Data collection
A manual review of patient charts was then undertaken to confirm the
diagnosis and to obtain preoperative, perioperative, and postoperative
variables and outcomes. At hospital or ICU admission, we collected the
following information: demographics, presence of venous-thromboembolic
risk factors; Simplified Acute Physiology Score (SAPS)
II9 and Sequential Organ Failure Assessment (SOFA)
score10.
During the pre-ECMO period, the inotrope score11,
defined as dobutamine dose (γ/kg/min) + [norepinephrine dose
(γ/kg/min) + epinephrine dose (γ/kg/min)] × 100; cardiopulmonary
arrest with its related “low-flow” and “no-flow” situations; and
troponin level and blood gas analyses were noted. The echocardiography
variables which includes; left ventricular ejection fraction (LVEF),
RV/LV dimension ratio and visualization of a pulmonary arterial thrombus
were also recorded before ECMO insertion. RV dysfunction (none, mild,
moderate, or severe) was recorded according to a preoperative and
postoperative transthoracic echocardiogram by an independent
cardiologist, who both quantitatively and qualitatively assessed RV
function.
The pulmonary angiography was independently reviewed for quantification
of pulmonary emboli by one observer who was blinded to the clinical
course. We applied an embolic burden scoring system in our study:
observer scored main, lobar, right interlobar and segmental pulmonary
arteries for the presence of emboli and also graded whether emboli were
occlusive12.