HIGH PREVALENCE OF ACUTE MYOCARDIAL DAMAGE IN A HOSPITAL NECROPSY SERIES, SHOWN BY C9 IMMUNOHISTOLOGY

Aims-To use a sensitive test of acute myocardial damage-immunohistolog ical detection of complement component C9-to assess the prevalence of damage in an unselected series of hearts taken at necropsy in adults. Methods-Sections of formalin fixed and paraffin wax embedded myocardiu m were cut from 128 consecutive necropsy cases on which a block of hea rt had been taken, These were stained with an immunohistological metho d for C9, Necropsy findings were reviewed and clinical risk factors fo r myocardial damage noted, The extent of C9 immunostaining was correla ted with clinical and pathological findings. Results-There was immunos taining for C9 in 109 heart sections (85%), Most had conventional evid ence of coronary artery disease or acute or chronic myocardial abnorma lity, but necrosis was identified by orthodox microscopy in only 12 (1 1% of C9 positive cases), In 29 cases, orthodox examination showed no abnormality, but C9 was detected, These cases had clinical risk factor s for damage such as hypoxia and hypotension, Increasing age, heart we ight, and total number of risk factors and pathological findings were associated with increasing extent of C9 immunostaining. Conclusions-Ac ute myocardial damage was common in a hospital necropsy series and its prevalence was underestimated by conventional pathological techniques , Immunostaining for C9 was a simple and useful way of detecting such damage.