Circulating bile is the main factor responsible for atrial natriuretic peptide release in experimental obstructive jaundice

Effect of MELD-Na score on overall survival of periampullary cancer

Periampullary cancers have a short overall survival (OS), and many prognostic factors have been studied for this purpose. They usually present with biliary obstruction, which negatively affects the liver, kidney, immune system, and cardiovascular system. This study aimed to investigate the effect of MELD-Na scores on OS in patients undergoing pancreaticoduodenectomy due to periampullary cancer. Patients who underwent pancreaticoduodenectomy due to periampullary cancer between January 2010 and January 2021 were included in the study. After applying the exclusion criteria, 80 of the 124 patients were included in the study. The demographic, laboratory, and pathologic data of the patients were analyzed retrospectively. Univariate analysis showed that MELD-Na score at admission, age-adjusted Charlson Comorbidity Index, adjuvant treatment, portal vein resection, lymphovascular invasion (LVI), T-stage, and tumor location were significantly associated with OS (p < 0.1). In multivariate analysis, MELD-Na score at admission (HR: 1.051, 95% CI [1.004-1.101]; p = 0.033), adjuvant treatment (HR: 4.717, 95% CI [2.371-9.383]; p < 0.001), LVI (HR: 2.473, 95% CI [1.355-4.515]; p = 0.003), and tumor location (HR: 2.380, 95% CI [1.274-4.445]; p = 0.007) were independent risk factors for OS. MELD-Na score, adjuvant treatment, LVI, and tumor location were independent risk factors for the OS of periampullary cancer. The MELD-Na score may be used to predict OS for patients undergoing pancreaticoduodenectomy due to periampullary cancer.

Should preoperative biliary drainage be routinely performed for obstructive jaundice with resectable tumor?

Obstructive jaundice is a common clinical manifestation of malignant lesions adjacent to extrahepatic bile duct, ampulla or pancreatic head. Animal experiments and some clinical observations have demonstrated that preoperative biliary drainage could improve liver function as well as reduce endotoxemia, thereby reducing the incidence of perioperative complications. However, a number of randomized, controlled studies have found that preoperative biliary drainage failed to improve prognosis or reduce the incidence of perioperative complications; in contrast, it might increase the incidence of complications and cause extra financial burden on patients. Thus, whether preoperative biliary drainage should be performed or not is controversial. Since clinical randomized controlled studies are more relevant in clinical setting, we believe that preoperative biliary drainage should not be routinely performed for obstructive jaundice with resectable tumors. More randomized, controlled, prospective studies should be conducted for further exploration.

Obstructive jaundice and perioperative management

The causes of obstructive jaundice are varied, but it is most commonly due to choledocholithiasis; benign strictures of the biliary tract; pancreaticobiliary malignancies; and metastatic disease. Surgery in patients with obstructive jaundice is generally considered to be associated with a higher incidence of complications and mortality. Therefore, it poses a considerable challenge to the anesthesiologist, surgeons, and the intensive care team. However, appropriate preoperative evaluation and optimization can greatly contribute to a favorable outcome for perioperative jaundiced patients. This article outlines the association between obstructive jaundice and perioperative management, and reviews the clinical and experimental studies that have contributed to our knowledge of the underlying pathophysiologic mechanisms. Pathophysiology caused by obstructive jaundice involving coagulopathies, infection, renal dysfunction, and other adverse events should be fully assessed and reversed preoperatively. The depressed cardiovascular effects of obstructive jaundice are worth noticing because it has complicated mechanisms and needs to be further explored. Alterations of anesthesia-related drugs induced by obstructive jaundice are varied and clinicians should be aware of the possible need for a decrease in the anesthetic dose. Recommendations concerning the perioperative management of the patients with obstructive jaundice including preoperative biliary drainage, anti-infection, nutrition support, coagulation reversal, cardiovascular evaluation, perioperative fluid therapy, and hemodynamic optimization should be taken.

G protein-coupled bile acid receptor 1 stimulation mediates arterial vasodilation through a K(Ca)1.1 (BK(Ca))-dependent mechanism

Bile acids (BAs) and BA receptors, including G protein-coupled bile acid receptor 1 (GPBAR1), represent novel targets for the treatment of metabolic and inflammatory disorders. However, BAs elicit myriad effects on cardiovascular function, although this has not been specifically ascribed to GPBAR1. This study was designed to test whether stimulation of GPBAR1 elicits effects on cardiovascular function that are mechanism based that can be identified in acute ex vivo and in vivo cardiovascular models, to delineate whether effects were due to pathways known to be modulated by BAs, and to establish whether a therapeutic window between in vivo cardiovascular liabilities and on-target efficacy could be defined. The results demonstrated that the infusion of three structurally diverse and selective GPBAR1 agonists produced marked reductions in vascular tone and blood pressure in dog, but not in rat, as well as reflex tachycardia and a positive inotropic response, effects that manifested in an enhanced cardiac output. Changes in cardiovascular function were unrelated to modulation of the levothyroxine/thyroxine axis and were nitric oxide independent. A direct effect on vascular tone was confirmed in dog isolated vascular rings, whereby concentration-dependent decreases in tension that were tightly correlated with reductions in vascular tone observed in vivo and were blocked by iberiotoxin. Compound concentrations in which cardiovascular effects occurred, both ex vivo and in vivo, could not be separated from those necessary for modulation of GPBAR1-mediated efficacy, resulting in project termination. These results are the first to clearly demonstrate direct and potent peripheral arterial vasodilation due to GPBAR1 stimulation in vivo through activation of large conductance Ca(2+) activated potassium channel K(Ca)1.1.

Bile acids regulate cardiovascular function

Research over the last decade has uncovered roles for bile acids (BAs) that extend beyond their traditional functions in regulating lipid digestion and cholesterol metabolism. BAs are now recognized as signaling molecules that interact with both plasma membrane and nuclear receptors. Emerging evidence indicates that by interacting with these receptors, BAs regulate their own synthesis, glucose and energy homeostasis, and other important physiological events. Herein, we provide a comprehensive review of the actions of BAs on cardiovascular function. In the heart and the systemic circulation, BAs interact with plasma membrane G-protein-coupled receptors, for example, TGR5 and muscarinic receptors, and nuclear receptors, for example, the farnesoid (FXR) and pregnane (PXR) xenobiotic receptors. BA receptors are expressed in cardiovascular tissue, however, the mechanisms underlying BA-mediated regulation of cardiovascular function remain poorly understood. BAs reduce heart rate by regulating channel conductance and calcium dynamics in sino-atrial and ventricular cardiomyocytes and regulate vascular tone via both endothelium-dependent and -independent mechanisms. End-stage liver disease, obstructive jaundice, and intrahepatic cholestasis of pregnancy are prominent conditions in which elevated serum BAs alter vascular dynamics. This review focuses on BAs as newly recognized signaling molecules that modulate cardiovascular function.

Preoperative biliary drainage in patients with obstructive jaundice: history and current status

RATIONALE

Preoperative biliary drainage (PBD) has been introduced to improve outcome after surgery in patients suffering from obstructive jaundice due to a potentially resectable proximal or distal bile duct/pancreatic head lesion. In experimental models, PBD is almost exclusively associated with beneficial results: improved liver function and nutritional status; reduction of systemic endotoxemia; cytokine release; and, as a result, an improved immune response. Mortality was significantly reduced in these animal models. Human studies show conflicting results.

FINDINGS

For distal obstruction, currently the "best-evidence" available clearly shows that routine PBD does not yield the appreciated improvement in postoperative morbidity and mortality in patients undergoing resection. Moreover, PBD harbors its own complications. However, most of the available data are outdated or suffer from methodological deficits.

CONCLUSION

The highest level of evidence for PBD to be performed in proximal obstruction, as well as over the preferred mode, is lacking but, nevertheless, assimilated in the treatment algorithm for many centers. Logistics and waiting lists, although sometimes inevitable, could be factors that might influence the decision to opt for PBD, as well as an extended diagnostic workup with laparoscopy (on indication) or scheduled preoperative chemotherapy.

Randomized clinical trial of the effect of intravenous fluid administration on hormonal and renal dysfunction in patients with obstructive jaundice undergoing endoscopic drainage

BACKGROUND

Renal dysfunction in patients with biliary obstruction is associated with extracellular water depletion. This study examined the effect of preoperative saline infusion before biliary drainage on hormonal and renal functional derangements in patients with obstructive jaundice.

METHODS

In a randomized study, 49 patients with malignant obstructive jaundice were investigated at baseline, on the day of drainage, and at 24 h, 72 h and 7 days after internal endoscopic biliary drainage. Patients were randomized to receive (n = 22) or not to receive (n = 27) 3000 ml normal saline intravenously for 24 h before drainage. Variables analysed included extracellular water volume, creatinine clearance, and serum levels of aldosterone, renin, atrial natriuretic peptide (ANP), vasopressin and albumin.

RESULTS

Preoperative saline infusion produced a rise in creatinine clearance, diuresis, ANP concentration and extracellular water volume but this did not translate into better recovery of renal function after operation. Drainage produced a fall in creatinine clearance in all patients, but hormonal and renal function had recovered by 2 days after restoration of bile flow, independently of preoperative hydration.

CONCLUSION

Fluid administration expands the extracellular water compartment before drainage but fails to improve renal function after drainage. Definitive improvement in endocrine and renal function requires the restoration of bile flow into the duodenum.

Improved cardiac function in patients with obstructive jaundice after internal biliary drainage: hemodynamic and hormonal assessment

OBJECTIVE

To investigate myocardial function in patients with obstructive jaundice before and after internal biliary drainage.

SUMMARY BACKGROUND DATA

Increased plasma levels of atrial natriuretic peptide (ANP) have been found in patients with biliary obstruction.

METHODS

Thirteen patients with newly diagnosed obstructive jaundice and no previous heart, lung, or renal disease were studied using a Swan-Ganz catheter. Hemodynamic measurements were taken before and 4 days after internal biliary drainage. Levels of ANP and brain natriuretic peptide (BNP) were obtained and liver function tests were also determined.

RESULTS

Plasma levels of ANP and BNP were increased twofold to fourfold in the basal state and declined after biliary drainage. Independent variables predicting left ventricular systolic work were total bilirubin concentrations, duration of jaundice, and BNP. In addition, bilirubin concentrations correlated with pulmonary vascular resistance, mean arterial pulmonary pressure, and right ventricular systolic work. Internal biliary drainage resulted in an improvement in left ventricular systolic work. A correlation was found between decreasing ANP concentrations and increasing cardiac output.

CONCLUSIONS

Increased plasma levels of natriuretic peptides in patients with obstructive jaundice may reflect a subclinical myocardial dysfunction correlating with the degree of jaundice. After internal biliary drainage, there is a measurable improvement of cardiac function.

An improved rat model of obstructive jaundice and its reversal by internal and external drainage

BACKGROUND

A simple and reproducible rat model that allows studies of the reversal of obstructive jaundice (OJ) by internal (ID) and external (ED) drainage is not available at present.

METHODS

OJ was induced in rats by double ligation and division of the common bile duct. To minimize tissue handling and dissection the duodenum was extracted with a ophthalmic muscle hook and the common bile duct isolated using very fine forceps. One week after bile duct ligation, ID was accomplished by implanting a length of infant feeding tube between the dilated bile duct and the duodenum. ED was achieved by placing a PVC tube into the dilated bile duct and exteriorizing the other end at the nape of the neck.

RESULTS

Minimal adhesions were found around the dilated common bile duct, which made relaparotomy for drainage easy. Alanine transaminase, total bilirubin, alkaline phosphatase, and gamma-glutamyltransferase were significantly raised after bile duct ligation. All parameters returned to control levels after ID for 7 days. In the ED group plasma albumin was significantly decreased and alkaline phosphatase remained marginally elevated.

CONCLUSIONS

We have developed a simple and reproducible rat model that allows for the study of reversal of OJ by ID or ED. We also demonstrated that ID is superior to ED in reversing impaired liver function in OJ.

The natriuretic peptides: universal volume controllers

Since the discovery of the natriuretic effect of atrial natriuretic peptide (ANP), a family of other natriuretic peptides similar to ANP were isolated, including atriopeptin, vessel dilator, long-acting natriuretic peptide, urodilatin, and brain natriuretic peptide (BNP) to name a few. ANP was noted to possess natriuretic and diuretic properties that controlled increases in intravascular volume. ANP was also found to be elevated in conditions of increased intraocular pressure and biliary obstruction. BNP was found to be elevated in conditions of increased intracranial pressure, pointing towards its role in controlling cerebrospinal fluid volume. While at the cellular level, ANP controlled individual cell size. This makes the natriuretic peptides not only controllers of intravascular volume, but also modulators of a myriad of cavity volumes down to the control of individual cell volume.

Renal effects of experimental obstructive jaundice: morphological and functional assessment

BACKGROUND

The pathophysiology of renal impairments occurring in obstructive jaundice has been extensively studied, but the underlying mechanism of these derangements remains unclear. The aim of the present study was to investigate the time-related morphological and functional changes occurring in the kidneys of rats undergoing obstructive jaundice.

METHODS

Histological examination, renal function assessment and determination of (Na + K)-ATPase activity were performed in the kidneys of rats 7, 14, and 21 days following bile duct ligation (BDL) or sham operation (sham).

RESULTS

Glomerular filtration rate was unaffected by BDL throughout the period of the study. Tubular effects occurred at days 7 and 14, being more marked at day 7, and consisted of an increase of about twice in the fractional excretion of sodium and chloride, paralleled by a decreased proximal and distal tubular reabsorption of sodium of about 50 and 40%, respectively. Natriuresis was consistent with augmentation of osmolar clearance but it was not associated with changes in the activity of renal (Na+ + K+)-ATPase. The ability to dilute urine was impaired at days 14 and 21 after BDL. Additionally, these effects were accompanied by decreased tubulointerstitial fibrosis and vasodilation of inner medullary capillaries. At day 21, the parameters of tubular function in BDL and sham groups were not significantly different.

CONCLUSIONS

These data support the view that raised natriuresis taking place in the initial 2 weeks following BDL is due mainly to tubular effects. The contribution of hemodynamic, paracrine and humoral mediators is discussed.