The OPTICA Study - The Optimised Computed Tomography Pulmonary Angiography (CTPA) in Pregnancy, Quality and Safety Study

The OPTICA Study - A Prospective Study Assessing the Quality and Safety of an Optimised CTPA Protocol in Pregnancy

A prospective multicentre study aiming to validate the clinical utility and safety of an optimised low-dose computed-tomography pulmonary angiogram (CTPA) protocol for suspected pulmonary embolism in pregnancy

The OPTICA study is the first prospective study of a low-dose CTPA protocol for the pregnant population. It will define the achievable dose, image quality and safety of this protocol and provide an evidence base upon which modern CTPA protocols can be appropriately compared to scintigraphy for this population.

Pregnant women undergoing the specified low-dose CTPA protocol for suspected pulmonary embolism (PE), agreed across study sites with equivalent computed-tomography (CT) capabilities, will be included. Independent review of CTPAs by two radiology consultants, image data analysis and 3-month patient follow up will be performed.

The diagnostic algorithm employs chest-x-ray and lower limb Doppler if lower limb symptoms are present, followed by CTPA in cases where advanced imaging is required. D-dimer is permitted within the diagnostic algorithm for patients recruited after implementation of the updated 2019 "European Society of Cardiology guidelines for diagnosis and management of acute pulmonary embolism".

Inclusion Criteria:

1. Pregnant patients with a suspected pulmonary embolism
2. Age≥18 years

Exclusion Criteria:

1. Age < 18 years
2. Ultrasound proof of symptomatic proximal deep vein thrombosis
3. Contraindication to helical CT because of allergy to intravenous iodinated contrast or renal insufficiency (creatinine clearance <30 ml/min)
4. Treatment with full-dose therapeutic low molecular weight heparin or unfractionated heparin initiated 24 h or more prior to eligibility assessment
5. Treatment with vitamin K antagonists (coumarin derivates i.e. warfarin)
6. Unable or unwilling to consent
7. Unable to part-take in follow-up
8. Life expectancy <3 months