<PAGE>

                               GUIDANT CORPORATION

EXHIBIT 99.1

               FACTORS POSSIBLY AFFECTING FUTURE OPERATING RESULTS

From time to time, the Company publishes forward-looking statements relating to
anticipated financial performance, business combinations, product development
and regulatory approval timelines, intellectual property matters, market
developments and similar matters. A variety of factors could cause the Company's
actual results to differ materially from those projected, including the
following:

     1. Product development and production factors, including:

          a.   The difficulties and uncertainties inherent in new product
               development, including new products that appear promising during
               development but fail to reach the market or reach the market
               later than expected as a result of safety, performance or
               efficacy concerns, inability to obtain necessary regulatory
               approvals, unanticipated restrictions imposed on approved
               indications, excessive costs to manufacture or technological
               advances by competitors of the Company.

          b.   Unexpected safety, performance, or efficacy concerns arising with
               respect to marketed products, whether or not scientifically
               justified, leading to product recalls, withdrawals, or declining
               sales.

          c.   Unexpected interruptions of manufacturing operations as a result
               of regulatory enforcement actions by the FDA, U.S. Nuclear
               Regulatory Commission, or other regulatory authorities or the
               unavailability of necessary components or materials used in
               manufacturing the Company's products.

     2.   Litigation and other legal factors that could preclude
          commercialization of products or negatively affect the level of sales
          or profitability of existing products, including litigation of product
          liability matters, commercial litigation like the litigation involving
          Cook Incorporated described in the Company's 10-Q or patent
          litigation, which could result in injunctions, the payment of
          royalties or other damages.

     3.   Competitive factors, including:

          a.   The introduction of new products or therapies (including the
               earlier introduction of drug eluting by a competitor or
               competitors, which is expected to negatively impact Company sales
               of non-drug eluting stents) or scientific or medical developments
               that render the Company's existing products less competitive.

          b.   The ability of the Company to obtain intellectual property rights
               sufficient to protect its products or the acquisition of patents
               by competitors that prevent the Company from selling a product or
               including key features in the Company's products.

     4.   Domestic and international governmental factors, including changes to
          laws and regulations, policies and judicial decisions that affect the
          regulation and reimbursement of medical devices, product liability,
          health care reform, or tax laws.


                                       30
<PAGE>


     5.   Health care industry factors, including:

          a.   Increased customer demands for price concessions, reductions in
               third-party reimbursements or refusals to provide reimbursement.


          b.   Limits imposed by customers on the number of manufacturers or
               vendors from which they purchase products.


     6.   Factors relating to business combinations (including the Company's
          previously announced agreement to acquire Cook Group Incorporated),
          including:

          a.   Requirements for regulatory, shareholder, and other approvals and
               the satisfaction or waiver of other conditions (including
               conditions relating to the ACHIEVE System in connection with the
               Cook Group Incorporated acquisition).

          b.   Achievement of targets for synergies, costs, and other
               performance post closing.

     7.   Internal factors, such as retention of key employees (including sales
          employees), changes in business strategies, the impact of
          restructuring and business combinations, and changes in the Company's
          effective tax rate based on changes in the geographic mix of the
          Company's income or acquisitions, if any.


     8.   General economic factors, including changes in foreign currency
          exchange rates, interest rates and inflation.

     9.   Other factors beyond the control of the Company, including earthquakes
          (particularly in light of the fact that the Company has significant
          facilities located near major earthquake fault lines), floods, fires,
          explosions, or acts of terrorism or war.

The Company does not undertake to update its forward-looking statements.

The Company's Annual Report on Form 10-K further describes risks associated with
manufacturing, patents, competition, regulation, third-party reimbursement and
related matters.


                                       31