Publications by authors named "Lindenberger M"

Aims: Understanding the mechanisms underlying ascending aortic dilation is imperative for refined risk stratification of these patients, particularly among incidentally identified patients, most commonly presenting with tricuspid valves. The aim of this study was to explore associations between ascending aortic haemodynamics, assessed using four-dimensional flow cardiovascular magnetic resonance imaging (4D flow CMR), and circulating biomarkers in aortic dilation.

Methods And Results: Forty-seven cases with aortic dilation (diameter ≥ 40 mm) and 50 sex-and age-matched controls (diameter < 40 mm), all with tricuspid aortic valves, underwent 4D flow CMR and venous blood sampling.

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It has been proposed that formation of abdominal aortic aneurysm (AAA) is part of a systemic arterial dilatative disease. However, arteries in the upper extremities are scarcely studied and it remains unclear whether both muscular and elastic arteries are affected by the proposed systemic arterial dilatation. The aim of this study was to investigate the diameter and stiffness of muscular and elastic arteries in arterial branches originating from the aortic arch.

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Objective: Abdominal aortic aneurysm (AAA) is commonly defined as localised aortic dilatation with a diameter > 30 mm. The pathophysiology of AAA includes chronic inflammation and enzymatic degradation of elastin, possibly increasing aortic wall stiffness and pulse wave velocity (PWV). Whether aortic stiffness is more prominent in the abdominal aorta at the aneurysm site is not elucidated.

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Background: Increased vascular tortuosity is a hallmark of ageing of the vascular system, including the aorta. However, the impact of tortuosity on aortic blood flow is unknown. We hypothesized that increased tortuosity would be associated with increased blood flow helicity and with decreased degree of blood flow turbulence as measured by the turbulent kinetic energy (TKE).

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Objective: Abdominal aortic aneurysm (AAA) is associated with dilatation of central elastic arteries, while it is uncertain whether peripheral muscular arteries are affected. The aim of this study was to investigate radial artery diastolic lumen diameter (LD), wall thickness, and circumferential wall stress (CWS) in patients with AAA.

Methods: We included 130 men with AAA (mean age, 70.

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Background: Abdominal aortic aneurysms (AAA) can lead to catastrophic events such as dissection or rupture, and are an expression of general aortic disease. Low wall shear stress (WSS), high oscillatory shear index (OSI), and high relative residence time (RRT) have been correlated against increased uptake of inflammatory markers in the vessel wall and may improve risk stratification of AAA. We sought to obtain a comprehensive view of WSS, OSI, and RRT in the whole aorta for patients with AAA and age-matched elderly controls and young normal controls.

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Objective: Abdominal aortic aneurysm (AAA) is associated with morphological and functional changes in both aneurysmal and non-aneurysmal arteries. However, it remains uncertain whether similar changes also exist in the venous vasculature. The aim of this study was to evaluate global venous function in patients with AAA and controls.

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Introduction: Vasovagal reflex is the most common type of syncope but its etiology is not fully elucidated. Venous return and cardiac output are key in hemodynamic control. The aim of the study was to assess cardiovascular biomarkers and echocardiographic measures at rest and during hypovolemia in women with and without a history of vasovagal syncope.

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Purpose: To examine methods for visualizing and quantifying flow stasis in abdominal aortic aneurysms (AAA) using 4D Flow MRI.

Methods: Three methods were investigated: conventional volumetric residence time (VRT), mean velocity analysis (MVA), and particle travel distance analysis (TDA). First, ideal 4D Flow MRI data was generated using numerical simulations and used as a platform to explore the effects of noise and background phase-offset errors, both of which are common 4D Flow MRI artifacts.

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Background: There is a growing body of evidence on the relevance of using frailty measures also in a cardiovascular context. The estimated time to death is crucial in clinical decision-making in cardiology. However, data on the importance of frailty in long-term mortality are very scarce.

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Turbulent blood flow is implicated in the pathogenesis of several aortic diseases but the extent and degree of turbulent blood flow in the normal aorta is unknown. We aimed to quantify the extent and degree of turbulece in the normal aorta and to assess whether age impacts the degree of turbulence. 22 young normal males (23.

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Background: Young patients with diabetes present with reduced compensatory responses to hypovolemic stress. Less compliant veins could be a contributing factor, since roughly two-thirds of the blood volume resides in the venous system as a blood reservoir, adjusting proper venous inflow to the heart. The aim of this study was to measure venous compliance and lower limb blood pooling during hypovolemic stress, and to correlate them to indices of diabetes severity and glucose control.

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Although vasovagal syncope (VVS) is a common clinical condition, the underlying pathophysiology is not fully understood. A decrease in cardiac output has recently been suggested as a factor in orthostatic VVS. The aim was to investigate compensatory mechanisms to maintain central blood volume and venous return during hypovolemic stress in women with VVS.

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Background And Aim: Slower lower limb blood pooling and associated blunted sympathetic activation has been detected in healthy women prone to orthostatic syncope. Whether these findings are true also for patients with vasovagal syncope (VVS) is unknown. The aim was to investigate initial blood pooling time (poolingtime, time to 50% of total blood pooling) together with hemodynamic responses and orthostatic tolerance during lower body negative pressure (LBNP) in VVS and healthy controls.

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The influence of lower limb venous compliance on orthostatic vasovagal syncope (VVS) is uncertain. The most widespread technique to calculate venous compliance uses a nonphysiological quadratic regression equation. Our aim was therefore to construct a physiologically derived venous wall model (VWM) for calculation of calf venous compliance and to determine the effect of venous compliance on tolerance to maximal lower body negative pressure (LBNP).

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What is the central question of this study? Orthostatic stress is mostly caused by venous blood pooling in the lower limbs. Venous distension elicits sympathetic responses, and increased distension speed enhances the cardiovascular response. We examine whether lower limb blood pooling rate during lower body negative pressure is linked to orthostatic intolerance.

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Purpose: Calf venous compliance (C calf) is commonly evaluated with venous occlusion plethysmography (VOP) during a standard cuff deflation protocol. However, the technique relies on two not previously validated assumptions concerning thigh cuff pressure (P cuff) transmission and the impact of net fluid filtration (F filt) on C calf. The aim was to validate VOP in the lower limb and to develop a model to correct for F filt during VOP.

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Objective: Diabetes is associated with hemodynamic instability during different situations involving acute circulatory stress in daily life. Young men with type 1 diabetes have been shown to have impaired circulatory response to hypovolemic stress. The effect of type 1 diabetes on cardiovascular response to hypovolemia in young women is unknown, however.

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The present study measured self-perceived thirst and plasma angiotensin II (ATII) concentrations during graded hypovolaemic stress, induced by lower body negative pressure (LBNP), to elucidate the dependence of thirst on haemodynamics. A total of 24 women aged between 20 and 36 (mean age, 23) years rated their thirst on a visual analogue scale, graded from 0 to 100, when LBNP of 20, 30 and 40 mmHg was applied. Half of the women had a history of vasovagal syncope (VVS).

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Background: For the large population of elderly patients with cardiovascular disease, it is crucial to identify clinically relevant measures of biological age and their contribution to risk. Frailty is denoting decreased physiological reserves and increased vulnerability. We analysed the manner in which the variable frailty is associated with 1-year outcomes for elderly non-ST-segment elevation myocardial infarction (NSTEMI) patients.

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Elderly humans are more vulnerable to trauma and hemorrhage than young and elderly men and respond with decreased defense of central blood volume during acute experimental hypovolemia induced by lower body negative pressure (LBNP). However, these defense mechanisms have not been evaluated in elderly women. The aim of this study was to determine the effectiveness of compensatory responses to defend central blood volume during experimental hypovolemia in elderly and young women.

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Background: For the large and growing population of elderly patients with cardiovascular disease, it is important to identify clinically relevant measures of biological age and their contribution to risk. Frailty is an emerging concept in medicine denoting increased vulnerability and decreased physiological reserves. We analyzed the manner in which the variable frailty predicts short-term outcomes for elderly non-ST-segment elevation myocardial infarction patients.

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Objectives: The greater saphenous vein (GSV) is commonly used in autologous vein graft surgery. GSV diameter has proven to influence graft patency, and furthermore venous compliance might be of importance. The purpose of the study was to evaluate the effect of age on GSV diameter and compliance, and to evaluate the effect of nitroglycerine (NTG).

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Diabetes mellitus is associated with decreased haemodynamic stability and reduced tolerance to hypovolaemia. Compensatory haemodynamic responses during experimental hypovolaemia in type 1 diabetes patients with (DMR+) and without (DMR-) retinopathy as well as healthy controls (C) were studied. Lower body negative pressure created hypovolaemic circulatory stress.

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