Does saddle embolism influence short-term prognosis in patients with acute pulmonary embolism?

Background: In some patients with acute pulmonary embolism (APE) thrombi may lodge at the levels of the bifurcation of pulmonary trunk and extend into both main pulmonary arteries, forming so-called saddle embolism (SE).

Aim: To assess the incidence of SE and whether it is associated with an increased risk of complicated clinical course.

Methods: We studied 150 consecutive patients (94 females, 56 males) aged 63.6+/-16.7 years with APE confirmed with contrast enhanced spiral computed tomography or transesophageal echocardiography.

Results: SE was detected in 22 (14.7%) patients. Mean age (SE vs N-SE) was 64.3+/-17.4 vs 63.5+/-16.6 years, heart rate 100.8+/-14.1 beats/min vs 97.8+/-21.1 beats/min, systolic blood pressure 126.2+/-20.1 vs 127.1+/-23.3 mmHg and blood pulsoximetry 92 (68-98) vs 91 (30-98) % (all differences NS). In patients with SE, echocardiographic signs of the right ventricular overload, defined as right to left ventricular end - diastolic ratio >0.6 with right ventricular hypokinesia and/or maximal tricuspid peak systolic gradient >30 mmHg with shortened acceleration time of pulmonary ejection <80 ms, were more frequent (77.3% vs 51.6%, p=0.04), as was the mid-systolic deceleration of pulmonary ejection velocity (77.3% vs 49.2%, p=0.04). Mortality and complicated clinical course rates were similar in patients with SE or N-SE (mortality: 4.5% vs 13.3%, NS, and complicated clinical course: 34.4% vs 25.0%, NS).

Conclusions: Saddle pulmonary embolism is frequent, especially in patients with echocardiographic signs of impaired pulmonary ejection pattern. Saddle embolism does not indicate unfavourable clinical outcome and probably should not influence treatment selection.