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............................................................................................................................................................................. surgery, follow-up should be continued at 36-month intervals. Surgery may be considered in asymptomatic patients with significant LV dilatation (LVEDD >65 mm), and with progressive enlargement in the size of LV or progressive decrease of LVEF during follow-up. Patient’s BNP levels could be of potential interest as a predictor of outcomes (particularly symptom onset and deterioration of LV function) and may be helpful in the follow-up of asymptomatic patients.149

Patients with mild-to-moderate aortic regurgitation can be seen on a yearly basis and echocardiography performed every 2 years. If the ascending aorta is dilated (>40 mm), it is recommended to systematically perform CCT or CMR. Follow-up assessment of the aortic dimension should be performed using echocardiography and/ or CMR. Any increase >3 mm should be validated by CCT angiography/CMR and compared with baseline data. After repair of the ascending aorta, Marfan patients remain at risk for dissection of the residual aorta and lifelong regular multidisciplinary follow-up at an expert centre is required.

4.5 Special patient populations

If aortic regurgitation requiring surgery is associated with severe primary and secondary mitral regurgitation, both should be treated during the same operation. In patients with moderate aortic regurgitation who undergo CABG or mitral valve surgery, the decision to treat the aortic valve is controversial, as data show that progression of moderate aortic regurgitation is very slow in patients without aortic dilation.150 The Heart Team should decide based on the aetiology of aortic regurgitation, other clinical factors, the life expectancy of the patient, and the patient’s operative risk. The level of physical and sports activity in the presence of a dilated aorta remains a matter of clinical judgment in the absence of evidence. Current guidelines are very restrictive, particularly regarding isometric exercise, to avoid a catastrophic event.151 This approach is justified in the presence of connective tissue disease, but a more liberal approach is likely to be appropriate in other patients. Given the familial risk of thoracic aortic aneurysms, screening and referral for genetic testing of the patient’s first-degree relatives with appropriate imaging studies is indicated in patients with connective tissue disease. For patients with bicuspid valves, it is appropriate to have an echocardiographic screening of first-degree relatives.

5 Aortic stenosis

Aortic stenosis is the most common primary valve lesion requiring surgery or transcatheter intervention in Europe1 and North America. Its prevalence is rising rapidly as a consequence of the ageing population.2,152

5.1 Evaluation

5.1.1 Echocardiography Echocardiography is key to confirming the diagnosis and severity of aortic stenosis, assessing valve calcification, LV function and wall thickness, detecting other valve disease or aortic pathology, and providing prognostic information.43,153,154 Assessment should be undertaken when blood pressure (BP) is well controlled to avoid the confounding flow effects of increased afterload. New echocardiographic parameters, stress imaging and CCT provide important adjunctive information when severity is uncertain (Figure 3).

Current international recommendations for the echocardiographic evaluation of patients with aortic stenosis25 depend upon measurement of mean pressure gradient (the most robust parameter), peak transvalvular velocity (Vmax), and valve area. Although valve area is the theoretically ideal measurement for assessing severity, there are numerous technical limitations. Clinical decision making in discordant cases should therefore take account of additional parameters: functional status, stroke volume, Doppler velocity index,156 degree of valve calcification, LV function, the presence or absence of LV hypertrophy, flow conditions, and the adequacy of BP control.25 Low flow is arbitrarily defined by a stroke volume index (SVi) <_35 mL/m2—a threshold that is under current debate.155,157,158 The use of sex -specific thresholds has been recently proposed.159 Four broad categories can be defined: • High-gradient aortic stenosis [mean gradient >_40 mmHg, peak velocity >_4.0 m/s, valve area <_1 cm2 (or <_0.6 cm2/m2)]. Severe aortic stenosis can be assumed irrespective of LV function and flow conditions. • Low-flow, low-gradient aortic stenosis with reduced ejection fraction (mean gradient <40 mmHg, valve area <_1 cm2, LVEF <50%, SVi <_35 mL/m2). Low-dose dobutamine stress echocardiography (DSE) is recommended to distinguish between true severe and pseudo-severe aortic stenosis (increase in valve area to >1.0 cm2 with increased flow) and identify patients with no flow (or contractile) reserve.160 However, utility in elderly patients has only been evaluated in small registries.161 • Low-flow, low-gradient aortic stenosis with preserved ejection fraction (mean gradient <40 mmHg, valve area <_1 cm2, LVEF >_50%, SVi <_35 mL/m2). Typically encountered in hypertensive elderly subjects with small LV size and marked hypertrophy.157,162 This scenario may also result from conditions associated with low stroke volume (e.g. moderate/severe mitral regurgitation, severe tricuspid regurgitation, severe mitral stenosis, and large ventricular septal defect and severe RV dysfunction). Diagnosis of severe aortic stenosis is challenging and requires careful exclusion of measurement errors and other explanations for the echocardiographic findings,25 as well as the presence or absence of typical symptoms (with no other explanation), LV hypertrophy (in the absence of coexistent hypertension) or reduced LV longitudinal strain (with no other cause). CCT assessment of the degree of valve calcification provides important additional information [thresholds (Agatston units) for severe aortic stenosis: men >3000, women >1600= highly likely; men >2000, women >1200 = likely; men <1600, women <800 = unlikely].35,36,163,164 • Normal-flow, low-gradient aortic stenosis with preserved ejection fraction (mean gradient <40 mmHg, valve area <_1 cm2, LVEF>_50%, SVi >35 mL/m2). These patients usually have only moderate aortic stenosis.36,165167

5.1.2 Additional diagnostic and prognostic parameters The resting Doppler velocity index (DVI, also termed ‘dimensionless index’)—the ratio of the left ventricular outflow tract (LVOT) time- Downloaded from academic.oup.com/eurheartj/article/43/7/561/6358470 by guest on 07 October 2026