Renal effects of a urodilatin infusion in patients with liver cirrhosis, with and without ascites

Effects and safety of natriuretic peptides as treatment of cirrhotic ascites: A systematic review and meta-analysis

BACKGROUND

Natriuretic peptides are involved in the cascade of pathophysiological events occurring in liver cirrhosis, counterbalancing vasoconstriction and anti-natriuretic factors. The effects of natriuretic peptides as treatment of cirrhotic ascites have been investigated only in small studies, and definitive results are lacking.

AIM

To examine the effects and safety of natriuretic peptides in cirrhosis patients with ascites.

METHODS

We searched MEDLINE, Web of Science, Scopus, Cochrane Library and Embase for all available studies applying intravenous administration of any natriuretic peptide to patients suffering from cirrhotic ascites. Inclusion was not limited by treatment duration or dose, or by follow-up duration. Both randomised controlled trials and non-randomised studies were eligible for inclusion. The primary outcome was change in renal sodium excretion. Secondary outcomes included safety measures and changes in renal water excretion, plasma aldosterone concentration, and plasma renin activity.

RESULTS

Twenty-two studies were included. Atrial natriuretic peptide (ANP) was the only intensively studied treatment. Sodium excretion increased in response to continuous ANP infusion and was more pronounced when infusion rates of > 30 ng/kg/min were administered compared with ≤ 30 ng/kg/min (P < 0.01). Moreover, natriuresis was significantly higher in study subgroups with mild/moderate ascites compared with moderate/severe and refractory ascites (P < 0.01). ANP infusions increased renal water excretion, although without reaching a statistically significant dose-response gradient. Plasma aldosterone concentration and plasma renin activity were significantly lower at baseline in study subgroups achieving a negative sodium balance in response to an ANP administration compared with treatment non-responders (P < 0.01). Blood pressure decreases occurred less frequently when ANP doses ≤ 30 ng/kg/min were applied. The quality of evidence for a natriuretic response to ANP was low, mainly due to small sample sizes and considerable between-study heterogeneity. Data were sparse for the other natriuretic peptides; B-type natriuretic peptide and urodilatin.

CONCLUSION

Intravenous ANP infusions increase sodium excretion in patients with cirrhotic ascites. Continuous infusion rates > 30 ng/kg/min are the most effective. However, safety increases with infusion rates ≤ 30 ng/kg/min.

Treatment of hepatorenal syndrome

Hepatorenal syndrome (HRS) is a type of renal failure that occurs in patients with advanced cirrhosis. It is a result of splanchnic arterial vasodilation, renal vasoconstriction, reduced effective arterial volume, and potentially reduced cardiac output. Often, HRS is a fatal complication, and the only definitive treatment currently available is liver or liver-kidney transplantation. A number of other treatment modalities have been tested for the management of HRS, but most evidence is derived from small noncontrolled studies. The primary role of these treatment options is to provide a bridge to liver transplantation. Treatment may also provide acute reversal of renal failure and some symptomatic relief, but relapse is a common occurrence. The best therapeutic options appear to be those that reverse portal hypertension, splanchnic vasodilation, and/or renal vasoconstriction. Vasopressin analogs, particularly terlipressin, have emerged as the preferred pharmacologic therapies for management of HRS. Albumin is an appropriate adjunctive therapy to terlipressin and can be used to prevent HRS in patients with spontaneous bacterial peritonitis. Transjugular intrahepatic portosystemic shunt may provide a surgical option for qualified patients with HRS. Octreotide is ineffective as monotherapy but may be used as adjunctive therapy to other vasoactive agents. Dopamine agonists, endothelin antagonists, natriuretic peptides, and nitric oxide synthase inhibitors have not been effective for reversing HRS. Artificial hepatic support therapies have demonstrated the ability to improve laboratory abnormalities in patients with HRS, but their effect on clinical outcomes has not been determined. The role of renal replacement therapies or the newer artificial hepatic support therapies need further evaluation before they can be routinely recommended.

Renal effects of urodilatin in healthy subjects are independent of blockade of the cyclooxygenase and angiotensin II receptor

OBJECTIVE

Little is known about the role of the renin-angiotensin-aldosterone system and the renal prostaglandins in modulating the renal vasoconstrictive and natriuretic effects of synthetic urodilatin (URO) in healthy humans.

MATERIAL AND METHODS

Twelve volunteers were pretreated in a randomized, single-blind, crossover study with losartan 50 mg a day or placebo for 5 days. Another 12 healthy subjects received indomethacin 25 mg three times a day or placebo for 4 days and a single dose on day 5. All subjects received a URO infusion (15 ng kg(-1) min(-1)) on day 5. Radioactive tracers and the lithium clearance technique were used.

RESULTS

The effective renal plasma flow (ERPF) decreased significantly during URO infusion: losartan pretreatment 573+/-63 to 461+/-76 mL/min versus placebo 540+/-89 to 432+/-90 mL/min. The urinary sodium excretion rate (UNa) increased significantly during URO infusion: losartan 335+/-115 to 502+/-134 umol/min (micromol/min) (UNa) versus placebo 386+/-142 to 476+/-137 umol/min (micromol/min) (UNa). In the indomethacin pretreated subjects, ERPF decreased significantly from 530+/-109 to 446+/-55 mL/min versus 533+/-89 to 449+/-69 mL/min in the placebo group. UNa increased significantly from 395+/-142 to 768+/-254 umol/min (micromol/min) (UNa) in the indomethacin group versus 282+/-117 to 552+/-242 umol/min (micromol/min) (UNa) in placebo.

CONCLUSION

The renal vasoconstrictive and natriuretic effects of synthetic URO are not modified by sustained inhibition of the angiotensin II receptor or the cyclooxygenase in man in a sodium replete state.

Effects of urodilatin on natriuresis in cirrhosis patients with sodium retention

BACKGROUND

Sodium retention and ascites are serious clinical problems in cirrhosis. Urodilatin (URO) is a peptide with paracrine effects in decreasing sodium reabsorption in the distal nephron. Our aim was to investigate the renal potency of synthetic URO on urine sodium excretion in cirrhosis patients with sodium retention and ascites.

METHODS

Seven cirrhosis patients with diuretics-resistant sodium retention received a short-term (90 min) infusion of URO in a single-blind, placebo-controlled cross-over study. In the basal state after rehydration the patients had urine sodium excretion < 50 mmol/24 h.

RESULTS

URO transiently increased urine sodium excretion from 22 +/- 16 micromol/min (mean +/- SD) to 78 +/- 41 mumol/min (P < 0.05) and there was no effect of placebo (29 +/- 14 to 44 +/- 32). The increase of URO's second messenger after the receptor, cGMP, was normal. URO had no effect on urine flow or on blood pressure. Most of the patients had highly elevated plasma levels of renin, angiotensin II and aldosterone and URO did not change these.

CONCLUSION

The short-term low-dose URO infusion increased the sodium excretion of the patients. The increase was small but systematic and potentially clinically important for such patients. The small response contrasts the preserved responsiveness of the URO receptors. The markedly activated systemic pressor hormones in cirrhosis evidently antagonized the local tubular effects of URO.

[Hepatorenal syndrome]

Hepatorenal syndrome (HRS) is defined as the development of renal insufficiency in chronic liver disease with portal hypertension when other causes of functional renal failure are excluded. Incidence in patients with refractory ascites is 8%, with an overall incidence of renal failure in end stage liver disease being 75%. HRS is predictive for the prognosis of end stage liver failure but its pathogenesis is complex and currently not fully understood.

Clinical outcome after cardiac operations in patients with cirrhosis

BACKGROUND

To evaluate the clinical outcome after cardiac operations in patients with cirrhosis, a retrospective study was undertaken.

METHODS

Between 1989 and 2003, 18 patients with cirrhosis who underwent cardiac operations were identified. Their preoperative status and postoperative clinical results were assessed.

RESULTS

Ten patients were classified as having Child-Pugh class A cirrhosis, 7 as having class B cirrhosis, and 1 as having class C cirrhosis. Fifteen of 18 patients underwent cardiac surgery using cardiopulmonary bypass, and the remaining 3 patients with class B cirrhosis received coronary artery bypass grafting without cardiopulmonary bypass. In patients undergoing cardiopulmonary bypass, 60% of those with class A cirrhosis and 100% of those with class B cirrhosis and class C cirrhosis had postoperative major complications, including infection, respiratory failure, renal failure, bleeding, and gastrointestinal disorder. One of 3 patients (33%) with class B cirrhosis undergoing coronary artery bypass grafting without cardiopulmonary bypass had major complications. The overall postoperative mortality rate was 17%. Hospital mortality of patients with class A cirrhosis, class B cirrhosis, and class C cirrhosis undergoing cardiopulmonary bypass was 0%, 50%, and 100%, respectively. None of 3 patients with class B cirrhosis undergoing coronary artery bypass grafting without cardiopulmonary bypass died in this study.

CONCLUSIONS

Although the incidence of major complications was high, patients with Child-Pugh class A cirrhosis tolerated cardiac surgery satisfactorily. Patients with more advanced cirrhosis, however, may not be suitable for elective cardiac operations with cardiopulmonary bypass. Although our results are not conclusive, coronary artery bypass grafting without cardiopulmonary bypass can be an alternative therapeutic strategy for patients with advanced cirrhosis requiring surgical revascularization.