Hematology Clinical Resource Area: Deep Vein Thrombus Overview

Venous thrombus can occur in any vein of the cardiovascular system. These occur most often in the veins of the lower extremities. Deep vein thrombus (DVT) can develop in healthy specimens as well as the chronic or acutely ill patient. Thrombotic events, including deep vein thrombosis (DVT), occur in 15-40% of persons with cancer. This is a blood clot that develops in the deep veins with mild inflammation and little adherence to the blood vessel allowing the clot to travel throughout the body to various locations, potentially causing serious complications. Causes in the cancer patient include medications such as estrogen, tamoxifen, and thalidomide. Smoking, immobility, obesity, advanced age and venous access devices can also be risk factors. Finally, a DVT can be associated with return and metastasis of the malignancy. Symptoms associated with a DVT include mild inflammation and tenderness at the venous site. This page focuses on the risk factors, early detection and treatment of this problem.

Anticoagulant therapy is used for both prevention and treatment of thrombus. Anticoagulant therapy is initiated as injection combined with oral agents. As the patient develops satisfactory coagulation they will discontinue oral agents, per practitioner assessment of clinical symptoms subsiding. Co-existent health conditions will influence therapy type and duration. Patients may require surgical placement of venous filter. The filter is placed in or near the vena cava. Patient selection for filter placement is usually related to history/frequency of thrombus and medication therapy. Routine and frequent serum samples to asses the efficacy of therapy is required for successful treatment of DVT's.

Diagnosis: Most patients present to a practitioner with symptoms ranging from vague aching of affected extremity to an area of obvious vascular compromise. These compromising symptoms may include complaint of pain to extremity most especially when upright or ambulating. The patient will experience reddening of extremity with erythema. In the event that the DVT has dislodged a thrombus presentation changes. The dislodged thrombus could be an embolus in the pulmonary vascular system. This is now a pulmonary embolus. The patient will complain of shortness of air and may experience chest pain with respiration.

Patients with symptoms of DVT will most likely need a venous study to identify area of involvement and percentage of occlusion. When DVT of lower extremities is suspected this will most likely be a duplex ultrasound. In some cases it is necessary fro the patient to have a venography. MRI will also be ordered if further study is necessary. Patients with known clotting disorders will also potentially require laboratory testing of clotting factors in addition.

Disease Overview: Patients with altered mobility patterns, known clotting disease and those with prolonged recovery following surgical procedures are a greater risk of developing DVT to lower extremities. Most DVT are unilateral. Although the thrombus may extend beyond one vein and potentially include multiple veins of the extremity. The degree of occlusion can be noted in most venous radiology studies. Certain medication therapies such as birth control medications and hormone manipulation therapy experience an increased incidence of thrombus formation. Those individuals with contributing health states should be monitored closely for DVT. These include but are not limited to the following: obesity, varicose venous disease, mechanical heart valve(s), sedentary lifestyle/career and cigarette smokers. Practitioners can modify therapies and adjust treatment plans to decrease risk of developing DVT. Patient education of symptoms and signs are necessary for all at risk patients.

Tools: Patients should be encouraged to alert all their healthcare providers of anticoagulation therapy. In addition the patient and caregiver should be advised to contact their health care provider prior to initiating any new medication due to interactions. Patient and caregivers should be informed of bleeding risk with surgical procedures, dental procedures and trauma. In the event of prolonged anti-coagulation therapy patients should be provided information regarding obtaining medical alert jewelry.

Additional Resources

ASA - CDC Health Promotion Program: Deep Vein Thrombosis
Chapter 4 offers a variety of resources and references for the health care professional and layperson.

Evidence Based Summary on DVT
Knowledge of risk factors and early detection are important factors in the treatment of DVT. This AHRQ site summarizes research on which to base clinical guidelines, performance measures, and other quality improvement tools to utilize in the management of DVT.

National Heart Lung and Blood Institute; Diseases and Conditions Index
DCI Home: Blood Diseases: Deep Vein Thrombosis: What Is… The National Heart and Blood Institute's Diseases and Conditions Index (DCI) provides a quick and easy way to get complete and dependable information about heart, lung, and blood diseases and sleep disorders including DVTs.