Temporal variations of spring hydrochemistry as clues to the karst system behaviour: an example of Louros Catchment.

Effectively managing water resources in karst systems requires a thorough understanding of their general conduit network along with their seasonal dynamics. Their investigation has involved well construction or several advanced natural tracer data, most of which are not always available. Hence, this work showcases a pragmatic approach that makes use of basic hydrochemical variables of springs with coarse temporal resolution in characterising a karst system. In this study's example, physicochemical variables like major ion concentrations/ratios, Electrical Conductivity (EC), pH and water temperature (Tw) were measured on 20-day basis for a hydrological year at the Louros Catchment, Greece. We further performed the frequency distribution and variation analysis of EC and Tw, principal component analysis (PCA), scatter plots of carbonate ions vs sulphate and hydrochemographs to determine relevant hydrochemical processes and hydrogeological features. PCA and the scatter plots showed that the simple-type upper karst level is entirely dominated by carbonate dissolution, whereas the complex-type middle and lower levels also involve gypsum and dolomite dissolution. Presence of mixing between karst units was also detected. EC and Tw analyses revealed the degree of karstification of different units and relative depths of flow systems. Hydrochemographs reflected the seasonality of limestone and gypsum dissolution's contributions linked to the dominant flow type (conduit vs diffuse). This study thus was able to demonstrate the usefulness of such holistic hydrochemical analyses to better understand karst systems. Given their cost-effectiveness, they can be easily applied to any understudied karst system worldwide.

Assessment of groundwater vulnerability to nitrates using the GIS-based DRASTIC and SI methods: a case study in Zacharo area, Greece.

A vulnerability assessment of the aquifers in the agricultural area of Zacharo in SW, Peloponnese, Greece, was conducted using the DRASTIC index and the susceptibility index (SI). Sensitivity analysis was conducted and thematic maps for each parameter were generated to analyse the impact of individual parameter on the collective groundwater vulnerability. Results derived from the DRASTIC and SI maps revealed that the extremely highly vulnerable zones are concentrated at three coastal sites in the western part of the study area. Data from these maps also indicate low vulnerability areas throughout the eastern part of the region. The distribution of nitrate concentrations in groundwater is better correlated with the DRASTIC (79.2%) compared to SI (60.2%). Neither method takes into consideration the impact of dilution and nitrate to ammonium reduction, on the nitrate content of groundwater, thus overestimating the vulnerability index. Moreover, the SI method overestimates the impact of olive groves' land use type on the susceptibility index, thus resulting to a lower correlation with the observed nitrate concentrations.

Ticagrelor potentiates cardioprotection by remote ischemic preconditioning: the ticagrelor in remote ischemic preconditioning (TRIP) randomized clinical trial.

OBJECTIVE: Remote ischemic preconditioning (RIPC) reduces periprocedural myocardial injury (PMI) after percutaneous coronary intervention (PCI) through various pathways, including an adenosine-triggered pathway. Ticagrelor inhibits adenosine uptake, thus may potentiate the effects of RIPC. This randomized trial tested the hypothesis that ticagrelor potentiates the effect of RIPC and reduces PMI, assessed by post-procedural troponin release. METHODS: Patients undergoing PCI for non-ST elevation acute coronary syndromes were 1:1 randomized to ticagrelor (TG-Group) or clopidogrel (CL-Group). Within each treatment, patients were 1:1 randomized to a RIPC (RIPC-Group) or a control group (CTRL-Group). The primary endpoint was the difference between post- and pre-procedural troponin at 24 h following PCI, termed deltaTnI. RESULTS: During a 12-month period, 138 patients were included in the study (34 in the CL-CTRL group, 34 in the TG-CTRL group, 35 in the CL-RIPC group, and 35 in the TG-CTRL group). There was a significant difference in deltaTnI between the study groups [ TG-RIPC:0.04 (0-0.16), CL-CTRL:0.10 (0.03-0.43), CLRIPC:0.11 (0.03-0.89), and TG-CTRL:0.24 (0.06-0.47); p = 0.007]. Eight patients (22.9%) in the TG-RIPC group developed type 4a myocardial infarction (MI), compared to 14 (40%) in the CL-RIPC group, 13 (38.2%) in the CL-CTRL group, and 19 (55.9%) in the TG-CTRL group (p = 0.048). A significant interaction between antiplatelet group allocation and RIPC on deltaTnI was observed [F (1,134) = 7.509; p = 0.007]. In multivariate analysis, the interaction between RIPC and ticagrelor treatment was independently associated with a lower incidence of Type 4a MI. CONCLUSION: Our results demonstrate an interaction between ticagrelor and RIPC, which may potentiate the cardioprotective effects of RIPC during PCI by reducing PMI.

Ping-pong guide catheter technique for facilitating antegrade crossing of a chronic total occlusion.

A 60-year-old man was referred for percutaneous coronary intervention of a proximal left circumflex (Cx) chronic total occlusion (CTO) with distal filling via epicardial collaterals from the left anterior descending (LAD) artery.

Triple-Access Retrograde Chronic Total Occlusion Intervention Through Vein Graft and Epicardial Collaterals.

Based on the patient's symptoms and examination, a decision was made to recanalize his totally occluded RCA via retrograde approach through the SVG to the OM. Due to inadequate visualization of the epicardial collaterals and distal RCA via SVG, triple-access was used and injection via left main. In selected CTO cases, triple access may facilitate the retrograde approach, allowing optimal collateral visualization.

Right arm distal transradial (snuffbox) access for coronary catheterization: Initial experience.

BACKGROUND: Distal transradial access (dTRA) by the snuffbox approach for coronary catheterization has emerged as an alternative to the classic forearm TRA with certain advantages and limitations.The aim of this study was to evaluate the effectiveness and safety of the dTRA exclusively from the right arm. METHODS: Forty-nine consecutive patients (31 males and 18 females, mean age 64 ± 12 years), who were candidates for coronary catheterization in two cath laboratory centers, regardless of the indication, were recruited. Right dTRA was exclusively used. Radial artery patency both at the forearm and at the snuffbox region was evaluated 24 h after successful hemostasis by triplex ultrasonography. All complications were recorded until 24 h after the procedure. RESULTS: The indication for catheterization was an acute coronary syndrome in 24.5%, stable coronary artery disease in 22.4%, and other reasons in 53.1%. The overall failure attempt incidence was 10.2% and the mean puncture time 3.9 ± 4.1 min. Angiography only was performed in 81.8% and angiography followed by percutaneous coronary intervention in 18.2% of the patients. Manual hemostasis was applied in 63.6% of the patients, which had a significantly shorter duration than device hemostasis (11 ± 7 versus 198 ± 42 min, p < 0.001). No distal or forearm radial artery occlusion was observed on triplex ultrasonography 24 h after successful hemostasis. No major complications were recorded. CONCLUSIONS: This two-center study, utilizing exclusively the right dTRA, provides further data regarding the snuffbox approach in an all-comers population. Further worldwide reports will elucidate new aspects of the technique.

Dissection Re-entry Technique: How is it Really Looking?

Dissection re-entry is a widely used technique in many chronic total occlusion centers. This account of a failed re-entry attempt provides in vivo photographic evidence of how the vessel looked after such an attempt. Operators are advised to keep dissection of subintimal space and hematoma limited and use dedicated materials and techniques for controlled re-entry.

Distal Versus Traditional Radial Approach for Coronary Angiography.

PURPOSE: The aim of this study was to evaluate the efficacy and safety of distal radial (DR) versus traditional radial (TR) approach during coronary angiography. METHODS: Two hundred patients scheduled to undergo transradial coronary angiography were randomized between the two approaches. Primary endpoint of the study was switching to another access site due to inability of successful target artery cannulation. Secondary endpoints were time to cannulation, total procedure duration, number of attempts, number of skin punctures and duration of manual hemostasis. Secondary safety endpoints were the rate of moderate or severe spasm, arm hematoma EASY class III or more and radial artery occlusion at discharge. Quality of life endpoint was the patient's preference of cannulation method at 30 days. RESULTS: The primary endpoint was met in 30 patients (30%) from the DR group and 2 patients (2%) from the TR group (p < 0.001). The time of cannulation was longer in the DR group compared to the TR group (269 ±â€¯251 s vs 140 ±â€¯161 s, p < 0.001), but this did not affect the total procedural duration (925 ±â€¯896 s vs 831 ±â€¯424 s, p = 0.494). The number of attempts and the number of skin punctures were more in the DR group compared to the TR group (6.8 ±â€¯6.2 vs 3.4 ±â€¯4.5, p < 0.001 and 2.4 ±â€¯1.7 vs 1.6 ±â€¯1.2, p < 0.001, respectively). However, DR treated patients had faster manual hemostasis time compared to TR treated patients (568 ±â€¯462 s vs 841 ±â€¯574 s, p = 0.002). There were no differences recorded in the safety endpoints of moderate or severe spasm, EASY grade III or more radial hematomas or the incidence of radial artery occlusion after the procedure. Patients' preference to the randomized puncture sites was the same (79% vs 85%, p = 0.358). CONCLUSION: Distal radial approach is associated with lower successful cannulation rates and shorter manual hemostasis time compared to the traditional radial approach.

Compartment Syndrome: A Rare and Frightening Complication of Transradial Catheterization.

The compartment syndrome is a severe complication of transradial approach and can be prevented by prompt treatment of forearm hematoma; otherwise, fasciotomies are urgent.