Diagnosing PAH

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Nonspecific symptoms can lead to delay in diagnosis1-3

The diagnostic process begins after clinical suspicion based on symptoms and physical exam, and typically includes several different types of tests to help narrow down potential diagnoses—although an RHC is the only test that can definitely diagnose PAH. However, symptoms of right-sided heart dysfunction due to PAH are nonspecific, which can lead to delayed evaluation and diagnosis.1-4 Delayed diagnosis is common; thus patients often are diagnosed at FC III or IV.5

Symptom onset

Right ventricular dysfunction image

Symptoms are related to right ventricular dysfunction6

Typical presentation includes exertional symptoms7

  • Dyspnea
  • Fatigue

Due to nonspecific symptoms, the time between symptom onset and diagnosis is often >2 years4

Diagnosis

As disease progresses, symptoms start to occur at rest as the RV fails to compensate against the increased PVR7

  • Syncope
  • Lower extremity edema
  • Abdominal distention
  • Angina

Common misdiagnoses or comorbid conditions that delay diagnosis8,9:

  • PH-LHD
  • COPD
  • Asthma
  • Obesity

PAH diagnostic criteria

Clinical characteristics of PAH are nonspecific1,2 and are mainly related to progressive RV dysfunction6

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.10

Elements of PAH diagnosis10:

  • Signs and symptoms
  • Physical examination
  • Laboratory tests
  • Chest x-ray
  • Echocardiography
  • RHC
Body illustration showing non specific clinical characteristics, labeled by number based on the criteria evaluated in the diagnosis of PAH
  1. Dizziness and/or lightheadedness9
    • Presyncope/Syncope9
  2. Cough9
  3. Rapid, hard, or irregular heartbeat (palpitations)9
  4. Chest pain (angina)9
    • Dyspnea on exertion9
    • Dyspnea at rest9
  5. Swollen abdomen (ascites)9
  6. Swollen legs (edema)9
  7. Swollen ankles (edema)9

Feeling tired or worn out (fatigue)9

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)

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Physical exam findings7

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

Echocardiography evaluation

The Echo can be used to assess variables of pulmonary hypertension. However, RHC is required to confirm diagnosis.4,11

Probability of PH based on Echo findings12

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
Adapted from Galiè N, et al. Eur Heart J. 2016;37(1):67-119.
Image Description

Probability of PH based on Echo findings12

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

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 include13,14:

  • 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 PAH4

The 2022 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.4

Illustration of right heart catheterization definitive diagnosis of WHO Group 1 PAH
*PVR = (mPAP – PAWP) / CO.11
Image Description
  • PAWP ≤15 mm Hg
  • PVR* >2 WU
  • mPAP >20 mm Hg
    • Normal12: 14 ± 3 mm Hg

Hemodynamic values obtained during RHC4:

  • 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

Find PAH ICD-10 Codes

Diagnostic algorithm

The diagnostic process begins after clinical suspicion of PH based on symptoms and physical examination.4

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.4

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 Flowchart (PDF)
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 recommend calculating patient risk status at baseline to inform prognosis and initial treatment decisions. The 2022 ESC/ERS Guidelines further recommend risk assessment be performed as often as every 3 months; routine risk assessment can help you adjust your management plan according to risk-based treatment algorithms.4,12,15

An objective, multiparameter risk assessment is required because no single data point (eg, NT-proBNP) provides sufficient prognostic information on its own.12 Therefore, risk assessments should incorporate information derived from several sources, including clinical assessment, exercise testing, laboratory testing, Echo, and RHC.4

Perform routine risk assessment to optimize your use of PAH treatment algorithms

Integrating PAH 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. Humbert M, et al. Eur Heart J. 2022;43(38):3618-3731. 5. Badesch DB, et al. Chest. 2010;137(2):376-387. 6. Lai YC, et al. Circ Res. 2014;115(1):115-130. 7. Rich JD, Rich S. Circulation. 2014;130(20):1820-1830. 8. Hussain N, et al. Pulm Circ. 2016;6(1):3-14. 9. Brown LM, et al. Chest. 2011;140(1):19-26. 10. Wertheim BM, et al. Adv Pulm Hypertens. 2018;16(3):112-119. 11. Simonneau G, et al. Eur Respir J. 2019;53(1):1801913. 12. Galiè N, et al. Eur Heart J. 2016;37(1):67-119. 13. Forfia PR, Vachiéry JL. Am J Cardiol. 2012;110(6 suppl):16S-24S. 14. Roberts JD, Forfia PR. Pulm Circ. 2011;1(2):160-181. 15. Galiè N, et al. Eur Respir J. 2019;53(1):1801889.