Prognostic significance of the lung scintigraphy scan result and corresponding chest X-ray in patients with suspected pulmonary embolism

Aim
:  To  determine  whether  the  survival  of  patients  with  suspected  acute pulmonary embolism (PE) relates to radiological probability of acute PE assessed using lung scintigraphy scans (LSS).
Methods
:  Lung  scintigraphy  scan  results  from  a  venous  thromboembolism database  were  categorised  as  high,  indeterminate  or  low  probability  using  the modified PIOPED criteria and corresponding chest X-rays (CXRs) as normal or abnormal. Mortality data on these cases were obtained from the General Register Office for Scotland, and survival was analysed using the Kaplan-Meier method.
Results
:  Of  the  1,818  LSS  analysed,  941  (51.8%)  were  normal,  532  (29.3%) indeterminate and 345 (19.0%) high probability. After an adjustment for age and gender, no significant survival difference was found between patients with normal and high probability LSS (p=0.182). However, patients with indeterminate LSS had significantly  lower  survival  than  patients  in  the  other  groups.  This  difference persisted after adjustment for CXR result.
Conclusions
:  Indeterminate  LSS  results  are  associated  with  a  poor  prognosis.   Careful follow-up of patients with inderminate LSS would appear to be justified.