Transthoracic echocardiography: a surrogate tool for predicting pulmonary hypertension using pulmonary artery to aorta ratio

Background Owing to the nonspecific and subtle nature of physical signs and symptoms of pulmonary hypertension (PH) in early stages, treatment is usually delayed despite advancement over the past decade. Use of transthoracic echocardiography (TTE) as the initial noninvasive modality in the screening and evaluation of PH can provide key information about the etiology and the prognosis of PH, thereby avoiding the complications associated with the invasive methods. The aim of this study was to determine the usefulness of main pulmonary artery (mPA) and ascending aorta (AscAo) ratio using TTE. Patients and methods In this prospective observational study, 30 adult patients undergoing elective coronary artery bypass grafting surgery were enrolled. Postanesthetic induction mPA and AscAo transverse diameters were measured using TTE. The mean pulmonary arterial pressures (mPAPs) were recorded using a direct pulmonary artery puncture after sternotomy. Correlations were established using the Pearson correlation coefficient. Sensitivity, specificity, positive predictive value, and negative predictive value were calculated. Results mPA : AscAo ratio demonstrated significant linear correlation with mPAP (i.e. r=0.553, P=0.00152). Sensitivity, specificity, positive predictive value, negative predictive value were 80, 100, 80, and 100%, respectively, for an mPAP of up to 25 mmHg. Conclusion TTE-guided measurement of mPA : AscAo ratio can be used as a simple and easily reproducible noninvasive method in predicting PH not only in cardiac but also in other noncardiac settings.