108 Atrial fibrillation effects on coronary perfusion across the different myocardial layers: a computational analysis

Aims Atrial fibrillation (AF) patients may present ischaemic chest pain in the absence of classical obstructive coronary disease. Among the possible causes, the direct haemodynamic effect exerted by the irregular arrhythmia has not been studied in detail. Methods and results A computational fluid dynamics analysis was performed by means of a 1D-0D multiscale model of the entire human cardiovascular system, characterized by a detailed mathematical modelling of the coronary arteries and their downstream distal microcirculatory districts (subepicardial, midwall, and subendocardial layers). Three mean ventricular rates were simulated in both sinus rhythm (SR) and AF: 75, 100, 125 b.p.m. We conducted inter-layer and inter-frequency analysis of the ratio between mean beat-to-beat blood flow in AF compared to SR (Q¯AP/Q¯SR Inter-layer analysis showed that, for each simulated ventricular rate, Q¯AP/Q¯SR progressively decreased from the epicardial to the endocardial layer in the distal left coronary artery districts (P-values < 0.001 for both left anterior descending artery—LAD, and left circumflex artery—LCx), while this was not the case for the distal right coronary artery (RCA) district. Inter-frequency analysis showed that, focusing on each myocardial layer, Q¯AP/Q¯SR progressively worsened as the ventricular rates increased in all investigated microcirculatory districts (LAD, LCx, and RCA) (P-values < 0.001 for all layer-specific comparisons). Conclusions AF exerts direct haemodynamic consequences on the coronary microcirculation, causing a reduction in microvascular coronary flow particularly at higher ventricular rates; the most prominent reduction was seen in the subendocardial layers perfused by left coronary arteries (LAD and LCx).

608 The VCX Index: a novel haemodynamic quantification of mitral regurgitation

Percutaneous edge-to-edge mitral valve (MV) repair is extensively used in different pathological MV conditions. Randomized controlled trials have evaluated the role of this technique in both primary (organic) and secondary (functional) mitral regurgitation (MR). Furthermore, recent analyses of these studies have shown the relevance of echocardiographic patient selection in the functional setting of MR, differentiating proportionate MR from disproportionate MR according to the degree of the effective regurgitant orifice area (EROA) related to the left ventricular volume. The haemodynamic impact of MR cannot be univocally measured by echocardiography alone and the aim of our study was to determine how invasive LAP monitoring during percutaneous edge-to-edge MV repair can predict long-term procedural success on top of the echocardiographic assessment by introducing the VCX INDEX and identifying haemodynamic variables with direct influence on filling pressures. The VCX INDEX, reflecting the impact of MR, is calculated by dividing the difference between v wave (ventricular systole in the left atrial pressure, LAP, or in the pulmonary capillary wedge pressure, PCWP, waveform) and the mean minimum LAP or mean minimum PCWP (mean between minimum LAP or minimum PCWP, x wave, and a/c wave) by systolic arterial pressure (SAP): (v wave – mean minimum LAP or mean minimum PCWP)/SAP. 85 patients at our centres underwent invasive intracardiac pressure monitoring either measuring LAP during percutaneous edge-to-edge MV repair or PCWP during right heart catheterization. Median VCX INDEX was 0.1 (Q1 0.05, Q3 0.16). The study population was further analysed according to the echocardiographic aetiology of MR: in the organic MR subgroup median VCX INDEX was 0.08 (Q1 0.05, Q3 0.14), in the functional proportionate MR subgroup median VCX INDEX was 0.07 (Q1 0.03, Q3 0.13) and in the functional disproportionate MR subgroup median VCX INDEX was 0.11 (Q1 0.06, Q3 0.19). 20 patients were deemed inoperable by the Heart Team and no further intervention was performed, while 65 patients underwent percutaneous edge-to-edge MV repair with MitraClip device and VCX INDEX was recalculated after the procedure. Median post-MitraClip VCX INDEX was 0.04 (Q1 0.02, Q3 0.07) and a subanalysis based on the echocardiographic MR aetiology was repeated: median post-MitraClip VCX INDEX was 0.02 in the organic MR subgroup (Q1 0.01, Q3 0.05), 0.03 in the functional proportionate MR subgroup (Q1 0.02, Q3 0.07) and 0.05 in the functional disproportionate MR subgroup (Q1 0.03, Q3 0.07). Median VCX INDEX in patients who did not undergo MitraClip implantation was 0.07 (Q1 0.04, Q3 0.12). The variation of VCX INDEX when comparing pre- and post-procedural invasive pressure assessment gives an insight of MitraClip’s favourable haemodynamic effect in terms of VCX INDEX reduction in the treated subgroup of the study and how the intervention has a comparable haemodynamic impact between different echocardiographic MR aetiologies. Further studies are needed to explore the incremental diagnostic role in the decision-making process as well as the prognostic value of the VCX INDEX in patients undergoing percutaneous edge-to-edge MV repair.

Lower limb immobility and venous thromboembolism risk: Investigating preventive measures

<p>Prolonged work-related seated immobility and lower limb immobilisation (LLI) are two situations in which the risk of venous thromboembolism (VTE) is poorly understood, and no evidence-based guidelines for the reduction of risk exist. The aim of this research was to investigate the role of prolonged work-related immobility and LLI as risk factors for VTE and to assess the haemodynamic effects and feasibility of two possible preventive measures; the Legflow device during prolonged work-related immobility and an intermittent pneumatic compression device (IPC) during LLI. Four studies of work-related immobility were conducted: a case-control study to assess the risk of prolonged seated immobility and VTE; a meta-analysis of two case-control studies to assess the risk of VTE in sedentary workers; a study of popliteal vein haemodynamics in ten adults using the Legflow device while seated and a feasibility study of the Legflow device in 96 sedentary office workers in their working environment. Four studies of LLI were completed: a meta-analysis of two case-control studies to assess the association between LLI and VTE risk; an audit of VTE rates in patients with Achilles tendon injury undergoing LLI prescribed prophylactic aspirin; a study of the effect of an IPC device beneath a fibreglass cast on popliteal vein haemodynamics in 24 adults and a feasibility study of the IPC device in patients undergoing LLI at the Fracture Clinic at Wellington Regional Hospital. There was no association between prolonged seated immobility and VTE (odds ratio (OR) 1.18, 95%CI 0.56 to 2.48, P=0.67). Each additional hour seated in a 24 hour period was associated with VTE (OR 1.08, 95%CI 1.01 to 1.6, P=0.02). There was an association between sedentary occupations and VTE (OR 1.79, 95%CI 1.22 to 2.63, P=0.003). The Legflow device increased popliteal vein peak systolic velocity (PVPSV) (difference between the Legflow-mobilised and immobile limb adjusted for baseline 60.0 cm/s, (95%CI 44.6 to 75.3 P<0.001). In the working environment 50% (95%CI 40 to 60%) of sedentary office workers were adherent (use ≥ four times per day) with the Legflow device. LLI was associated with VTE (OR 73.1, 95%CI 10.1 to 530, P<0.001). A total of 14/218 (6.4%, 95%CI 3.6% to 10.5%) Achilles tendon patients prescribed aspirin developed VTE, an incidence similar to the 6.3% identified in a previous patient group not routinely prescribed VTE prophylaxis. The haemodynamic effect of the IPC device was not impaired by its placement within a fibreglass leg cast (difference in PVPSV between IPC in-cast and IPC outside-cast -0.8 cm/s, 95%CI -6.5 to 4.9, P=0.78). Only 7/142 (5%, 95%CI 2.0 to 9.9%) of potentially eligible patients utilised the IPC device in the feasibility study. Prolonged work- and computer-related seated immobility and sedentary professions are associated with VTE. The Legflow increases venous blood flow in seated adults and is a feasible device for use in the office environment. The introduction of aspirin for VTE prophylaxis of VTE during LLI did not influence VTE rates. The haemodynamic effect of the IPC is not impaired in a fibreglass cast, but its use is not a feasible option in the clinical setting of LLI.</p>

Lower limb immobility and venous thromboembolism risk: Investigating preventive measures

<p>Prolonged work-related seated immobility and lower limb immobilisation (LLI) are two situations in which the risk of venous thromboembolism (VTE) is poorly understood, and no evidence-based guidelines for the reduction of risk exist. The aim of this research was to investigate the role of prolonged work-related immobility and LLI as risk factors for VTE and to assess the haemodynamic effects and feasibility of two possible preventive measures; the Legflow device during prolonged work-related immobility and an intermittent pneumatic compression device (IPC) during LLI. Four studies of work-related immobility were conducted: a case-control study to assess the risk of prolonged seated immobility and VTE; a meta-analysis of two case-control studies to assess the risk of VTE in sedentary workers; a study of popliteal vein haemodynamics in ten adults using the Legflow device while seated and a feasibility study of the Legflow device in 96 sedentary office workers in their working environment. Four studies of LLI were completed: a meta-analysis of two case-control studies to assess the association between LLI and VTE risk; an audit of VTE rates in patients with Achilles tendon injury undergoing LLI prescribed prophylactic aspirin; a study of the effect of an IPC device beneath a fibreglass cast on popliteal vein haemodynamics in 24 adults and a feasibility study of the IPC device in patients undergoing LLI at the Fracture Clinic at Wellington Regional Hospital. There was no association between prolonged seated immobility and VTE (odds ratio (OR) 1.18, 95%CI 0.56 to 2.48, P=0.67). Each additional hour seated in a 24 hour period was associated with VTE (OR 1.08, 95%CI 1.01 to 1.6, P=0.02). There was an association between sedentary occupations and VTE (OR 1.79, 95%CI 1.22 to 2.63, P=0.003). The Legflow device increased popliteal vein peak systolic velocity (PVPSV) (difference between the Legflow-mobilised and immobile limb adjusted for baseline 60.0 cm/s, (95%CI 44.6 to 75.3 P<0.001). In the working environment 50% (95%CI 40 to 60%) of sedentary office workers were adherent (use ≥ four times per day) with the Legflow device. LLI was associated with VTE (OR 73.1, 95%CI 10.1 to 530, P<0.001). A total of 14/218 (6.4%, 95%CI 3.6% to 10.5%) Achilles tendon patients prescribed aspirin developed VTE, an incidence similar to the 6.3% identified in a previous patient group not routinely prescribed VTE prophylaxis. The haemodynamic effect of the IPC device was not impaired by its placement within a fibreglass leg cast (difference in PVPSV between IPC in-cast and IPC outside-cast -0.8 cm/s, 95%CI -6.5 to 4.9, P=0.78). Only 7/142 (5%, 95%CI 2.0 to 9.9%) of potentially eligible patients utilised the IPC device in the feasibility study. Prolonged work- and computer-related seated immobility and sedentary professions are associated with VTE. The Legflow increases venous blood flow in seated adults and is a feasible device for use in the office environment. The introduction of aspirin for VTE prophylaxis of VTE during LLI did not influence VTE rates. The haemodynamic effect of the IPC is not impaired in a fibreglass cast, but its use is not a feasible option in the clinical setting of LLI.</p>

Norepinephrine potentiates the efficacy of volume expansion on mean systemic pressure in septic shock

Background Through venous contraction, norepinephrine (NE) increases stressed blood volume and mean systemic pressure (Pms) and exerts a “fluid-like” effect. When both fluid and NE are administered, Pms may not only result from the sum of the effects of both drugs. Indeed, norepinephrine may enhance the effects of volume expansion: because fluid dilutes into a more constricted, smaller, venous network, fluid may increase Pms to a larger extent at a higher than at a lower dose of NE. We tested this hypothesis, by mimicking the effects of fluid by passive leg raising (PLR). Methods In 30 septic shock patients, norepinephrine was decreased to reach a predefined target of mean arterial pressure (65–70 mmHg by default, 80–85 mmHg in previously hypertensive patients). We measured the PLR-induced increase in Pms (heart–lung interactions method) under high and low doses of norepinephrine. Preload responsiveness was defined by a PLR-induced increase in cardiac index ≥ 10%. Results Norepinephrine was decreased from 0.32 [0.18–0.62] to 0.26 [0.13–0.50] µg/kg/min (p < 0.0001). This significantly decreased the mean arterial pressure by 10 [7–20]% and Pms by 9 [4–19]%. The increase in Pms (∆Pms) induced by PLR was 13 [9–19]% at the higher dose of norepinephrine and 11 [6–16]% at the lower dose (p < 0.0001). Pms reached during PLR at the high dose of NE was higher than expected by the sum of Pms at baseline at low dose, ∆Pms induced by changing the norepinephrine dose and ∆Pms induced by PLR at low dose of NE (35.6 [11.2] mmHg vs. 33.6 [10.9] mmHg, respectively, p < 0.01). The number of preload responders was 8 (27%) at the high dose of NE and 15 (50%) at the low dose. Conclusions Norepinephrine enhances the Pms increase induced by PLR. These results suggest that a bolus of fluid of the same volume has a greater haemodynamic effect at a high dose than at a low dose of norepinephrine during septic shock.

The role of mechanical support devices during percutaneous coronary intervention

The practice of interventional cardiology has changed dramatically over the last four decades since Andreas Gruentzig carried out the first balloon angioplasty. The obvious technological improvements in stent design and interventional techniques have facilitated the routine treatment of a higher risk cohort of patients, including those with complex coronary artery disease and poor left ventricular function, and more often in the setting of cardiogenic shock (CS) complicating acute myocardial infarction (AMI). The use of mechanical cardiac support (MCS) in these settings has been the subject of intense interest, particularly over the past decade . A number of commercially available devices now add to the interventional cardiologist’s armamentarium when faced with the critically unwell or high-risk patient in the cardiac catheter laboratory. The theoretical advantage of such devices in these settings is clear- an increase in cardiac output and hence mean arterial pressure, with variable effects on coronary blood flow. In doing so, they have the potential to prevent the downward cascade of ischaemia and hypoperfusion, but there is a paucity of evidence to support their routine use in any patient subset, even those presenting with cardiogenic shock. This review will discuss the use and haemodynamic effect of MCS devices during percutaneous coronary intervention (PCI), and also examine the clinical evidence for their use in patients with cardiogenic shock, and those undergoing ‘high risk’ PCI

Management of neoplastic pericarditis – overview of 156 patients

Introduction Neoplastic pericarditis may develop in any type of cancer, but it is found more frequently in lung cancer, breast cancer and lymphoma. Methods We studied 156 consecutive oncological patients presented with pericardial fluid between 2010 and 2015. Among them, 80 patients were stable, with no indication for pericardial drainage or biopsy, and 76 patients needed surgery to evacuate the pericardium and obtain biopsy. Results Echocardiography and computed tomography were essential in evaluating the topography of the pericardial fluid and the haemodynamic effect, and these investigations helped us choose the appropriate surgical procedure. We performed pericardiocentesis, subxiphoid pericardial drainage, left paraxifoidian pericardial drainage, pericardio-pleural window through intercostal video-assisted thoracic surgery (VATS) or through classical thoracic surgery. Twenty-three patients (14.7%) were admitted and treated for cardiac tamponade. The rate of recurrence after pericardial drainage was 3.89%. The immediate survival at 48 h was 97.3%. Conclusion Long-term survival in patients with malignancy and drained pericardial effusion is influenced mainly by the type of underlying malignant disease. We observed a better survival in patients without cardiac tamponade. Immediate survival depends on the pericardial shock complication – postoperative low cardiac output syndrome (LCOS) or pericardial decompression syndrome (PDS). The indication for pericardial drainage depends on the quantity of pericardial fluid, presence of tamponade, associated pleural effusion and need for biopsy, offering the maximum possible benefit and safety for the patient.

Characterisation and practical importance of exerciseinduced cardiovascular response in a 6 - to 18-year-old population

- Haemodynamic effect also has individual (fitness and health specifics) and population-level (public health impact) relevance to exercise. - Confirmed evidence about the pupils: differences exist between recovery HR and recovery BP trends: recovery HR remained at a high level, in contrast, the recovery BP decreased to starting level or below. - Established a pilot, exercise-related screening test, called “Fit-test”. It provides an opportunity to gain new insight into the relationship between later manifestations of illness and juvenile burden response.  Fit-test is a low-budget, whole-population screening test, which easily fits into an existing school and school health system.  We have found that is also suitable for screening for MHT, preHT, and sustained HT students, and for monitoring the effects of treatment. - We established a database, the first large dataset of haemodynamic changes of normal-weight pupils during a field exercise test.  We defined the population-specific dynamics and experienced individual dissimilarities.  It provided an opportunity to evaluate the physical and cardiovascular fitness together.  Established a possibility for subsequent monitoring of the health status of the affected generation, and risk group. This dataset is useful for physical education teachers, coaches, physicians and exercise physiologists to evaluate actual cardiovascular fitness and haemodynamic responses to exercise in children or adolescents and follow its change.