Significance of the Early Postoperative Duplex Result in Infrainguinal Vein Bypass Surveillance

A Rare Presentation of Pseudoaneurysm of the Popliteal Artery After Total Knee Replacement: A Case Report and Review of the Literature

Total knee replacement (TKR) is a common successful surgery in terms of the outcomes. The common complications of TKR are joint infection, deep venous thrombosis (DVT), wound complication, and postoperative knee instability. Arterial complications are not common. We are presenting a 61-year-old man who underwent left TKR. Upon postoperative regular follow-up, the patient developed symptoms and clinical presentation for DVT. However, initial duplex ultrasonography was negative for DVT. Repeated duplex ultrasonography showed a pseudoaneurysm of the popliteal artery, and the diagnosis was confirmed with computed tomography (CT) angiography. Pseudoaneurysm of the popliteal artery is a rare complication following primary TKR. Our patient underwent endovascular angioplasty and stenting of the pseudoaneurysm of the left popliteal artery. The patient completed three years and six months of follow-up with an uneventful course. We selected to share our experience of this rare case because pseudoaneurysm of the popliteal artery is a rare complication after TKR, which is usually present with symptoms that can mimic DVT, such as acute lower limb swelling, calf muscle pain, and pain with passive ankle dorsiflexion. Duplex ultrasonography is the preferred first diagnostic tool, and CT angiography (CTA) is needed to confirm the diagnosis and to plan treatment. Treatment with endovascular stent proved to be safe and successful with no infection risk or need for modifying rehabilitation protocol after more than three years of follow-up.

The Society for Vascular Surgery practice guidelines on follow-up after vascular surgery arterial procedures

Although follow-up after open surgical and endovascular procedures is generally regarded as an important part of the care provided by vascular surgeons, there are no detailed or comprehensive guidelines that specify the optimal approaches with regard to testing methods, indications for reintervention, and follow-up intervals. To provide guidance to the vascular surgeon, the Clinical Practice Council of the Society for Vascular Surgery appointed an expert panel and a methodologist to review the current clinical evidence and to develop recommendations for follow-up after vascular surgery procedures. For those procedures for which high-quality evidence was not available, recommendations were based on observational studies, committee consensus, and indirect evidence. Recognizing that there are numerous published reports on the role of duplex ultrasound for surveillance of infrainguinal vein bypass grafts, the Society commissioned a systematic review and meta-analysis on this topic. The panel classified the strength of each recommendation and the corresponding quality of evidence on the basis of the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) system: recommendations were graded either strong or weak, and the quality of evidence was graded high, moderate, or low. The resulting recommendations represent a wide variety of open surgical and endovascular procedures involving the extracranial carotid artery, thoracic and abdominal aorta, mesenteric and renal arteries, and lower extremity arterial revascularization. The panel also identified many areas in which there was a lack of high-quality evidence to support their recommendations. This suggests that there are opportunities for further clinical research on testing methods, threshold criteria, and the role of surveillance as well as on the modes of failure and indications for reintervention after vascular surgery procedures.

Validation of a Decision Tree to Streamline Infrainguinal Vein Graft Surveillance

BACKGROUND

Duplex ultrasound (DU)-based graft surveillance remains controversial. The aim of this study was to assess the ability of a recently proposed decision tree in identifying high-risk grafts which would benefit from DU-based surveillance.

MATERIALS AND METHODS

Consecutive patients undergoing infrainguinal vein graft bypass from January 2008 to December 2015 were identified from the National Vascular registry and enrolled in a duplex surveillance program. An early postoperative DU was performed at a median of 6 weeks (range: 4-9 weeks). Grafts were classified into high risk or low risk based on the findings of the earliest postoperative scan and 4 established risk factors for graft failure (diabetes, smoking, infragenicular distal anastomosis, and revision bypass surgery) using a classification and regression tree (CRT). The accuracy of the CRT model was evaluated using area under receiver operator characteristic (AROC) curve.

RESULTS

About 278 vein graft bypasses were performed; 29 grafts had occluded by the first surveillance visit; 249 vein grafts were entered into surveillance. Sixty-four (23%) developed critical stenosis. Overall 30-month primary patency, primary-assisted patency, and secondary patency rates were 71.2%, 77.2%, and 80.1%, respectively. AROC for prediction of graft stenosis or occlusion was 83% (95% confidence interval [CI]: 78-87%). The sensitivity and specificity of the CRT model for prediction of graft stenosis or occlusion were 95% (95% CI: 88-98%) and 52.2% (95% CI: 45-60%).

CONCLUSIONS

A prediction model based on commonly recorded clinical variables and early postoperative DU scan is accurate at identifying grafts which are at high risk of failure. These high-risk grafts may benefit from DU-based surveillance.

Development of a Telemetric System for Postoperative Follow-up of Vascular Surgery Procedures: In Vitro Model

Background

Because of the unique electromagnetic characteristics of the magnetoelastic microwire, the changes in the pressure of a fluid will provoke a variation of the mechanical pressure on the sensor, which will cause a variation of its magnetization that will be detectable wirelessly. Thus, a wireless system can be developed for following up vascular surgery procedures.

Methods and Results

The sensor consists of a magnetoelastic microwire ring, which was integrated into an in vitro model with pulsatile flow. Different degrees of stenosis were simulated in different locations both in bovine artery as well as in a polytetrafluoroethylene anastomosis. A Fourier analysis of the registered signals and a statistical analysis using Pearson test and receiver operating characteristic (ROC) curves were made. A Pearson index of 0.945 (P<0.001) was obtained between the invasive pressure of the fluid and the power of the signal transmitted by the sensor in bovine artery. The sensor obtained very good ROC curves upon analyzing the signals registered, both in the case of preanastomotic stenosis (area under the curve [AUC], 0.98; 95% CI, 0.97–1.00), of anastomosis (AUC, 0.93; 95% CI, 0.86–0.99), as well as distal (AUC, 0.88; 95% CI, 0.79–0.98), compared to the control group.

Conclusions

The magnetoelastic microwire has shown that it is capable of detecting, locating, and quantifying the degree of stenosis in bovine artery, as well as in a latero‐terminal anastomosis, with a high statistical potency. For the first time, a wireless in vitro sensor has been developed for the postoperative follow‐up of vascular surgery procedures.

The correlation between computed tomography and duplex evaluation of autogenous vein bypass grafts and their relationship to failure

OBJECTIVE

Duplex ultrasound (DUS) imaging for vein bypass graft (VBG) surveillance is confounded by technical and physiologic factors that reduce the sensitivity for detecting impending graft failure. In contrast, three-dimensional computed tomography angiography (CTA) offers high-fidelity anatomic characterization of VBGs, but its utility in detecting at risk grafts is unknown. The current study analyzed the correlation between DUS and CTA for detection of vein graft stenosis and evaluated the relationship of the observed abnormalities to VBG failure.

METHODS

Consecutive lower extremity VBG patients underwent surveillance with concurrent DUS imaging and CTA at 1 week and at 1, 6, and 12 months postoperatively. A standardized algorithm was used for CT reconstruction and extraction of the lumen geometries at 1-mm intervals. At each interval, CT-derived cross-sectional areas were coregistered and correlated to DUS peak systolic velocities (PSVs) within six predesignated anatomic zones and then analyzed for outcome association. Vein graft failure was defined as pathologic change within a given anatomic zone resulting in thrombosis, amputation, or reintervention within the 6-month period after the observed time point.

RESULTS

The study recruited 54 patients, and 10 (18%) experienced failure ≤18 months of implantation. The expected inverse relationship between cross-sectional area and PSV was only weakly correlated (Spearman rank coefficient = -0.19). Moderate elevations in the PSV ratio (PSVr; 2-3.5) were frequently transient, with 14 of 18 grafts (78%) demonstrating ratio reduction on subsequent imaging. A PSVr ≥3.5 was associated with a 67% failure rate. CT stenosis <50% was highly correlated with success (0 failures); however, high-grade (>80%) CT stenosis was more likely to succeed than to fail (25%). Significant discordance between CT and DUS was found in 18 patients. Although 14 of these patients had CT stenosis >70% with a PSVr <3.5, subsequent failure occurred in only two. Conversely, graft failure occurred in three of four patients with CT stenosis <70% but PSVr >3.5. Focused analysis of these patients using computational fluid dynamic modeling demonstrated that vein side branches, local tortuosity, regional diameter variations, and venovenostomies were the drivers of these discrepancies.

CONCLUSIONS

This analysis demonstrated that a PSVr ≥3.5 is strongly correlated with VBG failure, whereas the natural history of moderately elevated PSVr (2-3.5) is largely clinically benign. Although minimum stenosis on the CT scan was highly predictive of success, high-grade CT stenosis was infrequently associated with failure. The interaction of anatomic features with the local flow dynamics was identified as the primary confounder for a direct correlation between CT and DUS imaging.

Balloon angioplasty for revision of failing lower extremity bypass grafts

OBJECTIVE

The aim of this study was to evaluate the efficacy and safety of balloon angioplasty as the primary method of intervention in patients with color duplex ultrasound documented failing bypass grafts and to determine factors that may affect the patency of lower extremity bypass grafts revised by percutaneous transluminal angioplasty (PTA).

METHODS

All consecutive patients who underwent lower extremity bypass grafts from January 2009 to December 2013 were enrolled in a graft surveillance program. Patients identified as having failing grafts underwent arteriography to confirm the diagnosis with a view to concomitant treatment of the lesion using balloon angioplasty. Procedural success was defined as <30% residual stenosis. Treatment failure was defined as target lesion restenosis or graft occlusion. Descriptive and life-table analyses were performed.

RESULTS

PTA was used to revise 96 failing grafts in 90 patients. Mean age was 65.8 years (range, 50-88 years), 64% were male, and 66% were symptomatic. Mean follow-up was 18.5 months (range, 3-24 months). Twenty-four grafts (25%) underwent repeat angioplasty for restenosis. Grafts with multiple lesions (P = .009) and grafts aged <6 months from the index operation (P = .004) were the only graft-related variables that showed a significant effect on the longevity of the endovascular revision. The PTA-revised grafts had primary, assisted primary, and secondary patency rates of 56.9%, 83.2%, and 90%, respectively, at 2 years.

CONCLUSIONS

Primary balloon angioplasty of failing lower extremity bypass grafts, notwithstanding the higher restenosis rate and the need for reintervention, appears to be safe and is associated with acceptable early and medium-term patency rates. Grafts with multiple lesions and those revised ≤6 months of the index operation showed a significant association with the need for a second revision at the same site.

Popliteal pseudoaneurysm and arteriovenous fistula after acupuncture

Most popliteal arteriovenous fistula and pseudoaneurysm formation are related to trauma. Few cases have previously been reported after acupuncture therapy. Such events are typically observed when the procedure is performed by non-medical acupuncturist. They may present with acute ischemia, recent claudication, distal emboli, or less commonly rupture. Duplex ultrasound should be considered as the 1st method of investigation. Computed tomography scanning is particularly accurate in making the diagnosis. Treatment strategies consist of surgery or endovascular management. The most commonly performed surgical technique for popliteal pseudoaneurysm repair is resection with bypass grafting, whereas popliteal arteriovenous fistula are usually treated surgically with ligation and primary repair. Endovascular procedure using a stent-graft is thought to be a reasonable option for treating popliteal false aneurysm or even arteriovenous fistula. We will describe two cases of an arteriovenous fistula and pseudoaneurysm of the popliteal artery that developed after acupuncture needling in the region of the popliteal artery.

Surveillance and follow-up after revascularization for critical limb ischemia

The purpose of a structured and cost-effective surveillance program after surgical or endovascular intervention for critical limb ischemia is to optimize limb salvage and preserve arterial repair function. Surveillance programs should include clinical, vascular laboratory, and radiographic follow-up, and, when a high-grade progressive stenosis is identified, appropriately timed intervention should be performed. Because many patients with critical limb ischemia are older and many are frail with limited mobility, optimizing the durability of arterial intervention and keeping these patients ambulatory is an important factor in retaining an independent lifestyle and quality of life. Despite the importance of surveillance after arterial intervention, there is a lack of consensus in the literature regarding the efficacy of surveillance, how it should be performed, and well-defined evidence-based guidelines. This review provides an up-to-date scrutiny on this topic and provides recommendations for optimal testing methods, limitations of surveillance testing, and when and how to intervene. These recommendations should be considered in the care of the patient with critical limb ischemia, but with the understanding that patients vary widely and care should be individualized.

Posttraumatic pseudoaneurysm of popliteal artery following total knee arthroplasty

We report a case of posttraumatic false aneurysm of popliteal artery after a total knee arthroplasty in an 82-year-old woman. This case is characterized by the distinct history of trauma to the popliteal fossa in the immediate postoperative period and the location of false aneurysm. In addition, the clinical symptoms were similar to those of deep vein thrombosis. The ultrasonographic examination and computed tomography (CT) angiography confirmed the diagnosis on 6(th) day after the surgery. Ultrasonographic examination 1 day later revealed no increase in the size of false aneurysm. She was treated with open surgical repair. Presenting the difficulty in the diagnosis, unusual location, etiology, and its management is the intention of this case report.

Treatment of failing vein grafts in patients who underwent lower extremity arterial bypass

PURPOSE

We attempted to determine risk factors for the development of failing vein graft and optimal treatment in patients with infrainguinal vein grafts.

METHODS

We retrospectively reviewed a database of patients who underwent infrainguinal bypass using autogenous vein grafts due to chronic atherosclerotic arterial occlusive disease of lower extremity (LE) at a single institute between September 2003 and December 2011. After reviewing demographic, clinical, and angiographic features of the patients with failing grafts, we analyzed those variables to determine risk factors for the development of failing grafts. To determine an optimal treatment for the failing vein grafts, we compared results of open surgical repair (OSR), endovascular treatment (EVT) and conservative treatment.

RESULTS

Two hundred and fifty-eight LE arterial bypasses using autogenous vein grafts in 242 patients were included in this study. During the follow-up period of 39 ± 25 months (range, 1 to 89 months), we found 166 (64%) patent grafts with no restenosis, 41 (15.9%) failing grafts, 39 (15.1%) graft occlusions, and 12 (4.7%) grafts lost in follow-up. In risk factor analysis for the development of a failing graft, no independent risk factors were identified. After 50 treatments of the 41 failing grafts (24 OSR, 18 EVT, 8 conservative management), graft occlusion was significantly more common in conservative treatment group and severe (>75%) restenosis was significantly more common following EVT than OSR (P = 0.001). Reintervention-free graft patency was also superior in the OSR group to that of the EVT group (87% vs. 42%, P = 0.015).

CONCLUSION

OSR of failing grafts has better outcomes than EVT or conservative management in treating failing grafts.

Surveillance after distal revascularization for critical limb ischaemia

Patients with critical limb ischaemia (CLI) are usually elderly and suffer from several co-morbidities. The goal of surveillance after both endovascular and surgical revascularization for CLI is not only the protection of re-established distal perfusion and sustained ambulation but also the reduction of systemic atherothrombotic risk and mortality by ensuring continued best medical care. However, preferred format and rhythm of structured follow-up programs have remained controversial, mainly because of lack of compelling evidence. This review aims to summarize and to appraise available information critically. Thereby, it underlines the importance of systematic surveillance after both surgical and endovascular revascularization for CLI. Recent European guidelines are considered and areas of uncertainty are highlighted and discussed. According to currently available literature and recent guidelines, the early duplex scan is justified in all patients undergoing endovascular or surgical distal revascularization for CLI. There is no best level evidence supporting continued long term duplex surveillance of revascularizations with normal findings at early duplex scan, whereas those patients with abnormal early duplex scan or high risk revacularization are likely to benefit from continued duplex surveillance. Regular clinical follow-up is suggested and clinical deterioration should trigger duplex scanning to ensure revascularization patency.

Chapter II: Diagnostic methods

Non-invasive vascular studies can provide crucial information on the presence, location, and severity of critical limb ischaemia (CLI), as well as the initial assessment or treatment planning. Ankle-brachial index with Doppler ultrasound, despite limitations in diabetic and end-stage renal failure patients, is the first-line evaluation of CLI. In this group of patients, toe-brachial index measurement may better establish the diagnosis. Other non-invasive measurements, such as segmental limb pressure, continuous-wave Doppler analysis and pulse volume recording, are of limited accuracy. Transcutaneous oxygen pressure (TcPO(2)) measurement may be of value when rest pain and ulcerations of the foot are present. Duplex ultrasound is the most important non-invasive tool in CLI patients combining haemodynamic evaluation with imaging modality. Computed tomography angiography (CTA) and magnetic resonance angiography (MRA) are the next imaging studies in the algorithm for CLI. Both CTA and MRA have been proven effective in aiding the decision-making of clinicians and accurate planning of intervention. The data acquired with CTA and MRA can be manipulated in a multiplanar and 3D fashion and can offer exquisite detail. CTA results are generally equivalent to MRA, and both compare favourably with contrast angiography. The individual use of different imaging modalities depends on local availability, experience, and costs. Contrast angiography represents the gold standard, provides detailed information about arterial anatomy, and is recommended when revascularisation is needed.

Chapter VI: Follow-up after revascularisation

Structured follow-up after revascularisation for chronic critical limb ischaemia (CLI) aims at sustained treatment success and continued best patient care. Thereby, efforts need to address three fundamental domains: (A) best medical therapy, both to protect the arterial reconstruction locally and to reduce atherosclerotic burden systemically; (B) surveillance of the arterial reconstruction; and (C) timely initiation of repeat interventions. As most CLI patients are elderly and frail, sustained resolution of CLI and preserved ambulatory capacity may decide over independent living and overall prognosis. Despite this importance, previous guidelines have largely ignored follow-up after CLI; arguably because of a striking lack of evidence and because of a widespread assumption that, in the context of CLI, efficacy of initial revascularisation will determine prognosis during the short remaining life expectancy. This chapter of the current CLI guidelines aims to challenge this disposition and to recommend evidentially best clinical practice by critically appraising available evidence in all of the above domains, including antiplatelet and antithrombotic therapy, clinical surveillance, use of duplex ultrasound, and indications for and preferred type of repeat interventions for failing and failed reconstructions. However, as corresponding studies are rarely performed among CLI patients specifically, evidence has to be consulted that derives from expanded patient populations. Therefore, most recommendations are based on extrapolations or subgroup analyses, which leads to an almost systematic degradation of their strength. Endovascular reconstruction and surgical bypass are considered separately, as are specific contexts such as diabetes or renal failure; and critical issues are highlighted throughout to inform future studies.

Stenosis of reverse great saphenous vein graft in infrainguinal arterial revascularization

OBJECTIVE

The aim of this study was to evaluate the prevalence of hemodynamically significant infrainguinal bypasses stenosis using reverse great saphenous vein graft.

METHODS

From March of 2008 to March of 2009, 56 infrainguinal bypasses were performed with reverse great saphenous vein graft in 56 patients. On the 30th post-operative day, 32 out of 56 patients were submitted to vascular ultrasonography. The prevalence of significant graft stenosis was determined. In addition, the diagnosis of stenosis was related to the clinical and surgical characteristics of the patients. The variables analyzed at the moment of diagnosis were the localization of the graft stenosis, the risk factors associated with stenosis and the association of vascular ultrasonography findings with ankle brachial pressure index (ABI).

RESULTS

The overall prevalence of significant graft stenosis was 48.4%. Out of the total number of observed stenosis, 19.4% were considered severe, and 29% mild or moderate. There was no significant association between the presence of significant stenosis and the following variables: gender, diabetes, hypertension, smoking, hipercholesterolemia, graft diameter, site of the distal anastomosis, and graft composition. There was a weak agreement between ABI and vascular ultrasonography in detecting stenosis in general (K = 0.30; CL95% 0.232 - 0.473; p = 0.018). However, there was a substantial agreement in detecting severe stenosis (K = 0.75; CL95% 0.655 - 0.811; p = 0.0001).

CONCLUSION

There was a high prevalence of stenosis on the 30th post-operative day, mostly localized in the proximal half of the vein graft. There was no significant association of stenosis with clinical and surgical factors analyzed. ABI and vascular ultrasonography had weak agreement with the diagnosis of stenosis in general and an important agreement for the diagnosis of severe stenosis.

Endovascular treatment for traumatic popliteal artery pseudoaneurysms after knee arthroplasty

Trauma to the popliteal artery is a recognized complication of knee arthroplasty (total knee arthroplasty). It can present in a variety of ways, one of which is the development of popliteal artery pseudoaneurysm. We report the successful endovascular management of 2 patients who developed popliteal artery pseudoaneurysms following total knee arthroplasty using covered stent grafts. From presented evidence, endovascular therapy is a safe treatment modality and it appears to be a viable alternative to open surgery.

Efficacy of duplex ultrasound surveillance after infrainguinal vein bypass may be enhanced by identification of characteristics predictive of graft stenosis development

OBJECTIVE

Controversy regarding the efficacy of duplex ultrasound surveillance after infrainguinal vein bypass led to an analysis of patient and bypass graft characteristics predictive for development of graft stenosis and a decision of secondary intervention.

METHODS

Retrospective analysis of a contemporary, consecutive series of 353 clinically successful infrainguinal vein bypasses performed in 329 patients for critical (n = 284; 80%) or noncritical (n = 69; 20%) limb ischemia enrolled in a surveillance program to identify and repair duplex-detected graft stenosis. Variables correlated with graft stenosis and bypass repair included: procedure indication, conduit type (saphenous vs nonsaphenous vein; reversed vs nonreversed orientation), prior bypass graft failure, postoperative ankle-brachial index (ABI) < 0.85, and interpretation of the first duplex surveillance study as "normal" or "abnormal" based on peak systolic velocity (PSV) and velocity ratio (Vr) criteria.

RESULTS

Overall, 126 (36%) of the 353 infrainguinal bypasses had 174 secondary interventions (endovascular, 100; surgery, 74) based on duplex surveillance; resulting in 3-year Kaplan-Meier primary (46%), assisted-primary (80%), and secondary (81%) patency rates. Characteristics predictive of duplex-detected stenosis leading to intervention (PSV: 443 +/- 94 cm/s; Vr: 8.6 +/- 9) were: "abnormal" initial duplex testing indicating moderate (PSV: 180-300 cm/s, Vr: 2-3.5) stenosis (P < .0001), non-single segment saphenous vein conduit (P < .01), warfarin drug therapy (P < .01), and redo bypass grafting (P < .001). Procedure indication, postoperative ABI level, statin drug therapy, and vein conduit orientation were not predictive of graft revision. The natural history of 141 (40%) bypasses with an abnormal first duplex scan differed from "normal" grafts by more frequent (51% vs 24%, P < .001) and earlier (7 months vs 11 months) graft revision for severe stenosis and a lower 3-year assisted primary patency (68% vs 87%; P < .001). In 52 (15%) limbs, the bypass graft failed and 20 (6%) limbs required amputation.

CONCLUSIONS

The efficacy of duplex surveillance after infrainguinal vein bypass may be enhanced by modifying testing protocols, eg, rigorous surveillance for "higher risk" bypasses, based on the initial duplex scan results and other characteristics (warfarin therapy, non- single segment saphenous vein conduit, redo bypass) predictive for stenosis development.