Table 3.

Hemodynamic responses to α₁-adrenergic agonist (phenylephrine) administration at rest

			Phenylephrine Concentration, μg·min−1·dl thigh volume−1
	BL	Propranolol (5 mg)	0.015	0.03	0.06	0.12	0.24
Control
Leg blood flow, ml/min	253 ± 33	227 ± 33#	212 ± 33	185 ± 33#	174 ± 33#	142 ± 24#	141 ± 19#
Leg vascular conductance, ml·min−1·mmHg−1	3.0 ± 0.4	2.7 ± 0.4#	2.5 ± 0.4	2.2 ± 0.4#	2.1 ± 0.4#	1.6 ± 0.3#	1.6 ± 0.2#
Leg perfusion pressure, mmHg	85 ± 3	85 ± 3	83 ± 3	84 ± 3	85 ± 3	86 ± 3	87 ± 3
CFA diameter
cm	1.02 ± 0.06	1.02 ± 0.06	1.01 ± 0.06	0.99 ± 0.06#	0.97 ± 0.07#	0.97 ± 0.07#	0.93 ± 0.7#
%Δ		0.0 ± 0.1	−0.6 ± 0.4	−3.0 ± 1.7	−4.8 ± 2.5#	−6.8 ± 2.9#	−9.6 ± 3.5#
HR, beats/min	60 ± 4	54 ± 3#	54 ± 2	53 ± 3	53 ± 2	51 ± 2	52 ± 2
HFrEF
Leg blood flow, ml/min	218 ± 26		215 ± 20	202 ± 22	189 ± 19	179 ± 16#	174 ± 18#
Leg vascular conductance, ml·min−1·mmHg−1	2.8 ± 0.3		2.8 ± 0.3	2.5 ± 0.3	2.3 ± 0.2#	2.2 ± 0.3#	2.1 ± 0.2#
Leg perfusion pressure, mmHg	80 ± 5		80 ± 5	82 ± 5	82 ± 5	83 ± 4	82 ± 3
CFA diameter
cm	0.88 ± 0.05		0.87 ± 0.05	0.86 ± 0.05	0.84 ± 0.05#	0.82 ± 0.05#	0.80 ± 0.06#
%Δ			−1.2 ± 0.3	−2.6 ± 0.6	−4.3 ± 0.8#	−6.2 ± 1.0#	−8.8 ± 2#
HR, beats/min	67 ± 2		65 ± 2*	66 ± 3*	67 ± 2*	68 ± 3*	72 ± 6*

Values are means ± SE. In controls, propranolol was administered immediately before the phenylephrine dose response (0.015–0.24 μg·min⁻¹·dl thigh volume⁻¹, 2 min per dose) to minimize β-adrenergic effects. BL, baseline; HR, heart rate; CFA, common femoral artery; HFrEF, heart failure with reduced ejection fraction.

^*P < 0.05 vs. control;

^#P < 0.05 vs. preinfusion.