FDA 510(k) Search - By Innolitics (SaMD and AI Experts)

The Hypertension Notification Feature (HTNF) is a software-only mobile medical application that analyzes photoplethysmography (PPG) data opportunistically collected by Apple Watch to identify patterns that are suggestive of hypertension and provides a notification to the user.

The feature is intended for over-the-counter (OTC) use by adults age 22 and over who have not been previously diagnosed with hypertension. It is not intended to replace traditional methods of diagnosis, to monitor hypertension treatment effect, or to be used as a method of blood pressure surveillance. It is not intended for use during pregnancy. The absence of a notification does not indicate the absence of hypertension.

Device Description

The Hypertension Notification Feature (HTNF) is an over-the-counter mobile medical application that is intended to analyze data collected from the PPG sensor of the Apple Watch (a general purpose computing platform), over multiple days to surface a notification to users who may have hypertension. The feature is intended for adults who have not been previously diagnosed with hypertension. The feature is not intended for use during pregnancy. The feature is not intended to replace traditional methods of diagnosis, to monitor hypertension treatment effect, or to be used as a method of blood pressure surveillance.

Absence of a notification does not indicate the absence of hypertension. HTNF cannot identify every instance of hypertension. In addition, HTNF will not surface a notification if insufficient data is collected.

HTNF comprises the following features:
• A software feature on the Apple Watch ("Software Feature on Watch"), and
• A pair of software features on the iOS device ("Software Feature on iPhone" and "Software Feature on iPad")

On the Apple Watch, HTNF uses PPG data and qualification information from the watch platform. The Software Feature on watch incorporates a machine-learning model that gives each qualified PPG signal a score associated with risk of hypertension.

On the iPhone, HTNF incorporates an algorithm that aggregates qualified hypertension risk scores and identifies patterns suggestive of hypertension. If hypertension patterns are identified, the feature surfaces a notification to users that they may have hypertension. The feature includes a user interface (UI) framework to enable user on-boarding and display educational materials and hypertension notification history in the Hypertension Notification room in the Health app.

On the iPad, HTNF provides a data viewing framework to display hypertension notification history in the Hypertension Notification room in Health app.

AI/ML Overview

Here's a summary of the acceptance criteria and the study that proves the Apple Hypertension Notification Feature (HTNF) meets them, based on the provided FDA 510(k) clearance letter:

Apple Hypertension Notification Feature (HTNF) - Acceptance Criteria and Study Summary

1. Table of Acceptance Criteria and Reported Device Performance

Metric	Acceptance Criteria (Explicitly Stated Goals)	Reported Device Performance (Clinical Validation)
Overall Sensitivity	"met all pre-determined primary endpoints" (implies a specific target was met, but the value itself is not given as the criteria here)	41.2% (95% CI [37.2, 45.3])
Overall Specificity	"met all pre-determined primary endpoints" (implies a specific target was met, but the value itself is not given as the criteria here)	92.3% (95% CI [90.6, 93.7])
Hypertension Definition	Average systolic blood pressure ≥ 130 mmHg OR diastolic blood pressure ≥ 80 mmHg (America Heart Association guidelines)	Used as the ground truth for hypertension status
Sensitivity for Stage 2 HTN	Not explicitly stated as an acceptance criterion/primary endpoint, but analyzed	53.7% (95% CI [47.7, 59.7])
Specificity for Normotensive	Not explicitly stated as an acceptance criterion/primary endpoint, but analyzed	95.3% (95% CI [93.7, 96.5])
Long-term Specificity (Non-Hypertensives)	Not explicitly stated as an acceptance criterion/primary endpoint, but observed	86.4% (95% CI [80.2%, 92.5%]) after 2 years
Long-term Specificity (Normotensives)	Not explicitly stated as an acceptance criterion/primary endpoint, but observed	92.5% (95% CI [86.8%, 98.3%]) after 2 years

Note: The document states that the feature "met all pre-determined primary endpoints" for overall sensitivity and specificity, but the specific numerical targets for these endpoints are not directly listed as "acceptance criteria" in the provided text. The reported performance values are the results from the clinical study that met these implicit criteria.

2. Sample Size Used for the Test Set and Data Provenance

Test Set Sample Size:
- Clinical Validation Study: 2,229 enrolled subjects, with 1,863 subjects providing at least 15 days of usable data for the primary endpoint analysis.
- Longitudinal Performance Evaluation: 187 non-hypertensive subjects.
Data Provenance: The document does not explicitly state the country of origin for the data. However, it indicates subjects were "enrolled from diverse demographic groups" and "representative of the intended use population." The study described is a prospective clinical validation study where subjects wore an Apple Watch and measured blood pressure.

3. Number of Experts Used to Establish the Ground Truth for the Test Set and Qualifications

The document does not specify the use of "experts" to establish the ground truth for the test set.

Ground Truth Method: Hypertension status was defined based on objective measurements from an FDA-cleared home blood pressure monitor. Specifically, "Hypertension is established as average systolic blood pressure ≥ 130 mmHg or diastolic blood pressure ≥ 80 mmHg by America Heart Association." Therefore, expert consensus was not the primary method for ground truth determination in the principal clinical study.

4. Adjudication Method for the Test Set

Not applicable, as the ground truth was based on objective blood pressure monitor readings against established guidelines, not expert review requiring adjudication.

5. If a Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study Was Done, and Effect Size

No, an MRMC comparative effectiveness study was not conducted. The HTNF is an "algorithm only" device designed to provide notifications to lay users, not an assistive tool for human readers in a diagnostic setting.

6. If a Standalone (i.e., algorithm only without human-in-the-loop performance) Was Done

Yes, the primary clinical validation study assessed the standalone performance of the HTNF algorithm. The device "analyzes photoplethysmography (PPG) data... to identify patterns that are suggestive of hypertension and provides a notification to the user," without human intervention in the interpretation of the PPG data for notification generation.

7. The Type of Ground Truth Used

The ground truth used for the clinical validation study was objective outcome data (blood pressure measurements). Specifically, "Hypertension is established as average systolic blood pressure ≥ 130 mmHg or diastolic blood pressure ≥ 80 mmHg by America Heart Association" using an FDA-cleared home blood pressure monitor as the reference.

8. The Sample Size for the Training Set

The document describes the algorithm development dataset as follows:

Self-supervised learning for deep-learning (DL) model: "large-scale unlabeled data... included Apple Watch sensor data collected over 86,000 participants."
Linear model training for classification: "included Apple Watch sensor data and home blood pressure reference measurements collected over 9,800 participants."

These datasets were pooled and split into Training, Train Dev, Test Dev, and Test sets for model development.

9. How the Ground Truth for the Training Set Was Established

For the linear model that provides specific hypertension classifications (hypertensive vs. non-hypertensive), the ground truth for the training set was established using home blood pressure reference measurements. For the self-supervised deep learning model, it used "large-scale unlabeled data" where ground truth for hypertension status wasn't required for pre-training.

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K Number

K252527

Device Name

Surfacer Inside-Out Access Catheter System

Manufacturer

Merit Medical System Inc.

Date Cleared

2025-09-10

(30 days)

Product Code