Combined Stump Pressure and Oximetry for Shunt Use During Carotid Endarterectomy

Optimal cutoff value of carotid stump pressure for determining the need for a carotid shunt in carotid artery endarterectomy

OBJECTIVE

This study was conducted to identify the diagnostic value of carotid stump pressure for determining the need for a carotid artery shunt in patients undergoing carotid artery endarterectomy.

MATERIALS AND METHODS

Carotid stump pressure was prospectively measured in all carotid artery endarterectomies performed under local anesthesia between January 2020 and April 2022. The shunt was selectively used when neurological symptoms appeared after carotid cross-clamping. Carotid stump pressure was compared between patients who needed shunting and those who did not. Demographic and clinical characteristics, hematological and biochemical parameters, and carotid stump pressure of the patients with and without shunts were statistically compared. To determine the optimal cutoff value and diagnostic performance of carotid stump pressure for identifying the patients who need a shunt, receiver operating characteristic analysis was performed.

RESULTS

Overall, 102 patients (61 men and 41 women) who underwent carotid artery endarterectomy under local anesthesia were included, with an age range of 51-88 years. A carotid artery shunt was used in 16 (8 men and 8 women) patients. The carotid stump pressure values of the patients with a shunt were lower than those without a shunt (median (min-max): 42 (20-55) vs 51 (20-104), p < 0.0006). In the receiver operating characteristic curve analysis performed to determine the need for a shunt, the optimal cutoff value of carotid stump pressure was ≤48 mmHg, sensitivity was 93.8%, and specificity was 61.6% (area under the curve: 0.773, p < 0.0001).

CONCLUSION

Carotid stump pressure has sufficient diagnostic power to determine the need for a shunt, but it cannot be used alone in the clinical setting. Instead, it can be used in combination with other neurological monitoring methods.

Surgical Technique for Carotid Endarterectomy: Current Methods and Problems

Over the last 60 years, many reports have investigated carotid endarterectomy (CEA) and techniques have thus changed and improved. In this paper, we review the recent literature regarding operational maneuvers for CEA and discuss future problems for CEA. Longitudinal skin incision is common, but the transverse incision has been reported to offer minimal invasiveness and better cosmetic effects for CEA. Most surgeons currently use microscopy for dissection of the artery and plaque. Although no monitoring technique during CEA has been proven superior, multiple monitors offer better sensitivity for predicting postoperative neurological deficit. To date, data are lacking regarding whether routine shunt or selective shunt is better. Individual surgeons thus need to select the method with which they are more comfortable. Many surgical techniques have been reported to obtain distal control of the internal carotid artery in patients with high cervical carotid bifurcation or high plaque, and minimally invasive techniques should be considered. Multiple studies have shown that patch angioplasty reduces the risks of stroke and restenosis compared with primary closure, but few surgeons in Japan have been performing patch angioplasty. Most surgeons thus experience only a small volume of CEAs in Japan, so training programs and development of in vivo training models are important.

The effect of cerebral oximeter use on the shunt placement concerning carotid endarterectomy surgery

Background:

During carotid arterial endarterectomy (CAE) surgery, an intraluminal shunt is used to prevent hypoperfusion, which can be caused by a cross-clamping cerebral ischemia. However, routine shunt use is not recommended. Various cerebral monitoring techniques are used to determine the need for shunt placement. In this study, retrospective analysis of data on the efficacy of cerebral oximetry in the decision of shunt use during elective CAE surveys was planned.

Materials and Methods:

We collected data on 68 patients operated under general anesthesia between December 2016 and December 2017. Patients were evaluated for near infrared spectrometry (NIRS) and stump pressure values and whether shunt was placed or not.

Results:

Eight (11.7%) patients were shunting. NIRS value after cross-clamping was lower in patients with shunt. Stump pressure values were below 40 mmHg.

Conclusions:

Cerebral monitoring in elective CAE operations has great importance in determining the necessity of using intraluminal shunt to reduce the complications that may occur.

Surgical Pitfalls in Carotid Endarterectomy: A New Step-By-Step Approach

Carotid endarterectomy (CEA) is a surgical intervention that may prevent stroke in asymptomatic and symptomatic patients. Our aim was to examine the microsurgical anatomy of carotid artery and other related neurovascular structures to summarize the CEA that is currently applied in ideal conditions. The upper necks of 2 adult cadavers (4 sides) were dissected using ×3 to ×40 magnification. The common carotid artery, external carotid artery (ECA), and internal carotid artery were exposed and examined. The surgical steps of CEA were described using 3-D cadaveric photos and computed tomography angiographic pictures obtained with help of OsiriX imaging software program. Segregating certain neurovascular and muscular structures in the course of CEA significantly increased the exposure. The division of facial vein allowed for internal jugular vein to be mobilized more laterally and dividing the posterior belly of digastric muscle resulted in an additional dorsal exposure of almost 2 cm. Isolating the ansa cervicalis that pulls hypoglossal nerve inferiorly allowed hypoglossal nerve to be released safely medially. The locations of the ECA branches alter depending on their anatomical variations. The hypoglossal nerve, glossopharyngeal nerve, and accessory nerve pierce the fascia of the upper part of the carotid sheath and they are vulnerable to injury because of their distinct courses along the surgical route. Surgical exposure in CEA requires meticulous dissection and detailed knowledge of microsurgical anatomy of the neck region to avoid neurovascular injuries and to determine the necessary surgical maneuvers in cases with neurovascular variations.