Nicoladoni–Branham sign

Nicoladoni–Branham sign is a clinical sign in medicine that is used to identify the presence of an arteriovenous fistula, which is an abnormal connection between an artery and a vein. This sign is named after Carl Nicoladoni, an Austrian surgeon, and Harris Branham, an American physician, who independently described the phenomenon.

Overview

The Nicoladoni–Branham sign is observed when pressure is applied to the area of the arteriovenous fistula, leading to a decrease in heart rate. This occurs due to a reduction in the preload on the heart as a result of the decreased return of venous blood, which in turn is caused by the occlusion of the fistula. The heart compensates for the reduced volume by decreasing its rate, a reflex action mediated by the baroreceptors.

Clinical significance

The presence of the Nicoladoni–Branham sign is significant in the diagnosis of arteriovenous fistulas, which can occur due to congenital reasons, trauma, or as a complication of medical procedures. Identifying an arteriovenous fistula is crucial as it can lead to various complications, including heart failure, due to the increased workload on the heart and the disruption of normal blood flow patterns.

Diagnosis

In addition to the Nicoladoni–Branham sign, the diagnosis of an arteriovenous fistula typically involves imaging studies such as Doppler ultrasound, CT angiography, or MRI angiography to visualize the abnormal connection and assess its impact on blood flow. Physical examination may also reveal a palpable thrill or audible bruit over the site of the fistula.

Treatment

The treatment of arteriovenous fistulas depends on their size, location, and the symptoms they cause. Options include monitoring small, asymptomatic fistulas, or interventions such as surgical repair, endovascular techniques like coil embolization, or the placement of stents to close the fistula and restore normal blood flow.

See also

• Arteriovenous malformation
• Cardiovascular system
• Heart rate