Ans. b > a (Aortic valve replacement > Medical Management) (Ref: ACC/AHA guidelines; European Cardiology Society Guidelines: http:// circ. ahajountals.org/ content/ 122/17/ 1734.full.pdf+html; Braunwald's Heart Disease: 9/e p1474)The patient in question has asymptomatic aortic stenosis but develops symptoms on exercise (abnormal/positive exercise test). Also the presence of mean pressure gradient of 60mm Hg put this patient into the category of 'Very Severe Aortic Stenosis' or 'Critical Aortic Stenosis'.Optimal management of asymptomatic severe Aortic Stenosis continues to be a source of ongoing clinical controversy. Surgical Aortic Valve Replacement and Watchful waiting with frequent reassessments (observation), both continue to be legitimate though debatable treatment options. Since the patient in question has 'Very Severe AS' and 'Abnormal Stress Testing' he should be considered for surgical intervention in the form of Aortic Valve Replacement (AVR).50-year-old patient with Asymptomatic Severe Aortic StenosisPositive Exercise Stress TestMean Pressure Gradient > 60 mm HgSymptoms during exercise such as dyspnea, angina, and syncope or near syncope constitute positive criteria indicating an abnormal stress test in patients with asymptomatic aortic stenosis.Mean pressure gradient >60 mm Hg and or aortic valve area < 0.6 cm2 and /or aortic jet velocity >5.0 m per second is classified as 'Extremely Severe Aortic Stenosis' (Critical Aortic Stenosis)Severe aortic stenosis with an abnormal response to exercise is considered a Class lIb indication for aortic valve replacement according to the ACC/AHA Guidelines.' Severe aortic stenosis with an abnormal response to exercise is considered a Class IC indication for aortic valve replacement according to European Cardiology Society Guidelines (ECS Guidelines)''Extremely severe aortic stenosis (mean gradient > 60 mm Hg) is considered a class lIb indication for aortic valve replacement according to the ACC/AHA Guidelines.' Indications of AVR in Asymptomatic Severe Aortic StenosisClass IClass lIb* Patients undergoing cardiac surgery for other indications (Coronary artery bypass graft surgery or aortic surgery)* Left ventricular ejection fraction <_50 %* Abnormal hemodynamic response to exercise (Symptoms or asymptomatic hypotension)* High probability of rapid progression (Age, Calcification, Concomitant CAD)* Asymptomatic 'very severe AS'