OBJECTIVES: The purpose of this study was to compare the effects of orthostatic stress on cardiovascular stability in heart transplant recipients early and late after transplantation and in healthy controls. BACKGROUND: After transplantation, cardiac reinnervation is heterogeneous, with reports of sympathetic reinnervation after 5 months and parasympathetic reinnervation after 2 to 3 years. METHODS: Sixteen heat transplant recipients early (less than 5 months) after transplantation, 17 recipients late (1 year or more) after transplantation, and 16 matched healthy controls were subjected to 45 minutes of passive upright tilt, with the following variables measured before, during, and after the procedure: cardiac output, heart rate, stroke volume, mean arterial pressure, systemic vascular resistance, and plasma norepinephrine. RESULTS: At rest, heart rate (p < 0.0005) and mean arterial pressure (p = 0.003) were higher, and stroke volume was lower (p < 0.0005), in transplant recipients than they were in controls. With orthostasis, heart rate increased by 30% in controls and by 23% in the late posttransplantation group compared with 13% in the early posttransplantation group (p = 0.028); drop in stroke volume was three times more among controls than among those in either transplantation group (p < 0.001); late transplant recipients had higher norepinephrine increases than did the other two groups (p = 0.012). CONCLUSION: With the exception of heart rate, patterns of hemodynamic response to orthostatic stress after transplantation remain consistent over time and differ from controls. Among transplant recipients, higher mean arterial pressure mitigates the force of gravity and prevents drops in stroke volume. Clinicians may anticipate that transplant recipients will tolerate postural maneuvers well. Later after transplantation, however, orthostatic tolerance is associated with increased norepinephrine release, consistent with enhanced sympathoactivation.
|Number of pages||13|
|Journal||Heart and Lung: Journal of Acute and Critical Care|
|State||Published - 1996|
Bibliographical noteFunding Information:
O rthotopic heart transplantation has bb ecome an established treatment for advanced heart failure. More than 3200 procedures are now performed annually, and 30,000 procedures have been performed to date worldwide.1 Nurses routinely care for orthotopic heart transplant recipients in the immediate From the University of California, Los Angeles, Schools of Nursing and Medicine. Supported by grants from the National Institutes of Health National Institute of Nursing (predoctoral NRSA), and the Universityo f California, Los Angeles, School of Nursing.
ASJC Scopus subject areas
- Pulmonary and Respiratory Medicine
- Critical Care and Intensive Care Medicine
- Cardiology and Cardiovascular Medicine