[Clot burden score in the evaluation of right ventricular dysfunction in acute pulmonary embolism: quantifying the cause and clarifying the consequences].

BACKGROUND

Pulmonary angiography by computed tomography (CT) is the method of choice for the detection of acute pulmonary embolism (PE). Studies have shown that the severity of PE can be estimated by clot burden scores.

OBJECTIVE

To evaluate the correlation between an angiographic clot burden score (Qanadli score - QS) and parameters of right ventricular dysfunction (RVD) in patients admitted for PE.

METHODS

We performed a retrospective study of 107 patients (60% female) admitted to an intensive care unit for PE (intermediate/high risk) between January 1, 2007 and September 30, 2011. Images from 16-slice multidetector CT angiography were reviewed in 102 patients and the QS calculated. Based on a cut-off of 18 points established by ROC curve analysis, two groups were formed (A<18 points vs. B ≥18 points) and the clinical, laboratory, ECG, echocardiographic and CT angiography parameters were compared. The statistical analysis was performed using SPSS.

RESULTS

The overall mean age was 61.4 years. With regard to symptoms at admission, there was a greater prevalence in group B of fatigue, chest pain and syncope (p=0.017), with higher Geneva and Wells scores and shock index. In terms of ECG parameters, heart rate and percentage of right bundle branch block, T-wave inversion (V(1)-V(3)) and S(1)Q(3)T(3) pattern (p=0.034) were higher in group B, as was the ECG score (p=0.009). Laboratory tests revealed that group B had higher troponin and d-dimers, with lower creatinine clearance by the MDRD formula (p=0.020) and PO(2)/FiO(2) ratio. Echocardiography showed higher pulmonary artery systolic pressure in group B, and CT angiography revealed larger right ventricular (RV) diameters and higher RV/LV ratio (p=0.002), and greater superior vena cava, azygos vein and coronary sinus diameters in this group. Pulmonary artery (PA) diameter and the PA/aorta ratio were similar. Interventricular septal bowing and reflux of contrast into the inferior vena cava (p=0.001) were greater in group B, and QS>18 was an independent predictor of RVD (RV/LV ratio>1) (OR: 10.85; p<0.001) (area under the curve on ROC analysis: 0.79; p<0.001). The percentage of patients receiving fibrinolytic treatment was higher in group B (p=0.045), and in-hospital mortality was similar in both groups (overall 4.9%).

CONCLUSIONS

QS >18 points proved to be an independent predictor of RVD in PE, and correlated linearly with variables associated with higher morbidity and mortality.