Coronary artery abnormalities after Kawasaki disease in an adult: depiction at whole heart coronary magnetic resonance angiography

Whole heart coronary magnetic resonance angiography (MRA) was performed in a 57-year-old man with a provisional diagnosis coronary artery aneurysm due to Kawasaki disease. MRA revealed aneurysms in the left anterior descending artery and the left circumflex artery. It also revealed stenosis in the left anterior descending artery and occlusion in the right coronary artery with a collateral vessel connecting between the proximal and distal sites of the occlusion.     

Relation of coronary arterial occlusion pressure during percutaneous transluminal coronary angioplasty to presence of collaterals

To investigate the relation of the gradient across a coronary artery stenosis and the pressure distal to the stenosis after proximal occlusion during percutaneous transluminal coronary angioplasty to the amount of angiographically estimated collateral circulation, 63 patients (55 men, 8 women) were studied. All patients had 1-vessel disease (54 left anterior descending, 8 right coronary artery and 1 circumflex coronary artery). All patients had documented ischemia, and angioplasty was carried out within 4 weeks after the initial angiogram. The patients were separated into 4 groups: 0 = no collaterals (35 patients), +1 = just visible collaterals (8 patients), +2 = collaterals without reaching the contralateral vessel (10 patients), and +3 = filling of the contralateral vessel (10 patients). There was no difference in age among the 4 groups. There was a significant negative relation of the gradient vs the extent of collateral circulation, although the degree of stenosis increased significantly from group 0 to group +3. There was a significant positive relation of the occlusion pressure (in absolute terms and in percent of the proximal systolic pressure) vs the extent of collateral circulation. There was a significantly smaller change of the occlusion pressure vs the distal pressure before occlusion if good collaterals were present. The occlusion pressure remained constant during 1 occlusion up to 40 seconds and was reproducible in 3 successive occlusions. In conclusion, the pressure distal to a coronary artery stenosis is mainly dependent on the severity of the stenosis and on the collateral flow. If anterograde flow is eliminated by proximal occlusion the distal pressure is only dependent on the extent of collateral circulation.     

Severity of single-vessel coronary arterial stenosis and duration of angina as determinants of recruitable collateral vessels during balloon angioplasty occlusion

To determine the factors that influence the presence of collateral vessels during coronary occlusion, we performed standardized contrast injection of the contralateral coronary artery in 58 consecutive patients, without previous myocardial infarction, undergoing percutaneous transluminal coronary angioplasty for 1-vessel disease (left anterior descending artery in 45, right coronary artery: in 10 and left circumflex artery in 3). The presence of collateral vessels during coronary occlusion, defined as partial or complete epicardial opacification by collateral vessels of the vessel dilated, was related to clinical, angiographic and electrocardiographic parameters. The angiographic appearance of collateral vessels during balloon inflation showed a weak, although statistically significant, correlation to the percent diameter stenosis before angioplasty (r = 0.28; p = 0.03) and the duration of angina (r = 0.37; p = 0.004). By combining lesion severity with the duration of angina, collateral vessels during coronary occlusion were particularly related to a lesion severity greater than or equal to 70% and duration of angina greater than or equal to 3 months (p less than 0.001). Furthermore, the presence of collateral vessels was associated with an absence of ST-segment shift (greater than or equal to 1 mm) during 1 minute of coronary occlusion (p less than 0.001).     

Collateral coronary circulation in the absence of obstructive coronary artery disease

The presence of collateral coronary circulation almost always accounts for significant obstructive coronary artery disease and its development remains unclear. We present two cases wherein there was a large collateral artery in a patient with angiographically normal coronary arteries. In both cases, the vessel ran in the atrioventricular groove, between the distal right coronary artery and the circumflex artery. We believe that this vessel is of congenital origin and after reviewing the literature we describe the angiographic features that distinguish such a vessel from collaterals that are secondary to coronary stenosis or hypoxia.     

Relationship between coronary collateral growth in the dog and ischemic bed size

Summary Two models of gradual coronary occlusion (Ameroid method) were compared in this study: 3 months circumflex and 3 months right coronary occlusion. Following coronary occlusion, the collaterals developed in intact, normally active dogs. The collateral flows were assessed in an isolated heart preparation. The results indicated a pattern for collateral development. Collateral flow was directed primarily toward the left heart with circumflex occlusion, and toward the right heart with right occlusion. Although dominant collateralization was via epicardial collaterals, intramyocardial septal collaterals strongly participated in growth development of both models. Collateral growth to the circumflex with circumflex occlusion was 6.54 fold greater than collateral growth to the right coronary artery with right occlusion. The data suggest a relationship between collateral growth and ischemic bed size.This work was supported by the American Heart Association, and by USPHS grant HL-24323.     

The sword of Damocles: an illustrative example of the life-saving effect of the collateral circulation

There is an ongoing debate on the effective importance of the collateral network, especially in the current era, where most patients with significant coronary artery disease are revascularized, be it percutaneously or surgically; thus, people may question a significant benefit of the coronary collateral circulation. However, the presented 61-year-old male patient demonstrates an unambiguous situation of a life-saving effect of the collateral circulation. The patient presented without any angina symptoms and with only mild shortness of breath on moderate to severe exertion. A subsequent angiography revealed a complete chronic occlusion of the main coronary artery. The entire left coronary system was provided by well-developed right to left collaterals. Additionally, the patient had an 80-90% stenosis of his mid-right coronary artery (RCA). The entire blood supply to the heart had to pass this lesion to provide the RCA area and also the left anterior descending and left circumflex areas via collaterals. This extreme example illustrates the potentially lifesaving effect of the coronary collateral circulation. Obviously, the entire myocardium can in some cases be perfused entirely via one critically stenosed vessel.     

Left main coronary artery occlusion with preserved left ventricular function: a report of three cases

Three patients with angina pectoris are reported in whom occlusion of the left main coronary artery was found at coronary arteriography. In these three patients left ventricular function was well preserved. In all three the right coronary artery was dominant and there were prominent epicardial and septal collateral vessels to the territories normally supplied by the left anterior descending and circumflex arteries. It seems reasonable to suggest that this coronary artery anatomy and collateral vessel formation accounted for the preservation of the left ventricular myocardium in these patients.     

Left main coronary artery occlusion with preserved left ventricular function: a report of three cases.

Three patients with angina pectoris are reported in whom occlusion of the left main coronary artery was found at coronary arteriography. In these three patients left ventricular function was well preserved. In all three the right coronary artery was dominant and there were prominent epicardial and septal collateral vessels to the territories normally supplied by the left anterior descending and circumflex arteries. It seems reasonable to suggest that this coronary artery anatomy and collateral vessel formation accounted for the preservation of the left ventricular myocardium in these patients.     

Total occlusion of the left main coronary artery: The Coronary Artery Surgery Study (CASS) experience

Total occlusion of the left main coronary artery was confirmed on review of the coronary angiograms in 12 (0.06 percent) of the 20,197 patients entered into the Coronary Artery Surgery Study (CASS) before coronary arterial surgery. Clinical features alone could not distinguish the patients with total occlusion of the left main coronary artery from those enrolled in the CASS with subtotal stenosis of this vessel. The right coronary artery had a stenosis greater than or equal to 70 percent of luminal diameter in 7 of the 12 patients. Collateral flow to the left coronary artery was defined as “substantial” or “limited” based on the presence or absence of clear visualization of the main channel of either the left anterior descending or left circumflex coronary artery during coronary angiography. Of the eight patients with “substantial” collateral flow, one (13 percent) had an aneurysmal or dyskinetic left ventricular wall segment, whereas all (100 percent) of the three patients with “limited” collateral flow had dyskinesia or an aneurysm (p < 0.05). Seven patients underwent coronary bypass graft surgery; 6 (86 percent) of these patients were living at their most recent follow-up, a mean of 46 months after entry into the CASS. Two of these patients continued to have angina pectoris. Five patients did not undergo coronary bypass grafting and 2 (40 percent) were still alive at their most recent follow-up, a mean of 45 months after entry into the CASS. One of these patients had angina pectoris. The difference in survival between the medical and surgical groups was not statistically significant.

This study indicates that patients with total occlusion of the left main coronary artery are uncommon and cannot be distinguished by presenting features alone from patients having subtotal stenosis of the left main coronary artery. “Substantial” coronary collateral blood flow is associated with better left ventricular wall motion than is “limited” collateral flow. Prolonged survival and lessening of symptoms may occur after coronary bypass grafting although long-term survival is possible without it.     

Collateral conductance changes during a brief coronary occlusion in awake dogs

Function of the coronary collateral circulation during the course of a single abrupt coronary occlusion was evaluated in awake dogs instrumented over the long term. Studies were performed approximately 2 weeks after collateral development had been stimulated in the dogs by partial stenosis of the proximal left circumflex coronary artery. The pressure drop from the central aorta to the distal circumflex coronary artery was measured continuously. Under control conditions and at 30 sec and 4 min of a single abrupt complete circumflex occlusion, myocardial blood flow was determined by a radioactive microsphere technique. Coronary collateral conductance was calculated as mean collateral blood flow divided by the mean drop in pressure. The following was noted in dogs that developed collateral vessels: during the coronary occlusion, mean distal circumflex coronary pressure increased from 42 +/- 9 to 49 +/- 10 mm Hg (p less than or equal to .01); mean collateral flow increased from 0.78 +/- 0.30 to 0.84 +/- 0.33 ml/min/g (p less than or equal to .05); the endocardial/epicardial flow ratio increased from 0.77 +/- 0.36 to 1.04 +/- 0.25 (p less than or equal to .01); and the coronary collateral conductance increased significantly from 0.017 +/- 0.017 to 0.021 +/- 0.021 (ml/min/g)/mm Hg (p less than or equal to .005). These data suggest that during a brief occlusion of a major coronary artery, immature coronary collateral channels do not reach maximal function immediately after the occlusion. Rather, coronary collateral conductance increases with time and may be associated with improved transmural perfusion of the myocardium.     

Effect of stenosed and occluded coronary arteries on immediate and late myocardial uptake of thallium-201.

Exercise and redistribution myocardial scintigraphy using thallium-201 was compared with the left ventricular angiogram and with the presence of stenosis or occlusion of coronary arteries on angiography. Irreversible scintigraphic defects representing areas of myocardial infarction were found in all patients with occlusion of the left anterior descending artery but nearly one-third of patients with stenosis of that artery also showed evidence of infarction. For the right coronary or circumflex arteries the incidence of infarction was 82% with vessel occlusion and 57% with vessel stenosis. Of abnormally contracting segments on the left ventricular angiogram, 95% showed irreversible scintigraphic defects but 33% of normally contracting segments supplied by a diseased artery also showed this. Myocardial infarction is not uncommon in patients with angina even in the absence of coronary occlusion. The incidence is underestimated by the left ventricular angiogram. These findings are of importance in the assessment of patients with coronary disease and their evaluation before coronary artery surgery.     

Value of lead V4R for recognition of the infarct coronary artery in acute inferior myocardial infarction

In 84 patients with an acute inferior wall myocardial infarction (MI) admitted within 10 hours after the onset of chest pain, a right precordial lead V4R electrocardiogram was recorded in addition to the standard 12-lead electrocardiogram. The presence or absence of ST-segment elevation in lead V4R was correlated with results of coronary angiography performed 2 to 26 weeks (mean 10) after MI. Patients were classified into 3 groups: (1) those with a critical stenosis or occlusion proximal to the first right ventricular (RV) branch (27 patients); (2) those with stenosis distal to the right ventricular branch of the right coronary artery (36 patients); and (3) those with stenosis in the left circumflex coronary artery (21 patients). The presence of ST-segment elevation greater than or equal to 1 mm in lead V4R has a sensitivity of 100% and a specificity of 87% for occlusion of the right coronary artery above the first RV branch; the predictive accuracy is 92%. Seven of 36 patients with a distal occlusion of the right coronary artery showed ST-segment elevation of 1 mm or more in lead V4R . The absence of ST-segment elevation greater than or equal to 1 mm in lead V4R excluded proximal occlusion of the right coronary artery. ST-segment elevation in lead V4R was not seen either in 29 of 36 patients with a distal occlusion of the right coronary artery or in all patients with an occlusion of the left circumflex artery. Recording of lead V4R within 10 hours after onset of acute inferior wall MI can give information rapidly about the vessel responsible for MI.(ABSTRACT TRUNCATED AT 250 WORDS)     

Importance of myocardial ischemia for coronary collateral development in conscious dogs

The purpose of this study was to evaluate the effects of myocardial ischemia on the development of collateral circulation. Thirteen conscious dogs were instrumented for serial measurements of subendocardial segment length in the area perfused by the left circumflex coronary artery, left circumflex coronary artery flow and left ventricular pressure. In 6 dogs (group A), 1 min left circumflex coronary artery occlusions were carried out at 30 min intervals. When the 442nd 1 min left circumflex coronary artery occlusion produced a reduction in segment shortening and a significant reactive hyperemia, the occlusion time was increased to 2 min. In the remaining 7 dogs (group B), 2 min left circumflex coronary artery occlusions were conducted hourly. In group A, following 451 +/- 201 (SD) min of total occlusion time with the mixture of 1 and 2 min left circumflex coronary artery occlusions (43 +/- 18 days) a left circumflex coronary artery occlusion produced no reduction in segment shortening and negligible reactive hyperemia. By contrast, in group B, 218 +/- 99 min of total occlusion time (18 +/- 8 days) was required to develop adequate collateral circulation. The relative contribution of the first and second 1 min of left circumflex coronary artery occlusion to the collateral development was mathematically evaluated. This analysis indicated that the second 1 min of left circumflex coronary artery occlusion is 4.43-fold more effective than the first 1 min of occlusion in terms of the collateral induction. We concluded that severe myocardial ischemia plays an important role in the development of collateral circulation.     

Coronary steal in four models of single or multiple vessel obstruction in dogs

Two types of coronary steal (subendocardial to subepicardial; collateral dependent to noncollateral dependent) were examined in four models of single or multiple vessel obstruction In 32 anesthetized dogs with controlled heart rate and aortic blood pressure. Different degrees of vasodilation were produced by use of the selective coronary arteriolar dilator, chromonar. Subendocardial to subepicardial steal was studied in two models of stenosis, mild (50 percent decrease in reactive hyperemia) and severe (93 percent decrease In reactive hyperemia). During mild left circumflex arterial stenosis, chromonar produced an Increase In poststenotic blood flow primarily In the subeptoardtum with only minimal increases in the subendocardium. The Ischemic $\text{endocardial}\text{epicardial}$ flow ratio decreased significantly. During severe left circumflex stenosis, chromonar produced an increase in poststenotic subepicardial flow whereas subendocardial flow decreased. The ischemic $\text{endocardial}\text{epicardial}$ flow ratio also decreased significantly. Changes In $\text{endocardial}\text{epicardial}$ flow ratio correlated closely with distal diastolic perfusion pressure in both models of stenosis (r = 0.84, p <0.001).Collateral-dependent to noncollateral-dependent steal was studied in two models of total left anterior descending coronary arterial occlusion. During distal occlusion of this artery, collateral blood flow decreased significantly only during chromonar-lnduced maximal vasodilation, whereas mild vasodilation produced a significant decrease in collateral flow when a proximal left circumflex stenosis was present in addition to occlusion of the left anterior descending artery. These results demonstrate that mild to maximal coronary vasodilation produces coronary steal in different models of single or multiple vessel disease In the absence of changes in aortic pressure and heart rate. Decreases in perfusion pressure distal to a stenosis or at the origin of collateral vessels are responsible for the two types of coronary steal.     

Manifestation of an anomalous origin of the right coronary artery from the pulmonary artery after development of significant coronary disease

We describe a 71-year-old man with a history of a small posterior myocardial infarction. Angiographically he showed a coronary artery disease with major proximal stenosis of both branches of the left coronary artery and an occlusion of the marginal branch of the circumflex artery (infarct-related vessel). As an unexpected finding, an anomalous origin of the right coronary artery from the pulmonary artery was also found. This rare condition may cause development of ischemia with potentially lethal complications as a result of coronary steal phenomenon. Surgical treatment is, therefore, indicated even in asymptomatic patients with this anomaly. Possible surgical procedures and there indications are discussed.     

Percutaneous transluminal coronary angioplasty of anomalous left circumflex coronary artery

We present our experience of percutaneous transluminal coronary angioplasty in two patients with an anomalous left circumflex coronary artery with severe stenosis. In the first case, the anomalous vessel originated from the first portion of the right coronary artery, and in the second case it originated from the right sinus of Valsalva. Cannulating the anomalous vessel with the guiding catheter can be difficult. The right Judkins-type catheter, with a posteriorly directed tip, is the most appropriate catheter for cannulating the anomalous circumflex artery when the vessel originates from the first portion of the right coronary artery, and the left Amplatz-type 1 is most appropriate when the vessel originates from the right sinus of Valsalva.     

Electrocardiographic differentiation between right coronary and left circumflex coronary arterial occlusion in isolated inferior wall myocardial infarction

The presence of atrioventricular block and ST segment elevation in lead V4R accurately predicts right coronary artery occlusion in patients with inferior wall myocardial infarction. However, these electrocardiographic signs are absent in the majority of patients with inferior myocardial infarction. We studied ST segment elevation in leads II and III, ST segment in lead I and T wave polarity in lead V4R in order to differentiate between right coronary artery and left circumflex coronary artery occlusions in 104 patients with inferior myocardial infarction who subsequently underwent coronary angiography. The ST segment elevation was greater in lead III than in lead II when the right coronary artery was the culprit vessel and vice versa when the left circumflex was the culprit vessel (p < 0.001). An upright T wave in lead V4R and ST segment depression in lead I was common when the right coronary artery was the culprit vessel and not seen with left circumflex occlusion (p < 0.001). ST segment elevation in lead III was higher than in lead II with a sensitivity of 99 percent and a specificity of 100 percent for diagnosing right coronary artery as the culprit vessel. ST segment elevation in lead II was higher than in lead III with a sensitivity of 93 percent and a specificity of 100 percent in identifying the left circumflex as the culprit vessel. Thus, these signs are very useful in identifying the culprit vessel in inferior myocardial infarction.     

Downstream resistance effects of intracoronary thrombosis in the stenosed canine coronary artery.

OBJECTIVE: The presence is well established in unstable angina of intracoronary thrombosis in a stenosed epicardial coronary artery. The effects of the thrombus formation on the distal microcirculation are however still unclear. METHODS: We adapted the Folts canine model of left circumflex coronary arterial stenosis and intracoronary thrombosis by the insertion of a pressure catheter distal to the stenosis and by the use of 15 microns radioactive microspheres for measurement of regional myocardial blood flow. This permitted measurement during circumflex artery occlusion of collateral flow, downstream vascular resistance and collateral resistance. RESULTS: Distal circumflex resistance, obtained by dividing the distal circumflex coronary pressure gradient by the collateral flow, significantly increased with thrombosis (94.47 +/- 35.72 to 120.06 +/- 34.47; p = 0.0018) mmHg/ml/min/g. Changes in collateral flow and resistance in the presence of thrombosis, during maximum ischaemic vasodilatation, were inconsistent. CONCLUSION: Thrombosis causes increased vascular resistance in the microcirculation distal to the site of injury. This may be of clinical relevance in unstable angina, characterised by episodes of thrombus growth and embolization, in which ischaemic episodes may be worsened by generalised downstream vascular changes.     

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).     

Vulnerability of myocardial collateral perfusion: the impact of episodic hypertension

In patients with coronary artery disease, the presence of left ventricular hypertrophy secondary to hypertension is associated with an increased collateral development. A patient is described who was admitted for myocardial ischemia and severe hypertension. One day after admission, coronary angiography revealed a proximal chronic occlusion of the left anterior descending artery with an extensive collateral vascularization originating from the right and circumflex coronary arteries. In addition, left ventriculography showed antero-apical akinesia that was resolved 5 days later, indicating myocardial stunning. This case illustrates the vulnerability of collateral coronary blood flow to an episode of hypertension, giving rise to myocardial ischemia and even myocardial stunning. This finding advocates aggressive antihypertensive therapy in patients with coronary artery disease and regional myocardial perfusion, which exclusively depends on collateral blood flow.