Cardiovascular magnetic resonance measurements identified a hemodynamic pattern associated with death or heart-transplant referral or listing in people with Fontan circulation, according to a retrospective study of 182 patients followed at a moderate-altitude center. Patients who later experienced the composite outcome had a lower superior vena cava flow index than those who did not. In time-to-event analysis, each 0.1-liter-per-minute-per-square-meter increase in the indexed flow was associated with a 30% lower hazard of the outcome.

The association remained in an exploratory model that also included ventricular ejection fraction, but the researchers said the estimate requires prospective, multicenter validation before clinical application. The cohort comprised people who had undergone Fontan palliation between 1999 and 2021 at a tertiary institution approximately 5,118 feet above sea level. Fontan circulation passively directs systemic venous blood into the pulmonary arteries without the support of a sub-pulmonary ventricle.

Eligible participants had a clinically indicated CMR examination at least five years after Fontan completion, a threshold selected to match the center’s routine surveillance practice. For patients with multiple examinations, investigators used the last CMR obtained before an outcome or censoring. Most participants, 173 of 182, or 95%, had an extracardiac conduit Fontan circulation, and 76, or 42%, underwent a Damus–Kaye–Stansel anastomosis.

At CMR, the median body surface area was 1.43 square meters, with an interquartile range of 1.16 to 1.69 square meters. The median age at Fontan completion was 3.2 years, and the median interval between surgery and imaging was 10.9 years. Median follow-up after CMR was 4.7 years, while participants’ median home elevation was 5,221 feet above sea level.

Hypoplastic left heart syndrome was the most common underlying diagnosis, accounting for 35% of the cohort, followed by tricuspid atresia at 30%. The systemic ventricle was left-dominant in 53% and right-dominant in 47%. Magnetic resonance examinations were performed on 1.5- or 3.0-tesla scanners, with cine imaging used to assess ventricular function and phase-contrast sequences used to measure blood flow.

The primary endpoint combined death with referral or listing for heart transplantation. Fourteen patients, or 7.7% of the cohort, met that endpoint during follow-up: two died and 12 were referred or listed for transplantation. Among patients who experienced the outcome, the median time from CMR to the first qualifying event was 1.2 years, with an interquartile range of 0.5 to 2.5 years.

The median superior vena cava flow index was 0.54 liters per minute per square meter among patients with the primary outcome, compared with 0.82 liters per minute per square meter among those without it; the difference was statistically significant, with a p-value of 0.011. The superior vena cava-to-ascending-aorta flow ratio was also lower in the event group, with medians of 0.22 and 0.30, respectively. Several other CMR flow measures did not differ significantly between patients with and without the primary outcome.

These included flow indices in the ascending aorta, right pulmonary artery, left pulmonary artery and inferior vena cava, as well as calculated systemic-to-pulmonary collateral flow. Receiver operating characteristic analysis indicated that superior vena cava flow index discriminated between patients who met the endpoint and those who did not with an area under the curve of 0.74 and a 95% confidence interval of 0.56 to 0.92. A data-derived threshold of 0.66 liters per minute per square meter, selected using the Youden index, yielded 70% sensitivity and 75% specificity.

Kaplan–Meier curves showed significantly poorer event-free survival among patients below that threshold. Because the threshold and discrimination measures came from the same cohort, they are exploratory rather than externally validated clinical cutoffs. Univariable Cox proportional hazards regression found a hazard ratio of 0.70 for each 0.1-liter-per-minute-per-square-meter increase in superior vena cava flow index, with a 95% confidence interval of 0.50 to 0.92 and a p-value of 0.008.

Right-dominant ventricular morphology was also associated with a higher hazard than left-ventricular dominance, with a hazard ratio of 3.21, a 95% confidence interval of 1.00 to 10.29 and a p-value of 0.049. The investigators constructed a two-variable Cox model containing superior vena cava flow index and ejection fraction. Each one-percentage-point increase in ejection fraction was associated with an adjusted hazard ratio of 0.92, with a 95% confidence interval of 0.86 to 0.97.

Because only 14 primary events occurred, the multivariable analysis was deliberately restricted and was intended to test whether the flow association persisted beyond ventricular function rather than develop a full prediction model. Internal bootstrap analysis using 2,500 resamples produced a median hazard ratio of 0.71 for superior vena cava flow index and 0.92 for ejection fraction, close to the original adjusted estimates. Collinearity between the two variables was negligible, with a Spearman absolute correlation below 0.1, an R-squared value of 0.008 and a variance inflation factor of 1.01.

Tests did not indicate violation of the proportional-hazards assumption. Ventricular measures also differed according to morphology: in the right-dominant subgroup, patients with events had larger indexed ventricular volumes and lower ejection fraction than those without events, whereas comparable differences were not statistically significant in the smaller left-dominant event subgroup. The study does not establish why lower superior vena cava flow was associated with poorer outcomes.

One proposed explanation is that chronic hypobaric exposure at moderate altitude promotes pulmonary vasoconstriction and raises pulmonary vascular resistance, potentially restricting passive flow through the Fontan pathway. However, pulmonary vascular resistance was not directly measured, and the cohort included no sea-level comparator, so the study cannot determine whether altitude caused the observed hemodynamic pattern. Other possible contributors include anatomical differences in the superior vena cava, systemic venovenous collateral vessels that divert blood around the pulmonary vascular bed, and differences in preload or single-ventricle filling.

The findings therefore associate reduced indexed flow with an unfavorable hemodynamic state rather than demonstrate a specific underlying mechanism. Important limitations constrain the results. The retrospective, single-center design creates the possibility of selection bias, and clinically performed CMR examinations were not acquired at standardized surveillance intervals.

Selecting the last scan before an outcome or censoring may introduce reverse-causation bias because patients approaching clinical deterioration could have been imaged nearer the event. Clinically relevant potential confounders—including functional class, cardiopulmonary exercise capacity, resting oxygen saturation, natriuretic peptide levels, catheterization-derived Fontan pressure and pulmonary vascular resistance, pulmonary vasodilator therapy, arrhythmia burden and the severity of liver disease—were unavailable or not incorporated. The small number of events also leaves the multivariable estimates vulnerable to overfitting despite the deliberately parsimonious model and bootstrap resampling.

Furthermore, the predominance of fenestrated extracardiac conduit Fontan circulation limits generalizability to other surgical configurations. The results position superior vena cava flow index as a candidate prognostic marker that may complement ventricular size and ejection fraction in longitudinal assessment of Fontan circulation, but they do not establish a clinical measurement rule or treatment strategy. Prospective, multicenter studies comparing cohorts across elevations would be needed to test the temporal relationship, determine whether altitude modifies the association, and establish external validity.

The authors also identified four-dimensional flow CMR as a possible tool for characterizing three-dimensional flow patterns and energy loss within the Fontan pathway. Further work could compare imaging signatures with exercise physiology, biomarkers of end-organ dysfunction and pulmonary vascular imaging. Until those studies are completed, the association between reduced superior vena cava flow and adverse outcomes should be regarded as an exploratory finding that requires independent validation.

Subject of Research: Association between CMR-derived blood flow and adverse outcomes in people with Fontan circulation

Article Title: Cardiovascular magnetic resonance–derived hemodynamics predict adverse outcomes after Fontan palliation

Article References: Platnick, C., Frank, B., Romanowicz, J., Gonzalez De Alba, C., Chase, M., Umer, A., Chaudhuri, N. R., Awori, J., Chauhan, D., Mascio, C. E., Udassi, J. P., & Hedjazi Moghari, M. (2026). Cardiovascular magnetic resonance–derived hemodynamics predict adverse outcomes after Fontan palliation. Frontiers in Cardiovascular Medicine, 13, Article 1937933. https://doi.org/10.3389/fcvm.2026.1937933

Image Credits: AI Generated

DOI: 10.3389/fcvm.2026.1937933

Keywords: Fontan circulation, cardiovascular magnetic resonance, superior vena cava flow, heart transplantation, congenital heart disease, risk stratification, ventricular function, moderate altitude, flow quantification, retrospective cohort, Cardiovascular, magnetic

Dr. Pierre Kory: "It is a myth that vaccines are safe and necessary...If I had young children today, they would not receive a single vaccine."

New data reveal major geographic disparities and highlight the urgent need for global action on prevention, early detection, and equitable access to treatment. For roughly one in five people worldwide, cancer will become part of their lifetime. Global Cancer Statistics, 2026 estimates that nearly 21 million people were diagnosed with cancer in 2024 and 9.8 [...]

A new analysis revisits the Great Barrier Reef’s past losses of Acropora corals, showing that reef decline was not only a modern story of warming oceans. Using historical ecological records alongside climate-linked environmental data, the study links earlier episodes of Acropora mortality to shifting variability in ocean conditions—factors that can amplify heat stress even before today’s extremes fully arrive. The findings suggest that the reef’s vulnerability has deep roots, shaped by how the atmosphere and oceans interact over time.

The researchers focus on Acropora, a genus that forms structurally complex habitats and supports high biodiversity. When these branching corals die, the consequences cascade: shelter and food sources shrink, juvenile recruitment becomes harder, and reef recovery slows. Their approach connects mortality signals across time to measures of climate variability, aiming to distinguish natural swings from persistent human-driven pressures.

Clues come from patterns consistent with stress events driven by warmer-than-usual water, altered temperature dynamics, and changing conditions that influence coral physiology. Importantly, the work frames these stressors as interacting rather than acting alone. Climate variability can raise the frequency and severity of harmful conditions, while human impacts provide chronic background stress that reduces coral resilience.

The study emphasizes that anthropogenic impacts—such as local water-quality degradation and other human pressures—can intensify the damage caused during climate-driven heat or disturbance events. In this view, the reef does not simply “survive” or “collapse” based on temperature alone; it fails when multiple stressors converge, tipping corals past thresholds for survival and regrowth.

This “multi-stressor” model matters for forecasts. If past mortality aligns with periods of heightened climate variability, then future reef risk depends not only on long-term warming trends but also on how variability evolves. That means management strategies must be tuned to both the climate signal and the local pressures that determine how quickly corals can bounce back after shocks.

The authors also highlight that historical mortality patterns can function like a preview of likely future dynamics. Instead of treating recent bleaching as the first chapter, the analysis portrays a longer timeline of stress accumulation. The reef’s trajectory, they argue, reflects a system that has repeatedly been strained and partially recovered—until cumulative impacts made recovery less complete.

With the Great Barrier Reef facing intensifying marine heatwaves, this work adds urgency to climate mitigation and local conservation. It suggests that reducing human pressures can buy time by strengthening coral tolerance, even as global temperatures continue to rise. In viral science terms, the message is clear: the reef’s past predicts its future—and human actions can still change the ending.

Subject of Research: Great Barrier Reef coral (Acropora) mortality
Article Title: Past Acropora mortality on the Great Barrier Reef linked to climate variability and anthropogenic impacts.
Article References: Clark, T.R., Leonard, N.D., Jupiter, S.D. et al. (2026). Commun Earth Environ. https://doi.org/10.1038/s43247-026-03800-9
Image Credits: AI Generated
DOI: 10.1038/s43247-026-03800-9

In a groundbreaking retrospective cohort study set to reshape preoperative evaluations, researchers have unveiled compelling evidence linking preoperative hyponatremia with significantly heightened risks of postoperative complications and mortality in elderly patients undergoing hip fracture surgery. Published in BMC Geriatrics, the study meticulously investigates how a seemingly subtle electrolyte imbalance can precipitate a cascade of adverse outcomes, transforming the landscape of geriatric orthopedic care.

Hip fractures in geriatric populations remain a daunting global health challenge, often precipitating a downward spiral in functional status and quality of life. While surgical intervention typically offers the best chance for recovery, the preoperative physiological status of these patients profoundly influences their prognoses. Sodium, a critical electrolyte governing cellular function and fluid balance, emerges as a pivotal biomarker in this investigation. Hyponatremia, defined by a clinically low serum sodium concentration, manifests frequently in elderly individuals due to multifactorial etiologies including chronic comorbidities and medication effects.

The research team rigorously analyzed retrospective data comprising extensive clinical records of geriatric patients admitted for hip fracture surgeries. Through advanced statistical modeling and adjustment for confounding variables such as age, comorbidity profiles, and fracture severity, the study delineated a clear association: preoperative hyponatremia markedly increases the incidence of postoperative complications including infections, delayed wound healing, and cardiovascular events. These complications carry a compounded risk, often prolonging hospitalization and necessitating intensive care interventions.

Highlighting the pathophysiological underpinnings, hyponatremia disrupts neuronal function and cerebral homeostasis, rendering patients more susceptible to delirium and impairments in sensorium postoperatively. These neurological complications contribute substantially to morbidity and complicate rehabilitation trajectories. Additionally, the electrolyte imbalance compromises cellular osmoregulation, potentially exacerbating inflammatory responses and impairing immune defense mechanisms during the critical postoperative period.

The longitudinal dimension of this study offers unprecedented insight into mortality trends extending from the immediate postoperative phase to the long term. Patients exhibiting preoperative hyponatremia experienced significantly higher mortality rates spanning months to years after surgery, underscoring the enduring impact of electrolyte disturbances beyond acute hospitalization. This trend accentuates the necessity for early identification and correction of hyponatremia to improve survival outcomes.

Intriguingly, the study also explores the potential for hyponatremia to act as a surrogate marker for frailty and systemic physiological decline rather than merely an isolated laboratory anomaly. Detailed subgroup analyses suggest that patients with hyponatremia often harbor multiple concurrent vulnerabilities, compounding their risk profiles. This observation prompts a paradigm shift, advocating for integrated geriatric assessments that encompass biochemical, functional, and nutritional parameters to optimize perioperative care.

From a therapeutic perspective, the findings implicate preoperative sodium normalization as a potentially modifiable factor in risk mitigation strategies. Interventions may include cautious fluid management, electrolyte supplementation, and tailored pharmacotherapy designed to stabilize serum sodium levels without precipitating osmotic demyelination syndrome, a rare but severe complication of rapid correction. The study calls for randomized controlled trials to establish evidence-based protocols for managing hyponatremia in this delicate patient cohort.

Moreover, this research injects urgency into the discourse surrounding perioperative risk stratification tools. Existing models often underrepresent electrolyte abnormalities, focusing predominantly on cardiovascular and respiratory function. Incorporating sodium levels into predictive algorithms could enhance clinical decision-making, enabling surgeons, anesthesiologists, and geriatricians to identify high-risk individuals necessitating intensified monitoring and resource allocation.

The implications extend beyond individual patient management to healthcare systems and policy frameworks. Given the aging global population and escalating incidence of geriatric hip fractures, optimizing preoperative metabolic status could translate into reduced healthcare expenditures by lowering complication rates, shortening hospital stays, and minimizing readmission frequencies. This cost-effectiveness dimension positions preoperative hyponatremia screening as a pragmatic intervention with wide-reaching benefits.

Critically, the study’s retrospective design, while powerful, inherently limits causal inferences. Confounding factors, although rigorously controlled, cannot be entirely excluded. Nonetheless, the consistent associations revealed across a large diverse sample lend robust credibility to the conclusions. Prospective, multicenter studies are warranted to validate these findings and explore mechanistic pathways at the molecular and cellular levels that link sodium dysregulation with adverse surgical outcomes.

The researchers also emphasize the importance of interdisciplinary collaboration, urging orthopedic surgeons to engage endocrinologists and nephrologists in the perioperative optimization process. Proactive management strategies encompass not only sodium correction but also comprehensive evaluation of renal function, hydration status, and medication regimens, particularly diuretics and psychotropics which commonly induce hyponatremia.

Importantly, patient education emerges as a valuable component in the preoperative workflow. Informing elderly patients and their caregivers about the significance of electrolyte balance empowers adherence to medical advice and facilitates early symptom reporting. Such engagement can enhance outpatient management of chronic conditions predisposing to hyponatremia, potentially preventing fractures and improving surgical readiness.

The study’s extensive data set further reveals disparities in the prevalence of hyponatremia across demographic and socio-economic strata, suggesting underlying inequities in healthcare access and chronic disease management. Addressing these social determinants is imperative to reduce the burden of postoperative complications and enhance equity in surgical outcomes among the elderly.

In conclusion, the association between preoperative hyponatremia and adverse postoperative trajectories in geriatric hip fracture patients demands urgent attention from the medical community. This study pioneers a vital link in perioperative medicine, emphasizing the profound impact of electrolyte homeostasis on surgical resilience and long-term survival. Integrating these insights into clinical practice promises to elevate the standard of care, transforming outcomes for one of the most vulnerable patient populations.

Subject of Research:
Article Title:
Article References:

Xi, C., Wan, M., Wu, H. et al. Preoperative hyponatremia is associated with increased postoperative complications and short- to long-term mortality in geriatric hip fracture patients: a retrospective cohort study. BMC Geriatr (2026). https://doi.org/10.1186/s12877-026-07833-9

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New research indicates that a moderate amount of weekly strength training may be associated with the greatest longevity benefits, especially when paired with regular aerobic exercise. For years, exercise advice has focused heavily on getting enough cardio. But a major new study suggests that what you do with your muscles may be just as important [...]

There was no actual pandemic but there have been 17 million deaths due to the COVID-19 mRNA vaccines so far. These vaccines were launched without proper safety trials. Mortality rates and cancers increased post-vaccination due to immune system destruction.