A genetic disorder called “Brickers-Adams-Edwards syndrome” or “X-linked hydrocephalus” has been discovered that leads to aqueductal stenosis. This disease is transmitted from mother to son. This disorder is caused by a point mutation in the gene for neural cell adhesion. Most males born with this have severe hydrocephalus, adducted thumbs, spastic motions, and intellectual problems. Females with this defect may have adducted thumbs or subnormal intelligence.

Bacterial meningitis can also result in gliotic blockage of the aqueduct. In utero infection or infection during infancy could both result in glial cell build up to make an obstruction.

In cases of aqueductal stenosis caused by tumor compression, a brain tumor in the region of the midbrain forms. More specific anatomically, a tumor forms in the pineal region which is dorsal to the midbrain and is level with the aqueduct of Sylvius. As the tumor grows and expands, it compresses the aqueduct to eventually obstruct it.

Because the shunt systems are too expensive for most people in developing countries, such people often die without getting a shunt. Worse, the rate of revision in shunt systems adds to the cost of shunting many times. Looking at this point, a study compares shunt systems and highlights the role of low-cost shunt systems in most of the developing countries. It compares the Chhabra shunt system to shunt systems from developed countries.

Frisch & Simonsen (2016) carried out a very large scale study in Denmark, which compared the incidence of meatal stenosis in Muslim males (mostly circumcised) with the incidence of meatal stenosis in ethnic Danish males (mostly non-circumcised). The risk of meatal stenosis in circumcised males was found to be as much 3.7 times higher than in the intact, non-circumcised males.

The cause of hydrocephalus is not known with certainty and is probably multifactorial. It may be caused by impaired cerebrospinal fluid (CSF) flow, reabsorption, or excessive CSF production.

- Obstruction to CSF flow hinders the free passage of cerebrospinal fluid through the ventricular system and subarachnoid space (e.g., stenosis of the cerebral aqueduct or obstruction of the interventricular foramina) secondary to tumors, hemorrhages, infections or congenital malformations) and can cause increases in central nervous system pressure.

- Hydrocephalus can also be caused by overproduction of cerebrospinal fluid (relative obstruction) (e.g., Choroid plexus papilloma, villous hypertrophy).

- Bilateral ureteric obstruction is a rare, but reported, cause of hydrocephalus.

Based on its underlying mechanisms, hydrocephalus can be classified into communicating and non-communicating (obstructive). Both forms can be either congenital or acquired.

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 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

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.

Penile Revascularization is a specialized vascular-surgical treatment option for Erectile Dysfunction. The 2009 International Consultation on Sexual Dysfunctions recommended that revascularization be limited to nonsmoker, nondiabetic men younger than 55 years of age with isolated stenosis of the internal pudendal artery with absence of venous leak.

Patients with persistent erectile dysfunction after revascularization may benefit from repeat penile duplex ultrasound and pelvic angiography to evalauate the status of the bypass graft and to exclude the presence of a PASS as the cause. The prevalence of an aberrant obturator artery arising from the inferior epigastric artery is approximately 10.5%. If an aberrant obturator artery is visualized arising from the inferior epigastric artery prior to surgical penile revascularization, consideration should be given toward using an alternative source artery or to embolization to avoid the creation of a Penile Artery Shunt Syndrome encountered in this described case.

Numerous studies over a long period of time clearly indicate that male circumcision contributes to the development of urethral stricture. Among circumcised males, reported incidence of meatal stricture varies. Griffiths "et al". (1985) reported an incidence of 2.8 percent. Sörensen & Sörensen (1988) reported 0 percent. Cathcart "et al". (2006) reported an incidence of 0.55 percent. Yegane "et al". (2006) reported an incidence of 0.9 percent. Van Howe (2006) reported an incidence of 7.29 percent. In Van Howe's study, all cases of meatal stenosis were among circumcised boys. Simforoosh "et al". (2010) reported an incidence of 0.55 percent. According to Emedicine (2016), the incidence of meatal stenosis runs from 9 to 20 percent. Frisch & Simonsen (2016) placed the incidence at 5 to 20 percent of circumcised boys.

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.

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.

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.

Pyloric stenosis seems to be multifactorial, with some genetic and some environmental components. It is four times more likely to occur in males, and is also more common in the first born. Rarely, infantile pyloric stenosis can occur as an autosomal dominant condition.

It is uncertain whether it is a congenital anatomic narrowing or a functional hypertrophy of the pyloric sphincter muscle.

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.

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.

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

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.

Percutaneous Coil Embolization of the aberrant obturator artery was performed. Arterial flow rapidly improved through the left dorsal penile artery, and brisk opacification was seen through to the glans penis. Post-procedure, the patient experienced an immediate improvement in erectile function.

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

Males are more commonly affected than females, with firstborn males affected about four times as often, and there is a genetic predisposition for the disease. It is commonly associated with people of Scandinavian ancestry, and has multifactorial inheritance patterns. Pyloric stenosis is more common in Caucasians than Hispanics, Blacks, or Asians. The incidence is 2.4 per 1000 live births in Caucasians, 1.8 in Hispanics, 0.7 in Blacks, and 0.6 in Asians. It is also less common amongst children of mixed race parents. Caucasian male babies with blood type B or O are more likely than other types to be affected.

Infants exposed to erythromycin are at increased risk for developing hypertrophic pyloric stenosis, especially when the drug is taken around two weeks of life and possibly in late pregnancy and through breastmilk in the first two weeks of life.

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 treated early, that is, before the onset of pulmonary hypertension, a good outcome is possible in patients with Shone’s syndrome. However, other surgical methods can be employed depending upon the patient’s medical background. The single most important determinant of poor outcome during the surgical management of patients with Shone's syndrome is the degree of involvement of the mitral valve and the presence of secondary pulmonary hypertension.

Laryngotracheal stenosis refers to abnormal narrowing of the central air passageways. This can occur at the level of the larynx, trachea, carina or main bronchi.

In a small number of patients narrowing may be present in more than one anatomical location.