Duplex Doppler evidence of high hepatic artery resistive index after liver transplantation: Role of portal hypertension and clinical impact

Role of Doppler Trasonography in Predicting Recovery From Early Allograft Dysfunction in Liver Postoperative Patients

OBJECTIVE

The aim of this study was to observe the recovery of liver function in patients with early allograft dysfunction (EAD) at one month postoperatively and explore whether early postoperative ultrasonic hemodynamic parameters can predict this outcome.

METHODS

Patients with EAD postoperatively, who underwent orthotopic liver transplantation (OLT) in our hospital from December 2012 to June 2021, were retrospectively collected. Based on the recovery of liver function within one month, patients were divided into two groups: the recovery group (FR-1M) and the non-recovery group (Non-FR-1M). Ultrasonic hemodynamic parameters within the first seven days postoperatively were compared between the two groups.

RESULTS

Among the 254 EAD patients included in this study, 158 (62%) patients recovered their liver function within one month. Of the 96 (38%) patients who did not recover, The RI of the non-FR-1M group was significantly lower than that of the FR-1M group on postoperative day 6 (POD6) and POD7. In the high resistance interval (RI all > 0.7), Group FR-1M represents a significant proportion (29/3, ratio 12/1), while in the low resistance interval (RI < 0.5 at least once), Group non-FR-1M accounts for a relatively high proportion (12/27, ratio 5/11). In the middle resistance interval (more than 1 time ≤ 0.7 and all ≥ 0.5), the proportions of the two groups are balanced (85/88, ratio 1/1).

CONCLUSION

Liver function typically recovers within 1 month in most patients with EAD. The high resistance state of the hepatic artery in the early postoperative period is illustrative an important role in its recovery. Low-resistance state is most unfavorable for the recovery of liver function.

Portal hypertension-like pattern in coronavirus disease 2019 acute respiratory distress syndrome

OBJECTIVES

Although respiratory failure is the most common feature in coronavirus disease 2019 (COVID-19), abdominal organ involvement is likewise frequently observed. To investigate visceral and thoracic circulation and abdominal organ damage in COVID-19 patients.

MATERIALS AND METHODS

A monocentric observational study was carried on. In COVID-19 patients affected by acute respiratory distress syndrome (ARDS) (n = 31) or mild pneumonia (n = 60) thoracoabdominal circulation was evaluated using Doppler-ultrasound and computed tomography. The study also included non-COVID-19 patients affected by ARDS (n = 10) or portal hypertension (n = 10) for comparison of the main circulatory changes.

RESULTS

Patients affected by COVID-19 ARDS showed hyperdynamic visceral flow and increased portal velocity, hepatic artery resistance-index, and spleen diameter relative to those with mild-pneumonia (p = 0.001). Splanchnic circulatory parameters significantly correlated with the main respiratory indexes (p < 0.001) and pulmonary artery diameter (p = 0.02). The chest and abdominal vascular remodeling pattern of COVID-19 ARDS patients resembled the picture observed in the PH group, while differed from that of the non-COVID ARDS group. A more severe COVID-19 presentation was associated with worse liver dysfunction and enhanced inflammatory activation; these parameters both correlated with abdominal (p = 0.04) and chest imaging measures (p = 0.03).

CONCLUSION

In COVID-19 ARDS patients there are abdominal and lung vascular modifications that depict a portal hypertension-like pattern. The correlation between visceral vascular remodeling, pulmonary artery enlargement, and organ damage in these critically ill patients is consistent with a portal hyperlfow-like syndrome that could contribute to the peculiar characteristics of respiratory failure in these patients.

CLINICAL RELEVANCE STATEMENT

our data suggest that the severity of COVID-19 lung involvement is directly related to the development of a portal hyperflow-like syndrome. These observations should help in defining the need for a closer monitoring, but also to develop dedicated therapeutic strategies.

Utility of nifedipine use for Doppler ultrasound early after liver transplantation to predict short-term complications and long-term outcomes

PURPOSE

To evaluate the response to nifedipine administration measured by changes in hepatic arterial (HA) flow on post-operative Doppler ultrasound (US) to predict short-term complications and long-term outcomes in liver transplant (LT) patients.

METHODS

Patients who underwent LT with post-operative Doppler US within 3 days between 1 January 2005 and 31 December 2015 were included in this retrospective single center study. The patients who received and did not receive nifedipine during the Doppler US comprised the study and control groups, respectively. A positive response to nifedipine was defined as the detection of HA flow when none was present initially or a reduction in HA resistive index (RI) ≥ 0.1 after nifedipine administration. The rates of re-transplantation, re-operation, percutaneous intervention (PCI), and overall survival (OS) were recorded. Cox proportional hazards regression was used to evaluate the association of clinic-demographic variables and Doppler findings with the outcome measures.

RESULTS

444 LT patients (305 M/139F, mean age 51.7 ± 17.4 years, mean interval between LT-Doppler US 1.12 ± 0.9 days) are presented. 220 patients comprised the nifedipine study group [n = 157/220 (71.4%) responder, n = 63/220 (28.6%) nonresponder] and 224 patients comprised the control group. There was no difference in re-transplantation or PCI rates between the groups (all p-values ≥ 0.2 and ≥ 0.08, respectively). The responder group had a lower rate of re-operation vs. the control group (15.9% vs. 24.1%, p = 0.03) and nonresponder group (15.9% vs. 31.8%, p = 0.004). 1-year and 2-year OS were similar between the groups (all p-values > 0.37).

CONCLUSION

Short-term complication rates and long-term outcomes for patients with liver transplant who responded to nifedipine administration on Doppler US are similar to those who did not require nifedipine administration. A lack of response to nifedipine was associated with a higher re-operation rate.

Low hepatic artery resistive index on Doppler ultrasound performed on the first post-liver transplant day is associated both with hepatic artery thrombosis and decreased graft survival

PURPOSE

Although liver transplantation (LT) outcomes have improved significantly over the last decades, early vascular complications are still associated with elevated risks of graft failure. Doppler ultrasound (DUS) enables detection of vascular complications, provides hepatic artery Resistive Index (RI). The aim of our study was to evaluate the association of the RI parameters of DUS performed in the first post-transplant week with post-transplant outcomes.

METHODS

All consecutive patients undergoing a first LT between 2001 and 2019 at a single center were included. Patients were divided into two groups: RI < 0.55 and RI ≥ 0.55. Patients were also divided according to the presence or absence of hepatic artery thrombosis (HAT). Graft survival was compared between groups.

RESULTS

Overall, 338 patients were included. HAT occurred in 23 patients (6.8%), of which 7 were partial and 16, complete. Biliary complications were more common in patients with HAT (10 [43.5%]) vs. 38 [12.1%] [p < 0.001]). Graft survival was lower for patients with HAT (p = 0.047). Also, RI < 0.55 was associated with increased incidence of HAT (p < 0.001). Additionally, patients with RI < 0.55 on post-operative day 1 had decreased graft survival as compared to patients with RI > 0.55 (p = 0.041). RI on post-operative day 3 and 5 was not predictive of inferior graft outcomes.

CONCLUSIONS

Intensive use of DUS in the early post-LT period offers the possibility of early diagnosis of vascular complications, guiding medical and surgical management of HAT. Additionally, according to our data, low RI (< 0.55) on the first postoperative day also is a predictor of HAT and decreased graft-survival.

Splenic Artery Embolism in Liver Transplant Patients: A Single-Center Experience

BACKGROUND

Hypersplenism, portal hypertension, and ascites have been seen after liver transplants. Patients are usually treated medically with refractory patients potentially undergoing splenectomy. Splenic artery embolism (SAE) is an alternative that can be performed to limit the surgical intervention that may have the benefit of improving portal hypertension. Few studies have studied the effect on main portal vein (MPV) velocities and hepatic artery resistive indices (HARIs) which may be beneficial as markers of portal hypertension.

PURPOSE

This study aims to evaluate the efficacy and safety of interventional radiology (IR)-guided SAE for the management of portal hypertension in patients who have had liver transplants.

METHODS

A retrospective analysis was conducted on liver transplant patients who had undergone IR-guided SAE post-transplant at a single tertiary transplant center from 2012 to 2022. The primary outcome of intervention efficacy was quantified by peak HARIs and MPV velocities. Ultrasound with Doppler obtained before and after the intervention was reviewed for these parameters. Secondary outcomes included adverse events at the time of the procedure and within one year of the procedure, the need for splenectomy, and spleen size.

RESULTS

Twenty-eight patients met the criteria for inclusion. The mean age of patients was 52.5 years (21-71 years) and the time after transplant was 149.5 days (2-1588 days). About 96.4% of SAEs were technically successful (n=27). Twenty-one patients had MPV velocities available, and 24 had peak HARIs available. In these patients, HARIs decreased by an average of 0.063 (95% CI 0.014-0.112) after SAE. MPV velocity decreased by an average of 47.2 cm/s (95% CI 27.3-67.1) after SAE. About 10.4% of patients (n=3) developed a procedure-related complication, all of which were femoral access site aneurysms. No (0) patients suffered from bleeding, infections, or abscesses after the procedure. About 10.7% of patients (n=3) required splenectomy after SAE: one splenectomy was due to technical failure and two were due to refractory symptoms.

CONCLUSION

We performed one of the first analyses on MPV and RI and showed that our patients saw an improvement post-embolization with a theoretical improvement in portal hypertension. The complication rate and risk of infection seem to be acceptable risks, making SAE a feasible option for management.

Doppler evaluation of hepatic hemodynamics after living donor liver transplantation in infants

Objective: The aim of this study was to explore the hemodynamic changes of hepatic artery and portal vein detected by Doppler ultrasound (DU) in infants who underwent living donor liver transplantation (LDLT).

Methods: The data of 41 infant patients (22 Males, 19 Females, median age of 5 months) were collected in the Children’s Hospital affiliated to the Chongqing Medical University from May 2018 to December 2019. The patients underwent left lateral segment LDLT (LLS -LDLT) because of biliary atresia (BA). Hemodynamic parameters, including the peak systolic velocity (PSV), resistivity index (RI) of the hepatic artery (HA), portal vein velocity (PVV), and portal vein flow (PVF) were recorded from Doppler ultrasound on the day before the operation, and on the 1st, the 7th, the 14th and the 30th day after LDLT procedures. The changes of PSV_HA, RI_HA, PVV and PVF before and on the 1st day after transplantation were analyzed by paired t-test. The comparison of the data between different postoperative time points were assessed by ANOVA.

Results: Compared with the parameters measured before LDLT, PSV_HA, and RI_HA decreased, and PVV and PVF increased significantly (p < 0.001) on the 1st day after LLS-LDLT. As for PSV, there was no significant difference between the 7th day and the 1st day after transplantation (POD7 VS POD1, p = 0.167) while there was a substantial difference between the 14th, 30th and 1st day after LT (POD14 vs. POD1, p = 0.003) (POD30 vs. POD1, p ＜0.001). And there was a significant difference between the 14th, 30th, and 7th days after LT (POD14 vs. POD7, p = 0.014) (POD30 vs. POD7, p ＜0.001). There was no significant difference between 30th and 14th after transplantation (POD30 vs. POD14, p = 0.092). As for RI_HA and PVV, the decrease was slow within the first month after the operation, and there was no significant difference at different times.

Conclusion: We have identified major hepatic flow changes that occurred in 41 infants who underwent LLS -LDLT due to BA. The data could be used for future studies of LDLT in infants including hemodynamic modeling, liver regeneration and clinical management.

Thromboelastography does not reduce transfusion requirements in liver transplantation: A propensity score-matched study

STUDY OBJECTIVE

To compare total blood product requirements in liver transplantation (LT) assisted by thromboelastography (TEG) or conventional coagulation tests (CCTs).

DESIGN

Retrospective observational study.

SETTING

A tertiary care referral center for LT.

PATIENTS

Adult patients undergoing LT from deceased donor.

INTERVENTION

Hemostasis was monitored by TEG or CCTs and corresponding transfusion algorithms were adopted.

MEASUREMENTS

Number and types of blood products (red blood cells, RBC; fresh-frozen plasma, FFP; platelets, PLT) transfused from the beginning of surgery until the admission to the intensive care unit.

METHODS

We compared data retrospectively collected in 226 LTs, grouped according to the type of hemostasis monitoring (90 with TEG and 136 with CCTs, respectively). Confounding variables affecting transfusion needs (recipient age, sex, previous hepatocellular carcinoma surgery, Model for End Stage Liver Disease - MELD, baseline hemoglobin, fibrinogen, creatinine, veno-venous by pass, and trans-jugular intrahepatic portosystemic shunt) were managed by propensity score match (PSM).

MAIN RESULTS

The preliminary analysis showed that patients in the TEG group received fewer total blood products (RBC + FFP + PLT; p = 0.001, FFP (p = 0.001), and RBC (p = 0.001). After PSM, 89 CCT patients were selected and matched to the 90 TEG patients. CCT and TEG matched patients received similar amount of total blood products. In a subgroup of 39 patients in the top MELD quartile (MELD ≥25), the TEG use resulted in lower consumption of FFP units and total blood products. Nevertheless, due to the low number of patients, any meaningful conclusion could be achieved in this subgroup.

CONCLUSIONS

In our experience, TEG-guided transfusion in LT does not reduce the intraoperative blood product consumption. Further studies are warranted to assess an advantage for TEG in either the entire LT population or the high-MELD subgroup of patients.