Role of cardiovascular intervention as a bridge to liver transplantation

Quantitative blood flow evaluation of vasodilation-stress compared with dobutamine-stress in patients with end-stage liver disease using 82Rb PET/CT

BACKGROUND

Our aim was to determine if end-stage liver disease (ESLD) is associated with an attenuated response to vasodilator-stress or dobutamine-stress using 82Rb-PET MPI with blood flow quantification.

METHODS AND RESULTS

Pre-liver transplant patients who had a normal dipyridamole-stress (n = 27) or dobutamine-stress (n = 26) 82Rb PET/CT MPI study with no identifiable coronary artery calcium were identified retrospectively and compared to a prospectively identified low-risk of liver disease dipyridamole-stress control group (n = 20). The dipyridamole-stress liver disease group had a lower myocardial flow reserve (MFR) (1.89 ± 0.79) than the control group (2.79 ± 0.96, P < .05). The dobutamine-stress group had a higher MFR than both other groups (3.69 ± 1.49, P < .05). A moderate negative correlation between MELD score and MFR was demonstrated for the dipyridamole-stress liver disease group (r = - 0.473, P < .05). This correlation was not observed for the dobutamine-stress liver disease group (r = - 0.253, P = .21). The liver failure group as a whole (n = 53) had a higher resting myocardial blood flow (0.97 ± 0.33 mL/min/g) than the control group (0.82 ± 0.26, P < .05).

CONCLUSION

Dipyridamole demonstrates an attenuated vasodilatory response in ESLD patients compared to a non-ESLD control group related to higher resting blood flow and comparatively reduced stress blood flow. Dobutamine does not demonstrate this effect implying it may be the preferred pharmacologic MPI stress agent for ESLD patients.

Cirrhotic Cardiomyopathy - A Veiled Threat

Cirrhotic cardiomyopathy (CCM) is defined as cardiac dysfunction in patients with liver cirrhosis without pre-existing cardiac disease. According to the definition established by the World Congress of Gasteroenterology in 2005, the diagnosis of CCM includes criteria reflecting systolic dysfunction, impaired diastolic relaxation, and electrophysiological disturbances. Because of minimal or even absent clinical symptoms and/or echocardiographic signs at rest according to the 2005 criteria, CCM diagnosis is often missed or delayed in most clinically-stable cirrhotic patients. However, cardiac dysfunction progresses in time and contributes to the pathogenesis of hepatorenal syndrome and increased morbidity and mortality after liver transplantation, surgery or other invasive procedures in cirrhotic patients. Therefore, a comprehensive cardiovascular assessment using newer techniques for echocardiographic evaluation of systolic and diastolic function, allowing the diagnosis of CCM in the early stage of subclinical cardiovascular dysfunction, should be included in the screening process of liver transplant candidates and patients with cirrhosis in general. The present review aims to summarize the most important pathophysiological aspects of CCM, the usefulness of contemporary cardiovascular imaging techniques and parameters in the diagnosis of CCM, the current therapeutic options, and the importance of early diagnosis of cardiovascular impairment in cirrhotic patients.

Preoperative cardiac assessment in liver transplant candidates

New and extended indications, older age, higher cardiovascular risk, and the long-standing cirrhosis-associated complications mandate specific skills for an appropriate preoperative assessment of the liver transplant (LT) candidate. The incidence of cardiac diseases (dysrhythmias, cardiomyopathies, coronary artery disease, valvular heart disease) are increasing among LT recipients: however, no consensus exists among clinical practice guidelines for cardiovascular screening and risk stratification. In spite of different "transplant center-centered protocols", basic "pillars" are common (electrocardiography, baseline echocardiography, functional assessment). Owing to intrinsic limitations, yields and relevance of noninvasive stress tests, under constant scrutiny even if used, are discussed, focusing the definition of the "high risk" candidate and exploring noninvasive imaging and new forms of stress imaging. The aim is to find an appropriate and rational stepwise algorithm. The final commitment is to select the right candidate for a finite resource, the graft, able to save (and change) lives.

Preoperative QTc Interval is Not Associated With Intraoperative Cardiac Events or Mortality in Liver Transplantation Patients

OBJECTIVES

The primary objective of this study was to determine whether liver transplantation recipients with preoperative prolonged corrected (QTc) intervals have a higher incidence of intraoperative cardiac events and/or postoperative mortality compared with their peers with normal QTc intervals.

DESIGN

This was a retrospective cohort study.

SETTING

Single academic hospital in New York, NY.

PARTICIPANTS

Patients undergoing liver transplantation between 2007 and 2016.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Data relating to all liver transplantation recipients with preoperative electrocardiograms were queried from an institutional anesthesia data warehouse and electronic medical records. Primary outcomes were a composite outcome of intraoperative cardiac events and postoperative mortality. Patients with a prolonged QTc interval (>450 ms for men, >470 ms for women) did not demonstrate an association with intraoperative cardiac events, 30- or 90-day mortality, in-hospital mortality, or overall mortality compared with recipients in the normal QTc interval group. A prolonged QTc was found to be associated with increased anesthesia time, surgical time, length of hospital stay, and incidence of fresh frozen plasma and platelets transfusion.

CONCLUSIONS

Prolonged QTc interval is not associated with an increased incidence of intraoperative cardiac events or mortality in liver transplantation recipients. The demonstrated correlation among QTc length and Model for End-stage Liver Disease score, blood component requirements, surgical and anesthetic times, and hospital length of stay likely represents the association between QTc length and severity of liver disease.

Cardiac diseases among liver transplant candidates

Improvements in early survival after liver transplant (LT) have allowed for the selection of LT candidates with multiple comorbidities. Cardiovascular disease is a major contributor to post-LT complications. We performed a literature search to identify the causes of cardiac disease in the LT population and to describe techniques for diagnosis and perioperative management. As no definite guidelines for preoperative assessment (except for pulmonary heart disease) are currently available, we recommend an algorithm for preoperative cardiac work-up.

Multidisciplinary approach to cardiac and pulmonary vascular disease risk assessment in liver transplantation: An evaluation of the evidence and consensus recommendations

Liver transplant (LT) candidates today are older, have greater medical severity of illness, and have more cardiovascular comorbidities than ever before. In addition, there are specific cardiovascular responses in cirrhosis that can be detrimental to the LT candidate. Cirrhotic cardiomyopathy, a condition characterized by increased cardiac output and a reduced ventricular response to stress, is present in up to 30% of patients with cirrhosis, thus challenging perioperative management. Current noninvasive tests that assess for subclinical coronary and myocardial disease have low sensitivity, and altered hemodynamics during the LT surgery can unmask latent cardiovascular disease either intraoperatively or in the immediate postoperative period. Therefore, this review, assembled by a group of multidisciplinary experts in the field and endorsed by the American Society of Transplantation Liver and Intestine and Thoracic and Critical Care Communities of Practice, provides a critical assessment of the diagnosis of cardiac and pulmonary vascular disease and interventions aimed at managing these conditions in LT candidates. Key points and practice-based recommendations for the diagnosis and management of cardiac and pulmonary vascular disease in this population are provided to offer guidance for clinicians and identify gaps in knowledge for future investigations.

Predictors of Cardiovascular Events After Liver Transplantation

Indications for liver transplant have been extended, and older and sicker patients are undergoing transplantation. Infectious, malignant, and cardiovascular diseases account for the most posttransplant deaths. Cirrhotic patients can develop heart disease through systemic diseases affecting the heart and the liver, cirrhosis-specific heart disease, or common cardiovascular. No single factor can predict posttransplant cardiovascular complications. Patients with history of cardiovascular disease, and specific abnormalities on echocardiography, electrocardiography, or serum markers of heart disease seem to be at increased risk of complications. Pretransplant cardiovascular evaluation is essential to detecting these risk factors so their effects can be mitigated through appropriate intervention.

Cirrhotic cardiomyopathy

During the course of cirrhosis, there is a progressive deterioration of cardiac function manifested by the disappearance of the hyperdynamic circulation due to a failure in heart function with decreased cardiac output. This is due to a deterioration in inotropic and chronotropic function which takes place in parallel with a diastolic dysfunction and cardiac hypertrophy in the absence of other known cardiac disease. Other findings of this specific cardiomyopathy include impaired contractile responsiveness to stress stimuli and electrophysiological abnormalities with prolonged QT interval. The pathogenic mechanisms of cirrhotic cardiomyopathy include impairment of the b-adrenergic receptor signalling, abnormal cardiomyocyte membrane lipid composition and biophysical properties, ion channel defects and overactivity of humoral cardiodepressant factors. Cirrhotic cardiomyopathy may be difficult to determine due to the lack of a specific diagnosis test. However, an echocardiogram allows the detection of the diastolic dysfunction and the E/e′ ratio may be used in the follow-up progression of the illness. Cirrhotic cardiomyopathy plays an important role in the pathogenesis of the impairment of effective arterial blood volume and correlates with the degree of liver failure. A clinical consequence of cardiac dysfunction is an inadequate cardiac response in the setting of vascular stress that may result in renal hypoperfusion leading to renal failure. The prognosis is difficult to establish but the severity of diastolic dysfunction may be a marker of mortality risk. Treatment is non-specific and liver transplantation may normalize the cardiac function.