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Dissecting aortic aneurysms: a clinicopathological study. I. Clinical and gross pathological findings.

One hundred and seventy-one patients with dissecting aneurysm seen between 1951 and 1976 at three hospitals in Manchester were studied. There were 60 proximal dissections, 80 distal dissections, 10 abdominal dissections and in 21 the site of origin was uncertain. Pain was the major symptom in 88 per cent of patients; radiation of pain to the interscapular region was much more common in distal dissections. Systemic hypertension was present in 77 per cent, being commoner in distal dissections (83 per cent) than in proximal dissections (70 per cent). Aortic incompetence, hemiplegia and shock were all more common in proximal dissections. Post-mortem examination was performed in 125 patients. Eighty-four per cent of proximal dissections had ruptured, 74 per cent into the pericardium and five per cent into the left pleural cavity. Seventy per cent of distal dissections had ruptured, 11 per cent into the pericardium and 41 per cent into the left pleural cavity. The extent of the dissection was analysed, and it was shown that 25 per cent of distal dissections had extended proximally into the ascending aorta and arch. This implies that diagnosis of the site of origin of dissection from clinical signs and the plain chest-radiograph is inaccurate. Aortography is required for precise assessment. Since treatment often varies with the site of dissection, aortography should be performed in most patients surviving the first few hours. Attention is drawn to the frequency (10.4 per cent) of multiple aortic lesions, and to the occasional aetiological significance of giant-cell arteritis, and, possibly, hypothyroidism.