Clinical Characteristics and Outcome of Patients with Wild-Type Transthyretin and AL Cardiac Amyloidosis Confirmed By Mass Spectrometry
Bibliographic record
Abstract
Abstract INTRODUCTION: Cardiac involvement is common in both wild-type transthyretin (wATTR) and AL amyloidosis and these entities can have overlapping clinical features (Banypersad et al, JAHA 2012). Accurate diagnosis is vital given differences in spectrum of disease, management, and prognosis. We examined the presenting clinical features and survival outcome of patients diagnosed with cardiac wATTR and AL amyloidosis confirmed by mass spectrometry. MATERIALS & METHODS: Patients diagnosed between January 2014 and September 2017 with biopsy proven wATTR or AL amyloidosis and cardiac involvement by consensus criteria (Gertz et al, Amyloid 2010) were included. Mass spectrometry testing was performed at the Mayo Clinic Laboratories to confirm amyloid subtype in all cases. Patient records were retrospectively reviewed to identify clinical characteristics as well as details regarding treatment and survival. RESULTS: Forty-three patients were identified (wATTR n=27, AL n=16) with site of biopsy: 41 cardiac (95%); 1 gastric (2%); 1 skin (2%). Two (13%) patients with AL amyloid had coexisting multiple myeloma. Thirty-five (81%) patients were male, with a strong male predominance in wATTR patients (100% vs 50% for AL patients, p=<0.01). Median age at diagnosis was 73 years (range 45-86), with a trend towards older age in wATTR patients (median 75 vs 62 years for AL patients, p=0.09). No difference was seen in presenting NYHA class or levels of troponin and ntProBNP between amyloid subtypes. BNP trended towards higher values in AL patients (median 514 vs 249 ng/L for wATTR, p=0.09). wATTR amyloid patients had lower median presenting left ventricular ejection fraction (43 vs 53%, p=0.05). Two (7%) patients with wATTR amyloid had an M-protein on SPEP compared to 7 (44%) with AL amyloid. Only 2 patients with AL amyloid had M-protein greater than 5 g/L while both wATTR patients had less than 5 g/L. In those with serum free light chain testing available (wATTR n=24, AL n=16), median lambda light chain level was higher in AL patients (176.0 vs 16.9 mg/L for wtATTR, p=<0.01). No difference was seen in kappa light chains (16.5 vs 23.8 mg/L for wATTR, p=0.60), though the only patient with kappa AL amyloid had kappa light chains significantly elevated at 1640 mg/L. The kappa/lambda ratio was abnormal in 15% of wATTR patients (all kappa predominant) compared to 100% in AL amyloid patients (94% lambda predominant) (p=<0.01). The median difference between involved and uninvolved light chain (dFLC) was 22 mg/L for wtATTR patients compared to 249 mg/L for AL patients. In patients with bone marrow biopsy results available (AL n=15, wATTR n=7), bone marrow plasma cell percentage was higher in patients with AL amyloid (median 7% vs 2%, p=0.01). No monoclonal plasma cells were seen on bone marrow in wATTR patients by immunophenotype. Treatment for patients with AL amyloid was: bortezomib, cyclophosphamide, and dexamethasone (VCD) in 11 (69%); VCD followed by melphalan 200 mg/m2 autologous transplantation in 1 (6%); melphalan/dexamethasone in 1 (6%); no treatment in 2 (13%); unknown in 1 (6%). In evaluable patients, hematologic response rate was 54% (complete response n=4, very good partial response n=2, partial response n=1, no response n=6). With a median follow-up of 1.8 years for surviving patients, 1 year overall survival (OS) was 76% for the entire cohort. Patients with AL amyloidosis had significantly poorer 1 year OS (41% vs 92% for wATTR patients, p=<0.01). Patients with NYHA class 3-4 had significantly worse 1 year OS (54% vs 96% for those 1-2, p=<0.01), and this held true for both AL and wATTR patients. In AL patients, revised Mayo stage (Kumar et al, JCO 2012) of III-IV predicted for poor 1 year OS (19% vs 75% for stages I-II, p=0.03), as did not achieving complete response to primary treatment (1 year OS 33% vs 67% for CR patients, p=0.06). DISCUSSION & CONCLUSIONS: Male sex, older age, and lower LVEF were more common in patients with wATTR compared to AL amyloidosis. Higher levels of BNP, larger dFLC with lambda predilection, and higher bone marrow plasma cell percentage were more common in AL amyloid patients. Overall survival was significantly worse for patients with AL amyloidosis, particularly those with high NHYA class, advanced revised Mayo stage, and suboptimal response to primary therapy. These results highlight the importance of accurate amyloid sub-typing in patients with suspected cardiac amyloidosis. Disclosures No relevant conflicts of interest to declare.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.002 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.001 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.002 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".