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3.8 Prophylaxis for rheumatic fever

Prevention of rheumatic heart disease should preferably target the first attack of acute rheumatic fever. Antibiotic treatment of group A Streptococcus infection throat is key in primary prevention. Echocardiographic screening in combination with secondary antibiotic prophylaxis in children with evidence of latent rheumatic heart disease is currently investigated to reduce its prevalence in endemic regions.91 In patients with established rheumatic heart disease, secondary long-term prophylaxis against rheumatic fever is recommended: benzathine benzyl penicillin 1.2 MUI every 3 to 4 weeks over 10 years. Lifelong prophylaxis should be considered in high-risk patients according to the severity of VHD and exposure to group A Streptococcus.9295

4 Aortic regurgitation

Aortic regurgitation can be caused by primary disease of the aortic valve cusps and/or abnormalities of the aortic root and ascending aortic geometry. Degenerative tricuspid and bicuspid aortic regurgitation are the most common aetiologies in high-income countries, accounting for approximately two-thirds of the underlying aetiology of aortic regurgitation in the EURObservational Registry Programme Valvular Heart Disease II registry.1 Other causes include infective and rheumatic endocarditis. Acute severe aortic regurgitation is mostly caused by infective endocarditis, and less frequently by aortic dissection.

4.1 Evaluation

4.1.1 Echocardiography Echocardiography is the key examination used to describe valve anatomy, quantify aortic regurgitation, evaluate its mechanisms, define the morphology of the aorta, and determine the feasibility of valvesparing aortic surgery or valve repair.96,97 Identification of the mechanism follows the same principle such as for mitral regurgitation: normal cusps but insufficient coaptation due to dilatation of the aortic root with central jet (type 1), cusp prolapse with eccentric jet (type 2), or retraction with poor cusp tissue quality and large central or eccentric jet (type 3).96 Quantification of aortic regurgitation follows an integrated approach considering qualitative, semi-quantitative, and quantitative parameters24,98 (Table 5). New parameters obtained by 3D echocardiography and two-dimensional (2D) strain imaging as LV global longitudinal strain may be useful, particularly in patients with borderline LVEF where they may help in the decision for surgery.99 Measurement of the aortic root and ascending aorta in 2D is performed at four levels: annulus, sinuses of Valsalva, sinotubular junction, and tubular ascending aorta.100,101 Measurements are performed in the parasternal long-axis view from leading edge to leading edge at end diastole, except for the aortic annulus, which is measured in mid systole. As it will have surgical consequences, it is important to differentiate three phenotypes of the ascending aorta: aortic root aneurysms (sinuses of Valsalva >45 mm), tubular ascending aneurysm (sinuses of Valsalva <4045 mm), and isolated aortic regurgitation (all aortic diameters <40 mm). The calculation of indexed values to account for body size has been suggested,102 in particular in patients with small stature. Anatomy of the aortic valve cusps and its suitability for valve repair should be provided by preoperative TOE if aortic valve repair or a valve-sparing surgery of the aortic root is considered. Intraoperative evaluation of the surgical result by TOE is mandatory in patients undergoing aortic valve preservation or repair.

4.1.2 Computed tomography and cardiac magnetic resonance CMR should be used to quantify the regurgitant fraction when echocardiographic measurements are equivocal or discordant with clinical findings. In patients with aortic dilatation, CCT is recommended to assess the maximum diameter at four levels, as in echocardiography. CMR can be used for follow-up, but indication for surgery should preferably be based on CCT measurements. Different methods of aortic measurements have been reported. To improve reproducibility, it is recommended to measure diameters using the inner-inneredge technique at end diastole on the strictly transverse plane by double oblique reconstruction perpendicular to the axis of blood flow of the corresponding segment. Maximum root diameter should be taken from sinus-to-sinus diameter rather than sinus-tocommissure diameter, as it correlates more closely to long-axis leading-edge-to-leading-edge echo maximum diameters.103,104

4.2 Indications for intervention

Acute aortic regurgitation may require urgent surgery. It is mainly caused by infective endocarditis and aortic dissection but may also occur after blunt chest trauma and iatrogenic complications during catheter-based cardiac interventions. Specific guidelines deal with

Table 5 Echocardiographic criteria for the definition of severe aortic valve regurgitation

Qualitative Valve morphology Abnormal/flail/large coaptation

defect

Colour flow regurgitant jet areaa Large in central jets, variable in

eccentric jets

CW signal of regurgitant jet Dense Other Holodiastolic flow reversal in

descending aorta (EDV >20 cm/s)

Semiquantitative Vena contracta width (mm) >6 Pressure half-timeb (ms) <200 Quantitative EROA (mm2) >_30 Regurgitant volume (mL/beat) >_60 Enlargement of cardiac chambers LV dilatation CW = continuous wave; EDV = end-diastolic velocity; EROA = effective regurgitant orifice area; LV = left ventricle/left ventricular. aAt a Nyquist limit of 5060 cm/s. bPressure half-time is shortened with increasing LV diastolic pressure, vasodilator therapy, and in patients with a dilated compliant aorta, or lengthened in chronic aortic regurgitation. Adapted from Lancellotti P et al. Recommendations for the echocardiographic assessment of native valvular regurgitation: an executive summary from the European Association of Cardiovascular Imaging. Eur Heart J Cardiovasc Imaging 2013;14:611644. Copyright (2013) by permission of Oxford University Press on behalf of the European Society of Cardiology. ESC/EACTS 2021

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