Imaging in pulmonary hypertension: Focus on the role of echocardiography

Abstract

Patients with pulmonary hypertension must be evaluated using a multimodality approach to ensure a correct diagnosis and basal evaluation as well as a prognostic assessment. Beyond the assessment of pulmonary pressures, the echocardiographical examination allows the evaluation of right ventricular adaptation to elevated afterload. Numbers of variables are commonly used in the assessment of the pulmonary hypertension patient in order to detect changes in right heart geometry, right-to-left interaction and right ventricular dysfunction. Whereas an isolated change in one echocardiographical variable is not meaningful, multiple echocardiographical variable modifications together provide accurate information. In this review, we will link pulmonary hypertension pathophysiological changes with echocardiographical indices and describe the clinical implications of echocardiographical findings.

Right Atrial Evaluation in Patients With Pulmonary Hypertension

“…Right ventricular dilatation was identified as an RV end‐diastolic basal diameter of greater than 42 mm, and RV systolic dysfunction was diagnosed when the RV fractional area change was less than 35% 10 , 25 , 32 . All patients with pulmonary hypertension were divided into 3 subgroups based on the above criteria regarding RV structure and function: 1, normal RV dimension; 2, RV enlargement and preserved RV systolic function; and 3, RV enlargement and systolic dysfunction.…”

The Role of Echocardiography in the Evaluation of Pulmonary Arterial Hypertension

“…For IVC diameter ≥2.1 cm with <50% collapse on inspiration, RAP is assumed to be elevated to 15 mmHg. If there is an abnormality in only one of the parameters, a value of 8 mmHg is assigned . In such situations, it may be preferable to utilize another surrogate for RAP, such as the tricuspid E/E′ ratio (a value >6 is considered abnormal and indicates elevated RAP) or the pattern of hepatic vein flow (Fig.…”

Transesophageal Echocardiographic Approach to a Patient with Suspected Pulmonary Hypertension in the Intraoperative Period

“…39 Since the RV works against the low-pressure system of pulmonary vasculature, even when both LV and RV produce the same stroke volume, the thickness of RV wall is lesser than LV and the total mass of RV is only 1/5th to 1/6th of LV mass. 19,40 As the pulmonary pressure increases, the thickness of RV increases proportionately, causing RV hypertrophy to a point of compensation after which the further increase in pulmonary pressure causes RV dilatation. 2,[41][42][43] Similarly, the absence of an intermediate circumferential layer in RV when compared with LV makes the longitudinal movement a predominant contributor, while rotational movement contributes minimally to the ejection.…”

“…In case of absence of CVP monitor, it can be measured directly from the RA by inserting a needle with a pressure transducer attached to it. The measurement of RAP from the inferior vena cava (IVC) diameter and its collapsibility in the spontaneously breathing patient 19 are not validated in the mechanically ventilated patient. In the nonavailability of the above measures, the RAP can be estimated approximately by evaluation of TV inflow pattern in which the systolic filling fraction (systolic VTI/[systolic VTI + diastolic VTI]) < 0.55, where VTI is the velocity time integral and on hepatic flow pattern in which the ratio of systolic to diastolic flow velocity <1 (Fig.…”

“…2,[41][42][43] Similarly, the absence of an intermediate circumferential layer in RV when compared with LV makes the longitudinal movement a predominant contributor, while rotational movement contributes minimally to the ejection. 19 While assessing the RV, it can be assessed broadly into anatomic parameters and functional parameters.…”