Entire Coronary Tree Research Articles

Significance of coronary artery tone assessed by coronary responses to ergonovine and nitrate.

The coronary artery response to ergonovine (EM) and nitrate of the proximal, middle and distal segments of the three major coronary artery branches and the main trunk was quantified in 67 patients without coronary spasm and in 69 patients with coronary spasm without significant organic stenosis. The changes in control diameter and diameter after EM administration compared to diameter after nitrate were used as the index of coronary artery tone. EM increased coronary artery tone regardless of the occurrence of coronary spasm (p less than 0.01). In all segments, basal coronary artery tone was greater in patients with spasm than in patients without spasm (p less than 0.01) in a way similar to the coronary responses to EM (p less than 0.01). In patients with spasm, both coronary artery tone after EM and basal coronary tone were greater in the spastic segments than in the nonspastic segments (p less than 0.01), which were greater than those in patients without spasm (p less than 0.01). Our data suggest that patients with spasm may have increased basal tone, and that coronary artery spasm may be based on increased coronary tone. Clinically, evaluation of the basal tone and response to EM in the entire coronary artery tree may be useful for predicting the presence of coronary artery spasm.

Angiographic assessment of the culprit coronary artery lesion before acute myocardial infarction

Serial angiographic studies of patients with myocardial infarction and unstable angina suggest that the culprit plaque underlying a thrombus need not have produced severe luminal obstruction before onset of the event. An atherosclerotic coronary artery lesion can, therefore, have 2 important characteristics. First, it may be obstructive. Second, it may be “vulnerable” in that it has the potential to become thrombogenic if exposed to the appropriate triggering stimulus. A lesion need not be obstructive to become thrombogenic, nor do all obstructive lesions have thrombogenic potential. The cause of an infarction may thus be rupture of a nonobstructive plaque leading to occlusive thrombus formation. Because it may be difficult to predict the site of a subsequent occlusion from a coronary angiogram, coronary bypass surgery or angioplasty directed only at discernible stenotic lesions may not be effective for preventing subsequent myocardial infarctions. Appropriate therapy may need to be directed at the entire coronary tree. Such therapy might include cholesterol lowering, β blockade and aspirin.

Significance of coronary artery tone in patients with vasospastic angina

To investigate the relation between basal coronary artery diameter and development of coronary artery spasm, the diameters of the proximal, middle and distal segments of the three major coronary artery branches, together with that of the left main trunk, were measured on a control angiogram and after ergonovine and nitrate administration in 30 patients with vasospastic angina without significant organic stenosis, and in 35 patients without ischemic heart disease. The percent change in coronary diameter after ergonovine and nitrate administration compared with the control diameter was used as an index of coronary vasoreactivity.In patients with vasospastic angina, coronary artery responses to both ergonovine and nitrate were greater in the spastic segments than in the other segments (p < 0.05), and those of the coronary arteries without spasm were greater than those of the coronary arteries in patients without ischemic heart disease (p < 0.01). There were no significant differences between the coronary artery diameters in the two groups after nitrate administration, and the control diameters were less in patients with vasospastic angina than in patients without ischemic heart disease.These observations indicate that a coronary vasomotion disorder, which involves increased basal coronary artery tone and hypersensitivity to vasoconstrictive stimuli, not only at a localized segment but also in the entire coronary artery tree, is present in patients with vasospastic angina. Clinically, evaluation of basal coronary artery tone may be useful for predicting the occurrence and location of coronary artery spasm.

Evaluation of coronary anatomy using high-speed volumetric computed tomographic scanning

Although coronary angiography involves minimal risk, it is sufficiently invasive that symptoms suggestive of myocardial ischemia are usually needed before the procedure is indicated, and presymptomatic patients in an at-risk group generally do not undergo catheterization. A practical method for obtaining coronary anatomy is computed tomographic (CT) scanning of contrast-filled coronary arteries. To visualize the epicardial coronary branches, a 3-dimensional (volume) CT image must be generated that contains the entire coronary tree, and the volume must be scanned fast enough to minimize image blurring and distortion due to cardiac motion. These features are available with the dynamic spatial reconstructor (DSR). In this report, we describe our initial use of the DSR to evaluate coronary anatomy from a single selective contrast medium injection into the left coronary artery. The DSR is a prototype instrument (Fig. 1) capable of scanning a 3-dimensional volume 21.5 cm in length and in diameter in 0.01 second and at a rate of 60 times/s. It contains 14 x-ray sources with 14 corresponding video based imaging chains. The x-ray tubes and image chains are mounted on a rotating turret (15 rpm) and are pulsed sequentially to provide 12-degree increments in viewing angle around the semicircular scanning arc. Detailed description of the DSR has been provided in previous studies. 1–3

Status of the coronary arteries in the nephrotic syndrome: Analysis of 20 necropsy patients aged 15 to 35 years to determine if coronary atherosclerosis is accelerated

This report describes the status of the major extramural (epicardial) coronary arteries in 20 patients (average age = 24 years) with the nephrotic syndrome (from systemic lupus erythematosus in 13 patients, diabetes mellitus in four and chronic idiopathic glomerulonephritis in three), and compares the clinical and morphologic observations to those in 14 control subjects (average age = 29 years). Both patients with the nephrotic syndrome and control subjects ranged in age from 15 to 39 years. The 20 patients with the nephrotic syndrome had significantly more coronary luminal narrowing by atherosclerotic plaques than did the control subjects. The lumens of one or more of the four major coronary arteries were narrowed >75 per cent in cross-sectional area in eight (40 per cent) of the 20 nephrotic patients and in none of the 14 control subjects. This difference in degree of coronary disease was even more striking when the per cent of narrowing in the entire coronary tree was examined: of the 290.5 cm of coronary artery examined in the 20 nephrotic patients, the lumen in 88 cm (30 per cent) was >50 per cent narrowed in cross-sectional area, whereas of 288 cm of coronary artery examined in the 14 control subjects, the lumen in only 5.5 cm (2 per cent) was narrowed to this degree. Although the cause of the accelerated coronary atherosclerosis in our nephrotic patients is uncertain, hypercholesterolemia, systemic hypertension, corticosteroid therapy and increased clotting tendencies probably all contributed to this acceleration.

The frequency and significance of coronary arterial thrombi and other observations in fatal acute myocardial infarction: A study of 107 necropsy patients

Observations made from histologie study of the entire extramural coronary arterial tree are described in 107 patients who died of acute ischemie heart disease: seventy-four had transmural left ventricular myocardial infarction, nine had necrosis limited to the inner one half of the left ventricular myocardium (acute subendocardial infarcts) and twenty-four died suddenly (less than six hours from onset of symptoms of myocardial ischemia) without histologically detectable myocardial necrosis. Old atherosclerotic plaquing was diffuse and extensive in the extramural coronary arteries in 104 of the 107 patients. The lumens of at least two of the three major extramural coronary arteries (right, left anterior descending and left circumflex) were narrowed more than 75 per cent by old atherosclerotic plaques in 101 of the 107 patients.Coronary arterial thrombi were found in forty (54 per cent) of the seventy-four patients with transmural necrosis, in none of the nine with only subendocardial necrosis and in two (8 per cent) of the twenty-four who died suddenly. In thirty-seven of the forty-two patients with antemortem coronary arterial clots the lumen of the vessel containing the thrombus was already narrowed more than 75 per cent by old atherosclerotic plaques at or distal to the thrombus. The infrequency of coronary thrombi in patients who died of acute cardiovascular collapse without myocardial necrosis, in those in whom necrosis was limited to the subendocardium, in those who died without cardiogenic shock or congestive cardiac failure, and their occurrence at, or proximal to, sites already severely narrowed by old atherosclerotic plaques suggest that coronary thrombi are consequences rather than causes of acute myocardial infarction. The occurrence of components of thrombi, i.e., fibrin and platelets, in old atherosclerotic plaques and the finding of components of old atherosclerotic plaques, i.e., foam cells, cholesterol clefts, pultaceous debris and calcific deposits, in known thrombi (for example, those located in the left atrium of patients with mitral stenosis) strongly suggest, however, that old atherosclerotic plaques are derived, at least in part, from organization of thrombi.

Physiologic Evaluation of Angina Pectoris

Electrocardiographic and ballistocardiographic observations have been the only objective methods easily available for assessment of the state of the coronary circulation. As has been pointed out, however, these methods give only indirect information concerning the hemodynamic status and functional adequacy of the coronary circulation. The extensive pathologic studies of the coronary arteries in angina pectoris”2 have demonstrated that these vessels seldom show a single vascular disturbance, but more often, demonstrate diffuse involvement of the entire coronary vascular tree leading to increased large vessel resistance to blood flow. Physiological principles have been applied to the understanding of other cardiac problems, particularly valvular, congenital and constrictive heart disease and congestive heart failure. They have led to the development of objective hemodynamic methods of evaluation which would appear to be of value for the coronary circulation as well. We have attempted such an approach. Our findings are based on a correlative clinical, electrocardiographic and cardiac catheterization study of 43 patients. Coronary sinus catheterization was performed and coronary blood flow measured by the nitrous oxide technique’ as modified by Goodale and Hackel.4 Diastolic coronary vascular resistance was calculated.5 The group of 43 patients was subdivided as follows: Group 1 was the normal group, composed of 10 patients with negative histories, physical examinations and resting and post-exercise electrocardiograms. Group 2 was the abnormal group, composed of 23 patIents with typical angina pectoris and positive electrocardiographic examinations. Group 3 was designated the unknown group, composed of 10 patients, all of whom complained of atypical chest pain, and In whom the resting and exercise electrocardiograms were negative or equivocal. Three of these patients had left ventricular hypertrophy secondary to aortlc valve disease. The open columns in Figure 1 summarize the results of resting studies performed in normals, in patients with coronary artery disease and in those with increased left ventricular work. Coronary flow was essentially the same in all three groups; in the coronary group it was actually 19 per cent above normal. Diastolic coronary vascular resistance, which encompasses coronary inflow time as well as perfusion pressure, is perhaps the most useful index of the cross-sectional area of the coronary vascular bed. Again, no difference was found among these groups. In a recent report evaluating internal mammary ligation for angina pectoris, nitrous oxide flows were performed at rest. The authors found no difference in values before and after ligation, and therefore, concluded

Interventricular Septal Rupture as a Result of Myocardial Infarction with Survival for 18 Months

Rupture of the heart has usually been considered to be immediately fatal. Numerous case studies refute that impression. Hymen’ reported an instance of a young Negro who was able to run nearly a quarter of a mile with a knife blade sticking through his chest and piercing his left ventricle. Other observers have reported similar experiences. Vaughan,’ Constantine,’ and Hesse4 have collected many such cases from the literature. With present surgical skill, the heart has lent itself to even more dramatic recoveries. In this traumatic group, the uninjured portion of muscle is usually normal and has an abundant reserve. Rupture as result of cardiovascular pathology does not offer the same hopefulness. The entire coronary tree is likely to be diseased with resulting diffuse myocardial damage. The reserve of the heart is therefore at a minimum so that surgery, even though immediate and heroic, is unable to overcome this absence of support. This lack of surgical aid does not mean such perforations need invariably be fatal. With the employment of anticoagulants, improved hospital f acilities, a broader understanding of the mechanism and control of heart failure, and measures to control shock, medical management can salvage a number of cases which ordinarly would be considered hopeless. Rupture of the heart following an infarction is not a rarity. Beresford and Earl’ reported a high incidence of such ruptures in mentally defective patients. They ascribe such occurrences to the fact that uch patients are less aware of pain and therefore exert themselves unduly without proper restrictions. The ruptures were most likely to occur between the third and 12th day when the area of infarction was softest. Most of such ruptures are through the wall into the pericardium. Perforations of the septum are more rare. The septum has a better collateral circulation and is therefore less susceptible to complete occlusion. When such a perforation does occur, it indicates extensive coronary disease.6’Gross8 in his studies of coronary arteries by means of injection, noted the rich anastomosis of arterial supply in this region. With a septal perforation, branches of both the anterior and posterior descending coronary arteries are likely to be involved. Furthermore, the relative freedom of the septum from marked changes in pressures applied to its sides, tends to preserve its integrity.