Surveillance duplex scanning to prevent venous thromboembolism: does it make a difference in rehabilitation unit patients?

Hospitalization is the single most important acquired risk factor for developing venous thromboembolism (VTE) [1,2]. The incidence of deep venous thrombosis (DVT) among patients admitted to rehabilitation units is high [3], but clinical signs and symptoms may be difficult to interpret [4]: only 20– 30% of symptomatic outpatients have proven DVT, and 90% of patients with fatal PE are asymptomatic for DVT [5]. The failure of symptoms to predict PE has led to the use of objective methods of examination, including screening compression ultrasound (CUS), which has become the primary non-invasive diagnostic method for DVT [6]. One retrospective study [7] found that one-third of a group of rehabilitation patients had DVT at admission to the rehabilitation unit. These authors proposed that such patients should have ultrasound screening at admission to detect DVT, though there is no evidence that screening ultrasound reduces clinically important outcomes, including PE [8]. To provide additional information on the utility of screening patients at admission to a rehabilitation facility, we undertook a prospective, observational study. All patients admitted to the rehabilitation unit at the Civic Hospital in Modena between January 2006 and December 2008 were considered for enrollment in the study. During the first 18 months of the study (phase 1), all patients underwent bilateral CUS of the deep veins of the leg and thigh within 72 h of admission unless the patient had a clinically suspected thrombotic event before that time. In the following 18 months of the study (phase 2), only patients suspected of having DVT underwent CUS. Patients were followed by telephone or in person every 6 months from discharge to June 2009. Additional information, if required, was obtained from relatives, the primary physician, hospital medical records, and National Health System registry offices. The primary endpoints of the study were death from any cause, and the occurrence of any VTE episode during hospital admission and follow-up after discharge (minimum 6 months, maximum 30 months). Over the course of the study 947 patients were admitted to the rehabilitation unit. The average length of stay was 25 days. Sixty-seven patients were receiving therapeutic anticoagulation at the time of their admission, including 16 patients who had VTE during their acute stay. Thirty patients were deemed ineligible for pharmacologic thromboprophylaxis. These patients were excluded from further analysis. None of the excluded patients developed VTE over the course of their rehabilitation stay. Of the remaining 850 patients, 424 (49.9%) were male. The mean age was 64 ± 15 years. Reasons for admission to the rehabilitation unit are shown in Table 1. Three hundred and seventeen patients were enrolled over the first 18 months of the study, and 533 patients were enrolled in the second 18 months. In total, 531 duplex scans were performed. Overall, symptomatic + screening detected VTE occurred in 14 out of 850 patients [1.6%; 95% confidence interval (CI), 0.9–2.7%]. Two out 14 patients (14%) were discovered because of a screening ultrasound in the first 18 months of the study; one of these two patients had symptoms. In the following period 5 out 12 patients with confirmed DVT (41.7%) reported significant symptoms of DVT. The seven additional DVTs were detected on ultrasound performed as a result of minor clinical symptoms (such as unexplained peripheral edema) or an abnormal laboratory investigation (principally an abnormal D-dimer). None of these patients reported leg pain. The mean time from admission to diagnosis was 10 days. There were seven patients (50%) with proximal DVT, four (28.6%) with distal DVT (none with significant symptoms), two (14.3%) with both DVT and PE, and one (7.1%) with PE. VTEwasmore frequent inmales [11 out of 424 (2.6%)males vs. 3 out of 426 (0.7%) females, P = 0.03], while the mean age was similar to that of patients without VTE (66 ± 12 vs. 64 ± 15 years, P = 0.55). Correspondence: Enrico Tincani, Medicina Interna e Riabilitazione, Nuovo Ospedale S.Agostino-Estense, Via Giardini 1355, Baggiovara, Italy. Tel.: + 39 593961101; fax: + 39 59961419. E-mail: e.tincani@ausl.mo.it