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

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

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

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

What is the origin of the labyrinthine artery among black Kenyans?

Origin of labyrinthine artery is important because it influences the presentation of occlusion of anterior inferior cerebellar and basilar arteries. It shows ethnic and geographical variation, but there is no data from black African populations. This study, therefore examined the pattern of origin of labyrinthine artery in adult black Kenyans. Three hundred and fourty six arteries from one hundred and seventy-three formalin fixed brains were examined by dissection at the Department of Human Anatomy University of Nairobi, Kenya. Labyrinthine artery arose from basilar artery in 260 (75.1%); as common trunk with anterior inferior cerebellar artery in 48 (13.9%) and from the latter in 38 (11.0%) of cases. There was no side and gender difference in the pattern of origin. This implies that majority of labyrinthine arteries arise from basilar artery, different from that in oriental, Indo-Asian and Caucasian populations, in which it arises from the anterior inferior cerebellar artery. Preoperative evaluation of basilar artery branching is recommended.Keywords: labyrinthine artery, origin, Kenyan, Basilar, AIC

Anatomical features of renal artery in a black Kenyan population: Correlation with markers of atherosclerosis

Knowledge of anatomical features of the renal artery is important in prediction,  management and control of atherosclerotic renal artery stenosis. These features show population variations but data from black African populations are scarce. The aim of this study was therefore to describe the anatomical features of the renal artery in a black Kenyan population. Six hundred and ten (610) single renal arteries from 305 adult black Kenyans [206 males, 99 females; age range 22 – 79 years] were studied by dissection at Department of Human Anatomy, University of Nairobi, Kenya. Specimens with macroscopic features of stenosis and dilatation were excluded. The implantation angle, length and branching pattern were studied. These features were correlated with intima-media thickness and luminal diameter. The  latter were determined by micrometry on Eosin/hematoxylin stained 5 micron  sections obtained from the proximal segment of the renal artery. Data was analysed by SPSS version 16.0. Student’s t-test, was used to test for statistical significance at 95% confidence interval where P value of < 0.05 was taken as significant. The results are presented in a bar graph, tables and macrographs. The mean  implantation angle was 940±150 (range 580-1250). In 26.7% cases, the angle was more than 1000. Mean length was 34±1.4 mm with 21.6 % of arteries measuring ≤ 20 mm. Variant branching pattern was present in 40.5 % of cases. It comprised trifurcation (33 %), quadrifurcation (6.6 %) and pentafurcation (0.8 %). Higher implantation angle, short arteries and variant branching were associated with  statistically significant higher intima - media thickness and luminal diameter. These results suggest that higher implantation angle, shorter length and variant branching pattern constitute geometric risk factors for renal artery atherosclerosis.  Ultrasound screening for individuals with suboptimal geometric features for renal artery atherosclerosis is recommended.Keywords: anatomical risk factors, atherosclerosis, renal arter

Pattern of femoro-popliteal aneurysms in an African population Padrão de aneurismas femoro-poplíteos em uma população africana

Objective: To describe the pattern of femoro-popliteal aneurysms in an African Kenyan population. Patients and methods: Records of African in-patients with diagnosis of femoral or popliteal aneurysms admitted at the Kenyatta National Hospital, Nairobi, Kenya, from January 1998 to December 2007 were examined for presentation, diagnosis, risk/comorbid factors, site, age, and gender distribution. Data were analyzed using SPSS 13.0 and presented using tables. Results: Femoro-popliteal aneurysms constitute 33 out of 96 of peripheral cases (34.4%). The most common presentations were pulsatile mass (48.5%) and pain and swelling (33.3%). Pain alone and bleeding occurred in 9.1% each. Diagnosis was performed through Doppler ultrasound (45.5%), angiography (30.3%) and ultrasonography (24.3%). Aneurysms were associated with trauma (51.5%), atherosclerosis (21.2%), smoking (9.1%) and hypertension (6.1%). Site distribution was common femoral (33.3%), superficial femoral (36.4%) and popliteal (30.3%). Mean age was 46 years (range 13-79 years); with 20 (60.6%) of them occurring in individuals aged 50 years and younger. Male:female ratio was 15:1. Conclusion: In the present study, femoro-popliteal aneurysms constituted less than 40% of peripheral aneurysms, and superficial femoral artery was the most common site. They occurred predominantly in males aged 50 years and younger and were associated mainly with trauma and atherosclerosis. Prevalence, site and age distribution of these aneurysms in the Kenyan population differs from that described in studies of Caucasian populations.Objetivo: Descrever o padrão de aneurismas femoro-poplíteos em uma população africana do Quênia. Pacientes e Métodos: Prontuários de pacientes africanos internados com o diagnóstico de aneurisma femoro-poplíteo no Hospital Kenyatta, Nairóbi, Quênia, de janeiro de 1998 a dezembro de 2007 foram examinados quanto a apresentação, diagnóstico, fatores de risco/comorbidades, local, idade e gênero. Os dados foram analisados usando o Program SPSS 11.50 e apresentados em tabelas. Resultados: Aneurismas femoro-poplíteos constituem 33 dos 96 casos de aneurisma periférico (34,4%). As apresentações mais comuns foram massa pulsátil (48,5%) e dor e inchaço (33,3%). Dor isolada e sangramento ocorreram em 9,1% cada. O diagnóstico foi feito por ultrassonografia Doppler (45,5%), angiografia (30,3%) e ultrassonografia simples (24,5%). Aneurismas foram associados a trauma (51,5%), aterosclerose (21,2%), tabagismo (9,1%) e hipertensão arterial (6,1%). A distribuição por locais foi femoral comum (33,3%), femoral superficial (36,4%) e poplítea (30,3%). A média de idade foi de 46 anos (variando de 13 a 79 anos), com 20 casos (60,6%) ocorrendo em indivíduos com 50 anos de idade ou menos. A relação masculino:feminino foi de 15:1. Conclusão: No presente estudo, aneurismas femoro-poplíteos constituíram menos de 40% dos aneurismas periféricos, e a artéria femoral superficial foi o local mais comum. Eles ocorreram predominantemente em homens com idade igual ou menor que 50 anos e foram associados principalmente a trauma e aterosclerose. A prevalência, local e distribuição destes aneurismas diferem das descritas nas populações brancas