Page 20 - Heart Transplant Protocol

Heart Function Service: Heart Transplant Protocols

insult may be in the left ventricle or only in patchy areas and therefore a negative biopsy cannot rule out
rejection. Echocardiography is very helpful and MRI is becoming increasingly useful if the patient is
stable. Biomarkers have been sought but, at least in pediatrics, have not been validated.

Acute Cardiac Cellular Rejection

Acute cellular rejection (ACR) is most common in the first 6 months after heart transplantation,
although it can occur anytime post-transplant and is primarily T cell mediated. Approximately
20 to 40% of Heart transplant recipients will experience as least one episode of ACR in the first
postoperative year. The gold standard for diagnosis is on the endomyocardial biopsy with
defined histopathologic features. The grading system was standardized in 2005 by the ISHLT.
The grading system goes from 0R to 3R.

2005 ISHLT Cellular Rejection Grading Criteria

Adapted from 2004 ISHLT Standardized Cardiac Biopsy Grading: Acute Cellular Rejection

Grade Severity Histologic Findings
1 R Mild Interstitial and/or perivascular
infiltrate with up to 1 focus of
myocyte

2 R Moderate ≥ Foci of infiltrate with
associated myocyte damage

3 R Severe Diffuse infiltrate with
multifocal myocyte damage ±

edema ± hemorrhage ±
vasculitis

Grade 0R

Updated November 9, 2017 20