Investigations for Coarctation of aorta

Investigations and brief pathophysiology of coarctation of aorta

1. Coarctation of Aorta

2. Pathophysiology Fetal hemodynamics –Least disturbed (only 10 % combined ventricular output transverses the aortic isthmus) After birth , the pathophysiology depends on :- Degree of obstruction Type of COA Rapidity of development of obstruction Status of ductus arteriosus State of collateral circulation Associated intracardiac lesion

3. Coarctation of aorta ->increases impedance of LVOT->Elevated systolic pressure in LV and Asc . Aorta:- Left ventricular myocardial hypertrophy Upper body systolic hypertension Systolic pressure gradient across the coarctation Myocardial hypertrophy normalizes myocardial wall stress and ventricular afterload and maintains normal ventricular function .

4. Perfusion to lower limb maintained via collaterals Patient remains asymptomatic for until complications of left ventricular hypertrophy ,degenerative aortic changes or chronic systemic hypertension occur.

5. Coarctation develops rapidly ->Rapidly increasing afterload->left ventricular failure . Manifestations of left ventricular failure:- Left ventricular systolic dysfunction Ventricular dilatation Mitral regurgitation Elevated left ventricular end-diastolic pressure Elevated atrial pressure Pulmonary venous congestion Potential for left to right atrial level shunting through foramen ovale Severe hypoperfusion of organs distal to coarctation:- Metabolic acidosis Oliguria Gut ischemia Cold constricted extremities

6. Ductus arteriosus wide open:- RV output provides lower body perfusion via the ductus , Sev . Hypoperfusion of lower body is avoided Acute Left ventricular decompensation depends upon the acuteness of ductal closure:- Rapid ductal closure ->LV fails , lower body hypoperfusion Gradual ductal closure-> Time for LV hypertrophy and Collateral formation.

7. Associated Intracardiac defects Commonly a VSD is present Due to VSD pulmonary artery pressure remains elevated for more prolonged period after birth. VSD + PDA-> Lower body perfusion maintained for longer period Due to fall in pulmonary vascular resistance and closure of PDA :- Lower body hypoperfusion occurs Increased systemic afterload due to coarctation + decreased PVR->Ventricular level left to right shunt increases ->LV failure due to volume overload + increased after load. Patients with VSD and COA always develop severe symptoms in neonatal period or in the early infancy.

8. Abnormalities in vascular physiology Systolic arterial hypertension:- Aortic obstruction Increased reactivity of arteriolar resistance vessels Reduced compliance of aortic wall Resetting of the baroreceptor reflex Increased plasma renin activity

9. ECG Standardization and speed :- 12 lead ECG , 25 MM/SEC , 1MM=0.1 MV RATE:- 300/LARGE BOXES , 1500/SMALL BOXES AXIS:- P WAVE PR INTERVAL QRS ST SEGEMENT T WAVES

10. Infants and neonates The electrocardiogram (ECG) usually shows right ventricular hypertrophy in the first few months of life, even with isolated coarctation. About two thirds of infants operated on in the first year of life have right ventricular hypertrophy or combined hypertrophy, and fewer than 25% have pure left ventricular hypertrophy.

11. ECG In the neonatal period , the ECG may reflect RVH rather than LVH.  This is because the right ventricle in-utero is the dominant ventricle, and through the PDA pumps blood to the descending aorta.  In Infancy ECG is generally normal

12. Childhood(1-14 yrs ) ECG shows predominantly left ventricular hypertrophy, with right ventricular hypertrophy present only when there is pulmonary hypertension with elevated pulmonary vascular resistance. ECG is normal in about one third of children. Adolescence (Beyond 14 Years) and Adult Life Left ventricular hypertrophy and features of left ventricular failure on ECG

13. In an infant the findings of left ventricular hypertrophy with strain pattern (ST SEGMENT DEPRESSION AND T WAVE INVERSION):- Strongly suggests the associated presence of aortic stenosis or endocardial fibroelastosis Older patients have findings of left ventricular hypertrophy usually without strain. Bicuspid aortic valve – Q wave of left precordial AR causing LVVO

14. Electrocardiogram Symptomatic (sick) neonate with pulmonary venous congestion- The QRS axis is rightward. tall p wave in lead 1 ( rt atrial) Right ventricular hypertrophy is manifested by a tall monophasic R wave in led V1 and deep S waves in left precordial leads.

15. 2. Coarctation after childhood The QRS axis is normal. Normal P wave in lead 2 . Left ventricular hypertrophy is suggested by deep S wave in V1 and tall R wave in v5 with low, flat, or inverted T waves in left precordial leads

16. Electrocardiography (ECG) showed sinus rhythm with features of extreme right axis deviation with absent left ventricular forces in leads V4 to V6 ( 20 DAY OLD TERM CHILD)

17. RIGHT VENTRICULAR HYPERTROPHY ECG Axis : RAD for the patients age Voltages : Tall R waves (greater than limits for patient’s age) in right-sided leads V4R and V1. Deep S waves (greater than limits for patient’s age) in left-sided leads V5 and V6. R/S ratio : Abnormal R/S ratio in favour of RVH. Increased R/S ratio (greater than upper limits for child’s age) in V1-2. R/S ratio < 1 in V6 (after one month of age). Abnormal T waves: Upright T waves in V1 and V4R in children 3 days to 6 years (provided that T waves are normal elsewhere, i.e. upright in V6). This is evidence alone of significant RVH. Abnormal Q waves : qR pattern in V1 (small Q wave, tall R wave) = highly specific for RVH. Dominant R wave in V1 (> 7mm tall or R/S ratio > 1). Dominant S wave in V5 or V6 (> 7mm deep or R/S ratio < 1). Right ventricular strain pattern = ST depression / T wave inversion in the right precordial (V1-4) and inferior (II, III, aVF ) leads.

18. R Wave Peak Time ( Intrinsicoid deflection ) The time from the onset of the earliest Q or R wave to the peak of the R wave in the lateral leads ( aVL , V5-6). Represents the time taken for excitation to spread from the endocardial to the epicardial surface of the left ventricle. R-wave peak time is said to be prolonged if > 45ms FOR Left LEADS AND >35 MS FOR RIGHT LEADS

19. COA IN 11 YRS FEMALE

20. CHEST XRAY VIEW EXPIRATORY OR INSPIRATORY MARKER LOCATION EXPOSURE CENTRALISATION ABDOMINAL SITUS BRONCHIAL SITUS CARDIAC POSITION CARDIAC APEX AORTIC ARCH sidedness CTR

21. X-ray In an infant with congestive heart failure :-X-RAY non specific except for cardiomegaly and pulmonary congestion. In asymptomatic infants and young children :- x-ray is normal. In children and adolescents heart is only mildly enlarged

22. The x-ray in symptomatic infants Pulmonary venous congestion with dilation of the right ventricle and the right and left atria Left ventricular size remains normal or nearly so

23. VIEW ROTATED FILM OVER EXPOSED ABDOMINAL SITUS-SOLITUS BRONCHUS SITUS-SOLITUS CARDIAC POSITION-LEVOPOSITION CARDIAC APEX-LEVOCARDIA CTR-0.7 RV TYPE APEX STRAIGHTENIG OF LEFT HEART BOR. PROMINENT PA SEGMENT FEATURES OF PVH AND PULMONARY EDEMA

24. CEPHALISATION KERLEY B CARDIOMEGALY 1 2 3 4

25. In children and young adults The post-coarctation descending thoracic aorta has a distinctive leftward convexity that is accompanied by dilation of the left subclavian artery .

26. 30 YRS FEMALE WITH COARCTATION LSCA AND ARCH DILA. COA POST. STENO DILA.

27. ADULT COARCTATION CHEST XRAY (35 YRS/MALE)

28. The  figure 3 sign  is seen in  aortic coarctation  and is formed by prestenotic dilatation of the  aortic arch  and left  subclavian artery , indentation at the coarctation site (also known as the "tuck"), and post-stenotic dilatation of the  descending aorta . FIGURE 3 SIGN

29. On barium studies of the esophagus in patients with aortic coarctation, a corresponding contour abnormality is demonstrated, referred to as the reverse figure 3 sign or E sign. REVERSE FIGURE 3 SIGN OR E SIGN

30. Notching of the ribs Classic radiologic sign of coarctation caused by collateral flow through dilated, tortuous, pulsatile posterior intercostal arteries. Rib notching seldom appears before age of 6 years ( 3 years, Kirklin ) Typical coarctation distal to the LSCA results in bilateral notching between the third and the eighth posterior ribs When the LSCA lumen is compromised - unilateral rib notching is confined to the right hemithorax Anomalous origin of the RSCA distal to the coarctation - unilateral notching is confined to the left

31. PA VIEW WELL CENTRALISED APPROPRIATE EXPOSURE ABDOMINAL SITUS-SOLITUS BRONCHUS SITUS-SOLITUS CARDIAC POSITION-LEVOPOSITION CARDIAC APEX-LEVOCARDIA CTR-0.55

32. COLLATERAL CIRCULATION RARE IN NEONATES DEVELOPS IN CHILDHOOD (>5YRS) Rib notching is caused by erosion of the inferior surfaces of posterior ribs by dilated and tortuous intercostal arteries First two are not involved as first and second intercostal arteries do not form collateral channels SEEN IN INF BORDER OF 3-6 (..9)RIBS RT SIDED RIB NOTCHING ONLY-? LT SIDED RIB NOTCHING ONLY- ?

33. Causes of U/L Rib Notching Neurofibromatosis Post classic BT shunt A-V malformation Left SCA origin stenosis Causes of B/L Rib notching COA IAA Multiple myeloma Osteogenesis imperfecta Osteoclastic malignancy SVC obstruction with venous collaterals

34. 2D ECHO

35. Echocardiogram Echo assessment is helpful in- Coarctation segment itself is visualised LV changes in coarctation – Size,cavity , thickness, systolic and diastolic function. Associated lesions- VSD, BAV,etc Supra-sternal notch window/ parasternal view with colour flow imaging is identifies the coarctation by a zone of localized accelerated flow Peak systolic velocity - reflects maximal systolic gradient Persistent high-velocity diastolic forward flow - indicates severity

36. ECHO IN COA SITE OF COA MORPHOLOGY OF COA COARCTATION SHELF SEVERITY OF COA PDA POST STENOTIC DILATATION / ANEURYSM GRADIENTS DISSECTION ARCH VESSELS AORTIC ARCH LV FUNCTION CORONARY ARTERIES ASSOCIATED ABNORMALITIES

37. ASSOCIATED ABNORMALITIES AORTIC VALVE MORPHOLOGY-BICUSPID VALVE LVOT EVALUATION VSD CONGENITAL MS /PARACHUTE MITRAL VALVE SUPRA MITRAL RING TGA SINGLE VENTRICLE AVSD DORV TAPVC/PAPVC

38. SUBCOSTAL VIEW

39. SUBCOSTAL VIEW

40. APICAL 4 CHAMBER VIEW

41. DOPPLER APICAL FOUR CHAMBER MITRAL

42. DOPPLER APICAL 4 CHAMBER TRICUSPID

43. APICAL 5 CHAMBER VIEW

44. DOPPLER APICAL 5 CHAMBER VIEW

45. DOPPLER APICAL 5 CHAMBER VIEW

46. PARASTERNAL LONG AXIS VIEW

47. PARASTERNAL LONG AXIS VIEW COLOR DOPPLER

48. PSAX LV

49. PSAX ARCH

50. PSAX ARCH DOPPLER

51. PSAX NO PDA

52. PSAX AORTIC LEVEL

53. NORMAL 7-11MM 16-19 /M2 7-11 MM 19-32/M2

54. DIASTOLIC TAILING –DIFF. PATIENT

55. AMATO TYPE 1

56. MEMBRANOUS COA

57. AMATO TYPE 2

58. AMATO TYPE 3

59. MRI and CT Currently the imaging modalities of choice for coarctation in patients beyond infancy Utility of MR/CT is in – Anatomy not clear in 2d echo –Better visualization of anatomy Assessing Coarctation morphology Assessment of ascending aorta / arch / DTA Collaterals Aneurysm formation Aortic Dissection Anomalous origin of arch vessels Airway assessment Vascular rings

60. MRI No radiation exposure Useful for post-interventional structural imaging for follow-up In advance stages to look for LV fibrosis Hemodynamic assessment Assessment of collateral flow Determine the significance of coarctation or recoarctation .

61. 8 MONTHS /FEMALE

62. 4 months/ female

63. Cardiac catheterization and aortography Once the standard for diagnosis in older patients - now secondary Now only indication is when balloon dilatation is indicated or any other intervention . A withdrawal gradient is present at rest across the coarctation- >20 mm Hg is significant

64. Gradient may be falsely assessed on cath due to Collateral flow may increase the pressure in the aorta distal to the coarctation Poorly contracting LV Low output state Multiple left sided obstructed lesions In such cases gradient is better measured by aortography CoA is evident by a decrease in diameter by 50 % Aortography also reveals any hypoplasia of the isthmus or arch, arrangement of the aortic arch branches, degree of collateral circulation, and presence of an aneurysm.

65. COA 11 YR /F CATH ANGIOGRAM