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Letters to the Editor

Is the Allen test reliable enough?

Department of Cardiovascular Surgery, Medical Faculty, Ataturk University Hospital, Erzurum, Turkey

Received 3 January 2008; accepted 17 January 2008.

^_* Corresponding author. Address: Universite Loj, 38/8, 25240 Erzurum, Turkey. Tel.: +90 442 3166333x2144; fax: +90 442 3166340. (Email: yahyaunlu{at}hotmail.com; dr_unlu{at}yahoo.com).

Key Words: Radial artery • Coronary artery bypass grafting • Ultrasonography • Allen test

I read with interest the article titled ‘Is the Allen test reliable enough?’‘ The authors enrolled in this study 145 patients who underwent [1] the Allen test, Doppler ultrasonography and digital plethysmography. They conclude that the Allen test is a good and valid screening test for the circulation of the hand.

In patients undergoing coronary artery bypass grafting surgery using radial artery grafts, is Allen's test, modified Allen's test, pulse oximetry, plethysmography, Doppler ultrasonography or magnetic resonance imaging the best method of assessing ulnar artery or collateral flow [2–4]?

Traditionally, the modified Allen's test has been used to evaluate the patency of the ulnopalmar arches. However, the modified Allen's test remains, at most, subjective especially when hand blushing is slow to occur. I stressed that a more objective test, the combination of modified Allen's test and pulse oximetry, would also be more sensitive than the modified Allen's test alone.

Barbeau et al. [3] studied 1010 patients to compare the modified Allen's test with combined plethysmography and pulse oximetry test. They found that plethysmography and pulse oximetry were to be more sensitive than the modified Allen's test, and only 1.5% of patients were not suitable candidates for the transradial approach.

In our clinic, I applied the modified Allen's test [4,5], combined with the further modification as described by Johnson et al. An oxygen saturation monitor was attached to the index finger of the appropriate hand and a baseline measurement was taken. The maximum time to confirm a negative Allen's test was considered to be 12 s. If the skin surface remained pale for longer than 12 s it indicated a positive Allen's test.

Although the clinical modified Allen's test was normal in all patients (n = 204), in three patients (1.5%) the preoperative combination of the modified Allen's test and pulse oximetry was not normal. These patients were evaluated by Doppler ultrasonography, and contraindicate radial artery harvesting. We did not harvest the radial artery in these patients; in the remaining 201 patients (98.5%) the radial artery was harvested. We did not observe any case of postoperative forearm or hand ischemia.

In conclusion, combination of modified Allen's test and pulse oximetry is a non-invasive, inexpensive and mobile procedure, which can easily be performed to evaluate the arterial supply of the hand. A negative combination of modified Allen's test and pulse oximetry safely selects patients for radial artery harvest in the majority of patients. Doppler ultrasonography predicts safe radial artery harvest in the patients with a positive combination of modified Allen's test and pulse oximetry.

References

1. Kohonen M, Teerenhovi O, Terho T, Laurikka J, Tarkka M. Is the Allen test reliable enough?. Eur J Cardiothorac Surg 2007;32:902-905.[Abstract/Free Full Text]
2. Ronald A, Patel A, Dunning J. Is the Allen's test adequate to safely confirm that a radial artery may be harvested for coronary artery bypass grafting?. Interact Cardiovasc Thorac Surg 2005;4:332-340.[Abstract/Free Full Text]
3. Barbeau GR, Arsenault F, Dugas L, Simard S, Lariviere MM. Evaluation of the ulnopalmar arterial arches with pulse oximetry and plethysmography: comparison with Allen's test in 1010 patients. Am Heart J 2004;147:489-493.[CrossRef][Medline]
4. Oettle AC, Niekerk Avan, Boon JM, Meiring JH. Evaluation of Allen's test in both arms and arteries of left and right-handed people. Surg Radiol Anat 2006;28:3-6.[CrossRef][Medline]
5. Johnson WH, Cromartie RS, Arrants JE, Wuamett JD, Holt JB. Simplified method for candidate selection for radial artery harvesting. Ann Thorac Surg 1998;65:1167.[Abstract/Free Full Text]

This article has been cited by other articles:

				M. Kohonen Reply to Agrifolio et al., Unlu, Sajja * Is the Allen test reliable enough? Eur. J. Cardiothorac. Surg., April 1, 2008; 33(4): 756 - 756. [Full Text] [PDF]

This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Add to Personal Folders Download to citation manager Author home page(s): Yahya Unlu Permission Requests Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Unlu, Y. Search for Related Content PubMed PubMed Citation Articles by Unlu, Y. Related Collections Cardiac - other Coronary disease