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While conventional thermographic applications to the human body aim at revealing local temperature changes normally related with the beginning of a pathologic process, this paper shows how lockin thermography can be modified in order to meet medical needs in the visualization of functionality of blood vessels. A compression cuff is used in connection with the lockin system to create a modulation in the blood flow. The amplitude and phase images thus obtained can provide infonmation about the blood flow in the vessels.

Perigraft reaction can be defined as an aseptic biological incompatibility of synthetic vascular prostheses. The clinical picture is characterized by an indolent fluctuating swelling around the prosthesis, consisting of sterile fluid surrounded by a fibrous capsule. Since 1979, a total Of 22 perigraft reactions in 2,554 implanted vascular grafts were observed and analyzed. The incidence of this complication is about 8/1,000 both for Dacron | double-velour and expanded polytetrafluoroethylene (PTFE). Including 306 reports from the literature, prostheses in the extraanatomical position comprise nearly 75% of the material analyzed. The time interval between graft implantation and clinical manifestation is, on average, 25 months. Although the etiology is still unclear, the pathogenesis is supposed to be multifactoriah (a) there is mechanical trauma due to continuous shifting of the prosthesis in the surrounding tissue (especially in the case of extraanatomic grafts), (b) there is physicochemical irritation of the tissue bed by the graft material (velour surface, organic solvents), and (c) poor incorporation of the graft may lead to periprosthetic gap formation and fluid accumulation around the prosthesis. Infections, or immunologic or allergic causes can be excluded. Therapy includes total or partial replacement of the affected portion of the graft and cyst wall with substitution by a prosthesis of a different synthetic material. Repeated aspiration of the periprosthetic cyst should be avoided because of the high failure rate and danger of secondary infection.

Heparin-induced thrombocytopenia type II (HIT type II) is an immunoglobulin-mediated, drug-induced side effect for heparin-treated patients with thromboembolic complications. With an incidence of 1-3 %, mortality of 20 % it and permanent disability for another 20 % is a clinically relevant disorder. With heparin treatment or prophylaxis frequent platelet count monitoring is necessary. With HIT type II the thrombocytopenia is often a harbinger of thromboembolic complications in the venous or arterial system. If HIT type II is suspected, further heparin exposure is to be stopped immediately and another anticoagulant therapy should be started. The two anticoagulant options in Germany are discussed. At the same time the diagnosis should be confirmed by laboratory testing, including testing for cross-reactivity with danaparoid. Further therapy depends on the symptoms. In the case of clinical relevance of this disorder we should think about prophylaxis: strict indications for perioperative prophylaxis only use of low-molecular-weight heparin (LMWH) for routine prophylaxis, use of LMWH for thrombosis treatment and early change to cumarine.

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