Pulmonary embolism in deep venous thrombosis of the upper extremity: more often in catheter-related thrombosis

Pulmonary embolism (PE) is a major complication of deep venous thrombosis (DVT) of the lower extremities. The incidence is approximately 50%. The incidence of DVT of the upper extremity (DVTUE) is increasing mainly due to the increasing use of central venous catheters. The percentage of PE secondary to DVTUE is still being investigated.The occurrence of PE in DVTUE was retrospectively analyzed in 78 patients with proven DVTUE. Furthermore, the literature was reviewed.Of the identified patients with DVTUE 16 showed a primary DVTUE and 62 a secondary DVTUE. Secondary DVTUE was catheter-related in 41 (60%), which is 53% of all DVTUE. In this study the percentage of PE as a complication of DVTUE was 6 (95% CI: 0.2-30) in primary DVTUE, 13 (95% CI: 6-24) in secondary DVTUE and 17 (95% CI: 7-32) in catheter-related DVTUE. The relative risk for PE of catheter-related DVTUE versus other causes was 3.4 (95% CI: 0.4-53.5). The overall percentage was 12 (95% CI: 5-21). The literature review showed a percentage of 7 (95% CI: 4-9) in the retrospective studies and 17 (95% CI: 12-23) in the prospective studies.Indwelling catheters are the most common cause of DVTUE. PE is not an uncommon complication of DVTUE, and is more common in catheter-related DVTUE. The difference between the incidence of PE in DVTUE and DVT of the lower extremity may be explained by a number of factors, such as differences in fibrinolytic activity, mechanical forces and venous flow patterns.