Matrix metalloproteinases in peripheral vascular disease

Matrix metalloproteinases (MMPs) are extracellular matrix-modifying enzymes that are important in many physiologic and pathologic vascular processes. Dysregulation of MMP activity has been associated with common vascular diseases such as atherosclerotic plaque formation, abdominal aortic aneurysms, and critical limb ischemia. For this reason, MMPs have become an important focus for basic science studies and clinical investigations by vascular biology researchers. This article reviews the recent literature, summarizing our current understanding of the role of MMPs in the pathogenesis of various peripheral vascular disease states. In addition, the importance of MMPs in the future diagnosis and treatment of peripheral vascular disease is discussed.     

Amputations in peripheral vascular occlusive disease

One hundred consecutive patients undergoing major lower extremity amputations were critically analyzed over a five year period. The results of surgical care and the degree of success of rehabilitation were determined. The number of patients with peripheral vascular occlusive disease who require major lower extremity amputations appears to be increasing and they continue to present a challenge to the surgeon.     

Hip disarticulation in peripheral vascular disease

Summary The authors had to perform hip disarticulation on vascular patients in an increasing number — in spite of the general amputation principles. In the majority of the cases hip disarticulation followed other, more distal amputations of the same lower limb. Results of wound-healing, prosthetic fitting and mortality are poor, nevertheless this operation may lengthen life, relieve pain and lead to a tolerable life, usually bound to wheel-chair.

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Zusammenfassung Trotz Beachtung der allgemeinen Amputationsprinzipien sahen sich die Autoren gezwungen, bei Gefäßpatienten in zunehmender Zahl eine Hüftexartikulation vorzunehmen. In der Mehrzahl der Fälle gingen diesem Eingriff an den gleichen Gliedmaßen weiter distal gelegene Amputationen voraus. Die Ergebnisse der Hüftexartikulation hinsichtlich Wundheilung, Prothesenversorgung und Sterblichkeit sind bescheiden. Trotzdem können mit dieser Maßnahme bestehende Schmerzen gebessert und das Leben der Patienten verlängert und erträglicher gestaltet werden, obwohl die Amputierten in der Regel an den Rollstuhl gebunden sind.

     

Near-infrared spectroscopy in peripheral vascular disease

Near-infrared spectroscopy has been performed on the calf muscles of 38 subjects, 21 normal controls without vascular disease and 17 patients with peripheral vascular disease. Oxygen consumption was measured in the calf by calculating the rate of conversion of oxyhaemoglobin to deoxyhaemoglobin during a period of tourniquet-induced ischaemia. Postischaemic reoxygenation was also measured. Median oxygen consumption in patients with peripheral vascular disease was 0.10 ml 100 g tissue-1 min-1, while in the control group it was 0.20 ml 100 g tissue-1 min-1 (P less than 0.03, Mann-Whitney U test). The median time taken to reach maximum oxyhaemoglobin levels after ischaemia was 40 s in patients with peripheral vascular disease and 20 s in controls (P less than 0.02). The results indicate that oxygen consumption is reduced in peripheral vascular disease. Near infrared spectroscopy is a non-invasive method for assessing metabolic improvement resulting from surgical or pharmacological treatment.     

Sympathetic autoregulation in peripheral vascular disease

BACKGROUND: Lower limb venous pressure increases on dependency, stimulating a local sympathetic axon reflex which triggers precapillary and arteriolar vasoconstriction. The resulting decrease in arterial calf inflow, known as the venoarteriolar response (VAR), is impaired in critical leg ischaemia. The aim of the study was to evaluate the VAR in symptomatic non-critical leg ischaemia and after restoration of leg perfusion following successful revascularization. METHODS: The study included 30 normal subjects, 30 patients with stable intermittent claudication and 30 patients with severe ischaemia who had undergone successful infrainguinal revascularization. In all patients the foot skin blood flow (flux) in the horizontal (HBF) and sitting (SBF) positions was measured using laser Doppler fluxmetry. The VAR was calculated as (HBF - SBF)/HBF x 100 per cent. The pressure that elicited the reflex (pVAR) was evaluated in the horizontal position. RESULTS: The median VAR was significantly lower in patients with stable claudication than in normal subjects or patients following successful revascularization (29.1 versus 59.5 and 63.9 per cent respectively; P < 0.0001). Similar results were obtained for the pVAR (22 versus 45 and 40 mmHg respectively; P < 0.001). There was no difference, however, in either the VAR or pVAR between normal individuals and patients following a successful bypass. CONCLUSION: Patients with claudication had a significant impairment of orthostatic sympathetic autoregulation. After successful revascularization, and in spite of the extensive disease in the receiving circulation, this autoregulation returned to normal. Presented previously to the Vascular Surgical Society in London, November 1997 and published in abstract form as Br J Surg 1998; 85: 557     

Hip disarticulation in peripheral vascular disease

The authors had to perform hip disarticulation on vascular patients in an increasing number - in spite of the general amputation principles. In the majority of the cases hip disarticulation followed other, more distal amputations of the same lower limb. Results of wound-healing, prosthetic fitting and mortality are poor, nevertheless this operation may lengthen life, relieve pain and lead to a tolerable life, usually bound to wheel-chair.