[The technique of outflow tract reconstruction in patients with tetralogy of Fallot influence the morbidity 3 decades after repair]. / Die Technik der Ausflussbahnrekonstruktion bei Fallotscher Tetralogie beeinflusst die Morbidität der Patienten nach drei Jahrzehnte nach einer Korrekturoperation.

The purpose of this study was to examine long-term results of different surgical techniques in patients with tetralogy of Fallot considering their morbidity. We analyzed the data of 74 patients 24.5 +/- 3 years after surgical repair in childhood to evaluate their clinical status, maximal exercise capacity, medication and frequency of reoperations. We compared two groups of patients according to the surgical techniques employed: 1) TAP group (Trans anular Patch, n = 41) in which ventricular septal defects were closed with a Dacron patch, the right ventricular outflow was reconstructed by resection of the partial extension of the infundibular septum and transanular patch repair was performed because of hypoplastic pulmonary valve. 2) nonTAP group (33) in which no transanular patch repair was necessary. Most of the patients described their health as "good". 94% of the nonTAP group and 71% of TAP group were in NYHA class I. The rest were in NYHA class II. Despite the good clinical classification we found a reduced cardiopulmonary exercise capacity in all patients. More than 50% in the TAP group took medicine because of congestive heart failure and/or arrhythmia, which was present 3-times more often compared with the nonTAP group. Furthermore, 50% of TAP group patients had at least one reoperation during the follow- up: by comparison 5-times more often than the nonTAP group. These data show that the long-term outcome and morbidity of the patients after repair is closely related to the type of the surgical technique employed.

[Morphological and functional MRI studies after correction of aortic isthmus stenosis]. / Wertigkeit morphologischer und funktioneller Untersuchungen mit der MR-Tomographie nach Aortenisthmusstenosenkorrektur.

PURPOSE: To compare the results of different methods for postoperative assessment after coarctation repair by magnetic resonance imaging and to evaluate their reliability. The morphometric results are contrasted to functional parameters of CW Doppler, oscillometric pressure gradient and flow quantification in VEC-MRI. METHODS: 54 patients (age: 6 to 36 years) were assessed by MRI 3 to 31 years after coarctation repair. The aortic diameters were compared to growth-dependent normal values and to the diameter of the ascending (AA) and descending aorta (DA), and their mean values (MV). RESULTS: Patients after coarctation repair had mostly subnormal diameters of AA (mean value: 80% of normal) and AD (95% of normal). Compared to the control group, mean dispersion of AD diameters was significantly larger in the patient group (2.6 vs. 1.5 mm, p < 0.001). Degree of stenosis varied with the method. It was similar when using normal values and the diameter for DA, but dispersion was smaller when normal values were used. Correlation of the functional parameter to the degree of stenosis was weak. The highest correlation (r = 0.78) was reached when using normal values as the reference with mean cross-sectional velocity from VEC-MRI. CONCLUSION: The use of normal values as the reference for quantification of residual coarctation is more reliable than common methods. Since only one measurement is needed, it seems to be less susceptible to errors and more practical. MRI offers not only a tool for accurate morphologic assessment, but with VEC-MRI it is also possible to obtain a functional parameter which is superior to oscillometric pressure gradient and CW Doppler.

The pathogenesis of heart failure in infants with congenital heart disease.

BACKGROUND: The clinical symptoms of heart failure in infants with left-to-right shunts are thought to be explained by well-known hemodynamic disturbances such as pulmonary hypertension and overcirculation, but previous studies have not, thus far, found the expected correlations with hemodynamic and clinical parameters. Based on the neurohormonal model of heart failure, we hypothesised that the clinical symptoms of infants with left-to-right shunts are also related to neurohormonal disorders. METHODS: We compared various neurohormonal and hemodynamic parameters measured invasively in 70 infants with left-to-right shunts to the respiratory rate and gain in weight over a corresponding period of time. Heart rate correlated significantly with respiratory rate (r = 0.62***, p < 0.001) and gain in weight (r = -0.31*, p = 0.015), but more conventional measures of severity, such as the ratio of pulmonary to systemic flows, failed to show comparable correlations with clinical symptoms. Respiratory rate was related to levels of norepinephrine (r = 0.47***, p < 0.001) and plasma renin activity (r = 0.65***, p < 0.001). The important impact of autonomic imbalance on respiratory rate was underlined by an analysis of variability of heart rate in 26 infants that showed significantly reduced values for the domains of time and frequency. We were not able to find a conclusive multiple regression model with which to explain the symptom "failure to thrive". CONCLUSIONS: A increased heart rate, reduced variability in heart rate, and elevated levels of norepinephrine and renin are significant predictors of clinical symptoms such as tachypnea in infants with congenital cardiac malformations. The neurohormonal hypothesis, in which heart failure is interpreted not only as a hemodynamic derangement but also as a neurohormonal disorder, may be valid for infants with congenital cardiac malformations.

Endogenous nitric oxide and soluble tumor necrosis factor receptor levels are enhanced in infants with congenital heart disease.

OBJECTIVE: This study was designed to investigate cytokine and nitric oxide levels in pediatric patients suffering from chronic heart failure and to investigate effects of beta-blocker treatment on these levels. PATIENTS: Fifteen infants with heart failure resulting from left-to-right shunts with pulmonary overcirculation were compared with 11 infants with cyanotic heart defects with reduced pulmonary blood flow. Four of these patients were finally treated with the beta-blocker propranolol. MEASUREMENTS: Endogenous nitric oxide production was determined by measuring total plasma nitrite/nitrate (Griess method), and levels of soluble tumor necrosis factor receptors type 1 and type 2 (TNF-R1 and TNF-R2, respectively) were measured by commercially available enzyme-linked immunosorbent assay. MAIN RESULTS: In infants with left-to-right shunts, soluble tumor necrosis factor receptor levels were significantly elevated as compared with infants with cyanosis (TNF-R1: 1.7 +/- 0.5 vs. 0.8 +/- 0.3 ng/mL; p =.0003; TNF-R2: 8.1 +/- 4.0 vs. 5.1 +/- 3.2 ng/mL; p =.049). In addition, we found a significant correlation between nitrate/nitrite levels and TNF-R1 (r =.70; p =.0001) or TNF-R2 (r =.62; p =.0013), respectively. Furthermore, the tumor necrosis factor receptor levels in four children after beta-blocker treatment were lower as compared with levels before beta-blocker treatment. CONCLUSIONS: Immune mechanisms, such as cytokine or nitric oxide production, may be involved in pathogenesis of heart failure in children, and may contribute to the beneficial effects of beta-blocker treatment observed in these patients.

Propranolol treatment of congestive heart failure in infants with congenital heart disease: The CHF-PRO-INFANT Trial. Congestive heart failure in infants treated with propanol.

AIM: Infants with congenital heart disease and left-to-right shunts may develop significant clinical symptoms of congestive heart failure in spite of therapy with digoxin and diuretics. We investigated the effects of beta-blockade in infants with severe heart failure. METHODS AND RESULTS: We performed a prospective, randomized, open monocenter trial in infants treated with digoxin and diuretics (n=10) in comparison to 10 infants receiving additional beta-blocker therapy. After 17 days on average beta-blocker treated infants (propranolol:1,6 mg/kg/day) improved significantly with respect to Ross heart failure score (3.3+/-2.3 vs. 8.3+/-1.9, P=0.002), lower renin levels (338+/-236 vs. 704+/-490 microU/l, P=0.008) and lower mean heart rates in Holter ECG (118+/-10 vs. 142+/-11 beats/min, P<0.001). While digoxin and diuretic treated infants had unchanged mean heart rate (149+/-8 vs. 148+/-10 beats/min), less decrease of symptoms (Ross Score: 8.5+/-1.7 vs. 6.8+/-2.3, P=0.02) but a significant increase of renin levels (139+/-102 vs. 938+/-607 microU/l, P=0.001). CONCLUSION: Additional propranolol treatment but not digoxin and diuretics alone can effectively reduce clinical symptoms of heart failure in infants with congenital heart disease, who suffer from increased neurohormonal activation.

Activity of the renin-angiotensin-aldosterone and sympathetic nervous system and their relation to hemodynamic and clinical abnormalities in infants with left-to-right shunts.

We studied neurohormonal, clinical and invasively measured hemodynamic data of 47 infants with left-to-right shunts and varying degrees of congestive failure. When referred to a clinical heart failure score, plasma renin activities (r=0.71) and norepinephrine levels (r=0.43) are significantly increased. Arterial hypotension seems to be the hemodynamic trigger of renin release (r=-0.72), but not decreased systemic cardiac index (r=-0.43), the magnitude of the left-to-right shunt (r=0.33) or a reduced ejection fraction (r=0.12). These data indicate neurohormonal activation in infants with left-to-right shunts with preserved myocardial function is similar to the activation in adults with heart failure secondary to myocardial pump failure. These findings have to be considered for optimal medical treatment of these infants with angiotensin-converting enzyme inhibitors or beta-blockers.

[Electrocardiographic signs of autonomic imbalance in infants with congenital heart defects]. / Elektrokardiographische Zeichen der autonomen Imbalance bei Säuglingen mit angeborenen Herzfehlern.

Infants with congenital heart disease (CHD) and heart failure have elevated plasma norepinephrine levels (NE) as a sign for sympathetic activation. We analysed ECGs of 64 infants with CHD and found normal heart rates on average in four groups split up according to their NE. Mean heart rate in Holter ECGs was significantly reduced in infants with low NE (below 350 ng/l) but normal in the other groups (NE < 350 ng/l: 121 +/- 10/min; NE = 350-700 ng/l: 139 +/- 11/min; NE = 700-1300 ng/l: 142 +/- 13/min; NE > 1300 ng/l: 135 +/- 12/min). An analysis of heart rate variability in a subgroup of 25 infants showed significantly reduced values in patients with elevated NE in comparison to 70 healthy infants. Significantly reduced frequency domain measures in infants with elevated NE but also normal NE are evidence for a high diagnostic sensitivity of an analysis of heart rate variability for autonomic imbalance with sympathetic activation and parasympathetic withdrawal in infants with CHD.

Pathogenetic mechanisms of venous congestion after the Fontan procedure.

BACKGROUND: The hemodynamic status after a Fontan type procedure for definitive palliation of functionally univentricular hearts is dominated by a high central venous pressure, which seems to be one of several factors responsible for venous congestion appearing as a frequent complication in the early and late postoperative course. The purpose of our study was to find other hemodynamic parameters correlating with the presence of venous congestion and effusions in these patients. METHODS: We compared the hemodynamic data of 18 patients who had an uneventful long-term course after a Fontan type procedure with the respective data of 10 patients who developed symptoms of venous congestion in the immediate postoperative period. Based on a theoretical model, we developed an algorithm to calculate mean hydrostatic capillary pressure from mean arterial pressure, systemic vascular resistance index and central venous pressure. RESULTS: Pulmonary vascular resistance index (2.1 +/- 1.0 mmHg L-1 min m2), mean left atrial pressure (9.7+/-4.0 mmHg) and cardiac index (3.6+/-0.6 l/min/m2) are mainly normal in patients with venous congestion in the immediate postoperative period, but mean hydrostatic capillary pressure is significantly higher compared to patients without venous congestion (24.3+/-3.1 vs 18.3+/-4.0 mmHg). Lower mean hydrostatic capillary pressures in these patients are due to a highly significant increase of systemic vascular resistance index (18.6+/-4.2 versus 33.6+/-6.6 mmHg L-1 min m2) and a concomitant decrease of cardiac index to 2.4+/-0.3 l/min/m2. CONCLUSIONS: The increase of mean hydrostatic capillary pressure, caused by high central venous pressures but also by relatively low systemic vascular resistance indexes, seems to be the hemodynamic key parameter responsible for venous congestion and effusions in patients after a Fontan type procedure in the immediate postoperative period.

Anomalies of the abdominal aorta in Williams-Beuren syndrome--another cause of arterial hypertension.

UNLABELLED: Vascular disease in Williams-Beuren syndrome is based on an elastin arteriopathy which may cause stenoses in small and great vessels. This study presents the pattern of stenotic lesions of the abdominal aorta and the incidence of arterial hypertension. From 112 patients with Williams-Beuren syndrome followed since 1975, 25 patients were studied by aortography. The diameter of the thoracic aorta and the change in diameter to the iliac bifurcation were compared with normal data. Renal artery stenosis was suspected when the proximal vessel diameter was less than 50% of the distal diameter. Of the 25 patients, 20 had vascular stenosis of whom 19 patients were affected by segmental narrowing either of the thoracic aorta (n=9) or the abdominal aorta (n = 7) or both (n = 3). Hypoplasia of the abdominal aorta was characterised by the smallest diameters at the renal artery level and an increased diameter of the infrarenal abdominal aorta. A total of 11 patients had renal arterial stenosis, associated with narrowing of other aortic segments in 10 cases. Only one patient had a solitary stenosis of the renal artery. Arterial hypertension was diagnosed in 17 patients, 2 of them had no vascular lesions; in the remaining 15 patients stenosis was present in more than one segment (aorta 6, renal artery stenosis 1, both 8). CONCLUSION: Narrowing of the abdominal aorta in patients with Williams-Beuren syndrome is a frequent morphological manifestation of the arteriopathy. Isolated renal arterial stenosis was rare, since it was more frequently combined with a narrowed aorta. Hypertension is a common symptom in the affected group and must be regarded as a manifestation of generalised arteriopathy rather than renal hypoperfusion.

Effectiveness of low dose captopril versus propranolol therapy in infants with severe congestive failure due to left-to-right shunts.

UNLABELLED: To evaluate the therapeutical effects of the angiotensin converting enzyme inhibitor Captopril to the beta-blocker Propranolol in infants with congestive failure due to pulmonary overcirculation, we retrospectively analysed clinical, neurohormonal and hemodynamic data in 22 infants, 11 of whom were treated with Captopril (Group 1), 11 with Propranolol (Group 2). Age, weight, number of palliative operations, plasma renin activities and pulmonary to systemic flow ratios (3.5 vs. 3.5) were not significantly different prior to Captopril or Propranolol therapy. If treatment with digoxin and diuretics did not succeed, the infants were additionally treated with Captopril (1 mg/kg) for a mean of 7.4 months, or with 1.9 mg/kg Propranolol for 9.2 months. RESULTS: 1 mg/kg Captopril did not effectively suppress angiotensin converting enzyme in the steady state at trough level (92+/-52 vs. 87+/-50 nmol/min/ml). In the Propranolol group, the clinical heart failure score (2.6+/-1.5 vs. 7. 4+/-2.5) and plasma renin activities (14+/-10 vs. 101+/-70 ng/ml/h) were significantly lower, compared to the Captopril group. Length of hospital stay (23+/-9 vs. 52+/-24 days) was lower and weight gain (126+/-38 vs. 86+/-84 g/week) was higher within 3 months after starting Propranolol therapy. Significantly lower left atrial pressures (6.2+/-2.2 vs. 13.4+/-9.2 mmHg) and lower endiastolic ventricular pressures (7.6+/-2.5 vs. 12.6+/-4.0 mmHg) during pre-operative cardiac catheterization indicated a better diastolic ventricular function under chronic Propranolol treatment. CONCLUSION: Although high dose Captopril was not evaluated in this study, when compared to patients on low Captopril dosages, infants who received Propranolol treatment showed improvement in heart failure scores, shorter lengths of hospital stay, lower plasma renin activities and better diastolic ventricular functions.

[Circulatory failure in children with left-to-right shunt in the framework of congenital heart defects: pathophysiology and therapeutic results]. / Kreislaufinsuffizienz bei Kindern mit Links-rechts-Shunts im Rahmen angeborener Herzfehler--Pathophysiologie und therapeutische Konsequenzen.

In children with large left-to-right shunts secondary to congenital heart defects the imbalance between the pulmonary and systemic perfusion may lead to circulatory congestion with clinical signs similar to those of heart failure. The circulatory function in this state was evaluated by using the invasive measurements performed during cardiac catheterisations in n = 64 young patients with ventricular septal defect (n = 56) or complete atrioventricular septal defect (n = 8) aging 0.1-23.7 years (median 1.1 years). The mean shunt ratio was Qp/Qs = 2.4 (range 1-8). With increasing shunt ratio the pulmonary perfusion raised (r = 0.84), but the systemic output dropped significantly (r = -0.77) while the total cardiac output (Qp + Qs) increased slightly not exceeding 141/min/m2. In infants, the systemic hypoperfusion affects the hemoglobin content: Hb = 14.9-1.01 x Qs, r = 0.63, p < 0.01. This may be due to the diminished oxygen extraction reserve of 46%. With dropping systemic output, the vascular resistance increases and the mean aortic pressure (MAP) remains normal. The actual pressure values layed near to the curve of the normal aortic pressure calculated as MAP = Qs x Rs. This pressure-flow-resistance diagram was used to interpret the effects of vasodilators established by 7 studies: ACE-Inhibitors, Hydralazine, and Na-Nitroprusside reduce the vascular resistance effectively but induce hypotension, because the systemic output fails to increase. In the chronic circulatory congestion secondary to a large intracardiac left-to-right shunt the pulmonary perfusion increases with the shunt ratio but the systemic output decreases and the total cardiac output is limited to a maximum of 141/min/m2. In this state vasodilators cause systemic hypotension thus offering no acceptable therapeutic option.

[Noninvasive assessment of wall stress related velocity of circumferential fiber shortening as an index of left ventricular contractility in children]. / Nichtinvasive Bestimmung des Kontraktilitätsindex "wandspannungsbezogene zirkumferentielle Verkürzungsgeschwindigkeit des linken Ventrikels" bei Kindern.

Assessment of the myocardial contractility in terms of the velocity of circumferential fiber shortening appropriate to the actual left ventricular endsystolic wall stress requires endsystolic pressure measurement usually done invasively. But for noninvasive evaluation of this parameter, we elaborated an algorithm to derive the endsystolic pressure in the ascending aorta from oscillometric blood pressure measurements. In 99 infants, children, adolescents, and young adults (1 day-37 years, median 5.5 years) we performed direct pressure recordings in the ascending aorta while measuring the arterial blood pressure at the upper arm by the Dinamap 8100 Blood Pressure Monitor. If measured directly, endsystolic (ESP(direct)) and mean aortic pressure (MAP(direct)) correlated well: ESP(direct)) = 1, 04 * MAP(direct))-2.18; r(2) = 0.91; s(y.x.) = 5.1 mm Hg. Comparison between the endsystolic and the mean arterial pressure (MAP(Dinamap) resulted in: ESP(direct) = 1.19 * MAP(Dinamap)-4.8; r(2) = 0.74; s(y. x.) = 8.3 mm Hg. In 52 patients this equation was used to derive the endsystolic pressure from the mean arterial pressure. Then the endsystolic wall stress was determined using the calculated (ESSm(Dinamap)) as well as the directly measured endsystolic pressure (ESSm(direct)): mean difference (ESSm(Dinamap) - ESSm(direct)) = -2.1 kdyn/cm(2); 95% confidence limits: -16.2 to 12. 1 kdyn/cm(2); linear regression: ESSm(direct = 1.07 * ESSm(Dinamap) - 2.22; r(2) = 0.91; s(y.x.) = 7.1 kdyn/cm(2). In n = 12 infants with complex heart defects and severe congestive heart failure due to pulmonary hyperperfusion the contractility was monitored noninvasively to assess the effects of propranolol (1.5 to 2 mg/kg/day) given complementary to digoxin and diuretics. The advantage of noninvasive assessment of the contractility in clinical routine was confirmed by the result that long-term propranolol does not impair myocardial contractility in this setting.

Reduced frequency of occlusion of aorto-pulmonary shunts in infants receiving aspirin.

OBJECTIVE: Infants with severely reduced pulmonary perfusion due to complex congenital cardiac malformations are in need of an improved flow of blood to the lungs. One option for treatment is to construct a systemic-to-pulmonary arterial shunt. Although such shunts have been used since 1945, their spontaneous occlusion remains a major problem in the long-term. DESIGN: We studied all infants in whom a systemic-to-pulmonary arterial shunt had been constructed using a Gore-Tex tube graft between December 1989 and March 1996. PATIENTS: Of 46 infants undergoing construction of a shunt, 7 (15%) died within 30 days of surgery. The shunts had to be taken down in 2 infants. Thus, 37 infants were included in the study. All but three infants received Aspirin. Aspirin was discontinued on the personal decision of individual physicians. Of 22 infants, 3 never received Aspirin, and in 19 it was stopped well before undertaking subsequent surgery. Aspirin was administered continuously to 15 infants until further surgery. RESULTS: Those in whom Aspirin was discontinued, or not given, and those receiving Aspirin until further surgery, were comparable concerning their age, time of follow-up, severity of the cardiac lesions, and size and type of shunt. Partial or complete occlusion of the shunt occurred in 2 of 15 (13%) infants taking Aspirin, but was seen in 12 of 22 (54%) infants in whom Aspirin was discontinued. Of these, 3 died due to acute occlusion of the shunt. CONCLUSIONS: Aspirin reduced effectively the rate of occlusion of systemic-to-pulmonary arterial shunts, and should be continued as long as the shunt is in place.

Beta-blocker therapy of severe congestive heart failure in infants with left to right shunts.

We report on the clinical and neurohumoral effects of adding low-dose propranolol to conventional therapy with digoxin and diuretics in 6 infants with severe congestive heart failure due to large left-to-right shunts. A significant decrease in heart failure scores and a decrease of the highly activated renin-angiotensin-1 aldosterone system by approximately 70% strongly suggests a beneficial effect of this new therapeutic approach.

[Arterial hypertension and blood pressure profile in patients with Williams-Beuren syndrome]. / Arterielle Hypertension und Blutdruckprofil bei Patienten mit Williams-Beuren-Syndrom.

The prevalence of hypertension and the diurnal blood pressure pattern were investigated in patients with Williams-Beuren syndrome (WBS) by blood pressure measurements in 142 children, adolescents, and young adults (female n = 62, male n = 80; median age 6.5 years (0.1-34.3 years)) and evaluation of ambulatory blood pressure data from 45 patients (female n = 21, male n = 24; median age 7.8 years (1-23.8 years)). Measurements revealed systolic hypertension in 46.5% of 142 patients, diastolic hypertension occurred in 36.6% (i.e. actual pressure > 95 percentile). According to the ambulatory data 42.2% of 45 patients had hypertension (mean arterial pressure > normal + 2SD). The nocturnal decline of the blood pressure was normal in hypertensive patients but reduced in normotensives (p < 0.01 vs normals). Males were more often hypertensive than females (46% vs 38%). Hypertensives had a higher body mass index than normotensives (19.5 vs 16.6 kg/m2, p < 0.05). In normo- and hypertensive WBS patients mean heart rates were elevated during day- and nighttime (p < 0.02 vs normals) the latter due to a reduced nocturnal decline. The prevalence of hypertension in WBS patients amounts to about 40%, thus being four- to eight-fold in comparison to healthy young adults or children. The diurnal blood pressure pattern and the elevated heart rates indicate that an increased arterial stiffness due to the vascular disease in the WBS and augmented sympathetic activity might play a role in the genesis of hypertension. Thus, effective antihypertensive treatment is likely to become difficult. From our experience beta-blocking agents are often successful in hypertensive WBS patients.

[Cardiac output determination with transpulmonary thermodilution. An alternative to pulmonary catheterization?]. / HZV-Bestimmung mittels transpulmonaler Thermodilution. Eine Alternative zum Pulmonaliskatheter?

UNLABELLED: Cardiac output measurements are often helpful in the management of critically ill patients and high risk-patients. In this study an alternative technique for measurement of cardiac output by the transpulmonary indicator dilution technique (TPID) was evaluated in comparison to conventional thermodilution using a pulmonary artery catheter. With TPID, a thermistor-tipped catheter (the smallest available is 1.3 F) is placed in the aorta via a femoral artery introducer. Thus, TPID can also be used in very small children in whom placement of a pulmonary artery catheter may be difficult or even impossible. In principle, TPID is less invasive since the possible complications of the pulmonary catheters are avoided. We investigated the accuracy and reproducibility of transpulmonary thermodilution in patients over a broad range in age and body surface. METHODS: Following approval by the ethics committee and written consent, the data were obtained from 21 patients without a circulatory shunt undergoing diagnostic heart catheterization. The patients were between 0.5 and 25.2 years old, their body surface between 0.35 and 1.89 m2. Measurements were performed in duplicate with bolus injections of ice-cold normal saline (0.15 ml/kg), randomly spread over the respiratory cycle. In total 48 thermodilution curves were measured simultaneously in the pulmonary artery and in the aorta. Thermodilution curves were monoexponentially extrapolated for elimination of recirculation and cardiac output was calculated with a standard Stewart Hamilton procedure. RESULTS: The amplitude of the typical arterial thermodilution curve shows a smaller and more delayed course than the pulmonary artery thermodilution curve. There was a very good correlation between the values found by pulmonary and TPID cardiac output measurements (R = 0.968). There was a slightly smaller cardiac output value measured by the TPID (Bias = -4.7 +/- 1.5% sem) The reproducibility of duplicate measurements with the two methods were nearly the same, the standard deviation of the difference was 10.9% for the pulmonary thermodilution method and 11.7% for TPID. DISCUSSION. TPID gives an alternative technique for measurement of cardiac output. We showed over a broad range in age and body surface a very good correlation with thermodilution measurements in the pulmonary artery. The slightly smaller values for TPID are explained by early recirculation, for clinical purposes the difference is negligible. However, the reproducibility of a method is clinically very important. Both methods showed in duplicate measurements basically the same reproducibility. The disadvantage of TPID in being more sensitive to baseline alteration is counterbalanced by less respiratory variability in comparison to the conventional thermodilution technique. However, by increasing the amount of injected indicator (i.e., 0.2 ml/kg approximately equal to 15 ml in an adult) it is possible to reduce the effect of baseline alteration. By using fiberoptic catheters it is even possible to use TPID as double-indicator dilution technique to measure intrathoracic blood volume (ITBV) and extravascular lung water (EVLW). We conclude that in many patients TPID might be an attractive, less invasive and reliable alternative to conventional cardiac output measurement by pulmonary artery catheter.

[Effects of age in the correction of isthmus stenosis on postoperative stiffness of the aorta]. / Bedeutung des Alters bei Korrektur einer Isthmusstenose für die postoperative Steifheit der Aorta.

Operative surgery for coarctation aims to eliminate the narrowed segment of the aorta and to restore a normal function of the aortic Windkessel, which depends on normal elastic properties of the aorta. To evaluate the effect of age at coarctectomy on the postoperative aortic elasticity, parameters of regional wall stiffness within the aortic arch were determined in 24 children after coarctectomy by means of echocardiography and blood pressure measurements. Actual data were compared with reference data (mean value normalized to body weight: mn +/- SD) obtained from n = 43 children, adolescents and young adults (age 1 month to 28 years; mean 12.6 years): elastic modulus Epn = 0.20 +/- 0.07 Mdyn/cm2/kg0.11; stiffness index beta = 3.45 +/- 1.3; diameter Dn = 0.52 +/- 0.08 cm/kg0.37. The results revealed that 4.9 years (mean) after coarctation repair within the first year of life (mean 3.2 months, n = 10) the parameters of elasticity and the diameter did not differ from normal. In those n = 5 children operated on in the age of 4.7 years there was a tendency towards increased aortic stiffness and reduced diameter 8.9 years later. In n = 9 children with a mean age of 9.2 years at operation the elastic modulus was increased 7.6 years later: Epn = 0.28 +/- 0.11 Mdyn/cm2/kg0.11; (p < 0.01). The diameter of the proximal aortic arch was significantly reduced (DN =0.42 +/- 0.08 cm/kg0.37., P < 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)

Three decades of follow-up of aortic and pulmonary vascular lesions in the Williams-Beuren syndrome.

The diagnostic criteria of the Williams-Beuren syndrome (WBS) were established almost 3 decades ago. Until now there has been little knowledge about the natural and post-surgical history of vascular lesions in this syndrome. In order to evaluate the long term follow-up of aortic and pulmonary vascular lesions, we have analysed the catheterization data, angiocardiograms, and Doppler-echo measurements in 59 patients who were seen at least twice in our institution between 1961 and 1993. Their follow-up periods ranged from 2.1 to 28.2 years. Of 45 patients with supravalvular aortic stenosis (SVAS) with a mean follow-up period of 12.9 years, it became evident that pressure gradients of less than 20 mm Hg in infancy generally remained unchanged during the first two decades of life. Pressure gradients exceeding 20 mm Hg increased from an average of 35.5 mm Hg to 52.7 mm Hg in 13 patients. Of these, 8 required surgical relief of the narrowing. In 7 patients aortic hypoplasia was documented. In 5 of them the caliber of the aorta showed a tendency towards normalisation within a period of 11.9 to 23.9 years. Of 6 individuals with aortic hypoplasia and surgical relief of SVAS, 4 patients developed restenosis at the distal end of the aortoplasty patch. In contrast, 9 patients with operated SVAS-but without aortic hypoplasia-remained free of restenosis over a period of 11 years (mean). Coarctation occurred in 4/59 patients; restenosis was seen in 2 after 5 and 16 years. Peripheral pulmonary stenosis was followed in 23 patients over 14.4 years (mean).(ABSTRACT TRUNCATED AT 250 WORDS)

Effect of increased wall thickness on indices of left ventricular pump function in children.

OBJECTIVE: To investigate whether augmented chamber performance in children with a concentric hypertrophied left ventricle is due to increased myocardial shortening or a geometric effect of the thickened ventricular wall. DESIGN: Chamber performance in terms of fractional area change and myocardial shortening--that is, circumferential midwall shortening--were measured by cross sectional echocardiography in young people with normal left ventricles and those with concentric hypertrophy of the left ventricle. PATIENTS: 52 healthy infants, children, and young people (age range 3 1/2 weeks to 26 years; body weight 1.8-89 kg (mean 23.6 kg)) and 29 infants, children, and adolescents with ventricular hypertrophy (mean body weight 31.4 kg, age range 4 weeks to 18.7 years). MAIN OUTCOME MEASURES: Chamber areas, fractional area change, midwall circumferential shortening normalised to body weight. RESULTS: In the controls normalised reference values were: end diastolic cavity area, 1.47 (0.25) cm2/kg0.65; fractional area change, 0.56 (0.03); end diastolic myocardial area, 1.62 (0.25) cm2/kg0.55; midwall circumferential shortening, 0.21 (0.03). By comparison, the patients had normal chamber areas (end diastolic myocardial area, 1.57 (0.42) cm2/kg0.65), increased fractional area change, 0.68 (0.05) (P < 0.001), and normal midwall circumferential shortening, 0.21 (0.03). There was a significant relation between the degree of hypertrophy (in terms of end diastolic myocardial area) and pump function while midwall shortening remained constant: 0.08 x end diastolic myocardial area + 0.44 (r = 0.74, P < 0.001). CONCLUSIONS: The relation between myocardial shortening, wall thickness, and fractional area change emphasises that the augmentation of pump function variables in left ventricular hypertrophy in young people is an effect of the thickened wall and not necessarily due to increased myocardial shortening. This relation offers the possibility of assessing the adequacy of chamber performance with respect to the degree of hypertrophy.