Posterior-to-anterior tibial artery peak systolic velocity ratio (PT:AT) showed a moderate-to-strong positive correlation with foveal avascular zone enlargement (r = 0.471, p = 0.0086), while ankle-brachial index showed no significant association (r = -0.024, p = 0.901) in adults with type 2 diabetes.
Observational (n=30)
No
Does the peak-systolic velocity of posterior/anterior tibial artery ratio (PT:AT) correlate better with foveal avascular zone enlargement than ABI in patients with type 2 diabetes?
Velocity-based tibial hemodynamics (PT:AT) correlate significantly with retinal microvascular damage in type 2 diabetes, unlike traditional pressure-based ABI, suggesting its potential utility as a complementary screening tool.
Effect estimate: r 0.471 for PT:AT; r -0.024 for ABI (95% CI 95% CI [0.13, 0.71] for PT:AT; 95% CI [-0.38, 0.34] for ABI)
Absolute Event Rate: 0.471% vs -0.024%
p-value: p=0.0086 for PT:AT; 0.901 for ABI
(1) Background: Diabetic retinopathy and peripheral arterial disease co-occur through shared endothelial pathophysiology. Ankle-brachial index (ABI), the standard peripheral screening tool, demonstrates poor sensitivity (35%) in diabetic cohorts due to medial arterial calcification. We comparatively assessed the association of peak-systolic velocity of posterior/anterior tibial artery ratio (PT:AT) versus that of traditional pressure-based (ABI) with foveal avascular zone (FAZ), a marker of retinal ischemia, and thus hypothesized that PT:AT would demonstrate stronger association with FAZ compared to ABI in our cohort. (2) Methods: Cross-sectional pilot study of 30 type 2 diabetes mellitus patients. We aimed to enhance the robustness of our results using five convergent statistical methods. (3) Results: PT:AT showed strong association with FAZ (r = 0.471, p = 0.0086, 95% CI 0.13, 0.71), with convergent evidence across all five analytical methods. ABI showed no effect (r = −0.024, p = 0.901, 95% CI −0.38, 0.34). We showed that velocity-based metrics identify microvascular dysfunction, whereas the pressure-based ABI does not. The mediation analysis showed that the relation of PT:AT to FAZ is not significantly mediated by the resistivity index of ophthalmic artery. (4) Conclusions: In this pilot study, velocity-based tibial hemodynamics showed a stronger cross-sectional relationship with retinal microvascular damage compared to pressure-based ABI. These preliminary findings suggest PT:AT assessment may complement ABI screening in diabetic foot clinics to identify patients requiring intensive retinal surveillance. Multicenter validation is required before clinical implementation.
Ladea et al. (2026) conducted an observational in Adults with type 2 diabetes mellitus diagnosed according to ADA criteria with disease duration >5 years and moderate glycemic control (mean HbA1c 7.2%), enrolled from a diabetic foot clinic in Romania, with visual acuity 0.1 or better, without type 1 diabetes, no prior vitreoretinal surgery or severe peripheral vascular disease precluding ultrasound (n=30). Assessment of posterior-to-anterior tibial artery peak systolic velocity ratio (PT:AT) vs. Ankle-brachial index (ABI) was evaluated on Correlation between PT:AT ratio and foveal avascular zone (FAZ) area as marker of retinal microvascular damage (r 0.471 for PT:AT; r -0.024 for ABI, 95% CI 95% CI [0.13, 0.71] for PT:AT; 95% CI [-0.38, 0.34] for ABI, p=0.0086 for PT:AT; 0.901 for ABI). Posterior-to-anterior tibial artery peak systolic velocity ratio (PT:AT) showed a moderate-to-strong positive correlation with foveal avascular zone enlargement (r = 0.471, p = 0.0086), while ankle-brachial index showed no significant association (r = -0.024, p = 0.901) in adults with type 2 diabetes.