SATA

Society for the Advancement of Transplant Anesthesia

Article of the Month

Article of the Month May 2022

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Intraoperative Intracardiac Thrombus in Liver Transplant: A 9-year Retrospective Review Focusing on Treatment and Outcomes

 

“This study characterizes incidence and outcomes surrounding intracardiac thrombosis (ICT) during liver transplantation over 9 years at a single center before and after the routine use of transesophageal echocardiography (TEE). Adult liver transplantation patients from 2011 to 2020 were divided into eras based on routine TEE use. ICTs were identified by querying anesthetic records for search terms. Descriptive statistics included counts and proportions for baseline recipient, donor, intraoperative, and postoperative characteristics. Outcome data were based on date of hospital discharge and date of death. The incidence of ICT increased in the TEE era (2016-2020) compared with the pre-TEE era (2011-2015; 3.7% [25/685] vs. 1.9% [9/491]; p < 0.001). Patients with ICT had significantly higher Model for End-Stage Liver Disease-sodium (MELD-Na) scores, pretransplant hospitalization, malignancy, drug-induced liver injury, hypertension, deep vein thrombosis, reperfusion syndrome, transfused platelets and cryoprecipitate, and use of hemostatic medications. A higher proportion of patients in the ICT group underwent simultaneous liver-kidney transplantation. The patients with ICT were similar, except patients in the pre-TEE era had higher MELD-Na scores and incidences of hepatitis C virus and lower incidences of encephalopathy. In the pre-TEE era, all ICTs presented as intraoperative cardiac arrest, and the 30-day mortality in the setting of ICT was 66.7% (6/9). During the TEE era, 80% of ICTs were diagnosed incidentally or attributed to hemodynamic instability (p = 0.002). The 30-day mortality rate was 36% (9/25) in the TEE era (p = 0.25). ICT incidence increased in the TEE era, yet the mortality rate was lower, suggesting that routine intraoperative TEE may lead to the early detection of ICT prior to hemodynamic collapse.”

 

Comments made by Cara Crouch, MD  

Intracardiac thrombus (ICT) is a rare but devastating complication during orthotopic liver transplantation (OLT). This study evaluates the incidence of ICT before and after TEE use during OLT became standard at a single institution. As expected, there was a higher incidence of ICT found once TEE use became standard practice, however, an important point to note from this article is the lower mortality rate during the TEE era (36% vs 66.7% in the pre-TEE era). The authors point out that earlier detection of thrombi via TEE may allow for more prompt treatment prior to the progression to full cardiovascular collapse.

This article also provides a thorough review of a single institutions experience with ICT over a 9-year period and the authors provide extensive baseline characteristics of the patients who developed this complication. The authors found that patients undergoing simultaneous liver-kidney transplant (SLK) seemed to have a higher incidence of ICT, though the use of intraoperative renal replacement therapy (non-heparinized circuit) was higher in patients undergoing SLK and the authors question if this may be the reason. Patients who experienced ICT were more likely to have post-reperfusion syndrome, platelet and cryoprecipitate transfusion, as well as administration of recombinant factor VII, tranexamic acid and desmopressin. This article offers good support for the standardization of intraoperative TEE use in patients undergoing liver transplantation. However, it is understood that this may not be feasible at some institutions, the authors also highlight several intraoperative factors that appear to be correlated with the development in ICT. This information may prove useful in helping to determine which patients may benefit from TEE probe placement given that they are higher risk for this potentially fatal complication.

References:

  1. Fagelman E, Wang R, Tomlinson A, Romano D, Schlichting N, Zerillo J, DeMaria S, Smith N. Intraoperative Intracardiac Thrombus in Liver Transplant: A 9-year Retrospective Review Focusing on Treatment and Outcomes. Liver Transplantation. April 2022.

March Article of the Month 2022

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Perioperative Normal Saline Administration and Delayed Graft Function in Patients Undergoing Kidney Transplantation: A Retrospective Cohort Study

Abstract

“Background: Perioperative normal saline administration remains common practice during kidney transplantation. The authors hypothesized that the proportion of balanced crystalloids versus normal saline administered during the perioperative period would be associated with the likelihood of delayed graft function.

Methods: The authors linked outcome data from a national transplant registry with institutional anesthesia records from 2005 to 2015. The cohort included adult living and deceased donor transplants, and recipients with or without need for dialysis before transplant. The primary exposure was the percent normal saline of the total amount of crystalloids administered perioperatively, categorized into a low (less than or equal to 30%), intermediate (greater than 30% but less than 80%), and high normal saline group (greater than or equal to 80%). The primary outcome was the incidence of delayed graft function, defined as the need for dialysis within 1 week of transplant. The authors adjusted for the following potential confounders and covariates: transplant year, total crystalloid volume, surgical duration, vasopressor infusions, and erythrocyte transfusions; recipient sex, age, body mass index, race, number of human leukocyte antigen mismatches, and dialysis vintage; and donor type, age, and sex.

Results: The authors analyzed 2,515 records. The incidence of delayed graft function in the low, intermediate, and high normal saline group was 15.8% (61/385), 17.5% (113/646), and 21% (311/1,484), respectively. The adjusted odds ratio (95% CI) for delayed graft function was 1.24 (0.85 to 1.81) for the intermediate and 1.55 (1.09 to 2.19) for the high normal saline group compared with the low normal saline group. For deceased donor transplants, delayed graft function in the low, intermediate, and high normal saline group was 24% (54/225 [reference]), 28.6% (99/346; adjusted odds ratio, 1.28 [0.85 to 1.93]), and 30.8% (277/901; adjusted odds ratio, 1.52 [1.05 to 2.21]); and for living donor transplants, 4.4% (7/160 [reference]), 4.7% (14/300; adjusted odds ratio, 1.15 [0.42 to 3.10]), and 5.8% (34/583; adjusted odds ratio, 1.66 [0.65 to 4.25]), respectively.

Conclusions: High percent normal saline administration is associated with delayed graft function in kidney transplant recipients.”

Comments by Scott Byram M.D.

Summary:

This article1 from Anesthesiology was chosen because of the extremely common and often contentious debate on choice of crystalloid during renal transplantation.  Many anesthesiologists prefer to avoid lactated ringers or PlasmaLyte (Baxter International Inc., USA) in favor of normal saline, because of the perceived risk of perioperative hyperkalemia after high volume resuscitation with potassium-containing crystalloids.  Conversely, several studies have actually shown MORE hyperkalemia with normal saline administration due to hyperchloremic acidosis and subsequent extracellular potassium shift. 

This study was a retrospective database review of 2515 patients who received a renal transplant from 2005-2015 at a single institution.  The authors grouped patients into 3 groups based on percent of fluid resuscitation consisting of normal saline (low ≤30%, intermediate 30-80%, and high ≥80%).  The primary outcome variable was delayed graft function as defined by need for hemodialysis within 1 week of transplantation. The results of this study showed the incidence of delayed graft function was 15.8%, 17.5%, and 21% respectively in the low, intermediate, and high saline groups.   This association was still seen regardless of donor type (deceased vs. living); however, the magnitude was much greater in deceased donors.   The authors speculated that the delayed graft function in the high saline group was due to a high chloride load causing decreased renal perfusion and glomerular filtration rate, which has been previously demonstrated in animal and volunteer studies.  In this retrospective cohort study, a high percentage of normal saline administration was associated with delayed graft function in renal transplant recipients.

References

Kolodzie K, Cakmakkaya OS, Boparai ES, Tavakol M, Feiner JR, Kim MO, Newman TB, Niemann CU. Perioperative Normal Saline Administration and Delayed Graft Function in Patients Undergoing Kidney Transplantation: A Retrospective Cohort Study. Anesthesiology. 2021 Oct 1;135(4):621-632. doi: 10.1097/ALN.0000000000003887. Erratum in: Anesthesiology. 2022 Jan 1;136(1):251. PMID: 34265037.

April Article of the Month 2022

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Outcome of Liver Transplants Using Donors After Cardiac Death with Normothermic Regional Perfusion.

Abstract:

Background and aims: The incorporation of normothermic regional perfusion (NRP) to donors after cardiac death (DCD) allows the recovery of liver grafts without the deleterious effects on graft survival the super-rapid technique may cause. The aim of the present report is to determine if the use of NRP in Maastricht type III DCD donors achieves short- and medium-term results comparable to donors after brain death (DBD).

Patients and methods: This is an observational cohort study including 117 liver transplants executed between November 2016 and April 2021, divided into NRP (n = 39) and DBD (n = 78).

Results: Donors were younger in the NRP group (NRP 52 vs DBD 59.4 years; P < .005). Liver recipients in each study group were of similar age and severity of liver disease, although the predominant transplant indication in the NRP group was hepatocellular carcinoma. No differences in ischemia times were found. The incidence of early allograft disfunction and primary nonfunction was balanced between NRP and DBD. Eight patients required retransplant, all of them in the DBD group. No differences were found in biliary complications (NRP 12% vs DBD 5%; P = .104). Ischemic cholangiopathy affected a single DBD patient. Graft survival’s Kaplan Meier curve shows a better outcome in the NRP group, although the difference did not reach significance (P = .075).

Conclusions: The incorporation of perfusion machines, and specifically the NPR in situ, converts suboptimal liver grafts such as DCD into organs comparable to DBDs.

Comments made by Cale Kassel M.D., FASA  

Summary:

In this observational cohort study the authors compared the use of normothermic regional perfusion (NRP) in donation after cardiac death (DCD) donors to donation after brain death donors (DBD). A total of 117 liver transplants were included, 39 in the NRP group and 78 in the DBD group.

Donors for the two groups were largely similar we a few exceptions. Donor age was lower in the NRP group (52 vs. 59.4; p = 0.005). While the number of days in the ICU was higher in the NRP group (7.21 vs. 2.62; p = 0.000), the use of vasopressor support was higher in the DBD group (86.4% compared to 35.1%). 

Recipient differences were similar for MELD scores for the NRP and DBD groups. (14.48 vs. 16.14; p = 0.392). The authors noted differences in indication for transplant between the two groups. For DBD, alcoholic cirrhosis was the most common indication followed by hepatocellular carcinoma. In the NRP group, hepatocellular carcinoma was the most common indication. 

No primary endpoint was noted but overall survival was similar between the two groups. One year survival for the NRP group as 94% compared to 84% in the DBD group and at three years, survival was 71% for the NRP group and 75% for the DBD group. While the Kaplan-Meier curve showed better survival with the NRP group, this did not reach statistical significance (p = 0.075). Biliary complications were not statistically different between the two groups (NRP at 12%, DBD at 5%). Early allograft dysfunction, primary non-function, and acute kidney injury were similar between the two groups. 

With constant need for donor organs, new ways to procure organs for transplant warrant consideration. Early evidence raised concerns on the rate of biliary complications with DCD donors that may limit their usefulness. However, NRP or machine perfusion appears to offer promise for DCD organ use while also minimizing biliary issues post-operatively. This small study adds to the body of evidence supporting the use of NRP for DCD organs. 

References:

Rodriguez RP, Perez BS, Daga JAP, et al. Outcome of Liver Transplants Using Donors After Cardiac Death with Normothermic Regional Perfusion. Transplantation proceedings 2022;54(1):37-40.

February 2022 – Article of the Month

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Is Obesity Associated with Better Liver Transplant Outcomes? A Retrospective Study of Hospital Length of Stay and Mortality Following Liver Transplantation. Anesthesia and Analgesia. 2022.

Abstract:

Background: The rise in obesity in the United States, along with improvements in antiviral therapies, has led to an increase in the number of obese patients receiving liver transplants. Currently, obesity is a relative contraindication for liver transplant, although exact body mass index (BMI) limits continue to be debated. Studies conflict regarding outcomes in obese patients, while some argue that BMI should not be used as an exclusion criterion at all. Therefore, this retrospective study-utilizing a large national database-seeks to elucidate the association between recipient BMI and hospital length of stay and mortality following liver transplant.

Methods: A retrospective study was conducted using the United Network for Organ Sharing Standard Transplant Analysis and Research database. Fine-Gray competing risk regressions were used to explore the association between BMI and rate of discharge, which varies inversely with length of stay. In our model, subdistribution hazard ratio (SHR) represented the relative change in discharge rate compared to normal BMI, with in-hospital death was considered as a competing event for live discharge. Cox proportional hazard models were built to assess the association of BMI category on all-cause mortality after liver transplantation. Cluster-robust standard errors were used in all analyses to construct confidence intervals.

Results: Within the final sample (n = 47,038), overweight (≥25 and <30 kg/m2) patients comprised the largest BMI group (34.7%). The competing risk regression model showed an association for increased length of stay among underweight (SHR = 0.82, 95% confidence interval [CI], 0.77-0.89; P < .001) and class 3 obesity patients (SHR = 0.88, 95% CI, 0.83-0.94; P < .001), while overweight (SHR = 1.05, 95% CI, 1.03-1.08; P < .001) and class 1 obesity (SHR = 1.04, 95% CI, 1.01-1.07; P = .01) were associated with decreased length of stay. When the sample excluded patients with low pretransplant functional status, however, length of stay was not significantly shorter for overweight and obesity class 1 patients. Cox proportional hazard models demonstrated increased survival among overweight, class 1 and class 2 obesity patients and decreased survival among underweight patients.

Conclusions: Our results provide evidence that overweight and obesity class 1 are associated with decreased length of stay and mortality following liver transplant, while underweight and obesity class 3 are associated with prolonged length of stay. Pretransplant functional status may contribute to outcomes for overweight and class 1 obese patients, which necessitates continued investigation of the isolated impact of BMI in those who have had a liver transplant.

Comments made by Cale Kassel M.D., FASA  

Summary:

In this retrospective study1 examining obesity in liver transplant patients, the authors utilized data from the Scientific Registry of Transplant Recipients (SRTR) to compare obesity class and hospital length of stay (LOS) and mortality. With nonalcoholic steatohepatitis (NASH) set to become the leading indication for LT, providers must consider the risks of transplantation in obese patients. With conflicting data on the risk of obesity in LT, this is usually a center-specific guideline on listing patients with elevated BMI. A total of 47,038 patients were reviewed and divided into 6 groups (underweight, normal, overweight, obese I, obese II, and obese III).

Compared to normal weight patients, hospital LOS was lower in the overweight and class I obesity group while it was longer in the obese III and underweight groups. Further risk analysis that excluded patients with hospitalization prior to transplant, functional status < 50%, mechanical ventilation still demonstrated longer LOS with underweight and obese III groups.

At 90 days, survival was lowest in the underweight and class III obesity group of patients (95.5%, 94.1% respectively). Survival at 1 year and 10 years were lowest in the underweight group of all groups studied. Interestingly, the class I obesity group had the best 1-year and overall survival by the unadjusted Kaplan-Meier model.

The retrospective nature of the study and the presence of ascites are both limitations interpreting the data. Factoring in ascites in the body weight calculation can be challenging and may have led to overrepresentation of obese patients in this study.

Ultimately, the authors found shorter LOS in overweight and class I obesity. Both underweight and class III obesity had longer LOS. Further research into this topic is needed to evaluate the role of functional status in obesity and outcomes. For programs looking to identify specific cutoffs, the authors suggest, based on their findings, that many centers may benefit from a BMI cutoff of > 40 kg/m2.  It should be noted that both the AASLD and AST consider class III obesity as a contraindication for LT. The EASL suggests careful evaluation of patients with a BMI > 35 kg/m2.

References:

  1. Du AL, Danforth DJ, Waterman RS, Gabriel RA. Is Obesity Associated with Better Liver Transplant Outcomes? A Retrospective Study of Hospital Length of Stay and Mortality Following Liver Transplantation. Anesthesia and Analgesia. 2022.

January 2022 – Article of the Month

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Postreperfusion syndrome in liver transplantation: Outcomes, predictors, and application for recipient selection. Clinical Transplantation. 2022.

“Background: This study aimed to identify risk factors for postreperfusion syndrome (PRS) and its impact on LT outcomes.

Methods: Data analysis was performed in 1021 adult patients undergoing donation after brain death (DBD) LT to identify PRS incidence, the risk factors for PRS development, and its impact on LT outcomes.

Results: The overall incidence of PRS was 16.1%. Independent risk factors for PRS included donor age (odds ratio (OR) 1.01, P = .02), donor body mass index (BMI) (OR 1.04, P = .003), moderate macrosteatosis (OR 2.48, P = .02), and cold ischemia time (CIT) (OR 1.06, P = .02). On multivariable analysis for 30-day graft failure, PRS (hazard ratio (HR) 3.49; P < .001) and Model for End-stage Liver Disease (MELD) score (HR 1.01; P = .05) were independent risk factors. Patients were categorized into four distinct groups based on PRS risk groups and MELD groups, which showed different 1-year graft survival (P < .001). There were comparable outcomes between low PRS risk – high MELD and high PRS risk – low MELD group (P = .33).

Conclusions: Donor age, donor BMI, moderate macrosteatosis, and CIT were identified as risk factors for the development of PRS in LT using DBD grafts. PRS risk evaluation may improve donor-to-recipient matching based on their MELD scores.”

Comments made by Cara Crouch, MD  

This article conducted a retrospective review of all adult DBD liver transplants from a single center over a 15-year period, excluding patients who received multi-organ transplants, DCD grafts, split grafts, LDLT, retransplant and patients who were transplanted due to acute liver failure, to identify risk factors for the development of postreperfusion syndrome (PRS). The authors also reviewed outcomes and offer suggestions for donor/recipient matching to reduce the incidence of PRS. The authors defined PRS as “a >30% decline in mean arterial pressure (MAP) from baseline within 5 minutes of graft reperfusion and lasting at least 1 minute.” A total of 1021 cases were reviewed and the overall incidence of PRS was found to be 16.1%.

The authors found no recipient factors that were statistically significant for an association with PRS. Four donor factors were found to be independently associated with PRS: donor age, donor BMI, moderate macrosteatosis (30-60%) and cold ischemia time. The authors used this data to develop a PRS risk sore used to categorize patients as either low or high PRS risk.

Patients also underwent further risk stratification, low ( 25) vs. high (>25) MELD, in combination with low vs. high PRS risk to analyze graft and patient survival. The occurrence of PRS was found to be associated with worse short-term graft and patient outcomes but not long-term outcomes. When PRS risk and MELD score were combined, it was found that patients with high MELD and high PRS risk factors had poor outcomes. The authors suggest that identifying the PRS risk factors and utilizing the risk score may allow for more optimal donor/recipient matching to improve overall outcomes.

References:

1. Bekki Y, Myers B, Wang R, Smith N, Zerillo J, Rocha C, Tabrizian P, Moon J, Arvelakis A, Facciuto M, DeMaria S, Florman S. Postreperfusion syndrome in liver transplantation: Outcomes, predictors and application for recipient selection. Clinical Transplantation. 2022.

International consensus recommendations for anesthetic and intensive care management of lung transplantation

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“International consensus recommendations for anesthetic and intensive care management of lung transplantation. An EACTAIC, SCA, ISHLT, ESOT, ESTS, and AST approved document.”

Nandor Marczin, MD, PhD, Eric E.C. de Waal, MD, PhD, Peter M.A. Hopkins, MD, Michael S. Mulligan, MD, Andre Simon, MD, PhD, Andrew D. Shaw, MB, FRCA, FRCPC, FFICM, Dirk Van Raemdonck, MD, PhD, Arne Neyrinck, MD, PhD, Cynthia J. Gries, MD, MS, Lars Algotsson, MD, PhD, Laszlo Szegedi, MD, PhD, and Vera von Dossow, MD, Task force Chairs and Writing Group (exclusive of the consensus developing and coordinating group members): Aidan Burrell, MBBS, PhD; Paula Carmona, MD, PhD; Donna Greenhalgh, MB, ChB, FRCA; Dominik Hochter, MD; Bessie Kachulis, MD; Christopher S. King, MD; Marc J. Licker, MD; David R. McIlroy, MBBS, MClinEpi, MD, FANZCA; Priya Nair, MBBS, MD, FCICM, PhD; Daniela Pasero, MD, MSc; David Pilcher, MBBS, MRCP, FCICM, FRACP; Steffen Rex, MD, PhD; David Royston, FRCA; Peter Slinger, MD, FRCPC; Franco Valenza, MD; Chris Walker, MBBS, FRCA, FFPMRCA, FFICM. Consensus members (exclusive of the consensus developing and coordinating group or co-chairs and writing group members): Antonio Arcadipane, MD; Oliver Bastien, MD, PhD; Joseph A. Bekkers, MD, PhD; Dominique Bettex, MD; Francesca Caliandro, MD; Erika Dal Checco, MD; Robert Duane Davis, MD; Goran Dellg- ren, MD, PhD; Andreas Espinoza, MD, PhD; Marie Louise Felten, MD; Paolo Feltracco, MD; Marc Fischler, MD; Linda J Fitzgerald, PharmD, BCPS; Ana Flo Forner, MD; Isabel Fragata, MD; Ana Gonzalez Roman, MD, PhD, MBA; Paul Harris, MBChB, FRCA, FFICM, RCPathME; Matthias Hommel, MD, MBA; Nicholas J. Lees, FRCA, EDIC, FFICM; Morgan Le Guen, MD, PhD; Marc Leone, MD, PhD; Thierry Lepoivre, MD; Carlo Marcucci, MD; Sabina Martelli, MD; Mir- eille Michel-Cherqui, MD; Ulrich Molitoris, MD; Philippe Montravers, MD, PhD; Roberto Mosca, MD; Barbora Parizkova, MD, FRCA; Mahesh Prabhu, MD, FRCA, FFICM; Francesco Pugliese, MD; Sanjeev M. Raman, MBBS, MD; Cristina Ramos, MD; Vito Marco Ranieri, MD; Maria I. Real, MD, PhD; Sven-Erik Ricks- ten; Ana Gonzalez Roman, MD, PhD, MBA; Bertrand Rozec, MD, PhD; Shiva M. Sale, MBBS, MD, FASE; Juan F. Sanchez, MD, FCCP; Johanna Schwarzenberger, MD; Sema Turan, MD; Kamen Valchanov, BSc, MD, FRCA, FFICM; Vincent G. Valentine MD, FCCP; Peter von Homeyer, MD, FASE; Alain Vuylsteke, BSc, MA, MD, (FRCA, FFICM); Thomas Weig, MD; Iratxe Zarragoikoetxea, MD, PhD; Sebastian Zenz, MD. Independent Reviewers: Pierre-Emmanuel Falcoz MD; Ilhan Inci, FEBTS; Andrew Roscoe, FRCA; Mert Senturk, MD.
J Heart Lung Transplant 2021 Nov;40(11):1327-1348.

This quarter’s editorial is taking a step off the beaten path. Last month the Journal of Heart and Lung Transplantation published, what I believe to be, a groundbreaking international multidisciplinary document for perioperative care of lung transplant recipients. This document acknowledges that anesthetic and intensive care management impacts long term outcomes in lung transplant recipients. It offers a combination of published data and expert opinion for guidance and is the first major consensus document to specifically address anesthetic care for lung transplantation.

Key themes include the inclusion of anesthesiologists and intensivists in the selection of lung transplant recipients, use of echocardiography intraoperatively, indications for intraoperative rescue mechanical support, timing of ECMO wean, and strategies for the prevention of primary graft dysfunction. This is a strong document. I hope you give it a read.

Barbara Wilkey, MD

Evaluation with Transesophageal Echocardiography of Pulmonary Artery Anastomoses during Orthotopic Lung Transplantation

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Michael Curtis, MD

University of California, San Francisco

Introduction

Lung transplantation remains only a class IIb indication for intraoperative monitoring via transesophageal echocardiography (TEE) in existing guidelines.1 However, some have suggested that TEE should become routine during these procedures2, given the multiple and varied impacts to the cardiovascular system throughout such a case (e.g., pulmonary artery clamping, reperfusion injury, air embolization, etc.) TEE may also be able to quickly detect obstruction at the pulmonary artery (PA) anastomosis at the pulmonary arteries and making immediate intraoperative revision possible if needed. While no society guidelines exist for diagnosing such a life-threatening complication on intraoperative TEE, there are many recommendations one may use to guide their evaluation.

Incidence and Related Complications

Obstruction of a pulmonary artery anastomosis is rare – it was reported in approximately 3% of lung transplantations reviewed in a recent meta-analysis by Kumar et al.3 A multitude of etiologies have been implicated, including donor-recipient size mismatch, external compression from surrounding tissue, twisting and/or kinking, thrombosis, and suture obstruction.3,4 Those with restrictive lung disease and females also appear to be at higher risk of PA obstruction. Finally, obstruction at the pulmonary arterial sites is generally accepted to be more common than at their venous counterparts, which is thought to result from differences in the surgical technique required at the different anastomotic sites.4,5

            Although relatively rare, such obstruction at a pulmonary artery anastomosis cannot be taken lightly: once diagnosed, the rate of mortality approaches nearly 25%.3 There are also associated complications that may result, such as graft failure, persistent hypoxemia, prolonged need for mechanical ventilation, and right-heart failure.3,5 These potentially devastating consequences highlight the importance of having high index of suspicion for such a lesion. For example, early clinical signs may be hemodynamic instability, pulmonary hypertension, a diminished capnography tracing, or unexplained hypoxemia or acidosis should all be concerning to providers.6,7

Role of Transesophageal Echocardiography

            With regards to objective testing, pulmonary angiography is regarded as being the gold standard for diagnosis of stenosis at the pulmonary artery anastomosis, given its imaging quality and ability to immediately intervene on the findings with catheter-based techniques.4 However, intraoperative TEE is able to provide much earlier insight into possible complications with an anastomotic site, allowing for immediate surgical revision and avoidance of any related post-operative complications.

            Unfortunately, consensus guidelines on the diagnosis of obstruction at a PA anastomosis by echocardiography do not exist. However, multiple measures have been proposed (Table 1), including the intraluminal narrowing of the pulmonary artery graft to 75% or less of the diameter of the native, ipsilateral PA, as put forth by Hausmann et al. in their 1992 publication.8 Other suggested measures that should be concerning are a mean velocity through the pulmonary artery of 2.6 m/s or greater, a gross PA diameter of less than  0.8 cm, the presence of turbulent flow on color doppler, and elevated pressure gradients across the anastomosis.3 What precisely constitutes an elevated gradient at the PA anastomosis itself lacks wide-agreement, though some having put forth using the American Society of Echocardiography (ASE) guidelines for pulmonary valve stenosis as a guide7, while others recommend that gradients should be of concern once 57 mm Hg or higher.3

            Interrogation of related structures by echo, such as the pulmonary veins, may also provide hints as to the functioning of the pulmonary arteries. For example, impaired flow as demonstrated by doppler (e.g., blunted S or D waves) or thrombosis due to stasis in the ipsilateral pulmonary veins may also be concerning for PA anastomotic obstruction.7 Similarly, evidence of increased perfusion through the contralateral pulmonary veins (e.g., increased velocities) may be a sign that a significantly greater proportion of right-heart output is going through one pulmonary artery due to the other being obstructed.

            Unfortunately, evaluation by the pulmonary arteries with TEE is inherently limited by anatomy. For example, the relative inability to evaluate the left pulmonary artery due to interference from the adjacent left mainstem bronchus. The relative orientation of the pulmonary arteries to the echo probe may also make it challenging to line up a doppler beam and obtain accurate velocities or pressure gradients. If concerned, other options that may be used intraoperatively include epipulmonary artery ultrasonography (i.e., direct, external contact with an ultrasound probe manipulated by surgical team), which one study has shown to be superior for imaging the left pulmonary artery than TEE itself.9 The surgeon may also directly cannulate the pulmonary artery of concern and measure a true pressure gradient by pullback technique.

Post-Operative Endovascular Interventions

Given that intraoperative diagnosis by TEE can be challenging, and that nearly 75% of patients diagnosed with PA obstruction post-operatively require some sort of procedural intervention3, it is fortunate that options exist now outside of open surgical techniques. For example, multiple reports of successful endovascular stenting have been published.10-12 Although balloon angioplasty alone is regarded as less useful in high-grade stenosis due to arterial elastic recoil10, it has still been shown to be successful in some cases.13

Conclusion

Although use of intraoperative TEE is not yet the standard of care during lung transplantation, it may provide information both critical to the hemodynamic management of the patient, as well as possible complications in the surgical procedure. Specifically, obstruction at a pulmonary artery anastomosis – a rare complication with high morbidity and mortality – may be caught early enough with thorough echocardiographic investigation to revise intraoperatively. However, it is important to remember inherent limitations of TEE prevent it from being a panacea for lesions at this location, and that sometimes it must be supplemented with alternative intraoperative or post-operative techniques when there is sufficient concern.

 

Table 1 – Signs Suggestive of Pulmonary Artery Anastomosis Obstruction on Transesophageal Echocardiography (TEE)
Gross Inspection of the Pulmonary Artery ·      Presence of an obstructive mass (e.g., thrombus)
Intraluminal Diameter ·      ≤ 75% of the native, ipsilateral pulmonary artery

·      < 0.8 cm intraluminal diameter
Pulmonary Artery Mean Velocity ·      ≥ 2.6 m/s
Color Doppler ·      Evidence of turbulent flow
Peak Pressure Gradient ·      No widespread agreement – however, suggestions to use gradients ≥ 57 mm Hg or ASE guidelines for grading pulmonary valve stenosis (i.e., mild < 36 mm Hg, moderate 36-64 mm Hg, and severe > 64 mm Hg)14 as a framework

 
Ipsilateral Pulmonary Veins ·      Evidence of diminished flows (e.g., blunted S or D waves) or stasis (e.g., presence of thrombus)

 
Contralateral Pulmonary Veins ·      Evidence of significantly increased flows (e.g., elevated velocities)

 

* American Society of Echocardiography (ASE)

 

 

 

 

References

  1. Cheitlin MD, Armstrong WF, Aurigemma GP, Beller GA, Bierman FZ, Davis JL, et al. ACC/AHA/ASE 2003 guideline update for the clinical application of echocardiography: summary article: a report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines (ACC/AHA/ASE Committee to Update the 1997 Guidelines for the Clinical Application of Echocardiography). Circulation. 2003;108(9):1146-62. Epub 2003/09/04. doi: 10.1161/01.CIR.0000073597.57414.A9. PubMed PMID: 12952829.
  2. Iyer MH, Bhatt A, Kumar N, Hussain N, Essandoh MK. Transesophageal Echocardiography for Lung Transplantation: A New Standard of Care? J Cardiothorac Vasc Anesth. 2020;34(3):741-3. Epub 2019/11/11. doi: 10.1053/j.jvca.2019.10.025. PubMed PMID: 31706852.
  3. Kumar N, Hussain N, Kumar J, Essandoh MK, Bhatt AM, Awad H, et al. Evaluating the Impact of Pulmonary Artery Obstruction After Lung Transplant Surgery: A Systematic Review and Meta-analysis. Transplantation. 2021;105(4):711-22. Epub 2021/03/25. doi: 10.1097/TP.0000000000003407. PubMed PMID: 33760790.
  4. Siddique A, Bose AK, Ozalp F, Butt TA, Muse H, Morley KE, et al. Vascular anastomotic complications in lung transplantation: a single institution’s experience. Interact Cardiovasc Thorac Surg. 2013;17(4):625-31. Epub 2013/06/22. doi: 10.1093/icvts/ivt266. PubMed PMID: 23788195; PubMed Central PMCID: PMCPMC3781793.
  5. Clark SC, Levine AJ, Hasan A, Hilton CJ, Forty J, Dark JH. Vascular complications of lung transplantation. Ann Thorac Surg. 1996;61(4):1079-82. Epub 1996/04/01. doi: 10.1016/0003-4975(96)00003-3. PubMed PMID: 8607660.
  6. Tan Z, Roscoe A, Rubino A. Transesophageal Echocardiography in Heart and Lung Transplantation. J Cardiothorac Vasc Anesth. 2019;33(6):1548-58. Epub 2019/02/03. doi: 10.1053/j.jvca.2019.01.005. PubMed PMID: 30709594.
  7. Abrams BA, Melnyk V, Allen WL, Subramaniam K, Scott CD, Mitchell JD, et al. TEE for Lung Transplantation: A Case Series and Discussion of Vascular Complications. J Cardiothorac Vasc Anesth. 2020;34(3):733-40. Epub 2019/10/02. doi: 10.1053/j.jvca.2019.09.005. PubMed PMID: 31570240.
  8. Hausmann D, Daniel WG, Mugge A, Heublein B, Hamm M, Schafers HJ, et al. Imaging of pulmonary artery and vein anastomoses by transesophageal echocardiography after lung transplantation. Circulation. 1992;86(5 Suppl):II251-8. Epub 1992/11/01. PubMed PMID: 1424008.
  9. Felten ML, Michel-Cherqui M, Sage E, Fischler M. Transesophageal and contact ultrasound echographic assessments of pulmonary vessels in bilateral lung transplantation. Ann Thorac Surg. 2012;93(4):1094-100. Epub 2012/03/06. doi: 10.1016/j.athoracsur.2012.01.070. PubMed PMID: 22387146.
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MitraClip in secondary mitral regurgitation as a bridge to heart transplantation: 1 year outcomes from the International MitraBridge

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Cardiothoracic Transplant Anesthesia Article of the Month

Godino C, Munafo A, Scotti A, Estevez-Loureiro R, Hernandez AP, et al. MitraClip in secondary mitral regurgitation as a bridge to heart transplantation: 1 year outcomes from the International MitraBridge Registry. J Heart Lung Transplant. 2020 Dec;39(12): 1353-1362.

Abstract:

BACKGROUND: Patients awaiting heart transplantation (HTx) often need bridging therapies to reduce worsening and progression of underlying disease. Limited data are available regarding the use of the MitraClip procedure in secondary mitral regurgitation for this clinical condition.

METHODS: We evaluated an international, multicenter (17 centers) registry including 119 patients (median age: 58 years) with moderate-to-severe or severe secondary mitral regurgitation and advanced heart failure (HF) (median left ventricular ejection fraction: 26%) treated with MitraClip as a bridge strategy according to 1 of the following criteria: (1) patients active on HTx list (in list group) (n = 31); (2) patients suitable for HTx but awaiting clinical decision (bridge to decision group) (n = 54); or (3) patients not yet suitable for HTx because of potentially reversible relative contraindications (bridge to candidacy group) (n = 34).

RESULTS: Procedural success was achieved in 87.5% of cases, and 30-day survival was 100%. At 1 year, Kaplan−Meier estimates of freedom from the composite primary end-point (death, urgent HTx or left ventricular assist device implantation, first rehospitalization for HF) was 64%. At the time of last available follow-up (median: 532 days), 15% of patients underwent elective transplant, 15.5% remained or could be included in the HTx waiting list, and 23.5% had no more indication to HTx because of clinical improvement.

CONCLUSIONS: MitraClip procedure as a bridge strategy to HTx in patients with advanced HF with significant mitral regurgitation was safe, and two thirds of patients remained free from adverse events at 1 year. These findings should be considered exploratory and hypothesis-generating to guide further study for percutaneous intervention in high-risk patients with advanced HF. “

Expert Summary by Barbara Wilkey, MD

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References:

  1. Feldman T, Foster E, Glower DD, Kar S, Rinaldi MJ, Fail PS, Smalling RW, Siegel R, Rose GA, Engeron E, Loghin C, Trento A, et al. for the EVEREST II Investigators. Percutaneous Repair or Surgery for Mitral Regurgitation. N Engl J Med 2011;364:1395-1406.
  2. Stone GW, Lindenfeld J, Abraham WT, Kar S, Lim S, Mishell JM, Whisenant B, Grayburn PA, Rinaldi M, Kapadia SR, Rajagopal V, Sarembock IJ et al. for the COAPT Investigators. Transcatheter Mitral-Valve Repair in Patients with Heart Failure. N Engl J Med 2018; 379: 2307-2318.

Prevalence and Patterns of Opioid Use Before and After Liver Transplantation

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Abdominal Organ Transplant Article of the Month

Abstract:

Background. Opioid use in liver transplantation is poorly understood and has potential associated morbidity.

Methods. Using a national data set of employer-based insurance claims, we identified 1257 adults who underwent liver transplantation between December 2009 and February 2015. We categorized patients based on their duration of opioid fills over the year before and after transplant admission as opioid naive/no fills, chronic opioid use (≥120 d supply), and intermittent use (all other use). We calculated risk-adjusted prevalence of peri-transplant opioid fills, assessed changes in opioid use after transplant, and identified correlates of persistent or increased opioid use post-transplant.

Results. Overall, 45% of patients filled ≥1 opioid prescription in the year before transplant (35% intermittent use, 10% chronic). Post-transplant, 61% of patients filled an opioid prescription 0–2 months after discharge, and 21% filled an opioid between 10–12 months after discharge. Among previously opioid-naive patients, 4% developed chronic use post-transplant. Among patients with pre-transplant opioid use, 84% remained intermittent or increased to chronic use, and 73% of chronic users remained chronic users after transplant. Pre-transplant opioid use (risk factor) and hepatobiliary malignancy (protective) were the only factors independently associated with risk of persistent or increased post-transplant opioid use.

Conclusions. Prescription opioid use is common before and after liver transplant, with intermittent and chronic use largely persisting, and a small development of new chronic use post-transplant. To minimize the morbidity of long-term opioid use, it is critical to improve pain management and optimize opioid use before and after liver transplant.

Expert summary by Cara Crouch, MD

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References:

  1. Cron D, Tincopa M, Lee J, Waljee A, Hammoud A, Brummet C, Waljee J, Englesbe M, Sonnenday C. Prevalence and Patterns of Opioid Use Before and After Liver Transplantation. Transplantation. 2021; 105(1):100-107
  2. Braun H, Ascher N. Opioid Use and Liver Transplantation. Transplantation. 2021; 105(1):25-26