Aortic Stenosis- Causes, Clinical Features And Treatment

Causes of Aortic Stenosis

• Congenital bicuspid aortic valve—compensural fusion.
• Arthritis of the heart
• Acquired valve fibrosis and calcification.
• The most frequent cause, acquired degenerative calcific process, results in immovable cusps. 

Pathophysiology of Aortic Stenosis

Systolic pressure overload in the left ventricle, which results from pressure grading in the aorta and left ventricle, induces left ventricular hypertrophy to restore stress and sustain cardiac output. Myocardial ischemia may result from an increase in the oxygen demand on the heart. The left ventricle's hypertrophy is insufficient to normalize the stress due to a load mismatch. 

Ineffective cardiac output results from this, which also causes a decrease in ventricular contractility and left ventricular dysfunction and failure. As aortic stenosis advances, the CO cannot increase with exertion and eventually becomes insufficient even at rest. There will be increased left ventricular end diastolic pressure. The left atrium will not be able to empty the left ventricle, leading to an increase in left atrial pressure. There will be back pressure and pulmonary congestion, which can result in pulmonary edema. 

Clinical Features of Aortic Stenosis

Up until decompensation, the patient is asymptomatic. Left ventricular failure may be the source of the patient's dyspnea. When a patient has both increased oxygen demand and left ventricular hypertrophy, they may experience angina. Additionally, there is less cardiac output during exertion and insufficient coronary perfusion.  In addition to experiencing syncope, the patient may also experience arrhythmias.
The natural history of death for ten-year-old patients with symptoms is 80–90%. Up until decompensation, the patient is asymptomatic.

Also Read: The Thoracic Anatomy

Investigations

ECG: Lateral leads show tall R waves. T wave inversion and ST depression are possible. This suggests a pattern of strain. Although the chest x-ray appears normal, there is cardiomegaly and pulmonary congestion failures.  A color flow Doppler is used in an echo for confirmation analysis.  Left ventricular size, valve area, and aortic gradient. Patients who are older than 40 will undergo coronary angiography.

Aha Guidelines

Intervention

A patient who is symptomatic and has a low or intermittent surgical risk due to severe aortic stenosis. Asymptomatic individuals with LV function less than 50% and significant stenosis. Severe AS while left with intact LV function. LVEF > 50% yet a drop in blood pressure or reduced capacity to tolerate exercise.
In individuals undergoing concurrent surgeries such as CABG, moderate to severe AS. These patients also require interventions since the reserves are insufficient. In individuals undergoing concurrent surgeries such as CABG, moderate to severe AS. The treatment can be administered surgically or non-surgically. TAVI (transcatheter aortic valve implantation) and balloon aortic valvotomy, which are performed on youngsters, are non-surgical possibilities.

Also Read: Pleura And Mediastinum 

Tavi For Aortic Stenosis

Indication 

Severe AS symptoms and unaffordable high surgical risk, with a predicted longer post-TAVI survival period (12 months). For patients who have a higher surgical risk, it serves as an alternative to surgery.
• Porcelain ascending aorta is another sign.
• Severe thoracic wall deformation at birth.
• In the previous three months, there was a recent MI.
• Severe pulmonary dysfunction is present.
• Thrombus apical.

Approaches

Advanced device in left ventricle between purse string sutures; Accesses left ventricle through apex of heart through a tiny left anterolateral thoracotomy incision;  Transapical (retrograde).
Lowers chance of calcium displacement. Transluminal (antegrade): This direct approach via the femoral, subclavian, and aortic arteries is typically recommended in patients with a prior history of heart surgery.
Contraindication: Aortic and peripheral aortic disease.

Also Read: Rapid Acquisition Of Key Concepts- Cardiothoracic And Vascular Surgery

Treatment

In pediatric patients, percutaneous aortic balloon valvotomy has a place.  Adults with few or no roles. Aortic stenosis is unrelated to aortic valve repair. Replacement of the aortic valve is the gold standard of care. A median sternotomy must be used as the method. Cardioplegia in CPB. 

Proximally, the aorta cross is clamped and opened. Replace the diseased valve with a prosthetic valve. The surgical death rate for elective repairs is between 2 and 3%.

Also Read: Knowing Venous Diseases and How to Treat Them

Hope you found this blog helpful for your Cardiothoracic and Vascular Surgery preparation. For more informative and interesting posts like these, keep reading PrepLadder’s blogs.