ABSTRACT ID : IRIA - 1068

COARCTATION OF AORTA BEFORE AND AFTER CORRECTION: THE

ROLE OF MDCT AORTOGRAPHY

BACKGROUNDDEFINITION :

Coarctation of aorta refers to a narrowing of the aortic lumen. It is a congenital condition whereby the aorta narrows in the area where the ductus arteriosus or ligamentum arteriosum (after regression) inserts [1].

It was first described by Morgagni at autopsy in 1760 [2].

INCIDENCE :

Aortic coarctation represents 5-7% of congenital heart disease. It has a male predominance (male-to-female ratio, 1.5:1) [2] and is known to occur in conjunction with a variety of conditions including Turner’s syndrome, Shone syndrome, ventricular septal defect, bicuspid aortic valve, and aneurysms of the circle of Willis [3].

Adult or juxtaductal form.

Is more common.

Usually localized.

Area of coarctation is just beyond the origin of LSCA at level of ductus.

Infantile form.

Long, tubular segment of narrowed aorta.

Diffuse type.

From just distal to innominate to level of ductus.

Intra cardiac defects (VSD,ASD, deformed mitral valve, PDA) present in 50% of diffuse type.

TYPES PRE DUCTAL POST DUCTAL

A. Ductal coarctation

B. Pre ductal coarctation

C. Post ductal Coarctation

PROGNOSIS : Non-treated aortic coarctation has a poor prognosis, with a

reported mortality of 75% by 46 years of age. Congestive heart failure is the most common cause of death (25.5% of cases), followed by aortic rupture (21%), complications of endocarditis (18%), and finally intracranial hemorrhage (11.5%) [4].

TREATMENT : The first surgical repair of aortic coarctation was performed by

Crafoord in 1944 [4]

Resection with primary end-to-end anastomosis[6], patch aortoplasty with prosthetic material homograft or autologous subclavian artery.

Bypass grafting with a prosthetic tube or autologous vascular grafts. The most common technique in current use is resection with end-to-end anastomosis.

Balloon dilation[5] with stent insertion for native aortic coarctation or recoarctation is being used increasingly as an alternative to surgery and, in some centers, has replaced surgery as the primary management strategy [7].

CASE REPORT We report here a case of 34 –year–old male, diagnosed with

arterial hypertension , Headache, blurring of vision and bilateral lower limb fatigueness x 1 year , with difficult control of blood pressure values under treatment with beta–blocker, ACE and diuretics. He had no history of cardiac problems or family history of hypertension. K/C/O DM since 1 year on irregular treatment.

The clinical examination showed :

Patient conscious , oriented and afebrile . Normal body development, a blood pressure of 200/120 mmHg in the right arm and 190/110 mmHg in the left arm, large pulsations in the suprasternal notch, normal heart sounds -60 bpm.. The radial pulses were palpable but feeble pulse was found at the palpation of the femoral arteries or distal to that level.

Systemic examination :

- CVS

- RS

- CNS

- PA

NAD

IMAGING FINDINGSCHEST X-RAY PA VIEW:

Show bilateral rib notching “Roesler sign” caused by pressure from intercostal blood vessels and “3 sign”.

INVESTIGATIONS

ECG- NSR / NO significant ST –T changes.

USG DOPPLER: Parvus tardus flow in aorta and renal arteries

Echo – concentric LVH, bicuspid aortic valve, dilated ascending aorta with suspicious narrowing at descending aorta, normal LV function.

“Following which patient was suspected coarctation of aorta and hence subjected to CT

aortogram”

CT AORTOGRAM-PROTOCOL

MDCT angiography examination was performed with a 128-slice GE Optima CT660 machine, plain and post contrast images extending from C5 level till abdominal aortic bifurcation were acquired during a single breath hold.

The imaging data was acquired during an intravenous injection of iodinated contrast agent (1.5ml/kg) at a rate of 5 ml/s.

The scanning delay was determined with a bolus tracking technique. For MIP and three dimensional image reconstruction, the volumetric CT data sets were processed on a separate workstation with multiplanar reformatting, curved planar reformatting, maximum intensity projection, and volume rendering.

MDCT ANGIOGRAPHY

Focal severe narrowing (coarctation) of distal isthmic part of aorta is noted ~2.0 cm distal to the left subclavian artery ostium. Lumen calibre at the site of coarctation is ~2.5 mm for length.

COARCTATION OF AORTA

DESCENDING SCAPULAR ARTEIES

THORACIC AND ABDOMINAL COLLATERALS

Bilateral subclavian arteries --> thyrocervical and costocervical trunks-->thoraco acromial and descending scapular arteries-->posterior intercostal arteries-->DTA.

Bilateral subclavian arteries -->internal mammary arteries(7mm) -->superior epigastric arteries -->inferior epigastric arteries -->external iliac arteries.

POSTERIOR INTERCOSTAL ARTERIES

LATERAL THORACIC ARTERY

SUPERIOR EPIGASTRIC ARTERIES

Celiac axis, superior and inferior mesenteric arteries are normal in opacification.Right renal artery and duplicated left renal arteries are normal in caliber and opacification.

Both lungs are normal ,no evidence of pleural/pericardial effusion.No evidence of mediastinal lymphadenopathy.Liver, spleen ,kidney and visualized bowel loops are normal.

CELIAC AXIS

Features of severe post ductal coarctation of aorta with dilatation of left subclavian artery and post stenotic DTA.

Extensive collaterals from bilateral subclavian and axillary arteries reconstituting the thoraco-abdominal aorta and iliac arteries.

Mild left ventricular hypertrophy noted. No intra cardiac abnormality on CT.

SMA

DIFFERENTIAL DIAGNOSIS Pseudocoarctation of the aorta is a very rare anomaly

characterised by kinking or buckling, of the aorta without  a pressure gradient across the lesion.

Takayasu`s arteritis Various types of vasculitis produce aneurysms in many portions of the aorta and its branches, but Takayasu arteritis is the only type of aortitis that produces stenosis in the thoracic aorta

Intrerrupted aortic arch (IAA) is defined as a complete luminal and anatomic discontinuity between the ascending and descending aorta, as described by Steidele in 1778.

Coarctation of the abdominal aorta, also known as middle aortic syndrome or midaortic dysplastic syndrome, is a clinical condition caused by segmental narrowing of the abdominal or distal descending thoracic aorta secondary either to a congenital anomaly in the development of the abdominal aorta or to one of several acquired conditions.

POSTOPERATIVE IMAGING

PROCEDURE :Bypass grafting of coarctation of aorta (16mm polyester graft ) - End to Side anastomosis

PA VIEW AP VIEW

PREOP CT IMAGING POST OP CT IMAGING

Significant reduction in the collateral of internal mammary arteries , lateral thoracic arteries and Intercostal arteries

CONCLUSION MDCT aortography allows excellent evaluation mapping of the aortic narrowing,

associated cardio-vascular anomalies before and after surgery. Three-dimensional and MIP reconstructions provides angiographic-like images that enable precise measurements of the stenosis length and With its high spatial resolution and isotropic and volumetric information, multidetector CT performed with or without an ECG-gated technique allows accurate and fast noninvasive characterization of aortic pathologic conditions.

Identification of collateral circulation is of importance before surgery to avoid ischemic medullary injury. In our study had collateral vessel formation, and the origin and course of collateral vessels were very well displayed with three-dimensional MDCT angiography.

Compared with MR angiography, MDCT angiography has the advantage of the ability to acquire high spatial resolution in a shorter acquisition time. In addition, volume rendered and multiplanar reconstructions are better for MDCT angiography data display than MRI.

It is an alternative tool helpful in establishing the primary diagnosis, defining anatomic landmarks and relationships, and identifying associated vascular and cardiac anomalies and is an adjunct in diagnosis of complications and detection of disease progression during follow-up.

Recently, time-resolved PC-MRI with velocity encoding along all three flow directions and three-dimensional (3D) anatomic coverage (also termed ‘4D flow MRI’ ) has been developed and applied for the evaluation of cardiovascular hemodynamics in multiple regions of the human body. Advanced parallel imaging techniques such as k-t GRAPPA, have resulted in reasonable overall scan times, e.g., 8-12 minutes for 4D flow MRI of the aorta and 10-20 minutes for whole heart coverage. 

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