Treatment of infrapopliteal critical limb ischemia in 2013: the wound perfusion approach

A systematic review of patient-reported outcome measures patients with chronic limb-threatening ischemia

Chronic limb-threatening ischemia (CLTI) causes significant morbidity with profound negative effects on health-related quality of life. As the prevalence of peripheral artery disease and diabetes continue to rise in our aging population, the public health impact of CLTI has escalated. Patient-reported outcome measures (PROMs) have become common and important measures for clinical evaluation in both clinical care and research. PROMs are important for the measurement of clinical effectiveness and cost effectiveness and for shared decision-making on treatment options. However, the PROMs used to describe the experience of patients with CLTI are heterogeneous, incomplete, and lack specific applicability to the underlying disease processes and diverse populations. For example, certain PROMs exist for patients with extremity wounds, and other PROMs exist for patients with pain, and still others exist for patients with vascular disease. Despite this multiplicity of tools, no single PROM encompasses all of the components necessary to describe the experiences of patients with CLTI. This significant unmet need is evident from both published reports and contemporary large-scale clinical trials in the field. In this systematic review, we review the current use of PROMs for patients with CLTI in clinical practice and in research trials and highlight the gaps that need to be addressed to develop a unifying PROM instrument for CLTI.

Quantifying tissue perfusion after peripheral endovascular procedures: Novel tissue perfusion endpoints to improve outcomes

Peripheral artery disease (PAD) is a flow-limiting condition caused by narrowing of the peripheral arteries typically due to atherosclerosis. It affects almost 200 million people globally with patients either being asymptomatic or presenting with claudication or critical or acute limb ischemia. PAD-affected patients display increased mortality rates, rendering their management critical. Endovascular interventions have proven crucial in PAD treatment and decreasing mortality and have significantly increased over the past years. However, for the functional assessment of the outcomes of revascularization procedures for the treatment of PAD, the same tests that have been used over the past decades are still being employed. Those only allow an indirect evaluation, while an objective quantification of limb perfusion is not feasible. Standard intraarterial angiography only demonstrates post-intervention vessel patency, hence is unable to accurately estimate actual limb perfusion and is incapable of quantifying treatment outcome. Therefore, there is a significant necessity for real-time objectively measurable procedural outcomes of limb perfusion that will allow vascular experts to intraoperatively quantify and assess outcomes, thus optimizing treatment, obviating misinterpretation, and providing significantly improved clinical results. The purpose of this review is to familiarize readers with the currently available perfusion-assessment methods and to evaluate possible prospects.

Perfusion Assessment in Critical Limb Ischemia: Principles for Understanding and the Development of Evidence and Evaluation of Devices: A Scientific Statement From the American Heart Association

There are >12 million patients with peripheral artery disease in the United States. The most severe form of peripheral artery disease is critical limb ischemia (CLI). The diagnosis and management of CLI is often challenging. Ethnic differences in comorbidities and presentation of CLI exist. Compared with white patients, black and Hispanic patients have higher prevalence rates of diabetes mellitus and chronic renal disease and are more likely to present with gangrene, whereas white patients are more likely to present with ulcers and rest pain. A thorough evaluation of limb perfusion is important in the diagnosis of CLI because it can not only enable timely diagnosis but also reduce unnecessary invasive procedures in patients with adequate blood flow or among those with other causes for ulcers, including venous, neuropathic, or pressure changes. This scientific statement discusses the current tests and technologies for noninvasive assessment of limb perfusion, including the ankle-brachial index, toe-brachial index, and other perfusion technologies. In addition, limitations of the current technologies along with opportunities for improvement, research, and reducing disparities in health care for patients with CLI are discussed.

Six-Month Freedom From Amputation Rates and Quality of Life Following Tibial and Pedal Endovascular Revascularization for Critical Limb Ischemia

Objective:

Patients with critical limb ischemia (CLI) and gangrene have a 10% to 38% rate of major amputation at 6 months. The purpose of this study is to report short- and mid-term major and minor amputation rates for patients who underwent tibial and pedal revascularization in addition to quality-of-life (QoL) scores.

Methods:

All patients who presented to a single institution with CLI (defined as rest pain or nonhealing wounds) and underwent antegrade or retrograde tibial access, atherectomy and angioplasty of the tibial circulation, and angioplasty of pedal circulation (antegrade or retrograde) from June 2016 to September 2017 were included. The Stark QoL questionnaire was used at each visit. Patients were scored at 1, 3, and 6 months postprocedure. Amputation rates were recorded.

Results:

Forty-two patients with CLI and gangrene underwent 57 peripheral interventions for limb salvage between June 2016 and September 2017. Thirty-two limbs had dry gangrene along the dorsalis pedis angiosome, 14 limbs had dry gangrene along the posterior tibial angiogram, and 11 limbs had a combined disease pattern. Twelve limbs underwent angioplasty of the superficial femoral artery (SFA), 18 limbs underwent angioplasty and stenting of the SFA, and 14 limbs underwent atherectomy, angioplasty, and stenting of the SFA. All patients had 1 or 2 tibial vessel runoff and high-grade stenosis of the pedal circulation. Immediate technical success defined as 3-vessel outflow to the foot occurred in 49 limbs (86%) with zero 30-day complications (30-day readmission, major amputation, or sepsis). Major amputation rate at 1, 3, and 6 months was 0%, 2%, and 4%, respectively. Patient satisfaction in terms of QoL increased over the 6-month follow-up period.

Conclusion:

Aggressive tibial and pedal revascularization may improve freedom from minor and major amputation at 6 months and may be associated with a short- and mid-term higher QoL.

Heterogeneity of Ankle-Brachial Indices in Patients Undergoing Revascularization for Critical Limb Ischemia

OBJECTIVES

This study sought to describe the distribution of pre-intervention treated-limb ankle-brachial indices (ABIs) among patients with critical limb ischemia (CLI) undergoing percutaneous vascular intervention (PVI) or surgical revascularization (SR).

BACKGROUND

CLI is diagnosed by the presence of rest pain, tissue ulceration, or gangrene due to chronic arterial insufficiency. It is unclear what fraction of patients with suspected CLI have severe peripheral artery disease (PAD) on noninvasive functional testing.

METHODS

The study included patients who underwent lower extremity revascularization for CLI in a multicenter registry in Michigan from January 2012 through June 2015. ABIs were classified as normal (ABI: 0.91 to 1.40), mild-moderate (ABI: 0.41 to 0.90), and severe (ABI: ≤0.40). Pre- and post-intervention Peripheral Artery Questionnaire summary scores were assessed in a subset of patients.

RESULTS

Among 10,756 patients with signs or symptoms of CLI, 9,113 (84.7%) underwent PVI and 1,643 (15.3%) underwent SR. ABIs were recorded in 4,972 (54.6%) PVI and 1,012 (61.6%) SR patients. Patients undergoing PVI had higher ABIs than those undergoing SR, with substantial variation in both groups (PVI: 0.72 ± 0.29 vs. SR: 0.61 ± 0.29; p < 0.001). Nearly a quarter of patients with compressible arteries had normal ABIs (24.0%), whereas severe PAD was uncommon (16.5%). A significant improvement in Peripheral Artery Questionnaire scores was noted after intervention across all ABI categories.

CONCLUSIONS

Among patients undergoing revascularization for CLI in contemporary practice, the authors found substantial heterogeneity in pre-intervention ABIs. The disconnect between ABI results and clinical diagnosis calls into question the utility of ABIs in this population and suggests the need for standardization of functional PAD testing.

Percutaneous Therapies for Peripheral Artery Disease

Percutaneous therapies for peripheral artery disease continue to evolve with new techniques and devices. Although guidelines-recommended therapies have impacted cardiovascular morbidity and mortality, endovascular interventions have been shown to reduce limb pain, improve quality of life, and prolong walking distance for those with claudication and to reduce amputation rates among those with critical limb ischemia. Novel devices such as drug-eluting stents and drug-coated balloons have improved patency for moderate-length lesions, whereas others allow treatment of heavily calcified and tortuous segments. New adjunctive devices to cross lesions and reduce or modify associated plaque have also been developed, although level 1 data regarding their efficacy are sparse. There has also been a better mechanistic understanding of lower extremity endovascular treatment using tools such as intravascular ultrasound. This information has highlighted the need for better stent size selection for the femoropopliteal arterial segments and larger balloon diameters for the tibial arteries. Moreover, a wound perfusion approach with direct in-line flow, the so-called angiosome approach, and reconstruction of the pedal loop have been advocated for improved wound healing. Technical advances such as the tibiopedal access and reentry methods have allowed crossing of lesions that were considered no option for the endovascular approach in the past. Collectively, there has been increased awareness, interest, and commitment by various specialty societies and organizations to advance the treatment of peripheral artery disease and critical limb ischemia. This is also evident by the recent coalition of 7 professional societies and organizations that represented >150 000 allied health professionals and millions of patients with peripheral artery disease at the 2015 Centers for Medicaid and Medicare Services Medicare Evidence Development and Coverage Analysis Committee meeting. The percutaneous therapies for peripheral artery disease continue to evolve with longer follow-up with randomized data and larger prospective registries. In the future, it is hopeful that we will treat the lower extremity arteries according to segments, taking into account plaque morphology, luminal versus subintimal crossing, location, and stenotic versus occlusive disease. Until then, we must identify the most cost-effective, efficacious, and safe treatment for each patient. The goal of this article is to aid the practicing vascular specialist consider the optimal choices for the management of patients with vascular disease.

Prevalence of Tibial Artery and Pedal Arch Patency by Angiography in Patients With Critical Limb Ischemia and Noncompressible Ankle Brachial Index

Background—

Approximately 20% of patients undergoing ankle brachial index testing for critical limb ischemia have noncompressible vessels because of tibial artery calcification. This represents a clinical challenge in determining tibial artery patency. We sought to identify the prevalence of tibial artery and pedal arch patency by angiography in these patients.

Methods and Results—

One hundred twenty-five limbs (of 89 patients) with critical limb ischemia and ankle brachial index ≥1.4 who underwent lower extremity angiograms within 1 year were included. Reviewers of angiography were blinded to results of physiological testing. Tibial artery vessels were classified as completely occluded, significantly stenosed (≥50%), or patent (<50% stenosis). The sensitivity of toe brachial index and pulse volume recording to predict tibial artery disease was also determined. Of 125 limbs with noncompressible ankle brachial index, 72 (57.6%) anterior tibial and 80 (64%) posterior tibial arteries were occluded. Another 23 (18.4%) anterior tibial and 13 (10.4%) posterior tibial arteries had ≥50% stenosis. Pulse volume recording was moderate to severely dampened in 54 of 119 (45.4%) limbs. Toe brachial index <0.7 was found in 75 of 83 (90.4%) limbs. Moderate to severe pulse volume recording dampening was 43.6% sensitive, whereas toe brachial index <0.7 was 89.7% sensitive in diagnosing occluded or significantly stenotic tibial artery disease. The pedal arch was absent or incomplete in 86 of 103 (83.5%) limbs.

Conclusions—

Among patients with critical limb ischemia and noncompressible ankle brachial index results, the prevalence of occlusive tibial and pedal arch disease is very high. Toe brachial index <0.7 is more sensitive in diagnosing occluded and significantly stenotic tibial artery disease in these patients compared with ankle pulse volume recording.

Critical Limb Ischemia: An Expert Statement

Critical limb ischemia (CLI), the most advanced form of peripheral artery disease, is associated with significant morbidity, mortality, and health care resource utilization. It is also associated with physical, as well as psychosocial, consequences such as amputation and depression. Importantly, after a major amputation, patients are at heightened risk of amputation on the contralateral leg. However, despite the technological advances to manage CLI with minimally invasive technologies, this condition often remains untreated, with significant disparities in revascularization and amputation rates according to race, socioeconomic status, and geographic region. Care remains disparate across medical specialties in this rapidly evolving field. Many challenges persist, including appropriate reimbursement for treating complex patients with difficult anatomy. This paper provides a comprehensive summary that includes diagnostic assessment and analysis, endovascular versus open surgical treatment, regenerative and adjunctive therapies, and other important aspects of CLI.

Time to Wound Healing and Major Adverse Limb Events in Patients with Critical Limb Ischemia Treated with Endovascular Revascularization

BACKGROUND

There are few studies that quantify the impact of time to wound healing on outcomes after endovascular revascularization of critical limb ischemia (CLI).

METHODS

In this retrospective study, 179 patients with CLI and tissue loss were assessed for adverse events after endovascular therapy. Associations between time to wound healing and outcomes were determined via Cox proportional hazards analysis. The long-term probability of events was assessed with Kaplan-Meier analysis. The primary end point was major adverse limb events (MALE-major amputation, surgical endarterectomy, or bypass). Secondary end points were major amputation, need for repeat endovascular therapy, and mortality.

RESULTS

After multivariable adjustment for time-dependent wound healing, age, renal function, diabetes, and Rutherford class, independent predictors of MALE included the presence of an unhealed wound (hazard ratio [HR], 5.2; 95% confidence interval (CI), 2.3-11.8; P < 0.0001) and creatinine ≥ 2.0 (HR, 2.4; 95% CI, 1.4-4.3; P = 0.003). On Kaplan-Meier analysis, the probability of MALE was greater in patients with unhealed wounds compared with healed wounds (log-rank P < 0.0001). Patients whose wounds healed within 4 months had a lower probability of MALE than patients who did not heal by 4 months (log-rank, P = 0.04). Unhealed wounds were also independently associated with major amputation (HR, 9.0; 95% CI, 2.6-31.1; P = 0.0004), and patients whose wounds healed by 3 months had less major amputation (log-rank, P = 0.04). Unhealed wounds were independently associated with increased risk of mortality (HR, 42.7; 95% CI, 5.7-319.0; P = 0.002) but not repeat revascularization.

CONCLUSIONS

Unhealed wounds are an independent risk factor for MALE, major amputation, and mortality after endovascular treatment of CLI. Wound healing within 3 months is associated with less risk of major amputation, and within 4 months less risk of MALE. A focus should be on achieving wound healing as fast as possible in this population.

Hospital Readmissions Following Endovascular Therapy for Critical Limb Ischemia: Associations With Wound Healing, Major Adverse Limb Events, and Mortality

BACKGROUND

The significance of hospital readmission after endovascular therapy for critical limb ischemia (CLI) is not well established. We sought to investigate the incidence, timing, and causes of readmissions after endovascular therapy for CLI and whether readmission is associated with major adverse limb events (MALE) or mortality.

METHODS AND RESULTS

This was a retrospective study of 252 patients treated with endovascular therapy for CLI. During median follow-up of 381 days (interquartile range [IQR], 115-718), 140 (56%) were readmitted, with median time to readmission of 83 days (IQR, 33-190). Readmission within 30 days occurred in 14% of patients (n=35; 25% of readmissions). Most readmissions occurred between 30 and 180 days (n=67; 48% of readmissions). The most frequent reason for readmission was unhealed wounds (n=63; 45% of readmissions). Independent predictors of readmission by Cox proportional hazards analysis were unhealed wounds, presence of multiple wounds, age ≥70, female sex, hemodialysis, and history of heart failure (P<0.05 for each). By Kaplan-Meier analysis, readmission was greatest in patients with unhealed wounds, followed by patients who never had a wound, and lowest in patients whose wounds completely healed (P<0.0001 overall, and P<0.01 between groups). After multivariable adjustment, readmission remained an independent predictor of composite MALE (major amputation, bypass, or endarterectomy) or mortality (adjusted hazard ratio, 3.1; 95% CI, 1.5-6.5; P=0.002).

CONCLUSIONS

Most readmissions occur 30 and 180 days after endovascular therapy for nonprocedural reasons. Unhealed wounds are an independent risk factor for readmission. Readmission is associated with increased MALE and mortality after endovascular therapy for CLI.

Validation of the relationship between ankle–brachial and toe–brachial indices and infragenicular arterial patency in critical limb ischemia

The relationship between ankle–brachial index (ABI) remains uncertain relative to clinical and angiographic features of critical limb ischemia (CLI). From July 2011 to February 2013, 89 consecutive patients with CLI had non-invasive testing for indications of rest pain ( n=23, 26%), as well as minor ( n=29, 33%) and major ( n=37, 42%) ischemic tissue loss. All patients subsequently underwent ABI testing and lower extremity angiography with visualization of the infragenicular arteries. Toe–brachial index (TBI) testing was available among 31 of these patients. Among patients with any ischemic tissue loss, 29% had an ABI between 0.7 and 1.4. Patients with rest pain alone had reduced odds of abnormal arterial runoff in univariate (OR 0.75, 95% CI 0.63–0.90; p=0.002) but not multivariate ( p=0.50) analysis. Advanced age, increased ABI, reduced creatinine clearance, hyperlipidemia, and prior coronary artery disease were predictive of abnormal infragenicular runoff. Despite limitations in statistical power, median TBI, compared to ABI, tended to increase when infragenicular arterial runoff was preserved. Overall, the association of TBI with abnormal runoff was not significant ( p=0.38). In conclusion, in the evaluation of CLI, nearly one-third of patients with any ischemic tissue loss had a normal or mildly reduced ABI. Assessment of TBI may augment the diagnostic accuracy of ABI in the evaluation of CLI.

The role of the community clinician in early detection, referral and treatment of critical limb ischaemia

Critical limb ischaemia (CLI) is a significant public health issue worldwide, with an ever-growing incidence among people over 65. Awareness of CLI is low, particularly among non-vascular clinicians, leading to underdiagnosis and undertreatment. A diagnosis of CLI is known to have a grave effect on a person's quality of life, with devastating outcomes for both their life and limb, often resulting in uncontrolled pain, amputation or early death from a cardiovascular event. Community nurses and podiatrists are key clinicians who can play a crucial and active role in earlier identification, rapid referral and ongoing non-surgical care for this overlooked population.