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Evaluating suspected pulmonary hypertension: A structured approach

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Release date: June 1, 2018
Expiration date: May 31, 2019
Estimated time of completion: 1 hour

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ABSTRACT

Pulmonary arterial hypertension (PAH) is a common consideration when patients have unexplained signs of cardiopulmonary disease. Guidelines have been issued regarding diagnosis and management of this condition. Since multiple conditions can mimic components of PAH, the clinician should think about the patient’s total clinical condition before diagnosing and categorizing it. Proper evaluation and etiologic definition are crucial to providing the appropriate therapy. This review offers a case-based guide to the evaluation of patients with suspected PAH.

KEY POINTS

  • PAH has nonspecific symptoms, largely attributable to right ventricular dysfunction but seen in a host of other common cardiopulmonary ailments.
  • In a patient suspected of having pulmonary hypertension, it is important to take a methodic diagnostic approach to identify underlying contributors and minimize unnecessary testing.
  • Patients suspected of having PAH should be referred to a pulmonary hypertension center of excellence for evaluation and right heart catheterization.
  • Once testing is complete, therapy and management should be guided both by data obtained during the initial evaluation and by factors with prognostic significance. This approach has changed PAH from a disease with a grim outlook to one in which appropriate evaluation and guidance can improve patient outcomes.


 

References

Pulmonary arterial hypertension (PAH) is a hemodynamic disorder that affects small and medium-size pulmonary arteries through cellular proliferation and luminal narrowing. 1 Increased pulmonary vascular resistance causes restricted blood flow in these arteries, leading to elevated pulmonary arterial pressure and afterload on the right ventricle. Despite advances in therapy, death usually occurs as a result of right ventricular failure.

Updated World Health Organization classification of pulmonary hypertension
However, PAH is neither the only form of pulmonary hypertension nor the most common. Pulmonary hypertension, defined as an elevated pulmonary arterial pressure (≥ 25 mm Hg) on right heart catheterization, 1 has a myriad of causes. The World Health Organization (WHO) classifies pulmonary hypertension into 5 separate groups based on the pathophysiologic mechanism ( Table 1 ):
  • Group 1—PAH, due to narrowed pulmonary arteries
  • Group 2—due to left heart disease
  • Group 3—due to lung disease or hypoxia, or both
  • Group 4—due to chronic thromboembolism or other pulmonary artery obstruction
  • Group 5—due to uncertain or multifactorial causes.

Experts recognize the morbidity and mortality associated with pulmonary hypertension now more than in the past, and they emphasize recognizing it early. Guidelines for its diagnosis and treatment were updated in 2015. 1

Below, we use a case to discuss recommendations for initial evaluation and classification of pulmonary hypertension, particularly PAH.

A PATIENT SUSPECTED OF HAVING PULMONARY HYPERTENSION

A 63-year-old woman with a 25-pack-year history of tobacco use, as well as pulmonary embolism and coronary artery disease, presents to her primary care physician with exertional dyspnea. She had been a clerk at a hardware store and physically active until she took early retirement 8 months ago because of increasing fatigue. She initially felt the fatigue was simply “a sign of getting old.”

Since retiring, she has noticed the slow onset of progressive dyspnea on exertion. She can no longer climb more than 1 flight of stairs or walk more than 1 block. She also complains of mild, fluctuating edema in her lower extremities over the past month. She quit smoking 8 years ago after undergoing placement of a drug-eluting stent in the mid-left circumflex artery. After this, she received clopidogrel and was followed by a cardiologist for 2 years but stopped taking the medication because of bruising. She has not seen her cardiologist in more than 5 years.

She underwent elective right total knee arthroplasty 3 years ago, complicated by acute deep vein thrombosis in the right common femoral vein. Computed tomography (CT) at that time did not reveal pulmonary emboli. She received warfarin therapy for 3 months.

She reports no current cough, chest pain, lightheadedness, or syncope. She has no orthopnea, and she feels normal at rest.

Her family history is unremarkable, and she has had no exposure to illicit substances, environmental toxins, or dietary supplements. She takes aspirin 81 mg daily, metoprolol 25 mg twice daily, lisinopril 10 mg daily, and simvastatin 40 mg at bedtime.

Her primary care physician detects a murmur in the left lower sternal border and sends her for transthoracic echocardiography, which demonstrates mild right ventricular dilation, right atrial dilation, and mildly reduced right ventricular function. The calculated right ventricular systolic pressure is 69 mm Hg. The left ventricle shows mild concentric hypertrophy; the left atrium is normal in size.

DIAGNOSTIC EVALUATION OF SUSPECTED PULMONARY HYPERTENSION

Diagnostic algorithm for evaluating a patient suspected of having pulmonary hypertension
Figure 1.
Accurate diagnosis and classification of pulmonary hypertension requires both a high level of suspicion for the disease and appropriate diagnostic testing. Figure 1 depicts current recommendations for evaluating a patient suspected of having pulmonary hypertension. We will use this algorithm to guide proper risk stratification, classification, and invasive testing.

CLINICAL MANIFESTATIONS

Natural progression of disease in patients with pulmonary arterial hypertension
Figure 2. Natural progression of disease in patients with pulmonary arterial hypertension.
Clinical manifestations of pulmonary hypertension are invariably related to right ventricular dysfunction. As pulmonary arterial pressure and pulmonary vascular resistance increase, the right ventricle initially compensates to preserve cardiac output through up-regulation of sympathetic responses, dilation, and myocardial hypertrophy. For this reason, early clinical signs are either absent or nonspecific. 2 Eventually, however, the right ventricle can no longer compensate, 3 and cardiac output declines ( Figure 2 ).

Symptoms and signs. As in the patient described above, the first symptoms such as exertional dyspnea, fatigue, and lightheadedness usually arise in situations that call for increased cardiac output. 4 As right ventricular function worsens, symptoms start to occur at rest, and signs of increased right ventricular preload appear, such as abdominal and lower-extremity edema and pericardial effusion. Syncope is a sign of severe right ventricular dysfunction. 5

Physical examination. Look for signs of increased right ventricular loading and failure, eg:

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