THE non-specific nature of the signs and symptoms of deep vein thrombosis means GPs and other physicians must maintain a high index of suspicion for the potentially deadly condition.

In a narrative review published today by the MJA, the authors wrote that the clinical presentation of DVT was “often non-specific”.

Deep vein thrombosis (DVT) is a common manifestation of venous thromboembolism, and usually occurs in the deep veins of the legs or arms. Mortality is high; death within 30 days occurs in about 6% of patients with DVT, primarily through pulmonary embolism. Among treated patients, about 20–50% develop post-thrombotic syndrome after DVT.

“Accurate diagnosis requires sequential integration of clinical features, assessment of pre-test clinical probability, and confirmatory investigations that include D-dimer testing and imaging,” wrote the authors, led by Professor Graeme Hankey, Professor of Neurology at the University of Western Australia, and Dr Paul Kruger, a haematologist at Fiona Stanley Hospital, PathWest Laboratory Medicine, and the Population Health Research Institute in Canada.

“Symptoms and signs of leg or pelvis DVT include leg pain, swelling, erythema and dilated superficial veins. Arm DVT has similar symptoms localised to the arm. Some DVTs are asymptomatic.”

Alternative diagnoses for limb DVT include cellulitis, lymphoedema, chronic venous insufficiency, haematoma and, for leg DVT, ruptured Baker cyst, they wrote.

Anticoagulation remains the gold standard treatment for DVT, with options including direct oral anticoagulants (DOACs) such as apixaban or rivaroxaban, initial parenteral anticoagulation followed by a DOAC (dabigatran or edoxaban) or initial parenteral anticoagulation overlapped by warfarin and continued for at least 5 days.

“The choice of anticoagulant should consider medical issues such as efficacy, safety, renal and hepatic function, and concurrent medications,” Hankey and colleagues wrote. “In addition, practical issues such as availability, familiarity of use, patient preference, and cost should be considered.”

Compression stockings have been shown to have a beneficial effect after diagnosis. In rare cases, inferior vena cava filters, thrombolysis and surgical thrombus removal may be considered.

Situations that are likely to have an impact on the choice of anticoagulant agent and duration of treatment include DVT that occurs in pregnant women, patients with cancer, distal DVT, recurrent DVT, antiphospholipid syndrome or patients with superficial vein thrombosis, Hankey and colleagues wrote.

In an exclusive MJA podcast, Dr Kruger said that patients with cancer were at higher risk of developing DVT, and low molecular weight heparin was for many decades the preferred treatment.

“That was based on evidence that low molecular weight heparin was associated with a lower risk of recurrent DVT than warfarin (7% v 11%),” he said. “But the problem with low molecular weight heparin is that a lot of patients prefer not to have injections every day over the long term to treat their clots.

“Fortunately, now we’ve got good evidence that is helpful to treat patients with cancer who have a DVT… which tells us that rivaroxaban (a DOAC) is a very good treatment for patients with DVT. The outcomes were a non-significant difference in the rate of recurrent venous thromboembolism (VTE). It’s a very reasonable option for patients with cancer and a VTE.”

Secondary prevention of DVT after the first occurrence was predicated by the individual patient’s type of risk factors, Dr Kruger told InSight+.

“When a patient develops a DVT we always take a careful history for the risk factors and we determine whether the patient has a transient risk factor – it’s only present for a short time; for example, surgery, or pregnancy, or trauma. The next category of risk factor is permanent or persisting; for example, chronic inflammation or cancer that is not curable. Finally, patients who do not have temporary or persisting risk factors, have unprovoked DVT.

“The lowest risk of recurrence occurs in transient DVT; higher risk is in patients with persisting risk factors or in patients with unprovoked DVT.”

Research in the field is focused on optimal treatment and optimal secondary prevention, Dr Kruger said.

Above all, the authors urged GPs to keep their DVT antenna on high alert.

“The diagnosis of DVT requires a high index of suspicion because symptoms and signs are often non-specific,” they concluded. “Anticoagulation continues to be the cornerstone of therapy. The optimal anticoagulant and duration of therapy are determined by the clinical assessment.”

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