Witnessed Rupture of a Sinus of Valsalva Aneurysm into the Right Ventricle Presenting as Cardiogenic Shock

Introduction

The sinuses of Valsalva are three small dilatations or cavity-like structures in the aortic wall above the attachments of the aortic cusps. They are known as the right coronary, left coronary and non-coronary sinuses, as defined by the associated coronary artery. First described in the early 1800’s by Thurnam (in a post-mortem description) and Hope, sinus of Valsalva aneurysms (SVA) are extremely rare, with an incidence of less than 0.15%.^1–4 Most develop in the right coronary and non-coronary sinuses, predominantly rupturing into the right atrium or ventricle.^5–10 Rupture into the left atrium and left ventricle, and dissection into the interventricular septum have also been reported.^11–14 Occurring either as a congenital or acquired lesion, they will typically remain asymptomatic until rupture manifests with symptoms of outflow tract obstruction, angina, acute heart failure, tamponade or conduction disturbances.^3,15,16 Alternatively, patients may remain asymptomatic or have an insidious onset of symptoms.^3,16–20 We report the unique experience of a witnessed rupture of a right SVA into the right ventricle during transthoracic echocardiogram, with development of acute severe cardiogenic shock, successfully treated with medical stabilization and eventual surgical repair.

Case Report

A 33-year-old Hispanic male presented to his primary care physician (PCP) with approximately a one-month history of lower extremity edema and fatigue, without any chest pain, dyspnea or orthopnea. He stated he was diagnosed with a heart murmur during childhood, which was never evaluated. Physical examination by the PCP revealed the patient to be in no distress, afebrile with a blood pressure of 130/70 mm Hg, clear lung fields, a III/VI holosystolic murmur best heard at the apex and 1–2+ pitting edema in bilateral distal lower extremities. Chest X-ray revealed cardiomegaly with increased pulmonary vascularity and congestion and a prominent aorta. The patient was started on diuretics and referred to cardiology clinic for an echocardiogram.

Due to financial reasons, the patient did not arrive at the clinic until 31/2 weeks later. On initial evaluation he reported improvement in symptoms while on his medication (enabling him to continue working as a landscaper), that he was in no distress and had normal vital signs. Transthoracic echocardiography demonstrated a right SVA, with a large right ventricle with end diastolic diameter of 5.2 cm, and moderate obstruction of the right ventricular outflow from the SVA. The aortic valve was tri-leaflet, dense and sclerotic, with severe aortic regurgitation due to distortion of the right coronary cusp and severe enlargement of the left ventricle with end diastolic diameter of 7.8 cms. There was no evidence on the initial echocardiogram of rupture of the SVA without any evidence of shunt. During the procedure, however, the patient was noted to develop tachypnea, tachycardia and diaphoresis. He was immediately transferred to the emergency department in mild respiratory distress where initial exam noted heart rate 104, respiratory rate 20, blood pressure 125/63 mm Hg, room air oxygen saturation of 97%, no jugular venous distention, IV/VI systolic and diastolic murmur, 2+ peripheral pulses and clear lung fields. Results of a complete blood count, blood chemistry and cardiac enzymes were all normal. The electrocardiogram showed sinus tachycardia and biventricular enlargement.

While in the emergency department, the patient developed worsening respiratory distress and severe hypotension with pulmonary edema. He required emergency intubation and inotropic support for severe pulmonary edema and cardiogenic shock. Emergent transesophageal echocardiogram confirmed acute rupture of a large right SVA with high velocity flow into the massively enlarged right ventricle during both systole and diastole. The aortic valve was hyper-echogenic with significant morphological distortion and severe aortic insufficiency. Right heart catheterization revealed a pulmonary artery pressure of 52/33 mm Hg, with an aortic pressure of 73/40 mm Hg and a 22% step up in oxygen saturation between the right atrium and right ventricle. Left heart catheterization demonstrated totally normal left and right coronary arteries. While the aneurysm significantly obstructed the right ventricular outflow tract and displaced the right coronary artery upward, there was no evidence of any coronary arterial compression. Passage of the pigtail catheter from the aorta to the right ventricle through the ruptured SVA was seen.

After stabilization using inotropic agents, diuretics and eventually nesiritide, the patient was referred for surgery. Percutaneous closure of the SVA was not considered as an option, due to the presence of severe aortic insufficiency.^21–23 During surgery the above-mentioned diagnoses were confirmed with evidence of a 1.8 cm communication between the SVA to the right ventricle, with a dissecting ventricular septal defect and severe aortic insufficiency, due to distortion of the right coronary cusp. The right ventricle was “gigantic”. The aortic root and aortic valve were replaced with a 23 mm St. Jude mechanical valve (St. Paul, Minnesota) and Hemoshield conduit with patch closure of the VSD and reimplantation of the coronary arteries. The patient has been followed in our cardiology clinic with complete recovery and is now asymptomatic and back to work as a landscaper. His follow-up echocardiogram has shown normal mechanical aortic valve function with good left ventricular function, and the right ventricle has regained normal size and function. The right ventricular outflow obstruction seen on the initial echocardiogram has completely resolved.

Discussion

Aneurysms of the sinuses of Valsalva are quite uncommon with an incidence of less than 0.15% of all the congenital heart defects. They are found more frequently in Asian populations and at rates 3–4 times higher in males than females.^1–4,7,24 The right coronary sinus is most often involved (77–94%), followed by the noncoronary (5–12%) and left coronary sinuses (1%).^5,9,25 A congenital defect in the annulus fibrosus of the aortic valve leads to its separation from the aortic media in the coronary sinus. A deficiency of normal elastic tissue and abnormal development of the right and left distal bulbous septum yield an anatomic propensity for aneurysmal formation in the right and non-coronary sinuses. Acquired structural defects due to infections (syphilis, tuberculosis, and bacterial endocarditis), degenerative diseases (cystic medial necrosis, Behcet’s disease, Marfan’s syndrome, and atherosclerosis) and chest trauma can also disrupt continuity between the aortic media and annulus.^3,15,26,27

Aortic pressures in the area of weakness eventually result in aneurysmal formation. Due to a paucity or total lack of symptoms, diagnosis and treatment is typically delayed until the third or fourth decades of life.³ Diagnosis in the neonatal period and young childhood as well as late adulthood has also been reported.^28–31,33 Symptoms may develop by means of several mechanisms. The SVA may function as a space-occupying lesion and thereby 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 disturbances.^3,31–33

Aneurysms of the right coronary sinus typically protrude and rupture into the right atrium or right ventricle and those of the non-coronary sinuses, into the right atrium. The rare left SVAs have a propensity for protrusion and rupture into the left atrium or ventricle, pulmonary artery or into the myocardium. Because of the location of the left coronary sinus with exposure to the epicardium, left SVAs may also rupture into the epicardium, with potential to compress the left coronary artery. Associated anomalies include, most commonly, ventricular septal defect (30–52%), (especially true of SVAs rupturing into the right ventricle), 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 defect.^{3,7–9,20,24,34}

Rupture may vary in presentation from few or no symptoms to acute decompensation, depending on the size, location and mechanical effect of the aneurysm. Almost all patients will experience some degree of heart failure with a significant portion presenting with acute onset.^3,24 Signs and symptoms include shortness of breath, chest pressure, tachycardia, wide pulse pressure and systolic and diastolic murmurs.^3,15,33Once suspected, diagnosis can be confirmed using a variety of invasive and noninvasive tools. Echocardiography, both transthoracic and transesophageal, 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 may physically demonstrate direct communication between the SVA and adjacent cardiac chambers.^3,29,35,36

Chest radiograph 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 arrhythmias. ^3,31,32,37 Before treatment became available, mortality for ruptured SVA was extremely high. The first successful surgical repair was reported in 1957. Today, although accounting for less than 1% of all cardiac surgeries, repair of a ruptured SVA carries an operative mortality rate of less than 5%, with post-operative life expectancy approaching that of the general population.^{3,7,20,24,37,38}

Percutaneous closure devices are being investigated as a potentially less invasive treatment in certain clinical scenarios.^39–41 Our patient demonstrated many of the classical clinical findings of a chronic SVA and the potentially acutely catastrophic consequences of its rupture. His childhood murmur may have been the result of right ventricular outflow tract obstruction or aortic insufficiency. The development of signs and symptoms of heart failure probably occurred secondary to the severe chronic aortic regurgitation and possibly also right heart compromise secondary to outflow obstruction from the aneurysm. The acute decompensation with clear evidence of cardiogenic shock was secondary to the witnessed rupture of the SVA. This case demonstrates the importance of rapid and thorough evaluation of patients with new onset congestive heart failure in otherwise healthy young individuals. We report the uniquely fortuitous occurrence of observing his aneurysmal rupture in the hospital setting. This allowed us the opportunity to medically stabilize and surgically repair what otherwise might have proven to be a fatal defect.