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PubMed2006

Angiotensin II type 1 receptor blockers do not promote coronary collateral circulation in patients with coronary artery disease.

We previously reported that angiotensin-converting enzyme inhibitors (ACE-Is) promote collateral circulation in patients with coronary artery disease (CAD). There have been many reports on the beneficial effects of angiotensin II type 1 receptor blockers (ARBs) on the cardiac microvasculature. Therefore, the following studies were performed to evaluate the association between treatment with an ARB and the enhancement of coronary collateral circulation as assessed by the Rentrop Score (RS) (Study 1) and to compare these results to those obtained with an ACE-I (Study 2). The subjects were 456 patients with angina who underwent coronary angiography. Study 1: Those who had one (1-V), two (2-V) or three significantly stenosed vessels (3-V) and who received only an ARB without any other anti-hypertensive medication were defined as the ARB group (n=81), and age-, sex- and body mass index-matched subjects (n=146) were selected as a comparative group. There were no significant differences in the percentage of patients with RS>or=1 between the two groups. Study 2: Those who received an ACE-I as the only anti-hypertensive treatment were defined as the ACE-I group (n=67), which was matched to the ARB group in Study 1. The percentage of patients with RS>or=1 in the ACE-I group was significantly higher than that in the ARB group as assessed by a Cochran-Mantel-Haenszel analysis. In addition, patients with 3-V disease who were treated with an ACE-I, but not an ARB, were most likely (odds ratio [confidence Interval]): 27.7 [4.8-161.0]) to show enhanced collateral circulation, as assessed by a multiple logistic regression analysis. These results suggest that treatment with an ACE-I, but not treatment with an ARB, was associated with the enhancement of collateral circulation in patients with CAD.

Aged↗

PubMedDate not supplied

Effect of collateral circulation on healing of small intestinal anastomosis in rabbits.

BACKGROUND/AIMS: In patients who have acute superior mesenteric artery occlusion and clearly gangrenous intestines, resection and anastomosis have been advised as the only surgical procedure. Distal and proximal bowel segments adjacent to this necrotic part have collateral blood supply although they have normal macroscopic appearance. After resection of necrotic segment, there will be a low flow at the anastomosis due to collateral circulation and the healing may therefore be impaired. METHODOLOGY: This situation was investigated in rabbits creating unilateral collateral circulation at the small bowel anastomosis. Bursting pressure, tissue hydroxyproline concentration and bursting sites were determined on days 4, 8, and 12. Findings were compared with the those of normal anastomosis. RESULTS: There was significantly decreased mean bursting pressure(106 +/- 40.3 mmHg) in unilateral collateral circulation group as compared with the that of control group (158 +/- 26.6 mmHg) on day 8 (p < 0.05). On the same day mean hydroxyproline concentration of this group was also lower(7.06 +/- 0.5 mg/g tissue) than the value of control group(7.69 +/- 0.4 mg/g tissue), with the statistical significance on the border line(p = 0.05). The low values of these two parameters reached normal levels on day 12. Bursting sites were mostly on the anastomotic line in unilateral collateral circulation group, while they were mostly on the bowel wall in the control group on day 8. CONCLUSION: These findings suggest an insufficient healing process in the bowel anastomosis with unilateral collateral circulation on day 8 in rabbits.

Anastomosis, Surgical↗

PubMedDate not supplied

Persistence of collateral circulation after correction of aortic coarctation.

The persistence of collateral circulation was evaluated one year after the correction of experimental aortic coarctation (CoA) by assessing renal perfusion with the Xenon 133-washout method and measuring distal aortic blood pressure during cross-clamping of the thoracic aorta. CoA was created in 7 puppies at 2 months of age and was corrected after a follow-up with a venous patch when the dogs were 9 months old. Two of the dogs were lost during the corrective operation due to anaesthetic complications. Four sham-operated dogs served as controls. One year after correction of CoA, four of the dogs had a pressure gradient of less than 5 mmHg at the site of CoA and one a pressure gradient of 15 mmHg. In renal perfusion measurements a mean decrease of 49% and 96% was found in the study and control groups, respectively. Blood pressures in the distal aorta decreased 47% and 83%, respectively. Two dogs in the study group had a distal blood pressure under 50 mmHg and their renal perfusion decreased markedly. Collateral circulation decreased with time after a good anatomic correction of CoA, so that one year after correction of experimental CoA about one half of the initial collateral capacity remained. This suggests that in most reoperations performed at least one year after the primary corrections, temporal shunting or a left side bypass is necessary to ensure sufficient circulation in the distal organs.

Animals↗

PubMed1994

Importance of the coronary collateral circulation for the distribution of anterograde and retrograde delivered cardioplegic solution in aortocoronary bypass surgery: a haemodynamic study.

The importance of coronary collateral circulation for homogeneous distribution of anterograde and retrograde delivery of cardioplegia was evaluated in 36 patients undergoing myocardial revascularization. All patients had three-vessel coronary artery disease, with a stenosis of the right coronary artery of at least 80%. The patients were randomized into two groups: group A (n = 19) received anterograde delivered cardioplegic solution and group B (n = 17) received retrograde. Both groups were further subdivided depending on the pathology of the right coronary artery, as evaluated on preoperative coronary angiography. In group A1 (n = 8) and group B1 (n = 7) there was no visualization of collateral circulation from the left to the right coronary artery system, whereas in group A2 (n = 11) and group B2 (n = 10) there was retrograde filling of the right coronary artery by collateral circulation. Right atrial pressure increased significantly (P < 0.05) in group A1 and was elevated in group A2, but not significantly (P = 0.07). By contrast, right arterial pressure decreased in groups B1 and B2. Analysis of the individual differences in the right atrial filling pressure showed a statistical significance between the two subgroups (group B1-1.0(0.5) versus group B2-1.8(1.1), P < 0.05), although the individual decrease of the right ventricular stroke work index was not significant. It is concluded that collateral circulation is important for an adequate distribution of anterogradely delivered cardioplegia and is also beneficial in cases of retrograde delivery.

Adult↗

PubMed2007

Importance of collateral circulation in coronary heart disease.

AIMS: Collateral arteries are a common but inconsistent finding in coronary heart disease (CHD). We endeavoured to review the methods for coronary artery collateral assessment, the predictors and clinical importance of collateral blood flow, and the potential for therapeutic augmentation of collateral anastomoses. METHODS AND RESULTS: While many methods have been used to assess collateral blood flow only a few have been formally validated. Collateral flow index, as determined by measurement of intra-coronary pressure or flow velocity, is the most robust measure of collateral flow. These techniques have led to important advances in our understanding of collateral artery function. Coronary collateral arteries may prevent myocardial ischaemia in healthy subjects and in patients with CHD. A functional collateral circulation may lead to reduced ischaemia, preservation of ventricular function, and an improved prognosis. Recent trials have demonstrated that vascular progenitor cell therapies may improve ventricular function following acute myocardial infarction, raising the possibility of effective biological treatments to improve myocardial blood flow and prognosis in CHD. CONCLUSIONS: Coronary collateral anastomoses represent a prognostically important adaptive response in patients with CHD. Therapeutic augmentation of collaterals with emerging biological therapies represents a desirable goal for treating CHD patients.

Collateral Circulation↗

PubMed1994

Variable responses of highly stenotic coronary arteries and collateral circulation to intracoronary injection of nitroglycerin in patients with chronic effort angina.

AIM: To assess the direct effects of nitroglycerin on coronary and collateral circulation, 31 consecutive patients with low exercise capacity resulting from chronic effort angina but who had not suffered previous myocardial infarction were investigated. METHODS: Rapid atrial pacing was used to induce myocardial ischemia, with the same pacing rate before and after an intracoronary injection of 50 micrograms nitroglycerin. Fifteen patients (group A) with an obstructed ischemia-related coronary artery (IRCA) (TIMI flow grade 0 or 1), were injected with nitroglycerin into a major donor artery of the well-developed collateral circulation. Sixteen patients with patent IRCAs (TIMI flow grade 2 or 3) were injected with nitroglycerin into the IRCA. These patients were subdivided according to the morphologic findings of the stenosis in the IRCA: group B, nine patients with eccentric elliptical residual lumens, and group C, seven patients with circular residual lumens. RESULTS: In group A, 0.21 +/- 0.08 mV of pacing-induced ST-segment depression was consistently ameliorated to 0.08 +/- 0.05 mV after pretreatment with nitroglycerin (P < 0.0001). In group B, the extent of ST-segment depression was markedly improved from a basal value of 0.21 +/- 0.05 mV to 0.05 +/- 0.03 mV with nitroglycerin (P < 0.001). In contrast, in group C ST-segment depression remained unchanged despite pretreatment with nitroglycerin (0.21 +/- 0.04 mV to 0.21 +/- 0.05 mV, P = NS). CONCLUSION: These results indicate that the contribution of the dynamic stenosis of the IRCA to effort angina differs greatly among patients and depends on the morphologic findings of the stenosis in the IRCA, and also that collateral circulation responds effectively to intracoronary injection of nitroglycerin in all patients with a well-developed collateral circulation.

Adult↗

PubMed1987

Vasomotor properties of immature canine coronary collateral circulation.

This study examined the ability of the immature coronary collateral circulation to undergo vasodilation in response to nitroglycerin and vasoconstriction in response to alpha-adrenoceptor stimulation. Studies were performed in 12 anesthetized dogs. Collateral flow was estimated from measurements of retrograde flow from the acutely ligated and cannulated anterior descending branch of the left coronary artery. Antegrade flow into the collateral-dependent myocardium was minimized by embolizing the anterior descending artery with 25-microns microspheres. Drugs to be tested were introduced into the left main coronary artery to reach collateral vessels arising from the left circumflex and septal arteries. Intracoronary administration of nitroglycerin (6 micrograms X kg-1 X min-1) resulted in a 33 +/- 7.7% increase in retrograde blood flow (P less than 0.01) and a 23 +/- 3.8% decrease in calculated collateral resistance (P less than 0.01). No significant change occurred in retrograde blood flow or calculated collateral resistance during cardiac sympathetic nerve stimulation after beta-adrenergic blockade with propranolol, selective alpha-adrenergic stimulation with phenylephrine (1 microgram X kg-1 X min-1), or selective alpha 2-stimulation with BHT 933 (2 micrograms X kg-1 X min-1). Thus, the immature coronary collateral circulation was capable of active vasomotion, as demonstrated by vasodilation in response to nitroglycerin, but did not undergo vasoconstriction in response to alpha-adrenoceptor stimulation.

Animals↗

PubMed2003

[Portal collateral circulation and pancreatic carcinoma: bypass the obstacle].

Portal thrombosis with collateral circulation complicating carcinoma of the head of the pancreas is a contraindication for surgical management of this type of neoplasm. We report a case of a female patient whose portal collateral circulation was first treated by an endoportal transhepatic prosthesis. Three months later, curative surgical resection of pancreatic adenocarcinoma was performed. This case illustrates an interesting two-phase surgical management of pancreatic adenocarcinoma with portal thrombosis, possible when there is not other surgical contraindication.

Adenocarcinoma↗

PubMed2006

Rapid decline of collateral circulation increases susceptibility to myocardial ischemia: the trade-off of successful percutaneous recanalization of chronic total occlusions.

OBJECTIVES: We evaluated the time-behavior of changes in collateral circulation after successful percutaneous coronary intervention (PCI) with drug-eluting stents (DES) in chronic (>1 month) total occlusions (CTO), and assessed their relationship with myocardial ischemia. BACKGROUND: It has been hypothesized that the immediate reduction of collateral flow after PCI of CTO could expose the patients to a higher risk of future ischemic events in the case of vessel reocclusion. METHODS: In 42 patients with CTO, two consecutive balloon inflations and final DES deployment were performed after positioning of a pressure guidewire. Minimal lumen diameter (MLD), diameter stenosis (DS), angiographic collateral grading (Rentrop score), myocardial (FFRmyo), coronary (FFRcor), and collateral fractional flow reserve (FFRcoll) were evaluated. Chest pain and the sum of ST-segment elevation (SigmaST) were analyzed to document the occurrence and extent of myocardial ischemia. RESULTS: Percutaneous coronary intervention induced a progressive improvement of indexes of stenosis severity (MLD, DS, Thrombolysis in Myocardial Infarction flow, FFRmyo, and FFRcor) and a rapid reduction in collateral circulation (FFRcoll and Rentrop score). A progressive worsening of ischemia at each balloon inflation occurred, concomitant with the reduction of collateral circulation. At linear regression analysis, an inverse relationship of FFRcoll with SigmaST (R2 = 0.352, p < 0.001) and angina pain score (R(2) = 0.247, p < 0.001) was observed. CONCLUSIONS: In CTO, collateral circulation, which provides most coronary flow at baseline, rapidly declines after successful stent implantation and the restoration of an antegrade flow. This rapid de-recruitment of collaterals is likely to put such patients at risk of future ischemic events.

Aged↗

PubMed2002

[Prevalence and significance of coronary collateral circulation in patients with acute myocardial infarct].

UNLABELLED: Angiograms from consecutive and unselected patients with acute myocardial infarction were studied with respect to the prevalence as well as the significance of coronary collateral circulation to myocardium distal to the acute coronary occlusion. METHODS: Coronary angiograms were obtained from 700 consecutive and unselected patients with an acute transmural infarction within 3.7 +/- 3 hours (0.5-12) of symptom onset. No patient had undergone i.v. thrombolysis prior to angiography. Complete and acute vessel occlusion was found in 626/700 patients (89%). Coronary collaterals were detected and graded using Rentrop's classification. The grade of collateral circulation was related to the clinical course after 30 days and to the global and regional left ventricular wall motion. RESULTS: Collaterals were found in 334 patients (69%); 242 patients (38%) had collateral flow grade 2 or 3. Collaterals were demonstrated more frequently in women vs men and in patients with multivessel disease. The prevalence of collaterals was unrelated to age and the presence of diabetes mellitus. Patients who had angiography within 3 hours of symptom onset had collaterals detected less frequently than patients who had angiography beyond 6 hours (66% vs 75%, p < 0.05). No collaterals were found in 17/37 patients (47%) in cardiogenic shock and inferior MI but in only 30/164 patients (18%, p < 0.01) without shock. Global and regional left ventricular wall motion after 2 weeks was unrelated to the degree of coronary collateral circulation during acute myocardial infarction. CONCLUSION: Collateral circulation to myocardium distal to an acutely occluded coronary artery is detected in 2/3 patients during the acute infarct phase. The absence of collaterals is related to the early occurrence of cardiogenic shock in patients with inferior MI but not to the presence of diabetes mellitus. After direct angioplasty of the infarct vessel, the protective effects of coronary collaterals on chronic LV function remain uncertain.

Aged↗

PubMed1990

Heterotopic auxiliary liver transplantation with portal flow. Gradual development of the collateral circulation.

One of the causes of auxiliary liver transplantation failure is the inter-liver competition between the host liver and the graft for the hepatotrophic factors of the portal blood. We have developed an experimental model of heterotopic partial (30%) liver isotransplant using Wistar rats so as to study this competition. Splenoportography and dissection demonstrate the existence of collateral circulation. The collaterals at 90 days post-transplant (PT) consisted of veins from the portal vein to the host liver (PR), paraesophageal veins (PE) and splenorenal veins (SR). At 60 days P.T., PR and SR veins but not PE ones appeared, and at 30 days P.T., there were only PR veins. Graft atrophy at 90 days P.T. was associated with a severe degree of bile duct proliferation. The gradual development of portal hypertension causes porto-systemic collateral circulation and the graft loses the portal hepatotrophic factors. The late development of the portal hypertension and the biliary proliferation could be caused by the hepatic arterial ischemia in this experimental model. Thus, as has been described in the orthotopic liver transplantation, the heterotopic one might require a double vascularization, both portal and arterial.

Animals↗

PubMed2004

[Effect of different angiotensin converting enzyme inhibitors on coronary collateral circulation].

OBJECTIVE: To observe the effects of different angiotensin converting enzyme inhibitors (ACEI) on coronary collateral circulation. METHODS: Twenty-four healthy dogs underwent measurement of distolic aortic pressure (DAP) and ligation of the left anterior descending coronary artery. The distolic coronary pressure (DCP) and retrograde blood flow (Qret) were measured. Five days after the operation the dogs were randomly divided into three groups of 8 dogs: benazepril group (benazepril 10 mg qd); captopril group (captopril 12.5 mg bid) and control group (starch tablet was given). Thirty days after the operation a reflux catheter was inserted to measure the DCP and Qret again. Then the dogs were killed and their hearts were taken out to examine the pathologic changes. The angiotensin converting enzyme (ACE) activity levels in plasma and myocardium were examined by FAPGG spectrophotometry. RESULTS: (1) In the captopril group the plasma ACE activity was (24.1 +/- 0.6) U/L 10 days after medication, and 24.3 +/- 0.6 U/L twenty-five days after medication, both significantly lower than that before medication [(57.6 +/- 0.8) U/L, both P < 0.01]; in benazepril group the plasma ACE activity was (24.4 +/- 0.4) U/L ten days after medication, and (24.0 +/- 0.5) U/L 25 days after medication, both significantly lower than that before medication [(59.5 +/- 1.3) U/L, both P < 0.01]. The plasma ACE activity levels of captopril and benazepril groups, especially of the benazepril group, after medication were significantly lower than that of the control group. The tissue ACE activity levels of the captopril and benazepril groups were lower than that of the control group. (2) The values of DCP in the control and captopril group were higher after medication than before medication. A tendency of decrease of DCP was shown in the benazepril group, however, without statistical significance. (3) In the control group Qcol was (2.01 +/- 0.31) ml/min 25 days after medication, significantly than that before medication [(0.91 +/- 0.15) ml/min], the corresponding values in captopril group were (2.24 +/- 0.46) ml/min and (0.88 +/- 0.13) ml/min respectively in the captopril group and (3.18 +/- 0.27) ml/min and (0.89 +/- 0.11) ml/min respectively in the benazepril group with the value 25 days after in the benazepril group being the highest. (4) 30 days after operation collateral circulation was established in the ischemic myocardium in all 3 groups. The microvessel density in the ischemic zone of myocardium was higher than that in the nonischemic zone in all 3 groups. The microvessel density in the ischemic zone of myocardium was greater in the benazepril group than in the captopril and control groups. There was no difference in microvessel density between the captopril group and control group. CONCLUSION: Benazepril increases the microvessel density and collateral flow, promotes the creation of collateral circulation in ischemic area, but captopril has not such effects.

Angiotensin-Converting Enzyme Inhibitors↗

PubMed1993

Importance of ischemic preconditioning and collateral circulation for left ventricular functional recovery in patients with successful intracoronary thrombolysis for acute myocardial infarction.

We studied the effects of myocardial ischemic preconditioning and preexistent collateral circulation on the preservation of left ventricular function in 30 patients who had successful intracoronary thrombolysis within 6 hours after the onset of a first acute anterior myocardial infarction. The existence of ischemic preconditioning was defined as the episode of recurrent ischemic chest pain within 4 hours before the onset of acute myocardial infarction. In 16 patients with ischemic preconditioning (group A), the left ventricular ejection fraction during the convalescence of myocardial infarction was 57% +/- 11% (mean +/- SD); regional wall motion in the infarct area was 13% +/- 9%. In 14 patients without ischemic preconditioning (group B), the left ventricular ejection fraction and regional wall motion in the infarct area were 46% +/- 9% and 5% +/- 9% (both p < 0.05 vs group A). Moreover, among group A patients, seven patients having a well-developed collateral circulation during the acute stage of myocardial infarction showed a more prominent improvement in regional wall motion in the infarct area compared with nine patients having poor or no collateral circulation (18% +/- 8% vs 9% +/- 7%, p < 0.05). These data indicate that ischemic preconditioning is effective for the preservation of left ventricular function in patients with successful intracoronary thrombolysis and that preexistent coronary collateral circulation potentiates this favorable effect of ischemic preconditioning.

Adult↗

PubMed2001

Deformation of the bladder due to collateral circulation caused by thrombosis of the left femoral vein.

A thrombus in the lower extremities as well as in its collateral circulation in the pelvis are not unusual conditions; however, bladder deformation due to such collateral circulation has not previously been reported. A case is presented of bladder deformation to the right due to collateral circulation caused by a thrombus in the lower left extremity in a 51-year-old man.

Collateral Circulation↗

PubMed1979

Functional effect of collateral circulation after dearterialization of the liver.

The functional effect of the collateral circulation after hepatic dearterialization was investigated in dogs with end-to-side protacaval shunt after ligation of hepatic artery. The functional effect of collateral circulation was far less than that of the native hepatic artery even for one week after occlusion of the common hepatic artery. However the functional effect of the collateral blood flow suddenly rose to the level of that of native hepatic artery one week after ligation of common hepatic artery or two weeks after ligation of proper hepatic artery.

Animals↗

PubMed1984

[Relationship between myocardial contractility and collateral circulation in patients with ischemic heart disease].

By analyzing coronary angiograms and ventriculograms of 61 patients with the narrowed lumen of one or several coronary vessels by 90-100%, the dependence of the contractile function of the myocardium on the development of the collateral circulation in the cardiac muscle was studied. The assessment of the segmentary contractility of the left ventricle served as a criterion of the efficiency of the collateral circulation. The segmentary contractility was shown to be dependent on the presence or absence of the collateral circulation and also on the number of damaged vessels. The collateral circulation was also demonstrated to contribute to the maintenance of the contractile function of the myocardium.

Adult↗

PubMed1982

Acute renal artery occlusion: the role of collateral circulation.

It is not known if no when the probability of success is sufficient to warrant emergency revascularization of acute renal artery occlusion. This probability depends on the ability of collateral circulation to maintain viability. The role of collateral circulation in maintaining renal viability during six and 48 hours of renal artery occlusion has been studied in mongrel dogs. Collateral circulation is sufficient to maintain renal viability beyond the three hours of warm complete ischemia known to cause infarction. It is not sufficient to prevent progressive loss of renal function. Hypertension frequently results. Emergency revascularization of acute bilateral renal artery occlusion, therefore, is indicated. It is not indicated for unilateral occlusion with adequate contralateral function because of the high probability of resulting hypertension.

Acute Disease↗

PubMed1992

Improved myocardial ischemic response and enhanced collateral circulation with long repetitive coronary occlusion during angioplasty: a prospective study.

OBJECTIVES: The goal of the study was to evaluate the progressive increase in ischemic threshold with multiple sequential transient coronary occlusions and to assess the role of the collateral circulation in adaptation to ischemia. BACKGROUND: It has been observed that the duration of balloon inflations during coronary angioplasty can be gradually prolonged during subsequent dilations with a reduction in patient symptoms and diminished ischemic electrocardiographic (ECG) changes. Although the mechanism has not been fully explained, recruitment of coronary collateral circulation induced by repeated coronary occlusion has been reported. The stimuli for recruitment and the natural history of coronary collateral circulation are not understood. METHODS: Seventeen patients with isolated stenosis of the left anterior descending coronary artery and a normal left ventricle were enrolled. Angioplasty consisted of five successive prolonged inflations. Sequential changes in clinical, intracoronary ECG and left ventricular indexes of myocardial ischemia were examined. Coronary collateral channels were evaluated during balloon inflations by ipsilateral and contralateral injections of contrast medium and hemodynamically by occlusion pressure. RESULTS: An improved tolerance to myocardial ischemia with repetitive coronary occlusions was demonstrated by a significant reduction of angina, ST segment deviation, left ventricular filling pressure and less impairment of ejection fraction. Left ventricular wall motion abnormalities remained unchanged. Collateral angiographic grade did not change in 7 patients and increased in 10. CONCLUSIONS: This study confirms a progressive adaptation of myocardial ischemia to repetitive coronary occlusions and supports the concept that sequential episodes of myocardial ischemia are a stimulating factor for the recruitment of collateral channels in humans. These results also suggest that enhancement of recruitable collateral circulation might be an underlying mechanism of myocardial ischemic preconditioning.

Adult↗