Susceptivity Vessel Sign In Cardioembolism Due To Atrial Fibrillation: Association Between Blood Viscosity And Dihomo--linolenic Acid

Background and Purpose: Blood viscosity (BV) is associated with blood stagnation leading to thrombosis. Some polyunsaturated fatty acids (PUFAs) are said to have an antithrombotic effect. First, we aimed to determine the association between BV and the presence of the susceptivity vessel sign (SVS) in patients with cardioembolism (CE) due to atrial fibrillation (AF). Second, we aimed to reveal the association between BV and PUFAs levels. Methods: Consecutive patients with ischemic stroke who met the following inclusion criteria were included: 1) patients with CE, defined by TOAST classification, secondary to AF; 2) onset to door time within 24 h; 3) availability of MRI, including susceptibility-weighted images, obtained at our hospital before IV rt-PA and/or MT; and 4) availability of PUFAs measurements on the day of or the day after the hospital visit. Hematocrit-derived BV at high shear rate (300 sec -1 ) was calculated using the following formula: BV = 1.4175+ 5.878*Ht - 12.98*Ht 2 + 31.964*Ht 3 (Ht = Hematocrit/100). First, we assessed whether BV could be associated with the presence of SVS. Second, we evaluated whether some PUFAs (dihomo-γ-linolenic acid [DGLA], arachidonic acid, eicosapentaenoic acid, docosahexaenoic acid) levels could be the factors associated with BV. Results: We screened 1,720 consecutive ischemic stroke patients and included 137 patients (95 [69%] male, median age 73 years). Of 137, SVS was observed in 83 (61%) patients. In multivariable logistic regression analysis, BV was independently associated with the presence of SVS (odds ratio [OR] 0.391, 95% confidence interval [CI] 0.18-0.86, p = 0.02, Figure). Multiple linear regression analysis revealed a significant positive association between DGLA levels and BV (unstandardized coefficient 0.01, 95% confidence interval 0.01 to 0.02, p < 0.01). Conclusions: Lower BV might be related to the presence of SVS with CE due to AF and DGLA level might be positively associated with BV.