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SYSTEMIC VENOUS ANOMALIES. Dr Ranjith MP Senior Resident Department of Cardiology Government Medical college Kozhikode. EMBRYOLOGY. Heart- First organ to start functioning & the 1st organ to fully develop in the fetus First seen as 2 endothelial heart tube. 21 days - heart tube forms
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SYSTEMIC VENOUS ANOMALIES Dr Ranjith MP Senior Resident Department of Cardiology Government Medical college Kozhikode
EMBRYOLOGY • Heart- First organ to start functioning & the 1st organ to fully develop in the fetus • First seen as 2 endothelial heart tube • 21 days - heart tube forms • 23 days- heart beats • Week 4 - cardiac loop forms • Week 7 - heart fully developed
EMBRYOLOGY • Changes in the sinoatrial orifice
EMBRYOLOGY • In the fifth week, three pairs of major veins can be distinguished: • The vitelline veins (omphalomesenteric veins) • carrying blood from the yolk sac to the sinus venosus • The umbilical veins • originating in the chorionic villi, carrying oxygenated blood to the embryo • The cardinal veins • draining the body of the embryo proper.
EMBRYOLOGY Main components of the venous and arterial systems in a 4-mm embryo (end of the fourth week).
EMBRYOLOGY • Cardinal Veins • The anterior cardinal veins drains the cephalic part of the embryo • The posterior cardinal veins drains the rest of the embryo • The anterior and posterior veins join before entering the sinus horn and form the short common cardinal veins (ducts of Cuvier) • During the fourth week, the cardinal veins form a symmetrical system
EMBRYOLOGY • Development of veins draining upper part of body • Ducts of Cuvier • Subclavian veins • Transverse anastomosis • Superior venacava • Right Brachiocephalic vein • Left Brachiocephalic vein • Internal Jugular vein External jugular vein arise as secondary channel
EMBRYOLOGY • Development of Inferior venacava B. Vitelline and umbulical vein broken in to numerous channel C. Formation of Hepatocardiac channel D. Formation of Common hepatic vein & Ductus venosus
EMBRYOLOGY • Development of Inferior venacava • During the fifth to the seventh week a number of additional veins are formed: 1.The subcardinal veins, mainly drain the kidneys 2.The sacrocardinal veins, drain the lower extremities 3.The supracardinal veins, drain the body wall by way of the intercostal veins, taking over the functions of the posterior cardinal veins
EMBRYOLOGY • Development of Inferior venacava • Green- Subcardinal • Red- Supracardinal • Yellow- Subcardinal-hepatocardinal anastomosis • Blue- Hepatocardiac channel • White- Supracardinal-Subcardinal anastomosis
EMBRYOLOGY • Development of Inferior venacava • The anastomosis between the subcardinal veins forms the left renal vein • The left subcardinal vein disappears, and only its distal portion remains as the left gonadal vein • The right subcardinal vein becomes the main drainage channel and develops into the renal segment of the inferior vena cava
EMBRYOLOGY • Development of Inferior venacava • The anastomosis between the sacrocardinal veins forms the left common iliac vein • The right sacrocardinal vein becomes the sacrocardinal segment of the inferior vena cava • When the renal segment of the IVC connects with the hepatic segment, the IVC (consisting of hepatic, renal, and sacrocardinal segments) is complete
EMBRYOLOGY • Development of Azygos veins
EMBRYOLOGY • Development of Azygos veins • The 4thto 11th right intercostal veins empty into the right supracardinal vein, which together with a portion of the posterior cardinal vein forms the azygos vein • On the left the 4th to 7th intercostal veins enter into the left supracardinal vein, and the left supracardinal vein, then known as the hemiazygos vein, empties into the azygos vein
Anomalies of the SVC • Bilateral SVC with normal drainage • Bilateral SVC with an Unroofed Coronary Sinus • Absent Right SVC in Visceroatrial Situs Solitus • Left Atrial or Biatrial Drainage of Right SVC • Retroaortic Innominate Vein
Bilateral Superior Venae Cavae with Normal Drainage to the Right Atrium • Result from failure of the left anterior and left common cardinal veins to involute • The incidence is 0.3% • LSVC drains into RA through CS in 92% -in to LA by unroofed CS in 8%
Bilateral Superior Venae Cavae with Normal Drainage to the Right Atrium superior vena cava A=right B=left C: communicating vein, D: aorta E: pulmonary trunk. A: coronary sinus (enlarged) B: aorta, C: inferior vena cava D: left pulmonary veins
Bilateral Superior Venae Cavae with Normal Drainage to the Right Atrium • Anatomy • The size of the LSVC varies • left innominate vein may be present in 60% • The LSVC starts at the junction of the left jugular and left subclavian veins • Joins the CS in the posterior left AV groove
Bilateral Superior Venae Cavae with Normal Drainage to the Right Atrium • Clinical Manifestations • Physiology is usually normal & no clinical manifestations • Enlargement of the CS may interfere with blood flow from the LA into the LV • An increase in the magnitude of the Lt to Rt shunt at the atrial level was found in patients with secundum ASD persistent LSVC, and dilated coronary sinus
Bilateral SVC to Right AtriumDiagnostic Features • Chest Xray • Shadow along the Lt upper border of the mediastinum • 2D echo 100% specificity & 96% sensitivity • A dilated CS is often the first clue to the diagnosis • Imaged from the suprasternal notch or from the high left parasternal/subclavicular windows • Presence & size of the Lt innominate vein can also be imaged
Bilateral Superior Venae Cavae with Normal Drainage to the Right Atrium • 2D echo • There is an inverse relationship between the caliber of the LSVC and the left innominate vein • May confuse with a TAPVC or PAPVC, left superior intercostal vein, and a levoatrialcardinal vein • In contrast to a LSVC to an intact coronary sinus, however, the direction of blood flow in these veins is expected to be into the left innominate vein
Bilateral SVC to Right AtriumDiagnostic Features A: Subcostal long-axis view B: Parasternal long-axis view C: The LSVC is seen anterior to LPA in the parasternal short-axis view D: The drainage of the LSVC to the CS and to RA seen in parasternal sagittal view
Bilateral SVC to Right AtriumDiagnostic Features • Cardiac catheterization • LSVC can be suspected by the presence of higher-than-expected CS oxygen saturation • The LSVC can be approached either through the right SVC (when the innominate vein is present) or through the coronary sinus • Left innominate vein angiography with balloon occlusion proximal to the injection site is diagnostic
Bilateral Superior Venae Cavae with Normal Drainage to the Right Atrium • Treatment- No treatment is necessary for an isolated LSVC to an intact coronary sinus
Bilateral SVC with an Unroofed Coronary Sinus • Anatomy • Common wall between the LA & CS absent • Persistent LSVC drains into the left atrium • In patients with a normal inter atrial septum, the orifice of the unroofed CS will function as an interatrial communication • Visceral heterotaxy with asplenia exhibits the highest incidence of bilateral SVCs with a completely unroofed coronary sinus
Bilateral SVC with an Unroofed Coronary Sinus • Clinical Manifestations • Most patients have a large CS ostium that functions as an interatrial communication (Raghib syndrome) • Cyanosis and left-to-right shunting • In most patients, the arterial oxygen saturation ranges between 85% and 95% • They are at risk for complications of right-to-left shunting, including paradoxical emboli, brain abscess, strokes, and death
Bilateral SVC with an Unroofed Coronary Sinus • Clinical Manifestations • In patients with atretic CS ostium the only clinical manifestations are cyanosis and its sequelae • When right atrial outflow stenosis or atresia coexists with a persistent LSVC to an unroofed coronary sinus, the shunt is exclusively from right to left
Bilateral SVC with an Unroofed Coronary SinusDiagnostic Features • ECG • Axis of the P wave may be abnormal in patients with heterotaxy syndrome • Chest Xray • Shadow along the Lt upper border of the mediastinum
Bilateral SVC with an Unroofed Coronary SinusDiagnostic Features • Echocardiography-the definitive imaging modality • The posterior left AV groove is examined in detail to ascertain the extent of deficiency of the CS septum • When the CS septum is completely unroofed, the LSVC terminates in the upper Lt posterior corner of the LA between the LUPV posteriorly and the LA appendage anteriorly • Color Doppler or contrast injection demonstrates flow from the LSVC into LA • Cardiac catheterization • Step-down in oxygen saturation between PV & LA • LSVC selective angiocardiography
Bilateral SVC with an Unroofed Coronary SinusDiagnostic Features B.MR image in a coronal plane shows complete unroofing of the CS. LSVC connects to the roof of the LA and the CS opening functions as a LA septal defect (Raghib defect) A. Injection into the LSVC opacifies CS and shunting of contrast medium into the LA thorough the defect
Bilateral SVC with an Unroofed Coronary SinusTreatment • Repair is done to avoid complications of cyanosis • If the LSVC is relatively small and there is an adequate-sized left innominate vein, the LSVC can be ligated and the interatrial communication closed • In the absence of an adequate-sized bridging left innominate vein, the coronary sinus is reroofed • Baffling the LSVC along the posterior wall of the LA in to RA • ASD device closure of CS defect
Absent Right SVC in Visceroatrial Situs Solitus • 0.07% to 0.13% of cardiovascular malformations • Characterized by persistence of the LSVC draining to the RA via the CS and by left-sided azygos vein draining into the LSVC • Less constant features • Additional cardiovascular malformations (46%) • Rhythm abnormalities (35%)
Absent Right SVC in Visceroatrial Situs Solitus • Clinical Manifestations • Usually asymptomatic • Rhythm disturbances • Atrioventricular block • sinoatrial node dysfunction • ventricular tachycardia • Left and right bundle-branch block • supraventricular tachycardia • Sudden death
Absent Right SVC in Visceroatrial Situs Solitus • Diagnostic Features • Issues that make diagnosis important are • Implantation of transvenous pacemaker • Placement of a pulmonary artery catheter for intraoperative or postoperative monitoring without the use of fluoroscopy • Systemic venous cannulation for extracorporeal membrane oxygenation • Systemic venous cannulation for cardiopulmonary bypass • Partial or total cavopulmonary anastomosis • Orthotopic heart transplantation and endomyocardial biopsies • Diagnosis established by echocardiography, MRI, CT, or angiography
Absent Right SVC in Visceroatrial Situs Solitus • Treatment No intervention is indicated when the physiology is normal Venogram in the innominate vein in a patient with absence of the right SVC and persistence of the LSVC, which drains into the RA via the CS
Left Atrial or Biatrial Drainage of Right SVC • It represents a sinus venosus defect of the SVC type in association with atresia of the right SVC orifice • It results from the deficiency of the common wall between the SVC & RUPV • This defect unroofs the RUPV & its branches into the right SVC • The unroofed RUPV then drains into the SVC, and its LA orifice becomes the interatrial communication
Left Atrial or Biatrial Drainage of Right SVC • Clinical Manifestations • Cyanosis is the dominant clinical feature • symptoms may not develop until late childhood or adolescence • The risks of Rt to Lt shunt sequelae increase with age • Diagnosis • Demonstration of a common entrance site of Rt SVC and the RUPV in the roof of the LA by echo or angio
Left Atrial or Biatrial Drainage of Right SVC • Treatment • The right SVC flow is surgically diverted into the RA • In the past, this was done by creating an ASD and redirecting SVC flow into RA and the pulmonary blood flow into LA • Preferred surgical approach is transection of the right SVC above the entrance of the RUPV and anastomosis of the transected caval end to the RA appendage
Retroaortic Innominate Vein • First reported in 1888, and 62 cases have been reported to date • Also known as postaortic innominate vein • Anatomy • Characterized by an abnormal position of the left innominate vein behind the ascending aorta • Normal course of the left innominate vein is from left to right, anterior to the aortic arch • In RAIV it is horizontally behind the ascending aorta to reach the SVC below the insertion of the azygos vein
Retroaortic Innominate Vein • Most patients have associated cardiac malformations • Embryology • Results from failure of the high transverse capillary plexus that forms the left innominate vein to develop • In such circumstance, venous blood returning from the Lt side of the head and the Lt arm may drain through a lower venous plexus that communicates between the Lt & Rt anterior cardinal veins • This lower venous plexus then forms the RAIV
Retroaortic Innominate Vein A: Diagram showing a RAIV associated with a . right aortic arch in a patient with TOF, RSVC B: Gadolinium-enhanced MR angiogram showing a . retroaortic innominate vein
Retroaortic Innominate Vein • Clinical Manifestations • Asymptomatic • Surgical importance • Diagnosis • Echo, angio or MRI • Accurate echocardiographic diagnosis is based on tracking the left innominate vein from its origin through its retroaortic course to the SVC • Cine MRI and three-dimensional MRA are particularly useful in depicting the anatomy • Treatment-No treatment is necessary
Levoatrialcardinal vein • First described Edwards and DuShane in 1950 as a vein connecting the rt. SVC and LA • Remnant of an early embryonic venous channel that connects the splanchnic plexus of the lungs with the cardinal system • In the mature heart, it connects the LA or a PV with the Lt innominate or other systemic veins • Typically It is associated with severe LA outlet obstruction
Levoatrialcardinal vein • The diagnosis can be established by following the anomalous vein from its origin to its termination in a systemic vein • Unlike persistent LSVC that courses anterior to the left pulmonary artery, a levoatrialcardinal vein typically ascends posterior to it • It complicates the completion of a Fontan-type operation Levoatriocardinal vein in a patient with cortriatriatum. It drains the proximal chamber of the LA to the innominate vein
Levoatrialcardinal vein Multiplanar reformated image showing a levoatriocardinal vein (arrow) connecting an anomalous vein draining into the IVC and a pulmonary vein draining in to LA
Anomalies of the Coronary Sinus • Coronary Sinus Defect and Unroofed CS • Coronary Sinus Orifice Atresia • Coronary Sinus Aneurysm or Diverticulum