Pulse wave velocity involving proximal portions of the aorta correlates with the degree of aortic dilatation at the sinuses of valsalva in ascending thoracic aortic aneurysms

Listening to heart sounds through the pressure waveform

Non-invasive diagnostic modalities are integral to cardiovascular care; however, current systems primarily measure peripheral pressure, limiting the breadth of cardiovascular prognostication. We report a novel approach for extracting left side heart sounds using a brachial cuff device. The technique leverages brachial cuff device enhanced signal resolution to capture pressure fluctuations generated by cardiohemic system vibrations, the sound pressure waveform. We analyze left heart catheterization data alongside simultaneous brachial cuff device measurements to correlate sound pressure waveform features with left ventricle (LV) contractility. The extracted sound pressure waveform reveals two prominent oscillatory wave packets, termed WP1 and WP2, originating from cardiac structure vibrations associated with LV contractions and relaxation. We demonstrate that WP1 originates from LV contraction during systolic blood ejection through the aortic valve (AV) and is correlated with LV isovolumetric contraction, clinically measured by LV dPdt-max (Pearson-R = 0.65, p < 0.001). Additionally, we show that WP2 comes from LV elongation required for blood flow deceleration at the end of systole, causing AV closure, and is correlated with LV isovolumetric relaxation, measured by LV ndPdt-max (Pearson-R = 0.55, p < 0.001). These findings highlight the value of cuff sound pressure waveforms in providing insights about dynamic coupling of the LV-Aorta complex for non-invasive assessment of LV contractility.

Blood-wall fluttering instability as a physiomarker of the progression of thoracic aortic aneurysms

The diagnosis of aneurysms is informed by empirically tracking their size and growth rate. Here, by analysing the growth of aortic aneurysms from first principles via linear stability analysis of flow through an elastic blood vessel, we show that abnormal aortic dilatation is associated with a transition from stable flow to unstable aortic fluttering. This transition to instability can be described by the critical threshold for a dimensionless number that depends on blood pressure, the size of the aorta, and the shear stress and stiffness of the aortic wall. By analysing data from four-dimensional flow magnetic resonance imaging for 117 patients who had undergone cardiothoracic imaging and for 100 healthy volunteers, we show that the dimensionless number is a physiomarker for the growth of thoracic ascending aortic aneurysms and that it can be used to accurately discriminate abnormal versus natural growth. Further characterization of the transition to blood-wall fluttering instability may aid the understanding of the mechanisms underlying aneurysm progression in patients.

Aortic Wall Inflammation in the Pathogenesis, Diagnosis and Treatment of Aortic Aneurysms

The role of inflammation in the development of aortic aneurysms is emerging, along with the potential diagnostic and therapeutical potential of this correlation. Abdominal aorta aneurysms have a strong inflammatory substrate since atherosclerosis, which is undoubtedly linked to inflammation, is also a predisposing factor to their formation. Yet, data have emerged that the development of thoracic aorta aneurysms involves several inflammatory pathways, although they were previously referred to as a non-inflammatory disease. Since aortic aneurysms are mainly asymptomatic during their clinical course until their complications-which may be lethal-serum biomarkers for their early diagnosis are a necessity. Studies highlight that inflammation molecules may have a critical role in that direction. In addition, imaging techniques that trace aortic wall inflammation are developed in order to predict aneurysm growth rates and sites vulnerable of rupture. Several anti-inflammatory agents have been also studied in animal models and clinical trials for the treatment of aortic aneurysms. This review highlights the role of inflammation in pathogenesis, diagnosis and treatment of aortic aneurysms.

Aortic Root Dimensions and Pulse Wave Velocity in Young Competitive Athletes

The assessment of aortic root dimensions is a cornerstone in cardiac pre-participation screening as dilation can result in severe cardiac events. Moreover, it can be a hint for an underlying connective tissue disease, which needs individualized sports counseling. This study examines the prevalence of aortic root dilatation in a cohort and its relationship to arterial stiffness as an early marker of cardiovascular risk due to vascular aging. From May 2012 to March 2018, we examined 281 young male athletes (14.7 ± 2.1 years) for their aortic root dimension. Moreover, we noninvasively assessed arterial stiffness parameter during pre-participation screening. Mean aortic diameter was 25.9 ± 3.1 mm and 18 of the 281 (6.4%) athletes had aortic root dilation without other clinical evidence of connective tissue disease. After adjusting for BSA, there was no association of aortic root diameter to pulse wave velocity (p = −0.054 r = 0.368) nor to central blood pressure (p = −0.029 r = 0.634). Thus, although a significant proportion of young athletes had aortic root dilatation, which certainly needs regular follow up, no correlation with arterial stiffness was found. It could be suggested that a dilated aortic root in young athletes does not alter pulse waveform and pulse reflection, and thus there is no increased cardiovascular risk in those subjects.

Autograft remodeling after the Ross procedure by cardiovascular magnetic resonance imaging: Aortic stenosis versus insufficiency

BACKGROUND

Studies suggest that patients undergoing the Ross procedure for aortic insufficiency are at greater risk of autograft dilatation than those with aortic stenosis. By using a tailored Ross technique to mitigate autograft dilatation in patients with aortic insufficiency, we aimed to compare the biomechanical and morphologic remodeling of the autograft at 1 year between patients with aortic insufficiency and patients with aortic stenosis.

METHODS

A total of 210 patients underwent a Ross procedure (2011-2016). Of those, 86 patients (mean age 43 ± 13 years; 32% were female) completed preoperative and postoperative cardiovascular magnetic resonance imaging. A total of 71 studies were suitable for analysis: 41 patients with aortic stenosis and 30 patients with aortic insufficiency. Nine healthy adults were used as controls. Autograft root dimensions, individual sinus volumes, and distensibility were measured using cardiovascular magnetic resonance.

RESULTS

At 1 year, there was no difference in autograft root dimensions between patients with aortic stenosis (mean annulus 25.1 ± 3.1 mm and sinus diameters 35 ± 4.1 mm) and patients with aortic insufficiency (26.6 ± 3 mm and 37.1 ± 3.5 mm; P = .12 and .06, respectively). Relative sinus of Valsalva volumes were symmetrical in the aortic stenosis (right 34.8% ± 4%, left 33.7% ± 3.5%, noncoronary 31.4% ± 3.2%) and aortic insufficiency groups (34.8% ± 3.9%, 33.8% ± 2.8%, 31.3% ± 3.7%, P = .85, .92, and .82), and similar to those of healthy adults. Aortic root distensibility was reduced in both groups compared with healthy adults (P = .003), but was similar between aortic stenosis (3.12 ± 1.58 × 10^-3 mm Hg^-1) and aortic insufficiency (3.04 ± 1.15 × 10^-3 mm Hg^-1; P = .9).

CONCLUSIONS

Using a tailored technique, there were no differences in the morphologic or biomechanical remodeling of the autograft root 1 year after the Ross procedure between patients with aortic stenosis and patients with aortic insufficiency. However, autograft roots are stiffer than native aortic roots.

Accentuating and Opposing Factors Leading to Development of Thoracic Aortic Aneurysms Not Due to Genetic or Inherited Conditions

Understanding and unraveling the pathophysiology of thoracic aortic aneurysm (TAA), a vascular disease with a potentially high-mortality rate, is one of the next frontiers in vascular biology. The processes leading to the formation of TAA, of unknown cause, so-called degenerative TAA, are complex. This review advances the concept of promoters and inhibitors of the development of degenerative TAA. Promoters of TAA development include age, blood pressure elevation, increased pulse pressure, neurohumeral factors increasing blood pressure, inflammation specifically IFN-γ, IL-1 β, IL-6, TNF-α, and S100 A12; the coagulation system specifically plasmin, platelets, and thrombin as well as matrix metalloproteinases (MMPs). SMAD-2 signaling and specific microRNAs modulate TAA development. The major inhibitors or factors opposing TAA development are the constituents of the aortic wall (elastic lamellae, collagen, fibulins, fibronectin, proteoglycans, and vascular smooth muscle cells), which maintain normal aortic dimensions in the face of aortic wall stress, specific tissue MMP inhibitors, plasminogen activator inhibitor-1, protease nexin-1, and Syndecans. Increases in promoters and reductions in inhibitors expand the thoracic aorta leading to TAA formation.