Complete Sinus Inversus and Bicuspid Aortic Valve Stenosis

12-lead ECG.
RCA originating from a left-sided aortic cusp (30° LAO view). An anomalous conus branch ostium is also noted (inset).
Chest roentgenogram showing a long, horizontal bronchus on the right side (short arrow), right-sided gastric bubble (long, solid arrow) and elevated left hemidiaphragm (dashed arrow).
Transesophageal echocardiogram demonstrating a bicuspid aortic valve with left and right cusps, and an anterior-posteriorly directed commissure. Arrow indicates ostium of left main coronary artery.
Mirror image left coronary artery systems demonstrating inverted, non-diseased vessels with left main arising from right-sided cusp. LAD = left anterior descending; LCx = left circumflex; LMCA = left main coronary artery.
Aortogram demonstrating a right-sided aortic arch.
Author(s): 

Deepak Bhakta, MD, Jeffrey A. Breall, MD, PhD, Vijay G. Kalaria, MD

Key words: adult congenital heart disease, angiography, bicuspid aortic valve stenosis, dextrocardia, situs inversus

Patients with congenital heart disease present interesting challenges during heart catheterization. We present an adult patient with complete situs inversus with congenital bicuspid aortic valve stenosis, a hitherto unreported association, and offer technical tips for performing left and right heart catheterization.

Case Report
A 60-year-old male presented with exertional dyspnea, paroxysmal nocturnal dyspnea, orthopnea and bilateral lower extremity edema. He also reported occasional exertional chest pain over the right precordium without radiation to the arm or jaw. He had a known history of hyperlipidemia, diabetes mellitus and obstructive sleep apnea. He denied any episodes of syncope, fever, respiratory tract infections or illicit drug use and remembered being told by a physician that “his organs are reversed in position”. He was unaware of any family history of congenital heart disease, dextrocardia or situs inversus. Physical examination showed clear lung fields with palpation of the apical impulse in the fifth intercostal space at the right mid-clavicular line. On auscultation, there was normal intensity of S1 and S2 without any gallops. A grade III/VI systolic ejection murmur was audible over the right upper sternal border and right precordium with radiation to the carotid arteries, which were somewhat delayed in upstroke. Peripheral pulses were normal in intensity, with 2+ bilateral lower extremity pitting edema.

A 12-lead electrocardiogram (ECG) with leads in the usual precordial position revealed inverted P waves in lead I with a negative major QRS deflection. Upright P waves with a positive QRS deflection were seen in lead aVR with mirror image findings in lead aVL, and an abnormal precordial progression of R wave from lead V1 through V6 (Figure 1). Chest roentgenogram showed a long, horizontal bronchus on the right side, with elevation of the left hemidiaphragm (Figure 2). Aortic valve stenosis was suspected clinically and a transesophageal echocardiogram (TEE) was performed due to suboptimal images obtained through transthoracic echocardiography. TEE revealed a stenosed, bicuspid aortic valve with right and left-sided cusps, and an anterior-posteriorly directed commissure (Figure 3). The measured valve area by planimetry was 1.1 cm2, with mild aortic regurgitation and preserved left ventricular systolic function. Spectral Doppler was not performed; therefore, transvalvular gradients were not estimated. The patient was referred to our catheterization laboratory for evaluation of aortic valve gradients and to rule out coexistent coronary artery disease.

Right heart catheterization was performed using reverse maneuvering of the pulmonary artery catheter, e.g., counterclockwise rotation for passage from the right ventricle to the main pulmonary artery. Elevated right heart pressures consistent with moderate pulmonary hypertension were demonstrated (mean right atrial pressure of 10 mmHg, right ventricular pressure of 51/13 mmHg, pulmonary arterial pressure of 51/18 mmHg and pulmonary artery wedge pressure of 21 mmHg). Cardiac output and index were within the normal range (6.7 L/minute and 2.5 L/minute/m2, respectively). Serial oximetry showed no evidence of intracardiac shunting. During guidewire passage from the right femoral artery to the aortic root, a right-sided aortic arch was evident. Coronary angiography was performed using preformed Judkins catheters (JL4 and JR4) and revealed the coronary ostia to be in the contralateral coronary cusps, as expected. Coronary artery engagement was performed in a right anterior oblique view, with imaging using mirror image views. The coronary arteries were without any significant obstructive atherosclerotic disease (Figures 4 and 5). In addition, an anomalous conus branch ostium was evident just above the right coronary artery origin (Figure 5, inset). The aortic valve was deformed and was crossed using a straight wire and an angled pigtail catheter. Ventriculography and aortography documented dextrocardia with a normal left ventricular systolic function, a right-sided aortic arch, and no significant aortic regurgitation (Figure 6). Mean and peak instantaneous transvalvular gradients of 38 and 50 mmHg were observed, with an aortic valve area of 1.0 cm2.

Despite his insidious course, the advanced symptoms noted in our patient could not be completely attributed to the observed aortic valve area, gradient and preserved left ventricular function, which are suggestive of only moderate valvular disease. It was felt that some of his symptoms were secondary to underlying pulmonary disease. Given the presence of moderately severe aortic stenosis and symptoms, our patient was referred to the cardiovascular surgical service, where he was felt to be an acceptable surgical candidate and was offered aortic valve replacement. However, the patient wished to defer surgery in favor of expectant management by serial echocardiography. Several months after his presentation, the patient continues to do well without any progression of symptoms.

Discussion
Situs inversus is part of a spectrum of congenital abnormalities in patients without visceral heterotaxy. It can range from the simplest of these disorders, dextrocardia (with situs solitus), which only involves cardiac malrotation, to situs inversus totalis, which involves dextrocardia with complete, left-right rotation of the visceral organs. The latter was present in our patient, though he also had a congenital bicuspid aortic valve, a hitherto unreported association. In situs inversus with dextrocardia, a morphologic right bronchus is concordant with the morphologic right atrium and trilobed lung on the left with inverted positions of atria (atrio-visceral concordance) and a right-sided heart.1 Compete situs inversus (i.e., situs inversus with dextrocardia) is one of the most common types of cardiac malposition seen in adults. Two other varieties of cardiac malposition syndrome, situs solitus (normal visceral position) with dextrocardia and situs inversus with levocardia (heart in the left side of the chest with the apex pointing to the left), are usually recognized earlier because of accompanying congenital abnormalities.

Visceral heterotaxy refers to the anomalous arrangement of visceral and vascular structures without relative concordant arrangements.1 These disorders are further subdivided into right and left isomerism. Right isomerism, consisting of bilateral morphologic right bronchi, bilateral morphologic right atrial appendage, a transverse liver and bilateral trilobed lungs, is more commonly associated with dextrocardia and asplenia. Left isomerism, with bilateral morphologic left bronchi, bilateral morphologic left atrial appendage, transverse liver, right-sided stomach and bilateral bilobed lungs, is more commonly associated with levocardia and polysplenia. These conditions are suspected when features of both situs solitus and inversus are present in a given patient, making the diagnosis unclear.2 These patients have a significantly higher incidence of complex congenital heart disease.3

Though controversial, it is generally thought that the incidence of congenital heart disease with dextrocardia associated with visceral situs inversus is that of the general population.3–5 Our patient displayed features of dextrocardia and situs inversus, which would suggest a structurally normal heart. However, he was found to have a congenitally bicuspid valve, which has never been reported in this group of patients. Several instances of obstruction to left ventricular outflow have been reported in these patients. However, in each of these cases, the site of obstruction was either subvalvular or due to aortic atresia. The first case involved a 38-year-old male with dextrocardia and situs inversus totalis with both subpulmonic and subaortic stenoses. He was also found to have a ventricular septal defect and a single coronary artery.4 His aortic valve was structurally normal and the patient eventually underwent successful repair of all of his lesions. In the second instance, a newborn male with dextrocardia and situs inversus was found to have several congenital defects, including a hypoplastic left ventricle and ascending aorta, atrial septal defect and an underdeveloped left atrioventricular connection. The aortic valve itself was atretic.3 This infant did not survive for more than several days. Kartagener’s syndrome, a variant of immotile cilia syndrome, is predominantly an autosomal recessive condition and is characterized by situs inversus in conjunction with immotile cilia.6

In a patient with dextrocardia, optimal angiographic views are obtained by mirror image positioning of the image intensifier. ECG interpretation is facilitated by switching the limb leads and by recording right precordial leads from mirror image of normal left precordial positions. For patients with situs solitus with dextrocardia, limb leads should be left in the normal position and only precordial leads should be reversed. Exercising caution prior to ECG lead switching and appropriate labeling will avoid confusion on later interpretations. Proper attention to physical findings, chest roentgenogram and ECG will facilitate optimal pre-procedure recognition of cardiac malpositions and yield high-quality diagnostic information, including recognition of coexistent congenital anomalies in a patient presenting for unrelated adult cardiac problems. Finally, bicuspid aortic valve leaflets are oriented in an anterior-posterior or right-left fashion. The commissural arrangement is subsequently positioned in a perpendicular orientation, e.g., left-to-right, or in an anterior-posterior position, respectively.6 The patient presented above demonstrated the latter variant, with the coronary artery ostia in the posterior aspect of each cusp, as expected.


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