Lower extremity computed tomography angiography can help predict technical success of endovascular revascularization in the superficial femoral and popliteal artery

Intravascular Ultrasound during Endovascular Intervention for Peripheral Artery Disease, by Severity, Location, Device, and Procedure

There is limited evidence for the role of intravascular ultrasound (IVUS) in patients who underwent peripheral vascular intervention (PVI). We conducted retrospective cohort study utilizing the Healthcare Cost and Utilization Project-Agency for Healthcare Research and Quality National Readmission database to delineate outcomes in IVUS-guided PVI versus non-IVUS-guided PVI. The present study utilized National Readmission database between January 1, 2016, and December 31, 2019. We identified patients who underwent endovascular intervention for peripheral artery disease using relevant International Classification of Diseases, Tenth Revision, Procedural Coding System. The cohort was divided based on the use of IVUS during the procedure. The primary outcome was major amputation at 6 months after index hospitalization. Measured confounders were matched using propensity score inverse probability of treatment weighing method. We further performed a subgroup analysis based on disease severity, location of intervention, device, and procedure. A total of 434,901 hospitalizations were included in the present analysis. PVI with IVUS compared with no IVUS had similar risk of amputation at 6 months (195 of 8,939 [2.17%] vs 10,404 of 384,003 [2.71%]), hazard ratio 0.98, CI 0.77 to 1.25. Further, there was no difference in the rates of secondary outcomes. On subgroup analysis, amputation rates were significantly lower in patients with rest pain, in iliac intervention, or patients who underwent drug-eluting stent implantation with the use of IVUS compared with no IVUS. This nationwide observational study showed that there was no difference in major amputation rates with the use of IVUS in patients who underwent PVI. However, in subgroup of patients with rest pain, iliac intervention or drug-eluting stent implantation IVUS use was associated with significantly lower major amputation rates.

In vitro and in vivo optimized reconstruction for low-keV virtual monoenergetic photon-counting detector CT angiography of lower legs

BACKGROUND

Lower extremity peripheral artery disease frequently presents with calcifications which reduces the accuracy of computed tomography (CT) angiography, especially below-the-knee. Photon-counting detector (PCD)-CT offers improved spatial resolution and less calcium blooming. We aimed to identify the optimal reconstruction parameters for PCD-CT angiography of the lower legs.

METHODS

Tubes with different diameters (1-5 mm) were filled with different iodine concentrations and scanned in a water container. Images were reconstructed with 0.4 mm isotropic resolution using a quantitative kernel at all available sharpness levels (Qr36 to Qr76) and using different levels of quantum iterative reconstruction (QIR-2-4). Noise and image sharpness were determined for all reconstructions. Additionally, CT angiograms of 20 patients, reconstructed with a medium (Qr44), sharp (Qr60), and ultrasharp (Qr72) kernel at QIR-2-4, were evaluated by three readers assessing noise, delineation of plaques and vessel walls, and overall quality.

RESULTS

In the phantom study, increased kernel sharpness led to higher image noise (e.g., 16, 38, 77 HU for Qr44, Qr60, Qr72, and QIR-3). Image sharpness increased with increasing kernel sharpness, reaching a plateau at the medium-high level 60. Higher QIR levels decreased image noise (e.g., 51, 38, 25 HU at QIR-2-4 and Qr60) without reducing vessel sharpness. The qualitative in vivo results confirmed these findings: the sharp kernel (Qr60) with the highest QIR yielded the best overall quality.

CONCLUSION

The combination of a sharpness level optimized reconstruction kernel (Qr60) and the highest QIR level yield the best image quality for PCD-CT angiography of the lower legs when reconstructed at 0.4-mm resolution.

RELEVANCE STATEMENT

Using high-resolution PCD-CT angiography with optimized reconstruction parameters might improve diagnostic accuracy and confidence in peripheral artery disease of the lower legs.

KEY POINTS

Effective exploitation of the potential of PCD-CT angiography requires optimized reconstruction parameters. Too soft or too sharp reconstruction kernels reduce image quality. The highest level of quantum iterative reconstruction provides the best image quality.

The Clinical Utility of Lower Extremity Dual-Energy CT Angiography in the Detection of Bone Marrow Edema in Diabetic Patients with Peripheral Artery Disease

(1) Background: Type 2 diabetes is a major cause of incidences and the progression of peripheral artery disease (PAD). Bone marrow edema (BME) is an important finding suggestive of underlying bone inflammation in non-traumatic diabetic patients with PAD. Our aim was to evaluate the presence, severity, and clinical implications of BME detected by virtual non-calcium application (VNCa) of dual-energy CT angiography (DE-CTA). (2) Methods: A consecutive series of 76 diabetic patients (55 men; mean age 71.6 ± 11.2 yrs) submitted to lower limb DE-CTA for PAD evaluation and revascularization planning, which were retrospectively analyzed. VNCa images were independently and blindly revised for the presence, location, and severity of BME by two radiologists with 10 years of experience. BME and non-BME groups were evaluated in terms of PAD clinical severity and 6-month secondary major amputation rate. (3) Results: BME was present in 17 (22%) cases, while 59 (78%) patients were non-BME. The BME group showed a significantly higher incidence of major amputation (p < 0.001) and a significantly higher number of patients with advanced clinical stages of PAD compared to the non-BME group (p = 0.024). (4) Conclusions: Lower limb DE-CTA with VNCa application is a useful tool in the detection of BME in diabetic patients with PAD, simultaneously enabling the evaluation of the severity and location of the arterial disease for revascularization planning. BME presence could be a marker of clinically severe PAD and a possible risk factor for revascularization failure.

Revascularization Outcomes Stratified by Glycemic Control in Patients with Diabetes Mellitus and Chronic Limb-Threatening Ischemia

BACKGROUND

The prevalence of chronic limb-threatening ischemia (CLTI) has increased alongside rising rates of diabetes mellitus (DM). While diabetic patients with CLTI have worse outcomes compared to patients without diabetes, conflicting data exist on the relationship between the severity of DM and CLTI outcomes. Close inspection of the relationship between DM severity and outcomes in CLTI may benefit surgical decision-making and patient education.

METHODS

We retrospectively reviewed patients who received endovascular intervention or surgical bypass for CLTI at our multidisciplinary Limb Preservation Program from 2013 to 2019 to collect patient characteristics using Society for Vascular Surgery (SVS) reporting standards, arterial lesion characteristics from recorded angiograms, and outcomes, including survival, amputation, wound healing, and revascularization patency. Controlled DM was defined as SVS Grade 1 (controlled, not requiring insulin) and Grade 2 (controlled, requiring insulin), while uncontrolled DM was defined as SVS Grade 3 (uncontrolled), and DM severity was assessed using preoperative hemoglobin A1c (HgbA1c) values. Product-limit Kaplan-Meier was used to estimate survival functions. Univariable Cox proportional hazards analyses guided variable selection for multivariable analyses.

RESULTS

Our Limb Preservation Program treated 177 limbs from 141 patients with DM. Patients with uncontrolled DM were younger (60.44 ± 10.67 vs. 65.93 ± 10.89 years old, P = 0.0009) and had higher HgbA1c values (8.97 ± 1.85% vs. 6.79 ± 1.10%, P < 0.0001). Fewer patients with uncontrolled DM were on dialysis compared to patients with controlled DM (15.6% vs. 30.9%, P = 0.0278). By Kaplan-Meier analysis, DM control did not affect time to mortality, limb salvage, wound healing, or loss of patency. However, multivariable proportional hazards analysis demonstrated increased risk of limb loss in patients with increasing HgbA1C (hazard ratio (HR) = 1.96 [1.42-2.80], P < 0.0001) or dialysis dependence (HR = 15.37 [3.44-68.73], P = 0.0003), increased risk of death in patients with worsening pulmonary status (HR = 1.70 [1.20-2.39], P = 0.0026), and increased risk of delayed wound healing in patients who are male (HR = 0.48 [0.29-0.79], P = 0.0495). No independent association existed between loss of patency with any of the variables we collected.

CONCLUSIONS

Patients with uncontrolled DM, as defined by SVS reporting standards, do not have worse outcomes following revascularization for CLTI compared to patients with controlled DM. However, increasing HgbA1c is associated with a greater risk for early amputation. Before revascularization, specific attention to the level of glycemic control in patients with DM is important, even if DM is "controlled." In addition to aggressive attempts at improved glycemic control, those with elevated HgbA1c should receive careful education regarding their increased risk of amputation despite revascularization. Future work is necessary to incorporate the severity of DM into risk models of revascularization for the CLTI population.

Predictors of Crossing Failure in Femoropopliteal Lesions: The Importance of Length of the Lesion and Calcification

BACKGROUND

Endovascular therapy is nowadays the first choice for most patients with peripheral artery disease. The most important cause of technical failure is failure to cross the lesion with a wire. In this retrospective study, we explore possible risk factors of crossing failure.

METHODS

We included all consecutive patients in whom the lesion could not be crossed in the period of the January 1, 2017-January 1, 2022. The lesions of these patients were compared with patients in whom the lesion could be crossed (2:1). The following potential anatomical risk factors were compared: location of the lesion, occlusion length, lesion length, Peripheral Arterial Calcium Scoring Scale, Peripheral Academic Research Consortium, circumferential characterization classification, and the Trans-Atlantic Inter-Society Consensus II classification.

RESULTS

In 71 patients, the lesion could not be crossed; these patients were compared with 142 patients. There were significantly more patients with hypertension and hyperlipidemia in the group with crossing failure. The following factors were risk factors for crossing failure: occlusion length, lesion length, Peripheral Arterial Calcium Scoring Scale, Peripheral Academic Research Consortium, and circumferential characterization classification.

CONCLUSIONS

Although conclusions should be carefully drawn from this retrospective study, calcification and length of the lesion are associated with crossing failure in the femoropopliteal segment. The Trans-Atlantic Inter-Society Consensus II classification was the best predictor of crossing failure.

Influence of Perioperative Factors on Patency After Endovascular and Hybrid Treatments of TASC II D Aortoiliac Occlusive Lesions

BACKGROUND

Treatment of Trans-Atlantic Inter-Society Consensus (TASC) II D aortoiliac occlusive disease (AIOD D) remains a controversial topic. Although current recommendations support conventional surgical treatment, several recent studies have reported promising results with endovascular and hybrid strategies. The purpose of this work was to describe the outcomes of endovascular and hybrid management of AIOD D and to investigate the influence of perioperative factors on patency.

METHODS

This was a retrospective single-center study covering the period from 2016 to 2021. The primary end point was primary patency at 12 months. Secondary endpoints included technical success rate, 30-day mortality, early major complication rate, primary assisted and secondary patency at 12 months, and primary patency at 24 months. After descriptive statistical analysis, a survival analysis was conducted using the Kaplan-Meier method. Eighteen perioperative factors potentially associated with primary patency were studied by univariate and multivariate analysis adjusted by a Cox regression model.

RESULTS

In all, 82 patients (112 limbs) had undergone an attempt at endovascular (n = 55, 67%) or hybrid (n = 27, 33%) treatment for AIOD D over the study period. The technical success rate was 99%. The 30-day mortality rate was 3%. The early major complication rate was 11%. The primary patency rates at 12 and 24 months were 87.9% [80.3; 96.3] and 77% [66.3; 89.3], respectively. The primary assisted and secondary patency rates at 12 months were 92.6% [86.3; 99.2] and 96% [91.4; 100]. Among the perioperative factors studied, the heavily calcified nature of the target lesions was the only variable significantly associated with primary patency loss in the multivariate analysis (P = 0.021).

CONCLUSION

Although the results of endovascular and hybrid treatment of AOID D are acceptable, future studies should focus on improving patency rates in heavily calcified lesions. Specific tools of endovascular preparation (intravascular lithotripsy, atherectomy) may represent interesting ways of research.

High risk and low prevalence diseases: Acute limb ischemia

INTRODUCTION

Acute limb ischemia is a rare but serious condition that carries with it a high rate of morbidity and mortality.

OBJECTIVE

This review highlights the pearls and pitfalls of acute limb ischemia, including presentation, diagnosis, and management in the emergency department (ED) based on current evidence.

DISCUSSION

Acute limb ischemia is defined as a sudden decrease in limb perfusion resulting in cessation of blood flow and nutrient and oxygen delivery to the tissues. This leads to cellular injury and necrosis, ultimately resulting in limb loss and potentially systemic symptoms with significant morbidity and mortality. There are several etiologies including native arterial thrombosis, arterial thrombosis after an intervention, arterial embolus, and arterial injury. Patients with acute limb ischemia most commonly present with severe pain and sensory changes in the initial stages, with prolonged ischemia resulting in weakness, sensory loss, and color changes to the affected limb. The emergency clinician should consult the vascular specialist as soon as ischemia is suspected, as the diagnosis should be based on the history and examination. Computed tomography angiography is the first line imaging modality, as it provides valuable information concerning the vasculature and surrounding tissues. Doppler ultrasound of the distal pulses may also be obtained to evaluate for arterial and venous flow. Once identified, management includes intravenous unfractionated heparin and vascular specialist consultation for revascularization.

CONCLUSIONS

An understanding of acute limb ischemia can assist emergency clinicians in diagnosing and managing this potentially deadly disease.

Peripheral arterial disease treatment planning using noninvasive and invasive imaging methods

With the growing prevalence and mortality of peripheral arterial disease, preoperative assessment, risk stratification, and determining the correct indication for endovascular and open surgical procedures are essential for therapeutic decision-making. The effectiveness of interventional procedures is significantly influenced by the plaque composition and calcification pattern. Therefore, the identification of patients for whom endovascular treatment is the most appropriate therapeutic solution often remains a challenge. The most commonly used imaging techniques have their own limitations and do not provide findings detailed enough for specific, personalized treatment planning. Using state-of-the-art noninvasive and invasive imaging modalities, it is now possible to obtain a view, not only of the complex vascular anatomy and plaque burden of the lower extremity arterial system, but also of complex plaque structures and various pathologic calcium distribution patterns. In the future, as these latest advancements in diagnostic methods become more widespread, we will be able to obtain more accurate views of the plaque structure and anatomic complexity to guide optimal treatment planning and device selection. We reviewed the implications of the most recent invasive and noninvasive lower extremity imaging techniques and future directions.

Lower limb arterial calcification and its clinical relevance with peripheral arterial disease

Lower limb arterial calcification (LLAC) is associated with an increased risk of mortality and it predicts poor outcomes after endovascular interventions in patients with peripheral artery disease (PAD). Detailed histological analysis of human lower artery specimens pinpointed the presence of LLAC in two distinct layers: the intima and the media. Intimal calcification has been assumed to be an atherosclerotic pathology and it is associated with smoking and obesity. It becomes instrumental in lumen stenosis, thereby playing a crucial role in disease progression. On the contrary, medial calcification is a separate process, systematically regulated and linked with age advancement, diabetes, and chronic kidney disease. It prominently interacts with vasodilation and arterial stiffness. Given that both types of calcifications frequently co-exist in PAD patients, it is vital to understand their respective mechanisms within the context of PAD. Calcification can be easily identifiable entity on imaging scans. Considering the highly improved abilities of novel imaging technologies in differentiating intimal and medial calcification within the lower limb arteries, this review aimed to describe the distinct histological and imaging features of the two types of LLAC. Additionally, it aims to provide in-depth insight into the risk factors, the effects on hemodynamics, and the clinical implications of LLAC, either occurring in the intimal or medial layers.

Impact of "black rock" on clinical outcomes after endovascular therapy for de novo calcified femoropopliteal lesions

The relationship between severity of calcification and clinical outcomes after endovascular therapy (EVT) for femoropopliteal lesions is well known. We often encounter dense calcifications in our daily practice, which are darker than normal calcifications on angiography. Accordingly, we named it "black rock" (BR), and investigated its impact on clinical outcomes after EVT. We retrospectively analyzed 677 lesions in 495 patients who underwent EVT for de novo calcified femoropopliteal lesions at our hospital between April 2007 and June 2020. BR is defined as a calcification which is 1 cm or more in length, occupies more than half of the vessel diameter, and appears darker than the body of the femur on angiography. Propensity score matching analysis was performed to compare clinical outcomes between lesions with BR [BR (+) group] and without BR [BR (-) group]. A total of 119 matched pairs of lesions were analyzed. Primary patency at 2 years was significantly lower in the BR (+) group than in the BR (-) group (48% vs. 75%, p = .0007). Multivariate analysis revealed that the presence of BR [hazard ratio (HR) = 2.23, 95% confidence interval (CI); 1.48-3.38, p = .0001], lesion length (HR = 1.03, 95%CI; 1.00-1.06, p = .0244), and no scaffold use (HR = 1.58, 95%CI; 1.06-2.36, p = .0246) were predictors of restenosis. The presence of BR is independently associated with clinical outcomes after EVT for de novo calcified femoropopliteal lesions.

The natural history of chronic limb-threatening ischemia after technical failure of endovascular intervention

OBJECTIVES

The treatment for chronic limb-threatening ischemia (CLTI) has changed dramatically in the last few decades with a shift toward an endovascular-first approach and aggressive revascularization to achieve limb salvage. As the size of the CLTI population and intervention rates increase, patients will continue to experience technical failure (TF). Here, we describe the natural history of patients after TF of endovascular intervention for CLTI.

METHODS

We conducted a retrospective cohort study of patients with CLTI who attempted endovascular intervention or bypass at our multidisciplinary limb salvage center from 2013 to 2019. Patient characteristics were collected according to the Society for Vascular Surgery's reporting standards. Primary outcomes included survival, limb salvage, wound healing, and revascularization patency. Product-limit Kaplan-Meier estimated survival functions for these outcomes, and between-group comparisons were made using Mantel-Cox log-rank nonparametric tests.

RESULTS

We identified 242 limbs from 220 unique patients who underwent primary bypass (n = 30) or attempted endovascular intervention (n = 212) at our limb salvage center. Endovascular intervention was a TF in 31 (14.6%) limbs. After TF, 13 limbs underwent secondary bypass and 18 limbs were managed medically. Patients who experienced TF tended to be older (P < .001), male (P = .003), current tobacco users (P = .014), have longer lesions (P = .001), and have chronic total occlusions of target arteries (P < .001) as compared with those who experienced technical success. Furthermore, the TF group had worse limb salvage (P = .047) and slower wound healing (P = .028), but their survival was not different. Survival, limb salvage, and wound healing were not different in patients who received secondary bypass or medical management after TF. The secondary bypass group was older (P = .012) and had a lower prevalence of tibial disease (P = .049) than the primary bypass group and trended toward decreased survival, limb salvage, and wound healing (P = .059, P = .083, and P = .051, respectively).

CONCLUSIONS

Increased age, male sex, current tobacco use, longer arterial lesions, and occluded target arteries are associated with TF of endovascular intervention. Limb salvage and wound healing are relatively poor after TF of endovascular intervention, but survival appears comparable with patients who experience technical success. Secondary bypass may not always rescue patients after TF, though our sample size limits statistical power. Interestingly, patients who received a secondary bypass after TF trended toward decreased survival, limb salvage, and wound healing compared with primary bypass.

Utility and safety of a novel method using a Wingman catheter for patients with lower extremity arterial disease complicated with severely calcified lesions: Wingman's bevel tip inner catheter removal technique-A prospective cohort study

Background and Aims

In cases of lower extremity artery disease (LEAD) accompanied by heavily calcified lesions, endovascular treatment becomes necessary at times. To effectively address these challenging calcified lesions, we developed an innovative approach named WINNER (Wingman's bevel tip inner catheter removal) technique. This study investigated the effectiveness and safety of a novel method using the WINNER technique.

Methods

This was a two-center, prospective observational study. We analyzed the clinical data of patients with LEAD complicated with severely calcified lesions who underwent the WINNER technique between January 2021 and December 2022. We investigated the patients' characteristics, target lesions, and intervention results in terms of crossing device rates and periprocedural complications.

Results

A total of 35 patients were treated using the WINNER technique for LEAD complicated by severely calcified lesions. Key patient characteristics were a mean age of 75 ± 9 years, 83% male, 71% hemodialysis, 60% chronic limb-threatening ischemia, and mean lesion length of 147 ± 88 mm. Using the WINNER technique, a device crossing was achieved in 34 patients (97.1%). Wire perforation occurred in one patient, and WINNER catheter rupture occurred in three patients.

Conclusions

The WINNER technique is useful for treating severely calcified lesions, and we should consider using this technique to cross devices for lesions with severe calcifications.

The Role of Imaging in Peripheral Interventions

Patient evaluation is critical to identify and quantitate patient's disease. Aside from the patient's history and physical examination, imaging can help confirm and determine the extent of disease. Imaging can aid in treatment planning once the decision to proceed to intervention has been made. This chapter will discuss the role of imaging before and after peripheral arterial interventions and how it may improve intervention outcomes. It will discuss the value of the arterial noninvasive examinations (ankle-brachial index, toe-brachial index, pulse volume recordings, and arterial duplex ultrasound), computed tomographic angiograms, magnetic resonance angiogram, and intravascular ultrasound.

The posterior tibial artery free flap for head and neck reconstruction

PURPOSE

The posterior tibial artery free flap (PTAFF) has been a mainstay of lower extremity reconstruction. Over the past 30 years, it has been intermittently used for head and neck reconstruction with recent renewed interest given its versatility.

RECENT FINDINGS

Use of the PTAFF in head and neck reconstruction is expanding along with the continued evolution of microvascular techniques. Differences in overall health, incidence of smoking, and body habitus can impact the utility of this flap and should be taken into consideration when choosing to use it.

SUMMARY

The PTAFF for head and neck reconstruction is a useful tool for the head and neck/reconstructive surgeon. Understanding the potential pitfalls and caveats to use of the PTAFF is important for successful use of this versatile flap.

Explore the Value of Dual Source Computer Tomography Automatic Tube Current Regulation in Reducing the Radiation Dose of CTA in Lower Extremity Vessels

Objective

To investigate the value of dual source computer tomography automatic tube current regulation in reducing the radiation dose of CTA in lower limb vessels.

Methods

From February 2020 to December 2021, 64 patients with lower limb artery CTA were selected in our hospital because of the symptoms of foot ischemia. According to the random number table, patients were divided into control group (treated with fixed tube current technology) and observation group (treated with automatic tube current regulation technology), with 32 cases in each group. All patients underwent a dual source computer tomography scan. Control group: tube voltage 120 kV, tube current 250 mA; Observation group: tube voltage was 80 kV, and reference tube current was 80–380 mA. Other scanning conditions of patients in the two groups were the same. CTDIvol, DLP and calculated SNR and CNR were recorded to obtain the ED.

Results

The values of CTDIvol, DLP and ED in the observation group were lower than those in the control group (P < 0.05). There was no significant difference in CT value, SD value, SNR value and CNR value of the femoral artery segment, popliteal artery segment and posterior tibial artery segment between the two groups (P > 0.05). The image quality scores of patients in the control group were slightly higher than those in the observation group, but there was no statistical difference between the two groups (P > 0.05).

Conclusion

The application of dual source computer tomography automatic tube current adjustment technology in CTA examination of lower limb vessels can automatically adjust the compensation output and realize the output of different tube currents in different thicknesses, densities and angles. On the premise of not affecting the image quality, the radiation dose in the scanning process to the maximum extent, and reasonably protect the examined patients.

The impact of the field of view (FOV) on image quality in MDCT angiography of the lower extremities

Objectives

To evaluate the impact of the reconstructed field-of-view (FOV) on image quality in computed-tomography angiography (CTA) of the lower extremities.

Methods

A total of 100 CTA examinations of the lower extremities were acquired on a 2 × 192-slice multidetector CT (MDCT) scanner. Three different datasets were reconstructed covering both legs (standard FOV size) as well as each leg separately (reduced FOV size). The subjective image quality was evaluated for the different vessel segments (femoral, popliteal, crural, pedal) by three readers using a semi-quantitative Likert scale. Additionally, objective image quality was assessed using an automated image quality metric on a per-slice basis.

Results

The subjective assessment of the image quality showed an almost perfect interrater agreement. The image quality of the small FOV datasets was rated significantly higher as compared to the large datasets for all patients and vessel segments (p < 0.05) with a tendency towards a higher effect in smaller vessels. The difference of the mean scores between the group with the large FOV and small FOV was 0.68 for the femoral level, 0.83 for the popliteal level, 1.12 for the crural level, and 1.08 for the pedal level. The objective image quality metric also demonstrated a significant improvement of image quality in the small FOV datasets.

Conclusions

Side-separated reconstruction of each leg in CTA of the lower extremities using a small reconstruction FOV significantly improves image quality as compared to a standard reconstruction with a large FOV covering both legs.

Key Points

• In CT angiography of the lower legs, the side-separated reconstruction of each leg using a small field-of-views improves image quality as compared to a standard reconstruction covering both legs.

• The side-separated reconstruction can be readily implemented at every commercially available CT scanner.

• There is no need for additional hardware or software and no additional burden to the patient.

Calcium Score Predicts Mortality After Revascularization in Critical Limb Ischemia

PURPOSE

The calcium score is a measure of vessel wall calcification and has clinical applications when studied in different vascular beds. The presence of vascular calcification in the arteries of the lower limbs is very common in patients with peripheral arterial disease; however, its relationship with the postoperative outcomes in patients undergoing lower limb revascularization is still poorly studied. The aim of this study is to evaluate association between the calcium score of lower limbs and the postoperative outcomes in patients with peripheral arterial disease undergoing revascularization procedures.

METHODOLOGY

We retrospectively analyzed 88 lower limb revascularization procedures in 72 patients with critical limb ischemia who had enhanced computed tomography for preoperative evaluation. The calcium score was calculated, from the angiographic phase of preoperative computed tomography, in the segments of the aorta, iliac, femoropopliteal, and infrapopliteal. It was also calculated the calcium score of the operated limb, and the total calcium score using a standardized method. The outcomes evaluated were the occurrence of acute myocardial infarction, amputation, patency, technical success, and death from any cause. Patients were followed up through a 12 month period.

RESULTS

Among the 88 procedures performed, 31 (43.1%) lesions were classified as Trans-Atlantic Inter-Society Consensus Document II D. There were 66 (75%) endovascular procedures, 16 (18.2%) open surgery, and 6 (6.8%) hybrid interventions. No statistically significant relationship was found between the calcium score of the segments (aorta, iliac, femoropopliteal, infrapopliteal, the operated limb, and total calcium score) and the outcomes of acute myocardial infarction, amputation, patency, and technical success in any of the periods analyzed. The calcium score of the operated limb was higher in patients who died within 30 days and 6 months (6571 vs 2590.6; p=0.026) and (5227.8 vs 2335.3; p=0.036).

CONCLUSION

A standardized calcium score calculation method with the angiographic phase of the computed tomography is feasible and reproducible. Higher values of the calcifications of the operated limb are related to a greater chance of death in the postoperative period. The calcium score of the operated limb can be considered as a marker of clinical severity and prognosis in this group of patients.

Performance of Computed Tomography Angiography Before Revascularization Is Associated With Higher Amputation-Free Survival in Rutherford IIb Acute Lower Limb Ischaemia

Background: Acute lower limb ischemia with a motor deficit (Rutherford IIb) needs urgent revascularization to avoid major amputation and mortality. It is unclear whether immediate revascularization without performing CT angiography (CTA) prior to revascularization in Rutherford IIb acute lower limb ischemia (ALI) is associated with better outcomes. Methods: Retrospective observational study of Rutherford IIb ALI patients treated between 2006 and 2018. A propensity score adjusted analysis was performed to compare outcomes after the performance of CTA examination or not. Results: Among 681 patients, 260 had Rutherford IIb ALI. CTA prior to revascularization was performed in 131 (50.4%) and increased (p < 0.001) throughout the study period. Open vascular and endovascular surgery was first performed in 147 (56.5%) and 113 (43.5%) patients, respectively. The proportion of endovascular treatment increased while the open vascular surgery decreased during the study period (p = 0.031). In the propensity score adjusted analysis, the performance of CTA was associated with decreased risk of combined major amputation /mortality (odds ratio 0.52, 95% confidence interval 0.27-0.99; p = 0.046) at 1 year. Conclusion: Performance of CTA was associated with a higher amputation-free survival in revascularized patients with Rutherford IIb ALI. CTA seem to provide guidance in selecting the most appropriate candidates for revascularization and choice of technique.

Quiescent-Interval Slice-Selective MRA Accurately Estimates Intravascular Stent Dimensions Prior to Intervention in Patients With Peripheral Artery Disease

BACKGROUND

Quiescent-interval slice-selective (QISS) magnetic resonance angiography (MRA) is a non-contrast alternative for the pre-procedural assessment of patients with peripheral artery disease (PAD). However, the feasibility of pre-procedural stent size estimation using QISS MRA would merit investigation.

PURPOSE

To evaluate the feasibility of QISS MRA for pre-procedural stent size estimation in PAD patients compared to computed tomography angiography (CTA).

STUDY TYPE

Retrospective.

SUBJECTS

Thirty-three PAD patients (68 ± 9 years, 18 men, 15 women).

FIELD STRENGTH/SEQUENCE

Two-dimensional balanced steady-state free precession QISS MRA at 1.5 T and 3 T.

ASSESSMENT

All patients received QISS MRA and CTA of the lower extremity run-off followed by interventional digital subtraction angiography (DSA). Stenotic lesion length and diameter were quantified (AMF and AVS with 3 and 13 years of experience in cardiovascular imaging, respectively) to estimate the dimensions of the stent necessary to restore blood flow in the treated arteries. Measured dimensions were adjusted to the closest stent size available.

STATISTICAL TESTS

The Friedman test with subsequent pairwise Wilcoxon signed-rank test was used to compare the estimated stent dimensions between QISS MRA, CTA, and the physical stent size used for intervention. Intra-class correlation (ICC) analysis was performed to assess inter-reader agreement. Significant differences were considered at P < 0.05.

RESULTS

No significant difference was observed between estimated stent diameter by QISS MRA or CTA compared to physical stent diameter (8.9 ± 2.9 mm, 8.8 ± 3.0 mm, and 8.8 ± 3.8 mm, respectively; χ²  = 1.45, P = 0.483). There was a significant underestimation of stent length for both QISS MRA and CTA, compared to physical stent length (45.8 ± 27.8 mm, 46.4 ± 29.3 mm, and 50.4 ± 34.0 mm, respectively; χ²  = 11.96) which could be corrected when measurements were adjusted to the next available stent length (χ²  = 2.38, P = 0.303). Inter-reader assessment showed good to excellent agreement between the readers (all ICC ≥0.81).

DATA CONCLUSION

QISS MRA represents a reliable method for pre-procedural lesion assessment and stent diameter and length estimation in PAD patients.

LEVEL OF EVIDENCE

3 TECHNICAL EFFICACY: Stage 2.

Lower extremity CT angiography in peripheral arterial disease: from the established approach to evolving technical developments

With the advent of multidetector computed tomography (CT), CT angiography (CTA) has gained widespread popularity for noninvasive imaging of the arterial vasculature. Peripheral extremity CTA can nowadays be performed rapidly with high spatial resolution and a decreased amount of both intravenous contrast and radiation exposure. In patients with peripheral artery disease (PAD), this technique can be used to delineate the bilateral lower extremity arterial tree and to determine the amount of atherosclerotic disease while differentiating between acute and chronic changes. This article provides an overview of several imaging techniques for PAD, specifically discusses the use of peripheral extremity CTA in patients with PAD, clinical indications, established technical considerations and novel technical developments, and the effect of postprocessing imaging techniques and structured reporting.

A systematic review and meta-analysis of endovascular angiosomal revascularization in the setting of collateral vessels

OBJECTIVE

Endovascular procedures for targeted treatment of lower extremity wounds can be subdivided as direct revascularization (DR), indirect revascularization (IR), and IR via collateral flow (IRc). Although previous systematic reviews assert superiority of DR when compared with IR, the role of collateral vessels in clinical outcomes remains to be defined. This systematic review and meta-analysis aims to define the usefulness of DR, IR, and IRc in treatment of lower extremity wounds with respect to (1) wound healing, (2) major amputation, (3) reintervention, and (4) all-cause mortality.

METHODS

A meta-analysis was performed in accordance with PRISMA guidelines. Ovid MEDLINE was queried for records pertaining to the study question using appropriate Medical Subject Heading terms. Studies were limited to those using DR, IR, or IRc as a primary intervention and reporting information on at least one of the primary outcomes of interest. No limitation was placed on year of publication, country of origin, or study size. Studies were assessed for validity using the Newcastle-Ottawa Scale. Study characteristics and patient demographics were collected. Data representing the primary outcomes-wound healing, major amputation, reintervention, and all-cause mortality-were collected for time points ranging from one month to four years following intervention. A meta-analysis on sample size-weighted data assuming a random effects model was performed to calculate odds ratios (ORs) for the four primary outcomes at various time points.

RESULTS

We identified 21 studies for a total of 4252 limbs (DR, 2231; IR, 1647; IRC, 270). Overall wound healing rates were significantly superior for DR (OR, 2.45; P = .001) and IRc (OR, 8.46; P < .00001) compared with, IR with no significant difference between DR and IRc (OR, 1.25; P = .23). The overall major amputation rates were significantly superior for DR (OR, 0.48; P < .00001) and IRc (OR, 0.44; P = .006) compared with IR, with DR exhibiting significantly improved rates compared with IRc (OR, 0.51; P = .01). The overall mortality rates showed no significant differences between DR (OR, 0.89; P = .37) and IRc (OR, 1.12; P = .78) compared with IR, with no significant difference between DR and IRc (OR, 0.54; P = .18). The overall reintervention rates showed no significant difference between DR and IR (OR, 1.05; P = .81), with no studies reporting reintervention outcomes for IRc.

CONCLUSIONS

Both DR and IRc offer significantly improved wound healing rates and major amputation rates compared with IR when used to treat critical limb ischemia. Although DR should be the preferred method of revascularization, IRc can offer comparable outcomes when DR is not possible. This analysis was limited by a small sample size of IRc limbs, a predominance of retrospective studies, and variability in outcome definitions between studies.

Trans-popliteal hybrid retrograde technique for revascularization of chronic total occlusions of the superficial femoral artery

OBJECTIVES

We present the technical description and preliminary results of a hybrid approach for the treatment of chronic total occlusions of superficial femoral artery in the setting of critical limb-threatening ischemia (CLTI).

METHODS

A retrospective analysis of selected case series was performed. A trans-popliteal hybrid technique was carried out in seven limbs (six patients). Open exposure of above-the-knee popliteal artery was performed over its maximum calcification zone. After retrograde recanalization and graft-stenting of the entire superficial femoral artery, endarterectomy of the popliteal artery was performed for debulking and widening of the distal landing zone of the endoprosthesis. The latter is included in the bovine patch suture to avoid leaving a segment untreated.

RESULTS

Technical success, haemodynamic and clinical improvement were achieved in all procedures. Median length of treated occlusion was 19.8 cm. After a mean follow-up of 12 months (range 6-26 months), the primary patency was 85.7% (only one asymptomatic occlusion occurred). There were no major cardiovascular or limb adverse events. No re-interventions were required.

CONCLUSION

This less-invasive, one-incision technique is safe and effective for the restoration of in-line flow from groin to ankle, currently recommended in CLTI revascularization. It could be especially useful in highly calcified popliteal artery lesions, hostile groins or those at high risk of infection and in cases of vein absence for bypass surgery.

Analysis of Preoperative CT Scan Can Help Predict Technical Failure of Endovascular Treatment of TASC C-D Aortoiliac Chronic Total Occlusions

BACKGROUND AND AIMS

To evaluate if features of occlusion analyzable on preoperative computed tomography scan could predict risks of technical failure or iliac rupture of endovascular treatment of TransAtlantic InterSociety Consensus C-D aortoiliac chronic total occlusion.

METHODS AND RESULTS

All patients treated by endovascular techniques for a TransAtlantic InterSociety Consensus C-D aortoiliac chronic total occlusion between 2009 and 2016 were included (107 patients, 148 iliac arteries). We evaluated the location of the occlusion and the importance of the arterial calcifications. For this factor, patients were divided into 3 groups: the Black occlusion group with mild or no calcifications, the white occlusion group with moderate no protrusive calcifications, and the white protrusive occlusion group with heavy endoluminal calcifications. Technical failure occurred in 11 iliac arteries and peroperative iliac rupture in 6. The location in the external iliac artery is the most significate risk factor of technical failure in univariate (OR = 9.93; P = 0.0012) and multivariate analysis (OR = 15.26; P = 0.0006). The presence of heavy endoluminal calcifications is a further significate risk factor (OR = 13.88; P = 0.0365). Rupture rate was comparable between the 3 groups.

CONCLUSIONS

Preoperative computed tomography scan can predict risk of technical failure but not of iliac rupture.

Tibiopedal and distal femoral retrograde vascular access for challenging chronic total occlusions: predictors for technical success, and complication rates in a large single-center cohort

OBJECTIVE

To evaluate the safety and effectiveness of tibiopedal and distal femoral access for retrograde crossing of chronic total occlusion (CTO) in Rutherford stage III to VI peripheral arterial occlusive disease, and to determine factors that correlate with technical success.

MATERIAL AND METHODS

One hundred seventy-one consecutive patients were included in this retrospective study. Rutherford stages were III, IV, and V/VI in 24%, 8%, and 67% of patients. Inclusion criteria were CTO at the superficial femoral (SFA), popliteal (PA), and/or below-the-knee (BTK) level, and a failed antegrade treatment followed by a distal retrograde approach. The numbers of occluded vascular levels (OVL), lesion length, degree of calcification, technical success rate, complications, and clinical outcome were noted.

RESULTS

OVL were 1 in 72%, 2 in 20%, and 3 in 8% of patients. CTOs were longer than 20 cm in 45.6% of cases and showed severe calcifications in 50.3%. Target vessels for distal access were the distal SFA/PA in 17% and BTK in 83%. The overall technical success rate was 82%. Severe calcification decreased technical success (p = 0.01) despite lesion length and Rutherford stage. Clinical outcome improved in 123/152 patients with a significant increase of the median ABI (N = 158) from 0.53 (interquartile range 0.39 to 0.61) to 0.85 (0.59 to 1.03; p < 0.001). Complications were reported in 7.6% cases with 2.3% related to the distal vascular access.

CONCLUSION

The tibiopedal and distal femoral retrograde access presents a safe and effective treatment option of CTOs at the thigh and/or BTK after a failed antegrade attempt improving clinical outcome. Technical success decreased with lesion's degree of calcification.

KEY POINTS

• Safety and effectiveness of the tibiopedal and distal femoral access for retrograde crossing of chronic total occlusion. • Target lesion's degree of calcification decreases technical success. • Complications related to the distal vascular access were rare.

The risk factors for calcification vary among the different sections of the lower extremity artery in patients with symptomatic peripheral arterial disease

BACKGROUND

Peripheral arterial disease (PAD) is associated with considerable mortality and morbidity worldwide. The present study explored the risk factors for arterial calcification among the different sections of the lower extremity in patients with PAD and analyzed their correlations with the extent of arterial stenosis at the corresponding section.

METHODS

This study enrolled symptomatic PAD patients from our hospital from March 2017 to March 2018. The lower extremity arterial calcification score (LEACS) and lower extremity arterial stenosis index (LEASI), representing the extent of arterial stenosis, were measured on computed tomography (CT) and the correlations between them were analyzed using Spearman's correlation analysis. The relationships between risk factors and calcification were analyzed among the different sections of the lower extremity artery.

RESULTS

In total, 209 patients were included. The LEACSs of the total lower extremity, aortoiliac artery, and femoropopliteal and infrapopliteal arteries were correlated with the LEASI (all P < 0.05), but their correlation was relatively weak in the aortoiliac artery. Univariate analysis showed that hypertension was associated with the total (P = 0.019) and aortoiliac (P = 0.012) LEACSs. Diabetes was related to both femoropopliteal (P = 0.001) and infrapopliteal (P = 0.002) LEACSs. The infrapopliteal LEACS was higher in male patients (P = 0.011). After adjustment for age, the above relationships were maintained among the different sections, but not in the total lower extremity artery.

CONCLUSIONS

The LEACS is associated with the LEASI in all arterial sections, but that of the aortoiliac artery was relatively weak. Different factors have different effects on calcification among the various sections of the lower extremity artery.

A Quantitative Method for Prediction of True Lumen Recanalization in Chronic Total Occlusion of the Superficial Femoral Artery

BACKGROUND

This study aimed to examine a quantitative method for evaluating calcification in failure in recanalization (FR) in endovascular treatment of superficial femoral artery (SFA) chronic total occlusion, and to investigate the possibility of using a formula to predict the incidence of true lumen recanalization (TR) in such cases.

METHODS

Patients who met the inclusion criteria were retrospectively analyzed in our center from January 2012 to September 2017. A Calcification Lesion Analyzing and Scoring System (CLASS) was established to quantify the characteristics of calcification in SFA computed tomography slices, which were ranked as grade 1-4 and class A-E. Corresponding scores were obtained, and the Cumulative Calcification Score (CCS_O) of occlusive SFA was calculated on the basis of CLASS. The factors correlating to FR and the formula for predicting TR were evaluated.

RESULTS

A total of 215 patients were included in this study. There were 150 cases of TR and 65 cases of subintimal recanalization; 12 (5.6%) cases had FR. The maximum CLASS of occlusion was correlated with FR. Not only the formula including Trans-Atlantic Inter-Society Consensus II grade and CCS_O but also the formula including occlusion length and CCS_O predicted the incidence of TR well.

CONCLUSIONS

The degree of the most severe calcification in occlusive lesions clearly affects success in recanalization. Two quantitative formulas that combine occlusion length or Trans-Atlantic Inter-Society Consensus II grade with CCS_O can predict TR in endovascular treatment of SFA lesions with chronic total occlusion.

Changing National Medicare Utilization of Catheter, Computed Tomography, and Magnetic Resonance Extremity Angiography: A Specialty-focused 16-Year Analysis

To assess changing utilization of extremity angiography from 2001 to 2016, focusing on modalities and provider specialties. Medicare PSPS Master Files from 2001-2016 and POSPUF from 2016 were used to determine overall and specialty utilization of diagnostic catheter angiography (DCA), CT angiography (CTA), and MR angiography (MRA). From 2001 to 2016, extremity angiography increased from 1107 to 1590 extremities imaged per 100,000 beneficiaries, with rapid expansion of CTA (22 in 2001 to 619 in 2009; plateau of 645 in 2016), but declines in DCA (1039 to 914) and MRA (45 to 30). Over time, extremity angiography shifted from 94% DCA, 4% MRA, and 2% CTA to 58% DCA, 41% CTA, and 2% MRA. For radiologists, extremity angiography increased slightly (741 to 767) with increases in CTA (20 to 595) and large decreases in DCA (681 to 145), with MRA remaining low (40 to 27). Extremity angiography increased for cardiologists (197 to 349) and vascular surgeons (87 to 351), both overwhelmingly performing DCA. Radiologists' share of all extremity angiography shifted from 67% to 48%, with interventionalists (47%), generalists (43%), and abdominal radiologists (7.4%) providing most radiologist services in 2016. Throughout, radiologists were the dominant providers of CTA (89% to 92%) and MRA (89% to 90%). Extremity angiography utilization in Medicare beneficiaries increased nearly 50% from 2001 to 2016, largely related to CTA performed by radiologists. Of radiologists, interventionalists and generalists together render most services. Cardiologists and surgeons assumed a large share of DCA previously performed by radiologists.

Preprocedural Cross-Sectional Imaging Prior to Percutaneous Peripheral Arterial Disease Interventions

Preprocedural cross-sectional imaging (PCSI) for peripheral artery disease (PAD) may vary due to patient complexity, anatomical disease burden, and physician preference. The objective of this study was to determine the utility of PCSI prior to percutaneous vascular interventions (PVIs) for PAD. Patients receiving first time lower extremity angiograms from 2013 to 2015 at a single institution were evaluated for PCSI performed within 180 days, defined as computed tomography angiography (CTA) or magnetic resonance angiography (MRA) evaluating abdominal to pedal vasculature. The primary outcome was technical success defined as improving the target outflow vessels to <30% stenosis. Of the 346 patients who underwent lower extremity angiograms, 158 (45.7%) patients had PCSI, including 150 patients had CTA and 8 patients had MRA. Of these, 48% were ordered by the referring provider (84% at an outside institution). Preprocedural cross-sectional imaging was performed at a median of 26 days (interquartile range: 9-53) prior to the procedure. The analysis of the institution's 5 vascular surgeons identified PCSI rates ranging from 31% to 70%. On multivariate analysis, chronic kidney disease (odds ratio [OR] = 0.35; 95% confidence interval [CI]: 0.17-0.73) was associated with less PSCI usage, and inpatient/emergency department evaluation (OR = 3.20; 95% CI: 1.58-6.50) and aortoiliac disease (OR = 2.78; 95% CI: 1.46-5.29) were associated with higher usage. After excluding 31 diagnostic procedures, technical success was not statistically significant with PSCI (91.3%) compared to without PCSI (85.6%), P = .11. When analyzing 89 femoral-popliteal occlusions, technical success was higher with PCSI (88%) compared to procedures without (69%) P = .026. Our analysis demonstrates that routine ordering of PCSI may not be warranted when considering technical success of PVI; however, PCSI may be helpful in treatment planning. Further studies are needed to confirm these findings in another practice setting, with more prescriptive use of PCSI to improve procedural success, and thereby improve the value of PCSI.

Lower Limb Arterial Calcification and Acute Thrombosis Risk in Patients with Peripheral Artery Disease

BACKGROUND

Calcification is closely related to in situ thrombosis secondary to plaque rupture in the coronary artery. However, the association between calcification in lower extremity arteries and acute thrombosis has not been assessed. We thus sought to determine whether lower limb arterial calcification (LLAC) was correlated with acute thrombosis in patients with symptomatic peripheral artery disease (PAD).

METHODS

We retrospectively reviewed consecutive patients presenting with symptomatic PAD between April 2017 and March 2018 who underwent lower extremity arterial evaluation by computed tomography (CT) angiography. Patient characteristics and cardiovascular risk factors were recorded, and LLAC scores were determined by noncontrast CT scans. Univariate and multivariate logistic regression was used to identify factors associated with acute thrombosis.

RESULTS

The record search identified 201 patients with symptomatic PAD, including 24 with acute thrombosis and 177 without. Patients in the acute thrombosis group were significantly younger (P = 0.04) and had less diabetes mellitus (P = 0.04). Patients with acute thrombosis had more advanced ischemia at presentation (P < 0.01) and higher amputation rate within 30 days (P < 0.01). Univariate regression showed a significant association among acute thrombosis and age, diabetes mellitus, and LLAC score; in multivariable analysis, only the LLAC score (odds ratio 0.60, 95% confidence interval 0.37-0.98) maintained an association with acute thrombosis after adjusting for relevant risk factors.

CONCLUSIONS

The LLAC score is independently and inversely associated with acute thrombosis in patients with PAD.