Diagnostic evaluation of pulmonary hypertension

Authors
Lewis J Rubin, MD
William Hopkins, MD
Section Editor
Jess Mandel, MD
Deputy Editor
Kevin C Wilson, MD

Last literature review version 17.1: January 2009 | This topic last updated: February 10, 2009 (More)

INTRODUCTION — Patients suspected of having pulmonary hypertension (PH) undergo extensive diagnostic testing. The goal of diagnostic testing is to confirm that PH exists and to identify its underlying cause. The diagnostic tests used to evaluate a patient with suspected PH will be reviewed here. The definition, classification, epidemiology, etiologies, pathogenesis, clinical manifestations, treatment, and prognosis of PH are discussed separately. (See "Overview of pulmonary hypertension" and see "Pathogenesis of pulmonary hypertension" and see "Treatment of pulmonary hypertension").

NOMENCLATURE — The World Health Organization (WHO) classifies patients with PH into five groups based upon etiology. Patients in the first group are considered to have pulmonary arterial hypertension (PAH), whereas patients in the remaining four groups are considered to have pulmonary hypertension (PH) (show table 1). When all five groups are discussed collectively, the designation PH is generally used. We adhere to this nomenclature in the discussion that follows. The WHO classification system is described in detail elsewhere. (See "Overview of pulmonary hypertension", section on Classification).

DIAGNOSTIC TESTS — Numerous diagnostic tests may be used to evaluate a patient with suspected PH. The sequence in which the tests are performed is determined by the patient’s clinical history and physical exam. (See "Recommended diagnostic approach" below).

Chest radiograph — The characteristic chest radiograph shows enlargement of the central pulmonary arteries with attenuation of the peripheral vessels, resulting in oligemic lung fields (show radiograph 1) (show radiograph 2). Right ventricular enlargement (diminished retrosternal space) and right atrial dilatation (prominent right heart border) may also be seen. Occasionally, the underlying cause of the PH is apparent on the chest radiograph (eg, interstitial lung disease).

Electrocardiography — The electrocardiogram (ECG) may demonstrate signs of right ventricular hypertrophy or strain (show ECG 1). In addition, findings suggestive of chronic right ventricular overload may exist, including right axis deviation, an R wave/S wave ratio greater than one in lead V1, incomplete or complete right bundle branch block, or increased P wave amplitude in lead II (P pulmonale) due to right atrial enlargement (show figure 1 and show ECG 2). Most ECG signs are specific but not sensitive for the detection of right ventricular disease. ECG changes cannot determine disease severity or prognosis [1,2].

Echocardiography — Echocardiography is performed to estimate the pulmonary artery systolic pressure and to assess right ventricular size, thickness, and function (show echocardiogram 1). In addition, echocardiography can evaluate right atrial size, left ventricular systolic and diastolic function, and valve function, while detecting pericardial effusions and intracardiac shunts Atrial septal defect color Doppler 2 Ventricular septal defect small four chamber color Doppler echocardiogram [3,4].

Echocardiography uses Doppler ultrasound to estimate the pulmonary artery systolic pressure. This technique takes advantage of the tricuspid regurgitation that usually exists. The maximum tricuspid regurgitant jet velocity is recorded and the pulmonary artery systolic pressure (PASP) is then calculated:

PAP systolic = (4 x tricuspid jet velocity squared) + RAP

where RAP is the right atrial pressure estimated from the size and respiratory variation of flow in the inferior vena cava. A systolic pulmonary artery pressure greater than 40 mmHg, which corresponds to a tricuspid regurgitant velocity on Doppler echocardiography of 3.0 to 3.5 m/sec, is suggestive of PH [5]. (See "Principles of Doppler echocardiography").

Doppler echocardiography is limited when an adequate tricuspid regurgitant jet can not be identified, or underlying cardiopulmonary disease alters cardiac function. Despite this, it is more accurate than clinical history and physical examination in detecting PH [6,7].

Patients with PH may have echocardiographic signs of right ventricular pressure overload, including paradoxical bulging of the septum into the left ventricle during systole and hypertrophy of the right ventricular free wall and trabeculae (show echocardiogram 4) Pulmonary hypertension short axis echocardiogram. As the right ventricle fails, there is dilation and hypokinesis, septal flattening, right atrial dilation, and tricuspid regurgitation (show echocardiogram 6) Pulmonary hypertension four chamber echocardiogram. Tricuspid regurgitation is not due to an intrinsic abnormality of the tricu
References :
I am a Pharmacist: UpToDate Medical Reference