Bia Santana, Daniel

Research interests

(1) Cardiovascular Hemodynamics Group:

In 2001, after completing an internship related to training in theoretical and practical aspects of arterial biomechanics (e.g., surgeries for the implantation of intra-cardiovascular sensors), and planning to initiate binational cooperation with researchers from the Dr. René Favaloro University Foundation (FURF, Argentina), I co-participated in the creation of the Cardiovascular Hemodynamics Group (Faculty of Medicine [FMED], UdelaR). Initially, research lines were developed exclusively in animal models (ovine, porcine); over time, enhancing the work required complementing animal recordings with records from hemodynamic simulators, enabling the study of the same blood vessel under controlled conditions (e.g., pressure, shear stress). This necessitated original research to construct and validate simulators (e.g., obtaining and adjusting an artificial heart for these purposes, mimicking real hemodynamic curves). By employing both approaches, the work contributes to generating knowledge on: (i) the role of vascular smooth muscle (VSM) in physiological and pathophysiological situations, (ii) the passive-active role of the endothelium and/or adventitia in modulating vascular viscoelasticity, (iii) characterizing regional differences in viscoelasticity and its relationship with wall constituents, (iv) characterizing arterial biomechanical changes and the role of VSM, endothelium, and adventitia in heart failure, hypertension models, etc., and during therapies (e.g., aortic counterpulsation, pharmacological treatments), and (v) developing physical-mathematical models aimed at characterizing vascular wall dynamics.

The availability of simulators (2005) allowed for the initiation of cooperation with the current National Institute of Donation and Transplantation (INDT, FMED-UdelaR), aiming to develop and validate cryopreservation techniques for arteries (of different histological types) and human veins, to maintain their viscoelastic properties intact after months of cryopreservation and storage in the bank. These pre-implant studies generated evidence on cryopreservation techniques and the use of cryopreserved homografts for biotherapeutic purposes. These results led to the need to evaluate the post-implant behavior (in the recipient patient) of cryopreserved homografts; generating the necessity to train in non-invasive vascular evaluation techniques for humans. Subsequently, in 2008, we contributed knowledge on the biomechanical coupling level reached by donor and recipient arteries post-implantation. Undertaking this approach (non-invasive studies) generated the idea of creating a university-based research and diagnostic service (human), which would include techniques that did not exist in the country until that point.

(2) CUiiDARTE Interdisciplinary Group:

In 2010, we created the Interdisciplinary Group (Core) "Centro Universitario de Investigación y Diagnóstico Arterial" (University Center for Research, Innovation, and Arterial Diagnosis"; CUiiDARTE), setting up an Experimental Laboratory in FMED in 2012, and the CUiiDARTE-Adults (Hospital de Clínicas; operational until 2016) and CUiiDARTE-Pediatric (Pereira-Rossell Hospital Center, CHPR; operational since 2014) centers in 2012 and 2014, respectively. The common denominator of the lines of work is the study of the human cardiovascular system using non-invasive evaluation techniques. Since then, CUiiDARTE has become a scientific-technological platform for the development of multiple projects, largely generated by questions arising from biomedical professionals with a clinical profile. Inextricably linked to conducting research is the provision of diagnostic services (NOVA AWARD 2012, 2013), free or prepaid, generating extra-budgetary income for FMED-UdelaR, which helps finance CUiiDARTE's activities and expenses.

Notable projects focus on aspects related to: (i) multi-regional cardiovascular structure-function, and their changes and/or differences during pregnancy, physical activity, intrauterine conditions, etc.; (ii) arterial pathophysiology/medicine (e.g., the impact of renal failure, hypertension, heart failure, diabetes, hypertensive states during pregnancy, nutritional disorders); (iii) therapeutic actions (e.g., hemodialysis, cardiac resynchronization, use of antihypertensive drugs). The research strategies allowed for the creation, as a distinctive feature of CUiiDARTE, a significant database that allows investigation of: (i) cardiovascular structural-functional changes during growth and/or aging, and the non-linear mediating/modulating role of cofactors (e.g., sex, physical activity, exposure to risk factors), (ii) identifying continuous reference values (regression methods with fractional polynomials), for diagnostic and/or variable typification purposes (identifying equations of mean value and standard deviation), for multiple arterial variables recorded in various arterial territories (e.g., reactivity, stiffness, diameters, thicknesses, velocities/blood flow, aortic pressure, wave reflection parameters), (iii) vascular characteristics specific to different conditions (e.g., diabetes, atherosclerosis), (iv) evaluating the recording techniques themselves (e.g., aortic pressure). The quality and recognition of this database allowed us to integrate and/or participate in the genesis of high-impact international consortia (NCD Risk Factor Collaboration [NCD-RisC]; Youth Vascular Consortium; Global Pulse Wave Velocity Study Group), generating results that guide global policy decisions made by societies and organizations (e.g., WHO). The specialization we have achieved allows us to participate in the development of regional Consensus on non-invasive evaluation (Artery Society; Inter-American Society of Cardiology; Argentine Society of Arterial Hypertension).

(3) LIEBRE Laboratory:

Aiming to enhance the richness of approaches and not only conduct "resting" studies, but also study multisystem responses during "movement," we created the "Biomedical Research and Evaluation Laboratory in Rest and Exercise" (LIEBRE; located at CHPR). LIEBRE is equipped with significant technological capabilities (e.g., gas analyzers/ergospirometry, impedance cardiology, electrocardiography, tonometry, ultrasound, near-infrared spectroscopy [NIRS], accelerometry/GPS, strength evaluation systems, bioimpedance, electromyography) that allow the assessment of multiple variables in the laboratory and/or in an ambulatory manner (e.g., while the individual performs daily activities). Several projects have been initiated that involve evaluating the impact of certain entities (e.g., pectus excavatum, congenital heart diseases) and physiological conditions (e.g., training) on cardiovascular-respiratory, metabolic, and physical fitness variables (e.g., cardio-respiratory response to exercise, body composition, muscle strength/power).

In this context, my activity aims to develop (institutional construction) interdisciplinary scientific-academic spaces for research, innovation, teaching, human resource training, and extension, where these tasks are integrated with diagnostic activities. Additionally, to generate projects that contribute to the formation of large databases, whose analysis can support decision-making by national and international organizations. I am involved in the creation and management of these spaces, overseeing the scientific-academic management, economic aspects, human resources, planning and development of research projects, diagnostic responsibilities, and human resources training (courses, student supervision), among others. All these aspects are included in the course I have coordinated since 2009 at the Faculty of Medicine.