Recent advances in the diagnosis and management of cardiac amyloidosis

QRS fragmentation and T-wave inversion as factors of vulnerability to recurrent ventricular tachycardia

Clinical manifestation of late onset recurrent monomorphic ventricular tachycardia (VT) in patients with normal left ventricular ejection fraction may elude diagnosis despite elaborate testing. This report describes a 67-year-old woman with structurally normal heart who presented with recurrent VT in the absence of predisposing factors. Repeated extensive diagnostic testing, including magnetic resonance imaging and coronary angiography, did not disclose any abnormality. An implantable cardioverter-defibrillator was placed following noninducibility of the third episode of VT at electrophysiological study. Patient's 12-lead electrocardiogram in normal sinus rhythm revealed permanent QRS fragmentation as well as T-wave inversions as the only warning features that heralded the impending appearance of recurrent VTs over the course of 5 years follow-up.

Multiorgan involvement by amyloid light chain amyloidosis

Amyloid light chain (AL) amyloidosis is a protein conformational disease. AL amyloidosis results from aggregation of misfolded proteins that are deposited in tissues as amyloid fibrils. Diagnosis of AL amyloidosis can be challenging due to its low incidence and clinical complexity. Therapy requires a risk-adapted approach involving dose reductions and schedule modifications of chemotherapy regimens along with close monitoring of hematologic and organ responses. We herein describe a patient whose condition was diagnosed as systemic AL amyloidosis and presented with splenic rupture as the initial symptom. Congo red staining of the kidney biopsy was positive. The normal structure of the liver and spleen had been replaced by amyloid deposition. The chemotherapy strategy involved a combination of bortezomib, cyclophosphamide, thalidomide, and dexamethasone.

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In this article we present brief overview of the subject of amyloidosis and involvement of the cardiovascular system, the criteria for diagnosis, principles of treatment, and the clinical case of cardiac amyloidosis.

Newer Therapies for Amyloid Cardiomyopathy

The heart and the kidneys are the most commonly involved organs in systemic amyloidosis. Cardiac involvement is associated with an increased morbidity, treatment intolerance, and poorer overall survival. The most common types of amyloidosis that are associated with cardiac involvement include light chain (AL) amyloidosis and transthyretin (TTR) amyloidosis (both mutant and wild type). The traditional first-line treatment for AL amyloidosis includes alkylator-based chemotherapy or high-dose melphalan followed by autologous stem cell transplantation (ASCT). Novel agents, including proteasome inhibitors, immunomodulators, and monoclonal antibodies, have shown promising activity in both frontline and relapsed settings. Orthotopic heart transplantation (OHT) followed by ASCT has led to superior outcomes compared to OHT alone. Orthotopic liver transplantation (OLT) is the first-line treatment for TTR amyloidosis. However, progression of cardiac amyloidosis after OLT is often noted due to deposition of wild TTR. Combined OLT and OHT also has a role in treatment and leads to superior outcomes in carefully selected candidates. Pharmacologic agents, including diflunisal, tafamidis, small interfering ribonucleic acid, and doxycycline, have shown promising activity in stabilizing TTR from misfolding into fibrils and are being actively investigated. Best supportive care and management of heart failure symptoms with diuretics are a mainstay of treatment in all cardiac amyloidosis subtypes. Robust data on the benefit of angiotensin-converting enzyme inhibitors, angiotensin receptor blockers, or beta blockers in amyloid cardiomyopathy is lacking.

Diagnostic accuracy of cardiovascular magnetic resonance for patients with suspected cardiac amyloidosis: a systematic review and meta-analysis

Background

This study is a systematic review and meta-analysis of the diagnostic value of cardiovascular magnetic resonance (CMR) in cardiac amyloidosis (CA).

Methods

A wide variety of electronic databases were searched for studies of CMR that reported the diagnostic accuracy in patients with suspected CA. Research manuscripts were subjected to further systematic review and meta-analysis. Methodological evaluation was performed under the guidance of the Quality Assessment of Diagnostic Accuracy Studies −2 (QUADAS–2). Heterogeneity was assessed, and a random-effects model was used to assess the diagnostic effects of CMR on pooled sensitivity, pooled specificity, and summary receiver operating characteristics (SROC).

Results

Seven studies that reported the performance of CMR for CA were included in the present systematic review, among which five studies (257 patients) that evaluated the diagnostic accuracy of late gadolinium enhancement (LGE) CMR were analyzed in the present meta-analysis. Heterogeneity was observed only in specificity. A summary sensitivity and specificity of 85 % (95 % CI: 77–91 %) and 92 % (95 % CI: 83–97 %) indicated a high diagnostic accuracy of LGE for CA. The AUC of SROC curve was 0.9530, suggesting that LGE is an effective way of diagnosing patients with possible cardiac involvement in amyloidosis.

Conclusions

LGE–CMR seems to have a relatively high diagnostic accuracy for amyloidosis patients with possible cardiac involvement. Combined CMR techniques may provide important information for the selection of suitable therapy.

Electronic supplementary material

The online version of this article (doi:10.1186/s12872-016-0311-6) contains supplementary material, which is available to authorized users.

Proteotoxicity and cardiac dysfunction

Baseline physiological function of the mammalian heart is under the constant threat of environmental or intrinsic pathological insults. Cardiomyocyte proteins are thus subject to unremitting pressure to function optimally, and this depends on them assuming and maintaining proper conformation. This review explores the multiple defenses a cell may use for its proteins to assume and maintain correct protein folding and conformation. There are multiple quality control mechanisms to ensure that nascent polypeptides are properly folded and mature proteins maintain their functional conformation. When proteins do misfold, either in the face of normal or pathological stimuli or because of intrinsic mutations or post-translational modifications, they must either be refolded correctly or recycled. In the absence of these corrective processes, they may become toxic to the cell. Herein, we explore some of the underlying mechanisms that lead to proteotoxicity. The continued presence and chronic accumulation of misfolded or unfolded proteins can be disastrous in cardiomyocytes because these misfolded proteins can lead to aggregation or the formation of soluble peptides that are proteotoxic. This in turn leads to compromised protein quality control and precipitating a downward spiral of the cell's ability to maintain protein homeostasis. Some underlying mechanisms are discussed and the therapeutic potential of interfering with proteotoxicity in the heart is explored.

Biomarkers of fatigue related to adjuvant chemotherapy for breast cancer: evaluation of plasma and lymphocyte expression

Background

Fatigue is common in cancer patients receiving adjuvant chemotherapy. To further understand the mechanism of fatigue and search for potential biomarkers, we conducted this prospective study. Methods

We enrolled breast cancer (BC) patients before their first adjuvant Adriamycin-based chemotherapy cycle. Patients responded to the brief fatigue inventory (BFI) and Chalder fatigue questionnaires and had their blood drawn for both plasma evaluation and evaluation of the peripheral mononuclear cell fraction (PMNCF) mRNA expression of various biomarkers. We evaluated FSH, LH, estradiol, DHEA, DHEAS, IL6, IL2, ILIRA, IL1β, CRP, Cortisol in the plasma and IL2, IL10, IL6, TGF-β, KLRC1, TNF, BTP, SNCA, SOD1, BLNK, PTGS2 and INF γ expression in the PMNCF.

Results

11 patients did not exhibit an increase in their BFI scores and served as controls, whereas 32 patients exhibited an increase in their BFI scores compared with the baseline scores. From the biomarkers we evaluated in the PMNCF, the only one significantly associated with fatigue was TGF-β (p = 0.0343), while there was a trend towards significance with KLRC1 (p = 0.0627). We observed no evidence of significant associations of any plasma biomarkers with the development of fatigue. However when we analyzed patients with more severe fatigue, plasma IL1-RA levels correlated directly with higher fatigue scores (p = 0.0136).

Conclusions

We conclude that fatigue induced by chemotherapy in BC patients is associated with changes in IL1-ra plasma levels and in TGF-β lymphocyte expression. Its mechanism may be different than that observed in long-term BC survivors or that induced by radiation therapy.

Trial registration

NCT02041364 [ClinicalTrials.gov]