Quantitative CMR markers of impaired vascular reactivity associated with age and peripheral artery disease
- PDF / 828,951 Bytes
- 10 Pages / 595.28 x 793.7 pts Page_size
- 80 Downloads / 165 Views
RESEARCH
Open Access
Quantitative CMR markers of impaired vascular reactivity associated with age and peripheral artery disease Michael C Langham1, Erin K Englund1, Emile R Mohler III2, Cheng Li1, Zachary B Rodgers1, Thomas F Floyd3 and Felix W Wehrli1*
Abstract 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 pulsewave 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 HbO2/sec, p < 0.0001) and lower overshoot (8 ± 1.4 vs 14 ± 1.2 HbO2, 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. Keywords: Peripheral arterial disease, Atherosclerosis, Microvascular function, Pulse-wave velocity, Blood oxygen saturation, Phase image, Magnetic resonance oximetry
Background Peripheral artery disease (PAD) is most commonly due to atherosclerosis. Currently, it is estimated that approximately ten million people in the United States are affected by PAD and the number is expected to grow as the population ages [1]. In spite of its high prevalence the disease often goes unnoticed because the vast majority of PAD patients have no classic claudication symptoms, which typically occur at an advanced stage. The initial test for diagnosing patients with clinical * Correspondence: [email protected] 1 Department of Radiology, University of Pennsylvania Medical Center, 3400 Spruce Street, Philadelphia, PA 19104, USA Full list of author information is available at the end of the article
symptoms is measurement of the ankle-brachial index (ABI). A low ABI is a strong indicator of the presence of PAD but a normal ABI does not rule out risk due to the false negative rates [2], which can be understood based on t
Data Loading...
