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| Slide Lecture Programs |
| 2000 Core Curriculum |
| The endothelium: New insights into the origins and treatment of CAD |
August 31, 2000
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Heart failure: Role of ACE inhibition
- Another way of assessing b-receptor function is to determine b-receptor density. Down-regulation of receptors is evident by a decrease in the number of receptors per cell. Whole blood samples from healthy controls had about 1000 b-receptors per lymphocyte. Samples from patients with severe heart failure had only about 25% of that number.
- Townend and colleagues demonstrated that after 16 weeks of quinapril therapy, b-receptor density in patients with heart failure increased significantly, from approximately 240 receptors per cell to just under 900 receptors per cell (P < .05).73
- To confirm the linkage beween these changes and clinical effects, Townend and Davis showed that improved b-cell density was accompanied by improved hemodynamic responses. Following 16-weeks of quinapril, the same 12 patients had significant improvements in cardiac index, stroke volume, and cardiac output during sub-maximal exercise testing and dobutamine infusion.
- They concluded that ACE inhibitors cause lymphocyte b-receptor upregulation in heart failure. This is associated with an improved cardiac pumping capacity in response to b-agonist stimulation. They also concluded that b-receptor upregulation may be an important mechanism for the therapeutic effects of ACE inhibition in patients with chronic heart failure.
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