The U.S. health care system spends more than $26 billion annually for patients with heart failure (HF). Of the 6 million patients with HF, a quarter million have advanced stages of the disease associated with frequent hospital admissions, low quality of life, and high mortality. Between 2011 and 2017, the total number of annual deaths due to heart failure increased 38% from 58,309 to 80,480. Of these 2017 deaths, 73,682 were among patients greater than 65 years of age, older than the typical eligibility criteria for heart transplant. This population is in desperate need for left ventricular assist device (LVAD) support, as well as the 4,200 patients less than 65 yr. for whom inadequate transplantable hearts were available. For these individuals, LVAD as destination therapy (DTLVAD) is the best opportunity for survival with an acceptable quality of life. Tens of thousands of patients with severe HF deserve a DTLVAD to enable a productive quality life, which can only be achieved by reducing the adverse events that excessively drive the healthcare costs.
LVAD complications commonly include infections, pump malfunction, arrhythmias, heart failure, bleeding, and thrombotic events. However, ischemic and hemorrhagic neurologic events have the greatest adverse impact on quality of life and neurologic events are the leading cause of death for patients on long-term LVAD support. Indeed one third of readmissions are caused by gastrointestinal bleeding (GIB), which affects 30% of LVAD patients and 40% of those with prior GIB event. Poor global outcomes, defined as a composite of death, poor quality of life, recurrent heart failure hospitalizations, or thromboembolic complications such as stroke, occurred most among patients with GIB during the first year post-LVAD implantation.
The etiology of LVAD-related GIB is multifactorial and strongly related to the therapeutic anti-coagulation strategy, a shear-induced acquired von Willebrand syndrome, as well as arterio-venous and angiodysplastic malformations in the gastrointestinal tract. Anti-coagulation increases the risk of GIB. However, the
international normalized ratio value (INR) can vary from therapeutic to subtherapeutic at the time of bleeding. A wide variety of anti-coagulation/antiplatelet strategies have been studied without a robust general set of guidelines emerging. This body of data points to the need to individualize anti-coagulation strategy and intensity, if the high rate of GIB and neurovascular events are to be adequately decreased. But, to date no specific biometric is available that informs anti-coagulation and intracardiac thromboembolic risk minimization.
The clinical development of FibroScint , a 99mTc nuclear probe, will help address this unmet need. FibroScint can be used to rule-out intrapump or intracardiac sources of thromboembolism and as well as provide an imaging biomarker to directly tailor anti-coagulation to minimize thromboembolic risk and GIB hospitalization. These assessments may be considered in the peri-implant period, during hospitalizations for GIB requiring anti-coagulation cessation and restart, as a periodic patient management strategy to ensure negligible stroke risk from intracardiac or intraLVAD thrombus, or as a periodic anti-coagulation adjustment program to minimize bleeding risk as DT LVAD duration progresses.
SPECT image of an LVAD. Bright white spot indicates formation of thrombus within the LVAD.