Iliac Artery Stenosis Research Articles

Endovascular management of vascular complications in renal allograft - An observational study

Context: Role of endovascular management of vascular complications in renal transplant recipients. Aims: To present our experience in endovascular management of vascular complications in renal transplant recipients with a literature review. Settings and Design: A retrospective observational study. Materials and Methods: This is a retrospective analysis of postrenal transplant recipients referred to our department for the evaluation and endovascular management of vascular complications from January 2010 to December 2014. Cases of transplant renal artery stenosis (TRAS) and common iliac artery (CIA) stenosis were treated with percutaneous transluminal balloon angioplasty with or without stenting. Intraparenchymal pseudoaneurysms, arteriovenous fistula (AVF), and active contrast extravasation cases were managed with coil and/or glue embolization. Treated patients were followed up with serial blood pressure measurements, serum creatinine estimation, and Doppler evaluation in the postprocedure period and at 3-month and 6-month intervals. Results: Among a total of ten patients, there were five TRAS, two intraparenchymal pseudoaneurysms with active contrast extravasation, one AVF, one active renal bleed with peri-graft hematoma, and one right CIA stenosis. Intraparenchymal pseudoaneurysms, AVF, and active extravasations were postbiopsy. All treated patients showed improved renal function, increased hematocrit, improved blood pressure control in the postprocedure period, and follow-up. Conclusions: Vascular complications in renal transplant patients may lead to graft dysfunction, increased morbidity, and even graft loss if left untreated. Endovascular interventions are first-line treatments with excellent short- and long-term outcomes.

COVID-19-INDUCED AORTIC THROMBOSIS

TOPIC: Chest Infections TYPE: Medical Student/Resident Case Reports INTRODUCTION: As of April 2021, Coronavirus disease (COVID-19) has infected over 147 million people and claimed the lives of over 3 million globally. Despite becoming a significant burden on the healthcare community, complications and sequalae of this lethal virus are still not fully known. While primarily being defined as a respiratory illness, COVID-19 has been known to cause venous thrombotic events and less commonly increased arterial clot burden. CASE PRESENTATION: A 63-year-old female with a history of 30 pack year tobacco use presented to the emergency department (ED) complaining of shortness of breath, chest tightness, and right lower extremity pain starting 2-3 hours prior to presentation. In the ED she was noted to be COVID-19 positive and found to be hypoxic with an oxygen saturation of 84% on room air for which she was placed on 4 liters of oxygen per minute via nasal cannula for a goal oxygen saturation of >92%. The remainder of her vitals were unremarkable and physical exam did not reveal any pathology or acute findings. An emergent CT angiogram of the chest, abdomen, and pelvis was obtained which showed a large focus of thrombus in the ascending thoracic aorta measuring up to 2.2 x 1.3 cm in the axial plane, which appears free-floating abutting the anterior wall of the aorta. There were also some smaller scattered eccentric thrombi in the descending thoracic and infrarenal abdominal aorta. A focus of thrombus extending from the distal abdominal aorta into the right common iliac artery results in severe stenosis of the right common iliac artery. Venous doppler studies revealed diminished velocity in the right popliteal and posterior tibial arteries without identified thrombosis. Vascular surgery was consulted however the patient remained clinically stable and was started on a heparin drip prior to being bridged to warfarin with a goal international normalized ratio of 2.5 to 3.5 for a total of 6 months duration. At her 1 and 3 month outpatient follow-up she remained in stable condition and her presenting symptoms resolved. DISCUSSION: COVID-19 is known to bind to the peptidase domain of the angiotensin-converting enzyme 2 receptor leading to severe respiratory disease and an overwhelming activation of cytokines and complements. Through this process, a hypercoagulable state is induced leading to venous and arterial thrombotic events. Our patient had no risk factors for thrombotic disease and hypercoagulable work-up was largely unremarkable leading to the suspicion of COVID-19 infection as the cause. CONCLUSIONS: COVID-19 infection is a lethal viral disease affecting millions of people globally. As this disease continues to spread, it is imperative clinicians become aware of the devastating complications such as venous and arterial thrombosis risk and appropriately anti-coagulate their patients. REFERENCE #1: Ji YL, Wu Y, Qiu Z, et al. The Pathogenesis and Treatment of COVID-19: A System Review. Biomed Environ Sci. 2021;34(1):50-60. doi:10.3967/bes2021.007 REFERENCE #2: Cevik M, Kuppalli K, Kindrachuk J, Peiris M. Virology, transmission, and pathogenesis of SARS-CoV-2. BMJ. 2020;371:m3862. doi: 10.1136/bmj.m3862. DISCLOSURES: No relevant relationships by Abbas Alshami, source=Web Response No relevant relationships by Steven Douedi, source=Web Response No relevant relationships by Mihir Odak, source=Web Response No relevant relationships by Swapnil Patel, source=Web Response

Thrombosis of the right iliac, femoral, popliteal, and tibial arteries in a post-COVID-19 in adolescent

BackgroundViral infection into lung, muscular, and endothelial cells results in inflammatory response, including edema, degeneration, and necrotic alterations. The involvement of the major arteries in adolescent with COVID-19 has been infrequently reported in the literature. The aim of the present study is to report thrombosis of the right iliac, femoral and tibial arteries and stenosis of left iliac artery in an adolescent with COVID-19 and to discuss the pathophysiological hypotheses.Case presentationWe report the case of a 17-year-old female patient with COVID-19 infection. She was seen at the physician specialized general medicine in her hometown, was diagnosed with COVID-19 but did not require hospitalization. After 15 days, she had sudden pain in the left leg that has limited her ability to walk more than 10 met, associated with extremity cyanosis and coldness. Angiotomography revealed thrombosis of a portion of the iliac and popliteal arteries. Na emergency embolectomy was successfully performed, followed by full-dose heparinization with unfractionated heparin.ConclusionArterial thrombosis of large arteries may be associated with chronic inflammatory syndrome secondary to COVID-19 infection and the treatment with a late embolectomy was successful, even in a thrombotic event.

Increased collateral flow by rescue femorofemoral bypass dissolved residual thrombus in implanted iliofemoral artery stents: a case report

BackgroundFailed aortofemoral and femoropopliteal bypass grafts in the lower extremity artery usually result in acute limb ischemia. Endovascular treatment and surgical revascularization have been reported for limb salvage.Case presentationA 72-year-old Japanese man was admitted with acute limb ischemia due to failed aortofemoral and femoropopliteal bypass grafts. Endovascular treatment with balloon angioplasty, thrombectomy, and stent implantation in the long chronic total occlusion from the right common iliac artery to the superficial femoral artery did not result in efficient flow due to thrombus transfer from a failed aortofemoral bypass graft. However, a rescue femorofemoral bypass (the left femoral to the right deep femoral artery) improved his symptoms, and implanted in-stent flow was gradually recovered. Lower extremity angiography performed 5 months later confirmed the patency of the iliofemoral in-stent flow. However, the femorofemoral bypass graft was unfortunately occluded due to the progression of left external iliac artery stenosis. The patency of the iliofemoral in-stent flow was confirmed at 1 year by ultrasonography.ConclusionsImprovement of the deep femoral artery flow plays an important role in the treatment of acute limb ischemia due to failed aortofemoral and femoropopliteal bypass grafts. Thus, increased collateral circulation to the periphery through the deep femoral artery dissolved the remaining in-stent thrombus in the iliofemoral artery.

A Case of an Ischemic Regio Sacralis Ulcer Due to Internal Iliac Artery Stenosis Resembling Clinical Presentation of Deep Tissue Injury

A Case of an Ischemic Regio Sacralis Ulcer Due to Internal Iliac Artery Stenosis Resembling Clinical Presentation of Deep Tissue Injury

Image-based computational fluid dynamics for estimating pressure drop and fractional flow reserve across iliac artery stenosis: A comparison with in-vivo measurements.

Computational Fluid Dynamics (CFD) and time-resolved phase-contrast magnetic resonance imaging (PC-MRI) are potential non-invasive methods for the assessment of the severity of arterial stenoses. Fractional flow reserve (FFR) is the current "gold standard" for determining stenosis severity in the coronary arteries but is an invasive method requiring insertion of a pressure wire. CFD derived FFR (vFFR) is an alternative to traditional catheter derived FFR now available commercially for coronary artery assessment, however, it can potentially be applied to a wider range of vulnerable vessels such as the iliac arteries. In this study CFD simulations are used to assess the ability of vFFR in predicting the stenosis severity in a patient with a stenosis of 77% area reduction (>50% diameter reduction) in the right iliac artery. Variations of vFFR, overall pressure drop and flow split between the vessels were observed by using different boundary conditions. Correlations between boundary condition parameters and resulting flow variables are presented. The study concludes that vFFR has good potential to characterise iliac artery stenotic disease.

Internal Iliac Artery Stenosis: Diagnosis and How to manage it

Lower limit blood vessel sickness (LEAD) might be an exceptionally pervasive illness basically brought about by atherosclerosis, a fundamental infection measure that adjusts the conventional construction and execution of the vessels. Along these lines, LEAD hazard factors are very much distinguished: non-modifiable danger factors like age, sexual orientation, and heredity; and modifiable danger factors like smoking, hypertension, diabetes, and dyslipidemia.

Proximal Iliac Artery Stenosis in Allograft Renal Transplant, a Diagnostic beyond Echo-Doppler, Treatment Approach

Background: Transplant Renal Artery Stenosis (TRAS) is a well-known vascular complication after a kidney transplant. It is associated with premature renal failure, uncontrolled hypertension, and allograft loss. However, Proximal Iliac Artery Stenosis to a Kidney Transplant (Prox-TRAS) is an uncommon cause of vascular graft complication leading to acute renal failure and refractory hypertension with a less incidence around and only a few cases reports have been described in the medical literature. Methods: We reviewed the medical record of kidney transplant recipients of the General Hospital of Ciudad Real, Spain, from March 2008 to March 2019. We identified all cases (260) with the diagnosis of renal vascular hypertension by imaging studies. Of those 260 renal vascular stenoses, five (5) were diagnosed with proximal iliac artery stenosis through Angio-CT and arteriography. We performed an analysis of clinical parameters and evolution. Results: Prox-TRAS was diagnosed in 5 of the 260 patients who presented acute or progressive allograft dysfunction with refractory hypertension, with an incidence rate of 1.4%. In 4 of them (1.1%), we had to resort to another imaging test, angio-CT, arteriography, as the echo-doppler was unable to identify the abnormalities. Hypertension was a constant finding along with impaired renal function (100%); with respect to Prox-TRAS, its onset was later (12 - 60 months) after transplantation. An increase in TA (140 ± 10 and 80.7 ± 7 to 160 ± 18 and 85 ± 7 mmHg, p-0.009) was observed. There was an increase in the use of hypotensive drugs (2.1 ± 1.1 and 4.3 ± 1, p-0.003). Similarly, in all cases, a worsening of basal creatinine from 0.9 to 0.1 ± to 1.2 ± (P × 0.004) was also observed. Prox-TRAS was a cause of the increase in both creatinine and TA (140 ± 10 and 80.7 ± 7 to 160 ± 18 and 85 ± 7 mmHg, P 0.009). All cases were treated by Percutaneous transluminal angioplasty with stent placement, N= 5. In the follow-up, improvement was obtained from the claudication clinic as well as renal function and blood pressure, CRB (from 2.7 ± 1.4 to 1.8 ± 0.4 mg/dL, P-0.02) and TA (160 ± 18/85 ± 7mmHg at 138 ± 7/82 ± 9, p 0.018). Kidney function, blood pressure remained unchanged during follow-up (130 ± 36 months). Conclusion: Through these cases review, we propose highlighting the importance of extending imaging studies to the iliac artery of the kidney graft in case of high suspected renal vascular hypertension; showing the role and safety of angioplasty as a reasonable and effective treatment in the identified cases. We assessed the possibility of the limited role of Duplex Sonography (DS) regarding clinical and angiographic. PTA is the appropriate initial treatment of Prox-TRAS, with low morbidity and mortality rates, achieving improvement of graft function and amelioration of hypertension.

Angioplasty versus stenting for iliac artery lesions

Angioplasty versus stenting for iliac artery lesions

ROLE OF ENDOVASCULAR INTERVENTION IN ILIAC ARTERY DISEASE TASC C AND D CLASSIFICATION

Background: For more than forty years, endarterectomy and bypass grafting have been the primary means of surgically revascularizing peripheral vessels threatened by atherosclerotic diseases. However, with today's endovascular technology, stenosis and occlusions in nearly every circulatory system can he approached intraluminally with balloon dilation and intravascular stents. Objective: To evaluate the technical success rates, primary patency, limb salvage, patient survival and complications for TASC C, and D iliac lesions treated by endovascular procedure. Additionally, the influence of the access site and the clinical outcomes were analyzed. Patients and Method: Between 2017 and 2019, data from 40 consecutive patients at Al-Zahra’a University Hospital and Damanhor Teaching Hospital with 47 chronic iliac artery stenosis, and/or occlusion who were treated with EVT were reviewed. Results: The procedure time was longer for TASC D lesions than for TASC C lesions (180.43 ± 45.97 VS131.69 ± 37.49: p= 0.001). There were two postoperative deaths in the TASC D lesion group, with the cause being one myocardial infarction, and one postoperative hospital acquired pneumonia. The total perioperative complication occurred in the TASC D lesions was [four (10%) vs. zero; p = 0.011] TASC C lesions. Corresponding 2-year primary patency rates were 100% in TASC C lesions, 71.4% in TASC D lesions, and for all cases were 87.5%. Conclusion: The outcomes of EVT for TASC C and D aorto-iliac lesions were acceptable, with better technical success in TASC C lesions than in TASC D lesions. The 2-year patency rate for both TASC C and TASC D lesions was acceptable, and brachial access was useful for complex anatomy.

ROLE OF ENDOVASCULAR INTERVENTION IN ILIAC ARTERY DISEASE TASC C AND D CLASSIFICATION

Background: For more than forty years, endarterectomy and bypass grafting have been the primary means of surgically revascularizing peripheral vessels threatened by atherosclerotic diseases. However, with today's endovascular technology, stenosis and occlusions in nearly every circulatory system can he approached intraluminally with balloon dilation and intravascular stents. Objective: To evaluate the technical success rates, primary patency, limb salvage, patient survival and complications for TASC C, and D iliac lesions treated by endovascular procedure. Additionally, the influence of the access site and the clinical outcomes were analyzed. Patients and Method: Between 2017 and 2019, data from 40 consecutive patients at Al-Zahra’a University Hospital and Damanhor Teaching Hospital with 47 chronic iliac artery stenosis, and/or occlusion who were treated with EVT were reviewed. Results: The procedure time was longer for TASC D lesions than for TASC C lesions (180.43 ± 45.97 VS131.69 ± 37.49: p= 0.001). There were two postoperative deaths in the TASC D lesion group, with the cause being one myocardial infarction, and one postoperative hospital acquired pneumonia. The total perioperative complication occurred in the TASC D lesions was [four (10%) vs. zero; p = 0.011] TASC C lesions. Corresponding 2-year primary patency rates were 100% in TASC C lesions, 71.4% in TASC D lesions, and for all cases were 87.5%. Conclusion: The outcomes of EVT for TASC C and D aorto-iliac lesions were acceptable, with better technical success in TASC C lesions than in TASC D lesions. The 2-year patency rate for both TASC C and TASC D lesions was acceptable, and brachial access was useful for complex anatomy.

Prospective Screening of Extracranial Systemic Arteriopathy in Young Adults with Moyamoya Disease.

Background RNF213 is a major susceptibility gene for moyamoya disease (MMD), characterized by chronic progressive steno‐occlusion of the intracranial arteries. However, coincidental extracranial arteriopathy is sporadically described in a few cases and in children with MMD.Methods and ResultsThis study prospectively enrolled 63 young adults (aged 20–49 years) without a known history of systemic vascular diseases who were confirmed to have definite (bilateral, n=54) or probable (unilateral, n=9) MMD, as per typical angiographic findings. Coronary and aorta computed tomography angiography was performed to characterize extracranial arteriopathy and investigate its correlation with clinical characteristics and MMD status, including the RNF213 p.Arg4810Lys variation (c.14429G>A, rs112735431). Altogether, 11 of 63 patients (17%) had significant (>50%) stenosis in the coronary (n=6), superior mesenteric (n=2), celiac (n=2), renal (n=1), and/or internal iliac artery (n=1). One patient showed both mesenteric and iliac artery stenosis. Patients with extracranial arteriopathy were more likely to have diabetes mellitus and posterior cerebral artery involvement. Moreover, a higher prevalence of extracranial arteriopathy was observed in the presence of the RNF213 p.Arg4810Lys variant (67% in homozygotes). After controlling for diabetes mellitus and posterior cerebral artery involvement, the p.Arg4810Lys variant was independently associated with extracranial arteriopathy (additive model; P=0.035; adjusted odds ratio, 4.57; 95% CI, 1.11–27.20).ConclusionsYoung adults with MMD may have concomitant extracranial arteriopathy in various locations. Patients with RNF213 variants, especially the p.Arg4810Lys homozygous variant, should be screened for systemic arteriopathy.

The Efficacy of a Protocol of Iliac Artery and Limb Treatment During EVAR in Minimising Early and Late Iliac Occlusion

Iliac limb occlusion (ILO) is a complication of endovascular aortic repair (EVAR) and requires re-intervention in most cases. Attention to any intra-operative defect of iliac limbs and arteries may prevent ILO. The study aimed to analyse the long term effect of an intra-operative protocol of iliac limb treatment during EVAR on ILO. Patients treated from 2012 to 2017 for abdominal aortic aneurysm (AAA) with standard EVAR were collected prospectively. Pre-operative computed tomography angiography anatomical characteristics were evaluated. The protocol for intra-operative iliac limb management was: a. pre-EVAR angioplasty of common/external iliac artery stenosis; b. precise contralateral iliac limb deployment at the same level of the flow divider; c. iliac limb kissing ballooning with high pressure non-compliant balloons; d. iliac limb stenting for residual tortuosity/kink and adjunctive external iliac stenting for residual stenosis/dissection after EVAR. ILO was evaluated at 30 days and at follow up, which was performed by duplex ultrasonography before discharge, at three, six, and 12 months and yearly thereafter. Kaplan-Meier and Cox linear regression were used. Four hundred and forty-two patients and 884 iliac limbs were included in the study. Severe iliac tortuosity and calcification were present in 15% (132/884) and 8% (70/884), respectively. External iliac angioplasty and stenting of iliac limb were performed in 2% (18/884) and 9.5% (84/884) of limbs. The thirty day mortality was 1.6%, with no ILO. At a mean follow up of 33±12 months, ILO occurred in 7/884 (0.8%) limbs of six patients. Five ILO were treated by endovascular relining, two surgically: one by femorofemoral bypass and one by surgical explant. On univariable analysis, sac shrinkage was significantly associated with ILO (HR 1, 95% CI 0.8-2.5, p=.043). A protocol of aggressive iliac limb treatment in EVAR leads to a very low rate of late ILO. The role of sac shrinkage in ILO should be investigated further.

Long Distance Triathlete With Iliac Endofibrosis

A 48 year old long distance triathlete complained of exercise induced thigh pain on the left side for several years. Physical examination in the presence of strongly palpable foot pulses was uneventful at rest, but there was a drop in ankle brachial index (ABI) to 0.4 after exercise. Magnetic resonance angiography (MRA) revealed a mild stenosis of the external iliac artery (EIA) on the left side (A). Through extraperitoneal access, a high grade stenosis became apparent (B). After vein patch plasty and an uneventful post-operative recovery, the athlete was able to increase training intensity free of pain.Image 1

Role of Endovascular Intervention in Iliac Artery Disease TASC C and D Classification

Abstract Background: For more than forty years, endarterectomy and bypass grafting have been the primary means of surgically revascularizing peripheral vessels threatened by atherosclerotic disease. However, with today's endovascular technology, stenosis and occlusions in nearly every circulatory system can he approached intraluminally with balloon dilatation and intravascular stents. Aim of Study: Was to evaluate the technical success rates, primary patency, limb salvage, patient survival and compli-cations for TASC C and D iliac lesions treated by endovascular procedure. Additionally, the influence of the access site and the clinical outcomes were analyzed. Patients and Methods: Between 2017 and 2019, data from 40 consecutive patients at Al-Zahraa University Hospital and Damanhor Teaching Hospital with 47 chronic iliac artery stenosis and/or occlusion who were treated with EVT were reviewed. Results: The procedure time was longer for TASC D lesions than for TASC C lesions (180.43±45.97 vs. 131.69± 37.49: p=0.001). There were two post-operative deaths in the TASC D lesion group, with the cause being one myocardial infarction and one post-operative hospital acquired pneumonia. The total perioperative complication rate was higher in the TASC D lesions than in TASC C lesions [four (10%) vs. zero; p=0.011]. Corresponding 2-year primary patency rates were 100% in TASC C lesions, 71.4% in TASC D lesions and for all cases were 87.5%. Conclusion: This study demonstrated that the outcomes of EVT for TASC C and D aorto-iliac lesions were acceptable, with better technical success in TASC C lesions than in TASC D lesions. Furthermore, the 2-year patency rate for both TASC C and TASC D lesions was acceptable, and brachial access was useful for complex anatomy.

TRANSPLANT RENAL ARTER STENOZU: TEK MERKEZ DENEYİMİ

<div><!--block-->Objective: Transplant renal artery stenosis (TRAS) and post-transplant arterial hypertension is a treatable cause of allograft dysfunction and graft loss. The risk factors for the development of TRAS include: donor age, prolonged and delayed graft function, cold ischemia time,concomitant CMV infection and surgical technique. Percutaneous transluminal angioplasty (PTA) has proven successful in treating TRAS in 60-90% of cases by providing renal reperfusion. In this study,we evaluated six TRAS cases in our clinic.&nbsp;<br><br>Material and Method: We evaluated patients retrospectively from medical records who underwent transplantation in 2017. We recorded the age, gender, creatinine, other findings during transplantation, and the demographic features of transplant patients with TRAS.&nbsp;<br><br>Results: TRAS was reported in 6 of 26 cases. The presence of iliac artery stenosis associated with renal artery stenosis was seen in two patients with CMV PCR (+). Patients underwent PTA and stent implantation. The need for antihypertensive treatment of the patients lessened during follow-up.&nbsp;<br><br>Conclusion: TRAS is one of the reasons for allograft dysfunction after kidney transplantation. For this reason it should be kept in mind when determining the cause of the allograft disfunction. In addition to other risk factors, surgical technique plays an important role in the development of TRAS. Graft function can be preserved with early intervention.</div>

Retroperitoneal Fibrosis Secondary to the Placement of Aorto-iliac Stents

Introduction: Retroperitoneal fibrosis (RF) is a rare disorder characterized by inflammation and fibrosis in the periphery of the abdominal aorta (1). In about two thirds of the cases this condition is idiopathic (2). It is known that inflammatory aneurysms could be associated with RF and regression of periaortic inflammation after endovascular treatment (EVAR) of the aneurysm was described (3). However, very little is known about the possibility of this condition being associated with the implantation of endovascular devices. In the literature there is only one report of a clinical case in which the RF was secondary to the implantation of a kissing stent of the common iliac arteries (4). Periaortitis and periaortic fibro-inflammatory alterations secondary to stent graft implantation in the correction of abdominal aortic aneurysms have also been demonstrated, with 5 cases described in the literature (5,6,7,8,9). In some of these cases, patients presented complications of RF, such urethral obstruction with hydronephrosis. Possibly, since the symptoms of the disease are non-specific, the condition tends to be underreported and underdiagnosed. The pathophysiology of this pathological process is not known; however, it was proposed that the angioplasty and stenting can disturb plaque integrity with antigen exposure, triggering a local inflammatory response (10). Methods: We describe two cases of retroperitoneal fibrosis secondary to endovascular intervention of arterial aortic iliac axes with angioplasty and stent/stent-graft placement. Results: We present our experience with two patients with Leriche Fontaine IIb arteriopathy, one with pre-occlusive stenosis of the left common iliac artery treated with percutaneous transluminal angioplasty (PTA) and stenting, other with morphologically significant stenosis of the infrarenal abdominal aorta where PTA and kissing stent with two aortoiliac stent-grafts was performed. Following the endovascular procedure, both patients had manifested marked lumbar pain and elevation of serum inflammatory markers. A periaortic inflammatory process suggestive of retroperitoneal fibrosis was visualized on computed tomography angiography (CTA). In both patients the clinical condition was reverted with steroid therapy without recurrence of symptoms. Conclusion: These cases demonstrate the possible relationship between the implantation of aortoiliac stents and the development of retroperitoneal fibrosis. The published literature is very scarce. This complication, like all forms of chronic periaortitis, responds well to corticotherapy with symptom resolution. Disclosure: Nothing to disclose

Supervised Exercise Therapy or Endovascular Revascularization for Patients with Intermittent Claudication due to an Iliac Artery Obstruction? The Super Study

Introduction - The optimal treatment strategy for patients with intermittent claudication (IC) due to an iliac artery obstruction is as yet unclear. Should patients be referred for immediate Percutaneous Transluminal Angioplasty (PTA) or supervised exercise therapy (SET) and deferred PTA if SET fails? Methods - This multi-center randomized controlled trial included 240 patients from 18 hospitals in the Netherlands with IC due to a > 50% common or external iliac artery stenosis or occlusion, and a walking distance 100-300 meters on a treadmill (3.2 km/h, 10% incline). Patients were randomly allocated to PTA with or without stent, or SET, stratified for maximum walking distance (MWD) at baseline and concomitant SFA stenosis or occlusion. PTA was carried out according to local practice. SET comprised a 6 months program supervised by a dedicated physiotherapist twice a week during the first 12 weeks, once a week during the next 8 weeks and once every two weeks during the last 4 weeks. Primary endpoints were MWD on a treadmill (3.2 km/h, 10% incline) and disease specific quality of life (Qol) measured with the VascuQol questionnaire after 1 year follow-up. Analysis was performed according to the intention-to-treat principle. To take into account the repeated measurements structure of the data differences between MWD and VascuQol sumscore were assessed with a linear mixed model with a Toeplitz covariance structure. Results - Between November 2010 and May 2015, 114 patients were allocated to SET, 126 to PTA. Compliance to SET was poor; after 1 month 75/114 (66%) patients attended the program, declining to 68/114 (60%) and 57/114 (50%) after 3 and 6 months, respectively. Ten (8%) of the patients allocated to PTA did not receive the intervention, which was technically successful in 112/116 (97%) of the remaining patients. Five patients had a minor complication after PTA and 6 a major complication necessitating endovascular or surgical resolution. Some 90/114 (79%) patients allocated to SET completed one year follow-up, and 104/126 (83%) allocated to PTA. The mean MWD improved from 187 to 561 meters in the SET group and from 196 to 574 meters in the PTA group, (p=0.693) The VascuQol sumscore improved from 4.24 in the SET group to 5.58, and from 4.28 in the PTA group to 5.88, (p=0.048). Yet, in both groups the improvement in VascuQol sumscore was more than the minimally important clinical difference of 1.19 (derived from 100 participants of the SUPER study). Some 33/114 (29%) of patients allocated to SET had a PTA within one year, and 2/114 (2%) additional surgical revascularization (SR). Some 10/126 (8%) patients allocated to PTA had an additional PTA within one year and another 10/126 (8%) had SR. Conclusion - Both a strategy of immediate PTA, and SET with deferred PTA in case of SET failure improve MWD on a treadmill and disease specific Qol of patients with IC due to an iliac artery obstruction. It seems reasonable to start with SET in these patients and accept a 30% failure rate. The cost-effectiveness analysis of this RCT will further define clinical decision making.

A Metamodeling Approach for Instant Severity Assessment and Uncertainty Quantification of Iliac Artery Stenoses.

Two-dimensional (2D) or three-dimensional (3D) models of blood flow in stenosed arteries can be used to patient-specifically predict outcome metrics, thereby supporting the physicians in decision making processes. However, these models are time consuming which limits the feasibility of output uncertainty quantification (UQ). Accurate surrogates (metamodels) might be the solution. In this study, we aim to demonstrate the feasibility of a generalized polynomial chaos expansion-based metamodel to predict a clinically relevant output metric and to quantify the output uncertainty. As an example, a metamodel was constructed from a recently developed 2D model that was shown to be able to estimate translesional pressure drops in iliac artery stenoses (-0.9 ± 12.7 mmHg, R2 = 0.81). The metamodel was constructed from a virtual database using the adaptive generalized polynomial chaos expansion (agPCE) method. The constructed metamodel was then applied to 25 stenosed iliac arteries to predict the patient-specific pressure drop and to perform UQ. Comparing predicted pressure drops of the metamodel and in vivo measured pressure drops, the mean bias (-0.2 ± 13.7 mmHg) and the coefficient of determination (R2 = 0.80) were as good as of the original 2D computational fluid dynamics (CFD) model. UQ results of the 2D and metamodel were comparable. Estimation of the uncertainty interval using the original 2D model took 14 days, whereas the result of the metamodel was instantly available. In conclusion, it is feasible to quantify the uncertainty of the output metric and perform sensitivity analysis (SA) instantly using a metamodel. Future studies should investigate the possibility to construct a metamodel of more complex problems.

Prevention of neointimal formation after angioplasty using tetramethylpyrazine-coated balloon catheters in a rabbit iliac artery model.

Restenosis remains a clinical problem; drug-coated balloons (DCBs) have demonstrated high efficiency in this situation. DCBs prevent neointimal hyperplasia by inhibiting cell proliferation and migration. Tetramethylpyrazine (TMP) is a traditional Chinese medicine originally isolated from the rhizome of Ligusticum Walliichii, which can inhibit platelet aggregation and smooth muscle cell proliferation. We hypothesized that TMP-coated balloons (TCB) could reduce neointimal hyperplasia through the NF-κB signalling pathway. Twenty-one New-Zealand White rabbits (2.5-3.0 kg, male) were fed high-fat diets; 36 bilateral iliac artery stenosis models were successfully established by balloon straining. Rabbits were randomly treated with TCB (n=20) or plain balloons (PBA, n=16) (3 died during model construction). Angiographies were recorded at baseline, the immediate period, and 4 weeks later. Animals were euthanized and arteries collected for histological analysis and immunohistochemical staining. Protein expression of proliferating cell nuclear antigen (PCNA) and nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) p65 of the vessel samples were analyzed using Western blotting. No difference existed in the baseline lesion characteristics or procedural results. Angiographic follow-up was successfully performed on 18 rabbits (TCB: n=20, PBA: n=16), except for 3 deaths related to the operation. Treatment with TCB was superior to that with PBA, with lower late lumen loss (0.45±0.23 vs. 0.84±0.17 mm, P<0.01). Pathological analysis confirmed the efficiency of TCB through decreasing the area stenosis rate compared with PBA (46.48%±8.22% vs. 75.24%±6.10%, P<0.01). As determined by Western blotting, significant reductions occurred in PCNA and NF-κB p65 protein intensity in the TCB group versus the PBA group (all P<0.01). TCB efficiently mitigated restenosis in the rabbit iliac artery model. This study elucidated that TCB could restrain intimal hyperplasia of vessels by inhibiting the activation of the NF-κB pathway to reduce inflammatory response and decrease the rate of cell proliferation through suppressing PCNA expression.