An audit of the clinical and sub-clinical changes in the first year following an acute deep vein thrombosis.

BACKGROUND: An audit of 100 proximal (above knee) deep vein thromboses (DVT) was carried out to document the dynamic status of the condition during the first year.

METHODS: Duplex ultrasound was used to diagnose the presence of an acute deep vein thrombosis in a consecutive series of patients. Follow-up bilateral ultrasound scans were performed at one week, one month, six months and at one year and clot retraction, lysis or extension were recorded. The patients' treatment regime and symptoms were also recorded at each follow-up examination.

RESULTS: There were 100 proximal DVT's from 89 patients (11 bilateral thromboses). The patient population included those with a previous history of DVT or in the end stages of a major illness and those with reversible risk factors. The mortality rate over the one-year period was 14 percent, most of the deaths occurring in the first month. The majority of deaths occurred as a result of an underlying primary disease (e.g. cancer) and 3 percent died from a pulmonary embolism. All patients were treated initially with either intravenous (IV) heparin or subcutaneous low molecular weight (SCLMW) heparin. Following heparin all patients were treated with warfarin. The duration of anticoagulant therapy varied with most physicians treating the patient for six months. Symptomatic and asymptomatic events (pulmonary emboli, extension of thrombi, new DVT's) were recorded in the follow-up period especially in the initial and late phase.

CONCLUSIONS: The audit concluded that the diagnosis and treatment of DVT continues to be a major clinical problem with uncertainty as to the type and length of treatment required. The mobility of the patient was not considered in the choice of initial heparin treatment. Anticoagulants were generally continued for a period of up to six months regardless of the patient's risk factors. Little consideration was given to asymptomatic events with physicians still depending on unreliable clinical symptoms to determine if recurrences had occurred. Generally, no consideration was given to the long-term consequences of a post-thrombotic limb at the initial stage of treatment of a DVT.