CLINICAL HEART TRANSPLANTATION
Cardiac Transplant Patients
Response to the
31
P MRS Stress Test
William T. Evanochko, PhD,
a
Steven D. Buchthal, PhD,
a
Jan A. den Hollander, PhD,
a
Charles R. Katholi, PhD,
b
Robert C. Bourge, MD,
a
Raymond L. Benza, MD,
a
James K. Kirklin, MD,
c
and Gerald M. Pohost, MD
a
Background: Previous studies showed low resting phosphocreatine/adenosine
triphosphate (PCr/ATP) ratios within this patient population compared with controls;
however, these low PCr/ATP did not correlate with endomyocardial biopsy rejection.
One possible explanation is the presence of cardiac allograft vasculopathy (CAV),
which might be manifested as a transient ischemic event in the mildly stressed
transplanted heart. If transient ischemia is invoked through the
31
P magnetic resonance
spectroscopy (MRS) stress test, monitoring of such an event should be achievable and
thus implicating possible ischemic involvement.
Methods: Heart transplant patients (n = 25) and normal controls (n = 11) were
studied using the
31
P MRS stress test; 10 patients tested positive ( 2 standard
deviations [SDs] from control values). Patients also were monitored for heart rate and
blood pressure with the handgrip exercise generating a small increase in the rate-
pressure product.
Results: The percent change (%) in the PCr/ATP ratio in the control group was
1.50% 10.6; the transplant population showed an overall change of -6.7% 18.5.
The responders, those that were at or below the 2 SD line from control, had a -25.6
3.6% PCr/ATP; whereas the non-responders reflect a 5.1 13.4%. The responders’
response is quite striking when considering the threshold for an abnormal PCr/ATP %
in response to stress testing was -19.7%, which was the 2 SD mark below the mean
value for the reference population.
Discussion: The
31
P MRS stress test showed that a possible transient ischemic event
occurred in a subset of patients, thus implicating possible CAV in the cardiac transplant
patient. Such an approach may provide an early diagnosis of this disease. J Heart Lung
Transplant 2002;21:522–529.
From the
a
Center for NMR Research and Development and the
Department of Medicine, Division of Cardiovascular Disease,
the
b
Department of Biostatistics, and the
c
Department of
Surgery, Division of Cardiovascular and Thoracic Surgery,
University of Alabama at Birmingham, Birmingham, Alabama.
Submitted July 30, 2001; revised August 28, 2001; accepted
September 4, 2001.
Supported in part by NIH Grant RO1-HL48526 (WTE).
Reprint requests: William T. Evanochko, PhD, Center for NMR
Research and Development and Division of Cardiovascular
Disease, Department of Medicine, University of Alabama at
Birmingham, Birmingham, AL 35294. Telephone: 205-934-
9450. Fax: 205-934-7367. E-mail: wevanochko@cardio.dom.
uab.edu
Copyright © 2002 by the International Society for Heart and
Lung Transplantation.
1053-2498/02/$–see front matter PII S1053-2498(01)00412-0
522