In addition, pressure gradient-volume diagrams derived from 3-D echocardiography data can be used to reliably estimate RV stroke work in patients with PH [29]. Populations including those with a known genetic mutation associated with PAH, first degree relative with PAH, scleroderma spectrum, congenital heart disease, and portal hypertension before liver transplant are at high risk of developing PAH and may benefit from screening with echocardiography [30]. Patients with a high echocardiographic probability for PH have poorer postsurgical outcomes; thus, PH echocardiographic probability can also be used to risk stratify patients with risk factors for PH before a procedure/surgery [27,31]. As mentioned above, transthoracic Doppler echocardiography will not reliably detect mild, asymptomatic PH. Further evaluation with additional noninvasive examinations including CT and MRI may be obtained if there is persistent, high clinical suspicion for PH. RHC is also useful for further evaluation [10,24]. V/Q Scan Lung There are no data to suggest ventilation-perfusion (V/Q) scintigraphy as an initial test in the workup of suspected PH. However, current guidelines recommend V/Q scintigraphy of the lungs in all patients with unexplained PH to assess for CTEPH [24]. Identification of CTEPH is important because it allows for potentially curative surgical therapy [33]. V/Q scintigraphy typically shows mismatched wedge-shaped, segmental defects in the setting of CTEPH that can normalize after surgical treatment [34]. The high sensitivity and specificity of V/Q scintigraphy is useful for CTEPH detection [34]. A recent study by Mehari et al [35] comparing V/Q scintigraphy and multidetector CT pulmonary angiography (CTPA) for CTEPH detection found that V/Q scintigraphy had excellent sensitivity (90%) and good specificity (75%), whereas CTPA suffered from poor sensitivity (37%), although it had excellent specificity (100%).
Suspected Pulmonary Hypertension. In addition, pressure gradient-volume diagrams derived from 3-D echocardiography data can be used to reliably estimate RV stroke work in patients with PH [29]. Populations including those with a known genetic mutation associated with PAH, first degree relative with PAH, scleroderma spectrum, congenital heart disease, and portal hypertension before liver transplant are at high risk of developing PAH and may benefit from screening with echocardiography [30]. Patients with a high echocardiographic probability for PH have poorer postsurgical outcomes; thus, PH echocardiographic probability can also be used to risk stratify patients with risk factors for PH before a procedure/surgery [27,31]. As mentioned above, transthoracic Doppler echocardiography will not reliably detect mild, asymptomatic PH. Further evaluation with additional noninvasive examinations including CT and MRI may be obtained if there is persistent, high clinical suspicion for PH. RHC is also useful for further evaluation [10,24]. V/Q Scan Lung There are no data to suggest ventilation-perfusion (V/Q) scintigraphy as an initial test in the workup of suspected PH. However, current guidelines recommend V/Q scintigraphy of the lungs in all patients with unexplained PH to assess for CTEPH [24]. Identification of CTEPH is important because it allows for potentially curative surgical therapy [33]. V/Q scintigraphy typically shows mismatched wedge-shaped, segmental defects in the setting of CTEPH that can normalize after surgical treatment [34]. The high sensitivity and specificity of V/Q scintigraphy is useful for CTEPH detection [34]. A recent study by Mehari et al [35] comparing V/Q scintigraphy and multidetector CT pulmonary angiography (CTPA) for CTEPH detection found that V/Q scintigraphy had excellent sensitivity (90%) and good specificity (75%), whereas CTPA suffered from poor sensitivity (37%), although it had excellent specificity (100%).