Management of chronic critical limb ischemia

Critical Limb Ischemia: A Practical Up-To-Date Review

Critical limb ischemia (CLI) is the most advanced form of peripheral artery disease. It is associated with significant morbidity and mortality and high management costs. It carries a high risk of amputation and local infection. Moreover, cardiovascular complications remain a major concern. Although it is a well-known entity and new technological and therapeutic advances have been made, this condition remains poorly addressed, with significantly heterogeneous management, especially in nonexperienced centers. This review, from a third-level dedicated inpatient and outpatient cardioangiology structure, aims to provide an updated summary on the topic of CLI of its complexity, encompassing epidemiological, social, economical and, in particular, diagnostic/imaging issues, together with potential therapeutic strategies (medical, endovascular, and surgical), including the evaluation of cardiovascular risk factors, the diagnosis, and treatment together with prognostic stratification.

Treprostinil Sodium (Remodulin), a Prostacyclin Analog, in the Treatment of Critical Limb Ischemia: Open-Label Study

The purpose of this study was to assess the safety of continuous subcutaneous therapy with treprostinil sodium (Remodulin), a prostacyclin analog, and its effect on ischemic rest pain and ischemic wound healing in subjects with critical limb ischemia (CLI) and no planned revascularization procedure.

This was a 12-week, open-label, single-center pilot study enrolling 10 subjects (mean age 82.4 years) with Fontaine stage III to IV (Rutherford class 4–6) peripheral arterial disease and ankle brachial indices less than 0.55. The primary end point was safety, and the secondary end points were the effects of treatment on ischemic rest pain, limb salvage, and wound healing.

There was a 62% reduction in mean worst rest pain and a 57% reduction in mean average rest pain at week 12, with most subjects using less pain medication. Three subjects experienced complete healing of their wounds. No subject developed a new wound during the trial. Treprostinil was generally well tolerated. Subcutaneous infusion-site pain was the most frequently reported side effect, with one subject withdrawing from the study as a result. Jaw pain was reported by two subjects. One subject experienced two serious adverse events considered unrelated to treprostinil (cholecystitis and congestive heart failure).

This study demonstrates that chronic, continuous subcutaneous treprostinil is safe and can be useful in the treatment of ischemic pain and wounds in subjects with CLI. Future controlled studies are needed to evaluate these effects and determine appropriate patient selection.

Critical and acute limb ischemia: an overview

Some patients with peripheral arterial disease may present with critical limb ischemia, a condition associated with high rates of morbidity and mortality. Early diagnosis and effective medical therapy and revascularization are indicated to avoid amputation and reduce mortality. Ideally, a multidisciplinary approach with collaboration between endovascular interventionist, vascular surgeons, podiatrist, infectious disease, and wound care specialist is recommended for these patients.

Diabetic foot wounds in haemodialysis patients: 2-year outcome after percutaneous transluminal angioplasty and minor amputation

Critical limb ischaemia (CLI) is known to be associated with high mortality. In some patients, surgery cannot be performed due to high risk of perioperative death and complications. In other cases, there is only pain at rest but no wound. Therefore, it is difficult to accurately predict the prognosis of individual patients. We examined the prognosis of CLI cases in which therapeutic footwear was made for ambulation after wounds healed. The subjects were 31 haemodialysis patients with diabetic foot wounds, which were treated with percutaneous transluminal angioplasty and minor amputation. The subjects were 22 men and 9 women. Female patients were significantly older than male patients (P = 0.046). Two-year postoperative outcomes were survival in 19 patients and death in 12 patients. Eight of twelve deceased patients had a history of coronary intervention. There were 8 deaths among 13 patients with such history, indicating a marginally significant increase in the mortality rate (P = 0.060). Re-amputation was performed in 6 of 19 patients who survived. Two years postoperatively, 41.9% of patients overall survived without re-amputation. It is important to increase the number of cases for further study to improve the well-being of CLI patients and to examine medical economics.

Chapter I: Definitions, epidemiology, clinical presentation and prognosis

The concept of chronic critical limb ischaemia (CLI) emerged late in the history of peripheral arterial occlusive disease (PAOD). The historical background and changing definitions of CLI over the last decades are important to know in order to understand why epidemiologic data are so difficult to compare between articles and over time. The prevalence of CLI is probably very high and largely underestimated, and significant differences exist between population studies and clinical series. The extremely high costs associated with management of these patients make CLI a real public health issue for the future. In the era of emerging vascular surgery in the 1950s, the initial classification of PAOD by Fontaine, with stages III and IV corresponding to CLI, was based only on clinical symptoms. Later, with increasing access to non-invasive haemodynamic measurements (ankle pressure, toe pressure), the need to prove a causal relationship between PAOD and clinical findings suggestive of CLI became a real concern, and the Rutherford classification published in 1986 included objective haemodynamic criteria. The first consensus document on CLI was published in 1991 and included clinical criteria associated with ankle and toe pressure and transcutaneous oxygen pressure (TcPO(2)) cut-off levels <50 mmHg, <30 mmHg and <10 mmHg respectively). This rigorous definition reflects an arterial insufficiency that is so severe as to cause microcirculatory changes and compromise tissue integrity, with a high rate of major amputation and mortality. The TASC I consensus document published in 2000 used less severe pressure cut-offs (≤ 50-70 mmHg, ≤ 30-50 mmHg and ≤ 30-50 mmHg respectively). The thresholds for toe pressure and especially TcPO(2) (which will be also included in TASC II consensus document) are however just below the lower limit of normality. It is therefore easy to infer that patients qualifying as CLI based on TASC criteria can suffer from far less severe disease than those qualifying as CLI in the initial 1991 consensus document. Furthermore, inclusion criteria of many recent interventional studies have even shifted further from the efforts of definition standardisation with objective criteria, by including patients as CLI based merely on Fontaine classification (stage III and IV) without haemodynamic criteria. The differences in the natural history of patients with CLI, including prognosis of the limb and the patient, are thus difficult to compare between studies in this context. Overall, CLI as defined by clinical and haemodynamic criteria remains a severe condition with poor prognosis, high medical costs and a major impact in terms of public health and patients' loss of functional capacity. The major progresses in best medical therapy of arterial disease and revascularisation procedures will certainly improve the outcome of CLI patients. In the future, an effort to apply a standardised definition with clinical and objective haemodynamic criteria will be needed to better demonstrate and compare the advances in management of these patients.

Sustained release of multiple growth factors from injectable polymeric system as a novel therapeutic approach towards angiogenesis

Purpose

The aim was to investigate that a bio-degradable alginate and poly lactide-co-glycolide (PLG) system capable of delivering growth factors sequentially would be superior to single growth factor delivery in promoting neovascularization and improving perfusion.

Methods

Three groups of apoE null mice underwent unilateral hindlimb ischemia surgery and received ischemic limb intramuscular injections of alginate (Blank), alginate containing VEGF₁₆₅ (VEGF), or alginate containing VEGF₁₆₅ combined with PLG microspheres containing PDGF-BB (VEGF/PDGF). Vascularity in the ischemic hindlimb was assessed by morphologic and immunohistochemical end-points, while changes in blood flow were assessed by Laser Doppler Perfusion Index. Muscle VEGF and PDGF content was assessed at multiple time points.

Results

In the VEGF/PDGF group, local tissue VEGF and PDGF levels peaked at week 2 and 4, respectively, with detectable PDGF levels at week 6. At week 6, mean vessel mean diameter was significantly greater in the VEGF/PDGF group compared to the VEGF or Blank groups with evidence of well-formed smooth muscle-lined arterioles.

Conclusions

Sequential delivery of VEGF and PDGF using an injectable, biodegradable platform resulted in stable and sustained improvements in perfusion. This sustained, control-released, injectable alginate polymer system is a promising approach for multiple growth factor delivery in clinical application.

Interventional management of critical limb ischemia in renal patients

Critical limb ischemia (CLI) represents the most severe clinical manifestation of peripheral arterial disease (PAD), defined as the presence of chronic ischemic rest pain, ulcers, or gangrene attributable to objectively proven arterial occlusive disease. The occurrence of CLI in patients with kidney insufficiency portends a strikingly high rate of subsequent morbidity and mortality. Generally, the primary therapy for CLI is revascularization of the affected limb. However, patients with CLI and kidney insufficiency represent a unique and challenging patient subset, and data from surgical series suggest reduced rates of limb salvage and higher medium and long-term mortality rates for patients with kidney insufficiency compared with those with normal kidney function. In contemporary practice, endovascular techniques are fast replacing surgical bypass as the first-line revascularization strategy for CLI, based on high technical success rates and low rates of procedure-related morbidity and mortality. However, a large series on endovascular outcomes for the treatment of CLI in patients with kidney insufficiency is lacking. Based on the severely reduced long-term survival rates of patients with CLI and kidney insufficiency, future efforts should focus on early detection of PAD in patients with kidney insufficiency and institution of aggressive medical therapy to prevent progression in the global burden of atherosclerosis in this patient population.

[Chronic critical ischemia of the legs. Definition and management]

The term "Chronic critical ischemia ", CCI, of lower limb defines a very advanced state of chronic LL arterial insufficiency with deleterious effect of low perfusion pressure rate. This diagnosis has serious consequences for the patient (high risk of major amputation, high risk of cardiovascular events and death, high risk of reduced quality of life for survivals even non-amputated). The diagnosis must be precise. We discuss the evolution of the concept and the definitions of CCI from Fontaine classification, the epidemiology of CCI and its risk factors, the diagnosis of CCI (clinical, haemodynamical, anatomical) and the treatment of CCI which the main goal is to increase as much as possible the arterial pressure in the foot.

Worsening of chronic pain: the treatment

Chronic pain is a symptom that inevitably goes along with a condition of critical ischemia of the lower limbs, termed also as "obstructive peripheral arteriopathy". This sometimes displays worsening, provoking difficult physical and psychological behaviors of the patients. The complexity of this kind of patients results in difficulties in their clinical management. A multidisciplinary team, namely the close and coordinated collaboration of various kinds of professionists, could give better results, than an individual approach, thanks to strategies of re-equilibrating the systemic homeostasis of the given patient.