Diagnosing Primary Pulmonary Hypertension (PPH)

The Electrocardiogram: The electrocardiogram commonly shows right axis deviation and right ventricular hypertrophy with secondary T-wave changes but does not necessarily parallel the severity of the underlying pulmonary hypertension. Atrial fibrillation is a particularly uncommon rhythm in PPH and may not be well-tolerated because of the dependence upon atrial systole for ventricular filling.

Imaging: Chest Radiograph: The chest radiograph shows evidence of pulmonary hypertension in over 90 percent of cases. Prominence of the main pulmonary artery occurs in 90 percent, hilar vessel enlargement in 80 percent, and pruning of the vessels with hyperlucent lung periphery in 51 percent. While a completely normal chest x-ray film speaks against the diagnosis, it should be noted that 6 percent of patients with PPH enrolled in the NIH registry had a normal radiograph.

Echocardiography (Echo) PPH Diagnosis  The echocardiogram can be useful to look for myocardial dysfunction, valvular disease, or congenital heart disease. The typical echocardiographic appearance of the patient with PPH shows right ventricular and right atrial enlargement with a normal to reduced left ventricular cavity. Pulmonic and tricuspid insufficiency is also easily detected with Doppler interrogation. Reversal of the normal septal curvature associated with right ventricular pressure overload states is seen in advanced disease. Hemodynamic correlations between the pulmonary vascular resistance and echocardiographic findings reveal an inverse relationship between left ventricular internal dimension and pulmonary vascular resistance, suggesting that underfilling of the left ventricle is a reflection of the severity of the pulmonary vascular disease. Doppler studies have also shown a redistribution of left ventricular filling from early to late diastole as a reflection of reduced compliance of the left ventricle. Doppler ultrasound can be used to noninvasively determine the pulmonary artery pressure. Most commonly, the magnitude of the tricuspid regurgitant flow velocity can be determined and enhanced using saline solution contrast to give relatively reproducible measurements of the right ventricular systolic pressure. Pulmonic valve insufficiency is frequently seen, and characteristics of the pulmonic regurgitant flow velocity or changes in the systolic flow velocity profile across the pulmonic valve can also be used to estimate pulmonary artery pressure noninvasively. Recently, transesophageal echocardiography has been employed in the evaluation of patients with pulmonary hypertension. It has an advantage of offering precise assessment of intracardiac defects and is very sensitive in the detection of a patent foramen ovale.

Ventilation-perfusion scintigraphy: It is mandatory that patients with pulmonary hypertension undergo ventilation-perfusion lung scanning in order to rule out chronic thromboemboli as the cause of the elevated pulmonary artery pressure. In PPH, the lung scan is either normal or low probability with small, patchy defects. Conversely, in thromboembolic pulmonary hypertension, the lung scan demonstrates at least one major ventilation-perfusion mismatch, often two or more. Therefore, a normal or low probability lung scan rules out thromboembolic pulmonary hypertension, and no further workup is necessary in this regard.

Pulmonary angiography: If the lung scan shows one or more segmental, or greater, ventilation-perfusion mismatches, an angiogram should be performed to rule out thromboembolism. While care should be exercised, pulmonary hypertension is not a contraindication to pulmonary angiography. In thromboembolic pulmonary hypertension, the clots are actually incorporated into the wall of the pulmonary artery and endothelialized so the angiogram may underestimate the extent of obstruction or be difficult to interpret. It may be necessary to employ angioscopy or magnetic resonance imaging in these cases. Angioscopy has had very limited application and is performed in few centers. It should not be performed except in those centers with considerable experience in the diagnostic evaluation of thromboembolic pulmonary hypertension.

Radionuclide angiocardiography: Radionuclide angiography can be utilized to assess both left and right ventricular function. However, caution should be taken in interpreting right ventricular ejection fractions in the presence of large right atrial and ventricular chambers, as true isolation of the right ventricular blood pool can be difficult. Right ventricular ejection fraction has been shown to be inversely proportional to the pulmonary artery pressure, although direct estimation of pulmonary artery pressure from the right ventricular ejection fraction is difficult.

MRI and ultrafast CT: As newer generations of MRI and CT scanners have evolved and software has improved, these imaging techniques have begun to offer great promise. Thrombi in proximal pulmonary arteries can be visualized without the necessity of an angiogram. In addition, ventricular and septal wall motion can be evaluated with calculation of right and left ventricular ejection fractions. The sensitivity of these tests for detection of central clots sufficient to cause pulmonary hypertension has not been determined, but this may become part of the diagnostic algorithm for PPH in the near future.

Pulmonary Function Testing: Abnormalities of pulmonary function may be present in PPH, particularly in the more advanced stages of the disease. The functional abnormalities may reflect derangements in either the mechanical or gas exchanging properties of the lung, with changes in the latter tending to be more prominent and disproportionately greater.

The functional abnormalities described in PPH include mild restrictive defects, small airways dysfunction, reduced carbon monoxide diffusing capacity (DCO), and impaired gas exchange as reflected by hypoxemia, hypocapnia (alveolar hyperventilation), and increased alveolar-arterial (A-a)O₂ gradient. Pulmonary function studies performed on the 187 patients in the PPH registry disclosed only mild reduction in lung volumes and no evidence of airways obstruction. The presence of moderate or severe restrictive or obstructive physiologic defects should suggest another diagnosis. Severe hypoxemia can occur in PPH, due either to intracardiac shunting via a patent foramen ovale or a severely depressed cardiac output with resultant mixed venous hypoxemia.

Cardiopulmonary Exercise Tests: Cardiopulmonary exercise tests are useful in the evaluation of patients with nonapparent causes of dyspnea since there is a characteristic pattern of ventilatory and circulatory response in the presence of pulmonary vascular disease. Since their sensitivity and specificity in the diagnosis of pulmonary hypertension are unknown, exercise testing is not considered essential in the evaluation of a patient with suspected PPH.

Connective Tissue (Collagen Vascular) Serologic Studies: Elevations in antinuclear antibodies are common in PPH and do not necessarily imply an associated collagen vascular disease. No specific pattern of antinuclear antibodies or titer has been consistently associated with PPH. As all of the collagen vascular diseases have been associated with pulmonary hypertension, it is possible that some patients with PPH have a collagen vascular disease that is confined to the lung.

PPH Diagnosis by Lung Biopsy: Lung biopsy is not considered essential in making an accurate diagnosis of PPH. In selected patients, a lung biopsy may be desirable or necessary to establish a diagnosis when confounding factors make the diagnosis otherwise uncertain. In that respect, an accurate diagnosis distinguishing the patient as having primary or secondary pulmonary hypertension may be very important with respect to prognosis and management. Transbronchial lung biopsy is of no value in the diagnosis of primary pulmonary hypertension because it does not sample blood vessels adequately and may also be risky due to elevated pulmonary artery pressure. Open lung biopsy, possibly using a thoracoscope, would be preferred. Care should be taken in obtaining the tissues, preferably from right or left lower lobes during full lung inflation. A correct histologic diagnosis can be difficult, and the pathologic material should be referred to a pathologist with expertise in pulmonary vascular disease.

PPH Diagnosis by Cardiac Catheterization: Cardiac catheterization is an absolutely the best tool available for confirming the diagnosis of PPH and for guiding management. Particular care should be taken to exclude intracardiac shunting and accurately ascertain left ventricular filling pressure with either a pulmonary capillary wedge pressure determination or directly with left ventricular catheterization. It should be recognized that left ventricular filling pressures may rise modestly in severe PPH due to diastolic dysfunction related to the pulmonary hypertension.Primary pulmonary hypertension diagnosis by cardiac catheterization is soemwhat painful and is an invasive procedureand with that comes the dangers of any invasive procedure. Make sure you talk with you doctor about all complications of a cardiac catheterization or any other procedure prior to consenting to this or any other procedure.

Pulmonary veno-occlusive disease can result in a gradient between the wedge pressure and left ventricular end-diastolic pressure, although the wedge pressure is usually normal or only mildly elevated. Typical of veno-occlusive disease is variability in wedge pressure determinations from various sites within the lung. Particular attention should be paid to the accurate measurement of the right atrial pressure, pulmonary artery pressure, and cardiac output, since they specifically relate to prognosis. Although the direct measurement of cardiac output through the Fick method is preferred in low cardiac output states, a reasonably accurate assessment using thermodilution can be obtained in most patients. Flow-directed catheters for the right side of the heart with an internal guidewire are commercially available and have been particularly helpful in positioning the catheter in the pulmonary artery.

LEGAL OPTIONS FOR PPH PATIENTS

If you or a loved one have been diagnosed with Primary Pulmonary Hypertension (PPH), then you may have a right to file a individual legal action against the manufacturers of the diet pills or others. Due to the nature of this serious and devastating disease process, PPH patients are urged to contact an attorney immediately after he or she has been informed of their Primary Pulmonary Hypertension diagnosis. Many important legal issues need to be addressed early after a PPH diagnosis, that can affect the outcome of the PPH litigation. Call us for a Free Confidential Consultation. Talk with a Board Certified Personal Injury Trial Lawyer about your legal rights of a PPH claim against the diet drug industry and others. No Fees or Expenses Charged unless we make a Recovery for You. 

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