A total of 344 patients who underwent a first LT were eligible for the study. Of these, 207 (60.2%) were male. The median age was 57 (IQR: 48–62) years. Hepatitis C virus (HCV) infection was present in 219 patients (63.7%). The median calculated MELD score was 15 (IQR: 10–21). Hepatocellular carcinoma (HCC) was present in 164 (47.7%) of the patients. (Table 1). HAT incidence was 6.7% (23/344).
Table 2 demonstrates a comparison between patients who developed HAT (n = 23) and those who did not have HAT (n = 321). Patients who had HAT had a lower calculated MELD score than those without HAT (median of 13 [IQR: 9–14] x 15 [IQR = 10–21]) (p = 0.024). Additionally, the interval between venous and arterial reperfusion was higher among those who had HAT compared to those without HAT (median of 72.5 min [IQR 43.5–97] vs. 50 min [39–70]) (p = 0.021). Biliary complications were also more common in patients with HAT (11 [47.8%]) vs. 44 [13.4%]) (p < 0.001). For all other variables, there was no significant statistical difference between the two groups.
Of the total 23 thromboses (incidence of 6.7% for the entire cohort), 16 (69.6%) were complete and 7 (30.4%) were partial. Twelve thromboses (52.2%) were diagnosed on ultrasound performed within the first 24 hours (1st post-transplant day), 8 (34.8%) were diagnosed on ultrasound on the 3rd post-transplant day, 2 (8.7%) were diagnosed between the 4th and 7th post-transplant day, and 1 (4.3%) on the 29th post-transplant day.
Two out of seven patients with partial thrombosis also received a transcatheter endovascular intervention with intra-arterial alteplase with or without stent placement, being placed on IV heparin as well. Only one patient (14,2%) with partial thrombosis died in the first 30 post-transplant days. As for patients with complete thrombosis, 12 underwent surgical revascularization (arterial thrombectomy with intra-arterial alteplase and redo of arterial anastomosis with or without creation of an arterial conduit). In total, there were 3 (18.7%) graft losses in the first 30 post-transplant days, 2 of which died and 1 underwent retransplantation.
Graft survival in those without HAT at 1-year, 3-years, 5-years, and 7-years was 78.6%, 72.1%, 66.6% e 62.5%. respectively. Meanwhile, graft survival in those with HAT, survival rate at 1-year, 3-years, 5-years, and 7-years were: 60.9%, 50.7%, 50.7% and 44.4% (p = 0.082) (Fig. 1).
For the DUS on the 1st post-transplant day, there were a total of 59 (17.2%) patients with RI < 0.55, 237 (68.9%) patients with RI between 0.55–0.85, 13 (3.8%) patients with RI > 0.85. In 35 (10.2%) patients, DUS on 1st post-transplant day was unavailable. The 1-year, 3-year, 5-year and 7-year graft survival were, respectively, 72.9%, 65.9%, 54.2%, 54.2% for RI < 0.55 vs. 82%, 75.4%, 70.4%, 64.8% for RI 0.55–0.85 vs. 84.6%, 84.6%, 84.6%, 84.6% for RI > 0.85 (p = 0.033). The Hazard ratio was 1.59 (95% CI = 1.01–2.5) for RI < 0.55 vs. RI 0.55–0.85 and 0.39 (95% CI = 0.09–1.59) for RI > 0.85 vs. RI 0.55–0.85 (Fig. 2a).
For the DUS on the 3rd post-transplant day, there were a total of 31 (9.7%) patients with RI < 0.55, 192 (59.8%) patients with RI between 0.55–0.85, and 8 (2.5%) patients with RI > 0.85. In 90 (28%), DUS on 3rd post-transplant day was unavailable. The 1-year, 3-year, 5-year and 7-year graft survival were, respectively, 80.6%, 70.8%, 70.8%, 70.8% for RI < 0.55 vs. 85.2%, 78.6%, 72.4%, 66.5% for RI 0.55–0.85 vs. 87.5%, 87.5%, 58.3%, 58.3% for RI > 0.85 (p = 0.99). The Hazard ratio was 1.06 (95% CI = 0.52–2.14) for RI < 0.55 vs. RI 0.55–0.85 and 1.03 (95% CI = 0.25–4.22) for RI > 0.85 vs. RI 0.55–0.85 (Fig. 2b).
On the 5th post-transplant day DUS, there were a total of 22 (6.8%) patients with RI < 0.55, 197 (61.4%) patients with RI between 0.55–0.85, and 8 (2.5%) patients with RI > 0.85. In 94 (29.3%), DUS on 5th post-transplant day was unavailable. The 1-year, 3-year, 5-year and 7-year graft survival were, respectively, 86.3%, 81.8%, 81.8%, 72.7% for RI < 0.55, 86.5%, 80%, 72.3%, 68.1% for RI 0.55–0.85 and 87.5%, 87.5%, 87.5%, 87.5% for RI > 0.85 (p = 0.76). The Hazard ratio was 0.93 (95% CI = 0.4–2.18) for RI < 0.55 vs. RI 0.55–0.85 and 0.48 (95% CI = 0.06–3.53) for RI > 0.85 vs. RI 0.55–0.85 (Fig. 2c).
Table 3 shows the relationship between RI groups and the incidence of biliary complications. Comparing the rate of biliary complications among the RI groups (< 0.55; 0.55–0.85 and > 0.85) no statistically significant difference was detected.
Table 4 shows a Cox regression model to estimate the role of variables in relation to the outcome of graft survival. The variables bleeding (L) with HR 1.087 [1.032; 1.146] (p = 0.002), Red Blood Cell (RBC) transfusion (units) with HR 1.056 [1.013; 1.102] (p = 0.01), MELD score with HR 1.020 [1.001; 1.040] (p = 0.036), RI < 0.55 on 1st post-transplant day with HR 1.651 [1.051, 2.594] (p = 0.029) and interval between venous and arterial reperfusion (min) with HR 1.003 [1.000; 1.007] (p = 0.039) were associated with decreased graft survival on the univariable analysis. These variables were pulled into a multivariate model (Table 5). RI on 1st post-transplant day was the only variable significantly associated with decreased graft survival on multivariable Cox Regression (HR 1.772 [1.050; 2.990], p = 0.032).
Table 6 shows the cause of death according to RI. Of the 59 patients with an RI < 0.55 on 1st post-transplant day, 25 (42.4%) patients died during the study period. In this group, primary nonfunction, sepsis and miscellaneous causes were the most common causes of death, each accounting for 4 (16%) deaths. Conversely, of the 250 patients with RI > 0.55 on 1st post-transplant day, 78 died during the study period. The most common cause of death was miscellaneous (n = 24, 30.8%) and disease recurrence (n = 17, 21.8%). No statistically significant difference in cause of death between the two groups was detected.