Contraction bands in visceral and vascular smooth muscle

Smooth muscle contraction bands (SMCBs) have been described in the gastrointestinal tract, subsequent to acute ischemia, and in the coronary arteries of animals and individuals with a sudden death; in these circumstances SMCBs have been postulated to serve as a premortem marker, and suggested as diagnostically useful. The present investigation was undertaken to determine whether the presence of SMCBs could be correlated with a premortem clinical condition. Retrospectively, the routinely prepared histological sections from 76 autopsy and 93 surgical cases were screened semiquantitatively for the presence of SMCBs. The autopsy sections examined included the gastrointestinal tract, the prostate, and the coronary arteries, as well as all other smooth muscle-containing tissues; the surgical specimens included: coronary artery endarterectomies; saphenous vein bypass grafts; temporal artery biopsies; prostatic curettings; colectomies; varicose veins; leiomyomas of uterus, bowel, and skin; and, leiomyosarcomas. The clinical and pathology reports were reviewed for patient demographics, major clinical diagnoses, presence of shock, details of any resuscitation attempts, time interval to postmortem, and the cause of death. SMCBs were evident in 100% of the gastrointestinal and prostate, and in 96% of the coronary artery autopsy sections examined. All surgical specimens were positive for SMCBs, the exceptions being leiomyomas (positive in 13 of 22; 60%) and leiomyosarcomas (4 of 5; 80%); SMCBs in surgical specimens were less prominent when compared with those observed in autopsy tissue. No correlation was found between the presence of SMCBs and any clinical or demographic parameter assessed, because of the virtual universal occurrence of the SMCBs. The presence of less distinct SMCBs in surgical specimens may very well be artifactual, akin to myocardial and skeletal muscle contraction bands. The observation that SMCBs at autopsy are virtually ubiquitous suggests that they are best considered an agonal phenomenon, and a nonspecific pathological finding.