The Missing Dimensions in LVAD Diffusion: Geographic Access and Medical Therapy Optimization.

Despite major advances in durable left ventricular assist device (LVAD) technology, implantation volumes have remained relatively stagnant, and LVAD therapy has not entered mainstream cardiovascular practice. Recent work has framed this as a diffusion failure driven by delayed referral, uneven institutional learning, and economic and policy misalignment. We propose that two upstream, interacting determinants deserve greater attention: geographic access to advanced heart failure (HF) care and optimization of guideline-directed medical therapy (GDMT) before assessing eligibility for advanced therapies. Geography influences whether patients reach specialist care, receive contemporary GDMT, undergo timely reassessment, and remain connected to longitudinal LVAD follow-up. These gaps also complicate the denominator of "LVAD-eligible" patients: some may be under-referred despite refractory disease, whereas others may be undertreated before advanced therapy candidacy is established. National models further illustrate the distinction between adoption and equity. Türkiye experienced rapid expansion of durable mechanical circulatory support after reimbursement barriers were resolved in 2012, whereas the Kazakhstan model highlights coordinated national investment. Both demonstrate the importance of policy support, but neither national volume nor program growth alone establishes equitable geographic diffusion. Future registries and data reports should therefore integrate geographic and socioeconomic variables to distinguish LVAD underuse from structural under-access to optimal advanced HF care.