Normal central foveal thickness in a thousand eyes of healthy patients in sub Saharan Africa using fourier domain optical coherence tomography

Background

Optical coherence tomography provides high resolution in vivo images of the retina which are essential for diagnosis and follow up of patients with retina disorders like macula edema and exudative age-related macular degeneration. Establishing the normal range of central fovea values in our population provides vital baseline data for comparison.

Aim

To report the range of normal central fovea thickness measurements in eyes of healthy hospital patients in sub-Saharan Africa using a commercially available Fourier domain optical coherence tomography (OCT) scan.

Patients and Methods

A retrospective non-comparative review of case files of a thousand consecutive healthy patients who had retina OCT scans between January 2015 and December 2019 was done.

Results

Data from 1000 consecutive eyes of 500 healthy patients were used for the study. There were 181 females and 319 males. The mean central foveal thickness was 239.48 microns (μm), with a minimum thickness of 200.0 μm and maximum thickness of 297.0 μm. Males had significantly (P < 0.001) thicker mean CFT (mean CFT = 241.77 μm) compared with females (mean CFT = 235.43 μm). The mean CFT increased with age of participants by 0.139 μm (P < 0.001) for every year of life below 70.

Conclusion

The mean central foveal thickness (CFT) in eyes of healthy patients in our study was 239.48 μm with a range from 200 μm to 297.0 μm. Males had thicker mean CFT compared with females and there was a significant increase in mean CFT by 0.139 μm (P < 0.001) for every year of life below 70.

Are outcomes of surgery for retina detachments from giant tears worse than from other holes and tears in this era of small gauge vitrectomy and perflorocarbon use in Sub-Saharan Africa?

Aims

To report a comparison of clinical features, visual and anatomic outcomes between patients with retinal detachments from giant retinal tears (GRTs) and those from other types of holes and tears undergoing retina reattachment surgery in the same institution within the same time period in sub-Saharan Africa.

Materials and Methods

A retrospective noncomparative case series of patients undergoing primary retina detachment (RD) repair for rhegmatogenous retina detachment (RRD) at Eye Foundation Hospital Retina Institute between January 2014 and December 2018 was done.

Results

A total of 275 eyes of 275 patients met the inclusion criteria. Ages ranged from 7 to 87 years. And 81 (29.4%) eyes had giant tears were categorized as group A and 194 (70.6%) eyes had other types of tears were categorized as group B. At presentation Visual acuity in 66 eyes (79.6%) in the group A was worse than 3/60, compared to 117 eyes (60.3%) in group B. Primary anatomic success was achieved in 73 eyes (92.4%) in-group A and 157 eyes (86.7%) in group B. Final anatomic success was achieved in 75 eyes (94.9%) in group A and 164 eyes (93.2%) in group B. Good visual outcomes were achieved in 48 eyes (59.3%) in group A and 126 eyes (65.6%) in group B.

Conclusion

Good anatomic and visual outcomes can be achieved after surgery for RRD secondary to giant tears in a sub-Saharan Africa setting in this era of small gauge vitrectomy and perflourocarbon use, these outcomes are comparable to those from surgery for RRD secondary to other types of holes and tears.

The physicochemical equivalence of eight brands of amlodipine tablets in Lagos, Nigeria

BACKGROUND

Amlodipine is a dihydropyridine calcium channel antagonist that is useful in the treatment of hypertension and angina pectoris. In addition to the innovator brand of this molecule, several generic brands are marketed in Nigeria.

OBJECTIVE

To evaluate the physicochemical equivalence of eight brands of amlodipine tablets marketed in Lagos, Nigeria.

METHODS

Physicochemical properties such as identity, weight uniformity, friability, hardness test, disintegration test, dissolution test and assay of active ingredients were performed using the methods described in the British and the United States Pharmacopoeia. Ultra-violet spectrophotometric and High performance liquid chromatographic methods were used for assay of the labelled amount of amlodipine in the products.

RESULTS

All the products passed weight uniformity and disintegration tests. Only one brand failed the friability test. Two brands had mean crushing strength less than 4 kg/cm²; while only 4 brands passed dissolution test by releasing >75% of the labelled amlodipine within 45 minutes. One brand failed both assay and dissolution tests by returning less than official specifications in the general monograph for conventional tablets. In all, four of the eight sample products analyzed passed all the tests. These can be said to be physicochemically equivalent and may be clinically interchangeable or substituted.

CONCLUSION

This study further highlights the concerns over the quality of drug products marketed in a developing country.

Trends in coronary artery disease and associated risk factors in sub-Saharan Africans

It has been suggested that the prevalence of coronary artery disease (CAD) is steadily increasing in sub-Saharan Africa. To address this issue, we conducted a Medline search of English language articles on cardiovascular diseases-and specifically CAD in Africa- from 1966 to 1997. The prevalence of CAD and related complications is relatively low in most regions in Africa compared to that obtained in the economically developed countries, although the situation is rapidly changing due to trends in urbanization, changes in lifestyle, acquisition of technology and the increasing numbers of tertiary care institutions. There are variations in reported prevalence rates within the different regions, but there is an upward trend in all the regions of the sub-Saharan Africa. This trend is believed to be related to the increasing frequencies of CAD risk factors in the subcontinent.

Incidence of major cardiovascular events in black patients with normal myocardial stress perfusion study results

BACKGROUND

Previous studies have shown that the risk of major cardiovascular events at 1 year is less than 1% in patients with normal myocardial stress perfusion study results. However, the racial distribution of patients enrolled in these studies is not known. Hence, the prognostic value of normal stress perfusion study results in black patients is not well established. Our objective was to determine the incidence of major cardiovascular events in black patients with normal stress perfusion study results over a 12-month period.

METHODS AND RESULTS

We searched the nuclear cardiology database at our institution for all black patients who had normal stress perfusion study results between January 1990 and December 1996. We excluded patients with a history of coronary revascularization, valvular heart disease, cardiomyopathy, congenital heart disease, left bundle branch block, or pre-excitation syndrome. Patients were followed up for at least 12 months from the time of inclusion. A total of 592 patients were enrolled and were followed up for 18 +/- 6 months (mean +/- SD). Of these, 388 underwent treadmill exercise testing, 155 underwent dipyridamole stress testing, and the remainder underwent dobutamine stress testing. Perfusion studies were performed in all patients with thallium 201 single photon emission computed tomography imaging. During the follow-up period, 11 cardiac deaths and 7 myocardial infarctions (MIs) occurred. The incidence of cardiac deaths was 1.2% per year, and that of nonfatal MIs was 0.8% per year. The total incidence of major cardiovascular events was 2% per year. In patients who underwent treadmill exercise testing, the incidence of major cardiovascular events was 1% per year. Performance of a pharmacologic stress test and a prior MI were significantly associated with death or nonfatal MI (P <.05).

CONCLUSIONS

The overall incidence of major cardiovascular events in black patients after normal exercise perfusion study results were obtained was low (1%). However, black patients who had normal perfusion study results but underwent pharmacologic stress testing or had a history of MI were at intermediate risk. These patients require close surveillance for major cardiovascular events.

Absolute quantitation of coronary steal induced by intravenous dipyridamole

OBJECTIVE

The study was done to determine whether coronary steal (defined as an absolute decrease in perfusion from resting blood flow) is induced by intravenous (IV) dipyridamole in patients with severe coronary artery disease (CAD).

BACKGROUND

Myocardial ischemia during coronary vasodilation is usually attributed to coronary steal. However, there is limited data on the absolute magnitude of coronary steal in humans.

METHODS

Eighteen patients with multivessel CAD underwent dynamic positron emission tomography (PET) imaging with 13NH3 at rest and after infusion of IV dipyridamole. Eight myocardial sectors were analyzed per short axis slice and myocardial blood flow calculated with a two-compartment model in absolute terms.

RESULTS

Coronary steal occurred in 8 of the 18 patients. In the 8 patients with coronary steal, myocardial blood flow decreased from 90 +/- 18 ml/100 g/min at rest to 68 +/- 27 ml/100 g/min following dipyridamole in the segments with steal, and increased from 87 +/- 19 to 138 +/- 16 ml/100 g/min following dipyridamole in the segments without steal. Significant clinical correlates of coronary steal were either ST elevation or the combination of ST depression and angina.

CONCLUSIONS

Coronary vasodilation with IV dipyridamole is associated with significant reductions in blood flow to collateral-dependent myocardium consistent with coronary steal in about 45% of patients with severe CAD.

Usefulness of positron emission tomography in defining myocardial viability in patients referred for cardiac transplantation

Positron emission tomography imaging detected evidence of viability in 17 of 33 patients with evidence of infarction only on their thallium scans who were referred for transplant evaluation. Eleven of these 17 underwent revascularization with excellent outcome.