Introduction:
Persistent left superior vena cava (PLSVC) is the most common venous abnormality of the thorax, but is found in less than 0.5% of the general population and about 4% of patients with congenital heart disease.[1] Persistent left superior vena cava (PLSVC) may drain either into right atrium or left atrium of which drainage into right atrium is common. Etiology being Failure of regression of left anterior and common cardinal veins and left sinus horn
Persistent left superior vena cava (PLSVC) is associated with many other congenital anomalies but in our patient it is associated with abdominal aortic stenosis with multiple arterial collaterals.
Case Report
A 44 years old female with a history of hypertension and hypothyroidism and presented to the emergency room with shortness of breath, chest pain and palpitations. The chest pain was constant but increased in intensity with movement. It was non-exertional and was not relieved with nitroglycerin. Her serial troponin values were all negative. On examination the BP in right upper limb was 210/100 and in left upper limb was 160/90. Femoral pulses were feeble and distal pulses were absent in bilateral lower limbs.
So a CT angiography of arch of aorta and abdominal aorta are performed , after injection of non –ionic contrast through left antecubital vein.These images were interpreted with MIP, SSD and volume rendering.
Arterial System: The study revealed evidence of eccentric soft plaque in distal thoracic aorta causing insignificant stenosis. Aortic arch and proximal thoracic aorta were normal in course and calibre. The study also revealed evidence of calcified plaque in distal thoracic aorta and proximal abdominal aorta causing insignificant stenosis.
There was evidence of short segment tight stenosis of aorta at level of D12-L1(Figure1) causing area stenosis of 84% and another long segment stenosis of approximate length 4cm causing complete stenosis of aorta at L2-L3 disc level to L3-L4 disc level.
There were multiple collaterals arising from celiac, superior mesenteric and inferior mesenteric arteries supplying distal segment of abdominal aorta and its bifurcation into iliac arteries. Branches of aorta were normal in calibre.
Venous system revealed persistent left cardinal vein persisting as Persistent left superior vena cava (PLSVC) giving a left long collateral venous channel upto D12 crossing the midline and joining the right azygous (Figure2) which drained into SVC. Persistent left superior vena cava (PLSVC) drained into right atrium. The right superior vena cava (SVC) was presented normally. Pulmonary venous system was normal
The diagnosis of Persistent left superior vena cava (PLSVC) was made because normally, at the level of the left main bronchus, there is only one vessel — the left superior pulmonary vein — located ventral to the bronchus. In PLSVC, two vessels — the normal left superior pulmonary vein and the left SVC — are present.
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Fig 1: Tight stenosis of aorta at level of D12-L1 and long segment
stenosiss at L2-L4
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Fig 2: Persistent Left Superior Vena Cava (Plsvc) Giving A Left Long Collateral Venous
Channel Upto D12 (Figure3)Crossing The Midline And Joining The Right Azygous |
Discussion:
Aortitis is the all-encompassing term ascribed to inflammation of the aorta. The most common causes of aortitis are the large-vessel vasculitides, giant cell arteritis (GCA) and Takayasu arteritis, although it also is associated with several other rheumatologic diseases. Infectious aortitis is a rare but potentially life-threatening disorder. Although most cases of aortitis are noninfectious in nature, the possibility of an infectious cause must always be considered because treatment strategies for infectious and noninfectious aortitis diverge widely. A number of organisms have been associated with infectious aortitis, most commonly the Salmonella and Staphylococcalspecies, along with Streptococcus pneumonia.[2,3] In most cases of bacterial aortitis, a segment of the aortic wall with preexisting pathology such as an atherosclerotic plaque or aneurysm sac is seeded by bacteria via the vasa vasorum.[2,3]
In some cases, aortitis is an incidental finding at the time of histopathological examination after surgery for aortic aneurysm. Because the clinical presentation of aortitis is highly variable, the cardiovascular clinician must have a high index of suspicion to establish an accurate diagnosis of this disorder in a timely fashion.
Abdominal aortic stenosis (AAS) refers to abnormal narrowing of the aorta anywhere along its course in the abdomen. The aorta enters the abdomen through the thoracic hiatus at the level of the 12th thoracic vertebra in front of the spinal cord and terminates as the right and left iliac arteries. Stenosis can result from congenital or acquired lesions. AAS produces a bottle neck effect, where there is hypertension above the lesion and hypotension below and can often be diagnosed based on the difference in blood pressure between the upper and lower extremities.
Persistent left superior vena cava
During the fourth week of intrauterine life, the cardinal veins form a symmetrical system, draining blood from the embryo proper to the heart. On both sides, the anterior cardinal vein, which drains the cephalic part of the embryo, and the posterior cardinal vein, which drains the remaining part of the body, join together to form a short common cardinal vein before entering the sinus horn.[4] In normal development, the SVC is developed on the right side by a portion of the right anterior cardinal vein and the corresponding common cardinal vein. On the left side, part of the left anterior cardinal vein regresses and obliterates to form the ligament of the left vena cava. The left common cardinal vein and the left horn of the sinus venosus persist as coronary sinus. Blood from the left side is channelled to the right by the anastomosis between the two anterior cardinal veins, which eventually develop into the left brachiocephalic vein around the eighth week of gestation.
Analogous to the right side, the left SVC develops owing to persistence of the left anterior cardinal vein and left common cardinal vein. Although the majority of patients with PLSVC are asymptomatic and are only discovered incidentally, this condition can present technical difficulties during intravascular procedures such as Swan–Ganz catheterisation and insertion of pacing systems or during cardiac surgery.[5] In addition, PLSVC may predispose the heart to arrhythmia owing to the close proximity of the dilated coronary sinus to the final position of the left-sided primitive pacemaking tissue.[6] Singular left SVC without a right SVC is rare. Most cases of PLSVC are presented as part of double SVC, as in our case. The PLSVC drains into the coronary sinus and then into the right atrium in ,90% of cases, which are often asymptomatic and haemodynamically insignificant. However, 10% of PLSVC cases connect to the left atrium, causing right-to-left shunt.[7] In rare instances, PLSVC forms a connection to the left atrium via a communication between the coronary sinus and left atrium. This cardiac defect is often called ‘‘unroofed coronary sinus’’ and it has a particularly strong association with PLSVC. Any right-to-left shunt, including unroofed coronary sinus, predisposes venous emboli to bypass the pulmonary circulation and gain access to the systemic circulation, resulting in paradoxical embolism.
Other than direct observation of the vessel, there are some radiological clues that can point to the existence of PLSVC, including (i) an enlarged and densely opaque coronary sinus on CT when intravenous contrast is injected from the left arm, (ii) the presence of focal mediastinal widening superior to the left side of the aortic knob on chest radiography and (iii) the aberrant course of the intravenous catheter approaching the left atrium from the left arm.[8]
References
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- Foote EA, Postier RG, Greenfield RA, Bronze MS. Infectious aortitis.
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- Virmani R, Burke A. Nonatherosclerotic diseases of the aorta and
miscellaneous disease of the main pulmonary arteries and large veins. In:
Silver M, Gotlieb A, Schoen F, eds. Cardiovascular Pathology. 3rd ed.
Philadelphia, Pa: Churchill Livingstone; 2001. PP107–137.
- Sadler TW. Langman’s medical embryology. 7th edn. Baltimore, MD: Williams and Wilkins, 1995.
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- Adluri K, Parmar JM. Persistent left superior vena cava – an anomaly to remember.
Br J Cardiol 2003;10:207–10
- Morgan DR, Hanratty CG, Dixon LJ, Trimble M, O’Keeffe DB. Anomalies of cardiac venous drainage associated with abnormalities of cardiac conduction system.
Europace 2002;4:281–7
- Burney K, Young H, Barnard SA, McCoubrie P, Darby M. CT appearances of congential and acquired abnormalities of the superior vena cava.
Clin Radiol 2007;62:837–42.
- Demos TC, Posniak HV, Pierce KL, Olson MC, Muscato M. Venous anomalies of the thorax.
AJR Am J Roentgenol 2004;182:1139–50.
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