Elevated Venous Pressure Research Articles

Anesthetic Management in Parturients With Fontan Physiology

Anesthetic Management in Parturients With Fontan Physiology

Feasibility and Utility of the Venous Excess Ultrasound Score to Detect and Grade Central Venous Pressure Elevation in Critically Ill Children.

The Venous Excess Ultrasound (VExUS) score has been described as a useful tool to estimate the degree of venous congestion in adult patients. The present study aimed to analyze the feasibility and usefulness of the VExUS score to detect and grade central venous pressure (CVP) elevation in critically ill children. A cross-sectional pilot study was conducted in a tertiary-care pediatric intensive care unit between November 2020 and June 2021. All children in whom CVP was monitored, were enrolled. At the time of central venous catheter placement, CVP and VExUS score grade were determined, analyzing the inferior vena cava (IVC) diameter and the hepatic (HVD), portal (PVD), and intrarenal (IRVD) venous Doppler waveforms. A total of 33 children were studied (median age 12.2 [interquartile range (IQR) 4.1-100.6] months old; median weight 8.5 [IQR 5.6-35] kg; 20 [60.6%] males). The VExUS score was successfully obtained in 100% of the patients and its severity was strongly associated with the CVP levels (P< .001). Analyzing the VExUS score components separately, IVC dilation (P< .001) and severe HVD (P= .026), mild IRVD (P= .005), and severe IRVD (P= .025) patterns were associated with elevated CVP. After adjustment for confounding factors, IRVD pattern remained the only independent variable associated with elevated CVP. The VExUS score appears to be a feasible and potentially useful bedside noninvasive monitoring tool for the detection and grading of CVP elevation in critically ill children. Among all its components, IRVD assessment seems most associated with high CVP in this population.

Reversible cognitive impairment and parkinsonism with leukoencephalopathy due to cranial dural arteriovenous fistula

Parkinsonism and rapid cognitive impairment may have many causes, but only a few have specific treatment. Cranial dural arteriovenous fistula (DAVF) represents 10-15% of intracranial arteriovenous malformations. Clinical manifestations depend on location and venous drainage. It is common the presence of pulsatile tinnitus, bruits and headache or headache and papilledema. Progressive cognitive decline is an unusual presentation due to bilateral thalamic edema or cortical venous hypertension. Endovascular or surgical treatment can reverse disease symptoms.We present a 74-year old man with rapidly progressive cognitive impairment and parkinsonism and a subsequent diagnosis of dural arteriovenous fistula (DAVF). Brain MRI revealed diffuse leukoencephalopathy probably attributable to elevated venous pressure. He was treated with partial embolization with Onix and left transverse sinus angioplasty. Following the procedure, there was a substantial reduction of venous pressure signs and remarkable clinical and imaging improvement, persisting at two years follow-up. This case represents an unusual presentation of DAVF. It is important to suspect the diagnosis of DAVF in cases with rapidly evolving cognitive impairment, parkinsonism and leukoencephalopathy as it can be reversible with early treatment.

Risk Assessment of Varicose Veins Among Teachers in Al-Ahsa, Saudi Arabia.

BackgroundVaricose veins (VV) are abnormally swollen, tortuous, and prominent veins caused by insufficient venous valves leading to venous congestion and elevated venous pressure. Prolonged standing at work has been proposed to be an important risk factor for varicose veins. Teachers are prone to have varicose veins due to prolonged standing. The aim of this study was to assess the risk of varicose veins among teachers in Al-Asha, Saudi Arabia.MethodThis was a cross-sectional study conducted among teachers of primary, secondary, and high schools in Al-Ahsa, of both genders, between April 2022 and June 2022. The participants were interviewed and examined for the presence of signs and symptoms of the disease. Finally, the collected data were analyzed using Statistical Package for Social Sciences (SPSS Inc., Chicago, IL, version 26.0 for Windows) software.ResultOut of 399 participating teachers with a mean age of 43.2 ± 12.9 years, 216 (54.1%) were males and the remainder were female. The commonest symptom was pain in the legs, which was exacerbated by work (43.1%). Most of the participants were working for more than 16 years (43.6%) and standing for less than six hours per day (72.7%). The most pointed sign was spider legs-shaped veins (23.8%). However, the least collective sign was paleness in the ulcer area after healing (1.8%). A total of 140 teachers had a family history of varicose veins, 74 of them (18.5%) were diagnosed with varicose veins previously. We summarize our result as female teachers who have a family history of VV have more risk to develop the disease.ConclusionThe prevalence of varicose veins was high among teachers in Al-Ahsa, Saudi Arabia. According to our study, teachers have a significant chance of developing the condition since their working style contributes to its progression. Further actions need to be made in order to increase awareness and prevent its complications.

Pleural Effusions in Patients With Congestive Heart Failure: Frequency, Pathogenesis, Diagnosis, and Implications.

Patients with cardiac disease frequently develop pleural effusions; the incidence is approximately 500,000 cases per year in the United States. These effusions often represent important clinical events for patients, indicating that either there has been an acute change in the patient's clinical status or the patient's chronic management program needs review. These effusions usually develop in both the right and left hemithorax but can be unilateral. The pathogenesis involves increased fluid transfer from parietal pleural capillaries into the pleural space and possibly decreased pleural fluid uptake into parietal pleural lymphatic structures. The increased fluid transfer develops due to increased capillary pressure secondary to elevated venous outflow pressure and secondary to decreased lymphatic flow into central vessels secondary to heart failure. Most pleural effusions associated with heart failure are transudates, but 20% to 25% have increased protein and lactate dehydrogenase levels suggesting an exudative process. Additional testing can clarify the situation and requires calculation of the serum albumin to pleural fluid albumin gradient or measurement of N-terminal pro-brain natriuretic peptide in the pleural fluid. An albumin gradient of greater than 1.2 g/dL suggests that the fluid is a transudate. The presence of a pleural effusion in a hospitalized patient at discharge is associated with an increased likelihood of rehospitalization and mortality within the next year. Patients with large symptomatic pleural effusions may require therapeutic thoracentesis. Recurrence of symptomatic effusions presents a management dilemma that might require repeated thoracenteses, indwelling intrapleural catheter placement, or other management steps used in advanced chronic heart failure.

Commentary: The genetics of pseudoexfoliation syndrome/glaucoma.

Genetics forms the basis of all life and evolution. The study of genetics primarily deals with trait inheritance and gene expression. Medical genetics has revolutionized the understanding of health and disease and opened several new prospects in prevention, diagnostics, and therapy. Genetic determinants of several ocular diseases are now well elucidated, with work in progress in many others. Ocular pseudoexfoliation (PXF) results from the accumulation of abnormal fibrillar aggregates in the anterior segment of the eye, blocking the trabecular meshwork and leading to glaucoma. These fibrils consist of elastic fiber components of elastin, fibrillin-1, fibulins, latent TGF-ß binding proteins, and the crosslinking enzyme lysyl oxidase-like 1 (LOXL1), produced by the epithelial cells in the anterior segment (lens epithelial cells, ciliary epithelial cells, and trabecular meshwork cells).[1] The LOXL1 locus on chromosome 15q24.1 has shown the most significant genetic association in PXF glaucoma, similar to the current study’s findings.[23] LOXL1 encodes a member of the lysyl oxidase (LOX) family of enzymes (LOX and LOXL1-4) required for lysine-derived covalent crosslinking in collagen and elastin, contributing to the tensile strength and elasticity of connective tissues. The LOXL1 isoform catalyzes the crosslinking of soluble tropoelastin into insoluble elastin in elastic fibers. Two common nonsynonymous protein-coding variants in exon 1 of the LOXL1 gene, rs1048661 (p.R141L) and rs3825942 (p.G153D), have consistently been associated with PXF in numerous population-based and well-powered genome-wide association studies (GWASs).[3] However, the phenomenon of allele reversal of these two variants in different ethnic populations reflects our ignorance of the exact biological mechanism underlying PXF and the need for further work in elucidating it.[4] Studies in transgenic mice models showed an inverse relationship between LOXL1 expression and intraocular pressure (IOP), with increased IOP in Loxl1-/- mice from elevated episcleral venous pressure.[5] LOXL1 animal models have been unsuccessful in duplicating the PXF phenomenon seen in humans, indicating additional unknown mechanisms. A deep resequencing approach has identified a single common variant (minor allele G of the intergenic sequence variant rs7173049: A>G) downstream of LOXL1 that downregulates two genes affecting vitamin A metabolism in ocular tissues in PXF patients. This allele did not show any reversal in different populations and suggested potential therapeutic targets.[6] The GWAS method identified another polymorphism outside of LOXL1, at 19p13, rs4926244, in the intronic region of CACNA1A, affecting calcium metabolism.[7] Another locus at 13q12 (proteasome maturation protein, POMP) showed increased strength of genetic association with increasing distance from the equator, consistent with the observed prevalence of ocular PXF, indicative of gene-environment interaction.[4] It is interesting to note that several other single nucleotide polymorphisms (SNPs) associated with PXF glaucoma have been identified in different ethnic groups. Multiple genetic loci identified in PXF open the prospect of developing polygenic risk scores (PRS) for PXF in the future. The prospect of gene–environment interactions has spawned several epigenetic investigations with exciting results. These include DNA hypermethylation in the promoter of the LOXL1 gene, downregulation of HSP70 (heat shock protein 70), long non-coding RNAs such as LOXL1 antisense RNA 1 (evidence for regulatory function in immortalized lens epithelial cells), and microRNAs, particularly miR-122-5p (shown to regulate the TGF-b/Smad signaling pathway and lipoprotein metabolism).[3] MicroRNAs are involved in the epigenetic regulation of gene expression and are potential biomarkers of disease identifiable in blood and aqueous humor. Mass spectrometric proteomic analyses of various biological samples have also revealed cellular stress/inflammation, lipid metabolism, coagulation, and dietary factors (altered vitamin D and retinol-binding proteins) contributing to PEX development. Specific metabolomic profiles in plasma and aqueous humor have been identified and validated using machine-learning prediction models.[3] These analyses implicate oxidative stress in the pathophysiology of PXF. However, there is a significant knowledge gap in the exact pathomechanism of the PXF syndrome that requires well-designed and extensive functional investigations. The vast proportion of work done in genetics in PXF comes from the developed world. Studies from India are extremely few, underlining the need to cover a lot of ground, particularly as genetics and epigenetics vary with ethnicity and region. Studies similar to this one and more extensive/multicentric investigations from different parts of India will go a long way in unraveling the specifics of PXF pathobiology among South Asians.[2] The primary challenge in conducting genetic research is the relative scarcity of geneticists/trained researchers in the developing world and funding requirements. Stalwarts in the field have called for equity in genomics.[8] The onus of responsibility lies on clinician-scientists to convince policy-makers and funding agencies for more significant funding in core research in this field.

New aspects in cardiorenal syndrome and HFpEF.

ABSTRACTCardiorenal syndrome (CRS) is a complex disease in which the heart and kidneys are simultaneously affected, and subsequently, the malfunction of one organ promotes the deterioration of the other. Heart failure (HF) with preserved ejection fraction (HFpEF) is the most common form of HF. The pathophysiology of CRS is not well known and several mechanisms have been proposed. An elevation of central venous pressure seems to be one of the key points to consider, among others such as an increase in intraabdominal pressure. Several diagnostic tools have been identified to establish the diagnosis of CRS in patients with HFpEF. Currently, the availability of biomarkers of renal and cardiac injury, the use of pulmonary ultrasound, the monitoring of the size of the inferior vena cava and the study of the renal venous pattern offer a new dimension in accurately diagnosing and quantifying organ damage in CRS. Beyond the symptomatic treatment of congestion, until recently specific therapeutic tools for patients with CRS and HFpEF were not available. Interestingly, the development of new drugs such as the angiotensin/neprilysin inhibitors and sodium-glucose cotransporter-2 (SGLT-2) inhibitors offer new therapeutic strategies with potential benefits in reduction of cardiorenal adverse outcomes in this population. Randomized clinical trials that focus on patients with HFpEF are currently ongoing to delineate optimal new treatments that may be able to modify their prognosis. In addition, multidisciplinary teamwork (nephrologist, cardiologist and nurse) is expected to decrease the number of visits and the rate of hospitalizations, with a subsequent patient benefit.

Liver Stiffness by Transient Elastography Correlates With Degree of Portal Hypertension in Common Variable Immunodeficiency Patients With Nodular Regenerative Hyperplasia.

Nodular regenerative hyperplasia (NRH) is associated with high morbidity and mortality in patients with common variable immunodeficiency (CVID). While liver biopsy is the gold standard for NRH diagnosis, a non-invasive technique could facilitate early disease recognition, monitoring, and/or immune intervention. We performed a cross-sectional analysis of ultrasound-based transient elastography (TE) in patients with CVID to evaluate liver stiffness and compared this between patients with (N = 12) and without (N = 6) biopsy-proven NRH. Additionally, these data were compared to a cohort followed at our institution for non-alcoholic fatty liver disease (NAFLD) (N = 527), a disease for which TE has routine diagnostic use. Clinical and pathologic features of NRH were evaluated as correlates of liver stiffness, and receiver operating characteristic curves were used to define a liver stiffness cutoff with diagnostic utility for NRH among CVID patients. CVID patients with NRH had a more severe disease presentation compared to those without. This included increased autoinflammatory disease comorbidities, combined B-cell and T-cell dysfunction, and abnormal liver biochemistries (specifically an increased mean alkaline phosphatase level [proximal to TE, 250 vs. 100 U/L; p = 0.03; peak, 314 vs. 114 U/L; p = 0.02). Results of TE demonstrated a significantly elevated liver stiffness in CVID patients with NRH (mean 13.2 ± 6.2 kPa) as compared to both CVID patients without NRH (mean 4.6 ± 0.9 kPa) and non-CVID patients with NAFLD (mean 6.9 ± 5.5 kPa) (p < 0.01). No single or composite histopathologic feature of NRH correlated with liver stiffness including nodule size, nodule density, sinusoidal dilation, fibrosis, and/or lymphocytosis. In contrast, liver stiffness by TE was significantly correlated with clinical parameters of portal hypertension, including an elevated hepatic venous pressure gradient, an increased splenic longitudinal diameter, presence of varices, and presence of peripheral edema. A liver stiffness of greater than or equal to 6.2 kPa was a clinically significant cutoff for NRH in CVID patients. We propose that TE has diagnostic utility in CVID, particularly in the presence of immunophenotypic features such as combined B-cell and T-cell dysfunction, autoinflammatory comorbidities, and/or abnormal liver tests. Elevated liver stiffness by TE should raise suspicion for NRH in patients with CVID and prompt expedited evaluation by hepatology.

Diuretic use in the adult Fontan

ObjectivesTo explore diuretic use in Fontan patients and its association with clinical features and adverse outcomes. BackgroundIn Fontan circulatory failure, ventricular dysfunction, chronically elevated systemic venous pressures, lymphatic abnormalities, and preload deprivation lead to volume expansion, prompting initiation of diuretics, yet use of diuretics has not been widely studied in the adult Fontan patient. MethodsSingle center retrospective review of Fontan patients ≥18 years between 2005 and 2018. Descriptive statistics compared Fontan patients by diuretic. Univariate logistic regression analyses were performed. Variables with a p value < 0.05 were selected to create multivariable model using backwards stepwise regression. Kaplan‐Meier product‐limit estimates stratified by diuretic use were used to find estimates of transplant and death rates. Log-rank tests were used to compare the time to outcome by diuretic use and Cox Proportional Hazards models examined the risk of transplant or death based on diuretic use. ResultsOf 206 Fontan patients, 96 (47%) were taking diuretics. Multivariable analysis demonstrated the following associated with diuretic use: age (Adjusted Odds Ratio [AOR] 1.06; p = 0.02); cyanosis (AOR 3.59; p=<0.01); tachyarrhythmia (AOR 2.64; p=<0.01); pacemaker (AOR 2.48; p = 0.02); ≥ moderate atrioventricular (AV) valve regurgitation (AOR 2.88; p=<0.05); New York Heart Association Class II-IV (AOR 3.41; p < 0.01). Diuretic use was associated with a 17-fold increased risk of transplant or death (95% CI 2.3–131.9; p=<0.01). ConclusionDiuretic use is common in adult Fontan patients. Multiple clinical correlates of heart failure were associated with diuretic use. Transplant-free survival was significantly reduced in those taking diuretics.

Secondary open-angle glaucoma: uveitic secondary glaucoma, steroid-induced glaucoma, posttraumatic and postoperative glaucoma, tumor-related glaucoma and glaucoma due to elevated episcleral venous pressure

Secondary open-angle glaucomas are aheterogeneous group of diseases in which avariety of pathophysiological mechanisms result in an elevation of intraocular pressure (IOP). In contrast to primary open-angle glaucoma in many cases besides IOP reduction acausal treatment is possible. This article is the second part of areview of the more frequently encountered forms of secondary open-angle glaucoma. Uveitic glaucoma, steroid-induced glaucoma, posttraumatic and postoperative glaucoma, glaucoma due to intraocular tumors and caused by elevated episcleral venous pressure are covered. The underlying pathophysiological mechanisms, characteristic clinical findings and treatment options are discussed.

Bioimpedance spectroscopy: Is a picture worth a thousand words?

Volume status can be difficult to assess in dialysis patients. Peripheral edema, elevated venous pressure, lung crackles, and hypertension are taught as signs of fluid overload, but sensitivity and specificity are poor. Bioimpedance technology has evolved from early single frequency to multifrequency machines which apply spectroscopic analysis (BIS), modeling data to physics-based mixture theory. Bioimpedance plots can aid the evaluation of hydration status and body composition. The challenge remains how to use this information to manage dialysis populations, particularly as interventions to improve over hydration, sarcopenia, and adiposity are not without side effects. It is therefore of no surprise that validation studies for BIS use in peritoneal dialysis patients are limited, and results from clinical trials are inconsistent and conflicting. Despite these limitations, BIS has clinical utility with potential to accurately evaluate small changes in body tissue components. This article explains the information a BIS plot ("picture") can provide and how it can contribute to the overall clinical assessment of a patient. However, it remains the role of the clinician to integrate information and devise treatment strategies to optimize competing patient risks, fluid and nutrition status, effects of high glucose PD fluids on membrane function, and quality of life issues.

Gallbladder Wall Thickness-Based Assessment of Organ Congestion in Patients With Heart Failure.

Background: Diffuse gallbladder (GB) wall thickening is caused by elevated systemic venous pressure, such as heart failure (HF). This study investigated the relationship between GB wall thickness (WT) and HF, and the prognostic impact of GBWT.Methods and Results: This prospective study included 116 patients with HF and 11 healthy controls. Among the 116 patients, 30 with GBWT measurements in the postprandial state or a history and/or signs of GB disease were excluded. The remaining 86 patients had significantly higher GBWT than the controls (median [interquartile range {IQR}] 2.0 [1.7–2.4] vs. 1.3 [1.1–1.6] mm, respectively; P<0.001). GBWT was significantly correlated with B-type natriuretic peptide (r=0.386, P<0.001), left atrial volume index (r=0.452, P<0.001), and tricuspid annular plane systolic excursion (r=−0.311, P=0.006). GBWT also exhibited a stepwise increasing relationship with increasing HF stage (Stage B, 22 patients, median [IQR] 1.8 [1.7–2.1] mm; Stage C, 60 patients, 2.0 [1.8–2.5] mm; and Stage D, 4 patients: 4.0 [3.5–4.5] mm). In Stage C or D HF patients, 11 hospitalizations for HF were observed over a median follow-up of 303 days (IQR 125–394 days). Furthermore, the rate of hospitalization events for HF was significantly higher in the high (≥3 mm) than low GBWT group (P=0.007).Conclusions: GBWT can be used to assess organ congestion in patients with HF.

Survival After Heart Transplant is Poor with High Venous Pressures and Low Arterial Elastance

<h3>Purpose</h3> High venous pressure is a risk factor for renal dysfunction and mortality in decompensated heart failure. Medical management involves lowering arterial elastance (Ea) with vasodilators. We hypothesized that high venous pressures and a low Ea may have a poor prognosis after heart transplantation due to impaired organ perfusion. <h3>Methods</h3> We retrospectively studied the effect of high venous pressures more than 15 mm hg on survival of 250 isolated heart transplants. Arterial elastance was calculated as E_sys / SV End systolic pressure E_sys = (2* systolic blood pressure + diastolic pressure) / 3 Organ perfusion pressure index (OPPI) was calculated as (Mean arterial pressure- RAP) / BSA <h3>Results</h3> Higher RAP was a significant risk factor for 90 day mortality (p = 0.007) . This risk decreased with increasing Ea (p = 0.000). Lower OPPI (p ∼0.000) had a significant effect on 90 day mortality. The impact of high RAP and low arterial elastance persisted at medium term follow up. Kaplan Meier estimates for survival at 5 years was significantly worse if RAP was more than 15 mm hg (p ∼ 0.0059) This effect of RAP on 5 year survival was absent if Ea was > 2.7.Survival at 5 years was significantly worse if OPPI was < 40. (p ∼ 0.0124).This effect was absent if RAP was < 15 mm hg. <h3>Conclusion</h3> Elevated venous pressure> 15 mm hg with low Ea has poor outcomes of transplantation . The effect seems to be mediated through a decrease in OPPI. A value of OPPI less than 40 mm hg is associated with poor outcomes.

Optic nerve ultrasound and cardiopulmonary bypass: A pilot study.

Introduction:Despite advances in surgical, anesthetic, perfusion, and postoperative care, adverse neurological consequences may occur following cardiac surgery and cardiopulmonary bypass (CPB). Consequences of the physiologic effects of CPB may alter the blood–brain barrier, autoregulation, and intracranial pressure (ICP) in the immediate postoperative period.Methods:We evaluated the effects of cardiac surgery and CPB on the central nervous system by measuring the optic nerve sheath diameter (ONSD) by using ultrasound as a surrogate marker of ICP. ONSD was measured after anesthetic induction and endotracheal intubation (time 1), after separation from CPB (time 2), and at the completion of the surgical procedure prior to leaving the OR (time 3).Results:The study cohort included 14 patients, ranging in age from newborn to 6 years. When comparing the Fontan group (n = 5) to the non-Fontan group (n = 9), four elevated ONSD observations were recorded for the Fontan patients during the study period, including one at time 1, one at time 2, and two at time 3. In Fontan versus non-Fontan patients, ONSD was greater at all three time points compared to non-Fontan. The change in the ONSD from time 1 to time 2 was greater (+0.2 mm vs. −0.1 mm), and the mean value at time 2 was significantly higher (4.2 vs. 3.5 mm, P = 0.048).Conclusions:Patients with Fontan physiology may be more prone to higher levels of baseline intracranial pressure due to elevated systemic venous pressure and decreased cardiac output. Alternatively, the chronically high central venous pressures may artificially elevate ONSD without clinical changes in ICP, necessitating the development of separate normative values based on the type of congenital heart disease.

Abdominal CT and MRI Findings of Portal Hypertension in Children and Adults with Fontan Circulation.

Background Portal hypertension in the Fontan circulation is a function of elevated systemic venous pressure and liver fibrosis. Purpose To quantify the prevalence of radiologic evidence of portal hypertension and elevated VAST score (one point each for varices, ascites, splenomegaly, and thrombocytopenia) of 2 or greater in children and adults with Fontan circulation and to determine the association with hemodynamics and adverse outcomes. Materials and Methods This was a retrospective study of individuals with Fontan circulation who underwent abdominal MRI or CT for focal liver lesion surveillance between January 2012 and December 2019. Portal hypertension was defined as the presence of at least two of the following: varices, ascites, or splenomegaly. Fontan deterioration was defined as a composite of heart failure signs or symptoms requiring diuretic escalation, placement of a ventricular assist device, heart transplant, or death. Relationships between variables and the composite end point were assessed using univariable and multivariable logistic regression. Results A total of 123 patients (age range, 9-55 years; 32 children) were evaluated (median age, 23 years; IQR, 17-30 years; 63 male patients). Median time since diagnosis of Fontan circulation was 16 years (IQR, 12-23 years). Twenty-five of the 123 patients (20%) had radiologic evidence of portal hypertension, and 34 (28%) had a VAST score of 2 or greater. Fontan deterioration occurred in 25 of the 123 patients (20%); median follow-up duration was 0.4 year (IQR, 0.1-3.1 years). Compared with patients who had Fontan circulation without deterioration, patients with Fontan deterioration were more likely to have moderate or severe ventricular systolic dysfunction (P < .01), moderate or severe atrioventricular valve regurgitation (P < .01), higher Fontan pressure (P = .01), radiologic evidence of portal hypertension (P < .01), and VAST score of 2 or greater (P < .01). Conclusion Radiologic evidence of portal hypertension at abdominal imaging in children and adults with Fontan circulation was associated with higher venous pressures and an increased risk for Fontan deterioration. These characteristics may be used to identify patients who warrant comprehensive hemodynamic evaluation. © RSNA, 2022.

Fontan-associated liver disease.

Fontan-associated liver disease.

Late Fontan Circulatory Failure. What Drives Systemic Venous Congestion and Low Cardiac Output in Adult Fontan Patients?

The Fontan circulation provides definite palliation for children born with a single anatomical or functional ventricle by diverting systemic venous blood directly to the pulmonary arteries, effectively rendering systemic venous return into portal vessels to the lung. Although this restores pulmonary blood flow and avoids the mixture of oxygenated and deoxygenated blood, it also results in elevated systemic venous pressures and low cardiac output. These are the two hallmarks of any Fontan circulation and the cause of Fontan circulatory failure later in life. We highlight the determinants of systemic venous return, its changed relationship with the pulmonary circulation, how it affects preload, and the changed role of the heart (myocardium, valves, and heart rate). By critically evaluating the components of the Fontan circulation, we hope to give some clues in how to optimize the Fontan circulation and avenues for future research.

Right-Sided Heart Failure and Cor Pulmonale in the Pediatric Patient.

Right-Sided Heart Failure and Cor Pulmonale in the Pediatric Patient.

Experimental Hemodynamics Within the Penn State Fontan Circulatory Assist Device.

For children born with a single functional ventricle, the Fontan operation bypasses the right ventricle by forming a four-way total cavopulmonary connection and adapts the existing ventricle for the systemic circulation. However, upon reaching adulthood, many Fontan patients exhibit low cardiac output and elevated venous pressure, eventually requiring a heart transplantation. Despite efforts in developing a new device or using an existing device for failing Fontan support, there is still no Food and Drug Administration-approved device for subpulmonary support. Penn State University is developing a hydrodynamically levitated Fontan circulatory assist device (FCAD) for bridge-to-transplant or destination therapy. The hemodynamics within the FCAD, at both steady and patient averaged pulsatile conditions for three physiological pump operating conditions, were quantified using particle image velocimetry (PIV) to determine the velocity magnitudes and Reynolds normal and shear stresses within the device. Data were acquired at three planes (0 mm and ±25% of the radius) for the inferior and superior vena cavae inlets and the pulmonary artery outlet. The inlets had a blunt velocity profile that became skewed toward the collecting volute as fluid approached the rotor. At the outlet, regardless of the flow condition, a high-velocity jet exited the volute and moved downstream in a helical pattern. Turbulent stresses observed at the volute exit were influenced by the rotor's rotation. Regardless of inlet conditions, the pump demonstrated advantageous behavior for clinical use with a predictable flow field and a low risk of platelet adhesion and hemolysis based on calculated wall shear rates and turbulent stresses, respectively.

Mechanical support for the failing single ventricle after Fontan

Mechanical support for the failing single ventricle after Fontan