Introduction

Aneurysms of the sinuses of Valsalva (ASV) are thin-walled outpouchings, most commonly involving the right or the non-coronary sinuses. It was first described by John Thurnam in 1840 in a patient with ruptured aneurysm of sinus of Valsalva. Clinicians then described other cases of unruptured aneurysms and applied anatomic descriptions1. They are rare lesions with an incidence of less than 0.1% in the general population. These aneurysms are mostly a result of a congenital defect in aortic media, and rarely an acquired degeneration. Most patients remain asymptomatic until the aneurysm ruptures, and they usually present with sudden onset chest pain, shortness of breath and easy fatigability2. We report two cases with ASV, one of them with atypical presentation of ruptured ASV in whom the aneurysm was incidentally discovered during work up for coronary artery disease.

Case 1

In November 2005, a 45-year-old man presented to the Emergency Department with severe retro-sternal chest pain associated with mild shortness of breath. He had a past medical history of type 2 diabetes and hypertension. He was of normal height and body build, with normal features and normal vision. Chest auscultation was normal. Electrocardiogram showed changes of acute anterior MI. Chest X-ray was normal. Trans-thoracic Echocardiography demonstrated regional wall motion abnormalities with impaired left ventricular systolic function (EF = 40%). The report described dilatation of the right coronary sinus of Valsalva with calcified cavity draining into the right atrium.
CT-angiography revealed a heavily calcified aneurysm of the right coronary sinus of Valsalva with a pedunculated appearance and a long neck extending towards the inter-atrial septum and entering the right atrium (Figure 1). The origin of the right coronary artery was displaced upwards, arising from the dilated right coronary sinus, with multiple atheromatous lesions along it’s length down to it’s bifurcation at the origin of the PDA. A calcified lesion was also found in the proximal part of the LAD artery. Coronary angiography confirmed these findings, and clearly showed a jet of contrast going through the aneurysmal tract to the RA. It also revealed severe CAD with 80% proximal LAD, 70% mid CX lesions, and diffusely diseased RCA. The patient was offered surgery but he was reluctant. He was lost to follow up until November 2006 when he presented again to the Emergency Department with pulmonary edema and non-ST-elevation MI. This time the patient accepted the recommended CABG operation with repair of the ruptured ASV.

 

Fig.1: Cardiac CT scan of case 1 showing the ruptured ASV with calcification of the aneurysm and the fistulous tract between the aneurysm of the right sinus of Valsalva and the right atrium.

 

Surgical Technique

Cardiopulmonary bypass was started with aortic and bi-caval cannulation. Cardioplegic arrest was achieved with retrograde hypothermic hyperkalemic cardioplegia, repeated every 20 minutes. There was huge aneurysmal dilatation of the right coronary sinus of Valsalva with anterior-superior displacement of the right coronary ostium (Figure 2). The annulus of the aortic valve was normal in size. The aneurysm was approached through both the aorta and the RA, and was completely dissected. The redundant wall of the aneurysm was excised (including the ostium of the right coronary artery), and the aortotomy was closed. The fistulous tract to the right atrium was excised, and sutured. Concomitant coronary artery bypass procedure was done using a segment of vein graft anastomosed to distal RCA, and LIMA pedicle graft to LAD. Intra-operative TEE demonstrated complete exclusion of the ASV.

 

Fig. 2: Intra-operative picture of case 1 showing the ASV with the green arrow pointing at the fistulous tract to the right atrium.

Case 2

A 24-year-old Pakistani man presented to the Emergency Department with one-month history of intermittent episodes of palpitation and chest pain. Past medical history was unremarkable. The patient was afebrile, blood pressure was 120/64 mmHg. Lung fields were clear, but a machinery cardiac murmur was heard. EKG showed LVH. Chest X-ray was normal. Trans-thoracic and transesophageal echocardiography revealed aneurysmal dilatation of the right coronary sinus of Valsalva protruding into the right ventricle. The non-coronary and the left coronary sinuses were also dilated. A high velocity color Doppler flow was noted in the RVOT during systole and diastole suggesting aortic-right ventricular communication (Figure 3). A small sub-pulmonic VSD was also noted. Both right and left ventricular end diastolic dimensions were normal. Elective repair of the ruptured ASV and VSD closure was recommended.
 

Fig. 3: Echocardiogram of case 2 showing ASV with the arrow pointing to the rupture into the right ventricle, and the color Doppler flow in the fistula.

Surgical Technique

The procedure was done via median sternotomy with cardiopulmonary bypass. The aorta was cross clamped and incised above the aortic valve. Transverse right ventriculotomy was made across the RVOT. The aneurysm of the sinus of the Valsalva and the right coronary artery could then be seen easily. A classic windsock tract was seen arising from the right coronary sinus protruding into the right ventricular out flow tract. The aortic valve annulus was not dilated. The opening of the aneurysm, which was about 1cm in diameter, was closed with a pericardial patch from the aortic side. Although the orifice of the right coronary artery was displaced downward, it was not compromised by closure of the mouth of the aneurysm. After closing the aortotomy and unclamping the aorta, blood was seen spurting from a tiny hole from the left ventricle into the right ventricle at subpulmonic level suggesting subpulmonic VSD. It was closed with direct sutures. Intra-operative TEE showed competent aortic valve, and complete closure of the fistula and the VSD.

Pathophysiology

Primary congenital aneurysm of the sinuses of Valsalva (ASV) is a rare anomaly and it is the least common of all aortic aneurysms. Secondary causes of such aneurysms are atherosclerosis, syphilis, cystic medial necrosis, or infective endocarditis. About 60% of these aneurysms arise from the right sinus, 25% from the non-coronary, and the remaining 9% from the left coronary sinus3,4,5.
The basic pathological anatomy, as emphasized by Edwards2, is the loss of continuity between the media of the aortic wall and the aortic valve annulus. A somewhat similar lack of continuity below this area between the aortic valve annulus and the membranous ventricular septum occurs in ventricular septal defects. This similar embryological origin is probably responsible for the fact that about one-fourth of the aneurysms of the right coronary sinus are associated with a ventricular septal defect, while a similar association is rare with aneurysms of the left or the non-coronary sinuses. Distortion and prolapse of the sinuses and aortic valve tissue can lead to progressive aortic valve insufficiency6.
Unruptured aneurysm may cause distortion and obstruction of the right ventricular outflow tract. Distortion and compression may also cause myocardial ischemia by coronary artery compression, and possibly heart block by compressing the conduction system. Although ASV can protrude and rupture into any cardiac chamber, Aneurysms of the right coronary sinus typically protrude and rupture into the right atrium or the right ventricle, while those of the non-coronary sinus protrude into the right atrium6,7,8. The rare left SVA have propensity for protrusion and rupture into the left atrium or ventricle, the pulmonary artery, the myocardium or the epicardium, with the potential to compress the left main coronary artery. Associated anomalies include ventricular septal defect (30-52%), and aortic valve insufficiency (18-43%). Others include pulmonary stenosis, coarctation of the aorta, bicuspid aortic valve, subaortic stenosis, Tetralogy of Fallot, patent foramen ovale and atrial septal defect9,10,11.
Asian patients have high incidence of ASV of the right coronary sinus, with a marked tendency to protrude and rupture into the right ventricle rather than right atrium. Asian patients with RASV also have a higher incidence of VSD (50%), typically supra-crystal type, compared with a lower incidence (30%) in Western patients, typically with VSD of perimembranous type12.
The two cases that are presented in this article have different pathophysiology. In the first case, the etiology is atherosclerosis causing coronary artery disease, degeneration and aneurysm formation of the right coronary sinus. Congenital factor is the most likely pathology in the second case, especially with a ventricular septal defect as part of the picture representing in an Asian patient with a congenital aneurysm of the right coronary sinus rupturing into its usual destination, the right ventricle.

Incidence

The incidence of ASV in the Western Hemisphere and in the USA is approximately (0.1% - 3.5%), but its prevalence is higher in Asian population because of the higher incidence of associated supra-crystal (sub-pulmonic) ventricular septal defect7. Very few cases are reported with acquired ASV, and the incidence of the disease mentioned above mainly represents the congenital forms. The first case presented in this report is a rare finding of acquired ASV. In 1979, M. E. Debakey reported one similar case of acquired ASV associated with sever coronary atherosclerosis that was treated surgically. He addressed the unusual features of that case, the presenting symptoms (angina pectoris) and the cause of the aneurysm (atherosclerosis)13.

Clinical presentation

Children with this condition most commonly are asymptomatic. Symptoms typically present in young adulthood (usually in patients < 30 year of age), either from enlargement of the aortic root and compression of surrounding structures, or from manifestations of a ruptured aneurysm. The ASV may function as a space-occupying lesion, and thereby may obstruct the left or right ventricular outflow tracts, interfere with aortic valve function, distort the coronary ostia with ischemic consequences, or compress the conducting system, resulting in conduction disturbances14. Rupture may vary in presentation from few or no symptoms to acute decompensation, depending on the size, location and mechanical effects of the aneurysm. Almost all patients will experience some degree of heart failure, with a significant portion presenting with acute onset15.
Physical findings depend on whether or not the aneurysm is ruptured, and on the absence or presence of associated congenital anomalies. Diagnostic physical signs may be absent in unruptured aneurysm. A loud continuous murmur occurs due to rupture into a cardiac chamber, usually best heard at the left para-sternal border. A para-sternal thrill can be palpable due to associated ventricular septal defect. Pounding pulses may be present suggesting hyper-dynamic circulation from large left to right shunt or aortic insufficiency. Diastolic murmur may occur due to aortic incompetence. Bi-basillar rales may be present due to congestive heart failure. Ejection systolic murmur can also develop from RVOT compression6.
Our first case was diagnosed incidentally while being investigated for coronary artery disease, and the main presenting symptom was typical ischemic chest pain the and physical examination was unremarkable. The second case was referred to cardiology clinic because of a recent history of intermittent palpitation and chest pain. Physical examination revealed a machinery murmur best heard at the left parasternal border along with findings of hyperdynamic circulation, such as pounding pulses.

Diagnosis

Once suspected, the diagnosis can be confirmed using a variety of invasive and noninvasive tools. Chest X-ray findings tend to be non-specific, showing cardiomegaly and/or pulmonary congestion. Similarly, electrocardiography may show left, right, or biventricular hypertrophy, ischemia or infarction, conduction abnormalities or arrhythmias16,17.
Echocardiography, both trans-thoracic and trans-esophageal, serves as a quick, noninvasive method, able to provide information on size and location of aneurysmal dilatations and fistulous tracts, cardiac chamber involvement, degree of aortic insufficiency and other valvular dysfunction, and identification of any associated anomalies or complications. Computed tomography and magnetic resonance imaging may reveal more detailed anatomy. Angiography is useful in assessing coronary artery compression, measuring oxygenation step-up between right atrium and ventricle, and demonstrating direct communication between the SVA and adjacent cardiac chambers18,19.
Although echocardiography is a powerful diagnostic tool in detection of ASV, our observation showed that cardiac catheterization and CT angiography are often useful in establishing the diagnosis and evaluating the hemodynamic effects of the ruptured aneurysm, as demonstrated in our first case. In the second case, Echocardiography was the diagnostic tool which clearly showed the aneurysm of the right coronary sinus of Valsalva protruding and rupturing into the right ventricular out flow tract along with a small subpulmonic VSD.

Management

Transcatheter closure of ruptured SVA has been successfully performed using Amplatzer devices. However, surgical treatment is the recommended strategy in the majority of patients, and medical treatment is reserved for hemodynamic stabilization, prophylaxis or treatment of endocarditis, and management of arrhythmias and/or cardiac ischemia7,20.
Early aggressive medical treatment and prompt surgical therapy is recommended when ruptured ASV is diagnosed. Delay in the operation may lead to worsening of symptoms, development of complications and death. Surgical approach is individualized depending on the size and the extent of the aneurysm, the presence of associated anomalies and the presence of complications. When ASV are small, they are frequently repaired by direct closure; when they are large, the repair usually requires the use of prosthetic patch. Extensive aneurysm may require aortic root reconstruction or Bentall (valve-conduit) procedure7,8,20,21. In this report, concomitant CABG operation in addition to repair of the ruptured ASV was needed in the first case. While in the second case, the operation was performed using trans-aortic approach to repair the aneurysm with a pericardial patch, and the VSD was closed simultaneously.
No consensus exists as to when to perform surgery on a fortuitously discovered unruptured ASV. Serial monitoring of these patients using echocardiography or MRI can be done with the plan to undertake elective repair of a known ASV with repair of any other cardiac shunt or defect22,23.

Mortality and morbidity

Because of the rarity of this disease, no definite mortality and morbidity figures are reported. However, rupture of the aneurysm is the main prognostic factor leading to a number of complications which are unfortunately the usual presenting features in the majority of patients.
Sudden cardiac death has been reported following rupture of the aneurysm due to overwhelming congestive heart failure, cardiac tamponade, infective endocarditis, arrhythmia or coronary ischemia. Late death usually occurs within 1 year after rupture if the shunt is substantial. Longer survival may occur if the shunt is small6,15,21. Although our patients presented with ruptured ASV, no serious complications were encountered in both cases.
Elective surgical repair has low operative mortality rate (5%), and subsequent survival approaches that of healthy population, making elective surgical repair of this condition essential. Long term survival is related to aortic insufficiency, the use of prosthetic valves and the associated abnormalities. Reoperation is more frequent if the aneurysm was repaired by direct suture than by patch closure21.¨

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