Ryan Tedford, MD Medical University of South Carolina

1. Ryan J. Tedford, MD, FACC, FAHA, FHFSA
Peter C. Gazes Endowed Chair and Professor of Medicine
Section Chief, Heart Failure
Medical Director, Cardiac Transplant
Medical University of South Carolina, Charleston, SC
Hemodynamic Evaluation of Pulmonary
Hypertension— Principles and Best Practices
13TH ANNUAL NORTH CAROLINA RESEARCH TRIANGLE
PULMONARY HYPERTENSION SYMPOSIUM
November 5, 2021
@RyanTedfordMD

2. Disclosures
Medtronic/Accerelon –Steering Committees
Actelion/Merck – Hemodynamic Core Lab
Abiomed – Research Advisory Group
Consultant –United Therapeutics, Medtronic, Aria CV, Gradient,
Itamar, Edward LifeSciences, Eidos Therapeutics, Lexicon, CareDx
I Love Right Heart Catheterizations and Hemodynamics!
Ryan J. Tedford, MD

3. Objectives
1. Review best practices of the right heart
catheterization
2. Detail waveform interpretation including
considerations of how to accurately measure the
PAWP
3. Appraise importance of RHC timing and provocative
challenges in the diagnosis of PH

4. Two Basic and Critical Principles
1. Always perform a right heart catheterization BEFORE
starting any PAH specific therapy
2. PAH specific therapy is not recommended in LHD
2015 ERS/ESC PH
guidelines

5. Case
35 year old woman with IPAH, previously vasoreactive
(treated with calcium channel blocker therapy)
› Lost vasoreactivity – treated with riocuiguat and ambrisentan
› Progressive symptoms – near syncope and volume overload
› Referred for RHC prior to planned initiation of IV epoprostenol

6. RHC
SBP 96/70, HR 98
RA 9, RV 130/20, PA 130/60 (90), W 40
CO/CI - 4.5/2.6 (TD)
Nitroprusside – PA 115/61 (81), no PAWP or CO/CI recorded
Sent back to MICU
Phone call: What to do with the PAWP of 40mmHg? Should we start
epoprostenol or not?

7. Before you begin
Know what to expect
Get comfortable (you and the patient)!
Patient positioning
› Patient is supine with legs flat
› Right internal jugular access (or antecubital) unless contraindication
› No sedation is preferable; if absolutely necessary, premedication with oral
medication much preferred over IV administration

8. Before you begin
› Level the transducer in a supine
patient :
› Left atrium: Mid chest is halfway
between the anterior sternum and
the bed surface.
› Measure it!
› Zero the transducer
Kovacs g. Eur Respir J. 2013 Dec;42(6):1586-94.
*J Am Coll Cardiol. 2013;62(25_S)

9. General Principles –
RHC measurements
All pressure tracings must be accompanied by a simultaneous ECG tracing (directly
above or below the pressure tracing) which is used for timing and analysis of waveforms.
If PVC’s are present, the tracings should be re-recorded unless PVC burden is too high
to allow for a PVC-free recording.
All hemodynamic recordings should be taken while patient is breathing quietly and
spontaneously. No breath hold maneuvers should be used.1
Do not record any data while the patient is restless, talking, or coughing.
1Hoeper MM et al. Definitions and Diagnosis of PH.
J Am Coll Cardiol 2013;62:D42–50

10. Examining The Tracing Quality
If pressure tracings appear dampened (for example, no dichotic notch is seen on the PA
pressure tracing), re-flush the catheter and tubing to insure there are no air bubbles in
either.
Watson CA et al. Anaesthesia and Intensive Care Medicine (13), 2012, 116-120.
Maron BA…Tedford RJ. JACC 2020 Dec 1.

11. Examining The Tracing Quality
If catheter ringing is present, try flushing all tubing first, and if not successful,
introducing a small amount of blood back into the catheter may be helpful (to
change the resonant frequency) – must be careful to overdamp the signal.
Watson CA et al. Anaesthesia and Intensive Care Medicine (13), 2012, 116-120.
Maron BA…Tedford RJ. JACC 2020 Dec 1.

12. Dealing with Catheter Ringing
Lim MJ. Hemodynamic Rounds, 3rd edition, 2009
Maron BA…Tedford RJ. JACC 2020 Dec 1.

13. PAWP is the sole discriminator of PH – critical
to get it right
Maron BA…Tedford RJ. JACC 2020 Dec 1.

14. Key issues with PAWP measurement
How to measure the PAWP at rest?
› What is normal (<=15mmHg)?
› Where in the cardiac cycle?
› Where in the respiratory cycle?

15. What is the normal value of PAWP ?
1958 – The left atrial pressure averaged 2-3 mmHg 1
1975 – The « capillary » pressure is in the order of 6-9 mmHg
and may even reach 12 mmHg; …seems little affected by age.
It gives a good indication of the mean LAP provided that it does
not exceed 25 mmHg 2
2002 – The inclusion criteria were… a pulmonary capillary
wedge pressure < 15 mmHg, and PVR > 240 dyn·sec·cm-5
2007 – mean PAWP > 12 mmHg or LVEDP > 16 mmHg 4
2016 – PAWP ≥ 15 mmHg or LVEDP ≥16 mmHg 5
1. Wood P. Br Heart J. 1958;20:557-70. 2. Proceedings of the WHO
Symposium 1975. 3. Rubin LJ et al. N Engl J Med. 2002; 346:896-
903. 4. Paulus W et al. European Heart Journal (2007) 28, 2539–
2550. 5. Ponikowski P et al. Eur Heart J 2016; 37, 2129–2200

16. What is the normal PAWP?
The “normal PAWP” has creeped up over time
Many early studies considered a “normal PAWP” < 12
mmHg
Some of this may be due to use of respiratory “mean”
PAWP in early studies rather than end-expiration

17. Key issues with PAWP measurement
How to measure the PAWP at rest?
› What is normal (<=15mmHg)?
› Where in the cardiac cycle?
› Where in the respiratory cycle?

18. What does the PAWP mean?
In diastole (MV open): P1=P2=P3
If we measure at end-diastole:
PAWP = LA pressure = LV
end-diastolic pressure
(LVEDP)

19. mean PAWP vs end-diastolic PAWP
Pre C wave (end-diastole)
mean PAWP roughly ~ end-diastolic PAWP = LVEDP
average of
peak and
trough of a-
wave

20. November 9, 2021
20
Impact of mean PAWP (averaged over cardiac cycle)
vs end-diastolic PAWP
Large V waves were associated with
negative DPG (PAD-PAWP)

21. End-diastolic PAWP vs mean PAWP
Mean PAWP represents pressure “felt” by the pulmonary circulation from the LA
mean PAWP ~ End-diastolic PAWP
Maron BA…Tedford RJ. JACC 2020 Dec 1.
mean PAWP > End-diastolic PAWP

22. Hemnes A et al. Chest. 2018 Aug 24.S0012-3692(18)32250-5.

23. Recommendations for adequate PAWP/LVEDP measurement
In respect to the cardiac cycle: measuring at end-diastole closely
reflects LVEDP
› In sinus rhythm, average the a-wave.
› In atrial fibrillation, measure the pressure 130-160msec after the
onset of QRS and before the V wave
› To determine the PVR (pre-capillary component), would use mean
PAWP
The presence of large V waves should be reported as this strongly
suggest LHD regardless of the PAWP.
Vachiery, Tedford, De Marco WSPH . ERJ 2019 Jan 24;53(1).
Maron BA…Tedford RJ. JACC 2020 Dec 1.

24. Key issues with PAWP measurement
How to measure the PAWP at rest
› What is normal?
› Where in the cardiac cycle?
› Where in the respiratory cycle?

25. Sometimes significant respiratory variation
PAWP
PAP

26. Could end-expiration overestimate?
LeVarge…Channick R. Eur Respir J. 2014 August;44(2):425–434
• Respirophasic variation correlated with BMI (? COPD/air trapping)
• 29% had pre-capillary phenotype but end-exp PAWP >15
329pts
44% of the cohort had post-capillary phenotype (all with respiratory mean PAWP ≤ 15mmHg)
that would also have been misclassified!

27. Equal impact on PAWP and LVEDP
LeVarge et al. Eur Respir J. 2014 August;44(2):425–434
“Routine measurement of LVEDP, in addition to adding procedural risk, is subject to the
same debates regarding respiratory variability as PAWP.”
N=30

28. Effect of obesity
Average BMI 46.2 (10.2)
Jawad et al. Ann Am Thorac Soc 2017
Dec; 14(12): 1861-1863

29. Effect of loading conditions
Maurides SP, Blankinship D…Houston BA.
J Card Fail 2020 Oct 7

30. Effect of loading conditions
Maurides SP, Blankinship D…Houston BA.
J Card Fail 2020 Oct 7

31. Recommendations for adequate PAWP/LVEDP measurement
In respect to the respiratory cycle:
› PH-LHD: we continue to recommend the assessment of PAWP at
end-expiration; Measuring as mean of the respiratory cycle would
reclassify many post-capillary PH patients to pre-capillary disease. (PH-
LHD)
› Lung Disease: As a result of exaggerated changes in intrathoracic
pressures during the breathing cycle in patients with lung disease, a
floating average over several breaths (without a breath hold) is
suggested for measurement of mean pressures, including the pulmonary
artery wedge pressure.
› I report both when significant respiratory variation

32. Partial Occlusion
Leatherman JW, Shapiro RS. Crit Care Med.
2003;31(1):93-97

33. To pulmonary
capillaries and
pulmonary veins
Distal PA
Distal PA
To pulmonary
capillaries and
pulmonary veins
To main PA
To main PA
How to measure a PAWP sat

34. What is the data – PAWP Sat?
Viray M, Tedford RJ. Circ HF 2020 Nov;13(11):e007981.

35. Back to our case: Does the PAWP fit?

36. Does the PAWP fit?

37. Does the PAWP fit?
No PAWP sat drawn

38. Case: Course
PAWP obtained (balloon partially inflated)
End-expiratory PAWP 12-13mmHg
Epoprostenol started and titrated to effect with good results

39. Final Take Home Points - PAWP
Check a PAWP saturation whenever PAWP is elevated to
confirm a complete occlusion
Always consider the clinical situation and know what you
expect to find before starting your case
Vachiery, Tedford, De Marco WSPH . ERJ 2019 Jan 24;53(1).
Maron BA…Tedford RJ. JACC 2020 Dec 1.

40. Cardiac Output Assessment

41. Modified Fick vs. TD Cardiac Output
1Hoeper MM et al. AJRCCM 1999;160:535–541.
2Hillis, L. D et al. Am. J. Cardiol. 1986 May 1;57(13):1201-2.
3Cigarroa, RG et al. Am. J. Med. 1989. 86:417–420
4Stevens Jl et al. JAMA. 1985;253:2240-2242.
Gold standard for measuring cardiac output is the direct Fick
method – requires measuring oxygen uptake (V02)1
Two commonly clinically used methods:
› Thermodilution cardiac output – concerns for inaccuracies at low2 (or
high) cardiac output and severe TR3; measured in triplicate at end-
expiration if possible4
› Fick [Q = (V02)/(AV02 difference x10)]
› Modified Fick assumes fixed basal oxygen consumption (125 mL
of 02/min/m2) – may not be accurate in ill patients with PAH and
HF; pulse oximetry to estimate arterial saturations can lead to
error

42. Estimated V02 vs Direct V02
Narang N et al. Circulation. 2014;129:203-210.)
535 Patients

43. Fick vs. TD Cardiac Output
Hoeper MM et al. AJRCCM 1999;160:535–541.
Yung GL et al. CHF. 2004;10(2 suppl 2):7–10
TD vs. direct Fick bias =
0.19L/min

44. TDCO vs Estimated Fick and Association
with Mortality
44
Opotowsky A…Tedford RJ. JAMA Cardiology 2018

45. 45
Recommendations from 5th WSPH
(Nice)
 “The gold standard for CO measurement is the direct
Fick method, which requires direct measurement of the
oxygen uptake, a technique that is not widely available.
Therefore, it has become common practice in many
centers to use the indirect Fick method, which uses
estimated values for oxygen uptake derived from tables.
This approach is acceptable but lacks reliability.
Therefore, the preferred method of measuring CO is
thermodilution, which has been shown to provide
reliable measurements even in patients with very
low CO and/or severe tricuspid regurgitation.”
Hoeper MM et al. Definitions and Diagnosis of PH.
J Am Coll Cardiol 2013;62:D42–50

46. Timing of RHC for Diagnosis and Provocation
46

47. Why is timing important?
PAWP is not a constant number but a biological variable that is
affected by various factors, including fluid balance, intrathoracic
pressure, and others. 1
In many patients with left heart disease, it will be possible to at
least temporarily lower PAWP below 15 mm Hg with meticulous
afterload reduction and diuretic medication.2-3
Diuresis prior to RHC is common practice
1J Am Coll Cardiol. 2013;62(25_S)
2Lancet. 2011 Feb 19;377(9766):658-66
3Tampakakis E et al. JACC Heart Fail. 2015 Jan;3(1):9-16

48. Of 1174 patients with newly diagnosed cardiomyopathy
referred for endomyocardial biopsy, 616 had PAWP ≤
15 mmHg (52%).

49. Move toward earlier RHC?
Maron BA…Tedford RJ. JACC 2020 Dec 1.

50. 50
Vachiery, Tedford, De Marco WSPH . ERJ 2019 Jan 24;53(1).
What if done later? Provocative Testing

51. Fujimoto N et al. Circulation. 2013;127:55-62
Subjects with HFpEF exhibited a
steeper increase in PAWP relative to
infused volume than healthy young
and older subjects (P≤0.005).
No ‘healthy’ subject would have increased PAWP > 18mmHg with 500cc saline
Borlaug BA. Circ Heart Fail. 2014;7:2-4
Ages
Young: 36±8
Old: 64±6
HFpEF 73±7
Fluid loading

52. 18 pages long!
Exercise Hemodynamics ?

53. 1. Type and duration of exercise?
2. Patient positioning – supine, upright, or in-between?
3. Where to assess in the respiratory cycle?
4. Impact of catheter ringing on systolic and diastolic
pressures?
5. What is normal?
6. How to assess cardiac output?
Multiple Considerations

54. WSPH Provocative Testing Recommendations
• In patients with a PAWP between 13 and 15 mmHg and high/intermediate probability of
PH LHD, provocative testing should be considered to uncover PH due to LHD. For
technical reasons and reliability of pressure recording, a fluid challenge is preferred over
exercise in the approach of differential diagnosis.
• A PAWP of > 18 mmHg immediately after administration of 500 ml of saline over 5
minutes is considered abnormal.
• However, how this should impact management is unknown. If PAH specific therapies are
initiated in patients with “abnormal” response, caution should be exercised, including
close monitoring of response and side effects.
Vachiery, Tedford, De Marco WSPH . ERJ 2019 Jan 24;53(1).

55. Summary
1.A thorough and meticulously performed right heart
catheterization is critical to make the diagnosis of PH
(preferably by a hemodynamic nerd like me)
2.You must get the PAWP right!
3.Consider early RHC when establishing diagnosis and
provocative testing if concern for LHD

56. Thank you - @RyanTedfordMD
MUSC HF Cardiologists .
Ryan Tedford
Brian Houston
Dharini Ramu
Michael Craig
Benny Van Bakel
Tom Di Salvo
Dan Judge
Greg Jackson
Chak Inampudi
Daniel Silverman
Bear Coney
Michael Zile
Sheldon Litwin
Heart Failure Surgeons .
Lucas Witer
Nick Pope
Sanford Zeigler
Marc Katz
Arman Kilic

57. Other slides

58. Balloon Occlusion – Half Inflation
Chest. 2011 Jan; 139(1): 115–121.

59. Interpretation of Tracings

60. Right atrial waveform – where to measure
www.anaesthesiauk.com
www.phaonlineuniv.org
End-diastolic pressure:
• Pre-C wave point (ideal)
• Average the highest and lowest “a” wave pressure
• If no a-wave (afib), identify the “Z” point (line from end of QRS to atrial tracing)
Normal values (0-5 mmHg)

61. Pulmonary artery waveform
Dicrotic notch
Step up in diastolic pressure
when moving from RV to PA
Normal mPAP ≤ 20 mmHg

62. PAWP waveform
• Step down in pressure from PAP
•Same principles as RAP measurement, but waveforms are delayed 0.08-0.12 s