Pulmonary Artery Catheter

Indications for Right Heart Catheterisation (RHC):

Class 1A = Assessment for cardiac transplantation

Class 1c = Diagnose PH

Class 2a = Determine vasoreactivity responsiveness

ESC / ERS recommend RHC as the gold standard test for diagnosis and management of PAH

Morbidity = 1.1%

Mortality = 0.055% [1]

Background

1. Precapillary PH = mPAP > 25mmHg and PCWP < 15mmHg
2. Post capillary PH = mPAP > 25mmHg and PCWP > 15mmHg. This is also termed “PH due to left heart disease e.g. mitral pathology or chronically low LVEF%)

Measured Values

RV - End Diastolic Pressure

Derived Values

Transpulmonary Gradient (TPG)

TPG = mPAP - PCWP

Normal = < 12-15mmHg

Elevated = > 15mmHg

• Describes the relationship between PCWP and mPAP
• Normally PCWP should be <15mmHg (and LVEDP < 18mmHg)
• “Filling pressures” begin to rise as heart failure ensues with PCWP and LVEDP rising
• This results in increased PCWP and “in-proportion” increases in mPAP. This condition is sometimes referred to as “post-capillary PH” or WHO - Group 2 PH (Due to “left sided” heart disease)
• For patients with elevated mPAP who have normal PCWP these increases in mPAP are said to be “out of proportion” or “precapillary” in nature.
• Elevated TPG suggesting “pre-capillary” PH may be amenable to therapies that lower PVR such as Sildenafil, Epoprostenol or Bosentan.
• High TPG > 15mmHg is associated with increased in-hospital mortality and LOS after heart transplantation.

Diastolic Pressure Gradient (DPG)

A “Shunt run”

• Describes taking blood gases sequentially from the SVC, IVC, RA, RV and PA
• Increases in SvO2 at each site suggest a shunt
• The specific site of the “step-up” can be used to confirm the shunt location

PA - Pulsatility Index “PAPi”

Composite measure of RV function

1. Mean RAP
2. PA-pulse pressure
3. Cardiac index

Equation PAPi =

LOW values confer worse outcome in

1. Group 1 PAH - 5 year outcomes shown in graph below of Q1 vs Q2-4
2. Post-inferior RCA infarct
3. With LVAD / Impella

References:

A systematic review and physiology of pulmonary artery pulsatility index in left ventricular assist device therapy

Durable left ventricular assist devices (LVAD) have become an established therapy in patients with end-stage heart failure.

academic.oup.com

https://onlinejcf.com/article/S1071-9164(16)30147-6/fulltext#:~:text=Results: The median age of,risk stratification in these patients.

RV Stroke Work Index (RVSWI)

Equation:

RVSWI = [mPAP-mRAP] x SVI x 0.0136

Note: SVI = Cardiac index x1000 / Heart rate

References

Values < 19.7 = worse outcomes >19.7 better outcomes in CTEPH patients

References

1. Hoeper MM, Lee SH, Voswinckel R, et al. Complications of right heart catheterization procedures in patients with pulmonary hypertension in experienced centers. J Am Coll Cardiol. 2006 Dec 19; 48(12): 2546–52. doi
2. “PACMAN” Trial (Lancet) https://www.thelancet.com/journals/lancet/article/PIIS0140-6736(05)67061-4/abstract