Hypoplastic left heart syndrome: hemodynamic and angiographic assessment after initial reconstructive surgery and relevance to modified Fontan procedure

After undergoing initial reconstructive surgery for hypoplastic left heart syndrome performed between August 1985 and March 1989, 59 patients (age range 3 to 27 months, mean 13.8 +/- 4.5) underwent elective cardiac catheterization in anticipation of a modified Fontan procedure. Five important hemodynamic and anatomic features considered to be components of successful reconstructive surgery were specifically addressed. 1) Interatrial communication: Only two patients had a measured pressure difference of greater than 4 mm Hg across the atrial septum. 2) Tricuspid valve function: Angiography demonstrated significant tricuspid valve regurgitation in only five patients (moderate in two and severe in three). 3) Aortic arch: Pressure tracings from the right ventricle to the descending aorta revealed a gradient greater than 25 mm Hg in only two patients. 4) Pulmonary vasculature: Ten patients had a calculated pulmonary vascular resistance greater than 4 U.m2; 51 (86%) of the 59 patients had no evidence of distortion (stenosis or hypoplasia) of either the left or the right pulmonary artery. 5) Right ventricular function: Five patients had an end-diastolic pressure in the right ventricle greater than 12 mm Hg and two patients had qualitative assessment of decreased ventricular function. Comparison of catheterization data between survivors and nonsurvivors of the subsequent modified Fontan procedure showed that only significant tricuspid regurgitation is a possible predictor of poor outcome. After first stage reconstructive surgery for hypoplastic left heart syndrome, most survivors have favorable anatomy and hemodynamics at follow-up cardiac catheterization for a subsequent Fontan procedure.     

Caveats of balloon dilation of conduits and conduit valves

The results and complications of percutaneous balloon dilation involving 10 patients with a stenotic right ventricle to pulmonary artery prosthetic conduit and 1 patient with an obstructed right atrium to left pulmonary artery Dacron graft (modified Fontan) are reported. For the 10 patients (14.5 +/- 5 years) with a right ventricle to pulmonary artery conduit, the mean (+/- SD) predilation conduit valve gradient was 57 +/- 22 mm Hg, right ventricular pressure 104 +/- 21 mm Hg and right ventricle to pulmonary artery gradient 75 +/- 23 mm Hg; 2 of the patients had additional pulmonary artery stenosis requiring dilation. In one patient, the balloon could not be advanced across the conduit valve. In 9 of 10 patients in whom dilation was successfully performed, the conduit valve gradient decreased by 59 +/- 13%, right ventricle to pulmonary artery gradient by 43 +/- 22% and right ventricular pressure by 31 +/- 11%. After dilation, right ventricular pressure was less than 65% of systemic pressure in seven patients, although no pressure was less than 40%. In 8 of the 11 patients, surgery was avoided or postponed. Complications included loss of a balloon fragment after rupture during the unsuccessful dilation of the right atrium to left pulmonary artery graft and circumferential balloon rupture requiring catheter retrieval of the distal portion of the balloon from the femoral vein after successful dilation of the right ventricle to pulmonary artery conduit. Conduit valve dilation by balloon can reduce but rarely eliminate conduit obstruction, and balloon rupture may occur and can result in fragment loss or embolization.     

A quantitative analysis of hemodynamic effects of the right ventricle included in the circulation of the Fontan procedure

BACKGROUND. Right heart hemodynamics were analyzed with a catheter-mounted velocity meter in seven patients after direct atrioventricular anastomosis for Fontan procedure (RV group) and were compared with those obtained in eight patients after direct atriopulmonary anastomosis (RA group). METHODS AND RESULTS. In the RV group, cardiac output was 2.7 +/- 0.6 l/min/m2; mean right atrial and pulmonary artery pressures were both 13 +/- 3 mm Hg; mean pulmonary artery wedge pressure was 7 +/- 5 mm Hg; left ventricular end-diastolic volume, determined angiographically, was 129 +/- 40% of normal; and its ejection fraction was 0.50 +/- 0.09. In the RA group, data were similar to those of the RV group except that right heart pressure were lower in the RV group, which was related to the preoperative condition of the pulmonary circulation. In the RV group, the fraction of ventricular forward flow of the total forward flow in the main pulmonary artery ranged from 0.21 to 0.46 and was not correlated with cardiac output or with any other parameter. The backward flow into the inferior vena cava at ventricular systole was greater than the atrial flow in two patients in whom cardiac output was less than 2.2 l/min/m2, whereas caval backward flow at atrial contraction was greater than ventricular flow in the other five patients, of whom four had a cardiac output greater than 3.1 l/min/m2. CONCLUSIONS. We conclude that the inclusion of right ventricle in the circulation of the Fontan procedure does not necessarily improve overall hemodynamics in most patients.     

Noninvasive estimation of pulmonary artery diastolic pressure in patients with tricuspid regurgitation by Doppler echocardiography.

OBJECTIVES: The purpose of this study was to determine whether Doppler echocardiographic assessment of right ventricular pressure at the time of pulmonary valve opening could predict pulmonary artery diastolic pressure. BACKGROUND: Doppler echocardiography has been used to estimate right ventricular systolic pressure noninvasively. Because right ventricular and pulmonary artery diastolic pressure are equal at the time of pulmonary valve opening, Doppler echocardiographic estimation of right ventricular pressure at this point might provide an estimate of pulmonary artery diastolic pressure. METHODS: We studied 31 patients who underwent right heart catheterization and had tricuspid regurgitation. Pulmonary flow velocity was recorded by pulsed wave Doppler echocardiography, and tricuspid regurgitant velocity was recorded by continuous wave Doppler echocardiography. The time of pulmonary valve opening was determined as the onset of systolic flow in the pulmonary artery. Tricuspid velocity at the time of pulmonary valve opening was measured by superimposing the interval between the onset of the QRS complex on the ECG and the onset of pulmonary flow on the tricuspid regurgitant envelope. The tricuspid gradient at this instant was calculated from the measured tricuspid velocity using the Bernoulli equation. This gradient was compared to the pulmonary artery diastolic pressure obtained by right heart catheterization. MEASUREMENTS AND RESULTS: The pressure gradient between the right atrium and right ventricle obtained at the time of pulmonary valve opening ranged from 9 to 31 mm Hg (mean, 19+/-5) and correlated closely with invasively measured pulmonary artery diastolic pressure (range, 9 to 36 mm Hg; mean, 21+/-7 mm Hg; r = 0.92; SEE, 1.9 mm Hg). CONCLUSION: Doppler echocardiographic measurement of right ventricular pressure at the time of pulmonary valve opening is a reliable noninvasive method for estimating pulmonary diastolic pressure.     

Surgical evaluation of the modified Fontan procedure.

From 1980 to 1990 152 patients underwent Fontan operation at our institution. The following patient groups were identified: 1. patients with tricuspid atresia (n = 82, 54.0%); 2. patients with single ventricle (n = 31, 20.3%); 3. patients with a wide variety of non correctable, complex cardiac malformations (n = 39, 25.7%). In 27.0% of the patients a primary Fontan operation was performed. 45.0% of the patients received a previous shunt to increase pulmonary blood flow and in 29.4% of the patients a pulmonary artery band was placed to reduce pulmonary flow. Overall mortality was not significantly different in patients with previous palliative procedures (19.4%, n = 18) as compared to 17.4% (n = 6) in patients with primary Fontan operation. Risk of death was high in the group with complex cardiac malformations (28.2%, n = 11) and in patients with single ventricle (19.4%, n = 6). Early mortality was considerably less in patients tricuspid atresia (8.5%, n = 7). Postoperatively patients with incorporation of the residual right ventricular chamber and pulmonary valve (Fontan-Bjoerk) showed a significant (p less than 0.05) lower incidence of pleural effusion as compared to patients with other modifications of the Fontan procedure. Actuarial survival rate of all patients is 83.8 +/- 3.1% (mean +/- SEM) at ten years. The modified Fontan procedures are providing an accepted surgical method for patients with otherwise non correctable cardiac malformations.     

Percutaneous transluminal balloon valvuloplasty for pulmonary valve stenosis

Transluminal balloon valvuloplasty was used to treat congenital pulmonary valve stenosis in 20 patients. Follow-up cardiac catheterization was performed in 11 patients at intervals of from 2 to 12 months after the procedure. Peak systolic pressure gradient across the pulmonic valve decreased from 68 +/- 27 to 23 +/- 5 mm Hg (p less than .001) after valvuloplasty. There were no complications. Follow-up catheterization demonstrated persistent relief of right ventricular hypertension in the patients with typical pulmonary valve stenosis.     

Long-term results after balloon pulmonary valvuloplasty

BACKGROUND. The objective of this study was to determine the long-term outcome of patients after percutaneous balloon pulmonary valvuloplasty (BPV) treatment of congenital pulmonary valve stenosis. METHODS AND RESULTS. This study represents a case series with duration (mean +/- SD) of follow-up of 4.6 +/- 1.9 years. Forty-six patients with a median age of 4.6 years (range, 3 months to 56 years) had BPV at one academic institution between June 1981 and December 1986. Mean peak systolic pressure gradients from the right ventricle to the pulmonary artery were as follows: before BPV, 70 +/- 36 mm Hg; immediately after BPV, 23 +/- 14 mm Hg; at intermediate follow-up by cardiac catheterization or Doppler echocardiography at less than 2 years after BPV, 23 +/- 16 mm Hg (n = 33); and at long-term follow-up by Doppler at more than 2 years after BPV, 20 +/- 13 mm Hg (n = 42). BPV acutely reduced the gradient to less than 36 mm Hg for 41 of 46 (89%) patients. Available gradients at long-term follow-up were less than 36 mm Hg for 36 of 42 (86%) patients without additional procedures. A patient age of less than 2 years at the initial BPV was a significant risk factor for gradients over 36 mm Hg at follow-up. CONCLUSIONS. BPV provides long-term relief of pulmonary valvular obstruction in the majority of patients. Close follow-up of patients who require BPV at less than 2 years of age is warranted.     

Hemodynamic assessment after palliative surgery for hypoplastic left heart syndrome

Ten patients with hypoplastic left heart syndrome underwent cardiac catheterization to assess the effectiveness of palliative surgery designed to prepare them for a modified Fontan procedure. The objectives of palliation were to establish unobstructed systemic blood flow, normalize pulmonary blood flow and pressure, and relieve pulmonary venous obstruction. In the first four patients, systemic blood flow from the right ventricle was established by means of a conduit from either the right ventricular free wall or the proximal main pulmonary artery to the thoracic aorta. Pulmonary blood flow was limited by pulmonary artery banding and ligation of the ductus arteriosus in three patients and by a Blalock-Taussig shunt in one. Conduit obstruction of systemic blood flow developed in two of these infants, and pulmonary vascular abnormalities precluded reparative surgery in the other two. In the other six patients, systemic blood flow was established by direct anastomosis of the proximal main pulmonary artery to the ascending aorta and aortic arch. The pulmonary vasculature was protected by providing pulmonary flow through a central or Blalock-Taussig shunt. The interatrial communication was enlarged by atrial septectomy or balloon atrial septotomy. One infant had progressive tricuspid regurgitation necessitating valve replacement. One, in whom balloon atrial septotomy had been performed, developed an obstructive interatrial communication necessitating late atrial septectomy. These six patients were candidates for physiologic correction. To date, three patients have undergone a modified Fontan procedure; two are clinically well at 9 and 12 months after surgery. Three patients await this procedure.     

Complete transposition of the great arteries: surgical concepts for patients with systemic right ventricular failure following intraatrial repair

One of the most serious late complications of the intraatrial baffle procedure (Mustard or Senning correction) in patients suffering from transposition of the great arteries, (TGA) is the late systemic right ventricular failure. Nearly all patients presenting with right ventricular dysfunction have severe associated tricuspid regurgitation. The surgical options for these patients include tricuspid valve reconstruction or replacement, staged conversion to the arterial switch operation and orthotopic heart transplantation. Review of 189 operative survivors who underwent the Mustard or Senning operation for TGA between 1970 and 1993 in our institution revealed 12 patients (6.3%) who died from severe systemic right ventricular dysfunction (mean follow-up 16+/-3.5 years), which was the most common cause of late death. All of them had concomitant severe tricuspid regurgitation. 7 patients (3.7%) died from sudden cardiac death. The actuarial survival at 10 years is 93% for simple TGA and 85% for TGA associated with ventricular septum defect or coarctation. At our institution, 4 adolescent or adult patients underwent tricuspid valve surgery; tricuspid valve replacement was performed in 2 patients and valve repair in 2 patients. In the mid-term follow-up, 2 of these patients died. Two additional patients underwent orthotopic heart transplantation, and one died on the waiting list. Staged conversion from the Senning/Mustard atrial repair to the arterial switch operation was initially reported by Mee. The procedure for pulmonary artery banding starts with inducing left ventricular reconditioning with subsequent arterial switch. The mortality of this two-staged procedure was as high as 20% to 30% in our early experience, and some of the candidates underwent heart transplantation. Tricuspid valve repair or replacement do not improve right ventricular function in patients with a failing right ventricle following the Mustard/Senning operation. Staged conversion to arterial switch may improve right ventricular function by decreasing the work load of the right ventricle and provides anatomic repair with left ventricle-to-aorta continuity. Orthotopic heart transplantation is the only alternative if the left ventricle does not respond to pulmonary artery banding.     

Motion analysis of the Carpentier ring in the tricuspid position: an echocardiographic and hemodynamic study

The echocardiographic and hemodynamic results before and after (30 +/- 4 months) mitral valve replacement and tricuspid valvuloplasty using a Carpentier ring were compared in 37 patients. The motion of the Carpentier ring in the echocardiogram was related to the pulmonary artery pressure curve and the intracardiac phonocardiogram for exact temporal relation. Pressure measurements were done using a tip micromanometer. Postoperatively 29 patients were clinically improved showing a decrease of the mean pulmonary artery pressure from 63 +/- 14 mm Hg to 41 +/- 18 mm Hg (p less than 0.001) as well as of the right atrial pressure from 13 +/- 4 mm Hg to 8 +/- 3 mm Hg (p less than 0.01). The postoperative decrease of the opening amplitude of the septal tricuspid leaflet from 22 +/- 3 mm to 10 +/- 4 mm (p less than 0.001) and of the EF-slope from 125 +/- 45 mm/s to 34 +/- 41 mm/s (p less than 0.001) in 9 patients was a sign of an inflow obstruction in the right ventricle. During the synchronous pressure measurement in the right ventricle and in the right atrium, a mean diastolic pressure gradient of 3.9 +/- 1.4 mm Hg was registered postoperatively in these patients. Five patients showed persisting right heart failure, in one a severe tricuspid regurgitation was still present, in 4 patients the pressure gradient exceeded 5 mm Hg.(ABSTRACT TRUNCATED AT 250 WORDS)     

Special problems in Fontan-type operations for complex cardiac lesions

Four patients with complex cardiac lesions, who underwent successfully a Fontan type of operation are presented, each case representing a particular problem in surgical management. The first exhibited displacement of a trileaflet straddling and overriding left atrioventricular valve in addition to tricuspid atresia, while the second one had unilateral lung perfusion. In the third case, a stenosis had developed near the origin of the right pulmonary artery, and pulmonary vascular resistance could not be determined prior to the definite palliation procedure, whereas the fourth patient presented with stenosis of the left atrioventricular valve. Surgery was planned after detailed evaluation of the morphologic and hemodynamic features by means of echocardiography and cardiac catheterization. Our results illustrate the common tendency to extend the limits for modified Fontan procedures, which also includes revision of the original criteria for selection.     

Functional assessment of the Fontan operation: combined M-mode, two-dimensional and Doppler echocardiographic studies

Combined M-mode, two-dimensional and Doppler echocardiographic studies were used to assess the postoperative status of 33 patients who had undergone the modified Fontan procedure. Twenty-four patients had surgical repair with use of a simple direct right atrium to pulmonary artery anastomosis. The remaining patients had repair with use of a prosthesis or associated Glenn shunt. Twenty-seven patients were studied early in the postoperative period (2 months or less) and the remaining patients were studied up to 6 years postoperatively. A total of 36 examinations were performed. Of the 33 patients, 13 had tricuspid atresia, 12 had double inlet left ventricle with hypoplastic right ventricular outlet chamber and 8 had complex lesions with atrioventricular canal, double outlet right ventricle or a hypoplastic ventricle. Postoperative assessment by M-mode and two-dimensional echocardiography demonstrated normal or mildly reduced ventricular function (ejection fraction greater than 40%) in 22 patients. In 24 patients, a "normal" flow pattern was observed in the pulmonary artery by pulsed Doppler echocardiography, with predominant diastolic flow and accentuation by atrial systole somewhat similar to the venous flow pattern observed in the superior vena cava. "Abnormal" flow patterns (disorganized systolic flow, absence of atrial waves and little or no increase with inspiration) were observed in nine patients with reduced ventricular function or residual shunt. Continuous wave Doppler study also demonstrated mild dynamic subaortic obstruction in two patients. Combined pulsed and continuous wave studies showed atrioventricular valve insufficiency in 10 patients. Follow-up studies revealed a satisfactory clinical course in most patients. Three patients died approximately 4 to 8 months after their Fontan operation.     

Can echocardiographic evaluation of cardiopulmonary hemodynamics decrease right heart catheterizations in end-stage heart failure patients awaiting transplantation?

Candidacy for heart transplantation is influenced by the severity of pulmonary hypertension. In this study, invasive hemodynamics from right-sided cardiac catheterization were compared with values obtained by validated equations from Doppler 2-dimensional transthoracic echocardiography. This prospective study was conducted in 40 patients with end-stage heart failure evaluated for heart transplantation or ventricular assist device implantation. Transthoracic echocardiography and right-sided cardiac catheterization were performed within 4 hours. From continuous-wave Doppler of the tricuspid regurgitation jet, pulmonary artery systolic pressure was calculated as the peak gradient across the tricuspid valve plus right atrial pressure estimated from inferior vena cava filling. Mean pulmonary artery pressure was calculated as (0.61 × pulmonary artery systolic pressure) + 2. Pulmonary vascular resistance (PVR) was calculated as (tricuspid regurgitation velocity/right ventricular outflow tract time-velocity integral × 10) + 0.16. Pulmonary capillary wedge pressure was calculated as 1.91 + (1.24 × E/E'). Pearson's correlation and Bland-Altman analysis of mean differences between echocardiographic and right-sided cardiac catheterization measurements were statistically significant for all hemodynamic parameters (pulmonary artery systolic pressure: r = 0.82, p < 0.05, mean difference 3.1 mm Hg, 95% confidence interval [CI] -0.2 to 6.3; mean pulmonary artery pressure: r = 0.80, p < 0.05, mean difference 2.5 mm Hg, 95% CI 0.3 to 4.6; PVR: r = 0.52, p < 0.05, mean difference 0.8 Wood units, 95% CI 0.3 to 1.4; pulmonary capillary wedge pressure: r = 0.65, p < 0.05, mean difference 2.2 mm Hg, 95% CI 0.1 to 4.3). Compared with right-sided cardiac catheterization, PVR by Doppler echocardiography identified all patients with PVR > 4 Wood units (n = 4), 73% of patients with PVR <2 Wood units (n = 8), and 52% of patients with PVR from 2 to 4 Wood units (n = 10). In conclusion, echocardiographic estimation of cardiopulmonary hemodynamics is reliable in patients with end-stage cardiomyopathy. The noninvasive assessment of hemodynamics by echocardiography may be able to decrease the number of serial right-sided cardiac catheterizations in selected patients awaiting heart transplantation. However, in patients with borderline PVR, right-sided cardiac catheterization is indicated to assess eligibility for transplantation.     

Transatrial resection of the obstructed right ventricular infundibulum.

Obstructions of the right ventricular infundibulum were resected through the orifice of the tricuspid valve in 21 patients, 15 of whom had tetralogy of Fallot. At operation the systolic pressure difference between the right ventricle and pulmonary artery after repair averaged 18 mm Hg (range 0-40 mm Hg). In patients with tetralogy, cardiac index four hours after operation averaged 2.8 L/M2/min. One patient with tetralogy and severe pulmonary hypertension died. Twelve patients with tetralogy were recatheterized 10 to 186 days after operation. The mean systolic pressure difference between right ventricle and pulmonary artery was 23 mm Hg. Residual obstructions were in the pulmonary valvular annulus. Cineangiograms did not show paradoxical motion of the right ventricular wall. Transatrial resection of right ventricular infundibular obstructions carries with it none of the consequences that often follow right ventriculotomy and this surgical approach satisfactorily relieves infundibular obstructions.     

Echocardiographic and hemodynamic evaluation of carpentier tricuspid valvuloplasty

To study the long-term results of tricuspid valvuloplasty, pre- and postoperatively (39 +/- 11 months), echocardiographic and catheterization data were collected in 37 patients (mean age, 58 +/- 8 years). Because of severe mitral stenosis, all patients received a porcine heterograft in the mitral position and underwent reconstructive tricuspid surgery with Carpentier rings (#32, n = 12; #34, n = 15; #36, n = 10). Sizing was performed by measuring the anterior leaflet area using an obturator. In nine patients, tricuspid leaflets were slightly shrunken at the insertion site of the chordae tendineae. Postoperative echocardiography and right heart catheterization were performed with simultaneous pressure recordings in the right ventricle and right atrium. A significant clinical improvement was noted in 24 patients, and this correlated with significant hemodynamic improvement. In eight patients, no clinical improvement was observed. Patients were divided into subgroups according to echocardiographic and hemodynamic criteria. Group A (n = 17) was composed of patients with significant improvement of hemodynamics, without detectable tricuspid valve dysfunction. Group B (n = 11) was composed of patients with slight-to-moderate tricuspid incompetence, detected by contrast echocardiography. In nine of these patients, the size of the RA and the diameter of the IVC were significantly smaller than preoperatively. In patients of Group C, echocardiography and catheterization data showed a slight-to-moderate tricuspid stenosis with a mean diastolic pressure gradient of 3.9 +/- 1.4 mm Hg (max 6.2 mm Hg, min 2.4 mm Hg). Although the area of the anterior tricuspid leaflet was slightly underestimated, we determined that long-term results of tricuspid valve annuloplasty with a Carpentier ring were encouraging.     

Transcatheter closure of atrial septal defects in children with a hypoplastic right ventricle.

The efficacy and safety of device closure of atrial defects in children with complex congenital heart disease and a hypoplastic right ventricle have not been detailed. The objective of this study was to determine the clinical impact and outcomes of a staged surgical catheter-based management strategy. A retrospective analysis of 17 children with a hypoplastic right ventricle who had undergone cardiac catheterization and attempted device occlusion of an atrial defect was undertaken. Clinical data, anatomical diagnoses, previous surgeries, and interventions were noted. The clinical course and echocardiographic findings were compared before and after defect closure (6 +/- 4 months of follow-up). Nine children had pulmonary atresia with an intact ventricular septum, six had Ebstein's anomaly of the tricuspid valve, and two had isolated right ventricular hypoplasia. The mean age at defect closure was 6.6 +/- 3.4 years. Under general anesthesia, closure of the atrial defect was undertaken after initial temporary test occlusion. The Qp:Qs ratio before closure was 1.1 +/- 0.4. Oxygen saturation improved in all children from 91% +/- 1% to 98% +/- 1% (P < 0.0005). Mean right atrial pressure increased from 9 +/- 3 to 11 +/- 4 mm Hg after closure, but the difference was not statistically significant (P = 0.2). Follow-up revealed an increased right ventricular length (P = 0.009) and Z-score (P = 0.02), although no significant increase in the diameter of the tricuspid valve annulus was observed in children with pulmonary atresia. Right ventricular systolic pressures or systolic function did not change significantly during follow-up (P = 0.5 and 0.29, respectively). Exercise tolerance improved in all children and clinical evidence of right ventricular decompensation was absent. Catheter closure of atrial defects in children with a hypoplastic right ventricle is well tolerated, safe, and effective as a treatment strategy in the staged management.     

Partial and transient relief of conduit obstruction by low-pressure balloon dilation in patients with congenital heart disease

Seven patients underwent attempted low pressure balloon dilation of stenotic conduits or homografts from right ventricle to pulmonary artery (n=5), in the aortic valve position (n=1), or from right atrium to left pulmonary artery (n=1). In the right ventricle to pulmonary artery group, mean gradient reduction was only 17%. At follow-up, two patients underwent surgical conduit replacement, one had a stent implanted at cardiac catheterization, the other two are awaiting surgical intervention. The patient with a homograft in the aortic valve position had a good initial result but restenosed within 1 year and underwent a pulmonary autograft operation. The patient with the Fontan homograft stenosis had transient obstruction relief but subsequently required stent implantation. Low-pressure balloon dilation of conduits or homografts is only partially and transiently successful. Whether stent implantation will offer better long-term results remains to be determined.     

Straddling mitral valve with hypoplastic right ventricle, crisscross atrioventricular relations, double outlet right ventricle and dextrocardia: morphologic, diagnostic and surgical considerations

The clinical, surgical and morphologic findings in five cases of a rare form of straddling mitral valve are presented. Three patients were diagnosed by two-dimensional echocardiography, cardiac catheterization and angiocardiography and two had diagnostic confirmation at autopsy. All five cases shared a distinctive and consistent combination of anomalies: 1) dextrocardia; 2) visceroatrial situs solitus, concordant ventricular D-loop and double outlet right ventricle with the aorta positioned to the left of and anterior to the pulmonary artery; 3) hypoplasia of right ventricular inflow (sinus) with tricuspid valve stenosis or hypoplasia; 4) large right ventricular infundibulum (outflow); 5) malalignment conoventricular septal defect; 6) straddling mitral valve with chordal attachments to the left ventricle and right ventricular infundibulum; 7) severe subpulmonary stenosis with well developed pulmonary arteries; and 8) superoinferior ventricles with crisscross atrioventricular (AV) relations. The degree of malalignment between the atrial and ventricular septa was studied quantitatively by measuring the AV septal angle projected on the frontal plane. The AV septal angle in the two postmortem cases was 150 degrees, reflecting marked malalignment of the ventricles relative to the atria. This AV malalignment appears to play an important role in the morphogenesis of straddling mitral valve. As judged by a companion study of seven postmortem cases, the more common form of straddling mitral valve with a hypertrophied and enlarged right ventricular sinus had less severe ventricular malposition than did the five rare study cases with hypoplastic right ventricular sinus. A competent mitral valve, low pulmonary vascular resistance and low left ventricular end-diastolic pressure were found at cardiac catheterization in the three living patients who underwent a modified Fontan procedure and are doing well 2.2 to 5.8 years postoperatively.     

Comparison of three Doppler ultrasound methods in the prediction of pulmonary artery pressure

Pulmonary artery pressure was noninvasively estimated by three Doppler echocardiographic methods in 50 consecutive patients undergoing cardiac catheterization. First, a systolic transtricuspid gradient was calculated from Doppler-detected tricuspid regurgitation; clinical jugular venous pressure or a fixed value of 14 mm Hg was added to yield systolic pulmonary artery pressure. Second, acceleration time from pulmonary flow analysis was used in a regression equation to derive mean pulmonary artery pressure. Third, right ventricular isovolumic relaxation time was calculated from Doppler-determined pulmonary valve closure and tricuspid valve opening; systolic pulmonary artery pressure was then derived from a nomogram. In 48 patients (96%) at least one of the methods could be employed. A tricuspid pressure gradient, obtained in 36 patients (72%), provided reliable prediction of systolic pulmonary artery pressure. The prediction was superior when 14 mm Hg rather than estimated jugular venous pressure was used to account for right atrial pressure. In 44 patients (88%), pulmonary flow was analyzed. Prediction of mean pulmonary artery pressure was unsatisfactory (r = 0.65) but improved (r = 0.85) when only patients with a heart rate between 60 and 100 beats/min were considered. The effect of correcting pulmonary flow indexes for heart rate was examined by correlating different flow indexes before and after correction for heart rate. There was a good correlation between corrected acceleration time and either systolic (r = -0.85) or mean (r = -0.83) pulmonary artery pressure. Because of a high incidence of arrhythmia, right ventricular relaxation time could be determined in only 11 patients (22%). Noninvasive prediction of pulmonary artery pressure is feasible in most patients.(ABSTRACT TRUNCATED AT 250 WORDS)     

Nonobstructive ASD creation to qualify patients for the Fontan operation: effects on pulmonary hypertension due to restrictive left atrioventricular valve and interatrial communication.

Pulmonary hypertension (PH) due to elevated left atrial pressure (LAp) caused by restrictive left atrioventricular valve and interatrial communication sometimes precludes patients with univentricular heart from undergoing the Fontan operation. We have created atrial septal defect (ASD) for such patients to reduce LAp and then pulmonary arterial pressure (PAp) and pulmonary vascular resistance (Rp) in an attempt to qualify the patients for the Fontan repair. This study was performed to clarify the efficacy and limitation of this approach. Twelve patients with PH (mean PAp > 20 mm Hg and/or Rp > 3.0 Wood's unit/m(2)) due to obstruction at the LA exit underwent ASD creation at the age of 4.0 +/- 4.0 (mean +/- SD) years. Follow-up catheterization 14.9 +/- 15.6 months after the ASD creation demonstrated marked reductions in mean LAp (from 21 +/- 5 to 8 +/- 2 mm Hg), mean PAp (from 39 +/- 13 to 17 +/- 4 mm Hg), and Rp (from 6.2 +/- 4.5 to 2.7 +/- 1.4 Wood's unit/m(2)) compared with those before the procedure (all P < 0.0001). Seven of the 12 patients (58%) qualified for the Fontan operation (mean PAp < 20 mm Hg, Rp < 3.0 Wood's unit/m(2), and Nakata's PA index > or = 250) after the ASD creation. Final surgical outcomes of the seven patients included successful Fontan operation in five and biventricular repair in two. Patients with severe PH [mean PAp > or = 45 mm Hg (n = 6) or Rp > or = 4.5 Wood's unit/m(2) (n = 5)] before the ASD creation qualified less frequently for the Fontan repair than those with mild PH [mean PAp < 45 mm Hg (n = 6; 17% vs. 100%; P = 0.008) or Rp < 4.5 Wood's unit/m(2) (n = 7; 20 vs. 86%; P = 0.045)]. Patients with PA banded after 6 months of age (n = 3) qualified less frequently for the Fontan operation than those banded before 6 months of age (n = 6; 0 vs. 83%; P = 0.048). These data suggest that ASD creation is an effective approach to qualify patients for the Fontan operation in the presence of restrictive left atrioventricular valve and interatrial obstruction, except those with longstanding severe PH following delayed PA banding.