EXHIBIT 4.3 SECOND SUPPLEMENTAL INDENTURE Supplemental Indenture (this "Supplemental Indenture"), dated as of April 30, 2004 among the entities listed in Exhibit A hereto (each a "Guaranteeing Subsidiary" and together the "Guaranteeing Subsidiaries"), each a subsidiary of Renal Care Group, Inc., Renal Care Group, Inc. (as successor to National Nephrology Associate, Inc.), a Delaware corporation (the "Company"), the Guarantors (as defined in the Indenture referred to herein) and Wells Fargo Bank, National Association, a national banking association (as successor by merger to Wells Fargo Bank Minnesota, N.A.), as trustee under the Indenture referred to below (the "Trustee"). W I T N E S S E T H WHEREAS, the Company has heretofore become a party to an indenture (the "Indenture"), dated as of October 22, 2003 providing for the issuance of 9% Senior Subordinated Notes due 2011 (the "Notes"); WHEREAS, the Indenture provides that under certain circumstances the Guaranteeing Subsidiaries shall execute and deliver to the Trustee a supplemental indenture pursuant to which each Guaranteeing Subsidiary shall unconditionally guarantee all of the Company's obligations under the Notes and the Indenture on the terms and conditions set forth herein (the "Guarantee"); and WHEREAS, pursuant to Section 9.01 of the Indenture, the Trustee is authorized to execute and deliver this Supplemental Indenture. NOW THEREFORE, in consideration of the foregoing and for other good and valuable consideration, the receipt of which is hereby acknowledged, each Guaranteeing Subsidiary and the Trustee mutually covenant and agree for the equal and ratable benefit of the Holders of the Notes as follows: 1. Capitalized Terms. Capitalized terms used herein without definition shall have the meanings assigned to them in the Indenture. 2. Agreement to Guarantee. Each Guaranteeing Subsidiary hereby agrees as follows: (a) Along with all other Guarantors, to jointly and severally Guarantee to each Holder of a Note authenticated and delivered by the Trustee and to the Trustee and its successors and assigns, irrespective of the validity and enforceability of the Indenture, the Notes or the obligations of the Company hereunder or thereunder, that: (i) the principal of and interest on the Notes will be promptly paid in full when due, whether at maturity, by acceleration, redemption or otherwise, and interest on the overdue principal of and interest on the Notes, if any, if lawful, and all other obligations of the Company to the Holders or the Trustee hereunder or thereunder will be promptly paid in full or performed, all in accordance with the terms hereof and thereof; and 1 (ii) in case of any extension of time of payment or renewal of any Notes or any of such other obligations, the same will be promptly paid in full when due or performed in accordance with the terms of the extension or renewal, whether at stated maturity, by acceleration or otherwise. Failing payment when due of any amount so guaranteed or any performance so guaranteed for whatever reason, the Guarantors shall be jointly and severally obligated to pay the same immediately. (b) The obligations hereunder shall be unconditional, irrespective of the validity, regularity or enforceability of the Notes or the Indenture, the absence of any action to enforce the same, any waiver or consent by any Holder of the Notes with respect to any provisions hereof or thereof, the recovery of any judgment against the Company, any action to enforce the same or any other circumstance that might otherwise constitute a legal or equitable discharge or defense of a guarantor. (c) The following are hereby waived: diligence, presentment, demand of payment, filing of claims with a court in the event of insolvency or bankruptcy of the Company, any right to require a proceeding first against the Company, protest, notice and all demands whatsoever. (d) This Guarantee shall not be discharged except by complete performance of the obligations contained in the Notes and the Indenture. (e) If any Holder or the Trustee is required by any court or otherwise to return to the Company, the Guarantors, or any Custodian, Trustee, liquidator or other similar official acting in relation to either the Company or the Guarantors, any amount paid by either to the Trustee or such Holder, this Guarantee, to the extent theretofore discharged, shall be reinstated in full force and effect. (f) Such Guaranteeing Subsidiary shall not be entitled to any right of subrogation in relation to the Holders in respect of any obligations guaranteed hereby until payment in full of all obligations guaranteed hereby. (g) As between the Guarantors, on the one hand, and the Holders and the Trustee, on the other hand, (x) the maturity of the obligations guaranteed hereby may be accelerated as provided in Article Six of the Indenture for the purposes of this Guarantee, notwithstanding any stay, injunction or other prohibition preventing such acceleration in respect of the obligations guaranteed hereby, and (y) in the event of any declaration of acceleration of such obligations as provided in Article Six of the Indenture, such obligations (whether or not due and payable) shall forthwith become due and payable by the Guarantors for the purpose of this Guarantee. (h) Pursuant to Section 10.02 of the Indenture, after giving effect to any maximum amount and any other contingent and fixed liabilities that are relevant under any applicable Bankruptcy or fraudulent conveyance laws, and after giving effect to any collections from, rights to receive contribution from or payments made by or on behalf of any other Guarantor in respect of the obligations of such other Guarantor under Article Ten of the Indenture shall result in the obligations of such Guarantor under its Guarantee not constituting a fraudulent transfer or conveyance. 2 3. Subordination. The Obligations of the Guaranteeing Subsidiary under its Guarantee pursuant to this Supplemental Indenture shall be junior and subordinated to the Senior Indebtedness of the Guaranteeing Subsidiary on the same basis as the Notes are junior and subordinated to the Senior Indebtedness of the Company. For the purposes of the foregoing sentence, the Trustee and the Holders shall have the right to receive and/or retain payments by the Guaranteeing Subsidiary only at such time as they may receive and/or retain payments in respect of the Notes pursuant to the Indenture, including Article Ten thereof. 4. Execution and Delivery. Each Guaranteeing Subsidiary agrees that the Guarantees shall remain in full force and effect notwithstanding any failure to endorse on each Note a notation of such Guarantee. 5. Guaranteeing Subsidiary May Consolidate, Etc., on Certain Terms. Except as otherwise provided in Section 11.05 of the Indenture, a Guarantor may not consolidate with or merge with or into any other Person or convey, sell, assign, transfer, lease or otherwise dispose of its properties and assets substantially as an entirety to any other Person (other than the Company or another Guarantor) unless: (i) subject to the provisions of the following paragraph, the Person formed by or surviving such consolidation or merger (if other than such Guarantor) or to which such properties and assets are transferred assumes all of the obligations of such Guarantor under this Indenture and its Guarantee, pursuant to a supplemental indenture in form and substance satisfactory to the Trustee; (j) immediately after giving effect to such transaction, no Default or Event of Default has occurred and is continuing; and (k) the Guarantor delivers, or causes to be delivered, to the Trustee, in form and substance reasonably satisfactory to the Trustee, an Officers' Certificate and an Opinion of Counsel, each stating that such transaction complies with the requirements of this Indenture. For purposes of the foregoing, the transfer (by lease, assignment, sale or otherwise, in a single transaction or series of transactions) of all or substantially all of the properties or assets of one or more Restricted Subsidiaries, the Capital Stock of which constitutes all or substantially all of the properties and assets of the Company, shall be deemed to be the transfer of all or substantially all of the properties and assets of the Company. In case of any such consolidation, merger, sale or conveyance and upon the assumption by the successor Person, by supplemental indenture, executed and delivered to the Trustee and reasonably satisfactory in form to the Trustee, of the Guarantee endorsed upon the Notes and the due and punctual performance of all of the covenants and conditions of the Indenture to be performed by a Guarantor, such successor Person shall succeed to and be substituted for a Guarantor with the same effect as if it had been named herein as a Guarantor. Such successor Person thereupon may cause to be signed any or all of the Guarantees to be endorsed upon all of the Notes issuable hereunder which theretofore shall not have been signed by the Company and delivered to the Trustee. All the Guarantees so issued shall in all respects have the same legal rank and benefit under the Indenture as the Guarantees theretofore and thereafter issued in accordance 3 with the terms of the Indenture as though all of such Guarantees had been issued at the date of the execution hereof. 6. Releases. (a) A Guarantor will be deemed automatically and unconditionally released and discharged from all of its obligations under its Guarantee without any further action on the part of the Trustee or any Holder of the Notes upon a sale or other disposition to a Person not an Affiliate of the Company of all of the Capital Stock of, or all or substantially all of the assets of, such Guarantor, by way of merger, consolidation or otherwise, which transaction is carried out in accordance with Section 4.10 hereof; provided that any such termination shall occur (x) only to the extent that all obligations of such Guarantor under all of its guarantees of, and under all of its pledges of assets or other security interests which secure any Indebtedness of the Company shall also terminate upon such sale, disposition or release and (y) only if the Trustee is furnished with written notice of such release together with an Officers' Certificate from such Guarantor to the effect that all of the conditions to release in this Section 6 have been satisfied. (b) Any Guarantor not released from its obligations under its Guarantee shall remain liable for the full amount of principal of and interest on the Notes and for the other obligations of any Guarantor under the Indenture as provided in Article Eleven of the Indenture. 7. No Recourse Against Others. No director, officer, employee, incorporator or stockholder of the Company or any Guarantor, as such, shall have any liability for any obligations of the Company or the Guarantors under the Notes, this Indenture, the Guarantees or for any claim based on, in respect of, or by reason of, such obligations or their creation. Each Holder of Notes by accepting a Note waives and releases all such liability. The waiver and release are part of the consideration for issuance of the Notes. The waiver may not be effective to waive liabilities under the federal securities laws. 8. NEW YORK LAW TO GOVERN. THE INTERNAL LAW OF THE STATE OF NEW YORK SHALL GOVERN AND BE USED TO CONSTRUE THIS SUPPLEMENTAL INDENTURE BUT WITHOUT GIVING EFFECT TO APPLICABLE PRINCIPLES OF CONFLICTS OF LAW TO THE EXTENT THAT THE APPLICATION OF THE LAWS OF ANOTHER JURISDICTION WOULD BE REQUIRED THEREBY. 9. Counterparts. The parties may sign any number of copies of this Supplemental Indenture. Each signed copy shall be an original, but all of them together represent the same agreement. 10. Effect of Headings. The Section headings herein are for convenience only and shall not affect the construction hereof. 11. Trustee. The Trustee shall not be responsible in any manner whatsoever for or in respect of the validity or sufficiency of this Supplemental Indenture or for or in respect of the recitals contained herein, all of which recitals are made solely by the Guaranteeing Subsidiary and the Company. 4 IN WITNESS WHEREOF, the parties hereto have caused this Supplemental Indenture to be duly executed and attested, all as of the date first above written. Dated: April 30, 2004 GUARANTEEING SUBSIDIARIES: RENAL CARE GROUP EAST, INC., a Pennsylvania corporation RENAL CARE GROUP MICHIGAN, INC., a Delaware corporation MICHIGAN HOME DIALYSIS CENTER, INC., a Michigan corporation RENAL CARE GROUP OF THE MIDWEST, INC., a Kansas corporation FOUR STATE REGIONAL DIALYSIS CENTER, INC., a Missouri corporation FORT SCOTT REGIONAL DIALYSIS CENTER, INC., a Missouri corporation MIAMI REGIONAL DIALYSIS CENTER, INC., a Missouri corporation RCG MISSISSIPPI, INC., a Delaware corporation RENAL CARE GROUP OF THE SOUTHEAST, INC., a Florida corporation NORTHEAST ALABAMA KIDNEY CLINIC, INC., an Alabama corporation RENAL CARE GROUP TEXAS, INC., a Texas corporation DIALYSIS MANAGEMENT CORPORATION, a Texas corporation RCG PA MERGER CORP., a Texas corporation STAT DIALYSIS CORPORATION, a Delaware corporation ANGLETON DIALYSIS, INC., a Texas corporation BRAZORIA KIDNEY CENTER, INC., a Texas corporation FONDREN DIALYSIS CLINIC, INC., a Texas corporation WHARTON DIALYSIS, INC., a Texas corporation JEFFERSON COUNTY DIALYSIS, INC., an Arkansas corporation KDCO, INC., a Missouri corporation By: /s/ Douglas B. Chappell ---------------------------------------------- Name: Douglas B. Chappell Title: Vice President and Secretary 5 GUARANTEEING LAWTON DIALYSIS, INC., an Arkansas corporation SUBSIDIARIES (CONTINUED): LITTLE ROCK DIALYSIS, INC., an Arkansas corporation NORTHWEST DIALYSIS, INC., an Arkansas corporation RENALAB, INC., a Delaware corporation RCG FINANCE, INC., a Delaware corporation RENALPARTNERS, INC., a Delaware corporation RENALNET, INC., a Delaware corporation WOUND CARE GROUP, INC., a Delaware corporation DIABETES CARE GROUP, INC., a Delaware corporation RENAL CARE GROUP ARIZONA, INC., an Arizona corporation RENAL CARE GROUP NORTHWEST, INC., a Delaware corporation RENALNET, ARIZONA, INC., an Arizona corporation RCG UNIVERSITY DIVISION, INC., a Tennessee corporation R.C.G. SUPPLY COMPANY, a Tennessee corporation RENAL CARE GROUP ALASKA, INC., an Alaska corporation RENAL CARE GROUP SOUTHWEST HOLDINGS, INC., a Delaware corporation DIALYSIS CENTERS OF AMERICA - ILLINOIS, INC., an Illinois corporation SSKG, INC., an Illinois corporation RENAL CARE GROUP OHIO, INC., a Delaware corporation PHYSICIANS DIALYSIS COMPANY, INC., a Pennsylvania corporation KENTUCKY RENAL CARE GROUP, LLC, a Delaware limited liability company By: /s/ Douglas B. Chappell ---------------------------------------------- Name: Douglas B. Chappell Title: Vice President and Secretary DIALYSIS LICENSING CORP., a Delaware corporation RCGIH, INC., a Delaware corporation By: /s/ Douglas B. Chappell ---------------------------------------------- Name: Douglas B. Chappell Title: Vice President and Assistant Secretary 6 GUARANTEEING RENAL CARE GROUP SOUTHWEST, L.P., a Delaware SUBSIDIARIES (CONTINUED): limited partnership By: Renal Care Group Arizona, Inc., as sole general partner By: /s/ Douglas B. Chappell ----------------------------------------------- Name: Douglas B. Chappell Title: Vice President and Secretary ARIZONA RENAL INVESTMENTS, LLC, a Delaware limited liability company By: Renal Care Group Arizona, Inc., as sole member By: /s/ Douglas B. Chappell ----------------------------------------------- Name: Douglas B. Chappell Title: Vice President and Secretary RCG INDIANA, L.L.C., a Delaware limited liability company By: Renal Care Group, Inc., as manager By: /s/ Douglas B. Chappell ----------------------------------------------- Name: Douglas B. Chappell Title: Senior Vice President and Secretary KIDNEY DISEASE CENTER OF THE OZARKS, L.L.C., a Missouri limited liability company By: Renal Care Group, Inc., as sole member By: /s/ Douglas B. Chappell ----------------------------------------------- Name: Douglas B. Chappell Title: Senior Vice President and Secretary 7 GUARANTEEING STUTTGART DIALYSIS, LLC, an Arkansas limited SUBSIDIARIES (CONTINUED): liability company By: Renal Care Group, Inc., as sole manager By: /s/ Douglas B. Chappell ----------------------------------------------- Name: Douglas B. Chappell Title: Senior Vice President and Secretary RCG WEST HEALTH SUPPLY, L.C., an Arizona limited company By: Renal Care Group, Inc., as member By: /s/ Douglas B. Chappell ----------------------------------------------- Name: Douglas B. Chappell Title: Senior Vice President and Secretary RENAL CARE GROUP TEXAS, LP, a Delaware limited partnership By: RCG PA Merger Corp., as sole general partner By: /s/ Douglas B. Chappell ----------------------------------------------- Name: Douglas B. Chappell Title: Vice President and Secretary RENAL CARE GROUP WESTLAKE, LLC, a Delaware limited liability company By: RCG University Division, Inc., as sole member By: /s/ Douglas B. Chappell ----------------------------------------------- Name: Douglas B. Chappell Title: Vice President and Secretary 8 RENAL CARE GROUP, INC. By: /s/ David M. Dill ----------------------------------------------- Name: David M. Dill Title: Executive Vice President 9 EXISTING GUARANTORS: NNA OF OKLAHOMA, INC., a Nevada corporation NNA OF GEORGIA, INC., a Delaware corporation NNA OF ALABAMA, INC., an Alabama corporation NNA MANAGEMENT COMPANY OF KENTUCKY, INC., a Kentucky corporation NATIONAL NEPHROLOGY ASSOCIATES MANAGEMENT COMPANY OF TEXAS, INC., a Texas corporation NNA OF NEVADA, INC., a Nevada corporation NATIONAL NEPHROLOGY ASSOCIATES CREDIT CORPORATION, a Tennessee corporation NNA OF TOLEDO, INC., an Ohio corporation NNA PROPERTIES OF NEW JERSEY, INC., a New Jersey corporation NNA MANAGEMENT COMPANY OF LOUISIANA, INC., a Louisiana corporation RENEX CORP., a Florida corporation RENEX MANAGEMENT SERVICES, INC., a Florida corporation DIALYSIS SERVICES OF ATLANTA, INC., a Georgia corporation RENEX DIALYSIS CLINIC OF PENN HILLS, INC., a Pennsylvania corporation RENEX DIALYSIS CLINIC OF SHALER, INC., a Pennsylvania corporation RENEX DIALYSIS CLINIC OF DOYLESTOWN, INC., a Pennsylvania corporation RENEX DIALYSIS CLINIC OF AMESBURY, INC., a Massachusetts corporation RENEX DIALYSIS CLINIC OF NORTH ANDOVER, INC., a Massachusetts corporation RENEX DIALYSIS CLINIC OF SOUTH GEORGIA, INC., a Georgia corporation RENEX DIALYSIS CLINIC OF CREVE COUER, INC., a Missouri corporation RENEX DIALYSIS CLINIC OF ST. LOUIS, INC., a Missouri corporation By: /s/ David M. Dill ----------------------------------------------- Name: David M. Dill Title: Vice President 10 EXISTING GUARANTORS RENEX DIALYSIS CLINIC OF BRIDGETON, INC., a (CONTINUED): Missouri corporation RENEX DIALYSIS CLINIC OF UNION, INC., a Missouri corporation RENEX DIALYSIS HOMECARE OF GREATER ST. LOUIS, INC., a Missouri corporation RENEX DIALYSIS CLINIC OF MAPLEWOOD, INC., a Missouri corporation RENEX DIALYSIS CLINIC OF UNIVERSITY CITY, INC., a Missouri corporation RENEX DIALYSIS FACILITIES, INC., a Mississippi corporation RENEX DIALYSIS CLINIC OF BLOOMFIELD, INC., a New Jersey corporation RENEX DIALYSIS CLINIC OF ORANGE, INC., a New Jersey corporation RENEX DIALYSIS CLINIC OF PHILADELPHIA, INC., a Pennsylvania corporation RENEX DIALYSIS CLINIC OF PITTSBURGH, INC., a Pennsylvania corporation RENEX DIALYSIS CLINIC OF WOODBURY, INC., a New Jersey corporation RENEX DIALYSIS CLINIC OF TAMPA, INC., a Florida corporation NNA PROPERTIES OF KENTUCKY, INC., a Kentucky corporation NNA PROPERTIES OF TENNESSEE, INC., a Tennessee corporation NNA TRANSPORTATION SERVICES CORPORATION, a Tennessee corporation By: /s/ David M. Dill ----------------------------------------------- Name: David M. Dill Title: Vice President NATIONAL NEPHROLOGY ASSOCIATES OF TEXAS, L.P., a Texas limited partnership By: National Nephrology Associates Management Company of Texas, Inc., a Texas corporation, as general partner By: /s/ David M. Dill ---------------------------------------- Name: David M. Dill Title: Vice President 11 EXISTING GUARANTORS NNA - SAINT BARNABAS, L.L.C., a New Jersey limited (CONTINUED): liability company By: Renex Dialysis Clinic of Woodbury Inc., a Delaware corporation, as sole member NNA - SAINT BARNABAS - LIVINGSTON, L.L.C., a New Jersey limited liability company By: NNA - Saint Barnabas, LLC, a New Jersey limited liability company, as sole member By: Renex Dialysis Clinic of Woodbury Inc., a Delaware corporation, as sole member NNA OF OKLAHOMA, L.L.C., an Oklahoma limited liability company By: NNA of Oklahoma, Inc., a Nevada corporation, as sole member NNA OF LOUISIANA, LLC, a Louisiana limited liability company By: NNA Management Company of Louisiana, Inc., as sole member DOYLESTOWN ACUTE RENAL SERVICES, L.L.C., a Pennsylvania limited liability company By: Renex Dialysis Clinic of Doylestown, Inc., a Pennsylvania corporation, as sole member NNA OF NEWARK, L.L.C., a New Jersey limited liability company By: Renex Dialysis Clinic of Woodbury, Inc., a New Jersey corporation, as sole member By: /s/ David M. Dill ----------------------------------------------- Name: David M. Dill Title: Vice President NNA OF RHODE ISLAND, INC., a Rhode Island corporation By: /s/ Leif Murphy ----------------------------------------- Name: Leif Murphy Title: Executive Vice President 12 EXISTING GUARANTORS DIALYSIS ASSOCIATES, LLC, a Tennessee limited (CONTINUED): liability company DIALYSIS ASSOCIATES MEDICAL SUPPLY, LLC, a Tennessee limited liability company By: Renal Care Group, Inc., a Delaware corporation, as sole member By: /s/ David M. Dill ---------------------------------------- Name: David M. Dill Title: Executive Vice President and Chief Financial Officer 13 WELLS FARGO BANK MINNESOTA, N.A., AS TRUSTEE By: /s/ Jane Y. Schweiger ---------------------------------------------- Name: Jane Y. Schweiger Title: Vice President 14 EXHIBIT A Guaranteeing Subsidiaries Renal Care Group East, Inc. Renal Care Group Michigan, Inc. Michigan Home Dialysis Center, Inc. Renal Care Group of the Midwest, Inc. Four State Regional Dialysis Center, Inc. Fort Scott Regional Dialysis Center, Inc. Miami Regional Dialysis Center, Inc. RCG Mississippi, Inc. Renal Care Group of the Southeast, Inc. Northeast Alabama Kidney Clinic, Inc. Renal Care Group Texas, Inc. Dialysis Management Corporation RCG PA Merger Corp. STAT Dialysis Corporation Angleton Dialysis, Inc. Brazoria Kidney Center, Inc. Fondren Dialysis Clinic, Inc. Wharton Dialysis, Inc. Jefferson County Dialysis, Inc. KDCO, Inc. Lawton Dialysis, Inc. Little Rock Dialysis, Inc. Northwest Dialysis, Inc. RenaLab, Inc. RCG Finance, Inc. RenalPartners, Inc. RenalNet, Inc. Wound Care Group, Inc. Diabetes Care Group, Inc. Renal Care Group Arizona, Inc. Renal Care Group Northwest, Inc. RenalNet, Arizona, Inc. RCG University Division, Inc. R.C.G. Supply Company Renal Care Group Alaska, Inc. Renal Care Group Southwest Holdings, Inc. Dialysis Centers of America - Illinois, Inc. SSKG, Inc. Renal Care Group Ohio, Inc. Physicians Dialysis Company, Inc. Dialysis Licensing Corp. RCGIH, Inc. -A1- Renal Care Group Southwest, L.P. Arizona Renal Investments, LLC RCG Indiana, L.L.C. Kidney Disease Center of the Ozarks, L.L.C. Stuttgart Dialysis, LLC RCG West Health Supply, L.C. Kentucky Renal Care Group, LLC Renal Care Group Texas, LP Renal Care Group Westlake, LLC -A2-