Effect of hypertension on foveolar choroidal haemodynamics.

AIMS: To assess the effect of systemic hypertension on the choroidal circulation in subjects with a normal eye examination. METHODS: Laser Doppler flowmetry was used to determine relative choroidal blood velocity (Ch(vel)), volume (Ch(vol)), and flow (Ch(flow)) in the centre of the fovea. Measurements were obtained in 15 eyes of 15 subjects with systemic hypertension. The mean average duration of hypertension was 11 (SD 6) years. Findings obtained in these patients were compared with those of 15 eyes of 15 age matched healthy controls. All subjects had normal eye examinations. RESULTS: No significant differences in Ch(vel), Ch(vol), and Ch(flow), were found between the subjects with and without systemic hypertension despite a 17% higher perfusion pressure (PP) in patients with hypertension. No significant correlation was found between mean arterial pressure or PP and the choroidal circulatory parameters. It was estimated that there is a 90% power to detect a 35% difference in Ch(flow) between the two groups. CONCLUSION: Systemic hypertension does not seem to have a large effect on the choroidal circulation in hypertensive patients that are controlled by antihypertensive therapy. Further studies are needed to elucidate whether systemic hypertension has an effect on the choroidal circulation in patients with ocular diseases.

Effect of laser treatment for dry age related macular degeneration on foveolar choroidal haemodynamics.

AIM: Previous studies have suggested that laser photocoagulation therapy is associated with the resolution of drusen in some age related macular degeneration (AMD) patients. The main aim of the study was to determine whether low intensity laser treatment applied according to the Complications of AMD Prevention Trial (CAPT) protocol produces changes in the choroidal circulation that may help explain the mechanism leading to the resolution of drusen material. METHODS: This ancillary study included 30 CAPT patients with bilateral drusen that were treated and followed at the University of Pennsylvania. Laser Doppler flowmetry was used to measure relative choroidal blood velocity (Ch(vel)), volume (Ch(vol)), and flow (Ch(flow)) in the centre of the fovea. Measurements were obtained through a dilated pupil in both eyes of each patient at the initial CAPT visit before laser treatment was applied in one eye. Measurements were repeated in both eyes of each subject three months later. Analysis of laser Doppler measurements was performed in a masked fashion. RESULTS: In comparison to baseline, no significant differences in Ch(vel), Ch(vol), or Ch(flow) were observed three months following the application of low intensity laser according to the CAPT protocol in the untreated and treated eyes. In comparison to the untreated eyes, no significant differences were detected in the treated eyes. Based on the variability of flow measurements in the untreated eyes, the authors estimated an 85% power to detect a 15% change in relative blood flow. CONCLUSIONS: The results suggest that large alterations in choroidal blood flow do not occur at three months after low intensity laser therapy following the CAPT protocol.

The effect of pregnancy on retinal hemodynamics in diabetic versus nondiabetic mothers.

PURPOSE: To investigate retinal circulatory changes that occur during the third trimester of pregnancy in diabetic patients and control subjects. METHODS: Bidirectional laser Doppler velocimetry and monochromatic fundus photography were used to assess the retinal circulation in seven pregnant diabetic patients and 13 age-matched pregnant control subjects. Retinal venous diameter (D), maximum erythrocyte velocity (Vmax), and retinal volumetric blood flow rate (Q) were measured in one eye of each subject during the third trimester of pregnancy (DPREG, VmaxPREG, and QPREG, respectively). These measurements were repeated during the postpartum period for both diabetic patients (11+/-7 weeks postpartum) and control subjects (16+/-6 weeks postpartum; P = .203; DPOST, VmaxPOST, and QPOST). RESULTS: In control subjects, DPREG was significantly reduced by -4.5%+/-4.4% (mean percent difference +/-1 standard deviation; paired t test, P =.006) relative to DPOST. In diabetic women, DPREG was also significantly reduced by -8.1%+/-3.2% compared with DPOST (P = .001), a change that was significantly larger than that seen in control subjects (unpaired t test; P = .035). Compared with QPOS T, QPREG was reduced by -7.1%+/-14.2% (P = .123), in control subjects. In diabe tic women, QPREG was significantly decreased by -18.4%+/-9.3% compared with QPOST (P = .012). This reduction in QPREG was significantly greater in diabetic patients than in nondiabetic control subjects (unpaired t test, P = .040). No significant differences between VmaxPREG and VmaxPOST were observed in either diabetic patients (-3.1%+/-12.9%; P =.400) or control subjects (+1.9%+/-14.4%; P = .787). CONCLUSIONS: Retinal venous diameter is decreased during the third trimester of pregnancy in both diabetic and nondiabetic mothers. This decrease is significantly larger in diabetic than in nondiabetic mothers. In addition, we observed a reduction in retinal volumetric blood flow in diabetic patients during pregnancy that was significantly larger than that present in nondiabetic women. This fall in retinal volumetric blood flow in diabetic patients may exacerbate retinal ischemia and hypoxia and thus may be associated with the progression of diabetic retinopathy.

A retrospective review of blood transfusions in cancer patients with anemia.

BACKGROUND: The factors contributing to blood transfusions in patients with anemia of chronic disease are not well documented in the literature. We analyzed all blood transfusion events within a single oncology practice to determine if certain chemotherapy drugs, cancer types, or other factors necessitated more frequent transfusions. PATIENTS AND METHODS: Out of 331 patients receiving chemotherapy, 103 (31%) patients received a blood transfusion in 1995. Each of these charts was reviewed and sorted by diagnosis, treatment medications, and past transfusion and/or treatment history. Hemoglobin levels were obtained for each transfusion received in 1995. RESULTS: The average hemoglobin at time of transfusion was 7.9 g/dl. Higher hemoglobin levels at transfusion were observed for patients over the age of 60 and patients who received prior chemotherapy. Lower hemoglobin levels at transfusion were observed for patients receiving Epoetin Alfa and sarcoma patients. The average number of red blood cell (RBC) units transfused in 1995 was 5.1 per patient. More units were given to patients receiving etoposide, while fewer units were given to those receiving ifosfamide. We created a transfusion severity index (TSI) to jointly measure these two variables. CONCLUSION: The results of this study identify transfusion needs associated with certain groups of cancer patients and with certain types of chemotherapy drugs.

Effect of oral felodipine on ocular circulation.

PURPOSE: To evaluate the effects of felodipine, a calcium channel blocker, on ocular circulation. METHODS: In a double blind, randomized, crossover design, 10 volunteers received placebo or felodipine on 2 separate days. Bidirectional laser Doppler velocimetry (BLDV), laser Doppler flowmetry (LDF), and monochromatic fundus photography (MFP) were employed to assess retinal, choroidal, and optic nerve rim circulatory parameters. Measurements were obtained at baseline, 1.5, and 3 hours after dosing. Blood pressure, intraocular pressure (IOP), and heart rate were monitored, and perfusion pressure (PP) was calculated. RESULTS: In comparison to placebo, significant average percentage decreases in diastolic blood pressure (BPd; p = 0.001), mean blood pressure (BPm; p = 0.003), and perfusion pressure (PP; p = 0.003) were observed 1.5 hours following felodipine. No significant differences were observed following placebo. Retinal, choroidal and optic nerve rim circulatory parameters showed no significant changes after placebo or felodipine. A significant positive correlation between BPd and optic nerve velocity (ONve1) was observed 3 hours following felodipine (R = +0.654; p = 0.040). In contrast, no significant correlation between BPd and ONve1 was noted (R = +0.198; p = 0.583) following placebo. CONCLUSIONS: No significant change in retinal, optic nerve rim, or foveolar choroidal blood flow were observed, a factor that may be important in the treatment of systemic hypertension in patients with glaucoma.

Coronary arteriography by the percutaneous transfemoral technique in patients on intraaortic counterpulsation.

Presented are the results of the use of the transfemoral approach for coronary arteriography, as a safe alternative to the brachial approach, in evaluating patients in cardiogenic shock. Five patients, each with an intraaortic balloon pump device in operation, were evaluated. No complications were encountered using the transfemoral approach.