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Relationship between coronary function by positron emission tomography and temporal changes in morphology by
M Allen-Auerbach1, H Schöder, J Johnson
1Department of Molecular and Medical Pharmacology, UCLA School of Medicine, Los Angeles, California 90095-6948, USA.
Insights
Abnormalities in endothelial independent myocardial blood flow, detected by positron emission tomography (PET) one to two years after heart transplantation, correlate with transplant vasculopathy progression. This non-invasive test may predict graft failure in transplant recipients.
Area of Science:
- Cardiology
- Transplantation Medicine
- Medical Imaging
Background:
- Transplant coronary vasculopathy is a primary cause of graft loss and mortality in heart transplant recipients.
- A non-invasive method to assess coronary function and predict disease progression is needed.
Purpose of the Study:
- To investigate the correlation between coronary vasomotion and vasodilatory capacity, assessed by positron emission tomography (PET), and the progression of transplant vasculopathy.
Main Methods:
- Nineteen heart transplant patients underwent baseline PET and intravascular ultrasound (IVUS) 18 months post-transplant, with a follow-up IVUS 15 months later.
- Coronary vasomotion was assessed using cold pressor testing (endothelial-dependent).
- Vasodilatory capacity was assessed using intravenous dipyridamole (endothelial-independent).
Main Results:
- Myocardial blood flow was elevated in patients compared to controls and did not increase during cold pressor testing.
- Dipyridamole-induced flow reserve was reduced in patients.
- Normalized flow reserve correlated with changes in vessel area and lumen diameter.
Conclusions:
- Abnormalities in endothelial-independent myocardial blood flow, detected by PET, are linked to morphological signs of transplant vasculopathy progression.
- PET assessment of myocardial flow may serve as a non-invasive predictor of disease course in heart transplant recipients.
Background:
Transplant coronary vasculopathy is one of the major causes of graft failure and death in cardiac transplant recipients. A non-invasive test of coronary function to predict the course of this disease would be desirable.
Methods:
To determine whether the degree of abnormalities in endothelial dependent coronary vasomotion (cold pressor testing) or endothelial independent vasodilatory capacity (intravenous dipyridamole) as determined by positron emission tomography (PET) one to two years after heart transplantation is correlated with the course of transplant vasculopathy. Nineteen patients had baseline PET and intravascular ultrasound studies (IVUS) at 18 +/- 6 months after cardiac transplantation and a follow up IVUS study 15 +/- 5 months later.
Results:
Myocardial blood flow was higher in patients than in healthy controls (p < 0.002) but increased during cold pressor testing only in controls (p < 0.005). Myocardial blood flow normalized to the rate pressure product declined in patients (p < 0.001). Dipyridamole-induced hyperemic blood flow and the flow reserve normalized to the resting rate pressure product were lower in patients than in controls (p < 0.001 and p < 0.01). The normalized flow reserve was correlated with changes in total vessel area (r = 0.55; p = 0.02) and lumen diameter (r = 0.52; p < 0.05).
Conclusion:
These findings suggest that the degree of abnormalities in endothelial independent myocardial flow as detected by PET one to two years after transplantation is associated with morphological indices of disease progression by IVUS.