Publications by authors named "Grigoris V Karamasis"

Background And Aims: Guidelines suggest non-traumatic out-of-hospital cardiac arrest (OHCA) be conveyed to cardiac arrest centres (CAC). We hypothesised that (a) a pre-hospital conveyance algorithm based on initial presenting rhythm following OHCA is feasible and (b) that would demonstrate survival advantage.

Methods: This observational pilot study included all consecutive patients with OHCA from suspected cardiac aetiology from the county of Essex, United Kingdom from April 2022-April 2023.

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Introduction: Transcatheter aortic valve replacement (TAVR) is increasingly in demand for treating severe aortic stenosis in a variety of surgical risk profiles. This means increasing wait times and elevated morbidity and mortality on the waitlist. To address this, we developed the SWIFT TAVR algorithm to prioritize patients based on clinical risk and reduce wait times.

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Background: Coronary computed tomography angiography (CCTA) in patients with post-coronary artery bypass graft (CABG) has a high diagnostic accuracy for visualization of grafts. Invasive coronary angiography (ICA) in patients with CABG is associated with increased procedural time, contrast agent administration, radiation exposure, and complications, compared with non-CABG patients. The aim of this multicenter, randomized controlled trial was to compare the strategy of CCTA-guided ICA versus classic ICA in patients with prior CABG.

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Article Synopsis
  • * Out of 130 patients with definite ST, 45 underwent ICI, and the analysis found that ICI-guided management improved survival rates free of cardiac death or target lesion revascularization (CD-TLR) at 2 years to 93% compared to 73% for those not guided by ICI.
  • * The results suggest that ICI can significantly influence treatment decisions, leading to better outcomes in patients with ST, particularly by identifying the main mechanisms causing thrombosis.
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  • A new method called intracoronary continuous thermodilution is being studied to measure coronary blood flow (Q) and resistance (R) without needing special tools like pressure wires or microcatheters, using standard coronary angiograms.
  • The validation of this technique was conducted on a group of 62 patients across two medical centers, comparing flow and resistance measurements during rest and increased blood flow (hyperemia).
  • The study found strong correlations between the traditional and angiography-derived measurements for both flow and resistance, suggesting the new method is reliable for assessing coronary function.
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Objective: Observational studies have shown that the management of patients with cardiogenic shock (CS) by dedicated multidisciplinary teams improves clinical outcomes. Nevertheless, these studies reflect a specific organizational setting with most patients being transferred from referring hospitals, hospitalized in cardiac intensive care units (ICU), or treated with mechanical circulatory support (MCS) devices. The purpose of this study was to document the organization and outcomes of a CS team offering acute care in an all-comer population.

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: To assess whether hydrostatic pressure gradients caused by coronary height differences in supine versus prone positioning during invasive physiological stenosis assessment affect resting and hyperaemic pressure-based indices or coronary flow. : Twenty-three coronary stenoses were assessed in twenty-one patients with stable coronary artery disease. All patients had a stenosis of at least 50% visually defined on previous coronary angiography.

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SARS-CoV-2 is responsible for the global coronavirus disease 2019 (COVID-19) pandemic. While the cardiovascular effects of COVID-19 have been thoroughly described, there are limited published studies in the literature establishing a connection between spontaneous coronary artery dissection (SCAD) and COVID-19. Cardiovascular manifestations include, among others, myocarditis, acute myocardial infraction, and thrombosis.

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Background: The assessment of coronary microvascular dysfunction (CMD) using invasive methods is a field of growing interest, however the preferred method remains debated. Bolus and continuous thermodilution are commonly used methods, but weak agreement has been observed in patients with angina with non-obstructive coronary arteries (ANOCA). This study examined their agreement in revascularized acute coronary syndromes (ACS) and chronic coronary syndromes (CCS) patients.

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An 82-year-old male patient with severe, symptomatic aortic stenosis was referred for transcatheter aortic valve implantation.

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The optimal duration of DAPT after complex PCI remains under investigation. The purpose of this systematic review and meta-analysis was to explore the safety and efficacy of a one-month therapy period versus a longer duration of DAPT after complex PCI. We systematically screened three major databases, searching for randomized controlled trials or sub-analyses of them, which compared shortened DAPT (S-DAPT), namely, one month, and longer DAPT (L-DAPT), namely, more than three months.

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Continuous Thermodilution is a novel method of quantifying coronary flow (Q) in mL/min. To account for variability of Q within the cardiac cycle, the trace is smoothened with a 2 s moving average filter. This can sometimes be ineffective due to significant heart rate variability, ventricular extrasystoles, and deep inspiration, resulting in a fluctuating temperature trace and ambiguity in the location of the "steady state".

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Article Synopsis
  • * A study involving 315 patients found that after 1 year, only 4.9% experienced serious events like cardiac death or stent thrombosis, which was better than the pre-set safety target.
  • * The results indicate that a 1-month DAPT is sufficient for patients with stable angina, and some acute coronary syndrome patients had DAPT extended to 3 months, with very low rates of complications.
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Chronic total occlusions (CTOs) represent the most complex subset of coronary artery disease and therefore careful planning of CTO percutaneous coronary recanalization (PCI) strategy is of paramount importance aiming to achieve procedural success, and improve patient's safety and post CTO PCI outcomes. Intravascular imaging has an essential role in facilitating CTO PCΙ. First, intravascular ultrasound (IVUS), due to its higher penetration depth compared to optical coherence tomography (OCT), and the additional capacity of real-time imaging without need for contrast injection is considered the preferred imaging modality for CTO PCI.

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Intracoronary imaging (ICI) modalities, namely intravascular ultrasound (IVUS) and optical coherence tomography (OCT), have shown to be able to reduce major adverse cardiovascular events in patients undergoing percutaneous coronary intervention (PCI). Nevertheless, patients with ST-segment elevation myocardial infarction (STEMI) have been practically excluded from contemporary large randomized controlled trials. The available data are limited and derive mostly from observational studies.

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The landscape of interventional cardiology is ever evolving. Contemporary practice has shifted from a stenosis-centred approach to the total characterisation of both the epicardial and microcirculatory vessels. Microcirculatory dysfunction plays an important role in the pathophysiology of acute and chronic coronary syndromes, and characterisation of the microcirculation has important clinical consequences.

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Radial access has largely substituted femoral access for coronary interventions. Nevertheless, the femoral artery remains indispensable for gaining access to structural and complex percutaneous coronary interventions such as transcatheter aortic valve implantation and chronic total occlusion interventions, respectively. Ultrasound-guided femoral puncture is a broadly available, inexpensive, and relatively easy-to-learn technique.

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Wall shear stress (WSS) estimated in models reconstructed from intravascular imaging and 3-dimensional-quantitative coronary angiography (3D-QCA) data provides important prognostic information and enables identification of high-risk lesions. However, these analyses are time-consuming and require expertise, limiting WSS adoption in clinical practice. Recently, a novel software has been developed for real-time computation of time-averaged WSS (TAWSS) and multidirectional WSS distribution.

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Background: Percutaneous coronary intervention (PCI) for coronary chronic total occlusion (CTO) has been performed for the improvement of symptoms and quality of life in patients with stable angina. The ORBITA study demonstrated the role of the placebo effect in contemporary PCI in non-CTO chronic coronary syndromes. However, the benefit of CTO PCI beyond that of a placebo has not been demonstrated.

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Background: Randomised studies of percutaneous coronary intervention (PCI) in patients with chronic total occlusion (CTO) have shown inconsistent outcomes, suggesting incomplete understanding of this cohort and their coronary physiology. To address this shortcoming, we designed a prospective observational study to measure the recovery of absolute coronary blood flow following successful CTO PCI Aims: We sought to identify patient and procedural characteristics associated with a favourable physiological outcome after CTO PCI.

Methods: Consecutive patients with a CTO subtending viable myocardium underwent PCI utilising contemporary techniques and the hybrid algorithm.

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