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PubMed1987

Quantitative analysis of infarct size, contraction band necrosis, and coagulation necrosis in human autopsied hearts with acute myocardial infarction after treatment with selective intracoronary thrombolysis.

To assess the importance of contraction band necrosis (CBN) in patients with acute myocardial infarction (AMI) treated with selective intracoronary thrombolysis, CBN, coagulation necrosis, and infarct size (expressed as CBN + coagulation necrosis) were analyzed quantitatively in 16 autopsied hearts. Intracoronary thrombolysis was performed from 2 to 6 hr after the onset of AMI, and the time from the onset of AMI to death was 7 to 168 hr. Cineangiography revealed no evidence of good collateral circulation in any of the patients. The 16 patients were classified into three groups: six patients with successful thrombolysis (100% to 99% stenosis, group I), five patients with unsuccessful thrombolysis (100% to 100%, group II), and five patients with 99% stenosis before thrombolysis (group III). Among the three groups, there were no significant differences in the time from the onset of AMI to thrombolysis, the time from the onset of AMI to death, the cause of death, or the degree of collateral circulation. The percentage of the risk area involved by the infarct in group I (82 +/- 6%) was similar to that in group II (80 +/- 11%). Infarct size was not reduced in group I because collateral circulation was not good and because the degree of recanalization after thrombolysis was 1%. However, the percentage of the infarct area with CBN was significantly higher in group I (20 +/- 9%) then in group II (3 +/- 3%). This finding shows that diffuse CBN occurred after reperfusion in patients with AMI treated with thrombolysis.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗

PubMed1988

Tetralogy of Fallot with absent ductus arteriosus and absent collateral pulmonary circulation: diagnostic and surgical implications during the neonatal period.

A newborn infant with tetralogy of Fallot and presumed agenesis of the ductus arteriosus presented without the expected associated pulmonic regurgitation and aneurysmal pulmonary arteries. The presumption of agenesis of the ductus arteriosus was made because there was no reduction in cyanosis following prostaglandin E1 treatment and no remnant of ductus arteriosus could be demonstrated by angiography at 19 h of age. The fetal hemodynamics inferred in this infant are discussed with reference to the absence of aneurysmal pulmonary arteries. Closed transventricular pulmonary valvulotomy is recommended as emergency palliation for symptomatic newborns with this variant of tetralogy of Fallot because further reduction of pulmonary vascular bed, even temporarily, as in unilateral pulmonary artery cross-clamping for systemic-pulmonary anastomosis, may not be tolerated without the use of cardiopulmonary bypass.

Collateral Circulation↗

PubMed2001

Cytochrome oxidase activity in splanchnic organs of portal hypertensive rats.

OBJECTIVE: Portal hypertension is characterized by hyperdynamic splanchnic circulation associated with the development of portosystemic portal collateral circulation. Since blood flow regulation mechanisms in the splanchnic organs can be metabolic, its metabolic capacity has been studied using the mitochondrial enzyme cytochrome C oxidase as histochemical marker. METHOD: Cytochrome oxidase was quantified with a histochemical technique in the liver, pancreas and small bowel of Wistar rats in the control group (n = 8) and in rats with portal hypertension by triple stenosing ligation of the portal vein (n = 9) at 28 days of evolution. RESULTS: All rats with portal hypertension develop portosystemic collateral circulation. In these animals, cytochrome oxidase activity increases (p < 0.01) in the liver (left lateral lobe, periportal zone: 91.81 +/- 5.18 vs. 86.03 +/- 2.82) exocrine pancreas (125.6 +/- 7.25 vs 117.57 +/- 6.43; p < 0.05) as well as in the mucosa (crypts) and duodenum serosa, jejunum and ileum while it decreases in the pericentral zone of the hepatic acinus and intestinal villi. CONCLUSION: Cytochrome oxidase is considered an endogenous marker of local tissular metabolic capacity, so that its increased activity in the small bowel mucosa, crypts, exocrine pancreas and visceral peritoneum may be a metabolic factor that induces splanchnic hyperdynamic circulation in short-term portal hypertensive rats.

Animals↗

PubMed2003

Hemodynamic effects of acute and chronic administration of vapreotide in rats with cirrhosis.

The aim of this study was to assess the hemodynamic effects of acute and chronic administration of vapreotide, a somatostatin analog, in rats with intrahepatic portal hypertension induced by dimethylnitrosamine (DMNA) administration. Acute effects were evaluated at baseline and 30 min after placebo (N = 13) or vapreotide (8 /microg/kg/hr, N = 13) infusions in DMNA rats. Chronic hemodynamic effects were evaluated using subcutaneous implants for five weeks in anesthetized DMNA rats (placebo: N = 13, vapreotide: N = 13) and in sham rats (placebo: N = 10, vapreotide: N = 10). Hemodynamic measurements included splenorenal shunt blood flow (SRS BF) by the transit time ultrasound (TTU) method and cardiac output by the combined dilution-TTU method. Acute administration of vapreotide significantly decreased SRS BF (-17.3 +/- 19 vs - 1.1 +/- 14%, P < 0.05) and portal pressure (-8 +/- 9 vs 0 +/- 8%, p < 0.05) compared to placebo without systemic effects. Chronic administration of vapreotide significantly reduced the increase in SRS BF (2.4 +/- 1.5 vs 1.2 +/- 1.0 ml/min, P < 0.05) and cardiac index (50 +/- 15 vs 33 +/- 10 ml/min/100 g, P < 0.0001) while portal pressure and blood flow, and mean arterial pressure were not significantly changed compared to placebo. In conclusion, the acute administration of vapreotide decreased collateral circulation blood flow while chronic administration attenuated its development. Vapreotide seems to have a vasoconstrictive effect on collateral circulation.

Analgesics↗

PubMed1995

Morphology of cerebral arteries.

A comparison of the major cerebral arteries between humans and rats shows many similarities, including anomalies in their general organization, the structure of these vessels at the light and electron microscope levels and their morphological changes associated with cerebral vascular diseases. The general organization of the major cerebral arteries shows the following main differences between humans and rats. In rats, the internal carotid arteries have become an integral part of the circle of Willis. In the anterior cerebral arteries, a common variation in humans is the underdevelopment of one of the two arteries, whereas in rats, buttonhole-like structures are common in one or both arteries. The anterior communicating artery present in humans is absent in rats. The olfactory artery is prominent in rats, but absent in humans. The posterior communicating artery in humans is the most variable component of the circle of Willis, being asymmetric in its origin, diameters and branches. Similarly, the posterior cerebral arteries in rats often exhibit asymmetrical origin from the basilar artery. There was some confusion in the literature regarding the name of the posterior cerebral arteries in rats, but this was caused mainly by misquotations and incorrect interpretations of the papers. In humans, most aneurysms occur in the anterior half of the circle of Willis, and the incidence is higher in females than males; the middle cerebral artery is most often the one to become occluded, and the vertebral arteries are common sites for thrombosis. The various channels that constitute collateral circulation in humans provide a margin of safety, so that in case of cerebral occlusion due to thrombosis, atherosclerosis, or vasospasm related to hemorrhage, blood supply to the affected area can be maintained through these collaterals. Collateral circulation is also present in rats. However, in rats, information on the presence of various types of aneurysms, their location and frequency in normal and experimental models of hypertension and stroke is still lacking. Cerebral arteries from humans and rats are characterized by the absence of external elastic lamina, as compared with systemic arteries. A type of multipolar cell resembling the interstitial cell of Cajal is present in the cerebral arteries of humans. Its function is unknown. Earlier reports of cerebral valves have been shown to represent intimal cushions near the branching points of the cerebral arteries. Intravascular bridges present in human cerebral arteries, have not been reported in rats. Finally, the presence of vascular remodeling, as found in the cerebral arterioles of hypertensive rats, remains to be established in the cerebral arterioles of human hypertensives.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗

PubMed1999

Angiographic methods to assess human coronary angiogenesis.

It is unclear how agents designed to promote angiogenesis in the human heart affect the arteriographic appearance of the collateral circulation. Possible changes in collateral vessels include new collateral vessels arising from epicardial arteries, new branches emanating from existing collateral vessels, wider or longer collateral vessels, and higher dye transit rates that result in improved recipient vessel filling. Given the multiple mechanisms by which these new agents may improve myocardial perfusion, a rigorous, systematic, and comprehensive analysis of coronary arteriograms is required to discern the true mechanism of benefit. The method of analysis must account for potential changes in collateral blood flow, number, branching pattern, and length as well as changes in recipient vessel filling. The ability to detect differences between intricate networks of vessels in an angiographic study is dependent on maintaining consistency in cinefilming as well as the core laboratory methods between time points. In this report, we describe the methodology our angiographic core laboratory has found to be most effective to evaluate these very complex angiograms and attempt to capture all the possible modalities of angiogenesis.

Collateral Circulation↗

PubMed1988

Effects of glyceryl trinitrate on functionally regressed newly developed collateral vessels in conscious dogs.

The effects of glyceryl trinitrate on collateral blood flow and regional myocardial function during a 2 min coronary occlusion were evaluated in 10 conscious dogs with well developed collateral vessels. Collateral growth was promoted by brief, repeated, reversible coronary occlusions. After partial regression in collateral function a small dose of glyceryl trinitrate (5 micrograms.kg-1) was injected intravenously 1 min before coronary occlusion. After pretreatment with glyceryl trinitrate the collateral blood flow velocity (mean[SD]) increased from 3.0(0.9) to 4.4(1.4) cm.s-1 (p less than 0.05). After 2 min of occlusion the percentage systolic subendocardial segment shortening in the collateral dependent zone increased from 7.8(6.1) to 12.6(6.7)% (p less than 0.05). The blood flow debt repayment after release of the occlusion decreased from 122(41) to 68(34%) (p less than 0.05). Thus in conscious dogs with regressed newly developed collaterals a major component of the beneficial effects of glyceryl trinitrate on collateral circulation is dilatation of collateral vessels, as evidenced by a pronounced increase in collateral blood flow and myocardial function during a transient period of coronary occlusion.

Animals↗

PubMed1976

Panel V: Acceleration of collaterals due to physical activity--dogma or fast. A misguided goal or unrealized objective?--introduction.

The hypothesis drawn from Eckstein's study of dogs [5] suggests that collateral circulation (measured retrograde coronary collateral flow) could be enhanced in man provided that the coronary arteries were partially obstructed before training. The currently available data on the effects of exercise training on arteriosclerotic heart disease subjects with significant, but not complete, obstruction, and without collateral vessels before training, indicate that visible coronary collateral vessels do not develop unless further coronary obstruction progresses to complete or near complete occlusion. Although the above hypothesis is not supported by the angiographic studies to date, final judgment should be held in abeyance until data are presented on the collateral flow and regional myocardial perfusion in exercise-trained human subjects with arteriosclerotic heart disease.

Animals↗

PubMed1976

The assessment of function of left ventricle and patency of aorta-coronary bypass after operation. A study of systolic time intervals.

The effect of aorta-coronary bypass surgery on left ventricular function was evaluated in 39 patients by cardiac catheterization and recording of the systolic time intervals (STI) before and an average of 4.5 months following myocardial revascularization. All patients were in sinus rhythm, had normal QRS intervals on the electrocardiogram, and had taken no medication for at least 3 weeks prior to the study. The STI was unchanged postoperatively in patients with the following characteristics: freedom from angina; heart rate not more than 15 beats greater than the preoperative level; all grafts patent; and no progression of disease in coronary arteries. Deterioration in left ventricular function after operation as represented by shortened left ventricular ejection time, (LVET) prolonged pre-ejection period (PEP), and increased ratio of PEP/LVET was found in patients with the following characteristics: persistent angina; heart rate more than 14 beats faster than the preoperative level; occlusion of any grafts; progression of disease in the coronary arteries; evidence for postoperative myocardial infarction. Worsening of left ventricular performance as determined by STI was more apparent in patients with occluded grafts and no collateral circulation than in those with occluded grafts and collateral circulation which may have offered protection against ischemia. These investigations supported the use of STI in assessing changes in left ventricular function after coronary bypass and, by inference, in assessing the status of the graft.

Adult↗

PubMed1980

[Complete obstruction of the common trunk of the left coronary vessel. Observation of a case].

A case of complete left main coronary artery obstruction is described. After an anterolateral and inferior subendocardial myocardial infarction, the patient remained symptomatic and underwent an angiographic investigation. Complete left main artery obstruction was disclosed and an important coronary collateral circulation was evidenced. This collaterality explains the absence of extensive transmural myocardial infarction of some patients with left main coronary artery thrombosis.

Collateral Circulation↗

PubMed1995

[The peak of creatine phosphokinase level in the acute phase of myocardial infarction in patients with and without ischemic precedents].

Two hundred and one patients admitted to Coronary Care Unit with documented acute myocardial infarction, whose chest pain had occurred within 12 hours of hospital admission non thrombolised, were studied. The peak of creatine kinase (CK) was examined and compared between patients without previous manifestations of myocardial ischemia (group A, 106 patients) and patients with/history angina pector or healed myocardial infarction (group B, 95 patients). The mean peak creatine kinase level in the negative history group was higher (2261 +/- 226 U/L vs 1779 +/- 97 U/L p < 0.001), especially in patients aged less than 65. No significant difference was observed in patients aged more than 64 of the two groups. Patients with a positive history presented more frequently ischemic complications (p < 0.05) while the frequency of hemodynamic disturbances and arrhythmias was not significantly different. Total mortality was similar in the two groups (22.6% vs 21%) and more frequently occurred in older patients with congestive heart failure. The authors form the hypothesis that the higher mean peak creatine level in patients without previous myocardial ischemia is the result of absence of coronary collateral circulation. The presence of collateral vessels permits less extensive myocardial infarction but it does not change the prognosis.

Aged↗

PubMed1993

[Clinico-pathological study of the mechanism of initiation and progression of right ventricular infarction].

To clarify the mechanism of initiation and progression of right ventricular myocardial infarction, 35 cases were examined among 236 cases of consecutively autopsied hearts. Twenty-six (52%) of 50 cases with posterior left ventricular infarction showed right ventricular infarction, and no statistical differences were observed in the age, gender, and number of impaired vessels among patients with and without right ventricular infarction. However, more proximal occlusion or more extensive thrombi in the right coronary artery did play a very important role in the genesis of the infarction and its progression. Right ventricular dilatation was frequently associated, probably resulted from the functional disorder of contraction and relaxation of the myocardium. Unusual asynchronous ischemia was observed in the right ventricle concomitantly with posterior left ventricular infarction, suggesting the presence of a protective mechanism against ischemia by the abundant collateral circulation of the right ventricle. In conclusion, right ventricular infarction occurs only with the cease of collateral circulation due to proximal occlusion and the presence of long thrombi in the right coronary artery.

Adult↗

PubMed1994

Dipyridamole angina: a specific symptom of severe multivessel disease.

BACKGROUND: Several studies have indicated that ischemia induced by dipyridamole is frequently associated with angina or ischemic ST-segment depression and that it occurs mainly in patients with three-vessel disease, those with collateral vessels, or those with both. METHODS: In order to analyze the diagnostic relationships among them, we studied 227 consecutive patients who underwent coronary angiography and dipyridamole-thallium scintigraphy. RESULTS: A perfusion defect was found in 134 patients. Of these, 88 patients (66%) showed no significant ECG modifications or angina; 46 (34%) had a transient ST-segment depression, which was associated with typical angina ('dipyridamole angina') in 12. These 12 patients had three-vessel disease with intercoronary collateral circulation. Among the 134 patients with coronary critical stenoses and a positive thallium-dipyridamole test, collateral vessels were detected in 91 (68%). CONCLUSION: Dipyridamole angina, occurring during a positive dipyridamole-thallium test, is usually a manifestation of severe coronary stenoses with collateral circulation. However, as a diagnostic symptom it is characterized by high specificity but low sensitivity.

Aged↗

PubMed2000

[Gene therapy with VEGF].

UNLABELLED: NEW THERAPEUTIC OPTION: Atherosclerosis-related conditions are the primary cause of mortality in western countries. The incidence of severe limb-threatening ischemia of the lower limbs reaches 500 to 1000 per million inhabitants. The lack of effective treatment capable of preventing amputation in the most severe cases has led to research into the development of collateral circulation to replace the occluded arteries. Preclinical data has demonstrated that angiogenic factors can stimulate collateral circulation. This new therapeutic approach is called "angiogenesis therapy". VEGF: Vascular endothelial growth factor (VEGF) is a DNA fragment coding for a protein that has raised great expectations which are now entering the era of reality. Several administration routes are possible. The DNA fragments can be deposited on the arterial wall using a catheter. The hydrogel balloon operates like an angioplasty balloon covered with a hydrophilic layer which delivers the DNA fragments when inflated. More recently, the intramuscular route has been used to take advantage of the vascular distribution of this angiogenic cytokine. The peripheral muscle cells can perform the transformation via transcription to a messenger RNA for translation into the human DNA protein. A real application of gene therapy. PERSPECTIVES: Undeniable clinical benefit observed in the limited number of patients treated has led to proposing angiogenic cytokines for the treatment of ischemic heart disease when angioplasty or bypass surgery. The most recent series are small, but show that intramyocardial injection of VEGF is feasible. Larger randomized series will evaluate these techniques. Despite the large body of preclinical data, many questions remain unanswered.

Animals↗

PubMed1999

Early infarct artery collateral flow does not improve long-term survival following thrombolytic therapy for acute myocardial infarction.

It is known that acutely developed collaterals can prevent the onset of acute myocardial infarction (AMI) in the presence of a total coronary occlusion. However, there still is controversy concerning long-term follow-up of coronary collateral circulation to the infarct-related artery. In this study we analyze the prognostic role of collateral flow (degrees 0 to 3) as well as anterograde flow (degrees 0 to 3) in patients with AMI treated with thrombolytic therapy. Four hundred twenty-two patients (median age 57 years, 355 men) with AMI were treated with intravenous streptokinase and followed prospectively for up to 8 years. At the end of the study period, patients with collateral coronary flow 3 (n = 30) and those with flow <3 (n = 392) at in-hospital coronary arteriography had survival rates of 66% and 85%, respectively (p <0.12). Meanwhile, patients with coronary anterograde flow 3 (n = 189) and those with flow <3 (n = 233) had survival rates of 89% and 80%, respectively (p <0.04). By censored regression analysis, a negative correlation was found between coronary collateral flow degree and survival (p = 0.0498) and, inversely, a positive correlation was found between coronary anterograde flow degree and survival (p = 0.0053). By Cox multivariate analysis, the following variables showed significant correlations with long-term survival: global left ventricular ejection fraction (p = 0.0003), anterograde flow degree (p = 0.0006), collateral flow degree (negative correlation, p = 0.0179), and medical treatment (negative correlation, p = 0.0464). Thus, patients treated with intravenous streptokinase during AMI and with adequate coronary collateral circulation had a worse prognosis than those who developed adequate anterograde flow, probably because of residual myocardial ischemia. Such patients may benefit from coronary revascularization (angioplasty or surgery) to restore anterograde blood flow and minimize myocardium at risk.

Cardiac Catheterization↗

PubMed1989

Septal collateralization: demonstration of canine intramyocardial collaterals.

The anatomical distribution of intramyocardial collateral arteries that develop from the septal to the other major coronary arteries was studied in dogs following gradual Ameroid occlusion of the circumflex artery. The septal artery was cannulated and injected with Batson's plastic compound resulting in a cast of the coronary circulation. Collateral vessels radiated from the septal vascular bed to both the circumflex and anterior descending arteries. The collaterals developed from the entire base-to-apex extent of the septal artery and were found on both the right and left sides of the septum. Collateral growth appeared to be more concentrated at the apex of the heart. The anatomical details of septal collateral circulation illustrate the importance of intramyocardial collateralization in the dog, which was thought to exhibit primarily epicardial collaterals.

Animals↗

PubMed1989

Radioisotopic splenoportography in patients with portal hypertension.

Radio-isotopic splenoportography was performed by injecting 99mTcO4- into the spleens of 46 patients with portal hypertension and 14 patients with various disorders not having portal hypertension. No collateral circulation was demonstrated in the 14 patients without portal hypertension whereas some RI-images of portosystemic collaterals were found in 40 (87.0 per cent) of the 46 patients with portal hypertension. Collaterals were divided into an ascending group and a descending group, the appearance rate of ascending collaterals being 80.4 per cent and that of descending collaterals, 41.3 per cent. There were 3 image patterns in the ascending group, namely, an AZ-pattern in which the azygos vein was demonstrated; a SC-pattern in which the RI-bolus ascended along the esophagus to the neck and the subclavian vein; and an EG-pattern which showed stagnation of the RI-bolus in the esophagogastric region. There were 4 patterns in the descending group, namely; a pattern of gastro-renal caval shunt (GR-pattern); reverse flow patterns into the umbilical or paraumbilical veins (UV-pattern); into the superior mesenteric vein (SMV-pattern); and into the inferior mesenteric vein (IMV-pattern). The appearance of the EG-pattern was seen most frequently (74.4 per cent). The usefulness of this method for surveying the collateral circulation in portal hypertension, estimating the risk of esophageal variceal bleeding and evaluating its treatments, was suggested by the results of this study.

Collateral Circulation↗

PubMed1992

Chronic reduction of myocardial ischemia does not attenuate coronary collateral development in miniswine.

BACKGROUND: Myocardial ischemia is considered to be a possible stimulus for development of the coronary collateral circulation. We therefore hypothesized that chronic reduction of myocardial oxygen demand to lessen ischemia would attenuate coronary collateral development over an 8-week period using left circumflex coronary artery (LCx) ameroid-induced constriction in pigs. METHODS AND RESULTS: Collateral development was assessed by myocardial blood flow (radioactive microspheres) and left ventricular regional function (sonomicrometer dimension gauges). beta-Adrenoceptor blockade with propranolol (160 or 320 mg b.i.d.p.o.) was initiated in 15 animals 1 day after surgery. Compared with 16 untreated animals, beta-adrenoceptor antagonism was documented in the treated group by 1) pharmacological stimulation with isoproterenol, 2) physiological stimulation during graded treadmill exercise, and 3) repeated long-term biotelemetry recordings of oxygen demand (heart rate and blood pressure) and regional myocardial function. In addition to pharmacological and physiological verification of beta-blockade, biotelemetry showed that, compared with the untreated animals, propranolol significantly reduced the daily number, individual duration, and severity of events representing myocardial dysfunction. This suggests that in the beta-blocked group, little if any ischemia was present throughout the first 5 weeks when collateral growth occurs. Transmural myocardial blood flow (expressed as a ratio of flow in the LCx region to the nonoccluded region of the left ventricle) and systolic wall thickening in the LCx region were determined at rest and during treadmill exercise (240 beats per minute) 31-38 days (5 weeks) and 60-67 days (8 weeks) after surgery. Propranolol was withdrawn 3 days before flow and function determinations and was resumed immediately after testing. Blood flow ratios at 5 weeks decreased similarly from rest to exercise in the untreated (0.83 +/- 0.04 to 0.60 +/- 0.05, p less than 0.05) and beta-blockade group (0.82 +/- 0.09 to 0.57 +/- 0.10, p less than 0.05). Systolic wall thickening from rest to exercise was attenuated to the same degree in the untreated (59 +/- 6% to 38 +/- 6%, p less than 0.05) and beta-blockade group (50 +/- 8% to 30 +/- 5%, p less than 0.05). Similar flow and function responses were observed in both groups at 8 weeks. CONCLUSIONS: We conclude that growth and development of the coronary collateral circulation measured functionally during exercise at 90% of maximal heart rate is unrelated to the extent and duration of myocardial ischemia in this model.

Animals↗