Venous thromboembolism. A contemporary diagnostic and therapeutic approach

Patients with risk factors for VTE and developing signs or symptoms remotely consistent with DVT or PE should undergo formal testing. Ultrasound and IPG have good sensitivity and specificity in symptomatic DVT. V/Q lung scans should be obtained in all patients with suspected PE or proven DVT. A prior clinical assessment of probability, based on risk factors, history, physical examination, chest film, and arterial blood gas analysis, can aid in the interpretation of V/Q scans. Normal scans exclude PE. High-probability scans confirm PE if the clinical probability is at least intermediate. Nondiagnostic scans are common, but diagnosis in such cases can be aided by noninvasive leg studies. Heparin therapy should be started when there is suspicion of VTE. To avoid recurrence, a therapeutic aPTT of 1.5 to 2.5 times the control rate should be achieved as soon as possible after the diagnosis of VTE is confirmed. Thrombolytics are reserved for hemodynamically compromised patients. Warfarin should be administered to achieve an INR of 2.0 to 3.0 and should be continued for at least 3 months in patients with low risk of recurrence and probably for at least 6 months in all other patients.