November 09, 2014
BOSTON — A review of data on nearly 33,000 liver transplant recipients suggests that some modifiable pretransplant risk factors can account for major adverse cardiovascular events in the first 3 months after surgery.
"What was most interesting to us was that the thromboembolic diseases, which we tend to screen for very closely — pulmonary embolism, myocardial infarction — only accounted for about 7% to 10% of all cases of cardiovascular complications," Lisa VanWagner, MD, a gastroenterology and hepatology fellow at the Northwestern University Feinberg School of Medicine in Chicago.
Before transplantation, "we rigorously evaluate our candidates cardiovascularly, but we focus on coronary disease in our risk stratification, so patients get stress echocardiograms and coronary catheterization. What we tend to forget about are these subclinical changes, that idea of cirrhotic cardiomyopathy, the arrhythmic potential, and the chronotropic incompetence that happens in cirrhosis of the heart, which is the inability to mount a response to stress," she told Medscape Medical News.
Cardiovascular events — including myocardial infarction, heart failure, pulmonary embolism, atrial fibrillation, cardiac arrest, and stroke — are among the leading causes of complications after transplantation, and are associated with worse overall survival in the first year after transplantation.
Dr VanWagner and colleagues created a database to assess the prevalence and predictors of major adverse cardiovascular events in the first few months after transplantation.
They did so by identifying adults who underwent a primary liver transplant from February 2002 to December 2012 in a member institution of the University Health System Consortium, and matching them to recipients in the Organ Procurement and Transplantation Network registry. They used billing codes to assess comorbidities and the incidence of 30- and 90-day major cardiovascular events.
Of the 32,810 patients they identified, 4400 were admitted to a hospital within 30 days of transplantation, and 6095 were admitted within 90 days. Of the patients admitted in the first month, 330 (7.4%) had a major adverse cardiovascular event; of those admitted in the first 3 months, 429 (7.0%) had a major adverse cardiovascular event.
The most common causes of 30- and 90-day adverse events were atrial fibrillation, heart failure, and pulmonary embolism.
Patients who experienced a major adverse cardiovascular event were significantly more likely than other recipients to have alcoholic liver disease or nonalcoholic steatohepatitis as the primary indication for transplantation (P = .0003). They were also more likely to have a higher mean calculated Model for End-Stage Liver Disease score (P = .001), and to have a cardiovascular comorbidity present at the time of transplantation. Significant cardiovascular comorbidities were heart failure (P < .0001), ischemic heart disease (P < .0001), hypertension (P = .05), stroke (P = .001), and atrial fibrillation (P < .0001).
Other significant comorbidities were chronic kidney disease, hepatopulmonary syndrome, and asthma or chronic obstructive pulmonary disease.
On multivariate regression analysis, factors that independently predicted any major adverse cardiovascular event within 90 days included age older than 45 years (incidence rate ratio [IRR], 1.8; 95% confidence interval [CI], 1.2 - 2.7), alcoholic cirrhosis (IRR, 1.6; 95% CI, 1.2 - 2.2), nonalcoholic steatohepatitis (IRR, 1.6; 95% CI, 1.2 - 2.2), a high pretransplant level of creatinine (IRR, 1.1; 95% CI, 1.04 - 1.2), atrial fibrillation (IRR, 6.9; 95% CI, 4.9 - 9.6), and stroke (IRR, 6.3; 95% CI, 1.6 - 25.4).
Major adverse cardiovascular events were also associated with significantly worse 1-year survival (75.2% vs 85.6%; P < .0001).
These findings suggest an opportunity to improve care for liver transplant candidates and enhance recipient selection, said Dr VanWagner.
Certainly alcohol damages the liver, but it also damages the heart.
A gastroenterologist who was not involved in the study told Medscape Medical News that cardiovascular complications are a major problem and have a serious effect on outcomes in patients undergoing liver transplantation.
The investigators "have done a wonderful job looking at risk predictors of complications and describing the major problems that are occurring in the early days after transplantation," said Simon Robson, MD, chief of the division of gastroenterology at Beth Israel Deaconess Medical Center and professor of medicine at Harvard Medical School, both in Boston.
Dr Robson said that the associations the investigators found between postoperative cardiovascular risk and fatty liver disease and alcoholic cirrhosis are particularly important.
"With hepatitis C being eradicated, most of the patients we're going to be transplanting in the next two decades fall into these categories, and in Europe, most of the patients are alcoholic right now. Certainly alcohol damages the liver, but it also damages the heart," he said.
The study was supported by the National Heart, Lung, and Blood Institute; the American Liver Foundation; and the AASLD Foundation. Dr VanWagner and Dr Robson have disclosed no relevant financial relationships.
The Liver Meeting 2014: American Association for the Study of Liver Diseases (AASLD). Abstract 549. Presented November 8, 2014.