Christopher McIntyre

Christopher McIntyre

This protocol describes an ongoing multi-centre randomized controlled trial evaluating the effects of a 12-week intradialytic cycling program for patients receiving maintenance hemodialysis. Researchers are investigating whether exercising on a stationary bicycle during dialysis treatments can reduce hemodialysis-induced myocardial stunning, a form of temporary heart injury caused by reduced blood flow. By mitigating this injury, the intervention aims to improve vital organ perfusion, reduce symptom burden, and improve overall cardiovascular outcomes in this high-risk population.

Christopher McIntyreArsh Jain

This study compared the effects of different dialysis methods on brain health by tracking changes in brain structure over one year. Researchers found that patients receiving hemodialysis experienced more progressive white matter injury in the brain compared to those undergoing peritoneal dialysis. These findings suggest that the choice of dialysis modality may influence the risk of brain injury in patients with kidney failure.

Christopher McIntyreArsh Jain

This study used advanced brain imaging and cognitive testing to examine how peritoneal dialysis affects the brain compared to the known risks of hemodialysis. Researchers found that while patients on peritoneal dialysis experienced significant increases in brain glucose levels during treatment, they did not show the acute signs of restricted blood flow or brain injury typically seen in hemodialysis patients. Despite this protective effect on brain structure, many participants still demonstrated difficulties with memory, attention, and executive function during cognitive assessments.

Christopher McIntyre

This commentary cautions against directly extending findings from sodium-glucose cotransporter-2 inhibitor trials to children with congenital anomalies of the kidney and urinary tract. The authors highlight the need for phenotype-specific safety considerations in this pediatric population, given their unique anatomical and physiological characteristics. They emphasize that safety profiles established in adults with other forms of chronic kidney disease may not directly translate to children with structural kidney abnormalities.

Christopher McIntyre

This protocol describes the design of an ongoing multicentre randomized controlled trial evaluating the impact of a 12-week intradialytic cycling program on hemodialysis-induced heart muscle stunning. Researchers will measure changes in regional wall motion abnormalities during dialysis, alongside secondary outcomes like cognitive function, recovery time, and symptom burden. The study aims to determine if exercise during dialysis can mitigate cardiac injury and improve patient-reported symptoms and functional status.

Christopher McIntyre

This commentary discusses how hemodialysis can cause repeated, temporary drops in blood flow to the brain, leading to impaired cerebrovascular reactivity and cognitive decline. It highlights the need to understand these dialysis-induced brain injuries and explore potential protective strategies for patients. Ultimately, addressing these circulatory insults is crucial for preserving cognitive function in individuals undergoing long-term dialysis.

Christopher McIntyre

This review examines the technical challenges and potential errors in using bioimpedance to estimate fluid volumes in patients undergoing hemodialysis. The authors demonstrate through data simulation that standard wrist-to-ankle bioimpedance measurements tend to underestimate extracellular fluid volume as a patient's body fat percentage increases. They suggest that using segmental measurements or incorporating subject-specific body shape corrections, such as those from three-dimensional smartphone scans, can improve the accuracy of these fluid assessments.

Christopher McIntyre

This study examined whether expanded hemodialysis, which uses a specialized filter, could improve quality of life and symptom burden compared to standard hemodialysis. Over 15 months, 47 patients in Ontario, Canada, switched between standard hemodialysis and expanded hemodialysis while tracking their symptoms using a dynamic patient-reported outcomes tool. Expanded hemodialysis led to durable improvements in overall quality of life, energy, sleep, and pain, with symptoms worsening when patients switched back to standard hemodialysis.

Christopher McIntyre

Using an animal model, researchers investigated how different sodium concentrations in dialysis fluid affect blood vessel health and blood flow during hemodialysis. They found that hemodialysis itself causes acute injury to the protective lining of blood vessels and reduces blood flow, but these harmful effects were significantly worsened when a high-sodium dialysis fluid was used. This suggests that exposing patients to high sodium levels during dialysis may aggravate blood vessel damage.

Christopher McIntyre

A study of thirteen patients undergoing maintenance hemodialysis used advanced heart imaging to examine how dialysis affects blood flow to the heart muscle. Researchers found that hemodialysis reduced blood flow and caused temporary heart muscle dysfunction even in patients without coronary artery disease. In patients who did have coronary artery disease, these negative effects on heart perfusion and contraction were even more pronounced and persisted after the dialysis session ended.

Christopher McIntyre

This study protocol describes an ongoing project evaluating whether digital arts-based training, such as music or photography editing, can help teenagers use social media in healthier, more goal-oriented ways. Researchers will compare adolescents participating in a three-month digital arts programme to a control group, measuring changes in social media habits, attention, mood, and brain connectivity using advanced imaging. The goal is to determine if creative digital interventions can mitigate the negative mental health and cognitive effects associated with social media overuse.

Christopher McIntyreArsh Jain

Patients receiving maintenance dialysis often experience faster and more severe cognitive decline compared to those with advanced kidney disease who are not on dialysis. This review explores how both hemodialysis and peritoneal dialysis can cause structural and functional brain changes, leading to symptoms ranging from short-term confusion and brain fog to long-term loss of cognitive ability. The authors examine the underlying biological mechanisms of this decline and discuss potential medical interventions to protect brain health in this population.

Christopher McIntyre

Using a rat model of hemodialysis, researchers compared how different types of dialyzer membranes affect blood flow in tiny blood vessels. They found that conventional high-flux polysulfone dialyzers caused a twenty-five percent reduction in microvascular tissue perfusion, whereas newer mid-cut-off dialyzers preserved this blood flow. The conventional dialyzers also showed higher activation of the complement immune pathway, suggesting that dialyzer membrane design plays a key role in preventing tissue-damaging drops in blood flow during treatment.

Christopher McIntyre

This review explores the potential of advanced functional magnetic resonance imaging techniques, including multi-parametric and multi-nuclear imaging, to assess kidney function in children. These non-invasive methods can evaluate kidney perfusion, tissue oxygenation, and scarring without the need for a biopsy, and can track sodium and phosphate levels to monitor specific kidney disorders. Because these techniques do not use radiation, they are particularly well-suited for safely monitoring pediatric kidney health over time.

Christopher McIntyre

Researchers developed and tested a novel, sodium-free intraperitoneal solution containing 30% icodextrin and 10% dextrose to optimize fluid and sodium removal. In animal models and a small study of ten human patients with kidney failure, this new solution removed significantly more water and sodium than standard peritoneal dialysis solutions without causing serious adverse events or tissue damage. These findings suggest the solution could be a highly effective treatment for managing fluid overload in patients with kidney failure or other swelling disorders like heart failure.

Christopher McIntyre

This pilot study evaluated the feasibility of using sodium magnetic resonance imaging to assess residual kidney function in patients receiving hemodialysis by measuring the sodium gradient between the inner and outer parts of the kidney. Researchers found that healthy volunteers had a significantly higher sodium gradient than patients on hemodialysis, and this gradient correlated closely with urine concentration. This imaging technique may provide a new way to evaluate remaining kidney tubule function in dialysis patients, which is currently difficult to measure in clinical practice.

Christopher McIntyre

In a small study of 19 people receiving hemodialysis who had not responded well to usual care, clinicians used detailed monitoring to tailor several parts of dialysis to each person over two weeks. The programme was associated with better quality of life, much shorter recovery times, fewer blood pressure drops, less weight gain between treatments, and less dialysis-related heart injury; three people were later listed for transplantation and two received a transplant. These results suggest that individualized dialysis care may make treatment safer and more tolerable for people who struggle with standard approaches.

Christopher McIntyre

This 15-month study examined what happened when 47 people receiving in-centre hemodialysis in Ontario switched between expanded hemodialysis and their usual treatment, using repeated questionnaires about quality of life and symptoms. Expanded hemodialysis improved overall quality of life and several symptoms, including low energy, poor sleep, itching, pain, and recovery after treatment; these benefits persisted during treatment and became smaller when usual dialysis resumed.

Christopher McIntyre

Researchers tested a new salt-free dialysis fluid in 10 adults already receiving peritoneal dialysis. After a single treatment lasting four to six hours, participants had mild to moderate abdominal discomfort but no meaningful changes in blood pressure, heart function, or blood sodium, while removing about five grams of sodium and two litres of fluid. These early findings suggest the solution was tolerated and may improve salt and fluid removal during peritoneal dialysis.

Christopher McIntyre

In a small pilot study, five people receiving hemodialysis who had difficult-to-control fluid weight gain received two brief treatments each week that used the abdominal lining to remove extra salt and fluid after dialysis. Their between-treatment weight gain fell over three weeks, and the treatment was generally well tolerated, although blood sodium levels decreased modestly. Blood pressure and other measured markers stayed stable, while heart imaging suggested less dialysis-related heart strain in two of the three patients with usable images.

Christopher McIntyre

In a rat model of haemodialysis, researchers compared two types of dialysis filters and measured blood flow through small vessels in muscle. The conventional polysulfone filter reduced this blood flow and triggered more activation of part of the immune system, while the newer mid-cut-off filter preserved blood flow without changing the removal of small waste products. These findings suggest that filter materials may affect tissue circulation during dialysis and can be evaluated in animal models before human studies.

Christopher McIntyre

Researchers used a non-invasive magnetic resonance imaging technique to measure calf muscle structure in 85 people with chronic kidney disease, including people receiving dialysis and people with both heart and kidney problems. Muscle patterns were more irregular in those receiving dialysis or with both heart and kidney problems than in people with chronic kidney disease who were not receiving dialysis, and the imaging findings were related to blood markers of kidney and mineral health. This approach could offer a way to assess muscle wasting and structural changes without a biopsy.

Christopher McIntyre

This study followed a group of patients diagnosed with stage 3 chronic kidney disease in primary care over nearly ten years to see how fluctuations in their diagnostic criteria affected long-term outcomes. Researchers found that more than a quarter of the patients experienced periods of "remission," where their kidney function measurements temporarily improved to normal levels. While patients who experienced these periods of remission had a significantly lower risk of death and kidney disease progression compared to those with persistent disease, they still remained at risk and required ongoing monitoring.

Christopher McIntyre

This pilot study used advanced sodium magnetic resonance imaging to evaluate the kidney's tubular function in patients undergoing peritoneal dialysis compared to those on hemodialysis. Although peritoneal dialysis patients typically maintain higher urine volumes, the imaging revealed that both groups had similarly reduced levels of tubular function, specifically in their ability to concentrate urine. These findings suggest that measuring urine volume alone provides an incomplete picture of residual kidney health in dialysis patients.

Christopher McIntyre

This study evaluated the impact of expanded hemodialysis, which uses a medium cut-off dialyzer to remove a broader range of toxins, on the quality of life and symptom burden of patients receiving maintenance hemodialysis in Ontario, Canada. Using a specialized patient-reported outcome tool, researchers found that switching to expanded hemodialysis significantly improved general well-being, energy, sleep quality, and pain, with benefits remaining durable over time. These improvements gradually declined when patients were switched back to conventional high-flux hemodialysis.

Christopher McIntyre

Researchers evaluated a patient optimization program designed to deliver individualized, complex interventions for vulnerable hemodialysis patients who had poor tolerance to standard treatments. For the thirteen patients who completed the program, the personalized approach led to significant improvements in quality of life, energy levels, and blood pressure, while also reducing post-dialysis recovery time and dialysis-induced heart muscle injury. These findings suggest that tailoring dialysis prescriptions to individual patient physiology can successfully improve both subjective well-being and objective clinical outcomes.

Christopher McIntyre

This proof-of-concept study evaluated the feasibility of using sodium magnetic resonance imaging to measure the sodium concentration within kidney cysts in four patients with autosomal dominant polycystic kidney disease. The researchers successfully captured sodium images of the kidneys, revealing a wide and previously unappreciated range of sodium content across different cysts. This imaging technique could eventually help clinicians assess the metabolic activity of cysts to improve prognosis and monitor responses to treatment without invasive procedures.

Christopher McIntyreAmit Garg

This systematic review and meta-analysis evaluated the impact of exercise during hemodialysis sessions on cardiovascular health in adults with kidney failure. Analyzing data from thirty-two studies, researchers found that intradialytic exercise, primarily aerobic, significantly reduced arterial stiffness and improved diastolic blood pressure, heart pumping function, and heart rate variability compared to standard care. These findings suggest that incorporating exercise programs during dialysis treatments can meaningfully improve several physiological measures of cardiovascular health.

Christopher McIntyre

This review examines how the circulatory stress of recurrent hemodialysis causes abnormal blood flow and progressive, irreversible damage to vital organs like the brain and heart. It explores the underlying biological mechanisms of this vascular injury and discusses potential therapeutic strategies to protect patients from these complications. Ultimately, addressing these issues is critical to reducing the high rates of cardiovascular disease and premature death in people receiving hemodialysis.

Christopher McIntyreSusan Huang

Researchers studied whether adults with X-linked hypophosphatemia, a rare genetic condition causing high levels of a hormone called fibroblast growth factor 23, have an increased risk of heart disease or high blood pressure. In a group of twenty-two patients, the study found that most had normal heart structure and blood pressure, with no signs of stiffening in the arteries. These findings suggest that the elevated hormone levels associated with this specific genetic condition may not carry the same cardiovascular risks as seen in patients with chronic kidney disease.

Christopher McIntyre

Researchers evaluated a new multiplex testing panel that measures 21 different proteins in blood and urine samples from healthy individuals, critically ill patients with acute kidney injury, and patients with chronic or end-stage kidney disease. They identified unique protein profiles that could accurately distinguish patients with kidney injury or disease from healthy controls, with specific markers like TIMP-1 and osteoactivin showing high predictive value. These findings demonstrate the potential of using multi-protein panels to better characterize and profile different stages of kidney dysfunction.

Christopher McIntyre

This study compared the attitudes of adolescents with chronic conditions and their caregivers toward telemedicine before and during the COVID-19 pandemic. While caregivers continued to prefer telemedicine over in-person visits for safety and convenience, adolescents shifted their preference toward more in-person visits during the pandemic, placing a higher value on the personal connection, comfort, and communication of face-to-face consultations. Interestingly, pre-pandemic concerns such as technical frustrations and adolescents not taking virtual appointments seriously largely disappeared during the pandemic.

Christopher McIntyre

This review examines the practice of cooling dialysis fluid to prevent drop in blood pressure and protect organs like the heart and brain from stress during hemodialysis. While smaller studies previously suggested benefits, a recent large-scale trial found that a center-wide policy of using cooler dialysis fluid did not improve cardiovascular outcomes. The authors discuss why cooler dialysate may still be useful for certain individual patients rather than being completely abandoned.

Christopher McIntyre

This study evaluated whether non-invasive skin perfusion monitoring using photoplethysmography could detect hemodialysis-induced heart injury in twelve patients. Researchers found that a significant reduction in skin pulse strength during dialysis was associated with both decreased myocardial perfusion and the development of regional heart wall motion abnormalities, which indicate myocardial stunning. The findings suggest that monitoring skin perfusion is a promising, non-invasive way to detect and manage circulatory stress and heart injury during hemodialysis treatments.

Christopher McIntyre

This review highlights recent progress in sodium magnetic resonance imaging, a technology used to detect excess sodium accumulation in tissues like the skin, heart, and kidneys. Researchers have linked this tissue sodium buildup to declining kidney function, inflammation, and cardiovascular issues across the entire spectrum of chronic kidney disease. The article discusses how this imaging technique could serve as a valuable tool in future clinical trials and patient care.

Christopher McIntyre

Using advanced magnetic resonance imaging and spectroscopy during active hemodialysis sessions, researchers found direct evidence of acute brain injury in patients. The study revealed brain tissue changes consistent with swelling and chemical markers of oxygen deprivation during the period of maximum circulatory stress. These findings suggest that even a single hemodialysis session can cause acute, ischemic brain injury, which may contribute to long-term cognitive decline in this patient population.

Christopher McIntyreAndrew House

This article discusses the clinical utility of midodrine, an oral medication commonly used to prevent and treat low blood pressure during hemodialysis. While small studies show midodrine effectively raises blood pressure and improves symptoms, a large observational study raised safety concerns by linking its use to higher mortality and hospitalizations. However, these observational findings may be biased by confounding, as patients prescribed midodrine are typically sicker and at higher baseline risk for poor outcomes.

Christopher McIntyreAndrew House

This preliminary study evaluated the safety and feasibility of a novel extracorporeal immunomodulatory therapy designed to regulate white blood cells in critically ill patients with severe COVID-19. In twelve patients requiring mechanical ventilation and blood pressure support, the therapy was found to be safe and was associated with a significant 37 percent reduction in the need for blood pressure-boosting medications. These findings support further evaluation of this blood-filtering approach to manage severe inflammation in critically ill patients.

Christopher McIntyreAmit Garg

This study investigated whether tailoring the temperature of dialysis fluid to each patient's body temperature could reduce cardiovascular problems in people receiving long-term dialysis. Researchers found no significant difference in rates of cardiovascular death or hospital admission between patients receiving personalized cooler dialysis and those receiving standard temperature dialysis. The findings suggest that the widespread adoption of cooler dialysis may need to be re-evaluated, as it did not demonstrate the expected cardiovascular benefits in this large trial.

Christopher McIntyre

In eight healthy rats, researchers compared hemodialysis using fluid with a higher or lower sodium concentration and measured blood flow in small vessels and a blood marker of vessel-lining injury. Both groups showed increasing evidence of acute injury to the vessel lining during treatment; the lower-sodium group tended to have poorer small-vessel blood flow, although this difference was not statistically significant. These preliminary findings suggest that the sodium concentration of dialysis fluid may affect small-vessel function even when blood pressure changes are similar.

Christopher McIntyre

This review examines the challenges of choosing the optimal dialysate sodium concentration for patients undergoing hemodialysis. It discusses how to individualize dialysate sodium choices to better address patient symptoms and improve survival outcomes, highlighting that sodium transport and its clinical consequences are still not fully understood.

Christopher McIntyre

Patients undergoing hemodialysis experience significant circulatory stress that can damage small blood vessels and lead to organ injury, even when their overall blood pressure appears stable. This review examines various non-invasive technologies used to monitor microcirculatory function during dialysis treatments. Incorporating these monitoring tools into clinical practice could help healthcare providers detect tissue stress early and personalize dialysis delivery to improve patient outcomes.

Christopher McIntyre

Using advanced sodium magnetic resonance imaging, researchers measured tissue sodium levels in the legs of children with chronic kidney disease and compared them to healthy peers and adults. While overall tissue sodium levels did not differ significantly between healthy children and those with kidney disease, differences emerged when looking at the underlying cause of the kidney disease. Children with glomerular diseases showed elevated tissue sodium levels, whereas those with tubular disorders had reduced levels, with these measurements closely linked to protein loss in the urine and low blood albumin.

Christopher McIntyreAndrew House

The Renal Community Photo Initiative used a participatory photography method called Photovoice to explore resilience and quality of life among adult hemodialysis patients in Ontario, Canada. Participants used various photographic technologies to capture their daily lives and met in focus groups to discuss their experiences and direct how their images should be shared publicly. The project successfully gathered over 1600 images and handwritten logs, establishing a participant-led model to raise public awareness about living with chronic kidney disease.

Christopher McIntyre

This study reports on a twelve-year-old male with a rare genetic kidney disorder called hereditary hypophosphatemic rickets with hypercalciuria, which causes bone pain, fractures, and kidney calcification. Standard phosphate and potassium treatments failed to correct these issues, but adding recombinant human growth hormone, fluconazole, and dietary salt restriction successfully improved the patient's growth, bone pain, and calcium levels. Advanced sodium magnetic resonance imaging also showed normal tissue sodium levels, providing a physiological rationale for the salt restriction.

Christopher McIntyre

This study used a mathematical model of human coronary blood flow to evaluate how narrowing of the large blood vessels and disease of the smaller blood vessels affect heart blood flow and pressure measurements. The simulations showed that while narrowing of the large vessels directly impacts pressure measurements, the presence of small vessel disease also significantly harms overall blood flow. The findings suggest that combining pressure measurements with assessments of small vessel disease is essential for accurate clinical decision-making regarding heart treatments.

Christopher McIntyre

This study evaluated cognitive function in forty-nine patients who had recently started maintenance hemodialysis, comparing them to age- and sex-matched healthy controls. Researchers found that a high proportion of patients experienced cognitive impairment within their first year of starting dialysis, with the most significant deficits observed in verbal skills and reasoning. These findings suggest that cognitive decline is highly prevalent early in the course of hemodialysis and may be related to the treatment itself.

Christopher McIntyreAmit Garg

This study explored the barriers and enablers to delivering exercise programs during dialysis treatments by interviewing healthcare providers and patients across twelve hospitals in Ontario, Canada. The researchers identified key challenges, including a lack of staff training, concerns about workload, and uncertainty regarding patient eligibility and safety. To address these issues, they developed a list of practical solutions and a forty-seven-item feasibility checklist to help clinics successfully implement exercise programs in dialysis units.

Christopher McIntyre

Researchers developed a new computer model of blood flow to study how different anatomical variations in the brain's blood vessels, known as the Circle of Willis, affect brain perfusion during atrial fibrillation. The model showed that missing certain vessel segments significantly increased the risk of low blood flow events, especially at higher heart rates. These findings suggest that individual anatomical differences in brain blood vessels may influence the risk of cognitive decline or dementia in patients with this common heart arrhythmia.

Christopher McIntyreAndrew House

This study evaluated the ability of sodium magnetic resonance imaging to measure the sodium concentration gradient between the inner and outer parts of the kidney, which is a key indicator of kidney function. In healthy volunteers, changes in this gradient measured by the scan closely matched changes in urine concentration after drinking water, and the imaging technique was also shown to be feasible in patients with chronic kidney disease. This non-invasive imaging method could provide a new way to monitor kidney health and function without relying solely on urine tests.

Christopher McIntyre

Using advanced sodium magnetic resonance imaging, researchers measured the concentration of sodium in the skin of patients undergoing hemodialysis and peritoneal dialysis. They found that higher levels of skin sodium were strongly linked to a higher risk of death and major cardiovascular events, independent of age, sex, and blood sodium levels. In hemodialysis patients, higher skin sodium was specifically associated with the sodium concentration of the dialysis fluid, low blood albumin, and a history of congestive heart failure.

Christopher McIntyre

This review examines computational cardiology tools used to study cardiac arrhythmias across different species, including humans, rabbits, and mice. By integrating experimental data into multi-scale electro-anatomical models, researchers can simulate how sub-cellular ion channels and tissue scarring affect electrical propagation and electrocardiogram readings. The work highlights how these computer models can be personalized to improve our understanding of heart rhythm disorders and translate findings from animal models to human treatments.

Christopher McIntyre

Using a newly developed small animal model, researchers monitored the microvasculature of healthy rats in real time during hemodialysis. They found that even without fluid removal, the hemodialysis procedure caused significant systemic hemodynamic disturbances and acutely reduced blood flow in skeletal muscle microcirculation. This model demonstrates that hemodialysis itself can directly impair microvascular perfusion, providing a new way to study and prevent dialysis-induced ischemic organ injury.

Louise MoistChristopher McIntyre

Researchers followed eight patients undergoing hemodialysis through the creation of an upper-arm arteriovenous fistula and tracked changes in their heart structure using magnetic resonance imaging. They found that all patients experienced an increase in the muscle mass of the heart's main pumping chamber, and most experienced a decrease in the chamber’s ability to pump blood effectively within the first year. These changes in heart structure are concerning because increased heart muscle mass is linked to a higher risk of health problems and death in people with kidney disease.