Aortic Stenosis Treatment & Management

The only definitive treatment for aortic stenosis is aortic valve replacement. The development of symptoms due to aortic stenosis provides a clear indication for replacement. For patients who are not candidates for aortic replacement, percutaneous aortic balloon valvuloplasty may provide some symptom relief.^[4]

Medical treatment (such as diuretic therapy) in aortic stenosis may provide temporary symptom relief but is generally not effective long term.

In truly asymptomatic patients with severe aortic stenosis, the issue of valve replacement is less clear.

Prehospital and emergency department management is focused on acute exacerbations of the symptoms of aortic stenosis. As always, assess and address airway, breathing, and circulation. If the patient is in cardiopulmonary arrest, perform resuscitation according to the recommendations of the AHA in their Advanced Cardiac Life Support guidelines. In patients with acute symptoms, hospital admission, telemetry/intensive care unit admission, and cardiology consultation all should be considered.

A patient presenting with uncontrolled heart failure should be treated supportively with oxygen, cardiac and oximetry monitoring, intravenous access, loop diuretics, nitrates (remembering the potential nitrate sensitivity of patients with aortic stenosis), morphine (as needed and tolerated), and noninvasive or invasive ventilatory support (as indicated). Patients with severe heart failure due to aortic stenosis that is resistant to medical management should be considered for urgent surgery.

A patient presenting with angina pectoris requires monitoring and studies as listed above. Measures should be taken to relieve the chest discomfort. This may include the administration of nitrates, oxygen, and morphine. However, nitroglycerin-induced syncope occurs more often in patients with aortic stenosis than in those without aortic stenosis. This information should be obtained through the history at presentation.

Syncope in the face of aortic stenosis should be assessed and treated as in any patient presenting with a syncopal episode.

Atrial fibrillation in the setting of aortic stenosis is considered a medical emergency, and sinus rhythm should be restored urgently in patients who are hemodynamically unstable. Associated symptoms also should be treated urgently.

Percutaneous balloon valvuloplasty is used as a palliative measure in critically ill adult patients who are not surgical candidates or as a bridge to aortic valve replacement in critically ill patients. The high rate of restenosis and the absence of a mortality benefit preclude its use as a definitive treatment method in adults with severe aortic stenosis.

Valvuloplasty can be considered in cases of severe heart failure or cardiogenic shock for the following patients:

• Patients with other comorbid conditions with a very short life expectancy
• Patients who refuse surgery
• Patients with heart failure who need an urgent, major noncardiac surgical procedure
• Pregnant patients with critical aortic stenosis

In critically ill patients, the mortality rate associated with the procedure is 3-7%. Another 6% develop serious complications, including perforation, myocardial infarction, and severe aortic regurgitation.

In children, adolescents, and young adults with congenital aortic stenosis, percutaneous balloon valvuloplasty carries a mortality risk of 1% and may be an alternative to surgical valvotomy. The risk of causing significant aortic regurgitation is 10%. Although exercise restriction is sometimes recommended to avoid the risk of sudden unexpected death for some patients with congenital aortic stenosis, a recent study by Brown et al suggests that sudden unexpected death is extremely rare following balloon valvuloplasty, and the study found no beneficial effect for exercise restriction after the procedure is performed.^[18]

The best results from valvuloplasty are obtained in the patients with a commissural bicuspid aortic valve, in whom a 60-70% reduction in gradient and a 60% increase in the AVA can be expected.

Restenosis is common, particularly in patients with unicuspid valves or with valves affected by severe dysplasia (>60% at 6 mo, virtually 100% at 2 y). However, repeat procedures have been shown to provide a median survival rate of approximately 3 years and to maintain clinical improvement.^[19]

The recommendations of the ACC/AHA 2006 valvular heart disease guidelines for aortic valve replacement in patients with valvular aortic stenosis are summarized below, in Table 5.^[11] In most adults with symptomatic, severe aortic stenosis, aortic valve replacement is the surgical treatment of choice. If concomitant coronary disease is present, aortic valve replacement and coronary artery bypass graft (CABG) should be performed simultaneously.

Table 5. Recommendations for Aortic Valve Replacement in Aortic Stenosis (Open Table in a new window)

Successful aortic valve replacement produces substantial clinical and hemodynamic improvement in patients with aortic stenosis, including octogenarians. Aortic valve replacement should be performed in all symptomatic patients with severe aortic stenosis, regardless of LV function, as survival is better with surgical treatment than with medical treatment.

Aortic valve replacement is also recommended in asymptomatic patients with severe aortic stenosis and LV dysfunction. Improvement in EF invariably occurs over the following 6 months, and increased LV mass tends to decrease within 18 months postoperatively.

Bioprosthetic and mechanical valves

The choice of prosthesis is determined by the anticipated longevity of the patient and his/her ability to tolerate anticoagulation.^[20]

Stassano et al found that bioprosthetic aortic valves were significantly less durable than were mechanical valves. In a prospective, randomized study of 310 patients aged 55-70 years, followup at 13 years showed that valve failures and reoperations were more frequent in the bioprosthesis group than in the mechanical prosthesis group. However, there were no differences between the 2 types of valves regarding the rates of survival, thromboembolism, bleeding, endocarditis, and major adverse prosthesis-related events.^[21]

The surgical mortality risk in patients with normal LV systolic function and no other comorbid conditions is less than 5%. Risk factors for increased operative mortality include the following:

• High New York Heart Association (NYHA) class (25-30% mortality in patients with class IV)
• Preoperative LV systolic dysfunction
• Older age
• Associated aortic regurgitation

Overall, the 5-year survival rate in all adults after aortic valve replacement is 80-94%, and the 10-year survival rate is 68-89%. Risk factors for late death include the following:

• High preoperative NYHA class
• LV systolic dysfunction
• Preoperative ventricular arrhythmias
• Concomitant aortic regurgitation
• Atrial fibrillation
• Coronary artery disease, particularly a history of myocardial infarction

Ross procedure

The Ross procedure is another option in young patients as an initial procedure or for reoperation after prior valvotomy. In this procedure, the patient's own pulmonary valve and main pulmonary artery are transplanted to the aortic position, with reimplantation of coronary arteries. A homograft is placed in the pulmonary position. Its durability may be better than tissue valves. However, the Ross procedure is technically demanding and results at different centers have been mixed.

Percutaneous transcatheter valve replacement

Many patients with severe aortic stenosis and coexisting conditions are not candidates for surgical replacement of the aortic valve. Studies have suggested that percutaneous transcatheter aortic-valve replacement (TAVR) with a balloon-expandable bovine pericardial valve is a less invasive option for these high-risk patients.^{[22, 23]} In a study comparing TAVR (via a transfemoral or a transapical approach) and surgical replacement in patients who were candidates for valve replacement but considered to be high risk, survival at 1 year was similar for both procedures.^[24] However, important differences in periprocedural risks were observed; major vascular complications and stroke were more frequent with TAVR, whereas major bleeding and new-onset atrial fibrillation were more frequent with surgical valve replacement.

A comprehensive literature review by Daneault evaluated the incidence of stroke after surgical and transcatheter treatment for aortic stenosis. The risk of stroke for the general population after aortic valve replacement was 1.5% (2-4% in higher risk and elderly patients). The rate after transcatheter treatment was 1.5-6%. This review shows a trend for more strokes in the transcatheter group.^[25]

The medical treatment options are limited in symptomatic patients with aortic stenosis who are not candidates for surgery. In patients with pulmonary congestion, cautious use of digitalis, diuretics, and angiotensin-converting enzyme (ACE) inhibitors might attempted, whereas beta-blockers might be used if the predominant symptom is angina. In any case, excessive decrease in preload or systemic arterial blood pressure should be avoided.

Vasodilators may be used for heart failure and for hypertension but should also be employed with extreme caution to avoid critically reducing preload or systemic arterial blood pressure in a patient with significant aortic stenosis.

Severe hypertension is frequently seen in the elderly patient with aortic stenosis and should be treated, because it causes an additional increase in vascular afterload. Treatment should follow the guidelines set out in the Seventh Report of the Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure.^[26] Reducing the blood pressure to normal levels is advisable, but hypotension must be avoided.

Endocarditis prophylaxis

Antibiotic prophylaxis for the prevention of bacterial endocarditis is no longer recommended in patients with valvular aortic stenosis.^[27]

Activity

Patients with mild aortic stenosis can lead a normal life. In cases of moderate aortic stenosis, moderate to severe physical exertion and competitive sports should be avoided.

Although small, observational studies have suggested that statin use can reduce aortic valve leaflet calcification and delay the progression of aortic stenosis severity,^[28] 3 randomized, double-blind, placebo controlled trials of almost 2200 patients showed that intensive lipid-lowering therapy does not halt the progression of calcific aortic stenosis or induce its regression.^{[29, 30, 31]}

Possible complications of aortic stenosis include the following:

• Sudden cardiac death
• Heart failure
• Conduction defects
• Calcific embolization

Consultation with a cardiologist or cardiothoracic surgeon is appropriate.

The frequency of the follow-up visits in asymptomatic patients is determined by the severity of aortic stenosis and by the presence of comorbid conditions.

In patients with mild aortic stenosis, yearly history and physical examination and an echocardiogram every 3-5 years are appropriate.

Patients with moderate or severe aortic stenosis should be examined twice yearly and whenever they develop symptoms that are potentially attributable to aortic stenosis.

In patients with moderate aortic stenosis, echocardiograms should be performed every 2 years, whereas in asymptomatic patients with severe aortic stenosis, yearly echocardiograms are recommended.

Following aortic valve replacement, every patient should undergo echocardiographic examination after recovery. Thereafter, an examination is recommended whenever new symptoms develop that are attributable to a potential valvular dysfunction.

Patients with mechanical valves should receive lifelong anticoagulation with warfarin and should undergo periodic screening of their anticoagulation status.

The 2011 ACCF/AHA/HRS Focused Update on the Management of Patients With Atrial Fibrillation (Update on Dabigatran) from the ACC Foundation (ACCF)/AHA/Heart Rhythm Society (HRS) states that the new anticoagulant dabigatran is useful as an alternative to warfarin in patients with atrial fibrillation. Dabigatran has not been studied in patients with atrial fibrillation and valvular heart disease and is not approved by the FDA for this population.^[32]