Growth of coronary artery branches--morphometric studies of corrosion preparations of the interventricular branch of the left coronary artery in the pig and piglet

In corrosion casts of the left anterior descending coronary artery and its branches of higher anterior order, their length, diameter, and number of branches were examined in hearts of seven mature and seven young pigs. We systematically analyzed 95 branches in the corrosion casts of the mature pig hearts and 76 branches within the corrosion casts of the young pig hearts (left anterior descending coronary arteries and branches of 1st-5th order). The lengths of the branches of 1st order and the diameters of the branches of 1st and 2nd order had increased to the same degree as the lengths and diameters of the main trunk of the left anterior descending coronary artery and the linear measurements of the hearts. In the area of the more peripherally located branches, the differences showed a tendency to decrease. The number of branches differed only slightly between mature pigs' and young pigs' corrosion casts. These results show that during physiologic growth, no or only unremarkable new development of coronary artery branches occurs.     

A quantitative study of the anatomy and distribution of coronary arteries in swine in comparison with other animals and man

The coronary circulation of swine was studied to establish adequate baseline information for using swine in cardiovascular research. Of 65 hearts from domestic and miniature pigs, 45 were injected with a methacrylate plastic and prepared as coronary artery casts whose branches were described and measured, and 20 were injected with different coloured dyes in the right, left anterior descending, and circumflex coronary arteries so that horizontal sections of the heart showed the distribution of each artery and the source of blood supply to particular areas or structures of the heart. Like man, the swine had a left coronary artery that was larger in diameter and longer than the right coronary artery. The right coronary artery was almost always dominant (78%), supplying the posterior septum and atrioventricular node via the posterior descending coronary artery. Eight (17%) of the hearts possessed a balanced blood supply. Two (5%) hearts had a left dominant supply. The intracoronary artery dye injections showed that 72.4% of the right ventricular mass was supplied by the right coronary artery and 27.6% by the left anterior descending coronary artery. In the left ventricle 49% of the mass was supplied by the left anterior descending coronary artery, 25.5% by the right coronary artery, and 25.5% by the circumflex coronary artery. The left anterior descending coronary artery supplied 58% of the interventricular septal mass, while the posterior descending coronary artery supplied 42%. The distribution of the left anterior descending coronary artery branches to the ventricular wall varied inversely in number and size of its diagonal branches (2-9) with the obtuse marginal branches of the circumflex coronary artery which were occasionally more numerous or extended to the apex. The blood supply to the sinoatrial node was always by a branch of the right coronary artery. This analysis shows that not only the coronary anatomy but also the distribution of blood supply to particular areas or structures of the swine heart are very similar to that of humans.     

Quantitative morphologic studies for localizing arteriosclerotic plaques in the circumference of coronary arteries

In order to determine the distribution of arteriosclerotic plaques in the circumference of coronary arteries 150 hearts were investigated using two different methods. In 100 hearts the coronary vessels were opened longitudinally, and the sites of sclerotic lesions were mapped. The coronary arteries of another 50 hearts were filled with contrast medium, angiography was performed and the arteries were cut into 0.5-cm segments. The first 6 cm of the left anterior descending and the left circumflex arteries and the first 9 cm of the right coronary artery were studied. Segments of 1-cm length in the 100 hearts and of 0.5-cm length in the 50 hearts were examined. It was found, that arteriosclerotic lesions of the coronary arteries are most frequently located on the myocardial side of the vessel circumference. This phenomenon is most evident in the left anterior descending artery, thus possibly being caused by the most pronounced fixation of this artery on the myocardium.     

Post-mortem angiographic and histologic findings of coronary artery fibromuscular dysplasia

The present report highlights on exceptional angiographic and histologic features of coronary artery fibromuscular dysplasia in a young man complaining of chest discomfort during strenuous exercise. The striking features of fibromuscular dysplasia were the relative proximal localization of the lesion in left anterior descending coronary artery, the extensive length of the lesion, and the exclusive involvement of the intima producing a diffuse regular narrowing lesion. An eccentric intimal proliferation of the small left anterior descending coronary artery branches along their epicardial and intramural course was additionally demonstrated. No involvement of other coronary arteries or arteries of any other organs was observed.     

Short left coronary artery trunk as a risk factor in the development of coronary atherosclerosis. Pathological study.

The relation between the length of the main left coronary artery and the degree of atherosclerosis in its branches was studied by postmortem examination in 204 subjects aged 20 to 90 years. The findings suggest that in cases with a short main left coronary artery the atherosclerotic lesions in the anterior descending and circumflex branches appear earlier, progress faster at higher levels of severity, and lead more frequently to myocardial infarction, than in cases with a long left coronary artery trunk. In cases over the age of 50 years, where disease is expected to have developed, it was shown that the degree of atherosclerosis in the left anterior descending and circumflex branches was inversely related to the length of the main left coronary artery. The correlation coefficients were -0-527 and -0-428, respectively, and in either case a test for zero correlations was significant (P less than 0-001). The possible changes in the haemodynamic and mechanical conditions associated with the variations of the anatomical pattern of the coronary arteries and their influence in the development of atherosclerosis are discussed. It is suggested that the length of the main left coronary artery is a congenital anatomical and possibly hereditary factor influencing the rate of development of atherosclerosis in the branches of the main left coronary artery.     

Double left anterior descending coronary artery arising from the left and right coronary arteries: a rare congenital coronary artery anomaly

Double left anterior descending coronary artery arising from the left and right coronary arteries is a very rare congenital coronary artery anomaly. In this report, we describe a patient with double left anterior descending coronary artery originating from the left and right coronary arteries. To the best of our knowledge, dual connection of the left anterior descending coronary artery to the left and right coronary arteries has been described in only five patients.     

Relation of left ventricular mass to geometry of the proximal coronary arteries in the dog

Proximal epicardial coronary artery luminal diameters were measured from silicone casts formed in situ in freshly excised hearts under a constant pressure of 100 mm Hg. Twenty-five coronary arteries from 15 normal dogs and 22 coronary arteries in 13 dogs with either chronic pressure or volume overload hypertrophy were studied. Mean left ventricular (LV) body weight ratios were 4.75 ± 1.01 g/kg in the normal dogs, 8.4 ± 1.7 g/kg in the pressure-overload dogs, and 6.2 ± 0.6 g/kg in the volume-overload dogs. The cross-sectional area of the left circumflex (LC) coronary artery was determined at 11 branch sites. The ratio of the area of the branches to the area of the parent vessel was 1.095 ± 0.105, indicating that the cross-sectional area after a branch point increased.

A poor correlation existed between LV mass and coronary artery diameter in both normal and hypertrophy groups for the LC (r = 0.44), the left anterior descending (LAD) (r = 0.63), and the combined LC and LAD (r = 0.52). The mean cross-sectional area of the combined LC and LAD was 0.12 cm² in the normal group and 0.15 cm² in the hypertrophy group; this increase was not statistically significant (p = 0.13). When the mean cross-sectional area of the combined vessels was adjusted for heart weight, there was a decrease in the cross-sectional area/100 g of myocardium in the hypertrophy group compared with the control group. These data demonstrate that coronary artery luminal diameter in the dog does not increase commensurately with the increase in mass associated with myocardial hypertrophy.     

Mid left anterior descending coronary artery originating from the right coronary artery

Dual connection of the left anterior descending coronary artery to the left and right coronary arteries is a very rare congenital anomaly. In this report we describe two cases in which the mid-position of the left anterior descending coronary artery is connected to the right coronary artery, one directly and the second by way of the infundibular artery. To the best of our knowledge, connection of the mid-position of the left anterior descending to the infundibular artery has not been previously described.     

Atresia of the proximal right coronary artery in association with coronary artery fistula.

A 2-year-old boy presented for evaluation of a systolic murmur. Echocardiogram demonstrated dilated left main and right coronary arteries. Selective injection of the left coronary artery confirmed dilation of the left main and anterior descending coronary arteries. The left anterior descending coronary artery subsequently filled the mid portion of the right coronary artery retrograde, which emptied into a blind fistula. The orifice of the right coronary artery was atretic, with no filling from the aortic root or the fistula.     

Echocardiographic visualization of coronary artery anatomy in the adult

In the light of technologic advances and the development of new imaging planes, the feasibility of two-dimensional echocardiographic visualization of coronary artery anatomy was reevaluated in the adult. Thirty-five subjects were studied using an ultrasonograph equipped with a 3.5 and 5.0 MHz annular array transducer, digital processing and cine loop review. There were 18 normal subjects and 17 patients with heart disease, including 9 patients with valvular, 5 patients with coronary, 2 patients with congenital and 1 patient with cardiomyopathic disease. The mean age was 47 +/- 18 years (range 17 to 79). Modifications of standard parasternal and apical views permitted high quality images of portions of each of the major epicardial vessels adequate for assessment of luminal diameter. The left main coronary artery was seen in 30 (86%) of the 35 subjects and its bifurcation was seen in 15. The left anterior descending coronary artery was seen in 30 subjects (mean length 3.9 +/- 2.3 cm, maximal length 7.5), the left circumflex artery in 11 (1.1 +/- 1.0, maximal 3.0) and the right coronary artery in 32 (5.6 +/- 2.6, maximal 12). Proximal and mid portions of the left anterior descending artery were seen in 23 and 11 subjects, respectively. The average proximal length visualized was 4.2 cm, and the average luminal diameter visualized was 4.9 mm. The average length of the mid left anterior descending coronary artery seen was 1.9 cm and the average luminal diameter seen was 4.6 mm. The proximal right coronary artery was seen in 17 subjects (average visualized length 2.7 cm and average diameter 3.1 mm).(ABSTRACT TRUNCATED AT 250 WORDS)     

Advantage of the cranial-right anterior oblique view in diagnosing mid left anterior descending and distal right coronary artery disease

The value of the cranial-right anterior oblique view in uncovering or improving the arteriographic visualization of lesions in the mid left anterior descending coronary artery, the origin of its diagonal and septal branches and of the distal branches of the right coronary artery was analyzed in 300 consecutive patients. The cranial-right anterior oblique view was compared with standard and other angled views. In the mid left anterior descending artery the view provided improved visualization over the other views in 80 percent of cases and uncovered lesions in 7 percent. In the septal arteries, the view improved visualization in more than 90 percent of cases and uncovered lesions in 26 percent. In the diagonal branches, the view improved visualization in nearly 75 percent of cases. In the distal right coronary artery there was improved visualization of the posterior descending and posterolateral branch arteries in more than 80 percent of cases. The cranial-right anterior oblique view was also the most advantageous view from a technical standpoint, yielding satisfactory exposure factors in obese and extremely heavy patients.     

Congenital atresia of left main coronary artery

We report a rare case of congenital atresia of left main coronary artery in an elderly male presenting with angina and positive stress thallium test. Coronary angiogram showed absence of left main coronary artery in the left aortic sinus. Collaterals from right coronary artery supplied left anterior descending artery and left circumflex artery territories. Despite collaterals, the left anterior descending and left circumflex arteries were rudimentary. Poor size of left-sided arteries precluded any surgical revascularization which is the treatment of choice in this rare entity.     

Quantitative study on the size of coronary artery supplying areas postmortem.

The relative amount of myocardium perfused by the three large coronary arteries was determined in 171 human hearts postmortem. Roentgenograms of transverse serial sections of the ventricular myocardium enabled planimetrical measurements. With little variation, an average of 41.5 per cent of the entire ventricular myocardium was supplied by the left descending coronary artery. Both left branches supplied an average of 63.8 per cent and the right coronary artery supplied 36.2 per cent of the myocardium. The size of supplying areas, in particular that of the right coronary artery and the left circumflex branch, was mainly dependent upon the coronary artery types. As a rule cardiac hypertrophy did not influence the size of coronary supplying areas as much as did the coronary artery types. Only very few hearts revealed that the myocardium was supplied to a greater extent by the right coronary artery than by the left (5.3 per cent). There is a close relationship between the size of the myocardial supplying area and the lumen of the corresponding coronary artery.     

Dual left anterior descending coronary artery: surgical revascularization in 4 patients

Dual left anterior descending artery (or dual anterior interventricular artery) is a rare coronary anomaly. It is important to know the anatomic variants of this anomaly in patients with coronary artery disease who are undergoing either surgical myocardial revascularization or coronary angioplasty. We report the cases of 4 patients who had anatomic variants of dual left anterior descending coronary artery. These patients had developed coronary artery disease in the long or the short left anterior descending artery, or in both. The long left anterior descending artery was diseased in 1 patient, and the short left anterior descending artery was diseased in another In the 3rd and 4th patients, both the long and the short arteries were atherosclerotic and had developed severe stenosis. All 4 patients underwent successful myocardial revascularization. There was no electrocardiographic evidence of perioperative myocardial infarction. All patients were asymptomatic during the follow-up period, which ranged from 3 months to 1.5 years. Angiographers and surgeons alike must be aware of the variants of dual left anterior descending coronary artery, so that the diseased vessels can be correctly identified even if 1 of the dual arteries is 100% occluded.     

Triple origin of left coronary arteries from right coronary artery: Unusual case of single coronary artery

A rare case of coronary anomaly is presented: all of the coronary arteries originated from a single ostium located in the right coronary cusp. No clinical evidence of coronary pathology was recognized until the age of 57 years when the patient was found to have coronary obstructive disease. The single coronary artery had a main branch corresponding to the usual dominant right coronary artery. Three other branches separated from this and vascularized the areas normally receiving the circumflex and ramus medianus, the left anterior descending, and a large septal branch.     

Impact of compensatory enlargement of atherosclerotic coronary arteries on angiographic assessment of coronary artery disease

To determine whether compensatory enlargement of atherosclerotic coronary arteries occurs and to what degree it affects the angiographic assessment of coronary artery disease, we performed postmortem coronary angiography of 30 human hearts with suspected coronary artery disease and studied 70 histologic cross sections of the proximal left anterior descending artery and proximal right coronary artery. Angiographic and morphometric analyses of 50 stenoses in proximal and middle sections of the left anterior descending artery, right coronary artery, and left circumflex artery were performed. The control group of 10 human hearts without suspected coronary artery disease was evaluated in the same way. For this purpose, coronary arteries were filled with a methylmethacrylic radiopaque resin at a pressure of 100 mm Hg and closely embedded in a methylmethacrylic resin by use of which shrinkage and mechanical artifacts could be avoided. The area circumscribed by the internal elastic lamina was taken as a measure of the area of the arterial lumen if no plaque had been present. The angiographic and corresponding morphometric degree of stenosis was assessed. A significant correlation (r = 0.85, p less than or equal to 0.0001) was found between the internal elastic lamina area and the area of the plaque (lesion area), suggesting that coronary arteries may enlarge as lesion area increases. With the morphometric degree of stenosis, the expected anatomic diminution of the coronary artery was abolished (r = 0.79, p less than or equal to 0.0001), indicating compensatory enlargement in atherosclerotic segments. Accordingly, the degree of stenosis assessed from in vitro angiograms was underestimated. Compensatory coronary enlargement of the stenotic segment was the main reason for angiographic underestimation. The underestimation factor of up to 3.50 for very mild stenoses decreased to 1.37 at an angiographic degree of 50% area stenosis and 30% diameter stenosis.(ABSTRACT TRUNCATED AT 250 WORDS)     

Angiographic estimation of relative coronary artery flow based on terminal branching patterns.

Angiographically "terminal" coronary arterial branches were counted in 100 normal coronary cineangiograms to investigate the possibility that three left ventricular wall regions might be defined by identifying patterns of arterial inflow. An average of 45% of the terminal branches were counted in the anterior region supplied by the anterior descending coronary artery; 25% were counted in the lateral region supplied by diagonal and obtuse marginal arterieistal circumflex and distal right arteries. Based upon the hypothesis that blood flow through an artery is directly proportional to the number of small branches into which it ramifies, this approach affords an estimate of the relative contribution by individual coronary arteries to total left ventricular perfusion. This concept could prove useful in defining a quantitative grading system of coronary arterial inflow obstruction.     

Patterns of coronary artery movement and the development of coronary atherosclerosis.

Mechanical stress in coronary arteries has been postulated to cause endothelial injury and atherosclerotic lesions, but the relationship between the pattern of coronary artery movement (CAM) and lesion severity is not known. In the present study CAM was classified into 10 patterns, which were grouped into 3 classes: (1) bend type = coronary artery flexes into a curve; (2) compression type = segmental length is shortened without vertical deviation of the artery; (3) displacement type = location of the coronary artery shifts without change of segmental length or shape. Assessment of CAM was made for 6 segments from the left anterior descending artery and 3-5 segments from the left circumflex artery, and in total 673 segments were analyzed. Coronary arterial segments with the compression type had a significantly higher percent stenosis than those without it (Compression 57.9+/-29.4 % vs Bend 7.9+/-19.0 %, Displacement 4.3+/-13.0 %; p<0.00001). The compression type was seen frequently in the proximal and mid left anterior descending artery, ostial diagonal branch, obtuse marginal branch and mid left circumflex artery. The critical CAM (eg, compression pattern) may be an important mechanical stress inducing coronary atherosclerosis.     

Clinical utility of two-dimensional magnetic resonance angiography in detecting coronary artery disease

AIMS: The accuracy of magnetic resonance angiography in detectingproximal coronary artery stenoses is unclear. We postulatedthat fast magnetic resonance angiography is capable of (1) imagingproximal coronary arteries, and (2) detecting stenoses of 50%of their luminal diameter. METHODS AND RESULTS: Thirty-five patients, referred for analysis of angina pectoris,underwent both conventional angiography and magnetic resonanceangiography of coronary arteries. A fast k-space segmented gradient-echotechnique was used during breath-holds. Two observers, blindedto the results of conventional angiography, independently analysedthe magnetic resonance studies for (1) length of visualizedsegments, and (2) presence of signal voids indicative of stenoses.From 140 proximal arteries, 15 (11%) were excluded because ofincomplete imaging or degraded image quality. Mean length ofthe visualized segments was 9±4 mm for the left main,62±16 mm for the left anterior descending, 21±9mm for the left circumflex and 89±32 mm for the rightcoronary artery. Sensitivity for detecting 50% luminal diameterstenoses was 0·00 for the left circumflex, 0·53for the left anterior descending coronary artery, 0·71for the RCA and 1·00 for the left main artery. Specificityvaried from 0·73 for the left anterior descending coronaryartery to 0·96 for the left circumflex. Inter-observeragreement was 0·90. CONCLUSION: Thus, segmented magnetic resonance angiography is capable ofnon-invasive imaging of proximal coronary anatomy. Its goodaccuracy in detecting left main coronary artery disease, intermediateaccuracy in detecting right coronary artery and left anteriordescending coronary artery stenoses, and low accuracy in detectingleft circumflex lesions fit within a range of sensitivitiesand specificities found by others. Further technical advancesare necessary to make the technique clinically robust.     

Double left anterior descending artery originating from the left and right coronary artery: A rare coronary artery anomaly

A case of double left anterior descending coronary artery is presented. The double artery originated from the left main stem and the right coronary artery. There were no stenoses on these two arteries. This anomaly of coronary arteries seems to be very rare. © 1993 Wiiey-Liss, Inc.