'Coronary intimal fibrous stenosis' - early coronary atherosclerosis causing acute myocardial infarction : a case presentation and overview
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A 34-year-old Coloured man had typical angina pectoris which was unresponsive to medical therapy. There was no history of factors predisposing to atherosclerosis apart from moderate cigarette smoking. A resting ECG suggested a previous nontransmural anterolateral myocardial infarction, and a submaximal effort test was strongly positive for myocardial ischaemia. Serological investigation for syphilis was positive, and initially the possibility that coronary ostial stenosis was the cause of his symptoms was strongly considered. Cardiac catheterization and selective coronary angiography showed evidence of an anterolateral myocardial infarction and that there was no coronary ostial stenosis, but total occlusion of the left anterior descending coronary artery (LAD) proximally with retrograde filling from the right coronary artery was revealed. The left circumflex coronary artery also showed some insignificant internal luminal irregularities. The patient was subjected to coronary artery bypass graft (CABG) surgery with saphenous grafts to the proximal LAD as well as its first diagonal branch. Proximally the LAD was a firm fibrotic cord; biopsy specimens were taken from this as well as part of the adjacent myocardium and aorta. The artery showed severe fibrous proliferation of the intima without any calcium or lipid deposits, which would have been expected with atherosclerosis, as well as an organized thrombus. There were no signs of cardiovascular syphilis. The patient made quite a dramatic recovery with disappearance of the angina and improved results on submaximal stress testing. A month later cardiac catheterization showed improved segmental anterolateral contractility of the left ventricle as well as patency of both CABGs. Some 3 months postoperatively he again complained of angina, which gradually worsened on treatment. Stress testing again showed significant ischaemia and a second postoperative cardiac catheterization 10 months after surgery showed both CABGs to have occluded. The patient, who is on medication, is being followed up. A pathological diagnosis of early coronary atherosclerosis was made. This lesion has been previously termed 'coronary intimal fibrous stenosis' as the authors concerned did not believe that it was due to coronary atherosclerosis. Ours is the third such case documented in the literature. Reference to earlier literature on coronary atherosclerosis confirms that this histological picture is in keeping with the early phase of this disease. The 'classic' features of coronary atherosclerosis may not have been evident on account of the patient's dietary habits, which may prove to be the important pathological differentiating feature in our White and Coloured population groups.