Prevention of paraplegia during thoracic aortic cross-clamping: Importance of patent internal mammary arteries

Abstract

Unexplained anatomic and physiologic factors account for the unacceptably high rate of paraplegia/paresis after thoracoabdominal aortic reconstruction. We assessed the neurologic significance of patent internal mammary arteries (!MAs) in a hovel rat model of aortic clamping in which the aortic origins of the intercostal arteries (ICAs) were occluded. Methods: Twenty anesthetized, intubated, and halothane-ventilated adult male rats had catheters placed in the carotid and femoral arteries. ICAs arising from the aorta were divided at their origins through a left thoracotomy. IMAs were either divided (IMA-OUT, n = lO) or left intact (IMA-IN, n = lO). Proximal and distal descending aortic clamps were placed for 7 minutes. A neurologic deficit score (NDS) was assigned at 1, 4, 18, 24, and 48 hours by use of an established scoring system. Results: The mean IMA-IN NDS was statistically better than the mean IMA-OUT NDS at 1, 4, 18, and 24 hours with P = 0.0005, 0.0014, 0.0098, and 0.0151, respectively. Moreover, the mortality rate in the IMA-OUT group was statistically greater than in the IMA-IN group (p = 0.0036). Conclusion: In this model, patent lMAs prevent paraplegia when the ICAs are occluded at their aortic origin and the aorta is clamped for 7 minutes.

Cardiac function is a risk factor for paralysis in thoracoabdominal aortic replacement

“…2,28 Experimentally, even direct perfusion of the arteria radicularis magna (artery of Adamkiewicz) during aortic occlusion with reperfusion of all intercostals has no protective effect. 29 There is also strong experimental evidence that collateral blood flow during aortic occlusion is an important factor in cord preservation 30 and that chemical or mechanical shunting of blood away from the cord collaterals (especially the upper thoracic intercostals) has a significant negative effect on spinal cord viability. 31,32 Our paraplegia risk model analysis of clinical reports strongly implies that intercostal reimplantation during aortic occlusion offers no protection from paraplegia, with or without assisted circulation.…”

Endovascular repair for abdominal aortic aneurysm followed by type B dissection

“…We confirmed the patency of all spinal cord collaterals preoperatively, such as the bilateral subclavian arteries, vertebral arteries, internal thoracic arteries, and internal iliac arteries, and we performed a right axillary-to-left axillary arterial bypass to preserve LSCA blood flow. Several studies have reported the importance of preserving these collateral arteries to prevent spinal cord ischemia, 4–6 but due to insufficient findings, the evidence has not yet been established.…”

Strategies for Spinal Cord Protection during Descending Thoracic and Thoracoabdominal Aortic Surgery: Up-to-date Experimental and Clinical Results - A review

“…The cervicodorsal region of the spinal cord is, in fact, supplied also by branches of the costocervical trunk, and by the occipital, deep cervical, and ascending cervical arteries (6). The collateral circulation to the mid-thoracic and thoracolumbar regions of the spinal cord is provided by the intercostal and lumbar vessels and Giglia et al (23), in an experimental rat model, observed that also the internal mammary arteries are important collateral circulation contributors. Christiansson et al (20), interestingly, showed that collateral circulation through proximal feeding vessels such as vertebral arteries and supreme intercostal arteries is prevented by clamping the subclavian arteries and ligating the mammary arteries.…”