Endomyocardial biopsy remains the gold standard for cardiac cellular rejection surveillance after heart transplantation. We studied a novel non-invasive index of left ventricular relaxation to detect cardiac cellular rejection in paediatric heart transplant patients.

This is a single-centre retrospective study of paediatric heart transplant patients who underwent endomyocardial biopsy from June 2014 to September 2021. Left ventricular relaxation index was calculated as the sum of diastolic tissue Doppler imaging velocities (E) of the left ventricular lateral, septal, and posterior walls divided by the percentage of the left ventricular posterior wall thinning by M-mode. Statistical analysis included t-tests and Mann-Whitney tests to compare means and medians between treatment and non-treatment groups. We used the cut-off with the maximum Youden index to compare the sensitivity and specificity of left ventricular relaxation index to detect rejection.

The study included 65 patients who underwent 246 cardiac catheterizations and endomyocardial biopsies. Out of 246, 192 procedures were included and 54 were excluded due to recent transplants or lack of echocardiographic data. A total of 114 demonstrated Grade 0R, 68 Grade 1R, 8 Grade 2R, and 2 Grade 3R allograft rejection. The difference in mean left ventricular relaxation index between treatment versus non-treatment groups (2R, 3R vs. 0R, 1R) was not statistically significant (p = 0.917). A left ventricular relaxation index cut-off of 0.73 had the highest Youden index with good sensitivity (100%) and poor specificity (23%) for detecting rejections with grades 2R and 3R.

Left ventricular relaxation index, a novel index of left ventricular relaxation, was not a sensitive or specific predictor of cardiac cellular rejection in paediatric heart transplants.

Aggregation of phosphorylated tau (pTau) is a hallmark feature of Alzheimer’s disease (AD). Novel assays now allow pTau to be measured in plasma. Elevated plasma pTau predicts subsequent development of AD, cortical atrophy and AD-related pathologies in the brain. We aimed to determine whether elevated pTau is associated with cognitive functioning in older adults prior to the development of dementia.

Independently living older adults (N = 48, mean age = 70.0 years; SD = 7.7; age range 55-88 years; 35.4% male) free of dementia or clinical stroke were recruited from the community and underwent blood draw and neuropsychological assessment. Plasma was assayed using the Quanterix Simoa® pTau-181 V2 Advantage Kit to quantify pTau-181 levels and APOE genotyping was conducted on the blood cell pellet fraction obtained from plasma separation. Global cognition was assessed using the Dementia Rating Scale-2 (DRS-2) and executive function was assessed using the Stroop, D-KEFS-2 Fluency, and Trails Making Test. Diagnosis of mild cognitive impairment (MCI) was determined based on overall neuropsychological performance. Participants were diagnosed as MCI if they scored >1 SD below norm-referenced values on 2 or more tests within a domain (language, executive, memory) or on 3 tests across domains.

Multiple linear regression analysis revealed a significant negative association between plasma pTau-181 levels and DRS-2 (B = -2.57, 95% CI (-3.68, -1.47), p <.001), Stroop Color-Word score (B = -2.64, 95% CI (-4.56, - 0.71), p = .009) and Fruits and Vegetables Fluency (B = -1.67, 95% CI (-2.84, -0.49), p = .007), adjusting for age, sex, education and APOE4 status. MCI diagnosis was determined for 43 participants, of which 8 (18.6%) met criteria. Logistic regression analysis revealed that pTau-181 levels are associated with increased odds of MCI diagnosis (OR = 2.18, 95% CI (1.01, 4.68), p = .046), after accounting for age, sex, education and APOE4 status.

Elevated plasma pTau-181 is associated with worse cognition, particularly executive function, and predicts MCI diagnosis in older adults. Higher plasma pTau-181 was associated with increased odds of MCI diagnosis. Detection of pTau-181 in plasma allows a novel, non-invasive method to detect burden of one form of AD pathology. These findings lend support to the use of plasma pTau-181 as a valuable marker in detecting even early cognitive changes prior to the development of AD. Additional longitudinal studies are warranted to explore the prognostic value of plasma pTau-181 over time.

Blood pressure variability (BPV), independent of traditionally targeted average blood pressure levels, is an emerging vascular risk factor for stroke, cerebrovascular disease, and dementia, possibly through links with vascular-endothelial injury. Recent evidence suggests visit-to-visit (e.g., over months, years) BPV is associated with cerebrovascular disease severity, but less is known about relationships with short-term (e.g., < 24 hours) fluctuations in blood pressure. Additionally, it is unclear how BPV may be related to angiogenic growth factors that play a role in cerebral arterial health.

We investigated relationships between short-term BPV, white matter hyperintensities on MRI, and levels of plasma vascular endothelial growth factor (VEGF) in a sample of community-dwelling older adults (n = 57, ages 55-88) without history of dementia or stroke. Blood pressure was collected continuously during a 5-minute resting period. BPV was calculated as variability independent of mean, a commonly used index of BPV uncorrelated with average blood pressure levels. Participants underwent T2-FLAIR MRI to determine severity of white matter lesion burden. Severity of lesions was classified as Fazekas scores (0-3). Participants also underwent venipuncture to determine levels of plasma VEGF. Ordinal logistic regression examined the association between BPV and Fazekas scores. Multiple linear regression explored relationships between BPV and VEGF. Models controlled for age, sex, and average blood pressure.

Elevated BPV was related to greater white matter lesion burden (i.e., Fazekas score) (systolic: OR = 1.17 [95% CI 1.01, 1.37]; p = .04; diastolic: OR = 2.47 [95% CI 1.09, 5.90]; p = .03) and increased levels of plasma VEGF (systolic: ß = .39 [95% CI .11, .67]; adjusted R2 = .16; p = .007; diastolic: ß = .48 [95% CI .18, .78]; adjusted R2 = .18; p = .003).

Findings suggest short-term BPV may be related to cerebrovascular disease burden and angiogenic growth factors relevant to cerebral arterial health, independent of average blood pressure. Understanding the role of BPV in cerebrovascular disease and vascular-endothelial health may help elucidate the increased risk for stroke and dementia associated with elevated BPV.