Revascularization of the lower extremity improves hemodynamics, walking performance, quality of life and calf-muscle pathology in claudicating patients with peripheral arterial disease (PAD), researchers in Nebraska found.
Furthermore, baseline systolic pressure in the foot, at 15 seconds after relief of arterial occlusion (SPP15sec) predicts which claudicating patients will improve by more than 20m of six-minute walking distance (SMWD) according to Shuai Li, MD, a postdoctoral researcher in the group of Iraklis I. Pipinos, MD, and George Casale, PhD, at the University of Nebraska Medical Center. Li and colleagues presented the findings of a study looking at prediction of walking performance after revascularization of the lower extremity for PAD patients suffering from claudication.
“Baseline SPP15sec represents both the severity of macrovascular blockages and the function of resistance arteries,” he explained during a presentation of the data at the annual meeting of the Midwestern Vascular Surgical Society (MVSS), held virtually Sept. 9–12, 2020. “SPP15sec is lower in patients with severe macrovascular blockage and well-preserved resistance arteries—better vasodilation.”
Further explaining the research team’s theory about the prediction value of baseline SPP15sec, Li said that when revascularization relieves macrovascular blockage, patients with lower baseline SPP15sec show more improvement in their clinical function. “Our data suggest that patients who, at the time of initial presentation have well-preserved muscle with relatively healthy resistance arteries, respond best to revascularization operations,” he added.
The researchers set out to evaluate concurrent limb hemodynamics, calf muscle metrics and clinical function in the same cohort of 41 claudicating patients. They measured resting ankle-brachial index (ABI) and stress ABI. SMWD was measured in the corridor, while claudication onset time and peak walking time were captured on a graded treadmill.
In terms of SPP15sec, a cuff above the knee was used to occlude arterial flow for five minutes and systolic pedal pressure was then measured 15 seconds after release of the occlusion.
The results demonstrated an ABI of 0.45 pre-revascularization vs. 0.81 afterwards (p<0.0005). The SPP15sec, meanwhile was 37mmHg before vs. 94mmHg post-revascularization (p<0.0005).
Revascularization improved claudicating patient walking performance and quality of life scores, with an SMWD of 290m vs. 357m pre- and post-revascularization (p<0.005) respectively, Li continued.
But is revascularization a perfect therapy for every claudicating PAD patient who meets treatment criteria? “Not every patient markedly improved in walking performance,” said Li. “Maybe a different treatment or certain therapy in addition to revascularization should be chosen for this small group of PAD patients who had not markedly improved—if we can predict who they are ahead of time.”
With walking performance change ranging from minimal or no change to marked improvement, Li posed the question of whether there were any baseline parameters to predict which patients will markedly improve after revascularization.
“Baseline ABI correlates with revascularization-induced change of SMWD, but not claudication onset time or peak walking time,” he said. “Baseline systolic pedal pressure at 15 seconds post-occlusive reactive hyperemia [SPP15sec] has the strongest correlation.”
Revascularization generally improves both calf myopathy and clinical function of PAD patients, Li concluded, adding: “Baseline SPP15sec predicts which claudicating patient will improve more than 20m in SMWD at six months post-revascularization.”