SecProbe.io

March 5, 2025
John C.M. Farquhar
Chief Executive Officer
Heartflow, Inc.
331 E. Evelyn Avenue
Mountain View, CA 94041
Re:Heartflow, Inc.
Draft Registration Statement on Form S-1
Submitted February 6, 2025
CIK No. 0001464521
Dear John C.M. Farquhar:
            We have reviewed your draft registration statement and have the following comments.
            Please respond to this letter by providing the requested information and either
submitting an amended draft registration statement or publicly filing your registration
statement on EDGAR. If you do not believe a comment applies to your facts and
circumstances or do not believe an amendment is appropriate, please tell us why in your
response.
            After reviewing the information you provide in response to this letter and your
amended draft registration statement or filed registration statement, we may have additional
comments.
Draft Registration Statement on Form S-1 submitted February 6, 2025
Cover Page
1.We note your disclosure on page 62 that, after this offering, certain of your executive
officers, directors, owners of more than 5% of your capital stock, and their affiliates
will have the ability to influence you through their ownership position, including the
potential ability to determine all matters requiring stockholder approval. Please revise
your cover page to include disclosure describing the control of these shareholders and
affiliates.
Prospectus Summary, page 1
Here and throughout your registration statement where you provide disclosure
regarding the industry in which you operate, your competitors, and market statistics, 2.

March 5, 2025
Page 2
please provide support for your disclosures, including, as applicable, the basis for
management's opinions or beliefs. For example only, we note the following
statements:

•"We estimate that there were approximately 9.5 million non-invasive tests
(“NITs”) in the United States in 2023 for patients experiencing stable or acute
chest pain, which we refer to as symptomatic CAD patients;"
•Stress-based NITs are "inaccurate, a majority of the time, and often result in either
missed CAD diagnoses or unnecessary invasive procedures;" "approximately 20-
50% of patients who undergo stress-based NITs go home with false negative or
undetected CAD;" and "up to 55% of patients receive false positives;"
•"We estimate that as of December 31, 2023, there were approximately 2,700
hospitals and outpatient facilities in the United States that perform CCTA, and
this target account base has grown at a 10% CAGR from 2018 to 2023;" and
•"With the elevation of CCTA to a Class 1, Level A guideline recommendation by
the AHA and ACC guidelines in 2021, CCTA test volumes have grown at a 22%
CAGR from 2018 to 2023 while SPECT volumes have grown at a 2% CAGR
over the same time period."

Please make conforming changes throughout your filing, including to your description
of your business, competition, and the industry in which you operate.
Overview, page 1
3.We note your disclosure on page 2 that "Heartflow FFRCT Analysis calculates blood
flow and pinpoints functionally significant CAD at every point in the major coronary
arteries, guiding decisions on whether a patient requires invasive revascularization."
Please define "functionally significant."
4.We note your disclosure on page 3 that "[t]he CCTA + Heartflow FFRCT Analysis
pathway is supported by the American Heart Association (“AHA”) and American
College of Cardiology (“ACC”) guidelines, with CCTA identified as a Class 1, Level
A test and Heartflow FFRCT Analysis identified as a Class 2a, Level B test,"
"Heartflow FFRCT Analysis is reimbursed under a dedicated Category 1 Current
Procedural Terminology (“CPT”) code," and "A Category 1 CPT code was also
recently established for Heartflow Plaque Analysis, which will take effect in January
2026, and it is covered by all seven Medicare administrative contractor (“MACs”)."
Please revise your disclosure here or provide a cross reference to more detailed
disclosure in the filing to further explain the various classes, levels and reimbursement
categories pursuant to current clinical guidelines and reimbursement policies,
including those of the AHA and ACC. We also note your disclosure on page 103
that "CCTA now has guideline support from the European Society of Cardiology
Clinical Practice guidelines on Chronic Coronary Syndromes (1B), is included in the
National Institute for Health and Care Excellence (“NICE”) guidelines in the United
Kingdom, and in the Japanese Circulation Society (“JCS”) 2022 Guidelines in Japan."
Please revise to discuss the significance of receiving guideline support from each of
these institutions.

March 5, 2025
Page 3
5.We note your disclosure on page 22 that the Heartflow Platform relies on a CCTA
first being performed, and that companies performing CCTA could determine to
develop, partner with, or acquire and offer a product that competes with the Heartflow
Platform, or manufacture CT scanners that are no longer compatible with the
Heartflow Platform. Please revise your summary to discuss the Heartflow Platform's
reliance on third-party CCTAs and compatible CT scanners, including any risks or
limitations related to this reliance.
6.Please revise to disclose your accumulated deficit for the fiscal years ended December
31, 2024 and 2023.
Our symptomatic CAD market opportunity, page 5
We note that you discuss estimates for your market opportunity in the United States
throughout your filing. Please address the following issues related to your market
opportunity estimates:

•You disclose on page 2 that you estimate your current market opportunity in the
United States is approximately $5 billion, and that you believe "Heartflow FFRCT
Analysis is applicable to approximately 33% of NIT patients annually and the
majority of patients experiencing acute chest pain, which represents 3.1 million
patients and an estimated market opportunity of approximately $3.3 billion in the
United States." Please provide support for your statements regarding the number
of patients "experiencing acute chest pain," including sources for this information
and clarify how you arrived at a market opportunity of $3.3 billion based on this
estimate. Include a discussion of the material assumptions underlying your
estimates, including price per product, reimbursement rates, etc.
•As a related matter, we note your disclosure on page 5 that "Heartflow FFRCT
Analysis is reimbursed for use on any CCTA showing 40% to 90% stenosis,
which [you] estimate to be approximately 33% of all CCTAs annually," and that
you "believe that CCTA + Heartflow FFRCT Analysis therefore is applicable to
33% of the NIT market and a majority of patients experiencing acute chest pain,
which represents 3.1 million patients and an estimated market opportunity of
approximately $3.3 billion in the United States." Please provide the data, sources,
and assumptions underlying your estimates of stenosis, patients, and market
opportunity and explain how you calculated an estimated market opportunity in
the US of approximately $3.3 billion based on these estimates. Please also clarify
whether your estimated market opportunity is based on patients with a CCTA
showing 40% to 90% stenosis, or "a majority of patients experiencing acute chest
pain."
You disclose that "[w]e believe our Heartflow Plaque Analysis is applicable to
approximately 60% of NIT patients annually and the majority of patients
experiencing acute chest pain, which represents 5.5 million patients and an
estimated market opportunity of an incremental approximately $1.7 billion in the
United States." Please provide the data and assumptions supporting your estimates
related to the proportion of NIT patients and number of patients disclosed. In
addition, please discuss how your "limited market education efforts" for •7.

March 5, 2025
Page 4
Heartflow Plaque Analysis impact your market opportunity estimates for this
product.
8.We note your disclosure that your current focus is on the United States but that you
"also have a commercial presence and regulatory approval in certain international
markets, including the United Kingdom, European Union and Japan, which [you]
estimate represents an additional 4.2 million potential CCTA patients." Please provide
relevant sources, data, and assumptions supporting your estimate of the potential
CCTA patients in these international markets.
The Offering, page 12
9.We note your disclosure that "[i]n connection with the completion of this offering,
[you] are obligated to use certain of the net proceeds from this offering to repay $50.0
million (or $55.0 million if the underwriters exercise their option to purchase
additional shares of common stock) of the indebtedness outstanding under the
amended credit agreement and guaranty (the “2024 Credit Agreement”) with Hayfin
Services, LLP (“Hayfin”) and to pay...fees in connection therewith." Please revise to
briefly discuss your relationship to Hayfin, including the percentage of your beneficial
ownership held by entities affiliated with Hayfin.
10.Please revise your disclosure to describe the lock-up agreements discussed on pages
63 and 179 of your registration statement.
Summary consolidated financial data, page 15
11.Please expand your statement of operations and balance sheet pro forma presentations
to include an adjustment for the stock-based compensation expense for the restricted
stock unit that will be granted concurrently with the offering as disclosed on page 13,
along with disclosures that disclose the material terms of the grant, the total amount of
compensation expense to be recognized, the period over which the expense will be
recognized, and the assumptions used to estimate the compensation expense. Refer to
Article 11-02(a)(8) of Regulation S-X for guidance. Please address this comment for
all of your pro forma presentations.
12.Please expand your statement of operations pro forma presentation to include an
adjustment for the interest expense and change in fair value of derivative liability, if
any, associated with the $50 million repayment for the 2024 Credit Agreement. Please
address this comment for all of your pro forma presentations.
Risk Factors
To date we have derived a significant amount of our revenue from a small number of
customers, and face risks associated with a more..., page 21
We note your disclosure that "although [y]our Heartflow Platform had an installed
base of over 1,100 accounts in the United States as of December 31, 2024, the
decision-making function for many of these accounts is concentrated in a relatively
small number of customers, such that the loss of one customer could result in a
disproportionate loss across [y]our accounts." We also note your disclosure on page
82 that "[n]o single customer accounted for 10% or more of [y]our revenue during the
year ended December 31, 2023." Please revise, here and on page 82, to reconcile these 13.

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Page 5
two statements, including whether a "disproportionate loss" across accounts would
result in a similar loss to your revenue, and note whether any customer accounted for
more than 10% of your revenue during the year ended December 31, 2024. Please
also revise your disclosures on page 82 to clarify the difference, if any, between your
installed base of accounts and customers.
Our Heartflow Platform and the data and models it generates could have bugs, defects or
errors, including human quality control errors..., page 25
14.We note your disclosure that "[you] have in the past, and may in the future,
experience defects or errors in [y]our Heartflow Platform or the data and models it
generates that remain undetected by [y]our analyst-based review process." Please
revise to briefly discuss, if material, these prior defects or errors in the Heartflow
Platform or the data and models it generates, including any related negative impacts
on your business or operations. We also note your disclosure on page 39 that
"[yo]ur products have been in the past, and may in the future, be the subject of
medical device reports of adverse events with the FDA’s Manufacturer and User
Facility Device Experience database, including reports of false negative results and
incorrect or imprecise results or readings." Please revise to briefly discuss these past
medical device reports of adverse events, if material, including any reports of false
negative results and incorrect or imprecise results or readings, and the related impact
on your business or operations.
Off-label or other unlawful promotion of our products could result in costly investigations
and sanctions from the FDA and other..., page 39
15.We note your disclosure here and throughout the filing that the Heartflow Platform
has been "cleared by the FDA, and the equivalent regulatory authorities in Israel,
Saudi Arabia, United Arab Emirates, licensed in Bahrain, CE Marked in the European
Economic Area, the United Kingdom and Australia, received medical device licensing
in Canada and been approved for marketing authorization in Japan by the
Pharmaceuticals and Medical Devices Agency (“PMDA”), all for specific indications
for use." We also note your disclosure on page 125 that "[o]nly the FFRCT Analyses
is authorized for clinical use in the European Economic Area, United Kingdom,
Australia, Canada, and Japan," and that the "Heartflow Platform is regulated in the
United States by the FDA as a Class II medical device." Here and in your prospectus
summary, please revise to note, as you do on page 25, the specific FDA authorization
received by your Heartflow Platform and each of the products within your Heartflow
Platform. Please also revise your disclosure on page 39 to clarify that only the
FFRCT, and not your Heartflow Platform, is authorized for clinical use in the EEA,
the UK, Australia, Canada, and Japan. Please also briefly discuss, or cross-reference
to your disclosures elsewhere, the significance of CE Mark, PMDA, and medical
device licensing approval outside of the United States. Finally, we note your
disclosure on page 36 that you "currently have ongoing responsibilities under U.S.,
U.K., European Economic Area, Switzerland, Canada, Australia, Japan, Saudi Arabia,
United Arab Emirates, Bahrain and Israel (registered or licensed regions) regulations."
Please revise to clarify the nature of the ongoing responsibilities, including whether
each of your products is authorized for clinical use in each of these listed jurisdictions.

March 5, 2025
Page 6
Market and Industry Data, page 70
16.We note your disclosure that "[t]his prospectus contains estimates, projections, and
other information concerning our industry and our business, as well as data regarding
market research, estimates, and forecasts prepared by our management or third parties,
including but not limited to, Clarivate." Please revise your disclosure throughout to
cite to specific sources prepared by third parties, where appropriate. In addition,
please tell us whether you commissioned any industry or market data that you
reference in the prospectus, including from Clarivate. If so, file consents of the
relevant third parties pursuant to Rule 436 of the Securities Act as exhibits to your
registration statement.
Use of Proceeds, page 71
17.We note your disclosure that "[you] expect to use the remainder of the net proceeds
from this offering, together with [y]our existing cash and cash equivalents, to fund
[y]our sales and marketing efforts, fund research and product development activities
and for other general corporate purposes, including working capital, operating
expenses, and capital expenditures." Please revise to briefly discuss these planned
research and product development activities, including the specific product(s) for
which you intend to use these proceeds. Refer to Item 504 of Regulation S-K.
Management's Discussion and Analysis of Financial Condition and Results of Operations
Components of our results of operations, page 82