The effect of changes in pulmonary circulation on collateral ventilation.
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Blood Circulation↗
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Exercise-induced negative U waves in precordial leads as a marker of viable myocardium in patients with recent anterior myocardial infarction.
Patients with recent anterior myocardial infarction and a significant stenosis in the left anterior descending coronary artery were divided into two groups according to the presence (Group A, n=24) or absence (Group B, n=77) of negative U waves in the precordial leads during exercise stress test to compare the coronary arteriographic findings. Both total occlusion of the left anterior descending coronary artery (79% vs. 31%, P<0.01)) and good (index=2, 3) collateral circulation to the territory of this artery (92% vs. 36%, P<0.01) were observed more often in group A than in group B. In order to determine whether detection of exercise-induced negative U waves in precordial leads can predict the presence of viable myocardium, the 56 patients (20 of group A and 36 of group B) with total or subtotal occlusion of the left anterior descending coronary artery were studied further. The coronary arteriographic and exercise 201Tl scintigraphic findings were compared between the groups. Good collateral circulation to the territory of this artery was observed significantly (P<0.05) more often in group A (100%) than in group B (61%). Patients with multivessel disease were significantly (P<0.05) more prevalent in group A (70%) than in group B (33%). The incidence of a significant partial redistribution in the anteroseptal area in the 20Tl images 4 h after exercise was significantly (P<0.01) higher in group A (85%) than in group B (39%). In 29 patients with anterior Q-wave myocardial infarction and exercise-induced ST elevation in precordial leads, a significant 201Tl redistribution in the anteroseptal area was observed in 8 (80%) of 10 patients of group A in contrast to only 4 (21%, P<0.05) of 19 in group B. In the diagnosis of the viability associated with 201Tl redistribution in the anteroseptal area by the finding of exercise-induced negative U waves, the sensitivity was 67% and the specificity was 88% in these patients. We conclude that exercise-induced negative U waves in precordial leads are a convenient and specific marker for the presence of viable myocardium in patients with recent anterior myocardial infarction.
Collateral Circulation↗
The mechanism of spinal cord injury after simple and double aortic cross-clamping.
Ischemic spinal cord injury after cross-clamping of the descending aorta can occur independently of aortic disease. In a previous study we had shown a precipitous uniform fall of spinal surface oxygen tension downstream to the clamping site irrespective of level. In the present paper, the hemodynamic changes in the spinal and aortic collateral circulation were investigated. Pressures were measured in the proximal, distal, and excluded aortic segments (descending thoracic and lumbar aorta) as well as in the intercostal and the lumbar arterial beds. Before high aortic occlusion, pressures in the intercostal and lumbar arterial beds were lower than aortic pressure. Along with the postclamping fall in distal arterial pressure, intercostal and lumbar arterial bed pressure decreased further but remained above aortic pressure. Exclusion of the thoracic aorta by double clamping restored intercostal bed pressure almost to control, whereas exclusion of the abdominal aorta hardly affected lumbar bed pressure. We conclude that spinal collateral circulation is more highly developed in the thoracic than in the lumbar region. After aortic cross-clamping, blood tends to drain away from the spinal cord rather than supplying it longitudinally. Under clinical conditions, therefore, retrograde bleeding into the opened aorta as well as into the aorta downstream to the distal clamp should be minimized and larger vessels originating from the aorta should promptly be anastomosed to the graft.
Animals↗
Assessment of the cortical rim sign in posttraumatic renal infarction.
PURPOSE: The cortical rim sign has frequently been described as a sign of renal infarction. It is reported to be present in approximately 50% of focal or global infarcts and is thought to be due to an intact renal collateral circulation. This study evaluates the incidence and temporal development of the cortical rim sign in posttraumatic renal vascular compromise. METHOD: This retrospective study included 20 patients who were diagnosed by contrast-enhanced CT to have posttraumatic focal or global infarcts. The CT scans were reviewed to evaluate the size of infarcts and the presence and appearance of the rim sign. Medical records were reviewed to identify the timing of trauma in relation to the CT examination. RESULTS: Eight patients had multiple CT examinations and 12 had a single CT study. For all cases that demonstrated a rim sign (n = 14, 8 of which had more than one CT), the earliest appearance of the rim sing was 8 h (median time to appearance was 7 days). All cases with no rim sign (n = 6) were evaluated within 10 h of trauma, with a median time of 4 h. CONCLUSION: This study suggests that in spite of the presence of renal collateral circulation, it takes a minimum period of 8 h after trauma for this circulation to expand and become apparent on CT. CT demonstrated a rim sign in all cases performed after 1 week.
Adolescent↗
Encephalo-duro-arterio-synangiosis in children with moyamoya disease.
Encephalo-duro-arterio-synangiosis (EDAS) was done in 16 Japanese children with Moyamoya disease on 22 sides. The results were evaluated clinically, angiographically, and by positron emission computed tomography (PET). Postoperative external carotid angiograms showed a good collateral circulation through EDAS in 72 percent of the treated sides. Two-thirds of the sides examined by PET showed improvement in cerebral blood circulation, particularly at the surgically-treated cortex. Postoperatively the symptoms disappeared in those with good new collateral formation. TIA, RIND, and/or involuntary movement disappeared in 31 percent and partially so in 44 percent 6 months after EDAS. The TIA in the lower limb and/or involuntary movement persisted in some children. This surgical approach seems applicable particularly for children with the ischaemic type of Moyamoya disease, however, the procedure also has drawbacks. Development of collateral circulation was insufficient in some cases, and the territories of the anterior cerebral artery (ACA) or posterior cerebral artery (PCA) were often not covered, even in those with a good new collateral formation in the middle cerebral arterial (MCA) area.
Cerebral Angiography↗
Progressive hepatocytic fatty infiltration in rats with prehepatic portal hypertension.
BACKGROUND/AIMS: Homogenous evolution, with a narrow range of portal hypertension, degree of portosystemic shunt and hepatic atrophy has been described in the experimental model of prehepatic portal hypertension in the rat. However the great differences observed in the rats' liver weight could be attributed to a pathological alteration of the liver. Based on this, we performed an evolutive histological study of the liver. This study shows the existence of a progressive hepatocytic fatty infiltration. METHODOLOGY: Male Wistar rats with portal hypertension induced by triple stenosing ligation of the portal vein at 1 month (group II, n=4) and at 1 year (group IV, n=10) of postoperative evolution were used. The portal pressure, body, liver and splenic weights, types of collateral circulation and degree of mesenteric venous congestion were studied. The intracytoplasmatic lipid microvacuoles were quantified in hepatocytes with an image analyzer (software MIP/CID, Spain). The results were compared with those obtained in control rats with the same evolutive periods (Groups I and III). RESULTS: The hepatic fatty infiltration in Group II (TPVS 1 month) (30.12+/-53.92 micron2) is similar to that presented by Group III (Control 1 year) (16.52+/-45.20 micron2), while there is an increase (p<0.001) in Group IV (triple portal vein stenosis 1 year) (182.03+/-371.42 micron2) in relation to the other groups studied. The progressive hepatic fatty infiltration in triple portal vein stenosis rats is associated with a decrease of portal pressure and of the incidence of liver hepatic atrophy, portosystemic collateral circulation and mesenteric venous congestion. CONCLUSIONS: TPVS produces progressive hepatocytic fatty infiltration in the rat so that this prehepatic portal hypertension experimental model could also be considered as a hepatic steatosis model.
Animals↗
Heparin exercise treatment following percutaneous transluminal coronary angioplasty in a patient with effort angina.
A 63-year-old female with chronic stable effort angina underwent percutaneous transluminal coronary angioplasty (PTCA) for a donating coronary artery of the collateral circulation to the jeopardized region. Because of the inefficacy of the procedure in increasing the collateral flow reserve, the patient was then put on an exercise regimen and also received heparin pretreatment. Her exercise tolerance improved remarkably with the development of improved collateral circulation.
Angina Pectoris↗
[Coronarographic and ventriculographic aspects of 76 cases of unstable angina (authors transl)].
-- Coronarographic and ventriculographic aspects of 76 patients with unstable angina were analyzed. 8 cases (10%) had normal coronary arteries, 9 (11.8%) had slight stenotic lesions (less than 50%), 59 (77.6%) had serious stenosis. The stenosis concerned only one principal branch in 22 patients (37.2%), 2 branches in 24 (40%), 3 branches in 13 (22%). In 77-79% of cases, ventricular contractility was normal. A collateral circulation was found in 58% of cases, but no link was discovered between the coronaric lesions and the clinical type of angina. The course of the illness was studied during the hospitalization and post-hospitalization period for an average observation time of 14 months (55 cases). The course of illness type depends on the number of affected branches and the myocardial contractility. In 25% of the patients with lesions in 3 branches there was an unfavourable course of illness (either infarction or death), whilst where there were lesions in one or two branches, negative results were 11% and 15% respectively. Patients with normal coronary arteries or slight stenosis had no unfavourable course of illness. In 37% of patients with altered contractility, an unfavourable course of illness was found, as against 27% with normal contractility. The presence of collateral circulation doesn't seem to influence the course the illness takes. A coronarographic examination seems to be an essential elelment in deciding on the prognosis of unstable angina.
Angina Pectoris↗
Lumbar and thoracic spinal cord oxygen tension during aortic cross-clamping.
In order to investigate the changes in tissue oxygen and the efficiency of the collateral circulation in the different regions of the spinal cord (SC) during aortic occlusion, surface PO2 (sPO2) was measured on the exposed SC in the pig in the lumbar (L3-5) as well as in the thoracic (Th6-8) parts before, during and after a 45 minute occlusion. The pigs were divided into two groups: group IA: cross-clamping of the aorta immediately below the left subclavian artery; group II: occlusion of the aorta immediately above the arteria radicularis magna anterior (ARMA). In response to occlusion, the sPO2 distal to the occlusion always decreased significantly (group IA: mean lumbar sPO2 from 42.3 mm Hg to 3.2 mm Hg, mean thoracic sPO2 from 34.9 mm Hg to 3.9 mm Hg; group II: mean lumbar sPO2 from 28.0 mm Hg to 7.9 mm Hg). Mean thoracic sPO2 in group II remained constant. No statistically significant differences between the distal regions could be established. The collateral circulation in the thoracic as well as in the lumbar region was insufficient at least during occlusion.
Animals↗
[Acute insufficiency of the ophthalmic artery during occlusion of the internal carotid artery].
The authors present a case of a patients aged 41 years in whom the acute insufficiency of the ophthalmic artery was the first and single sign of an internal carotid occlusion. Doppler's pulsating focused ultrasonography showed to be an indispensable method which rendered possible a prompt diagnosis. Besides--this methods enables us to evaluate the dynamics of changes--the regeneration of the ciliary circulation with a compensatory perfusion of blood in some branches of the posterior ciliary arteries, the creation of collateral circulation from the ipsilateral external carotid artery through the ophthalmic artery with a reverse direction of perfusion in its extent and creation of a collateral circulation from the contralateral internal carotid through the anterior cerebral artery.
Acute Disease↗
[Near infrared spectrophotometric monitoring for cerebral ischemia during the occlusion of the internal carotid artery at CEA].
Near infrared spectrophotometry provides noninvasively real-time information on cerebral oxygenation and cerebral blood volume. Using this method of spectrophotometry we investigated the adequacy of collateral circulation during cross-clamping of the internal carotid artery in patients who underwent carotid endarterectomy. In 15 patients, oxy-hemoglobin, deoxyhemoglobin and total hemoglobin were monitored continuously by near infrared spectrophotometry at the ipsilateral frontal area on the operated side. Changes in these parameters following temporary cross-clamping of the internal carotid artery were evaluated. The stump pressure of the internal carotid artery was measured in every patient. Only the maximum decrease in oxy-hemoglobin during cross-clamping of the internal carotid artery correlated significantly with the stump pressure of the internal carotid artery. Changes in oxy-hemoglobin during cross-clamping of the internal carotid artery demonstrated three patterns; no change or minimally decreased (4 patients), decrease with recovery (4 patients), and decrease without recovery (7 patients). The stump pressure of the internal carotid artery in patients who had no recovery of their decreased oxy-Hb was significantly lower than that in any other pattern (p < 0.01, Mann-Whitney U analysis). Patients who experience decrease in oxy-Hb without recovery following cross-clamping of their internal carotid artery may have poor collateral circulation and therefore may develop cerebral ischemia.
Aged↗
[Evaluation of the complications of different types of right ventricular bypass by contrast echocardiography].
We evaluated 54 patients with different right heart by-pass by means of contrast echocardiography with rapid venous injection of shaken saline (3 cc, < 20 k; 6cc, > 20 k), in order to detect venous collateral circulation in partial by-pass, pulmonary arteriovenous fistulae in partial and total by-pass, and right-to-left shunt in total by-pass. Forty three patients had partial by-pass: 29 had a bidirectional cavopulmonary anastomosis with additional pulmonary flow (systemic-pulmonary anastomosis and/or restrictive anterograde ventricular flow); 10 had a partial ventricular correction (bidirectional cavopulmonary anastomosis and non restrictive anterograde ventricular flow; two had classical Glenn procedures; two had Kawashima operations (bidirectional cavopulmonary anastomosis and non restrictive anterograde ventricular flow; two had classical Glenn procedures; two had kawashima operations (bidirectional cavopulmonary anastomosis with inferior vena cava interruption), and 11 with total by-pass (10 atriopulmonary anastomosis and 1 with total cavopulmonary anastomosis). The age ranged from 2.5 to 33 years (x = 12.2 years), and the mean postoperative period was 4.3 years. Venous collateral circulation: 32/43 patients (74%) with partial by-pass, specially in those without partial biventricular correction: 29/33 patients (88%) compared to those with partial biventricular correction: 3/10 (30%) p < 0.01. Pulmonary arteriovenous fistulae: 6/43 patients (14%) with partial by-pass; 6/33 (18%) with partial biventricular correction, 0/10 patients with partial biventricular correction, and 0/11 with total by-pass. Right-to-left shunt: 2/11 patients (18%) with total by-pass, all of them with atriopulmonary anastomosis. Contrast echocardiography is an excellent noninvasive method for the initial evaluation of specific dysfunctions of different right heart by-pass. We emphasize the higher frequency of collateral venous circulation in cavopulmonary anastomosis, that would explain the dysfunction with progressive hypoxia in the evolution of these patients. Pulmonary arteriovenous fistulae were detected only in partial by-pass, without partial biventricular correction (p < 0.01). The minor frequency of these fistulae in bidirectional cavopulmonary anastomosis would be due to additional pulmonary flow.
Adolescent↗
Stump pressure as a guide to the safety of permanent occlusion of the internal carotid artery.
Does the absolute value of the stump pressure (post-occlusion back pressure) become a useful index of a good collateral circulation? The authors continuously monitored the mean arterial pressure before, during and after 20-minute balloon test occlusion in 24 patients. The stump pressure was then compared with the results of 99mTc-hexa-methyl propyleneamine (99mTc-HMPAO) single photon emission computed tomography (SPECT) performed after 20 minutes of test occlusion. Patients who failed to tolerate even brief periods of carotid occlusion and showed asymmetric decreases in cerebral blood flow (CBF) on SPECT were divided into high and moderate risk groups. Those with no significant change in CBF on the occluded side formed the minimum risk group. Mean stump pressure was over 50 mmHg in three of a total of 13 patients in the high and moderate risk groups, and below 50 mmHg in two of the 11 patients in the minimum risk group. The ratios of the initial mean stump pressure to the pre-occlusion mean arterial pressure (%) and of the final mean stump pressure at the end of occlusion to the post-opening mean arterial pressure (%) did not exceed 58% in any patient in the high and moderate risk groups, and were at least 60% in all patients of the minimum risk group. Maintenance of a mean stump pressure of 60% or more of the mean systemic pressure during test occlusion may be a more useful index of a good collateral circulation than the absolute value of mean stump pressure.
Adult↗
Quantitative analysis of contraction band and coagulation necrosis after ischemia and reperfusion in the porcine heart.
To assess the importance of contraction band necrosis (CBN) in reperfusion, CBN, coagulation necrosis (CN), and infarct size, expressed as CBN + CN, were quantitatively analyzed in 25 porcine hearts without collateral circulation. The left anterior descending coronary artery was ligated for 20, 30, 60, and 120 min and then reperfused for 8 hr (groups 1 to 4, respectively). Five hearts were not reperfused (group 5). The areas of CBN and CN were traced at a magnification of X 100 under an inverted microscope and quantified with use of an image analyzer. There was no change in hemodynamics with either occlusion or reperfusion. Regional myocardial blood flow, measured by the generated hydrogen gas clearance method, decreased to almost zero after occlusion but recovered during reperfusion. Percent of risk area infarcted in groups 1 to 4 was 0 +/- 0%, 11 +/- 7%, 80 +/- 9%, and 96 +/- 2%, respectively, and the percent of risk area infarcted in group 4 was the same as that in hearts subjected to permanent occlusion (95 +/- 3%). The percent area of CBN was 100 +/- 0% in group 2, 68 +/- 11% in group 3, 2 +/- 1% in group 4, and 2 +/- 2% in group 5. In group 3, the inner third of the ischemic left ventricular wall showed CN and the middle and outer third CBN. These findings show that in pig hearts without collateral circulation, the transmural infarct, two-thirds of which is occupied by CBN, is evident even when reperfusion is achieved after 1 hr occlusion. Therefore, protection against CBN might reduce infarct size after reperfusion.
Animals↗
Transmyocardial laser revascularization combined with vascular endothelial growth factor 121 (VEGF121) gene therapy for chronic myocardial ischemia--do the effects really add up?
OBJECTIVE: Different therapy strategies for coronary disease in conventionally untreatable patients have been developed, among them transmyocardial laser revascularization (TMLR) and the application of growth factors. The objective of our study was to determine whether a combined therapy of TMLR with a vascular endothelial growth factor(121) (VEGF(121)) plasmid is able to stimulate the development of sufficient collateral circulation and hereby to preserve cardiac function. MATERIALS AND METHODS: A severe stenosis of the left anterior descending artery was created in healthy pigs. After 1 week, perfusion and regional contractility were assessed at baseline. Afterwards, the ischemic area was treated with TMLR (n=8), intramyocardial injection of naked plasmid DNA encoding VEGF(121) (n=7), or both (n=7). Control animals were left untreated (n=8). After 3 months, the animals were re-examined and underwent immunohistological analysis. RESULTS: The number of capillaries increased only after injection of VEGF(121) plasmid alone compared to untreated ischemia and to the other therapy groups, whereas the number of arterioles was higher following TMLR treatment alone or in combination with VEGF(121) than it was in the case in untreated ischemic animals. However, only combined VEGF(121)+TLMR therapy resulted in an improvement in regional myocardial blood flow in comparison with 1 week ischemia, indicating the efficient development of collateral circulation. In contrast, better regional contractility compared to the 1-week baseline, as well as restoration of the pre-ischemic values, were achieved by both VEGF(121) and combined VEGF(121)+TLMR therapies. CONCLUSIONS: This study of chronic myocardial ischemia with a porcine model indicates a synergistic action of TMLR and VEGF(121) gene therapy. Combined treatment alone achieved an increase of regional myocardial perfusion, which accompanied arteriogenesis and corresponded with the restoration of regional function.
Animals↗
Comparison of protein with DNA therapy for chronic myocardial ischemia using fibroblast growth factor-2.
OBJECTIVE: Treatment of coronary disease by growth factors has become an increasingly used strategy for otherwise untreatable patients and is subject to a number of clinical studies. The aim is to stimulate the development of a sufficient collateral circulation and hereby to rescue cardiac function. The objective of our study was to compare the effectiveness of fibroblast growth factor-2 (FGF-2) as protein and as naked plasmid DNA in a porcine model of chronic myocardial ischemia. MATERIALS AND METHODS: A severe stenosis of the left anterior descending artery (LAD) artery was created in healthy pigs. After 1 week, perfusion and regional and global contractility was assessed at baseline at rest and under stress. Afterwards, recombinant FGF-2 (n=6) or naked plasmid DNA encoding FGF-2 (n=7) was intramyocardially injected into the LAD territory. Control animals were left untreated (n=5). After 3 months, the animals were re-examined and underwent immunohistologic analysis. One animal received an Enhanced Green Fluorescent Protein plasmid. RESULTS: Plasmid-dependent protein synthesis was present in cardiomyocytes. FGF-2 protein as well as plasmid injections resulted in an increased number of capillaries and of arterioles compared with untreated ischemia. The improvement of the regional myocardial blood flow by FGF-2 plasmid therapy at rest might however indicate the effectiveness of the DNA application for the induction of a collateral circulation. A benefit from FGF-2 plasmid therapy was revealed with regard to regional contractility. Systemic hemodynamics were partially improved following plasFGF-2 treatment. CONCLUSIONS: In this porcine model of chronic myocardial ischemia, intramyocardial injection of FGF-2 plasmid was more effective than of FGF-2 protein in improving regional perfusion and contractility compared to untreated ischemia.
Animals↗
Effect of nitroglycerin on myocardial collateral conductance in awake dogs.
Conductance of the coronary collateral circulation during the course of two abrupt circumflex coronary occlusions (pre- and posttreatment with nitroglycerin) was measured in awake dogs approximately 2 wk after collateral vessels were stimulated to develop. The pressure gradient from the central aorta to the distal circumflex coronary artery was measured, and myocardial blood flow was determined by 9-microns radioactive microspheres at 30 s and 4 min after coronary occlusions. Collateral conductance was calculated as mean collateral blood flow divided by the mean aorta-coronary pressure gradient. Before nitroglycerin, collateral conductance increased in all eight dogs from 30 s to 4 min by a mean value of 0.006 +/- 0.003 ml.min-1.g-1.mmHg-1. After nitroglycerin administration, the conductance at 30 s increased from the prenitroglycerin control value of 0.009 +/- 0.008 to 0.014 +/- 0.012 ml.min-1.g-1.mmHg-1, P less than 0.03. The mean change in conductance from 30 s to 4 min postnitroglycerin 0.003 +/- 0.003 ml.min-1.g-1.mmHg-1 was significantly less than during prenitroglycerin (P = 0.01). These data indicate that an increase in conductance during coronary occlusion occurs even in the immature collateral circulation. This effect presumably takes place in the arterial smooth muscle at the origin of the collateral vasculature.
Animals↗
Leiomyoma of a digital artery.
Benign, soft-tissue masses of the hand are common. A vascular leiomyoma is an unusual tumor of smooth-muscle origin. In a 62-year-old man, the tumor arose from within a digital artery. Persistent symptoms prompted an excisional biopsy, requiring resection of a portion of the artery. Adequate collateral circulation preempted the need for a vascular graft. Vascular repair or grafting may be necessary if collateral circulation is not adequate.
Arteries↗