Diagnosis and Imaging:
The most frequently relied upon modality for the diagnosis of SASS is
angiography (8). It is defined as a subjective slow flow of blood in the
hepatic artery relative to that in the splenic artery in the absence of
significant artery abnormalities such as hepatic artery stenosis,
thrombosis or kinks (15). Uflacker and coworkers diagnosed SASS when
there is a visualization of hepatic artery during the portal-venous
phase of angiogram (3). However, others have not relied on this
definition or threshold (5). Other modalities for detection of SASS
include regular doppler ultrasonography (US) (14). US is often performed
daily within the first week after OLT. Emergency angiography is
performed when a weakened or decreased signal is detected on US (14). US
findings are nonspecific and are not often used to describe SASS cases
since findings overlap with other conditions such as infection,
transient graft edema, or rejection (16,17,18). The most described US
findings include a high level of arterial resistive index (above 0.8)
(19). Reversal of diastolic flow or low diastolic flow is also often
observed (3,4). Furthermore, arterial velocities are rarely reported
(17). Nevertheless, US findings are not often used for diagnosis of SASS
(14). In fact, only 30 % percent (34 out of 113) of the SASS cases
reported US findings. Other methods for the diagnosis of SASS include a
splenic volume greater than 830 cm3, which has an almost 75% accuracy
in diagnosing SASS (7,8). Splenic artery diameter of greater than 4.0 mm
or splenic artery to hepatic artery ratio of greater than 1.5 are
considered indicators of SASS (7,8). Some studies have also indicated a
difference of at least 6mm between hepatic and splenic artery diameters
as being predictive of SASS (6). However, no imaging modality truly
solidifies the diagnosis, and the diagnosis is only confirmed upon
seeing improved graft function and increased hepatic arterial perfusion
after correcting splenic artery perfusion.