Tricuspid Regurgitation Peak Gradient /Tricuspid Annular Plane Systolic Excursion: A Novel Parameter for Risk Stratification in Normotensive Patients with Acute Pulmonary Embolism Using 2D Transthoracic Echocardiography

Background: Pulmonary embolism [PE] results from the occlusion of the pulmonary artery or its branches by a thrombus that has dislodged from a different anatomical location, thereby disrupting normal blood flow in the pulmonary circulation.
Aim of the work:  This work was designed to evaluate the prognostic significance of a novel echocardiographic parameter, Tricuspid regurgitation peak gradient /tricuspid annular plane systolic excursion [TRPG/ TAPSE] in predicting in-hospital mortality among acute PE [APE] patients who are hemodynamically stable during their hospital stay.
Patients and Methods: Sixty patients [n=60] with a definitive diagnosis of APE were recruited in this prospective study executed at Al Azhar University Hospital and Mabarat El Asafra Hospital. Patients were divided into two groups: group [1] included patients who didn’t achieve clinical endpoint and group [2] included patients who achieved clinical endpoint. The clinical endpoint was defined as the occurrence of at least one of the following: [1] need for cardiopulmonary resuscitation, [2] systolic blood pressure <90 mmHg for at least 15 minutes with signs of end-organ hypoperfusion, [3] need for intravenous catecholamines in vasopressor doses.  
Results: Receiver operating characteristic [ROC] analysis revealed that the Area under Curve [AUC] for TAPSE in predicting the clinical endpoint in APE individuals was 0.834. TAPSE's cut-off value was determined as <13 mm, with an AUC of 0.834, 77.4% sensitivity, 85.7% specificity, 84.4% PPV, and 79.1% NPV. The cut-off value of TRPG as > 47 mmHg with AUC of 0.540, 54.7% sensitivity, 71.4% specificity, 65.7% PPV and 61.2% NPV. The TRPG/TAPSE ratio, expressed in mmHg/mm parameter was chosen as the next step for risk stratification. The optimal value of 4.8 mmHg/mm demonstrated 94.3% sensitivity, 100% specificity, 100% PPV and 94.6% NPV.
Conclusion: TRPG/TAPSE, a key echocardiographic parameter, is strongly correlated with clinical deterioration of non-high risk pulmonary embolism and hold potential for risk stratification and forecasting clinical deterioration of   hemodynamically stable patients with APE.