The role of occult hypertension in retinal vein occlusions and diabetic retinopathy

Objective: The aim of the study was to investigate whether individuals who develop retinal vein occlusion (RVO) or sudden-onset activity in otherwise quiescent diabetic retinopathy (DR) and those who have normal blood pressure (BP) or controlled hypertension according to their family physician show evidence of occult hypertension on 24-hour BP monitoring.

Methods: Patients with a new-onset RVO or DR that led to vitreous hemorrhage after a period of quiescence were identified. Informed consent was obtained, and patients were enrolled in the study if they met all of the inclusion criteria. Hypertension cut-offs were established in accordance with the Canadian Hypertension Education Program and the American Heart Association recommendations. All patients underwent a baseline BP measurement and 24-hour ambulatory BP monitoring.

Results: A total of 20 patients were enrolled in the study. Eleven (55%) were female (mean age 67.5 years). Seven patients (35%) had diabetes. Seventeen had retinal vein occlusions (85%), and 3 had sudden-onset activity in otherwise quiescent diabetic retinopathy (15%). Ten patients (50%) had no previous history of hypertension, and 10 (50%) had controlled hypertension on medications. Two patients (10%) failed to wear their BP cuff for the 24-hour duration and were excluded from the analysis. The average baseline systolic BP and diastolic BP were 133 and 78 mm Hg, respectively. Twelve patients (67%) tested positive for hypertension on their 24-hour recording, and 5 (42%) of these patients had no history of hypertension. One of 12 patients (8%) had a positive nighttime average only but a normal daytime average. Nine of the 12 patients (75%) who had a positive recording had a subsequent change made to their medications.

Conclusions: Uncontrolled hypertension is a known risk factor for the development of RVO and for vitreous hemorrhage in otherwise quiescent DR. Many of these patients may have occult hypertension that has not been detected by the currently usual standard. Twenty-four-hour ambulatory BP monitoring is a useful and potentially lifesaving clinical test, which can detect uncontrolled hypertension, especially nocturnal hypertension, in this cohort of patients. The results of this test have important treatment implications that can help prevent or minimize further systemic complications.