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PubMedDate not supplied

[Coronary collateral circulation and prevention of ischemic mitral regurgitation].

INTRODUCTION: According to definition, collateral circulation is an alternative to major vascular flow which has become dysfunctional. Collateral channels, initially unused, are being formed due to impossibility of the main blood vessel to provide normal coronary flow. Recent controversies about collateral circulation are mainly based on their functional significance. The aim of this work was to evaluate the function of collateral circulation in patients after the first postero-inferior myocardial infarction i.e. whether adequate collateral circulation may reduce the size of myocardial infarction and prevent development of ischemic mitral regurgitation. MATERIAL AND METHODS: The investigation included 128 patients (pts) treated at the Institute of Cardiovascular Diseases in Sremska Kamenica during 1997 and 1998. The investigation group (I) included 64 pts, 58 males and 6 females, mean age 54.42 years. The control group (C) included 64 pts, 56 males and 8 females mean age 51.71 years. In all patients the first posterior, inferior and postero-inferior myocardial infarction were proven during 1-year period. Cineventriculography confirmed kinetic disturbance of the area with or without mitral insufficiency. Degree of mitral regurgitation was evaluated according to Seller's criterion. Alterations on the right coronary or circumflex branch of the left coronary artery were confirmed, but significant stenotic alterations were not verified on the anterior descendent branch of the left coronary artery. Alterations on epicardiac coronary vessels were presented as total coronary score--modification according to Benc (18 segments) while numerical values for stenosis according to Kaltenbach. This value represents the total coronary score (SCORE-A) including alterations before and after occlusion. Gensiny's principle modified for multiplication factor according to Benc and numerical value according to Kaltenbach were used for evaluation of collateral circulation. Levin's classification was used for evaluation of collateral circulation quality. We used quantitative classification according to Cohen. RESULTS: Distribution of mitral regurgitation was not statistically and significantly frequent in the subgroup of patients with lesions on the right coronary artery in relation to subgroup of patients with combined lesions on the right coronary artery and circumflex branch of the left coronary artery (p > 0.05). None of the investigated patients with extensive lesions (lesions on ACD and RCX) had mitral regurgitation of IV degree, so the number of investigated patients was not adequate for statistical evaluation. We did not find a statistically significant difference in the percentage of collateral circulation between the investigation (59.4%) and control group (62.5%) (p > 0.05). Poorly developed collaterals were statistically and significantly more frequent in the investigation group (60.5%) in relation to control group (10%) (p < 0.01). The percentage of moderately developed collateral circulation was similar in both groups. Well developed collateral circulation was statistically and significantly more frequent in control group (52.5%) in relation to investigation group (7.9%) (p < 0.01). The extension of stenotic alterations expressed as total coronary score A was statistically and significantly higher in subgroups of investigated patients with combined alterations on ACD and RCx, proving the sensitivity of our score system in smaller extensity of stenotic lesions on epicardial coronary blood vessels. Collateral circulation was significantly better in patients with ACD occlusion (100%) in relation to patients with significant stenosis or ACD subocclusion (33.3%) (p < 0.01). DISCUSSION: The functional role of collaterals has not been explained yet. The efficacy of coronary collateral vessels and mechanism of adequate compensation of regional perfusion in a position distal from the occluded vessel is highly controversial. (ABSTRACT TRUNCATED)

Collateral Circulation↗

PubMed1975

Intrarenal arterial collateral circulation.

In three cases of intrarenal arterial collateral circulation the collateral channels developed between interlobar arteries in diseased kidneys. Probably these originated in hypertrophied spiral vessels that had arisen from the interlobar arteries in the area of the minor calyces. This form of collateral circulation will undoubtedly be recognized more frequently with the increased use of magnification radiography.

Adolescent↗

PubMed1998

[Collateral circulation and the coronary reserve].

The mechanisms regulating coronary collateral circulation are largely unknown owing to both the complex and variable nature of clinical models and the difficulty to obtain quantitative and differentiated flow measurements within the various coronary tree portions. With the aim of assessing collateral flow reserve, we studied 19 patients with effort angina, without myocardial infarction and with isolated occlusion of either the left anterior descending coronary artery (n = 14) or the circumflex coronary artery (n = 5). Flow values were measured basally, during atrial pacing induced tachycardia and following ev dipyridamole infusion (0.56 mg/kg of body weight in 4 min), by means of positron emission tomography and nitrogen-13 ammonia as flow tracer, within both regions depending on collateral circulation and the remote ones. Results have been compared with those obtained in 13 normal subjects. Basal flow values in regions depending on collateral circulation and in the remote regions (0.61 +/- 0.11 vs 0.63 +/- 0.17 ml/min/g) were found to be similar, but lower than in normal subjects (1.00 +/- 0.20 ml/min/g, p < 0.01). During atrial pacing, flow increased to 0.83 +/- 0.25 and to 1.11 +/- 0.39 ml/min/g, in the regions depending on collateral circulation and in the remote regions, respectively (p < 0.05 as compared to baseline); again, values were lower than in normal subjects (1.86 +/- 0.61 ml/min/g, p < 0.01). Dipyridamole infusion further increased flow in the remote regions (1.36 +/- 0.57 ml/min/g, p < 0.01 as compared to atrial pacing) but it did not in the regions depending on collateral circulation (0.94 +/- 0.37 ml/min/g, NS as compared to atrial pacing); both values were lower than in normal subjects (3.46 +/- 0.78 ml/min/g, p < 0.01). Flow reserve in the regions depending on collateral circulation was found to have a direct linear correlation with the one in the remote regions (r = 0.83; p < 0.01). In conclusion, in spite of basal hypoperfusion, collateral circulation maintains a flow reserve which, even if reduced, is able to cope with moderate increments in oxygen consumption. An analogous flow reduction can be observed in the remote regions, suggesting that the entire coronary tree is involved, beyond the obstructive lesions of the main arterial branches.

Adult↗

PubMed2006

The role of collateral circulation in preserving myocardial function.

The coronary collateral circulation is an alternative source of blood supply to the myocardium jeopardized by the failure of the original stenotic or occluded vessel to provide adequate blood flow to this region. One hundred coronary angiograms and left ventriculograms of patients with coronary artery disease from the Cardiology Department of University Clinics Centre in Sarajevo were reviewed. The role of collateral circulation in preserving myocardial function was assessed by comparing regional left ventricular contractility in 34 instances of total arterial occlusion and adequate colateral circulation with that in 34 instances of total arterial occlusion and inadequate collateral circulation. Among the group with adequate collaterals, regional left ventricular contraction was normal in 41%, hypokinetic in 53% and akinetic or dyskinetic in only 5%. Among the group with inadequate collaterals, regional contraction was normal in 9%, hypokinetic in 20 % and akinetic or dyskinetic in 70%. These data indicate that collateral circulation plays an important role in preserving myocardial contractility in patients with coronary artery disease.

Collateral Circulation↗

PubMedDate not supplied

Myocardial perfusion in patients with total occlusion of a single coronary artery with and without collateral circulation.

BACKGROUND: Previous studies that investigated the effects of coronary collateral circulation on myocardial perfusion were compromised by inclusion of patients with multivessel coronary artery disease, incomplete occlusion, prior myocardial infarction, or a combination of these. In this study we ascertained the relationship between angiographic collateral circulation and myocardial perfusion only in patients with total occlusion of a single coronary artery, in the absence of myocardial infarction or significant stenosis in the other coronary arteries. METHODS AND RESULTS: Seventy-one consecutive patients underwent stress myocardial single photon emission computed tomography within 90 days of angiography. Collateral circulation was present in 49 patients and absent in 22 patients. All but 2 patients had abnormal perfusion by single photon emission computed tomography imaging, with a mean defect size of 19% +/- 12%, and most (83%) had reversible perfusion defects. Defect count activities improved from stress to rest (or redistribution) (45% +/- 13% to 59% +/- 14%, P <.001). Abnormal myocardial perfusion occurred with similar frequency in patients with collateral circulation and in those without it. Total defect size was 19% +/- 12% in patients with and 18% +/- 11% in those without collateral circulation (P = not significant). The extent of reversibility and defect count activity during stress and rest were similar in patients with collateral circulation and in those without it. CONCLUSIONS: In patients with a single-vessel total coronary occlusion and without myocardial infarction, stress-induced myocardial ischemia is almost always present, irrespective of presence or absence of angiographic collaterals. These data lend support to the premise that collateral circulation is rather insufficient to prevent stress-induced ischemia, although it can preserve myocardial viability.

Aged↗

PubMed1988

[Influence of the distribution of collateral circulation on left ventricular segmental kinetics].

Correlations between left ventricular segmental kinetics and collateral circulation patterns were studied in 292 patients with coronary disease (182 women, 274 men: mean age 54 years). Left ventricular segmental kinetics were analyzed qualitatively by angiography (10 segments were individualized on RAO and LAO projections) and rated as normal, hypokinetic, akinetic or aneurysmal. The type of collateral circulation observed (contralateral, homocoronary and homolateral) and the number of collateral vessels were recorded. Collateral circulation was present in 49 p. 100 of the patients and in 29 p. 100 of the 587 pathological arteries (i.e. more than 50 p. 100 stenosis) identified. 89 p. 100 of the occluded arteries were revascularized by collateral circulation, the latter being effected by 213 collateral vessels (mean: 1.41 +/- 0.36 vessel per occluded artery). Collateral circulation through 1, 2 or 3 collateral vessels was noted in 62 p. 100, 35 p. 100 and 3 p. 100 respectively of the cases. Collateral circulation was contralateral in 51 p. 100, homocoronary in 33 p. 100 and homolateral in 16 p. 100 of the cases. Normal or hypokinetic segments in the territory of an occluded artery were more frequent in the presence (43 p. 100) than in the absence (31 p. 100) of collateral circulation, but the difference was not significant. They were also more frequent in three-vessel patients (59 p. 100) than in one-vessel (21 p. 100; p less than 0.01) or two-vessel (37 p. 100; p less than 0.05) patients in the presence of collateral circulation.(ABSTRACT TRUNCATED AT 250 WORDS)

Collateral Circulation↗

PubMed1994

Preferential dilation of recipient coronary arteries of the collateral circulation by intracoronary administration of nitroglycerin.

OBJECTIVES: The purpose of this study was to test the hypothesis that the sensitivity to nitroglycerin of collateral vessels and recipient arteries is greater than that of donor arteries of the collateral circulation. BACKGROUND: The collateral circulation responds vigorously to nitroglycerin. However, the mechanisms of the efficacy of nitroglycerin for improving collateral circulation are not fully elucidated. METHODS: The diameter of donor and recipient arteries of the collateral circulation was measured with a computer-assisted analysis system in eight patients with well developed collateral vessels. Coronary angiography was repeated before and after the intracoronary injection of 50 micrograms of nitroglycerin. RESULTS: After nitroglycerin, the mean diameter +/- SD of donor arteries increased to 1.61 +/- 0.53 from 1.29 +/- 0.39 mm (p < 0.01), whereas the diameter of recipient arteries increased to 1.59 +/- 0.50 from 1.10 +/- 0.49 mm (p < 0.01). The change in the diameter of recipient arteries was significantly greater than that of donor arteries (52.3 +/- 24.6% vs. 24.7 +/- 11.5%, p < 0.05). These changes induced by the intracoronary injection of nitroglycerin were accompanied by a decrease in pacing-induced ST segment depression (0.16 +/- 0.06 to 0.06 +/- 0.04 mV, p < 0.01), suggesting increased flow reserve through collateral channels. CONCLUSIONS: These findings indicate that the sensitivity to nitroglycerin of recipient arteries of the collateral circulation is significantly greater than that of donor arteries. This observation may explain the strong response of the collateral circulation to nitroglycerin in patients with functionally significant collateral channels.

Aged↗

PubMedDate not supplied

[Coronary collateral circulation: its importance and significance in ischemic cardiopathy].

With the purpose of studying coronary collateral circulation and if it has influence in manifestations, complications, prognosis and mortality in patients with ischemic heart disease, we studied 52 patients, 41 male and 11 female, mean age 56 years, who died. All of them had a complete medical record and were seen with regularity until death. They had good quality coronaragraphy and ventriculography. Post-mortem study was done in all of them. They were placed in two groups: group I (27 patients) who had adequate collateral circulation and group II (25 patients) without adequate collateral circulation. We found that group I patients had angina more frequently prior to myocardial infarction (p less than 0.005) with greater duration (30 months). Complications during the acute phase of myocardial infarction were more common in patients without collateral circulation (p less than 0.001). Although we did not find statistically significant differences, we could observe that patients without adequate collateral circulation have less survival, disturbances in ventricular wall mo-motion are more frequently found and there is more incidence of sudden death. There was no significant difference between the apparition of myocardial infarction in patients with or without adequate coronary collateral circulation. Diabetic patients had less collateral circulation than non diabetics (p less than 0.05). We conclude that the protective role of collateral circulation in ischemic heart disease is established, diminishing complications during acute myocardial infarction and providing for longer survival.

Adult↗

PubMed1975

Collateral circulation before and after coronary artery reconstruction.

The changes in collateral circulation after coronary artery reconstruction were analyzed in 75 patients with 177 bypass grafts and 18 complementary gas endarterectomies. The quantity of collateral circulation was directly proportional to the degree of coronary obstruction. The changes in collateral circulation depended on the success of coronary surgery or on the progression of the disease in coronary vessels. So, when the grafts remained patent, the collaterals disappeared and when the grafts became occluded, the collateral circulation returned to the preoperative level. Progressive obstruction of the coronaries caused increased collateral circulation.

Adult↗

PubMed2002

Collateral circulation in internal carotid artery occlusion. A study by duplex scan and magnetic resonance angiography.

BACKGROUND: Clinical effects of internal carotid artery (ICA) occlusion may range from the absolute absence of symptoms to lethal hemispheric stroke. In this paper symptoms of patients with ICA occlusion have been related to the development of collateral circulation, different types of developed collateral circulation have been assessed, and the degree of sensitivity and specificity of duplex scan has been appraised. METHODS: Forty-eight patients with ICA occlusion or subocclusion, 24 males and 24 females, aged between 50 and 83 years (67.7+/-7.15), underwent duplex scan and magnetic resonance (MR) angiography. Nineteen patients were completely asymptomatic, 20 patients showed permanent neurological symptoms and 9 patients had shown transient symptoms. RESULTS: Twelve patients (25%) did not show any collateral circulation, 29 patients (60%) showed collateral circulation through homolateral external carotid artery branches and 7 patients (15%) showed collateral circulation through other circuits. Of the 20 patients with permanent symptoms only 8 showed collateral circulation. On the contrary, all the 19 asymptomatic patients and the 9 patients with transient symptoms showed collateral circulation. Eventually, duplex scan showed 78% sensitivity, 100%, specificity and 83% diagnostic accuracy. CONCLUSIONS: Our data show: 1) a clear-cut prevalence of collateral circulation through homolateral external carotid artery branches with respect to other possible collateral circulation; 2) an inverse relationship between the development of collateral circulation and the appearance of permanent symptoms; 3) a good diagnostic accuracy of duplex scan in revealing collateral circulation in the case of ICA occlusion.

Aged↗

PubMed1990

[Significance of collateral circulation in reversible asynergy].

The functional role of collateral circulation in reversible asynergy of the left ventricle was evaluated. Cineventriculograms were obtained before and after the administration of sublingual nitroglycerin (0.3 mg) in 19 patients with complete occlusion of the proximal portion of the left anterior descending coronary artery. In nine patients with well-developed collateral circulation, both left ventricular ejection fraction and regional wall motion were significantly improved by nitroglycerin. By contrast, in 10 patients without significant collateral circulation, there were no detectable changes in both global and regional wall motions before and after nitroglycerin. The left ventricular hemodynamic changes caused by nitroglycerin were comparable in both groups. These findings support the view that the improvement in asynergy caused by nitroglycerin appears to depend mainly on the extent of collateral circulation, rather than on decreases in both preload and afterload.

Aged↗

PubMed1987

Importance of angina for development of collateral circulation.

The extent of collateral circulation in 46 patients who had intracoronary thrombolysis within six hours of the onset of acute myocardial infarction was evaluated. Patients who had had a previous myocardial infarction (4 cases) or who had spontaneously recanalized infarct related coronary arteries (5 cases) were excluded from the analysis. Collateral development was graded during coronary cineangiography according to the extent of opacification of the collateral and epicardial arteries distal to the site of occlusion (collateral index 0 to 3). Angina was considered to be present before myocardial infarction if it had occurred more than one week before acute myocardial infarction. Collateral channels were visible in only two of 19 patients without angina before infarction and nine of the 18 patients with angina before infarction. The prevalence of angina and the collateral index were not significantly influenced by the extent of coronary vessel disease. It is concluded that myocardial ischaemia is important in promoting collateral development in man as well as in laboratory animals.

Adult↗

PubMed1990

Development of collateral circulation after acute myocardial infarction: its role in preserving left ventricular function.

The present study evaluated the effects of coronary collateral circulation developing after acute myocardial infarction on global and regional left ventricular function during the chronic stage. The study group consisted of 16 patients with initial myocardial infarction having total occlusion of the proximal left anterior descending coronary artery. To eliminate the effects of collateral circulation existing at the onset of infarction, patients with pre-infarction angina were excluded from this study. The patients were categorized in two groups depending on the extent of their collateral circulation (collateral index: CI 0-3): group A--patients with significant collateral circulation (CI = 2 or 3) to the infarct-related coronary artery; group B--patients without significant collateral circulation (CI = 0 or 1). Their heart rate, left ventricular peak systolic and end-diastolic pressures and cardiac index were similar in the two groups. The left ventricular end-systolic volume index in the group B was significantly greater than that in the group A (60 +/- 21 ml/m2 vs 34 +/- 9 ml/m2, p less than 0.05). Left ventricular ejection fraction in the group A was significantly greater than that of the group B (55 +/- 9% vs 39 +/- 15%, p less than 0.05), and a significant difference was observed in the percentage of segment shortening in the infarct area between the groups A and B (10.8 +/- 9.2% vs -0.2 +/- 5.4%, p less than 0.01). It was concluded that coronary collateral circulation which develops after acute myocardial infarction exerts beneficial effects on global and regional left ventricular function during the chronic stage.

Adult↗

PubMed1991

Influence of minimal angiographic visible collateral circulation on myocardial function during PTCA.

The potential protective role of angiographically visible minimal collateral circulation in diagnostic angiograms, not reaching or filling the target vessel (RENTROP class 1), on myocardial function during percutaneous transluminal coronary angioplasty (PTCA), was studied in two groups of patients undergoing elective PTCA of the left anterior descending artery (LAD). In the first study group consisting of 22 patients, influence of collateral circulation class 1 on left ventricular regional function was evaluated. In this group, 14 patients showed no angiographic collaterals and 8 patients showed collateral circulation class 1 in diagnostic angiograms. Increase of end-diastolic and end-systolic volume indices as well as decrease of global left ventricular function was not significantly different inpatients with and without such minimal collateral circulation. In patients without collaterals, the decrease of regional left ventricular function was significantly more pronounced in the left anterior length segment (p less than 0.05) and a trend was observed in the anterolateral (p = 0.059) and apical (p = 0.053) segments. In a second group, consisting of 29 patients, hemodynamic parameters were measured and, in addition to grading of collateral circulation in diagnostic angiograms, angiographically visible collateral circulation was estimated during occlusion of the LAD by injecting contrast materials into the right coronary artery. An increase of angiographically visible collaterals during the ischemic period of various degrees was documented in 26 (90%) of 29 patients. Combining patients of both study groups, increase in left ventricular end-diastolic pressure during ischemia was significantly higher (p less than 0.05) in patients without collaterals on diagnostic angiography (n = 34) than in patients with collateral circulation class 1 (n = 14).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMed1985

Assessment of digital blood flow and palmar collateral circulation. Allen's test vs. photoplethysmography.

Collateral circulation of the hand and digits was evaluated in 20 healthy male volunteers using a modified Allen's test and photoelectric plethysmography. A borderline (7-14 sec) Allen's test was present in 12.5% and 2.5% required more than 15 seconds for thenar flush. Photoplethysmography was then used to compare the relative contributions of ulnar artery flow to total arterial flow into the hand. This ratio, (ulnar/total) was termed the flow index (FI). Average FI for the first digit (thumb) was 0.59, and for the second digit (index) was 0.64. The FI difference between the first digit and that of the third, fourth and fifth digits was statistically significant (p less than 0.01). The FI difference between the second digit and the third, fourth and fifth digits was also statistically significant (p less than 0.05). These results imply that Allen's test may be misleading, indicating adequate collateral circulation when in fact collateral blood flow to the digits may be poor or nonexistent.

Adult↗

PubMed1991

Coronary collateral circulation.

The occurrence and influence of coronary collateral circulation and obstruction of the supplying coronary arteries on left ventricular contractility, prevalence of myocardial infarction, and bicycle exercise ergometer test were studied in a random sample of 286 patients with angiographically documented coronary artery disease. Collaterals appeared increasingly in all three main coronary arteries with grade of obstruction. The highest prevalence of collaterals occurred in stenosis of the right coronary artery (60%), followed by the left descending artery (45%); they occurred least in the left circumflex artery (21%) (p less than 0.001). The frequency of intra-arterial collateral circulation was 42%, 11%, and 12%, respectively (p less than 0.001). With total occlusion of the left anterior descending coronary artery, 22% of the patients had normokinetic anterior and apical left ventricular wall when collaterals were present. More often, the inferior wall showed normal contraction with total occlusion of the right coronary artery and collaterals [52%, p less than 0.001 compared with left anterior descending artery (LAD)]. The prevalence of inferior myocardial infarction was 39%, with collateral circulation to the totally occluded right coronary artery. The respective prevalence of anterior infarction and total occlusion in the left coronary artery was 58% (p less than 0.02). The presence or absence of collaterals had no obvious influence on ST-segment response during bicycle ergometer test. In triple-vessel disease, peak work capacity was better when collaterals to LAD were not jeopardized (427 kpm) than when jeopardized (321 kpm) (p less than 0.02).

Analysis of Variance↗

PubMed1990

A prospective angiographic study of the coronary collateral circulation in coronary arterial disease.

A prospective angiographic study of the coronary collateral circulation was performed in 600 consecutive patients found to have significant coronary arterial disease at cardiac catheterization. As the number of diseased coronary vessels increased the evidence of collaterals rose significantly (P = 0.00002) and the intensity of the collateral circulation increased (P = 0.05). For totally occluded lesions the collateral incidence was 70.4%, independent of the particular vessel involved. For stenoses greater than 90% collateral frequency and intensity were significantly greater for lesions of the right coronary artery than of the left anterior descending and the left circumflex arteries. The distribution of the coronary collateral circulation is described quantitatively according to the site of the lesion. Finally, a coronary collateral circulation occurred more frequently (P less than 0.000 001) and excepting Grade I, the intensity of the coronary collateral circulation was significantly greater in patients with a history of acute myocardial infarction.

Analysis of Variance↗

PubMed1978

The behavior of collateral circulation after coronary artery bypass surgery.

The changes in coronary collateral circulation after bypass surgery were analyzed in 50 patients with coronary disease. The demonstration of collateral circulation was found to be dependent upon the severity of the coronary heart disease and the patency of the bypass. When the graft was patent, it was usually not possible to visualize the collateral circulation demonstrated preoperatively. When the bypass was occluded, the same collateral circulation as before surgery was frequently found.

Collateral Circulation↗