Letter by Thalhammer et al Regarding Article, “External Carotid Artery–Internal Jugular Vein Fistula: A Complication of Internal Jugular Cannulation”
To the Editor:
We read with interest the report by Sharma et al1 describing a case of an arteriovenous fistula between the external carotid artery and the internal jugular vein. We would like to comment on the presentation, which, in our opinion, raises some important questions.
Physical examination was remarkably atypical for an arteriovenous fistula of a large artery; we would expect a systolic and diastolic bruit and a palpable thrill in the area of a relevant arteriovenous fistula.2 Worsening heart failure, as in the presented patient, can only be caused by large fistulas with high-volume flow.2
An arteriovenous fistula results in a channel, which allows the high-pressure arterial blood to flow into the low-pressure venous system.3 This must result in a low-resistance flow pattern in the feeding artery, namely, the common and proximal external carotid artery and a continuous high-velocity waveform with arterialized peaks in the efferent vein.3 The presented color Doppler investigation with a low pulse-repetition frequency (15 cm/s) demonstrates aliasing in neither the systolic nor the diastolic phase, suggesting that the assumed fistula represents the first side branch of the external artery (ie, the superior thyroid artery). Venous Doppler flow pattern in the internal jugular vein shows an accentuated cardiac modulation that is consistent with congestive heart failure.
Thus, in our opinion, the presented clinical and duplex sonographic findings do not document a relevant arteriovenous fistula, and the reported diagnosis seems unlikely.
Sharma VK, Pereira AW, Ong BKC, Rathakrishnan R, Chan BPL, Teoh HL. External carotid artery-internal jugular vein fistula: a complication of internal jugular cannulation. Circulation. 2006; 113: e722–e723.
Strandness DE. Duplex Scanning in Vascular Disorders. 3rd ed. Philadelphia : Lippincott Williams & Wilkins; 2002.