Effect of beta-blockade on mortality in patients with cardiac amyloidosis: A systematic review and meta-analysis.

AIMS: The efficacy of beta-blockers in cardiac amyloidosis (CA) is unclear, and concerns persist that neurohormonal blockade could worsen symptoms of heart failure. We aimed to assess whether beta-blocker therapy is associated with improved survival in patients with CA. METHODS AND RESULTS: We conducted a systematic review and meta-analysis to examine the impact of beta-blocker therapy on mortality in patients with CA. A search of MEDLINE and EMBASE was performed in August 2023. Data were extracted from observational studies and synthesized with pooling and random effects meta-analysis. Thirteen studies including 4215 patients with CA were incorporated in this review (3688 transthyretin amyloid cardiomyopathy (ATTR-CM), 502 light chain amyloid cardiomyopathy (AL-CM), 25 not specified; age 74.8 ± 5.5 years, 76% male). Over half of the cohort (52%) received beta-blockers and the rate of beta-blocker withdrawal was 28%. All-cause mortality was 33% (range: 13-51%) after a median follow-up ranging from 13 to 36 months. There was an inverse association between the pooled risk of mortality and the use of beta-blocker therapy at any time point (RR 0.48, 95% CI 0.29-0.80, I2 = 83%, P = 0.005, seven studies). There was no association between mortality and beta-blocker use (RR 0.65, 95% CI 0.29-1.47, I2 = 88%, P = 0.30) in the three studies that only included patients with ATTR-CM. The three studies that included patients with both ATTR-CM and AL demonstrated an association of beta-blocker use with reduced mortality (OR 0.43, 95% CI 0.29-0.63, I2 = 4%, P < 0.001). The only study that solely included 53 patients with AL-CM, demonstrated improved survival among the 53% who were able to tolerate beta-blocker therapy (RR 0.26, 95% CI 0.08-0.79, P = 0.02). The absence of information on staging of CA is an important limitation of this study. CONCLUSIONS: Treatment with beta-blockers may be associated with a survival benefit in patients with CA, but these findings are subject to selection and survivor biases. Definitive prospective randomized trials of conventional heart failure therapies are needed in CA.

Extending the reach of expert amyloidosis care: A feasibility study exploring the staged implementation of a UK amyloidosis network.

There has been an exponential increase in the diagnosis of transthyretin amyloid cardiomyopathy (ATTR-CA). In response, the Midlands Amyloidosis Service was launched with the aim of providing patients with a timely diagnosis, remote expertise from the National Amyloidosis Centre and access to emerging transthyretin (TTR)-directed therapies. This was a descriptive study of a pilot hub-and-spoke model of delivering specialist amyloidosis care. Patients with suspected amyloidosis were referred from the wider Midlands region, and seen in a consultant-led multidisciplinary clinic. The diagnosis of ATTR-CA was established according to either the validated non-biopsy criteria or histological confirmation of ATTR deposits with imaging evidence of amyloid. Study endpoints were the volume of service provision and the time to diagnosis from the receipt of referral. Patients (n=173, age 75±2 years; male 72 %) were referred between 2019 and 2021. Eighty patients (46 %) were found to have cardiac amyloidosis, of whom 68 (85 %) had ATTR-CA. The median time from referral to diagnosis was 43 days. By removing the need for patients to travel to London, an average of 187 patient-miles was saved. Fifteen (9 %) patients with wild-type ATTR-CA received tafamidis under the Early Access to Medicine scheme; 10 (6 %) were enrolled into phase 3 clinical trials of RNA interference or antisense oligonucleotide therapies. Our results suggest that implementing a UK amyloidosis network appears feasible and would enhance equity of access to specialised amyloidosis healthcare for the increasing numbers of older patients found to have ATTR-CA.

Urinary retinol binding protein predicts renal outcome in systemic immunoglobulin light-chain (AL) amyloidosis.

Renal risk stratification in systemic immunoglobulin light-chain (AL) amyloidosis is according to estimated glomerular filtration rate (eGFR) and urinary protein creatinine ratio (uPCR), the latter attributed to glomerular dysfunction, with proximal tubular dysfunction (PTD) little studied. Urinary retinol binding protein 4 (uRBP), a low molecular weight tubular protein and highly sensitive marker of PTD, was prospectively measured in 285 newly diagnosed, untreated patients with systemic AL amyloidosis between August 2017 to August 2018. At diagnosis, the uRBP/creatinine ratio (uRBPCR) correlated with serum creatinine (r = 0·618, P < 0·0001), uPCR (r = 0·422, P < 0·0001) as well as both fractional excretion of phosphate and urate (r = 0·563, P < 0·0001). Log uRBPCR at diagnosis was a strong independent predictor of end-stage renal disease {hazard ratio [HR] 2·65, [95% confidence interval (CI) 1·06-6·64]; P = 0·038}, particularly in patients with an eGFR >30 ml/min/1.73 m2 [HR 4·11, (95% CI 1·45-11·65); P = 0·008] and those who failed to achieve a deep haematological response to chemotherapy within 3 months of diagnosis [HR 6·72, (95% CI 1·83-24·74); P = 0·004], and also predicted renal progression [HR 1·91, (95% CI 1·18-3·07); P = 0·008]. Elevated uRBPCR indicates PTD and predicts renal outcomes independently of eGFR, uPCR and clonal response in systemic AL amyloidosis. The role of uRBPCR as a novel prognostic biomarker merits further study, particularly in monoclonal gammopathies of renal significance.

Renal outcome in patients with newly diagnosed multiple myeloma: results from the UK NCRI Myeloma XI trial.

Renal injury is a common complication of multiple myeloma (MM) and is associated with adverse outcome. Despite this, the natural history of renal injury in patients with MM remains uncertain especially in the context of intensive therapy and novel therapies. To address the lack of data, we evaluated the renal function of 2334 patients from the UK National Cancer Research Institute Myeloma XI trial at baseline and at 12 months to assess renal function over time and the factors associated with change. Patients who had severe acute kidney injury or a requirement for dialysis were excluded. At 12 months of the 1450 evaluable patients planned for autologous transplantation; 204 (14%) patients had a decline in estimated glomerular filtration rate (eGFR) ≥25% from baseline, 341 (23.5%) had an improvement and 905 (62%) had no significant change in eGFR. Renal outcome at 12 months for the 884 evaluable patients who were not planned for transplant was similar. Improved renal function was more likely if patients were <70 years old, male, had an average eGFR <60 mL per minute per 1.73 m2 and a higher baseline free light chain level >1000 mg/L, and/or a free light chain response of >90%. It did not correlate with monoclonal-protein response, transplantation, or use of a bortezomib-based regimen. We show that with current therapies the proportion of patients who have a significant decline in renal function in the first 12 months is small. The greatest relative improvement in eGFR is seen in patients with high free light chain at baseline and a high light chain response. This trial was registered at http://www.isrctn.com as #49407852.

Post-transplant Monoclonal Gammopathy of Renal Significance: A Case Series.

Monoclonal gammopathy of renal significance (MGRS) is a new concept with evolving evidence for treatment. MGRS in the transplant kidney is a rare cause of renal transplant dysfunction that can lead to graft loss. Most cases of post-transplant MGRS are due to recurrent disease. Clone-specific chemotherapy is required to target the underlying clone, and this may improve graft survival; however, this can be challenging, as most patients are elderly with age-related comorbidities and may have complications associated with increasing immunosuppression. Here, we report 3 cases of renal allograft MGRS, and each case highlights different challenges in the diagnosis and management of this condition.

Cardiorenal AL amyloidosis: risk stratification and outcomes based upon cardiac and renal biomarkers.

Systemic AL amyloidosis is a cause of type 5 cardiorenal syndrome. Response to treatment is currently reported according to organ-specific amyloidosis consensus criteria (ACC), which are not validated in cardiorenal AL amyloidosis. Of 1000 patients prospectively enrolled into the UK ALchemy study, 318 (32%) had combined cardiac and renal amyloidotic organ dysfunction at diagnosis, among whom 199 (63%) died; median survival by Kaplan-Meier analysis was 18·5 months. Fifty (16%) patients required renal replacement therapy (RRT). At diagnosis, independent predictors of death and dialysis were N-terminal pro-B-type natriuretic peptide (NT-proBNP) >8500 ng/l (hazard ratio [HR] 3·30, P < 0·001; HR 3·00, P < 0·001), and estimated glomerular filtration rate (eGFR) < 30 ml/min/1·73 m2 (HR 1·89, P = 0·011; HR 6·37, P < 0·001). At 6 months, an increase in NT-proBNP of >30% and a reduction in eGFR of ≥25% were independent predictors of death (HR 2·17, P = 0·009) and dialysis (HR 3·07, P = 0·002), respectively. At 12 months, an increase in NT-proBNP >30% was highly predictive of death (HR 3·67, P < 0·001) and dialysis (HR 2·85, P = 0·010), whereas ACC renal response was predictive of neither. Cardiorenal AL amyloidosis is associated with high early mortality. Outcomes are dictated by NT-proBNP and eGFR at diagnosis rather than proteinuria, and thereafter predominantly by changes in NT-proBNP concentration.

Successful Renal Outcome in Membranoproliferative Glomerulonephritis Following Treatment of the Underlying Subtle Clone: A Case Report.

Membranoproliferative glomerulonephritis (MPGN) secondary to a monoclonal gammopathy is a rare glomerular disease and is defined as a monoclonal gammopathy of renal significance. The disease is characterized by glomerular monotypic immunoglobulin deposits and specific changes on light microscopy and electron microscopy. Immunochemistry is required to establish monoclonality, and electron microscopy helps to characterize the deposits ultrastructurally. Investigation for the underlying monoclonal protein should be done. We report a case of MPGN secondary to monoclonal gammopathy of renal significance that responded to treatment of the underlying clone with chemotherapy, resulting in improvement in renal function. Patients with MPGN and immunoglobulin deposition should be evaluated for a monoclonal protein to guide the management strategy.

Serum free light chain levels and renal function at diagnosis in patients with multiple myeloma.

BACKGROUND: Renal impairment (RI) is common in multiple myeloma (MM) and is associated with poor survival. This study reports the associations between renal function and disease characteristics including serum free light chain (FLC) level at diagnosis in patients with MM. METHODS: Using data from the Medical Research Council Myeloma IX trial, a multicentre, randomized, open-label, phase III and factorial-design trial, we assessed the relationships between renal function, demographic, and disease characteristics, including serum FLC levels, in 1595 newly diagnosed MM patients. Multivariable linear regression was utilised to identify factors that were associated with renal function at diagnosis. A receiver operating characteristic curve (ROC) was used to identify the optimal threshold for serum FLC level at diagnosis to predict severe RI. RESULTS: 52.8% of patients had an estimated glomerular filtration rate (eGFR) ≥60 ml/min/1.73 m2 (no RI), 37.3% an eGFR 30-59 ml/min/1.73 m2 (mild to moderate RI), and 9.8% an eGFR < 30 ml/min/1.73 m2 (severe RI). In a multivariable analysis, factors independently and negatively associated with eGFR at diagnosis were: higher serum FLC level, female gender, and older age. Elevated serum FLC level at diagnosis, irrespective of the paraprotein type, was strongly associated with severe RI. Receiver operating characteristic curve analysis showed a serum FLC level of > 800 mg/L as the optimal cut-off associated with severe RI (area under curve 0.86, 95% confidence interval 0.77-0.84). CONCLUSION: There was a strong relationship between higher serum FLC levels at diagnosis and the severity of RI that was irrespective of the paraprotein type. We report an increased risk of severe RI in patients presenting with serum FLC levels above 800 mg/L at diagnosis.

Facing the facts: The Runx2 gene is associated with variation in facial morphology in primates.

The phylogenetic and adaptive factors that cause variation in primate facial form-including differences among the major primate clades and variation related to feeding and/or social behavior-are relatively well understood. However, comparatively little is known about the genetic mechanisms that underlie diversity in facial form in primates. Because it is essential for osteoblastic differentiation and skeletal development, the runt-related transcription factor 2 (Runx2) is one gene that may play a role in these genetic mechanisms. Specifically, polymorphisms in the QA ratio (determined by the ratio of the number of polyglutamines to polyalanines in one functional domain of Runx2) have been shown to be correlated with variation in facial length and orientation in other mammal groups. However, to date, the relationship between variation in this gene and variation in facial form in primates has not been explicitly tested. To test the hypothesis that the QA ratio is correlated with facial form in primates, the current study quantified the QA ratio, facial length, and facial angle in a sample of 33 primate species and tested for correlation using phylogenetic generalized least squares. The results indicate that the QA ratio of the Runx2 gene is positively correlated with variation in relative facial length in anthropoid primates. However, no correlation was found in strepsirrhines, and there was no correlation between facial angle and the QA ratio in any groups. These results suggest that, in primates, the QA ratio of the Runx2 gene may play a role in modulating facial size, but not facial orientation. This study therefore provides important clues about the genetic and developmental mechanisms that may underlie variation in facial form in primates.

Changing epidemiology of AA amyloidosis: clinical observations over 25 years at a single national referral centre.

OBJECTIVE: Systemic AA amyloidosis is a serious complication of chronic inflammation; however, there are relatively few published data on its incidence. We investigated the changing epidemiology of AA amyloidosis over a 25-year period at a single national referral centre. METHODS: We conducted a retrospective study of all patients diagnosed with AA amyloidosis who had attended the centre between 1990 and 2014 inclusive. Six hundred and twenty-five patients were studied in three cohorts: C1: 1990-1997; C2: 1998-2006; C3: 2007-2014. RESULTS: Mean age at presentation increased from 46 in C1 to 56 in C3 (p < .0001). The proportion of South Asian patients increased from 4% in C1 to 17% in C3 (p = .0006). Comparison of underlying diseases between C1 and C3 revealed a reduction in patients with juvenile idiopathic arthritis from 25% to 2% (p < .0001), but an increase in patients with chronic infection due to intravenous recreational drug use from 1% to 13% (p < .0001), and uncharacterized inflammatory disorders from 10% to 27% (p <.0001). More patients were in end-stage renal failure at presentation in C3 (29%) than C1 (15%) (p = .0028). Median age at death was later in C3 (62 years) than C1 (54 years) (p = .0012). CONCLUSION: These data suggest both falling incidence and better outcome in AA amyloidosis over a quarter of a century, reflecting advances in therapeutics and overall management of complex chronic disease in an ageing population. AA amyloidosis of uncertain aetiology presents an emerging major problem. Newer techniques such as next-generation sequencing may aid diagnosis and effective treatment, thereby improving overall survival.

Multiple myeloma can be accurately diagnosed in acute kidney injury patients using a rapid serum free light chain test.

BACKGROUND: Acute kidney injury (AKI) is common in patients with multiple myeloma (MM). Whether serum free light chain (sFLC) measurements can distinguish between myeloma and other causes of AKI requires confirmation to guide early treatment. A rapid and portable sFLC test (Seralite®) is newly available and could reduce delays in obtaining sFLC results and accelerate diagnosis in patients with unexplained AKI. This study evaluated the accuracy of Seralite® to identify MM as the cause of AKI. METHOD: sFLCs were retrospectively analysed in patients with AKI stage 3 as per KDIGO criteria (i.e. serum creatinine ≥354 µmol/L or those on dialysis treatment) (n = 99); 45/99 patients had a confirmed MM diagnosis. RESULTS: The Seralite® κ:λ FLC ratio accurately diagnosed all MM patients in the presence of AKI: a range of 0.14-2.02 returned 100% sensitivity and specificity for identifying all non-myeloma related AKI patients. The sFLC difference (dFLC) also demonstrated high sensitivity (91%) and specificity (100%): an optimal cut-off of 399 mg/L distinguished between myeloma and non-myeloma AKI patients. We propose a pathway of patient screening and stratification in unexplained AKI for use of Seralite® in clinical practice, with a κ:λ ratio range of 0.14-2.02 and dFLC 400 mg/L as decision points. CONCLUSIONS: Seralite® accurately differentiates between AKI due to MM and AKI due to other causes in patients considered at risk of myeloma. This rapid test can sensitively screen for MM in patients with AKI and help inform early treatment intervention.

Prolonged renal survival in light chain amyloidosis: speed and magnitude of light chain reduction is the crucial factor.

Renal involvement causing progressive chronic kidney disease (CKD) is present in 70% of patients with systemic Ig light-chain (AL) amyloidosis at diagnosis. Chemotherapy that substantially suppresses free light chain production is associated with improved patient survival, but its benefit in delaying the onset of renal replacement therapy among patients who present with established advanced CKD has not been studied. To evaluate this, we studied 1000 patients enrolled in the prospective UK AL amyloidosis chemotherapy study (ALchemy). Of these, 84 patients had advanced amyloid-related CKD defined by an estimated glomerular filtration rate (eGFR) under 20 ml/min/1.73 m2. We determined outcomes among these 84 patients, who had a median eGFR of 10 ml/min/1.73 m2, in relation to response to chemotherapy evaluated at three, six, and 12 months from baseline. Patients who achieved suppression of 90% or more in their amyloidogenic free light chain (dFLC) within three months of baseline had significantly better overall survival, prolonged time to dialysis, and prolonged time to the composite endpoint of 'death or dialysis' compared to those who achieved lesser degrees of clonal response at the same time point. Even when this target of greater than 90% dFLC response was achieved but was delayed beyond 3 months, it was associated with worse outcomes. Cox regression analyses confirmed that a 90% or better dFLC response within 3 months was the only significant independent predictor of all three of these outcome measures. Thus, renal survival among patients with systemic immunologic light chain amyloidosis who present with advanced CKD is strongly dependent upon the magnitude and speed with which the underlying hematologic disorder is suppressed by chemotherapy.

Increased fracture risk in plasma cell dyscrasias is associated with poorer overall survival.

Pathological fractures are a common complication of plasma cell dyscrasias (PCD) and are associated with significant morbidity. Routine use of bisphosphonates over the past decade has aimed to reduce the risk of fractures in patients with multiple myeloma, but despite this, fractures continue to represent a significant burden of disease. In this study we report the fracture rate of hospital in-patients with PCD in England. Data from the national registry Hospital Episode Statistics between 2001 and 2015 were used to determine fracture rate and its effect on overall survival. Fracture rates were 17·8 times higher than the general population in the first year after admission with PCD, and remained elevated for up to 10 years after first admission. The increased fracture risk preceded the first admission with PCD and, conversely, the incidence of PCD increased after admission with one or more fractures. Overall survival is improving with PCD, however poorer survival is found in patients with a preceding fracture (Hazard ratio 1·20). Despite widespread bisphosphonate use, fractures remain common in PCD, and are associated with poorer outcomes.

Patients with multiple myeloma have excellent long-term outcomes after recovery from dialysis-dependent acute kidney injury.

OBJECTIVES: The aim of this study was to report the long-term outcomes in patients with multiple myeloma (MM) who receive dialysis treatment for acute kidney injury (AKI) due to myeloma cast nephropathy and subsequently recover renal function. METHODS: Patients presenting with dialysis-dependent AKI secondary to myeloma cast nephropathy and subsequently recovering independent renal function between January 2005 and December 2012 were included in this study. Both renal and haematological parameters were collected at multiple time points as part of routine clinic practice. Factors associated with renal function and overall survival (OS) were determined. RESULTS: Twenty-four patients fulfilled the criteria for inclusion. Mean age was 62.1 years; 75% were male and 75% were of White ethnicity. The median OS was 64.1 months (95% confidence interval [CI] 34.8-93.3). Twenty-three (95.8%) patients remained dialysis-independent until death or end of follow-up; one patient required further haemodialysis treatment during the follow-up period. The independent determinant of worse OS was a known history of chronic kidney disease (CKD) at presentation. Shorter length of time on haemodialysis and higher percentage reduction in clonal serum FLC at day 21 from baseline predicted better excretory renal function (estimated glomerular filtration rate) at 6 months. CONCLUSION: In this series, the large majority of patients with MM and dialysis-dependent AKI secondary to myeloma cast nephropathy who recovered independent renal function had no requirement for further dialysis. Survival following recovery of renal function is good, and early variables are independently associated with survival and future renal function.

CMR-based differentiation of AL and ATTR cardiac amyloidosis.

OBJECTIVES: This study was devised to describe the different cardiac magnetic resonance (CMR) appearances in light chain amyloid (AL) and transthyretin-related amyloidosis (ATTR). BACKGROUND: CMR is increasingly used to investigate patients with suspected amyloidosis. Global subendocardial late gadolinium enhancement (LGE) has been reported as typical of AL amyloidosis, whereas different patterns have been noted in ATTR amyloidosis. METHODS: We performed de novo analyses on original DICOM magnetic resonance imaging in 46 patients with cardiac AL amyloidosis and 51 patients with ATTR type who had been referred to a specialist amyloidosis center between 2007 and 2012 after CMR. Histological examination was performed in all cases, with immunohistochemistry, to confirm systemic amyloidosis. RESULTS: Patients' median age was 68 ± 10 years, and 74% were male. Left ventricular mass was markedly increased in ATTR amyloidosis (228 g [202 to 267 g]) compared with AL type (167 g [137 to 191 g]) (p < 0.001). LGE was detected in all but 1 cardiac amyloidosis patient (AL type) and was substantially more extensive in ATTR compared with AL amyloidosis. Ninety percent of ATTR patients demonstrated transmural LGE compared with 37% of AL patients (p < 0.001). Right ventricular LGE was apparent in all ATTR patients but in only 33 AL patients (72%) (p < 0.001). Despite these findings, survival was significantly better in cardiac ATTR amyloidosis compared with AL type. We derived an LGE scoring system (Query Amyloid Late Enhancement) that independently differentiated ATTR from AL amyloidosis and, when incorporated into a logistic regression model with age and wall thickness, detected ATTR type with 87% sensitivity and 96% specificity. CONCLUSIONS: Transmural patterns of LGE distinguished ATTR from AL cardiac amyloidosis with high accuracy in this real-world analysis of CMR. Precise diagnosis of cardiac amyloidosis is crucial given the role of chemotherapy in AL type and with novel therapies for ATTR type currently in development.