In stenoses classified as ischemic, the wave-free period provided a similar reduction in microvascular resistance as adenosine-mediated hyperaemia over the whole cardiac cycle. The Hybrid iFR-FFR approach has been proposed as method of minimising patient exposure to adenosine or other vasodilators. In this approach, an iFR can be measured, and stenoses with an iFR >0.93 may be deferred while those with an iFR <0.86 can be treated by revascularization. Stenoses with an iFR between 0.86-0.93 can undergo an FFR assessment to guide therapy.
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Coronary artery blockages or stenoses that limit blood flow to the heart muscle can cause angina and can be treated by stenting or bypass surgery. Relief of a stenosis by stenting aims to restore vessel patency with improvement in blood flow leading to a reduction in angina symptoms. However, if stenoses are not flow limiting, then they can be safely left alone without stenting or surgery and this help reduce patient's exposure to unnecessary procedures and potential complications. Identifying stenoses that cause flow limitation, or ischaemia, can be done in a variety of ways.
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Nonspecific inflammatory changes are present. Giant cells or other typical features of granulomatous inflammation are not found. Multiple stenoses are typically present (mean 8: range 1-25).
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Stenoses of the vascular type are often associated with unusual blood sounds resulting from turbulent flow over the narrowed blood vessel. This sound can be made audible by a stethoscope, but diagnosis is generally made or confirmed with some form of medical imaging.
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The causative organism is usually Pseudomonas aeruginosa. A rare form is laryngeal perichondritis (perichondritis laryngis). It develops suddenly due to an injury, virulent organisms or compromised immune status of the host, and also affects cartilage of the larynx. This may result in deformations and stenoses.
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Segmental arterial mediolysis (SAM) is a rare disorder of the arteries characterized by the development of aneurysms, blood clots, narrowing of the arteries (stenoses), and blood collections (hematomas) in the affected distribution. SAM most commonly affects the arteries supplying the intestines and abdominal organs.
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This process is the myocardial infarction or "heart attack". If the heart attack is not fatal, fibrous organization of the clot within the lumen ensues, covering the rupture but also producing stenosis or closure of the lumen, or over time and after repeated ruptures, resulting in a persistent, usually localized stenosis or blockage of the artery lumen. Stenoses can be slowly progressive, whereas plaque ulceration is a sudden event that occurs specifically in atheromas with thinner/weaker fibrous caps that have become "unstable". Repeated plaque ruptures, ones not resulting in total lumen closure, combined with the clot patch over the rupture and healing response to stabilize the clot is the process that produces most stenoses over time.
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Next came bypass surgery, to plumb transplanted veins, sometimes arteries, around the stenoses and more recently angioplasty, now including stents, most recently drug coated stents, to stretch the stenoses more open. Yet despite these medical advances, with success in reducing the symptoms of angina and reduced blood flow, atheroma rupture events remain the major problem and still sometimes result in sudden disability and death despite even the most rapid, massive and skilled medical and surgical intervention available anywhere today. According to some clinical trials, bypass surgery and angioplasty procedures have had at best a minimal effect, if any, on improving overall survival. Typically mortality of bypass operations is between 1 and 4%, of angioplasty between 1 and 1.5%.
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One common application of active ACG is the Transcranial Doppler test. More recently, its color version (TCCD) has been deployed. These ultrasonic procedures measure blood flow velocity within the brain's blood vessels. They are used to diagnose embolisms, stenoses and vascular constrictions, for example, in the aftermath of a subarachnoid hemorrhage.
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The predicted iFR values produced by the virtual-PCI on the iFR- pullback are closely related to those observed after PCI in the coronary vessel. This predictive capacity may provide added advantage to Interventional Cardiologists when assessing multiple coronary stenoses in a single vessel and planning the treatment approach. iFR-pullback technologies are undergoing evaluation in European centres.
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A mnemonic to remember what characteristics to look for when listening to murmurs is SCRIPT: Site, Configuration (shape), Radiation, Intensity, Pitch and quality, and Timing in the cardiac cycle. The use of two simple mnemonics may help differentiate systolic and diastolic murmurs; PASS and PAID. _Pulmonary and aortic stenoses are systolic while pulmonary and aortic insufficiency (regurgitation) are diastolic_. _Mitral and tricuspid defects are opposite.
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Abdominal pain is often most severe in areas of the bowel with stenoses. Persistent vomiting and nausea may indicate stenosis from small bowel obstruction or disease involving the stomach, pylorus, or duodenum. Although the association is greater in the context of ulcerative colitis, Crohn's disease may also be associated with primary sclerosing cholangitis, a type of inflammation of the bile ducts. Perianal discomfort may also be prominent in Crohn's disease.
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These stenoses can be more adequately identified and assessed with catheter cerebral venography and manometry. Buckling of the bilateral optic nerves with increased perineural fluid is also often noted on MRI imaging. Lumbar puncture is performed to measure the opening pressure, as well as to obtain cerebrospinal fluid (CSF) to exclude alternative diagnoses. If the opening pressure is increased, CSF may be removed for transient relief (see below).
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For more severe subglottic stenoses, Gerwat and Bryce (1974) described the first cricotracheal resection with preservation of the recurrent laryngeal nerves. Pearson and Gullane would later report their success using this procedure over the ensuing 22 years in 80 consecutive adults with benign subglottic stenosis. Impressed by the results of Gerwat and Bryce, Monnier, Savary, and Chapuis performed the first cricoid resection with primary anastomosis in a child in 1978.
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Diagnostic findings for CTEPH are: # Invasively (i.e., in the blood) measured mean pulmonary arterial pressure (mPAP) ≥25 mmHg; # Mismatched perfusion defects on lung ventilation/perfusion (V/Q) scan and specific diagnostic signs for CTEPH seen by multidetector computed tomography angiography (MDCT), magnetic resonance imaging (MRI) or conventional pulmonary cineangiography (PAG), such as ring-like stenoses, webs/slits, chronic total occlusions (pouch lesions, or tapered lesions) and tortuous lesions.
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Surveillance is performed by regularly repeating coronary angiography in the cardiac catheterization laboratory, the diagnostic test of choice. This is typically performed annually for the first five years after transplantation. Angiography in CAV characteristically demonstrates diffuse stenoses in large coronary arteries and a reduced number of smaller coronary arteries, also known as "peripheral pruning". However, because CAV frequently affects the entire length of the coronary artery, CAV may not be apparent by angiography alone.
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This range can be changed by the physician according to how closely they want to match an FFR-classification of lesions. Using this typical range, almost 60% of stenoses can be spared from needing vasodilator infusion. ADVISE-II has prospectively assessed the hybrid approach in an independent international multi-centre study which confirmed the findings of the earlier Hybrid analysis. Interim results were reported by Javier Escaned at EuroPCR, the final findings were presented at TCT 2013.
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Angiography is also commonly performed to identify vessels narrowing in patients with leg claudication or cramps, caused by reduced blood flow down the legs and to the feet; in patients with renal stenosis (which commonly causes high blood pressure) and can be used in the head to find and repair stroke. These are all done routinely through the femoral artery, but can also be performed through the brachial or axillary (arm) artery. Any stenoses found may be treated by the use of balloon angioplasty, stenting, or atherectomy.
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Laryngotracheal stenosis (Laryngo-: Glottic Stenosis; Subglottic Stenosis; Tracheal: narrowings at different levels of the windpipe) is a more accurate description for this condition when compared, for example to subglottic stenosis which technically only refers to narrowing just below vocal folds or tracheal stenosis. In babies and young children however, the subglottis is the narrowest part of the airway and most stenoses do in fact occur at this level. Subglottic stenosis is often therefore used to describe central airway narrowing in children, and laryngotracheal stenosis is more often used in adults.
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Venous sinus stenoses leading to venous hypertension appear to play a significant part in relation to raised ICP, and stenting of a transverse sinus may resolve venous hypertension, leading to improved CSF resorption, decreased ICP, cure of papilledema and other symptoms of IIH. A self-expanding metal stent is permanently deployed within the dominant transverse sinus across the stenosis under general anaesthesia. In general, people are discharged the next day. People require double antiplatelet therapy for a period of up to 3 months after the procedure and aspirin therapy for up to 1 year.
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Fearon and Cotton further investigated tracheal augmentation using thyroid cartilage (harvested from the inferior border) in African green monkeys and proved that the cricoid could be divided without inhibition of laryngeal growth. In 1976, Fearon and Cinnamond reported on 35 patients operated on using this technique between 1970 and 1976, noting that free thyroid grafts were more feasible than pedicled grafts and that costal cartilage was most suitable for repairing long segment stenoses. They also proposed that shaping anterior costal cartilage grafts with flanges might prevent them from being displaced inward into the trachea.
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These findings have been in keeping with an international collaborative study, RESOLVE, which pooled retrospective data from many centres worldwide with independent core-lab analysis of raw pressure traces. Conflicting data, when re-analysed using the clinically available iFR-algorithms produced results similar to the ADVISE- Registry and ADVISE Hybrid studies. iFR has also been compared to FFR and the resting Pd/Pa ratio in the post-coronary intervention setting. In a manner similar to FFR, iFR can be used to measure the haemodynamic change induced by stent placement and detect the impact of any residual stenoses.
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Neuroimaging, usually with computed tomography (CT/CAT) or magnetic resonance imaging (MRI), is used to exclude any mass lesions. In IIH these scans typically appear to be normal, although small or slit-like ventricles, dilatation and buckling of the optic nerve sheaths and "empty sella sign" (flattening of the pituitary gland due to increased pressure) and enlargement of Meckel's caves may be seen. An MR venogram is also performed in most cases to exclude the possibility of venous sinus stenosis/obstruction or cerebral venous sinus thrombosis. A contrast- enhanced MRV (ATECO) scan has a high detection rate for abnormal transverse sinus stenoses.
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Review of prior cross-sectional imaging or a venogram of the IVC is performed before deploying the filter to assess for potential anatomic variations, thrombi within the IVC, or areas of stenoses, as well as to estimate the diameter of the IVC. Rarely, ultrasound-guided placement is preferred in the setting of contrast allergy, chronic kidney disease, and when patient immobility is desired. The size of the IVC may affect which filter is deployed, as some (such as the Birds Nest) are approved to accommodate larger cavae. There are situations where the filter is placed above the renal veins (e.g.
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However the average or typical stenosis at which myocardial infarctions occurred were found to be less than 50%, describing plaques long considered insignificant by many. Only 14% of heart attacks occurred at locations with 75% or more stenosis, the severe stenoses previously thought by many to present the greatest danger to the individual. This research has changed the primary focus for heart attack prevention from severe narrowing to vulnerable plaque. Current clinical uses of IVUS technology include checking how to treat complex lesions before angioplasty and checking how well an intracoronary stent has been deployed within a coronary artery after angioplasty.
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Intravascular ultrasound image of a coronary artery (left), with color-coding on the right, delineating the lumen (yellow), external elastic membrane (blue) and the atherosclerotic plaque burden (green). In angiology or vascular medicine, duplex ultrasound (B Mode imaging combined with Doppler flow measurement) is used to diagnose arterial and venous disease. This is particularly important in neurology, where carotid ultrasound is used for assessing blood flow and stenoses in the carotid arteries, and transcranial Doppler is used for imaging flow in the intracerebral arteries. Intravascular ultrasound (IVUS) uses a specially designed catheter, with a miniaturized ultrasound probe attached to its distal end, which is then threaded inside a blood vessel.
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Two outcome studies, DEFINE- FLAIR and the iFR-SWEDEHEART will assess whether patient outcomes differ if stenoses are treated according to iFR or FFR classification of stenosis severity. DEFINE-FLAIR, which aims to recruit 2500 patients, will be the largest physiological study to date and will provide the first randomised data of the use of iFR and FFR in patients with both stable coronary disease and acute coronary syndromes. It will also provide the first randomised data of the clinical utility of FFR in guiding and deferring coronary intervention outside of the FAME and DEFER studies. Both DEFINE-FLAIR and iFR-SWEDEHEART have harmonised clinical endpoints which will enable combined analysis of over 4500 patients.
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During this wave-free period, the competing forces (waves) that affect coronary flow are quiescent meaning pressure and flow are linearly related as compared to the rest of the cardiac cycle. When stenoses are flow limiting, Pd and Pa pressures over the wave-free period diverge; a normal ratio is 1.0 and iFR values of below 0.90 suggest flow limitation. iFR can be calculated using dedicated consoles available for medical use and typically uses an average over 5 heart beats but can be performed using a single heart beat. iFR is measured at rest, without the need for pharmacological vasodilators or stressors and compares well to other invasive and non-invasive markers of ischemia or flow limitation.
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In contrast to conventional angiography, cardiac CT angiography does enable visualization of the vessel wall as well as plaque composition. Some of the CT derived plaque characteristics can help predict for acute coronary syndrome. In addition, because these lesions do not produce significant stenoses, they are typically not considered "critical" and/or interventionable by interventional cardiologists, even though research indicates that they are the more important lesions for producing heart attacks. The tests most commonly performed clinically with the goal of testing susceptibility to future heart attack include several medical research efforts, starting in the early to mid-1990s, using intravascular ultrasound (IVUS), thermography, near-infrared spectroscopy, careful clinical follow-up, and other methods, to predict these lesions and the individuals most prone to future heart attacks.
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The most significant impact of magnetic resonance neurography is on the evaluation of the large proximal nerve elements such as the brachial plexus (the nerves between the cervical spine and the underarm that innervate shoulder, arm and hand), the lumbosacral plexus (nerves between the lumbosacral spine and legs), the sciatic nerve in the pelvis, as well as other nerves such as the pudendal nerve that follow deep or complex courses. Neurography has also been helpful for improving image diagnosis in spine disorders. It can help identify which spinal nerve is actually irritated as a supplement to routine spinal MRI. Standard spinal MRI only demonstrates the anatomy and numerous disk bulges, bone spurs or stenoses that may or may not actually cause nerve impingement symptoms.
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