# CHA2DS2-VA calculator CHA2DS2-VA Status: LIVE Price: $0.005 USDC `GET /api/calc/cha2ds2_va` HTML: https://magentlab.com/docs/cha2ds2-va Markdown: https://magentlab.com/docs/cha2ds2-va.md Not a medical device. Not a diagnosis, dose, or listing recommendation. ## What it computes Compute the ESC 2024 CHA2DS2-VA stroke-risk score from age and discrete clinical flags, without a sex category. ## When to use When an agent needs the 2024 ESC CHA2DS2-VA total (VASc without sex) and must not invent points from a chart narrative. ## When not to use - Not a medical device and not an anticoagulation order or treatment recommendation. - Not CHA2DS2-VASc. This tool drops the sex category (max 8, not 9) per ESC 2024. - Flags are caller-supplied booleans. magent does not infer CHF, stroke, or vascular disease from text. - Does not report annual stroke percentages. OAC none / consider / recommended follows ESC 2024 score bands only. ## Formula ``` CHA2DS2-VA = CHF 1 + HTN 1 + Age≥75 2 (or 65-74 1) + diabetes 1 + stroke/TIA 2 + vascular 1; no sex; max 8; OAC none (0) consider (1) recommended (≥2) (ESC 2024) ``` ## Citation [2024 ESC Guidelines for the management of atrial fibrillation developed in collaboration with the European Association for Cardio-Thoracic Surgery (EACTS)](https://doi.org/10.1093/eurheartj/ehae176) Van Gelder IC, Rienstra M, Bunting KV, et al. Eur Heart J. 2024;45(36):3314-3414 DOI: [10.1093/eurheartj/ehae176](https://doi.org/10.1093/eurheartj/ehae176) ## Worked example ### Age 78, all flags false Given: `age=78, chf=false, diabetes=false, hypertension=false, stroke_tia=false, vascular_disease=false` 1. Age ≥75 → 2; CHF, hypertension, diabetes, stroke/TIA, and vascular disease false → 0 2. Score = 2 (max 8); OAC recommended ## Also searched as - CHA2DS2-VA - CHA2DS2VA - ESC 2024 AF score - CHA2DS2-VA without sex - Van Gelder AF score - AF stroke score VA ## Parameters - `age` (integer, required): Age in years (18-120). ≥75 scores 2; 65-74 scores 1. - `chf` (boolean, required): Congestive heart failure or LV dysfunction. true or false. - `hypertension` (boolean, required): Hypertension history. true or false. - `diabetes` (boolean, required): Diabetes mellitus. true or false. - `stroke_tia` (boolean, required): Prior stroke, TIA, or arterial thromboembolism. true or false (2 points). - `vascular_disease` (boolean, required): Prior MI, peripheral artery disease, or aortic plaque. true or false. ## Bulk (POST) POST the same path with a JSON items array. The first item is the GET unit; each additional item is $0.002. Invalid items return HTTP 400 before settlement. Method: `POST /api/calc/cha2ds2_va` Max items: 25 Price: unit_amount + extra_item_amount * (n - 1) (unit 5000 atomic, extra 2000 atomic) Status: PREVIEW - 1 to 25 items. Each item uses the same keys as the GET query parameters. - POST of 1 item costs the same as GET. Lists longer than 25: chunk into multiple POSTs. Extra items still execute; do not pad dummy rows. - The first invalid item fails the whole request (index in the 400 JSON). You are not charged. - HTTP 200 is {count, path, items}. Each items[i] is the GET 200 body for that row. - Catalog misses (empty matches, found=false) stay paid 200s inside that slot. - x402 resource URL is this path plus n and body_sha256. Browsers that prefer text/html get the same paywall as GET; Pay retries POST with the same items. Example request: ```json { "items": [ { "age": "78", "chf": "false", "diabetes": "false", "hypertension": "false", "stroke_tia": "false", "vascular_disease": "false" }, { "age": "78", "chf": "false", "diabetes": "false", "hypertension": "false", "stroke_tia": "false", "vascular_disease": "false" } ] } ``` Human paywall (two-item fixture): https://api.magentlab.com/paywall/bulk/cha2ds2-va Example 200: ```json { "count": 2, "path": "/api/calc/cha2ds2_va", "items": [ { "components": [ { "factor": "congestive_heart_failure", "points": 0, "present": false }, { "factor": "hypertension", "points": 0, "present": false }, { "value": 78, "factor": "age", "points": 2, "present": true }, { "factor": "diabetes", "points": 0, "present": false }, { "factor": "stroke_tia_thromboembolism", "points": 0, "present": false }, { "factor": "vascular_disease", "points": 0, "present": false } ], "category": "recommended", "disclaimer": "Not a medical device. Deterministic published-formula or published-code output for autonomous agents. A licensed clinician remains responsible for patient care and billing submissions.", "citation": { "authors": "Van Gelder IC, Rienstra M, Bunting KV, et al.", "doi": "10.1093/eurheartj/ehae176", "id": "van-gelder-2024", "pmid": "39210723", "source": "Eur Heart J. 2024;45(36):3314-3414", "title": "2024 ESC Guidelines for the management of atrial fibrillation developed in collaboration with the European Association for Cardio-Thoracic Surgery (EACTS)" }, "formula": "cha2ds2_va", "formula_expression": "CHA2DS2-VA = CHF 1 + HTN 1 + Age≥75 2 (or 65-74 1) + diabetes 1 + stroke/TIA 2 + vascular 1; no sex; max 8; OAC none (0) consider (1) recommended (≥2) (ESC 2024)", "max_score": 8, "score": 2, "age_years": 78, "oac": "recommended" }, { "components": [ { "factor": "congestive_heart_failure", "points": 0, "present": false }, { "factor": "hypertension", "points": 0, "present": false }, { "value": 78, "factor": "age", "points": 2, "present": true }, { "factor": "diabetes", "points": 0, "present": false }, { "factor": "stroke_tia_thromboembolism", "points": 0, "present": false }, { "factor": "vascular_disease", "points": 0, "present": false } ], "category": "recommended", "disclaimer": "Not a medical device. Deterministic published-formula or published-code output for autonomous agents. A licensed clinician remains responsible for patient care and billing submissions.", "citation": { "authors": "Van Gelder IC, Rienstra M, Bunting KV, et al.", "doi": "10.1093/eurheartj/ehae176", "id": "van-gelder-2024", "pmid": "39210723", "source": "Eur Heart J. 2024;45(36):3314-3414", "title": "2024 ESC Guidelines for the management of atrial fibrillation developed in collaboration with the European Association for Cardio-Thoracic Surgery (EACTS)" }, "formula": "cha2ds2_va", "formula_expression": "CHA2DS2-VA = CHF 1 + HTN 1 + Age≥75 2 (or 65-74 1) + diabetes 1 + stroke/TIA 2 + vascular 1; no sex; max 8; OAC none (0) consider (1) recommended (≥2) (ESC 2024)", "max_score": 8, "score": 2, "age_years": 78, "oac": "recommended" } ] } ``` ## Response fields - `formula` (string): cha2ds2_va - `formula_expression` (string): Exact expression used - `score` (integer): Total points 0-8 - `max_score` (integer): Always 8 - `oac` (string): ESC 2024 oral-anticoagulation band: none (score 0), consider (score 1), or recommended (score ≥2). Not an order. - `category` (string): Same ESC 2024 band as oac: none, consider, or recommended. Not an order. - `age_years` (integer): Age used for A2/A scoring - `components` (array): Per-factor points - `citation` (object): ESC 2024 Eur Heart J citation - `disclaimer` (string): Not-a-device notice ## Example JSON Frozen fixture. Not a live lookup. ```json { "components": [ { "factor": "congestive_heart_failure", "points": 0, "present": false }, { "factor": "hypertension", "points": 0, "present": false }, { "value": 78, "factor": "age", "points": 2, "present": true }, { "factor": "diabetes", "points": 0, "present": false }, { "factor": "stroke_tia_thromboembolism", "points": 0, "present": false }, { "factor": "vascular_disease", "points": 0, "present": false } ], "category": "recommended", "disclaimer": "Not a medical device. Deterministic published-formula or published-code output for autonomous agents. A licensed clinician remains responsible for patient care and billing submissions.", "citation": { "authors": "Van Gelder IC, Rienstra M, Bunting KV, et al.", "doi": "10.1093/eurheartj/ehae176", "id": "van-gelder-2024", "pmid": "39210723", "source": "Eur Heart J. 2024;45(36):3314-3414", "title": "2024 ESC Guidelines for the management of atrial fibrillation developed in collaboration with the European Association for Cardio-Thoracic Surgery (EACTS)" }, "formula": "cha2ds2_va", "formula_expression": "CHA2DS2-VA = CHF 1 + HTN 1 + Age≥75 2 (or 65-74 1) + diabetes 1 + stroke/TIA 2 + vascular 1; no sex; max 8; OAC none (0) consider (1) recommended (≥2) (ESC 2024)", "max_score": 8, "score": 2, "age_years": 78, "oac": "recommended" } ``` ## Errors - HTTP 400 `invalid_age`: age must be an integer from 18 to 120 Returned before settlement; you are not charged. - HTTP 400 `invalid_flag`: boolean clinical flags must be true or false Returned before settlement; you are not charged. - HTTP 400 `invalid_items`: POST body must be a JSON object with only an items array Returned before settlement; you are not charged. - HTTP 400 `invalid_item_count`: items must be an array of 1 to 25 objects Returned before settlement; you are not charged. - HTTP 400 `invalid_item`: each items entry must be a JSON object Returned before settlement; you are not charged. Shared HTTP 402 and 503: https://magentlab.com/docs/payments ## Related tools - [CHA2DS2-VASc](https://magentlab.com/docs/cha2ds2-vasc) — Compute the CHA2DS2-VASc stroke-risk score from discrete clinical flags. - [CHADS2](https://magentlab.com/docs/chads2) — Compute the CHADS2 stroke-risk score from discrete clinical flags. - [HAS-BLED](https://magentlab.com/docs/has-bled) — Compute the HAS-BLED bleeding-risk score from discrete clinical flags. - [ORBIT bleeding score](https://magentlab.com/docs/orbit) — Compute the O'Brien 2015 ORBIT bleeding score from age and caller-assigned anemia, bleeding history, insufficient kidney, and antiplatelet flags. ## Payment Unpaid requests return HTTP 402 even if query parameters or POST items are missing or invalid, so CDP and agents can index the path. After a PAYMENT-SIGNATURE, invalid params return HTTP 400 JSON before settlement. magent does not charge. Fix the params, then request a new 402 quote for that complete URL. Catalog misses (empty matches, found=false) are valid paid 200s. - GET the tool with Accept: application/json (do not send Accept: text/html unless you want the human paywall). - HTTP 402 means you have not paid. Decode the base64 PAYMENT-REQUIRED header. HTTP 503 is not a new quote. - Sign accepts[0] (exact, EIP-3009) with validBefore = now + maxTimeoutSeconds (600 seconds), or accepts[1] (batch-settlement deposit/voucher) on product GET. Ping and POST {items} stay exact. Magent retries transient facilitator 429/5xx before answering. - Retry the same URL with PAYMENT-SIGNATURE (base64 JSON of accepted and payload). Magent attaches canonical extensions.bazaar on CDP verify/settle; echoing 402 bazaar is optional. - Success is HTTP 200 JSON plus PAYMENT-RESPONSE. exact settles before the tool. batch-settlement verifies (and deposit-settles) before the tool and commits the charge after HTTP 2xx. HTTP 503: retry the same PAYMENT-SIGNATURE. Mint a new exact nonce only after a new HTTP 402. - offered `exact` on eip155:8453: Fixed-price USDC on Base. The buyer authorizes the advertised amount (EIP-3009). magent settles before the tool runs (paymentFlow upfront). extra.assetTransferMethod=eip3009 extra.paymentFlow=upfront. - offered `batch-settlement` on eip155:8453: Payment-channel vouchers claimed later in batches. Exact stays accepts[0]. Same-path POST {items} is still exact. extra.assetTransferMethod=eip3009 extra.paymentFlow=authorization. - not offered `upto`: Not offered. Usage-based: buyer authorizes a ceiling, seller settles the actual amount after work. Reserved for a future metered tool. Not for current calculators or code search. Same-path POST {items} is still scheme exact: one EIP-3009 authorization for GET unit plus $0.002 per extra item. That is not x402 batch-settlement (payment channels / vouchers). Shared HTTP 402 and 503 table: https://magentlab.com/docs/payments Stdio MCP (one process per host): https://magentlab.com/docs/mcp ## Guarantees - HTTP 402 is unpaid, including a missing query. After PAYMENT-SIGNATURE, invalid parameters return HTTP 400 before settlement. You are not charged. HTTP 402 never includes the tool JSON. - exact: settlement finishes before the tool (paymentFlow upfront). batch-settlement: verify/deposit before the tool; chargedCumulativeAmount commits after HTTP 2xx. Uncertain or failed settlement fails closed (HTTP 503). Retry the same PAYMENT-SIGNATURE. - HTTP 402 is unpaid only. Do not sign a second authorization because of a 503. - Execution is timeout-bounded and concurrency-capped. - Calculator inputs are stored encrypted for allowlisted operators (Magent Console). They are not in public logs, SSH lookups, catalog, or rollups. Request logs store path without query.