Pulmonary Hypertension In Pediatrics

Transcription

1 Plmonary Hypertension In Pediatrics This talk will focs on the cases and treatment of the more common things we see in pediatrics. This incldes: Persistent Plmonary Hypertension of the Newborn. Plmonary hypertension in the patient with chronic lng disease (bronchoplmonary dysplasia). Single ventricle hearts. Idiopathic plmonary arterial hypertension.

2 Plmonary Arterial Hypertension One sbclass is plmonary hypertension (PAH) Other sbclasses inclde: Plmonary hypertension associated with left heart disease. Plmonary hypertension associated with lng disease/hypoxemia. Inclded in this category is developmental lng disease. Plmonary hypertension associated with thrombotic or embolic disease Miscellaneos like sarcoidosis, tmor airway compression,

3 Updates to PAH Categories We all know that the prematre infants with BPD are becoming a larger part of or patient poplation. In 2013 an pdate to the classification of PAH was done to inclde developmental conditions. (Simmonea). This sggests to me that the BPD infants are a larger poplation of patients with plmonary artery hypertension.

4 Plmonary Hypertension (PH) Definition: a mean plmonary artery pressre greater than 25 mmhg at rest. A sbset of patients will have plmonary arterial hypertension where: The plmonary capillary wedge pressre is less than 15 mmhg. The plmonary vasclar resistance is greater then 3 wood nits/meter sqared. Ratio of mean plmonary artery pressre to mean systemic pressre is greater then.5

5 PAH srvival In 1991 NIH registry stdy median srvival for ntreated children was 10 months, it was 2.8 years for adlts (D Alonzo). Recent stdy by Ziljstra sggested srvival rates at 1,3,5, and 7 year transplant srvival was 96%, 89%,81%,and 79%.

6 Single Ventricle and PAH In the patient with a single ventricle, after the final palliation, the plmonary blood flow is dependent on the passive flow of blood from the SVC and IVC. The traditional definition of a MAP is too high for these patients. We se a MAP of less then or eqal to 15 mmhg.

7 Plmonary Vasclar Resistance PVR A calclation which represents the stiffness of the plmonary arterial bed. The PVR may be compared to the systemic vasclar resistance. The PVR in wood nits is calclated with mean plmonary artery pressre LA (PCWP) divided by Qp. LA is left atrim pressre, PCWP is plmonary capillary wedge pressre, Qp is plmonary flow.

8 Clinical Assessment OI/ Satration Oxygenation index (OI) is FIO2 x MAP x 100/PAO2 A higher OI is bad. An OI>20 bad, >40 consider ECMO if other therapies did not work. Consider ino with O1>15 Predctal satration 20%> then posdctal satration sggests PAH.

9 Echocardiogram in Plmonary Hypertension Enlarged RV. Flattened IVS. Dcts with bidirectional flow. PFO with right-to-left or bidirectional flow. Tricspid insfficiency with elevated RV-RA velocity (pressre gradient).

10 Left-to-right Dcts

11 Right-to-left shnt at PDA

12 Bidirectional PDA

13 Tricspid Insfficiency

14 Large Right Ventricle

15 Tricspid Insfficiency

16 Assessment of Fnction Stats 6 minte walk test in children greater than age 7 Years. A recent stdy showed that in children who can walk less then 6MWD<352 meters and desatration were associated with a worse transplant free srvival (Dowes). Other stdies have not demonstrated the 6MWD to be a predictor for srvival (Van Loon). For older children cardioplmonary exercise testing can be helpfl.

17 Assessment of Mortality Risk BNP is brain natriretic peptide (BNP). Patients with BNP > 180pg/ml had worse srvival. NT-proBNP is the N-terminal pro-brain natriretic peptide. Patients who have a NT-proBNP >than 1200ng/L had a worse prognosis (Ploegstra et al).

18 Cardiac Catheterization Invasive testing with right heart and left heart catheterization. Measrements inclde: right atrial, right ventriclar, plmonary artery pressres as well as a Plmonary capillary wedge pressre, LV pressre, aortic pressre. Vasoreactivity testing with 100% oxygen and ppm ino. Vasoreactivity testing positive if >20% drop in mean plmonary artery pressre, preservation of cardiac index and improved PVR:SVR ratio.

19 Acte Responders Approximately 6-20% of individals respond to ino and oxygen. Srvival better in pediatric patients who are acte responders (Dowes, JACC 2016). Acte responders may respond to calcim channel blockers. Calcim channel blockers cannot be sed in patients with high right atrial pressre or low cardiac otpt.

20 Oxygen Oxygen is a very potent plmonary vasodilator. However althogh hypoxia increases PVR, hyperoxia does not frther decrease PVR then appropriate oxygen and instead reslts in free radical injry. The reactive oxygen species can inactivate NO, decrease enos and sgc ativity and increase PDE5 activity. This will decrease cgmp and add to increased plmonary artery vasoconstriction.

21 Calcim Channel Blockers (CCBs) CCBs work by relaxing the arteriolar mscles. Doses are higher than wold be sed for systemic hypertension. Examples of CCBs: Nicardipine Amlodipine Diltiazem Nifedipine

22 Pathways to treat PAH cgmp pathway. ino increases cgmp. Sildenafil blocks degradation of cgmp. camp pathway. Prostaglandin I2 (Prostacyclin) and analogs and PGE1 increase prodction of camp. Milrinone blocks degradation of camp. Endothelin pathway has ETA (constricts) and ETB (dilates) receptors. Bosentan works on both.

23 Plmonary Vasodilators cgmp Pathway Sildenafil tadalafil ino riocigat Endothelin Pathway bosentan ambrisentan camp Milrinone Prostaglandin E1 Prostacyclin I2 Prostacyclin analogs: Iloprost, Epoprostenol, Trepostinil, Beraprost

24 Slide in Yor Handot

25 ino This is the only FDA approved specific plmonary vasodilator therapy for infants. Common dose is 20ppm. Higher doses have not been shown to be effective. Up to 40% of infants cold be nonresponders. Yonger prematre infants more likely to be non-responders. Expensive and not available everywhere.

26 When ino Does Not Work Try adding medications. Milrinone is sally easily available and has been shown to be helpfl in ino resistant plmonary hypertension. Intravenos sildenafil also may help. Oral sildenafil has been sed as well. Several stdies sed Iloprost as a second agent.

27 Sildenafil Intravenos Loading dose of.4/mg/kg over 3 hors. Maintenance dose of 1.6 mg/kg/day iv. Dosing above for > 34 weeks gestation and <72 hors old.

28 Sildenafil Enteric Dose is sally 1 mg/kg/dose q6 or q8 hors. Higher doses may reslt in higher mortality. Dosing same whether sed in patients with acte PPHN or BPD associated PAH.

29 Sildenafil Warnings On 08/30/12 FDA recommended against sing Sildenafil in children age 1-17 becase of increased mortality in high dose treatment grops, from a stdy in None of the patients in the treatment grop were neonates. On 03/31/14 FDA revised statement saying that health care professionals shold se their discretion, bt that high dose Sildenafil shold be sed with cation.

30 Sildenafil and Prematre Babies Mltiple stdies have examined sildenafil in prematre infants and have fond improvement in their echocardiographic parameters of PH. However, sildenafil does not help prevent BPD. Mltiple stdies have also examined the effect of sildenafil on patients with BPD and fond at least >20% drop in plmonary artery pressres. Some of these stdies sed other drgs for plmonary hypertension as well with improved sccess with more than one therapy.

31 Bosentan Based on several pediatric randomized demonstrated safety and efficacy of bosentan. As of 9/2017 it was approved for pediatric se. Usage is limited by oral formlation in the acte phase of PAH. Liver toxicity can occr. Dose is 1-2mg/kg/dose BID. Combination therapy with PDE-5 inhibitor and bosentan increases srvival in ipah and BPD.

32 Milrinone Milrinone is a phospodiesterase III inhibitor. By inhibiting PDE3 less camp is broken down. Most stdies sed Milrinone as an adjvant therapy in patients who were ino nonresponders (defined as an oxygenation index >25 despite 6 hors of ino. Dosage is microgram/kg/min. Clinical improvement seen in PA pressres and cardiac otpt.

33 Prostaglandin I2 and E1 and Their Analogs Prostacyclin (PGI2) and Iloprost can be given throgh the endotracheal tbe even in the patient on a high-freqency ventilator. Iloprost, Epoprostenol can be given intravenosly. Reports come from instittions where ino not available. These medications increase camp.

34 Combination Therapy Two stdies have shown in adlts that combination therapy long term have improved srvival. Therapies sed were PDE-5 inhibitor and ET receptor antagonist.

35 CLD and PAH 1 ot of 4 patients with moderate to severe CLD will develop plmonary hypertension (Kim). Mortality in one stdy was 47% percent in that poplation at 2 years. This stdy however, is from 2007 (Khemani). As the srvival in the extreme prematre infants increases this poplation is likely to grow.

36 CLD/BPD Chronic Therapies Spplemental oxygen Diretics Sildenafil Sildenafil has been shown to help in long term nder the age of 2 (Morani).

37 Cost of Plmonary Vasodilators Riocigat: 30 day spply is 9270$ Bosentan: 30 day spply is 2,970$. Treprostinil :30 day spply is 6,102.24$ Sildenafil: 30 day spply is approximately 55$

38 Conclsion Plmonary hypertension is a relatively common finding in the patients I treat. Many patients with a left to right shnt will have plmonary artery hypertension becase of the excess plmonary blood flow, bt most of them will improve after the shnt is removed. For the patients with PPHN oxygen, ino are the mainstays of treatment with some patients ( non responders) improving with Intravenos sildenafil.

39 Conclsion Approximately cases per million per year of children are diagnosed with IPAH. Prognosis of patients with IPAH has improved bt is still sboptimal. Patients who do not respond to medical therapy may be eligible for a lng transplant, atrial septostomy or Potts shnt (side by side anastomosis aorta to plmonary arter). Median srvival is 4.9 years after transplantation. Acte death is de to rejection, technical aspects. The late deaths are from bronchiolitis obliterans and infection.