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In 1998, a clinical classification of pulmonary hypertension (PH) was established, categorizing PH into groups which share similar pathological and hemodynamic characteristics and therapeutic approaches. During the 5th World Symposium held in Nice, France, in 2013, the consensus was reached to maintain the general scheme of previous clinical classifications. However, modifications and updates especially for Group 1 patients (pulmonary arterial hypertension [PAH]) were proposed. The main change was to withdraw persistent pulmonary hypertension of the newborn (PPHN) from Group 1 because this entity carries more differences than similarities with other PAH subgroups. In the current classification, PPHN is now designated number 1. Pulmonary hypertension associated with chronic hemolytic anemia has been moved from Group 1 PAH to Group 5, unclear/multifactorial mechanism. In addition, it was decided to add specific items related to pediatric pulmonary hypertension in order to create a comprehensive, common classification for both adults and children. Therefore, congenital or acquired left-heart inflow/outflow obstructive lesions and congenital cardiomyopathies have been added to Group 2, and segmental pulmonary hypertension has been added to Group 5. Last, there were no changes for Groups 2, 3, and 4., (Copyright © 2013 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.)

Objectives: We investigated the effects of different CO(2) tensions on oxygenation, pulmonary blood flow (Qp), cerebral blood flow, and systemic blood flow (Qs) after the bidirectional superior cavopulmonary anastomosis (BCPA)., Background: Hypoxemia refractory to management of a high pulmonary vascular resistance index (PVRI) may complicate recovery from the BCPA., Methods: After BCPA, CO(2) was added to the inspired gas of mechanically ventilated patients. The Qp, Qs, PVRI, and systemic vascular resistance index (SVRI) were calculated from oxygen consumption, intravascular pressures, and oxygen saturations. Cerebral blood flow was estimated by near infrared spectroscopy and transcranial Doppler., Results: In nine patients (median age 7.1, range 2 to 23 months), arterial oxygen tension increased significantly (p < 0.005) from 36 +/- 6 mm Hg to 44 +/- 6 to 50 +/- 7 mm Hg at arterial carbon dioxide tensions (PaCO(2)) of 35, 45, and 55 mm Hg, respectively and decreased to 40 +/- 8 mm Hg at PaCO(2) 40 mm Hg. At a PaCO(2) of 55 and 45 compared with 35 mm Hg, Qp, cerebral blood flow, and Qs increased significantly, PVRI, Qp/Qs, and the ratio of Qp to inferior vena caval blood flow were unchanged, but SVRI decreased., Conclusions: We have demonstrated that after the BCPA, systemic oxygenation, Qp, Qs, and cerebral blood flow increased and SVRI decreased at CO(2) tensions of 45 and 55 mm Hg compared with 35 mm Hg. We suggest that hypoxemia after the BCPA is ameliorated by a higher PaCO(2) and that low PaCO(2) or alkalosis may be detrimental. Hypercarbic management strategies may allow earlier progression to the BCPA, which may contribute to reducing the interval morbidity in patients with a functional single ventricle.

Objectives: We compared the ability of inhaled nitric oxide (NO), oxygen (O2) and nitric oxide in oxygen (NO+O2) to identify reactive pulmonary vasculature in pulmonary hypertensive patients during acute vasodilator testing at cardiac catheterization., Background: In patients with pulmonary hypertension, decisions regarding suitability for corrective surgery, transplantation and assessment of long-term prognosis are based on results obtained during acute pulmonary vasodilator testing., Methods: In group 1, 46 patients had hemodynamic measurements in room air (RA), 100% O2, return to RA and NO (80 parts per million [ppm] in RA). In group 2, 25 additional patients were studied in RA, 100% O2 and 80 ppm NO in oxygen (NO+O2)., Results: In group 1, O2 decreased pulmonary vascular resistance (PVR) (mean+/-SEM) from 17.2+/-2.1 U.m2 to 11.1+/-1.5 U.m2 (p < 0.05). Nitric oxide caused a comparable decrease from 17.8+/-2.2 U.m2 to 11.7+/-1.7 U.m2 (p < 0.05). In group 2, PVR decreased from 20.1+/-2.6 U.m2 to 14.3+/-1.9 U.m2 in O2 (p < 0.05) and further to 10.5+/-1.7 U.m2 in NO+O2 (p < 0.05). A response of 20% or more reduction in PVR was seen in 22/25 patients with NO+O2 compared with 16/25 in O2 alone (p = 0.01)., Conclusions: Inhaled NO and O2 produced a similar degree of selective pulmonary vasodilation. Our data suggest that combination testing with NO + O2 provides additional pulmonary vasodilation in patients with a reactive pulmonary vascular bed in a selective, safe and expeditious fashion during cardiac catheterization. The combination of NO+O2 identifies patients with significant pulmonary vasoreactivity who might not be recognized if O2 or NO were used separately.

Objectives: We reviewed the factors contributing to or causing death before surgery in neonates with d-transposition of the great arteries (TGA) despite anatomy suitable for the arterial switch operation (ASO) to develop strategies to minimize preoperative attrition., Background: Currently the ASO for neonates with TGA carries a low operative mortality. However, there is a paucity of information regarding the patients who die before the ASO. Strategies to ensure survival to operation are of importance to improve overall outcome., Methods: We reviewed all neonates with TGA and patent forearm ovale (PFO) < or = 2 mm, a birthweight <2 kg, or who died before surgery, between 1988 and 1996., Results: We identified 12 out of 295 neonates with TGA (4.1%) with anatomy suitable for the ASO who died prior to surgery. All had TGA/intact ventricular septum (IVS) and presented with a severely restrictive PFO. In 11 of 12 cases the cause of death was attributed to the sequelae of profound hypoxemia from inadequate mixing. Contributing factors were prematurity, 41.7%; severe respiratory distress syndrome, 25%; and persistent pulmonary hypertension of the newborn (PPHN), 16.7%. All patients received prostaglandin E1 (PGE1) infusion. Urgent balloon atrial sepstostomy (BAS) was performed in 66.7% with improved oxygenation. No cases were diagnosed prenatally. In contrast, all patients with a PFO < or = 2 mm who survived to ASO had a significantly better response to PGE1 infusion (p=0.03) than nonsurvivors. The ASO was accomplished without mortality in four of nine with a weight <2 kg., Conclusions: Of those neonates admitted with TGA, 4.1% died before surgery. Eleven of 12 (3.7%) died due to consequences of inadequate interatrial mixing despite PGE1 infusion. Earlier diagnosis and BAS are critically important in determining survival. Early ASO may improve survival in patients weighing <2 kg. Prenatal diagnosis with delivery in a high-risk obstetrical unit with facilities for immediate BAS and supportive therapy for pulmonary hypertension and ventricular failure may be necessary to salvage this group of patients.

Objectives: This study was undertaken to investigate the long-term outcome of balloon angioplasty for recurrent coarctation of the aorta in a large series of patients., Background: Balloon angioplasty has become the standard treatment for residual or recurrent aortic coarctation. Despite the widespread use of this treatment modality, there are few data outlining the long-term outcome of a large patient cohort., Methods: Clinical, echocardiographic, hemodynamic and angiographic data on 90 consecutive patients who underwent balloon angioplasty between January 1984 and January 1996 were reviewed., Results: Mean systolic pressure gradients were reduced from 31 +/- 21 to 8 +/- 9 mm Hg after dilation (p = 0.0001). The mean diameter of the stenotic site, measured in the frontal and lateral views, increased by 38% and 35%, respectively (p = 0.001). Neurologic events occurred in two patients, with one death. An aortic tear occurred in one patient, requiring surgical intervention. Optimal results were defined as a postprocedure gradient < 20 mm Hg and were obtained acutely in 88% of patients. At long-term follow-up (12 years), 53 (72%) of 74 patients with an early optimal result remained free from reintervention. Transverse arch hypoplasia, defined as an arch dimension < 2 SD below the mean for age, was the primary predictor of the need for reintervention., Conclusions: Although the majority of patients undergoing percutaneous balloon angioplasty for recoarctation of the aorta will achieve long-term benefit, the need for further surgical intervention in those with transverse arch hypoplasia remains high.

Objectives: We report the clinical course and unique hemodynamic findings after placement of a supraannular mitral valve prosthesis., Background: Children with symptomatic mitral valve disease whose annulus is too small for the smallest prosthesis are difficult to manage. One option is valve replacement with a prosthesis positioned entirely within the left atrium (LA)., Methods: We reviewed 17 patients (median age 10 months) with symptomatic mitral valve disease who underwent placement of a supraannular valve prosthesis between 1980 and 1994., Results: The actuarial survival rates were 88% at 1 month and 71%, 62% and 53% at 1, 2 and 10 years, respectively. Preoperative hemodynamic data (mean +/- SD)) compared with those after placement of the supraannular mitral prosthesis were as follows: "a" wave to left ventricular end-diastolic pressure gradient 17 +/- 5 versus 4 +/- 4 mm Hg (p = 0.003), mean LA pressure 25 +/- 6 versus 20 +/- 6 mm Hg (p = 0.07), "a" wave 30 +/- 6 versus 19 +/- 5 mm Hg (p = 0.006), "v" wave 28 +/- 5 versus 30 +/- 9 mm Hg (p = 0.31), mean pulmonary artery pressure 54 +/- 19 versus 42 +/- 15 mm Hg (p = 0.07) and left ventricular end-diastolic pressure 14 +/- 5 versus 16 +/- 4 mm Hg (p = 0.12)., Conclusions: Supraannular mitral valve replacement provides relief of mitral stenosis or mitral regurgitation. However, LA to left ventricular early diastolic gradients with large atrial "v" waves contribute to elevated mean LA pressures in the absence of prosthetic valve obstruction or regurgitation. As a result of this unexpected finding, associated left heart obstructive lesions and pulmonary and left ventricular end-diastolic hypertension, the outlook remains poor.

Objectives: We investigated the effect of inhaled nitric oxide and infused acetylcholine in patients with pulmonary hypertension undergoing cardiac catheterization before cardiopulmonary transplantation., Background: The fate of patients under consideration for transplantation of the heart or lungs, or both, is influenced by the evaluation of their pulmonary vascular reactivity., Methods: We evaluated 11 patients who were classified into two groups on the basis of mean left atrial pressure > 15 mm Hg (group I, n = 6) or < or = 15 mm Hg (group II, n = 5). All patients inhaled nitric oxide at 80 ppm. This was preceded by an infusion of 10(-6) mol/liter of acetylcholine in seven consecutive patients (n = 3 in group I, n = 4 in group II)., Results: In group I, inhaled nitric oxide decreased pulmonary artery pressure from (mean +/- SE) 71 +/- 13 to 59 +/- 10 mm Hg (p < 0.05), pulmonary vascular resistance from 14.9 +/- 3.8 to 7.6 +/- 1.7 Um2 (p < 0.05) and intrapulmonary shunt fraction from 17.8 +/- 3.6% to 12.7 +/- 2.1% (p < 0.05). Left atrial pressure tended to increase from 27 +/- 4 to 32 +/- 5 mm Hg (p = 0.07). In group II pulmonary vascular resistance decreased in response to nitric oxide from 36.4 +/- 9.0 to 31.1 +/- 7.9 Um2 (p < 0.05). Cardiac index, systemic pressure and resistance did not change in either group. Seven patients who received acetylcholine had no significant alteration in pulmonary hemodynamic variables., Conclusions: These preliminary observations suggest that nitric oxide is a potent pulmonary vasodilator with minimal systemic effects. It may be useful in discriminating patients needing combined heart and lung transplantation from those requiring exchange of the heart alone.

Objectives: The aim of this study was to assess the morphology of the coronary sinus, its drainage and associated cardiac malformations when there is either complete unroofing of the coronary sinus or atresia of its connection to the right atrium., Background: As more children with complex cardiac anomalies are accepted for primary surgical repair or palliation with cavopulmonary anastomoses, a knowledge of coronary sinus and systemic venous anomalies is important if coronary venous return is to be preserved and residual shunts avoided., Methods: Twenty-six heart-lung specimens without a coronary sinus draining to the right atrium were identified from the Leiden collection of congenital heart malformations. These were classified into specimens with an unroofed coronary sinus and those with atresia of the coronary sinus orifice. Attention was paid to the associated cardiac malformations., Results: In 14 (54%; confidence limits [CL] 35%, 73%) of 26 specimens, there was an unroofed coronary sinus, associated with persistence of the left superior caval vein. An inferoposterior location of an atrial septal defect was detected in 2 (14%; CL -4%, 33%) of 14. Atrial appendage anomalies were seen in 13 (93%; CL 79%, 106%) of 14 specimens, exemplified by both right and left isomerism. These were frequently associated with an atrioventricular septal defect (12 [86%; CL 67%, 104%] of 14). An atretic coronary sinus orifice was seen in 12 (46%; CL 27%, 65%) of 26. Atrial appendage anomalies (2 [17%; CL -4%, 38%] of 12) were rare in these cases. The drainage was then by way of a left superior caval vein or, in its absence, a coronary sinus to left atrial window. Ventricular hypoplasia was seen in both categories of coronary sinus abnormalities. Important ventricular hypoplasia was seen in 12 cases (46%; CL 27%, 65%)., Conclusions: These findings emphasize the need to study coronary sinus drainage before procedures such as ligation or transcatheter coil embolization of a left superior caval vein, venous redirection or closure of a dorsal atrial septal defect are contemplated. These procedures might inadvertently lead to impairment of coronary venous return or persistence of an intracardiac shunt.