Effects of canrenoate potassium, an aldosterone antagonist on portal hemodynamics in patients with compensated liver cirrhosis

BACKGROUND/AIMS: Long-term administration of spironolactone is reported to reduce portal pressure in cirrhotic patients. We examined the effects of acute administration of canrenoate potassium, an aldosterone antagonist, on portal hemodynamics in compensated cirrhotic patients using noninvasive duplex Doppler ultrasonography. MATERIALS AND METHODS: Baseline values were obtained in the fasting state, and then 200mg of canrenoate potassium in 10ml of saline solution was intravenously administered to 22 patients, whereas 10ml of saline solution was administered as a placebo to 8 patients. RESULTS: The portal cross-sectional area, portal blood velocity and portal blood flow decreased by 5.3 +/- 9.2, 10.4 +/- 8.7% and 13.0 +/- 12.4%, respectively at the nadir 60min after administration and these decreases persisted until 120min. Placebo did not affect these parameters of portal hemodynamics. Eleven responders, who had a more than 10% drop in portal blood flow 60min after administration, had significantly higher levels of plasma aldosterone than 8 non responders who had less than 10% drop. The reduction rate of portal blood flow was closely correlated with plasma aldosterone level. CONCLUSIONS: These findings suggest that aldosterone antagonist directly causes a reduction in portal blood flow, probably through inhibition of aldosterone-induced vasoconstrictive action.     

Quality assessment and vascular disease: the analytic imperatives confronting vascular surgeons in the new era

Not much is known about the relationship between portal hemodynamics and the grades of cirrhosis. Using pulsed Doppler ultrasonography, we studied portal vein diameter, portal flow velocity, and portal blood flow rate in 37 patients with liver cirrhosis (11 Child's A, 13 Child's B, and 13 Child's C) and 10 healthy controls. There was no difference in the maximum inner diameter of the portal vein in cirrhotics and controls. However, there was a significant decrease in the portal flow velocity in patients with Child's C cirrhosis, as compared to controls and patients with Child's A and Child's B cirrhosis. The portal blood flow rate in Child's B and Child's C cirrhosis was also significantly less as compared to controls and patients with Child's A cirrhosis. Patients with ascites and encephalopathy had significantly lower portal flow velocities and blood flow rate as compared to those without ascites and encephalopathy, respectively. This study indicates that portal flow significantly decreased in cirrhotic patients with worsening Child's grade of cirrhosis.     

Ehlers-Danlos syndrome and congenital heart anomalies

OBJECTIVE: To study the effects of octreotide on portal pressure and the relationship between the portal pressure and portal hemodynamics measured by color Doppler. METHODS: A high portal resistance model by injecting bletilla hyacinthina was established in 6 dogs. The portal pressure and portal hemodynamics studied by color Doppler were measured respectively by two investigators before and after injecting octreotide into the peripheral vein. RESULTS: Portal hypertension was caused by injecting bletilla hyacinthina into the portal vein. The portal pressure was reduced and portal venous velocity increased after injecting octreotide into the peripheral vein. There was a significant negative correlation between the portal pressure and portal venous velocity. CONCLUSION: Color Doppler is helpful in evaluating the effects of octreotide on the portal pressure.     

Disruption of p53 function in immortalized human cells does not affect survival or apoptosis after taxol or vincristine treatment

OBJECTIVE: We assessed the feasibility of contrast-enhanced color Doppler, power Doppler, and spectral duplex sonography for visualization and quantification of flow through transjugular intrahepatic portosystemic shunts (TIPS) in patients in whom the baseline sonographic evaluation was unsatisfactory. SUBJECTS AND METHODS: Thirty-three patients underwent color Doppler, power Doppler, and spectral duplex sonography after TIPS insertion or before TIPS revision (mean time interval +/- SD, 1 +/- 1 day). All sonograms were obtained before and after patients received echo-enhancing contrast material. Sonography was evaluated with regard to presence or absence of flow in the mid portion, portal segment, and hepatic segment of the shunt. The maximal peak velocity was measured in the mid portion of the shunt. For identifying and quantifying stenoses, the percentage of luminal diameter reduction was calculated at the tightest part of the shunt. Shunt angiography and measurements of portosystemic pressure gradients were independently evaluated and compared with the sonographic findings. RESULTS: Flow visualization on unenhanced color Doppler sonography was significantly improved through the use of power Doppler sonography and contrast-enhanced color Doppler and power Doppler sonography (p < .01). Between contrast-enhanced power Doppler and contrast-enhanced color Doppler sonography, a significant difference was found in the portal and hepatic segments (p < .05). All shunt stenoses (n = 8) and occlusions (n = 3) were revealed by power Doppler sonography, whereas color Doppler sonography failed to reveal six of eight stenoses. Compared with unenhanced sonography, the quality of spectral duplex sonography was improved in eight patients after contrast enhancement (p < .05). Maximal peak velocity ranged from 54 to 252 cm/sec (mean +/- SD, 132.7 +/- 52.1 cm/sec) in normal shunts and from 24.5 to 70.0 cm/sec (mean +/- SD, 45.0 +/- 18.9 cm/sec) in stenosed shunts. No correlation was found between maximal peak velocity and portosystemic pressure gradients (r = .28). CONCLUSION: Unenhanced power Doppler and contrast-enhanced color and power Doppler sonography can be helpful in the assessment of TIPS status in patients who previously underwent unsatisfactory sonography. These techniques may allow anatomic evaluation and quantification of shunt stenosis in most patients. Contrast enhancement may also considerably improve the quality of spectral duplex sonography.     

Changes in blood flow velocity and diameter of the middle cerebral artery during hyperventilation: assessment with MR and transcranial Doppler sonography

PURPOSE: To compare blood flow velocity changes within the middle cerebral artery (MCA) during hyperventilation, as measured with by both transcranial Doppler sonography and MR imaging, with the diameter of the MCA as measured with MR imaging alone. METHODS: The studies were performed in six healthy volunteers ranging in age from 22 to 31 years (mean, 27 years). Transcranial Doppler sonography was carried out with a range-gated 2-MHz transducer. MR examinations were done on a 1.5-T imaging unit. MR angiography was performed using the time-of-flight technique. MR flow measurements were carried out by using the phase-mapping technique with an ECG-triggered phase-contrast sequence. RESULTS: During hyperventilation, the mean blood flow velocity of the proximal MCA declined by 49.6% +/- 5.7 (mean +/- standard deviation) as measured with Doppler sonography, and by 47% +/- 4.6 as measured with MR flow calculation. The diameter of the MCA (3.4 +/- 0.3 mm) remained unchanged on MR imaging studies (3.3 +/- 0.3 mm). CONCLUSION: We found a good correlation between relative flow velocity changes measured by transcranial Doppler sonography and MR techniques. MR imaging revealed no significant changes in the diameter of the proximal MCA during normal versus hyperventilation. Relative changes in flow velocity in the MCA would thereby reflect relative changes in cerebral blood flow, at least during hyperventilation.     

Anti-GBM glomerulonephritis in mice lacking nitric oxide synthase type 2

To determine the relationship between quantitative Doppler parameters of portal, hepatic, and splanchnic circulation and hepatic venous pressure gradient (HVPG), variceal size, and Child-Pugh class in patients with alcoholic cirrhosis, we studied forty patients with proved alcoholic cirrhosis who underwent Doppler ultrasonography, hepatic vein catheterization, and esophagoscopy. The following Doppler parameters were recorded: time-averaged mean blood velocity, volume flow of the main portal vein flow, and resistance index (RI) of the hepatic and of the superior mesenteric artery. Doppler findings were compared with HVPG, presence and size of esophageal varices, and Child-Pugh class. There was a significant inverse correlation between portal velocity and HVPG (r = -.69), as well as between portal vein flow and HVPG (r = -.58). No correlation was found between RI in the hepatic artery or superior mesenteric artery and HVPG. No correlation was found between portal vein measurements and presence and size of varices. Severe liver failure was associated with lower portal velocity and flow. In patients with alcoholic cirrhosis, only portal vein blood velocity and flow, but neither hepatic nor mesenteric artery RI, are correlated to the severity of portal hypertension and to the severity of liver failure.     

Blink reflex recovery cycle in patients with blepharospasm unilaterally treated with botulinum toxin

To study the role of arterial blood dynamics in the thrombogenesis of thrombin-induced experimental retinal vein obstruction, the retinal blood flow velocity was evaluated using scanning laser ophthalmoscopic fluorescein videoangiography in an experimental rabbit retinal vein obstruction model. Retinal vein obstruction was made by transadventitial direct instillation of thrombin to the retinal vessels from the vitreous side. The blood flow velocity in the retinal artery and vein was estimated by measuring the passing velocity of the flow head of the dye bolus and venous filling time, respectively. 23 animals were treated with thrombin and compared with 18 controls not treated. In the control group retinal artery blood flow velocity and retinal venous fluorescein filling time was 5.3 +/- 1.1 mm/sec (mean +/- standard deviation) and 6.2 +/- 1.2 sec, respectively. In the treated group the values were 5.7 +/- 1.3 mm/sec and 5.8 +/- 1.0 sec before the thrombin administration, and 3.0 +/- 0.9 mm/sec at 24 hours after its administration, and 5.7 +/- 2.0 sec and 4.0 +/- 1.5 mm/sec and 4.5 +/- 1.4 sec at 48 hours after the administration. These results indicate that a decrease in retinal artery blood flow velocity is strongly involved in the thrombogenesis in thrombin-induced experimental retinal vein obstruction.     

Effects of beta-adrenergic blockers on retinal circulation

We evaluated the effects of 0.5% betaxolol hydrochloride and 0.5% timolol maleate on retinal blood flow. We measured the diameter of the retinal artery (Da) and vein (Dv), and retinal venous blood flow rate (V) in 8 healthy young volunteers by laser speckle velocimetry before and after the application of betaxolol or timolol topically to both eyes daily for one week. There were no any significant changes. Da before and after the application of betaxolol was 114.2 +/- 6.3 (mean +/- standard deviation) microns and 115.6 +/- 6.7 microns and before and after the application of timolol, 117.5 +/- 12.7 microns and 101.3 +/- 9.5 microns. Dv before and after the application of betaxolol was 149.5 +/- 11.1 microns and 148.4 +/- 13.3 microns, and before and after the application of timolol 148.5 +/- 9.2 microns and 146.2 +/- 10.3 microns. V before and after the application of timolol was 12.3 +/- 2.6 mm/s and 12.6 +/- 2.4 mm/s, and before and after the application of betaxolol, 11.6 +/- 1.5 mm/s and 11.4 +/- 2.1 mm/s. Thus one-week application of the beta-blockers, betaxolol and timolol did not change the retinal arterial or venous blood flow.     

Vasodilatory effects of propylthiouracil in patients with alcoholic cirrhosis

BACKGROUND/AIMS: An experimental study has shown that propylthiouracil increases portal blood flow in normal rats. Whether propylthiouracil has a similar effect in patients with alcoholic cirrhosis remains to be demonstrated. The aim of this study was to evaluate the effects of oral propylthiouracil (300 mg) on systemic and portal hemodynamics in patients with alcoholic cirrhosis. METHODS: Plasma propylthiouracil levels were also measured by high performance liquid chromatography in five patients with alcoholic cirrhosis. In eight patients with cirrhosis, mean arterial pressure, cardiac output and portal blood flow were evaluated before and after placebo and propylthiouracil administration. Hemodynamic measurements were performed by the Doppler technique. The plasma peak level of propylthiouracil was achieved at 1.4 +/- 0.1 h in patients with alcoholic cirrhosis. This time was chosen to express hemodynamic changes. RESULTS: Propylthiouracil administration caused a significant increase in portal blood flow (+16.5%, p < 0.05) in patients with alcoholic cirrhosis. This effect was associated with a mild and significant rise in cardiac output (from 5.8 +/- 0.2 to 6.1 +/- 0.3 l/min, p < 0.05) and a decrease in peripheral vascular resistance (from 1171 +/- 69 to 1070 +/- 67 dyn . s-1 . cm-5, p < 0.01). A significant correlation was observed between changes in portal blood flow and peripheral vascular resistance (r = 0.79, p < 0.05). No significant changes were observed after placebo. CONCLUSIONS: Our findings show that propylthiouracil has a vasodilatory effect in patients with alcoholic cirrhosis. We postulate that this effect could be the mechanism by which propylthiouracil decreases hypermetabolic state, and increases oxygen delivery to the liver, in patients with alcoholic liver diseases.     

Human isosporiasis in an AIDS patient--report of first case in Malaysia

Splanchnic and systemic hemodynamics and plasma levels of aldosterone, glucagon and plasma renin were investigated in 12 patients with advanced cirrhosis before and 2 wk (14.6 +/- 2.8 days) and 2 mo (60.8 +/- 10.5 days) after orthotopic liver transplantation. Liver transplant was followed by significant (p < 0.01) changes in systemic hemodynamics at 2 wk, with a marked reduction in cardiac index (4.9 +/- 0.8 vs. 3.7 +/- 0.7 L/min.m2) and increases in mean arterial pressure (79 +/- 8 vs. 101 +/- 11 mm Hg) and peripheral vascular resistance (721 +/- 149 vs. 1,274 +/- 253 dyn.sec.cm-5). Two months after liver transplant, we saw further significant increases in peripheral vascular resistance (1,700 +/- 341 dyn.sec.cm-5; p < 0.05) without changes in cardiac index. Hepatic venous pressure gradient, very high before transplantation, was normal 2 wk after liver transplant (18.7 +/- 3.0 vs. 2.1 +/- 0.8 mm Hg; p < 0.01). Hepatic blood flow rose markedly from 1.03 +/- 0.46 to 2.25 +/- 0.79 L/min (p < 0.01) and was still elevated at 2 mo (1.84 +/- 0.74 L/min). Azygos blood flow had not changed after 2 wk with respect to pretransplant values (0.65 +/- 0.26 vs. 0.69 +/- 0.39 L/min) but had decreased significantly at 2 mo (0.39 +/- 0.16 L/min; p < 0.05). The elevated aldosterone, plasma renin and glucagon levels found in our cirrhotic patients before transplantation decreased to near-normal values 2 wk after the procedure. These results suggest that most of the hemodynamic and humoral abnormalities characteristic of advanced cirrhosis are reversed after liver transplant.(ABSTRACT TRUNCATED AT 250 WORDS)     

Exercise hemodynamics in small (< or = 21 mm) aortic valve prostheses assessed by Doppler echocardiography

Exercise Doppler echocardiography was used to assess hemodynamics in 25 patients with a < or = 21 mm aortic valve prosthesis (14 with a Medtronic-Hall 21 mm valve, three with a Medtronic-Hall 20 mm valve, three with a Sorin 21 mm valve, one with a Duromedics 21 mm valve, and four with a Carpentier-Edwards 21 mm valve). A symptom-limited upright bicycle exercise test was performed, and Doppler gradients were recorded during exercise. Gradients increased with exercise from 30 +/- 8/16 +/- 4 mm Hg (peak/mean) at rest to 46 +/- 12/24 +/- 7 mm Hg during exercise; both p < 0.001. Mean exercise gradient exceeded 30 mm Hg in five patients, and the highest mean gradient recorded was 37 mm Hg. Within the group of mechanical valves, gradients at exercise were similar for different types of valves. A linear relationship was found between gradients at rest and during exercise (peak r = 0.75, mean r = 0.77; both p < 0.001). Additional findings were midventricular velocities exceeding 1.5 m/sec in late systole in 10 patients (40%) and intraventricular flow (> or = 0.2 m/sec) toward the apex during isovolumic relaxation in 11 patients (44%). The patients with these velocity patterns had significantly smaller left ventricular cavities (end-diastolic diameter 39.8 +/- 4.8 vs 46.5 +/- 4.2 mm, p < 0.01; end-systolic diameter 24.2 +/- 3.0 vs 28.5 +/- 4.5 mm, p = 0.013).(ABSTRACT TRUNCATED AT 250 WORDS)     

Hemodynamic changes in patients developing effective hypovolemia after total paracentesis

BACKGROUND/AIMS: In many centers paracentesis is considered the treatment of choice for tense ascites. However, the mechanism of effective hypovolemia after paracentesis, the main complication associated with this procedure, remains unknown. In the current study, systemic hemodynamics was sequentially studied before and after total paracentesis in 46 patients with cirrhosis and tense ascites. The aim of the study was to assess the mechanism of effective hypovolemia after paracentesis. METHODS: Plasma renin activity and aldosterone, mean arterial pressure, cardiac output (ECO-Doppler) and systemic vascular resistance were measured before, and 3 h, 6 h and 6 days after total paracentesis associated with plasma volume expansion. RESULTS: Effective hypovolemia after paracentesis (defined as 50% increase in plasma renin activity up to a level over 4 ng x m(-1) x h(-1) at the 6th day after paracentesis) occurred in 20 cases [plasma renin activity increased from 8+/-17 to 19+/-2.7 ng x m(-1) x h(-1)]. In the remaining 26 cases no changes in plasma renin activity [8.5+/-2.4 vs. 8.7+/-2.2 ng x m(-1) x h(-1)] were observed. The amounts of ascitic fluid volume removed were similar. Effective hypovolemia after paracentesis was associated with a significant decrease in mean arterial pressure (89+/-2 vs. 81+/-3 mmHg) and systemic vascular resistance [1263+/-67 vs. 1014+/-80 dyn x s(-1) x cm(-5)] 6 days after treatment. In contrast, no significant changes in these parameters were observed in patients not developing this complication. In the whole group of patients a significant inverse relation was observed between changes in plasma renin activity and in systemic vascular resistance (r=0.74;p< 0.001). CONCLUSIONS: These results indicate that effective hypovolemia after paracentesis in cirrhosis is predominantly due to an accentuation of the arteriolar vasodilation already present in these patients.     

Effect of respiration, exercise, and food intake on hepatic vein circulation

Since the effects of respiration, nutrition, and exercise on blood flow in the hepatic vein are not well understood, the objective of this study was to determine the hemodynamic influence of these factors on hepatic venous circulation using Doppler ultrasonographic tracings. The venous blood flow of the middle hepatic vein was determined during arrested full inspiration, midinspiration, and expiration in 25 healthy subjects. The maximum velocity and the systolic-to-diastolic ratio of the blood flow were measured. The portal vein blood flow velocity was measured in 20 volunteers before and after food intake. The portal vein blood flow and the hepatic vein flow velocity were examined in eight volunteers after exercise. During inspiration, maximum blood flow velocity of the hepatic veins decreased compared to midinspiration (P < 0.001). With expiration the maximum velocity increased (P < 0.001). After food consumption, there was no change in the velocity of the hepatic veins, but the portal vein blood flow increased (P = 0.041). After physical exercises, the maximum velocity of the hepatic venous flow increased, on average, about 148% (P = 0.01), and the portal vein blood flow decreased about 44% (P = 0.027). To achieve standard measurements of hepatic venous blood flow, the state of respiration and physical exertion should be established. The nutritional status had only a minor influence on hepatic vein measurements.     

Coronary flow analysis during autoperfusion angioplasty

BACKGROUND: Autoperfusion balloons are available for the protection of the myocardium during balloon angioplasty. The aortic pressure is the driving force that delivers blood to the distal vessel during balloon inflation. Autoperfusion balloons can achieve sufficient flow rates in vitro. The use of these devices is recommended in high-risk patients in danger of haemodynamic collapse during balloon inflation. The quantity of the distal blood flow during balloon inflation in vivo is still unknown. OBJECTIVES: To measure distal coronary perfusion using Doppler guidewires during percutaneous transluminal coronary angioplasty (PTCA) with autoperfusion balloons. METHODS: Coronary flow velocity was measured with 0.014-inch Doppler guidewires bypassing the autoperfusion balloon in eight patients undergoing elective PTCA (degree of stenosis 74 +/- 7.2%). We used balloons with diameters of 3.0 and 3.5 mm. The coronary diameter at the location of the flow measurements was obtained by quantitative angiography in two planes. Coronary blood flow was calculated as the luminal area multiplied by the average peak flow velocity of the Doppler wire divided by 2. Coronary flow velocity reserve was measured before and after angioplasty by intracoronary injection of adenosine. RESULTS: Coronary blood flow was 35 +/- 11.6 ml/min before PTCA. During average inflation times of 4.6 +/- 0.9 min, coronary blood flow was 19 +/- 3.8 ml/min (P = 0.002) after withdrawing the guidewire in the autoperfusion balloon. Five minutes after angioplasty it increased to 42 +/- 13.5 ml/min (P < 0.001). Four patients had electrocardiographic changes during balloon inflation; three patients reported chest pain. One patient required a stent because of a local dissection. To achieve satisfactory angiographic results (residual stenosis 11 +/- 8.5%), we performed 2.1 +/- 0.78 inflations on average with a cumulative inflation time of 8.8 +/- 3.35 min. Coronary flow velocity reserve increased from 1.3 +/- 0.20 to 2.2 +/- 0.22 (P < 0.001). CONCLUSIONS: Using the autoperfusion balloon we measured a coronary blood flow during angioplasty of 56 +/- 10.3% of the distal perfusion before PTCA. In high-risk patients dependent on adequate coronary perfusion, autoperfusion balloons are not able to provide sufficient distal coronary blood flow during balloon inflation. In these patients active coronary or circulatory support devices are recommended.     

Fusion variations of pancreatic ducts in patients with anomalous arrangement of pancreaticobiliary ductal system

Portal vein flow was recorded by color Doppler sonography in 31 patients with chronic heart failure and 18 control subjects. Compared with patients showing a forward flow (Group A), those with reversed portal vein flow (Group B) had higher prevalence of tricuspid regurgitation (75% vs. 43%), hepatic congestion (100% vs. 30%) and ascites (50% vs. 18%), and showed higher right atrial pressure (25.3 +/- 3.01 mmHg vs. 11.8 +/- 5.75 mmHg, p < 0.01). In controls, portal vein pulsatility ratio was 0.66 +/- 0.08, in Group A it was 0.46 +/- 0.28 (p < 0.01), in Group B -0.60 +/- 0.19 (p < 0.01). Portal vein pulsatility ratio negatively correlated with right atrial pressure (r = -0.87; p < 0.01). In Group A, hepatic congestion, ascites and tricuspid regurgitation were associated with a higher portal vein pulsatility. This study indicates that portal vein pulsatility ratio reflects the level of impairment of the right heart.     

Relationship between haemodynamics and morphology in pulmonary hypertension. A quantitative intravascular ultrasound study

BACKGROUND: Intravascular ultrasound imaging of the pulmonary arteries has been demonstrated to be a reliable method of quantifying vessel diameter, luminal area and pulsatility. Simultaneous measurement of flow velocity and its response to vasodilators allows the relationship between morphology and functional compromise to be studied, especially endothelial dysfunction. METHODS: In 51 patients (mean age = 49.8 +/- 12.6 years, 17 female) we performed right heart catheterization and simultaneous intravascular ultrasound of pulmonary artery branches. The patients were divided in two groups: group 1 with normal pulmonary artery pressure and pulmonary vascular resistance, and group 2 with pulmonary hypertension (peak pulmonary artery pressure > 30 mmHg and/or mean pulmonary artery pressure > 20 mmHg). Vessel wall and lumen were studied using a 2.9 F intravascular ultrasound catheter with a 30 MHz phased array transducer. Measurement of blood flow velocity was accomplished by a Doppler flow wire (0.018 inch). The maximal flow change during acetylcholine infusion (adjusted to 10(-6); 10(-5), and 10(-4) M concentration in the blood vessel) was measured. RESULTS: There were no significant differences between groups 1 and 2 with respect to age (48.5 +/- 14.3 years vs 50.3 +/- 12.3 years; P = ns), gender (4 female/8 male vs 13 female/26 male; P = ns), luminal area of the vessel segment in which the intravascular ultrasound measurements were obtained (11.8 +/- 6.1 mm2 vs 16.7 +/- 14.3 mm2; P = ns), internal diameter (3.9 +/- 1.2 mm vs 4.2 +/- 1.7 mm; P = ns), and external diameter (6.1 +/- 1.3 mm vs 6.9 +/- 2.1 mm; P = ns). Cross-sectional images of the pulmonary artery wall demonstrated a single ring with high echodensity with a thin inner layer regarded as intima in group 1. In contrast, the majority of patients (n = 35/39) in group 2 demonstrated a thickening of the intimal layer and/or a disturbance of layering of the echogenic arterial wall. The relative wall thickness was higher in group 2 than in group 1 (22.5 +/- 10.4% vs 15.3 +/- 6.5%; P < 0.05). There were no significant correlations between pulmonary artery pressure and wall thickness pulmonary artery pressure and area change in the cardiac cycle, acetylcholine-dependent increase in pulmonary flow and morphological changes in the vessel wall. CONCLUSION: We conclude that intravascular ultrasound is capable of detecting morphological changes in the pulmonary vessel wall in pulmonary hypertension and that vessel wall hypertrophy of small pulmonary segment arteries, as detected by intravascular ultrasound, is not predictive of functional vasodilatory response of resistance vessels of the same vessel area.     

Measurement of collateral circulation blood flow in anesthetized portal hypertensive rats

AIMS: The aim of this study was to develop a technique to measure collateral blood flow in portal hypertensive rats. METHODS: Morphological techniques included inspection, casts and angiographies of portosystemic shunts. The main hemodynamic measurements were splenorenal shunt blood flow (transit time ultrasound method), percentage of portosystemic shunts and regional blood flows (microsphere method). In study 1, a model of esophageal varices was developed by ligating the splenorenal shunt. In study 2, morphological studies of the splenorenal shunt were performed in rats with portal vein ligation. In study 3, the relationship between splenorenal shunt blood flow with percentage of portosystemic shunts was evaluated in dimethylnitrosamine cirrhosis. In study 4, secondary biliary, CCl4 and dimethylnitrosamine cirrhosis were compared. In study 5, rats with portal vein ligation received acute administration of octreotide. In study 6, rats with dimethylnitrosamine cirrhosis received acute administration of vapreotide. RESULTS: Blood flow of para-esophageal varices could not be measured. SRS blood flow was correlated with the mesenteric percentage of portosystemic shunts (r = 0.74, P < 0.05), splenic percentage of portosystemic shunts (r = 0.54, P < 0.05) and estimated portosystemic blood flow (r = 0.91, P < 0.01). Splenorenal shunt blood flow was 6 to 12 times higher in portal hypertensive rats, e.g., in portal vein ligated rats: 2.8 +/- 2.7 vs 0.3 +/- 0.1 mL.min-1 in sham rats (P < 0.01), and was similar in the different cirrhosis models but was higher in portal vein ligated rats than in cirrhotic rats (1.2 +/- 0.7 vs 0.6 +/- 0.6 mL.min-1.100 g-1, P = 0.05). Octreotide significantly decreased splenorenal shunt blood flow: -23 +/- 20% (P < 0.01) vs -6 +/- 8% (not significant) in placebo rats. The variation of splenorenal shunt blood flow after vapreotide was significant but not that of the splenic percentage of portosystemic shunts compared to placebo. CONCLUSIONS: The splenorenal shunt is the main portosystemic shunt in rats. The measurement of splenorenal shunt blood flow is easy, accurate and reproducible and should replace the traditional measurement of the percentage of portosystemic shunts in pharmacological studies.     

Unexpected death of psychiatric patients: suicide, misadventure, accident or unsolved mystery?

BACKGROUND: Because of the wide range of recommended threshold values for carotid stenosis graduation we performed a prospective study to determine interobserver and interequipment variability of quantitative blood flow velocity measurements. PATIENTS AND METHODS: We recorded absolute blood flow velocities and velocity ratios in 21 patients with carotid artery stenosis using two colour coded duplex ultrasound systems an ATL Ultramark 9 HDI, and a Hewlett Packard SONOS 2500 system. The ATL system was used for the interobserver variation study, where each patient was examined twice on the same day. The Doppler angle was recorded together with blood flow velocities (peak systolic velocity and mean maximum velocity from the velocity-time-integral both in the stenosis jet and 4-5 cm distally in the cranial portion of the internal carotid artery off poststenotic turbulences). RESULTS: The ATL system generated significantly higher blood flow velocity values as compared with the HP system (218 +/- 156 cm/s vs. 169 +/- 114 cm/s; p < 0.001). The Mean Velocity Ratio (the ratio of intrastenotic Vmean and poststenotic Vmean) was constant with both duplex systems. The HP system yielded 10% (Cl, 7-13%) lower predicted stenosis estimates than the ATL system with Vmax as the stenosis criterion. The stenosis estimates calculated from Mean Velocity Ratio values did not differ significantly. The 95% Cl for predicted diameter reduction between two observer was 13.6% (Vmax) and 15.4% (Mean Velocity Ratio). CONCLUSION: Because of significant interequipment differences of colour coded duplex ultrasound systems we recommend calculation of the Mean Velocity Ratio to avoid interpatient and interequipment variation of absolute flow velocities. According to our interobserver variability study, a change of more than 15% diameter reduction on follow-up examinations indicates disease progression or regression.     

Doppler sonographic diagnosis of severe portal vein pulsatility in constrictive pericarditis: flow normalization after pericardiectomy

This case report describes the noninvasive assessment of hepatic and portal vein hemodynamics in a patient with constrictive pericarditis before and after pericardiectomy. Doppler sonography of the hepatic veins demonstrated a typical W-shaped pattern with pronounced late diastolic flow reversal that disappeared after surgery. Preoperatively, we observed severe pulsatility of the portal vein with flow reversal in systole; after pericardiectomy, portal venous flow was normal. We concluded that the high right atrial pressure in this patient might have led to increased hepatic venous outflow resistance, with subsequent trans-sinusoidal shunting between the hepatic artery and portal vein causing severe portal vein pulsatility. After pericardiectomy and a decrease in right atrial pressure, portal vein flow normalized.     

Transcranial assessment of maternal cerebral blood flow velocity in patients with pre-eclampsia

BACKGROUND: To clarify the cerebral hemodynamics in pre-eclamptic pregnant women, we investigated the blood flow velocity of the cerebral arteries. METHODS: The mean blood flow velocity and pulsatility index (PI) of the middle cerebral artery (MCA) and internal carotid artery (ICA) in normal pregnant women (n = 35) and pre-eclamptic patients (n = 18) were examined transcranially using pulsed-wave Doppler technique with a 2 MHz probe. In two pre-eclamptic women with post-partum visual disturbance, we examined the mean blood flow velocity and PI of the MCA and ICA every day. RESULTS: The mean blood flow velocity of the MCA in the pre-eclamptic patients (89.7 +/- 20.5 cm/s) was significantly higher than that in the normal pregnant women (53.6 +/- 16.9 cm/s) (p < 0.05). PI of the MCA in the former group (0.67 +/- 0.13) was significantly lower than that in the latter (0.78 +/- 0.02) (p < 0.05). There was no significant difference between these two groups in these variables of the ICA. In the two patients with visual disturbance, the mean blood flow velocity of the MCA was increased before the onset of visual disturbance and decreased gradually following the disappearance of this symptom. In these patients, spasm of the MCA was confirmed by magnetic resonance angiography. CONCLUSIONS: In pre-eclamptic patients, we found increased MCA mean velocity before the onset of visual disturbance. Transcranial Doppler may be useful for the evaluation of cerebral hemodynamics and the prediction of eclampsia.