Original title: Trans-Radial Coronary Catheterization and Intervention Across the Whole Spectrum of Allen’s test Results. Reference: Marco Valgimigli et al. J Am Coll Cardiol. 2014. Epub ahead of print.
Radial access is associated with a chance of occlusion of the vessel in between 0.8 % and 30 % according to different series. Given this fact, the Allen test had been historically recommend assessing palmar arches permeability to avoid ischemic complications, which resulted in the exclusion of up to 27 % of patients that could have received radial access. If the Allen test can or cannot predict ischemic complications still controversial and indeed many centers worldwide are not performing it. The RADAR study (RADial approach be denied to patients with negative Allen’s test Results) was designed to evaluate the safety of the radial access in patients with abnormal Allen test (> 10 seconds) or intermediate (6-10 seconds) compared with those with normal test (< 5 seconds).
In addition to the test, patients were classified into 4 types according to the pulse oximetry plethysmography: A) Curve is not modify after occlusion of the radial, B) the curve flattens, C) curve disappears but recovers within 2 minutes and D) the curve is not recovered after 2 minutes.
The lactic acid concentrations was also measured in the thumb before the procedure, immediately after removing the introducer, and then the bandage release, a day later, one-month and one year. 203 patients were included of whom 83 had a normal Allen test, 60 intermediate and 60 abnormal results. The primary end point consisting of the value of lactic acid post procedure did not change significantly between the three groups (1.85 ± 0.93 mmol/L normal Allen, 1.85 ± 0.66 mmol/L intermediate Allen and 1.97 ± 0.71mmol/L abnormal Allen; p = 0.59). So did the rest of the cuts in time. An increase of about 20% of the lactic acid concentration in regards to baseline was observed immediately after bandage release, although this was independent of the Allen test.
One day after the procedure the loss of radial pulse was observed in 5 patients (1 with abnormal Allen test) found completely asymptomatic and objectifying them all, from the ulnar collateral circulation by Doppler.
Conclusion
This study provides information to change the paradigm that a normal Allen test is a requirement for radial access. No clinical or sub clinical signs of ischemia were observed in hand after catheterization performed with abnormal Allen test.
Editorial comment
The findings of this study suggest that the permeability of the palmar arches is very dynamic and there is a pool of collateral that can be recruited after catheterization in those with abnormal Allen test. In addition to assessing symptoms and the level of lactic acid (they used a similar method to test blood glucose) this paper conducted a discomfort test and a dynamometer strength test in the hand concluding that the Allen test could not predict the result of either of these tests. The MATRIX trial (Minimizing Adverse haemmhorragic events by TRansradial access
site and systemic Implementation of angioX) is currently recruiting patients to definitively answer the question of whether we should continue to perform the Allen test.
SOLACI.ORG
