Carroll, Antonia

Abstract In this systematic review, we aimed to assess the sensitivity of serum immunofixation (SIFE), urine immunofixation (UIFE), and serum free light chain (sFLC) in detecting plasma cell dyscrasia associated with light chain (AL) amyloidosis. We searched the literature using PubMed, Embase, and CENTRAL databases since inception through March 2024. We included studies reporting the diagnostic accuracy of immunofixation and/or sFLC in patients with AL amyloidosis. We used the GRADE (Grading of Recommendations, Assessment, Development, and Evaluation) approach to assess the certainty of the evidence and QUADAS-2 (Quality Assessment of Diagnostic Accuracy Studies-2) to assess the risk of bias. After deduplication, 29 237 records were screened, and 44 studies (n = 18 071) were included. For the meta-analysis, 28 studies reported sensitivity for SIFE (n = 3390), 24 studies for UIFE (n = 2830), 19 studies for SIFE and UIFE (n = 2819), 21 studies for sFLC ratio (n = 3678), 6 studies for SIFE and sFLC ratio (n = 372), 3 studies for UIFE and sFLC ratio (n = 242), and 10 studies for all 3 tests (n = 1430). Pooled sensitivities were as follows: SIFE, 0.68 (95% confidence interval [CI], 0.62-0.73); UIFE, 0.77 (95% CI, 0.72-0.81); SIFE and UIFE, 0.89 (95% CI, 0.84-0.93); and sFLC ratio, 0.82 (95% CI, 0.78-0.86). When SIFE, UIFE, and sFLC ratio were combined, the sensitivity reached 0.99 (95% CI, 0.96-1.00). The high sensitivity of combining SIFE, UIFE, and sFLC ratio supports their use as a reliable initial testing strategy to raise suspicion for AL amyloidosis and guide decisions regarding future diagnostic modalities.

Abstract Systemic amyloidosis is a rare, multisystem disorder that is often challenging to diagnose due to vague and nonspecific symptoms that frequently overlap with other disorders. By the time patients are diagnosed, irreversible organ impairment from amyloid deposition occurrs, contributing to substantial morbidity and mortality. Although developing the American Society of Hematology (ASH) guidelines on systemic amyloidosis, we identified a critical knowledge gap in the recognition of the clinical presentation of its most common subtypes. Therefore, we conducted a scoping review of 117 studies following PRISMA-ScR (Preferred Reporting Items for Systematic reviews and Meta-Analyses extension for Scoping Reviews) guidelines to identify clinical “red flags” for light chain (AL) and transthyretin (ATTR; wild-type [ATTRwt] and hereditary [ATTRv]) amyloidosis. Studies were identified from the comprehensive systematic review through the ASH amyloidosis diagnosis guideline panel, data mining, and gray literature review. Data were extracted and synthesized by systems to characterize the earliest and most frequently overlooked clinical red flags for the different types of amyloidosis. Shortness of breath and fatigue, the earliest symptoms of AL amyloidosis, contrast with the carpal tunnel syndrome occurring years before ATTRwt cardiac amyloidosis is diagnosed. Weight loss, unexplained abdominal pain, and early satiety were overlooked red flags for AL amyloidosis, compared to the preceding arrhythmias often missed in evaluation for ATTRwt amyloidosis. Sensory loss was the predominant neuropathic presentation for AL amyloidosis compared to the painful length-dependent neuropathy of ATTRv amyloidosis. Awareness of the early symptoms and distinct patterns across subtypes can enhance cross-specialty awareness and support earlier diagnosis and intervention of AL and ATTR amyloidosis.

Background Light chain (AL) amyloidosis is a rare disease caused by the misfolding of immunoglobulin light chains produced by a plasma cell dyscrasia. Patients can present with involvement of many organs, including the heart, kidneys, liver, nerves, and other sites, resulting in a high symptom burden. Timely and accurate diagnosis is important to prevent organ failure and improve patient survival. Objective These evidence-based guidelines of the American Society of Hematology (ASH) are intended to support patients and clinicians in the timely and effective diagnosis of AL amyloidosis. Methods ASH formed a multidisciplinary guideline panel that included 22 individuals representing various medical specialties (academic and community hematology, nephrology, neurology, cardiology, internal medicine, and pathology) as well as 1 patient representative. The group was balanced to minimize potential bias from conflicts of interest. The University of Kansas Medical Center supported the guideline development process, including updating or performing systematic evidence reviews (up to 6 March 2023). The panel prioritized clinical questions and outcomes according to their importance for clinicians and patients. The panel used the Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach, including GRADE evidence-to-decision frameworks, to assess evidence and make recommendations, which were subject to public comment. Results The panel agreed on 12 recommendations. Conclusions The use of serum immunofixation, urine immunofixation, and serum free light chains enhances the clinical suspicion of AL amyloidosis. The diagnosis of AL amyloidosis can be made effectively through surrogate biopsies, which require both a bone marrow biopsy and fat-pad sampling; however, target organ biopsies may be favored in certain clinical situations.

Introduction: For cardiac transthyretin (ATTR) amyloidosis, bone scintigraphy has emerged as a noninvasive diagnostic tool. The use of different tracers, namely Pyrophosphate (PYP), 3,3-diphosphono-1,2-propanodicarboxylic acid (DPD), HydroxymethyleneDiphosphonate (HMDP), allow for the detection of amyloid deposits in the heart. The aim of this systematic review is to evaluate the diagnostic test accuracy of bone scintigraphy in ATTR and light chain (AL) amyloidosis. Methods: As part of the ASH AL Amyloidosis Diagnostic Guideline, we performed systematic reviews for 7 prioritized PICO questions related to the screening, diagnosis and organ involvement evaluation of AL amyloidosis. Electronic searches were conducted on PubMed, Embase, and the Cochrane Central Register of Controlled Trials from inception till January 2024. Two reviewers independently and in duplicate performed title and abstract screening and full text article screening on LASER AI, with conflicts resolved by a third reviewer. Studies were eligible if they included patients that performed both a bone scintigraphy scan and an endomyocardial biopsy for suspicion of ATTR amyloidosis. Test positivity for the visual score was defined to be ≥2, for the heart over contralateral (H/CL) ratio it was > 1.5 at one hour and >1.3 at 3 hours. Diagnostic test accuracy measures of interest were sensitivity, specificity, positive and negative predictive value. Statistical analysis was performed on STATA 18.0. Grading of Recommendations Assessment, Development and Evaluation (GRADE) was used to assess the certainty of evidence. Results: After deduplication, we retrieved 29,237 studies from electronic databases. 12 studies with 1127 patients reported on visual score in patients suspected to have ATTR amyloidosis. The pooled sensitivity for visual score was 96% (95% CI 92.0-98.0) while specificity was 90% (95% CI 84.0-95.0) (Certainty of evidence (COE): Moderate ⨁⨁⨁◯). 3 studies reported on ATTR visual score in combination with evaluating for monoclonal gammopathy, the pooled sensitivity was decreased to 93% (95% CI 65-99) and while specificity increased to 99% (95% CI 80-100) (COE: Moderate ⨁⨁⨁◯). H/CL was evaluated in 5 studies with 189 patients; pooled sensitivity was 97% (95% CI 89.0-99.0) and specificity was 88% (95% CI 64-97) (COE: Low ⨁⨁◯◯). We also performed subgroup analyses for the diagnostic test accuracy of visual score for the different tracers (PYP, DPD, HMDP) in patients suspected to have ATTR amyloidosis. DPD was found to have the highest sensitivity which was found to be 97% (95% CI 91.0-99.0) and a specificity of 95 (95% CI 86.0-98.0) (4 studies, n = 297 COE: Moderate ⨁⨁⨁◯). The sensitivity and specificity for PYP was 95% (95% CI 87.0-98.0) and 90% (95% CI 79.0-96.0) (7 studies, n = 377 COE: Moderate ⨁⨁⨁◯). 1 study reported on HMDP with a sensitivity and specificity of 79% (95% CI 49.0-95.0) and 100% (95% CI 59.0-100.0) (COE: Low ⨁⨁◯◯). Conclusion: Bone scintigraphy has a high sensitivity and specificity for the diagnosis of ATTR amyloidosis, particularly in patients without a monoclonal gammopathy.

Introduction: Although endomyocardial biopsy is the gold standard, echocardiography, and Cardiac Magnetic Resonance (CMR) play a pivotal role in the diagnosis of cardiac amyloidosis. In this systematic review, we aim to estimate the diagnostic test accuracy (DTA) of CMR and echocardiography for cardiac amyloidosis. Methods: As part of the American Society of Hematology guidelines on the diagnosis of Amyloidosis, we searched PubMed, Embase, and the Cochrane Central Register of Controlled Trials from inception till January 2024 for relevant studies. Two reviewers independently performed title and abstract screening and full-text article screening on LASER Al and extracted relevant data using a piloted Excel sheet. We performed statistical pooling using Stata 18.0 software. We evaluated risk of bias using Quality Assessment of Diagnostic Accuracy Studies-2 (QUADAS-2) and used the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) approach to assess the certainty of the evidence. We report diagnostic test accuracy as sensitivity (95% confidence interval) and specificity (95% confidence interval). Results: After screening 29,237, we included 9 studies assessing DTA of late gadolinium enhancement (LGE) on cardiac magnetic resonance (CMR) using an endomyocardial biopsy (EMB) as a reference test in patients with amyloidosis (light chain and ATTR). The majority of studies didn't report on the type of amyloidosis where only 2 out of 9 were in patients with light chain amyloidosis. The pooled estimates for sensitivity and specificity of LGE are 0.95 (0.88. 0.98), and 0.81 (0.60, 0.92), respectively. We did a sensitivity analysis and included only LGE suggestive for amyloidosis which didn't change sensitivity but led to an increase in specificity for amyloidosis to 0.87 (0.76, 0.94), respectively. The pooled estimates were based on moderate certainty in the evidence. For 2-dimensional echocardiography, we addressed DTA for different echocardiographic findings and we did not limit the reference to EMB. A panel of experts judged whether the reference was acceptable or not. Acceptable reference was EMB alone or a combination of extracardiac biopsy plus cardiac imaging (CMR or echocardiography) with or without positive cardiac biomarkers (troponin or BNP or NT-proBNP). Six studies (n=2063) addressed interventricular septum thickness (IVS), sensitivity was 0.77 (0.69, 0.84) and specificity was 0.71 (0.60, 0.81). 4 out of 6 studies used 12 mm as a cutoff while the other 2 studies used 13 mm as a cutoff. Only 2 studies (n=1667) assessed the DTA of posterior wall thickness (PWT), with sensitivity ranging from 0.76 to 1.00, and specificity ranging from 0.84 to 0.89. Six studies (n=438) addressed diastolic dysfunction (grade 2,3), with a sensitivity of 0.71 (0.40, 0.90), and specificity of 0.75 (0.64, 0.84). 7 studies (n=472) reported DTA of only diastolic dysfunction grade 3. When compared to diastolic dysfunction (grade 2,3, sensitivity decreases to 0.42 (0 28. 0.58) and specificity increases to 0.89 (0.83. 0.94). For E/A ratio, only 2 studies (n=127) were included. Sensitivity ranged from 0.45 to 0.65, and specificity ranged from 0.85 to 0.98. Four studies (n=1596) yielded a sensitivity of 0.86 (0.65, 0.95) and specificity of 0.76 (0.55, 0.89) of left ventricular global longitudinal strain (GLS). All except one used -17% as a cutoff for GLS. For apical sparing on GLS, pooled estimates from 8 studies (n=2253) led to a sensitivity of 0.72 (0.64, 0.78) and specificity of 0.78 (0.64, 0.88). There was a variation of cutoff across studies. The certainty of evidence for echocardiographic findings was low to moderate. Conclusion: CMR is a more accurate test with better performance compared to echocardiography.

Introduction: Light-chain (AL) amyloidosis is caused by the secretion of immunoglobulin light chains by monoclonal plasma cells. The increase in the levels of these monoclonal proteins may proceed the development of any clinical symptoms, and their identification in the serum and urine remains an integral part of establishing a diagnosis of AL amyloidosis. This systematic review aims to evaluate the diagnostic test accuracy of serum immunofixation (SIFE), urine immunofixation (UIFE), and free light chain (FLC) ratio for the diagnosis of AL amyloidosis. Methods: As part of the ASH AL Amyloidosis Diagnostic Guideline, we performed systematic reviews for 7 prioritized PICO questions related to the screening, diagnosis and organ involvement evaluation of AL amyloidosis. Electronic searches were conducted on PubMed, Embase, and the Cochrane Central Register of Controlled Trials from inception till January 2024. Two reviewers independently and in duplicate performed title and abstract screening and full text article screening on LASER AI, with conflicts resolved by a third reviewer. Eligible studies were those that included patients who performed one of the three tests (SIFE, UIFE, and κ/λ FLC) and had their AL amyloidosis diagnosis confirmed via a biopsy. Diagnostic test accuracy measures of interest were sensitivity, specificity, positive and negative predictive value. Statistical analysis was performed on OpenMeta[Analyst]. Grading of Recommendations Assessment, Development and Evaluation (GRADE) was used to assess the certainty of evidence. Results: After deduplication, we retrieved 29,237 studies from electronic databases. 31 studies with 3973 patients reported on the use of serum immunofixation (SIFE) with a pooled sensitivity of 72.4% (95% CI 68.1%-76.4%). 27 studies with 2855 patients reported on the use of urine immunofixation UIFE for the diagnosis of AL amyloidosis with a pooled sensitivity of 78.6% (95% CI 74.6%-82%). 29 studies with 5305 patients reported on the use of κ/λ FLC ratio amyloidosis with a pooled sensitivity of 79.9% (95% CI 73.7%-84.9%). 24 studies reported on the use of both SIFE and UIFE with a sample size of 3751 patients and a pooled sensitivity of 90% (95% CI 85.3%-93.3%). 3 studies reported on the use SIFE and κ/λ FLC ratio with 321 patients and a pooled sensitivity of 97.7% (95% CI 95.6%-99.9%). Finally, we identified 10 studies that performed SIFE,UIFE, and κ/λ FLC ratio concurrently with 1926 patients and a pooled sensitivity of 99% (95% CI 97%-99.7%) of all three tests and considering a result abnormal if any of the components had a positive result. We also identified 5 studies with 957 patients reporting on the concurrent use of SIFE, UIFE, and κ/λ FLC ratio for the diagnosis AL amyloidosis and differentiation of AL from ATTR amyloidosis in a population of patients with suspected cardiac amyloid involvement, the pooled sensitivity was found to be 99%(95% CI 99%-100%) and with a pooled specificity of 77%(95% CI 75%-80%). Certainty of evidence moderate for all outcomes. Conclusion: The combined use of SIFE, UIFE, and κ/λ FLC ratio has a high sensitivity for the diagnosis of AL amyloidosis, and the tests remain a valuable initial screening of AL amyloidosis and differentiation from ATTR amyloidosis.