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D O Hodge

Publications and source records attributed to D O Hodge.

At least 19 recordsLinked to original sources
PubMed2001

Long-term survival after ablation of the atrioventricular node and implantation of a permanent pacemaker in patients with atrial fibrillation.

BACKGROUND: In patients with atrial fibrillation that is refractory to drug therapy, radio-frequency ablation of the atrioventricular node and implantation of a permanent pacemaker are an alternative therapeutic approach. The effect of this procedure on long-term survival is unknown. METHOD: We studied all patients who underwent ablation of the atrioventricular node and implantation of a permanent pacemaker at the Mayo Clinic between 1990 and 1998. Observed survival was compared with the survival rates in two control populations: age- and sex-matched members of the Minnesota population between 1970 and 1990 and consecutive patients with atrial fibrillation who received drug therapy in 1993. RESULTS: A total of 350 patients (mean [+/-SD] age, 68+/-11 years) were studied. During a mean of 36+/-26 months of follow-up, 78 patients died. The observed survival rate was significantly lower than the expected survival rate based on the general Minnesota population (P<0.001). Previous myocardial infarction (P<0.001), a history of congestive heart failure (P=0.02), and treatment with cardiac drugs after ablation (P=0.03) were independent predictors of death. Observed survival among patients without these three risk factors was similar to expected survival (P=0.43). None of the 26 patients with lone atrial fibrillation died during follow-up (37+/-27 months). The observed survival rate among patients who underwent ablation was similar to that among 229 controls with atrial fibrillation (mean age, 67+/-12 years) who received drug therapy (P=0.44). CONCLUSIONS: In the absence of underlying heart disease, survival among patients with atrial fibrillation after ablation of the atrioventricular node is similar to expected survival in the general population. Long-term survival is similar for patients with atrial fibrillation, whether they receive ablation or drug therapy. Control of the ventricular rate by ablation of the atrioventricular node and permanent pacing does not adversely affect long-term survival.

Adult↗
PubMed2001

Assessment of the exercise electrocardiogram in women versus men using tomographic myocardial perfusion imaging as the reference standard.

The exercise electrocardiogram (ECG) is widely believed to be less accurate in women, primarily due to a high prevalence of false-positive tests. The purpose of this study was to examine the relative accuracy of the exercise ECG in women versus men in 8,671 patients (3,213 women, 5,458 men) using myocardial perfusion imaging as the reference standard. More women (14%) than men (10%) had a false-positive ECG (p <0.001), but the absolute difference was relatively small. The false-negative rate was considerably lower in women (17% vs 32%, p <0.001). Compared with men, women had lower test sensitivity (30% vs 42%, p <0.001) and positive predictive value (34% vs 70%, p <0.001) but higher specificity (82% vs 78%, p = 0.002), negative predictive value (78% vs 52%, p <0.001), and accuracy (69% vs 58%, p <0.001). In patients with a false-negative exercise ECG, "high-risk" scans were less prevalent in women (12% vs 19%, p <0.001). In the smaller subset of patients referred for coronary angiography (205 women, 838 men), the false-positive electrocardiographic rate was again higher in women (13% vs 7%, p = 0.003), but neither specificity (69% vs 74%, p = NS) nor accuracy (60% vs 66%, p = NS) was different between the sexes. Thus, the percentage of patients with a false-positive exercise ECG was higher in women than men but low in absolute terms (<15%) for both sexes. Test specificity was not lower in women. These results suggest that gender should not be a major determinant for selecting stress imaging over standard treadmill testing.

Coronary Artery Disease↗
PubMed2001

Increased corneal thickness in patients with ocular hypertension.

BACKGROUND: Central corneal thickness greater than 0.520 mm causes true intraocular pressure to be overestimated when the technique of applanation tonometry is used to measure intraocular pressure. OBJECTIVE: To compare the corneal thickness measurements of patients enrolled in a study of ocular hypertension with those of age-matched control subjects with normal intraocular pressure. METHODS: Central corneal pachymetry using an optical pachymeter was performed on each study subject (n = 55) at baseline and in an independent sample of control subjects. A 2 sample, 2-tailed T test was used to compare the 2 populations. RESULTS: The patients with ocular hypertension had significantly higher mean corneal thickness measurements (mean +/- SD, 0.594 +/- 0.037 mm) than the control group (0.563 +/- 0.027 mm) (P<.001). CONCLUSION: Corneal thickness may be a confounding factor in the measurement of intraocular pressure, and this may modify the risk for progression to glaucoma in patients with ocular hypertension.

Anthropometry↗
PubMed2001

Probability of Nd:YAG laser capsulotomy after cataract surgery in Olmsted County, Minnesota.

PURPOSE: To estimate the cumulative probability of Nd:YAG laser posterior capsulotomy after cataract extraction in a geographically defined population. METHODS: Rochester Epidemiology Project databases were used to identify retrospectively all Nd:YAG laser posterior capsulotomies performed on Olmsted County, Minnesota, residents who had previously undergone cataract extraction between 1988 and 1996, inclusive. Demographic data and potential risk factors for laser, including age, sex, surgical technique, year of surgery, and intraocular lens material, were obtained by chart review or by retrieval from computer databases. The cumulative probability of Nd:YAG laser posterior capsulotomy was calculated by Kaplan-Meier estimates, and risk factors were analyzed using the Cox proportional hazards model. RESULTS: A total of 925 Nd:YAG laser posterior capsulotomies were identified after 3541 cataract extractions in 2718 patients. The cumulative probability of Nd:YAG laser posterior capsulotomy after cataract surgery was 6% (95% confidence interval = 5% to 7%) at 1 year, increasing to 38% (35% to 40%) at 9 years. Young age at the time of surgery (P =.02), polymethylmethacrylate intraocular lens material (P <.001), earlier year of surgery (P <.001), and extracapsular extraction (in comparison with phacoemulsification, P <.001) were found to increase significantly the risk of subsequent Nd:YAG laser posterior capsulotomy. Women tended to have a greater probability of Nd:YAG laser posterior capsulotomy (P =.17), but this difference was not statistically significant. CONCLUSIONS: Nd:YAG laser posterior capsulotomy was common after cataract surgery but infrequent during the first postoperative year. Prolonged follow-up is necessary in investigations of the effects of new cataract surgery technologies on the probability of capsulotomy.

Adolescent↗
PubMed2001

The long-term outcome of glaucoma filtration surgery.

PURPOSE: To determine the long-term outcome of glaucoma filtration surgery in preserving vision. Visual loss from progressive glaucomatous damage and from complications of surgery, both short and long term, were included. METHODS: A retrospective, community-based, longitudinal study of residents of Olmsted County, Minnesota, who were newly diagnosed with open-angle glaucoma between 1965 and 1980 and underwent filtration surgery in these or subsequent years through 1998. Intraocular pressure (IOP), visual acuity, visual fields, and progression to legal blindness were monitored. Kaplan-Meier analysis was used to determine the cumulative probabilities of changes in these parameters. RESULTS: 73 eyes of 49 patients underwent conventional filtration surgery. Analysis of the first eye having surgery revealed a mean preoperative IOP of 27.6 +/- 8.5 mm dropping to 16.7 +/- 5.6 mm at year one, and remaining in this range throughout follow-up (14.7 +/- 3.0 mm at 10 years; with or without use of medications). The probability of progression to blindness was 46% at 10 years after surgery, as calculated by Kaplan-Meier analysis. Eyes going blind had a postoperative IOP equal to or lower than those not becoming blind (14.0 +/- 4.4 vs. 15.4 +/- 3.0 at postoperative year 10). Eyes going blind had more advanced field loss at the time of surgery, with scotomas above and below the horizontal axis, than eyes not going blind, which had scotomas in only one hemifield. Three patients developed late bleb leaks; two patients developed endophthalmitis. The probability of undergoing cataract surgery was 37% by 10 years postoperatively, which did not differ significantly from the cohort of patients not undergoing surgery at a comparable time point. CONCLUSIONS: Filtration surgery was associated with a 54% probability of preservation of vision from progression to legal blindness at 10 years after surgery. Patients becoming blind had more advanced field loss at the time of surgery; IOP was similar between those going blind and those retaining vision.

Aged↗
PubMed2001

Estimated incidence of open-angle glaucoma in Olmsted County, Minnesota.

PURPOSE: To determine the incidence rates of open-angle glaucoma (OAG) in Olmsted County, MINNESOTA: DESIGN: Retrospective population-based estimate of incidence. PARTICIPANTS: From the medical histories of 60,666 residents of Olmsted County, Minnesota, who had ocular diagnoses during the study period, 114 subjects with newly diagnosed OAG were identified. METHODS: The database of the Rochester Epidemiology Project was used to identify all Olmsted County residents with a coded diagnosis of OAG, glaucoma suspect, or ocular hypertension during the period 1965 to 1980. Subjects newly diagnosed with and treated for OAG who also had documented clinical evidence of elevated intraocular pressure, optic nerve damage, and/or visual field loss consistent with glaucoma were included as incident cases. Population data for Olmsted County were drawn from United States Census data. Crude incidence data were adjusted to the age and gender distribution of the 1990 United States white population. MAIN OUTCOME MEASURES: Estimated incidence rates of OAG. RESULTS: The overall age- and gender-adjusted annual incidence rate of OAG in a predominantly Caucasian population is conservatively estimated to be 14.5 per 100,000 population. The rates increased with age from 1.6 in the fourth decade of life to 94.3 in the eighth decade. There was no significant difference in incidence by gender. The average annual rate of OAG in the last 2 years of the study was 27.7 compared with 12.3 before 1979. This difference is suggestive of the effect of the introduction of a new medical therapy (timolol) for OAG during the last 2 years. CONCLUSIONS: The incidence rates of OAG increase markedly with advancing age, and screening efforts should be targeted at both men and women in the older age groups. The advent of new diagnostic and therapeutic modalities can have an effect on incidence rates.

Adolescent↗
PubMed2001

Gender differences and temporal trends in clinical characteristics, stress test results and use of invasive procedures in patients undergoing evaluation for coronary artery disease.

OBJECTIVES: This study examined gender differences and temporal changes in the clinical characteristics of patients referred for nuclear stress imaging, their imaging results and subsequent utilization of coronary angiography and revascularization. BACKGROUND: Gender bias may influence resource utilization in patients with coronary artery disease (CAD). No study has analyzed gender differences and time trends in patients referred for noninvasive testing and subsequent use of invasive procedures. METHODS: Between January 1986 and December 1995, 14,499 patients (5,910 women and 8,589 men) without established CAD underwent stress myocardial perfusion imaging. The clinical characteristics, imaging results, coronary angiograms and revascularization outcomes were compared in women and men over time. RESULTS: The mean pretest probability of CAD was lower in women (45%) than in men (70%) (p < 0.001). More women (69%) than men (42%) had normal nuclear images (p < 0.001). Men (17%) were more likely than women (8%) to undergo coronary angiography (p < 0.001). Male gender was independently associated with referral for coronary angiography (multivariate model: chi-square = 16, p < 0.001) but was considerably weaker than the imaging variables (summed reversibility score: chi-square = 273, p < 0.001). Revascularization was performed in more men (46% of the population undergoing angiography) than women (39%) (p = 0.01), but gender was not independently associated with referral to revascularization. There were no significant differences in clinical, imaging or invasive variables between the genders over time. CONCLUSIONS: There was little evidence for a bias against women in this study. Women were somewhat less likely to undergo coronary angiography but were referred for stress perfusion imaging more liberally. Practice patterns remained constant over this 10-year period.

Angioplasty, Balloon, Coronary↗
PubMed2001

Comparison of Chen Medium and Optisol-GS for human corneal preservation at 4 degrees C: results of transplantation.

PURPOSE: To compare results after transplantation of donor corneas stored in Chen Medium (containing beta-hydroxybutyrate without sodium bicarbonate or chondroitin sulfate) to corneas stored in Optisol-GS medium (containing sodium bicarbonate and 2.5% chondroitin sulfate). METHODS: We performed 32 consecutive penetrating keratoplasties with donor corneas stored at 4 degrees C in either Chen Medium or Optisol-GS by random assignment. Corneal thickness measurements were made at 1 day, 1 week, 3 weeks, 2 months, and 1 year postkeratoplasty. Specular microscopic images of the donor endothelium were obtained at the beginning of storage and 2 months and 1 year postkeratoplasty. The percentage of intact epithelium 1 day after keratoplasty and the graft epithelialization time were estimated by the surgeons. Donor rim cultures were performed. RESULTS: No statistically significant differences in corneal thickness or endothelial cell loss between the corneas stored in the two media were found at any time, although differences of less than 12% cell loss or 0.09-mm thickness at 2 months or less than 25% cell loss or 0.10-mm thickness at 1 year could not be excluded with 90% certainty in this small series. The mean percentages of intact graft epithelium on day 1, 64% for Chen Medium and 65% for Optisol-GS, were not significantly different. Endothelial cell density 2 months postkeratoplasty was significantly decreased for corneas stored in both media. Endothelial cell loss at 2 months was directly correlated with storage time in both media. CONCLUSIONS: After keratoplasty, no statistically significant differences in corneal thickness, epithelial survival, and endothelial cell loss were found between corneas stored in Chen Medium and Optisol-GS. Endothelial cell loss at 2 months was significantly correlated with storage time in both media.

Adult↗
PubMed2001

Predictors of macrovascular disease in patients with type 2 diabetes mellitus.

OBJECTIVE: To assess the importance of classic and nonclassic risk factors in the development of coronary artery disease (CAD) or cerebrovascular disease (CVD) in patients with type 2 diabetes mellitus (DM). PATIENTS AND METHODS: In this community-based, prospective cohort study, quantitative measurements for cholesterol, triglycerides (TGs), glucose, and lipoprotein(a) detected as a sinking pre-beta-lipoprotein band on electrophoresis were obtained from 1968 through 1982 from 449 patients who were free of CAD and CVD but had type 2 DM. Demographic data and covariables obtained were age, body mass index, duration of diabetes, sex, smoking, and hypertension. The relationship of individual continuous factors to the development of CAD and CVD as well as multivariate models were evaluated with use of the Cox proportional hazards model. The primary outcome was to determine which risk factors are associated with development of CAD or CVD in patients with type 2 DM. RESULTS: After a mean follow-up of 13 years, 216 CAD and 115 CVD events had developed. The hazard ratio estimates with 95% confidence intervals (CIs) for CAD after multivariate analysis were significant for age, 1.45 (95% CI, 1.27-1.67); fasting glucose levels at enrollment, 1.63 (95% CI, 1.17-2.25); smoking, 1.45 (95% CI, 1.10-1.91); and TGs, 1.49 (95% CI, 1.15-1.92). The hazard ratio estimates for CVD were significant for age, 1.95 (95% CI, 1.59-2.38); hypertension, 1.89 (95% CI, 1.30-2.74); fasting glucose levels at enrollment, 1.69 (95% CI, 1.06-2.70); and smoking, 1.57 (95% CI, 1.07-2.30). CONCLUSION: In diabetic patients, age, fasting glucose levels, smoking, and TG levels are independent risk factors for development of CAD events. Age, hypertension, glucose, and smoking predicted development of CVD events.

Age Distribution↗
PubMed2000

Severe aortic stenosis with low transvalvular gradient and severe left ventricular dysfunction:result of aortic valve replacement in 52 patients.

BACKGROUND: The outcome of aortic valve replacement in patients with severe aortic stenosis, low transvalvular gradient, and severe left ventricular dysfunction is not well known. METHODS AND RESULTS: Between 1985 and 1995, 52 patients with left ventricular ejection fraction (EF) < or =35% and aortic stenosis with transvalvular mean gradient <30 mm Hg underwent aortic valve replacement. The mean (+/-SD) preoperative characteristics included EF, 26+/-8%; aortic valve mean gradient, 23+/-4 mm Hg; aortic valve area, 0.7+/-0.2 cm(2); and cardiac output, 3.7+/-1.2 L/min. Simultaneous coronary artery bypass graft surgery was performed in 32 patients (62%). Perioperative (30-day) mortality was 21% (11 of 52 patients). Ten additional patients died during follow-up. Advanced age (P=0.048) and small aortic prosthesis size (P=0.03) were significant predictors of hospital mortality by univariate analysis. By multivariate analysis, the only predictor of surgical mortality was smaller prosthesis size. The only predictor of postoperative survival was improvement in postoperative functional class (P=0.04). Postoperative functional improvement occurred in most patients. Postoperative EF was assessed in 93% of survivors; 74% demonstrated improvement. Positive change in EF was related to smaller preoperative aortic valve area and female sex. CONCLUSIONS: Despite severe left ventricular dysfunction, low transvalvular mean gradient, and increased operative mortality, aortic valve replacement was associated with improved functional status. Postoperative survival was related to younger patient age and larger aortic prosthesis size, and medium-term survival was related to improved postoperative functional class.

Adult↗
PubMed2000

Distinct hemodynamic profiles in patients with vasovagal syncope: a heterogeneous population.

OBJECTIVE: The objective was to investigate mechanisms of vasovagal syncope by identifying laboratory techniques that characterize cardiovascular profiles in patients with vasovagal syncope. BACKGROUND: The triggering mechanisms of vasovagal syncope are complex. The patient population is likely heterogeneous. We hypothesized that distinct hemodynamic profiles are definable with provocative maneuvers. METHODS: Three groups of subjects were matched for age and gender: 16 patients with a history of syncope and an inducible vasovagal response during passive tilt table testing (70 degrees, 45 min, group I), 16 with a history of syncope, negative passive tilt table testing but positive isoproterenol tilt table testing (0.05 microg/kg per min, 70 degrees, 10 min, group II), and 16 control subjects. Beat-to-beat hemodynamic functions were determined noninvasively by photo-plethysmography and impedance cardiography. RESULTS: At baseline, hemodynamic functions were not different among the three groups (supine). In response to tilt before any symptoms developed, total peripheral resistance decreased 9% +/- 14% in group I from baseline supine to tilt position but increased 27% +/- 18% in group II and 28% +/- 17% in controls (p < 0.001). Responses to isoproterenol were not significantly different between group II and controls in supine position. In response to tilt during isoproterenol infusion before any symptoms developed, total peripheral resistance decreased 24% +/- 20% in group II and increased 20% +/- 48% in controls (p = 0.002). CONCLUSIONS: Group I patients may have impaired ability to increase vascular resistance during orthostatic stress. The inability to overcome isoproterenol-induced vasodilatation during tilt is important in triggering a vasovagal response in group II patients. These data suggest that the population with vasovagal response is heterogeneous. Distinct hemodynamic profiles in response to various provocative maneuvers are definable with noninvasive, continuous monitoring techniques.

Adult↗
PubMed2000

Identification of severe coronary artery disease in patients with a single abnormal coronary territory on exercise thallium-201 imaging: the importance of clinical and exercise variables.

OBJECTIVES: The aim of this study was to determine which clinical, exercise and thallium variables can aid in the identification of three-vessel or left main coronary artery disease (3VLMD) in patients with one abnormal coronary territory (either a reversible or fixed defect) on exercise thallium testing and to test the prognostic value of these variables. BACKGROUND: Although the sensitivity of detection of coronary artery disease by thallium-201 imaging is high, the actual detection of 3VLMD by thallium tomographic images alone is not optimal. METHODS: A multivariate model for prediction of 3VLMD was developed from several clinical, exercise and thallium-201 variables in a training population of 264 patients who had one abnormal coronary artery territory on exercise thallium testing and had undergone coronary angiography. Using this model, patients were stratified into risk groups for prediction of 3VLMD. A separate validation cohort of 474 consecutive patients who were treated initially with medical therapy and who had one abnormal coronary territory were divided into identical risk groupings by the variables derived from the training population, and they were followed for a median of 7.0 years to evaluate the prognostic value of this model. RESULTS: The prevalence of 3VLMD was 26% in the training population despite one abnormal thallium coronary territory. Four clinical and exercise variables--diabetes, hypertension, magnitude of ST segment depression, and exercise rate-pressure product-were found to be independent predictors of 3VLMD. In the training population, the prevalence of 3VLMD in low-, intermediate- and high-risk groups was 15%, 22% and 51%, respectively. When the multivariate model was applied to the validation population, the eight-year overall survival rates in the low-, intermediate- and high-risk groups were 89%, 73% and 75%, respectively (p < 0.001). CONCLUSIONS: A substantial proportion of patients with one abnormal thallium coronary territory have 3VLMD with subsequent divergent outcomes based upon risk stratification by clinical and exercise variables. Consequently, the finding of only a single abnormal coronary territory by thallium-201 perfusion imaging does not necessarily confer a benign prognosis in the absence of consideration of nonimaging variables.

Coronary Angiography↗
PubMed2000

Infarct size determination by technetium 99m sestamibi single-photon emission computed tomography predicts survival in patients with chronic coronary artery disease.

BACKGROUND: The prognostic value of infarct size quantification by technetium 99m sestamibi single-photon emission computed tomography (SPECT) in patients with chronic coronary artery disease (CAD) has not been established. Methods And Results Between September 1994 and May 1995, 1323 patients with known or suspected CAD were referred for perfusion imaging for clinical reasons and had infarct size determined by quantitative SPECT imaging. Patients underwent exercise stress (61%), pharmacologic stress (37%), and rest imaging (3%). Patients were excluded if they had cardiomyopathy, valvular heart disease, or myocardial infarction within 3 weeks of the SPECT study. There were 1224 patients who formed the study group. Follow-up was 94% complete at a median of 1.9 +/- 0.4 years. Sixty-five percent of patients had no measurable infarct. Among the patients with measurable infarcts, the mean infarct size by sestamibi imaging was 15.0% +/- 14.5% of the left ventricle (25% of infarcts </=5% of the left ventricle and 25% of infarcts >/=19% of the left ventricle). By using stepwise regression analysis, age, diabetes, and hypercholesterolemia were all clinical predictors of overall death (P <.05). For cardiac death, only age and diabetes were significant. After adjusting for these clinical variables, infarct size remained an independent predictor of overall death (P =. 001) and survival free of cardiac death (P =.0002). However, when first-pass left ventricular ejection fraction was added to the models, infarct size was no longer significant. CONCLUSIONS: Infarct size determination by SPECT (99m)Tc sestamibi can predict subsequent death in patients with chronic CAD, although ejection fraction appears to have greater prognostic value.

Adult↗
PubMed2000

Specificity of the stress electrocardiogram during adenosine myocardial perfusion imaging in patients taking digoxin.

BACKGROUND: In patients taking digoxin, the exercise electrocardiogram has a lower specificity for detecting coronary artery disease. However, the effect of digoxin on adenosine-induced ST-segment depression is unknown. The purpose of this study was to evaluate the specificity of the electrocardiogram during adenosine myocardial perfusion imaging in patients taking digoxin. METHODS: Between May 1991 and September 1997, patients (n = 99) taking digoxin who underwent adenosine stress imaging with thallium-201 or technetium-99m sestamibi and coronary angiography within 3 months were retrospectively identified. Exclusion criteria included prior myocardial infarction, coronary artery angioplasty or bypass surgery, left bundle branch block, paced ventricular rhythm, or significant valvular disease. Twelve-lead electrocardiograms were visually interpreted at baseline, during adenosine infusion, and during the recovery period. The stress electrocardiogram was considered positive if there was > or =1 mm additional horizontal or downsloping ST-segment depression or elevation 0.08 seconds after the J-point compared with the baseline tracing. RESULTS: ST-segment depression and/or elevation occurred in 24 of 99 patients. There were only 2 false-positive stress electrocardiograms, yielding a specificity of 87% and positive predictive value of 92%. All 8 patients with > or =2 mm ST segment depression had multivessel disease by coronary angiography. CONCLUSIONS: ST-segment depression or elevation during adenosine myocardial perfusion imaging in patients taking digoxin is highly specific for coronary artery disease. Marked (> or =2 mm) ST-segment depression and/or ST-segment elevation is associated with a high likelihood of multivessel disease.

Adenosine↗
PubMed2000

The effect of contact lens wear on the central and peripheral corneal endothelium.

PURPOSE: To compare central and peripheral corneal endothelial cell morphometry in normal subjects and long-term contact lens wearers. METHODS: Endothelial cell density (ECD), coefficient of variation of cell area (CV), and percentage of six-sided cells were measured by contact specular microscopy in the corneal center and temporal periphery of both eyes of 43 long-term contact lens wearers and in 84 normal subjects who had never worn contact lenses. The latter group included 43 age- and sex-matched controls for the contact lens wearers. ECDs were corrected for magnification changes due to corneal thickness. RESULTS: Central ECD (2,723+/-366 cells/mm2, mean +/- SD) was significantly higher than peripheral ECD (2,646+/-394 cells/mm2) for the normal group (p = 0.01) but not for the contact lens wear group (2,855+/-428 cells/mm2 central, 2,844+/-494 cells/mm2 peripheral, p = 0.84). Peripheral CV was significantly higher than central for normal subjects and contact lens wearers and was significantly higher in both center and periphery in contact lens wearers than in controls. Central percentage of six-sided cells was significantly higher than peripheral for normal subjects and contact lens wearers and was lower in both center and periphery in contact lens wearers than in controls. CONCLUSIONS: Central ECD was significantly higher by 3% than peripheral ECD in normal subjects, but not in contact lens wearers. The results suggest that contact lens wear causes a mild redistribution of endothelial cells from the central to the peripheral cornea. A reversal of this redistribution after contact lens wear is discontinued for refractive surgery could mask mild central endothelial damage from the refractive procedure.

Cell Count↗
PubMed2000

In vitro comparison of Chen medium and Optisol-GS medium for human corneal storage.

PURPOSE: To compare paired human corneas after storage at 4 degrees C in Chen medium (CM) and Optisol-GS medium (OM) for 7, 10, 14, and 21 days. METHODS: One cornea of each pair from nine human donors was randomly stored in either CM or OM, with its mate cornea stored in the other medium. Three pairs of corneas were stored for 7 days and two pairs each were stored for 10, 14, and 21 days at 4 degrees C. Baseline corneal thickness measurements and endothelial photographs were obtained with a specular microscope. Corneal thickness measurements were also taken on days 7, 10, 14, and 21 of storage. At the end of storage, the corneas were warmed 2 hours before endothelial photographs were taken and were then placed in fixative. A corneal endothelial analysis system was used to compare changes in endothelial size and shape after storage. After fixation, the corneal endothelium was examined by scanning electron microscopy (SEM), and TdT-dUTP terminal nick-end labeling (TUNEL) assays with 4'6-diamidino-2-phenylindole (DAPI) counterstaining were performed on tissue sections of each cornea. A laser scanning confocal microscope and an automated digital analysis system were used to detect the presence of TUNEL-positive apoptotic cells in each cell layer and to determine keratocyte densities. RESULTS: Mean corneal thickness at 0, 7, 10, 14, 21 days of storage was 0.69 +/- 0.05 mm, 0.69 +/- 0.06 mm, 0.73 +/- 0.08 mm, 0.87 +/- 0.04 mm, and 0.87 +/- 0.03 mm, respectively, for CM and 0.65 +/- 0.06 mm, 0.59 +/- 0.07 mm, 0.63 +/- 0.03 mm, 0.60 +/- 0.03 mm, and 0.69 +/- 0.02 mm, respectively, for OM (p < 0.0001). The mean decrease in endothelial cell density at the end of the 7-, 10-, and 14-day storage periods was 11 +/- 10% for the CM corneas and 5 +/- 5% for the OM corneas (p = 0.18). SEM showed an intact endothelial monolayer in all corneas. The mean percentages of TUNEL-positive cells in epithelium, stroma, and endothelium of CM-stored corneas were 4 +/- 4%, 2 +/- 3%, and 0.1 +/- 0.3%, respectively, and did not differ from the OM-stored corneal values of 4 +/- 3%, 2 +/- 4%, and 0.9 +/- 1.5%. The percentage of TUNEL-positive cells did not increase with storage time. Keratocyte density was 368 +/- 130 cells/mm2 for CM-stored corneas and 447 +/- 96 cells/mm2 for OM-stored corneas (p = 0.13). CONCLUSIONS: Corneas stored in CM were thicker during storage than those stored in OM. The two storage media did not differ with respect to endothelial cell loss during storage or to the percentage of TUNEL-positive cells or keratocyte density at the end of the storage period.

Adult↗
PubMed2000

Is rest or exercise hypertension a cause of a false-positive exercise test?

STUDY OBJECTIVES: To determine if a history of hypertension or an exaggerated rise in exercise systolic BP is associated with a false-positive exercise ECG. DESIGN, SETTING, AND PATIENTS: Retrospective analysis of the associations between exercise-induced ST-segment depression and a history of hypertension, exercise systolic BP, and several other clinical and exercise test variables. Among 20,097 patients referred for exercise tomographic thallium imaging in a nuclear cardiology laboratory at a tertiary care center, 1,873 patients met inclusion criteria for this study, which included no history of myocardial infarction or coronary artery revascularization, a normal resting ECG, and normal exercise thallium images. RESULTS: False-positive ST-segment depression occurred in 20% of the population. A history of hypertension was actually associated with a lower likelihood of ST-segment depression (odds ratio, 0.70; 95% confidence interval [CI], 0.55 to 0.89; p = 0. 004). A higher peak exercise systolic BP was associated with a higher likelihood of ST-segment depression (odds ratio, 1.08 for each 10-mm Hg increase in systolic BP; 95% CI, 1.03 to 1.14; p < 0. 001). However, the association between peak exercise systolic BP and ST-segment depression was so weak that this measurement could not be predictive in the individual patient (R(2) = 0.2%). For every 20-mm Hg increase in peak exercise systolic BP, the percentage of patients with ST-segment depression increased by only 3%. CONCLUSIONS: In patients with normal resting ECGs, we conclude the following: (1) a history of hypertension is not a cause of a false-positive exercise test, and (2) higher exercise systolic BP is a significant but weak predictor of ST-segment depression.

Blood Pressure↗