Major embolic complications of open heart surgery and DDA.

Letters to the Editor will be published, if suitable, as space permits. They should not exceed 1,000 words (typed double space) in length, and may be subject to editing or abridgement. To the Editor: I read with interest the article by Furlan & Brueur on "Central Nervous System Complications of Open Heart Surgery". DDA is a variant of atherosclerosis which includes patients with "brittle aortas" wherein showers of cholesterol emboli repeatedly occur spontaneously or from trauma. I believe it is possible that a relatively high percentage of patients who suffered major embolic complications from open heart surgery had DDA. It would be of interest to know whether there was any evidence for a preponderance of this disorder pre-operatively in patients who had post-operative CNS complications. Pre-surgical erythrocyte sedimentation rates, cranial CT scans showing small lacunar-type in-farcts especially in the caudate nuclei and a history of ischemic disturbances including the gastrointestinal system might be considered pre-sumptive evidence of pre-existing low-grade DDA. 1 agree with the author's search for defects in cerebral auto-regulation in such patients but perhaps also one should search for sensitive indicators of low-grade chronic cholesterol embolization pre-operatively in such patients. Moreover anticoagulation might be withheld or reduced in such patiens because there is evidence that such patients have a greater risk of complications from anticoagulation. The previous letter was submitted to the authors and following is their reply. To the Editor: We agree with Dr. Coppeto that atheromatous embolization from the aorta is a potential risk during coronary artery bypass graft (CABG) surgery, but doubt that this risk can be quantitated pre-operatively. During CABG surgery atherosclerotic plaques are frequently seen in the aorta, although the aorta is considered "unclampable" in only one patient per thousand (Golding LR: personal communication). Our surgeons avoid cannulating or clamping obviously diseased segments of aorta, yet an audible crunch is sometimes heard as the aortic cross-clamp is applied. Thurlbeck et al 1 speculated that turbulence proximal to an aortic cross-clamp would tend to "churn up" atheromatous material and pre-dispose to embolism. How often this occurs during CABG surgery, and whether such factors as anticoagulation modify this risk is unknown. Multiple atheromatous brain emboli are rarely found in large series of open heart surgery cases coming to autopsy. 2 ' 3 Subtle neuropsychiatric disturbances after open heart surgery have been ascribed to microembo-lism (ie, <20 microns) of air, fat, paniculate matter and platelet/fibrin clumps …