PULMONARY HYPERTENSION
PULMONARY HYPERTENSION
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Rajesh Shenoy
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Work-up of pulmonary hypertension
Work-up of pulmonary hypertension:
When a patient’s history, symptoms and signs suggest a high likelihood of pulmonary hypertension, the work-up consists of a complete history (including family history and that of conditions likely to result in pulmonary hypertension) and investigations that not only confirm the diagnosis, but also help in identifying an etiologic factor, in quantifying the severity of the disease, and in judging the likely success of medical management. Ideally, this work-up is carried out in centers dedicated to the management of PH that have the necessary multidisciplinary expertise. Figure 1 depicts a diagnostic algorithm for the diagnosis of pediatric PH.
General laboratory studies: These include a complete blood count, serum chemistries, urinalysis, and BNP. A chest X-Ray in older children and adolescents might show pulmonary oligemia with pruning of blood vessels. The cardiac apex is upturned, and the pulmonary notch is very prominent.
Cardiac investigations: These investigations help confirm the diagnosis, classify the severity, and assess the response to medical therapy. Non-invasive methods are useful in longitudinal follow-up of pulmonary hypertension.


Figure1 - Diagnostic algorithm for evaluation of PH


ECG: In established cases, right axis deviation, right ventricular hypertrophy and right atrial enlargement are seen (Figure 2).
Echocardiogram: A transthoracic echocardiogram can rule out a congenital heart lesion that can result in PH when unrepaired. It can also rule out left-heart defects (pulmonary vein stenosis, mitral inflow defects, left ventricular outflow defects and coarctation of the aorta) that can cause PH. When the spectral Doppler profile of the tricuspid or pulmonary regurgitant jet is of good quality, right ventricular systolic pressure can be determined non-invasively (Figure 3a). This is not only helpful for confirming the diagnosis of PH, but also in longitudinal follow-up. Right ventricular hypertrophy (Figure 3b) and dilation, as well as systolic and diastolic function can be assessed non-invasively. Three-dimensional echocardiography is a useful tool to assess right ventricular volumes. Left ventricular systolic and diastolic function can also be assessed.

ECG in PH


Cardiac Magnetic Resonance Imaging: CMR is the gold standard with respect to assessment of right ventricular volumes and mass. While not as readily available or inexpensive as an echocardiogram, it might be valuable in the longitudinal follow-up of the right ventricle. In the setting of congenital heart disease, it is also useful in defining anatomy, especially in the setting of repaired heart disease wherein echocardiographic imaging windows might be suboptimal. It is useful in assessing differential flow to lung segments, as well as in assessing pulmonary thrombi.
Computed tomography: A CT Scan of the chest can be obtained in a short duration of time, and might obviate the need for anesthesia for imaging. Its value is primarily in the diagnosis of pulmonary thromboembolism, as well as in the differentiation of pulmonary veno-occlusive disease from pulmonary capillary hemangiomatosis.

Echocardiography in PH


Cardiac Catheterization: Catheterization is the gold standard of diagnosis of PH. The mPAP as well as the PVRi can be assessed invasively. In infants and young children, where one is reasonably certain about the diagnosis of PH on the basis of non-invasive imaging, cardiac catheterization may not be done to avoid the morbidity of the procedure. In the setting of congenital heart disease, catheterization is valuable in assessing hemodynamics. The main utility of catheterization lies in our ability to carry out acute vasoreactivity testing (AVT) in the laboratory. The vasodilator agents used are oxygen, inhaled nitric oxide, and inhaled or intravenous prostacyclin analogues. This predicts the prognosis with the use of pulmonary vasodilators in the outpatient setting. The response to AVT also helps in determining operability in the setting of unrepaired congenital shunt lesions. Cardiac catheterization in patients with PH carries a significant risk of morbidity (acute hypertensive crises) and mortality, and should only be performed in centers that have experience with the management of PH.
Endurance testing: Both the 6-minute walk test and bicycle / treadmill ergometry are useful in the longitudinal follow-up of patients with PH.

Genetic testing: In the setting of a positive family history of PAH, genetic testing may be offered. BMPR2 has been identified as the primary pulmonary hypertension gene in the setting of HPAH. Genetic counseling in cases with a positive genotype is challenging given the incomplete penetrance of this gene, and the possibility that a “second hit” explains the association of a positive genotype with the development of PH.

References

Contributor Information and Disclosures

Rajesh Shenoy
MD, DCH, DNB, FAAP,
FACC Icahn School of Medicine at
Mount Sinai 1 Gustave Levy Place,
Box 1201 New York, NY 10029


First Created : 3/18/2016

References

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