SPC365

A new ratio with PaO2/FiO2 and pulmonary arterial systolic pressure in the prognosis of intermediate high risk pulmonary embolism

Session: Posters - F. Valvular, Myocardial, Pericardial, Pulmonary, Congenital Heart Disease
Speaker: Maria Inês Fiúza Pires

Congress: CPC 2021
Topic: F. Valvular, Myocardial, Pericardial, Pulmonary, Congenital Heart Disease
Theme: 21. Pulmonary Circulation, Pulmonary Embolism, Right Heart Failure
Subtheme: 21.2 Pulmonary Circulation, Pulmonary Embolism, Right Heart Failure – Epidemiology, Prognosis, Outcome
Session Type: Posters
FP Number: ---
Authors: Inês Pires; João Miguel Santos; Joana Correia; Vanda Neto; Luísa Gonçalves; José Costa Cabral; Inês Almeida

<p style="text-align:justify"><span style="font-size:11pt"><span style="font-family:Calibri,sans-serif">Background: Intermediate high (IH) risk pulmonary embolism (PE) defines a category of patients (P) at increased risk of haemodynamic decompensation. Therefore, it is important to develop tools to identify P who will have an unfavourable outcome. The ratio between arterial oxygen partial pressure (PaO2) to fractional inspired oxygen (FiO2) &ndash; P/F ratio - is associated with in-hospital mortality (IHM) in PE. Pulmonary arterial systolic pressure (PASP) is another prognostic factor, related with right ventricular (RV) pressure overload. This study evaluates the usefulness of a new ratio with P/F divided by PASP (P/F:PASP), reflecting both severity of respiratory failure and pressure overload, in the prognosis of P with IH risk PE.</span></span></p>

<p style="text-align:justify"><span style="font-size:11pt"><span style="font-family:Calibri,sans-serif">Methods: All P admitted for IH risk PE in an Intensive Cardiac Care Unit (ICCU) for 10 years were included. P/F ratio was calculated with admission blood gas analysis and PASP was obtained with echocardiography at admission in ICCU. P/F:PASP ratio was considered low if inferior to its median. Need for fibrinolysis and IHM were assessed. Follow-up (FU) of 2 years for all-cause mortality was done. Statistical analysis used chi-square and Mann-Whitney U tests, binary logistic regressions and Kaplan-Meier curves.</span></span></p>

<p style="text-align:justify"><span style="font-size:11pt"><span style="font-family:Calibri,sans-serif">Results: 101 P were studied (mean age 63&plusmn;17 years; 35.6% male). Mean P/F, PASP and P/F:PSAP were 264&plusmn;68, 45&plusmn;15 mmHg and 6.7&plusmn;3.3, respectively. P/F:PASP was considered low if inferior to 5.9.</span></span></p>

<p style="text-align:justify"><span style="font-size:11pt"><span style="font-family:Calibri,sans-serif">There was no difference in age, gender, comorbidities or Pulmonary Embolism Severity Index (PESI) between P with low or high P/F:PASP. However, low P/F:PASP ratio was associated with tachypnea at admission (p=0.034), higher BNP level (p= 0.011), right precordial leads T-wave inversion (p=0.029), presence of echocardiographic right ventricle dilation (p=0.002) and lower TAPSE (p=0.002).</span></span></p>

<p style="text-align:justify"><span style="font-size:11pt"><span style="font-family:Calibri,sans-serif">Among P who underwent fibrinolysis, 60.4% had low P/F:PASP and 39.6% had high P/F:PASP ratio (&chi;<sup>2</sup>=3.32, p=0.05). P/F:PASP ratio was a predictor of fibrinolysis (OR 0.83, 95%CI 0.72-0.96, p=0.011), with lower ratio increasing the probability of fibrinolysis. This result was independent from PESI (OR 0.84, 95%CI 0.72-0.97, p=0.015). P/F:PASP ratio was also a predictor of IHM (OR 0.62, 95%CI 0.38-1, p=0.05).</span></span></p>

<p style="text-align:justify"><span style="font-size:11pt"><span style="font-family:Calibri,sans-serif">During FU, there was no difference in mortality between P with low or high P/F:PASP ratio (8.5% vs. 10.4%, respectively; <span style="background-color:white"><span style="color:#222222">Kaplan-</span></span><span style="background-color:white">Meier </span><span style="background-color:white">&chi;</span><sup><span style="background-color:white">2</span></sup><span style="background-color:white">=0.095; p=0.758).</span></span></span></p>

<p style="text-align:justify"><span style="font-size:11pt"><span style="font-family:Calibri,sans-serif">Conclusions: In IH risk PE, low P/F:PASP ratio was associated with analytical, electrocardiographic and echocardiographic risk features. In this study, P/F:PASP ratio was a predictor of short term prognosis, allowing identification of P at higher risk of fibrinolysis and IHM, but it was not useful for long term prognosis, as 2-year mortality was similar between the groups. Therefore, this ratio, as a measure of both respiratory failure and pressure overload, might allow refinement in risk stratification of P with IH risk PE. </span></span></p>