation

Central Venous Pressure

(CVP)

 Pressure in superior vena cava, often an indicator of volume status 0 - 5 mmHg Elevated CVP is indicative of cardiac dysfunction and/or fluid retention

Low CVP is indicative of volume depletion or decreased venous tone
Right Atrial Pressure (RAP) Surrogate for preload, should be same as CVP 0 - 5 mmHg Elevated with disruption in forward cardiac flow or increase in intravascular volume
Right Ventricle Pressure ( Right ventricular systolic and diastolic pressures; RVSP can be surrogate for PASP 25/5 mmHg Elevated with diseases that elevate PA pressure and pulmonic valve disorders. Severe RVP elevations are generally chronic while acute conditions typically have RVSP <40-50.
Pulmonary Artery Pressure (PAP) Measured as systolic, diastolic, and mean pressures. Diagnoses pHTN.

25/10 mmHg

Mean: 10 - 19 mmHg

 Elevated In acute conditions (PE, hypoxemia induced pulmonary vasoconstriction) or pHTN (mean PAP > 20 mm Hg)
Pulmonary Artery Wedge Pressure (PAWP or wedge) Pressure measured by wedging the PAC into a small pulmonary arterial branch; surrogate for left atrial pressures and LVEDP 10 mm Hg Increased with elevated LVEDP: systolic or diastolic heart failure, mitral and aortic valve disorders, hypervolemia, R to L shunts, tamponade, constrictive/restrictive cardiomyopathy
Thermodilution Cardiac Output & Index Amount of blood pumped in one min. CI is the cardiac output divided by body surface area (to standardize for body size)

CO: 3.4-15 L/min

CI: 2.8-4.2 L/min/m^2

Low CI: systolic/diastolic heart failure, severe valvular disorder (MR, AS), RV failure, pHTN, cardiogenic shock.

Elevated CI (high-output state): sepsis, anemia, thyrotoxicosis, A-V shunt

Mixed central venous oxyhemoglobin

saturation (SvO2)

 % of oxygen bound to Hgb in blood returning to the right side of the heart, reflects total body O2 extraction 65-70%

High SvO2 (> 65%) = decreased O2 demand or “high flow” states seen in distributive shock (sepsis)

Low SvO2 (< 50%) = decreased O2 delivery seen in cardiogenic or hypovolemic shock. In low SvO2 states, there is less O2 supply to same demand)

Calculating Hemodynamic Parameters from PAC Pressures

Definition Normal Values Interpretation
Fick CO and CI Calculated CO based on Oxygen consumption (VO2), Hbg, and O2 sats of arterial and venous blood

4-7 L/min

2.5-4 L/min/m2

 See "Cardiac Index" above.
Systemic Vascular Resistance (SVR) Measurement of afterload; helpful in delineating the etiology of shock as well as guiding afterload-reduction therapy in HFrEF 700-1200 dynes*s*cm-5

Elevated SVR is seen in hypovolemic, cardiogenic, and obstructive shock

Decreased SVR is seen in distributive shock (sepsis, anaphylaxis, neurogenic)
Transpulmonary gradient (TPG) Differentiates between pre- and post-capillary pulmonary hypertension. < 12 mmHg A TPG value greater than 12 mmHg indicates that a component of the pHTN is secondary to pulmonary vascular disease
Pulmonary Vascular Resistance (PVR) Gold standard in the estimation of the severity of pre-capillary pHTN

Reflects the pressure drop across the pulmonary system only and is independent of the LA, mitral valve and the LV

< 3 Wood Units

30-90 dynes*sec*cm5

Elevated PVR (>3 Wood units) suggests pre-capillary pHTN

Normal PVR seen in pulmonary venous hypertension (diastolic dysfunction)
Pulmonary artery pulsatility index (PAPi) Pulmonary pulse pressure relative to preload (RAP), Indicator of RV function > 0.9 PAPi < 0.9 predicts in-hospital mortality and/or need for RVAD in acute MI. Can be decreased in pure RV failure or biventricular failure
Cardiac Power Cardiac output relative to afterload, a measure of LV contractile reserve Normal > 1

CP< 0.6 strongly suggestive of LV failure

Found to be a strong independent hemodynamic correlate in pts with cardiogenic shock. Predictor of mortality in CCU