Survival and recurrent venous thromboembolism in 834 subjects after a first episode of isolated distal or proximal deep vein thrombosis without pulmonary embolism
S. Barco1, M. Corti2, A. Trinchero1, C. Picchi2, S.V. Konstantinides1, C. Ambaglio2, F. Dentali3, M. Barone2 (1Mainz, Germany, 2Pavia, Italy, 3Varese, Italy)
Time: 08:00 - 09:15
Objective: Isolated distal deep vein thrombosis (iDDVT) may be associated with a reduced risk of recurrent venous thromboembolism (VTE) if compared to proximal DVT (pDVT) or pulmonary embolism (PE). However, a few studies focused on patients without previous VTE events. Furthermore, the risk of death following iDDVT has never been investigated. Our cohort study included consecutive individuals followed at a single institution (years 2004-2012) diagnosed with a first-episode index iDDVT or pDV without (a)symptomatic PE. Death and VTE recurrence rates were compared between the two groups.
Methods: Primary outcomes: i) all-cause death, ii) symptomatic recurrent PE or pDVT. Three independent investigators retrieved clinical data from patients´ charts and three adjudicated the outcomes. All patients were routinely scheduled for a yearly clinical control and contacted telephonically if they missed a follow-up visit.
Results: A total of 4,759 medical records were screened and 834 subjects included for the purpose of this study. Of those, 203 had symptomatic iDDVT and 631 had pDVT associated (n=227) or not (n=404) with distal DVT. One-hundred twenty-six recurrent symptomatic pDVT or PE were recorded during follow-up, of which 110 after index pDVT (17.4%) and 16 after iDDVT (7.9%) for rates of 4.5 events/100 patient-years (95CI 3.7-5.4) and 2.0 events/100 patient-years (95CI 1.1-3.2), respectively. Patients with recurrent symptomatic PE during follow-up were 2.5% (of pDVT patients) and 3.0% (of iDDVT patients). After adjustment for length of anticoagulant treatment, age, sex, and DVT risk factors, index iDDVT was associated with a reduced risk of symptomatic recurrent pDVT or PE (adjusted Hazard Ratio 0.32 [95CI 0.19-0.55]). Death occurred in 264 patients (31.7% [95CI 28.6%-34.9%]) during 5,491 patient-years of follow-up: 52 had had iDDVT (25.4%) and 212 pDVT (33.6%). One-year mortality was 12.2% in the two groups. The long-term hazard of death appeared reduced in iDDVT patients (adjusted Hazard Ratio 0.58 [95CI 0.26-1.30]), if only unprovoked events were considered.
Conclusion: iDDVT patients were at a reduced risk of recurrent VTE and long-term death compared to pDVT. One-year mortality was mostly due to active cancer and appeared similar between iDDVT and pDVT groups.