Recognized and unrecognized clinical venous thromboembolism (VTE) after acute ischemic stroke (AIS): a prospective study using magnetic resonance direct thrombus imaging (MRDTI)

Abstract number: CD094

Kelly^* J. A., Lewis^* R. R., Rudd^* A., Moody† A., Hunt^* B. J.

^*1St Thomas' Hospital, UK †QMC, UK

Background  

We investigated the true incidence of VTE (clinical and subclinical) in patients with AIS receiving standard thromboprophylaxis with aspirin and elasticized stockings using MRDTI, a highly accurate noninvasive technique which allows direct visualization of thrombus. Overall incidences of any VTE, proximal deep-vein thrombosis (PDVT) and pulmonary embolism (PE) at 3 weeks were 40, 18 and 12%, most of which were subclinical. In patients with severe stroke, incidences were 63, 30 and 20%. As part of this study, we were able to monitor patients to determine whether under-ascertainment of clinical events occurred. This has long been suspected poststroke but remains unproven.

Methods  

One hundred and two patients with AIS were sequentially recruited. One hundred underwent MRDTI of the legs between days 7–14; 78 underwent repeat imaging between days 21–28. When DVT was identified, thoracic imaging was performed to identify PE. Clinical events diagnosed conventionally and data from postmortem examinations were included. Patients were monitored weekly for possible clinical evidence of DVT (new onset of calf swelling of 3 cm or more) or PE (oxygen saturations 92% or less and/or respiratory rate of >20). ‘Unrecognized clinical’ VTE was defined as proven VTE in combination with these signs which was not recognized by the attending team.

Results  

See Table 1.

Discussion  

Clinically apparent VTE was overlooked as often as it was identified in this study, reinforcing the importance of careful clinical assessment in these patients.

Table 1  Recognized and unrecognized clinical venous thromboembolism (VTE) after acute ischemic stroke (AIS): a prospective study using magnetic resonance direct thrombus imaging (MRDTI)