Vascular complications after liver transplantation: evaluation with Doppler US

Abstract

Although it is clear that Doppler US evaluation is an effective choice for diagnosing vascular complications after liver transplantation, we also observed that Doppler US examination plays an important role in detecting vascular complications intraoperatively and improving the patient's chance for a successful outcome.

Ruolo diagnostico dell’US color Doppler nel I anno di follow-up posttrapianto epatico (OLT)

“…Overall, in our experience CDUS proved to be highly effective for diagnosing biliary complications, showing very good results -even better than those reported in other published works [13]. The use of codified parameters for the study of hepatic perfusion (peak velocity, spectral analysis of flow patterns, flow-tracing morphology and blood flow) allowed us to achieve excellent SN, SP and DA values, as previously described by several authors [4][5][6][7]. Particularly important in clinical terms is the early diagnosis of both hepatic artery thrombosis, which represents the most severe and common vascular complication, affects up to 12% of adult patients and is associated with a 73% mortality rate unless retransplantation is performed; and of anastomotic stricture, which may lead to severe ischaemic damage to the intrahepatic biliary tree.…”

“…[8,9], il tipo di soluzione di preservazione utilizzata [10], il rigetto cronico, le infezioni da citomegalovirus, un danno citotossico mediato dai sali biliari e la terapia immunosoppressiva con ciclosporina [11][12][13] [13]. L'utilizzo di parametri codificati per lo studio della perfusione epatica (velocità di picco, analisi spettrografica dei pattern di flusso, morfologia del tracciato e portata) ha garantito di ottenere ottimali sensibilità, specificità ed accuratezza diagnostica, così come già segnalato da diversi autori [4][5][6][7]. Particolare rilevanza clinica riveste la diagnosi tempestiva sia di trombosi dell'arteria epatica, che è la più grave e comune complicanza vascolare la cui incidenza giunge nell'adulto sino al 12% con mortalità del 73% senza ritrapianto, sia di stenosi serrata dell'anastomosi, che può CDUS allowed ready depiction of blood collections and their characterisation on the basis of their morphology, which changes over time: homogeneously anechoic depositions, inhomogeneous with gravity-dependent hyperechoic depositions, solid and organised.…”

“…Signs of hepatic artery thrombosis were total absence [4][5][6][7]. È stato considerato indicativo di stenosi un flusso turbolento con aumento focale della velocità >2 m/s sul sito di anastomosi, associato ad un tracciato arterioso intraepatico con morfologia di tipo tardus parvus, caratterizzato da un un incremento del tempo di accelerazione sistolica e da una riduzione del picco di velocità sistolica.…”

“…Considering the frequent presence of multiple anastomoses, the study of arterial vessels was performed by sampling the proper, right and left hepatic arteries. Peak systolic velocity (PSV) and spectral analysis of flow patterns were evaluated; we did not consider other parameters suggested in the literature, such as resistive index (RI) and systolic acceleration time (SAT), with cutoff values of 0.5 and 0.08, respectively [4][5][6][7]. Turbulent flows with focal increase in velocity >2 m/s at the site of anastomosis associated with a tardus-parvus pattern of intrahepatic arterial flow, characterised by longer SAT and lower PSV, were considered as indicative of stricture.…”

Imaging in liver transplantation

“…Ultrasound findings can be false positive if the hepatic artery is small or stenotic, if the flow is very slow, or if there is coexistent systemic hypotension. If US does not show an arterial flow, administration of contrast media (microbubble) can help to improve the flow visualization in the HA, differentiating between thrombosis and a patent artery in patients without HA flow on conventional Doppler US [46][47][48][49] . Hepatic artery stenosis is reported in 5%-10% of transplant recipients and can be anastomotic (in 70% of cases), perianastomotic or intrahepatic.…”