The value of ventilation-perfusion imaging in pregnancy.

Pulmonary embolism (PE) is a major cause of maternal death during pregnancy. The aims of this retrospective study were to review 5 years experience of ventilation-perfusion (V/Q) imaging in pregnancy, to evaluate the effect of the V/Q scan report on the referring clinician's use of anticoagulants and to monitor the course and outcome of pregnancy. 82 patients (aged 17-44 years, gestation 6-40 weeks) underwent V/Q imaging for suspected PE, over a 5 year period. Modified PIOPED criteria were used to assess the probability of PE. 31 patients were shown to have normal scans (38%); 19 (23%) had low probability (LP) scans; 14 (17%) had intermediate probability (IP) scans and 18 (22%) had high probability (HP) scans for PE. Referring clinicians saw the reports and took action within 12 h. Anticoagulation was continued or started in 31 patients (all HP, 12 IP and 1 LP). Anticoagulation was considered unnecessary in 52 patients (all normal, 19 LP and 2 IP). None of the patients with normal or LP scans had documented PE during the follow-up period (median 25 months, range 3-60 months). No complications of anticoagulation were observed and no adverse outcome of pregnancy were reported. V/Q imaging is a valuable technique in the management of pregnant women suspected of having PE.