Calcium channel blockers for preventing cardiomyopathy due to iron overload in people with transfusion-dependent beta thalassaemia

Long-Term and Transient Calcium Channel Blockers; A Systematic Review of Their Role in the Management of Cardiomyopathy in Transfusion-Dependent Thalassemia

Calcium channel blockers (CCBs) for long-term (L) and transient (T) calcium channels (LTCC and TTCC) on cardiomyocytes have been suggested to manage iron-induced cardiomyopathy in transfusion-dependent thalassemia patients. However, the results of clinical trials on the effectiveness of CCBs have been conflicting. Here, we systematically reviewed previous studies to investigate the potential factors that could act as therapeutic modifiers and explain these discrepancies. This systematic review was conducted employing the PRISMA guideline to retrieve clinical trials and animal studies investigating the efficacy of CCBs. Studies in the following databases were collected: Web of Science, PubMed, Scopus, Google Scholar, Clinical Trials, Iranian Registry for Clinical Trials, and Cochrane CENTRAL. Keywords included the trade and generic names of various CCBs, thalassemia, and cardiomyopathy. Our Primary search resulted in 297 studies, of which 21 (n = 7 trials and n = 14 animal studies) were further analyzed. The most important parameters that could potentially influence the clinical effectiveness of CCBs in managing iron-induced cardiomyopathy included baseline cardiac iron content, diversity of iron entry routes (LTCCs, TTCCs, DMT-1, etc.), type of CCBs used, iron-induced irreversible functional/structural cardiac changes, iron-Ca2+ joint metabolic dysregulation, deregulated expression of LTCCs and TTCCs, interaction of CCBs with iron chelators, disease-related complications, interactions of CCBs with various supplements used by patients, vitamin D and other nutrient deficiencies, and duration of treatment with CCBs. These items should be considered in future trials to draw more robust conclusions about the effectiveness of CCBs in preventing cardiac iron deposition and associated cardiomyopathy in TDT patients.

Combinatorial approach to treat iron overload cardiomyopathy in pediatric patients with thalassemia-major: A systematic review and meta-analysis

BACKGROUND

Iron overload cardiomyopathy is a significant cause of morbidity and mortality in transfusion-dependent thalassemia patients. Standard iron chelation therapy is less efficient in alleviating iron accumulation in many organs, especially when iron enters the cells via specific calcium channels.

AIM

To validate our hypothesis that adding amlodipine to the iron chelation regimen is more efficient in alleviating myocardial iron overload.

METHODS

Five databases, including PubMed, Cochrane Library, Embase, ScienceDirect, and ClinicalTrials.gov, were systematically searched, and three randomized controlled trials involving 144 pediatric patients with transfusion-dependent thalassemia were included in our meta-analysis based on the predefined eligibility criteria. The quality of the included studies was assessed based on the Cochrane collaboration tool for bias assessment. The primary outcome assessed was myocardial-T2 and myocardial iron concentration, while the secondary results showed serum ferritin level, liver iron concentration, and treatment adverse outcomes. Weighted mean difference and odds ratio were calculated to measure the changes in the estimated treatment effects.

RESULTS

During the follow-up period, Amlodipine treatment significantly improved cardiac T2 by 2.79 ms compared to the control group [95% confidence interval (CI): 0.34-5.24, P = 0.03, I 2 = 0%]. Additionally, a significant reduction of 0.31 in myocardial iron concentration was observed with amlodipine treatment compared to the control group [95%CI: -0.38-(-0.25), P < 0.00001, I 2 = 0%]. Liver iron concentration was slightly lower in the amlodipine group by -0.04 mg/g, but this difference was not statistically significant (95%CI: -0.33-0.24, P = 0.77, I 2 = 0%). Amlodipine also showed a non-significant trend toward a reduction in serum ferritin levels (-328.86 ng/mL, 95%CI: -1212.34-554.62, P = 0.47, I 2 = 90%). Regarding safety, there were no significant differences between the groups in the incidence of gastrointestinal upset, hypotension, or lower limb edema.

CONCLUSION

Amlodipine with iron chelation therapy significantly improved cardiac parameters, including cardiac-T2 and myocardial iron, in patients with transfusion-dependent thalassemia without causing significant adverse events but enhancing the efficacy of iron chelation therapy.

Etiology of Drug-Induced Edema: A Review of Dihydropyridine, Thiazolidinedione, and Other Medications Causing Edema

Edema is an accumulation of fluid in the body's tissues that affects millions of Americans yearly. It can affect multiple body parts, for example, the brain or eyes, but often occurs in the periphery, including the feet and legs. Medications, such as dihydropyridine and thiazolidinediones (TZDs), can be the etiology of edema. Edema can develop in association with problems in the vasculature or lymphatic flow. In recent years, a better understanding of these drug-induced mechanisms has been appreciated. Specifically, dihydropyridines can increase hydrostatic pressure and cause selective pre-capillary vessel vasodilation. TZDs can cause edema through increased vascular permeability and increased hydrostatic pressure. Specifically, peroxisome proliferator-activated receptor gamma (PPARγ) stimulation increases vascular endothelial permeability, vascular endothelial growth factor (VEGF) secretion, renal sodium, and fluid retention. Other drugs that can cause edema include neuropathic pain agents, dopamine agonists, antipsychotics, nitrates, nonsteroidal anti-inflammatory (NSAIDS), steroids, angiotensin-converting enzyme (ACE) inhibitors, and insulin. There are various clinical presentations of edema. Since multiple mechanisms can induce edema, it is important to understand the basic mechanisms and pathophysiology of drug-induced edema. Edema can even become fatal. For example, angioedema can occur from ACE inhibitor therapy. In this regard, it is considered a medical emergency when there is laryngeal involvement. This review aims to thoroughly appreciate the multiple causes of drug-induced edema and the ways it can be treated or prevented.