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Hemodynamic Evaluation of Pulmonary Hypertension: Principles and Best Practices
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?
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
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.
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.
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
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%).
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
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
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)
62. PAWP waveform
• Step down in pressure from PAP
•Same principles as RAP measurement, but waveforms are delayed 0.08-0.12 s
Editor's Notes
To zero the transducer, the stopcock closest to the transducer
is closed to the patient. Remove the sterile protective cap from the stopcock port,
exposing the hemodynamic monitoring system to air. The monitor's zero function
key is activated to offset pressure in the transducer, setting the pressure to zero. Open
the stopcock to the patient and replace the sterile cap on the stopcock port. Zeroing
ensures that when the transducer stopcock is open to the patient and closed to air, the
only pressure on the transducer will be from the vessel/heart chamber being
monitored.
Damping describes the (usually exponential) decrease in amplitude of an oscillating system with time due to dissipation of energy by frictional forces.
Resonance describes the situation where a periodic force is applied to a system which is capable of oscillation. The amplitude of the resulting oscillation is greatest when the force is applied at a frequency which is equal to one of natural frequencies of oscillation (fundamental or harmonic frequencies) of the system. Thus if the frequency of the transmitted waveform is close to the natural resonant frequencies of the transducer system, the amplitude of the resultant waveform will be increased, and an artefactual raised reading will result.
Current guidelines recommend measurement of pulmonary artery wedge pressure (PAWP) at end-expiration. However, this recommendation is not universally followed and may not be physiologically appropriate. We investigated the performance of end-expiratory PAWP in the evaluation of precapillary pulmonary hypertension patients. 329 spontaneously breathing patients undergoing right heart catheterisation were retrospectively classified as having a precapillary, post-capillary or mixed phenotype based on standardised clinical criteria. Tracings were reviewed to compare end-expiratory PAWP with PAWP averaged throughout the respiratory cycle; these values were correlated with the clinical classifications. Predictors of large respirophasic variation in PAWP were determined. Elevated end-expiratory PAWP (>15 mmHg) occurred in 29% of subjects with precapillary phenotype. There were no differences in demographics or clinical history between those with elevated and normal end-expiratory PAWP. Those with elevated end-expiratory PAWP had greater right atrial pressure and respirophasic PAWP variation. Among all subjects, the magnitude of respirophasic variation in PAWP was positively correlated with body mass index and respirophasic variation in left ventricular end-diastolic pressure. A significant proportion of precapillary pulmonary hypertension patients have end-expiratory PAWP >15 mmHg. Spontaneous positive end-expiratory intrathoracic pressure may contribute; in those cases, PAWP averaged throughout respiration may be a more accurate measuremen
Current guidelines recommend measurement of pulmonary artery wedge pressure (PAWP) at end-expiration. However, this recommendation is not universally followed and may not be physiologically appropriate. We investigated the performance of end-expiratory PAWP in the evaluation of precapillary pulmonary hypertension patients. 329 spontaneously breathing patients undergoing right heart catheterisation were retrospectively classified as having a precapillary, post-capillary or mixed phenotype based on standardised clinical criteria. Tracings were reviewed to compare end-expiratory PAWP with PAWP averaged throughout the respiratory cycle; these values were correlated with the clinical classifications. Predictors of large respirophasic variation in PAWP were determined. Elevated end-expiratory PAWP (>15 mmHg) occurred in 29% of subjects with precapillary phenotype. There were no differences in demographics or clinical history between those with elevated and normal end-expiratory PAWP. Those with elevated end-expiratory PAWP had greater right atrial pressure and respirophasic PAWP variation. Among all subjects, the magnitude of respirophasic variation in PAWP was positively correlated with body mass index and respirophasic variation in left ventricular end-diastolic pressure. A significant proportion of precapillary pulmonary hypertension patients have end-expiratory PAWP >15 mmHg. Spontaneous positive end-expiratory intrathoracic pressure may contribute; in those cases, PAWP averaged throughout respiration may be a more accurate measuremen
CLINICAL INVESTIGATIONS
Overestimation of pulmonary artery occlusion pressure in pulmonary hypertension due to partial occlusion
Leatherman, James W. MD; Shapiro, Robert S. MD
Author InformationCritical Care Medicine: January 2003 - Volume 31 - Issue 1 - p 93-97
Abstract
Objective
To evaluate partial occlusion in patients with pulmonary hypertension with regard to a) the degree to which it leads to overestimation of pulmonary artery occlusion pressure (Ppao) and b) identification of factors that could enhance its recognition.
Design
Observational descriptive study.
Setting
Medical intensive care unit.
Patients
Fourteen patients with pulmonary hypertension and an increased pulmonary artery diastolic pressure (Ppad) − Ppao gradient (≥10 mm Hg).
Interventions
None.
Measurements and Main Results
The Ppao was recorded during partial occlusion (partial Ppao) and after catheter repositioning to obtain a lower, more accurate value (best Ppao). The error due to partial occlusion, defined as the difference between the partial Ppao and the best Ppao, was 13 ± 5 mm Hg (range, 6–21 mm Hg). The previously widened Ppad − Ppao gradient invariably narrowed during partial occlusion and then increased by 13 ± 5 mm Hg (range, 5–23) during the best Ppao measurement. There was a moderate correlation between the error due to partial occlusion (partial Ppao − best Ppao) and both the mean pulmonary artery pressure (r = .77, p < .01) and the Ppad − Ppao gradient (r = .79, p < .01).
Conclusions
Partial occlusion in patients with pulmonary hypertension may lead to significant overestimation of the Ppao and should be suspected when there is a substantial increase in the Ppao without a concomitant increase in the Ppad, as reflected by a marked narrowing of a previously widened Ppad − Ppao gradient.
Dehmer: V̇O2 (ml/min) = 125 (ml/min/m2) × body surface area (BSA,m2), with BSA calculated according to the formula of Dubois BSA
(m2) = 0.007184 × Weight (kg) 0.425 × Height (cm) 0.725.
LaFarge: V̇O2 (ml/min) = 138.1 – (X × logeage) + (0.378 × Heart Rate) × BSA (Men: X = 11.49; Women: X = 17.04);
Bergstra: V̇O2 (ml/min) = 157.3 × BSA + X – (10.5 × logeage)+ 4.8 (Men: X = 10; Women = 0).
Background—The Fick principle (cardiac output = oxygen uptake (V̇O2)/systemic arterio-venous oxygen difference) is used
to determine cardiac output in numerous clinical situations. However, estimated rather than measured V̇O2 is commonly
used because of complexities of the measurement, though the accuracy of estimation remains uncertain in contemporary
clinical practice.
Methods and Results—From 1996 to 2005, resting V̇O2 was measured via the Douglas bag technique in adult patients
undergoing right heart catheterization. Resting V̇O2 was estimated by each of 3 published formulae. Agreement between
measured and estimated V̇O2 was assessed overall, and across strata of body mass index, sex, and age. The study included
535 patients, with mean age 55 yrs, mean body mass index 28.4 kg/m2; 53% women; 64% non-white. Mean (±standard
deviation) measured V̇O2 was 241 ± 57 ml/min. Measured V̇O2 differed significantly from values derived from all 3 formulae,
with median (interquartile range) absolute differences of 28.4 (13.1, 50.2) ml/min, 37.7 (19.4, 63.3) ml/min, and 31.7 (14.4,
54.5) ml/min, for the formulae of Dehmer, LaFarge, and Bergstra, respectively (P<0.0001 for each). The measured and
estimated values differed by >25% in 17% to 25% of patients depending on the formula used. Median absolute differences
were greater in severely obese patients (body mass index > 40 kg/m2), but were not affected by sex or age.
Conclusions—Estimates of resting V̇O2 derived from conventional formulae are inaccurate, especially in severely obese
individuals. When accurate hemodynamic assessment is important for clinical decision-making, V̇O2 should be directly
measured. (Circulation. 2014;129:203-210.)
Cardiac output (CO) is an important diagnostic and prognostic tool for patients with ventricular dysfunction. Pulmonary hypertension patients
undergo invasive right heart catheterization to determine pulmonary vascular and cardiac hemodynamics. Thermodilution (TD) and direct Fick
method are the most common methods of CO determination but are costly and may be associated with complications. The latest generation
of impedance cardiography (ICG) provides noninvasive estimation of CO and is now validated. The purpose of this study was to compare ICG
measurement of CO to TD and direct Fick in pulmonary hypertension patients. Thirty-nine enrolled patients were analyzed: 44% were male
and average age was 50.8±17.4 years. Results for bias and precision of cardiac index were as follows: ICG vs. Fick (–0.13 L/min/m
2 and 0.46 L/min/m2), TD vs. Fick (0.10 L/min/m2 and 0.41 L/min/m2), ICG vs. TD (respectively, with a 95% level of agreement between –0.72 and 0.92 L/min/m2; CO correlation of ICG vs. Fick, TD vs. Fick, and ICG vs. TD was 0.84, 0.89, and 0.80, respectively). ICG provides an accurate,
useful, and cost-effective method for determining CO in pulmonary hypertension patients, and is a potential tool for following responses to
therapeutic interventions. (CHF. 2004;10(2 suppl 2):7–10)
Background—Hemodynamic assessment after volume challenge has been proposed as a way to identify heart failure with preserved ejection fraction. However, the normal hemodynamic response to a volume challenge and how age and sex affect this relationship remain unknown.
Methods and Results—Sixty healthy subjects underwent right heart catheterization to measure age- and sex-related normative responses of pulmonary capillary wedge pressure and mean pulmonary arterial pressure to volume loading with rapid saline infusion (100–200 mL/min). Hemodynamic responses to saline infusion in heart failure with preserved ejection fraction (n=11) were then compared with those of healthy young (<50 years of age) and older (≥50 years of age) subjects. In healthy subjects, pulmonary capillary wedge pressure increased from 10±2 to 16±3 mm Hg after ~1 L and to 20±3 mm Hg after ~2 L of saline infusion. Older women displayed a steeper increase in pulmonary capillary wedge pressure relative to volume infused (16±4 mm Hg·L−1·m2) than the other 3 groups (P≤0.019). Saline infusion resulted in a greater increase in mean pulmonary arterial pressure relative to cardiac output in women compared with men regardless of age. Subjects with heart failure with preserved ejection fraction exhibited a steeper increase in pulmonary capillary wedge pressure relative to infused volume (25±12 mm Hg·L−1·m2) than healthy young and older subjects (P≤0.005).
Conclusions—Filling pressures rise significantly with volume loading, even in healthy volunteers. Older women and patients with heart failure with preserved ejection fraction exhibit the largest increases in pulmonary capillary wedge pressure and mean pulmonary arterial pressure. (Circulation. 2013;127:55-62.)
Two nonblinded authors evaluated the validity of each of the four PAOP measurements by analyzing five preestablished criteria: (1) PAOP is less than the diastolic PAP, (2) the tracing is compatible with the atrial pressure waveform, (3) the fluoroscopic image demonstrates a stationary catheter after inflation, (4) free flow is present within the catheter, and (5) highly oxygenated blood (capillary) is obtained from the distal port while the catheter is in occlusion position.12 In every patient, we recorded the number of criteria present (one to five) in each of the four PAOP measurements. In addition, we identified in all patients the measurement with the highest number of criteria present that most likely reflected the LAP (namely, “best PAOP”) in order to assess for agreement in the PAOP measurements between left and right PAs with two different balloon inflation volumes.
Background:
Pulmonary artery occlusion pressure (PAOP) is used to differentiate patients with pulmonary hypertension (PH) associated with left-sided heart disease from other etiologies. Technical errors in the measurement of PAOP are common and lead to incorrect classification of the etiology of PH. We investigated the agreement among PAOP measurements obtained from both pulmonary arteries with balloon full (1.5 mL) and half (0.75 mL) inflation in patients undergoing right-sided heart catheterization for suspected PH.
Methods:
Thirty-seven patients suspected or known to have PH who underwent right-sided heart catheterization were included. Seventy-six percent had PH (mean pulmonary arterial pressure > 25 mm Hg). The validity of the measurements was assessed by using five preestablished criteria based on hemodynamic, fluoroscopic, and gasometric data. For each patient, the measurement that most likely represented the left atrial pressure was labeled “best PAOP.”
Results:
Seventy percent of all the PAOP measurements met at least four of the five preestablished criteria for validity. In patients with PH (n = 28), the mean ± SE PAOP was 23.1 ± 2 and 19.1 ± 2 mm Hg for balloon full and half inflation, respectively, in the right pulmonary artery and 23.54 ± 2 and 19.07 ± 2 mm Hg for balloon full and half inflation, respectively, in the left pulmonary artery (P = .05). Bland-Altman analysis revealed lower bias and narrower limits of agreement with balloon half inflation. Wedge angiography showed that some balloon inflations failed to occlude upstream flow, whereas others had collateral vessels draining after the occlusion.
Conclusions:
PAOP can be falsely elevated in patients with PH according to the balloon inflation volume. Balloon half inflation was safe and correlated with higher precision and lower bias in the PAOP measurements.
Pulmonary hypertension (PH) is defined as a resting mean pulmonary arterial pressure (PAP) of ≥ 25 m