•Mostafa, Nasir, Smith

Title:

Body:

Carotid Endarterectomy in a Patient with Subclavian Artery Stenosis: Unmasking the Silent Culprit

Abstract:
This case report presents a vasculopathic patient who underwent a left carotid endarterectomy (LCEA) for asymptomatic carotid artery stenosis (CAS). However, the patient's history of right-arm lymphedema following radical mastectomy and severe left subclavian stenosis contributed to falsely low blood pressure readings in the left arm, leading to poorly controlled hypertension and subsequent complications in the postoperative period. This case highlights the importance of recognizing subclavian stenosis as a potential confounding factor in blood pressure assessment and underscores the need for alternative measurement techniques to ensure optimal hypertension management in similar patients.

Case Presentation:
A 68-year-old female with a history of right lumpectomy in 2007 for invasive lobular cancer and subsequent completion mastectomy in 2022 for recurrence complicated by right arm lymphedema was scheduled for LCEA in 2023. Surveillance carotid ultrasonography revealed left internal carotid artery stenosis greater than 80% and right internal carotid stenosis of 60%. During the preoperative cardiology visit, mild hypotension was noted when using left arm cuff measurements, leading to the discontinuation of thiazide and losartan, and a reduction in nebivolol dose. The patient was cleared for surgery with an acceptable risk profile.

Methods:
A computed tomography angiography (CTA) review revealed severe left subclavian stenosis, prompting the placement of a right radial arterial line for more accurate blood pressure monitoring before surgery. The carotid endarterectomy was performed uneventfully, but persistent hypertension in the recovery room required a Nicardipine drip. There was a significant discrepancy between the blood pressure readings obtained from the right radial arterial line and the left arm cuff measurements. Multiple extremity cuff measurements were conducted to match the right arterial line readings, with the right thigh providing the closest match. Suboptimal outpatient hypertension treatment likely explained postoperative hypertension. Once the patient was off Nicardipine and accurate non-invasive measurements were obtained via the right thigh, the arterial line was removed. The patient was later discharged and antihypertensive medication was adjusted for good blood pressure control.

Discussion:
Subclavian artery stenosis and lymphedema can significantly affect blood pressure and its management. Subclavian artery stenosis from atherosclerotic plaque buildup leads to decreased blood pressure in the affected upper extremity. Therefore, measuring blood pressure in both upper extremities is crucial to optimally manage hypertension. According to clinical guidelines, blood pressure readings should be avoided in women with breast cancer to avoid the development of lymphedema; however, the National Lymphedema Network has stated that these guidelines are not based on comprehensive data, but rather anecdotal information (Ferguson et al., 2016). Further experiments have shown that there is no significant association between blood pressure readings and the development of lymphedema.

Relevant history:

Hypertension Hyperlipidemia type 2 diabetes mellitus peripheral artery disease carotid artery stenosis breast cancer s/p lumpectomy and subsequent completion mastectomy c/b right arm lymphedema

Relevant test results:

Carotid U/S revealing LICA stenosis >80%

Teaching points:

Importance of obtaining accurate blood pressure measurements in vasculopathic patients to ensure optimal blood pressure control. Avoid anecdotal teaching of avoiding blood pressure measurements on ipsilateral arm of mastectomy patients to avoid aggravating lymphedema.