Associations between left ventricular function, vascular function and measures of cerebral small vessel disease: a cross-sectional magnetic resonance imaging study of the UK Biobank.

OBJECTIVES: Impaired cardiovascular function has been associated with cognitive deterioration; however, to what extent cardiovascular dysfunction plays a role in structural cerebral changes remains unclear. We studied whether vascular and left ventricular (LV) functions are associated with measures of cerebral small vessel disease (cSVD) in the middle-aged general population. METHODS: In this cross-sectional analysis of the UK Biobank, 4366 participants (54% female, mean age 61 years) underwent magnetic resonance imaging to assess LV function (ejection fraction [EF] and cardiac index [CI]) and cSVD measures (total brain volume, grey and white matter volumes, hippocampal volume and white matter hyperintensities [WMH]). Augmentation index (AIx) was used as a measure of arterial stiffness. Linear and non-linear associations were evaluated using cardiovascular function measures as determinants and cSVD measures as outcomes. RESULTS: EF was non-linearly associated with total brain volume and grey matter volume, with the largest brain volume for an EF between 55 and 60% (both p < 0.001). EF showed a negative linear association with WMH (- 0.23% [- 0.44; - 0.02], p = 0.03), yet no associations were found with white matter or hippocampal volume. CI showed a positive linear association with white matter (ß 3194 mm3 [760; 5627], p = 0.01) and hippocampal volume (ß 72.5 mm3 [23.0; 122.0], p = 0.004). No associations were found for CI with total brain volume, grey matter volume or WMH. No significant associations were found between AIx and cSVD measures. CONCLUSIONS: This study provides novel insights into the complex associations between the heart and the brain, which could potentially guide early interventions aimed at improving cardiovascular function and the prevention of cSVD. KEY POINTS: • Ejection fraction is non-linearly and cardiac index is linearly associated with MRI-derived measures of cerebral small vessel disease. • No associations were found for arterial stiffness with cSVD measures.

4D flow MRI of type B dissection with later retrograde progression to type A dissection in Marfan: a case report.

BACKGROUND: Due to the malfunction of connective tissue, Marfan patients are at increased risk of aortic dissection. Uncomplicated acute type B dissection is usually managed with medical therapy. Retrograde progression or new type A dissection is a relatively rare but often fatal complication that occur most frequently in the first 6 months after acute type B dissection. CASE SUMMARY: We present a 31-year-old male with Marfan syndrome and a recent uncomplicated type B dissection from the left subclavian to the right common iliac artery who underwent 4D flow magnetic resonance imaging (MRI). The dissection had a large proximal intimal tear just distal to the left subclavian artery (15 mm) and large false lumen (35 mm). Aortic blood flow just distal to the left subclavian artery (3.6 L/min) was split disproportionately into the true (0.8 L/min, 22%) and false lumen (2.8 L/min, 78%). 4D flow streamlines revealed vortical flow in the proximal false lumen. Increased wall shear stress was observed at the sinotubular junction (STJ), inner wall of the ascending aorta and around the subclavian artery. Two weeks after MRI, the patient presented with jaw pain. Computed tomography showed a type A dissection with an entry tear at the STJ for which an acute valve-sparing root, ascending and arch replacement was performed. DISCUSSION: Better risk assessment of life-threatening complications in uncomplicated type B dissections could improve treatment strategies in these patients. Our case demonstrates that besides clinical and morphological parameters, flow derived parameters could aid in improved risk assessment for retrograde progression from uncomplicated type B dissection to acute type A dissection.

The impact of visceral and general obesity on vascular and left ventricular function and geometry: a cross-sectional magnetic resonance imaging study of the UK Biobank.

AIMS: We aimed to evaluate the associations of body fat distribution with cardiovascular function and geometry in the middle-aged general population. METHODS AND RESULTS: Four thousand five hundred and ninety participants of the UK Biobank (54% female, mean age 61.1 ± 7.2 years) underwent cardiac magnetic resonance for assessment of left ventricular (LV) parameters [end-diastolic volume (EDV), ejection fraction (EF), cardiac output (CO), and index (CI)] and magnetic resonance imaging for body composition analysis [subcutaneous adipose tissue (SAT) and visceral adipose tissue (VAT)]. Body fat percentage (BF%) was assessed by bioelectrical impedance. Linear regressions were performed to assess the impact of visceral (VAT) and general (SAT and BF%) obesity on cardiac function and geometry. Visceral obesity was associated with a smaller EDV [VAT: ß -1.74 (-1.15 to -2.33)], lower EF [VAT: ß -0.24 (-0.12 to -0.35), SAT: ß 0.02 (-0.04 to 0.08), and BF%: ß 0.02 (-0.02 to 0.06)] and the strongest negative association with CI [VAT: ß -0.05 (-0.06 to -0.04), SAT: ß -0.02 (-0.03 to -0.01), and BF% ß -0.01 (-0.013 to -0.007)]. In contrast, general obesity was associated with a larger EDV [SAT: ß 1.01 (0.72-1.30), BF%: ß 0.37 (0.23-0.51)] and a higher CO [SAT: ß 0.06 (0.05-0.07), BF%: ß 0.02 (0.01-0.03)]. In the gender-specific analysis, only men had a significant association between VAT and EF [ß -0.35 (-0.19 to -0.51)]. CONCLUSION: Visceral obesity was associated with a smaller LV EDV and subclinical lower LV systolic function in men, suggesting that visceral obesity might play a more important role compared to general obesity in LV remodelling.