Meyer 1995.

Methods	Study design: randomised, multicentre pilot study. Method of randomisation: not stated. Concealment of allocation: sealed envelopes, not blinded for treatment allocation, blinded for outcome assessment. Exclusions post‐randomisation: none. Lost to follow‐up: none.
Participants	Country: France. Setting: hospital. No.: 60 participants: 29 LMWH, 31 UF heparin. Age: mean 60 (range 26 to 84) years LMWH, mean 61 (20 to 88) years UF heparin. Sex: LMWH 9 M/20 F, UF heparin 17 M/14 F Inclusion criteria: men and women > 18 years, weighing 45 to 90 kg and with onset of symptoms suggestive of acute PE within the 5 preceding days. Exclusion criteria: known pregnancy or breastfeeding, major surgical procedure or organ biopsy within the last 5 days, ischaemic cerebrovascular accident within the past 30 days or cerebral haemorrhage within the last 3 months, known haemorrhagic diathesis, active peptic ulcer, pre‐existing significant cardiorespiratory disease, known proliferative diabetic retinopathy, known allergy to heparin or contrast media, platelet count < 100 10⁹/L, chronic renal failure, chronic liver disease, treatment with UFH or LMWH at full dosage for more than 24 hours before randomisation, planned hospital stay < 10 days, oral anticoagulant therapy within 5 days before randomisation and any clinical condition which in the opinion of the physician in charge would not allow safe fulfilment of the protocol.
Interventions	Treatment: LMWH: fragmin at a fixed dose of 120 anti‐Xa IU/kg subcutaneously twice daily and without any laboratory adjustment. Control: UFH as a continuous intravenous infusion at an initial dosage of 500 IU/kg/24 hours and adjusted daily to maintain APTT between 2 to 3 times the control value. Treatment duration: 10 days Oral anticoagulation: acenocoumarol started on day 7 and continued for at least 3 months
Outcomes	Primary: incidence of PE recurrence within the first 10 days of treatment Secondary: pulmonary scintigraphic vascular obstruction score (PVOS), major bleeding
Notes	Follow‐up: 3 months
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Quote: "Treatment was randomly allocated". Comment: insufficient information to permit judgement.
Allocation concealment (selection bias)	Unclear risk	Quote: "Treatment was randomly allocated using sealed envelopes". Comment: although the use of assignment envelopes is described, it remains unclear whether envelopes were sequentially numbered and opaque.
Blinding of participants and personnel (performance bias) All outcomes	Low risk	Not blinded for treatment allocation. Comment: given the clinical outcomes of the study, review authors judged that the non‐blinding of the participants and staff was unlikely to have affected the outcomes.
Blinding of outcome assessment (detection bias) All outcomes	Low risk	Quote: "Open study. All angiograms were reviewed and scored blindly by 3 independent readers unaware of the treatment allocation and clinical events that occurred during the trial. Perfusion lung scans were reviewed and scored blindly by 2 independent readers according to the same procedure". Comment: review authors judged that the non‐blinding of the participants and staff was unlikely to have affected the outcomes. Furthermore, the blinding of outcome assessment was ensured.
Incomplete outcome data (attrition bias) All outcomes	Low risk	All data accounted for.
Selective reporting (reporting bias)	Low risk	Study reports data on all pre‐specified outcomes.
Other bias	Low risk	Study appears to be free from other sources of bias.