Longitudinal study of echocardiography-derived tricuspid regurgitant jet velocity in sickle cell disease

Role of hydroxyurea therapy in the prevention of organ damage in sickle cell disease: a systematic review and meta-analysis

BACKGROUND

Hydroxyurea is an affordable drug that reduces vaso-occlusive crises and transfusion requirements in sickle cell disease. However, its effectiveness in preventing chronic organ damage is still unclear. This systematic review and meta-analysis aimed to evaluate the role of hydroxyurea in preventing organ morbidity.

METHOD

We included original articles published in English from 1st January 1990 to 31st January 2023, reporting hydroxyurea therapy and organ damage from PubMed, Google Scholar, Scopus, and CrossRef databases. A total of 45 studies with 4681 sickle cell disease patients were evaluated for organ damage.

RESULTS

Our analysis showed that hydroxyurea intervention significantly lowered transcranial Doppler and tricuspid regurgitant velocity, with a standardized mean difference of - 1.03 (- 1.49; - 0.58); I 2 = 96% and - 1.37 (CI - 2.31, - 0.42); I 2 = 94%, respectively. Moreover, the pooled estimate for albuminuria showed a beneficial effect post-hydroxyurea therapy by reducing the risk of albuminuria by 58% (risk ratio of 0.42 (0.28; 0.63); I 2 = 28%).

CONCLUSION

Our study found that a hydroxyurea dose above 20 mg/kg/day with a mean rise in HbF by 18.46% post-hydroxyurea therapy had a beneficial role in reducing transcranial doppler velocity, tricuspid regurgitant velocity, albuminuria, and splenic abnormality.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO CRD42023401187.

Treatment dilemmas: strategies for priapism, chronic leg ulcer disease, and pulmonary hypertension in sickle cell disease

Sickle cell disease is a disorder characterized by chronic hemolytic anemia and multiorgan disease complications. Although vaso-occlusive episodes, acute chest syndrome, and neurovascular disease frequently result in complication and have well-documented guidelines for management, the management of chronic hemolytic and vascular-related complications, such as priapism, leg ulcers, and pulmonary hypertension, is not as well recognized despite their increasing reported prevalence and association with morbidity and mortality. This chapter therefore reviews the current updates on diagnosis and management of priapism, leg ulcers, and pulmonary hypertension.

Computer Algorithm-Based Hydroxyurea Dosing Facilitates Titration to Maximum Tolerated Dose in Sickle Cell Anemia

Adults with sickle cell disease (SCD) experience acute and chronic complications and die prematurely. When taken at maximum tolerated dose (MTD), hydroxyurea prolongs survival; however, it has not consistently reversed organ dysfunction. Patients also frequently do not take hydroxyurea, at least in part because of physician discomfort with prescribing hydroxyurea. We sought to develop a computer program that could easily titrate hydroxyurea to MTD. This was a single-arm, open-label pilot study. Fifteen patients with homozygous SCD were enrolled in the protocol, and 10 patients were followed at baseline and then for 1 year after hydroxyurea initiation or dose titration. Fetal hemoglobin significantly increased in all 10 patients from 8.3% to 25.1% (P < .001). Nine patients were titrated to MTD in an average of 7.9 months, and the tenth patient's hydroxyurea dose was increased to 33 mg/kg/day. Computer program dosing recommendations were the same as manual dosing decisions made using the same algorithm for all patients and at all times. We also evaluated markers of cardiopulmonary, liver and renal damage. Although cardiopulmonary function did not significantly improve, direct bilirubin and alanine aminotransferase levels significantly decreased (P < .001 and P < .01, respectively). Last, although kidney function did not improve, degree of proteinuria was significantly reduced (P < .05). We have developed a computer program that reliably titrates hydroxyurea to MTD. A larger study is indicated to test the program either as a computer program or a downloadable application.

Lower than expected elevated tricuspid regurgitant jet velocity in adults with sickle cell disease in Nigeria

Background

Cardiopulmonary disease is a major cause of morbidity and mortality in persons with sickle cell disease (SCD). Tricuspid regurgitant jet velocity (TRJV) and predicted forced expiratory volume in 1 s (FEV1%) predicted are independently associated with death in SCD. The goal of this study was to determine the prevalence of elevated TRJV and the association, if any, between TRJV and FEV1% predicted among persons with sickle cell anaemia (SCA) in Nigeria.

Methods

Using a cross-sectional design, we enrolled 100 adult Nigerians (≥15 y) with SCA. We screened participants using Doppler echocardiogram to determine their TRJV and assessed their lung function with spirometry.

Results

The prevalence of elevated TRJV was 6%, with 74% of participants having low FEV1% predicted (<70%). TRJV was negatively correlated with FEV1%, but this finding was not statistically significant (Spearman's ρ=-0.0263, p=0.8058).

Conclusions

We found a low prevalence of elevated TRJV and a trend in association between TRJV and FEV1% predicted in Nigerian adults with SCA. Our findings underscore the need to explore further the relationship between SCD and cardiopulmonary disease in adults.

Hydroxycarbamine: from an Old Drug Used in Malignant Hemopathies to a Current Standard in Sickle Cell Disease

While hydroxycarbamide (hydroxyurea, HU) has less and fewer indications in malignant hemopathies, it represents the only widely used drug which modifies sickle cell disease pathogenesis. Clinical experience with HU for patients with sickle cell disease has been accumulated over the past 25 years in Western countries. The review of the literature provides increasing support for safety and efficacy in both children and adults for reducing acute vaso-occlusive events including pain episodes and acute chest syndrome. No increased incidence of leukemia and teratogenicity was demonstrated. HU has become the standard-of-care for sickle cell anemia but remains underused. Barriers to its use should be identified and overcome.

Does hydroxyurea prevent pulmonary complications of sickle cell disease?

A 27-year-old man with sickle cell disease (HbSS) presents to the sickle cell clinic for follow-up after a screening echocardiogram revealed an increased tricuspid regurgitant velocity of 2.7 m/s. He has a history of 2 painful crises per year and has been hospitalized 3 times over the past 10 years for management of painful crises. He had one episode of acute chest syndrome at age 15 that was treated with an RBC exchange transfusion, supplemental oxygen, and intravenous antibiotics; he did not require mechanical ventilation. He has not had additional episodes of acute chest syndrome and does not have a history of stroke, retinopathy, or leg ulcers. The patient has never been treated with hydroxyurea. He wants to know whether hydroxyurea will prevent future pulmonary complications related to sickle cell disease.

Pulmonary hypertension in sickle cell disease: diagnosis and management

The increased survival of patients with sickle cell disease (SCD) into adulthood is associated with an increased incidence of multiorgan dysfunction and a progressive systemic and pulmonary vasculopathy. The high prevalence of an elevated tricuspid regurgitant jet velocity and its association with an increased risk of death in adult patients is well established. However, there has been controversy regarding the prevalence of pulmonary hypertension (PH) and its association with mortality in SCD. Multiple recently published reports demonstrate that PH as diagnosed by right heart catheterization is common in adult SCD patients, with a prevalence of 6%–11%. Furthermore, PH is associated with an increased risk of death in SCD patients. In this chapter, we provide evidence for the high prevalence of PH in SCD and its association with mortality and make recommendations for its evaluation and management. Finally, we provide the rationale for screening for this life-threatening complication in adult patients with SCD.

Reduction of the six-minute walk distance in children with sickle cell disease is correlated with silent infarct: results from a cross-sectional evaluation in a single center in Belgium

Background

The 6-minute walk test (6MWT) is used in adults and children affected by a wide range of chronic diseases to evaluate their sub-maximal exercise capacity. It reflects the global response of various physiological systems in a situation simulating a daily life activity.

Methods

We analyzed factors affecting the 6MWT in 46 Sickle Cell Disease children. Forty-two were treated with hydroxyurea (HU). Patients with normal test (>80% of the age-standardized predicted value) were compared to patients with abnormal test (≤80%). Baseline hematological values, clinical events, cerebrovascular disease, cardio-pulmonary parameters and disease-modifying treatment were compared according to the performance of the test.

Results

Among the 46 patients, 14 had an abnormal 6MWT. In univariate analysis, both groups were similar for biological and clinical data. Six of the 14 patients with an abnormal 6MWT had silent infarct (SI) compared to 6/32 with a normal test (P = 0.09). When excluding chronically transfused patients, 4 of the 11 patients with an abnormal 6MWT had SI compared to 1/26 (P = 0.02). Baseline pulse oximetry was normal in both groups but slightly lower in patients with abnormal 6MWT (P = 0.02). No patient presented exercise-induced desaturation. In multivariate analysis, the only factor associated with abnormal 6MWT was the presence of SI (P = 0.045).

Conclusions

In our cohort of 46 patients characterized by high exposure rate to HU and by the absence of severe cardiopulmonary disease, the sole factor independently associated with 6MWT was the presence of SI. The lower exercise capacity of children with SI may reflect some subclinical neurological impairment as they do not differ by hemoglobin level or cardiopulmonary parameters.