Table 3.

Characteristics of Patients in the Negative Cohort with Suspected Recurrent Venous Thromboembolism during Follow-up^*

Patient Study Number	Time to Suspected Event (Days after Study Entry)	Warfarin/INR at Time of Suspected Event	New Risk Factor for Venous Thromboembolism	Diagnostic Test Results†	Additional Anticoagulant Therapy and Outcome‡
Suspected DVT
R147	7	No warfarin	Hospitalization	US normal	None
R086	12	No warfarin	No new risk factor	US inconclusive	None
R100	28	No warfarin	No new risk factor	IPG normal	None
R108	31	Warfarin/3.6	Uterine ablation procedure	US inconclusive	None
R152	38	No warfarin	No new risk factor	US normal	None
R057	52	Warfarin/no INR	No new risk factor	US inconclusive	None
R062	61	Warfarin/3.5	Nonadherence	No testing done	None
R025	65	Warfarin/1.5	No new risk factor	US inconclusive	None
R042	79	Warfarin/1.6	Fall on knees	US inconclusive	LMWH therapy while restoring INR to a value >2.0
Suspected PE
R123	16	No warfarin/1.2	Warfarin therapy withdrawn 72 h before study entry because of bleeding	Lung scan; no new defects	None
R228	43	No warfarin	Warfarin therapy discontinued 7 days after study entry	High-probability lung scan	LMWH and warfarin therapy

^*DVT = deep venous thrombosis; INR = international normalized ratio; IPG = impedance plethysmography; LMWH = low-molecular-weight heparin; PE = pulmonary embolism; US = ultrasonography.

^†Inconclusive = abnormal with persistent noncompressibility in the same venous segments as the most recent previous ultrasonography report.

^‡None = no heparin or LMWH therapy was given, and there were no additional symptomatic thromboembolic events at 3 months.