Marie M. Budev, DO, MPH, Alejandro C. Arroliga, MD, Herbert P. Wiedemann, MD, and Richard A. Matthay, MD

Disclosures

Semin Respir Crit Care Med. 2003;24(3) 

In This Article

Evaluation of the Patient with Chronic Cor Pulmonale

Symptoms and Signs

The development of pulmonary hypertension and right ventricular failure in a patient with chronic pulmonary disease has significant prognostic implications; accordingly, careful attention to early physical symptoms and signs is critical.[23] The symptoms of chronic cor pulmonale develop gradually over years. In patients with COPD, clinical signs may be masked by lung hyperinflation. Most patients initially have dyspnea, which becomes more severe as right ventricular failure occurs. Chest pain may occur and be difficult to differentiate from angina pectoris. In patients with severe COPD, orthopnea is common and is thought to be related to the effect of lung hyperinflation on venous return to the right side of the heart. With worsening right ventricular function, bloating and early satiety occur because of hepatic venous congestion and lower extremity edema.[49] Patients with COPD who develop peripheral edema have a 5-year survival rate of only 27 to 33%.[28] Peripheral edema may be due to other causes, such as hypoalbuminemia, and is not always present in patients with pulmonary hypertension. Edema is rarely present if the pCO2 is normal, and is not always present if the pCO2 is elevated.[50] A systolic left parasternal heave may indicate the presence of right ventricular hypertrophy, and tricuspid regurgitation murmur may indicate the presence of right ventricular dilation. Although the presence of a prominent jugular V wave may indicate tricuspid valvular regurgitation, jugular venous pressure may be difficult to assess in patients with marked lung hyperinflation because of variations in intrathoracic pressures. Accentuation of the second heart sound pulmonic component is an insensitive indication of pulmonary hypertension.[11]

Diagnostic Studies

The chest radiograph may show the presence of pulmonary hypertension or cor pulmonale and provide evidence regarding the etiology. (Also see the article by Kosiborod and Wackers in this issue of Seminars.) Parenchymal lung abnormalities such as hyperinflation may indicate the presence of emphysema or obstructive disease. Skeletal abnormalities such as kyphoscoliosis can be identified as well. The width of the right descending pulmonary artery on the chest radiograph may indicate the presence of pulmonary hypertension (Fig. 6). A width of > 16 mm has been shown to correlate with the presence of pulmonary hypertension in patients with COPD.[9] A width of > 18 mm of the left descending pulmonary artery is also associated with elevated pulmonary artery pressures.[9] In patients with COPD, a high cardiothoracic ratio is highly sensitive and 100% specific for the presence of pulmonary hypertension.[51] Although the chest radiograph may provide evidence for the presence of pulmonary hypertension, it cannot measure the degree of pulmonary artery pressure elevation. A globular heart may indicate right ventricular dilation or hypertrophy, which would be further supported by the presence of a decrease in the retrosternal air space on a corresponding lateral view.[11]

Figure 6.

Chest radiograph showing the increased width of the right descending pulmonary artery indicating the presence of pulmonary hypertension. (Courtesy of Dr. RA Matthay, New Haven, CT.)

Electrocardiographic evaluation for right ventricular hypertrophy is highly specific but not sensitive.[11] Echocardiography can show structural changes due to cor pulmonale or the presence of pulmonary hypertension (Fig. 7.) Gross examination of the right ventricle shows a decrease in its volume relative to its mass in cor pulmonale. The right ventricle becomes less crescent shaped and more concentric overall, similar to the changes that occur in the left ventricle.[52] Early echocardiographic evaluation of the right ventricle was limited by its crescent shape, its substernal location, and the presence of a large amount of artifact. With the advent of twodimensional echocardiography with Doppler and color Doppler imaging, the right ventricle was better visualized.[53] Echocardiography is sensitive in detecting severe elevation in pulmonary artery pressure but may be of limited value in the detection of mild to moderate elevations. Measurement of the peak velocity of the tricuspid valve regurgitation jet using Bernoulli's equation in the absence of tight ventricular outflow tract obstruction can provide an estimate of the pulmonary artery systolic pressure.[54] This technique is limited in patients with COPD because a satisfactory signal cannot be obtained. Pulmonary artery hypertension can also be detected by the measurement of the flow characteristics of the inferior vena cava, although this method has not been studied prospectively. Diastolic flattening of the interventricular septum occurs with progressive pulmonary hypertension and can be visualized by echocardiography, which may also indicate evidence of right ventricular overload.[5] The detection of right ventricular dimensions and wall thickening is limited by the inability to differentiate the right ventricular wall from its surrounding structures. Correlations between right ventricular wall thickness and right ventricular weight are poor even when measured at autopsy.[28] The measurement of the right ventricular diameter during diastole may indicate evidence of right ventricular enlargement. Transesophageal echocardiography does not seem to provide additional information in assessing the right ventricle. Three-dimensional echocardiography is being investigated in the assessment of pulmonary artery hypertension and right ventricular dimensions.[11]

Figure 7.

Echocardiogram indicating the evidence of structural changes secondary to cor pulmonale including diastolic flattening of the interventricular septum indicating volume overload of the right ventricle. (Courtesy of Dr. RA Matthay, New Haven, CT.)

The gold standard for the measurement of cardiac volumes and ejection fractions is contrast ventriculography as long as adequate separation of the cardiac chambers can be seen. Although pulmonary artery pressure cannot be calculated directly with this technique, there is an inverse relationship between the pressure measured at right-heart catheterization and right ventricular ejection fraction in patients with COPD.[5]

Computed tomography (CT) can be used to determine the pulmonary artery cross-section diameter, which correlates well with pulmonary artery pressure.[55] High-resolution CT scans (HRCT) can provide evidence of parenchymal disease. Magnetic resonance imaging (MRI) is becoming the reference standard for measuring ventricular dimensions because it provides the best image of the right ventricle.[56] MRI can also be used to identify regional right ventricular function to determine the impact of chronic pulmonary hypertension on global cardiac function.

The gold standard for the diagnosis of pulmonary hypertension remains right-heart catheterization. A thermodilution balloon catheter is inserted, and right atrial, right ventricular, pulmonary artery, and pulmonary artery occlusion pressures are measured. With pulmonary hypertension the pulmonary artery occlusion pressure should be normal; otherwise, left-heart catheterization may be needed.

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