Cardiac Allograft Vasculopathy, Heart Transplant
Conditions
Brief summary
Cardiac allograft vasculopathy is a common complication affecting heart transplant patients. This condition causes narrowing of the heart arteries leading to graft dysfunction. The research team is investigating whether early antiplatelet therapy post heart transplant can prevent the development of CAV. This study will determine the feasibility of a large multicenter randomized placebo-controlled trial to answer this question.
Detailed description
Heart transplant patients who fulfill selection criteria will undergo baseline clinical evaluation and data collection. Participants will be randomized to either placebo, aspirin or clopidogrel to be taken daily for the duration of the study. Patients will undergo invasive coronary studies (angiography, optical coherence tomography and intracoronary flow) and platelet function testing at 2 and 12 months post heart transplant. In addition, angiography will be performed at 24 months post heart transplant and thereafter according to institutional protocol. The primary analysis will determine the feasibility of conducting a large multicenter randomized placebo controlled trial by assessing recruitment rates, event rates, treatment crossovers and loss to follow-up. Secondary analyses will include assessing the effect of antiplatelet treatment on angiographic CAV, coronary intimal disease on optical coherence tomography, coronary macrovascular and microvascular function by intracoronary flow measures, and platelet function.
Interventions
DRUGPlacebo
patients randomized to placebo study group will be dispensed placebo capsules to be taken daily for the duration of the treatment
DRUGaspirin
patients randomized to aspirin study group will be dispensed aspirin capsules to be taken daily for the duration of the treatment
DRUGClopidogrel
patients randomized to clopidogrel study group will be dispensed clopidogrel capsules to be taken daily for the duration of the treatment
Sponsors
Ottawa Heart Institute Research Corporation
Canadian Institutes of Health Research (CIHR)
Study design
Allocation
RANDOMIZED
Intervention model
PARALLEL
Primary purpose
TREATMENT
Masking
TRIPLE (Subject, Caregiver, Investigator)
Masking description
Patients, clinical care providers and research staff will be blinded to treatment allocation.
Intervention model description
2:2:1 randomization to placebo-control, aspirin 81 mg daily or clopidogrel 75 mg daily
Eligibility
Sex/Gender
ALL
Age
18 Years to No maximum
Healthy volunteers
No
Inclusion criteria
1. Heart transplant 2. Age ≥18 years 3. Able to provide informed consent
Exclusion criteria
1. Allergy or known intolerance to aspirin 2. Allergy or known intolerance to clopidogrel 3. Intracranial hemorrhage ≤14 days 4. Bleeding disorder 5. Platelet count \<50 x 109/L 6. History of aspirin related gastrointestinal bleeding or ulcers 7. Non-cardiac indication for antiplatelet therapy 8. Anticoagulation \>3 months 9. Allergy to iodinated contrast 10. Unable to undergo coronary angiography due to glomerular filtration rate ≤30 mL/min/1.73 m2 for non-dialysis patients 11. Unable to undergo coronary angiography due to unsuitable vascular access 12. Combined solid organ transplantation.
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Feasibility: Recruitment rate | 3 years | Average recruitment rate of 4.5 patients per month at 3 study sites |
| Feasibility: CAV event rate | 3 years | 2-year CAV event rate of \>8% |
| Feasibility: Treatment cross over rate | 3 years | Crossover from aspirin to placebo \<2%, clopidogrel to placebo \<2%, placebo to aspirin \<4%, placebo to clopidogrel \<1% |
| Feasibility: Loss to follow up rate | 3 years | Loss-to-follow-up \<1% |
| Feasibility: Compliance to treatment | 3 years | Compliance to treatment \>80% |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Cardiac allograft vasculopathy | 1 and 2 years post transplant | Angiographic CAV disease severity according to ISHLT CAV 0-3 grading |
| Coronary intimal disease | 2 months, 1 year post transplant | Coronary intimal volume measured on OCT |
| Coronary endothelial function | 2 months and 1 year post transplant | Coronary flow reserve measured by intracoronary flow assessment |
| Coronary macrovascular function | 2 months and 1 year post transplant | Fractional flow reserve measured by intracoronary flow assessment |
| Coronary microvascular function | 2 months and 1 year post transplant | Index of microcirculatory resistance measured by intracoronary flow assessment |
| Platelet Function | Baseline, 2 months and 1 year post transplant | Assessment of response to antiplatelet therapy using Enzyme-Linked Immunosorbent Assays (ELISA) for thromboxane B2 and Vasodilator Stimulated Phosphoprotein (VASP). |
Countries
Canada
Contacts
CONTACTSharon Chih
CONTACTHeather Ross
PRINCIPAL_INVESTIGATORSharon Chih
Ottawa Heart Institute Research Corporation
Outcome results
None listed