A Novel Index Using Ankle Hemodynamic Parameters to Assess the Severity of Peripheral Arterial Disease: A Pilot Study

Abstract

In peripheral arterial disease (PAD) of the lower extremities, the presence of flow-limiting stenoses can be objectively detected by the ankle-brachial index (ABI). However, the severity of ischemic symptoms is not necessarily associated with the ABI value. Atherosclerotic plaque in lower extremity PAD induces ankle arterial stiffness and reduces ankle vascular resistance, which may decrease ankle blood flow and cause ischemic symptoms. We hypothesized that the ankle hemodynamic index (AHI), defined as the ratio of ankle arterial stiffness to ankle vascular resistance, could be used to assess the blood supply deficiency in a diseased lower limb in patients with PAD. The 85 consecutive patients with PAD who were retrospectively analyzed in this study had Rutherford grade 1 to grade 6 ischemia diagnosed as PAD and significant stenotic lesions (>50% diameter stenosis) of the lower extremity on contrast angiography. The AHI was calculated as the product of the ankle pulse pressure and the ratio of heart rate to ankle mean arterial pressure (ankle pulse pressure × heart rate/ankle mean arterial pressure). The Rutherford grade was significantly correlated with the AHI (r = 0.50, P < 0.001), but not with the ABI (r = 0.07, P = 0.52). Multiple ordinal regression analysis showed that anemia (odds ratio 0.66, P = 0.002) and AHI (odds ratio 1.04, P = 0.02) were independently associated with Rutherford grade. Our study shows that AHI, a novel parameter based on the ABI measurement, is well correlated with ischemic symptoms, and may be a useful means to assess the arterial blood supply of the lower extremities of patients with PAD.

Impact of the isometric contraction of the calf on the local microcirculation

“…O estilo de vida pode levar a uma diminuição da atividade física, manifestada pela diminuição da produção de força [2] . A fraqueza resultante pode levar a uma diminuição no fluxo sanguíneo dos membros inferiores e a um comprometimento dos mecanismos de regulação vascular [3] . A postura ortostática dinâmica pode influenciar mecanismos fisiológicos vasculares [2] em escala macrodinâmica de acordo com a atividade específica dos grupos musculares.…”

“…Depending on the integrity of the veno-arterial reflex, the action of the respiratory and skeletal muscle pumps are mechanisms facilitate the pressure gradient between central and peripheral venous compartments [1] . Lifestyle may lead to a decreased physical activity, with decreased strength production [2] .The resulting weakness may lead to a decrease in lower limb blood flow and a compromise of vascular regulation mechanisms [3] . The orthostatic dynamic posture can influence vascular physiological mechanisms [2] on a macrodynamic scale according to the specific activity of muscle groups.…”

Estimating the diagnostic accuracy of the ankle–brachial pressure index for detecting peripheral arterial disease in people with diabetes: A systematic review and meta‐analysis

“…Twelve of these studies compared ABI with angiography (DSA and CTA, no studies used MRA on included participants) ( Table 1) and 21 compared ABI with CDUS (Table 2). Fourteen studies were retrospective [10][11][12][14][15][16][17]22,29,[33][34][35][36][37] and 19 were prospective. 13,[18][19][20][21][23][24][25][26][27][28][30][31][32][38][39][40][41][42]…”

Studying the in vivo microcirculatory adaptation to isometric contraction (dorsiflexion) in the human lower limb

“…In fact, the present study shows that the effect of dorsiflexion over local microcirculation is very similar to that of plantar flexion. This similarity may be explained by the close connections of dorsiflexion with the eccentric contraction of the plantar flexors in the calf and with ankle joint pump [16][17] suggesting that even in the presence of calf muscle weakness, variations in microcirculation may occur by the activity of antagonistic muscles. Since the effect of dorsiflexors during a lack of gastrocnemius activity causes significant differences in distal lower limb perfusion, further studies are necessary to assess its importance as a muscular pump in the return circulation.…”

“…De fato, o presente estudo mostra que o efeito da flexão dorsal sobre a microcirculação local é muito semelhante ao da flexão plantar. Esta situação pode ser explicada pela ligação que a flexão dorsal tem com a contração excêntrica dos flexores plantaras e à bomba situada na articulação do tornozelo [16][17] , sugerindo que mesmo com fraqueza muscular do dos flexores plantares, as variações na microcirculação podem ocorrer pela atividade de seus músculos antagonistas. Uma vez que o efeito dos flexores dorsais durante a baixa atividade dos flexores plantares provoca diferenças significativas na perfusão distal do membro inferior, estudos futuros são necessários para avaliar a sua importância como bomba muscular na circulação de retorno.…”