Hypophosphatemia after live donor right hepatectomy

The Association Between Low Preoperative Phosphate Levels and Postliver Surgery Outcomes-A Single Center Experience

INTRODUCTION

Previous research has demonstrated the impact of postoperative phosphate levels on liver regeneration and outcomes after liver resection surgeries, a potential predictor for regenerative success and liver failure. However, little is known about the association between low preoperative serum phosphate levels and outcomes in liver resections.

METHODS

We performed a retrospective analysis of liver resections performed at our institution. Patients were categorized based on preoperative phosphate levels (low versus normal). Our primary outcome measure was posthepatectomy liver failure.

RESULTS

A total of 265 cases met the study criteria. 71 patients (26.7%) had low preoperative phosphate levels. The incidence of posthepatectomy liver failure was higher in the low preoperative phosphate group (19.2% versus 12.4%). However, after propensity score matching, rates of posthepatectomy liver failure were similar between low and normal preoperative phosphate cohorts (13% versus 14%, P = 0.83).

CONCLUSIONS

Low preoperative phosphate levels were not associated with worse postoperative outcomes in this study. Further studies are warranted to investigate this association and its relevance as a clinical prognostic factor for postoperative liver failure.

Hypophosphatemia as a prognostic tool for post-hepatectomy liver failure: A systematic review

BACKGROUND

Post-hepatectomy liver failure (PHLF) is one of the main causes of postoperative mortality and is challenging to predict early in patients after liver resection. Some studies suggest that the postoperative serum phosphorus might predict outcomes in these patients.

AIM

To perform a systematic literature review on hypophosphatemia and evaluate it as a prognostic factor for PHLF and overall morbidity.

METHODS

This systematic review was performed according to preferred reporting items for systematic reviews and meta-analyses statement. A study protocol for the review was registered in the International Prospective Register of Systematic Reviews database. PubMed, Cochrane and Lippincott Williams & Wilkins databases were systematically searched up to March 31, 2022 for studies analyzing postoperative hypophosphatemia as a prognostic factor for PHLF, overall postoperative morbidity and liver regeneration. The quality assessment of the included cohort studies was performed according to the Newcastle-Ottawa Scale.

RESULTS

After final assessment, nine studies (eight retrospective and one prospective cohort study) with 1677 patients were included in the systematic review. All selected studies scored ≥ 6 points according to the Newcastle-Ottawa Scale. Cutoff values of hypophosphatemia varied from < 1 mg/dL to ≤ 2.5 mg/dL in selected studies with ≤ 2.5 mg/dL being the most used defining value. Five studies analyzed PHLF, while the remaining four analyzed overall complications as a main outcome associated with hypophosphatemia. Only two of the selected studies analyzed postoperative liver regeneration, with reported better postoperative liver regeneration in cases of postoperative hypophosphatemia. In three studies hypophosphatemia was associated with better postoperative outcomes, while six studies revealed hypophosphatemia as a predictive factor for worse patient outcomes.

CONCLUSION

Changes of the postoperative serum phosphorus level might be useful for predicting outcomes after liver resection. However, routine measurement of perioperative serum phosphorus levels remains questionable and should be evaluated individually.

Postoperative Hypophosphatemia as a Prognostic Factor for Postoperative Pancreatic Fistula: A Systematic Review

Background and Objectives: Postoperative pancreatic fistula (POPF) is one of the most challenging complications after pancreatic resections, associated with prolonged hospital stay and high mortality. Early identification of pancreatic fistula is necessary for the treatment to be effective. Several prognostic factors have been identified, although it is unclear which one is the most crucial. Some studies show that post-pancreatectomy hypophosphatemia may be associated with the development of POPF. The aim of this systematic review was to determine whether postoperative hypophosphatemia can be used as a prognostic factor for postoperative pancreatic fistula. Materials and Methods: The systematic literature review was performed according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses recommendations (PRISMA) and was registered in the International Prospective Register of Systematic Reviews (PROSPERO). The PubMed, ScienceDirect, and Web of Science databases were systematically searched up to the 31st of January 2022 for studies analyzing postoperative hypophosphatemia as a prognostic factor for POPF. Data including study characteristics, patient characteristics, operation type, definitions of postoperative hypophosphatemia and postoperative pancreatic fistula were extracted. Results: Initially, 149 articles were retrieved. After screening and final assessment, 3 retrospective studies with 2893 patients were included in this review. An association between postoperative hypophosphatemia and POPF was found in all included studies. Patients undergoing distal pancreatectomy were more likely to develop severe hypophosphatemia compared to patients undergoing proximal pancreatectomy. Serum phosphate levels on postoperative day 4 (POD 4) and postoperative day 5 (POD 5) remained significantly lower in patients who developed leak-related complications showing a slower recovery of hypophosphatemia from postoperative day 3 (POD 3) through postoperative day 7 (POD 7). Moreover, body mass index (BMI) higher than 30 kg/m², soft pancreatic tissue, abnormal white blood cell count on postoperative day 3 (POD 3), and shorter surgery time were associated with leak-related complications (LRC) and lower phosphate levels. Conclusions: Early postoperative hypophosphatemia might be used as a prognostic biomarker for early identification of postoperative pancreatic fistula. However, more studies are needed to better identify significant cut-off levels of postoperative hypophosphatemia and development of hypophosphatemia in the postoperative period.

Hypophosphatemia in acute liver failure of a broad range of etiologies is associated with phosphaturia without kidney damage or phosphatonin elevation

Hypophosphatemia is a common and dangerous complication of acute liver failure (ALF) of various etiologies. While various mechanisms for ALF-associated hypophosphatemia have been proposed including high phosphate uptake into regenerating hepatocytes, acetaminophen (APAP)-associated hypophosphatemia was linked to renal phosphate wasting, and APAP-induced renal tubular injury was proposed as underlying mechanism. We studied 30 normophosphatemic and 46 hypophosphatemic (serum phosphate < 2.5 mg/dL) patients from the Acute Liver Failure Study Group registry with APAP- or non-APAP-induced ALF. Since kidney injury affects phosphate excretion, patients with elevated serum creatinine (>1.2 mg/dL) were excluded. Maximal amount of renal tubular phosphate reabsorption per filtered volume (TmP/GFR) was calculated from simultaneous serum and urine phosphate and creatinine levels to assess renal phosphate handling. Instead of enhanced renal phosphate reabsorption as would be expected during hypophosphatemia of non-renal causes, serum phosphate was positively correlated with TmP/GFR in both APAP- and non-APAP-induced ALF patients (R2 = 0.66 and 0.46, respectively; both P < 0.0001), indicating renal phosphate wasting. Surprisingly, there was no evidence of kidney damage based on urinary markers including neutrophil gelatinase-associated lipocalin and cystatin C even in the APAP group. Additionally, there was no evidence that the known serum phosphatonins parathyroid hormone, fibroblast growth factor 23, and α-Klotho contribute to the observed hypophosphatemia. We conclude that the observed hypophosphatemia with renal phosphate wasting in both APAP- and non-APAP-mediated ALF is likely the result of renal tubular phosphate leak from yet-to-be identified factor(s) with no evidence for proximal tubular damage or contribution of known phosphatonins.

Hungry Bone Syndrome After Living Donor Liver Transplant for Biliary Atresia

Hungry bone syndrome is a rare but potentially lethal complication that is characterized by rapid, severe, long-lasting hypocalcemia and hypophosphatemia secondary to increased bone metabolism. We present a case of hungry bone syndrome after living donor liver transplant for biliary atresia. Following a failed Kasai procedure for biliary atresia, a 5-month-old boy underwent living donor liver transplant with reduced left lateral lobe from his father. Despite the oral administration of alfacalcidol, the patient exhibited severe craniotabes before the surgery. He developed severe hypocalcemia and hypophosphatemia im-mediately after liver transplant and required supplementation of calcium and phosphorus for 1 month thereafter. After serum levels of calcium and phosphate had normalized, there was a rapid increase in the serum bone-type alkaline phosphatase level, and the craniotabes subsided remarkably. To our knowledge, this is the world's first reported case of hungry bone syndrome after liver transplant for cholestatic cirrhosis. It underscores the importance of strict nutritional and electrolyte management in the perioperative period. A prompt diagnosis and correction of hungry bone syndrome are imperative to prevent the associated significant morbidity and mortality.

Implications of Postpancreatectomy Hypophosphatemia

BACKGROUND

Electrolyte abnormalities are commonly found after major abdominal surgery for malignancy. We hypothesized that the severity of hypophosphatemia developed in pancreatectomy patients would be associated with the incidence of complications postoperatively.

METHODS

A retrospective analysis of an institutional database was conducted for all pancreatic resections (2009-2017). Patient charts were reviewed for demographics, clinicopathologic factors, and perioperative outcomes.

RESULTS

In a cohort of 283 pancreatectomy patients, 107 (37.8%) and 134 (47.3%) developed mild (2.0-2.5 mg/dL) and moderate/severe hypophosphatemia (<2.0 mg/dL), respectively. Nadir serum phosphate levels were shown to occur on postoperative day (POD) 2 for patients without complications and POD3 for patients who had at least 1 complication. Patients who developed severe hypophosphatemia were significantly more likely to suffer fistula-related complications (P = .0401).

CONCLUSIONS

Assessing the severity and timing of postpancreatectomy hypophosphatemia presents an opportunity for early detection of impending fistula-related complications.

Clinical utility of postoperative phosphate recovery profiles to predict liver insufficiency after living donor hepatectomy

BACKGROUND

Living donor hepatectomy (LDH) is associated with significant postoperative hypophosphatemia.

METHODS

From January 1997 through July 2017, we performed 176 LDH and compared donors who developed liver insufficiency (LI) to those that did not within 30 days of LDH. Using smoothing splines, we constructed a mixed-effects model and assessed receiver operating characteristic curves.

RESULTS

Of the 176 donors, 161 were included in our study and 10 (6.2%) developed LI. The cohorts differed in minimum observed phosphate levels (1.77 mg/dL, LI cohort; 2.01 mg/dL No LI cohort) at a median nadir of 1.6 days (38 h) postoperatively (p = 0.003). In the ROC analysis, intraoperative time and postoperative phosphate levels best predicted LI (sensitivity, 90%; specificity, 55.6%).

CONCLUSION

Mean postoperative phosphate profiles differ significantly between those patients who develop LI and those who do not in the first 38 h after LDH.

Hypophosphatemia and recovery of post-hepatectomy liver insufficiency

BACKGROUND

Hypophosphatemia (HP) is frequent following liver resection, and thought to represent use of phosphate during liver regeneration. We sought to evaluate the association of post-hepatectomy HP with liver insufficiency and recovery.

METHODS

Liver resections were retrospectively reviewed from 2009 to 2012 at a single institution. We explored the relationship between HP (defined as serum phosphate ≤0.65 mmol/L), occurrence of initial liver insufficiency (ILI) [bilirubin >50 µmol/L, international normalized ratio (INR) >1.7 within 72 hours of surgery] and in-hospital recovery of ILI. Secondary outcomes included 30-day post-operative major morbidity (Clavien grade 3 and 4 complications), mortality, and re-admission.

RESULTS

Among 402 patients, 223 (55.5%) experienced HP and 64 (15.9%) met our definition of ILI, of which 53 (82.8%) recovered. Length of stay, 30-day post-operative major morbidity, mortality, and re-admission were similar between patients with and without HP. Among patients with ILI, 44 (68.8%) experienced HP. Following ILI, patients with HP recovered more often than those with NP (90.9% vs. 65.0%; P=0.03).

CONCLUSIONS

In patients who experience post-hepatectomy ILI, HP is associated with improved recovery, potentially indicating more efficient liver regeneration. Further studies should explore the usefulness of post-hepatectomy HP as an early prognostic factor of recovery from ILI.

Phosphate homeostasis and disorders

Recent studies of inherited disorders of phosphate metabolism have shed new light on the understanding of phosphate metabolism. Phosphate has important functions in the body and several mechanisms have evolved to regulate phosphate balance including vitamin D, parathyroid hormone and phosphatonins such as fibroblast growth factor-23 (FGF23). Disorders of phosphate homeostasis leading to hypo- and hyperphosphataemia are common and have clinical and biochemical consequences. Notably, recent studies have linked hyperphosphataemia with an increased risk of cardiovascular disease. This review outlines the recent advances in the understanding of phosphate homeostasis and describes the causes, investigation and management of hypo- and hyperphosphataemia.

Hypophosphataemia after major hepatectomy and the risk of post-operative hepatic insufficiency and mortality: an analysis of 719 patients

BACKGROUND

Hypophosphataemia after a hepatectomy suggests hepatic regeneration. It was hypothesized that the absence of hypophosphataemia is associated with post-operative hepatic insufficiency (PHI) and complications.

METHODS

Patients who underwent a major hepatectomy from 2000-2012 at a single institution were identified. Post-operative serum phosphorus levels were assessed. Primary outcomes were PHI (peak bilirubin >7 mg/dl), major complications, and 30- and 90-day mortality.

RESULTS

Seven hundred and nineteen out of 749 patients had post-operative phosphorus levels available. PHI and major complications occurred in 63 (8.8%) and 169 (23.5%) patients, respectively. Thirty- and 90-day mortality were 4.0% and 5.4%, respectively. The median phosphorus level on post-operative-day (POD) 2 was 2.2 mg/dl; 231 patients (32.1%) had phosphorus >2.4 on POD2. Patients with POD2 phosphorus >2.4 had a significantly higher incidence of PHI, major complications and mortality. On multivariate analysis, POD2 phosphorus >2.4 remained a significant risk factor for PHI [(hazard ratio HR):1.78; 95% confidence interval (CI):1.02-3.17; P = 0.048], major complications (HR:1.57; 95%CI:1.02-2.47; P = 0.049), 30-day mortality (HR:2.70; 95%CI:1.08-6.76; P = 0.034) and 90-day mortality (HR:2.51; 95%CI:1.03-6.15; P = 0.044). Similarly, patients whose phosphorus level reached nadir after POD3 had higher PHI, major complications and mortality.

CONCLUSION

Elevated POD2 phosphorus levels >2.4 mg/dl and a delayed nadir in phosphorus beyond POD3 are associated with increased post-operative hepatic insufficiency, major complications and early mortality. Failure to develop hypophosphataemia within 72 h after a major hepatectomy may reflect insufficient liver remnant regeneration.

Systematic review of pathophysiological changes following hepatic resection

OBJECTIVES

Major hepatic resection is now performed frequently and with relative safety, but is accompanied by significant pathophysiological changes. The aim of this review is to describe these changes along with interventions that may help reduce the risk for adverse outcomes after major hepatic resection.

METHODS

The MEDLINE, EMBASE and CENTRAL databases were searched for relevant literature published from January 2000 to December 2011. Broad subject headings were 'hepatectomy/', 'liver function/', 'liver failure/' and 'physiology/'.

RESULTS

Predictable changes in blood biochemistry and coagulation occur following major hepatic resection and alterations from the expected path indicate a complicated course. Susceptibility to sepsis, functional renal impairment, and altered energy metabolism are important sequelae of post-resection liver failure.

CONCLUSIONS

The pathophysiology of post-resection liver failure is difficult to reverse and thus strategies aimed at prevention are key to reducing morbidity and mortality after liver surgery.

Prediction of newly developed acute renal failure using serum phosphorus concentrations after living-donor liver transplantation

OBJECTIVE

This retrospective study investigated the predictive role of serum phosphorus concentration for acute renal failure (ARF), defined by the Risk Injury Failure Loss End-stage kidney disease (RIFLE) criteria, after living-donor liver transplantation (LDLT).

METHODS

Perioperative factors, including serum phosphorus concentrations, in LDLT recipients without pre-existing renal dysfunction were retrospectively analysed and compared between patients with or without post-LDLT ARF.

RESULTS

A total of 45 patients out of 350 (12.9%) met the RIFLE ARF criteria and experienced significantly higher postoperative mortality, longer intensive care unit stay and more frequent graft dysfunction than those patients without post-LDLT ARF. Multivariate logistic regression analyses showed that a serum phosphorus concentration ≥ 4.5 mg/dl on postoperative day 1 (relative risk [RR] 5.31; 95% confidence interval [CI] 2.56, 11.03), a preoperative model for end-stage liver disease score 20 points (RR 4.17, 95% CI 2.04, 8.52), and packed red blood cell transfusion 10 units (RR 2.55, 95% CI 1.13, 5.88) were independent risk factors for post-LDLT ARF.

CONCLUSIONS

Hyperphosphataemia on postoperative day 1 could be an early and simple indicator of ARF occurrence after LDLT.

Evaluation outcomes of donors in living donor liver transplantation: a single-center analysis of 132 donors

BACKGROUND

Donor safety has always been a major concern, and potential risk to the donor must be balanced against recipient benefit. However, lack of a standardized and uniform evaluation of perioperative complications is a serious limitation of the evaluation of donor morbidity. This study was designed to evaluate the outcomes of donors in adult living donor liver transplantation (LDLT) using the newer Clavien classification system in a single center in China.

METHODS

We prospectively analyzed the outcomes of 132 consecutive living liver donors from 2005 to 2008 using the newer Clavien classification system. The preoperative, intraoperative and postoperative data of the donors were collected and analyzed. Ordinal regression was used to analyze the ordered grades of complications.

RESULTS

Ninety-four (71.2%) of the donors developed postoperative complications of grade I (n=45, 34.1%), grade II (n=39, 29.5%) and grade III (n=10, 7.6%). There was no death or grade IV morbidity. Hepatic functional impairment and pleural effusion were the most frequent morbidities for living donors. Fifty-three donors (40.1%) developed hepatic functional impairment of grade I (n=40, 31.1%) and grade II (n=13, 10.0%). The ICU stay (7.8+/-1.8 days) and length of hospital stay (17.7+/-4.6 days) were significantly longer in donors with grade III than others. Furthermore, ordinal logistic regression revealed that donor's older age (>40 years) and right hepatectomy were associated with morbidity. In addition, only preoperative total bilirubin (within the normal range) and postoperative nadir serum phosphorus were independently associated with hepatic functional impairment. The receiver operator characteristic curve revealed that preoperative total bilirubin >18.0 μmol/L and postoperative nadir of serum phosphorus <1 mg/dL may lead to more severe hepatic functional impairment.

CONCLUSIONS

Despite the fact that donors are relatively safe to undergo hepatectomy, many living donors still experience postoperative morbidity. Meticulous technical and preoperative donor evaluation and treatment are sure to reduce the incidence of complications.