MORBIDITY & MORTALITY : Among symptomatic patients with moderate-to-severe AS treated medically, mortality rates from the onset of symptoms were approximately 25% at 1 year and 50% at 2 years. More than 50% of deaths were sudden. Death in general, including sudden death, occurs primarily in symptomatic patients.
Asymptomatic patients, even with critical AS, have an excellent prognosis regarding survival, with an expected death rate of less than 1% per year; only 4% of sudden cardiac deaths in severe AS occur in asymptomatic patients.
Although the obstruction tends to progress more rapidly in patients with degenerative calcific AV disease than in those with congenital or rheumatic disease, predicting the rate of progression in individual patients is not possible. Therefore, careful clinical follow-up is mandatory in all patients with moderate-to-severe AS. Catheterization and echocardiographic studies suggest that the valve area may decline 0.1-0.3 cm2 per year; the systolic pressure gradient across the valve can increase by as much as 10-15 mm Hg per year. A higher rate of progression is observed in elderly patients with coronary artery disease (CAD) and chronic renal insufficiency.
Medical Care: The primary management of symptomatic patients with valvular AS is interventional. Medical treatment essentially is reserved for patients who have complications of AS such as heart failure, infective endocarditis, or arrhythmias.
" Digitalis can be used as an inotropic agent and also to control the ventricular rate in cases with atrial fibrillation. Diuretics may be used for pulmonary congestive symptoms, and vasodilators may be used for heart failure and for hypertension. Both classes of agents should be used with caution to avoid critically reducing preload in a patient with significant AS and a hypertrophic noncompliant LV. The same precaution also is valid for beta-blockers and calcium channel blockers.
" Endocarditis prophylaxis is recommended in all patients regardless of the etiology or the patient's age and surgical status. The risk of valve-ring abscess is highest of all of the valve lesions.
" Recently, several small observational studies suggested that HMG-CoA reductase inhibitor use can reduce AV leaflet calcification and delay the progression of AS severity. Some of these studies attributed this effect to the consequence of lowering of serum LDL levels; in others, the effect was independent of serum LDL levels. Although these retrospective studies are promising for a potential role of these drugs in the management of calcific AV disease, no data are currently available from prospective, randomized, placebo-controlled trials to recommend their routine use. In similar observational studies, use of ACE inhibitors was associated with slower calcium accumulation in AV; however, no hemodynamic benefit was seen during the same period. A recent randomized clinical trial of atorvastatin versus placebo showed no difference in AVA or pressure gradients.
Surgical Care: The primary management of symptomatic patients with valvular AS is interventional. The timing of intervention is determined by the severity of the stenosis, the age of the patient, and the presence of symptoms. In asymptomatic patients with severe AS, follow-up is needed every 6 months. The natural history suggests that patients with a mean gradient of less than 25 mm Hg have a 20% chance of requiring intervention in 15 years. Overall, 40% of those in the medically treated group require intervention in 15 years, although in certain cases, progression to severe AS may be faster.
The age of patients undergoing AVR is rising steadily because the incidence of calcific AS increases as the age of the population increases. The percentage of patients older than 70 years who undergo AVR and have functional class III or IV is very high. Early detection and close follow-up of patients with AS, along with a low threshold for the intervention decision, reduces the operative risk and improves the duration and quality of life. Once symptoms develop, intervention is needed.
" Percutaneous balloon valvuloplasty was introduced approximately 10 years ago. Generally, it is used as a palliative measure in critically ill patients who are not surgical candidates or as a bridge in critically ill patients before they undergo AVR.
o ACC/AHA recommendations for aortic balloon valvotomy in adults with AS are summarized in Table 5. In cases of congenital AS without calcified unicuspid or bicuspid AV in children, adolescents, and young adults, percutaneous balloon valvuloplasty is an accepted alternative to surgical valvotomy and carries a risk of 1%, but its value is limited in adults with calcific AS. The high rate of restenosis and the absence of a mortality benefit preclude its use as a definitive treatment method in these cases. However, a recent study investigated the long-term outcome of balloon valvuloplasty in patients with severe AS, including repeat procedures to maintain symptom relief and survival impact. In 212 patients with severe AS who were not operative candidates, repetitive balloon valvuloplasty emerged as a viable strategy to maintain clinical improvement and provided a median survival of 3 years.
o The best results from valvuloplasty are obtained in patients with congenital commissural bicuspid AVs, where a 60-70% reduction in gradient and a 60% increase in AVA can be expected. It is recommended for patients with gradients higher than 50-60 mm Hg and/or a valve area of less than 0.5 cm2/m2, even in asymptomatic patients, because of the low risk associated with balloon valvuloplasty, the high desire for unrestricted or minimally limited lifestyle in younger populations, and the incidence of certain rare cases of sudden cardiac death. The risk rate of causing significant AR is 10%.
o 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). More than mild AR poses a contraindication for this procedure.
o Valvuloplasty also can be performed in patients with severe CHF or cardiogenic shock (1) as a bridge to valve replacement as a palliative measure, (2) for patients with other comorbid conditions with a very short life expectancy, (3) for those who refuse surgery, (4) for those with heart failure who need an urgent major noncardiac surgical procedure, or (5) in pregnant patients with critical AS.
o 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 AR.
Table 5. Recommendations for Aortic Balloon Valvotomy in Adults With Aortic Stenosis
Indication Class
A bridge to surgery in hemodynamically unstable patients IIA
who are at high risk for AVR
Palliation in patients with serious comorbid conditions IIb
Patients who require urgent noncardiac surgery IIb
As an alternative to AVR III
" Aortic valve replacement
o ACC/AHA recommendations for AV replacement in patients with valvular AS are summarized in Table 6. In most adults with calcific AS and in those patients with calcified, bicuspid, severely stenotic AVs, AVR is the surgical treatment of choice. It is recommended if hemodynamic evidence of severe obstruction and symptoms due to AS are present. It also is recommended in asymptomatic patients with LV dysfunction. AVR should be performed in all symptomatic patients with severe AS regardless of LV function. Even in the presence of LV dysfunction, survival is better with surgical treatment than with medical treatment.
o Prior to AV surgery, complete hemodynamic assessment of AS with either Doppler or catheterization is required. Assessment of LV function and MV disease also is required. If significant MR is present, the degree of regurgitation should be evaluated intraoperatively after replacement of the AV to determine the need for MV repair or replacement, unless intrinsic disease of the MV apparatus is present. Coronary angiography is needed in all patients aged 35-40 years and in those patients with risk factors for CAD.
o Successful AVR produces substantial clinical and hemodynamic improvement in patients with AS, including octogenarians. The choice of prosthesis is determined by the anticipated longevity of the patients and their ability to tolerate anticoagulation.
o Postoperatively, end-diastolic pressure and ESV drop significantly, and symptoms of elevated LA pressure and ischemia improve. Improvement in EF invariably occurs over the following 6 months, and increased LV mass tends to decrease within 18 months postoperatively.
o 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 (1) high New York Heart Association (NYHA) class (25-30% mortality in patients with class IV), (2) preoperative LV systolic dysfunction (strongest predictor of postoperative LV dysfunction), (3) age (up to 30% mortality in patients >80 y but is not a contraindication for AVR), and (4) the presence of associated AR.
o The skill level of the surgical team cannot be ignored.
o Whenever possible, AVR and coronary artery bypass graft (CABG) should be performed at the same time. The increase in operative mortality is negligible compared to AVR alone. Risk factors for late death include preoperative NYHA class and LV systolic function, preoperative ventricular arrhythmias, concomitant AR, atrial fibrillation, and CAD, particularly a history of myocardial infarction. Overall, the 5-year survival rate in all adults after AVR is 80-94%, whereas 10-year survival rate is 68-89%.
Table 6. Recommendations for Aortic Valve Replacement in Aortic Stenosis
Indication Class
Symptomatic patients with severe AS I
Patients with severe AS undergoing
coronary artery bypass surgery I
Patients with severe AS undergoing surgery on the aorta or other heart valves I
Patients with moderate AS undergoing coronary artery bypass surgery or surgery on the aorta or other heart valves IIa
Asymptomatic patients with severe AS and the following:
LV systolic dysfunction IIa
Abnormal response to exercise (eg, hypotension) IIa
Ventricular tachycardia IIb
Marked or excessive LVH (>15 mm) IIb
Valve area <0.6 cm2 IIb
Prevention of sudden death in asymptomatic patients with none of the findings listed under asymptomatic patients with severe AS III
o 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 is better than with tissue valves, and anticoagulation is not required. This procedure is technically demanding.
o Despite the proven efficacy of surgical valve replacement, it still carries high operative mortality and morbidity rates in the growing population of elderly patients with significant comorbidities. Recently, percutaneous AV replacement using the antegrade transseptal and retrograde arterial approaches has been introduced as an alternative to surgical AV replacement in a subset of patients with AS who are at high surgical risk. In the first reported human case, using the transcatheter technique with antegrade transseptal approach, a trileaflet bovine pericardial valve mounted within a balloon-expandable stent was successfully deployed with significant hemodynamic improvement. In another case, a retrograde arterial approach was successfully used because the antegrade approach was complicated by guidewire injury to the mitral valve. Although percutaneous AV replacement may be an exciting alternative to the standard surgical approach, this approach has thus far raised more questions than it has provided answers.
Activity: Patients with mild AS can lead a normal life. In cases of moderate AS, moderate-to-severe physical exertion and competitive sports should be avoided.
DRUG TREATMENT :
1. SHORT & LONG ACTING NITRATES
3. CARDIAC GLYCOSIDES
4. DIURETICS
5. DIRECT ACTING ADRENERGIC AGONISTS - DOBUTAMINE IN CHF