Cardiopulmonary Stress Testing (CPET) AlloSure Study

The specific research questioned aimed to be addressed with this proposed study are:

i. Are dd-cfDNA levels in heart transplant recipients independent of recent cardiopulmonary exercise? More specifically, does the metabolic demand of maximal cardiopulmonary exercise in recent heart transplant recipients trigger a release of dd-cfDNA (if so, then what is the time course for resolution back to baseline?) ii. If dd-cfDNA does not release to any significant degree with cardiac allografts with short donor-ischemic time, does this test characteristic continue to hold for cardiac allografts transplanted after longer donor ischemic times? iii. In cardiac transplant recipients with medically stabilized, treated antibody-mediated rejection (AMR) and persistent dd-cfDNA elevation, does a discrete episode of maximal cardiometabolic activity trigger any additional elevation of dd-cfDNA, and again, with what time course?

Inclusion criteria

Post-orthotopic heart transplant patients

Exclusion criteria

• orthopedic, neurologic and/or any other limitations that do not allow for exercise testing on a treadmill or cycle ergometer;
• individuals who require supplemental oxygen or have current permanent tracheostomies will be excluded from this study;
• individuals who are discharged to a long-term acute care facility;
• skilled nursing facility or with palliative care or hospice care will be excluded; (e) inmates and pregnant women;

(f) patients with antibody-mediate rejection that are not felt to be safe for cardiopulmonary stress testing.