Affected Microcirculation and Vascular Hemodynamics in Takayasu Arteritis

Abstract

Introduction: Takayasu arteritis (TAK) is a rare inflammatory disease affecting aorta and its major branches. Ultrasound (US) can detect inflammatory features in the arterial wall, but less is known regarding skin microcirculation and vascular hemodynamics. The aim was to study if assessment of these variables could add valuable information regarding vascular affection in TAK. Methods: 17 patients diagnosed with TAK and 17 age- and sex-matched healthy controls were included. Microcirculatory peak oxygen saturation (OxyP) in the skin after induced ischemia was evaluated with laser Doppler flowmetry/diffuse reflectance spectroscopy. Cerebrovascular reserve capacity (CVR) in the brain was assessed with transcranial Doppler (TCD). Pulse waves were recorded in the radial artery by the aid of applanation tonometry, for calculation of central augmentation index (AIx75). Intima-media thickness (IMT) and stenosis/occlusions were evaluated using US in carotid and central arteries. Results: Reduced OxyP (79 ± 8% vs. 87 ± 4%, p < 0.001) was seen in patients with TAK regardless of significant arterial stenosis/occlusion or not. Increased AIx75 (22.3 ± 13.6 vs. 9.2 ± 16.3, p = 0.01) was seen in TAK patients without significant stenosis/occlusions. No differences were found in CVR, regardless of proximal stenosis. However, signs of a more high-resistance flow profile were seen in arteria cerebri media. Conclusion: Regardless of arterial stenosis or not, impaired microcirculation of the skin and preserved CVR in the brain were found in subjects with TAK. Signs of increased arterial stiffness in the brain and central arteries were observed. The value of these findings for prediction of future cardiovascular events needs to be clarified in further studies.

Keywords: augmentation index; breath hold index; intima-media thickness; microcirculation; peak oxygen saturation; takayasu arteritis; ultrasound.

FIGURE 1

Oxygen saturation (%), baseline, during arterial occlusion (between 5 and 10 min), and in the post-occlusive hyperemia phase, in one healthy control and in one Takayasu patients with subclavian stenosis. Red arrow marks oxygen saturation peak.

FIGURE 2

Aortic pulse wave analysis. Pulse pressure waveform from one of the healthy controls demonstrating reflecting wave during late systole, and from a Takayasu patient without proximal stenosis, where reflecting wave during early systole produces an augmented systolic pressure. The difference between red and blue line is the augmented pressure (the difference between the second and first systolic peak pressure). mmHg, millimeter of mercury; ms, millisecond.

FIGURE 3

Equation of Mean flow velocity and Breath Hold Index. MFV, Mean flow velocity; EDV, End diastolic velocity; PSV, Peak systolic velocity; BHI, Breath hold index; sec, seconds; BH. Breath hold.

FIGURE 4

(A) OxyP (%) in controls and patients with or without significant stenosis or occlusion in the arm arteries. OxyP, peak oxygen saturation. (B) AIx75 (%) in controls and patients without significant stenosis or occlusion in the arm arteries. AIx75, Augmentation Index adjusted for heart rate 75.