Walter S. Culpepper

Cardiac Status in Juvenile Borderline Hypertension

A prospective M-mode echocardiographic study was done to look for early cardiovascular changes in children prone to hypertension with blood pressures between the 75th and 95th percentiles for age. Average systolic/diastolic pressures in 27 children with borderline hypertension were 137/89 mm Hg compared to 110/68 mm Hg for the 26 controls. Echocardiographic measurements were normalized for comparison using two methods. The borderline hypertensive group mean values were significantly greater than controls for left ventricular wall thickness (p less than 0.05 for method 1; p less than 0.001 for method 2), left ventricular mass (p less than 0.001; p less than 0.005) and left ventricular wall thickness to radius ratio (p less than 0.001, both methods). Echocardiographic estimates of left ventricular function were lower in the hypertensive group. This study suggests that cardiac hypertrophy can be shown by noninvasive means in some children before arterial pressure becomes elevated. To assess the incidence and possible consequences of early target organ changes, more extensive clinical evaluation of borderline hypertension in children is recommended.

Myocardial hypertrophy and ventricular performance in the absence of hypertension in spontaneously hypertensive rats.

Abstract Ventricular performance and myocardial hypertrophy were studied in maturing spontaneously hypertensive (SH) and normotensive Kyoto-Wistar (WKY) rats from 4 through 24 weeks of age. The development of hypertension in the SH rat was prevented by treatment of the newborn rat with nerve growth factor antiserum (NGFAS). NGFAS treatment had no effect on the blood pressure of WKY rats. The hearts of 1-day- and 2-week-old SH and WKY rats were also examined for evidence of hypertrophy. Cardiac indices of SH rats, regardless of NGFAS treatment, were similar to those of WKY rats until 12 weeks of age at which time they became significantly lower. Stroke indices of both SH groups were lower than those of the WKY groups at all ages studied. Heart rates, however, were significantly higher in the SH rats during the early hypertensive phase but later declined to control levels. NGFAS treatment, despite its effects on hypertension, did not prevent the development of myocardial hypertrophy. Left ventricular hypertrophy was found in SH rats from age 1 day to 24 weeks regardless of NGFAS treatment. In SH rats 1 day to 8 weeks of age right ventricualr hypertrophy was also noted. Thus myocardial hypertrophy is present in SH rats before or very early in the course of the development of hypertension and when hypertension is prevented by peripheral immunosympathectomy. These data support our earlier conclusion that the development of myocardial hypertrophy is independent of elevated blood pressure and suggest that myocardial hypertrophy may be a manifestation of an underlying myocardial abnormality which could account for the hemodynamic alterations found in SH rats.

Warfarin therapy initiated during pregnancy and phenotypic chondrodysplasia punctata.

An infant is described who has clinical manifestations and roentgenographic features consistent with the diagnosis of chondrodysplasia punctata. The mother of this infant received warfarin during pregnancy. Eight cases demonstrating an association between warfarin therapy during pregnancy and chondrodysplasia punctata in the child have been reported; in the present case therapy was initiated following conception (see following case report). Warfarin may be teratogenic, producing a phencopy of the heritable forms of chondrodysplasia punctata. Because of the evident association we suggest (1) warfarin is contraindicated in pregnancy and alternative anticoagulants should be used; (2) products of at-risk pregnancies should be screened for the characteristic radiologic findings; and (3) preconceptual counselling and antenatal diagnosis of the disease may be beneficial.

Pulmonary Artery Banding: Analysis of a 25-Year Experience

A 25-year experience (May 1962 through April 1987) with pulmonary artery banding in 183 patients was reviewed and analyzed. Pulmonary artery banding was performed in a heterogeneous group of patients aged two days to 60 months (median, 10 weeks; mean, 21.8 weeks) and weighing 1.4 to 13.8 kg (mean, 4.2 kg). Diagnosis was ventricular septal defect in 76 (41.5%) and atrioventricular communis in 41 (22.4%). Pulmonary artery banding was also used in patients with d-transposition of the great vessels with ventricular septal defect, double-outlet right ventricle, univentricular heart, tricuspid atresia, and truncus arteriosus. Early death occurred in 39 of 175 patients who underwent pulmonary artery banding at Ochsner Foundation Hospital (22.3%). Definitive operation has been performed in 37 of the patients who underwent pulmonary artery banding since 1979 with excellent outcome in 32 (86.5%). Pulmonary artery banding is a useful palliative procedure for a diverse group of patients with congenital cardiac anomalies and unrestricted pulmonary blood flow. With improved results of primary repair of intracardiac anomalies in small infants, however, pulmonary artery banding should be reserved for severely ill patients with complex lesions not amenable to early definitive correction. Currently, pulmonary artery banding is indicated in patients with excessive pulmonary blood flow and single ventricle or tricuspid atresia. Pulmonary artery banding is also appropriate in certain patients with atrioventricular communis and in patients with muscular or multiple ventricular septal defects. Pulmonary artery banding is an option in patients with ventricular septal defect and coarctation of the aorta.

Technique and Experience with Azygos Patch Modified Blalock-Taussig Anastomosis for Congenital Cyanotic Heart Disease

Seventeen patients 1 day to 28 months old with congenital cyanotic heart disease underwent a modification of the Blalock-Taussig shunt. Eight were newborn infants weighing 2.6 to 4.8 kg. All infants had complex congenital heart defects that were not considered amenable to early correction. There were no early deaths and no shunt failures. Postoperative complications were restricted to prolonged intubation in 2 patients and a subcutaneous wound infection in a 14-day-old infant. Follow-up from 1 to 31 months revealed minimal cyanosis, stable hemoglobin levels, and good shunt murmurs, and there have been no upper extremity complications. There were 2 late deaths; 1 (the oldest patient) was related to medication, and the second resulted from small bowel necrosis. The concept of the azygos vein patch modified Blalock-Taussig shunt involves two factors: (1) mobilizing as much length as possible of the subclavian artery in spite of its distal small size to allow for a tension-free shunt to prevent tension on the anastomosis as growth occurs, and (2) enlarging the subclavian artery distal to the vertebral artery origin with an autologous azygos patch. During performance of a standard Blalock-Taussig shunt, a longitudinal incision is made through the pulmonary artery across the anastomosis into the upper subclavian artery. The appropriate length of harvested azygos vein is used as a patch angioplasty across the shunt. A tension-free shunt with a patulous distal portion is achieved. Pulmonary overcirculation is avoided by the limiting size of the proximal subclavian artery. Temporary occlusion of the shunt at operation resulted in an increased mean blood pressure from 6 to 18% in all infants.(ABSTRACT TRUNCATED AT 250 WORDS)

Cardiovascular Responses to PEEP and CPAP Following Repair of Complicated Congenital Heart Defects

Fourteen infants and children ranging in age from 7 months to 8 years were studied in a hemodynamically stable condition following repair of various heart defects. Changes in cardiac index, stroke index, heart rate, systemic vascular resistance, mean arterial pressure, and central venous pressure were evaluated at levels of 0, 5, and 10 cm H2O using positive end-expiratory pressure (PEEP) in 14 patients and continuous positive airway pressure (CPAP) in 3 patients. No significant changes were found in any of the measurements taken at the different levels.

Simplified Technique for the Surgical Palliation of Pulmonary Atresia with Right Ventricular Hypoplasia and Intact Septum

A rapid, simple palliative technique for treatment of pulmonary atresia with a one-stage pulmonary valvotomy and central aortopulmonary artery shunt is described.

Iatrogenic Right Ventricular Failure in Tetralogy of Fallot Repairs: Reappraisal of a Distressing Problem

A patient with tetralogy of Fallot experienced isolated right ventricular failure when the right coronary artery was occluded by an encircling suture at the time of closure of the ventricular septal defect. Recognition and correction of the problem allowed weaning from cardiopulmonary bypass and an uneventful recovery. Because ventricular septal defects in tetralogy of Fallot are usually anterior and subaortic, injury to the right coronary artery, in close proximity to the superior aspect of the defect, is a potential danger. When isolated right ventricular failure occurs immediately after repair, suture occlusion of the right coronary artery should be considered as a possible cause.

198 IS MYOCARDIAL HYPERTROPHY IN HYPERTENSIVE CHILDREN RELATED TO BLOOD PRESSURE

The mechanism for the increase in left ventricular mass (LVM) in children with labile hypertension (HT) remains unresolved. M-mode echocardiograms (ME) were obtained from 27 HT children (mean age 14.4 y) and 26 normotensive (NT) children (mean age 14.1 y) of comparable sex, race and BSA. Mean systolic/diastolic blood pressure (SBP/DBP) in HT was 137/89; that in NT was 110/68 (p < 0.001). ME was digitized/analyzed with H-P computer, and the observed values expressed as SD from predicted normal (σ PN) based on age, BSA and HR. HT and NT values were similar for: LVEDD, LVEDD, LAmax, LVSV, Qlv, LVET and PEP/ET. However, HT values were greater than NT for: wall thickness (p < .001), LVM (p < .005), thickness/radius ratio (t/r) (p < .001), Ao (p < .05) and PEP (p < .025). HT values were lower than NT for %MAS (p < .01) and VCF (p < .05). Poor correlation was observed between SBP or DBP and LVM/M2 or O LVM (r = 0.34 to 0.43). Density function curves derived by multi-regression analysis (using equation: Ydv = K1 σPN1 + K2 σPN2 + Kn σPNn ± X, where Ydv = discriminating value and K, X = constants) and utilizing 11 echo parameters separated HT from NT with minimal overlap (p < .001). Moreover, positive correlation was observed between Ydv and resting DBP (r = 0.65), suggesting that the cardiac status of HT children may very well be related to the increased pressure overload of labile character and varying duration.

94 LEFT VENTRICULAR WALL STIFFNESS IN YOUNG SPONTANEOUSLY HYPERTENSIVE RATS

Eight week-old spontaneously hypertensive rats (SHR) and nor-motensive Kyoto-Wistar controls (WKY) were studied in order to determine the effect of hypertrophy on passive elastic left ventricular wall stiffness. After perfusion cooling and arrest, excised hearts were mounted on mitral and aortic cannulae and maintained in calcium-free Krebs solution (4°C). From multiple static pressure-volume cycles over a 0-10 mmHg pressure range, LV chamber distensibility (ΔV/ΔP) data were fitted to the equation P=A+Bexp[C(ΔV)]. Unstressed chamber volume (Vo) and LV mass (LVM) were then determined. Assuming a spherical geometry for the LV, elastic wall stiffness moduli, (Es) from linear elasticity theory and uniaxial stiffness (Us) on the basis of large deformation theory, were derived from the pressure volume data. At any given stress level, LV wall stiffness is greater in the young SHR than in WKY early in the development of myocardial hypertrophy and hypertension.