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Photoplethysmography using a smartphone application for assessment of ulnar artery patency: a randomized clinical
Pietro Di Santo1, David T Harnett1, Trevor Simard1
1Division of Cardiology (Di Santo, Harnett, Simard, Ramirez Pourdjabbar, Youssef, Dick, Le May, Labinaz, So, Chong, Hibbert); CAPITAL Research Group (Di Santo, Harnett, Simard, Ramirez, Youssef, Moreland, Dick, Le May, Labinaz, So, Motazedian, Jung, Chong, Hibbert); Vascular Biology and Experimental Medicine Laboratory (Simard, Jung, Hibbert); Cardiovascular Research Methods Centre (Bernick, Wells), University of Ottawa Heart Institute; Department of Cellular and Molecular Medicine (Simard, Hibbert); Department of Radiology (Moreland); School of Epidemiology, Public Health and Preventive Medicine (Ramirez, Wells), University of Ottawa, Ottawa, Ont.; Division of Cardiovascular Medicine (Pourdjabbar), Sulpizio Cardiovascular Center, University of California, San Diego, CA; Icahn School of Medicine at Mount Sinai ( Chandrasekhar, Mehran), New York, NY.
Background:
Radial artery access is commonly performed for coronary angiography and invasive hemodynamic monitoring. Despite limitations in diagnostic accuracy, the modified Allen test (manual occlusion of radial and ulnar arteries followed by release of the latter and assessment of palmar blush) is used routinely to evaluate the collateral circulation to the hand and, therefore, to determine patient eligibility for radial artery access. We sought to evaluate whether a smartphone application may provide a superior alternative to the modified Allen test.
Methods:
We compared the modified Allen test with a smartphone heart rate-monitoring application (photoplethysmography readings detected using a smartphone camera lens placed on the patient's index finger) in patients undergoing a planned cardiac catheterization. Test order was randomly assigned in a 1:1 fashion. All patients then underwent conventional plethysmography of the index finger, followed by Doppler ultrasonography of the radial and ulnar arteries (the diagnostic standard). The primary outcome was diagnostic accuracy of the heart rate-monitoring application.
Results:
Among 438 patients who were included in the study, we found that the heart rate-monitoring application had a superior diagnostic accuracy compared with the modified Allen test (91.8% v. 81.7%, p = 0.002), attributable to its greater specificity (93.0% v. 82.8%, p = 0.001). We also found that this application had greater diagnostic accuracy for assessment of radial or ulnar artery patency in the ipsilateral and contralateral wrist (94.0% v. 84.0%, p < 0.001).
Interpretation:
A smartphone application used at the bedside was diagnostically superior to traditional physical examination for confirming ulnar patency before radial artery access. This study highlights the potential for smartphone-based diagnostics to aid in clinical decision-making at the patient's bedside. Trial registration: Clinicaltrials.gov, no. NCT02519491.
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