Adaptive optics assisted visualization of thickened retinal arterial wall in a patient with controlled malignant hypertension
Received 30 July 2014
Accepted for publication 3 September 2014
Published 6 October 2014 Volume 2014:8 Pages 2041—2043
Checked for plagiarism Yes
Review by Single anonymous peer review
Peer reviewer comments 3
Editor who approved publication: Dr Scott Fraser
Shigeta Arichika, Akihito Uji, Nagahisa Yoshimura
Department of Ophthalmology and Visual Sciences, Graduate School of Medicine, Kyoto University, Kyoto, Japan
Purpose: We aimed to visualize the retinal arterial wall thickness, assisted by noninvasive adaptive optics scanning laser ophthalmoscopy (AO-SLO).
Methods: The arterial wall thickness was measured and compared between one normal subject and one patient suffering from malignant hypertensive retinopathy.
Results: Increased arterial wall thickness was revealed with a newly developed AO-SLO system, in a retinal artery of 1-papilla diameter temporal inferior to the optic disc. The average wall thickness, with hypertension, was 18.7 µm, and the wall-to-lumen ratio was 0.44, both bigger than normal.
Conclusion: AO-SLO enabled us to evaluate the retinal wall thickness in the hypertensive patient. The arterial walls were thickened compared with normal. AO-SLO may facilitate future noninvasive study of arterial walls in human medicine.
Keywords: wall thickness, AO-SLO, hypertensive retinopathy
The Keith–Wagener1 and Scheie2 classification schemes are widely used for staging of hypertensive and arteriosclerotic changes, by categorizing vascular appearance on ophthalmoscopic examination or color fundus photography. Recently, direct visualization of the arterial walls in the retina using adaptive optics scanning laser ophthalmoscopy (AO-SLO) has been reported and is expected to provide valuable information on hypertensive and sclerotic arterial changes. Herein, we illustrate a case of malignant hypertension in which AO-SLO images clearly demonstrated a thickened retinal arterial wall.
A 33-year-old woman complaining of decreased vision in the right eye was referred to our institution. Her visual acuity was 20/50 in the right eye and 20/20 in the left eye. Fundus examination revealed retinal hemorrhage, “cotton-wool” spots, and papilledema in both eyes, with macular edema in the right eye (Figure 1). Spectral-domain optical coherence tomography (SD-OCT) (Spectralis®; Heidelberg Engineering, Heidelberg, Germany) showed serous retinal detachment and hyperreflective foci, which represented precursors of hard exudate in the retina. Her blood pressure was 234/134 mmHg, and blood tests showed elevated serum creatinine level (14 mg/dL). Moreover, abdominal magnetic resonance imaging (MRI) revealed bilateral renal atrophy. She was diagnosed with malignant nephrosclerosis, malignant hypertension, and hypertensive retinopathy. Hemodialysis and antihypertensive treatment were started immediately. Three months later, her blood pressure had decreased to 115/69, and abnormal findings, except for minimal deposition of hard exudate in the fundus, had resolved. Visual acuity in the right eye had improved to 20/16. Increased arterial wall thickness was revealed with an AO-SLO system (Canon Inc., Tokyo, Japan) in a retinal artery of 1-papilla diameter temporal inferior to the optic disc in the right eye (Figure 2). The average wall thickness was 18.7 μm, and the wall-to-lumen ratio was 0.44.
Figure 2 Adaptive optics scanning laser ophthalmoscopy (AO-SLO) images of thickened retinal arterial wall.
Adaptive optics scanning laser ophthalmoscopy
We developed a novel AO-SLO system with a high wavefront correction efficiency, using a dual liquid-crystal phase modulator (LCOS-SLM, model X10468-02; Hamamatsu Photonics, Hamamatsu City, Japan). The AO-SLO videos were acquired at 32 frames/second in an area covering the parafovea. The scan area was 2.8°×2.8° at the retina, with a sampling of 400×400 pixels. All AO-SLO imaging was performed with the optical focus adjusting on the vessel wall to be described clearly.
AO-SLO is a useful modality for noninvasive demonstration of, not only photoreceptor cells, but also, blood flow, blood corpuscles, and the retinal nerve fiber layer. Recently, visualization of arterial wall thickness in the retina has been reported.3 In the current report, AO-SLO yielded clear images of a vascular wall in a patient with controlled malignant hypertension and revealed thickening of the vessel wall compared with a normal volunteer of the same age as the patient. The wall-to-lumen ratio reported here concurred with previous results obtained using Doppler flowmetry by Ritt et al4 and Rizzoni et al5 who reported wall-to-lumen ratios of 0.28 and 0.26, respectively, for normotensive subjects, and of 0.36 and 0.37, respectively, for hypertensive patients. The changes in arterial structure in hypertension are considered to result from mechanoadaptive processes to maintain optimum levels of wall tension or stress. Although blood pressure was well controlled in this patient, the arterial wall thickening suggested that blood vessel wall changes were irreversible to a certain extent. AO-SLO may facilitate future noninvasive study of arterial walls, in human medicine. In the near future, we intend to conduct further studies using an appropriate number of patients.
This work was supported in part by the Innovative Techno-Hub for Integrated Medical Bio-imaging Project of the Special Coordination Funds for Promoting Science and Technology, from the Ministry of Education, Culture, Sports, Science and Technology, Japan.
Nagahisa Yoshimura received lecture fees and research funding from Canon. The authors report no other conflicts of interest in this work.
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