Purpose: To evaluate the relationship between nocturnal dipping in heart rates and iris and/or angle neovascularization (NV) in patients with proliferative diabetic retinopathy(PDR).
Subjects and method: One hundred fifty-one patients with PDR who underwent surgery were divided into groups based on either the presence or absence of iris and/or angle NV (NV group, 37; non-NV group, 114 patients). Pulse oximetry was conducted overnight and the heart rates were measured both before and during sleep; the resting and nocturnal heart rates and the resting-nocturnal heart rate dip ratio were calculated.
Results: The resting and nocturnal heart rates did not differ significantly between the two groups. The resting-nocturnal heart rate dip ratio was significantly lower in the NV group than in the non-NV group (p = 0.006). In the NV group, the frequency of insulin therapy (p = 0.003) and a history of coronary artery disease were significantly (p = 0.033) higher than in the non-NV group. Pearson's correlation analysis showed that only the NV group was significantly negatively correlated with the resting-nocturnal heart rate dip ratio (r = -0.18, t value = -2.2, p = 0.028).
Conclusion: In patients with PDR, the non-occurrent of nocturnal dip in heart rate may be a related factor for iris and/or angle neovascularization.