Stress Echocardiography in the Follow-Up of Young Patients with Repaired Aortic Coarctation.

Background: Aortic coarctation (CoA) is a congenital heart disease affecting 5-8% of patients, with long-term complications persisting despite successful correction. Stress echocardiography (SE) is increasingly used for evaluating cardiac function under stress, yet its role in repaired CoA remains under-explored. Objective: This study aimed to assess the predictive value of SE and myocardial strain in repaired CoA patients with a history of hypertension without significant gradients or with borderline gradients at rest. Methods: Between June 2020 and March 2024, we enrolled 35 consecutive CoA patients with successful repairs and either a history of hypertension or borderline Doppler gradients. Baseline and peak exercise echocardiographic measurements, including left ventricular mass index (LVMi) and global longitudinal strain (LVGLS), were recorded. Patients were followed for up to 4 years. Results: At baseline, the positive SE group had higher systolic blood pressure (SBP) and diastolic blood pressure (DBP) compared to the negative SE group. The positive SE group also exhibited significantly higher basal and peak trans-isthmic gradients. Positive SE was found in 45.7% of patients, with 68.7% of these requiring re-intervention during follow-up. A peak trans-isthmic gradient > 61 mmHg during exercise predicted recoarctation with 100% sensitivity and 71% specificity (AUC = 0.836, p < 0.004). Conclusions: SE identifies at-risk patients post-CoA repair, aiding in early intervention. A peak trans-isthmic gradient > 61 mmHg during exercise is a strong predictor of recoarctation. These findings support incorporating SE into routine follow-up protocols for CoA patients, particularly those with a history of hypertension and borderline gradients, to improve long-term outcomes and quality of life.

Fast Chemical Contrast by X-ray Fluorescence Intensity Ratio Detection.

We describe a protocol for efficient detection of the chemical state of an element based on X-ray emission (fluorescence) spectroscopy using a Bragg optics spectrometer. The ratio of intensities at two appropriately chosen X-ray emission energies is a self-normalized quantity largely free of experimental artifacts and can thus be recorded with high accuracy. As the X-ray fluorescence lines are chemically sensitive, the intensity ratio identifies the chemical state. Differences between chemical states in spatially inhomogeneous or temporally evolving samples can be identified already with low numbers of photon events. This reduces the time required for data acquisition by 2 orders of magnitude as compared to recording a full spectrum.