Balloon occlusion of the superficial femoral artery at rest increased pressure-derived collateral flow index from 0.451 to 0.551 (P=0.0003), but exercise caused a decline to 0.347 (P<0.0001).
Can collateral arterial function of the lower limb be quantitatively assessed using pressure-derived collateral flow index in patients undergoing angiography?
Direct quantitative assessment of peripheral artery collateral circulation using pressure-derived collateral flow index is feasible and reveals a supply-demand mismatch during exercise.
p-value: p=0.0003
BACKGROUND: Despite the fact that numerous studies have pursued the strategy of improving collateral function in patients with peripheral artery disease, there is currently no method available to quantify collateral arterial function of the lower limb. METHODS AND RESULTS: Pressure-derived collateral flow index (CFIp, calculated as (occlusive pressure-central venous pressure)/(aortic pressure-central venous pressure); pressure values in mm Hg) of the left superficial femoral artery was obtained in patients undergoing elective coronary angiography using a combined pressure/Doppler wire (n=30). Distal occlusive pressure and toe oxygen saturation (Sao2) were measured for 5 minutes under resting conditions, followed by an exercise protocol (repetitive plantar-flexion movements in supine position; n=28). In all patients, balloon occlusion of the superficial femoral artery over 5 minutes was painless under resting conditions. CFIp increased during the first 3 minutes from 0.451±0.168 to 0.551±0.172 (P=0.0003), whereas Sao2 decreased from 98±2% to 93±7% (P=0.004). Maximal changes of Sao2 were inversely related to maximal CFIp (r(2)=0.33, P=0.003). During exercise, CFIp declined within 1 minute from 0.560±0.178 to 0.393±0.168 (P<0.0001) and reached its minimum after 2 minutes of exercise (0.347±0.176), whereas Sao2 declined to a minimum of 86±6% (P=0.002). Twenty-five patients (89%) experienced pain or cramps/tired muscles, whereas 3 (11%) remained symptom-free for an occlusion time of 10 minutes. CFIp values were positively related to the pain-free time span (r(2)=0.50, P=0.002). CONCLUSIONS: Quantitatively assessed collateral arterial function at rest determined in the nonstenotic superficial femoral artery is sufficient to prevent ischemic symptoms during a total occlusion of 5 minutes. During exercise, there is a decline in CFIp that indicates a supply-demand mismatch via collaterals or, alternatively, a steal phenomenon. CLINICAL TRIAL REGISTRATION-URL: http://www.clinicaltrials.gov. UNIQUE IDENTIFIER: NCT01742455.
Traupe et al. (Tue,) conducted a other in Patients undergoing elective coronary angiography (n=30). Balloon occlusion of the superficial femoral artery was evaluated on Pressure-derived collateral flow index (CFIp) and toe oxygen saturation (Sao2) (p=0.0003). Balloon occlusion of the superficial femoral artery at rest increased pressure-derived collateral flow index from 0.451 to 0.551 (P=0.0003), but exercise caused a decline to 0.347 (P<0.0001).