After myocardial infarction (MI) and cerebrovascular accidents (CVA), PE and Venous thromboembolism (VTE) are the third most common causes of cardiovascular death. PE is still a leading cause of avoidable in-hospital death. Due to its influence of the right side of the heart, it also has a high mortality rate. As a result, determining prognostic indicators is crucial in predicting the outcome and the mortality rate [10].
The diagnosis of massive PE is dependent on the presence of systemic arterial hypotension (systolic blood pressure less than 90 mm Hg). As a result, structurally large PE seen on CTPA in a patient who is hemodynamically stable is not considered massive PE and does not carry the same risk or mortality [11, 12].
We used ECG—gating throughout the cardiac cycle for RV cine evaluation to enable us to assess the wall motion, RV volume and RV function. MPA > 29 mm has been traditionally used as a threshold measurement above which PA hypertension is suggested [13,14,15,16].
In our study, patients with MPA diameter > 29 mm were considered abnormal. We calculated the RV/LV ratio by dividing the right and left ventricular diameters in the axial images at the level showing AV valves. We considered the ratio to be abnormal if > 1 as suggested by previous investigators [17].
In our study, 36 (60%) PE patients were admitted to the ICU, with 24 (40%) of them dying within a 30-day follow up period. In the study by Osman and Abdeldayem, 26.7% of PE patients needed ICU admission and 13.3% died [17].
MPA was considered dilated when diameter > 29 mm. We found a significant correlation between ICU admission and MPA diameter detected by CT with a p value of < 0.031. Significant correlation was also observed between ICU admission and RV/LV ratio > 1 detected by CTPA with a p value of 0.000. A study by Kaminetzky and colleagues reported no significant difference in clinical outcome in presence or absence of right heart strain with a p value > 0.05 [18].
Statistical significance between ICU admission and both left-sided septal deviation and contrast reflux into the IVC/distal hepatic veins was found with p values of 0.005 and 0.028 respectively which was in agreement with previous investigators [19]. Our findings were contrasted by the previously published results which showed that septal deviation and contrast reflux into IVC/distal hepatic vessels did not correlate with the severity of PE [17, 20, 21].
In our study, we correlated the 30-days mortality to different measurements obtained by CTPA. There was a statistically significant correlation between MPA diameter > 29 mm detected by CTPA and 30-day mortality with p value of < 0.001. Our findings were in contrast to those by Ghaye et al. who reported no significant correlation between PA dilatation detected by CTPA and mortality with a p value of 0.195 [22].
In our series, RV/LV ratio > 1 showed a significant correlation to 30-day mortality with a p value of < 0.001 which was similarly reported by two studies with p values of 0.01 and 0.04 respectively [22, 23]. Significant correlation was also found between 30-day mortality and left sided septal deviation with a p value of 0.015. This was contrasted to the data published by Collomb et al. and Araoz et al. who did not find correlation between PE severity and septal deviation [20, 21]. Another study reported that septal deviation was the least sensitive cardiac sign in PE severity assessment [17]. No significant correlation between reflux into IVC/distal hepatic veins and 30-day mortality was found in our series with a p value of 0.070 which was in agreement with previous investigators [17, 20].
Qanadli score gained attention as a prominent scoring system for embolic burden in PE patients. However, the relationship between this burden score and outcome in patients are still controversial [9, 24]. We found Qanadli score was highly correlated to both ICU admission and 30-day mortality in our population with a p value < 0.001.
Mean value for embolic burden in our study was 20.7 compared to 10 in the study by Wu et al. and 32 in Van der Meer et al. [23, 25]. We also studied the correlation between different radiological measurements obtained by CTPA and Qanadli score. Significant correlation was observed between embolic burden using Qanadli score and RV diameter, LV diameter and RV/LV ratio > 1 with p values of 0.014, 0.008 and 0.001 respectively which was similarly reported by Ghaye et al. [22].
Our results have shown that incorporating CTPA measurements in patients’ reports can guide the treating physician in the management process, predicting the patients with high mortality risk or who would need ICU admission for close monitoring or thrombolysis sparing the from the patients from delay in management or additional investigations such as ECHO [26].
The strength of our study is that data were gathered based on our inclusion and exclusion criteria, all patients underwent ECG gated CTPA and ECHO, and all clinical outcomes and imaging data were blindly assessed for treatment and outcome.
The limitation of our study is that we only investigated the most commonly utilized radiological parameters and cut off values because they were the easiest to implement. Another limitation is the small sample size. More studies with larger sample size are needed in the future to confirm and further documents our results.