Venous waterfalls mainly buffer backward pressure transmission

We thank Kenny and Moller for their thoughtful correspondence regarding our review [1].We agree with their central hydraulic point: any Starling-resistor element implies a collapsible segment that can become flow-limiting, and relative to a fully patent conduit, may reduce organ venous drainage.Their analogy with expiratory flow limitation appropriately emphasizes that waterfall behavior should not be interpreted as intrinsically beneficial for venous outflow.A key clarification is that our use of protection was not intended to imply enhanced venous drainage under all conditions.Rather, we used the term in the narrower sense of buffering backward pressure transmission from downstream venous pressures to the microcirculation.In a venous waterfall regime, rises in right atrial pressure (Pra) are not necessarily transmitted linearly to small venules and capillaries until a local threshold is exceeded.This thresholded transmission may delay capillary hypertension, edema formation, and pressure-dependent microvascular injury, and may contribute to territoryspecific vulnerability.In this view, the relevant endpoint is not maximal steady venous outflow, but the degree and timing with which downstream pressures reach the capillary bed.