Eur J Cardiothorac Surg 2005;28:346-348
© 2005 Elsevier Science NL
Giant aneurysms of the sinuses of Valsalva and aortic regurgitation in a patient with Noonan's syndrome
Richard Purnell
a
,
*
,
Ian Williams
a
,
Ulrich Von Oppell
b
,
Andrew Wood
c
a Department of Cardiology, University Hospital of Wales, Heath Park, Cardiff, UK
b Department of Cardiothoracic Surgery, University Hospital of Wales, Heath Park, Cardiff, UK
c Department of Vascular Radiology, University Hospital of Wales, Heath Park, Cardiff, UK
Received 10 February 2005;
accepted 2 May 2005.
* Corresponding author. Address: Department of Cardiology, Morriston Hospital, Heol Maes Eglwys, Morriston, Swansea SA6 6NL, USA. Tel.: +44 1792 702222x4477; fax: +44 1792 704140. (Email: richardpurnell{at}aol.com).
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Abstract
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Noonan's syndrome is one of the commonest hereditary syndromes with cardiac involvement. We report a rare presentation of this syndrome, associated with giant aneurysms of the left and non-coronary sinuses of Valsalva, resulting in symptomatic aortic valve regurgitation. The patient's clinical investigations and operative management are presented. Histological examination of aortic tissues offers insight into the pathogenesis of these complications.
Key Words: Noonan's syndrome • Giant sinus of Valsalva aneurysms • Aortic regurgitation
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1. Case report
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A 49-year-old man was referred for investigation of a 3-month history of worsening exertional dyspnoea, with an effort tolerance of just 50–100m on the flat. He had no prior history of cardiac or respiratory disease, nor any cardiac risk factors, and he took no medication. His paternal grandfather had died suddenly aged 49, from valvular heart disease.
Examination revealed a prominent webbed neck, pectus excavatum and cubitus valgus, micrognathia and low-set ears. He had a collapsing pulse of 65bpm and a blood pressure of 140/50mmHg. Venous pressure was normal. Auscultation demonstrated a loud aortic regurgitant murmur. The chest was clear, and the remaining examination was normal.
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2. Investigations
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His electrocardiogram showed sinus rhythm with partial right bundle branch block. Chest radiography (Fig. 1
a) showed a large rounded mass emerging from the mediastinum, towards the right. Transthoracic echocardiography revealed giant aneurysms arising from the right and non-coronary sinuses of Valsalva. The aortic valve was trileaflet and colour Doppler demonstrated moderate-to-severe aortic regurgitation due to failure of coaptation of the right coronary cusp. The left ventricle was otherwise normal and there was no other cardiac abnormality.
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Fig. 1. (a) Posterior anterior (PA) chest radiograph showing large rounded mass emerging from the right side of the mediastinum, giving the appearance of a double right heart border. (b) Mid-thoracic computed tomography (CT) image with contrast, demonstrating an 8.4cm aneurysm of the right sinus of Valsalva (A), and a 4.1cm aneurysm of the non-coronary sinus (B). The actual defects in the aortic wall measured 2.4 and 2.2cm, respectively. (c) A three-dimensional reconstruction, cardiac CT angiogram showing left ventricle (LV), proximal aorta (Ao). The right sinus of Valsalva (RVA) and non-coronary sinus aneurysm (NVA) are illustrated. The left main stem (LMS) coronary divides into the left anterior and circumflex artery clearly, with no significant atheroma seen. The right coronary artery (RCA) is compressed proximally and its ostium is obscured by the aneurysms.
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Computed tomography of the chest (Fig. 1b) confirmed aneurysms of the left and non-coronary sinuses, measuring 8.4 and 4.1cm, respectively, each having a narrow neck (2.4 and 2.2cm, respectively). The aorta otherwise appeared normal. Coronary arteriography was not technically possible; therefore, the patient underwent a CT coronary angiogram (Fig. 1c) which identified a normal left coronary system. However, the right coronary ostium could not be identified and the proximal vessel was compressed against the base of the right sinus of Valsalva aneurysm.
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3. Management
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The patient underwent cardiac surgery with replacement of the aortic root with a composite zero porosity valved graft containing a 21mm St Jude mechanical prosthetic valve, and re-implantation of the left coronary artery. On inspection of the aortic valve, there was significant prolapse of the non-coronary aortic cusp secondary to stretching of this leaflet, and the native valve was therefore thought to be not suitable for repair. Fig. 2
a shows the large aneurysm of the right coronary sinus. A small aneurysm developing in the base of the left coronary sinus, immediately above the aortic annulus, was also identified at surgery. The ostium of the right coronary artery could not be identified and the vessel was ligated in its mid-course, and a saphenous vein grafted to the distal vessel. He made an uneventful recovery and was discharged after 7 days.
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Fig. 2. (a) Intraoperative image of the right sinus of Valsalva aneurysm. The patient's head is towards the right of the image with the patient's right towards the top of the image. (b) Van Gibson's stain for elastin of the resected aneurysm (left) with that of a normal aorta (right) used for reference. Note the fibrous scarring with loss of elastin in the wall of the aneurysm.
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Histological examination of the aneurysms (Fig. 2b) revealed a deficiency of medial elastin and also non-specific myxoid degeneration. Chromosomal analysis demonstrated a normal male complement (46XY).
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4. Discussion
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Noonan's syndrome is a relatively common cardiofacial syndrome with an incidence of 1 in 1000–2500 births [1]. It was known as ‘male Turner's syndrome’ until 1963, when Noonan reported a series of nine children with abnormal facies and pulmonary stenosis [2]. Common to both syndromes are short stature, a webbed neck, cubitus valgus and congenital heart disease. However, Noonan's affects both males and females, and has other distinct features: Elfin facies (ocular hypertelorism, down-sloping palpebral fissures, ptosis, low-set ears), skeletal abnormalities (including pectus excavatum), Cryptorchidism and commonly a degree of mental retardation [3].
Cardiac defects are well recognised, though their true incidence is unknown. The most common lesions are pulmonary valve dysplasia and hypertrophic cardiomyopathy [4]. The phenotype is highly variable, and affected persons can escape clinical problems and accurate diagnosis. In a series of 118 patients [4], 27% had pulmonary stenosis or dysplasia. Left ventricular hypertrophy was seen in 25%, most commonly with localised septal hypertrophy, with a further 10% having secundum atrial septal defects. Other reported abnormalities include ventricular septal defects, patent ductus arteriosus, tricuspid atresia, mitral stenosis and subaortic stenosis [3,4].
Inheritance is autosomal dominant. The PTPN11 gene on chromosome 12 has been implicated [1]. In a recent study, 45% of 119 unrelated Noonan subjects carried mutations, with a significantly higher prevalence amongst familial cases. The gene's product is a key component in several signal transduction pathways that control protean development, particularly cardiac semilunar valvulogenesis [1].
Sinus of Valsalva aneurysms occur infrequently in the general population, with an incidence of approximately 0.1% [5]. The majority are congenital, due to a defect in aortic media, but they may also follow pathologies including atherosclerosis, trauma, endocarditis and syphilis [6]. In a recent series of 129 patients [5], 52% of aneurysms arose from the right coronary sinus, 34% from the non-coronary sinus and 14% from the left coronary sinus. Most are clinically silent until they rupture, but enlarging aneurysms can lead to right ventricular outflow tract obstruction, coronary artery compression, complete heart block, and they are a potential source of cerebrovascular emboli [6]. Symptoms are non-specific and include dyspnoea, fatigue, chest pain and palpitations [5]. Rupture typically occurs into the right ventricle (or right atrium for non-coronary sinus aneurysms) and without surgery carries a poor prognosis [7]. Operative procedures include simple placation, patch repair, aortic root replacement, and aortic valve replacement/repair. Prosthetic aortic root replacement and re-implantation of the coronary arteries is performed in patients with a dilated annulus and multiple sinus involvement, where simple placation or patch repair is not possible.
There is only one other report of un-ruptured sinus of Valsalva aneurysms in Noonan's syndrome. In 1989, Morgan et al. [8] reported a 42-year-old male with webbed neck, short stature, cubitus valgus, and genu valgum who presented with palpitations, dyspnoea and chest pain. Chest X-ray abnormalities were mistakenly thought to represent enlargement of the main pulmonary artery. Aneurysms of the left and right sinuses of Valsalva were diagnosed at cardiac catheterisation and aortography. Single cases of aortic dissection [9] and aortic root dilatation [10] have also been reported, the latter associated with intracranial aneurysm and hyper-extensible metatarsal joints. These observations suggest the primary defect being one of abnormal connective tissue, as implied by our histological studies. The high incidence of potentially serious cardiac abnormalities in patients with suspected Noonan's syndrome merits careful cardiological examination and investigation.
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References
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Abstract
1. Case report
