Secondary Logo

Evaluation of Pulmonary Artery Pressure Measurements in Severe Pulmonic Valve Insufficiency in the Absence of Tricuspid Regurgitation

Mackersey, Kiri, BSc, BHB, MBChB; Skubas, Nikolaos, MD, FASE; Lichtman, Adam, MD, FASE

doi: 10.1213/XAA.0000000000000699
Case Reports: Echo Rounds
Free
SDC

From the NewYork-Presbyterian Weill Cornell Medical Center, New York, New York.

Accepted for publication November 28, 2016.

Funding: None.

The authors declare no conflicts of interest.

Supplemental digital content is available for this article. Direct URL citations appear in the printed text and are provided in the HTML and PDF versions of this article on the journal’s website.

Address correspondence to Kiri Mackersey, BSc, BHB, MBChB, c/o Department of Anesthesia, Montefiore Hospital, 111 East 210th St, Bronx, NY 10467. Address e-mail to kirimack@hotmail.com.

A 51-year-old woman with a history of heritable pulmonary arterial hypertension, a giant pulmonary artery (PA) aneurysm, right ventricular outflow tract (RVOT) hypertrophy, and severe pulmonic valve (PV) insufficiency presented for aneurysm repair and PV replacement. After an uneventful induction of general endotracheal anesthesia, a transesophageal echocardiography (TEE) examination revealed severe right ventricular (RV) hypertrophy (Supplemental Digital Content, Supplemental Video 1, http://links.lww.com/AA/B635).

The PA catheter (PAC) could not be advanced secondary to severe pulmonic insufficiency (PI) and RVOT hypertrophy causing localized obstruction to the RVOT in the subpulmonic region. Repeated attempts at PAC positioning were not made to avoid trauma to the PA aneurysm (Supplemental Digital Content, Supplemental Video 2, http://links.lww.com/AA/B636). Intraoperative TEE examination was used to evaluate RV function and calculate PA systolic and diastolic pressures (PASP, PADP; Figure). The PAC remained in the RV without evidence of arrhythmia, and RV pressures were measured directly from the catheter.

Figure

Figure

The measurements of PA pressures were used initially as a baseline for comparison with the pressures post-repair. Unfortunately, after the aneurysm repair, the pulmonary pressures were significantly worse. Upon remeasuring of the gradients, over time, we were able to show a beneficial response to nitric oxide and milrinone in a patient with potentially fixed pulmonary vascular resistance, due to long-standing disease.

Continuous-wave Doppler (CWD) may be used to measure high velocities across a stenotic or regurgitant valve orifice. Velocity is converted into a pressure gradient using the simplified Bernoulli equation1: pressure gradient = 4(V2). The simplified Bernoulli equation provides the peak instantaneous pressure gradient.

The PV may be well-aligned for Doppler interrogation in the transgastric RV basal view, the transgastric inflow–outflow view, or upper esophageal aortic arch short-axis view.2 The transgastric inflow–outflow view was used in this case due to superior parallel Doppler alignment (Supplemental Digital Content, Supplemental Video 2, http://links.lww.com/AA/B636). In comparison, the upper esophageal aortic arch short-axis view and RV basal views were relatively distorted by the giant PA aneurysm.

PI is common (present in up to 88% of patients).1,3 The PI velocity reflects the instantaneous gradient between the PA and the RV. At end-diastole, in the absence of pulmonic stenosis, the PI velocity (measured by CWD and demonstrated in the Figure by the white X) may be used to derive the transpulmonic pressure gradient—using the simplified Bernoulli equation. The PADP is calculated by adding mean RA pressure1 (either measured invasively, with a central venous catheter, or estimated, by assessing inferior vena cava diameter and respiratory variation using transthoracic echo in a spontaneous breathing patient).4 The mean PA pressure may be calculated using the peak PI velocity in place of the end-diastolic velocity. In the presence of pulmonic stenosis, flow acceleration across the stenosis will produce an elevated gradient, reflecting the stenotic lesion. The PA systolic pressure was calculated as follows: RV systolic pressure minus mean transpulmonic pressure gradient. The RV systolic pressure was measured by PAC and the mean transpulmonic pressure was derived from the PV velocity time integral (VTI; demonstrated in the Figure).

The calculations for PADP are made as follows:

Step 1. Obtain central venous pressure (CVP) by direct measurement, using central venous access (10 mm Hg).

Step 2. Calculate the end-diastolic pressure gradient.

The end-diastolic pressure gradient is derived from the end-diastolic velocity using the Bernoulli equation (pressure gradient = 4[V2]) as follows:

End-diastolic pressure gradient = 4(end-diastolic velocity2)

= 4(2.052)

= 17 mm Hg

Step 3. Calculate the PADP.

End-diastolic pressure gradient + CVP = PADP

17 mm Hg + 10 mm Hg = 27 mm Hg

RV systolic pressures, measured by the PAC in the RV, equaled 75/8. The mean transpulmonic pressure gradient was derived from the VTI of antegrade systolic flow through the PV and equaled 6 mm Hg (Figure). Subtraction of the mean transpulmonic pressure gradient (6 mm Hg) gives a PASP of 69 mm Hg. The calculation is made as follows:

Step 1: Obtain RV systolic pressure (measured directly from RV PAC) (75 mm Hg).

Step 2: Measure mean transpulmonic pressure gradient by tracing the VTI of antegrade systolic pulmonic flow, from which the TEE derives the pressure gradient (6 mm Hg).

Step 3: Calculate the PASP.

RV systolic pressure – mean transpulmonic pressure gradient = PASP

75 mm Hg – 6 mm Hg = 69 mm Hg

The tricuspid regurgitation (TR) velocity is routinely used to estimate the PA systolic pressure1; however, TR jets are not always present. Several investigators5,6 have found that PADP by PI was measurable in up to 89% of patients with PI, using TEE,6 making this a useful technique in the assessment of PADP in patients without pulmonary arterial hypertension or PI as the primary diagnosis.5,6 In a study of patients with coronary artery disease, an elevated end-diastolic pressure gradient by PI > 5 mm Hg was associated with a lower ejection fraction (odds ratio 3.7 of ejection fraction < 55%, 95% confidence interval 2.2–6.1), worse New York Heart Association functional status, and lower metabolic equivalents on treadmill testing.5 These investigators found that the end-diastolic pressure gradient could be measured as easily as a TR jet on Doppler echocardiographic examination, and elevated gradients were highly specific for both systolic and diastolic dysfunction.5

In patients who are either at greater risk for devastating PAC complications, or in patients in whom PAC placement is difficult, noninvasive measurement of PA mean, systolic, and diastolic pressures is possible via the use of Doppler interrogation of the PI jet. In addition, measurement of right heart pressures with a PI jet is a viable alternative in patients without a TR jet.

Back to Top | Article Outline

Patient Consent Statement

The images and content have been deidentified. None of the 18 private health information (PHI) elements are contained in this report. In addition, written consent for publication of this deidentified case has been obtained from the patient.

Back to Top | Article Outline

DISCLOSURES

Name: Kiri Mackersey, BSc, BHB, MBChB.

Contribution: This author helped conduct the study, analyze the data, and prepare the manuscript.

Name: Nikolaos Skubas, MD, FASE.

Contribution: This author helped analyze the data and prepare the manuscript.

Name: Adam Lichtman, MD, FASE.

Contribution: This author helped conduct the study, analyze the data, and prepare the manuscript.

This manuscript was handled by: Roman M. Sniecinski, MD.

Back to Top | Article Outline

REFERENCES

1. Quiñones MA, Otto CM, Stoddard M, Waggoner A, Zoghbi WADoppler Quantification Task Force of the Nomenclature and Standards Committee of the American Society of Echocardiography. Recommendations for quantification of Doppler echocardiography: a report from the Doppler Quantification Task Force of the Nomenclature and Standards Committee of the American Society of Echocardiography. J Am Soc Echocardiogr. 2002;15:167–184
2. Hahn RT, Abraham T, Adams MS, et alGuidelines for performing a comprehensive transesophageal echocardiographic examination: recommendations from the American Society of Echocardiography and the Society of Cardiovascular Anesthesiologists. J Am Soc Echocardiogr. 2013;26:921–964
3. Yoshida K, Yoshikawa J, Shakudo M, et alColor Doppler evaluation of valvular regurgitation in normal subjects. Circulation. 1988;78:840–847
4. Rudski LG, Lai WW, Afilalo J, et alGuidelines for the echocardiographic assessment of the right heart in adults: a report from the American Society of Echocardiography endorsed by the European Association of Echocardiography, a registered branch of the European Society of Cardiology, and the Canadian Society of Echocardiography. J Am Soc Echocardiogr. 2010;23:685–713
5. Ristow B, Ahmed S, Wang L, et alPulmonary regurgitation end-diastolic gradient is a Doppler marker of cardiac status: data from the Heart and Soul Study. J Am Soc Echocardiogr. 2005;18:885–891
6. Kasper J, Bolliger D, Skarvan K, Buser P, Filipovic M, Seeberger MDAdditional cross-sectional transesophageal echocardiography views improve perioperative right heart assessment. Anesthesiology. 2012;117:726–734

Supplemental Digital Content

Back to Top | Article Outline
© 2018 International Anesthesia Research Society