Do automated red cell exchanges relieve priapism in patients with sickle cell anemia?

What is the effectiveness of surgical and non-surgical therapies in the treatment of ischemic priapism in patients with sickle cell disease? A systematic review by the EAU Sexual and Reproductive Health Guidelines Panel

Sickle cell disease (SCD) is an inherited hemoglobin disorder characterized by the occlusion of small blood vessels by sickle-shaped red blood cells. SCD is associated with a number of complications, including ischemic priapism. While SCD accounts for at least one-third of all priapism cases, no definitive treatment strategy has been established to specifically treat patients with SC priapism. The aim of this systematic review was to assess the efficacy and safety of contemporary treatment modalities for acute and stuttering ischemic priapism associated with SCD. The primary outcome measures were defined as resolution of acute priapism (detumescence) and complete response of stuttering priapism, while the primary harm outcome was as sexual dysfunction. The protocol for the review has been registered (PROSPERO Nr: CRD42020182001), and a systematic search of Medline, Embase, and Cochrane controlled trials databases was performed. Three trials with 41 observational studies met the criteria for inclusion in this review. None of the trials assessed detumescence, as a primary outcome. All of the trials reported a complete response of stuttering priapism; however, the certainty of the evidence was low. It is clear that assessing the effectiveness of specific interventions for priapism in SCD, well-designed, adequately-powered, multicenter trials are strongly required.

Red blood cell exchange in an emergency in sickle cell disease

Red blood cell exchange (RBCEx) has become a standard therapy to remove abnormal red blood cells (RBCs) in patients with sickle cell disease (SCD). In the last few decades, numerous RBCEx procedures have been performed chronically during regular programs, while numerous procedures have also been performed in an emergency for several indications, this therapeutic option being very efficient in vital and emergency situations. In both groups of indications, large amounts of sickle RBCs have to be removed, which requires great precision and the setting of specific hematological targets. The aim of this review is to discuss the aims, clinical and biological targets, and the requirements and precautions when performing RBCEx in an emergency. Moreover, we analyze how improvement of the techniques as well as the clinical and biological targets has led to optimization of the procedures in emergency settings. We also consider the outstanding issues that require additional investigation.

Recommendations for the use of red blood cell exchange in sickle cell disease

Sickle cell disease (SCD) is a genetic disorder characterised by a single mutation of the beta globin gene, causing the production of an abnormal haemoglobin called sickle haemoglobin (HbS). In its deoxygenated form, HbS polymerises, causing major rheological disorders, which presents clinically as periodic vaso-occlusive crises, chronic haemolysis and chronic vascular dysfunction. Patients often resort to a background treatment, and transfusion remains the cornerstone in the management of the disease, significantly reducing morbidity and mortality. The aim of red blood cell exchange (RBCX) is to improve tissue oxygenation by increasing haemoglobin levels while lowering HbS levels. RBCX can be performed by manual or automated exchange, and each technique has its own set of advantages and disadvantages. This article will outline the transfusion indications for the main complications of SCD, as well as the most appropriate strategy to use.

Red cell exchange: special focus on sickle cell disease

The primary function of red blood cells (RBCs) is to deliver oxygen from the lungs to tissues. Tissue hypoxia occurs when the oxygen-carrying capacity of RBCs is compromised due primarily to 3 causes: (1) a reduction in circulating RBC mass, (2) an increase in circulating RBC mass, or (3) abnormal hemoglobin (Hb) that either does not sufficiently release oxygen to tissues (high-oxygen-affinity hemoglobin) or occludes the microvasculature due to deformed RBCs (sickled RBCs). To improve oxygenation in patients with reduced or increased RBC mass, RBC administration (simple transfusion) or RBC removal (RBC depletion) is performed, respectively. However, for patients with abnormal Hb, RBCs containing abnormal Hb are removed and replaced by healthy volunteer donor RBCs by red cell exchange (RCE). RCE can be performed by manual exchange or by automated exchange using a blood cell separator (erythrocytapheresis). In this review, indications for RCE in sickle cell disease using the evidence-based American Society for Apheresis categories(1) are presented and the rationale for RCE in each disorder are discussed. Simple transfusion versus RCE and manual RCE versus automated RCE are compared. Finally, this review briefly presents some of the challenges of performing erythrocytapheresis in small children and discusses various choices for central venous access during RCE.(2.)

Priapism in homozygous sickle cell patients: important clinical and laboratory associations

OBJECTIVE

To evaluate the relationship between the occurrence of priapism and important steady-state clinical and laboratory parameters in homozygous sickle cell disease (SCD).

SUBJECTS AND METHODS

Steady-state clinical and laboratory data were obtained from the medical records of 126 male patients seen in the clinic over a 7-year period. Estimated prevalence rates, correlation coefficients and independent t tests were calculated to assess the relationship between priapism and several important clinical and laboratory indices. Patient data on age, haemoglobin concentrations, the frequency of crises per annum, leucocyte counts, platelet counts, serum bilirubin and aspartate transaminase were evaluated.

RESULTS

The prevalence of priapism was determined to be 21.4%, and 22.2% of those affected had erectile dysfunction. There was a significant positive correlation between priapism and older age (p = 0.049) and lower leucocyte counts (p = 0.008). There was no significant relationship with other clinical or laboratory indices.

CONCLUSION

About 1 in 4 of all homozygous older SCD patients had priapism, and an approximately similar ratio developed erectile dysfunction; they also had lower steady-state leucocyte counts. Other clinical and laboratory indicators of disease severity in SCD did not positively correlate with the occurrence of priapism, and this may imply an alternative pathogenetic mechanism.

How I manage priapism due to sickle cell disease

Priapism due to sickle cell disease is a common but less well characterized complication of the disorder. It represents a "medical emergency" with the key determinant of outcome being the duration of penile ischaemia and time to detumescence of <4 h associated with a successful treatment outcome. Management can be outpatient-based and consists of pre-emptive strategies for early stuttering attacks based on prior health education of the association between the 2 disorders, non pharmacological management, outpatient penile aspiration and irrigation with or without instillation of alpha and beta adrenergic agonists for acute episodes and secondary prophylaxis to prevent the high rates of recurrences. The evidence to recommend medical prophylaxis is sparse but based on a consensus of experts and small phase 2 or III clinical trials. A clearer understanding of the molecular mechanism(s) involving normal and dysregulated erectile physiology, scavenger haemolysis and nitric oxide pathway paves way for the use of phosphodiesterase type 5 inhibitors in medical prophylaxis of stuttering attacks. These agents will need to be studied in multi-centre randomized phase III trials before they become standard of care. A multidisciplinary team approach is required to enhance "sexual wellness" and prevent erectile dysfunction in this sexually vulnerable group.

Treatment of Priapism with Automated Red Cell Exchange and Hyperbaric Oxygen in an 11-year-old Patient with Sickle Cell Disease

Priapism affects up to 50% of all males with sickle cell disease, and there is no standard treatment. Delayed and unsuccessful treatment leads to corporal fibrosis and impotence. It is therefore necessary to determine the best treatment methods for this complication in order to offer effective interventions to all affected patients. Herein we report an 11-year-old patient with sickle cell disease that presented with priapism 72 h after onset, and was successfully treated with automated red cell exchange and hyperbaric oxygen following unsuccessful surgical and conventional interventions.

Assessment of corrected QT interval in sickle-cell disease patients who undergo erythroapheresis

Extension of the QT interval is characterized by syncope and cardiac arrest and often occurs in association with medical therapies and procedures. Whether erythroapheresis (EPH) could influence the QT interval duration in patients with sickle cell disease (SCD) is not known. We aimed to investigate the effects of EPH on the heart rate-corrected QT (QTc) interval. The study included 25 patients with SCD who underwent 34 EPH procedures. Two independent observers measured QTc interval duration from electrocardiograms performed continuously for 3 min at three different points during the EPH procedures (prior to EPH, after completion of 50% EPH and 15 min after EPH). Multiple regression analysis was used to determine if the ionized plasma calcium, the level of plasma magnesium, citrate infusion rate and painful crisis significantly contributed to the QTc interval. There was a non-significant trend (P = 0.184) towards increased QTc in sickle cell patients during EPH compared with pre-EPH values. QTc prolongation (>440 ms) occurred in 72% of the procedures. Fifty percent QTc values returned to baseline after the procedure. The independent variables were not significantly associated with QTc interval. Exchange procedures can induce QTc prolongation in patients with SCD.

[Therapeutic erythrocytapheresis: technical aspects and clinical applications]

PURPOSE

Therapeutic erythrocytapheresis is a selective red cell-depletion aphaeresis technique.

CURRENT KNOWLEDGE AND KEY POINT

Using a discontinuous or continuous flow blood cell separator, the technique safely allows quickly and automatically collecting a large volume of red cells. The main obstacle of implementation is a poor peripheral venous access. The procedure is well-tolerated. Polycythemia vera, hereditary hemochromatosis, complicated sickle-cell-disease and retinal venous occlusion are the main clinical applications.

PROSPECT AND PROJECT

Therapeutic erythrocytapheresis is a more modern and more effective method than the classic patient-bleeding. It has to be preferred in the early treatment of patients with polycythemia vera and hereditary hemochromatosis.

Platelet P-selectin expression in patients with sickle cell disease who undergo apheresis

Activated platelets have been identified in patients with sickle cell disease. However, the association of platelet P-selectin expression and automated red cell exchange procedures in these patients is not well known. We hypothesized that altered whole platelet P-selectin expression is associated with automated red cell exchange. Flow cytometric quantification of platelet P-selectin expression was carried out in 23 patients with sickle cell disease before and after automated red cell exchange. P-selectin expression was quantified as a binding index for platelet P-selectin (the percentage of positive platelets multiplied by the mean fluorescence of positive platelets). The patients were divided into two groups: individuals with painful vaso-occlusive crises (four women and five men; group 1) and those in a steady state (six women and eight men; group 2). The 33 exchange procedures were evaluated prospectively and used acid-citrate-dextrose A solution (whole blood to anticoagulant ratio = 14:1). Platelet P-selectin expression did not significantly change after automated red cell exchange. Clinical factors such as the volume of replacement fluid and the citrate infusion rate did not correlate with postapheresis platelet P-selectin expression. In addition, the association of platelet P-selectin expression and automated red cell exchange was independent of other laboratory factors (hematocrit level, hemoglobin S level, platelet count, and nitric oxide level). Finally, the difference between the study groups regarding platelet P-selectin expression before and after apheresis was insignificant. In conclusion, automated red cell exchange procedures do not induce platelet P-selectin expression in patients with sickle cell disease in the steady state or in vaso-occlusive crisis.

Automated red cell exchange procedures in patients with sickle cell disease

In automated red cell exchange, about 60% of the patient's red blood cells are exchanged via apheresis for those of the donor. We report the outcome of 83 patients with sickle cell anemia (48 women and 35 men; age range, 17-49 years) who underwent a total of 196 apheresis procedures between December 2003 and October 2006 at our institution. We found that automated red cell exchange involving a reduced citrate infusion rate may provide benefit in the prevention or treatment of vaso-occlusive complications in patients with sickle cell disease and may be associated with protean effects on biochemical dynamics.

Transfusion Management in Sickle Cell Disease

Sickle cell disease (SCD) is the most commonly inherited hemoglobinopathy in the United States. Blood transfusion is a critical part of the multidisciplinary approach necessary in the management of SCD; however, blood transfusions are not without complications. The successful use of transfusion as a treatment strategy in SCD requires the critical review and knowledge of transfusion methods, generally accepted indications, clinical situations in which transfusion generally is not considered, the selection of blood products, and strategies to prevent transfusion-related complications.

Association of single nucleotide polymorphisms in klotho with priapism in sickle cell anaemia

The complications of sickle cell disease are probably determined by genes whose products modify the pathophysiology initiated by the sickle haemoglobin mutation. Priapism, one vaso-occlusive manifestation of sickle cell disease, affects more than 30% of males with the disease. We examined the possible association of single nucleotide polymorphisms (SNPs) in 44 candidate genes of different functional classes for an association with the occurrence of priapism. One hundred and forty-eight patients with sickle cell anaemia and incident or a confirmed history of priapism were studied, along with 529 controls that had not developed priapism. Polymorphisms in the KLOTHO gene (KL; 13q12) showed an association with priapism by genotypic [reference SNP cluster identifier number (rs)2249358; odds ratio (OR) = 2.6 (1.4-5.5); rs211239; OR = 1.7 (1.2-2.6)] and haplotype analyses [rs211234 and rs211239; OR = 2.3 (1.5-3.4)]. These findings may have broader implications in sickle cell disease, as KL encodes a membrane protein that regulates many vascular functions, including vascular endothelial growth factor expression and endothelial nitric oxide release.

Follow-up of sickle cell disease patients with priapism treated by hydroxyurea

Hydroxyurea is one of the most successfully used therapies for sickle cell disease. Results of many clinical trials point to hydroxyurea administration for patients with frequent painful crises and acute chest syndrome. Priapism is one of the complications that could be prevented by hydroxyurea, but there are few reports demonstrating the results. Since November 1993, hydroxyurea has been used in our clinic for preventing priapism in patients with stuttering or major attacks who are still capable of achieving intercourse on demand. Five patients were enrolled in the study, and 4 cases benefited by this treatment. After the initial treatment for the acute attack, all five patients developed stuttering priapism. Hydroxyurea was then introduced at the initial dose of 10 mg/kg, and as the hydroxyurea dosage increased, the number or length of priapism episodes decreased. One to two months after the maximal dose (20-35 mg/kg) was introduced, the episodes disappeared. In two patients, we were forced to administer over 30 mg hydroxyurea/kg to abort the episodes, and, in another patient, 25 mg/kg was necessary. All patients present normal sexual activity. Hydroxyurea was discontinued in two patients, but stuttering priapism reappeared. Hydroxyurea was then re-introduced, and priapism disappeared. One patient, using 20 mg hydroxyurea/kg, had a 6-year remission of priapism after hydroxyurea administration; however, he experienced stuttering priapism, 1 month before a major attack, that progressed to impotence. During that month, he did not seek medical attention. In conclusion, the data here presented suggests that hydroxyurea may prevent priapism attacks in sickle cell disease, probably at higher doses than usually prescribed for painful crisis prevention.

The role of red blood cell exchange transfusion in the treatment and prevention of complications of sickle cell disease

Patients with sickle cell disease have abnormal red blood cells (RBCs). This can cause chronic hemolytic anemia and vaso-occlusion leading to tissue hypoxemia and organ dysfunction. RBC exchange transfusion can, without increasing the whole-blood viscosity, quickly replace abnormal erythrocytes with normal and raise the hematocrit resulting in improved delivery of oxygen to hypoxic tissues. Unfortunately, transfusion can also be associated with complications. This paper reviews the role of transfusion, both simple and exchange, in the treatment and prevention of sickle-related complications. The benefits of exchange versus simple transfusion and transfusion versus alternative therapies are discussed.