Prostacyclin Treatment for Persistent Pulmonary Hypertension of the Newborn

To study the effect of prostacyclin treatment on pulmonary arterial pressure (PAP), systolic pressure (BP), and systemic oxygenation, eight infants with persistent pulmonary hypertension of the newborn (PPHN) born between 34 and 42 weeks' gestation and having a birth weight of 2540–4130 g were studied using Doppler echocardiography. At a mean age of 19 hours (range 3–32 hours), despite maximal ventilator therapy and an FiO₂ of 1.0, the mean PaO₂/PAO₂ was 0.07 (range 0.04–0.09) and the AaDO₂ was 616 mmHg (range 521–654 mmHg). After volume correction and during inotropic medication with dopamine and dobutamine, the mean PAP by echocardiography was 68.6 ± 6.5 mmHg and the mean BP 59.8 ± 4.8 mmHg. Prostacyclin infusion was then started at a dose of 20 ng/kg/min and increased stepwise to a mean dose of 60 ng/kg/min (range 30–120 ng/kg/min) over 4–12 hours, at which time PAP decreased to 49.2 ± 3.5 mmHg (p= 0.0005) and BP to 53.2 ± 9.1 mmHg (p= 0.17); the PAP thereafter remained below the BP. After 72 hours of prostacyclin infusion, PAP was 49.6 ± 18 mmHg, BP 66.1 ± 5.4 mmHg, PaO₂/PAO₂ 0.14 ± 0.12, and AaDO₂ 428 ± 189 mmHg at FiO₂ 0.65. The median duration of prostacyclin infusion was 3.6 days and of respirator treatment 7.0 days. All patients survived without extracorporeal membrane oxygenation. At 6–12 months, none of the patients had severe central nervous system complications, but two had bronchopulmonary dysplasia. These findings indicate that prostacyclin is able to reverse the right-to-left shunt in PPHN by decreasing PAP, and that systemic hypotension can be prevented with adequate volume correction and inotropic medication.     

Doppler Echocardiographic Study of the Pulmonary Artery and Its Branches in 114 Normal Neonates

It has been shown that there are pressure gradients between the main pulmonary artery (MPA) and its two branches in infants undergoing catheterization. This study investigated the blood flow velocities and pressure gradients in the right and left pulmonary arteries (RPA and LPA, respectively) in normal neonates. The MPA and its two branches were examined echocardigraphically in 114 term consecutive healthy neonates aged 1–6 days. The pressure gradients between the MPA and RPA or LPA were calculated. Thirty neonates with pressure gradients above 2.5 mmHg were followed by 3–6 months. The peak velocities in the RPA and LPA (1.16 ± 0.19 and 1.01 ± 0.18 m/s) were significantly higher than that in the MPA (0.84 ± 13 m/s) (both p < 0.001), with that in the RPA slightly higher than in the LPA (p < 0.001). There was an estimated pressure gradient of 2.5–8.3 mmHg between the MPA and RPA in 43% and of 2.5–6.6 mmHg between the MPA and LPA in 16.7% of all neonates. The gradients disappeared within 3–6 months in 12 (40%) of the 30 neonates with an initial gradient above 2.5 mmHg. The differences in blood flow velocities or pressure gradients in the RPA or LPA were probably attributable to the variations in pulmonary arterial pressure, cardiac output, age, and birth weight and can be considered physiologically characteristic in neonates.     

Disease-related response to inhaled nitric oxide in newborns with severe hypoxaemic respiratory failure

Inhaled nitric oxide (iNO) has been shown to improve oxygenation in severe persistent pulmonary hypertension of the newborn (PPHN). However, PPHN is often associated with various lung diseases. Thus, response to iNO may depend upon the aetiology of neonatal acute respiratory failure. A total of 150 (29 preterm and 121 term) newborns with PPHN were prospectively enrolled on the basis of oxygenation index (OI) higher than 30 and 40, respectively. NO dosage was stepwise increased (10–80 ppm) during conventional mechanical or high-frequency oscillatory ventilation while monitoring the oxygenation. Effective dosages ranged from 5 to 20 ppm in the responders, whereas iNO levels were unsuccessfully increased up to 80 ppm in the nonresponders. Within 30 min of iNO therapy, OI was significantly reduced in either preterm neonates (51 ± 21 vs 23 ± 17, P < .0001) or term infants with idiopathic or acute respiratory distress syndrome (45 ± 20 vs 20 ± 17, P < .0001), `idiopathic' PPHN (39 ± 14 vs 14 ± 9, P < .0001), and sepsis (55 ± 25 vs 26 ± 20, P < .0001) provided there was no associated refractory shock. Improvement in oxygenation was less significant and sustained (OI = 41 ± 16 vs 28 ± 18, P < .001) in term neonates with meconium aspiration syndrome and much less (OI = 58 ± 25 vs 46 ± 32, P < .01) in those with congenital diaphragmatic hernia. Only 21 of the 129 term newborns (16%) required extracorporeal membrane oxygenation (57% survival). Survival was significantly associated with the magnitude in the reduction in OI at 30 min of iNO therapy, a gestational age ≥34 weeks, and associated diagnosis other than congenital diaphragmatic hernia. Conclusion, iNO improves the oxygenation in most newborns with severe hypoxaemic respiratory failure including preterm neonates. However, response to iNO is disease-specific. Furthermore, iNO when combined with adequate alveolar recruitment and limited barotrauma using exogenous surfactant and HFOV may obviate the need for extracorporeal membrane oxygenation in many term infants. Received: 24 April 1997 / Accepted in revised form 3 January 1998     

Acute inhibition of Rho-kinase attenuates pulmonary hypertension in patients with congenital heart disease

This study aimed to determine whether the Rho-kinase–mediated pathway is involved in the pathogenesis of left-to-right shunt–induced pulmonary hypertension and whether fasudil exhibits acute beneficial effects on the hemodynamics of these patients. A total of 12 patients with a mean age of 12.3 years were enrolled in a self-controlled prospective study. All the patients had a diagnosis of congenital heart disease with slight to moderate pulmonary hypertension and were scheduled for transcatheter closure. After placement of the catheters, 30 mg/kg fasudil was injected intravenously over 30 min under room air conditions. Hemodynamic parameters including pulmonary artery systolic pressure (PASP), pulmonary vascular resistance (PVR), systemic artery pressure (SAP), systemic vascular resistance (SVR), cardiac input, and blood oxygen saturation were measured and calculated at baseline and 30 min after fasudil injection. After fasudil treatment, PASP decreased to a level 33.03 ± 6.64% less than baseline value (p < 0.01), and maximal PVR decreased to a level 33.03 ± 6.64% less than baseline value (p < 0.01). Cardiac input increased to a level 7.7 ± 5.2% more than baseline value (p < 0.05), and mixed venous oxygen saturation significantly increased to a level 7.7 ± 5.2% more than baseline value (p < 0.01). The left-to-right shunt ratio (Q_P/Q_S) also tended to increase (16.2 ± 12.5% of baseline value; p < 0.01). Whereas SAP showed only a slight decrease (−1.6 ± 3.1% of baseline value; p = 0.08), SVR significantly decreased (−10.2 ± 12.2% of baseline value; p < 0.01), and the PVR/SVR ratio tended to decrease (−23.9 ± 15.1% of baseline value). In conclusion, Rho-kinase is involved in the pathogenesis of left-to-right shunt–induced pulmonary hypertension, and fasudil is a novel therapeutic approach.     

Pulmonary hypertension in patients with complete transposition of the great arteries: Midterm results after surgery

Postoperative results of surgical repair of complete transposition of the great arteries (TGA) with pulmonary hypertension (PH) in 19 patients in whom mean pulmonary arterial pressure was >50 mmHg or the pulmonary/systemic arterial pressure ratio was >0.8 were examined. TGA with intact ventricular septum was diagnosed in 10 patients and TGA with ventricular septal defect in 9. At the time of corrective surgery (arterial switch 10, atrial switch 9), patients ranged in age from 7 months to 14 years (mean 2.4 years). Seventeen patients (89%) survived with New York Heart Association functional class I. Seven patients in whom calculated pulmonary vascular resistance was 10–20 U · m² after surgery survived with subsequent regression of PH. Residual PH was diagnosed in 36% of survivors. Two patients in whom pulmonary vascular resistance was 26 and 36 U · m², respectively, died after surgery. In patients with TGA, severe PH was not necessarily fatal and was potentially reversible after successful surgery.     

Delivery room blood pressure percentiles of healthy,singleton, liveborn neonates

Background: Arterial blood pressure (BP) is one of the four vital signs that reflect cardiovascular status in neonates. The present study aimed to obtain BP percentiles among healthy, singleton, liveborn neonates between 34 and 43 weeks of gestation who were less than 1 h old. Methods: BP measurements were taken after birth in supine‐positioned neonates in the delivery room using an oscillometric device. A total of 982 well‐nourished neonates who did not require resuscitation, were not fetally malnourished, were not admitted to the neonatal intensive care unit and were without obvious congenital abnormalities were included in the study. Results: Sex‐ and type‐of‐delivery‐specific 5th and 95th percentiles BP measurements were obtained for gestation. Mean BP values for systolic, diastolic and mean of term neonates were 63.98 ± 12.29 mmHg, 38.34 ± 11.06 mmHg and 49.32 ± 11.33 mmHg, and late preterm neonates were 61.80 ± 12.46 mmHg, 33.17 ± 9.97 mmHg and 46.52 ± 10.8 mmHg, respectively. There were weak but significant correlations between birthweight, birth length and head circumference and systolic, diastolic and mean arterial BP values (r = 0.20, r = 0.15 and r = 0.20, respectively, P < 0.001). Neonates who were delivered vaginally had higher mean BP values for systolic, diastolic and mean than neonates delivered by cesarean section (P < 0.05). Female neonates had higher systolic BP values than male neonates (P < 0.05). Conclusion: Data presented in this study include sex‐ and delivery‐mode‐specific BP percentile curves using an oscillometric method and serve as a valuable reference for physicians in dealing with the management of singleton, liveborn late preterm and term newborns in the delivery room intensive care.     

Simplified Pulmonary Vasodilatory Testing in the Cardiac Catheterization Laboratory with Nasal Cannula Nitric Oxide

In patients with pulmonary hypertension, pulmonary vasodilator testing with inhaled nitric oxide (NO) during cardiac catheterization provides valuable data for defining future care plans. Previously, the use of delivery systems for spontaneously breathing individuals required a tight-fitting seal by face mask and an approved delivery and dilution device. We hypothesized that a simplified delivery system using nasal cannula could be utilized to effectively deliver NO during cardiac catheterization. We developed a simple delivery system to deliver through a nasal cannula a concentration of NO at 50 ppm at the nares along with supplemental oxygen (O₂) via face tent. We prospectively employed this system for 10-minute intervals on 11 patients (age range, 7 months to 41 years) with pulmonary hypertension undergoing scheduled cardiac catheterization. Mean pulmonary artery pressure (PA_p) decreased from 62 mmHg (range, 38–99) at room air testing to 45 mmHg (range, 36–91) with the addition of NO plus O₂ (p = 0.014). Pulmonary vascular resistance (PVR) decreased from 11.6 U · m² (range, 4.5–43.4) to 6.3 U · m² (range, 2.0–34.2) (p = 0.001). A response of 20% or more reduction in PVR was seen in all 11 patients. The initial ratio of pulmonary to systemic vascular resistance (R_p:R_s) was 0.49 (range, 0.25–3.5) and decreased to 0.35 (range 0.1–2.6) (p = 0.002). No adverse side effects were noted. We found this NO delivery system to be a simple and effective method of pulmonary vasodilatory testing that may have wide applicability in the cardiac catheterization laboratory.     

Pulmonary vasodilator strategies in neonates with acute hypoxemic respiratory failure and pulmonary hypertension

The management of acute hypoxemic respiratory failure (AHRF) in newborns continues to be a clinical challenge with elevated risk for significant morbidities and mortality, especially when accompanied with persistent pulmonary hypertension of the newborn (PPHN). PPHN is a syndrome characterized by marked hypoxemia secondary to extrapulmonary right-to-left shunting across the ductus arteriosus and/or foramen ovale with high pulmonary artery pressure and increased pulmonary vascular resistance (PVR). After optimizing respiratory support, cardiac performance and systemic hemodynamics, targeting persistent elevations in PVR with inhaled nitric oxide (iNO) therapy has improved outcomes of neonates with PPHN physiology. Despite aggressive cardiopulmonary management, a significant proportion of patients have an inadequate response to iNO therapy, prompting consideration for additional pulmonary vasodilator therapy. This article reviews the pathophysiology and management of PPHN in term newborns with AHRF while highlighting both animal and human data to inform a physiologic approach to the use of PH-targeted therapies.     

Persistent pulmonary arterial hypertension of the new born

Persistent pulmonary hypertension of the newborn (PPHN) characterised by right to left shunting with intense cyanosis is difficult to manage, and in the best of centres carries a 40–60 percent mortality. We report our one year's experience of managing six neonates with PPHN. There were 5 males and 1 female with mean birth weight of 2.59±0.487 kg and gestation period 39±2.0 wks and 1 minute Apgar score 2.8±2.1. Four to six babies were born by cesarean section and 3–6 babies had aspiration pneumonia. All babies presented within 12 hours of age (mean 5.08±5 hrs) with intense cyanosis and respiratory distress. Diagnosis were confirmed in all by (a) hyperoxia test, (b) simultaneous determination of preductal and postductal paO₂ (c) contrast echocardiography and (d) hyperoxia-hyperventilation test. Babies were managed with hyperventilation using mean ventilatory rates of 100±45 per minute, an inspired oxygen concentration of 100%, peak inspiratory pressures 27±9 cm of H₂O, and expiratory pressures 5±1.6 cms of H₂O, and mean air way pressures of 10.4±2.7 cms H₂O. Alkali therapy was used in 3 of the six babies whereas low dose dopamine was infused in all six babies. Inspite of aggressive ventilatory therapy, only 3 out of 6 babies could be salvaged.     

Percutaneous Transluminal Angioplasty for Stenosis of the Aorta Due to Aortic Arteritis in Children

Percutaneous transluminal balloon angioplasty for stenosis of the aorta due to aortic arteritis was attempted on 45 lesions in 41 children (age range, 4–14 years; mean, 9.9±4.2 years) presenting with symptoms of hypertension, severe congestive heart failure, and lower limb claudication. Balloon dilatation was technically successful in 38 (92.7%) patients for 41 stenotic lesions (91.1%). The mean peak systolic pressure gradient (PSG) decreased from 71.7 ± 23.9 mmHg to 23.2 ± 17.5 mmHg (p < 0.001) and the diameter of the stenosed segment increased from 3.3 ± 1.1 mm to 7.5 ± 2.2 mm (p < 0.001) immediately after angioplasty. Patients with short-segment (<3 cm) stenosis had a lower residual gradient (17.9 ± 11.1 mmHg vs 30.5 ± 22.6 mmHg; p < 0.05) and a wider diameter of the aorta (8.8 ± 1.1 mm vs 7.5 ± 2.2 mm; p < 0.02) compared to patients with long-segment (≥3 cm) stenosis. Four patients required stent implantation; 2 for flow-limiting dissection, 1 for failure to reduce PSG by >50%, and 1 for recurrent restenosis. There was marked hemodynamic and angiographic improvement in these 4 patients. Hemodynamic and angiographic restudy in 21 of the 41 patients at mean follow-up period of 6.2 ± 4.2 months (range, 3–24 months) showed restenosis in 4 (19%) patients. Restenosis was more common in patients with long-segment stenosis than those with short-segment stenosis (30% vs 9.1%). Late restudy in 8 patients, done at 3–7 years after first restudy, showed no recurrence of aortic narrowing. On clinical follow-up of 38 patients for a mean of 58.8 ± 36.0 months (range, 8–146 months) there was marked improvement in symptoms. Hypertension was cured in 11 (29%), improved in 24 (63%), and persisted in 3 (8%). Six patients with associated severe renal artery stenosis showed further improvement in hypertension after successful renal angioplasty. Severe congestive heart failure improved in 21 (95.4%) of 22 patients. Mean left ventricular ejection fraction improved from 0.32 ± 0.08 to 0.48 ± 0.10 (p < 0.001) at a mean follow-up of 28.7 ± 8.4 months in these patients. Hemodynamic restudy in 10 of these patients showed improvements in left ventricular end-diastolic pressure from a mean 37 ± 9 mmHg (range, 25–55 mmHg) to 16.4 ± 6.2 mmHg (range, 6–25 mmHg) (p < 0.001). Lower limb claudication improved in all 4 patients. Our results suggest that percutaneous transluminal balloon angioplasty in children is safe and highly effective in relieving stenosis of the aorta due to aortic arteritis, with marked clinical improvement, and should be the treatment of choice particularly for discrete stenosis.     

Mean Pulmonary Artery Pressure Estimated from Systolic and Diastolic Pulmonary Artery Pressure in Children with Congenital Heart Disease: An Invasive Study

This hemodynamic study documented the accuracy and precision of six empirical formulas relating mean (mPAP), systolic (sPAP), and diastolic (dPAP) pulmonary artery pressures in children with congenital heart disease. Fluid-filled PAPs of 61 children (age, 26 ± 40 months) were analyzed over an mPAP range of 7 to 74 mmHg. All formulas were accurate (mean bias, −2 to 1 mmHg). The three formulas relying on sPAP and dPAP were dPAP + 1/3 (sPAP – dPAP), dPAP + 0.41 (sPAP – dPAP), and sqrt of (sPAP × dPAP). They were precise (bias standard deviation [SD], 3 mmHg), with approximately 90% of patients exhibiting biases of less than 5 mmHg. The three formulas relying on sPAP alone all assumed that mPAP approached two-thirds of sPAP according to slightly different mathematical equations. They were less precise (bias SD, 5–6 mmHg), with biases greater than 7 mmHg for 10% to 16% patients. Accurate estimates of mPAP were obtained from sPAP alone, and this could be valuable for cross-checking the self-consistency of the pressure database obtained in the echo-Doppler laboratory. For cases that had reliable dPAP estimates available, empirical formulas relying on both sPAP and dPAP were more precise and thus must be preferred.     

Nesiritide Improves Hemodynamics in Children with Dilated Cardiomyopathy: A Pilot Study

Background This study aimed to obtain hemodynamic measurements of nesiritide in children with dilated cardiomyopathy. Methods A prospective, randomized, double-blinded, placebo-controlled pilot study was conducted in the pediatric intensive care unit at the University of California, Los Angeles. All subjects younger than 21 years admitted to the pediatric intensive care unit with a diagnosis of dilated cardiomyopathy and submitted to cardiac catheterization were randomized to receive either nesiritide or placebo. Right heart catheterization with Swan-Ganz catheter placement was performed. Nesiritide was infused over 24 h. Hemodynamic data were obtained before, during, and after the 24-h nesiritide infusion. The measures obtained included pulmonary capillary wedge pressure (PCWP), central venous pressure, mean pulmonary arterial pressure (MPAP), systolic arterial blood pressure (SBP), cardiac index, and systemic vascular resistance. Results The study included 20 children: 9 randomized to nesiritide and 11 to placebo. At 24 h, the mean decreases in PCWP, MPAP, and SBP were significantly greater for nesiritide than for placebo: PCWP (–5.3 vs. 1.2 mmHg; p = 0.02), MPAP (–8.0 vs. 0.4 mmHg; p = 0.006), SBP (–7.9 vs. 2.6 mmHg; p = 0.04). Conclusions Nesiritide significantly decreases PCWP, MPAP, and SBP in children with dilated cardiomyopathy.     

Balloon Angioplasty of Native Coarctation of the Aorta in Infants and Neonates: Is It Worth the Hassle?

Balloon angioplasty (BA) for native coarctation of the aorta (CA) in infants and neonates remains controversial with a high incidence of restenosis. The purpose of this study is to analyze our acute and midterm results for BA of native CA in infants and neonates and try to identify factors that may be predictive of outcome. Between September 1991 and June 1999, 17 patients with CA underwent BA at a median age of 3 months (range 2 weeks–9 months) and median weight of 4.8 kg (range 2.8–7 kg). Fourteen patients had discrete CA and 3 had tubular hypoplasia. All patients were hemodynamically stable prior to BA and no patients had critical coarctation requiring prostaglandin E₁ infusion to maintain ductus arteriosus patency. Seven patients had other associated cardiac defects. All patients had significant initial improvement. The mean peak systolic gradient across the CA improved from 43 ± 15 mmHg to 10 ± 8 mmHg (p < 0.001), and the mean minimum diameter of the aortic lumen increased from 2.4 ± 0.9 mm to 5.2 ± 1.0 mm (p < 0.001). There was no mortality or major complication. At median follow-up interval of 2.7 years (0.15–7.75 years), 10 (59%) of 17 patients are clinically well and have an upper to lower limb systolic blood pressure difference of <20 mmHg. Seven (41%) of 17 patients developed significant restenosis (5 of these patients underwent repeat BA, which was successful in 3 patients). Four (24%) patients underwent surgical repair at a median age of 4.5 months (3–6.9 months) and a median time interval of 4 months (2–6.5 months) from the initial BA. All 3 patients with tubular hypoplasia type of CA underwent surgical repair. No patients developed aortic aneurysm following initial or repeat BA. All patients who underwent surgical repair were 1 month or less in age at the time of their initial BA. We conclude that BA of native CA in infants and neonates can be performed safely with low mortality and morbidity. It appears to offer the best results in patients who are older than 1 month with discrete CA and a well-developed aortic arch. Further restenosis of the discrete CA can be managed successfully by repeat BA.     

Persistent pulmonary hypertension of the newborn with transposition of the great arteries: successful treatment with bosentan

Persistent pulmonary hypertension of the newborn (PPHN) occurs in 1–4% of neonates with transposition of the great arteries with intact ventricular septum (TGA/IVS). This association is often lethal. To our knowledge, only eight survivors have been described in the literature, two of whom benefited from extracorporeal membrane oxygenation (ECMO). We report two cases of PPHN complicating a TGA/IVS that were refractory to multiple therapies and resolved 48 hours after initiation of bosentan therapy. Bosentan, an oral dual endothelin-1 receptor antagonist, is a new treatment for pulmonary arterial hypertension that was both effective and safe in these two cases of TGA/IVS with PPHN. To our knowledge, it is the first use of bosentan in newborns.     

Bosentan for Increased Pulmonary Vascular Resistance in a Patient with Single Ventricle Physiology and a Bidirectional Glenn Shunt

We present a case of the successful use of bosentan for increased pulmonary vascular resistance (PVR) in a 10-year-old male who underwent late single ventricle surgical palliation for double-inlet left ventricle with pulmonary artery banding and a bidirectional Glenn shunt. The patient was treated with bosentan for 16 weeks, with decreases in mean pulmonary artery pressure from 23 to 16 mmHg on the right and from 31 to 21 mmHg on the left, and a decrease of the transpulmonary gradient by 7–8 mmHg. Cardiopulmonary exercise testing demonstrated an increase in peak oxygen consumption (VO₂) by 8% and peak work rate by 10%. Bosentan is a relatively new oral therapy option for increased PVR in patients with single ventricle physiology and bidirectional Glenn shunts.     

Arginine-vasopressin in neonates with vasodilatory shock after cardiopulmonary bypass

Successful therapy of vasodilatory shock in adults and children with arginine-vasopressin (AVP) has been reported previously. Data on the use of vasopressin in neonates is limited. This retrospective study reports the effects of AVP-treatment in neonates with catecholamine-resistant systemic vasodilatation after cardiopulmonary bypass. From March 2003 through December 2005, 172 neonates underwent open-heart surgery, 17 developed vasopressor-resistant hypotension and were treated with AVP. Thirteen patients had a stage I palliation of single ventricle, two had a Ross-operation and two had an arterial switch operation. All patients received multiple traditional inotropes and vasopressors prior to administration of AVP. AVP was started at median 0.0001 U·kg⁻¹·min⁻¹ (range 0.00005−0.0002) and titrated up to a maximum of median 0.0003 U·kg⁻¹·min⁻¹ (range 0.0001–0.001). AVP led to a significant increase in blood pressure (from 49+/−8 mmHg to 69+/− 7 mmHg) and the requirement of traditional vasopressors decreased significantly. Noperipheral vasoconstriction or ischemia was observed. Four of 13 patients, all with single ventricle palliation, died. In two patients death occurred due to additional complications 6 days after AVP was discontinued. One patient, who was still on AVP, died 42 hours postoperatively after prolonged hypoxemia not responding to inhaled nitric oxide. One patient arrested on the third postoperative day when AVP was almost weaned. Conclusion: In neonates with vasodilatory shock after cardiopulmonary bypass AVP is a potent agent to increase blood pressure when traditional vasopressors are failing.     

Relationship of Pulmonary Artery Wedge Pressure to Left Atrial Pressure and Pulmonary Vascular Resistance in Preoperative Fontan Patients

Pulmonary artery wedge pressure (PAWp) as a surrogate for left atrial pressure (LAp) has been validated in patients with fully pulsatile two-ventricle circulations. This study was to validate PAWp as an accurate estimate of LAp for calculating pulmonary vascular resistance in single-ventricle patients after the bidirectional Glenn operation. A prospective study measuring direct branch pulmonary artery pressures, ipsilateral PAWp, and direct LAp to calculate pulmonary and systemic blood flows was conducted. Pulmonary vascular resistance (PVR) was calculated for each patient using the PAWp and compared to the PVR calculated by direct LAp measurements. Twenty-eight patients were enrolled; 27 were eligible for study inclusion. Ages ranged from 21 to 60 months and weights ranged from 9.5 to 20.8 kg. Underlying congenital heart defect diagnoses varied, with all patients either functionally or anatomically univentricular. Left mPAWp measured 4.4 ± 2.6, statistically different from simultaneous direct mLAp of 2.5 ± 2.4 mmHg (P < 0.001. Right mPAWp measured 4.3 ± 3.2 mmHg, statistically different from simultaneous direct mLAp of 2.8 ± 2.6 mmHg (P < 0.001. The PVR calculated using mPAWp was 1.2 ± 0.7 W.U., statistically different to 1.8 ± 0.95 W.U. using mLAp (P < 0.001). The average PVR measurement calculated using mPAWp underestimated the PVR calculated using mLAp by 0.6 W.U. It can be extrapolated that a PVR of 2.3 W.U. calculated using wedge measurements would estimate a PVR of 3 W.U. calculated using direct LA measurements. In this study, the PVR calculated using PAWp as a surrogate for LAp either equaled or underestimated the true PVR, up to 33% different. This difference is important in patients with univentricular physiology who rely on low PVR for cardiac output. Thus, based on this study, a PVR measurement of greater than 2.3 W.U. by the mPAWp method should prompt a direct LA pressure measurement, in order to more appropriately determine true surgical risk.     

Isolated congenital coronary arteriovenous fistula

During the last eight years a total of nine cases of isolated congenital coronary arteriovenous fistula (CAVF) have been diagnosed at our centre. Age of these patients ranged from 11 days to 22 years (mean 6.4±4.2 years). There were seven male and two female patients. Right and left coronary arteries were the sites of origin in seven and three cases respectively. One patient had two fistulae, one each originating from right coronary artery and obtuse marginal artery. The drainage sites were right ventricle in seven cases and right atrium in two. The pulmonary artery pressure was normal in eight cases and elevated in one case. The pulmonary artery to systemic flow ratio ranged from 1.1∶1–2.4∶1 in all except the 11 day-old-baby in whom it was 4∶1. Pulmonary vascular resistance (PVRI) was below 3.5 in all cases (range 1.0–3.5 units). Surgical ligation of fistula was done in four cases and two patients underwent coil embolisation of fistula. Follow-up is available in five out of eight patients including three cases in whom CAVF was closed. Two other young patients are being followed-up conservatively and all the patients are asymptomatic. CAVF can present at any age; majority of the cases have small left to right shunts and more commonly CAVF arise from right coronary artery. Surgical ligation of fistula is safe in older patients, non-surgical embolisation using coils may be an alternative to surgery in selected cases.     

不对称二甲基精氨酸与新生儿持续性肺动脉高压病理进程的相关性研究

目的 探讨不对称二甲基精氨酸(asymmetric dimethylarginine,ADMA)在新生儿持续性肺动脉高压(persistent pulmonary hypertension of the newborn,PPHN)足月儿循环系统中的变化规律及其与治疗响应的关系,探索其成为治疗靶标和治疗响应标志物的可能性...     

Down Syndrome as a Factor Influencing Hemodynamic Response to Pulmonary Artery Banding

The hemodynamic response to pulmonary artery banding (PAB) in relation to the preoperative pulmonary/systemic vascular resistance (R_p/R_s) ratio and to the timing of surgery, with special regard to Down syndrome, was investigated in 56 nonconsecutive pediatric patients aged 3 days to 6 months (mean 2.5 months) with simple and complex congenital shunt-related cardiac malformations. Among the non-Down patient group (39 patients; mean age 6.9 weeks) there was a good hemodynamic response in all but three cases, irrespective of the preoperative R_p/R_s ratio; these three poor responders had preoperatively normal or nearly normal R_p/R_s ratios (R_p/R_s < 0.3) and were affected postoperatively by lung complications. In the Down patient group (17 patients; mean age 8.2 weeks) the mean preoperative as well as the mean postoperative R_p/R_s ratio was higher than in the non-Down patient group (preoperative R_p/R_s 0.49 versus 0.32; postoperative R_p/R_s 0.31 versus 0.18). There was a good hemodynamic response in all five patients with Down syndrome who had preoperative normal or nearly normal pulmonary vascular resistance ratios (R_p/R_s < 0.3). Among 12 patients with Down syndrome and preoperative increased resistance ratios (R_p/R_s > 0.3) PAB did not cause a reduction in pulmonary vascular resistance (PVR) in five patients (postoperative R_p/R_s 0.49–1.00), all operated on at more than 6 weeks of age. PAB resulted in effective reduction of postoperative R_p/R_s ratios (range 0.10–0.27) in seven patients, six of them younger and one older than 6 weeks at the time of the banding procedure. In conclusion, patients with Down syndrome and shunt-related cardiac malformations (predominantly total atrioventricular canal cases) in general have higher pre- and postoperative R_p/R_s ratios than non-Down children and also have a higher potential for developing pulmonary vascular obstructive disease despite hemodynamically effective PAB. Especially in children with Down syndrome and pathologically high resistance ratios, PAB, if indicated, should be performed as early as possible.