Predictive Values of Transcutaneous Oxygen Tension for Above-the-ankle Amputation in Diabetic Patients with Critical Limb Ischemia

OBJECTIVE: To assess the values of transcutaneous oxygen tension (TcPO2) capable of predicting above-the-ankle amputation in diabetic patients diagnosed for critical limb ischemia (CLI) according to the criteria of the TransAtlantic Inter-Society Consensus. DESIGN: Retrospective study. METHODS: From January 1999 to December 2003, 564 diabetic patients were consecutively hospitalized for CLI in one limb. Revascularization with angioplasty or bypass graft was performed when possible and, if not possible, prostanoid therapy was used. In patients in whom therapies did not relieve the rest pain or the gangrene was extended above the Chopart joint, an above-the-ankle-amputation was performed. After treatment TcPO2 values were evaluated in all patients at the dorsum of the foot. RESULTS: Fifty-five (9.8%) patients underwent an above-the-ankle amputation: 22 of 420 patients who underwent angioplasty, 17 of 117 patients who underwent bypass (14.5%) and 16 of 27 patients in whom revascularization was not possible. Post-treatment TcPO2, measured by a receiver operating characteristic (ROC) curve, showed a value 34 mmHg as the best threshold for determining the need for revascularization, with an area under the curve of 0.89 (95%CI 0.85-0.94). Using logistic regression analysis the probability of above-the-ankle amputation for this threshold is 9.7% and reduces to 3% for TcPO2 > 40 mmHg. CONCLUSION: TcPO2 levels<34 mmHg indicate the need for revascularization, while for values >or= 34 < 40 mmHg this need appears less pressing, although there remains a considerable probability of amputation. TcPO2 levels greater than 40 mmHg suggest that revascularization is dependent on the severity of tissue loss and possible morbidity caused by the procedure.     

Treatment for Critical Lower Limb Ischemia in Elderly Patients

Background

Critical limb ischemia (CLI) has a poor outcome when left untreated. The benefits of revascularization in the very elderly might be limited because of co-morbidities and short life expectancy. Therefore, optimal management of CLI in the elderly is not straightforward. We analyzed treatment results for elderly patients with CLI (Rutherford 4 or 5/6) in our clinic.

Methods

Hospital charts of all patients >70 years of age diagnosed with Rutherford stage 4–6 peripheral arterial disease between January 2006 and December 2009 were reviewed. We divided patients into two age groups (70–79 and ≥80 years) to compare treatment results. Primary interventions were defined as conservative, endovascular, reconstructive surgery, and amputation. Outcome measures were mortality, reintervention, and major amputation rates.

Results

There were 191 patients [99 (52 %) were women], median age 78.4 years, range 70–98 years. Altogether, 119 (62 %) patients were aged 70–79 years, and 72 (38 %) were ≥80 years. The primary intervention was equally divided over the two age groups (p = 0.21). Trans-Atlantic Inter-Society Consensus Document on Management of Peripheral Arterial Disease (TASC II) classifications of aortoiliac lesions were not significantly different regarding intervention (p = 0.62) or age (p = 0.39). TASC II classification of femoropopliteal lesions was significantly different relative to intervention (p < 0.01) but not different between age groups (p = 0.68). Mortality rate after reconstructive surgery was significant higher in the oldest age group (p < 0.01). After conservative treatment, endovascular treatment, or amputation, the mortality rates were not significantly different between the two age groups (respectively, p = 0.06, p = 0.33, p = 0.76). Reintervention rate was 51 % in the 70- to 79-year group compared to 32 % in the ≥80-year group. After initial treatment, major amputations were performed in 10 % in the 70- to 79-year group compared to 13 % in the ≥80-year group.

Conclusions

In patients aged ≥80 years, surgical revascularization resulted in a significant higher mortality rate in our clinic, whereas primary conservative, endovascular treatment and amputation resulted in similar mortality in both age groups. When considering surgical revascularization in the very elderly, surgeons should focus on careful patient selection.     

Factors Affecting Patency of Subintimal Infrainguinal Angioplasty in Patients with Critical Lower Limb Ischemia

BACKGROUND: Because subintimal angioplasty (SA) is a technique that can achieve recanalization of long arterial occlusions, it is considered an alternative to lower limb bypass operations. The aim of this prospective study was to identify the risk factors that affect patency of SA in patients suffering from critical limb ischemia (CLI). METHODS AND RESULTS: 51 consecutive infrainguinal SA were done in 46 patients suffered from CLI. The patients were followed-up with regular duplex scans up to 12 months post-intervention. Sex, atherosclerosis risk factors, and some technical details of the procedure (number of patent run-off vessels after the procedure, length and re-entry point of angioplasty) were examined as potential risk factors of patency, using survival analysis statistical techniques. The overall patency rate at 12 months post-intervention was 50%. According to Cox-regression analysis, the factors that affect patency were the number of run-off vessels and the length of occlusion. Patients with two or three run-off vessels had a hazard of occlusion of 0.30 (P = .027) compared to those who had one run-off vessel. The 12-months patency in patients with more than one run-off vessels was 81% vs. 25% in patients with one run-off vessel. Regarding the length of angioplasty, the hazard of reocclusion was 1.02 for every centimeter of occlusion (P = .049). CONCLUSIONS: The number of patent run-off crural vessels after the angioplasty and the length of occlusion are significant risk factors for reocclusion of infrainguinal SA in patients with CLI. Trying to recanalize more than one run-off vessels could raise the SA patency.     

Primary and Secondary Amputation in Critical Limb Ischemia Patients: Different Aspects

The TASC II working group reports on primary amputation incidence rates vary between 12 and 50 per 100,000 per year. The primary amputation rate does not only depend on co-morbidities like diabetes and PAD, but also on local factors like the regional availability of vascular surgeons and interventional radiologists and their case load. Further-more, several studies could show that increasing revascularisation rates have drastically reduced amputation rates in the US, with a 50% decrease in amputation rates during a 10 year study period and a corresponding increase in surgical and endovas-cular revascularisation rates. An analysis of national and state US databases confirmed a drop in major amputations and open surgical revascularisations, in favour of an increase in endovascular interventions. The same study observed an increase in minor amputations during the same period. However, it remains unclear whether this trend is a consequence of the increased usage of endovascular procedures in high-risk patients who are unfit for open surgery or of earlier endovas-cular intervention in less critical lesions. This review gives an overview of the incidence, indication, amputation-level finding and outcome of major amputations performed in critical limb ischemia (CLI) patients.