Alessandra Brocca

Cardio-Pulmonary-Renal Interactions: A Multidisciplinary Approach

Over the past decade, science has greatly advanced our understanding of interdependent feedback mechanisms involving the heart, lung, and kidney. Organ injury is the consequence of maladaptive neurohormonal activation, oxidative stress, abnormal immune cell signaling, and a host of other mechanisms that precipitate adverse functional and structural changes. The presentation of interorgan crosstalk may include an acute, chronic, or acute on chronic timeframe. We review the current, state-of-the-art understanding of cardio-pulmonary-renal interactions and their related pathophysiology, perpetuating nature, and cycles of increased susceptibility and reciprocal progression. To this end, we present a multidisciplinary approach to frame the diverse spectrum of published observations on the topic. Assessment of organ functional reserve and use of biomarkers are valuable clinical strategies to screen and detect disease, assist in diagnosis, assess prognosis, and predict recovery or progression to chronic disease.

Cardiac surgery-associated acute kidney injury.

Cardiac surgery-associated acute kidney injury (CSA-AKI) is a common and serious postoperative complication of cardiac surgery requiring cardiopulmonary bypass (CPB), and it is the second most common cause of AKI in the intensive care unit. Although the complication has been associated with the use of CPB, the etiology is likely multifactorial and related to intraoperative and early postoperative management including pharmacologic therapy. To date, very little evidence from randomized trials supporting specific interventions to protect from or prevent AKI in broad cardiac surgery populations has been found. The definition of AKI employed by investigators influences not only the incidence of CSA-AKI, but also the identification of risk variables. The advent of novel biomarkers of kidney injury has the potential to facilitate the subclinical diagnosis of CSA-AKI, the assessment of its severity and prognosis, and the early institution of interventions to prevent or reduce kidney damage. Further studies are needed to determine how to optimize cardiac surgical procedures, CPB parameters, and intraoperative and early postoperative blood pressure and renal blood flow to reduce the risk of CSA-AKI. No pharmacologic strategy has demonstrated clear efficacy in the prevention of CSA-AKI; however, some agents, such as the natriuretic peptide nesiritide and the dopamine agonist fenoldopam, have shown promising results in renoprotection. It remains unclear whether CSA-AKI patients can benefit from the early institution of such pharmacologic agents or the early initiation of renal replacement therapy.

Optimizing a kidney stress test to evaluate renal functional reserve.

BACKGROUND Renal function reserve (RFR) describes the capacity of the kidney to increase glomerular filtration rate (GFR) in response to physiological or pathological stimuli. The scope of our study was to evaluate the optimal level of stimulation using different doses of protein load (PL) for a standard renal stress test (RST). METHODS 18 young healthy individuals were given sessions of PL with 1 and 2 g/kg body weight. Endogenous creatinine clearance was calculated. Baseline GFR (bGFR) and stress GFR (sGFR) (post-PL) were obtained; RFR is the difference between stress and baseline GFR. A p-value < 0.05 was considered statistically significant. RESULTS Mean bGFR was 107.97 ± 12.33 mL/min/1.73m2. sGFR with 1 and 2 g PL were significantly higher than bGFR in all subjects. The sGFR after 2 g PL (141.75 ± 19.90 mL/min/1.73m2) was not statistically different from the sGFR after 1 g PL (142.37 ± 22.35 mL/min/1.73m2). sGFR and therefore RFR were independent from the value of bGFR. CONCLUSIONS We found no difference between 1 and 2 g/kg body weight PL to elicit sGFR. RST may be useful to predict susceptibility and risk of developing acute kidney injury and/or progression to chronic kidney disease. RST uncovers the possible loss of renal functional mass when this condition is not manifested clinically. Further studies are needed to set this hypothesis.

Oxidative stress: dual pathway induction in cardiorenal syndrome type 1 pathogenesis.

Cardiorenal Syndrome Type 1 (Type 1) is a specific condition which is characterized by a rapid worsening of cardiac function leading to acute kidney injury (AKI). Even though its pathophysiology is complex and not still completely understood, oxidative stress seems to play a pivotal role. In this study, we examined the putative role of oxidative stress in the pathogenesis of CRS Type 1. Twenty-three patients with acute heart failure (AHF) were included in the study. Subsequently, 11 patients who developed AKI due to AHF were classified as CRS Type 1. Quantitative determinations for IL-6, myeloperoxidase (MPO), nitric oxide (NO), copper/zinc superoxide dismutase (Cu/ZnSOD), and endogenous peroxidase activity (EPA) were performed. CRS Type 1 patients displayed significant augmentation in circulating ROS and RNS, as well as expression of IL-6. Quantitative analysis of all oxidative stress markers showed significantly lower oxidative stress levels in controls and AHF compared to CRS Type 1 patients (P < 0.05). This pilot study demonstrates the significantly heightened presence of dual oxidative stress pathway induction in CRS Type 1 compared to AHF patients. Our findings indicate that oxidative stress is a potential therapeutic target, as it promotes inflammation by ROS/RNS-linked pathogenesis.

The Hemodynamic and Nonhemodynamic Crosstalk in Cardiorenal Syndrome Type 1

The organ crosstalk can be defined as the complex biological communication and feedback between distant organs mediated via cellular, molecular, neural, endocrine and paracrine factors. In the normal state, this crosstalk helps to maintain homeostasis and optimal functioning of the human body. However, during disease states this very crosstalk can carry over the influence of the diseased organ to initiate and perpetuate structural and functional dysfunction in the other organs. Heart performance and kidney function are intimately interconnected, and the communication between these organs occurs through a variety of bidirectional pathways. The cardiorenal syndrome (CRS) is defined as a complex pathophysiological disorder of the heart and the kidneys whereby acute or chronic dysfunction in one organ may induce acute or chronic dysfunction in the other organ. In particular, CRS type 1 is characterized by a rapid worsening of the cardiac function leading to acute kidney injury. This clinical condition requires a more complex management given its more complicated hospital course and higher mortality. A lot of research has emerged in the last years trying to explain the pathophysiology of CRS type 1 which remains in part poorly understood. This review primarily focuses on the hemodynamic and nonhemodynamic mechanisms involved in this syndrome.

Delayed Nephrology Consultation and High Mortality on Acute Kidney Injury: A Meta-Analysis

Background: Acute kidney injury (AKI) is a complex syndrome associated with substantial morbidity, mortality and costs. Despite advancements in diagnosis and care practice, AKI remains a disorder usually under/late-recognized with high mortality. One of the hidden reasons for poor outcome might be delayed nephrology consultation, with the involvement of the specialist only in severe stages of AKI when renal replacement therapy (RRT) is required. Methods: We searched PubMed, EMBASE and Cochrane central register for related work on the subject. Six studies were identified for the meta-analysis, correlating time of nephrology consultation and mortality in AKI. Results: We found that delayed nephrology consultation is associated with higher mortality in AKI, with an OR 0.79 (95% CI 0.48-1.10, p < 0.05). Conclusion: Delayed nephrology consultation contributes to higher mortality in AKI. The early involvement of nephrologist may present an advantage in terms of early recognition, prevention and effective treatment of AKI. An early involvement of multidisciplinary task force may contribute to better treatment, before the preventable complications of AKI occur or an emergency RRT is required.

Assessment of Sepsis-3 criteria and quick SOFA in patients with cirrhosis and bacterial infections

Introduction Patients with cirrhosis have a high risk of sepsis, which confers a poor prognosis. The systemic inflammatory response syndrome (SIRS) criteria have several limitations in cirrhosis. Recently, new criteria for sepsis (Sepsis-3) have been suggested in the general population (increase of Sequential Organ Failure Assessment (SOFA) ≥2 points from baseline). Outside the intensive care unit (ICU), the quick SOFA (qSOFA (at least two among alteration in mental status, systolic blood pressure ≤100 mm Hg or respiratory rate ≥22/min)) was suggested to screen for sepsis. These criteria have never been evaluated in patients with cirrhosis. The aim of the study was to assess the ability of Sepsis-3 criteria in predicting in-hospital mortality in patients with cirrhosis and bacterial/fungal infections. Methods 259 consecutive patients with cirrhosis and bacterial/fungal infections were prospectively included. Demographic, laboratory and microbiological data were collected at diagnosis of infection. Baseline SOFA was assessed using preadmission data. Patients were followed up until death, liver transplantation or discharge. Findings were externally validated (197 patients). Results Sepsis-3 and qSOFA had significantly greater discrimination for in-hospital mortality (area under the receiver operating characteristic (AUROC)=0.784 and 0.732, respectively) than SIRS (AUROC=0.606) (p<0.01 for both). Similar results were observed in the validation cohort. Sepsis-3 (subdistribution HR (sHR)=5.47; p=0.006), qSOFA (sHR=1.99; p=0.020), Chronic Liver Failure Consortium Acute Decompensation score (sHR=1.05; p=0.001) and C reactive protein (sHR=1.01;p=0.034) were found to be independent predictors of in-hospital mortality. Patients with Sepsis-3 had higher incidence of acute-on-chronic liver failure, septic shock and transfer to ICU than those without Sepsis-3. Conclusions Sepsis-3 criteria are more accurate than SIRS criteria in predicting the severity of infections in patients with cirrhosis. qSOFA is a useful bedside tool to assess risk for worse outcomes in these patients. Patients with Sepsis-3 and positive qSOFA deserve more intensive management and strict surveillance.

Cardiorenal Syndrome Type 5 in Sepsis: Role of Endotoxin in Cell Death Pathways and Inflammation

Background/Aims: Cardiorenal Syndrome Type 5 (CRS Type 5) is characterized by concomitant cardiac and renal dysfunction in the setting of different systemic disorders, such as sepsis. In this study, we investigated the possible relationship between endotoxin levels, renal cell death and inflammation in septic patients with CRS Type 5. Methods: We enrolled 11 patients with CRS Type 5. CRS Type 5 was defined according to the current classification system. AKI was defined by Acute Kidney Injury Network (AKIN) criteria. Acute cardiac dysfunction was documented by echocardiography as acute left and/or right ventricular dysfunction leading to decreased ejection fraction. Endotoxin activity was measured by the Endotoxin Activity Assay (EAA). Plasma from CRS Type 5 patients was incubated with renal tubular cells (RTCs) and cell death levels were evaluated. Plasma cytokines levels were measured as well. Results: Accordingly to EAA levels, patients were divided into two groups: 45.4% of patients had low endotoxin activity level (negative EAA), while 54.5% of patients showed high endotoxin activity (positive EAA). RTCs incubated with plasma from EAA positive patients showed significantly higher apoptosis levels and higher caspase-3 activation compared to cells incubated with plasma from EAA negative patients, and a significant positive correlation was observed between EAA levels and RTC apoptosis levels. Furthermore, IL-6 and IFN-γ levels were significantly higher in CRS Type 5 patients with positive EAA. Conclusion: Our data suggest a possible relationship between endotoxin levels and renal cell death in septic patients with CRS Type 5. Furthermore, this study highlights the presence of renal apoptosis, the immune deregulation and the strong inflammation in CRS Type 5 patients, especially in those with high endotoxin activity.

Gender differences in the quality of life of patients with liver cirrhosis related to hepatitis C after liver transplantation.

Background: Hepatitis C virus (HCV) infection frequently leads to chronic liver disease, which adversely affects the quality of life (QoL) of the patient. The gender of the patient may be an important variable in the way severity of the disease is perceived. The aim of our study is to evaluate the effect of the gender variable on QoL in HCV-positive patients. Methods: This study included a total of 52 patients (26 men and 26 women) who completed a 1-year follow-up after liver transplantation. QoL was assessed using the SF-36 questionnaire. Results: Male subjects have significantly higher scores on physical role functioning, bodily pain and physical activity compared with females. Females have a better QoL compared to males with regard to the emotional state and mental health. Conclusions: These results show a significant effect of the gender variable on QoL in HCV patients.

Advances in the Pathogenesis of Cardiorenal Syndrome Type 3

Cardiorenal syndrome (CRS) type 3 is a subclassification of the CRS whereby an episode of acute kidney injury (AKI) leads to the development of acute cardiac injury or dysfunction. In general, there is limited understanding of the pathophysiologic mechanisms involved in CRS type 3. An episode of AKI may have effects that depend on the severity and duration of AKI and that both directly and indirectly predispose to an acute cardiac event. Experimental data suggest that cardiac dysfunction may be related to immune system activation, inflammatory mediators release, oxidative stress, and cellular apoptosis which are well documented in the setting of AKI. Moreover, significant derangements, such as fluid and electrolyte imbalance, metabolic acidosis, and uremia, which are typical features of acute kidney injury, may impair cardiac function. In this review, we will focus on multiple factors possibly involved in the pathogenesis issues regarding CRS type 3.