Maximum preservation of the media in carotid endarterectomy

Abstract

Carotid endarterectomy (CEA) is intended to remove atheromatous plaque by dissecting a plane between the intima and the media (circular medial fibers), but this may not be the optimal dissection plane. The present technique is based on identifying the plane that divides the media from the plaque, so preserving the media on the adventitia as much as possible. This plane is more difficult to find and follow than the easy-to-dissect plane usually located between the media and the adventitia, because the plaque invades the media and so the dividing plane is located within the media. In this prospective observational study, CEA was performed in 22 patients to histologically examine the excised plaques and small samples of the whole arterial wall, and evaluate the clinical outcomes. Plaque had invaded the luminal part of the media in the whole arterial wall sample of 80% of cases. Thin medial layers covering > 80% of the surface of the plaque were found in 16 of 22 plaques (73%). Some atheromatous component was sometimes left in the preserved media, rather than completely removed with the media. No morbidity or mortality had occurred by discharge. Only 1 small ipsilateral infarction (4.5%) and no restenosis of greater than 50% were detected during the mean follow-up period of 7 years. Since the plaque usually invades the media, the optimum dissection plane may be located within the media, dividing it into two layers. The presence of some remnant atheromatous components in the preserved media was not associated with surgical complications or restenosis.

Fig. 1.

Intraoperative photographs showing the meticulous technique to preserve the media (A–E) and a schematic drawing of the present technique (F). A: After initial arterial incision with a scalpel, gentle retraction of the adventitia opened the easiest plane to dissect, just luminal to the adventitia (arrow). A layer of the media (asterisk) was detached from the arterial wall. To preserve the media on the arterial wall, a plane next luminal to the easiest plane should be dissected (dotted arrow). B, C: Using a blunt spatula, the plane to preserve the media (asterisks) was opened and followed (dotted arrows). D: During the effort to find a plane to leave the media attached to the arterial wall, the media sometimes formed a free flap (asterisks). This flap was removed for histological investigation (Fig. 3). E: After completion of plaque removal, smooth transition was formed to the intima of distal internal carotid artery, and yellowish atheromatous components remained with the media (stars). F: Dissection plane was located within the media, dividing it into two layers. The distal end of the endarterectomy smoothly transits to the intima of the internal carotid artery.

Fig. 2.

Intraoperative photographs of removed plaque (A) and arterial wall after atheromectomy (B) from a different case to that presented in Fig. 1. The media (asterisks) was seen as circular fibers on both the arterial wall and the plaque. Partial exposure of the adventitia occurred where a flap of the media was removed (lower, §). Some of the media on the arterial wall was yellowish, indicating residual atheromatous components. The end of the atheromectomy transitioned smoothly to the almost normal intima of the distal internal carotid artery (arrow).

Fig. 3.

Photomicrograph of the flap demonstrated in Fig. 1D (asterisks) showing typical smooth muscle component rich with elastic fibers. Elastica-Masson, original magnification ×400. Scale bar = 20 μm.

Fig. 4.

Photomicrograph of the section near the middle of the removed plaque showing a thin layer of media overlying the plaque (double-headed arrows). #: lumen. Elastica-Masson, original magnification ×40. Scale bar = 20 μm.

Fig. 5.

Photomicrograph of the whole wall sample showing the plaque (white double-headed arrow) and the media (black double-headed arrow); #: lumen. The adventitia has been detached from its primary position (##). Residual internal elastic membrane appears to be present (white arrowheads). Part of the media is infiltrated by atheromatous components (dotted black double-headed arrows). Elastica-Masson, original magnification ×100. Scale bar = 20 μm.

Fig. 6.

Intraoperative photographs of the distal end of the endarterectomy with (A) and without (B) the present technique. A: The preserved media with some residual atheromatous components (stars) smoothly transited to the intima of the internal carotid artery (arrow). B: Most of the media was removed and the adventitia appeared as the red wall (§). The distal end of the endarterectomy did not smoothly transit to the intima of the internal carotid artery (arrow).