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Effect of calcium channel antagonists on renal function in hypertensive heart transplant recipients
Insights
Calcium channel antagonists improved kidney function and lowered blood pressure in heart transplant patients previously treated with angiotensin-converting enzyme inhibitors. This switch in medication offers a potential benefit for managing hypertension and nephrotoxicity post-transplant.
Area of Science:
- Nephrology
- Cardiology
- Pharmacology
Background:
- Orthotopic heart transplant recipients on cyclosporine-based immunosuppression frequently develop hypertension and nephrotoxicity.
- Cyclosporine-induced nephrotoxicity involves afferent glomerular arteriolar vasoconstriction.
- Angiotensin-converting enzyme inhibitors (ACEI) may decrease glomerular filtration rate in cyclosporine-treated patients.
Purpose of the Study:
- To evaluate the effect of switching from ACEI to calcium channel antagonists (CCAs) on renal function in heart transplant patients.
- To test if CCAs can improve glomerular filtration rate in this patient population.
Main Methods:
- Retrospective chart review of heart transplant patients switched from ACEI to CCAs for hypertension management.
- Renal function assessed by serum creatinine, blood urea nitrogen, and creatinine clearance before and after the switch.
- Blood pressure measured on two occasions before and after the medication change.
- Paired Student t-test used for data analysis.
Main Results:
- Serum blood urea nitrogen and creatinine levels significantly decreased with CCA treatment (p < 0.05).
- Creatinine clearance showed a significant increase, from 56.4 +/- 19.3 ml/min with ACEI to 71.06 +/- 23.77 ml/min with CCAs (p < 0.005).
- Mean arterial pressure decreased by 5 mm Hg after switching to CCAs.
Conclusions:
- Calcium channel antagonists demonstrate a beneficial effect on renal function in heart transplant recipients treated with ACEI.
- Switching from ACEI to CCAs can improve glomerular filtration rate and reduce blood pressure in this population.
- CCAs represent a viable therapeutic option for managing hypertension and associated nephrotoxicity in heart transplant patients.
Abstract:
Orthotopic heart transplant recipients treated with immunosuppressive regimens based on cyclosporine have a high incidence of hypertension. Cyclosporine-induced nephrotoxicity characterized by afferent glomerular arteriolar vasoconstriction also develops in these patients. Calcium channel antagonists produce afferent glomerular arteriolar vasodilation. Angiotensin-converting enzyme inhibitors (ACEI) dilate the efferent arteriole and have been suggested to decrease glomerular filtration rate in subjects taking cyclosporine. To test the hypothesis that calcium channel antagonists would improve glomerular filtration rate in heart transplant patients receiving ACEI treatment, we reviewed the charts of our patients whose treatment for hypertension had been changed from an ACEI to a calcium channel antagonist. A change in renal function was assessed by the average of serum creatinine level, blood urea nitrogen, and creatinine clearance within 3 months before and after the change from ACEI to calcium channel antagonist. Blood pressure was assessed on two different occasions before and after conversion to calcium channel antagonist. The data were analyzed by a paired Student t test. Serum blood urea nitrogen and creatinine levels decreased significantly when patients were treated with calcium channel antagonists (p < 0.05). Creatinine clearance increased in all patients when the treatment was converted to a calcium channel antagonist (CCA) (ACEI = 56.4 +/- 19.3 ml/min versus CCA = 71.06 +/- 23.77, N = 9; p < 0.005). A 5-mm Hg decrease occurred in mean arterial pressure when treatment was changed from ACEI to calcium channel antagonists.(ABSTRACT TRUNCATED AT 250 WORDS)