The effects of terlipressin on regional hemodynamics and kidney function in experimental hyperdynamic sepsis

Vasopressor Therapy and Blood Pressure Management in the Setting of Acute Kidney Injury

Acute kidney injury (AKI) is common in the setting of shock. Hemodynamic instability is a risk factor for the development of AKI, and pathophysiological mechanisms include loss of renal perfusion pressure and impaired microcirculation. Although restoration of mean arterial pressure (MAP) may mitigate the risk of AKI to some extent, evidence on this is conflicting. Also debatable is the optimal blood pressure needed to minimize the risk of kidney injury. A MAP of 65 mm Hg traditionally has been considered adequate to maintain renal perfusion pressure, and studies have failed to consistently show improved outcomes at higher levels of MAP. Therapeutic options to support renal perfusion consist of catecholamines, vasopressin, and angiotensin II. Although catecholamines are the most studied, they are associated with adverse events at higher doses, including AKI. Vasopressin and angiotensin II are noncatecholamine options to support blood pressure and may improve microcirculatory hemodynamics through unique mechanisms, including differential vasoconstriction of efferent and afferent arterioles within the nephron. Future areas of study include methods by which clinicians can measure renal blood flow in a macrocirculatory and microcirculatory way, a personalized approach to blood pressure management in septic shock using patient-specific measures of perfusion adequacy, and novel agents that may improve the microcirculation within the kidneys without causing adverse microcirculatory effects in other organs.

Terlipressin Improves Renal Function and Reverses Hepatorenal Syndrome in Patients With Systemic Inflammatory Response Syndrome

BACKGROUND & AIMS

Patients with systemic inflammatory response syndrome (SIRS) along with decompensated cirrhosis and renal dysfunction have a poor prognosis and a lower response to treatment. We evaluated the effect of SIRS on the response of hepatorenal syndrome type 1 (HRS-1) to terlipressin.

METHODS

We performed a retrospective study of data from a trial of the effects of terlipressin (1 mg every 6 hours or placebo with concomitant albumin) in 198 patients with HRS-1, performed at 50 investigational sites in the United States and 2 in Canada from October 2010 through February 2013. We identified patients with 2 or more criteria for SIRS, without untreated infections (28 received terlipressin and 30 received placebo), and patients with less than 2 criteria for SIRS (control subjects). Primary endpoints included HRS reversal (a decrease in serum level of creatinine to ≤1.5 mg/dL), confirmed HRS reversal (defined as 2 serum creatinine levels ≤1.5 mg/dL, ≥ 48 hours apart), and survival for 90 days after treatment.

RESULTS

Baseline characteristics were similar between groups, apart from slightly higher white blood cell counts and heart rates, and slightly lower serum levels of bicarbonate in patients with SIRS versus without SIRS. HRS was reversed in 42.9% of patients who received terlipressin with SIRS (12/28) versus 6.7% of patients who received placebo (2/30) (P = .0018); confirmed HRS reversal occurred in 32.1% of patients who received terlipressin with SIRS (9/28) versus 3.3% who received placebo (1/30) (P = .0048). A larger proportion of patients with SIRS who received terlipressin survived for 90 days without a transplant (13/28; 46.4%) than patients with SIRS who received placebo (7/30; 23.3%) (P = .076).

CONCLUSIONS

In an analysis of data from a placebo-controlled study, we found that terlipressin improved renal function and reversed HRS in a higher proportion of patients with HRS-1 and SIRS than patients who received albumin plus placebo. ClincialTrials.gov, number NCT 01143246.

Renal perfusion in sepsis: from macro- to microcirculation

The pathogenesis of sepsis-associated acute kidney injury is complex and likely involves perfusion alterations, a dysregulated inflammatory response, and bioenergetic derangements. Although global renal hypoperfusion has been the main target of therapeutic interventions, its role in the development of renal dysfunction in sepsis is controversial. The implications of renal hypoperfusion during sepsis probably extend beyond a simple decrease in glomerular filtration pressure, and targeting microvascular perfusion deficits to maintain tubular epithelial integrity and function may be equally important. In this review, we provide an overview of macro- and microcirculatory dysfunction in experimental and clinical sepsis and discuss relationships with kidney oxygenation, metabolism, inflammation, and function.

A Selective V(1A) Receptor Agonist, Selepressin, Is Superior to Arginine Vasopressin and to Norepinephrine in Ovine Septic Shock

OBJECTIVE

Selective vasopressin V(1A) receptor agonists may have advantages over arginine vasopressin in the treatment of septic shock. We compared the effects of selepressin, a selective V(1A) receptor agonist, arginine vasopressin, and norepinephrine on hemodynamics, organ function, and survival in an ovine septic shock model.

DESIGN

Randomized animal study.

SETTING

University hospital animal research laboratory.

SUBJECTS

Forty-six adult female sheep.

INTERVENTIONS

Fecal peritonitis was induced in the anesthetized, mechanically ventilated, fluid-resuscitated sheep, and they were randomized in two successive phases. Three late-intervention groups (each n = 6) received IV selepressin (1 pmol/kg/min), arginine vasopressin (0.25 pmol [0.1 mU]/kg/min), or norepinephrine (3 nmol [0.5 μg]/kg/min) when mean arterial pressure remained less than 70 mm Hg despite fluid challenge; study drugs were thereafter titrated to keep mean arterial pressure at 70-80 mm Hg. Three early-intervention groups (each n = 7) received selepressin, arginine vasopressin, or norepinephrine at the same initial infusion rates as for the late intervention, but already when mean arterial pressure had decreased by 10% from baseline; doses were then titrated as for the late intervention. A control group (n = 7) received saline. All animals were observed until death or for a maximum of 30 hours.

MEASUREMENTS AND MAIN RESULTS

In addition to hemodynamic and organ function assessment, plasma interleukin-6 and nitrite/nitrate levels were measured. In the late-intervention groups, selepressin delayed the decrease in mean arterial pressure and was associated with lower lung wet/dry weight ratios than in the other two groups. In the early-intervention groups, selepressin maintained mean arterial pressure and cardiac index better than arginine vasopressin or norepinephrine, slowed the increase in blood lactate levels, and was associated with less lung edema, lower cumulative fluid balance, and lower interleukin-6 and nitrite/nitrate levels. Selepressin-treated animals survived longer than the other animals.

CONCLUSIONS

In this clinically relevant model, selepressin, a selective V(1A) receptor agonist, was superior to arginine vasopressin and to norepinephrine in the treatment of septic shock, especially when administered early.

Sepsis-associated acute kidney injury: macrohemodynamic and microhemodynamic alterations in the renal circulation

Traditionally, renal ischemia has been regarded as central to the pathogenesis of sepsis-associated acute kidney injury (SA-AKI). Accordingly, hemodynamic management of SA-AKI has emphasized restoration of renal perfusion, whereas, experimentally, ischemia reperfusion models have been emphasized. However, in human beings, SA-AKI usually is accompanied by hyperdynamic circulation. Moreover, clinical and experimental evidence now suggests the importance of inflammatory mechanisms in the development of AKI and microcirculatory dysfunction more than systemic alteration in renal perfusion. In this review, we examine systemic, regional, and microcirculatory hemodynamics in SA-AKI, and attempt to rationalize the hemodynamic management of this condition.

Sepsis-Induced Acute Kidney Injury

Acute kidney injury (AKI) is a serious yet potentially reversible complication of sepsis. Several molecular mechanisms involved in the development of septic AKI have been identified. These mechanisms may be important targets in the development of future therapies. This review highlights the role of the innate immune response to sepsis and its downstream effects on kidney structure and function with special reference to the adaptive cellular response and glomerular hemodynamic changes. In addition, current evidence surrounding the management of patients with septic AKI is summarized. Finally, potential novel therapies for septic AKI are presented.