Impact of prehypertension on left ventricular mass and QT dispersion in adult black Nigerians

The heterogeneity of individuals with blood pressure (BP) < 140/90 mmHg in terms of cardiovascular (CV) risk was reported as early as 1939 by Robinson and Brucer.1 BP in the range of 120–139/80–89 mmHg (labelled then as prehypertension) was observed to be associated with high risk of progression to hypertension (HT) and cardiovascular disease (CVD) later in life when compared with BP < 120/80 mm Hg.1The term prehypertension was adopted in May 2003 by the Seventh Report of the Joint National Committee on Prevention, Detection, Evaluation and Treatment of High blood Pressure (JNC-7) to describe BP range of 120–139/80–89 mmHg.2 The resuscitation of this terminology/concept in JNC-7 was a sequel to the documentation of a higher morbidity in individuals with prehypertension in landmark publications.3-5 Prehypertension (PHT) was defined in JNC-7 not only to emphasise the excess risk associated with BP in this range, but also to focus increased clinical and public health attention on prevention.2,6,7Prevalence rates of PHT among adults in the United States, Ghana and northern Nigeria have been reported to be 31, 40 and 58.7%, respectively.7-9 In most studies, including the ones above, PHT was more prevalent than hypertension.7-9 Though PHT is associated with increased risk of major CV events independently of other CV risk factors,10 most individuals (90%) with PHT have at least one cardiovascular risk factor such as dyslipidaemia, abdominal obesity, hyperinsulinaemia, impaired fasting glucose levels, insulin resistance, a prothrombotic state, tobacco use, endothelial dysfunction, and impaired vascular distensibility.6,7,9,10QT interval dispersion (QTd) (the difference between the longest and the shortest QT intervals on a surface ECG), when excessive, is associated with increased risk of cardiovascular morbidity and mortality in population studies, and many clinical conditions, including hypertension.11,12 This has been related to ventricular electrical instability, providing the necessary substrate for lethal ventricular arrhythmias.12,13 Greater QTd and left ventricular mass have been demonstrated in hypertensive individuals compared with normal individuals.11,13,14Considering the well-established, linear relationship between BP and the risk of cardiovascular events, the CV risk associated with PHT is intermediate between normotension and hypertension.2,03 Hence, electrocardiographic and echocardiographic indices of target-organ damage in PHT may also be intermediate between normotension and hypertension. The aims of this study were: (1) to compare the QTd and indices of left ventricular hypertrophy in adult black normal and prehypertensive subjects, and (2) to evaluate the relationship of QTd with electrocardiographic and echocardiographic indices in these subjects.     

Carbon monoxide poisoning increases Tpeak–Tend dispersion and QTc dispersion

Carbon monoxide (CO) poisoning may cause myocardial toxicity and life-threating cardiac arrhythmias.1-3 Acute coronary syndrome, myocardial injury, myocardial dysfunction, cardiac arrest and various types of arrhythmias have been reported in patients with acute CO poisoning.4 CO binds myocardial myoglobin and reduces myocardial oxygen reserve.5 Previous studies reported that episodes of atrial fibrillation, premature ventricular beats and sinusal tachycardia may be seen in patients with acute CO poisoning.6,7 Recent studies also suggested that risk of atrial and ventricular arrhythmia is increased in CO poisoning, due to prolonged QT_c and QT_c dispersion.2,3,8Ventricular repolarisation can be evaluated by measuring QT interval, corrected QT interval, and QT dispersion. Among these parameters, QT dispersion represents the heterogeneity of ventricular repolarisation and was clearly shown to be associated with ventricular arrhythmia.9 T_peak–T_end (T_pT_e) interval is defined as the interval between the peak point and endpoint of the T wave on surface electrocardiography and is a novel index of transmural dispersion of ventricular repolarisation.10 T_pT_e/QT ratio and T_pT_e/QT_c ratio were used in previous studies as an electrocardiographic index in the evaluation of risk of ventricular arrhythmia.11,12The effect of acute CO poisoning on QT intervals was investigated in a number of studies.2,3,8 However, to the best of our knowledge, T_pT_e interval, T_pT_e dispersion, T_pT_e/QT ratio and T_pT_e/QT_c ratio have not been investigated sufficiently in patients with CO poisoning. In this study, we aimed to investigate the effect of acute CO poisoning on electrocardiographic parameters, which indirectly show ventricular repolarisation heterogeneity. We also investigated the relationship between carboxyhaemoglobin (COHb) levels and these parameters.     

Evaluation of left atrial mechanical function and atrial conduction abnormalities in Maras powder (smokeless tobacco) users and smokers

Tobacco use can be classified into smoking and smokeless tobacco. Smokeless tobacco is chewed or is absorbed by the nasal and oral mucosae. A type of smokeless tobacco called Maras powder (MP) is used mostly in the south-eastern region of Turkey, and in many cases users become addicted. It is obtained from a tobacco plant species known as Nicotiana rustica Linn. Nicotine concentrations in the tobacco used to produce MP are eight to 10 times higher than those in tobacco used to produce cigarettes.1 MP and its negative effects on the cardiovascular system have been well studied. MP is consumed in such a way that increase in oxidative stress is inevitable and as a result it accelerates the atherosclerotic process.2,3Cigarette smoke includes nicotine and toxic substances such as carbon monoxide and polycyclic aromatic hydrocarbons.4 Inhalation of these substances predisposes to several different atherosclerotic syndromes,5,6 and is also associated with the occurrence of cardiac arrhythmia.7,8The pathophysiological mechanism of cigarette smoking-induced cardiac arrhythmia is complicated, and the pro-fibrotic effect of nicotine on myocardial tissue with its consequent increased susceptibility to catecholamines, may play a role. Moreover, other components of cigarette smoking, such as carbon monoxide, as well as oxidative stress, are likely to cause the generation of arrhythmias. It is also known that cigarette smoking leads to cardiac autonomic dysfunction,9 and it has been implicated in prolonged QT intervals in healthy individuals.10 However, the nicotine concentration in the blood is more likely to cause the pro-arrhythmic effect of cigarette smoking.7,11 The risk of atrial and ventricular arrhythmia rises due to increased nicotine levels.9-12The prolongation of intra- and inter-atrial electromechanical intervals and the inhomogeneous propagation of sinus impulses are well-known electrophysiological characteristics of atria that are prone to fibrillation.13 Left atrial (LA) volume and LA mechanical function have recently been identified as a potential indicator of cardiac disease and arrhythmias.14,15 Prolongation of atrial electromechanical interval and impaired LA mechanical function are associated with adverse clinical events, including atrial fibrillation, stroke, diastolic dysfunction and left ventricular failure.16,17LA mechanical function and atrial conduction abnormalities have not been investigated in MP users and smokers. Therefore, our study was planned to evaluate whether MP damages intra- and inter-atrial conduction intervals and LA mechanical function as much as cigarette smoking.     

The proposed role of plasma NT pro-brain natriuretic peptide in assessing cardiac remodelling in hypertensive African subjects

Left ventricular hypertrophy (LVH) represents an important index of pre-clinical disease, and carries incremental prognostic value beyond that afforded by traditional coronary risk factors.1 In a large cohort of black persons, LVH proved to be an even more powerful predictor of mortality than coronary artery disease and left ventricular ejection fraction (LVEF).2 Hence early detection of LVH is very important in the management of the hypertensive patient.Electrocardiography can be very useful in assessing LVH, especially in middle- and low-income countries, because it is relatively cheap, accessible and not much expertise is required to operate an electrocardiography machine. Electrocardiographic criteria for LVH are, however, not very sensitive, while the alternative more accurate method of echocardiography is uneconomical, especially in resource-limited countries.3 Besides requiring more expertise, the results may not be adequate in all patients, especially in those with obesity or pulmonary disease.4 This situation has led to research on the use of biomarkers such as NT-proBNP and BNP in the detection of the presence of LVH and monitoring its regression.5B-type natriuretic peptide is a cardiac neurohormone secreted by myocardial cells located on both the atria and ventricles, mainly by LV myocardial cells in response to volume expansion and pressure overload.6,7 Plasma BNP and NT-proBNP levels are a useful marker of LVH in hypertension, and have also been found to rise progressively with increasing severity of hypertension, particularly when ventricular hypertrophy is present.6 Similarly, plasma BNP and NT-proBNP levels are useful to discriminate between patients with regard to cardiac remodelling and could be considered as a screening tool to select hypertensive patients eligible for transthoracic echocardiography.5 NT-proBNP is also a useful biomarker in differentiating hypertensive subjects with LVH from those with heart failure.8,9Most of the current knowledge and published data on the use of plasma NT-proBNP in hypertensive LVH and hypertensive heart failure (HHF) are based on studies in Europe and the United States of America, with a dearth of data in black Africans in whom the burden of hypertension and hypertensive heart disease is very high.10,11 For example, the THESUS study, which studied 1 006 acute heart-failure subjects in nine sub-Saharan African countries, inclusive of Nigeria, showed that hypertension was the commonest cause of heart failure, accounting for heart failure in 45.4% of cases.12 In addition, most previous studies on this subject never considered LV diastolic function or RV function, both of which are reported to be prognostic markers in hypertensive heart failure.13,14 We therefore decided to examine the relationship between circulating NT-proBNP and left and right ventricular remodelling in a black African hypertensive cohort.     

Hypertensive retinopathy and its association with cardiovascular,renal and cerebrovascular morbidity in Congolese patients

Hypertension is a major public health problem worldwide and on the African continent.1,2 The disease, once considered to be rare outside Europe and North America, is now a leading cause of disability and mortality in developing countries. Its prevalence is projected to reach 30% worldwide by 2025.2Poor control of hypertension increases the likelihood of complications affecting the cardiovascular and cerebrovascular systems, kidney and retina, often labelled under the term target-organ damage (TOD).1 The development of subclinical TOD, such as left ventricular hypertrophy (LVH), increased intima–media thickness of the large vessels, microalbuminuria following glomerular dysfunction, cognitive decline and hypertensive retinopathy precedes the occurrence of major complications, which include stroke, congestive heart failure and myocardial infarction, renal failure and retinal vascular occlusions.3-5 In the Democratic Republic of Congo (DRC), the prevalence of systemic hypertension has been reported to be over 25%,6,7 whereas hypertension and associated complications account for over 20% of deaths among adults.8Studies have demonstrated that TOD increases cardiovascular risks over that already associated with elevated blood pressure alone. For example, it has been shown that once LVH has developed following long-standing systemic hypertension, it behaves as an independent risk factor and a predictor of both further cardiac complications,9 and other incident vascular events such as ischemic stroke and myocardial infarction.10 Similarly, the presence of cerebrovascular and renal damage may raise cardiovascular risk over that conferred by hypertension itself.11,12In addition, hypertensive retinopathy has long been known as a predictor of systemic morbidity and mortality. Both epidemiological and clinical studies have provided evidence that markers of hypertensive retinopathy are associated with raised blood pressure, systemic vascular diseases, and subclinical cerebrovascular and cardiovascular disease, and predict incident clinical stroke, congestive heart failure and mortality due to cardiovascular complications.13 This association of hypertensive retinopathy with other TOD has also been shown to be independent of blood pressure and other risk factors, which supports the recommendation that retinal vascular changes should be assessed in individuals with systemic hypertension for better extra-ocular TOD risk stratification.13While the number of reports on hypertensive TOD has been on the rise on the African continent, the relationship between hypertensive retinopathy and other TOD has largely remained unexplored. The aim of this study was to examine the association of hypertensive retinopathy with LVH, chronic kidney disease (CKD) and stroke in Congolese patients.     

Prevalence of anaemia among patients with heart failure at the Brazzaville University Hospital

Heart failure (HF) is a frequent cause of hospitalisation in cardiology. Its prognosis depends on several factors, including anaemia, which is common among patients with heart failure.1 Anaemia is an independent prognostic factor for mortality in chronic HF and is associated with higher rates of mortality, hospitalisation and re-admission.2,3 Anaemia is a powerful independent predictor of death and hospitalisation in systolic and diastolic dysfunction.2,4-7In order to improve the management of patients suffering from systolic and diastolic HF, it is critical to understand the relationship between HF and anaemia, and the possible outcomes. The aim of this study was to determine the prevalence of anaemia in patients with heart failure and to evaluate its impact on the prognosis of patients in Brazzaville, Congo.     

Short-term outcomes after hospital discharge in patients admitted with heart failure in Abeokuta,Nigeria: Data from the Abeokuta Heart Failure Registry

Heart failure (HF) has emerged as a global epidemic in at-risk populations, including those living in high-income countries and, as recently described, in low- to middle-income regions of the world, such as sub-Saharan Africa.11-4 While there are well-established HF registries to capture both the characteristics and health outcomes among those hospitalised with AHF in Europe,5,6 North America,7,8 and the Asia–Pacific region,3,9,10 there are few reports from sub-Saharan Africa.11 This includes Nigeria (the most populous country in the region), where HF has emerged as a potentially large public health problem.1Although there have been many therapeutic gains in the management of chronic HF,12 leading to improved overall survival rates,13 there has been very little parallel success (pending further evaluation of the recently reported RELAX trial14 with regard to AHF). This is particularly important when one considers the high proportion of patients who still require hospitalisation for acute HF, and associated high levels of in-patient case fatality and poor short- to medium-term health outcomes.Given the paucity of data describing health outcomes in unselected patients hospitalised with AHF in Nigeria (and indeed the wider sub-Saharan Africa), we examined short- (30 days) to medium-term outcomes (180 days) in consecutive subjects with AHF recruited into the Abeokuta HF registry over a period of six months. Standardised data collected via the registry were used to both describe the baseline characteristics of the cohort and identify correlates of mortality during the six-month follow up.     

Sickle cell trait is not associated with chronic kidney disease in adult Congolese patients: a clinic-based,cross-sectional study

Chronic kidney disease (CKD) and end-stage renal disease (ESRD) are associated with significant cardiovascular (CV) and renal morbidity and mortality rates, with substantial economic burden.1,2 Therefore, early identification of CKD patients at high risk of progression is urgently needed for early and targeted treatment to improve patient care.1-3 Diabetes and hypertension are the primary risk factors for CKD and ESRD but do not fully account for CKD and ESRD risk.1-3 Marked variability in the incidence of CKD suggests that factors other than diabetes and hypertension contribute to its aetiology.4Family studies have suggested a genetic component to the aetiology of CKD and ESRD.5 In African Americans, high-risk common variants in the Apol1/MYH9 locus may explain up to 70% of the differences in ESRD rates between European and African Americans.5 While this finding has great implications for ESRD, the identification of additional risk factors for CKD, including genetic loci in association with estimated glomerular filtration rate (eGFR), may help to advance our understanding of the underpinnings of CKD in African Americans.5 In this era of identifying genetic risk factors for kidney disease, it may be appropriate to revisit one of the most common genetic disorders: sickle cell haemoglobinopathies.5In this regard, sickle cell trait (SCT), present in approximately 7–9% of African Americans, has been reported to be a potential candidate gene.6 However, conflicting reports exist as to whether SCT is a risk factor for the progression of nephropathy.6,7 Haemoglobin S (HbS) was selected for in Africa because of the protection it affords from malarial infection, a scenario similar to the protection from trypanosomal infection provided by heterozygosity for APOL1 nephropathy risk variants.6Whereas APOL1 contributes to risk for nephropathy in an autosomal recessive inheritance pattern, HbS reportedly had a dominant effect on risk, with SCT being associated with ESRD.6 In line with this finding, a few small studies on African Americans reported HbS as an independent risk factor for CKD and ESRD.8 However, other studies using a large sample of African Americans stated that SCT was not independently associated with susceptibility to ESRD in African Americans,6 highlighting the need for further studies in other populations such as those of sub-Saharan Africa where SCT is prevalent.Although SCT is very prevalent in black Africans,9 few studies have been conducted to assess the association between SCT and CKD.10 In Democratic Republic of Congo (DRC), the prevalence of CKD and SCT has been reported to be 12% and 17–24%, respectively.11-13 No study has evaluated the frequency of SCT among CKD patients to assess its association with reduced kidney function. Therefore, the aim of this clinic-based, cross-sectional study was to assess the potential association between SCT and CKD among adult Congolese patients.     

Ambulatory blood pressure profiles in a subset of HIV-positive patients pre and post antiretroviral therapy

South Africa has 5.6 million people living with HIV/AIDS and has the largest antiretroviral therapy (ART) programme globally, with more than two million people accessing ART.1 Although ART has significantly decreased the mortality rate from HIV infection, these individuals are now living longer and are at risk of developing metabolic (dyslipidaemia, lipodystrophy, dysglycaemia), cardiovascular and renal complications from ART and chronic exposure to HIV infection.2-7Chronic HIV and ART are associated with increased risk of developing hypertension.8 In studies of HIV-positive patients in high-income countries, hypertension prevalence ranges from 13 to 34%.9,10 However, data from low- and middle-income countries remain sparse.Nocturnal blood pressure (BP) is superior to daytime or office BP as a predictor of cardiovascular disease.11 Non-dipping is defined as an abnormal diurnal rhythm manifested by a blunted nocturnal decline in systolic BP (SBP).11 It is associated with more severe hypertensive target-organ damage (left ventricular hypertrophy, microalbuminuria and cerebrovascular disease) and is also a predictor of increased cardiovascular risk, both in hypertensive and normotensive populations.11Studies from high-income countries have shown an increased prevalence of non-dipping with HIV infection.9,12 However, the participants in these studies were largely white, middle-aged males. Since the majority of subjects with HIV infection in sub-Saharan Africa are young black females, it is not known whether the same relationship between dipping status and HIV infection would be found. In addition, there are data showing that black HIV-negative individuals have less nocturnal dipping compared to their white counterparts.5,13,14Therefore, the aims of this study were to document the prevalence of chronic kidney disease (CKD) and hypertension at baseline (ART naïve) in a healthy HIV-positive cohort, and to assess changes in these parameters after six months on ART. The characteristics of ambulatory blood pressure (ABP) in a subset of patients were to be recorded and compared to a control group of HIV-negative patients.     

Prevalence of the metabolic syndrome and determination of optimal cut-off values of waist circumference in university employees from Angola

The metabolic syndrome is characterised by the presence of multiple metabolic risk factors for cardiovascular (CV) disease1 and type 2 diabetes mellitus.2 In clinical practice, the metabolic syndrome is diagnosed by combinations of three or more of the following five risk factors: central obesity, elevated blood pressure, glucose intolerance, hypertriglyceridaemia and low high-density lipoprotein cholesterol (HDL-C).3-6Worldwide the prevalence of the metabolic syndrome is increasing and becoming a pandemic, and this increase has been mainly attributed to sedentary lifestyle and obesity.7 However, levels of prevalence may vary greatly according to cut-off points of diagnostic criteria and the ethnic group studied.8In sub-Saharan Africa, the majority of countries are experiencing a rapid demographic and epidemiological transition.9,10 Available information from studies in African populations reported a prevalence of the metabolic syndrome ranging from 0% to as high as about 50% or more, depending on the population setting.11 These data however, are limited to some countries,12-21 since there are no available data for the majority of African countries.Angola is a country in sub-Saharan Africa, which in the last few years has undergone significant political changes, accompanied by a rapid economic growth and increased urbanisation. These changes may imply an increasing prevalence of factors contributing to the metabolic syndrome, such as obesity, insufficient physical activity, dyslipidaemia, high blood pressure and glucose intolerance. However, the prevalence of the metabolic syndrome and which factors contribution more to its occurrence in the Angolan population remain unknown.Despite the efforts of several organisations to regulate the algorithm for a definition of the metabolic syndrome,3-5 there is inconsistency on cut-off levels of waist circumference (WC) for defining the metabolic syndrome in several populations. The International Diabetes Federation (IDF)5 recommended the use of ethnic or country-specific cut-off values of WC for the majority of populations, a recommendation reinforced in the Joint Interim Statement (JIS),7 which tried to define different criteria for a definition of the metabolic syndrome.These cut-off values were defined using different methods. For example, Western countries derived their cut-off values of WC from a correlation with body mass index (BMI),4,22 whereas Asian groups tried to define WC cut-off values yielded by receiver operating characteristics (ROC) curve analyses.23 Due to a lack of specific data from African populations, cut-off points of WC derived from the European population have been recommended,5,7 although emerging data suggest that African-specific cut-off values would be different from the European cut-off points currently recommended by the IDF.18,24,25 Therefore, definition of a more reliable cut-off point for WC is needed to build a consistent tool for diagnosis of the metabolic syndrome in sub-Saharan African populations.The aim of this study was to determine the prevalence of the metabolic syndrome in a sample of Africans from Angola, using either the third report of the National Cholesterol Education Program Adult Treatment Panel (ATP III)4 or the JIS7 criteria. Additionally, this study tried to identify threshold WC levels that best predict other components of the metabolic syndrome.     

Endothelial nitric oxide synthase levels and their response to exercise in patients with slow coronary flow

Slow coronary flow (SCF), described for the first time by Tambe and his colleagues in 1972, is an angiographic diagnosis characterised by a low rate of flow of contrast agent in the epicardial coronary arteries, together with typical angina pectoris and normal coronary arteries.1 Even though micro- and macrovascular disease findings have been identified, such as myofibrillar hypertrophy, myofibrillar degeneration, hyperplastic fibromuscular thickening, luminal narrowing, endothelial degeneration, endothelial dysfunction and diffuse atherosclerosis, which may lead to reduced coronary flow reserve, uncertainties still exist in the aetiopathogenesis.2,3Coronary blood flow and oxygen transport to the myocardium are increased by autoregulatory mechanisms for the increased metabolic needs associated with effort. The amount of oxygen extracted from the blood also increases, which leads to a decrease in the concentration of oxygen in the blood. Mitochondrial metabolism is altered by coronary endothelium-derived nitric oxide (NO) in an attempt to reduce the growing energy requirements.4,5Vascular endothelium exhibits a number of haemostatic functions in normal blood vessels. NO is a key molecule for normal autoregulatory mechanisms, such as modulating the vasodilator response to tachycardia and exercise,6 and it has also been found to be essential for flow-mediated dilatation of large human arteries in vivo.7 Endothelial nitric oxide synthase (eNOS) is an enzyme involved in the synthesis of NO.8 Decreased plasma eNOS level is an important indicator of endothelial dysfunction.9To our knowledge, there has been no study evaluating plasma eNOS levels and their response to exercise in SCF patients. Therefore we aimed to investigate the plasma levels of eNOS before and after exercise in patients with SCF.     

Effects of rosuvastatin on ADMA,rhokinase, NADPH oxidase,caveolin-1, hsp 90 and NFkB levels in a rat model of myocardial ischaemia–reperfusion

Ischaemic heart disease remains among the major causes of morbidity and mortality worldwide. The most common form is reduction in blood flow in the coronary arteries supplying blood to the myocardium due to atherosclerotic plaques or vasospasm.1 After ischaemia, reperfusion of the tissue is of great importance for maintenance of the viability of the ischaemic tissue. However reperfusion may paradoxically lead to some morphological changes, enzyme destruction and even death of the still-viable tissue that may be rescued.2Ischaemia–reperfusion (I/R) injury is the mainstay of myocardial infarction, cerebral ischaemia, stroke, haemorrhagic shock and surgical interventions such as organ transplantation, cardiac surgery, coronary angioplasty and thrombolytic treatment-related pathophysiology.3 Endothelial dysfunction, oxidative stress and inflammation are among the most common mechanisms of I/R injury.4,5Asymmetrical dimethyl arginine (ADMA) is an endogenous nitric oxide synthase (eNOS) inhibitor. Its importance is becoming more recognised and further studies are required to determine its use in clinical diagnosis. Available evidence indicates that oxidative stress leads to changes in the activity of enzymes involved in the production and degradation of ADMA.4,5 High levels of ADMA and low levels of nitric oxide (NO) in the coronary arteries of patients with vasospastic angina have been reported.6In the cardiovascular system, NADPH oxidase accounts for the production of reactive oxygen species (ROS), which is produced not only during I/R injury but also under physiological conditions.7 The pro-oxidative NADPH oxidase is present in the plasma membranes of neutrophils, which are an important source of free radical formation and I/R injury.8 Additionally, the rhokinase pathway, which has an important role in regulation of vascular smooth muscle tone, has been shown to be involved in I/R injury, thus making its inhibition a potential target for limiting I/R injury.9It has been reported that inflammatory NFkB expression increased in the I/R-related infarct area; inflammation was suppressed when NFkB expression was inhibited, and cardiac preservation was provided.10 In this context, caveolin-1 was shown to regulate eNOS activation consistently with other signalling molecules such as hsp 90.11 Interaction of hsp 90 with eNOS increases eNOS activity, and consequently, NO production increases.12,13 Myocardial caveolin-1 content is reported to decrease following ischaemia–reperfusion.14 Caveolin-1 deficiency was noted to aggravate cardiac dysfunction and reduce the survival rate in mice that had experienced myocardial infarction (MI).15Rosuvastatin is a synthetic hydrophilic statin widely used in the treatment of dyslipidaemia, as it increases levels of highdensity lipoprotein (HDL) cholesterol, and reduces low-density lipoprotein (LDL) cholesterol and triglyceride levels. Statins have been reported to have anti-inflammatory, antiproliferative, antithrombotic, anti-atherogenic and antihypertensive effects in addition to their cholesterol-lowering effects.8,16-18 Recent studies indicate that rosuvastatin decreases levels of ADMA in hypercholesterolaemia,19 levels of caveolin,20 and also NFkB levels21 in subaracnoid bleeding.To our knowledge, the effects of rosuvastatin on ADMA, rhokinase, caveolin-1, hsp 90 and NFkB levels are not known in cardiac I/R injury. In this study, we aimed to investigate the influence of rosuvastatin on oxidative stress-related rhokinase, NADPH oxidase, ADMA, caveolin-1 and hsp 90 levels in a rat model of I/R injury.     

Postoperative atrial fibrillation in patients with left atrial myxoma

Paroxysmal atrial fibrillation (AF) is the most common arrhythmia following cardiac surgery such as coronary artery bypass grafting (CABG), and often occurs between the second and fourth postoperative days.1,2 The reported incidence of paroxysmal AF after CABG surgery varies widely, from five to 40%, which is lower than in cases of valvular cardiac surgery.3,4 Although this arrhythmia is usually benign and self-limiting, it may also be associated with increased risk of embolic events, haemodynamic instability, haemorrhagic complications, prolonged hospital stay and higher rates of re-admissions, increasing the healthcare costs.5-7Several risk factors have been proposed for paroxysmal AF after CABG or valvular cardiac surgery, such as advanced age, genetic predisposition, chronic obstructive pulmonary disease, heart failure or increased peri-operative ischaemia.8-10 In addition, certain echocardiographic parameters such as left atrial (LA) diameter or left ventricular (LV) function, and electrocardiographic parameters including P-wave duration and P-wave dispersion (Pd) have been shown to be associated with postoperative AF.11-13Although postoperative AF and its predictors after CABG and valvular surgery have been well researched, no study has been performed to explore the incidence or predictors of postoperative AF in patients with LA myxoma. The aim of this study was to identify the prevalence and predictors of postoperative AF in a pure cohort of patients with LA myxoma.     

Epidemiological African day for evaluation of patients at risk of venous thrombosis in acute hospital care settings

Acute venous thromboembolism (VTE) is a complication in patients hospitalised for a wide variety of acute medical and surgical conditions.1,2 In developed countries, VTE is the most common preventable cause of death among hospitalised patients. Over the last 30 years, extensive research has demonstrated a high risk of VTE in patients who undergo major surgery or experience severe trauma. Patients hospitalised for acute medical illness have approximately the same level of VTE risk as patients who undergo major general surgery.3-5The benefits of VTE prophylaxis are similar for both medical and moderate-risk surgical patients.6,7 VTE prophylaxis is substantially underused. There is great variation in the use of prophylaxis between countries. Even when prophylaxis is used, it may be used sub-optimally.8-10 Although some surveys and studies suggest that physicians have begun to recognise VTE as a serious health problem and use prophylaxis for at least some high-risk patients, a number of recent studies demonstrate that VTE prophylaxis remains underutilised.11-20     

Vascular calcification is not associated with increased ambulatory central aortic systolic pressure in prevalent dialysis patients

Vascular calcification (VC) is a novel vascular risk factor strongly associated with mortality in dialysis patients.1,2 Although various explanations exist for this association, one mechanism is through alterations in pulse-wave velocity (PWV). Vascular calcification is associated with increased aortic PWV,3 which in turn is associated with raised central aortic systolic pressure (CASP) and reduced coronary perfusion.4,5 As a result, brachial pressure may significantly under- or over-estimate central pressure.6Not surprisingly therefore, central blood pressure parameters have been shown to predict hard cardiovascular endpoints (including mortality) better than concomitant brachial measurements.7-10 Whether vascular calcification is directly linked to central pressures is, however, unknown since there are many determinants of aortic stiffening other than calcification. Furthermore, a primarily damaged and stiff aorta may be the target for secondary deposition of calcium.11CASP can be calculated using applanation tonometry-derived peripheral pulse waveforms and associated software.12 This avoids the obvious disadvantages of invasive central pressure determination. The major disadvantage of standard techniques, however, is the one-dimensional static measurement that is obtained, with no information on ambulatory values or nocturnal dipping status.Loss of normal nocturnal systolic blood pressure dipping is prevalent in chronic kidney disease (CKD) and likely contributes to cardiovascular disease.13 Dipping, which can only be assessed using ambulatory monitoring techniques, correlates better with left ventricular mass index (LVMI) in end-stage renal disease than office-based blood pressure measurement.14,15There have been calls for the routine use of ambulatory blood pressure monitoring (ABPM) in clinical studies of CKD13,16 and indeed, for investigations into the utility of ambulatory CASP in clinical practice.17,18 Combining both ambulatory and central pressure measurements is an attractive strategy, but until recently has not been technically possible.A non-invasive wrist watch-like device, BPro with A-Pulse CASP software (HealthStats, Singapore) was recently approved by the US Food and Drug Administration (FDA: K072593) for the measurement of CASP as well as ambulatory blood pressure. It is a small, wrist watch-like, cuffless monitor which obtains radial pressure waveforms by applanation tonometry. BPro has the ability to measure ambulatory CASP and although not yet commercially available, the manufacturer is able to convert data into ambulatory CASP using the same software.As part of a recently published study on vascular calcification,19 we sought to prospectively evaluate whether the presence of vascular calcification had any relationship with ambulatory CASP in our young CKD-5D cohort using the BPro® radial pulse-wave acquisition device. We also sought to determine the utility of inter-dialytic office brachial and central blood pressure measurements in predicting ambulatory parameters.     

Analysis of clinical outcomes of intra-aortic balloon pump during coronary artery bypass surgery

An intra-aortic balloon pump (IABP) increases coronary blood flow and reduces left ventricular afterload.1-3 It helps to increase the necessary amount of time for heart recovery in low cardiac output syndrome following a cardiopulmonary bypass (CPB) or ischaemic events. In earlier reports, researchers had suggested that postoperative heart failure was the single indication for IABP support.1,2 However, these indications have widened, and the use of IABP support has recently become more common.Frequently reported complications of IABP include bleeding, aorto-iliac injury and thrombocytopenia.4,5 In-hospital mortality and early mortality of patients requiring IABP support is high, ranging from 26 to 50%, due to the cardiac problems that initially led to the need for this support.6,7The elderly population is continuously increasing across the globe. Parallel with this increase, the number of older patients being referred for coronary artery bypass grafting (CABG) has also increased.8 Although several studies have shown a significant increase in surgical mortality of elderly patients,9 there have been no studies regarding clinical outcomes of IABP in elderly patients.In the present study, we aimed to analyse and compare older with younger patients, regarding clinical features, postoperative complications, intensive care unit and hospital stays, and morbidity and mortality rates in patients who had undergone CABG surgery and required IABP support.     

Simultaneous coronary artery bypass grafting and carotid endarterectomy can be performed with low mortality rates

There is controversy over the best approach for patients with concomitant carotid and coronary artery disease.1 Therapeutic strategies include isolated coronary artery bypass grafting (CABG), staged carotid endarterectomy (CEA) and CABG, reversed staged CEA and CABG, and simultaneous procedures under single anaesthesia.2Although reported experiences over three decades are available, combining CEA with CABG remains to be elucidated.3 Furthermore, risk of cerebrovascular accident (CVA), which is one of the major predictors of prognosis of CABG, has been reported to increase up to 14% in patients with severe carotid artery stenosis (> 80%).4-9Peri-operative neurological events such as stroke after CABG are the major neurological complications, which increase with age.10 The incidence of peri-operative stroke has been well documented at approximately 2% of all cardiac surgeries.11 Despite reduced overall complication rates over the years after CABG, the incidence of stroke remains relatively unchanged.10The aetiology of peri-operative stroke is multi-factorial including hypotension or hypoperfusion-induced reduced brain flow, atherosclerosis due to micro- or macro-embolisation, and intra- or extra-cranial vascular diseases.5 In addition, carotid artery disease is a critical factor; however, it is considered unlikely to be the only culprit for peri-operative strokes.12Although no consensus on the optimal management of patients with concomitant carotid and coronary artery disease has been reached,13 simultaneous CEA and CABG surgery is often associated with low rates of mortality and morbidity.14-17 In this study, we report our experience with simultaneous CEA and CABG surgery in our clinic in the light of data in the literature.     

Prevalence and risk factors for hypertension and association with ethnicity in Nigeria: results from a national survey

Hypertension is increasingly being recognised as an important public health problem in sub-Saharan Africa, with 26.9% of men and 28.4% of women in 2000 being estimated to have hypertension.1 Although lower than the prevalence in high-income countries (37.4% in men and 37.2% in women), in terms of numbers of people affected, the burden of hypertension in low- and middle-income countries is greater due to the large population.1Hypertension has been recognised as a strong independent risk factor for heart disease and stroke and a predictor of premature death and disability from cardiovascular complications.2 It has been reported that 13.5% of deaths and 6% of disability-adjusted life years (DALYs) were attributed to hypertension globally, and for low- and middle income people, these figures were 12.9 and 5.6%, respectively over the period 1990 to 2001.3 Although infectious diseases remain the leading cause of mortality and morbidity in sub-Saharan Africa, the prevalence of cardiovascular disease and hypertension is rising rapidly.4It has been emphasised that urbanisation is a key reason for the increasing rates of hypertension, as evidenced by the higher prevalence of hypertension in urban areas.4-6 Urban lifestyles, characterised by sedentary living, increased salt intake, obesity and stress contribute to these differences.5 With the urban population in sub-Saharan Africa projected to increase, a greater risk of hypertension is anticipated.Studies on the association between ethnicity and hypertension in high-income countries have documented a higher prevalence of hypertension in black ethnic groups compared to white ethnic groups.7-9 Reasons for this association are complex, unclear and much debated, reflecting genetic and biochemical mechanisms, and environmental and socio-economic factors.10,11 There is limited evidence regarding differences in the prevalence of hypertension between ethnic groups within the broader classification of black ethnicity.6,12,13Studies in Nigeria and sub-Saharan Africa have mainly involved specific geographical areas or have focused on sub-groups of the population.5,14 Surveys from Nigeria report prevalence estimates ranging from 20.2 to 36.6%, but all have involved participants with different age ranges.15-18 To plan services for hypertension in Nigeria, it is essential to have accurate prevalence estimates for the whole population and to identify populations at risk.Nigeria, which is the most populous country in sub-Saharan Africa, is home to over 250 different ethnic groups. Nigeria is experiencing rapid urbanisation of the population, which is likely to increase the population at risk for hypertension.19 The present study is one of the largest population-based surveys in the region and is able to provide a nationally representative estimate of hypertension for Nigeria.