Quantitative CMR markers of impaired vascular reactivity associated with age and peripheral artery disease

Background: the aim of this study was to develop and evaluate an integrated cmr method incorporating dynamic oximetry,blood flow and pulse-wave velocimetry to assess vascular reactivity in patients with peripheral artery disease (pad) and healthy controls. methods and results. the study population consisted of young healthy subjects (yh,30 ± 7 yrs,n = 19),pad (71 ± 9 yrs,n = 38),and older healthy controls (ohc,68 ± 9 yrs,n = 43). peripheral vascular reactivity was evaluated with two methods,time-resolved quantification of blood flow velocity and oxygenation level in the femoral artery and vein,respectively,performed simultaneously both at rest and hyperemia. aortic stiffness was assessed via pulse-wave velocity. oximetric data showed that compared to ohc,the time-course of the hemoglobin oxygen saturation in pad patients had longer washout time (28.6 ± 1.2 vs 16.9 ± 1.1 s,p < 0.0001),reduced upslope (0.60 ± 0.1 vs 1.3 ± 0.08 hbo§ssub§2§esub§/sec,p < 0.0001) and lower overshoot (8 ± 1.4 vs 14 ± 1.2 hbo§ssub§2§ esub§,p = 0.0064). pad patients also had longer-lasting antegrade femoral artery flow during hyperemia (51 ± 2.1 vs 24 ± 1.8 s,p < 0.0001),and reduced peak-to-baseline flow rate (3.1 ± 0.5 vs 7.4 ± 0.4,p < 0.0001). further,the pulsatility at rest was reduced (0.75 ± 0.32 vs 5.2 ± 0.3,p < 0.0001),and aortic pwv was elevated (10.2 ± 0.4 vs 8.1 ± 0.4 m/s,p = 0.0048). conclusion: the proposed cmr protocol quantifies multiple aspects of vascular reactivity and represents an initial step toward development of a potential tool for evaluating interventions,extrapolating clinical outcomes and predicting functional endpoints based on quantitative parameters. © 2013 langham et al; licensee biomed central ltd.