Faculty Bibliography

Tacrolimus is a mainstay medication for graft-versus-host disease (GVHD) prophylaxis in combination with other immunosuppressive agents. Achieving therapeutic tacrolimus levels is vital in preventing acute GVHD (aGVHD), while supratherapeutic levels may increase risk of toxicity and relapse. We performed a single center retrospective chart review including all adult patients post-allogeneic hematopoietic stem-cell transplantation who received initial tacrolimus continuous intravenous infusion for GVHD prophylaxis between June 1, 2017 and December 31, 2019. The primary outcome was the percent of patients with an initial therapeutic tacrolimus level, defined as 5-12 ng/mL, after empiric weight-based dosing at 0.02 mg/kg/day. Secondary outcomes included evidence of tacrolimus toxicity within seven days of initiation, incidence of aGVHD by day 100, and relapse after six months. An initial therapeutic level was achieved in 47% of patients with a median initial level of 12.4 ng/mL. Fifty-two percent of patients had supratherapeutic levels. No significant nephrotoxicity, hepatotoxicity, or neurotoxicity occurred within a week of starting tacrolimus or at neutrophil engraftment. Grade II-IV aGVHD by day 100 was observed in 22% of patients, and relapse after six months was found in 16% of patients. These results have led to consideration of an empiric 20% dose reduction to 0.016 mg/kg/day or an expanded initial tacrolimus target of 5-15 ng/mL as there was low aGVHD incidence and no increased risk of toxicity.

Glucose 6-phosphate dehydrogenase (G6PD) deficiency facilitates human coronavirus infection due to glutathione depletion. G6PD deficiency may especially predispose to hemolysis upon coronavirus disease-2019 (COVID-19) infection when employing pro-oxidant therapy. However, glutathione depletion is reversible by N-acetylcysteine (NAC) administration. We describe a severe case of COVID-19 infection in a G6PD-deficient patient treated with hydroxychloroquine who benefited from intravenous (IV) NAC beyond reversal of hemolysis. NAC blocked hemolysis and elevation of liver enzymes, C-reactive protein (CRP), and ferritin and allowed removal from respirator and veno-venous extracorporeal membrane oxygenator and full recovery of the G6PD-deficient patient. NAC was also administered to 9 additional respirator-dependent COVID-19-infected patients without G6PD deficiency. NAC elicited clinical improvement and markedly reduced CRP in all patients and ferritin in 9/10 patients. NAC mechanism of action may involve the blockade of viral infection and the ensuing cytokine storm that warrant follow-up confirmatory studies in the setting controlled clinical trials.

We conducted a retrospective review of thoracic transplant recipients (22 heart and 16 lung transplant recipients) prospectively enrolled in a single-center observational study of HCV NAT+ organ transplantation in HCV NAT- recipients. All recipients were treated with 8 weeks of glecaprevir-pibrentasvir (GP) for HCV viremia in addition to standard triple immunosuppression post-transplant. Thoracic transplant recipients of HCV NAT- organs were used as a control (24 heart and 22 lung transplant recipients). Our primary outcome was to assess the effect of GP on tacrolimus dose requirements. Secondary objectives included assessing drug interactions with common post-transplant medications, adverse effects, and the need to hold or discontinue GP therapy. The median tacrolimus concentration-to-dose (CDR) in the cohort was 184 (99-260) during GP therapy and 154 (78-304) over the first month after GP (p=0.79). Trends in median tacrolimus CDR were similar on a per-week basis and per-patient basis. In three instances, concomitant posaconazole and GP led to hyperbilirubinemia and interruption of posaconazole. GP therapy was held in one heart transplant recipient, and discontinued in another, due to unresolving hyperbilirubinemia. Utilization of GP to treat HCV viremia post-thoracic transplant is feasible and safe, but requires modifications to post-transplant pharmacotherapy and careful monitoring for adverse effects.

Study: Despite advances in design and hemocompatibility, pump thrombosis remains a significant cause of morbidity for patients implanted with durable left ventricular assist devices (LVAD). Pharmacologic fibrinolysis may be preferred as initial therapy because it obviates a surgical procedure. Yet, it historically has been associated with a significant risk of secondary intracerebral hemorrhage (ICH).
Method(s): We implemented a novel protocol to treat HVAD pump thrombosis and minimize risk of ICH that consisted of the following: initiation of a non-titrating heparin infusion at 500 units/hr; normalization of international normalized ratio (INR) by giving a flat dose of 1,000 units of four-factor prothrombin complex concentration (4F-PCC); and administration of alteplase as a 10 mg bolus followed by 40 mg given over 3 hours.
Result(s): Two patients underwent treatment with the above protocol for presumed HVAD pump thrombosis based on clinical signs of hemolysis and elevations of power on log-file analysis. One patient was 2 months from HVAD implant and the other 13 months. Both patients had subtherapeutic INR in the preceding weeks. Following administration of alteplase, log-file analysis demonstrated immediate resolution of power elevations (Fig. 1). Both patients had a subsequent rise in power requiring repeat alteplase dosing. No bleeding or thrombotic events occurred with treatment. One patient underwent heart transplant a month after treatment and is doing well; the second patient is stable on HVAD support 4 months following alteplase. Combining 4F-PCC to temporarily normalize the INR with repeat dosing of alteplase was effective at resolving HVAD pump thrombosis without bleeding complications and should be investigated further

BACKGROUND:The use of direct acting antivirals (DAA) has expanded transplantation from hepatitis C viremic donors (HCV-VIR). Our team has conducted an open-label, prospective trial to assess outcomes transplanting HCV-viremic hearts. Glecaprevir/Pibrentasvir (GLE/PIB) was our sole DAA. METHODS:Serial quantitative hepatitis C virus (HCV) RNA PCR was obtained to assess HCV viral titers. Between January 2018 to June 2019, a total of 50 recipients were transplanted. Of these, 22/50 (44%) were from HCV-VIR, the remaining 28 from non-viremic (HCV NON-VIR) donors. An 8 week course of GLE/PIB was initiated at 1 week post-transplant. RESULTS:There was no difference in demographic or clinical parameters between groups. All 22 recipients of HCV-VIR transplants became viremic. GLE/PIB was effective in decreasing viremia to undetectable levels by 6 weeks post-transplant in all patients. The median time to first undetectable HCV quantitative PCR was (4.3 weeks, IQR: 4-5.7 weeks). All patients demonstrated sustained undetectable viral load through 1 year follow up. There was no difference in survival at one year between HCV NON-VIR 28/28: (100%) vs. HCV-VIR 21/22 (95%) recipients. CONCLUSIONS:Our center reports excellent outcomes in transplanting utilizing hearts from HCV-VIR donors. No effect on survival or co-morbidity was found. An 8 week GLE/PIB course was safe and effective when initiated approximately 1 week post-transplant.

PURPOSE: Adequate pain control is essential following lung transplantation to reduce patient stress and minimize perioperative complications. Enhanced recovery after surgery (ERAS) protocols have demonstrated improvements in patient experience and reduced length of stay. However, the implementation of these protocols has not yet extended to the lung transplant population.
METHOD(S): We retrospectively reviewed all lung transplant recipients (LTR) at our institution from February 2018 to August 2019. An opioid-sparing, multimodal pain regimen was implemented that included preemptive analgesia with gabapentin and acetaminophen (APAP) pre-transplant; liposomal bupivacaine intercostal nerve block (INB) in the operating room; and a combination of APAP, gabapentin, and methocarbamol post-op with opioids given as indicated. Serratus anterior plane block was used for refractory pain.
RESULT(S): In total, we reviewed 48 LTR. The mean LAS was 43.74 and 21% were on mechanical ventilation or ECMO pre-transplant. Frequency of protocol adherence for each agent was as follows: liposomal bupivacaine INB (71%), APAP (100%), gabapentin (98%), methocarbamol (27%), and ketorolac (33%). Seven patients (15%) required a serratus plane block for refractory pain. Pain scores peaked at a median of 5 on postoperative day (POD) 1 and declined to a median of 3 by POD 3. By POD 4 only 54% of patients were still receiving opioids at a median of 15 mg oral morphine equivalents per day (IQR, 0-59). Only 3 patients were discharged on opioids and they were all on opioids pre-transplant. The median duration of mechanical ventilation was 1 day (IQR, 0.64-1.69) and 81% were extubated before 48 hours. The median hospital length of stay was 8 days (IQR, 6-15) and 30-day mortality was 0%.
CONCLUSION(S): Enhanced recovery and opioid-sparing pain protocols are feasible in LTR leading to minimal opioid use and acceptable pain scores. Outcomes with ERAS protocols should be compared to standard-of-care postoperative management.
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PURPOSE: Thoracic organ transplantation from Hepatitis C (HCV) viremic donors is a promising strategy due to curative therapies for HCV. Currently, there is no consensus on the best time to initiate HCV therapy relative to time of transplantation. We assessed the difference in magnitude of viremia and time to clearance in recipients of heart (HT) and lung (LT) transplant, based on timing of starting antiviral HCV therapy.
METHOD(S): From January 2018 to October 2019, 42 patients received thoracic organs from viremic donors. All recipients were treated with Mavyret (glecaprevir/pibrentasvir) for 8 weeks. HT recipients received therapy at the time of detectable viremia, while LT recipients were preemptively treated within 3 days post-transplant. HCV viral load was monitored by RT-PCR.
RESULT(S): 23 patients received HT (mean age 59 +/- 9 years) and 19 patients received LT (mean age 60 +/- 9 years). HCV serologic testing was performed in HT recipients at a mean of 7 +/- 1 days and in LT recipients at a mean of 4 +/- 3 days post-transplant. At the time of testing, all HT and 14 LT patients had detectable viremia. Five LT patients never developed viremia. The mean viral load f HT was 4.5 logIU/mL and for LT was 1.6 logIU/ml. Viremia clearance was obtained at a mean of 28 +/- 13 days in HT and 21+/-11 days in LT recipients (p=0.13) (Fig). The mean time to HCV antibody (AB) clearance was 130 +/- 145 days in HT and 225 +/- 103 days in LT recipients (p=0.058). There was no correlation between the 2 groups in either the duration of viremia or HCV AB clearance.
CONCLUSION(S): Our study suggests that the magnitude and conversion to detectable viremia depends on the time of initiation of HCV therapy relative to time of transplant with complete conversion to HCV viremia in the HT group. Interestingly, there was no significance in time to viremia or HCV AB clearance between the two groups. This may be an organ specific response, but larger sample size studies need to be conducted to define the optimal time of starting HCV therapy.
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PURPOSE: Azole antifungals are commonly prescribed for fungal prophylaxis (ppx) following lung transplant, but have many side effects and drug interactions. Isavuconazole, a new broad-spectrum azole antifungal, may obviate these issues.
METHOD(S): We retrospectively reviewed all lung transplant recipients (LTR) from February 2018 through September 2019 who received either ISA or POS for fungal ppx for 3 months post-transplant. Prior to February 2019 all patients received POS for ppx. Starting February 2019, POS was replaced by ISA at standard dosing. All patients received basiliximab induction and standard triple immunosuppression post-transplant. Surveillance bronchoscopies were performed at 1, 3, 6, and 12 months post-transplant.
RESULT(S): In total, we reviewed 24 LTR who received ISA and 29 who received POS. Baseline characteristics were similar between groups. Median duration of follow-up was significantly shorter for the ISA group (137 vs. 340 days, p<0.01). Breakthrough fungal infections occurred in 3 (13%) and 2 (7%) patients in the ISA and POS groups, respectively (p=0.65). All ISA patients developed oropharyngeal candidiasis; in the POS group there was one each of candida empyema and mold colonization. Post-ppx fungal infections occurred in 1 (4%) and 5 (17%) patients in the ISA and POS groups, respectively (p=0.20). All of these were mold colonization except for one case of oropharyngeal candidiasis. There was no difference between fungal-infection free survival based on Kaplan-Meier analysis (p=0.69). POS was held in two cases and discontinued in 1 patient due to a drug interaction causing hepatotoxicity compared to zero patients receiving ISA (p=0.24).
CONCLUSION(S): Breakthrough fungal infections were similar between LTR receiving ISA or POS for fungal ppx. Longer follow-up of ISA patients is needed for definitive comparison of long-term infection risk. POS was discontinued in more patients due to drug interactions. ISA is a reasonable choice for primary fungal ppx in LTR.
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The approach to monitoring anticoagulation in adult patients receiving heparin on extracorporeal membrane oxygenation (ECMO) support is controversial. The objective of this study was to compare the correlation between anti-Xa and aPTT with heparin dose and to describe their association with clinical events in adult ECMO patients. We conducted a retrospective single-center study of 34 adult ECMO patients whose heparin was monitored by anti-Xa or aPTT. The heparin dose-to-assay correlation coefficient was 0.106 for aPTT and 0.414 for anti-Xa (p < 0.001). Major thrombotic and hemorrhagic events occurred in 14.7% and 26.5% of patients, respectively. The median anti-Xa in patients who experienced a major thrombotic event was 0.09 (0.06-0.25) IU/mL compared with 0.36 (0.26-0.44) IU/mL in patients who did not (p = 0.031), whereas the median aPTT did not differ between these groups. The maximum aPTT in patients who experienced a major bleed was 96.9 (76.0-200) seconds compared with 63.5 (44.4-98.6) seconds in patients who did not (p = 0.049), whereas the maximum anti-Xa did not differ between these groups. Monitoring both anti-Xa and aPTT may be warranted to safely provide understanding of pure heparin activity as well as underlying bleeding diatheses in adult ECMO patients.