Background and Purpose Spontaneous echo contrast (SEC) is thought to r
epresent a risk factor for cardioembolic stroke. In vitro studies sugg
est that SEC results from interaction between red cells and fibrinogen
. To better understand the relation between SEC and stroke and to inve
stigate the in vivo genesis of SEC, we examined the relation between S
EC, the constituents of the blood, and plasma and serum viscosity in p
atients with acute stroke or chronic cerebrovascular disease. Methods
Fifty patients with acute stroke or chronic cerebrovascular disease re
ferred for transesophageal echocardiogram (TEE) were studied by transt
horacic echocardiography and TEE. Complete blood count, fibrinogen, al
bumin, gamma-globulin, and plasma and serum viscosity determinations w
ere made. Left atrial SEC was graded as absent, mild, or marked by mea
ns of TEE. Results SEC was absent in 31 patients, mild in 10 patients,
and marked in 9 patients. Higher grade of SEC was associated with a s
ignificantly greater percentage of patients with atrial fibrillation a
nd larger left atrial dimension. Atrial fibrillation was present in 23
% of the patients in the SEC absent group, 50% of the patients in the
mild SEC group, and 78% of the patients in the marked SEC group (P<.01
). Left atrial diameter averaged 3.8 +/- 0.6 cm in the SEC absent grou
p, 4.3 +/- 1.1 in the mild SEC group, and 4.9 +/- 0.7 in the marked SE
C group (P<.001). Hematocrit, white blood cell count, and platelet cou
nt did not differ among the three groups. Fibrinogen, gamma-globulin,
plasma viscosity, and serum viscosity values were all significantly hi
gher in the presence of SEC (P<.05). Fibrinogen values were 361 +/- 97
mg/dL in the SEC absent group and 427 +/- 135 mg/dL in the marked SEC
group. gamma-Globulin levels were 0.75 +/- 0.23 g/dL in the SEC absen
t group and 1.06 +/- 0.48 g/dL in the marked SEC group. Both plasma vi
scosity (1.97 cp) and serum viscosity (1.64 cp) were higher in the mar
ked SEC group than in the SEC absent group (1.77 and 1.50 cp, respecti
vely). Conclusions In patients with acute stroke or chronic cerebrovas
cular disease, the severity of SEC was not related to albumin, hematoc
rit, white cell count, or platelet count but rather to elevated fibrin
ogen levels and concomitant increases in both plasma and serum viscosi
ty. Moreover, increasing grade of SEC was associated with significantl
y increased left atrial diameter and a higher percentage of patients i
n atrial fibrillation.