Spinal cord stimulation for patients with inoperable chronic critical leg ischemia

Treatment of end-stage peripheral artery disease by Neuromodulation

BACKGROUND: Neuromodulation is a therapeutic option to improve limb salvage in end-stage peripheral arterial disease (PAD), but there is no consensus on indication for spinal cord stimulation (SCS) in PAD patients. OBJECTIVE: The aim of this study was to present end-stage PAD patient outcomes treated with SCS. METHODS: This study is a retrospective analysis based on a local prospective registry. Neuromodulation was performed there was: [1] no revascularisation option, [2) no septicaemia, [3) Rutherford stage 4–6. The primary endpoint of the study was limb salvage. Secondary endpoints were improvement in pain symptoms (assessed using a visual anlog scale/VAS) and improvement in walking distance. RESULTS: Limb salvage was reached in 30/34 patients (88%). Patients reported a significant reduction in pain on the 10-point VAS scale from baseline (median = 7.5, IQR = 7–8) to follow-up at 2 years (median = 0, IQR 0–2.75), p <  0.001. Walking distance also improved from preoperative (median = 50 m, IQR = 20–50 m) to follow-up at 2 years (median = 150 m, IQR 50–272 m), p <  0.001. RESULTS: SCS implantation in patients with end-stage PAD can enable limb salvage in a high percentage of cases and increase mobility due to pain reduction. The role of microcirculation in these improvements needs to be investigated in further studies.

[Chronic spinal stimulation in treatment of lower limb critical ischaemia syndrome]

Obliterating peripheral artery disease is a commonly occurring pathological condition, most often resulting from an atherosclerotic lesion of vessels with progressive narrowing of their lumens. The consequences of decompensation of chronic arterial insufficiency such as ischaemic pain, claudication, and trophic impairments are in some instances difficult to treat, despite using multicomponent medicamentous therapy and/or performing revascularizing interventions. This article describes a clinical case report regarding the use of spinal stimulation in a patient presenting with stage IV chronic lower limb ischaemia according to the Fontaine classification. This is accompanied and followed by depicting the dynamics of the laboratory, instrumental, and clinical parameters over a two-year follow-up period. In order to explain the choice of the intervention and the causes of the described picture, discussed are the existing theories of the mechanisms of action of spinal stimulation. To this is added a literature review of using this method in treatment of lower limb critical ischaemia when performing reconstructive angiosurgical treatment is unavailable. Mention is also made of the incidence and types of probable complications, as well as possibilities and limitations of the method.

The Effects of Spinal Cord Stimulators on End Organ Perfusion: A Literature Review

Spinal cord stimulators (SCS) have been gaining momentum in the last decade as their role in the management of chronic pain has become more apparent. Our intention was to search, analyze and highlight the effects of spinal cord stimulators on end-organ perfusion. We also looked at vascular diseases of atherosclerotic and nonatherosclerotic nature by examining objective evidence of improved circulation, pain control, limb salvage, and quality of life. We paid specific attention to disease processes such as cerebral hypoperfusion, Chronic-Critical Limb Ischemia, Intractable Angina Pectoris (IAP), Raynaud’s syndrome and Thromboangiitis Obliterans.

We performed a Medline database search for medical literature relevant to Spinal cord stimulators encompassing the years 1950 to 2019. Search terms included “Spinal cord stimulator,” plus one of the following search terms: vasculopathy, stroke, cerebral blood flow, angina pectoris, diabetic ulcers, chronic critical leg ischemia, thromboangiitis obliterans and peripheral vascular disease. We included both clinical and experimental human studies that investigated the effect of SCS’s on end-organ perfusion. We also investigated the pathophysiological mechanism of action of SCS’s on the vasculature. We found 497 articles of which 43 more relevant and impactful articles investigating the hemodynamic effects of SCS and its possible mechanism were selected. Animal studies were excluded from the literature review as they provided heterogeneity. In addition to reporting literature supporting the use of stimulators for currently FDA approved uses, we also actively looked for potential future uses. Spinal Cord stimulators showed improvement in cerebral blood flow, increased capillary recruitment, and better quality of life in many studies. Patients also had increased exercise capacity and a significant reduction in the use of narcotic drug use and daily anginal attacks in patients suffering from IAP.

Activation of SK/KCa Channel Attenuates Spinal Cord Ischemia-Reperfusion Injury via Anti-oxidative Activity and Inhibition of Mitochondrial Dysfunction in Rabbits

Spinal cord ischemia-reperfusion injury (SCI/R) is a rare but devastating disorder with a poor prognosis. Small conductance calcium-activated K⁺ (SK/K_Ca) channels are a family of voltage-independent potassium channels that are shown to participate in the pathological process of several neurological disorders. The aim of this study was to investigate the role of SK/K_Ca channels in experimental SCI/R in rabbits. The expression of SK/K_Ca1 protein significantly decreased in both cytoplasm and mitochondria in spinal cord tissues after SCI/R. Treatment with 2 mg/kg NS309, a pharmacological activator for SK/K_Ca channel, attenuated SCI/R-induced neuronal loss, spinal cord edema and neurological dysfunction. These effects were still observed when the administration was delayed by 6 h after SCI/R initiation. NS309 decreased the levels of oxidative products and promoted activities of antioxidant enzymes in both serum and spinal cord tissues. The results of ELISA assay showed that NS309 markedly decreased levels of pro-inflammatory cytokines while increased anti-inflammatory cytokines levels after SCI/R. In addition, treatment with NS309 was shown to preserve mitochondrial respiratory complexes activities and enhance mitochondrial biogenesis. The results of western blot analysis showed that NS309 differentially regulated the expression of mitochondrial dynamic proteins. In summary, our results demonstrated that the SK/K_Ca channel activator NS309 protects against SCI/R via anti-oxidative activity and inhibition of mitochondrial dysfunction, indicating a therapeutic potential of NS309 for SCI/R.

The Clinical Outcomes in Patients with Critical Limb Ischemia One Year after Spinal Cord Stimulation

BACKGROUND

The aim of this study was to evaluate the long-term outcomes of spinal cord stimulation in patients with critical limb ischemia and to test the hypothesis that the dynamics of clinical changes one year after therapy depend both on the clinical determinants associated with the underlying disease and on factors related to systemic atherosclerosis.

METHODS

This prospective cohort study included 56 patients with critical limb ischemia. All patients before and after spinal cord stimulation were examined in terms of the dynamics of their clinical changes using the Rutherford scale and transcutaneous oxygen tension (TcPO₂, mm Hg) in the affected foot. The active orthostatic test was used to assess the functional state of peripheral perfusion.

RESULTS

One year after spinal cord stimulation, 74% of patients showed positive clinical outcomes. No changes were observed in 9.3% of patients, whereas adverse clinical outcomes were revealed in 16.7% of cases. The TcPO₂ values were significantly reduced before spinal cord stimulation: 10.5 (6.4-16.0) mm Hg. The functional status of the peripheral microvasculature was also disturbed. One year after therapy, TcPO₂ significantly increased and the adaptive mechanisms of the microvasculature were improved in more than 70% of patients. Logistic regression analysis showed that the initially low TcPO₂ values (<10 mm Hg) with a lack of gain in TcPO₂ during the orthostatic test are associated with the negative clinical outcomes after spinal cord stimulation. The gain in TcPO₂ during the orthostatic test to >10 mm Hg is associated with the positive clinical outcomes after spinal cord stimulation. The age-adjusted Charlson Comorbidity Index >5 and duration of critical ischemic symptoms also had a negative effect on the clinical outcomes after spinal cord stimulation.

CONCLUSIONS

The positive clinical outcomes were revealed in most patients with critical limb ischemia one year after spinal cord stimulation. The low values of peripheral tissue metabolism with the disturbed functional status of the microvasculature are associated with the negative clinical outcome. The patients with baseline TcPO₂ <10 mm Hg can recover if they still have a sufficient microcirculatory reserve capacity. Duration of critical ischemic symptoms and high comorbidity burden with allowance for age are negative factors affecting the clinical outcome.

Stem Cell Therapies in Peripheral Vascular Diseases — Current Status

Peripheral artery diseases include all arterial diseases with the exception of coronary and aortic involvement, more specifically diseases of the extracranial carotids, upper limb arteries, mesenteric and renal vessels, and last but not least, lower limb arteries. Mononuclear stem cells, harvested from various sites (bone marrow, peripheral blood, mesenchymal cells, adipose-derived stem cells) have been studied as a treatment option for alleviating symptoms in peripheral artery disease, as potential stimulators for therapeutic angiogenesis, thus improving vascularization of the ischemic tissue. The aim of this manuscript was to review current medical literature on a novel treatment method — cell therapy, in patients with various peripheral vascular diseases, including carotid, renal, mesenteric artery disease, thromboangiitis obliterans, as well as upper and lower limb artery disease.