Thread by @PedsIntensiva

1st ever regular episode of Pediatrica Intensiva, the podcast that bridges the gap btw literature & practice for #pedsICU

Borderline Left Hearts w @laussen_peter from @BostonChildrens @SickKidsNews, part 1 of Single Ventricle season

Tweetorial👇

apple.co/36FG2EN

Borderline Left Hearts are subset of pts w critical L heart obstruction, best defined as:
1.‘Output of aortic valve inadequate to maintain life’ (so need to maintain duct until 1st intervention) &;
2.Present & need intervention in neonatal period

#PedsICU #PedsCICU #CHD /2

Infants w critical left heart obstruction are on spectrum
-One end: clearly inadequate L heart structures -> single V pathway
-Other end, clearly adequate (even if bit small) -> biV pathway
- Pts in middle are TRICKY (hence this podcast)

#PedsICU #PedsCICU #CHD #pedscards /3

Terminology re borderline L heart is messy & only partly bc pts complex

Same pt could be: critical AS or LVOTO, borderline LV, HLH, HLHS, hypoplastic LH complex, hypoplast, Shone or Shone-like complex, smallish LV, serial LH obstruction or hypoplasia, etc

#PedsICU #CHD /4

Cardiac MRI v useful to assess borderline L heart & decide whether LV can maintain systemic circulation

Assesses volume of LV & determines % systemic flow from LV vs RV/PDA?

Neonates feed & sleep only, no need for anesthetic

#whyMRI #PedsICU #PedsCICU #CHD #pedscards /5

A critical question for borderline L heart pts is “can we get the left side to grow?’

The Achilles heel for these pts is often the LV inflow (the mitral valve)

#whyMRI #PedsICU #PedsCICU #CHD #pedscards /6

In past, borderline L heart pts on biV pathway often left w mitral stenosis

Over time -> LA hypertension -> inexorable pulm HT -> unable to rescue

Better assessment & decision making has lead to fewer of these patients

#PedsICU #PedsCICU #CHD #pedscards /7

1990s (back in the day...) new approaches to encourage LV growth in borderline L heart

Fixed LVOTO & MS & resected EFE to encourage flow into LV + Restrictive atrial septum enabling L to R shunt at ASD

These early pts were terribly sick

#PedsICU #PedsCICU #CHD #pedscards /8

Later approaches to borderline L hearts:
- staged procedures to avoid excessive neonatal insult
- strategies to encourage L heart growth
- delayed decision /commitment to 1 or 2 V pathway depending on pt response (avoid 'burning bridges')

#PedsICU #PedsCICU #CHD #pedscards /9

Some borderline LH pts get BiV strategy from start (albeit usually w ASD)

Some have neonatal Stage 1 (Norwood) type procedure (w partly restrictive ASD) & later go back to BiV

#PedsICU #PedsCICU #CHD #pedscards /10

Borderline LH pts can have neonatal Norwood-like procedure w LVOTO & arch repair & DKS & later go to BiV
Key points:
1.Atrial septum restricted to encourage LV inflow & growth (c.f. Norwood)
2.Ultimate biV if LV grows (+DKS take down)

++ complex decisions

#pedsICU #CHD /11

Borderline L heart v sick post BiV surg w LCOS & restrictive LV

Maintain LV fill w LAP ~mid teens (+LA line), don't afterload reduce

‘Tanked & tight’ (legend has it @laussen_peter once had t-shirts made!)

Sedate, paralyse, keep cool (35-36 deg)

#pedsICU #pedsCICU #CHD /12

Resecting endocardial fibroelastosis in borderline L heart (‘L heart rehab’) has benefit but can cause ++damage & needs to be done carefully / staged

EFE also invaginates into muscle & reflects longstanding global myocardial pathology

#pedsICU #pedsCICU #CHD #pedscards /13

Borderline L heart has serial L heart obstruction w most/all L side involved – institutional approach needed to get every element & intervention right from fetus to adult

Complex biV repairs w substantial mortality & morbidity

#pedsICU #pedsCICU #CHD #pedscards #ACHD /14

We can measure LV or mitral valve in borderline L heart but these structures are in growing patients & also have potential to grow

Predicting which ones will grow (safely) requires institutional approach & experience

#pedsICU #pedsCICU #CHD #pedscards /15

Mitral valve most important consideration in borderline L heart?

AV, arch, etc. we can fix. But MV is v hard to fix & getting it wrong means pulm HT

Surgical MV repairs have improved & now have option of Melody Valve in mitral position

#pedsICU #pedsCICU #CHD #pedscards /16

Melody Valve in mitral position =surgically implant Melody (us. transcatheter) in mitral pos in small pts w MV disease who prev. had few options

Ultimately requires replacement but allows growth for up to a year & can even be cath balloon dilated

#pedsICU #pedsCICU #CHD/17

Complex BiV get better slowly, ‘stuck or slow?’ hard. Can take >1wk

Good early signs: HR reducing (<150 good, <140 better), RV pressure not rising or suprasystemic on echo, weaning paralysis. LAP can stay hi for ages
Later: able wean vent & sedation
#pedsICU #pedsCICU #CHD /18

For struggling borderline L heart pts – mostly need to wait. 72 hrs consider investigation & decide if intervention warranted (but most of the time just need to wait...)

Consider open chest, ECMO

Requires patience, institution approach & experience!

#pedsICU #pedsCICU #CHD /19

Previously all borderline L heart pts came back from BiV ops w open chests

With experience, finding some pts some can come back closed & data shows prob better for pts

Re-opening is always an option if 'thoughts & prayers' not working....

#pedsICU #pedsCICU #CHD /20

Some borderline L heart pts develop PHT from LA hypertension & are untransplantable

In these pts LVAD can bridge to transplant candidacy by decompressing LA & allowing PHT to resolve

#pedsICU #pedsCICU #CHD /21

Persistence w failing biV strategy in borderline L heart can deny pts option of both Fontan AND heart tx = no options left

Sometimes we need to abandon next procedure we ‘could just try’ & change direction

Decision making process & quality is key

#pedsICU #pedsCICU #CHD /22

3 things that can improve mx of #CHD patients:

-Single V / complex BiV team or program
-Team huddle on EVERY pt (incl. ad hoc for emerg)
-Routine review of EVERY case (not just bad outcomes), @SickKidsCCM calls these ‘performance rounds’

#pedsICU #pedsCICU #pedscards /23

It's impossible to standardise ‘recipe’ for managing complex patients as need individualised treatment for physiology

But we can, and should, standardise our thinking & decision making structures about patients to make better decisions

#pedsICU #pedsCICU #pedscards #CHD /24

Link to podcast here apple.co/36FG2EN

Tweetorial will continue!

Must be vigilant about residual lesions & surgical options in borderline L heart but know that:
-Surgery is always injurious
-Not all problems fixable w re-do
-Pulm vasculature may not remodel, even if downstream LH obstruction improved

#pedsICU #pedsCICU #CHD #pedscards /25

Hybrid approach option in borderline L heart:
-Stent PDA, bilat PA bands
-Aim atrial septum slight restrictive

Buys time until decision re. BiV vs single V depending on response, growth, etc

Problematic if only do for hi risk pts

#pedsICU #pedsCICU #CHD #pedscards /26

Milrinone in the bin!* Treated like holy water but also has downsides. Long half life, vasodilation, not tolerated in some pts (e.g borderline L heart)

Reduce dose /stop if able to allow SVR⬆️ Evidence for ‘lusitropy’ lacking

*1/2 joking
#pedsICU #pedsCICU #CHD #PedsCards /27

Borderline L heart (LA hypertension) analgesia & sedation. Aim smooth. Dexmed / clonidine + morphine. No benzos preferred.

Dexmed expense++, clonidine cheap

Aware bradycardia / hypot. Later withdrawal / weaning can keep pts in #PedsICU

#pedsICU #pedsCICU #CHD #PedsCards /28

Problem w sedation protocols is most are v good at escalation but not reduction

Also, most scores have movement component…& sedatives are bad at stopping movement -> endless escalation

We create problems down the track for us & our pts

#pedsICU #pedsCICU #CHD #PedsCards /29

Treating cardiac sympathetic responses w sedation is problematic – can do it but requires giant doses

Avoiding this requires institutional & individual experience & comfort to say ‘this baby is going to take a while & we should just wait’

#pedsICU #pedsCICU #CHD #PedsCards /30

Borderline L heart pts timeframe to improve longer than most #CHD pts who have ~12 hr timeframes to improve

Look at global picture over 3 day timeframe, not just 🔼LAP. Is vent / sedation down a little? Tolerating feeding?

Attention to detail

#pedsICU #pedsCICU #PedsCards /31

Borderline L heart pts have diastolic LV failure > systolic

They like being 'tanked & tight', don’t like vasodilation

Low dose norepi helpful, +/- low dose epi. If need fluid, give v slowly (1ml/kg at a time) aim for LAP low-mid teens

#pedsICU #pedsCICU #PedsCards #CHD /32

A good single ventricle is better than a bad 2 ventricle

Aggressive pursuit of BiV in borderline L heart is INSTITUTIONAL choice, not individual pt / dr. Takes whole team

If unfamiliar w restrictive LV physiology, single V pathway safer

#pedsICU #pedsCICU #PedsCards #CHD /33

That's the end of Tweetorial for this episode of @PedsIntensiva

Really hope you found it helpful. Please subscribe on iTunes & tell your friends. Audio here apple.co/36FG2EN

Next week - Residual Lesions w Mike Seed @SickKidsNews
#pedsICU #pedsCICU #PedsCards #CHD

Here's the written summary for those unable to listen

Link to PDF drive.google.com/file/d/1wafOl1…