Long-term cardiovascular risk in the orthotopic liver transplant population

Abstract

Orthotopic liver transplantation (OLTx) is a life saving option for selected patients with end stage liver disease (ESLD). The success of OLTx, through improved surgical techniques and posttransplant care, has contributed to a donor organ deficit for an expanding pool of potential recipients. 1 This donor shortage places an increased emphasis on identifying OLTx candidates with the best chance of long-term survival.Patients with symptomatic coronary artery disease who undergo OLTx have a poor prognosis; 2 that is why most centers now exclude such patients from transplant consideration. Even in asymptomatic ESLD patients cardiovascular (CV) events are a major source of morbidity and mortality in OLTx recipients. 1,3 In the operative and peri-operative period, these events include life-threatening arrhythmias at the time of donor liver reperfusion, myocardial ischemia or myocardial infarction (MI) or congestive heart failure. In long term OLTx survivors, CV events include unstable angina, MI or death. Therefore, assessing short and long term CV risk is an important aspect of the ESLD pretransplant evaluation.Currently, there is no widely accepted algorithm to identify patients that are at high risk of perioperative transplant CV events from the hemodynamic stress of surgery. Contrary to data in the vascular surgery population 4,5 the utility of non-invasive cardiac stress tests in pre-OLTx candidates is controversial. 5-11 Retrospective reviews using nuclear SPECT scanning in ESLD patients have reported everything from the test not being useful in risk stratification for post-transplant CV events, 6 to a 99% negative predictive value for excluding CV events for up to 2 years post OLTx (8). In a study of 78 OLTx pts who had coronary angiography as the gold standard, pre-op pharmacologic nuclear perfusion imaging showed a positive predictive power of the nuclear study was only 22% with a negative predictive power of 77%. 7 In many institutions, dobutamine stress echocardiography (DSE) is performed for pre-OLTx risk stratification instead of nuclear perfusion imaging. 9 -11 A benefit of DSE is the ability of echocardiography to simultaneously assess pulmonary hypertension, intrapulmonary shunting and valvular heart disease. 9 In 71 patients a negative DSE had a 100% negative predictive value for excluding post-operative cardiac events, but the predictive value of a positive test was poor. 9 In 40 patients that had a negative DSE and OLTx no events were observed, also suggesting a powerful negative predictive value. 10 In contrast, in a third study assessing pre-operative DSE eight of 61 OLTx patients had a CV event, all in patients with a negative or nondiagnostic study. Of note, a non-diagnostic study due to failure to reach their target (85% maximal) heart rate was seen in 53% of these patients. 11 Whereas the reasons for the differences in the predictive value for CV events for both preoperative nuclear and DSE is unknown, it may be related to the hemodynamic derangements commonly found in ESLD patients. Character...

Adult liver transplantation in the USA

“…The use of nuclear functional cardiovascular assessment with nuclear singlephoton emission computed tomography (SPECT) in the liver transplant evaluation is not recommended because of poor sensitivity and specificity (37 and 63%, respectively) and poor correlation with preoperative cardiac outcomes [36][37][38].…”

Coronary artery disease in orthotopic liver transplantation: Pretransplant assessment and management

“…In terms of cardiovascular risk factors, retrospective analyses in OLT cohorts for early (<6 months) and late (≤10 years) postoperative complications have failed to identify a consistent set of risk predictors 32, 33. However, because these studies were of limited size, their findings may have statistical limitations and should be treated with caution 34. Moreover, it has been suggested that the risk‐factor profile for CAD in these patients may differ from those in which the commonly used scores were validated and that actual risk may be underestimated 14.…”

“…Functional cardiovascular assessment with nuclear single photon emission computed tomography (SPECT) has been validated extensively in preoperative patients. However, the evidence for its use in patients with ESLD is poor both in terms of diagnostic performance in comparison with angiography (a sensitivity of 37% and a specificity of 63%35) and in terms of its ability to predict perioperative outcomes 34, 36. This has been postulated to be due to the decreased arterial resistance associated with ESLD, which renders the vasodilator provocation with adenosine or dipyridamole insufficient to produce the necessary increases in coronary blood flow.…”

Preoperative dobutamine stress echocardiographic findings and subsequent short-term adverse cardiac events after orthotopic liver transplantation

“…Traditional risk stratification using established algorithms such as the Framingham risk score (FRS) underestimate CV event rate risk and are poor predictors of risk in this population 2. Other risk stratification methods such as the Systematic Coronary Risk Evaluation Project and the Prospective Cardiovascular Münster Study have also been studied3 but have no better sensitivity and specificity than the FRS 4…”