The collateral circulation of ischemic limbs can be augmented and regulated by a connection to an extracorporeal centrifugal pump, with isolation from the systemic circulation provided by balloons and with an access system providing repeatable pump connections. Major amputation may be avoided in selected cases.

Blood flow through collaterals can be very significantly augmented by connection to an extracorporeal pump with isolation from the systemic circulation. The pancycle hyperperfusion can be safely repeated by implantation of an arterial access device. In the longer term, there is evidence of collateral development. When amputation is the only alternative, hypertensive extracorporeal limb perfusion should be considered.

titles with an asterisk were judged for the RACS/?? Research Prize for Trainees.Objective: To report the early human results of H.E.L.P. technology in the prevention of major limb amputation. In the short-term, the aim was to pressure dilate collateral channels and in the long-term to stimulate remodelling and new collateral pathways by increasing endothelial shear stress. Methods: A pilot study consisted of the ischaemic limbs of 15 patients with critical limb ischaemia. These patients had no other option but major amputation as determined by at least two vascular surgeons. The limbs were connected to a commercially available cardiac pump via an access system. The limbs were hyperperfused pancycle at 2-3 times the mean arterial pressure (MAP). This was performed intermittently in sessions of 24-36 hours. The major endpoint was avoidance of major amputation. Results: Given adequate arterial access, 29 of 30 connections developed flows 4-8 times the MAP. There was a progressive decrease in peripheral resistance. All patients developed a pain-free, warm foot or hand whilst on the pump in the short-term. In the longer term, a mean of 10.4 months (range 1-29 months) 50% had avoided major amputation. Pain scores changed from 0.9 ± 0.1 to 1.1 ± 1.3 under the visual analogue scale (V.A.S). The ankle brachial index (A.B.I) changed from 0.06 ± 0.09 to 0.57 ± 0.33, p < 0.05 (t test). Conclusions: The collateral circulation of ischaemic limbs can be augmented and regulated via connection to an extracorporeal cardiac pump. The technique is similar to haemodialysis. Major amputation can be avoided in selective cases. Improvements in the technology are continuing.