LETTER TO THE EDITOR
Decreased incidence of postoperative stroke following off-pump coronary artery bypass: Reply
Jan van der Linden, MDa,
Leonidas Hadjinikolaou, MDa,
Per Bergman, MDa and
Dan Lindblom, MDa
a Department of Cardiothoracic Surgery and Anesthesiology, Karolinska Institutet, Huddinge University Hospital, SE-14186 Stockholm, Sweden
We appreciate the interest of Dr. Karamanoukian and colleagues in our study about the relation between postoperative stroke in cardiac surgery and presence, location and extent of atherosclerosis in the ascending aorta (1). Our study showed a 3.5% incidence of stroke due to atherosclerosis of the ascending aorta as detected by epiaortic ultrasound (in 26% of the patients) despite minor surgical modifications. Furthermore, a multivariate analysis showed that the two best predictors for perioperative stroke were atherosclerosis of the ascending aorta and diabetes mellitus. Age is usually associated with atherosclerosis in the ascending aorta. Consequently, atherosclerosis of the ascending aorta (detected by intraoperative ultrasound) is a better predictor than age. Therefore, we recommended a more radical change in surgical strategy in the presence of atherosclerosis of the ascending aorta, and especially when the disease of the aortic wall is extended.
One interesting option in this situation is off-pump coronary artery bypass (OPCAB). Still, partial clamping of the ascending aorta is usually used in OPCAB. Clamping of the ascending aorta has been shown to generate cerebral emboli (2–5). Thus, with OPCAB cross-clamping can be avoided, but usually partial clamping is conducted, unless an anastomotic device is employed or the ascending aorta is totally avoided. A further possibility is the use of intraoperative intraaortic filters, if clamping is necessary (5).
We congratulate Dr. Karamanoukian and colleagues for their successful results with OPCAB in octogenarians. Notably, approximately 12% of their patient cohort had atherosclerosis of the ascending aorta, presumably detected by palpation. It is unclear how these patients were handled in terms of proximal anastomosis on the ascending aorta. Considering that their patients received only on average 1.8 grafts, we assume that their conclusion should be that OPCAB incomplete revascularization without touching the ascending aorta may be the preferred operative technique in high-risk patients (i.e., octogenerians).
Recently, we employed OPCAB to achieve complete revascularization in 20 patients with extensive disease of the ascending aorta according to intraoperative ultrasound and totally avoided the ascending aorta in the majority of the patients. None of the 20 patients suffered a perioperative stroke.
In conclusion, we believe that OPCAB techniques may have a justified place in high-risk patients (i.e., with extended atherosclerosis the ascending aorta according to epiaortic ultrasound) in order to prevent perioperative stroke. However, well-designed randomized studies have to be conducted to prove the superiority of OPCAB over conventional coronary surgery.
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References
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1. van der Linden J, Hadjinikolaou L, Bergman P, Lindblom D. Postoperative stroke in cardiac surgery is related to the location and extent of atherosclerotic disease in the ascending aorta. J Am Coll Cardiol. 2001;38:131–135[Abstract/Free Full Text]
2. Barbut D, Yau FS, Hager DN, et al. Comparison of transcranial Doppler ultrasound and transesophageal echocardiography to monitor emboli during coronary artery bypass surgery. Stroke. 1996;27:87–90[Abstract/Free Full Text]
3. Barbut D, Lo YW, Gold JP, et al. Impact of embolization during coronary bypass grafting on outcome and length of stay. Ann Thorac Surg. 1997;63:998–1002[Abstract/Free Full Text]
4. Barbut D, Yao FS, Lo YW, et al. Determination of size of aortic emboli and embolic load during coronary artery bypass grafting. Ann Thorac Surg. 1997;63:1262–1267[Abstract/Free Full Text]
5. International Council of Emboli Management (ICEM) Study GroupVan Boven NW. The role of aortic clamp manipulation as a source of particulate emboli generation: risk factors and outcomes of the ICEM study group. (abstr)Ann Thorac Surg. 2000;70:1790[Abstract]
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