Editorial

Gallstone disease: a call to awareness in Subsaharan Afric

Aortic arch origin of the vertebral artery may have clinical implications

No Abstrac

Sex differences in diameter of the coronary sinus ostium: Correlation with weight of the heart

Diameter of the coronary sinus ostium is important in the designing of cannulation devices used in cardiac resynchronization  therapy and percutaneous mitral valve annuloplasty. Population variation of the diameter may account for the failure rate of these procedures. Studies of the coronary sinus ostium from African populations are scarce and altogether absent for Kenya. Therefore, this study aimed at determining sex differences in the diameter of coronary sinus ostium and its correlation with the weight of the heart. Seventy-four hearts of adult black Kenyans [43 male, 31 females; age range 20 – 70 years] obtained during autopsy at the Department of Human Anatomy, University of Nairobi, Kenya were weighed. The coronary sinus ostium was identified and its   transverse and supero-inferior diameters measured in millimeters. The measurements were analyzed using SPSS version 17. Sex  comparison was established using student’s t test. Association between diameter and heart weight was established using  Pearson’s correlation test and considered significant at a p-value of ≤0.05. Data were presented using scatter plots. Transverse and supero-inferior diameters of the ostium were 11.04±1.88mm and 9.50±1.80mm respectively. The mean diameter was 10.27 mm. These correlated positively with weight of the heart. When corrected for weight of the hearts, the transverse and supero-inferior diameters were larger in females (0.042 and 0.036 respectively) than in males (0.034 and 0.03 respectively). The diameter of coronary sinus ostium is larger in females and shows positive correlation with weight of the heart. These data should be considered during design and use of cardiac devices introduced through the coronary sinus.Key words: Coronary sinus, ostium, diameter, sex difference

Regional differences in the mural structure of the human coronary sinus

Regional differences in the mural structure of the coronary sinus are important in understanding its physico-mechanical properties and the basis for extent of atrial  fibrillation and ablation. These features are only scarcely reported. This study  therefore aimed at describing regional differences in the mural structure of coronary sinus among black Kenyans. This was a descriptive cross-sectional study on coronary sinuses from fifteen hearts obtained during autopsy on adult black  Kenyans at the Department of Human Anatomy, University of Nairobi.  Five-millimeter-long specimens were taken from the proximal, middle and terminal segments of the coronary sinus and processed routinely for paraffin embedding and sectioning. Seven-micron thick sections were stained with Masson’s Trichrome to demonstrate connective tissue and smooth muscle while Weigert’s Resorcin  Fuschin stain was used to demonstrate elastic fibres. The slides were examined  with a light microscope and photomicrographs taken with a high resolution digital camera. The results are presented in micrographs. The wall comprised three layers namely internal, middle and external. Regional differences were observed in the middle layer. In the proximal segment, there were concentrically oriented smooth muscles scattered within connective tissue. The middle and terminal segments on the other hand comprised cardiac muscle oriented both concentrically and  longitudinally. The muscle was separated by connective tissue rich in elastic fibres and abundant vasa vasora. The external layer comprised connective tissue. In conclusion the middle layer of the wall of the coronary sinus displays regional  differences. The smooth muscle at the proximal segment may confer contractility to enhance blood flow while the cardiac muscle in the other segments enables it to function in synchrony with the right atrium during atrial systole. The complex  arrangement of circular and longitudinal muscle facilitates blood flow and may also constitute a sphincter mechanism.Keywords: Coronary sinus, regional differences, smooth and cardiac muscl

Comparative regional morphometric changes in human uterine artery before and during pregnancy

Introduction Uterine artery undergoes structural modifications at different physiologic states. It is expected that due to its unique course, hemodynamic stresses in the vessel would vary resulting in differences in arterial dimensions. The objective of this study was to investigate regional morphometric changes in the human uterine artery. Methods Twenty four uterine arteries (12 each from non-gravid uteri and gravid uteri) were obtained during autopsy after ethical approval from women aged between 21 to 47 years. Sections from proximal, middle and distal segments of the artery taken within 72 hours were processed for paraffin embedding, sectioned and stained with Mason’s Trichrome. Micrographs of the slides were analyzed using Scion Image Multiscan software. Data were entered into and analyzed with Statistical Programme for Social Sciences. Results The pregnancy related increase in diameter and wall thickness are most pronounced in the proximal segment. In the distal segment, however, wall thickness reduces significantly (p<0.05). Intimal thickness was lesser in pregnancy compared to non-gravid state in all the segments. Conclusion Regional morphometric changes in the uterine artery during pregnancy may be designed to regulate blood flow to the uterus and placenta during pregnancy.Pan African Medical Journal 2012; 13:3

Cardiovascular causes of death in an east African country: An autopsy study

Background: The spectrum of cardiovascular diseases varies between countries. Data from east Africa is scarce, but important in formulating disease management strategies. The aim of this study was to describe the spectrum of cardiovascular causes of death in Kenya. Methods: One hundred and thirty four autopsy cases of cardiovascular related deaths examined at the Department of Human Anatomy, University of Nairobi, from December 2005 to November 2009 were analyzed for disease type, age and gender distribution. Only cases in which cardiovascular disease was the most likely cause of death were included. Data was analyzed using SPSS version 15.0 for Windows and presented using tables and bar graphs. Results: Cardiovascular causes comprised 13.2% of all autopsy cases. Common conditions included myocardial infarction (18.7%), cardiomyopathy (17.2%), subarachnoid hemorrhage (15.7%), pulmonary thromboembolism (14.2%), ruptured aortic aneurysm (11.2%) and hypertensive heart disease (9.0%). Infective pericarditis and rheumatic heart disease comprised 7.5% and 6.7%, respectively. Mean age was 50.4 years, peaking at 40-60 years, with 56.7% aged 50 years and younger. Male: female ratio was 2.7:1. Conclusions: Cardiovascular disease contributes more than 13% of overall mortality in Kenya. Myocardial infarction is the commonest, while rheumatic heart disease is the rarest. It is predominantly male and mainly affects those aged under 50 years. This suggests that non-communicable diseases, while predominant, overlap with infectious conditions as causes of cardiovascular mortality. A search for, and the prevention of, risk factors, combined with prudent management of infection, are recommended. (Cardiol J 2011; 18, 1: 67-72

Tunica Adventitia of the Aorta is an Active Vascular Compartment

The tunica adventitia has previously been regarded as a passive connective tissue covering that offers only nutritive and physical support to the arterial wall. Recently, however, emphasis has been given to its role in atherosclerosis. Although the normal structure may bear the anatomical basis of these functions, microscopic anatomy of the tunica adventitia in normal arteries is seldom reported. These data are important in understanding disease process and potential areas of intervention. The goat is a suitable model for studying cardiovascular disease and the aorta is frequently afflicted by atherosclerosis. This study, therefore, aimed at describing the structure of tunica adventitia of normal aorta in goat. Materials for the study were obtained from abdominal aorta of 6 healthy young adult male goats (capra hircus) age range 12 – 24 months. Fresh specimens from euthanized animals were fixed in 3% phosphate buffered glutaraldehyde, post fixed in 1% phosphate buffered osmium tetroxide then embedded in durcupan. Ultrathin sections were stained with uranyl acetate counterstained with lead citrate and examined with electron microscope. Some specimens were processed routinely for paraffin embedding and sectioning. They were stained with Mason’s Trichrome and Weigert elastic/Van Gieson stains. The tunica adventitia was fibroelastic with numerous capillaries, arterioles and multiple cell types. The cells were active fibroblasts, phagocytic, perivascular and endothelial cells embedded in the fibrous stroma. These findings suggest that the tunica adventitia of the goat aorta is a metabolically active vascular compartment. These features namely microvasculature and multiple cell populations probably enable it to maintain structural and functional integrity and appropriately respond to vascular injury.Keywords: Tunica Adventitia, cells, Capillaries, Arterioles, Atherosclerosi

Involvement of multiple cell lineages in atherogenesis

Atherogenesis is a multicellular event. Early reports concentrated on the role of endotheliocytes, monocyte - macrophages and smooth muscle cells. Recognition of the immuno-inflammatory nature of the process, however, expanded the scope of cellular involvement and more recent reviews emphasize the role of immune and inflammatory cells. In addition, recent studies reveal that other cells are also involved. Elucidation of all the types of cells involved is valuable to inform therapeutic interventions for this disease, but most accounts concentrate on cells which are the target of the study and may fail to include other cells. This review therefore aimed at consolidating information on the various cells involved in atherogenesis. Review of contemporary literature was done for cells in the vessel wall and in blood to check for their potential role in atherogenesis. It has been shown that atherogenesis involves all the cells present in the various coats of the vessel wall – endotheliocytes, smooth muscle cells, fibroblasts, stem cells, pericytes, mast cells, dendritic cells, macrophages and immigrant cells usually found in blood, namely monocytes, neutrophils, lymphocytes, platelets and red blood cells. These cells promote atherogenesis by secreting several products which influence inflammation, migration, proliferation and secretory activity of each other in a manner that synergises their activities. Therapeutic interventions should target the various cell types.Key Words: Cells, arterial wall, blood, atherogenesis

Hibiscus extract mitigates salt induced carotid adventitial changes in rats

The tunica adventitia is an active vascular compartment that actively participates in modulation of vascular structure, function and pathophysiology. Adventitial thickness has recently been accepted as a surrogate marker of atherosclerosis. The effects of salt and chemicals that ameliorate those effects are important in understanding vascular structure, function and pathology. There are few studies on hibiscus and high salt induced vascular pathology. This study, therefore, investigated the effects of hibiscus on salt induced vascular changes on rat carotid artery. The experimental animals were divided into 3 groups of 8 animals each – (i) controls; (ii) high salt diet alone and (iii) high salt + hibiscus extract for a period of eight weeks. At ages 2, 5 and 8weeks 2 – 3 animals were sacrificed for study. They were anaesthetized with ether and perfused with formal saline. Specimens were then obtained from the middle of common carotid artery, fixed in 5% formaldehyde solution, processed routinely for paraffin embedding and 5-micron thick sections stained with Hematoxylin / Eosin and also with Mason’s Trichome/ Aniline blue. Adventitial thickness and volumetric densities of collagen were measured using morphometric techniques. High salt consumption induced statistically significant increase in adventitial thickness from 297.45μm at week 2 to 659.4μm in week 8. In hibiscus fed rats, this increase progressively reduced to 482.55μm in week 8. Volumetric density of collagen was 57% in high salt fed rats but reduced to 45.66% in hibiscus fed rats (p<0.001). The increase in tunica adventitial thickness and collagen density which is induced by high salt can be mitigated by hibiscus extract. This implies that hibiscus has potential to restore salt induced vascular injury. Further studies are recommended to refine the extract.Keywords: adventitial thickness, high salt, hibiscus, collagen, densit

ranching pattern of the left anterior descending coronary artery in a black Kenyan Population

Branching pattern of the left anterior descending coronary artery is important in explaining variations in occurrence of coronary atherosclerosis, informing management strategies for coronary heart disease and interventional cardiology. Data on African populations are, however, scarce. Since coronary heart disease is increasing in Africa, the aim of this study was to describe branching pattern of the left anterior descending coronary artery in an indigenous Kenyan population. Two hundred and eight hearts obtained during autopsy were dissected at the Department of Human Anatomy, University of Nairobi, Kenya. The entire left anterior descending coronary artery was exposed. Number of branches, pattern of termination and level of bifurcation were determined. Images of representative patterns were taken using a high resolution digital camera. Data are presented in macrographs and tables. The number of septal and diagonal branches varied between 1 and 3. Termination occurred in the posterior interventricular sulcus in 68.8% and at the apex in 23% cases. Most common mode of terminal branching was bifurcation (76.9%) followed by trifurcation (11.3%), quadrifurcation (3.4%) and pentafurcation (1.5%). Bifurcation occurred in the distal segment in 48.8% and in the proximal segment in 15% of cases. The left anterior descending coronary artery displays high variability in number of septal and diagonal branches, level of termination, mode of terminal branching and level of terminal bifurcation. These patterns may constitute risk factors for atherosclerosis and should also be acknowledged during cardiac procedures. Pre – operative ultrasound evaluation is recommended to minimize inadvertent iatrogenic injury.Keywords: Left anterior descending, branching, termination, atherosclerosi