Ref – Nishi, K., Asada, M., Sakaguchi, I., Nakagawa, T., Furukawa, S., Takaya, A., Uemura, C. Total and severe right coronary artery ectasia with a luminal dilatation exceeding 2cm on the epicardium - An autopsy case. Anil Aggrawal's Internet Journal of Forensic Medicine and Toxicology [serial online], 2011; Vol. 13, No. 2 (July - December 2012): [about 6 p]. Available from -
Title - Total and severe right coronary artery ectasia with a luminal dilatation exceeding 2cm on the epicardium- An autopsy case -
Katsuji Nishi(1,2), Mayumi Asada(2), Ikuo Sakaguchi(1), Tokiko Nakagawa,(1,2), Satoshi Furukawa (1,2), Akari Takaya(1,2), Chikako Uemura(1)
1: Department of Legal Medicine, Shiga Univesity of Medical Sience, Setatukinowa-cho, Ohtsu city, Siga, Japan
2: Osaka Medical Examiner’s Office, Bamba-cho, Osaka city, Osaka, Japan
Abstract
The totally and severely dilated the right coronary artery RCA was found on the heart of a 65 year-old housewife victim. Although the left coronary artery orifice was normal size, the RCA was enlarged with a diameter of 1.8cm at the ostium and normally located. It traveled downward between the right atrium and the right ventricle with increasing up to 2.5cm of its diameter and with meandering. There was no aneurysm and no remarkable arteriosclerosis on the RCA from beginning to distal part of it. However at the distal part (apex of the heat), the RCA showed severe arteriosclerosis with hard calcification and severe bleeding was observed on the right side of the heart. This coronary artery ectasia(CAE) is biggest and longest one in the literature.
Key Words: Coronary Artery Ectasia, Right Coronary Artery, Forensic autopsy
Introduction
Coronary artery ectasia(CAE) or aneurismal coronary artery disease is defined as distension of a part of a coronary vessel of up to one and a half times the diameter of an adjacent normal segment.(1) When the dilation involves the whole vessel, it is more appropriate to use the word” ectasia” than aneurismal disease.(2). CAE was classified into four distinct types proposed by Markis et al (2). The four types ectasia are: I.:Diffuse ectasia with aneurismal lesion in two vessels, II.:Diffuse ectasia in one vessel and discrete in another. III.:Diffuse ectasia in one vessel. And IV.:Discrete ectasia in one vessel.
Case
We encountered an autopsy case of a 65-year-old woman presenting with severelyenlarged heart with 640g in weight. She entered a private hospital because of dyspnea and pain in the chest and received a diagnosis of five chambers in her heart with echocardiography. Two weeks after admission to the hospital she suddenly died in her house. Autopsy was performed next day at Osaka Medical Examiner’s Office. She was an obese, 154cm in height and weighted 56kg. There was no suspected finding and symptom concerning Marfan and/or Ehler-Danlos syndrome.
The heart was enlarged with 14.5×12.3×4.3cm in size. An enlargement of the heart was recognized especially in the right side and severe bleeding was observed in the right ventricle of the heart, as shown in Fig.1.The cross sections of the heart showed normal sized left ventricle, the compressed right ventricle, a massive bleeding of right side of the heart and several strange cavities in the right side of the heartas shown in Fig.2. The strange cavities were detected in the right side of the heat. The cavities were caused by totally dilated and tortuous the right coronary artery (RCA) as shown in Fig.2 and 3.
RCA was severely dilated up to 2.5cm, meandered and run backward on the right side of the heart with keeping almost the same width, just like co-existence of two aortas (Fig.4).The volume of RCA with bleeding occupied over 70% of the right side of the heart. The outer and inner surface of the RCA was smooth(Fig.3) and soft in the proximal and middle part of the artery, and RCA had uniform thickness of its wall without atheromatous plaquesand no large branch, although small arteries were microscopically detected. RCA showed marked sclerosis and calcification at the peripheral part where the artery entered the cardiac muscle, as shown in Fig.3. The right ventricle showed severe bleeding but no fibrosis due to old cardiac infarction. The left ventricle had a thickness of 1.8cm and the left coronary artery was slightly dilated than normal size(Fig.5). There was no evidence of left ventricular fibrosis at macroscopic level.According to Markis et al (2), CEA in the present case belongs to type III, since ectasia is observed only in right coronary artery.
Although RCA resemblesthe ascending aorta in external morphology (Fig.4) and stained morphology by HE (Fig.6), HE staining shows remarkably difference between them, as shown in Fig. 7 and 8. The ascending aorta had clear three layers structure, showing no remarkable pathological change with slight thickening of internal tunic (Fig.7). Macroscopic characteristic of the RCA is the same of the normal coronary artery except unbelievable enlargement. However, HE staining revealed that internal tunicbecame thicker and the internal elastic lamina was tore into fragments. Tunica media showed no regular structure with severely fragmented elastic fibers, showing slight calcification (Fig 8).PAS staining revealed the deposition with mucous substance in the pseudocysts (Fig. 9.). The small artery with arteriosclerosis was detected outside the right coronary artery (Fig.10). A massive bleeding was recognized in the right ventricle, (Fig.11) and a small amount of bleeding was detected by HE stain (Fig. 12).
Pathological examination of other organs reveled no remarkable findings except Hashimoto disease in the thyroid as shown in Fig.13.
Discussion
Concerning to Lumen diameter of normal human coronary arteries, Dodge et al reported that the left main artery measured 4.5±0.5mm, the proximal left anterior descending coronary artery (LAD) and the distal LAD 1.9±0.4mm, for the right coronary artery, proximal diameter varied between 3.9±0.6 and 2.8±0.5mm. Women had smaller epicardial arterial diameter than men(3).
There is a difference between CEA and aneurysm of coronary arteries, although such diseases may be manifestation of the same pathological process(4). The coronary aneurysms have multiple definitions, but the most accepted is the focal increase of the diameter that exceeds 1.5 -2 times the normal adjacent segment(5). Aneurysms can be saccular or fusiform. Saccular aneurysm is defined as the aneurysm with a transverse dimension greater than the longitudinal dimension of the segment, while fusiform aneurysm is an aneurysm with longitudinal dimension of at least 200% of its transverse dimension(6).The lumen of theright coronary artery of the present reportmeasured 2.5cm at proximal part and right epicardial artery keeps almost same lumen diameter and has no irregular swelling. The abnormal dilation of the RCA is surely ectasia and not an aneurysm.
CEA has been observed by pathologists and cardiologist for more than two centuries and was first described by Morgagni (7) in 1761. According to a report by Packard and Weehsler (8), the postmortem finding of right coronary artery dilation in a patient who experienced sudden death was reported by Bourgon in 1812.
Since CEA can be found in between 0.3% to 1.4% at autopsy and in up to 5% during coronary agiography or multidetector computed tomography (9,10, 11), it is not a rare coronary disease, however in the present case right coronary artery totally dilated and expanded its lumen with 2.5cm in diameter. As far as to our knowledge, the CEA in the present case is longest and biggest one with tube shape, since no previous report wasfound in the literature.
Apart from association with Kawasaki disease and coronary fistulae, the etiology of coronary dilation in the pediatric age group is not very clear, and has been associated with coronary atherosclerosis, trauma and hyperlipidaemia in the adult population (12). Although CEA is usually considered to be a variant of coronary atherosclerosis, the minority cause of CEA are congenital or occur due to conditions such asvasculitis, trauma, connective tissue disease, idiopathic mitral valve prolapse syndrome and congenital disorder including Marfan and Ehlers-Danlos syndrome and hypertrophic cardiomyopathy(13).
Although there was no visible atherosclerosis on the right and left epicardial coronary arteries of the present case,the RCA of the present case was calcified at the distal part where the artery enters into the cardiac muscle. It is presumed that compensatory enlargement of right coronary artery was occurred due to obstruction of blood supply in the right ventricle during long period of her life. Antonios et al (14) presented pathogenetic mechanisms of coronary ectasis. They described that activation of proteolytic enzymes and enzymatic degradation of the media are the most critical molecular events leading to a structural defect of the coronary wall, and altered NO metabolism and coronary hemodynamics, in particular low endothelial shear stress, also play a role, whereas the effect of genetic background is yet under investigation.
At the autopsy severe bleeding of right ventricle was observed, and it showed myocardial ischemia and cause of her death. The mechanism of myocardial ischemia in CEA is not clear. It has been suggested that the presence of the aneurismal segments produces sluggish or turbulent blood flow, with an increased incidence of ischemic manifestations or occurrence of acute myocardial infarction as a result, regardless of the actual severity of coexisting stenotic coronary lesions(2). It has been postulated that patients with CAE but without significant coexistent coronary artery disease have a higher incidence of advance events than individuals with normal coronary arteries(2), and that CEA can cause ischemic heart disease, most likely through coronary thrombosis(15). Akyuerek et al (16) indicated that although volumetric coronary blood flow is significantly higher in CEA, microcirculatory dysfunction that is reflected as depressed coronary flow reserve may be the underlying cause of exercise-induced myocardial ischemia.
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Figure Legends
Figure 1. An enlargement was recognized in the right side and severe bleeding was observed in the right ventricle of the heart.
Figure 2. The cross sections of the heart showed normal sized left ventricle, compressed right ventricle, severe bleeding of right side of the heart and several strange cavities in the right side of the heart. The strange cavities caused by dilated ecstatic tortuous right coronary artery.
Figure 3.The ostium of right coronary artery was enlarged and no arteriosclerosis was observed in the proximal and middle of the artery, however, the peripheral part of the artery showed severe arteriosclerosis. The left coronary artery with three branches showed no abnormality.
Figure 4. The aorta (arrow) in the left side of the photo showed normal size with no arteriosclerosis. On the hand, the right coronary artery (arrow head) was severely enlarged.
Figure 5. The left coronary artery (arrow) showed normal size.
Figure 6.The right coronary artery was remarkably dilated and resembled the aorta with slight arteriosclerosis. Severe blooding around the artery was observed.
Figure 7. The ascending aorta stained by HE showed normal morphology with slightly thickening of internal tunic.
Figure 8. HE stain of the coronary artery revealed pseudcyst, thick intima, tired
internal elastic lamina and slight calcification.
Figure 9. PAS staining showed mucous deposition in the pseudcyst.
Figure 10. The small size artery with arteriosclerosis was detected outside the right coronary artery by Azan staining.
Figure 11. Massive bleeding was recognized in the right ventricle.
Figure 12. Small amount of bleeding was observed in the left ventricle.
Figure 13. Severe lymphocyte infiltration was recognized in the thyroidal gland, showing Hashimoto disease.