Raising the pressure: Hemodynamic effects of splanchnic nerve stimulation

Abstract

A number of cardiovascular and neurological diseases are characterized by a dysregulation of intravascular volume distribution. The veins and arteries of the visceral organs form the so-called splanchnic vascular compartment and are the largest reservoir for intravascular blood. The blood localized in the splanchnic compartment can be mobilized in and out of the compartment via passive compression or active neurohormonal recruitment. We studied the hemodynamic effects of splanchnic nerve stimulation during five cases of irreversible electroporation (IRE) in patients with pancreatic cancer. In IRE, repeated bursts of high-voltage electrical fields are applied to visceral beds for >1 min, which induces rapid increase in blood pressure, heart rate, and cardiac output. We present the first analysis into the hemodynamic changes with splanchnic nerve stimulation and explore potential mechanisms of the hyperdynamic state. Our analysis presents the first human report of splanchnic nerve stimulation to induce hypertension and volume redistribution, introducing the splanchnic nerves as a key component of cardiovascular regulation. Our case series provides the first detailed description of human hemodynamic effects with splanchnic nerve stimulation. Splanchnic nerve stimulation results in profound hemodynamic alteration with rapid onset of hypertension and blood mobilization.

Regional adiposity and heart failure with preserved ejection fraction

“…It has been proposed that inter-compartmental volume redistribution from the abdominal/splanchnic compartment into the central compartment (chest and central vasculature) could be a key determinant of cardiovascular congestion and cause of cardiac decompensation. 96,97 Since obesity (especially visceral) is associated with a higher intra-abdominal pressure (IAP), 98,99 the external vascular compression could lead to a restrictive vascular physiology that is similar to the observed epicardial fat-LV distensibility relationship. Related to this, increased IAP ≥12 mmHg has been linked to organ dysfunction in general and renal impairment specifically.…”

Role of Volume Redistribution in the Congestion of Heart Failure

“…In animal experiments, targeted splanchnic nerve stimulation can lead to a recruitment of up to 80% of the splanchnic volume, which, despite adrenalectomy, results in a blood shift of >20% of the total body blood volume . In a human case study, the stimulation of the nerves resulted in an increase in preload (50%) and cardiac output (200%) within 2 minutes . Exercise, orthostasis, and hemorrhage are 3 classic examples of an increased demand or a sudden reduction in effective circulatory volume/preload that require rapid recruitment of the unstressed volume via splanchnic bed vasoconstriction …”

“…24,25 In a human case study, the stimulation of the nerves resulted in an increase in preload (50%) and cardiac output (200%) within 2 minutes. 26 Exercise, orthostasis, and hemorrhage are 3 classic examples of an increased demand or a sudden reduction in effective circulatory volume/preload that require rapid recruitment of the unstressed volume via splanchnic bed vasoconstriction. 12,27 Splanchnic Capacitance in HF In HF, a state of neurohormonal activation, the splanchnic vascular compartment is at the center of volume dysregulation in acute and chronic HF.…”

Splanchnic nerve block for decompensated chronic heart failure: splanchnic-HF

“…1,2 Elevated sympathetic tone may cause decreased vascular compliance of the main storage compartment of intravascular blood volume (splanchnic compartment) and thus precipitate ADHF. 3,4 The splanchnic nerve has been identified as a potential target for patients with ADHF and preliminary haemodynamic/functional outcomes (N = 5) from this study were previously published. 5 Here, the completed Splanchnic-HF trial results are presented including data on haemodynamic changes, functional outcomes, comprehensive mechanistic evaluation of autonomic tone, vascular stiffness and volume shifts, and structural assessment of the heart.…”