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.