Management and outcomes of axial isolated distal deep vein thrombosis at North Shore Hospital, New Zealand: a retrospective audit.

BACKGROUND: It is standard of care to treat proximal vein deep vein thrombosis (DVT) for a minimum of 3 months. Conversely, management of isolated distal DVT (IDDVT) is controversial, with options including observation and repeat ultrasound scan within 1 week to detect and anticoagulate those with proximal propagation, or anticoagulation for periods of up to 3 months. AIM: The aim was to assess the rates of proximal propagation and venous thromboembolism (VTE) recurrence within 3 months of diagnosis of IDDVT, and to examine how the duration of treatment might influence this. METHODS: Study patients were identified by retrospective audit of data from the North Shore Hospital VTE database. All patients presenting with established axial vein distal DVT from July 2007 to June 2012 were included. A 6-week treatment duration cut-off was used to separate the treatment arms (<6 weeks vs 6 weeks vs >6 weeks), and Fisher's exact or Pearson's Chi-squared tests were used to assess between-group comparisons. RESULTS: Five hundred and seven patients were included in the study, mean age 59.7 years; 53% female. There were three cases of proximal propagation, all occurring in those receiving <6 weeks treatment. There were six VTE recurrences, three in the <6 week and three in the ≥6 week treatment groups respectively. Malignancy was the only significant predictor of VTE recurrence (P = 0.001). CONCLUSION: A 6-week duration of anticoagulation appears to be an effective and safe treatment for isolated axial distal DVT, with low rates of VTE recurrence and proximal propagation.

Management and outcomes of single subsegmental pulmonary embolus: a retrospective audit at North Shore Hospital, New Zealand.

BACKGROUND: It is unknown whether filling defects in subsegmental arteries on multidetector computed tomography pulmonary angiography correlate with clinically relevant subsegmental pulmonary embolism (PE) on pulmonary angiography. Current guidelines do not differentiate between PE in segmental and subsegmental vessels, and many patients receive at least 3 months anticoagulation. The strategy employed at North Shore Hospital in haemodynamically stable patients with single subsegmental PE is to perform bilateral lower leg compression ultrasound (CUS). Anticoagulation is withheld if CUS is negative; a bilateral CUS is repeated in 7-10 days. AIM: The aim of this retrospective audit was to ensure our current management strategy is safe. METHODS: All diagnoses of single subsegmental PE between June 2005 and June 2013 were included. The primary outcome was the rate of venous thromboembolism (VTE) recurrence within 3 months of single subsegmental PE diagnosis. Secondary outcomes were rates of major/minor bleeding and all-cause mortality. RESULTS: Thirty-two patients were included - 20 were treated with anticoagulation; 12 were managed with observation/serial bilateral lower limb CUS. None of the patients in either group had VTE recurrence by 3 months. No bleeding episodes were observed in the observation group; there was a 10% major bleeding rate (n = 2) in the treatment group. One death occurred in each group, neither of which was attributed to VTE. CONCLUSION: Withholding anticoagulation in patients with single subsegmental PE and negative serial bilateral CUS appears to be a safe and effective management strategy, with a low risk of VTE recurrence.

Post-treatment residual thrombus increases the risk of recurrent deep vein thrombosis and mortality.

BACKGROUND: Recurrent thromboembolic events after an initial deep vein thrombosis (DVT) are relatively frequent. Residual thrombus in the affected veins on ultrasound scan at the completion of anticoagulant therapy has been described as a recurrence risk factor, and may have utility in stratifying those patients at risk. OBJECTIVES: The aims of the study were to correlate the risk of recurrence of DVT with the results of ultrasound at completion of oral anticoagulant therapy. A secondary aim was to review the mortality in this population. PATIENTS: A cohort of 316 DVT patients was included. The patients were divided into those with completely clear vessels on follow-up scan (45%) and those with residual thrombus identified (55%). RESULTS: The cumulative incidence of recurrence was 10% by 2 years and 23% by 5 years. Patients with residual thrombus on follow-up ultrasound were at higher risk of recurrence (hazard ratio [HR] 2.2, 1.19-4.21; P = 0.012) which remained significant after multivariate adjustment for age, gender and malignancy (HR 2.2, 1.15-4.17; P = 0.018). During follow-up, the cumulative mortality was 12% at 2 years and 27% by 5 years. The risk of death was increased in patients with residual thrombus on follow-up scan (HR 3.9, 1.93-7.71; P < 0.001) and this risk persisted after multivariate analysis of age, gender and malignancy (2.8, 1.37-5.72; P = 0.005). The majority of deaths were due to malignancy (68%) however 10 (18%) died from vascular causes. There was a trend towards increased vascular death in the patients with residual thrombus on follow-up ultrasound scan, which did not reach significance (HR 4.1, 0.87-19.33; P = 0.13). CONCLUSIONS: Consistent with previous cohort studies, recurrence risk is increased in patients with residual thrombus on ultrasound. The increased risk of death in patients with residual thrombus, with a trend towards increased vascular death, may suggest that failure of thrombus resolution is a marker of more global vascular dysfunction.