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Results for “Collateral Circulation”

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PubMedDate not supplied

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.

Animals↗

PubMed1991

Effect of propranolol on portosystemic collateral circulation in patients with cirrhosis.

Propranolol has been demonstrated to be effective in lowering portal pressure in cirrhotic patients. This effect is mediated by a reduction of splanchnic arterial inflow and a consequent decrease of portal vein and portocollateral blood flow. Although experimental studies suggest a direct effect of the drug on portocollateral circulation, little information exists about relative flow changes occurring in the portal vein and in collateral veins feeding esophageal varices. This study addressed the problem in 12 cirrhotic patients selected on the basis of feasibility of Doppler flowmetry in both the portal and left gastric veins. Caliber, flow velocity and flow volume in both vessels were measured by Doppler ultrasound before and at 60, 120 and 180 min after an oral dose of 40 mg propranolol, together with heart rate and mean arterial pressure. A significant decrease in heart rate (-17.6% +/- 1.1%, p less than 0.001) and mean arterial pressure (-10.6% +/- 0.9%, p less than 0.005) confirmed effective beta-blockade. Baseline flow velocity was significantly lower in the portal vein than in the left gastric vein (12.4 +/- 0.6 vs. 15.4 +/- 1.5 cm/sec, p less than 0.05). Maximal hemodynamic effect was reached at 120 min after administration of propranolol. The vessel caliber did not change significantly. Flow velocity fell from 12.4 +/- 0.6 to 10.4 +/- 0.7 cm/sec in the portal vein (p less than 0.05) and from 15.4 +/- 1.5 to 11.1 +/- 0.9 cm/sec in the left gastric vein (p less than 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMed1994

Coronary collateral circulation and diastolic function.

Patients with coronary artery disease reportedly have an impaired left ventricular filling. To evaluate the effects of coronary collaterals on diastolic function in patients with effort-induced angina, resting radionuclide ventriculography was performed in 14 patients with severe isolated (> or = 90% diameter) stenosis of the left anterior descending coronary artery and in seven normal subjects. Contrast ventriculography showed normal wall motion in all patients. Functional indices obtained by radionuclide ventriculography were compared between those patients with collateral vessels, Rentrop classification grades 1 (n = 7) and 3 (n = 1), and those patients without (n = 6) collateral vessels. Global peak filling rate was significantly (P < 0.01) reduced in the patients with collaterals. The septal, apical and lateral peak filling rates were also reduced in patients with collateral vessels, with the reduction in lateral peak filling rate being statistically significant (P < 0.05). The indices of systolic function and the temporal diastolic asynchronous index were similar, irrespective of the presence of collaterals. The exercise tolerance as evaluated by the rate-pressure product at peak treadmill exercise stress testing in 12 patients was significantly (P < 0.01) lower in those with collateral vessels. Angiographically visible collaterals could be a marker for more severe coronary stenosis in patients with effort-induced angina, and an indicator of the severity of deterioration in left ventricular diastolic function.

Aged↗

PubMed2000

Spleno-renal shunt blood flow is an accurate index of collateral circulation in different models of portal hypertension and after pharmacological changes in rats.

BACKGROUND/AIMS: Recently, we developed a new method to measure collateral blood flow in rats: splenorenal shunt (SRS) blood flow (BF). The aims were to evaluate the reproducibility of SRSBF measurement in different models of portal hypertension, and to investigate the ability of SRSBF to disclose pharmacological changes. METHODS: Hemodynamics were determined in anesthetized rats with secondary biliary, CCl4 or DMNA cirrhosis and portal vein ligation (PVL) under baseline and pharmacological (octreotide, vapreotide) conditions. The main measurements performed were: SRSBF by the transit time ultrasound (TTU) method and % portosystemic shunts (PSS) by the microsphere method. RESULTS: SRSBF was 6 to 10 times higher in portal hypertensive rats and was similar in the different models of cirrhosis but was higher in portal vein ligated rats than in cirrhotic rats (1.1+/-0.7 vs 0.6+/-0.7 ml x min(-1) x 100 g(-1), p=0.01). SRSBF was correlated with mesenteric %PSS (r=0.61, p<0.01), splenic %PSS (r=0.54, p<0.05), portal pressure (r= 0.32, p<0.05) and the area of liver fibrosis (r=0.33, p<0.05). Octreotide significantly decreased SRSBF (-23+/-20%, p<0.01 vs placebo: -6+/-8%, NS). Vapreotide significantly decreased SRSBF but not mesenteric or splenic %PSS compared to placebo. The variations in SRSBF (-26+/-32%) and in splenic %PSS (0+/-15%) with vapreotide were significantly different (p<0.05) and not correlated (r=-0.1, NS). CONCLUSIONS: Determination of SRSBF by TTU is an accurate way to measure collateral blood flow in different models of intra- and extra-hepatic portal hypertension in rats. Its sensitivity provides accurate measurement of pharmacological changes, unlike the traditional estimation of %PSS by the microsphere method.

Animals↗

PubMed1978

Amputation after development of collateral circulation. An arteriographic study in rabbits.

The vascular changes in the amputation stump after amputation on an extremity which is vascularized by collaterals were studied by arteriography in adult rabbits. Amputation on the crus immediately after ligature of the femoral artery caused a retardation in the development of collaterals and a protracted vasoconstriction in the amputation stump. Osseous plugging of the medullary cavity in the amputation stump counteracted the vasoconstriction, and the development of collaterals was improved. When amputation on the crus was performed 3-6 days after ligature of the femoral artery, immediate function of the collaterals and a rapid dilatation of the arteries in the below knee amputation stump were seen, and 3--4 weeks postoperatively arteriovenous shunts developed in the stump. Amputation 7--10 weeks after ligature of the artery involved a more pronounced shunt development in the amputation stump. After amputation on the femur only slight differences were observed in the development of collaterals and the vascularization in the amputation stump compared with findings after amputation on the crus.

Amputation, Surgical↗

PubMed1963