Hemodynamic Homeostasis · §9 · M = spinodal(κ) − |load|

Fundamental vs symptomatic treatment of hypertension and heart failure

The loop structure makes a sharp, falsifiable split. In hypertension, durable benefit tracks a renal-REFERENCE reset (durable −17 mmHg) not an operating-point push (durable 0). In heart failure, mortality benefit tracks the barrier margin M = spinodal(κ) − |load|: load reduction + cycle break grows it (+0.180) while inotrope flogging shrinks it (-0.139). Direction [V], anchors [L], absolute [O].

Treating the setpoint/basin, not the operating point/effector, is the fundamental move. Hypertension durability follows reference reset (durable −17 mmHg) over operating-point pushes (durable 0); heart-failure mortality follows growth of M = spinodal(κ) − |load| (load-reduce +0.180) over effector flogging (inotrope -0.139). Direction reproduced [V], effect sizes cited [L]/open [O].

Hypertension: reset the renal reference, do not push the operating point

Durable blood-pressure reduction tracks how much a therapy resets the renal reference, not how much it pushes the operating point — a direct consequence of the integral controller of the slow loop. In the model a reference reset gives a durable drop of 17 mmHg and holds, whereas an operating-point drug is opposed back to a durable drop of 0 mmHg (research target T1). The loop says, in advance, which class of therapy should be durable.

The clinical evidence agrees in direction. Renal denervation — a reference-level intervention — produces a durable, time-increasing effect (FDA-approved 2023; registry office SBP on the order of −20 mmHg at 3 years), and durable control needs a diuretic/renal backbone, because a vasodilator-only operating-point push is rejected by the integrator back toward the reset reference [L]. The package asserts the direction [V]; absolute effect sizes are open [O] and are anchored to clinical units in the calibration chapter.

Heart failure: grow the margin, never flog the pump

Mortality benefit in heart failure tracks the barrier margin M = spinodal(κ) − |load|, which turns “what helps?” into a single signed quantity. Load reduction plus interruption of the maladaptive neurohormonal cycle GROWS the margin (ΔM = +0.180, basin restored), while a positive inotrope SHRINKS it (ΔM = -0.139, accelerated collapse) (T2). A therapy that improves the numbers on the monitor while shrinking the margin is buying haemodynamics at the cost of the attractor.

This matches the evidence in both directions, which is the strong test. Effector flogging is harmful — oral milrinone raised mortality (PROMISE) despite better haemodynamics — while the four pillars that reduce load or break the cycle each lower mortality: ARNI (PARADIGM-HF), beta-blockers (CIBIS-II/MERIT-HF/COPERNICUS), MRA (RALES/EMPHASIS-HF) and SGLT2 inhibitors (DAPA-HF/EMPEROR-Reduced/DELIVER) [L]. The SGLT2-inhibitor arm acts through the macula-densa sensor of the sensory chapter, closing the loop from a molecular transducer to a mortality benefit.