Geraldine Diaz reports on congress highlights
June 5, 2014
-Vanguard Grand Rounds
Dr. Geraldine Diaz who presented two cases of intra-cardiac
thromboses: one which resulted in a transient, minimally symptomatic
embolus, and a second that resulted in an intra-operative
mortality. Dr. Andre DeWolf discussed the significance of intracardiac thrombus formation during liver transplantation that has an
estimated incidence of 1-4% but a 50% mortality rate. Etiology,
proposed risk factors, diagnosis, prevention, and potential treatment
modalities were presented. A central theme was the coagulopathy of
liver failure is a constantly changing mileau impacted by the
comorbidities of liver disease. ICT occurs due to the imbalance
between the procoagulation and anticoagulation systems that occur
during conditions that stimulate inflammation, such as liver
transplantation. Essential to diagnosing ICT is monitoring that should
include trans-esophageal echocardiography and pulmonary arterial
catheter. Likely risk factors include continuous veno-venous
hemodialysis and rapid administration of calcium, platelets,
cryoprecipitate, and other procoagulants. Rapid diagnosis with TEE
and PAC should prompt immediate treatment with low dose tPA (0.54.0mg) and thrombectomy if clinically indicated.
Featured Symposium: Risk Evaluation and Outcomes
William Bernal from Kings College opened the session with the topic
‘Should we set limits on an acceptable BMI for transplantation?’ He
discussed the limitations of BMI in the setting of liver disease and its
relationship to surgical outcomes. BMI has been shown to be a
marker for the presence of comorbidities, not a sole determinant of
outcome. Both ends of the spectrum, severe underweight and
overweight, have been demonstrated to increase mortality among
patients receiving transplantation with stronger data for
sarcopenia. Both groups, 18.5 40, exhibir increased length of stay,
rate of re-transplantation, and mortality. To date, there are no data to
support an absolute BMI cutoff for liver transplantation. BMI is not an
independent predictor of outcome and should be utilized with clinical
judgment in determining risk.
What is the best measure for nutritional reserve? The role for
anthropometric assessment was explored. Hand-grip strength is a
measure of muscle strength with decreased hand grip strength
associated with decreased survival. Analytic morphomics provide
additional data. In summary, the decision to proceed still requires
interpolation of many nonspecific data points.
Chris Snowden from Freeman Hospital complemented the above
lecture by discussing ‘Is the measurement of physiologic reserve the
best predictor of outcomes? He began by defining the term ‘frailty’ as
decreased physiologic reserve (muscular and cardiorespiratory)
across multiple systems that increases patient vulnerability to
stressors. Sarcopenia is a component of frailty that is frequently
associated with chronic liver disease. Sarcopenia is an independent
predictor of pre- and post-transplant morbidity and mortality. The
resolution of sarcopenia following liver transplantation remains
variable. Similar to sarcopenia, cardiorespiratory reserve (CRR) is
independent of MELD and unrelated to the degree of liver disease.
Poor CRR has been shown to decrease waitlist survival. The effect
of targeted interventions such as exercise and lifestyle modification to
improve CRR, termed pre-habilitation, on waitlist mortality and posttransplant outcomes are just being recognized.
Susan Mandell from the University of Colorado discussed measures
of predicting short and long-term outcomes. She began by
introducing the concept of risk-adjusted outcomes, which reflect the
context of the observation and reduces the effect of heterogeneity on
outcomes. Risk adjusted outcome is essential to understand
outcome studies and allows a center to compare its performance
between different centers. Two important measures of outcomes are:
1) opportunity to treat (evidence-based practice) and 2) aggregate
scores (practice-based evidence). Evidence based practice is derived
from randomized controlled trials where conditions are controlled and
results may be limited to a small segment of the population. Practice
based evidence is a different form of evidence and can be
generalized to a wider population. This form of outcome measure
relies on uncontrolled analysis of patient outcomes, where clinical
practice is measured and documented. An example of practice-based
evidence is the NSQIP (National Surgical Quality Improvement
Program). The ASTS is currently developing TransQIP (Transplant
Quality Improvement Program), which is practice-based and will
provide a novel outcomes analysis approach for solid organ
transplantation. Dr. Mandell recommended the utilization of both
evidence-based and practice-based measures as it applies to our
clinical practice. Finally, she emphasized that most outcomes are
shared across all disciplines and anesthesiologists have an equal role
in outcomes reporting.
Gareth Ackland from University College London finished the session
by discussing the impact of early post-operative morbidity on longterm patient outcomes. Postoperative complications within 30 days,
even as early as postoperative day #2, have a dramatic effect on
long-term morbidity and mortality. An example is the impact of
infection and inflammation on tumor progression by impairing
perioperative innate immunity. He emphasized the NSQIP database
as a valuable resource to improve outcomes.
Concurrent Oral Abstract Session: Anesthesia/Critical
Care
Dr. Joshua Herborn from Northwestern University presented a patient
with HCV cirrhosis and preoperative TTE demonstrating moderate
tricuspid regurgitation, dilated right ventricle with normal RV systolic
function. In the OR, difficulty with placement of PAC with
indistinguishable RA, RV, and PAP waveforms occurred. TEE
revealed severe tricuspid regurgitation and enlarged RV. The
transplant was aborted and the pt received diuretics in the ICU.
Despite diuretics, TTE demonstrated moderate to severe TR and a
tethered TV indicating chronic RV overload. The patient was then
delisted from receiving a liver transplant. This case highlights the
importance of preoperative cardiac evaluation and the significance of
severe tricuspid regurgitation on patient and graft survival.
Dr. Alejandro Mejia from Dallas, TX discussed a patient with HCV
cirrhosis and HCC presenting for liver transplantation. The pt had an
unremarkable TTE except for a positive bubble study 6 months prior.
In the OR, during the hepatectomy, the patient had a sudden, acute
elevation of RVSP >80 mmHg and right ventricular dysfunction noted
on TEE. Hemodynamic instability occurred and was refractory to
vasoactive therapy. Epoprosterenol infusion and inhaled nitric oxide
improved hemodynamics and RV function, allowing the liver
transplantation to proceed. The patient was extubated and required
epoprosterenol for up to 4 months after transplant. The authors
concluded that this is a case of portopulmonary hypertension
occurring during liver transplantation.
Dr. Amanda Trommello from Thomas Jefferson University reported a
successful outcome following early extubation in a patient with
hepatopulmonary syndrome who underwent liver transplantation. The
patient was extubated eight hours after transplantation despite
marginal oxygenation on high FiO2, and was discharged from the
ICU after 48 hours with minimal oxygen requirements. The authors
concluded that minimizing positive pressure ventilation by early
extubation is beneficial in patients with hepatopulmonary syndrome.
June 6, 2014
Vanguard Debates
Kym Watt and Michael Charlton debated “Should BMI limit transplant
candidacy.” Each reviewed the literature and arrived at the same
conclusion which is: BMI, in an of itself, should not be a restriction to
transplant. Multiple studies support extension of liver transplantation
to highly selected obese patients regardless of BMI. However, BMI is
a harbinger of other physiologic conditions such as cardiac disease,
diabetes, pulmonary function, and the metabolic syndrome which can
result exclusion.
Oral Abstract Session: Anesthesia/Critical Care
Medicine
Does the Severity of Portopulmonary Hypertension (POPH) Matter in
the ICU Post-liver Transplant? (O-79) Gallo de Moraes etal from
Mayo Clinic conducted a study to evaluate the effect of POPH
severity on short-term postoperative outcomes. Fourteen patients
with POPH who underwent liver transplantation were included in the
study: 6 patients had severe POPH (MPAP >45mmHg) while 8
patients had not-severe POPH (MPAP < 45mmHg). ICU length of
stay, days on mechanical ventilation, and vasopressor requirements
were not significantly different between the groups.
Target Dobutamine Stress Test (tDSE) in Predicting Adverse Cardiac
Events (PACE) Within One Year Following Liver Transplantation. (O80) Gitman et al from Ochsner Medical Center performed a
retrospective study to evaluate the accuracy of tDSE in PACE one
year following liver transplantation. The authors demonstrated that
tDSE had a low sensitivity and low positive predictive value, but with
specificity of >95%. As with previous cardiac assessments,
successful screening for cardiac disease among OLT candidates is
best achieved through multimodality approaches.
Impact of Early Pre-Transplant Sepsis on Post Liver Transplant
Outcome in Cirrhotic Patients, (O-81) Khoy-Ear from Beaujon
Hospital conducted a retrospective observational single-center study
to determine the effect of pre-transplant sepsis (PTS) on posttransplant outcomes. Among their cohort, 21% had PTS which
included spontaneous bacterial peritonitis, urinary tract infections,
and pneumonia. 22% were in septic shock, 24% required mechanical
ventilation, and 22% required renal replacement therapy. The authors
demonstrated that PTS resulted in increased post-transplant
infections, vasopressor requirements, renal replacement therapy,
days on mechanical ventilation, and hospital length of stay. The
authors advocated for further study in identifying specific predictors to
aid in the decision to offer transplantation in the presence of PTS.
Comparison of Three Surgical Techniques in Liver Transplantation:
Caval Cross Clamp(CCC), Piggyback (PB), and Piggyback Plus
Cavoportal Shunt (PB+CPS) (O-82) Malara etal from the Royal Free
Hospital performed a retrospective review to compare three surgical
techniques and their effect on perioperative hemodynamic
stability, acid-base balance, and renal function. The choice of
surgical technique was not randomized but determined by the
surgeon during the transplant procedure. Their data suggested PB
and PB+CPS resulted in a more favorable hemodynamic and
metabolic profile, with potentially improved renal function. However,
their conclusions were limited by the selection bias in surgical
technique.
Blasi et al from the University of Barcelona summarized pioneering
work their group has done on transplantation of uncontrolled donation
after circulatory determination of death (uDCD) in Liver Transplant
from Uncontrolled DCD Donors: A Challenge in Coagulation
Management. (O-87) In this study, the group’s experience with 39
uDCD donors was compared to a matched cohort of donation after
neurologic death allograft recipients. uDCD allograft recipients
demonstrated lower mean arterial pressure and systemic vascular
resistance upon reperfusion with a greater need for vasoactive
support. Early allograft dysfunction was significantly greater in the
uDCD group resulting in greater blood loss, higher transfusion
requirements, an increased incidence for renal replacement therapy,
a higher incidence of consumptive coagulopathy, and longer
hospitalization. Long-term survival data of uDCD recipients were not
presented. The authors concluded that while progress is occurring in
the application of uDCD, peri-operative management of these
patients remains complex.
Effect of Vasoactive Agents on Blood Loss and Transfusion
Requirements During Orthotopic Liver Transplantation (O-84). Vitin et
al from the University of Washington explored the effect of
intraoperative low dose vasopressin infusion +/- additional
vasopressors compared to a group receiving vasoactive agents alone
without vasopressin infusion during liver transplantation. There were
no statistically significant differences noted on hemodynamic stability,
transfusion requirements, and postoperative outcomes among the
two groups. However, the authors observed decreased blood loss
during the pre-reperfusion stage among the patients that received
low-dose vasopressin infusion. Further study is advocated by the
authors.
Applicability of Rapid Thromboelastography and Functional
Fibrinogen Assay in Adult Liver Transplantation (O-85). Dr. Sakai
from the University of Pittsburgh conducted a prospective
observational study to compare the conventional kaolin
thromboelastography (k-TEG) to the new TEG variants, rapid TEG (rTEG) and functional fibrinogen TEG (ff-TEG), on their applicability in
liver transplantation. r-TEG decreased test time but was associated
with a higher incidence of measurement error compared to k-TEG. ffTEG had a strong correlation with plasma fibrinogen level after
induction of anesthesia, but this correlation was weaker during postreperfusion. The effect of variation among the various modalities on
clinical decision-making was unclear. Prospective studies involving
larger cohorts are necessary to enhance their observations.
Epidural Anesthesia is Safe and Effective for Donor Hepatectomies –
Our Experience with 169 cases (O-86). Rajakumar et al from Global
Health City reported their experience with epidural anesthesia for
postoperative pain control in living donors. The authors conducted a
retrospective analysis of 157 donors who received epidural
anesthesia. Compared to patients who received fentanyl IV infusion,
patients who were managed with epidural anesthesia demonstrated
significantly lower pain scores. Epidural catheters were removed on
postoperative days 3 and 4 without neurologic sequelae. The authors
concluded that appropriate timing of epidural placement and removal
with respect to coagulation status may prevent complications.