Cardiac allograft remodeling causes poor quality of life, allograft failure and increased mortality after heart transplantation. Risk factors for cardiac allograft remodeling and its progression are poorly defined and there is a need for effective interventions.This is a multi-factorial phenomenon, associated with various immunological and non-immunological factors. Animal studies suggest M-TOR inhibition attenuates cardiac allograft remodeling secondary to down-regulation of M-TOR downstream targets and increased autophagy. There is a paucity of data regarding effect of Sirolimus, a M-TOR inhibitor, on human heart remodeling. This aim of the proposal to identify the prevalence of cardiac allograft remodeling on current immunosuppressive strategies and determine risk factors for its development. It will also identify molecular pathways associated with cardiac allograft remodeling and determine the impact of Sirolimus on these pathways.
Heart transplantation has become a well-established treatment option for patients with end-stage heart disease and currently has a one-year survival rate of 90%, a five-year survival rate of 70%, and 10-year survival rate of 50%. The introduction of anti-rejection treatment thirty years ago with drugs known as calcineurin inhibitors have resulted in a significant improvement in the survival of heart transplant recipients. However, most of this improvement occurs during the first year after transplantation. Beyond the first year, the mortality rate of heart transplant recipients has not changed, which indicates that the causes of late complications have not been affected in the last three decades by improvements in post-transplant care. It becomes apparent that in order to improve the late outcomes, the focus in heart transplant research needs to be shifted to the prevention and the treatment of late complications. Cardiac allograft remodeling (CAR), or changes in heart's geometric pattern, is one of the common complications after heart transplantation and often inflicts poor quality of life, heart failure, and decreased survival. The risk factors and mechanism for the development and progression of CAR are poorly defined, and there is no effective treatment for this condition. In the proposed study, we will identify the prevalence, risk factors, and effect of CAR on physical capacity, cardiac vascular disease, and patient survival after a heart transplant. For assessment of heart geometry, we will use cardiac magnetic resonance imaging (CMRI), a techniques used to visualize the internal structures of the body in detail. CMRI is considered as being a "gold standard" for evaluating the heart's structure and function. We will also evaluate the molecular and genetic markers associated with development and progression of CAR after heart transplantation. The drug Sirolimus, a new anti-rejection agent, can be used in place of calcineurin inhibitors after heart transplantation. Recent experimental and animal studies indicate that Sirolimus can attenuate the changes in the heart's geometry after a transplant (i.e., CAR) and improve heart function. We will assess the effect of Sirolimus on CAR in humans and will evaluate molecular and genetic markers associated with this effect. It is our goal to provide an important insight into the nature of CAR after heart transplantation and its response to new anti-rejection drug Sirolimus. This information will have a significant impact on the treatment of heart transplant recipients and thus improve quality of life and prolong survival after heart transplantation.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
TREATMENT
Masking
NONE
Enrollment
42
1 month post HTx, year 1 and year 2 annual post HTx eval. CMRIs completed using 1.5-Tesla Whole Body MRI system. Scout images will determine short \& long-axis views of the heart. ECG-gated cine MR of 3 long axis and a contiguous short axis orientation will be obtained. T1-weighted delayed enhancement images will be obtained 10 minutes after injection of a gadolinium-based contrast agent. Measurements from each slice will be summed using the method of disks. Myocardial mass will be estimated by multiplying the myocardial wall volume at end diastole by the specific gravity of muscle (1.05gm/ml) and LV hypertrophy will be defined as LV mass indexed to height in meters 2.7 \>/=35.8 g/m 2.7) (18). Delayed Gadolinium enhancement will be defined as any enhancement pattern greater than 0%.
Coronary angiography is a test that uses dye and special x rays to show the insides of your coronary arteries. The coronary arteries supply oxygen-rich blood to your heart. Intravascular ultrasound is a test that uses sound waves to see inside blood vessels. This article discusses intravascular ultrasound to see inside the coronary arteries, the blood vessels that supply the heart.
A surgical procedure in which a diseased heart is replaced with a healthy heart from a deceased person.
Sirolimus (INN/USAN), also known as rapamycin, is an immunosuppressant drug used to prevent rejection in organ transplantation; it is especially useful in kidney transplants. It prevents activation of T cells and B-cells by inhibiting their response to interleukin-2 (IL-2). Sirolimus dosage based on blood levels.
A long, thin tube called a biopsy catheter is inserted through a vein in your neck or grion and guided through your blood vessels to your heart.
To identify the molecular and genetic mechanisms associated with development of early post-transplant CAR, and to evaluate the impact of mTOR-inhibitor Sirolimus on this process.
The Cardiopulmonary Exercise Test is a highly sensitive, non-invasive stress test. It is considered a stress test because the exercise stresses your body's systems by making them work faster and harder. A disease or condition that affects the heart, lungs or muscles will limit how much faster and harder these systems can work. A CPET assesses how well the heart, lungs, and muscles are working individually, and how these systems are working in unison. Your heart and lungs work together to deliver oxygen to your muscles, where it is used to make energy, and to remove carbon dioxide from your body.
University of Nebraska Medical Center
Omaha, Nebraska, United States
Assessment in left ventricular hypertrophy
The primary end point will be the change from baseline in LV mass indexed to height in meters 2.7 and LV concentricity as assessed by MRI during 12 months of the treatment.
Time frame: One year
Assess outcomes
The secondary end points will be changes from baseline in LV function.
Time frame: One year
Access outcomes
Exercise performance (peak VO2, equivalent for carbon dioxide (VE/VCO2)and coronary vessel intimal thickening.
Time frame: One year
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