Absence of Susceptibility Vessel Sign points to malignancy in stroke patients

The absence of the Susceptibility Vessel Sign (SVS) on baseline MRI is associated with the presence of active and occult malignancy in patients with acute ischemic stroke eligible for mechanical thrombectomy. SVS absence may increase the chance of detecting paraneoplastic coagulation disorders and occult malignancy in acute ischemic stroke patients.

One of the clinical applications of susceptibility-weighted imaging in brain MRI is the detection, in the acute stage of stroke, of intravascular thromboembolism, called the SVS. The presence of SVS on gradient-echo imaging or susceptibility-weighted imaging is strongly associated with a high proportion of red blood cells and a low proportion of fibrin and platelets in retrieved thrombi on MRI, as well as the presence of active malignancy.

A single-centre, retrospective, cross-sectional study, presented by Dr Morin Beyeler (Bern University Hospital, Switzerland), hypothesised that the absence of SVS is associated with underlying malignancy, because of shared histological clot findings [1]. The study also looked at the diagnostic value of SVS as a biomarker for malignancy-related stroke alone and in combination with other common malignancy biomarkers. Dr Beyeler was the winner of the EAN 2022 tournament for best clinical presentation by a neurologist in training.

The study included 577 patients, treated for acute ischemic stroke with mechanical thrombectomy and with available SVS status between January 2011 and December 2018. Of this cohort, 40 (6.9%) patients had active malignancy (9 occult) at the time of the index stroke while 72 patients (12.5%) showed no SVS. The absence of SVS was strongly associated with active malignancy (aOR 4.85; 95% CI 1.94–12.11) and occult malignancy alone (aOR 11.42; 95% CI 2.36–55.20). Compared with patients with no malignancy, patients with active malignancy:

• Were less often independent before stroke (mRS ≥2): 82.5% versus 92.4% (P=0.039);
• Were more often using anticoagulation before stroke: 35.0% versus 9.7% (P<0.001);
• Received less often bridging therapy: 12.5% versus 41.0% (P<0.001).

With regard to the diagnostic accuracy of the absence of SVS for active malignancies, the sensitivity was 20.83% and the specificity 95.05%. For occult malignancies (after exclusion of active known malignancies), the sensitivity was 8.06% and the specificity 99.17%.

Do these data make the absence of SVS a new biomarker for malignancy-related stroke? There is an association, but causality has not yet been proven. However, the adjusted odds ratio is higher than that of other known predictors. The low sensitivity may be compensated by a high predictive value. “SVS as a new biomarker could perhaps help to accelerate the diagnosis of occult malignancies,” Dr Beyeler concluded. “It may also help to guide secondary prevention, malignancy-related stroke usually being treated with low-molecular weight heparins or with anticoagulants.”

1. Beyeler M, et al. Absence of Susceptibility Vessel Sign in Patients with Malignancy-related Acute Ischemic Stroke. OPR-012, EAN 2022, 25–28 April, Vienna, Austria.

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Posted on 22 August, 2022