Martijn L. Dijkstra3, Rodney J. Lane1, Walid Mohabbat2
1Vascular Surgery, Royal North Shore Hospital, Sydney, NSW, Australia; 2Macquarie University Private Hospital, Sydney, NSW, Australia; 3Dalcross Private Hospital, Sydney, NSW, Australia.
OBJECTIVES: This article reports the early human results of HELP technology in the prevention of major limb amputation due to ischemia. In short-term aim was to dilate pre-existing collateral channels and the long-term aim was to stimulate remodelling and new collateral development by increasing endothelial shear stress.
METHODS: A pilot study consisted of 20 patients with critical limb ischemia. These patients had no other option but major amputation as determined by at least two vascular surgeons. The ischemic limb was isolated from the systemic circulation by the use of an implantable, inflatable, occlusive cuff. The limbs were hyperperfused through arterial access devices with a pump, producing a nonpulsatile waveform at 200% to 300% of the mean arterial pressure (MAP). This was performed intermittently in sessions of 24 to 36 hours and up to a maximum of 74 hours. The primary end point was avoidance of major amputation. The secondary end points were the clinical improvements in rest pain, ulcer healing, and claudication distance. The objective findings include infrared thermography and ultrasound imaging parameters of the limb.
RESULTS: Thirty-nine of 40 connections developed flows 4 to 8 times those supplied to the limb by the normal cardiac output. 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 long term at a mean of 22 months (12-54 months), eight of 20 patients (40%) had avoided major amputation and four more had a delay in amputation of an average of 4 months. The ankle-brachial index changed from 0.11±0.23 to 0.61±0.38 (p<.05). Bleeding, infection, and removal of the access systems and poor patient selection resulted in the failures.
CONCLUSIONS: In selected cases major amputation may be avoided by augmenting the collateral circulation of ischemic limbs using an extracorporeal cardiac pump, occluding balloons and with an access system providing intermittent pump connections.
AUTHOR DISCLOSURES: M. L. Dijkstra, Nothing to disclose; R. J. Lane, Nothing to disclose; W. Mohabbat, Nothing to disclose.
Posted April 2012