Noninvasive Duplex Research Articles

Location of venous reflux in our duplex test of patients with primary chronic venous insufficiency and comparison with that of the literature

Background: Chronic venous insufficiency (CVI) significantly impacts patients’ quality of life and poses economic burdens on healthcare systems. Accurate assessment of venous reflux is crucial for effective management. This study aimed to identify the sites of deep, superficial, and perforator venous reflux, including junctional incompetencies between superficial and deep veins in patients with primary CVI. Methods: A prospective observational study was conducted from July 1, 2022 to June 30, 2024, utilizing non-invasive Duplex ultrasonography on patients in our clinical practice. Data were collected without patient identification, and informed consent was obtained prior to procedures. Reflux was defined as venous flow reversal lasting over 0.5 seconds. Results: A total of 50 limbs from patients aged 20 to 77 years (mean age 43) were examined, with a male-to-female ratio of 52:48. Reflux was detected in the external iliac (41 limbs), common femoral (39 limbs), superficial femoral (21 limbs), popliteal (26 limbs), posterior tibial (7 limbs) and perforator veins (21 limbs). Sapheno-femoral junction incompetency was observed in 28 cases, with 6 cases indicating early-stage reflux. Dilatation of the great saphenous vein was noted in 33 cases, while 14 cases exhibited short saphenous vein dilatation. Conclusions: The detection of venous reflux reveals significant insights for diagnosing and managing CVI. This study highlights areas for improvement in Duplex examination techniques, advocating for enhanced training for healthcare professionals to elevate diagnostic standards, ultimately benefiting patient outcomes and reducing societal burdens associated with CVI.

Manifestations of circulatory assist devices in noninvasive arterial duplex evaluation: A pictorial review.

Spectral Doppler and plethysmographic waveforms vary significantly in the presence of circulatory assist devices. Understanding the effect these devices have on the waveforms and flow characteristics is necessary for the appropriate interpretation of duplex ultrasound and other noninvasive vascular studies. We review the different arterial waveforms that can be seen with circulatory assist devices.

Analysis of Influencing Factors for Postoperative Venous Thromboembolism of Thymic Malignancies

背景与目的胸外科术后静脉血栓栓塞症（venous thromboembolism, VTE）的发生率高，本研究旨在分析胸腺恶性肿瘤术后VTE的发生率及相关危险因素。方法本研究为单中心研究。收集2017年12月-2021年2月在首都医科大学附属北京同仁医院胸外科接受胸腺恶性肿瘤切除手术治疗的患者资料。除术前常规检查以外，所有患者于手术前后行下肢多普勒超声以明确有无下肢深静脉血栓（deep venous thrombosis, DVT）。患者术前术后均未接受任何形式抗凝治疗。全部患者接受改良Caprini风险评估。根据术后是否发生VTE将患者分为VTE组和对照组，比较两组间的临床资料，统计术后VTE的发生时间、可能的高危因素等。结果共纳入169例接受胸腺恶性肿瘤切除手术的患者，男性94例，女性75例，年龄范围：22岁-76岁。本研究共95例患者选择胸腔镜手术，74例选择正中劈胸骨手术。全组共21例发生VTE，VTE的总发生率为12.4%。诊断VTE的中位时间为术后4 d（2 d-15 d）。根据改良Caprini评分分组，低危组（≤4分)发生率为0%（0/7），中危组（5分-8分）为7.0%（8/115），高危组（≥9分）为27.7%（13/47）（Z=1.670, P=0.008）。单因素分析结果显示VTE组年龄、手术方式、手术时间、留置中心静脉导管、术后卧床时间超过72 h均与对照组有显著差异（P < 0.05）。多因素分析结果显示年龄≥60岁、手术方式、手术时长是胸腺恶性肿瘤术后发生VTE的独立危险因素。结论年龄≥60岁、手术方式、手术时长是胸腺恶性肿瘤患者术后发生VTE的独立危险因素，改良Caprini评分可有效筛选高危患者。

New diagnostic algorithm for detection of covert Bow Hunter's Syndrome.

Bow hunter's syndrome (BHS) should not be overlooked as a cause of cerebral infarction in the posterior circulation. However, covert BHS, which does not impair blood flow with simple rotation but only at certain angles, may make the diagnosis of BHS difficult. We propose a new algorithm to detect BHS or covert BHS. We recommend that BHS and covert BHS be detected by noninvasive duplex ultrasonography, which will allow for appropriate treatment.

Plantar Acceleration Time: A Novel Technique to Evaluate Arterial Flow to the Foot

Arterial duplex ultrasound (DUS) and ankle-brachial indices (ABIs) are accepted methods for assessing lower limb arterial perfusion. However, in a significant number of diabetic patients, medial wall calcification often precludes an ABI measurement. Direct, noninvasive duplex imaging of the pedal arch in the setting of peripheral arterial disease (PAD) has not been well evaluated. Although plantar arch interrogation is new to vascular ultrasound, imaging the plantar arteries appears to be a reliable angiographic technique for critical limb ischemia. We sought to define the utility of Plantar Acceleration Time as a surrogate for ABIs. Patients undergoing DUS including Plantar Acceleration Time for suspicion of PAD were retrospectively reviewed in a prospective database over a 1-year period. Two hundred fifty nondiabetic patients (499 limbs) with documented ABI were studied. Plantar Acceleration Time was calculated (milliseconds [msec]) in each limb in the lateral plantar artery. Statistical analyses were performed using linear regression and analysis of variance testing using Microsoft Excel database (version 2016; Microsoft Corp, Redmond, WA). Patients were then grouped into 4 classes based on their clinical symptoms and ABI. Plantar Acceleration Time was similarly grouped into 4 distinct classes and correlated with the clinical and ABI classes. Plantar Acceleration Time correlated significantly with ABI (P<0.001). There were significant differences in Plantar Acceleration Times between each class based on ABI and clinical presentation (P<0.001 for each): Class 1 Plantar Acceleration Times 89.9±15.5msec; Class 2, 152.3±28.4msec; Class 3, 209.8±25.5msec, and Class 4, 270.2±35.3msec. Plantar Acceleration Time demonstrates a high correlation with ABI in patients with compressible arteries. Based on our results we propose the following categories of Plantar Acceleration Time, which appear to correlate with both clinical and ABI findings. ABI of 0.90-1.3 correlates with a Plantar Acceleration Time of 0-120msec, ABI of 0.69-0.89 correlates with a Plantar Acceleration Time of 121-180msec, ABI of 0.40-0.68 correlates with a Plantar Acceleration Time of 181-224msec, and an ABI of 0.00-0.39 correlates with a Plantar Acceleration Time of greater than 225msec. Further studies are ongoing to confirm whether Plantar Acceleration Time may be a suitable substitute to ABIs in patients with noncompressible arteries that preclude meaningful ABIs and gives more information regarding targeted angiosome perfusion to the foot.

Bedside Duplex Ultrasonography Identifies Multiple Pseudoaneurysms in a Penetrating Extremity Trauma

A 14-year-old boy sustained an accidental self-inflected stab wound to the calf injuring both the posterior and anterior tibial arteries. On physical examination, pedal pulses were palpable and no obvious sign of arterial injury was identified. It was only after noninvasive duplex ultrasonography that multiple pseudoaneurysms were identified. The patient was taken to the operating room where reversed saphenous vein interposition grafts were used to repair both injuries. Therefore, use of bedside vascular duplex ultrasonography has the ability to expedite patient care.

Innovative Arterial Duplex Examination: A Guide to Evaluate Flow in the Foot Using Pedal Acceleration Time

Evaluation of the pedal arteries has not been well evaluated by noninvasive duplex ultrasound. It offers an alternative approach that directly studies the angiosome supply of the foot. The goal of this article is to describe the technique, protocol, and criteria to properly evaluate the pedal arteries of the foot with noninvasive duplex ultrasound.

Prevalence of venous thromboembolism after lung surgery in China: a single-centre, prospective cohort study involving patients undergoing lung resections without perioperative venous thromboembolism prophylaxis†.

Venous thromboembolism (VTE) is a common postoperative complication. Previous studies have shown that the incidence of VTE after major thoracic surgery ranges from 2.3% to 15%. However, there have been no such data from China so far. To evaluate the incidence of postoperative VTE, we conducted a single-centre, prospective cohort study. Patients who underwent lung resections between July 2016 and March 2017 were enrolled in this study. None of the patients received any prophylaxis perioperatively. All patients were screened for deep venous thrombosis (DVT) using non-invasive duplex lower-extremity ultrasonography 30 days before surgery and within 30 days after surgery and before discharge. Chest tomography, pulmonary embolism protocol was carried out if patients had one of the following conditions: (i) typical symptoms of pulmonary embolism, (ii) high Caprini score (≥9 points) and (iii) newly diagnosed postoperative DVT. Two hundred and sixty-two patients undergoing lung surgery were enrolled, including 115 benign and 147 malignant disease cases. The procedures included 84 sublobar lung resections, 161 lobectomies, 5 pneumonectomies and 12 mixed procedures. The overall postoperative incidence of VTE was 11.5% (30 of 262). Twenty-four patients were diagnosed with DVT (80.0%) and 6 with DVT + pulmonary embolism (20.0%). None of the patients diagnosed with VTE had obvious symptoms of VTE. The median time for VTE detection was 5 days postoperatively. The incidence of VTE was 7.0% in patients with benign lung diseases and 15.0% in those with malignant lung diseases (P < 0.05). Using the Caprini risk assessment model, 63 cases were scored as low risk, 179 as moderate risk and 20 as high risk, and each group had an incidence of postoperative VTE of 0%, 12.3% (22 of 179) and 40.0% (8 of 20), respectively (P < 0.05). In patients with lung cancer, 98% were moderate or high risk, and only 3 patients were scored in the low risk category. The incidence of VTE in patients at moderate risk and high risk was 12.0% and 36.8%, respectively, while it was 0 in low-risk patients. The following conclusions were drawn: (i) the overall incidence of postoperative VTE after lung surgery without VTE prophylaxis is substantial; (ii) lower-extremity ultrasonography was helpful in detecting asymptomatic DVT in symptomatic or high-risk patients; and (iii) VTE prophylaxis should be considered as a mandatory part of perioperative care. ChiCTR-EOC-17010577.

Comparison of ultrasound scan blood flow measurement versus other forms of surveillance in the thrombosis rate of hemodialysis access: A systemic review and meta-analysis.

The benefit of access flow surveillance in preventing vascular access thrombosis and failure remains controversial, as many randomized clinical trials (RCTs) have failed to demonstrate consistent results. The aim of this study was to perform a meta-analysis including newly published RCTs with a subgroup analysis for arteriovenous fistulas (AVFs) and arteriovenous grafts (AVGs). A systematic review of the available literature was performed according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses. An electronic search was conducted using the MEDLINE, EMBASE, and Cochrane Library databases of RCTs conducted from 1970 to 2017 that involved access flow surveillance. As a result, 9 RCTs met our criteria. The control group was defined by indirect and various surveillance methods such as dynamic venous pressure measurement and physical examination. Conversely, the interventional group was defined as a noninvasive duplex ultrasound scan (USS) or ultrasound dilution that directly measured the flow of vascular access. The studies included 990 patients comprising 658 native AVFs and 332 AVGs. The prevalence of diabetes was 29.3%and 30.5% in the interventional and control groups, respectively. The estimated overall pooled risk ratio (RR) of thrombosis was 0.782 [95% confidence interval (95% CI), 0.553-1.107; P = .17], favoring interventional group, although this was not statistically significant. In the subgroup analysis, the pooled RR of thrombosis was .562 (95% CI, 0.346-0.915; P = .02) for AVFs, which significantly favored the interventional group. Conversely, the pooled RR for AVGs was 1.104 (95% CI, 0.672-1.816; P = .70). The surveillance method to measure access flow through USS showed a significant benefit for reducing thrombosis in AVFs. The result encourages adherence to the current guidelines for AVFs. However, no benefit was found regarding AVGs. Recent guidelines with a "one-size-fits-all" approach may be revised to a "tailored-to-risk" approach.

Incidence of postoperative venous thromboembolism after thoracic surgery and its characteristic: a single center, prospective cohort study

Objective: To evaluate the incidence of postoperative venous thromboembolism (VTE) after thoracic surgery and its characteristic. Methods: This was a single-center, prospective cohort study. Patients undergoing major thoracic surgeries between July 2016 and March 2017 at Department of Thoracic Surgery, Beijing Chaoyang Hospital Affiliated to Capital Medical University were enrolled in this study. Besides the routine examination, all patients were screened for deep venous thrombosis (DVT) by using noninvasive duplex lower-extremity ultrasonography after surgery. CT pulmonary angiography (CTPA) was carried out if patients had one of the following conditions including typical symptoms of PE, high Caprini score (>9 points) or new diagnosed postoperative DVT. Caprini risk assessment model was used to detect high risk patients. No patients received any prophylaxis of VTE before surgery. Further data was analyzed for identifying the incidence of postoperative VTE. The t-test, χ2 test or Wilcoxon rank-sum test was used to analyze the quantitative data and classification data, respectively. Results: Totally 345 patients who undergoing major thoracic surgery were enrolled in this study including 145 benign diseases and 200 malignant diseases.There were 207 male and 138 female, aging from 15 to 85 years. Surgery procedures included 285 lung surgeries, 27 esophagectomies, 22 mediastinal surgeries and 11 other procedures. The overall incidence of VTE was 13.9% (48 of 345) after major thoracic surgery including 39 patients with newly diagnosed DVT (81.2%), 1 patient with PE (2.1%) and 8 patients with DVT+ PE (16.7%). The median time of VTE detected was 4.5 days postoperative. There were 89.6% (43/48) VTE cases diagnosed in 1 week. The incidence of VTE was 9.0% in patients with benign diseases, while 17.5% in malignant diseases (χ2=5.112, P<0.05). The incidence of VTE in patients with pulmonary diseases was 12.6%, among that, in patients with lung cancer and benign lung diseases was 16.4% and 7.5 % (χ2=4.946, P<0.05), respectively. Regarding to Caprini risk assessment model, the incidence of VTE in low risk patients, moderate risk patients (Caprini score 5 to 8 points)and high risk patients(≥9 points)were 0(0/77), 15.2%(33/217) and 29.4%(15/51), respectively(Z=-12.166, P<0.05). In patients with lung cancer, 98.2% of patients were moderate risk or high risk; only 3 cases scored low risk. The incidence of VTE in moderate risk and high risk patients was 13.4%(18/134) and 32.1%(9/28), respectively, while it was 0(0/3) in low risk patients. Conclusions: The overall incidence of VTE after major thoracic surgeries is 13.9%, and the incidence of VTE after lung cancer surgeries was 16.4%. Most of the VTE cases occurr within one week after the surgery. Caprini risk assessment model can identify high risk patients effectively.

Externally Delivered Focused Ultrasoundfor Renal Denervation.

The aim of this study was to assess clinical safety and efficacy outcomes of renal denervation executed by an externally delivered, completely noninvasive focused therapeutic ultrasound device. Renal denervation has emerged as a potential treatment approach for resistant hypertension. Sixty-nine subjects received renal denervation with externally delivered focused ultrasound via the KonaMedical Surround Sound System. This approach was investigated across 3 consecutive studies to optimize targeting, tracking, and dosing. In the third study, treatments were performed in a completely noninvasive way using duplex ultrasound image guidance to target the therapy. Short- and long-term safety and efficacy were evaluated through use of clinical assessments, magnetic resonance imaging scans prior to and 3 and 24 weeks after renal denervation, and, in cases in which a targeting catheter was used to facilitate targeting, fluoroscopic angiography withcontrast. All patients tolerated renal denervation using externally delivered focused ultrasound. Office blood pressure (BP) decreased by 24.6 ± 27.6/9.0 ± 15.0 mmHg (from baseline BP of 180.0 ± 18.5/97.7 ± 13.7 mmHg) in 69 patients after 6 months and 23.8 ± 24.1/10.3 ± 13.1 mmHg in 64 patients with complete 1-year follow-up. The response rate (BPdecrease >10 mmHg) was 75% after 6 months and 77% after 1 year. The most common adverse event was post-treatment back pain, which was reported in 32 of 69 patients and resolved within 72 h in most cases. No intervention-related adverse events involving motor or sensory deficits were reported. Renal function was not altered, and vascular safety was established by magnetic resonance imaging (all patients), fluoroscopic angiography (n= 48), andoptical coherence tomography (n= 5). Using externally delivered focused ultrasound and noninvasive duplex ultrasound, image-guided targeting was associated with substantial BP reduction without any major safety signals. Further randomized, sham-controlled trials will be needed to validate this unique approach.

Renal Artery Stenosis - are there Patients who Benefit from Intervention?

Atherosclerotic renal artery stenosis (ARAS) is one of the most relevant long-term complications of atherosclerotic disease. It is associated both with hypertension and increased renal and cardiovascular risk and overall mortality. Diagnostic modalities include non-invasive duplex ultrasound, dynamic magnetic resonance angiography (MRA) and computer tomography angiography (CTA) and are confirmed by using invasive renal angiography. Percutaneous revascularization of renal artery stenosis has been studied in various clinical trials. With regard to hypertension, several case series could show a clinical response to revascularization. However, the majority of randomized clinical trials could not confirm the correlation between intervention and the improvement of hypertension, kidney function, cardiovascular events, and mortality. Based on this predication the crucial tool in the treatment of ARAS is an optimal medical therapy, including statins, antihypertensive agents and platelet inhibition. Today the core point is to select subgroups and appropriate indications for better outcomes and avoiding unnecessary procedures very carefully. Therefore in patients with typical manifestations of ARAS including resistant or malignant hypertension, progressive decline of renal function, flash pulmonary edema or angina, renal artery intervention remains a sensible therapeutic option - after hemodynamic testing prior to revascularization. In the future further trials targeting patients who fulfill rational selection criteria need to be undertaken to confirm the efficacy of revascularization.

Rare Cause of Cephalalgia in a Young Woman - a Case Report

Abstract Background: Young adults meeting hypertension diagnostic criteria have a lower prevalence of a hypertension diagnosis. Headache is a rather common symptom among young people. Fibromuscular dysplasia (FMD) is an idiopathic, segmental, nonatherosclerotic and noninflammatory disease of the muscular tunica of arterial walls, leading to stenosis of small and medium-sized arteries. Fibromuscular dysplasia is much more common than previously thought and is a treatable cause of secondary hypertension. Case presentation: We present the case of an 18 y.o. young woman, with headache and high blood pressure. “White coat hypertension” was suspected. Clinical history with abrupt onset and increasingly difficult to treat hypertension especially in women, were suggestive for renal artery stenosis. Renal ultrasound and digital subtraction angiography confirmed the aspect of FMD. Sequential percutaneous renal artery angioplasty was later performed with improved evolution both from the clinical point of view and controlled blood pressure below 140/90 mmHg with minimal antihypertensive regimen. Angio CT exam of neck and brain arteries was performed, no other FMD typical lesions were identified. Conclusions: Medical treatment is first indicated for the hypertensive patient. In this particular case percutaneous renal artery angioplasty showed significant improvement in reduction of antihypertensive treatment in a young patient with secondary hypertension. Further monitoring and management of this patient will include blood pressure measurements at 3-month intervals and renal function measurements annual, as well as non-invasive duplex ultrasonography at 12-month intervals, follow-up is indefinite. It remains challenging whether the patient can be medically managed on antihypertensive medication alone.

Discrepancy Between Duplex Sonography and Digital Subtraction Angiography When Investigating Extra- and Intracranial Ulcerated Plaque

Noninvasive color-coded duplex sonography has become a good, convenient, and reproducible screening tool for the general population when studying cerebral hemodynamics and atherosclerotic disease. Digital subtraction angiography (DSA) is still the gold standard for the diagnosis of carotid stenosis, although other noninvasive imaging tools are also available. At present, ultrasound scanning, followed by confirmatory DSA, is a cost-effective way to survey patients suspected of suffering from cerebral arterial stenosis. We report two patients who had cerebral ischemic symptoms due to high-grade stenosis of either the cervical internal carotid artery (ICA) or the middle cerebral artery (MCA), combined with an ulcerated plaque. Ultrasonographic Doppler analysis identified high-grade stenotic lesions as marked elevations in the turbulent flow of the cervical ICA in one patient and of the middle cerebral artery in the other patient. Subsequently, huge plaque ulceration was found by color B-mode scanning of the patient with cervical ICA stenosis. However, DSA was able to demonstrate only a mild–moderate degree of stenosis associated with the lesions. High-grade stenotic lesions of the ICA and the middle cerebral artery were reconfirmed by computed tomography angiography and magnetic resonance angiography. An atheromatous plaque with ulceration is believed to be the cause of this discrepancy between ultrasonography and DSA.

Revaskularisation der Nierenarterienstenose: State of the Art

Atherosclerotic renal artery stenoses (aRAS) are often associated with an aorto-iliac type of peripheral occlusive artery disease and may result in deterioration of blood pressure control, chronic kidney disease and myocardial dysfunction. Stenting of aRAS has almost replaced surgical revascularisation. However, the benefit of endovascular treatment of aRAS was challenged by the results of the STAR and ASTRAL trials demonstrating similar outcomes for revascularisation and conservative treatment. Due to severe limitations in trial design, the study results can only be applied to a small proportion of the affected patient population. A clinical benefit of renal stenting can only be expected if the indication for endovascular procedure was correct, in particular if the hemodynamic relevance of the lesion was verified by non-invasive (duplex) or invasive (pressure gradient) methods. The known predictors (pulse pressure > 50 ± 10 mmHg, high diastolic blood pressure, elevated BNP levels, renal insufficiency) for clinical success are often not sufficiently implemented in the decision-making process. Unquestioned by international guidelines is the indication for revascularisation of aRAS of a single functioning kidneys, severe bilateral lesions, resistant hypertension, worsening of renal function, and in each kind of severe RAS of non-atherosclerotic nature.

Comparison of Non-Invasive Imaging Modalities Digital Subtraction Angiography (DSA), Duplex ultrasound (DUS), CT Angiography (CTA) and MR Angiography (MRA) in Defining Carotid Artery Stenosis and Anatomic Risk in the Setting of Carotid Artery Stenting

Comparison of Non-Invasive Imaging Modalities Digital Subtraction Angiography (DSA), Duplex ultrasound (DUS), CT Angiography (CTA) and MR Angiography (MRA) in Defining Carotid Artery Stenosis and Anatomic Risk in the Setting of Carotid Artery Stenting

Bilateral Superficial Temporal Artery Aneurysms

Aneurysms of the superficial temporal artery are rare and most often traumatic in origin. In this case study we present an extremely rare occurrence of bilateral nontraumatic superficial temporal artery aneurysms. Spontaneous bilateral superficial temporal artery aneurysms have not been previously reported. The patient was a 49-year-old woman who presented to our outpatient vascular lab with pulsating masses noted over bilateral temporal regions. Duplex ultrasound revealed a 2.3 mm right and 4.5 mm left temporal artery aneurysm. The aneurysms were subsequently resected and the patient recovered without incident. Non-invasive duplex ultrasound is an effective method in identifying these rare aneurysms. A literature search revealed few published cases of non-traumatic STAs and of these cases none involved bilateral vessels.

Coronary blood flow responses to physiological stress in humans

Animal reports suggest that reflex activation of cardiac sympathetic nerves can evoke coronary vasoconstriction. Conversely, physiological stress may induce coronary vasodilation to meet an increased metabolic demand. Whether the sympathetic nervous system can modulate coronary vasomotor tone in response to stress in humans is unclear. Coronary blood velocity (CBV), an index of coronary blood flow, can be measured in humans by noninvasive duplex ultrasound. We studied 11 healthy volunteers and measured beat-by-beat changes in CBV, blood pressure, and heart rate during 1) static handgrip for 20 s at 10% and 70% of maximal voluntary contraction; 2) lower body negative pressure at -10 and -30 mmHg for 3 min each; 3) cold pressor test for 90 s; and 4) hypoxia (10% O(2)), hyperoxia (100% O(2)), and hypercapnia (5% CO(2)) for 5 min each. At the higher level of handgrip, mean blood pressure increased (P < 0.001), whereas CBV did not change [P = not significant (NS)]. In addition, during lower body negative pressure, CBV decreased (P < 0.02; and P < 0.01, for -10 and -30 mmHg, respectively), whereas blood pressure did not change (P = NS). The dissociation between the responses of CBV and blood pressure to handgrip and lower body negative pressure is consistent with coronary vasoconstriction. During hypoxia, CBV increased (P < 0.02) and decreased during hyperoxia (P < 0.01), although blood pressure did not change (P = NS), suggesting coronary vasodilation during hypoxia and vasoconstriction during hyperoxia. In contrast, concordant increases in CBV and blood pressure were noted during the cold pressor test, and hypercapnia had no effects on either parameter. Thus the physiological stress known to be associated with sympathetic activation can produce coronary vasoconstriction in humans. Contrasting responses were noted during systemic hypoxia and hyperoxia where mechanisms independent of autonomic influences appear to dominate the vascular end-organ effects.

Renal artery stenting with noninvasive duplex ultrasound follow‐up: 3‐year results from the RENAISSANCE renal stent trial

The multicenter, single-arm RENAISSANCE trial evaluated outcomes in patients with progressive atherosclerotic renal artery stenosis (ARAS) treated with the Express Renal Premounted Stent System (Boston Scientific, Natick, MA). Renal artery stenting may prevent the morbidity and mortality of surgical revascularization and high restenosis rates of percutaneous renal angioplasty (PTRA). Renal artery duplex ultrasonography (DUS) offers an alternative to traditional invasive poststenting angiographic surveillance, though concordance with angiography for in-stent restenosis has yet to be validated independently. RENAISSANCE enrolled 100 patients (117 lesions) with de novo or restenotic ostial atherosclerotic lesions <or=15 mm long in vessels >or=4.0 and <or=7.0 mm diameter with diameter stenosis >or=70%. The primary endpoint, 9-month binary restenosis, was compared to an objective performance criterion (OPC) of 40% for published PTRA results. Follow-up was conducted through 3 years. Technical and procedural success was both 99%. Follow-up angiography, triggered clinically or by ultrasonography, revealed 21.3% binary restenosis at 9 months, which was superior to the OPC (P < 0.0001). Concordance between ultrasonography and angiography for detection of binary restenosis at 9 months was 87%. Peak systolic velocity and renal-to-aortic ratio were both significantly improved compared to baseline at 9 months and 2 years. The major adverse event (defined as device- or procedure-related death, target lesion revascularization or significant embolic event) rate was 10.5% at 9 months and 20.9% at 3 years. RENAISSANCE demonstrates that renal artery stenting is superior to the prespecified OPC at 9 months, and also shows that DUS can accurately identify in-stent restenosis.

The Influence of Routine Duplex Scanning Surveillance on Outcome after Percutaneous Iliac Angioplasty and Stenting

Purpose We sought to determine the utility of noninvasive color-flow duplex imaging (CDI) in the detection of iliac artery stenoses or occlusions and correlate the findings of long-term color flow duplex surveillance (CFDS) to clinical outcome after percutaneous iliac interventions. Methods All patients undergoing percutaneous iliac angioplasty and stenting are prospectively entered in a surveillance protocol with CFDS and ankle-brachial indices (ABIs) performed within 6 weeks, 6 months, 12 months, and every year thereafter. Preprocedural ABI and peak systolic velocity (PSV) values were compared with postprocedural values with the Student t-test. Kaplan-Meier life-table analysis was used to estimate the patency rates. Results During the last 4 years, 80 patients with 112 treated iliac systems fulfilled the study criteria. A total of 68 patients (84%) had claudication, 8 (10%) had pain at rest, and 5 (6%) had a nonhealing ulcer or gangrene. The procedural success rate was 96.4%. Comparison of ABIs and PSV values before and after iliac intervention was statistically significant ( p &lt; 0.0001). Duplex scan allowed the detection and/or monitoring of abnormal velocities in 14 treated iliac arteries. Four cases (3.5%) required reintervention on previously treated iliac arteries for symptomatic restenosis and/or disease progression. Late stent occlusions were correctly identified in two cases. Primary patency, assisted primary patency, and secondary patency rates were 77%, 94%, and 96% at 4 years, respectively. Conclusion CFDS allows the detection of iliac artery stenoses and is a useful tool to identify restenosis after intervention. Because of the overall excellent patency rates observed with iliac angioplasty and stenting, CFDS surveillance in the absence of symptoms may not always be necessary and its long-term use should be individualized.