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Early Increase in Retinal Arterial and Venous Blood Flow Velocities on Color Doppler Ultrasound after Acupuncture
Acupuncture is one of the oldest treatments in East-Asian countries, but its true effectiveness has been shown in only a limited number of diseases [NIH Consensus Conference Acupuncture. JAMA 1998; 280: 1518–1524]. Increased blood flow after acupuncture was demonstrated in several diseases [Watanabe M et al. Evid Based Complement Alternat Med 2012: 908 546]. Beneficial effects of acupuncture were previously recorded in some ophthalmologic diseases, for example glaucoma [Leszczynska A et al. Clin Ophthalmol 2018; 12: 1285–1291] and dry eye [Dhaliwal DK et al. Clin Ophthalmol 2019; 13: 731–740]. Color Doppler ultrasound (CDU) has previously been used to evaluate blood flow velocity changes in central retinal vessels in many ophthalmologic or systemic diseases [Venturini M et al. Transplantation 2006; 81: 1274–1277]. CDU can provide quantitative and reproducible measurements in ophthalmic vessels. In this preliminary study, blood flow velocity changes in the central retinal artery (CRA) and vein (CRV) after acupuncture were reported. This study involving human participants was in accordance with the 1964 Helsinki declaration and its later amendments or comparable ethical standards. We used CDU (Mindray-Biomed-Electronics, DC-6; Shenzhen, China; 7.5-MHz-linear probe) to examine 20 consecutive patients (11 females, 9 males; mean age 59.3 years; age range 33–83 years) affected by different ophthalmic diseases (glaucoma, maculopathy, retinitis pigmentosa, diabetic retinopathy) and enrolled due to an unsatisfactory response to conventional ophthalmic treatments. The peak systolic velocity (psv), end-diastolic velocity (edv), and resistive index (ri) in the CRAs and the maximum velocity (maxv) and minimum velocity (minv) in the CRVs of both eyes were recorded by the same radiologist with experience in ophthalmic CDU (MV). Ophthalmic CDU was performed twice: 2–3 weeks before acupuncture and then 1–2 months after the treatment. Patients were examined in supine position with closed eyelids and the Doppler signal of the CRAs and CRVs was simultaneously and easily recorded at the head optic nerve level ([Fig. 1]). A mean value for each parameter was obtained from three different measurements. The average examination time was 10 minutes. All ophthalmologic evaluations and acupuncture treatments were performed by the same ophthalmologist with experience in acupuncture for ophthalmic diseases (VV). Written consent for acupuncture was obtained from all patients. Four treatments every day for 10 consecutive days for a total of 40 treatments for each patient were performed. Every day the distal joints of 2 fingers and 2 corresponding toes were treated. According to the Boel method, every treatment was based on acupuncture of a distal joint until all 20 fingers and toes were treated 2 times. A stainless-steel needle with a size of 15 × 15 mm or 15 × 20 mm (HuanQiu, Suzhou-City, Jiangsu, China) was inserted deeply until it reached the joint capsule and held for 20 minutes. The Wilcoxon signed-rank test and SPSS v25.0.0 (IBM, Chicago, IL) were used for all statistical analyses (p-values < 0.05 considered significant). All patients tolerated the acupuncture procedure without complications. CDU showed a statistically significant increase in blood flow velocities in the CRAs (mean psv: 8.24 vs. 10.04 cm/s; edv: 1.86 vs. 2.4 cm/s; p-value < 0.00 001) and the CRVs (maxv: 4.1 vs. 5.04 cm/s; minv: 2.82 vs. 3.69 cm/s; p-value < 0.00 001) in both eyes after acupuncture. In this preliminary study, an early increase in blood flow velocities in the CRAs and CRVs after acupuncture was reported. Blood flow usually depends on blood velocity and vessel diameter, but many previous studies on ocular CDU suggest that at the retinal level an increased blood velocity reflects an increased blood flow due to the reduced dimensions and peculiar anatomy of central retinal vessels [Venturini M et al. Transplantation 2006; 81: 1274–1277]. To our knowledge, no reproducible data about the effect of acupuncture on retinal microcirculation has been previously reported. The main limitations of the present preliminary study include the heterogeneity of the patients and the lack of randomization and clinical/CDU follow-up. The actual clinical impact of this apparent beneficial effect of acupuncture on retinal microcirculation in patients not responding to conventional ophthalmic therapies requires further assessment. Further randomized studies involving a larger cohort of patients with long-term CDU and clinical follow-up will be needed to confirm these preliminary encouraging findings and to better define the real clinical impact of acupuncture in different ophthalmic diseases.
27 April 2021 (online)
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