Arterial adaptations to training among first time marathoners

Effect of Exercise on Carotid Artery Intima-Media Thickness in Adults: A Systematic Review and Meta-Analysis

BACKGROUND

Carotid intima-media thickness (cIMT) is a validated surrogate marker of atherosclerosis that is independently associated with the risk for cardiovascular disease. Recent studies on the effect of exercise on cIMT have yielded conflicting results.

METHODS

Studies that were available up until October 30, 2021 from the PubMed, Cochrane Library, Embase, and Web of Science databases were included in the analysis. Subgroup analyses were performed to determine the effects of the type, intensity, and duration of exercise on cIMT.

RESULTS

This review included 26 studies with 1370 participants. Compared with control participants, those who engaged in exercise showed a decline in cIMT (weighted mean difference [WMD] -0.02; 95% confidence interval [CI], -0.03 to -0.01; I2 = 90.1%). Participants who engaged in aerobic (WMD -0.02; 95% CI, -0.04 to -0.01; I2 = 52.7%) or resistance (WMD -0.01; 95% CI, -0.02 to -0.00; I2 = 38.5%) exercise showed lower cIMT compared with control participants. An exercise duration of >6 months was associated with a 0.02 mm reduction in cIMT. In participants with low cIMT at baseline (<0.7 mm), exercise alone was not associated with a change in cIMT (WMD -0.01; 95% CI, -0.03 to 0.00; I2 = 93.9%).

CONCLUSIONS

Exercise was associated with reduced cIMT in adults. Aerobic exercise is associated with a greater decline in cIMT than other forms of exercise. Large, multicenter, randomized controlled trials are required to establish optimal exercise protocols for improving the pathological process of atherosclerosis.

A predictive multiscale model of in-stent restenosis in femoral arteries: linking haemodynamics and gene expression with an agent-based model of cellular dynamics

In-stent restenosis (ISR) is a maladaptive inflammatory-driven response of femoral arteries to percutaneous transluminal angioplasty and stent deployment, leading to lumen re-narrowing as consequence of excessive cellular proliferative and synthetic activities. A thorough understanding of the underlying mechanobiological factors contributing to ISR is still lacking. Computational multiscale models integrating both continuous- and agent-based approaches have been identified as promising tools to capture key aspects of the complex network of events encompassing molecular, cellular and tissue response to the intervention. In this regard, this work presents a multiscale framework integrating the effects of local haemodynamics and monocyte gene expression data on cellular dynamics to simulate ISR mechanobiological processes in a patient-specific model of stented superficial femoral artery. The framework is based on the coupling of computational fluid dynamics simulations (haemodynamics module) with an agent-based model (ABM) of cellular activities (tissue remodelling module). Sensitivity analysis and surrogate modelling combined with genetic algorithm optimization were adopted to explore the model behaviour and calibrate the ABM parameters. The proposed framework successfully described the patient lumen area reduction from baseline to one-month follow-up, demonstrating the potential capabilities of this approach in predicting the short-term arterial response to the endovascular procedure.

3D modelling of drug-coated balloons for the treatment of calcified superficial femoral arteries

Background/Objectives

Drug-coated balloon therapy for diseased superficial femoral arteries remains controversial. Despite its clinical relevance, only a few computational studies based on simplistic two-dimensional models have been proposed to investigate this endovascular therapy to date. This work addresses the aforementioned limitation by analyzing the drug transport and kinetics occurring during drug-coated balloon deployment in a three-dimensional geometry.

Methods

An idealized three-dimensional model of a superficial femoral artery presenting with a calcific plaque and treated with a drug-coated balloon was created to perform transient mass transport simulations. To account for the transport of drug (i.e. paclitaxel) released by the device, a diffusion-reaction equation was implemented by describing the drug bound to specific intracellular receptors through a non-linear, reversible reaction. The following features concerning procedural aspects, pathologies and modelling assumptions were investigated: (i) balloon application time (60–180 seconds); (ii) vessel wall composition (healthy vs. calcified wall); (iii) sequential balloon application; and (iv) drug wash-out by the blood stream vs. coating retention, modeled as exponential decay.

Results

The balloon inflation time impacted both the free and specifically-bound drug concentrations in the vessel wall. The vessel wall composition highly affected the drug concentrations. In particular, the specifically-bound drug concentration was four orders of magnitude lower in the calcific compared with healthy vessel wall portions, primarily as a result of reduced drug diffusion. The sequential application of two drug-coated balloons led to modest differences (~15%) in drug concentration immediately after inflation, which became negligible within 10 minutes. The retention of the balloon coating increased the drug concentration in the vessel wall fourfold.

Conclusions

The overall findings suggest that paclitaxel kinetics may be affected not only by the geometrical and compositional features of the vessel treated with the drug-coated balloon, but also by balloon design characteristics and procedural aspects that should be carefully considered.

Vascular adaptations in nonstimulated areas during hybrid cycling or handcycling in people with a spinal cord injury: a pilot study of 10 cases

STUDY DESIGN

Sub-study of a randomized controlled trial.

OBJECTIVES

To examine if hybrid cycling (cycling with the legs via electrical stimulation combined with voluntary handcycling) compared to handcycling leads to different systemic vascular adaptations in individuals with a long-term spinal cord injury (SCI).

SETTING

Two rehabilitation centers in the Netherlands.

METHODS

Ten individuals with a SCI trained on a hybrid bicycle (N = 5) or a handcycle (N = 5) for 16 weeks twice a week. Prior to and following the training the intima media thickness (IMT) of the common coronary artery (CCA) and superficial femoral artery (SFA) were measured and the flow-mediated dilation (FMD) of the brachial artery (BA) was analyzed.

RESULTS

Before training, there were no significant differences in any of the outcome measures between the groups. We found no change in CCA IMT (pre: 0.616 mm, post: 0.586 mm), or in SFA (pre: 0.512 mm, post: 0.520 mm) after hybrid cycling. We also found no change in FMD % of BA after hybrid cycling (pre: 9.040%, post: 9.220%). There were no changes in CCA IMT, SFA IMT, and FMD% after handcycling either.

CONCLUSIONS

It appears that 16 weeks of twice-weekly training of up to 30 min on a hybrid bicycle or handcycle does not lead to systemic vascular adaptations. A larger sample size and training protocol with more frequent and higher intensity training (which might involve a home-based setting and an adapted period prior to the training) might show different results.

Training for a First-Time Marathon Reverses Age-Related Aortic Stiffening

BACKGROUND

Aging increases aortic stiffness, contributing to cardiovascular risk even in healthy individuals. Aortic stiffness is reduced through supervised training programs, but these are not easily generalizable.

OBJECTIVES

The purpose of this study was to determine whether real-world exercise training for a first-time marathon can reverse age-related aortic stiffening.

METHODS

Untrained healthy individuals underwent 6 months of training for the London Marathon. Assessment pre-training and 2 weeks post-marathon included central (aortic) blood pressure and aortic stiffness using cardiovascular magnetic resonance distensibility. Biological "aortic age" was calculated from the baseline chronological age-stiffness relationship. Change in stiffness was assessed at the ascending (Ao-A) and descending aorta at the pulmonary artery bifurcation (Ao-P) and diaphragm (Ao-D). Data are mean changes (95% confidence intervals [CIs]).

RESULTS

A total of 138 first-time marathon completers (age 21 to 69 years, 49% male) were assessed, with an estimated training schedule of 6 to 13 miles/week. At baseline, a decade of chronological aging correlated with a decrease in Ao-A, Ao-P, and Ao-D distensibility by 2.3, 1.9, and 3.1 × 10^-3 mm Hg^-1, respectively (p < 0.05 for all). Training decreased systolic and diastolic central (aortic) blood pressure by 4 mm Hg (95% CI: 2.8 to 5.5 mm Hg) and 3 mm Hg (95% CI: 1.6 to 3.5 mm Hg). Descending aortic distensibility increased (Ao-P: 9%; p = 0.009; Ao-D: 16%; p = 0.002), while remaining unchanged in the Ao-A. These translated to a reduction in "aortic age" by 3.9 years (95% CI: 1.1 to 7.6 years) and 4.0 years (95% CI: 1.7 to 8.0 years) (Ao-P and Ao-D, respectively). Benefit was greater in older, male participants with slower running times (p < 0.05 for all).

CONCLUSIONS

Training for and completing a marathon even at relatively low exercise intensity reduces central blood pressure and aortic stiffness-equivalent to a ∼4-year reduction in vascular age. Greater rejuvenation was observed in older, slower individuals.