Diagnosing PAH

Nonspecific symptoms can lead to delay in diagnosis1-3

The diagnostic process begins after clinical suspicion based on symptoms and physical exam. However, symptoms of PAH are nonspecific, which can lead to delayed evaluation and diagnosis.1-3 Delayed diagnosis is common; thus patients often are diagnosed at FC III or IV.4

Symptom onset

Right ventricular dysfunction image

Symptoms are related to right ventricular dysfunction5

Typical presentation includes exertional symptoms6

  • Dyspnea
  • Fatigue

Due to nonspecific symptoms, the time between symptom onset and diagnosis is often >2 years3

Diagnosis

As disease progresses, symptoms start to occur at rest as the RV fails to compensate against the increased PVR6

  • Syncope
  • Lower extremity edema
  • Abdominal distention
  • Angina

Common misdiagnoses or comorbid conditions that delay diagnosis7,8:

  • PH-LHD
  • COPD
  • Asthma
  • Obesity

PAH diagnostic criteria

Clinical characteristics of PAH are nonspecific1,2 and are mainly related to progressive RV dysfunction5

PAH diagnosis

A series of tests may be performed to confirm diagnosis and identify an optimal therapeutic approach. Diagnosis begins with a medical assessment that provides information about risk factors that may predispose a patient toward a particular classification of PAH as well as facilitate decisions about further diagnostic testing.9

Elements of PAH diagnosis9:

  • Signs and symptoms
  • Physical examination
  • Laboratory tests
  • Chest x-ray
  • Echo
  • RHC
Body illustration showing non specific clinical characteristics, labeled by number based on the criteria evaluated in the diagnosis of PAH
    • Dizziness and/or lightheadedness8
    • Presyncope/Syncope8
  1. Cough8
  2. Rapid, hard, or irregular heartbeat (palpitations)8
  3. Chest pain (angina)8
    • Dyspnea on exertion8
    • Dyspnea at rest8
  4. Swollen abdomen (ascites)8
  5. Swollen legs (edema)8
  6. Swollen ankles (edema)8

Feeling tired or worn out (fatigue)8

Diagnostic investigations

Cardiac

  • EKG
  • Echo
  • Cardiac MRI

Respiratory

  • Pulmonary function test
  • Arterial blood gases
  • Overnight oximetry

Blood

  • PAH serology (eg, antinuclear antibodies)
  • Genetics

Imaging

  • Chest radiograph
  • V/Q scan
  • High-resolution CT
  • CTPA
  • MRI
  • Abdominal ultrasound
  • CT pulmonary angiography
  • FDG-PET

Exercise

  • CPET
  • 6-minute walk test (see downloadable how-to guide)

Get your guide to learn more about administering the 6‑minute walk test

Download How-To Guide

Physical exam findings6

Extracardiac exam findings

Extracardiac basic exam girl silhouette
  • Jugular vein distension
  • Hepatomegaly
  • Peripheral edema
  • Ascites
  • Lung examination is usually normal

Cardiac findings that reflect RV functional and structural changes

Heart illustration of the right ventricular
  • Left parasternal shift
  • Loud pulmonary component of the second heart sound
  • Pansystolic murmur of tricuspid regurgitation
  • Diastolic murmur of pulmonary insufficiency
  • RV third heart sound

Echocardiographic evaluation

The Echo can be used to assess variables of pulmonary hypertension. However, RHC is required to confirm diagnosis.10,11

Probability of PH based on Echo findings11

Echocardiographic evaluation chart showing the probability of PH. Based on Echo findings
Echocardiographic evaluation chart showing the probability of PH. Based on Echo findingsEchocardiographic evaluation chart showing the probability of PH. Based on Echo findingsEchocardiographic evaluation chart showing the probability of PH. Based on Echo findings
Image Description

Probability of PH based on Echo findings11

Low:

  • Peak tricuspid regurgitant velocity is ≤2.8 m/s or not measurable with no presence of other echocardiographic signs suggestive of pulmonary hypertension

Intermediate:

  • Peak tricuspid regurgitant velocity is ≤2.8 m/s or not measurable with presence of other echocardiographic signs suggestive of pulmonary hypertension
  • Peak tricuspid regurgitant velocity is 2.9 to 3.4 m/s or with no presence of other echocardiographic signs suggestive of pulmonary hypertension

High:

  • Peak tricuspid regurgitant velocity is 2.9 to 3.4 m/s with presence of other echocardiographic signs suggestive of pulmonary hypertension
  • Peak tricuspid regurgitant velocity is >3.4 m/s
Adapted from Galiè N, et al. Eur Heart J. 2016;37(1):67-119.

Echo findings suggestive of RV dysfunction in PH

Echo of the heart that the progressive dilation of the RV and RA in PAH
Images courtesy of Anjali Vaidya, MD, FACC, FASE, FACP. Pulmonary Hypertension, Right Heart Failure & CTEPH Program, Temple University Hospital.

The Echos above show the progressive dilation of the RV and RA in PAH. In end-stage PAH, the RV may cause the interventricular septum to bow outward and compress the LV. Other signs of RV dysfunction that can be found on Echo include12,13:

  • Presence of pericardial effusion
  • Ratio between RV and LV basal diameter >1
  • Loss of IVC inspiratory collapse
  • Tricuspid regurgitation
  • Increased RV systolic dysfunction
  • TAPSE

What are the recent advancements in Echo use in PAH?

Read Articles

RHC is required for a definitive diagnosis of WHO Group 1 PAH10,11

The 2015 ESC/ERS Guidelines recommend that patients with unexplained exertional dyspnea, syncope, and/or signs of RV dysfunction should be assessed for suspected PH/PAH using transthoracic echocardiography with a confirmed diagnosis ultimately dependent on hemodynamic results obtained from RHC.11

Illustration of right heart catheterization definitive diagnosis of WHO Group 1 PAH
Image Description
  • PAWP ≤15 mm Hg
  • PVR* >3 WU
  • mPAP ≥25 mm Hg(at rest)
    • Normal11: 14 ± 3 mm Hg
    • Upper limit of normal11: ~20 mm Hg
*PVR = (mPAP – PAWP) / CO.102018 WSPH treatment guidelines recommended an update to the diagnostic criteria for PAH: PAWP ≤15 mm Hg, PVR ≥3 WU, and mPAP >20 mm Hg (at rest).10

Hemodynamic values obtained during RHC11:

  • Confirm diagnosis of PAH
  • Evaluate severity of PAH
  • Assess congenital heart defects
  • Exclude left-side heart disease
  • Assess response to vasodilator challenge
  • Assess key hemodynamic parameters
  • Guide treatment decisions

Find the PAH ICD-10 codes your office may need

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Diagnostic algorithm

The diagnostic process begins after clinical suspicion of PH based on symptoms and physical examination.11

Although many tests can hone suspicion of PAH, an RHC must be performed to definitively diagnose PAH. Current treatment guidelines recommend that PAH patients be evaluated at a PAH center for confirmation.11

Download the diagnostic algorithm flowchart

A guide that goes through sequential steps of testing and decision making to help reach a possible diagnosis of PAH.

Download of the diagnostic algorithm flowchart to help reach a possible diagnosis of PAH

What’s the prognosis for a patient diagnosed with PAH?

Establishing PAH Prognosis

Baseline risk assessment is critical

Treatment guidelines require an objective, multiparameter risk assessment upon diagnosis.11 The baseline risk assessment informs prognosis and treatment decisions.14

2018 WSPH Guidelines recommend routine risk assessments every 3 to 6 months.14 These formal risk calculations can help you assess your patients.

Individual parameters should not be relied on for risk stratification in PAH. A multiparameter risk calculation provides a better estimation of short- and long-term prognosis.11

Monitor your patients’ risk status to determine whether treatment changes are needed

Integrating Risk Assessment
CO=cardiac output; COPD=chronic obstructive pulmonary disease; CPET=cardiopulmonary exercise test; CT=computed tomography; CTEPH=chronic thromboembolic pulmonary hypertension; CTPA=CT pulmonary angiogram; DLco=diffusing capacity for carbon monoxide; ECG=electrocardiography; Echo=echocardiogram; ESC/ERS=European Society of Cardiology/European Respiratory Society; EKG=electrocardiogram; FC=Functional Class; FDG-PET=fluorodeoxyglucose-positron emission tomography; HIV=human immunodeficiency virus; ICD=International Classification of Diseases; IVC=inferior vena cava; LV=left ventricle; mPAP=mean pulmonary arterial pressure; MRI=magnetic resonance imaging; PAWP=pulmonary arterial wedge pressure; PFT=pulmonary function test; PH=pulmonary hypertension; PH-LHD=pulmonary hypertension due to left heart disease; PVOD/PCH=PAH with overt features of venous/capillaries; PVR=pulmonary vascular resistance; RHC=right heart catheterization; RV=right ventricle; TAPSE=tricuspid annular plane systolic excursion; WHO=World Health Organization; WU=Wood unit; WSPH=World Symposium on Pulmonary Hypertension.References: 1. Bishop BM, et al. Pharmacotherapy. 2012;32(9):838-855. 2. McLaughlin VV, et al. J Am Coll Cardiol. 2009;53(17):1573-1619. 3. Rich S, et al. Ann Intern Med. 1987;107(2):216-223. 4. Badesch DB, et al. Chest. 2010;137(2):376-387. 5. Lai YC, et al. Circ Res. 2014;115(1):115-130. 6. Rich JD, Rich S. Circulation. 2014;130(20):1820-1830. 7. Hussain N, et al. Pulm Circ. 2016;6(1):3-14. 8. Brown LM, et al. Chest. 2011;140(1):19-26. 9. Wertheim BM, et al. Adv Pulm Hypertens. 2018;16(3):112-119. 10. Simonneau G, et al. Eur Respir J. 2019;53(1):1801913. 11. Galiè N, et al. Eur Heart J. 2016;37(1):67-119. 12. Forfia PR, Vachiéry JL. Am J Cardiol. 2012;110(6 suppl):16S-24S. 13. Roberts JD, Forfia PR. Pulm Circ. 2011;1(2):160-181. 14. Galiè N, et al. Eur Respir J. 2019;53(1):1801889.