Asian Cardiovasc Thorac Ann 2003;11:122-126
© 2003 Asia Publishing EXchange Ltd
The Prevalence and Clinical Profile of Angiographic Coronary Ectasia
Peter Nyamu, MMed,
Mullasari S Ajit, MD,
Peter K Joseph, MRCP,
Lakshmi Venkitachalam, Mphil,
Nancy A Sugirtham, PhD
Institute of Cardiovascular Diseases, Madras Medical Mission, Mogappair, India
For reprint information contact: Mullasari S Ajit, MD Tel: 91 44 2656 5961 Fax: 91 44 2656 5859 email: icvd{at}eth.net Institute of Cardiovascular diseases, Madras Medical Mission, 4A Dr. JJ Nagar, Mogappair, Chennai 600 050, India.
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ABSTRACT
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Coronary artery ectasia, a variant of coronary atherosclerosis, is a relatively rare entity. Review of literature did not reveal an exclusive study on isolated ectasia. We decided to analyse the clinical presentation and angiographic prevalence of this subset. A retrospective study of patients who underwent coronary angiogram in our institute over the past six years was carried out and the epidemiological, clinical and angiographic characteristics of patients with isolated ectasia were analysed. Distribution of ectasia was with a modification of the Markis classification. Among 6938 angiograms analysed, 134 (2%) had isolated ectasia. Of the 118 symptomatic patients, 34 (25%) had a history of or presented with infarction, with correlation between the territory of infarction and the ectatic vessel in 32 patients. Of 62 patients with lipid abnormality, Hypertriglyceridemia in 42 (65%) was the most common. The left anterior descending artery was the most common vessel involved. Diffuse ectasia most commonly involved the right coronary artery. One patient had spontaneous coronary dissection. There is a relatively high prevalence of isolated coronary ectasia with predominant involvement of the right coronary vessel when diffuse and the left anterior descending artery when discrete. This entity is not innocuous and warrants a detailed study on the available management options.
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INTRODUCTION
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Coronary artery ectasia, also known as dilated coronopathy, is a relatively rare entity with an estimated incidence of 0.3 – 4.9%.1,2 This pathological entity is defined as dilatation of a part or whole of the coronary artery 1
times or more the diameter of an adjacent normal segment.3 It is commonly associated with atherosclerotic coronary artery disease (CAD) and therefore also considered as a variant of coronary atherosclerosis. There are reports of ectasia as an isolated congenital defect and also in association with polyarteritis nodosa, Takayasu’s disease, Scleroderma, Syphilis, bacterial infections, iatrogenic causes and Kawasaki disease.4 Previous studies have shown pure coronary ectasia not to be completely innocuous with 50% of patients presenting with myocardial infarction (MI) and many having angina.5 Markis et al. found a 15% mortality rate after 7 years, which at the time of their publication was equivalent to the mortality rate of medically treated triple vessel disease.6,7 Current literature also suggests that arteries with isolated ectasia are subject to slow flow with thrombus formation, vasospasm and spontaneous dissection. A well-established treatment protocol is not available with the existing recommendations including the use of anticoagulants, antiplatelets and coronary vasodilators based on anecdotal reports.8 We studied the clinical and angiographic presentation of coronary artery ectasia.
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PATIENTS AND METHODS
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We retrospectively analyzed 6938 patients who underwent coronary angiogram in our institute between January 1995 and December 2001. The reasons for catheterisation of these patients were history of angina, previous or an acute myocardial infarction, positive treadmill test and / or presence of multiple coronary risk factors. Patients with valvular or congenital heart disease and cardiomyopathies were excluded. For every patient included, epidemiological, clinical parameters and appropriate investigations such as electrocardiogram (ECG), echocardiography, treadmill test and lipid profile were obtained. The definition of coronary artery ectasia employed was that used in the Coronary Artery Surgery Study (CASS), where a vessel was considered ectatic when its luminal diameter exceeded 1.5 fold the adjacent normal segment.9 Discrete ectasia was defined when the ectatic segment was less than 1 cm and diffuse when it was more than or equal to 1 cm in length. In cases of diffuse ectasia, the diameter of the corresponding artery in a normal angiogram was taken as the reference. Assessment of the severity of ectasia and CAD was done visually by a panel of experienced cardiologists and technicians and subsequently confirmed by Quantitative Computerised Analysis. Co-existing coronary artery disease with luminal narrowing < 50% was considered non-flow limiting and patients with > 50 % luminal narrowing were excluded from the study group. Since it was not possible to group all the patients as per the Markis classification6, some modification on the classification was made as follows:
- Isolated diffuse ectasia
- in only one vessel
- in 2 or all 3 coronary vessels
- Diffuse and discrete ectasia in combination
- Discrete involvement of 1 artery with diffuse involvement of 2 or 3 coronary arteries
- Diffuse in 1 and discrete involvement of two or more coronary arteries
- Diffuse in 1 and discrete in one coronary vessel
- Isolated discrete ectasia
- in one vessel
- in two or more coronaries
- Involvement of left main coronary artery (LMCA)
- isolated involvement
- involvement of other vessels
Hypertension was defined as blood pressure > 140 / 90 mm Hg or patients already being on anti-hypertensive therapy. Lipid abnormality was defined as elevation in total cholesterol (TCL) > 200 mg•dl-1, triglycerides (TGL) > 180 mg•dl-1, low-density lipoprotein (LDL) > 130 mg•dl-1 or reduced high density lipoprotein (HDL) < 35 mg•dl-1. Treadmill test (using the Bruce protocol) was considered positive when horizontal or down-sloping ST depression of 
2 mm was observed during exercise with or without chest pain. Details of clinical follow-up with relevant investigations were analyzed with respect to the nature of treatment advised. The Chi squared Test of Association (
2) and Proportion test were used as statisical tools wherever appropriate.
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RESULTS
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Of the 6938 angiograms retrospectively analyzed, ectasia without flow limiting CAD was found in 134 patients, a prevalence of 1.9%. A predominance of the male sex was seen (111, 83%). The age range was 28 to 72 years with a mean ± standard deviation of 52.1 ± 10.3 years. The baseline characteristics of patients is as given in Table 1
. The majority of patients belonged to the age group of 40–60 yrs. Most of the patients (88%) were symptomatic (Class I-IV Angina - New York Heart Association Classification) at angiographic presentation with 34 (25%) of them presenting with either history of myocardial infarction or acute myocardial infarction. Seventy two (54%) patients were hypertensive, 40 (30%) were smokers and 36 (27%) were diabetic. Lipid abnormalities were detected in 64 (48%) patients with elevated triglycerides being the most common abnormality, seen in 42 (66%) patients. 119 patients (89%) had good left ventricular (LV) function while 3 (2%) had severe LV dysfunction. Treadmill test was done in 52 patients and was positive for inducible ischaemia in 39 (75%) of them. The ECG was normal in 68 (51%) patients with evidence of myocardial infarction in 34 (25%) patients.
The vessel distribution of involvement is as shown in Table 2. The left anterior descending artery (LAD) was the most common vessel involved followed by the right coronary artery (RCA) and the left circumflex artery (LCX). The left main coronary artery was involved in only 5 (3%) patients with 4 of them showing diffuse ectasia of the entire coronary tree. A significant association was seen between the vessel involved and the nature of ectasia (2 = 37.618; p < 0.001). We found a single coronary artery is more commonly involved in discrete ectasia and involvement of more than one coronary artery in the diffuse form of ectasia. The distribution of vessels involved as per the modified Markis classification and its relation to age group, coronary risk factors and incidence of myocardial infarction is given in Table 3. Type I was the most common presentation noted followed by Type III.
Of the 34 patients who had myocardial infarction, 32 (94%) patients showed correlation between the territory of infarction and the ectatic vessel. The pattern of involvement of coronary arteries was similar to that noted in the total study group with LAD being the most common vessel involved. However, when the nature of ectasia was considered, a predominance of the III subset was seen in patients with myocardial infarction unlike that of group I in the non-myocardial infarction group (Table 4). Spontaneous dissection of coronary artery was seen in only one patient who had sustained an acute myocardial infarction. Hyperlipidemia was the most prevalent risk factor with 57% of patients having elevated lipids. 22 (65%) patients were on therapy with anti-platelets only, 8 (24%) on anti-platelets + anti-coagulants and 1 (3%) was on anti-coagulants only. Twelve (35%) patients were on Statins. Clinical follow-up for a mean period of 1.4 years (range: 3 months – 4 years) of 41 patients was possible. Of the 41 patients, 18 were in the myocardial infarction subgroup. Only one patient was symptomatic (Class II Angina - New York Heart Association Classification) and he was in the myocardial infarction subgroup.
The line of management adopted along with the follow-up data in the total population is shown in Table 5. During follow-up, 9 patients had the treadmill test done, of which only one was positive for inducible ischaemia and that was at 12 mets. None of the patients available for follow-up had myocardial infarction, cardiac death or required any intervention.
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DISCUSSION
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Coronary artery ectasia is considered an uncommon angiographic finding with varying patterns of presentation and prevalence. A number of studies and analysis have been conducted with a view to understand this entity and try to establish an effective line of management.3,9–12 However, to the best of our knowledge there has been no study exclusively on ectasia with non-flow limiting CAD. In studies where this entity has been evaluated as a sub-group, the numbers studied were rather modest when compared to that in our study.5,6,11 Some of the mechanisms postulated to explain ectatic transformation include arteriosclerotic disease resulting in weakening of media3,13 and post - stenotic dilatation with post - stenosis flow velocity augmentation.10,14 According to Tunick et al., discrete ectasia develops exclusively in the presence of tight stenosis.10 In our study, however, we identified patients with isolated discrete ectasia without significant co-existing stenosis.
Lipid abnormalities have been incriminated in the genesis of ectasia with one study showing increased prevalence in patients with Familial Hypercholesterolemia and a strong inverse association between High Density Lipoproteins and ectasia.15 In our study, only 2 patients have been noted to have low HDL levels. Elevated triglycerides was the most common lipid abnormality seen in our study while none of the patients studied by Harikrishnan et al. had hypertriglyceridemia.5
According to most investigators, age did not seem to have any additional influence in the distribution of ectasia. Sharma et al. found no difference in the nature of ectasia in older or younger patients.13 Our study concurs with the above finding in that no specific difference was seen in the pattern of ectasia between the various age groups. Most of our patients belonged to the age group of 40–60 years which is more prone to CAD. However, it is interesting to note that a predominant number of patients in the myocardial infarction subgroup were < 40 years of age suggesting that ectasia could be a predisposing factor resulting in myocardial infarction especially in the young.
In their series, Demopoulos11 and Harikrishnan5 found the RCA to be the most commonly involved vessel followed by the LCX and later the LAD. This is contrary to our findings where the LAD was the most common vessel involved. As in the above studies, ectasia of diffuse nature was predominantly seen in RCA with LAD showing predominantly the discrete form of ectasia.
A significant proportion of our patients – 34 (25%) - at presentation either had an acute myocardial infarction or a history of myocardial infarction while 65 (49%) patients had angina. These compare well with the 39% of angina and myocardial infarction reported by Demopoulos et al.11 This goes to show that coronary ectasia may not be a benign condition. Moreover, the finding of coronary artery dissection in one of our patients relates to the suggestion that ectatic arteries are prone to dissection.8
There has always been a controversy regarding the use of anticoagulants in patients with coronary ectasia. The recommendation of systemic anticoagulation by Swanton et al.16, was based on only one patient they had studied and the suggestion was made "in view of the tendency for mural thrombosis to occur in ectatic leg vessels, cerebral arteries and probably coronary arteries". However, Demopoulos et al.11 felt that the necessity of long-term anticoagulation cannot be justified as their follow-up outcome over 2 years and those of Farto e Abreu14 over 5 years showed no incidence of unfavourable events in patients not on anticoagulants. Takahashi et al.17, in their comparison of diffuse and localised coronary ectasia, conclude that patients with diffuse coronary ectasia should be followed up carefully. Of the 41 patients followed up in our study, 40 of them were asymptomatic and none had any major events; only one patient on anti-platelets required optimisation of medical management for unstable angina. Given the risks of hemorrhage associated with anticoagulation, its recommendation needs to be reviewed with a larger population and if adopted, low-dose therapy would probably be more appropriate.
The limitations of our study include the relatively small number of patients followed up and lack of angiographic follow-up. Furthermore, estimation of stenosis in the presence of ectasia was done visually - however quantitative computerised analysis was used to confirm visually selected cases of ectasia.
In conclusion, our study shows a relatively high angiographic prevalence of isolated coronary ectasia with a predominant involvement of the RCA when diffuse and the LAD when discrete. Coronary ectasia in the absence of flow-limiting coronary artery disease may not be completely innocuous, since there is an association with angina and myocardial infarction. Thus, the suggestion of the ‘slow-flow’ phenomenon and in-situ thrombosis even in the absence of obstructive CAD probably holds true. The uneventful follow-up course in our small cohort of patients necessitates a larger study and a longer follow-up period with a view to review the management strategies including the use of anti-coagulants.
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ABSTRACT
INTRODUCTION
