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Biomedical subjects

W Flameng

Publications and source records attributed to W Flameng.

At least 199 records · Page 11Linked to original sources
PubMed1987

Emergency coronary bypass grafting for evolving myocardial infarction. Effects on infarct size and left ventricular function.

Emergency aorta-coronary bypass grafting was performed early in the course of evolving myocardial infarction in 48 patients. The time interval between the onset of symptoms and reperfusion was 169 +/- 80 minutes. Quantitative assessment of postoperative thallium 201 myocardial scans in 19 patients revealed a significant salvage of myocardium after surgical reperfusion: The size of the residual infarction was less than 50% of that in a matched, medically treated, prospective control group (n = 39) (p less than 0.05). Postoperative equilibrium-gated radionuclide blood pool studies (technetium 99m) showed an enhanced recovery of regional and global ejection fraction after operation as compared to after medical treatment (p less than 0.05). Ultrastructural evaluation of biopsy specimens obtained during the operation delineated subendocardial necrosis in the majority of cases (72%), but subepicardial necrosis was found in only 6% of instances. Q-wave abnormalities were observed on the postoperative electrocardiogram in 50% of cases. Operative mortality was 0% in low-risk patients (i.e., hemodynamically stable condition, n = 26) and 18% in high-risk patients (i.e., cardiogenic shock including total electromechanical dysfunction, n = 22). Survival rate at 18 months was 92% +/- 4%, and 95% +/- 4% of the survivors were event free. It is concluded that early surgical reperfusion of evolving myocardial infarction limits infarct size significantly, enhances functional recovery, and may be a lifesaving operation in patients having cardiogenic shock associated with unsuccessful resuscitation.

Actuarial Analysis↗
PubMed1986

Coronary thrombolysis by intravenous infusion of recombinant single chain urokinase-type plasminogen activator or recombinant urokinase in baboons: effect on regional blood flow, infarct size and hemostasis.

An occlusive thrombus was produced by thrombin-induced coagulation in the left anterior descending coronary artery of 18 open chest baboons. In six control animals, occlusive thrombosis persisting for 4 hours resulted in a large transmural infarct (66 +/- 4% of the perfusion area, mean +/- SEM). In six animals, single chain urokinase-type plasminogen activator, obtained by recombinant deoxyribonucleic acid (DNA) technology, was infused intravenously at a rate of 20 micrograms/kg per min for 60 minutes after approximately 45 minutes of coronary thrombosis. Persistent reperfusion occurred within 21 +/- 4 minutes (mean +/- SD). The mean duration of occlusion before reperfusion was 72 +/- 6 minutes. Recanalization resulted in a reduction of infarct size (42 +/- 4%, p less than 0.01 versus control animals). Myocardial blood flow in the perfusion area of the left anterior descending coronary artery was 107% of normal 2.5 hours after recanalization. The infusion of recombinant single chain urokinase-type plasminogen activator was not associated with systemic activation of the fibrinolytic system, fibrinogen breakdown or evident bleeding. In six baboons recombinant low molecular weight urokinase (molecular weight 33,000) was infused intravenously at a rate of 20 micrograms/kg per min for 60 minutes after approximately 45 minutes of coronary thrombosis. Persistent reperfusion occurred within 14 +/- 5 minutes (p less than 0.05 versus recombinant single chain urokinase-type plasminogen activator). The mean duration of occlusion was 69 +/- 14 minutes.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1986

Studies on experimental myocardial infarction: dogs or baboons?

The extrapolation to humans of results obtained in experimental studies is a major problem in cardiovascular research. It is generally believed that non-human primates provide a better model for the study of experimental myocardial infarction than the canine or porcine heart. In the present study the transmural distribution of myocardial infarction and collateral flow were compared between dogs and baboons. In the open chest model, the left anterior descending coronary artery was ligated for 4 h. In the subepicardial and subendocardial portions of the left ventricle myocardial blood flow was measured with tracer microspheres, and infarct size and site were determined using triphenyl tetrazolium chloride. In baboons, mean(SD) subendocardial collateral flow was higher than subepicardial collateral flow (41.8(24.6) ml . min-1 X 100 g-1 vs 28.6(21.3) ml . min-1 X 100 g-1 (p less than 0.05)). Subendocardial infarct size (expressed as a percentage of the perfusion area) was smaller than subepicardial infarct size (50.3(8.5)% vs 61.2(9.6)% (p less than 0.001)). In dogs, subendocardial collateral flow was less than subepicardial collateral flow (10.2(6.0) ml . min-1 vs 13.6(4.6) ml . min-1 X 100 g-1 (p less than 0.05)), and subendocardial infarct size was greater than subepicardial infarct size (67.3(12.9)% vs 38.3(18.0)% (p less than 0.01)). When, irrespective of the species or transmural localisation, infarct size is related to collateral flow, expressed as a percentage of normal flow, a weak but significant correlation is obtained (r = 0.61, p less than 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1986

Changes in creatine phosphate, inorganic phosphate, and the purine pattern in dog hearts with time of coronary artery occlusion and effect thereon of mioflazine, a nucleoside transport inhibitor.

A detailed analysis was made of the changes in canine myocardium, with time of occlusion, in several important metabolites such as creatine phosphate and adenosine triphosphate (luminometry), inorganic phosphate (spectrophotometry), and most of the purines and nicotinamide adenine dinucleotide (high performance liquid chromatography). Within 1 min there was a significant reduction in creatine phosphate and a significant increase in inorganic phosphate, adenosine diphosphate, and adenosine monophosphate. A decrease in adenosine triphosphate became apparent after 4 min, concomitant with a progressive rise in the nucleosides, which reached almost 50% of the total purines after 64 min of occlusion. The formation of hypoxanthine was detectable in 50% only of all animals, suggesting a lack of active nucleoside phosphorylase in the others. Nicotinamide adenine dinucleotide, although decreasing slightly, was by far the most constant of all variables measured during at least 30 min of ischaemia. Therefore, this component is suggested to be a useful internal standard, thus minimising analytical and biological variations. Mioflazine, a potent nucleoside transport inhibitor (I50 3 X 10(-8) mol X litre-1), when given orally at 2.5 mg X kg-1, did not affect any of the changes with the exception of the nucleosides, where the drug completely inverts the adenosine to inosine ratio. The contribution of adenosine to the total nucleosides changed from 20% in the controls to 80% with treatment during at least 16 min of occlusion, there being no overlap between the groups. It is concluded therefore that adenosine is not deaminated in the cell where it is produced. It is not yet clear how this notable effect of mioflazine could be linked to its remarkable protective effect against ischaemia.

Animals↗
PubMed1986

A biochemical and ultrastructural study on myocardial changes during aorto-coronary bypass surgery: St. Thomas Hospital cardioplegia versus intermittent aortic cross-clamping at 34 and 25 degrees C.

The changes induced by continuous aortic cross-clamping in combination with multidose ice-cold St. Thomas Hospital cardioplegia (myocardial temperature below 16 degrees C), or intermittent aortic cross-clamping at 34 or 25 degrees C were evaluated in a randomized study on 72 patients undergoing extensive aorto-coronary bypass surgery. The cumulative release of heart-specific enzymes was very small and no marked ultrastructural changes in mitochondria of both the subepi- and the subendocardial layer of the left ventricular free wall occurred. No differences between the three operation techniques could be observed on the basis of the above-mentioned parameters. Myocardial ATP and glycogen contents were decreased in post-ischaemic tissue in both the normothermic and hypothermic intermittent aortic cross-clamp groups. This decrease was associated with a release of lactate and inorganic phosphate during the repetitive periods of reperfusion. No change in myocardial ATP and glycogen content could be observed in the cardioplegia-treated hearts. St. Thomas Hospital cardioplegia is obviously most effective in preventing changes in myocardial metabolism such as reduction of ATP and carbohydrate stores during the reversible phase of ischaemic insult.

Adenosine Triphosphate↗
PubMed1986

How predictable is the postoperative work resumption after aortocoronary bypass surgery?

The number of aortocoronary bypass procedures increased at the Cardiovascular Surgery Department of the University Hospital in Leuven (Belgium) from 12 patients in 1971 to 650 patients in 1983. A similar evolution took place in the other existing Belgian cardiovascular centers and new departments were created to fill this need. The financial burden of the direct hospital costs of these procedures on the National Health Care program is considerable. The postoperative work-resumption will restore the patient's social dignity, it can increase the patient's personal income and thus decrease the indirect costs such as workmen's compensation; it will therefore improve the cost effectiveness of coronary surgery so that it can be offered to the numerous patients who need it for their survival or for the improvement of their quality of life. Studies about the employment status before and after aortocoronary surgery, as published from other centers, can not be projected on the Belgian situation due to the difference in population cohorts, laws regulating the working conditions, the national unemployment ratio and disability compensations. With this in mind, a study of the preoperative and postoperative employment and its predictability was undertaken.

Adult↗
PubMed1986

Nifedipine as an adjunct to St. Thomas' Hospital cardioplegia. A double-blind, placebo-controlled, randomized clinical trial.

The cardioprotective effect of the addition of the slow calcium-channel blocker nifedipine to cardioplegic solution was tested in two double-blind placebo controlled randomized studies. The first study included 24 patients undergoing aortic-coronary bypass grafting, and the second included 24 patients undergoing aortic valve replacement. Nifedipine at a dose of 200 micrograms/L or placebo was added to St. Thomas' Hospital cardioplegic solution. The following markers of ischemia were used: adenosine triphosphate and its catabolites, creatine phosphate and inorganic phosphate, determined in transmural left ventricular biopsy specimens taken before, at the end of, and after aortic cross-clamping; hemodynamic recovery 15 minutes after cessation of cardiopulmonary bypass; clinical outcome in terms of the incidence of arrhythmias, low cardiac output, positive inotropic support immediately after operation, and follow-up at 15 months. The main difference between the two studies was that myocardial temperature during cross-clamping remained constant at 14 degrees C in coronary bypass grafting but increased to 25 degrees C in valve operations despite the application of the same amounts of cardioplegic solutions. This lower temperature resulted in better preservation of high-energy phosphates in coronary bypass operations as compared to the placebo group having valve replacement operations. According to analysis of variance, a drug effect could be demonstrated only in the aortic valve replacement study: Accumulation of breakdown products of the adenine nucleotide pool was less in the nifedipine group than in the placebo group (p less than 0.05). Adenosine triphosphate decreased only to 84% in the nifedipine group and to 72% in the placebo group. Despite this adenosine triphosphate-sparing effect, weaning from cardiopulmonary bypass was more difficult in the nifedipine group. Left ventricular stroke work index 15 minutes after bypass was decreased to 72% of the prebypass value in the nifedipine group (t test, p less than 0.01) and only to 86% in the placebo group (p = NS). In contrast, after the patients were admitted to the intensive care unit, the incidence of low cardiac output tended to be lower in the nifedipine group than in the placebo group: 33% versus 58% (p = NS). In conclusion, ischemia-induced degradation of nucleotides as it occurs when myocardial cooling is inadequate can be prevented by the addition of nifedipine to the St. Thomas' Hospital cardioplegic solution. This effect, however, is not associated with an improved clinical outcome.

Adult↗
PubMed1985

Enzymatic assessment of myocardial necrosis after cardiac surgery: differentiation from skeletal muscle damage, hemolysis, and liver injury.

Plasma activities of various (iso)enzymes were measured in patients after cardiac surgery (n = 114) and after acute myocardial infarction (n = 40). From these activities, the cumulative release of enzymes in plasma was calculated with a two-compartment circulatory model. This model was adapted to transient postoperative changes in plasma volume and similar changes in the transcapillary escape rate of proteins, observed after cardiac surgery and verified in dogs after cardiopulmonary bypass (CPB). Comparison of cumulative release of enzymes with the enzyme content of myocardium, skeletal muscle, and blood cells allows identification of the various sources of enzyme release. Cardiac injury after uncomplicated bypass surgery is only 1.5 +/- 1.5 (mean +/- SD) gram equivalents (gmEq) of myocardium, compared to a loss of 31 +/- 13 gmEq of myocardium after AMI. Peroperative hemolysis is estimated at 68 +/- 15 ml of blood. Total loss of skeletal muscle amounts to 13 +/- 10 gmEq. Some hepatic enzyme release is observed after AMI but not after surgery. Large differences in time course exist between the release of enzymes from myocardium and skeletal muscle and also between myocardial release in the surgery group and in the AMI group. The accuracy of estimations is discussed and indicated as a function of the extent of cardiac injury.

Animals↗
PubMed1985

Coronary thrombolysis and infarct size reduction after intravenous infusion of recombinant tissue-type plasminogen activator in nonhuman primates.

Occlusive thrombus was produced by thrombin-induced coagulation in the left anterior descending coronary artery (LAD) of 16 open-chest baboons. In six control animals, occlusive thrombosis persisting over a period of 4 h as evidenced by coronary arteriography resulted in large transmural infarction (63.1 +/- 3.5% of the perfusion area). In 10 animals, tissue-type plasminogen activator obtained by recombinant DNA technology (rt-PA) was infused systemically at a rate of 1,000 IU (10 micrograms)/kg per min for 30 min after 30-80 min of coronary thrombosis. Reperfusion occurred within 30 min in nine animals. In one animal, intravenous infusion was followed by an intracoronary infusion at the same rate, which resulted in thrombolysis within 8 min. In the rt-PA group, mean duration of occlusion before reperfusion was 77 +/- 24 min. Reocclusion occurred in one animal. Recanalization resulted in an overall reduction of infarct size (37.8 +/- 5.9%, P less than 0.05 versus controls). Residual infarction was related to the duration of occlusion (r = 0.80, P less than 0.01). Reperfusion was associated with reduced reflow. Myocardial blood flow in the perfusion area of the LAD was only 70% of normal after 4 h despite perfect angiographic refilling. The infusion of rt-PA was not associated with systemic activation of the fibrinolytic system, fibrinogen breakdown, or clinically evident bleeding. It is concluded that intravenous infusion of rt-PA may recanalize thrombosed coronary vessels without inducing systemic lysis. The extent of residual infarction is closely related to the duration of coronary artery occlusion before thrombolysis.

Angiography↗
PubMed1985

Emergency bypass surgery: late effects on size of infarction and ventricular function.

Using thallium myocardial scintigraphy and radionuclide ventriculography, we assessed size of infarction and left ventricular function at late follow-up (greater than 2 months) in 13 patients who underwent emergency coronary artery bypass surgery (ECABS) during evolving myocardial infarction and in 26 controls who received conventional treatment for acute infarction. Thallium scans were quantitatively analyzed. The thallium defect, expressed as a numerical value in arbitrary units, was smaller after early revascularization (within 4 hr of the onset of symptoms, n = 10) than in the controls: 397 +/- 232 vs 2779 +/- 972 for anterior infarction (p less than .001) and 475 +/- 511 vs 1454 +/- 960 for inferior infarction (p less than .05). The patients undergoing revascularization late (4 to 5 hr after the onset of symptoms, n = 3) had thallium defects comparable to those in the controls. Regional ejection fraction of the involved left ventricular segment was higher after early revascularization (41 +/- 9% vs 21 +/- 8% for anterior infarction, p less than .005; 67 +/- 14% vs 51 +/- 11% for inferior infarction, p less than .01). Global ejection fraction was higher after early revascularization in patients with anterior infarction (57 +/- 10% vs 37 +/- 9%, p less than 0.02), but not in those with inferior infarction (60 +/- 11% vs 54 +/- 8%, p greater than .05). After late revascularization, regional and global ejection fraction were comparable to those in controls. In selected patients, early reperfusion of acutely ischemic myocardium by ECABS can limit size of infarction and preserve left ventricular function, but time constraints may be severe.

Adult↗
PubMed1984

Cardioprotective effects of mioflazine during 1 h normothermic global ischaemia in the canine heart.

The cardioprotective effects of mioflazine, a recently developed cardiovascular drug, were investigated in 41 anaesthetised open chest Beagle dogs subjected to 1 h normothermic global myocardial ischaemia. The severity of the model is evidenced by the finding that only one out of 20 control dogs could be weaned from extracorporeal bypass. Oral pretreatment with mioflazine (2.5 mg X kg-1) resulted in complete functional recovery in 17 out of 20 animals. Biochemical analysis of left ventricular biopsies taken before, during and after aortic cross clamping showed a preservation of purines and a better recovery of ATP, ATP/ADP X Pi ratio and energy charge (p less than 0.05) in the pretreated animals. Morphological and cytochemical assessment of the myocardium demonstrated that the ultrastructure of the sarcolemma and its calcium binding capacity is remarkably well preserved in the drug treated animals. These results indicate a strong cardioprotective effect of mioflazine. The biochemical, cytochemical and ultrastructural findings suggest an interaction of the drug with the sarcolemma.

Animals↗
PubMed1984

Multivariate analysis of angiographic, histologic, and electrocardiographic data in patients with coronary heart disease.

In 61 consecutive patients undergoing aortocoronary bypass grafting, angiographic and electrocardiographic (ECG) changes were studied. Histologic delineation of myocardium was obtained by analysis of transmural biopsy specimens acquired at the time of surgery. The use of principal-component analysis revealed three definite groups of patients. Group I comprised patients with histologic findings associated with severe left anterior descending coronary artery (LAD) stenosis, without abnormal wall motion or ejection fraction. ECG abnormalities were limited to ST changes. Group II comprised patients with severe myocardial cell degeneration with only modest fibrosis associated with severe LAD stenosis and severely impaired wall motion. The incidence of infarction on the ECG was low. Group III patients had important myocardial cell degeneration with severe fibrosis associated with severe LAD stenosis, severely depressed wall motion, and significantly impaired ejection fraction. In this group there was a high incidence of infarction apparent on the ECG. Postoperative follow-up (24 months) showed a total survival of 94.4% in group I, 92.8% in group II, and only 72.7% in group III. This identification of subtypes of coronary artery disease seems to be helpful in estimating patient prognosis after coronary surgery.

Adult↗
PubMed1984

Intermittent aortic cross-clamping versus St. Thomas' Hospital cardioplegia in extensive aorta-coronary bypass grafting. A randomized clinical study.

Myocardial preservation was assessed in 72 patients undergoing extensive myocardial revascularization. The patients were allocated at random to three surgical techniques: Group 1, intermittent aortic cross-clamping at 32 degrees C; Group 2, intermittent aortic cross-clamping at 25 degrees C; and Group 3, St. Thomas' Hospital cardioplegia. As intraoperative markers of ischemic damage, adenosine triphosphate, creatine phosphate, and glycogen contents were determined in transmural left ventricular biopsy specimens taken at the beginning and at the end of cardiopulmonary bypass. Ultrastructure was studied in a similar pair of biopsy specimens. Release of myocardium-specific creatine kinase isoenzyme was determined intraoperatively and postoperatively. Functional recovery was assessed before and after weaning from cardiopulmonary bypass. The incidence of low cardiac output, myocardial infarction, and rhythm disturbances was compared between groups. Finally, actuarial survival and event-free curves were studied after 18 months' follow-up. The results show a better preservation of high-energy phosphates, glycogen, and ultrastructure in the cardioplegia group as compared to the two cross-clamp groups. However, severe myocardial damage was never observed. Release of MB creatine kinase isoenzyme was the same in all three groups. Functional recovery of the hearts immediately after cessation of cardiopulmonary bypass was better in the cardioplegia group, but the incidence of rhythm disturbances (atrioventricular conduction problems) was higher in the cardioplegia group than in the other two groups (p less than 0.05). Clinical outcome in terms of incidence of perioperative infarction, survival, and event-free follow-up was not different between groups. It is concluded that both techniques (aortic cross-clamping at 32 degrees C or 25 degrees C and St. Thomas' Hospital cardioplegia) offer good myocardial protection in extensive aorta-coronary bypass operations. St. Thomas' cardioplegia, however, in contrast to intermittent aortic cross-clamping, prevents the onset of ischemia-induced deterioration of cardiac metabolism, i.e., destruction of the adenine nucleotide pool.

Adenosine Triphosphate↗
PubMed1984

Beneficial effect of mioflazine in limiting myocardial infarct size in the anesthetized dog.

The effect of mioflazine (R 51 469) on infarct size was studied in anesthetized dogs subjected to 24 h of LAD (left anterior descending) coronary artery occlusion. The myocardium normally supplied by the occluded coronary artery (perfusion area, PA) was delineated by perfusion of the arterial bed distal to the occlusion with colorless fluid while the remainder of the heart was simultaneously perfused with an Evans blue solution. After sectioning the heart, infarct areas (IA) could be visualized by incubation of the slices in triphenyl-tetrazolium-chloride (TTC). Quantification of the areas was performed using a Quantimet 900 image analysis system. The animals either received mioflazine (2.5 mg X kg-1 orally) or a same volume of 20% polypropylene glycol, the solvent of mioflazine 2.5 h before the start of the surgical procedure. For perfusion areas greater than 20% of the left ventricle infarct size was significantly reduced in mioflazine pretreated animals compared with the control group, both expressed as per cent of the left ventricle (10.6 +/- 2.3 vs 19.2 +/- 1.5, p less than 0.005) and as per cent of the perfusion area (35.1 +/- 7 vs 64.4 +/- 5, p less than 0.005).

Anesthesia↗
PubMed1983

Serum-myocardium gradients of non-esterified fatty acids in dog, rat and man.

In the three species under investigation (dog, rat and man) a gradient from serum to heart tissue for total non-esterified fatty acids was assessed. The ratios serum/left ventricular tissue in dogs, serum/right auricular appendage in dogs, serum/whole heart tissue in rats and serum/right auricular appendage in man were found to be 6.4, 2.5, 5.6 and 2.8, respectively. The highest gradient was found for oleic acid, whereas no significant gradient for arachidonic acid could be detected. In the dog the arterio:local venous differences of non-esterified fatty acids across the left ventricular tissue correlated better with the serum/tissue ratio of non-esterified fatty acids than with the arterial non-esterified fatty acid level. Since the correlation coefficient (0.74) was still far from excellent, more factors than the non-esterified fatty acid serum/tissue gradient are likely to be involved in determining the extent to which non-esterified fatty acids are extracted by myocardial tissue.

Animals↗
PubMed1983

Cardioprotective effects of lidoflazine in extensive aorta-coronary bypass grafting.

The cardioprotective effects of lidoflazine, a calcium entry blocker, were tested in patients undergoing multiple aorta-coronary bypass grafting (at least four grafts). Intermittent aortic cross-clamping at 25 degrees to 28 degrees C was used. Mean cross-clamp time was 11 minutes for one distal anastomosis. Patients were randomized into three groups: a control group (I), a group (II) pretreated with 0.5 mg . kg-1 lidoflazine intravenously before cardiopulmonary bypass (CPB), and a group (III) pretreated with 1 mg . kg-1 lidoflazine intravenously. The following markers of ischemia are used: (1) adenosine triphosphate (ATP), creatine phosphate (CP) and glycogen determined in transmural left ventricular biopsy specimens taken at the beginning and end of CPB; (2) ultrastructure in a similar pair of specimens; and (3) hemodynamic recovery 15 minutes after cessation of CPB. At the end of the intervention, ATP decreased to 73% in Group I but remained unchanged in Groups II (98%) and III (88%). CP decreased to 82% in Group I and remained unaltered in Groups II (100%) and III (110%). Glycogen decreased in Group I (to 44%) and in Group II (78%) but remained unchanged in Group II (138%). Ultrastructural study showed better preservation of the glycocalyx and sarcolemma in Group III than in Group I. Left ventricular stroke work index remained unaltered after CPB in Group III but decreased in Groups I and II to about 60% of its initial value. Thus lidoflazine pretreatment protects the myocardium in a dose-dependent manner against deterioration of myocardial function and structure.

Adenosine Triphosphate↗
PubMed1982

Coronary collateral vessels: their significance for left ventricular histologic structure.

Whether coronary collateral vessels protect the left ventricular myocardium is unknown. Light microscopic morphometry was carried out on myocardial tissue samples from 56 surgically treated patients with coronary artery disease. Transmural biopsy of the myocardium perfused by the left anterior descending coronary artery was obtained during open heart surgery. In initial reproducibility studies of biopsy samples of 17 patients a sampling error for evaluation of myocardium was defined and differences in transmural fibrosis exceeding +/- 6.2 percent were considered biologically significant. Stenosis of the left anterior descending artery was determined from preoperative angiography. Group A (control group) comprised patients with less than 75 percent area reduction of the left anterior descending coronary artery (mean +/- standard deviation 65 +/- 10 percent). Patients in group B (more than 95 percent area reduction [mean 99 +/- 2 percent] without collateral supply on arteriography) were compared with patients in group C (identical stenosis [mean 99 +/- 2 percent] but with collateral supply). Fibrosis averaged 17 percent in group A, 68 percent in group B (p less than 0.001 versus group A) and 29 percent in group C (p greater than 0.05 versus group A, p less than 0.001 versus group B). Thus, in severe coronary stenosis myocardium supplied by collateral vessels shows less fibrosis on biopsy sample than does myocardium without collateral supply.

Adult↗