Nonleg venous thrombosis in critically ill adults a nested prospective cohort study

SUMMARY: The CDC estimates that approximately 1-2 per 1000 individuals develop Deep Vein Thrombosis/Pulmonary Embolism (PE) each year in the United States, resulting in 60,000-100,000 deaths. Even though Deep Vein Thrombosis (DVT) commonly occurs in the lower extremities, Non-Leg Deep Venous Thromboses (NLDVT) at other sites including the head and neck, trunk, and upper extremities can occur. The incidence, risk factors, management and outcomes in this patient group remains unclear. The authors therefore conducted a prospective cohort study in the ICU setting. This study is nested in a larger international trial in which 3746 patients, expected to remain in the med/surg Intensive Care Unit (ICU) for at least 3 days, were randomized to receive either Unfractionated (standard) heparin or Dalteparin (FRAGMIN®) for thromboprophylaxis. The authors characterized the NLDVT as Prevalent or Incident (depending on whether the thrombosis was identified within 72 hours of ICU admission or developed after the third ICU day) and whether they were catheter related or not. Risk factors for NLDVT and subsequent anticoagulant therapy, associated PE, and death were evaluated. Several important findings were noted from this study. Of the 3746 patients, 2.2% developed 1 or more Non-Leg Vein Thromboses (superficial or deep, proximal or distal). Majority of these thrombotic events (95%) occurred in the upper extremity and most of these occurred in the clinically important proximal and deep venous system. Further, these thrombotic episodes were more commonly Incident (2.0%) rather than Prevalent (0.2%) – P <0.001. It was noted that 1 in 7 patients with NLDVT developed PE. It appears that malignancy, hospitalization and Central Venous Catheters are risk factors for Upper Extremity Deep Vein Thrombosis (UEDVT), but the disproportionate increase in the incidence of UEDVT in hospitalized patients (30%-40% of hospital associated DVT’s) has been attributed to the increased use of CVC’s such as PICC (Peripherally Inserted Central Catheter). In this study, only 13% of the patients diagnosed with NLDVT received anticoagulation therapy. In an accompanying commentary by Dr. Greg Maynard, it was well pointed out that UEDVT is associated with similar rates of recurrence, PE and mortality as lower extremity DVT and as such UEDVT should be treated with anticoagulant therapy similar to Lower Extremity DVT. Dr. Maynard also noted that PICC associated DVT could be significantly reduced by appropriately choosing patients for a PICC line, proper PICC placement, early PICC removal, smaller diameter PICC and smaller number of lumens in the catheter. The authors concluded that despite universal prophylaxis with heparin, there was a high incidence of NLDVT in clinically important locations of the venous system, in critically ill patients and this calls for more structured preventive measures, as we learn more about this entity. Lamontagne F, McIntyre L, Dodek P, et al. JAMA Intern Med. 2014;174:689-696