PATENT DUCTUS ARTERIOSUS IN NEWBORN INFANTS


PATENT DUCTUS ARTERIOSUS IN NEWBORN INFANTS>DOPPLER CLASSIFICATION OF PATENT DUCTUS ARTERIOSUS
IN ?NEWBORN INFANTS : PREDICTIVITY OF SPONTANEOUS VERSUS TERAPEUTIC CLOSURE

GERBONI S., BRANDIMARTE F., DI VALERIO S.,.QUARTULLI L., SABATINO G.

NEONATAL CARE UNIT UNIVERSITY OF CHIETI ITALY.


SUMMARY
Diastolic ductal steal in newborns with patent ductus ?arteriosus (PDA) ?may generate distrectual ischemia. The AA. propose a Doppler derived classification of five types of fluximetric patterns correlated semiquanitatively to the entity of ductal shunt wich may affect the clinical outcome and management.


INTRODUCTION

Previous Doppler ultrasonographic studies on cerebral, caeliac, descending aorta and renal arteries, showed a decreased and sometimes retrograde diastolic blood flow in newborn infants with PDA. These alterations suggest that cerebral ischaemia, necrotizing enterocolitis or renal failure may be attributed ?to reduced diastolic perfusion of these organs (2,3,4,13,18,21,22).
A global systemic approach has not yet been applied in defining how many fluximetric patterns may be dued to PDA and ?wich ?one, may predict spontaneous versus terapeutic closure or ischaemic complications frequently associated with an important hemodynamic shunt).
The present report studies the blood flow velocity in cerebral, coeliac, mesenteric, renal, femoral and subclavian arteries, of term and preterm infants with echo-Doppler diagnosis of PDA. It aims at finding a semiquantitative classification of PDA and identifying the “hemodynamically significant” left-to-right shunt (6) for medical or surgical management.


MATERIALS
From May 1988 to December 1989 we studied 68 newborn infants with Echo-Doppler diagnosis of PDA during the first 24 h of life (table I). ?40 full term infants (19 males and 21 females, gestational age (GA) 38-40 w.) had a birth weight (BW) ranging between 2950 and 4050 g (mean 3392 g ) and normal findings on physical examination ; all were free of cardiovascular diseases. 28 preterm infants (15 males
and 13 females , EG 28-37 w.) had a birth weight ranging between 950 and 2800 (mean 1970 g ). Four newborns were infants of diabetic mother (IDM), seven had respiratory ??distress sindrom (RDS) and all were free of cardiovascular diseases (NORMAL).


METHODS
The newborn infants were included in this study when the Echo-Doppler diagnosis of PDA
(1,8,10)
were made in the first 24 hr of life. Doppler interrogation of femoral (FEM) and subclavian (SUB) arteries was made by a 5 Mhz stand-alone directional-sensitive Doppler device (Vingmed SD50) in continous or pulsed mode,?in the latter case with a sample volume of axial lenght4 mm and width 6 mm. 2D imaging and Doppler interrogation of ductus arteriosus and PUL, descending aorta (AOR), coeliac (CEL), mesenteric
(MES), renal (REN) and cerebral (CER) arteries were made by a 2D-Color Flow Mapping Sistem (Vingmed CFM 750), with a duplex probe of ?5 or 7.5 MHz for imaging and 4 or 6 ?MHz for Doppler. The sample volume was positioned on 2D sector image. All recordings ?were repeated in the 2nd and 5th days of life. Peak systolic and diastolic velocities ( S and D ) were ?measured ?on Doppler ?sonogram ; pulsatility index ( P.I.) was computed as SD/S. Diastolic reverse flow (DRF) was present ( = ?1 ) when diastolic shift was opposite to systolic shift, or absent ( = 0 ) for no reverse shift. As normal range of P.I. we considered data reported in literature (2,3,4,5,6)


RESULTS
All newborn infants had DRF in PUL at first examination (EXA) made between 6-24 hr (mean 16 Hr). Clinical, fluximetric data and results are included in table I. 13 term infants had DRF in AOR ( 3 at first EXA and 10 at second ), 2 in CEL and REN and 1 in FEM, SUB and CER arteries. The P.I. was in normal range 0.61 +/- 0.10. The ductus closed (CLOS.) spontaneously (SPONT.) in 38 at 2nd EXA, in one by indomethacin
(INDOM.) 0.2 mg/kg e.v three doses e.v. at ?3rd EXA and in another one chirurgically ?(CHIRUR.) after the 3rd EXA. 22 preterm infants had DRF in AOR, 9 in CEL, MES and REN , 6 in FEM and SUB, 4 in CER arteries. The P.I. was above ?the ?normal range ( 0.87 +/- 0.15 ). The ductus closed SPONT. in 19 at 2nd EXA while in 4 closed by INDOM. e.v. and in 4 CHIRUR. respectively at 2nd and after the 3rd EXA


DISCUSSION
Neonatal care, in the past decade, improved so much to led to a marked increase in survival of critical newborn infants ?with associated PDA. An important left-to-right shunting through a PDA was considered as a common cause of serious morbidity. Earlier observations, using echo-Doppler, founded a PDA during the first 12 h of life in the majority of the infants ( from 20 % to 80% of infants without heart diseases
(5,7). This discrepancy as assessed by stand-alone Doppler or 2D imaging and by other methods is obvious. In fact if we examine the infants in the first 6 h of life with a duplex scanner with CW,PW Doppler and a color flow mapping, a PDA is present in 100% of them: this means that the problem is not to diagnose the patency of the ductus but to quantify the shunt necessitating medical o surgical management (1,12,15,17,19,20,21,).
The consensus of National Collaborative Study on Patent Ductus Arteriosus in premature infants for evaluating the role of indomethacin in the management of small premature infants, was to treat infants with a “significant ductus arteriosus” defined on clinical criteria and X-ray cardiomegaly and echocardiographic A/AO ratio > 1.15 (6). Drayton (5) evaluated the ductal flow, subtracting ?flow measured with Doppler above and just below the origin of the ductus and found that a greater ductal flow than 70 ml/kg/min at 48 hours of age predicted the subsequent development of a ductal murmur with a 75% sensitivity and 100% specificity. Doppler quantification of flow has got well defined and known limits (20).In this study we consider the extension of DRF directly
correlated to the entity of ductal shunt and classify it in a very small shunt when DRF is only in PUL or small, moderate, moderate-severe ?and ?
severe if DRF is ?present ?respectively ?in AOR,REN,FEM ?and CER arteries. We name this fluximetric patterns Type I, II, III, IV and V (FIG.1). We consider types IV and V as “hemodynamically significant” shunts.
Types I and II currently and type III frequently close spontaneously during the first 48 h of life ; type III rarely and types IV and V currently necessitate respectively medical or/and surgical treatment.It’s important waiting for 48 hours at least,when pulmonary resistences normalize, for evaluating the real entity of ductal shunt. In this waiting time we use to treat the infants only with a reduced intake of fluid
thereafter, when there aren’t contraindications and the ductus is still patent, we start INDOM. ?0.2 mg/kg e.v. three times every 12 hours. When Indomethacin fails, surgical closure is the rule (8,9,11,14,16,19,20).


CONCLUSION
The Doppler classification that we propose to quantify ductal left-to-right shunt is an objective base for the management of newborn infants with PDA : it is simple, noninvasive and repeatable. Further investigations have to convalidate these our preliminary data.


Correspondence to : S.Gerboni M.D.


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