Bio-energetic response of the heart to dopamine following brain death-related reduced myocardial workload: a phosphorus-31 magnetic resonance spectroscopy study in the cat.

Abstract

OBJECTIVE:

Long-term exposure of the donor heart to high dosages of dopamine in the treatment of brain death-related hemodynamic deterioration has been shown to reduce myocardial phosphocreatine (PCr) and adenosine triphosphate (ATP) in myocardial biopsy specimens and may preclude heart donation for transplantation. Short-term exposure to the acute catecholamine release during the onset of brain death has shown an unchanged PCr/ATP ratio using in vivo phosphorus-31 magnetic resonance spectroscopy (31P MRS). In this study 31P MRS was used to evaluate in vivo myocardial energy metabolism during long-term dopamine treatment.

METHODS:

Twelve cats were studied in a 4.7 Tesla magnet for 360 minutes. At t = 0 minutes, brain death was induced (n = 6). At 210 minutes, when myocardial workload in the brain-death group was reduced significantly, dopamine was infused (n = 12) at 5 microg/kg/min and its dose was consecutively doubled every 30 minutes and was withheld during the last 30 minutes of the experiment. Phosphorus-31 magnetic resonance spectra were obtained from the left ventricular wall during 5-minute time frames, and PCr/ATP ratios were calculated. The hearts were histologically examined.

RESULTS:

Although significant changes in myocardial workload were observed after the induction of brain death and during support and withdrawal of dopamine in both groups, the initial PCr/ATP ratio of 2.00+/-0.12 and the contents of PCr and ATP did not vary significantly. Histologically identified sub-endocardial hemorrhage was observed in 3 of 6 of the brain-dead animals and in 1 of 6 of the control animals.

CONCLUSIONS:

High dosages of dopamine in the treatment of brain death-related reduced myocardial workload do not alter PCr/ATP ratios and the contents of PCr and ATP of the potential donor heart despite histologic damage.

• Authors: G J Bruinsma, M G Nederhoff, C W van de Kolk, M C de Groot, P J Slootweg, J J Bredée, T J Ruigrok, C J Van Echteld
• Journal: The Journal of heart and lung transplantation : the official publication of the International Society for Heart Transplantation (J Heart Lung Transplant) Vol. 18 Issue 12 Pg. 1189-97 (Dec 1999) ISSN: 1053-2498 [Print] United States
• PMID: 10612377 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• Phosphorus Radioisotopes
• Phosphocreatine
• Adenosine Triphosphate
• Dopamine

Topics

• Adenosine Triphosphate (analysis)
• Animals
• Brain Death (metabolism)
• Cats
• Dopamine (administration & dosage, pharmacology)
• Energy Metabolism
• Heart (drug effects)
• Heart Transplantation
• Magnetic Resonance Spectroscopy
• Male
• Myocardium (chemistry, metabolism)
• Phosphocreatine (analysis)
• Phosphorus Radioisotopes