COARCTATION OF AORTA MANAGEMENT

Dr. vikas

Deptt of ctvs, pgimer, chandigarh

SURGICAL MILESTONES AND GENERAL CONSIDERATIONS

SURGICAL MILESTONES

SURGICAL PROCEDURE

AUTHOR YEAR COUNTRY

Resection with end to end anastomosis

Crafoord and Nylin

1944 Sweden

Interposition graft Gross 1951 USA

Patch augmentation Vosschulte 1957 Germany

Subclavian flap aortoplasty Waldhausen and Nahrwold

1966 USA

Resection with extended end to end anast.

Amato 1977 USA

Surgical techniques General considerations

2 arterial lines: one in the right radial artery, another in femoral or umbilical artery.

Ambient temperature in the operating room.

Heating- cooling blanket. In neonates and young infants, temperature maintained near 35oC and in older patients, 33oC to 34oC

General considerations (ctd.)

Left posterolateral thoracotomy through the 4th Intercostal space

The proximal hypertension should not be treated vigorously.

General considerations (ctd.)

Upper lobe of left lung retracted anteriorly, medially and inferiorly

Pleura overlying isthmus is opened and extended superiorly to LSCA and inferiorly to the level of 3rd and 4th IC arteries.

General considerations (ctd.)

Distal arch, descending aorta, ductus, LCCA, LSCA dissected ,

Dissection plane should remain just superficial to the vascular adventitia to avoid injury to nerves, thoracic duct and other major lymphatics.

Intercostal arteries

Ideally, no Intercostal artery should be sacrificed.

In infants, gently placed small metal clips

Older patients may require tourniquets or small clamps

May be dilated, aneurysmal.

If ligated, should be away from Aorta (since origin is the area of greatest weakness)

PDA

Doubly ligated and divided

Preserved in small neonates with borderline small ventricle

General considerations (ctd.)

After stabilization, the gradient across the repaired segment is measure

< 10 mm Hg: acceptable >10 but <20 mm Hg: 1. no technical error possible, gradients are

because of arch morphology: Accept it 2. morphology adequate, but technical error

possible: revision > 20 mm Hg: un-acceptable

General considerations (ctd.)

If anastomosis appears

under tension,

few superficial stitches are passed through the adventitia of distal aorta and the aorta is pulled up towards the arch. These sutures are tethered to the nearby structures.

SPECIFIC SURGICAL TECHNIQUES

RESECTION AND END TO END ANASTOMOSIS A curved side biting

clamp for distal arch including the left subclavian artery

Angled, vascular cross clamp for descending aorta 1.5 cm below ductus insertion

Second assistant holds the two clamps 2 cm apart

Resection and End-to-End Anastomosis (ctd.) Entire posterior suture

line is performed before the clamps are approximated

Interrupted everting horizontal mattress sutures anteriorly

Resection and End-to-End Anastomosis - Concern: Relatively high recoarctation rate

(10% to 86%) in age group <1 year: 1. ductal tissue 2. lack of growth at suture line 3. hypoplastic transverse arch use of silk suture

Difficult in older patients: Arch and DTA ‘fixed’ and difficult to mobilize.

Resection and End-to-End Anastomosis - Advantages Complete removal of ductal tissue No prosthetic material Its modifications ( Extended resection and

anastomosis or resection-anastomosis with reverse subclavian flap) used in management of distal arch hypoplasia

RESECTION WITH EXTENDED END-TO-END ANASTOMOSIS Amato reported 4 infants with hypoplastic

arch in ATS, 1977. In 1986, Lansman reported a series of 17

infants who had resection with extended end-to-end anastomosis. (proximal clamp between the IA and LCCA

Elliot (ATS 1987) modification with a single clamp to occlude the LSCA, LCCA, and even part of IA (RADICALLY EXTENDED END-TO-END ANASTOMOSIS)

Resection with extended end-to-end anastomosis (ctd) Descending aorta is

extensively mobilized (usually first three sets of Intercostal vessels are ligated and divided)

Entire Coarct segment and ductus are excised

Incision on the inferior surface of the transverse arch.

Extended Resection and end to end anastomosis

Extended Resection and end to end anastomosis

Resection with extended end-to-end anastomosis (Advantages) All the coarctation tissue with uncertain potential for

future growth is completely resected Left subclavian artery is preserved Procedure addresses and corrects hypoplasia of the

transverse arch, the distal aortic arch, and the aortic isthmus.

No prosthetic material Limits the potential for aneurysm formation Preserves normal vascular anatomy Paraplegia has not been reported as complication

Hypoplastic arch and extended resection - Reports of growth of a hypoplastic arch with

standard end-to-end anastomosis ( Brower et al, JTCVS 1992) and

subclavian flap aortoplasty (Myers, ATS 1992)

- Some surgeons feel that extended arch repair should be reserved for infants with transverse aortic arch to ascending aorta diameter ratio of less than 0.25

- Some recommend extended resection for all infants under 2 years of age

PROSTHETIC PATCH AORTOPLASTY

Vosschulte in 1957(Thorax ; 1961) described “isthmusplastic” procedure that developed into the prosthetic patch aortoplasty

Prosthetic patch aortoplasty (ctd.)

Aorta incised longitudinally through the site of Coarctation

Elliptical patch of PTFE with the widest portion at the level of the aortic constriction

Advantages over simple resection with end-to-end anastomosis Avoids extensive dissection Collateral vessels are all preserved and do

not require ligation and division Anterior suture line, easy control of bleeding Allows simultaneous enlargement of the

isthmic hypoplasia Tension free anastomosis Easy to perform, short clamp time Posterior aortic wall will grow

Prosthetic patch aortoplasty (ctd.)

Resection of the coarctation ridge is no longer performed

Recommended for children older than 2 years and younger than 16 years of age

( higher incidence of recoarctation if <1 year of age and aneurysm formation if > 16 years of age)

Prosthetic patch aortoplastyDisadvantages Prosthetic material Ductal tissue left Aneurysm formation

PROSTHETIC INTERPOSTION GRAFT First described by Robert Gross in 1951. He

used aortic homograft (Ann Surg, 1951)

In 1960, Morris, Cooley, DeBakey and Crawford described use of Dacron prosthetic interposition graft 3% of their 171 patients (JTCVS, 1960)

Prosthetic interposition graft

Recommendation for prosthetic interposition graft Age > 16 years Associated aneurysm Complex long segment coarctation Recurrent coarctation If anastomosis appears under tension Thinned aortic wall in post stenotic dilatation

Disadvantages of interposition graft

Size discrepancy in growing child Longer aortic cross clamp time to perform 2

circular anastomoses

SUBCLAVIAN FLAPAORTOPLASTY Introduced by

Waldhausen and Nahrwold (JTCVS, 1966)

Successful coarctation repair was reported in three patients aged 4 months, 6 months and 3 years.

Subclavian flap aortoplasty (ctd.)

Aorta clamped proximal to LSCA

LSCA ligated distally Opened along its lateral

margin Incision extended

through the isthmus, Coarct site into the area of poststenotic dilatation.

Subclavian flap aortoplasty (ctd.)

‘flap’ sutured in place, creating a ‘roof’ over the area of previous Coarct

Subclavian flap aortoplasty (ctd.)

LIGATION OF VERTEBRAL ARTERY: leaving it intact provides collateral circulation to the arm but may possibly cause subclavian steal syndrome as the child grows.

If possible, LIMA and the Thyrocervical trunk are left

intact to provide collateral circulation to the arm (but sacrificed if more length is needed)

Short incision across the Coarct / short flap leads to restenosis at a later date

Advantages of Subclavian flap aortoplasty Simplicity Short cross-clamp time Avoidance of prosthetic material Easy anastomotic haemostatic control, Anastomotic growth owing to the use of an

autogenous noncircumferential flap.

Disadvantages

Left arm ischemia in older children ( Geiss D, JTCVS 1980; Wells WJ, ATS 2000)

Concern for long term growth and function in the left upper limb. (Todds, JTCVS 1983)

Recoarctation ( ranging up to 42% in some series)

Variations of SC flap technique

REVERSED SUBCLAVIAN FLAP:

Described by Hart and Waldhausen for repair of coarctation proximal to the left subclavian artery (ATS 1983)

Variations of SC flap technique (ctd)Amato technique Alternative to reverse

subclavian flap aortoplasty for distal arch hypoplasia

Bases of left common carotid artery and the subclavian artery are sutured together

Variations of SC flap technique (ctd.)modified EEA with SC flap

Variations of SC flap technique (ctd)Subclavian Reimplantation

BALLOON DILATION ANGIOPLASTY AND STENTS

BALLOON DILATION ANGIOPLASTY First demonstrated for

neonatal coarctation in 1979 (Lancet, 1979)

Balloon angioplasty versus surgery (Shady et al, Circulation 1993;87:793)

First prospective comparison 36 patients Age ranges 3-10 years All <1 cm coarctation Both procedure produced 86% reduction in

peak systolic gradient. Follow up aortogram in 19 and MRI in 21

Comparison of angioplasty and surgery for

unoperated coarctation of the aorta (Shady et al,

Circulation 1993;87:793)

Complications of balloon angioplasy

Restenosis (residual gradient 20 mm Hg.): 20-35%

Aortic dissection or rupture Aneurysm formation Femoral arterial complication:15%

Indications for balloon angioplasty

Major systemic illness that significantly increase the risk of surgical intervention

Older patients with mild discrete coarctation of the aorta and poorly developed collaterals.

Balloon dilatation for recurrent (post-op) coarctation In contrast to ‘NATIVE’ coarctation, fibrous

postsurgical perivascular scar allows safe use of this technique in ‘RECURRENT’ Coarct

The previous method of surgical repair did not affect the results.

Considered as a “PROCEDURE OF CHOICE FOR RECURRENT COARCTATION OF THE AORTA AFTER SURGICAL REPAIR”

STENTING

O’Laughlin et al in 1991 reported the first use of endovascular stent.

Recurrent coarctation of the aorta and also as a primary therapy for native coarctation.

Stenting (ctd.)

Implantation of stent after angioplasty limits the risk associated with angioplasty and minimal residual gradient.

Improved luminal diameter Sustained hemodynamic affects Stents subsequently dilated as the child

grows

POTENTIAL COMPLIATIONS OF SURGERY

POTENTIAL COMPLIATIONS OF SURGERY Recoarctation Paradoxical hypertension Paraplegia Recurrent laryngeal nerve injury Left arm ischemia Hemorrhage Aneurysm formation Chylothorax Horner’s syndrome Phrenic nerve injury stroke

PARADOXIC POSTOPERATIVE HYPERTENSION “THAT THE CORRECTION OF A

COARCTATION OF THE AORTA, AN APPARENTLY STRAIGHTFORWARD CAUSE OF HYPERTENSION, CAN PROVOKE A POSTOPERATIVE INCREASE IN BLOOD PRESSURE IS UNEXPECTED AND ILLOGICAL, HENCE THE NAME”

Pathology of persistent hypertension

Increased aortic wall stiffness-Generalized vascular abnormality-Upstream vascular abnormality-Altered baroreceptor function Persistent humoral hyper-responsiveness Residual elevation of LV mass-Myocardial hypertrophy-LV hyperkinesis-Endocardial fibro-elastosis

Pathology of persistent hypertension(2 hypertensive responses) FIRST response occurs immediately Due to release of the stretch on the

baroreceptors in the carotid arteries and aortic arch after removal of the obstruction

Remains until the baroreceptors are set at a lower level

Occurs in 50% of patients In most cases subsides within 24 hours

Pathology of persistent hypertension(2 hypertensive responses) ctd. SECOND phase is more pronounced in

diastole appears within 48 to 72 hours Occurs in about 1 / 3 of those experiencing

the first phase Raised renin and angiotensin Adaptation gone awry that ensures adequate

flow to exercising muscles below the coarctation, above and beyond that delivered by increasing the systolic pressure.

Hypertension (ctd)

IV NTG, SNP, Esmolol, eventual conversion to oral propranolol and captopril

Hypertension usually resolves within 2 to 4 weeks after surgical correction

Tendency for the hypertension to persist late after repair is proportional to the age of the child

Late hypertension (results)

Seirafi and colleagues reported only 2 of 48 infants had late hypertension versus 16 of 59 patients operated on after 1 year of age (ATS 1998)

The incidence of a normal BP was 90% at 5 years and fell to 50% and 25% at 20 and 25 years (Toro-Salazar, Am J Cardiol 2002)

Normotensive patients any age often have an exaggerated rise in systolic pressure in response to exercise (Simsolo, Am Heart J 1998)

Late hypertension (ctd)

Persistent hypertension after repair of coarctation of the aorta despite medical intervention merits investigation to rule out a recurrent coarctation

COMPLIATIONS OF SURGERY(ctd) MESENTRIC ARTERITIS Due to sudden increase in the arterial

pressure in these arterioles which were previously accustomed to a very low blood pressure

Abdominal pain, distension, tenderness and GI bleed on occasions

NPO for first 48 hours after coarctation repair for the fear of this complication

PARAPLEGIA

First reported by Gross and Hufnagel as a complication in animals (N Engl J Med 1945)

Lerberg reported an incidence of paraplegia of 1.5% (5/334) and correlated with the length of aortic cross-clamping (ATS 1982)

Crawford (JTCVS 1982) had intraoperative hyperthermia associated with spinal cord complications

Prevention of spinal cord ischemia

Limit cross clamp time to less than 30 minutes.

Do not sacrifice Intercostal arteries. Avoid clamping left subclavian artery. If

mandatory, try with partial clamp Systemic hypothermia (cooling blanket) to

34oC-35oC Topical cooling: wash left pleural cavity with

ice-cold saline.

Prevention of spinal cord and renal ischemia (ctd.)

Keep proximal aortic pressure to 100 to 120 mm Hg for infants, 160-200 mm Hg for older children

Drugs: methyl prednisolone (25 mg/kg). Mannitol (1 gm/kg)

Intrathecal papaverine. Avoid SNP during clamp

Prevention of spinal cord and renal ischemia (ctd.) Monitor distal perfusion pressure after

proximal clamp. If < 50 mm Hg, supportive measure to improve distal perfusion are required:

- Intra-aortic shunt.

- Extra-aortic shunt. (Gott’s)

- Fem-Fem bypass

Preoperative identification of patients with poorly developed collaterals. Absence of rib notching or palpable para

scapular pulsations in older patients. Unilateral rib notching. Only mildly diminished femoral pulses ( coarctation is not server enough and hence

collateral development will be poor) Decreased Lt or Rt radial pulse

ANEURYSM FORMATION

Both True and False aneurysms occur after all types of repair for coarctation of the aorta.

Also occur in patients with Coarctation not undergoing surgical repair (The risk of aneurysm formation in untreated, native coarctation has been estimated to be 20% by the end of the third decade of life)

Aneurysm formationRisk factors Dacron patch Excision of coarctation ridge Age > 16 years Arch hypoplasia Repeat surgery

Aneurysm formation (ctd)DACRON PATCH The incidence of aneurysm formation

appears to be significantly higher after Dacron patch as compared to PTFE

Aneurysm formation after prosthetic patch aortoplasty Posterior aortic wall opposite the patch

- Different tensile strength of the patch and the posterior aortic wall, the pulsatile waveform being completely directed to the posterior aortic wall

Posterior coarctation membrane ( fibrous shelf) - In initial descriptions of

this procedure , the shelf was excised, however, it causes disruption of intima and predisposes to aortic aneurysm formation

- excision is no longer recommended

Aneurysm formation (ctd)Transverse arch hypoplasia Thomas et al (Ann Thorac Surg 2003;76:1090-1093)

between 1970 and 1995 , 38 patients Aortic arch hypoplasia associated with

coarctation independently predicts future aneurysm formation.

Aneurysm (management)

Historically, this complication has been managed surgically but, endoluminal repair via exclusion of these aneurysms has recently been established as an, less invasive management option

HEMORRHAGE

Even though none of the technique used requires intravenous heparin (except if CPB is used), moderate amount of bleed is present until clots form within the needle holes

CHYLOTHORAX

Caused by traumatic lacerations of lymphatics and thoracic duct

Different therapeutic approaches:

- purely conservative (elemental diet or TPN)

- surgical (early or late)

- ligation of thoracic duct

- pleurodesis

- pleuroperitoneal shunts

Recoarctation and complex coarctation

RECOARCTATION

Recoarctation or residual coarctation is defined as:

“ A postoperative arm-to-leg peak systolic pressure gradient exceeding 20mm Hg across the repaired area”

Recoarctation (ctd)

Age < 3 months Weight < 5 Kg Morphology of Coarct Suture material Technique Residual ductal tissue

Recoarctation (ctd)TECHNIQUE PATCH AORTOPLASTY is excellent for older

children but probably should not be used in infants because of the high recoarctation rate

EXTENDED RESECTION WITH END TO END ANASTOMOSIS appears to have the lowest recoarctation rate

(Mavroudis and Backer, 3rd edition)

Recoarctation (ctd)

SUTURE MATERIAL AND RESIDUAL DUCTAL TISSUE:

High incidence of recoarctation in initial reports due to use of silk sutures, Inadequate resection of ductal tissue, circumferential suture line

Recoarctation diagnosis

Doppler, MRI, DSA Most effective approach is “ Physical

examination + MRI” Pressure measurement after the exercise

(not resting gradient)

Recoarctation Management

-Balloon angioplasty is now considered the initial procedure of choice

-25% of patients have short lived improvement

-Repeated procedures can be safely performed

-Stenting- lower recurrence and aneurysm formation

-Surgery if balloon angioplasty unsuccessful or not indicated

REOPERATION

Difficult due to scarring and increased risk of paraplegia ( since gradient is not high so the collaterals are not well formed)

Left heart bypass or hypothermic circulatory arrest should be seriously considered

Patch angioplasty, resection and interposition graft, extra-anatomic bypass graft technique

Complex coarctation of aorta

Defined as a “ long coarctation or recoarctation segment, a pseudoaneurysm at a previous aortic isthmus suture line, or concomitant hypoplasia of the aortic arch”

Extra-Anatomic Aortic Bypass Grafting

Indications: coarctation or recoarctation and associated

cardiac problems that required repair through median sternotomy

complex coarctation or recoarctation, with anticipated difficulties with direct anatomic repair

Extra-Anatomic Aortic Bypass Grafting (ctd) Ventral aorta repair midline sternotomy, extended

into an upper midline laparotomy

supraceliac abdominal aorta dissected and looped

distal anastomosis to this portion of the aorta performed first

tunneled through a fenestration in the right hemidiaphragm

carried anterior to the inferior vena cava along the lateral border of the right atrium, and anastomosed proximally on the right lateral aspect of the ascending aorta

Extra-Anatomic Aortic Bypass Grafting (ctd) 1980, Vijayanagar et al ( JTCVS 1980)

described exposure of the descending thoracic aorta through a median sternotomy and posterior pericardium, with graft around the left margin of heart

Powell et al (Tex Heart Inst J. 1983 ) described a modification of this technique, which routed the graft around the right margin of the heart

Associated cardiac defects

VSD + CoA

Both volume and pressure overload of LV Treatment options depend on:- Size of VSD and degree of shunt- Type of VSD- Age- Severity of coarctation

VSD + CoA

1. LARGE VSD, SEVERE COARCT IN FIRST MONTHS WITH INTRACTABLE CCF:

Emergency Coarct Repair

CCF persistant

VSD closure

stable

MFU / VSD closure later

Swiss cheese

PA Band

VSD + CoA (ctd.) LARGE VSD, SEVERE CoA, PRESENTS BEYOND FEW

MONTHS OF LIFE

SIMULTENOUS REPIAR

VSD + CoA (ctd.)

SEVERE COARCT SMALL VSD

ONLY CORCT REPAIR

SUBSEQUENT VSD REPAIR RARE

VSD + CoA (ctd.)

LARGE VSD COARCT MODERATE

VSD REPAIR

COARCT REPAIR 6-12 MTHS OF

AGE

Coarctation of the aorta and associated cardiac defects: Congenital Valvular Lesions Bicuspid aortic valve is found in 20%to 85%of

patients. Significant stenosis and/or regurgitation develops in

up to two thirds of cases, of whom at least 10% will require aortic valve replacement

associated with a risk of aortic aneurysm and dissection

Bicuspid aortic valve is responsible for many of the cases of cardiac failure, which accounts for up to 20% of late deaths

2-stage repair through median sternotomy and lateral

thoracotomy (Ann Thorac Surg 1997;64:1309-1311)

correcting the valvular lesion before the coarctation

reduced forward flow through the coronary arteries during the diastolic phase in the setting of aortic incompetence

myocardial blood flow is further substantially reduced by the acute decrease in systemic vascular resistance if the coarctation is repaired first

one-stage approach

1-stage simultaneous correction of both lesions through a median sternotomy (Circulation. 2001;104:I-133.)

number of surgical procedures and length of hospital stay reduced

Pregnancy after coarctation repair

Increased incidence of aneurysm formation and rupture

ACE inhibitors avoided (fetal skull abnormalities and renal tubular dysgenesis).

Beta blockers preferred for control of hypertension

Pregnancy postponed till aortic dilation/aneurysm ruled out

Natural history vs. surgical results

Natural history

first and largest post-mortem series was published by Abbott in 1928, who collected findings from all 200 previously documented cases over the age of 2 years, dating from the first report of aortic coarctation by Paris in 1791.

Reifenstein, Levine and Goss subsequently reported 104 further cases from the literature dating from 1928 to 1947. The median age of death for all 304 cases was 31 years, and 76% of deaths were attributed to complications of the aortic coarctation.

Results of the repair of isolated coarctation (Kirklin) SURVIVAL:

Early deaths

-Neonates 2-10%

-Older infants and children 1%

Among a heterogeneous groups of patients undergoing repair of isolated coarctation, the one-month and 1, 10 and 25 years survival has been 98%, 97%, 91% and 81% respectively

Incremental risk factors for late death

Late age at operation Associated cardiac anomalies Persistent or recurrent hypertension Persistent or recurrent coarctation Aneurysm formation Coronary artery disease

Decision making

TIMING of elective repair

Debatable. Certain considerations are:

1. Higher incidence of re-Coarctation (10 – 30%) if operated before 1 year of age.

2. Increased prevalence of residual hypertension with age (6% between 1 to 5 years vs. 30-50% if operated at later age.)

3. Increased complications (rupture, dissection, aneurysm) with age

TIMING of elective repair (ctd.)

1. The normal descending aorta attains about 55% of its final diameter by 3 years of age (Significant obstruction occurs only if the aortic diameter is reduced by 50%)

2. Concern for ductal remnants till 3 months of age.

TIMING of elective repair (ctd.)

Current trend at some centers :

Operate at any time after the age of 3 months

General consensus:

Operate asymptomatic patients at about 1 year of age or at the time of diagnosis is made later after 1 year of age.

Decision making

Coarctation should be repaired at the earliest to minimize the incidence of late hypertension

Resection/extended resection and end to end anastomosis / subclavian flap for neonates

Patch aortoplasty with PTFE for children > 2 years of age

For children with 2-16 year age group, interposition graft placement

Balloon dilation is the initial procedure of choice for recoarctation, if unsuccessful, patch aortoplasty or interposition graft

Complex coarctation of the aorta single stage repair

THANK YOU