Authors

• Vlatka Rešković — University of Zagreb School of Medicine, University Hospital Centre Zagreb, Zagreb, Croatia
• Lukšić — University of Zagreb School of Medicine, University Hospital Centre Zagreb, Zagreb, Croatia

Abstract

Bicuspid aortic valve is the most common congenital heart disease, although in the narrow sense it is not considered a disease but a predisposition for its development. The range of manifestations and the time of the onset of such a disease of the aortic valve vary greatly. In our practice, patients with manifestation at an early age, and especially those with accompanying anomalies (aortic aneurysm, coarctation, membrane), are classified under of congenital heart diseases due to the fact that, as is shown herein, such patients require constant monitoring and often multiple interventions. The patient described here is a good example of a combination of congenital disorder and coronary heart disease, which is characteristic for patients with congenital heart diseases under long-term monitoring.

Keywords

bicuspid aortic valve, aortic stenosis, subaortic membrane, coronary aneurysm, aortic valve replacement

DOI

Full Text

## Introduction Bicuspid aortic valve (BAV) is the most common congenital heart disease in adults, one we encounter daily in clinical practice. Although studies show that it does not affect survival, it is an important issue because affected patients are faced with numerous complications and, as a consequence of that, frequent interventions that impact quality of life and cardiovascular outcomes. Since this is a disease of the valve but also of the aortic wall, the genetic basis of which is partially known, we are faced with an entire range of disease manifestations – from an entirely asymptomatic disease in adulthood to symptomatic disease with needing intervention in childhood. The disease affects 0.5-2.0% of the total population, is three times as common among men, and occurs familially (10% among first cousins). It is based on a valvulogenesis disorder that leads to the creation of two usually unequal leaflets; due to a disorder in fibrillin-1 synthesis the valve and the aortic wall are of poorer quality, and the changes in the valve also lead to further hemodynamic turbulence that causes additional damage. The typical BAV (type 1) occurs as a result of a fusion of the right and left coronary leaflet, with consequential anteroposterior orientation. Type 2, also known as atypical, has a right-left orientation (there is a fusion between the right and the non-coronary leaflet), and the rarest type is the result of a fusion of the left and the non-coronary leaflet. At the place where the commissures have fused there is commonly a thicker area, also known as “raphe”. Type 1 is more commonly associated with valve stenosis in adulthood, as well as the dilatation of the ascending aorta and the coarctation of the aorta, whereas type 2 is associated with earlier complications in childhood and the dilatation of both the ascending aorta and the aortic arch. The most common associated anomalies are aortopathy (more common in type 2) and the coarctation of the aorta (in 20% of all patients with BAV), whereas less common anomalies include ventricular septal defect (VSD), Ebstein’s anomaly, hypoplastic left heart syndrome, abnormal anatomy of coronary arteries, patent ductus arteriosus, atrial septal defect (ASD), and bicuspid pulmonic valve. The presentation and the clinical progression depend on the complications that have developed. Most common is aortic stenosis, a result of degeneration and calcification of the valve and usually requiring intervention in middle age. Aortic regurgitation is most commonly the result of valve prolapse, endocarditis, dilatation of the aortic root, or myxoid degeneration of the valve, and usually requires intervention in early adult age (10-40 years). Endocarditis is not common (it occurs in less than 2% of patients with BAV) but outcomes are worse in comparison with the healthy population. Regarding the complications in the aorta (aortic aneurysm, dissection, and rupture), aneurysm of the ascending aorta is very common (even up to 80%) whereas the other two complications are less frequent, but have a high rate of mortality (the incidence of dissection is 1-4% in patients with BAV, but is nine times more common than in the general population). (1, 2) Echocardiography is the primary diagnostic method. Usually only a transthoracic echocardiographic examination is sufficient for the identification of the disease and any existing complications, as well as for further monitoring. Special attention is paid to the assessment of the valve disease, the measurement of the dimensions of the ascending aorta, the progression of the valve disease, the dilatation of the aorta, and the discovery of associated anomalies, e.g. aortic coarctation. In more complicated cases or when it is impossible to assess (usually due to the amount of calcification) the number of leaflets and during preoperative preparation, it is necessary do perform transesophageal heart ultrasound, whereas monitoring aortopathy requires a computed tomography (CT) or magnetic resonance (MR) aortography. (3) The frequency of follow-up imaging examinations is usually determined individually for each patient, but should certainly be regular. There is of course no specific treatment, but conditions that can lead to complications should be treated, for example in cases of arterial hypertension, prevention of aortopathy (using beta blockers or ARBs), endocarditis prophylaxis, etc. After all, most patients will require some form of intervention in their lifetime. This will primarily mean the replacement of the valve or, in rarer cases, balloon dilatation of the valve, and the physician will consult the patient when deciding on the optimal intervention and type of valve. Of course, after the intervention these patients still require our strict supervision; the importance of this will be emphasized using the example of one case from clinical practice. ## Case report A 41-year-old man who had had a confirmed heart murmur since childhood was given an echocardiographic examination due to the angina in exertion in 2010. A transthoracic echocardiography (TTE) examination (**Figure 1**, **Figure 2**) showed ample calcification in the bicuspid aortic valve with severe aortic stenosis and preserved left ventricular systolic function (max gradient 195 mmHg, mean 122 mmHg, AVA 0.6cm2, AVA/BSA 0.3cm2/m2, EF LV 60%). Coronary angiography excluded the disease of epicardial arteries, and the patient was referred to a cardiac surgeon. After two years, in May of 2012, while waiting for the recommended cardiac surgery, the patient again sought treatment due to symptoms of heart failure. TTE showed a significant reduction in left ventricular systolic function (EF 30%, AVA 0.5cm2, max PG 137 mmHg, mean 80 mmHg, no dilatation of the ascending aorta), and coronary angiography now showed an aneurysm on the transition from the proximal into mid LAD that was 11×8 mm (**Figure 3**) in size. An emergency surgical procedure was indicated in order to replace the aortic valve, and it was decided to resolve the LAD aneurysm afterwards by putting in a stent graft in case myocardial ischemia was established. On September 11, 2012 patient underwent aortic valve replacement with ATS Medical 21 mm valve. During operation a subaortic membrane was discovered (under the left and right coronary cusp) and resected in the same operation, and decalcification of the left ventricular outflow tract and the annulus of the aortic valve was also performed. Already several days after the procedure there was improvement of the left ventricular systolic function (LVEF 55%), but with high gradients over the aortic valve (max gradient 83 mmHg) and mild aortic regurgitation. Figure 1. Extreme hypertrophy of the left ventricle in patient with severe aortic stenosis. Figure 2. Continuous-wave Doppler signal of severe aortic stenosis jet shows high velocities. Figure 3. Angiogram of the left coronary artery. Note coronary artery aneurysms. However, after the operation the patient still experienced exertion intolerance accompanied by chest pain. In October 2014, a myocardial perfusion SPECT (Single Photon Emission Computed Tomography) was performed and showed ischemia at the apex and lateral wall of the left ventricle. At the next echocardiographic examination the patient claimed his difficulties were becoming more severe. Laboratory tests showed that he had been inadequately anticoagulated for a long period of time, with hemodynamically unfavorable parameters of flow over the mechanical AV (max gradient 100 mmHg, moderate AR, intracavitary gradient 20 mmHg, EF 60%), so he was hospitalized for further testing. Since the gradients over the valve showed no significant change in comparison with early postoperative values, and since diascopy excluded valve thrombosis, a patient prosthesis mismatch (EOA/BSA=0.70) was found to be the cause of the patient’s issues. Repeated coronarography showed two tandem saccular aneurysms of up to 6 mm in the trunk, the distal trunk and ostial LAD with up to 70% stenosis, and another saccular aneurysm of mid LAD diameter of up to 8mm. A reoperation was indicated, and a double bypass grafting (LAD-LIMA, RIM-VSM) was performed along with the LV outflow tract resection and aortic root dilatation. An SJM Regent 21 mm valve (**Figure 4**) with a better hemodynamic parameters for this patient was implanted (expected gradient = 15.6±9.4, mid = 8.0±4.8, EOA = 2.0±0.7, EOA/BSA = 1.01), and the operation was performed with no complications. In later follow-up the patient reported no subjective difficulties, no chest pain, and reacting well to physical exertion. An echocardiographic examination found a wide LVOT after myectomy, concentrically hypertrophied LV, EF 60%, max gradient of 49 mmHg, mean 26 mmHg, and AVA 1.6cm2, which are satisfactory values. Figure 4. Echocardiography after coronary artery bypass grafting with dilatation of the aortic anulus, resection of the left ventricular outflow tract and implantation of the SJM Regent 21 valve. ## Discussion Based on the patient’s issues, the hemodynamic performance of the valve, and the existing pathology of coronary arteries, which was certainly at least one part of the cause of the symptoms, it was clear that another intervention was necessary. However, the decision was not easy. This is where the so-called “heart team”, composed of the patient’s cardiologist, echo sonographer, interventional cardiologist, and cardiovascular surgeon, offered ample assistance. The risk of the operation was high, the planned surgery quite extensive, and the outcome questionable because it was clear that even after myectomy it would be impossible to implant a much bigger valve, whereas the pronounced hypertrophy of myocardium, which can lead to diastolic dysfunction, could still cause difficulties and limit the patient in everyday activities. Additionally, there was the question of the “life expectancy” of the artificial ventricle and the likelihood of a third reoperation later in the patient’s life. If the vicious cycle is not severed however, the pressure overload and ischemia will lead to progressive hypertrophy and fibrosis, and later to intractable heart failure. Although the clinical course after the second operation has so far been favorable, in the long-term we are faced with monitoring the valve function, the dimensions of the ascending aorta – which is at this time not dilated, controlling the arterial pressure, prophylaxis of endocarditis, and solving all other comorbidities we expect due to aging. ## Conclusion Extensive clinical experience on the incidence of the disease and generally favorable clinical outcome must not deceive us into “losing track” of a patient with a slow disease progression or who has already undergone intervention, because this is still a young and vulnerable population with a normal life expectancy and with it good quality of life. Therefore, it is important to keep in mind all the possible complications of the disease itself as well as the complications of the interventions performed, and provide continuous supervision. This primarily applies to echocardiographic monitoring of the progression of aortic stenosis and regurgitation, monitoring of the aortic dimension, and assessment of the size and function of the left ventricle in patients that have not yet been operated on. In postoperative monitoring it is important to recognize late restenosis, progressive aortic regurgitation, and other complications (such as arrhythmia or flow disturbances). In order to optimize intervention time, the role of the heart team in specialized centers for adult congenital heart diseases is important to the entire process.

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