CardioVascular and Interventional Radiology
© Springer-Verlag New York, Inc. 2003 Published Online: 20 May 2003
Cardiovasc Intervent Radiol (2003) 26:309 –311 DOI: 10.1007/s00270-003-2635-8
Utility of Magnetic Resonance Imaging in Cardiac Venous Anatomic Variants* Robert E. Eckart,1 W. Shad Leitch,2 Eric A. Shry,1 Richard A. Krasuski,3 Michael J. Lane,4 Kenneth M. Leclerc1 1
Cardiology Service, Brooke Army Medical Center, 3851 Roger Brooke Drive, Fort Sam Houston, Texas 78234-6200, USA Internal Medicine, Brooke Army Medical Center, 3851 Roger Brooke Drive, Fort Sam Houston, Texas 78234-6200, USA 3 Cardiology Service, Wilford Hall Air Force Medical Center, Texas, USA 4 Department of Radiology, Brooke Army Medical Center, 3851 Roger Brooke Drive, Fort Sam Houston, Texas 78234-6200, USA 2
Abstract The incidence of persistent left superior vena cava (PLSVC) is approximately 0.5% in the general population; however, the coexistent absence of the right SVC has a reported incidence in tertiary centers of 0.1%. The vast majority of reports are limited to pediatric cardiology. Likewise, sinus of Valsalva aneurysm is a rare congenital anomaly, with a reported incidence of 0.1–3.5% of all congenital heart defects. We present a 71-year-old patient undergoing preoperative evaluation for incidental finding of aortic root aneurysm, and found to have all three in coexistence. Suggestive findings were demonstrated on cardiac catheterization and definitive diagnosis was made by magnetic resonance imaging. The use of MRI for the diagnosis of asymptomatic adult congenital heart disease will be reviewed. Key words: MR-angiography—Vena cava—Cardiac—Congenital
superior vena cava, and sinus of Valsalva aneurysm. The few reports of absent right SVC in adults have been detected after technical difficulties encountered with right heart catheterization. This is the first case of both this particular triad of congenital abnormalities, as well as the first case in which an adult patient without known congenital heart disease was found to have clinically significant variant venous return through the use of MRI. In this patient who was subsequently referred for aortic root replacement, the MRI findings were critical to surgical management.
Case Report The patient is a 71-year-old man who had incidental finding of aortic insufficiency on routine physical examination. His medical history was significant only for percutaneous transluminal coronary angioplasty seven years previously at an outside institution. The patient denied anginal equivalent symptoms following revascularization, with a self-reported exercise
Non-invasive imaging modalities are being used with increasing frequency to evaluate structural cardiac disease. MRI, in particular, has become the preferred initial diagnostic test of choice for evaluation of pediatric congenital heart disease. MRI is less often used in the adult population due to the ability of echocardiography to evaluate most acquired adult valvular and myocardial conditions. Although MRI is a frequently used modality to evaluate the aorta and great vessels, it is increasing in popularity as a cardiac structural imaging modality. Variant cardiac venous return is felt to have an incidence of approximately 0.5% in the general population. Its finding has clinical significance in those patients that subsequently require cardioplegia during open heart surgery. During routine evaluation for a patient with aortic root dilatation, we “uncovered” the coexistence of persistent left superior vena cava (PLSVC), absent right
Correspondence to: CPT R.E. Eckart, Brooke Army Medical Center, Cardiology Service (ATTN: MCHE-MDC), 3851 Roger Brooke Drive, Fort Sam Houston, TX 78234-6200; email:
[email protected] *The views expressed in this manuscript are those of the authors and do not reflect the official policy or position of the Department of the Army, Department of Defense, or the U.S. Government.
Fig. 1. Aortogram using 6-French pigtail catheter in left-anterior oblique view revealing sinus of Valsalva aneurysm.
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Fig. 2. Axial ECG gated T1 weighted MRI image shows an enlarged left superior vena cava (arrow) and absence of the right superior vena cava. Ascending aorta (AA). Left Ventricle (LV). Left Atrium (LA).
tolerance of greater than 2.5 miles of walking twice daily. His remote medical history was significant for self-reported premature birth and questionable obstructive pulmonary disease in this lifelong nonsmoker. Plain film chest radiograph was unremarkable. Transthoracic echocardiography revealed mild concentric left ventricular hypertrophy and a normal ejection fraction. The right ventricle and atrium were moderately dilated with normal right ventricular function. The aortic root annulus was mild to moderately enlarged (48 mm), and the ascending aorta was mildly enlarged (42 mm). The inferior vena cava was plethoric, with limited collapse during inspiration. The aortic valve was mildly thickened with trace to mild aortic insufficiency. The coronary sinus was noted to be moderately dilated on parasternal long-axis views. For further quantification of aortic root dimensions, the patient underwent magnetic resonance imaging (MRI) which demonstrated an enlarged aortic root, measuring 54 mm in greatest dimension at the level of the sinuses of Valsalva and 37 mm above the sinuses, consistent with sinus of Valsalva aneurysm. Following discussion with surgery, the patient elected to undergo surgical repair. In light of his previous cardiac history, he underwent preoperative cardiac catheterization. Biplane aortography revealed a sinus of Valsalva aneurysm measuring 55.2 mm with a sinotubular junction of 36.5 mm and ascending aorta of 36.3 mm (Fig. 1). There was trace aortic regurgitation. Right heart catheterization via the right femoral approach revealed no significant step-up in cardiac chamber oxygenation, though the superior vena cava could not be located despite repeated attempts using a balloontipped catheter under fluoroscopic guidance. Subsequently, contrast injection via left brachial vein revealed that the left cephalic and axillary veins were well visualized at the same time the origin of the left subclavian vein was seen. Contrast was noted to flow inferiorly in the left mid-chest, prior to crossing the midline. Rapid dissipation of the contrast was noted at the time of cephalad flow suggesting confluence of venous drainage. Subsequent review of the pre-procedural MRI revealed a persistent left superior vena cava and absent right superior vena cava, not previously identified, in addition to the previously noted sinus of Valsalva aneurysm (Figs. 2–4). The initial misinterpretation of the cardiac MRI yields truth behind the adage “We find what we look for, and we look for what we know.”
Discussion Sinus of Valsalva aneurysm is a rare congenital anomaly, with a reported incidence of 0.1–3.5% of all congenital heart defects [1]. In our patient, there was no history consistent with trauma, endo-
Fig. 3. Coronal non-gated contrast-enhanced MRI shows an enlarged left superior vena cava communicating with a dilated coronary sinus (arrow) which empties into the right atrium (arrow head). Left atrium, LA; aortic arch (AA).
carditis, syphilis, or physical findings characteristic of Marfan’s syndrome. Associated congenital anomalies include bicuspid aortic valve, ventricular septal defects, and coarctation of the aorta. The incidence of persistent left superior vena cava (PLSVC) is approximately 0.5% in the general population. In the presence of other congenital heart disease, the frequency of PLSVC increases to 3–10% [2]. Although first recognized in 1862, absence of the right superior vena cava (RSVC) remains exceedingly rare [3, 4]. Two retrospective reviews of 14,279 cardiac catheterizations and post-mortem
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Isolated PLSVC is readily visualized through cineangiography and transesophageal echocardiography [14 –16]. Although cardiac magnetic resonance imaging was utilized primarily to further define the aneurysm, it helped readily identify multiple coexistent congenital anomalies. The utility of MRI in patients with aortic disease, congenital valvular disease and intracardiac shunts has been well described [17]. This is the first report of using MRI to define the complex findings seen in this patient. In light of the increased association of PLSVC with other congenital cardiac anomalies, the use of cardiac MRI may be warranted for the pre-operative evaluation of adult patients with congenital disease to identify confounding variables of surgical importance. References
Fig. 4. Coronal ECG gated T1 weighted MRI image shows a dilated aortic root and absence of the right superior vena cava.
examinations at two tertiary referral centers, in patients with known congenital heart disease and situs solitus, found only seventeen (0.1%) patients with PLSVC and absent right superior vena cava [5, 6]. Of note, the average age of these seventeen patients was 6.6 years, and only one patient older than 10 years of age (range, 14 days to 21 years). Associated congenital anomalies with absent RSVC have included Ebstein’s anomaly, tetralogy of Fallot, subaortic stenosis, total anomalous pulmonary venous return, and ventricular and atrial septal defects. Previous review has yielded less than 100 cases in the world-wide literature of patients with situs solitus, PLSVC, and absent RSVC [7]. Of these cases, only 15 were adults, eight of which had finding of either high-degree or complete atrioventricular block at the time of diagnosis [6, 8, 9]. The vast majority of reports are limited to pediatric cardiology, though when these anomalies are noted in the adult patient they may have unforeseen complications. Generally, PLSVC in adults has been reported in the literature as case reports when difficulties arise for those patients undergoing pulmonary artery catheter or transvenous pacemaker placement [10 –12]. These venous anatomic variants provide a significant hindrance to access of the right heart through catheterization. In our patient who was being considered for aortic root reconstruction, the surgical implications were important. In patients undergoing procedures requiring cardiopulmonary bypass, caval cannulation needs to be altered to allow for increased flow into the right atrium and customary retrograde cardioplegia should be avoided [13]. In addition, there is presumed “stretching of junctional tissue” which leads to increased arrhythmias [6].
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