In hypertensive patients, combined ETA and ETB blockade increased forearm blood flow by 63% compared to 33% with ETA blockade alone (P=0.006).
Does intraarterial infusion of endothelin receptor blockers increase forearm blood flow in patients with essential hypertension?
Patients with essential hypertension exhibit increased vascular endothelin activity, and combined ETA/ETB blockade produces greater vasodilation than ETA blockade alone.
Absolute Event Rate: 63% vs 33%
p-value: p=0.006
We investigated the possible role of endothelin in the increased vasoconstrictor tone of hypertensive patients using antagonists of endothelin receptors. Forearm blood flow (FBF) responses (strain-gauge plethysmography) to intraarterial infusion of blockers of endothelin-A (ETA) (BQ-123) and endothelin-B (ETB) (BQ-788) receptors, separately and in combination, were measured in hypertensive patients and normotensive control subjects. In healthy subjects, BQ-123 alone or in combination with BQ-788 did not significantly modify FBF (P=0.78 and P=0.63, respectively). In hypertensive patients, in contrast, BQ-123 increased FBF by 33+/-7% (P<0.001 versus baseline), and the combination of BQ-123 and BQ-788 resulted in a greater vasodilator response (63+/-12%; P=0.006 versus BQ-123 alone in the same subjects). BQ-788 produced a divergent vasoactive effect in the two groups, with a decrease of FBF (17+/-5%; P=0.004 versus baseline) in control subjects and transient vasodilation (15+/-7% after 20 minutes) in hypertensive patients (P<0.001, hypertensives versus controls). The vasoconstrictor response to endothelin-1 was slightly higher (P=0.04) in hypertensive patients (46+/-4%) than in control subjects (32+/-4%). Our data indicate that patients with essential hypertension have increased vascular endothelin activity, which may be of pathophysiological relevance to their increased vascular tone. In these patients, nonselective ETA and ETB blockade seems to produce a greater vasodilator effect than selective ETA blockade.
Cardillo et al. (Mon,) conducted a other in Essential Hypertension. Combination of BQ-123 (ETA blocker) and BQ-788 (ETB blocker) vs. BQ-123 alone was evaluated on Forearm blood flow (FBF) response (p=0.006). In hypertensive patients, combined ETA and ETB blockade increased forearm blood flow by 63% compared to 33% with ETA blockade alone (P=0.006).