Non-invasive assessment of pulmonary hypertension: Doppler–echocardiography
Introduction
Pulmonary hypertension (PH) is a clinical condition characterised by elevated pulmonary artery pressure (PAP) and vascular resistance. PH is defined as mean pulmonary artery pressure (MPAP) exceeding 25 mm Hg at rest, or 30 mm Hg during exercise.
Echo–Doppler assessment of PH includes three different issues: detection of elevated PAP values, functional evaluation of the right ventricle, and differential diagnosis to detect underlying conditions such as congenital heart disease or left heart disease. The present review highlights the scientific status of echocardiography in the first two issues.
Section snippets
Detection of pulmonary hypertension
The sensitivity and specificity of Echo–Doppler evaluation in diagnosing PH are strongly dependent on the threshold value used as a cut-off point for establishing the presence of PH and PH grades of severity. Unfortunately, several conditions limit the capability to detect and measure the velocity of the tricuspid regurgitant jet, such as air trapping, expansion of the thoracic cage and alterations in the position of the heart. Moreover, both the positive and the negative predictive values of
Right atrial pressure estimation
Elevated RAP is a manifestation of right ventricular failure usually due to high right ventricular diastolic pressure. RAP has been demonstrated as a strong predictor of survival in both baseline conditions and during follow-up therapy of patients with PH. Nevertheless, despite several attempts made to obtain an accurate estimation of RAP, attention has been focused mainly on patients with chronic heart failure (CHF) due to both ischaemic and idiopathic cardiomyopathy. Thus, application of
Normal values and clinical implications
Cardiac catheterisation is currently used as the gold standard technique to firmly establish haemodynamic status, although there is no clear consensus as to what value of PAP is needed for PH diagnosis [3], [4], [10], [11], [12], [13].
The Third World Symposium on Pulmonary Hypertension held in Venice in 2003 defined mild PH as a resting Doppler-estimated PASP between 36 and 50 mm Hg, which corresponds to a tricuspid regurgitant velocity of 2.8–3.4 m/s, assuming a fixed 5 mm Hg RAP [14].
Doppler
Morphological evaluation of right side chambers
Morphological description comprises evaluation of right side chambers dimensions, including determination of pulmonary artery dimension, detection of right ventricular hypertrophy, and description of pericardial effusion. Right ventricular hypertrophy is mostly the consequence of a chronically increased afterload and it is generally assessed by measuring the end-diastolic thickness of the free wall; a value above 5 mm is strongly associated with a chronic increased afterload [20], [21], [22].
Functional evaluation of the right ventricle
The pulmonary circulation is a low pressure and low resistance highly compliant system, able to accommodate flow rates ranging from resting conditions to strenuous exercise, with minimal increases in pulmonary pressures. This is possible because of the favourable reserve characteristic of the pulmonary circulation, reflecting passive distension of the vascular bed and recruitment of additional vessels. The primary function of the right ventricle is to provide sustained low-pressure perfusion
Conclusion
Evaluation of right ventricle performance in PH patients is difficult and, as a consequence, needs to be done by an experienced cardiologist and cannot be carried out by sonographers without specific experience.
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Percutaneous CT guided lung biopsy in patients with pulmonary hypertension: Assessment of complications
2016, European Journal of RadiologyCitation Excerpt :Second, all patients included in our study had cardiac ultrasound within 6 months, which estimated pulmonary arterial pressures using tricuspid regurgitate jet method [21]. Although there still might be an on-going debate in the scientific community regarding the accuracy of cardiac ultrasound in diagnosing PHTN, echocardiography has been accepted as a non-invasive and readily available modality for identification of patients with PHTN [13,21]. Some of patients in our study underwent an additional right cardiac angiography prior to PTNAB, which confirmed the diagnosis of PHTN.
Changes in Right Ventricular Function with Exercise in Healthy Subjects: Optimal Parameters and Effects of Gender and Age
2015, Journal of the American Society of EchocardiographyCitation Excerpt :In normal subjects, the increase in cardiac output with exercise has little effect on PAP and is likely due to the distension and recruitment of pulmonary vasculature. PAP increases with age and body mass index and is higher in men, with a percentage of older and obese subjects with PAP > 40 mm Hg (currently considered elevated PAP).37,38 Bossone et al.39 sought to investigate the upper limits of PAP change with exercise, but that study included only young active men.
Accuracy of Doppler echocardiographic estimates of pulmonary artery pressures in a canine model of pulmonary hypertension
2015, Journal of Veterinary CardiologyOpposite behavior of plasma levels surfactant protein type B and receptor for advanced glycation end products in pulmonary sarcoidosis
2013, Respiratory MedicineCitation Excerpt :The tricuspidal annular plane systolic excursion (TAPSE) was measured in the M-mode by placing the cursor through the lateral tricuspid annulus in the apical four-chamber view. Pulmonary systolic artery pressure (PASP) was indirectly obtained by adding the mean right atrial pressure to the peak systolic pressure gradient of tricuspid regurgitant flow [24]. Standard echocardiographic views were analyzed by a single expert physician blind to the results of subjects' clinical characteristics, and they were obtained according to the recommendations by the American Society of Echocardiography [25].