The prevalence of acute myocardial infarction (AMI) in the heart transplant (HT) population is “very low,” according to research published in the current online edition of the American Journal of Cardiology, but HT patients who do suffer a heart attack are more likely to experience longer hospital stays, higher 30-day readmission rates and greater in-hospital morbidities.
Post-HT survival rates have climbed in recent years, lead author Tariq Enezate, MD, and co-authors said in the journal, eventually reaching a 73-percent five-year survival rate. But, barring one old case that estimated 25 percent four-year prevalence of AMI in HT patients, there’s a paucity of research surrounding the subject.
“The cause of AMI in post-HT depends on the time of presentation,” Enezate, a cardiology fellow at University of Missouri Health Care in Kansas City, Missouri, and colleagues wrote. “Late AMI post-HT is more often related to cardiac allograft vasculopathy (CAV). On the other hand, early AMI is rare and related to either the surgery or graft atherosclerosis.”
“Early” AMI is considered myocardial infarction that strikes less than eight weeks after a person’s heart transplant surgery.
Enezate and his team extracted a study population from the National Readmissions Data 2014 dataset, identifying 259,794 hospital discharges with a principal diagnosis of AMI. The researchers studied all-cause mortality, length of hospital stay, cardiogenic shock, kidney injury, readmission rates and the likelihood of receiving invasive care among the patients, 789 of whom had a history of HT.
According to the study’s results, 1.7 percent of HT patients experience AMI. Compared to non-HT patients, those with heart transplants saw longer lengths of stay, more cardiogenic shock, more acute kidney injury, less catheterization, less use of percutaneous coronary intervention and higher 30-day readmission rates. The authors found no statistically significant differences in all-cause mortality between the groups.
“Compared to a general AMI population, post-HT patients with AMI were associated with higher baseline comorbidities, worse post-AMI in-hospital outcomes and less use of invasive therapy,” Enezate et al. said, noting further research is needed to confirm the study’s results and explore whether factors like early treatment or immunosuppressive therapy would change them.
“We believe [this study] has several important clinical implications,” the authors wrote. “AMI is a potential complication in HT patients. High index of suspicion is needed to prevent any delay in the diagnosis and appropriate treatment, even with the absence of typical symptoms, by a team with expertise in HT. While the pathogenesis of CAV is largely immunogenic, it is unclear whether these immunosuppressants decrease the incidence of AMI.”
After graduating from Indiana University-Bloomington with a bachelor’s in journalism, Anicka joined TriMed’s Chicago team in 2017 covering cardiology. Close to her heart is long-form journalism, Pilot G-2 pens, dark chocolate and her dog Harper Lee.