Pulmonary hypertension in Nigerian adults with sickle cell anemia

Pulmonary Hypertension and Left Ventricular Geometric Types in Sickle Cell Anemia

Pulmonary hypertension (PHT) is multifactorial in origin and a major cause of morbidity and mortality in the sickle cell populace. Its correlation with abnormal left ventricular geometric patterns has not been established. Subjects were sickle cell anemic patients of the hematology clinic of a tertiary hospital who gave informed consent. A modified Medical Research Council questionnaire was used to obtain the demographic, anthropometric, and clinical variables of the subjects. Blood samples were taken for hematologic and biochemical analysis. Spirometry, electrocardiography, and echocardiography were done for all subjects. SPSS version 25 was used for analysis. A p ≤0.05 was used for significance. In total 111 subjects with sickle cell anemia were recruited. Male:female ratio was 1:1.4. The prevalence of PHT was 8.1%. Those with PHT were older and had higher blood pressure, lower respiratory rate, higher body mass index, lower estimated glomerular filtration rate, and a higher prevalence of avascular necrosis of the head of femur, stroke, and chest pain. About 2/3 (66.7%) of those with PHT had concentric left ventricular hypertrophy (LVH) whereas none of those with eccentric LVH had PHT. Age, body mass index, systolic blood pressure, aortic root diameter, concentric LVH, serum creatinine, history of stroke, chest pain, and avascular necrosis of the head of femur correlated directly whereas eccentric LVH correlated inversely with PHT. Concentric LVH, relative systemic hypertension, history of chest pain, and respiratory rate were the independent correlates of PHT in subjects with sickle cell anemia. PHT is known to be of poor prognostic significance. Its association with relative systemic hypertension and concentric LVH suggests the need to initiate early treatment to reduce morbidity and mortality in this group.

Pulmonary Hypertension in Children across Africa: The Silent Threat

Pulmonary hypertension (PH) is a complex puzzle in Africa, especially among children who present with a cocktail of issues including recurrent pulmonary infections, unoperated congenital heart disease, and advanced rheumatic heart disease. Sickle cell anemia and neonatal complications of transiting from fetal circulation also contribute to the burden of pulmonary hypertension. Mortality from pulmonary arterial hypertension (PAH) remains high in Africa (18-21%), claiming sufferers in the first 6 months after diagnosis. Unfortunately, PH remains underreported in sub-Saharan Africa since many centers lack the capacity to diagnose and confirm it by the recommended gold standard, right heart catheterization. The unresolved burden of unoperated congenital heart lesions and rheumatic heart disease, among other preventable causes, stand out as major causes of PH in African children. This paper highlights pediatric PAH as a result of major gaps in care and illustrates the need for its prevention as well as for the promotion of research into the most important drivers, to prevent premature mortality in the continent.

Longitudinal effect of disease-modifying therapy on tricuspid regurgitant velocity in children with sickle cell anemia

Elevated tricuspid regurgitant velocity (TRV) ≥2.5 m/s is a predictor of disease severity in adults and children with sickle cell anemia (SCA), but how disease-modifying therapies (DMTs) affect this biomarker is incompletely understood. We investigated the effect of DMTs on TRV elevation in children. In a prospective single-center study, 204 subjects with HbSS or HbSβ0 thalassemia (mean age, 10.6 years; range, 5-18) had echocardiograms with assessment of TRV, with repeat evaluations after 2 years of observation. One-hundred and twelve participants received DMTs (hydroxyurea, n = 72; monthly erythrocyte transfusions, n = 40), 58 did not receive any DMT, and 34 were begun on hydroxyurea during this observation period. In the entire cohort, an increase in hemoglobin of 1.0 g/dL was associated with a 0.03-m/s decrease in TRV (P = .024), and a decrease in absolute reticulocyte count of 1.0 × 106/mL was associated with a 0.34-m/s decrease in TRV (P = .034). Compared with baseline, hydroxyurea exposure (continuous or newly started) was associated with an average 5% decline in mean TRV at the 2-year evaluation. Among participants newly started on hydroxyurea (mean treatment duration 1.2 ± 0.6 years), an increase in hemoglobin of 1.0 g/dL was associated with a 0.06-m/s decrease in TRV (P = .05). We conclude that hydroxyurea therapy may mitigate TRV elevation in children with SCA, possibly as a result of a reduction in hemolysis and improvement in anemia.

Challenges and Special Aspects of Pulmonary Hypertension in Middle- to Low-Income Regions: JACC State-of-the-Art Review

Challenges and special aspects related to the management and prognosis of pulmonary hypertension (PH) in middle- to low-income regions (MLIRs) range from late presentation to comorbidities, lack of resources and expertise, cost, and rare options of lung transplantation. Expert consensus recommendations addressing the specific challenges for prevention and therapy of PH in MLIRs with limited resources have been lacking. To date, 6 MLIR-PH registries containing mostly adult patients with PH exist. Importantly, the global prevalence of PH is much higher in MLIRs compared with high-income regions: group 2 PH (left heart disease), pulmonary arterial hypertension associated with unrepaired congenital heart disease, human immunodeficiency virus, or schistosomiasis are highly prevalent. This consensus statement provides selective, tailored modifications to the current PH guidelines to address the specific challenges faced in MLIRs, resulting in the first pragmatic and cost-effective consensus recommendations for PH care providers, patients, and their families.

Pulmonary hypertension: From an orphan disease to a global epidemic

[No abstract. Showing first paragraph of article]Pulmonary hypertension is a progressive disease characterized by an elevation of pulmonary artery pressure and pulmonary vascular resistance, leading to right ventricular failure and death. It remains a challenging chronic progressive disease, but the current interest and advent of medical therapy in the last 20 years has significantly changed the perception of medical community in this disease. Pulmonary hypertension is not a specific disease; the majority of cases present with other diseases and various pathological processes that affect the pulmonary vasculature, and consequently increase pulmonary pressure and vascular resistance.

Pulmonary vascular disease in Africa: Lessons from registries

The epidemiology of pulmonary vascular disease (PVD) remains unclear in Africa, where health systems do not reach the majority of the population and heath information systems are poorly developed. In this context, registries are particularly important in gathering crucial information on PVD, aiming at improving knowledge of the epidemiology and/or quality of care. While population-based registries are the main tool to identify incident cases, and be a better indicator of pulmonary vascular disease burden, hospital-based registries can give an indication of the demand for specific care services, which is useful for health policy and planning. The only registry for pulmonary hypertension in Africa - the Pan African Pulmonary Hypertension Cohort (PAPUCO) - involved four countries, and was a pragmatic study that revealed a unique pattern of environmental risks, issues related to low access to health care, and ill-equipped health facilities for diagnosis and management of pulmonary hypertension. In addition, disease specific registries for conditions such as congenital heart disease and rheumatic heart disease uncovered high occurrence of PVD that can be managed and/or prevented with improvements in community awareness, surveillance, management and prevention. It is suggested that existing networks of experts and researchers develop regional registries to determine the epidemiology of PVD in Africa, assess geographic, environmental and seasonal differentials, as well as inform policy and care provision in the continent.

Pulmonary hypertension in low- and middle-income countries with focus on sub-Saharan Africa

Pulmonary hypertension (PH) is a devastating, progressive disease with increasingly debilitating symptoms and usually shortened overall life expectancy. This article reviews the global epidemiology of PH with focus on low- and middle-income countries (LMICs) and sub-Sahara African in particular. Although left ventricular heart disease is the most common cause globally, the main contributing risk factors in LMICs are chronic infectious diseases especially human immunodeficiency virus (HIV) and schistosomiasis. Other important risk factors of PH are rheumatic heart disease, untreated congenital heart disease (CHD), and sickle cell disease. Despite existing epidemiological data of PH risk factors suggesting a high prevalence in sub-Saharan Africa (SSA), the available literature is limited. International registries in LMICs like the pan African pulmonary hypertension cohort (PAPUCO) study are essential to provide information about the causes, treatment, outcome, and the natural course of PH in Africa and other parts of the world. In addition, there is a need to track diagnostic and management practices in order to develop suitable algorithms to diagnose PH in LMICs.

Early progression of pulmonary hypertension in the monocrotaline model in males is associated with increased lung permeability

Background

The mechanisms involved in pulmonary hypertension (PH) development in patients and pre-clinical models are poorly understood. PH has a well-established sex dimorphism in patients with increased frequency of PH in females, and more severe disease with poor survival prognosis in males. Previously, we found that heme signaling plays an essential role in the development phase of the Sugen/Hypoxia (SU/Hx) model. This study is focused on the elucidation of sex differences in mechanisms of PH development related to heme action at the early stage of the monocrotaline (MCT) PH model.

Methods

Rats received MCT injection (60 mg/kg, i.p.) and followed for 14 days to investigate early disease changes. Hemodynamic parameters were recorded at the end of the study; plasma, lung homogenates, and nuclear fractions were used for the evaluation of protein levels.

Results

Our data indicate that on day 14, rats did not show any significant increase in the Fulton index due to the early disease phase. However, the right ventricular systolic pressure was significantly increased in male rats, while female rats showed only a trend. Interestingly, only males demonstrated an increased lung-to-bodyweight ratio that indicated lung edema. Indeed, lung histology confirmed severe perivascular edema in males. Previously, we have reported that the increased perivascular edema in SU/Hx model correlated with intravascular hemolysis and activated heme signaling. Here, we found that elevated free hemoglobin levels and perivascular edema were increased, specifically in males showing more rapid progress of PH. A high level of heme carrier protein 1 (HCP-1), which is involved in heme uptake from the bloodstream into the cells, was also found elevated in the lungs of males. The upregulation of heme oxygenase in males indicated increased intracellular heme catabolism. Increased heme signaling resulted in the activation of heme-mediated barrier-disruptive mechanisms. Thus, hemolysis in males can be responsible for increased permeability of the lungs and early disease development.

Conclusions

Our study indicates the importance of barrier-disruptive mechanisms as an earlier event in the induction of pulmonary hypertension. Importantly, males are more susceptible to hemolysis and develop PH earlier than females.

Current perspectives of sickle cell disease in Nigeria: changing the narratives

Introduction: Sickle cell disease (SCD) is an inherited blood disorder characterized by clinical heterogeneity that may be influenced by environmental factors, ethnicity, race, social and economic factors as well as genetic and epigenetic factors. Areas covered: The present review was carried out to provide a comprehensive assessment of the current burden of SCD and treatments available for persons with SCD in Nigeria with the aim of identifying surveillance and treatment gaps, informing to guide the planning and implementation of better crisis prevention measures for SCD patients and set an agenda for new areas of SCD research in the country. This review assessed medical, biomedical and genetic studies on SCD patients in Nigeria and other endemic countries of the world. Expert opinion: Integration of hydroxyurea therapy into the management of SCD and surveillance via new-born screening (NBS) for early detection and management will improve the survival of persons with SCD in Nigeria. However, it will be important to carry out pilot studies, initiate strategic advocacy initiatives to educate the people about NBS benefits, develop collaborations between potential stakeholders and design sustainable financing scheme.

Prevalence and etiologies of pulmonary hypertension in Africa: a systematic review and meta-analysis

BACKGROUND

Despite the recent increasing worldwide attention towards pulmonary hypertension (PH), its epidemiology remains poorly described in Africa. Accordingly, we performed a systematic review and meta-analysis of PH prevalence, incidence and etiologies in Africa.

METHODS

We searched PubMed, EMBASE, African Journals Online, and Africa Index Medicus. Published observational studies until September 20, 2017, including adult participants residing in Africa were considered. Two review authors independently selected studies, assessed included studies for methodological quality, and extracted data. A random-effects model was used for meta-analysis. Heterogeneity was evaluated by the χ 2 test on Cochrane's Q statistic which is quantified by I2 values. Using Newcastle-Ottawa Scale, we considered a score of 0-4, 5-7, and 8-10 as indicative of high, moderate, and low risk of bias in included studies, respectively.

RESULTS

Of 1611 entries, 25 studies were retained. Twelve (48%), seven (28%), and six (24%) papers had respectively a low, moderate and high risk of bias. The prevalence of PH widely varied across different populations: 9.8% (95% confidence interval: 3.2-19.3; I2 = 99.4%; 6 studies) in 11,163 people presenting with cardiac complaints; 10.6% (4.3-19.1; I2 = 90.3%; 4 studies) in 937 HIV-infected people; 32.9% (17.6-50.4; I2 = 97.2%; 3 studies) in 2077 patients with heart failure; 23.2% (15.2-32.2; I2 = 59.4%; 3 studies) in 248 patients on hemodialysis; 12.9% (11.8-14.0; I2 = 79.7%; 2 studies) in 3750 patients with rheumatic heart disease; 36.9% (29.7-44.3; I2 = 79.7; 2 studies) in 79 patients with sickle cell disease; 62.7% (49.0-74.7; 1 study) in 51 patients with chronic obstructive pulmonary disease; 25.4% (16.3-37.3; 1 study) in 63 patients with systemic lupus erythematous; 68.7% (62.8-74.1; 1 study) in 259 patients with cardiac surgery; and 7.4% (4.6-11.9; 1 study) in 202 patients with systemic sclerosis. No study reported PH incidence. From one international study (n = 209), PH etiologies were: left heart disease (68.9%), pulmonary arterial hypertension (15.8%), lung disease and/or hypoxia (12.0%), chronic thromboembolic PH (1.9%) and unclear/multifactorial PH (15.8%).

CONCLUSION

The prevalence of PH is relatively high in some populations in Africa, perhaps mainly driven by left heart diseases, highlighting the need for context-specific interventions.