The use of digital magnification to reduce radiation dose in the cardiac catheter laboratory

Objectives: To audit whether using magnification of images by use of a large viewing screen using digital matrix magnification which enlarges the image by 33% without using the X-ray machine zoom magnification protocols on a Siemens Artis Zee X-ray machine in a cardiac catheter laboratory results in a reduction of kerma–area product (KAP) for both diagnostic and interventional procedures. This reduction was predicted in an in vitro study in our laboratory, which has previously shown a 20.4% reduction in KAP. Methods: A retrospective analysis was conducted of the radiation exposure to compare the measured KAP recorded during the period when conventional magnification with automatic brightness and dose control was used on a Siemens Artis Zee X-ray machine with a flat panel detector and when magnification settings were avoided by using a large screen to enlarge and project a non-magnified image by digital magnification. The analysis was carried out for patients having a diagnostic coronary angiogram and those having an interventional coronary procedure. Results: For diagnostic coronary angiograms the median KAP per procedure in the period using conventional magnification was 2124.5 µGy.m2 compared to 1401 µGy.m2 when image matrix magnification was used, a 34% reduction (p < 0.0001). For interventional coronary procedures, the median KAP per procedure in the period using conventional magnification was 3791 µGy.m2 compared to 2568.5 µGy.m2 when image matrix magnification was used, a 32% reduction (p < 0.0001). Conclusion: Avoiding using conventional magnification in the cardiac catheter laboratory and using a large screen to magnify images was associated with a statistically significant greater than 30% reduction in KAP. Advances in knowledge: This paper is the proof in clinical practice of a theoretical conclusion that radiation dose (KAP) is reduced by use of Image matrix magnification using a large viewing screen without the need to use X-ray tube magnification without significant loss of image resolution in interventional cardiology. The same approach will be useful in interventional radiology.

Functional assessment of coronary blood flow as contemporary method for optimizing results of percutaneous coronary interventions in patients with ischemic heart disease

Coronary angiography is still the ‘gold standard’ in assessing the severity of stenotic lesions of the coronary arteries in the catheter laboratory. However, it is often difficult to identify the hemodynamic significance of one or another coronary artery stenosis, which is especially difficult in the case of borderline lesions with a coronary artery stenosis of 40–70 % according to angiography. It is important to note that the results of performed PCI are still largely assessed only on the basis of control angiographic data. This is due to the fact that the largest difference between angiography and FFR is in the intermediate range, and in general there is much less variation between angiography and fractional blood flow reserve (FFR) in the severe and mild lesions. However, the results of studies evaluating FFR after PCI showed a wide range of FFR values after satisfactory results of stenting according to angiography data. This additionally confirms the thesis that only one angiography is limited in determining the ischemic boundaries after PCI, and the level of FFR values after PCI is directly related to the results in the long-term period. Percutaneous coronary interventions under the control of FFR allows the operator to improve the results of endovascular treatment of coronary lesions in patients with coronary heart disease. The use of FFR in a catheter laboratory contributes to an increase in the clinical and economic efficiency of procedures, which is achieved due to the fact that the determination of FFR before PCI can significantly reduce the number of stents implanted during PCI, as well as to avoid unnecessary PCI stages in the treatment of patients with lesions of the LMCA. In addition, FFR allows to timely optimize the results of suboptimal PCI, as well as to reduce the frequency of main adverse cardiovascular events in the long-term period.

Association of Kidney Disease, Potassium, and Cardiovascular Risk Factor Prevalence with Coronary Arteriosclerotic Burden, by Sex

The present study aimed to determine the relationship between the prevalence of cardiovascular risk factors and the number and severity of coronary artery atherosclerotic lesions obtained by coronary angiography. We reviewed and analyzed 1642 records from consecutive patients at the Catheter Laboratory of Talca Regional Hospital in Chile between March 2018 and May 2019. Patients were stratified according to the presence and severity of atherosclerotic lesions: 632 (38.5%) had no lesions or <30% stenosis and 1010 (61.5%) had at least one coronary atherosclerotic lesion with ≥30% stenosis (CALS-30). CALS-30 was more frequent in males, smokers, and patients with diabetes and/or hypertension (all p-values < 0.02). Serum potassium, glycaemia, creatinine and glomerular filtration rates were also associated with CALS-30 (all p-values < 0.01) in males. The age and the proportion of males with CALS-30 increased with the number of risk factors (p-values for trends < 0.001). Our results showed a stronger association between the accumulation of risk factors and CALS-30 in women than in men. Serum potassium levels were inversely associated with CALS-30 in men but not in women.

Mobile stroke unit in the UK healthcare system: avoidance of unnecessary accident and emergency admissions

<sec id="s1"> Aims: The aim of the study was to explore the benefit of a mobile stroke unit (MSU) in the UK National Health Service (NHS) for reduction of hospital admissions. </sec> <sec id="s2"> Methods: Prospective cohort audit observation with dispatch of the MSU in the East of England Ambulance Service was conducted. Emergency patients categorised as code stroke and headache were included from 5 June to 18 December 2018. Rate of avoided admission to the accident and emergency (A&E) department, rate of admission directly to target ward and stroke management metrics were assessed. </sec> <sec id="s3"> Results: In 116 MSU-treated patients, the following diagnoses were made: acute stroke, n = 33 (28.4%); transient ischaemic attacks, n = 13 (11.2%); stroke mimics, n = 32 (27.6%); and other conditions, n = 38 (32.8%). Pre-hospital thrombolysis was administered to eight of 28 (28.6%) ischaemic stroke patients. Pre-hospital diagnosis avoided hospital admission for 29 (25.0%) patients. As hospital treatment was indicated, 35 (30.2%) patients were directly triaged to the stroke unit, one patient (0.9%) even directly to the catheter laboratory. Thus, only 50 (43.1%) patients required transfer to the A&E department. Moreover, the MSU enabled thrombolysis with a median dispatch-to-needle time of 42 mins (interquartile range, 40‐60). </sec> <sec id="s4"> Conclusion: This first deployment of an MSU in the UK NHS demonstrated improved triage decision-making for or against hospital admission and admission to the appropriate target ward, thereby reducing pressure on strained A&E departments. </sec>

Review of High Relative Humidity in Catheter Laboratory of a Private Hospital and a Low Energy Consuming Solution

The Relative Humidity in a Catheter Laboratory is desirous to be controlled within a range of 30 to 65% RH. A maximum Relative Humidity (RH) fluctuation of up to 70% is tolerated. A case study is presented whereby a high RH of up to 80% RH has been recorded in the examination room of a Catheter Laboratory (CathLab) in a local Hospital. The conditioned air to the CathLab is supplied through an existing dedicated Chilled Water Air Handling Unit. Two (2) solutions were considered and the technical and commercial comparisons carried out. The first option is an inline dehumidifier system and the second option is to install a portable standalone dehumidifier inside the CathLab examination room. Solutions to address the high Relative Humidity have to be carefully considered as the introduction of in-line dehumidifiers contribute to higher energy consumption. The latter was selected based on commercial reasons. Three (3) weeks of RH monitoring via the building’s Integrated Building Management System (IBMS) was carried out. The readings measured show a drastic reduction in RH to a mean of about 60% RH which meets the end user’s requirement. The cost for the second option was also found to be much lower at about 10% of the first option.

RELATIONSHIP BETWEEN DOOR-TO-BALLOON TIME AND CLINICAL EXPERIENCE LEVEL OF EMERGENCY DEPARTMENT PHYSICIANS

Background: This study aimed to investigate the relationship between the experience level of physicians who initially make a clinical diagnosis of patients with ST segment elevation myocardial infarction in the emergency department and door-to-balloon time (DBT). Material and methods: Between January and December 2018, the research group was selected randomly among 522 patients with ST elevation myocardial infarction who were immediately treated in the catheter laboratory. Angiography images were monitored from the patients’ records in the catheter laboratory. The time of admission to the emergency room was obtained using the hospital registration system. The experience level of physicians who initially clinically diagnosed patients in the emergency department was divided into three groups: medical practitioner (who did not receive emergency training), assistant physician (undergoing emergency medicine training), and emergency medicine specialist. Results: The study included 522 patients who underwent primary percutaneous intervention due to ST segment elevation myocardial infarction. The mean age was lower, and cardiogenic shock and mortality rates were lower in the group with DBT<60 /min compared with the group with DBT>60/min. In the expert group, the mean DBT was lower, but the cardiogenic shock and mortality rates were higher (p<0.05). Conclusions: The duration of DBT decreases as the experience level of the emergency physician increases, but randomization is required to determine its clinical benefit

How to select patients requiring coronary revascularisation using coronary physiology

The coronary angiogram is an indicator of flow limiting coronary artery disease but coronary physiology at the time of angiography is vital in assessing the true functional significance of coronary artery disease. With advances in guidewire technology and the greater use of physiology within the catheter laboratory, there is now a slow evolution of physiological indices in being able to reliably assess the functional significance of individual lesions and also the adequacy of revascularization in a growing range of clinical scenarios. As co-registration of physiology with the angiogram and intravascular imaging will become easier, we will find ourselves increasingly in an era of ‘Precision PCI’.