Chronic thromboembolic pulmonary hypertension (CTEPH) is a complex chronic disease in which pulmonary artery stenosis or obstruction caused by organized thrombus can lead to increased pulmonary artery pressure and pulmonary vascular resistance, ultimately triggering progressive right heart failure and death. Currently, its exact mechanism is not fully understood. Pulmonary endarterectomy (PEA) has immediate effects with low perioperative mortality and satisfactory prognosis in experienced expert centers for CTEPH patients with proximal lesions. Nevertheless, 37% of patients are deemed unsuitable for PEA surgery due to comorbidities and other factors, and nearly half of the operated patients have residual or recurrent pulmonary hypertension. Riociguat is the only approved drug for CTEPH, although its effect is limited. Balloon pulmonary angioplasty (BPA) is a promising alternative treatment for patients with CTEPH. After more than 30 years of development and refinements, emerging evidence has confirmed its role in patients with inoperable CTEPH or residual/recurrent pulmonary hypertension, with acceptable complications and comparable long-term prognosis to PEA. This review summarizes the pathophysiology of CTEPH, BPA history and development, therapeutic principles, indications and contraindications, interventional procedures, imaging modalities, efficacy and prognosis, complications and management, bridging and hybrid therapies, ongoing clinical trials and future prospects.

Pulmonary artery size is a crucial determinant of hemodynamic energy loss in total cavopulmonary connections. We investigated the effect of aortic arch reconstruction on left pulmonary artery size based on their anatomic proximity.

Thirty-two patients undergoing the Fontan operation, 16 with hypoplastic left heart syndrome and 16 with non-hypoplastic left heart syndrome, were selected from the multicenter Fontan magnetic resonance imaging database at the Georgia Institute of Technology. The 16 datasets were consecutive with full anatomic reconstructions of the total cavopulmonary connection and aortic arch with no artifacts. The size of the aorta along the transverse arch and left pulmonary artery size in the region below the aortic arch was quantified by using a previously validated skeletonization technique.

The transverse aortic and left pulmonary artery measurements (median, maximum, and minimum, respectively) for non-hypoplastic left heart syndrome were 2.2, 3.1, and 1.5 cm/m and 1.2, 1.6, and 0.2 cm/m, respectively, compared with 2.5, 4.1, and 2.0 cm/m and 0.9, 1.5, and 0.4 cm/m for patients with hypoplastic left heart syndrome. Thus the transverse aortic diameter of patients with hypoplastic left heart syndrome was, on average, 24% greater than that for patients with non-hypoplastic left heart syndrome (P < .05), whereas the left pulmonary artery diameter of patients with hypoplastic left heart syndrome was smaller than that of patients with non-hypoplastic left heart syndrome (P < .05). Regression analysis showed a significant negative correlation (P < .05) between aortic and left pulmonary artery diameters in both the hypoplastic left heart syndrome and non-hypoplastic left heart syndrome groups. However, when the study population was regrouped into reconstructed aorta and nonreconstructed aorta groups, the negative correlation was only significant for patients with reconstructed aortas, regardless of ventricular pathology (P < .02).

Stage 1 aortic reconstruction procedures that result in a large aorta limit left pulmonary artery size in patients undergoing the Fontan operation.

Despite the increasing recognition of thromboembolic complications of the Fontan procedure, data characterizing such events are limited. The total cavopulmonary connection is believed to be less prone to this complication than other modifications of Fontan operations. We examined our experience with thromboembolism after Fontan operations to better characterize these events and their relation to the type of Fontan operation performed.

We retrospectively identified 70 patients who underwent a Fontan operation between January 1978 and March 1994. Patients were divided into three groups: (1) total cavopulmonary connection, (2) atriopulmonary connection, and (3) conduit interposition. Fourteen patients (20%) developed a thromboembolic complication during a mean (+/- SD) follow-up of 5.2 +/- 4.7 years. The rate of thrombosis was similar in each group. The time from Fontan operation to thrombosis averaged 6.1 +/- 5.0 years. The overall rate of thromboembolic events was 3.9 per 100 patient-years. Twelve of the 14 thrombi were located within the venous circulation, 1 was in the left ventricle, and the location of 1 was undetermined. Six of the patients (43%) were asymptomatic, 3 (21%) presented with cerebrovascular events, and 5 (36%) presented with other symptoms. Thromboembolic events occurred from the perioperative period to 15 years after surgery.

Thromboembolic complications occur frequently after the Fontan operation and its modifications and are a cause of significant morbidity. The time of presentation varies greatly. The rate of thrombosis appears to be similar in all modifications of the Fontan operation.

Transesophageal echocardiography demonstrated six instances of venous thrombus formation in the inferior vena cava, right atrium and caval-pulmonary anastomosis region in four children after a modified Fontan operation. Transthoracic surface echocardiography failed to identify these thrombi in five of the six cases because of the posterior location of the thrombus or imaging interference from surgical hardware. These thrombotic episodes occurred 2 days to 5 years after the Fontan operation in children 25 to 168 months of age. Clinical features of compromised cardiac performance with cyanosis or inadequate perfusion were present during four of the six episodes. In two patients, thrombi occurred around transvenous permanent atrial pacing leads. Therapy to eliminate thrombus included surgery (two cases), anticoagulation with warfarin (three cases) and streptokinase thrombolysis (one case). Disappearance of the thrombus was confirmed by transesophageal study in three of the four cases with follow-up echocardiography. Transesophageal echocardiographic demonstration of atrial and pulmonary thrombi that could not be seen by transthoracic imaging suggests that these thrombi occur with greater frequency in patients who have undergone the Fontan operation than was previously suspected.

Transesophageal echocardiography with Doppler examination was performed intraoperatively in 19 children undergoing modified Fontan operations and in 10 patients postoperatively. Comparisons were made with results of intraoperative epicardial imaging (9 patients) and with postoperative transthoracic imaging (10 patients). Transesophageal echocardiography optimally visualized atriopulmonary and cavopulmonary anastomoses. Epicardial echocardiography was successful in only three of nine patients. Intraoperative transesophageal echocardiography showed residua in 8 of 19 studies and led directly to surgical revision or medical therapy. These residua included stenosis of the cavopulmonary anastomosis (1 patient), unsatisfactory atrial fenestration (2 patients), patent ductus arteriosus (1 patient), residual cavoatrial shunting (1 patient), atrial thrombi (1 patient), and poor ventricular function (2 patients). Results of examination in the postoperative intensive care unit showed significant abnormalities in 4 of 10 patients. This study demonstrates that transesophageal echocardiography provides unique anatomic and physiologic information during and after modified Fontan operations in small children and therefore may have significant impact on patient management.

Two hundred eighteen balloon angioplasty procedures were performed in 135 patients with branch pulmonary artery stenoses from June 1984 to February 1989. Arteries were dilated in patients with tetralogy of Fallot (n = 49), tetralogy of Fallot/pulmonary atresia (n = 64), isolated peripheral pulmonary artery stenoses (n = 58) and "other" lesions (the majority had truncus arteriosus or single ventricle and surgically induced pulmonary artery stenoses (n = 47). Mean age at dilation was 6.6 +/- 6.3 years (range 1 month to 38.5 years). The mean diameter of the lesion increased from 3.8 +/- 1.7 to 5.5 +/- 2.1 mm with dilation (p = 0.001). The overall success rate was 58% (127 of 218 dilations), assessed by the following criteria: an increase greater than or equal to 50% of predilation diameter, an increase greater than 20% in flow to the affected lung or a decrease greater than 20% in systolic right ventricular to aortic pressure ratio. Success did not correlate with patient age. Mean balloon to artery ratio was higher in successful (4.2) than in failed (3.0) angioplasty procedures (p = 0.0001). There were four early deaths: two of the patients had pulmonary artery rupture with angioplasty performed less than 1 month after pulmonary artery surgery. An aneurysm occurred in 11 arteries and transient pulmonary edema in four patients. At angiography performed a mean of 10 months (range 1 to 54) after dilation, the mean diameter of 57 arteries was unchanged (5.5 versus 5.4 mm). However, 5 of 32 initially successfully dilated vessels had returned to predilation size as a result of restenosis.(ABSTRACT TRUNCATED AT 250 WORDS)

The present status of catheter-directed therapy in pediatric congenital and acquired heart disease is reviewed. Balloon pulmonary valvotomy, established as the procedure of choice for children and adults with isolated pulmonary stenosis, has now been extended to neonates with critical pulmonary stenosis. Balloon mitral and aortic valvotomy are being performed for congenital and acquired stenoses, although indications and optimal techniques remain to be established. Balloon angioplasty of coarctation effectively relieves obstruction in native and post-operative aortic arch stenoses, but remains controversial due to late aneurysm formation. Balloon angioplasty of branch pulmonary artery hypoplasia and stenosis, despite a relatively low success rate and significant complications, remains the procedure of choice due to lack of better therapeutic options. Transcatheter closure of congenital and acquired vessels and defects is being performed with increasing frequency. Embolization of aortopulmonary collaterals and shunts using Gianturco coils is safe and effective in selected patients. Although Rash-kind umbrellas are most commonly used for closure of a patent ductus arteriosus, their use, especially in closing intracardiac defects, remains investigational.