Single negative compression ultrasound may rule out DVT
MedWire News: A single negative compression ultrasound (CUS) result may be sufficent for ruling out deep vein thrombosis (DVT) and withholding anticoagulation therapy in some patients, suggest the results of a meta-analysis.
The research, published in the Journal of the American Medical Association, included a predominance of patients with a low pretest probability of venous thromboembolism (VTE), and the researchers suggest future research should focus on patients with significant risk factors, such as those who are pregnant or have cancer.
“Using a single negative whole-leg CUS result as the sole diagnostic modality in patients with high pretest probability of DVT requires further study," say Scott Stevens (Intermountain Medical Center, Murray, Utah, USA) and co-workers.
The team searched medical databases for studies reporting the outcome of patients with suspicion of lower-extremity DVT who did not receive anticoagulation after a negative whole-leg CUS, and were followed-up for VTE for at least 90 days.
The meta-analysis included seven studies with 4731 patients, of whom 13.7% had cancer and 15.3% had recently undergone major surgery.
Overall, VTE or suspicion of VTE-related death occurred in 0.7% of the patients. Specifically, 32.4% of these patients developed distal DVT, 20.6% proximal DVT, 20.6% nonfatal pulmonary embolism, and 26.5% died from causes possibly related to VTE. This gave a combined 3-month rate for VTE of 0.57%, report Stevens et al.
Low-, intermediate-, and high-risk Wells pretest probability scores were given for 66.2%, 28.9%, and 4.9% of patients. The pooled VTE incidence rates for these groups were 0.29%, 0.82%, and 2.49%, respectively. Patients with an intermediate or high risk for VTE were 3.8 times more likely to develop VTE than low-risk patients.
Robert McNutt (Rush University Medical Center, Chicago, Illinois, USA) and Edward Livingston (University of Texas Southwestern Medical Center, Dallas, USA) comment in an accompanying editorial: “Based on the meta-analysis… clinicians may infer that not initiating anticoagulation treatment after a negative CUS result in some surgical or ambulatory patients at low risk of having VTE may be appropriate.
“However, that inference may not be true for hospitalized patients or those with cancer. Greater detail about individual patient scenarios is necessary to facilitate better application of the study results to individual patients,” they conclude.
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By Lynda Williams