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Deep Learning Technology: Sebastian Arnold, Betty van Aken, Paul Grundmann, Felix A. Gers and Alexander Löser. Learning Contextualized Document Representations for Healthcare Answer Retrieval. The Web Conference 2020 (WWW'20)
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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.
Laryngotracheal stenosis is an umbrella term for a wide and heterogeneous group of very rare conditions. The population incidence of adult post-intubation laryngotracheal stenosis which is the commonest benign sub-type of this condition is approximately 1 in 200,000 adults per year. The main causes of adult laryngotracheal stenosis are:
The epidemiology of pulmonary valve stenosis can be summed up by the congenital aspect which is the majority of cases, in broad terms PVS is rare in the general population.
The treatment of choice is percutaneous balloon valvuloplasty and is done when a resting peak gradient is seen to be >60mm Hg or a mean >40mm Hg is observed.
The resulting syndrome depends on the structure affected.
Examples of vascular stenotic lesions include:
- Intermittent claudication (peripheral artery stenosis)
- Angina (coronary artery stenosis)
- Carotid artery stenosis which predispose to (strokes and transient ischaemic episodes)
- Renal artery stenosis
The types of stenoses in heart valves are:
- Pulmonary valve stenosis, which is the thickening of the pulmonary valve, therefore causing narrowing
- Mitral valve stenosis, which is the thickening of the mitral valve (of the left heart), therefore causing narrowing
- Tricuspid valve stenosis, which is the thickening of the tricuspid valve (of the right heart), therefore causing narrowing
- Aortic valve stenosis, which is the thickening of the aortic valve, therefore causing narrowing
Stenoses/strictures of other bodily structures/organs include:
- Pyloric stenosis (gastric outflow obstruction)
- Lumbar, cervical or thoracic spinal stenosis
- Subglottic stenosis (SGS)
- Tracheal stenosis
- Obstructive jaundice (biliary tract stenosis)
- Bowel obstruction
- Phimosis
- Non-communicating hydrocephalus
- Stenosing tenosynovitis
- Atherosclerosis
- Esophageal stricture
- Achalasia
- Prinzmetal angina
- Vaginal stenosis
Stenosis of the pulmonary artery is a condition where the pulmonary artery is subject to an abnormal constriction (or stenosis). Peripheral pulmonary artery stenosis may occur as an isolated event or in association with Alagille syndrome, Berardinelli-Seip congenital lipodystrophy type 1, Costello syndrome, Keutel syndrome, nasodigitoacoustic syndrome (Keipert syndrome), Noonan syndrome or Williams syndrome.
It should not be confused with a pulmonary valve stenosis, which is in the heart, but can have similar hemodynamic effects. Both stenosis of the pulmonary artery and pulmonary valve stenosis are causes of pulmonic stenosis.
In some cases it is treated with surgery.
If untreated, severe symptomatic aortic stenosis carries a poor prognosis with a 2-year mortality rate of 50-60% and a 3-year survival rate of less than 30%. Prognosis after aortic valve replacement for people who are younger than 65 is about five years less than that of the general population; for people older than 65 it is about the same.
A stenosis is an abnormal narrowing in a blood vessel or other tubular organ or structure. It is also sometimes called a stricture (as in urethral stricture).
Stricture as a term is usually used when narrowing is caused by contraction of smooth muscle (e.g., achalasia, prinzmetal angina); stenosis is usually used when narrowing is caused by lesion that reduces the space of lumen (e.g., atherosclerosis). The term coarctation is another synonym, but is commonly used only in the context of aortic coarctation.
Restenosis is the recurrence of stenosis after a procedure. The term is from Ancient Greek στενός, "narrow".
When pulmonic stenosis (PS) is present, resistance to blood flow causes right ventricular hypertrophy. If right ventricular failure develops, right atrial pressure will increase, and this may result in a persistent opening of the foramen ovale, shunting of unoxygenated blood from the right atrium into the left atrium, and systemic cyanosis. If pulmonary stenosis is severe, congestive heart failure occurs, and systemic venous engorgement will be noted. An associated defect such as a patent ductus arteriosus partially compensates for the obstruction by shunting blood from the left ventricle to the aorta then back to the pulmonary artery (as a result of the higher pressure in the left ventricle) and back into the lungs.
Approximately 2% of people over the age of 65, 3% of people over age 75, and 4% percent of people over age 85 have aortic valve stenosis. The prevalence is increasing with the aging population in North America and Europe.
Risk factors known to influence disease progression of AS include lifestyle habits similar to those of coronary artery disease such as hypertension, advanced age, being male, hyperlipidemia, diabetes mellitus, cigarette smoking, metabolic syndrome, and end-stage kidney disease.
Pulmonary vein stenosis is a rare cardiovascular disorder. It is recognized as being the stenosis of one or more of the four pulmonary veins that return blood from the lungs to the left atrium of the heart. In congenital cases, it is associated with poor prognosis and high mortality rate. In some people, pulmonary vein stenosis occurs after pulmonary vein ablation for the treatment of atrial fibrillation. Some recent research has indicated that it may be genetically linked in congenital cases.
In peripheral procedures, rates are still high. A 2003 study of selective and systematic stenting for limb-threatening ischemia reported restenosis rates at 1 year follow-up in 32.3% of selective stenting patients and 34.7% of systematic stenting patients.
The 2006 SIROCCO trial compared the sirolimus drug-eluting stent with a bare nitinol stent for atherosclerotic lesions of the superficial femoral artery, reporting restenosis at 2 year follow-up was 22.9% and 21.1%, respectively.
A 2009 study compared bare nitinol stents with percutaneous transluminal angioplasty (PTA) in superficial femoral artery disease. At 1 year follow-up, restenosis was reported in 34.4% of stented patients versus 61.1% of PTA patients.
Subglottic stenosis is a congenital or acquired narrowing of the subglottic airway. Although it is relatively rare, it is the third most common congenital airway problem (after laryngomalacia and vocal cord paralysis). Subglottic stenosis can present as a life-threatening airway emergency. It is imperative that the otolaryngologist be an expert at dealing with the diagnosis and management of this disorder. Subglottic stenosis can affect both children and adults.
Subglottic stenosis can be of three forms, namely congenital subglottic stenosis, idiopathic subglottic stenosis (ISS) and acquired subglottic stenosis. As the name suggests, congenital subglottic stenosis is a birth defect. Idiopathic subglottic stenosis is a narrowing of the airway due to an unknown cause. Acquired subglottic stenosis generally follows as an after-effect of airway intubation, and in extremely rare cases as a result of gastroesophageal reflux disease (GERD).
Subglottic stenosis is graded according to the Cotton-Meyer classification system from one to four based on the severity of the blockage.
Grade 1 – <50% obstruction
Grade 2 – 51–70% obstruction
Grade 3 – 71–99% obstruction
Grade 4 – no detectable lumen
Treatments to alleviate the symptoms of subglottic stenosis includes a daily dose of steroids such as prednisone, which reduces the inflammation of the area for better breathing. Other medications such as Methotrexate is also being tested by patients but results are pending.
Congenital stenosis of vena cava is a congenital anomaly in which the superior vena cava or inferior vena cava has an aberrant interruption or coarctation.
In some cases, it can be asymptomatic, and in other cases it can lead to fluid accumulation and cardiopulmonary collapse.
In terms of treatment for pulmonary valve stenosis, valve replacement or surgical repair (depending upon whether the stenosis is in the valve or vessel) may be indicated. If the valve stenosis is of congenital origin, balloon valvuloplasty is another option, depending on the case.
Valves made from animal or human tissue (are used for valve replacement), in adults metal valves can be used.
Hypertension is defined when a patient's blood pressure in the arm exceeds 140/90 mmHg under normal conditions. This is a severe problem for the heart and can cause many other complications. In a study of 120 coarctation repair recipients done in Groningen, The Netherlands, twenty-nine patients (25%) experienced hypertension in the later years of life due to the repair. While hypertension has many different factors that lead to this stage of blood pressure, people who have had a coarctation repair — regardless of the age at which the operation was performed — are at much higher risk than the general public of hypertension later in life. Undetected chronic hypertension can lead to sudden death among coarctation repair patients, at higher rates as time progresses.
Angioplasty is a procedure done to dilate an abnormally narrow section of a blood vessel to allow better blood flow. This is done in a cardiac catheterization laboratory. Typically taking two to three hours, the procedure may take longer but usually patients are able to leave the hospital the same day. After a coarctation repair 20-60% of infant patients may experience reoccurring stenosis at the site of the original operation. This can be fixed by either another coarctectomy.
Coronary artery disease (CAD) is a major issue for patients who have undergone a coarctation repair. Many years after the procedure is done, heart disease not only has an increased chance of affecting coarctation patients, but also progresses through the levels of severity at an alarmingly increased rate. In a study conducted by Mare Cohen, MD, et al., one fourth of the patients who experienced a coarctation died of heart disease, some at a relatively young age.
Clinical criteria are used in most studies when defining recurrence of coarctation (recoarctation) when blood pressure is at a difference of >20 mmHg between the lower and upper limbs. This procedure is most common in infant patients and is uncommon in adult patients. In a study conducted by Koller et al., 10.8% of infant patients underwent recoarctations at less than two years of age while another 3.1% of older children received a recoarctation.
People who have had a coarctation of the aorta are likely to have bicuspid aortic valve disease. Between 20% and 85% of patients are affected with this disease. Bicuspid aortic valve disease is a big contributor to cardiac failure, which in turn makes up roughly 20% of late deaths to coarctation patients.
In cardiac procedures, balloon angioplasty has been associated with a high incidence of restenosis, with rates ranging from 25% to 50%, and the majority of these patients need further angioplasty within 6 months.
A 2010 study in India comparing coronary drug-eluting stents (DES) with coronary bare-metal stents (BMS) reported that restenosis developed in 23.1% of DES patients vs 48.8% in BMS patients, and female sex was found to be a statistically significant risk factor for developing restenosis.
The following table includes the main types of valvular stenosis and regurgitation. Major types of valvular heart disease not included in the table include mitral valve prolapse, rheumatic heart disease and endocarditis.
Leaving the hospital after a coarctation procedure is only one step in a lifelong process. Just because the coarctation was fixed does not mean that the patient is cured. It is extremely important to visit the cardiologist on a regular basis. Depending on the severity of the patient's condition, which is evaluated on a case-by-case level, visiting a cardiologist can be a once a year surveillance check up. Keeping a regular schedule of appointments with a cardiologist after a coarctation procedure is complete helps increase the chances of survivability for the patients.
A right ventricular outflow tract obstruction (RVOTO) may be due to a defect in the pulmonic valve, the supravalvar region, the infundibulum, or the pulmonary artery.
- Pulmonary atresia
- Pulmonary valve stenosis
- Hypoplastic right heart syndrome
- Tetralogy of Fallot
A left ventricular outflow tract obstruction (LVOTO) may be due to a defect in the aortic valve, or a defect located at the subvalvar or supravalvar level.
- Aortic valve stenosis
- Supravalvar aortic stenosis
- Coarctation of the aorta
- Hypoplastic left heart syndrome
Supravalvular aortic stenosis is associated with genetic damage at the Elastin gene locus on chromosome 7q11.23. Fluorescent in situ hybridisation techniques have revealed that 96% of patients with Williams syndrome, where supravalvular aortic stenosis is characteristic, have a hemizygous deletion of the Elastin gene. Further studies have shown that patients with less extensive deletions featuring the Elastin gene also tend to develop supravalvular aortic stenosis
Supravalvular aortic stenosis is a congenital obstructive narrowing of the aorta just above the aortic valve. It is often associated with other cardiovascular anomalies and is one of the characteristic findings of Williams syndrome. The diagnosis can be made by echocardiography or MRI.
Tricuspid valve stenosis itself usually doesn't require treatment. If stenosis is mild, monitoring the condition closely suffices. However, severe stenosis, or damage to other valves in the heart, may require surgical repair or replacement.
The treatment is usually by surgery (tricuspid valve replacement) or percutaneous balloon valvuloplasty. The resultant tricuspid regurgitation from percutaneous treatment is better tolerated than the insufficiency occurring during mitral valvuloplasty.
The evaluation of individuals with valvular heart disease who are or wish to become pregnant is a difficult issue. Issues that have to be addressed include the risks during pregnancy to the mother and the developing fetus by the presence of maternal valvular heart disease as an intercurrent disease in pregnancy.
Normal physiological changes during pregnancy require, on average, a 50% increase in circulating blood volume that is accompanied by an increase in cardiac output that usually peaks between the midportion of the second and third trimesters. The increased cardiac output is due to an increase in the stroke volume, and a small increase in heart rate, averaging 10 to 20 beats per minute. Additionally uterine circulation and endogenous hormones cause systemic vascular resistance to decrease and a disproportionately lowering of diastolic blood pressure causes a wide pulse pressure. Inferior vena caval obstruction from a gravid uterus in the supine position can result in an abrupt decrease in cardiac preload, which leads to hypotension with weakness and lightheadedness. During labor and delivery cardiac output increases more in part due to the associated anxiety and pain, as well as due to uterine contractions which will cause an increases in systolic and diastolic blood pressure.
Valvular heart lesions associated with high maternal and fetal risk during pregnancy include:
1. Severe aortic stenosis with or without symptoms
2. Aortic regurgitation with NYHA functional class III-IV symptoms
3. Mitral stenosis with NYHA functional class II-IV symptoms
4. Mitral regurgitation with NYHA functional class III-IV symptoms
5. Aortic and/or mitral valve disease resulting in severe pulmonary hypertension (pulmonary pressure greater than 75% of systemic pressures)
6. Aortic and/or mitral valve disease with severe LV dysfunction (EF less than 0.40)
7. Mechanical prosthetic valve requiring anticoagulation
8. Marfan syndrome with or without aortic regurgitation
In individuals who require an artificial heart valve, consideration must be made for deterioration of the valve over time (for bioprosthetic valves) versus the risks of blood clotting in pregnancy with mechanical valves with the resultant need of drugs in pregnancy in the form of anticoagulation.