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Biomedical subjects

P J Kertes

Publications and source records attributed to P J Kertes.

At least 19 recordsLinked to original sources
PubMed2001

Prevalence of factor V Leiden and activated protein C resistance in central retinal vein occlusion.

PURPOSE: Factor V Leiden is a common inherited mutation that is a significant risk factor for deep vein thrombosis. It results in resistance to activated protein C (APC). The association between factor V Leiden and central retinal vein occlusion (CRVO) remains controversial. This study was designed to determine the prevalence of APC resistance and the factor V Leiden mutation in patients with CRVO in a controlled study. METHODS: The study was designed as a case control study conducted in a tertiary care retina practice. The prevalence of APC resistance and factor V Leiden was determined by genetic testing of blood samples obtained from patients with CRVO and clinic control patients. RESULTS: Factor V Leiden was identified in 2.3% of patients with CRVO and 3.5% of clinic control patients. There was no significant association between the presence of factor V Leiden and CRVO (odds ratio, 1.13; 95% confidence interval, 0.65-1.98; P = 0.66). CONCLUSION: Factor V Leiden does not appear to be associated with CRVO. Routine screening of patients with CRVO does not appear to be warranted.

Activated Protein C Resistance↗
PubMed1999

Symptomatic and asymptomatic visual loss in patients taking vigabatrin.

PURPOSE: To investigate the clinical, perimetric, and electrophysiologic findings in patients with visual field loss on long-term treatment with the antiepileptic medication vigabatrin. DESIGN: Consecutive observational case series. PARTICIPANTS: Forty-one consecutive subjects taking vigabatrin referred for screening ophthalmologic assessment were studied. Twelve subjects with evidence of peripheral visual field constriction are presented. METHODS: Twelve subjects with evidence of peripheral visual field constriction on 60-4 perimetry underwent central 30-2 and blue-on-yellow (B/Y) perimetry, as well as electroretinography (ERG), electro-oculography (EOG), and visual-evoked potential (VEP) testing. MAIN OUTCOME MEASURES: Visual acuity; fundus abnormalities; visual field loss; and ERG, EOG, or VEP abnormalities were the main outcome measures. RESULTS: Eight of the 12 subjects with constricted visual fields were asymptomatic. The central 30-2 perimetry demonstrated bilateral visual field constriction in 9 of 12 patients and the B/Y perimetry in 8 of 9 patients tested. Of the ten patients tested electrophysiologically, four had abnormal ERGs, five had abnormal EOGs, and three had delayed VEPs. CONCLUSIONS: The incidence of visual field constriction in patients taking vigabatrin may be higher, and asymptomatic visual field loss more common, than reported previously. The authors postulate a possible Muller cell dysfunction in the peripheral retina. Patients taking vigabatrin should have regular peripheral visual field examinations.

4-Aminobutyrate Transaminase↗
PubMed1999

Management of submacular hemorrhage with intravitreal sulfur hexafluoride: a pilot study.

BACKGROUND: Some success has been reported with the intravitreal use of tissue plasminogen activator (tPA) and perfluoropropane gas in the management of large submacular hemorrhages. However, the dosage of tPA that has been used (100 micrograms) has a narrow margin of safety, and it remains to be shown that intravitreal tPA can cross the retina and effect subretinal clot lysis. We carried out a pilot study to evaluate the efficacy of intravitreally administered sulfur hexafluoride (SF6) gas alone in the management of large submacular hemorrhages secondary to age-related macular degeneration (AMD). METHODS: Three patients with large submacular hemorrhages secondary to AMD seen at a university-affiliated teaching hospital in Ottawa were treated with an intravitreal injection of 0.6 mL of SF6 gas. They were instructed to assume a prone position for 7 to 10 days. The patients were followed 3, 7, 14 and 28 days after the procedure and monthly thereafter for at least 6 months. Colour photography and fluorescein and indocyanine green angiography were performed immediately before and 2 weeks after the procedure and, thereafter, at the discretion of the treating ophthalmologist. RESULTS: In all three cases significant inferior displacement of the submacular blood was observed. Two patients showed an improvement of vision from counting fingers to 20/70 and to 20/200. In one case the submacular blood was displaced such that laser photocoagulation of a juxtafoveal choroidal neovascular membrane became possible. INTERPRETATION: The results suggest that intravitreally administered SF6 alone may have a role in the management of selected cases of neovascular AMD complicated by significant submacular hemorrhage. These results call into question the utility of adjunctive intravitreal tPA in such cases.

Fluorescein Angiography↗
PubMed1998

Internal resection of posterior uveal melanomas.

AIMS: To evaluate the safety and efficacy of internal resection in the treatment of malignant melanoma of the choroid. METHODS: 32 consecutive patients with histopathologically proved malignant choroidal melanomas were treated with internal resection. 29 of the 32 (90.6%) tumours were within 2 disc diameters of the optic nerve or fovea. The surgery was performed at two university centres by one of the authors. Follow up was between 1 and 85 months (mean 40.1 months). RESULTS: Three patients developed distant metastases and died of malignant melanoma (metastatic and mortality rate 9.4%). In one case, distant metastases developed in association with an intraocular recurrence. There have been no other intraocular recurrences. The most common postoperative complication was vitreous haemorrhage, which occurred in 12 patients (37.5%); cataract occurred in eight eyes; and three patients developed retinal detachment postoperatively. Three of the operated eyes have been enucleated (9.4%); a total of four (12.5%) have lost light perception. 10 patients (31.2%) had visual acuities of 6/60 or better and 18 of 32 (56.3%) were between 6/120 and light perception. CONCLUSION: These data suggest that the internal resection of posterior uveal melanomas is a reasonable globe saving management option. This treatment modality is particularly well suited to elevated tumours in close proximity to the optic nerve or fovea.

Adult↗
PubMed1997

The management of giant retinal tears using perfluoroperhydrophenanthrene. A multicenter case series. Vitreon Collaborative Study Group.

OBJECTIVE: The purpose of the study was to determine the predictors of success and evaluate the use of perfluoroperhydrophenanthrene as an intraoperative and postoperative tool in the management of giant retinal tears in a multicentered collaborative study. DESIGN: Multicentered prospective case series. PARTICIPANTS: Twenty-three centers consecutively enrolled 162 eyes of 161 patients with retinal tears 90 degrees or greater in circumferential extent. INTERVENTION: Perfluoroperhydrophenanthrene was used as an intraoperative surgical adjunct in all cases and left after surgery in 16 eyes (9.9%). MAIN OUTCOME MEASURES: Retinal reattachment and visual acuity. RESULTS: Intraoperative reattachment was achieved in 158 eyes (97.5%); 147 eyes (90.7%) remained attached at their most recent follow-up. Seventy-nine eyes (48.8%) experienced an improvement in their visual acuity, 26 eyes (16.0%) remained unchanged, and 57 (35.2%) worsened. Recurrent retinal detachment occurred in 80 patients (49.4%). Other significant postoperative complications included cataract formation in 20 (39.2%) of 51 eyes, macular pucker in 12 (7.4%), corneal decompensation in 10 (6.2%), and hypotony (intraocular pressure equal to or less than 5 mmHg) in 9 (5.6%). A chi-square analysis of preoperative characteristics showed that hypotony (P = 0.007), macular detachment (P = 0.020), a history of cataract extraction (P = 0.003), poor visual acuity (P = 0.000), giant tear extent greater than 180 degrees (P = 0.004), and higher grade proliferative vitreoretinopathy (P = 0.000) all predicted a poor visual outcome. Vitreon (Vitrophage, Inc., Lyons, IL) was left in 16 eyes (9.9%) for an extended postoperative retinal tamponade for between 3 and 1034 days (mean, 87.2 days). The Vitreon was well tolerated, and these eyes experienced a similar outcome and rate of retinal reattachment to the rest of the group. CONCLUSIONS: Vitreon is a safe and useful adjunct to pars plana vitrectomy in the management of giant retinal tears and may, additionally, be the perfluorocarbon liquid that can be used most safely as a temporary postoperative tool for extended retinal tamponade, reinforcing its role as a useful adjunct in the management of these complex retinal detachments.

Adolescent↗
PubMed1997

Management of dry retinal folds.

BACKGROUND: To describe the surgical technique used in the management of two cases of dry retinal folds which occurred following retinal detachment surgery. METHODS: Two patients with persistent dry retinal folds. RESULTS: Patients underwent complete vitrectomy and membrane peeling, followed by injection of perfluorocarbon liquid. The retina was prodded and massaged flat with a silicone-tipped cannula under the perfluorocarbon liquid. The folds disappeared and the retina remained flat. CONCLUSION: The use of gentle manipulation under heavy perfluorocarbon liquids is an effective strategy for managing longstanding dry posterior retinal folds.

Adult↗
PubMed1995

Toxicity of intravitreal interferon alpha-2b in the rabbit.

OBJECTIVE: To investigate the toxicity of single doses of intravitreally administered interferon alpha-2b in the New Zealand white albino rabbit. INTERVENTIONS: One eye each of six rabbits received an intravitreal injection of 1000, 10,000, 100,000, 500,000, 1 million or 2 million units of interferon alpha-2b reconstituted in 0.1 mL of balanced salt solution. The fellow eye of the first three rabbits received an intravitreal injection of the same volume of balanced salt solution. OUTCOME MEASURES: Media opacities, toxic effects to the retina, optic nerve or other ocular structures. RESULTS: The injection of 2 million units of interferon alpha-2b elicited an immediate dense vitreous haze that largely cleared within 24 hours as well as numerous intraretinal hemorrhages that were no longer visible 7 days after injection. Histopathological study of this eye 14 days after injection showed a diffuse mixed inflammatory cell infiltrate with retinal vacuolation and ganglion cell dropout. In the remaining eyes, to dosages of 1 million units, the agent produced no clinically or pathologically evident toxic ocular effects. CONCLUSIONS: Interferon alpha-2b appears to be safe and well tolerated up to dosages of 1 million units.

Animals↗
PubMed1994

Radiofrequency catheter ablation. A new, curative therapy for supraventricular tachyarrhythmias.

Radiofrequency catheter ablation is a major advance in the treatment of tachyarrhythmias, particularly SVT. It offers the chance of permanent cure, without the need for major surgery, for a condition that is usually life-long and necessitates years of drug treatment. At present the risks of RF ablation are low, although not insignificant; potential subjects must be given the opportunity of making an informed choice. With improvements in technique and equipment, the indications for this procedure are likely to widen.

Catheter Ablation↗
PubMed1993

Cost effectiveness of radiofrequency catheter ablation in the treatment of symptomatic supraventricular tachyarrhythmias.

BACKGROUND: The recent advent of radiofrequency (RF) catheter ablation as a curative therapy for supraventricular tachyarrhythmias has challenged the role of long term drug treatment, which is essentially a palliative therapy. To date, however, no data have been published on the cost-effectiveness of RF ablation as compared with drug treatment in the Australian setting. AIMS: The study aimed to compare actual and projected costs of these two treatment options in a consecutive group of patients having RF ablation as treatment for symptomatic tachyarrhythmias. METHODS: The cost effectiveness of RF catheter ablation was assessed in 26 patients having RF ablation, using a hypothetical model of continued drug therapy in the same group of patients. A 'cost saving' criterion was used for cost effectiveness. Actual costs for the RF ablation and for continued drug therapy were based on data from medical records and from the answers to a detailed patient questionnaire. Analysis included costs of prior diagnostic electrophysiology (EP) study (17/26 patients), general anaesthesia (GA: 20/26 patients), post-ablation echocardiography (10/26 patients), and late follow-up EP study (7/26 patients). The in-hospital stay for the RF ablation was two days in all cases, and no patient required implantation of a permanent pacemaker. The RF ablation procedure was successful in 23/26 patients (88.5%) with late recurrence of tachycardia in one patient. After a median follow-up of nine months, 22/26 patients no longer require antiarrhythmic drug therapy. RESULTS: The mean per patient cost of RF ablation was $4067 in the study group. This reduces to $2546 if prior EP study and GA are excluded. The mean per patient cost of continued medical therapy was $700 per year. Extrapolating over 20 years and allowing for an annual 5% inflation factor, RF ablation becomes cost saving in 5.5 years (3.8 years if prior EP and GA are excluded). Over 20 years, continued drug therapy would be four to five times more expensive than RF ablation in the patient study group. We consider RF ablation to be a cost-effective alternative to long term drug therapy in patients with supraventricular tachyarrhythmias.

Adolescent↗