Patient follow-up after negative lower extremity bedside ultrasound for deep venous thrombosis in the ED

To evaluate the rate of patient compliance with follow-up ultrasound (US) examinations 5 to 7 days after emergency physician EP performed US exams to rule out lower extremity deep venous thrombosis (DVT) in the ED.

This was a prospective observational study at a level I ED with a residency program, US training program, and an annual census of 75000. Hospital-based emergency US credentialing is available and derived from American College of Emergency Physicians guidelines. Five US-credentialed emergency physicians participated in the study. All patients who received negative lower extremity DVT US exams were eligible. All higher risk patients were given verbal and written instructions and provided with prescriptions to have a follow-up US examination 5 to 7 days after their examination in the ED. Those classified as "low risk" based on Wells criteria were excluded. After 3 months, patients were contacted via telephone and asked questions regarding their follow-up US examinations, reasons for not following up, continued symptoms, and thromboembolic events. Statistical methods included descriptive statistics.

One hundred fifty-nine patients were eligible for enrollment during the 10-month study period. Eighty-five patients (54%) fell into the higher risk category of these; 54 (64%) were contacted successfully. Fifteen (28%) of the patients contacted had obtained a follow-up US exam. Of the 39 who did not follow-up, 29% were told by their physician that a follow-up US was unnecessary, 21% forgot to follow-up, 8% did not follow-up for financial reasons, 16% felt better, 5% could not arrange a study, 21% were unsure. One patient died from sepsis before a follow-up scan. Two patients were diagnosed with DVT, one at 7 days follow-up and the other 9 months later (this particular patient had their 7-day scan cancelled by their primary care physician).

Patients who were instructed to obtain follow-up lower extremity US examinations to rule out propagation of unseen, distal DVTs did so at a very low rate in our study. One of the largest impediments in our study population was a patients' primary care physician who may not understand the need for a follow-up US examination.