INTRODUCTION THIS SYNOPSIS IS A NON-COMPETITIVE NOTICE OF INTENT TO AWARD A MODIFICATION TO INCREASE THE INDEFINITE-DELIVERY/INDEFINITE-QUANTITY (IDIQ) CEILING OF CONTRACT NO. 75N92019D00027 AND EXTEND THE PERIOD OF PERFORMANCE BY NINE (9) MONTHS WITHOUT PROVIDING FOR FULL AND OPEN COMPETITION (INCLUDING BRAND-NAME). This acquisition is conducted under the authority of 41 United States Code (U.S.C.) 3304(a)(1), as set forth in RFO – Federal Acquisition Regulation (FAR) 6.103-1, Only one responsible source and no other supplies or services will satisfy agency requirements. The National Heart, Lung, and Blood Institute (NHLBI) intends to award a modification to Indefinite-Delivery/Indefinite-Quantity (IDIQ) Contract No. 75N92019D00027, facilitating the requirements of the core study operational activities outlined in Task Area A of the Statement of Work (SOW), for the Strong Heart Study (SHS) – Coordinating Center (CC), without providing for full and open competition (including brand-name) to The University of Oklahoma Health Sciences Center (OUHSC). The IDIQ ceiling value for Contract No. 75N92019D00027 will be increased through a modification action to accommodate one (1) additional nine (9) month option period to continue core study operational activities outlined in the Statement of Work (SOW) for the Coordinating Center (CC). It is anticipated that the modification will be issued around January 2027. THIS IS A SYNOPSIS. THIS IS NOT A SOLICITATION. BACKGROUND AND PROGRAM OBJECTIVES The Strong Heart Study (SHS) is the largest, multi-center longitudinal observational epidemiological study of cardiovascular disease (CVD) in Native Americans / American Indians (AI/AN). The study's primary objective is to examine the incidence and prevalence of CVD in this population, identify genetic, additional risk factors, assess co-morbidities of CVD and monitor morbidity and mortality. Initiated in 1989, the study recruited 4,549 unrelated individuals from 13 tribes and communities across three (3) US regions: Arizona (AZ); North and South Dakota (ND, SD); and Oklahoma (OK). Participants in the original cohort were recruited regardless of their disease status and underwent clinical examinations three (3) times between 1989 and 1999, once in each phase (I through III) of the study. In phase IV (beginning in 1998), a second cohort known as the Strong Heart Family Study (SHFS) was established adding 3,790 individuals from 94 multigenerational families from the original cohort. The SHFS aimed to complement the original SHS and to enhance understanding of the heritability of CVD and its risk factors in AI/AN populations. During phase V of the study, which concluded in 2009, participants received another clinical examination. During phase VI of the study (2013-2018), funding was focused on surveillance activities, data analysis, and infrastructure support. Currently, in phase VII (2019-2027), the SHS is funded for clinical examinations, surveillance activ…