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Brain microemboli during cardiac surgery or aortography
D M Moody1, M A Bell, V R Challa
1Department of Radiology, Bowman Gray School of Medicine, Wake Forest University, Winston-Salem, NC 27103.
Abstract:
We have observed many focal dilatations or very small aneurysms in terminal arterioles and capillaries of 4 of 5 patients and 6 dogs who had recently undergone cardiopulmonary bypass. A smaller number of sausagelike dilatations distended medium-sized arterioles. Two other patients had a small number of the same microvascular changes following proximal aortography. Thirty-four patients and 6 dogs not undergoing cardiopulmonary bypass had none. (A 35th patient who had not undergone cardiopulmonary bypass or aortography showed a small number of dilatations; mediastinal air was a suggested source.) Some of the dilatations exhibited various forms of birefringence. Because most of the dilatations appear empty, we speculate that they are the sites of gas bubbles or fat emboli that have been removed by the solvents used in processing. These microvascular events, occurring only in conjunction with major arterial interventions, may be the anatomical correlate of the neurological deficits or moderate to severe intellectual dysfunction seen in at least 24% of patients after cardiac surgical procedures assisted by cardiopulmonary bypass.
Insights
Microvascular changes like focal dilatations were observed in patients and dogs after cardiopulmonary bypass. These findings may explain neurological deficits following cardiac surgery.
Area of Science:
- Vascular Biology
- Cardiovascular Surgery
- Neurology
Background:
- Cardiopulmonary bypass is a critical procedure in cardiac surgery.
- Neurological deficits are a known complication after cardiac surgical procedures.
- The underlying microvascular mechanisms remain incompletely understood.
Purpose of the Study:
- To investigate microvascular changes in patients and animals following cardiopulmonary bypass.
- To explore potential anatomical correlates for post-operative neurological dysfunction.
Main Methods:
- Histopathological examination of microvasculature in patients and dogs.
- Comparison between subjects who underwent cardiopulmonary bypass and control groups.
- Observation of microvascular alterations such as focal dilatations and aneurysms.
Main Results:
- Focal dilatations and aneurysms in terminal arterioles and capillaries were observed in 4/5 patients and 6/6 dogs post-cardiopulmonary bypass.
- Sausage-like dilatations were noted in medium-sized arterioles.
- Similar, but fewer, changes were seen in two patients after proximal aortography; control groups showed no such changes.
- Some dilatations exhibited birefringence and appeared empty, suggesting they might be sites of gas or fat emboli.
Conclusions:
- Microvascular changes, including focal dilatations, occur specifically after major arterial interventions like cardiopulmonary bypass.
- These observed microvascular events are a potential anatomical basis for neurological deficits and cognitive dysfunction seen in patients post-cardiac surgery.
- Further research is warranted to confirm the role of these microvascular alterations in post-operative neurological complications.