This study was performed to examine the influence of isoflurane anesthesia on the pulsatility index (PI) and the peak systolic velocity (PSV) of the blood flow in the basilar artery of dogs by duplex Doppler ultrasonography. Twelve healthy dogs were used to measure the PI and the PSV under the conscious state and isoflurane anesthesia. The pulsatility index (PI) and the peak systolic velocity (PSV) in the basilar artery were measured five times with random intervals. The blood pressure was measured. The PI and PSV values in dogs under isoflurane anesthesia were 1.37 +/- 0.32 and 72 +/- 19 cm/sec, whereas those in the conscious dogs were 1.37 +/- 0.13 and 81 +/- 16 cm/sec, respectively. The indirect mean arterial systolic and diastolic pressures under isoflurane anesthesia were 107 and 51 mmHg, whereas those in the conscious dogs were 133 and 74 mmHg. Though the isoflurane is generally known to induce hypotension, there were no significant differences in the PI and PSV between the isoflurane-anesthetized and the conscious dogs. In conclusion, the isoflurane anesthesia did not influence the PI and PSV in the basilar artery of dogs.
Anesthetics, Inhalation/*pharmacology ; Animals ; Basilar Artery/drug effects/*ultrasonography ; Blood Flow Velocity/drug effects/veterinary ; Blood Pressure/drug effects ; Cerebrovascular Circulation/drug effects ; Dogs/*physiology ; Female ; Isoflurane/*pharmacology ; Male ; Pulsatile Flow/drug effects ; Ultrasonography, Doppler, Duplex/veterinary

BACKGROUND: Increased aortic stiffness is a independent risk factor of cardiovascular disease in patients with hypertension. Acute changes of the heart rate (HR) have been reported not to affect the aortic stiffness in pacing. However, it is unknown whether acute changes in HR caused by sympathomimetics can affect the aortic stiffness in patients with hypertension. We investigated the effect of acute changes in HR produced by isoproterenol on the aortic stiffness in 17 hypertensive patientss (mean age: 59 +/- 9 years). METHODS: All vasoactive drugs were discontinued at least 3 days before the study. The carotid-tofemoral pulse wave velocity (PWV) was measured by the foot-to-foot method. The pulse waves were recorded at the baseline and at every increase of HR by 5 to 10 bpm with a gradual increase of the dose of isoproterenol. The blood pressures and HR were measured simultaneously. For the analysis, HR, PWV, compliance (C), and compliance index (Ci) were converted as percent changes (delta) from the baseline values. Percent changes of the parameters of the aortic stiffness, i.e., delta PWV, delta C, and delta Ci, were grouped by every 10% increase in delta HR. RESULTS: There was no significant difference among groups in delta PWV, delta C and delta Ci (p> 0.05 for each of the group). The regression analysis showed no significant correlation of delta HR with delta PWV and delta C (r=0.18, 0.13 respectively, p> 0.05 for each). delta Ci had a poor correlation with delta HR (r=0.22, p< 0.05). However, only 4.6% of delta Ci could be referred to delta HR (r2=0.046). CONCLUSION: Aortic stiffness was not affected by acute changes in HR produced by isoproterenol which suggests that it is not necessary to consider acute changes in HR when measuring aortic PWV.
Aged ; Aorta/*drug effects ; Chest Pain/etiology ; Coronary Disease/complications ; Elasticity/drug effects ; Female ; Heart Rate/*drug effects ; Human ; Hypertension/complications/*physiopathology ; Isoproterenol/*pharmacology ; Linear Models ; Male ; Middle Aged ; Pulsatile Flow/physiology ; Sympathomimetics/*pharmacology

OBJECTIVE: To investigate the effects of sildenafil citrate (Viagra) on the vertebral artery blood flow of patients with vertebro-basilar insufficiency (VBI) using color duplex sonography (CDS). MATERIALS AND METHODS: The study included 21 patients with VBI (aged 31-76; mean 61.0 +/- 10.5 yrs). We administered a 50 mg oral dose of sildenafil citrate to all patients. Next, we measured the peak systolic velocity (Vmax), end diastolic velocity (Vmin), resistive index (RI), pulsatility index (PI), diameter, area, and flow volume (FV) of vertebral arteries using CDS before the administration of sildenafil citrate; 45 minutes after, and 75 minutes after administration. Statistical testing was performed using SPSS for windows version 11.0. The statistical test used to determine the outcome of the analysis was the repeated measures analysis of variance (ANOVA) test. RESULTS: Compared to the baseline values, the vertebral artery diameter, area, and FV increased significantly following the administration of sildenafil citrate. The diameter, area and FV increased from 3.39 mm at 45 minutes to 3.64 mm at 75 minutes, 9.43 cm2 to 10.80 cm2 at 45 minutes and 10.81 cm2 at 75 minutes, as well as from 0.07 L/min at baseline to 0.09 L/min at 45 minutes and unchanged at 75 minutes, respectively. CONCLUSION: Sildenafil citrate elicited a significant effect on vertebral artery diameter, area and FVs.
Adult ; Aged ; Blood Flow Velocity/drug effects ; Female ; Humans ; Male ; Middle Aged ; Piperazines/*pharmacology ; Pulsatile Flow/drug effects ; Purines/pharmacology ; Sulfones/*pharmacology ; *Ultrasonography, Doppler, Color ; Vascular Resistance/drug effects ; Vasodilator Agents/*pharmacology ; Vertebral Artery/*drug effects/physiopathology/ultrasonography ; Vertebrobasilar Insufficiency/*physiopathology/ultrasonography

BACKGROUND/AIMS: We assessed changes in hemodynamic and arterial stiffness parameters following reductions of dialysate calcium concentrations in patients undergoing hemodialysis. METHODS: In this prospective study, 20 patients on maintenance hemodialysis (10 females, 10 males) with dialysate calcium concentrations of 1.75 mmol/L were enrolled. At the start of the study, the dialysate calcium level was lowered to 1.50 mmol/L. Serial changes in biochemical, hemodynamic, and arterial stiffness parameters, including pulse wave velocity (PWV) and augmentation index (AIx), were assessed every 2 months for 6 months. We also examined changes in the calcification-inhibitory protein, serum fetuin-A. RESULTS: During the 6-month study period, serum total calcium and ionized calcium decreased consistently (9.5 +/- 1.0 to 9.0 +/- 0.7, p = 0.002 vs. 1.3 +/- 0.1 to 1.1 +/- 0.1, p = 0.035). Although no apparent changes in blood pressure were observed, heart-femoral PWW (hf-PWV) and AIx showed significant improvement (p = 0.012, 0.043, respectively). Repeated-measures ANOVA indicated a significant effect of lowering dialysate calcium on hf-PWV (F = 4.58, p = 0.004) and AIx (F = 2.55, p = 0.049). Accompanying the change in serum calcium, serum fetuin-A levels significantly increased (95.8 +/- 45.8 pmol/mL at baseline to 124.9 +/- 82.2 pmol/mL at 6 months, p = 0.043). CONCLUSIONS: Lowering dialysate calcium concentration significantly improved arterial stiffness parameters, which may have been associated with upregulation of serum fetuin-A.
Aged ; Analysis of Variance ; Ankle Brachial Index ; Arteries/*drug effects/physiopathology ; Biological Markers/blood ; Blood Pressure/drug effects ; Calcium/*administration & dosage/adverse effects ; Compliance ; Female ; Hemodialysis Solutions/*administration & dosage/adverse effects/chemistry ; Humans ; Male ; Middle Aged ; Prospective Studies ; Pulsatile Flow/*drug effects ; *Renal Dialysis ; Republic of Korea ; Time Factors ; Treatment Outcome ; alpha-2-HS-Glycoprotein/metabolism