High versus low mean arterial pressures in hepatorenal syndrome: A randomized controlled pilot trial

Low Versus High Blood Pressure Targets in Critically Ill and Surgical Patients: A Systematic Review and Meta-Analysis of Randomized Controlled Trials

OBJECTIVES

Hypotension is associated with adverse outcomes in critically ill and perioperative patients. However, these assumptions are supported by observational studies. This meta-analysis of randomized controlled trials aims to compare the impact of lower versus higher blood pressure targets on mortality.

DATA SOURCES

We searched PubMed, Cochrane, and Scholar from inception to February 10, 2024.

STUDY SELECTION

Randomized trials comparing lower versus higher blood pressure targets in the management of critically ill and perioperative settings.

DATA EXTRACTION

The primary outcome was all-cause mortality at the longest follow-up available. This review was registered in the Prospective International Register of Systematic Reviews, CRD42023452928.

DATA SYNTHESIS

Of 2940 studies identified by the search string, 28 (12 in critically ill and 16 in perioperative settings) were included totaling 15,672 patients. Patients in the low blood pressure target group had lower mortality (23 studies included: 1019/7679 [13.3%] vs. 1103/7649 [14.4%]; relative risk 0.93; 95% CI, 0.87-0.99; p = 0.03; I2 = 0%). This corresponded to a 97.4% probability of any increase in mortality with a Bayesian approach. These findings were mainly driven by studies performed in the ICU setting and with treatment lasting more than 24 hours; however, the magnitude and direction of the results were similar in the majority of sensitivity analyses including the analysis restricted to low risk of bias studies. We also observed a lower rate of atrial fibrillation and fewer patients requiring transfusion in low-pressure target groups. No differences were found in the other secondary outcomes.

CONCLUSIONS

Based on pooled randomized trial evidence, a lower compared with a higher blood pressure target results in a reduction of mortality, atrial fibrillation, and transfusion requirements. Lower blood pressure targets may be beneficial but there is ongoing uncertainty. However, the present meta-analysis does not confirm previous findings and recommendations. These results might inform future guidelines and promote the study of the concept of protective hemodynamics.

High-normal versus low-normal mean arterial pressure thresholds in critically ill patients: a systematic review and meta-analysis of randomized trials

PURPOSE

Targeted blood pressure thresholds remain unclear in critically ill patients. Two prior systematic reviews have not shown differences in mortality with a high mean arterial pressure (MAP) threshold, but there have been new studies published since. Thus, we conducted an updated systematic review and meta-analysis of randomized controlled trials (RCTs) that compared the effect of a high-normal vs low-normal MAP on mortality, favourable neurologic outcome, need for renal replacement therapy, and adverse vasopressor-induced events in critically ill patients.

SOURCE

We searched six databases from inception until 1 October 2022 for RCTs of critically ill patients targeted to either a high-normal vs a low-normal MAP threshold for at least 24 hr. We assessed study quality using the revised Cochrane risk-of-bias 2 tool and the risk ratio (RR) was used as the summary measure of association. We used the Grading of Recommendations Assessment, Development, and Evaluation framework to assess the certainty of evidence.

PRINCIPAL FINDINGS

We included eight RCTs with 4,561 patients. Four trials were conducted in patients following out-of-hospital cardiac arrest, two in patients with distributive shock requiring vasopressors, one in patients with septic shock, and one in patients with hepatorenal syndrome. The pooled RRs for mortality (eight RCTs; 4,439 patients) and favourable neurologic outcome (four RCTs; 1,065 patients) were 1.06 (95% confidence interval [CI], 0.99 to 1.14; moderate certainty) and 0.99 (95% CI, 0.90 to 1.08; moderate certainty), respectively. The RR for the need for renal replacement therapy (four RCTs; 4,071 patients) was 0.97 (95% CI, 0.87 to 1.08; moderate certainty). There was no statistical between-study heterogeneity across all outcomes.

CONCLUSION

This updated systematic review and meta-analysis of RCTs found no differences in mortality, favourable neurologic outcome, or the need for renal replacement therapy between critically ill patients assigned to a high-normal vs low-normal MAP target.

STUDY REGISTRATION

PROSPERO (CRD42022307601); registered 28 February 2022.

Responsiveness to Vasoconstrictor Therapy in Hepatorenal Syndrome Type 1

Key Points

Raising the mean arterial pressure (MAP) during management of hepatorenal syndrome type 1 (HRS-1) is associated with improvement in kidney function, independently of baseline MAP or model for end-stage liver disease. Raising the MAP by 15 mm Hg or greater leads to greater reduction in serum creatinine in HRS-1. Norepinephrine use confers greater probability of improvement in kidney function in HRS-1 compared with midodrine/octreotide.

Background

Raising mean arterial pressure (MAP) during treatment of hepatorenal syndrome type 1 (HRS-1) with vasoconstrictors (VCs) is associated with renal recovery. However, the optimal MAP target and factors associated with response to VCs remain unclear.

Methods

Records from hospitalized patients with HRS-1 treated with VCs without shock were reviewed searching for those who achieved ≥5 mm Hg rise in MAP within 48 hours. We examined the relationship between the mean MAP achieved during the first 48–72 hours of VC therapy and the change in serum creatinine (sCr) up to day 14. Endpoints were >30% reduction in sCr without need for dialysis or death by day 14 (primary) or by day 30 (secondary).

Results

Seventy-seven patients with HRS-1 treated for 2–10 days with either norepinephrine (n =49) or midodrine/octreotide (n =28) were included. The median age was 52 years (interquartile range [IQR], 46–60), 40% were female, and 48% had alcoholic cirrhosis. At VC initiation, median MAP was 70 mm Hg (IQR, 66–73), and median sCr was 3.8 mg/dl (IQR, 2.6–4.9). When analyzed by tertiles of mean MAP increment (5–9, 10–14, ≥15 mm Hg), there was greater reduction in sCr with greater rise in MAP (ANOVA for trend, P < 0.0001). By multivariate logistic regression analysis, mean MAP rise during the first 48–72 hours (odds ratio [OR], 1.15 [1.02 to 1.299], P =0.025), norepinephrine as VC (OR, 5.46 [1.36 to 21.86], P =0.017), and baseline sCr [OR, 0.63 [0.41 to 0.97], P =0.034) were associated with the primary endpoint, whereas mean MAP rise during the first 48–72 hours (OR, 1.17 [1.04 to 1.33], P =0.012) and baseline sCr (OR, 0.63 [0.39 to 0.98], P =0.043) were associated with the secondary endpoint.

Conclusions

Greater magnitude of rise in MAP with VC therapy in HRS-1, lower baseline sCr, and use of norepinephrine over midodrine/octreotide are associated with kidney recovery. Targeting an increment of MAP ≥15 mm Hg may lead to favorable renal outcomes.

Hepatorenal syndrome in acute-on-chronic liver failure with acute kidney injury: more questions requiring discussion

In cirrhosis with ascites, hepatorenal syndrome (HRS) is a specific prerenal dysfunction unresponsive to fluid volume expansion. Acute-on-chronic liver failure (ACLF) comprises a group of clinical syndromes with multiple organ failure and early high mortality. There are differences in the characterization of ACLF between the Eastern and Western medical communities. Patients with ACLF and acute kidney injury (AKI) have more structural injuries, contributing to confusion in diagnosing HRS-AKI. In this review, we discuss progress in the pathogenesis, diagnosis, and management of HRS-AKI, especially in patients with ACLF. Controversy regarding HRS-AKI in ACLF and acute liver failure, hepatic carcinoma, shock, sepsis, and chronic kidney disease is also discussed. Research on the treatment of HRS-AKI with ACLF needs to be more actively pursued to improve disease prognosis.