Background: Structural alterations of subcutaneous small resistance arteries, as indicated by an increased media-to-lumen ratio, are frequently present in hypertensive and/or diabetic patients, and may represent the earliest alteration observed. Furthermore, media-to-lumen ratio of small arteries evaluated by micromyography has a strong prognostic significance; however, its extensive evaluation is limited by the invasivity of the assessment, since a biopsy of subcutaneous fat is needed. Noninvasive measurement of wall-to-lumen of retinal arterioles using scanning laser Doppler flowmetry (SLDF) has recently been introduced. However, this new technique has not yet been compared to micromyographic measurement, generally considered the gold standard approach.
Methods and results: We investigated 40 individuals and patients, 24 of them were hypertensive patients and 16 normotensive individuals. All patients underwent a biopsy of subcutaneous fat during an elective surgical intervention. Subcutaneous small resistance arteries were dissected and mounted on a wire myograph, and media-to-lumen ratio was measured. In addition, an evaluation of wall-to-lumen ratio of retinal arterioles by SLDF was performed (Heidelberg Retina Flowmeter, Heidelberg Engineering). A close correlation was observed between media-to-lumen ratio of subcutaneous small arteries and wall-to-lumen ratio of retinal arterioles (r = 0.76, P < 0.001; P < 0.001, r2 = 0.57).
Conclusion: A noninvasive and easily repeatable procedure (intraobserver and interobserver variation coefficient <13%) such as an evaluation of the arterioles in the fundus oculi by SLDF may provide similar information regarding microvascular morphology compared with an invasive, accurate and prognostically relevant micromyographic measurement of media-to-lumen ratio of subcutaneous small arteries.
bClinica Chirurgica, Department of Medical and Surgical Sciences, University of Brescia
cUniversity of Molise, Campobasso
dUniversity of Ferrara
eLaboratory of Optoelectronics, Engineering Faculty, University of Brescia, Italy
Correspondence to Damiano Rizzoni, Clinica Medica, Department of Medical and Surgical Sciences, University of Brescia, c/o 2a Medicina Spedali Civili di Brescia, Piazza Spedali Civili 1, 25100 Brescia, Italy.Tel: +39 030 3905251; fax: +39 030 3384348; e-mail: firstname.lastname@example.org
Abbreviations: ACE, angiotensin-converting enzyme; SD, standard deviation; SLDF, scanning laser Doppler flowmetry
Received 12 December, 2011
Revised 17 February, 2012
Accepted 24 February, 2012