Drivers of aboveground wood production in a lowland tropical forest of West Africa: teasing apart the roles of tree density, tree diversity, soil phosphorus, and historical logging

Tropical forests currently play a key role in regulating the terrestrial carbon cycle and abating climate change by storing carbon in wood. However, there remains considerable uncertainty as to whether tropical forests will continue to act as carbon sinks in the face of increased pressure from expanding human activities. Consequently, understanding what drives productivity in tropical forests is critical. We used permanent forest plot data from the Gola Rainforest National Park (Sierra Leone) – one of the largest tracts of intact tropical moist forest in West Africa – to explore how (1) stand basal area and tree diversity, (2) past disturbance associated with past logging, and (3) underlying soil nutrient gradients interact to determine rates of aboveground wood production (AWP). We started by statistically modeling the diameter growth of individual trees and used these models to estimate AWP for 142 permanent forest plots. We then used structural equation modeling to explore the direct and indirect pathways which shape rates of AWP. Across the plot network, stand basal area emerged as the strongest determinant of AWP, with densely packed stands exhibiting the fastest rates of AWP. In addition to stand packing density, both tree diversity and soil phosphorus content were also positively related to productivity. By contrast, historical logging activities negatively impacted AWP through the removal of large trees, which contributed disproportionately to productivity. Understanding what determines variation in wood production across tropical forest landscapes requires accounting for multiple interacting drivers – with stand structure, tree diversity, and soil nutrients all playing a key role. Importantly, our results also indicate that logging activities can have a long‐lasting impact on a forest's ability to sequester and store carbon, emphasizing the importance of safeguarding old‐growth tropical forests.

Use of an airborne lidar system to model plant species composition and diversity of Mediterranean oak forests

Airborne lidar is a remote-sensing tool of increasing importance in ecological and conservation research due to its ability to characterize three-dimensional vegetation structure. If different aspects of plant species diversity and composition can be related to vegetation structure, landscape-level assessments of plant communities may be possible. We examined this possibility for Mediterranean oak forests in southern Portugal, which are rich in biological diversity but also threatened. We compared data from a discrete, first-and-last return lidar data set collected for 31 plots of cork oak (Quercus suber) and Algerian oak (Quercus canariensis) forest with field data to test whether lidar can be used to predict the vertical structure of vegetation, diversity of plant species, and community type. Lidar- and field-measured structural data were significantly correlated (up to r= 0.85). Diversity of forest species was significantly associated with lidar-measured vegetation height (R(2) = 0.50, p < 0.001). Clustering and ordination of the species data pointed to the presence of 2 main forest classes that could be discriminated with an accuracy of 89% on the basis of lidar data. Lidar can be applied widely for mapping of habitat and assessments of habitat condition (e.g., in support of the European Species and Habitats Directive [92/43/EEC]). However, particular attention needs to be paid to issues of survey design: density of lidar points and geospatial accuracy of ground-truthing and its timing relative to acquisition of lidar data.

Valvular hemodynamics and arrhythmias with exercise following the Ross procedure

Pulmonary autograft aortic valve replacement (Ross procedure) is increasing in popularity, particularly in children and young adults. We performed a controlled study of pediatric and adult Ross procedure patients to evaluate postoperative exercise valvular hemodynamics and cardiac rhythm. Thirty-one patients and 24 controls underwent stress echocardiography. Doppler and 2-dimensional echocardiography assessed valvular hemodynamics and right and left ventricular size at baseline and after exercise. Electrocardiography monitored cardiac rhythm. Patients and controls had neoaortic and neopulmonic valve insufficiency ranging from none to moderate that improved or did not change with exercise. Baseline and exercise mean peak transaortic gradients were not significantly different between patients (baseline 6.3 +/- 3.8 mm Hg, exercise 12.8 +/- 7.3 mm Hg) and controls (baseline 6.7 +/- 2.5 mm Hg, exercise 14.3 +/- 5.2 mm Hg). However, baseline and exercise mean peak transpulmonic gradients were significantly different between patients (baseline 20.7 +/- 9.6 mm Hg, exercise 45.2 +/- 23.5 mm Hg) and controls (baseline 3.7 +/- 1.3 mm Hg, exercise 10.6 +/- 3.7 mm Hg). Significant exercise-induced arrhythmias occurred in 8 patients (26%) and no controls. Occurrence of arrhythmias correlated with an older age at surgery and age at study. After the Ross procedure, patients have valve competence and transaortic gradients similar to controls at baseline and with exercise. However, patients have significantly increased baseline and exercise transpulmonic gradients compared with controls. Furthermore, exercise-induced arrhythmias occurred frequently in our patient group and were associated with an older age at surgery and age at study.

Effects of high-dose inhaled corticosteroids on bone metabolism in prepubertal children with asthma

We studied the effect of inhaled corticosteroids on the increase in bone mineral content in prepubertal children with asthma. Forty-eight asthmatic, prepubertal children receiving either inhaled beclomethasone dipropionate or budesonide were evaluated. Nine children of similar age not receiving inhaled steroids served as controls. The average age of corticosteroid-treated children was 7.8 +/- 2.4 years, and of control children, 8.4 +/- 2.1 years (NS). The average dose of inhaled corticosteroids in the treated children was 0.67 +/- 0.48 mg/m(2)/day, and they were followed over a 9-20-month period. Total bone mineral content (TBMC) was measured at baseline and after 9-20 months. A derived value for 12 months' TBMC was calculated, assuming that changes in TBMC were linear with the passage of time. The change in TBMC over a 12-month period was 264 +/- 68 mg for the corticosteroid-treated children and 330 +/- 84 mg for control children (P < 0.025). In a multiple regression analysis in which adjustments were made for the effects of age, height, and weight, the change in TBMC in corticosteroid-treated children was inversely related to the inhaled steroid dose/m(2)/day (P = 0.016). The increase in the lumbar vertebral bone mineral density in control children was also significantly greater than in the corticosteroid-treated children (P < 0.025). We conclude that inhaled steroids, at an average dose of 0.67 mg/m(2)/day, when used in the treatment of asthma reduce the acquisition of bone mineral in prepubertal children.

Quantitative digital angiography as an adjunct to the intraoperative placement of endovascular stents in congenital heart disease

Clearly identifiable intraoperative landmarks render the placement of intraoperative stents difficult. Preoperative use of quantitative digital angiography helps the surgeon accurately insert endovascular stents intraoperatively. By using defined points of reference, we were able to carefully select the size and lengths of stents before the operation and precisely place these stents in the operating room. Furthermore, we have been able to redilate these stents using the same techniques at subsequent operations. Our results reflect the efficacy of this technique.

Effects of doxorubicin on diastolic function, contractile reserve, and ventricular-vascular coupling in piglets

The use of doxorubicin as an anticancer drug is limited by its cardiac toxicity. To examine the adverse effects of doxorubicin on cardiac function and ventricular-vascular coupling in piglets, eight piglets received five doses of intravenous doxorubicin, 1.5 mg/kg/dose, every 4-7 days starting at 3 weeks of age. A control group consisted of eight normal piglets. Using conductance and manometric catheters, indices of cardiac function, including end systolic elastance (Ees), preload-recruitable stroke work, dP/dtmax, tau, dP/dtmin, dV/dtmax, and end systolic stiffness, were calculated from volume and pressure measurements at rest and during infusion of isoproterenol. Ventricular-vascular coupling was examined by measuring arterial elastance (Ea) and Ea/Ees. Significant differences in relaxation were found between groups. Indices of diastolic stiffness and of contractile function were not different between groups. Baseline contractile efficiency was increased in the doxorubicin group. Ea and Ea/Ees were lower in the doxorubicin group. Ea/Ees was near 1 at baseline in the doxorubicin group, indicating that conditions were optimized for performance of external stroke work. Therefore, the reserve to increase external cardiac work was diminished. The finding of altered diastolic function suggests the importance of screening of diastolic indices to detect the earliest disturbances in cardiac function caused by doxorubicin.

Treatment of acute asthma: salbutamol via jet nebuliser vs spacer and metered dose inhaler

OBJECTIVE

To compare the efficacy of salbutamol delivered by jet nebuliser (JN) with salbutamol via a pressurised metered dose inhaler (PMDI) and a large volume spacer (Volumatic) for management of acute asthma.

STUDY POPULATION

A total of 160 children aged from 4 to 12 years presenting to an Emergency Department with acute asthma.

METHODS

The study was of multicentre (n=5) randomised, double blind, parallel design. Children weighing less than 25 kg received salbutamol 2.5 mg via the JN or 600 microg (six puffs) from the PMDI. Children over 25 kg received salbutamol 5 mg via the JN or 1200 microg (12 puffs) via the PMDI. Clinical score (range 0-12) and PEF (over 7 years) were recorded at baseline and 15, 30, 45 and 60 mins post administration.

RESULTS

The improvement from baseline at 30 min in the clinical score was 1.87 for JN and 1.43 for PMDI (P=0.09) and at 60 min was 2.15 for JN and 1.12 for PMDI (P=0.0001). The improvement in PEF at 30 min was 51 L min(-1) for JN and 27 L min(-1) for PMDI (P=0.0007) and at 60 min was 57 L min(-1) for JN and 31.5 L min(-1) for PMDI (P=0.001).

CONCLUSION

Administration of salbutamol via a PMDI and a large volume spacer device provides effective relief in the management of acute asthma in children, but to a lesser extent than a jet nebuliser. This difference may represent a dose response effect.

Oral fluid therapy. A promising treatment for vasodepressor syncope

OBJECTIVE

To investigate the predictive value of an intravenous fluid bolus during tilt table testing on clinical outcome and to evaluate of oral therapy is an effective treatment for patients with vasodepressor syncope.

DESIGN

Retrospective cohort.

SETTING

Regional pediatric cardiology outpatient clinic.

PATIENTS

Patients (N = 58) with a positive baseline tilt table testing result who were treated with oral fluid therapy between February 1991 and March 1996.

INTERVENTIONS AND MAIN OUTCOME MEASURES

Patients with a positive tilt table test result were given an intravenous bolus of isotonic saline solution. Responders were identified as having a negative tilt table test result after the bolus. Patients were prescribed a protocol of oral fluid therapy. Data were obtained from the medical record and a mailed survey.

RESULTS

Of the 58 subjects, 90% had no recurrent syncope while receiving oral fluid therapy. During tilt table testing, the mean decrease in mean arterial pressure seen with symptomatic events was lower after the intravenous fluid. The heart rate, which dropped during the initial test, increased during the rests after the intravenous bolus. In the nonresponders, symptomatic episodes occurred significantly later in the tilt table test when given fluids. The response to intravenous fluid bolus had positive predictive value of 92% and negative predictive value of 11% of clinical outcome.

CONCLUSIONS

Our data suggest that oral fluid therapy is an effective treatment for vasodepressor syncope in our population. Fluid bolus response during tilt table testing has a high positive but a low negative predictive value of response to oral fluid therapy. We now recommend oral fluid therapy as a primary intervention and reserve tilt table testing for oral fluid therapy failures.

Reopening after successful coil occlusion for patent ductus arteriosus

OBJECTIVES

This study was performed to determine the frequency of patent ductus arteriosus (PDA) reopening and the factors that may predict reopening after successful coil occlusion.

BACKGROUND

Transcatheter coil occlusion is a widely used and accepted method to close a PDA. After documented successful coil occlusion, we found PDAs that reopened. We hypothesized that specific factors are involved in those that reopened.

METHODS

All patients who underwent percutaneous transarterial PDA coil occlusion were studied. Successful coil occlusion was documented. PDA reopening was determined when Doppler-echocardiography (DE) performed after the procedure was negative for PDA flow but at follow-up demonstrated PDA shunting. Patients with a reopened PDA were compared with all other patients in evaluating independent variables.

RESULTS

Coil occlusion for PDA was attempted in 22 patients. Clinical success was achieved in 20 patients (91%), and DE was negative for PDA shunting in 19 patients (90%). At follow-up, five patients demonstrated reopening. The PDA minimal diameter was 1.4 +/- 0.5 mm (mean +/- SD) for the reopened group and 1.2 +/- 0.7 mm for the other patients. The PDA length was 2.9 +/- 1.9 mm for the reopened group and 7.1 +/- 3.2 mm for all other patients. All those with type B PDA were in the reopened group. When independent variables were compared between groups, only PDA length and type B PDA predicted reopening (p < 0.05).

CONCLUSIONS

PDA reopening may occur after successful coil occlusion. Short PDA length and type B PDA are associated with reopening. The data suggest that in such anatomy, alternative strategies to the current coil occlusion technique should be considered.

Left ventricular systolic function, arterial elastance, and ventricular-vascular coupling: a developmental study in piglets

Circulatory changes occur during perinatal life that increase cardiac output and left ventricular contractile reserve. To examine postnatal changes in left ventricular systolic function and ventricular-vascular coupling, piglets underwent cardiac catheterization at 1, 2, 4, and 6 wk of age. We measured end-systolic elastance (Ees), preload-recruitable stroke work, dP/dt(max), the dP/dt(max) end-diastolic volume relation, cardiac index, heart rate, arterial elastance (Ea), and the ratio Ea/Ees, at rest, during isoproterenol infusions (0.05-1.0 microg/kg/min), and after propranolol (1 mg/kg i.v.). Resting heart rate and cardiac index decreased between 1 and 6 wk. In 1 wk olds, resting Ees was at maximum and was unchanged during isoproterenol infusion; isoproterenol increased other contractility indices. Two, 4, and 6 wk olds demonstrated reserve using all contractility indices. Contractile efficiency was not different between ages. In 1 wk olds, Ea decreased during isoproterenol infusion; isoproterenol did not change Ea at 6 wk. Ea/Ees was higher at rest at 6 wk than at 1 wk, and fell significantly on isoproterenol; isoproterenol did not change Ea/Ees at 1 wk. With beta-adrenergic stimulation, 1 wk olds increased cardiac index by increasing heart rate and decreasing afterload, 6 wk olds increased cardiac index by increasing heart rate and contractility; no change in contractile efficiency was found in either group. In summary, contractile reserve is limited at 1 wk when measured by Ees, but other indices demonstrated reserve. Indexed Ea falls in response to beta-adrenergic stimulation in all ages but 6 wk. Ventricular-vascular coupling is optimized at 1 wk even under baseline conditions.

Prominent venous valves in hypoplastic right hearts

To investigate the hypothesis that embryologic abnormalities in the venous valves may be associated with abnormal cardiac development, we examined the right atrial morphologic characteristics in 20 hearts with underdevelopment of the right heart and 17 normal hearts. In the study group, 16 (80%) of the patients had significantly enlarged eustachian valves, one (5%) was slightly enlarged, and three (15%) were smaller than expected. Five (25%) had cor triatriatum dexter. In comparison, eustachian valves in the control specimens were prominent in only one (6%), normal in five (29%), and almost absent in eight (47%). The thebesian valve was also more prominent in the study cohort when compared with controls (p < 0.05). No other morphologic features of the right atrium analyzed in this study differed from those found in normal specimens. We speculate that failure of the venous valves to regress appropriately may create abnormalities in fetal circulation that predispose the fetus to maldevelopment of the right heart structures.

Digital acoustic analysis of precordial innocent versus ventricular septal defect murmurs in children

This study examines whether digital acoustic analysis of individual cardiac sound components for intensity, timing, and frequency could differentiate between innocent and pathologic murmurs. With use of this new technology, sensitive and specific criteria can be established for a fast and easy screening procedure to help differentiate between innocent and ventricular septal defect murmurs in children with suspected heart disease.

Natural course of isolated pulmonary valve stenosis in infants and children utilizing Doppler echocardiography

Most natural history data regarding pulmonary stenosis (PS) were obtained from cardiac catheterization studies over 15 to 20 years ago. Selection bias in these studies often excluded patients with mild disease and infants. Today, Doppler echocardiography allows accurate serial assessments of stenotic lesions in patients of all ages. This study evaluates the natural history of PS utilizing serial Doppler examinations in the pediatric population. A total of 147 patients with PS and serial echocardiographic data were identified. Age at initial echocardiogram ranged from 2 days to 15 years, with a mean follow-up of 2.4 years. Sixteen of 56 patients (29%) initially evaluated within 1 month had a > or = 20 mm Hg increase in their peak systolic pressure gradient. Only 7 of 89 patients (8%) initially evaluated over 1 month had a > or = 20 mm Hg increase. Eleven of 40 newborn infants (28%) with mild obstruction had progression to moderate or severe PS compared with 10 of 68 patients (15%) initially evaluated over 1 month. Moderate PS in the newborn was also more likely to progress compared with older children. Of the 16 newborns with > or = 20 mm Hg increases, 8 developed the increase in < or = 6 months. In contrast, no patient aged >2 years whose initial gradient was <50 mm Hg developed severe PS. Mild PS may not be static, particularly in young infants. Progression in this age group occurs more often and more rapidly than in older infants and children.

Effects of commonly used adrenergic agonists on left ventricular function and systemic vascular resistance in young piglets

This study compared the effects of high-dose infusions of various adrenergic agonists on cardiovascular function in piglets. We hypothesized that agonists would have different effects on systolic, diastolic, and vascular functions. Nine anesthetized 3-week-old piglets underwent cardiac catheterization. Manometric and conductance catheters measured pressures and volumes. Data were acquired at rest and during infusions of epinephrine, norepinephrine, dopamine, dobutamine, isoproterenol, and phenylephrine. End-systolic elastance, preload-recruitable stroke work, cardiac output, the maximum and minimum derivatives of left ventricular pressure, the relaxation constant tau, peak filling rate, and end-diastolic stiffness were obtained. Contractile efficiency and the cardiac output/pressure-volume area ratio were calculated. Regression was used for analysis of variance; p < 0.05 was considered significant. All agonists increased indexes of contractility. beta-Adrenergic agonists enhanced relaxation. Isoproterenol and dopamine increased efficiency. No drug changed diastolic stiffness. Therefore both alpha-adrenergic and beta-adrenergic agonists have inotropic effects in the 3-week-old piglet. Some beneficial effects of beta-agonists on cardiac output may be due to enhancement of relaxation and to afterload reduction. Various agents exert different effects on the cardiovascular system, and these differences may be clinically important.

New developments in the treatment of hypoplastic left heart syndrome

Progress has been made in the treatment of children born with hypoplastic left heart syndrome. From a mortality of more than 95% at 1 month of age in an era prior to surgical intervention, an actuarial survival of 58% at 5 years of age for staged surgical palliation is now being achieved. The short-term results with cardiac transplantation also appear to be excellent. Efforts are being directed at identifying potential risk factors, and fetal ultrasonography is capable of monitoring the progression of this malformation in utero. Refinements in surgical technique and postoperative care have been achieved, reducing the overall risk of the Norwood operation and sudden hemodynamic instability in the intensive care unit. Practice patterns and perceptions of outcome vary widely. Presently there is no unanimity of opinion that surgical therapy should be offered to all patients, and comfort care continues to be a family option.

Serum lidocaine concentrations after subcutaneous administration in patients undergoing cardiac catheterization in a pediatric institution

OBJECTIVE

We wished to determine serum lidocaine concentrations after subcutaneous injection during cardiac catheterization.

METHOD

Serum lidocaine concentrations were measured in 50 patients during catheterization.

RESULTS

Serum concentration was linearly related to dose per kilogram of body weight. Lidocaine concentrations were therapeutic in 38% of patients.

CONCLUSION

Lidocaine dose must be considered when the drug is used for local anesthesia in children.

Population requirements for capitation planning in pediatric cardiac surgery

OBJECTIVE

To determine the population number necessary to generate a sufficient volume of pediatric cardiac surgeries to allow accurate prediction of resource utilization.

DESIGN

All pediatric cardiac surgical patients receive care in our institution by means of only four clinical pathways that are based on acuity, not diagnosis or procedure. This allows accurate tracking of resource utilization. Based on available information, 750 consecutive surgically treated patients were retrospectively assigned to a pathway. They were subsequently subdivided into study groups of decreasing sizes from 150 to 35. Variability of pathway distribution from group to group was examined as a measure of the ability to predict resource utilization based on group size. Pediatric cardiac statistics from the state of Ohio were then used to extrapolate to the population base necessary to generate each group size.

SETTING

A regional pediatric cardiac referral center.

PATIENTS

All sequential patients who underwent pediatric cardiac surgery between July 1991 and January 1994.

RESULTS

Statewide statistics showed that a population base of 1 million people generates 100 pediatric cardiac operations. Groups of 100 patients or greater had minimal variation in pathway distribution from group to group, allowing accurate prediction of hospital charges. This was not true for groups of 50 patients or less.

CONCLUSIONS

Resource utilization for pediatric cardiac surgery can be accurately predicted in a capitated setting for populations of 1 million covered lives (100 procedures) or greater. For populations of 500 000 covered lives or less, variability of case mix is great enough to suggest the need for a more individualized payment mechanism.

Anomalous course of the left main coronary artery in tetralogy of Fallot

An extremely rare coronary artery anomaly where the left main coronary artery arose anteriorly from the right coronary sinus and coursed in front of the right ventricular outflow tract was present in a patient with tetralogy of Fallot. Preoperative angiocardiography was interpreted as normal. Operative recognition was prevented by dense adhesions and a partial intramural course. Division of the vessel at repair resulted in death of the patient. The angiographic pattern associated with this anomaly is very unusual, and in many views looks deceptively normal. Details are presented.

Standardizing care delivery for infants and children with common congenital cardiac lesions

The emergence of managed care is influencing the practices of pediatric cardiology and cardiac surgery. The need for efficiencies brought about by standardizing care whenever possible has led to the development of care guidelines and clinical pathways. Care guidelines are general algorithms mapping the care of a specific problem. They are patient oriented and cover all aspects of care from diagnosis onward. National task forces have recently published guidelines for the care of children with specific congenital cardiac defects, and some of these are reviewed. Clinical pathways are more specific to an episode of inpatient or outpatient care. They consist of expected defined outcomes of care, including all tests, monitoring, and intervention. In other fields, clinical pathways have been developed for specific diagnoses or procedures. However, in pediatric cardiac surgery, the variety of conditions and operations is so great that two different methods of acuity-based, rather than disease-based, clinical pathway methodologies were developed that have been shown to decrease lengths of stay and hospital charges. Refinement of the system will require more sophisticated data, including the delineation of actual costs rather than charges, along with refinement and standardization of outcomes measurements. With fundamental changes in the delivery system, the roles of the specialist and the primary care physician have undergone changes that will continue to evolve. Vigilance on the part of all providers will be necessary to assure quality of care in this new milieu.

Hypoplasia of the eustachian valve and abnormal orientation of the limbus of the foramen ovale in hypoplastic left heart syndrome

We examined the eustachian valve and the limbus of the foramen ovale in 42 hearts with hypoplastic left heart syndrome (HLHS) and in 16 normal hearts. In HLHS, only 4.8% of the eustachian valves were moderately to well developed, whereas the remaining 95.2% were abnormal (p < 0.001): 92.9% of the eustachian valves were absent or markedly hypoplastic, and 2.4% had an abnormally redundant and enlarged eustachian valve. The eustachian valve was well developed in 87.5% of normal hearts. In addition, the lesser development of the eustachian valve seemed to correlate with lesser development of the left side of the heart. The limbus was well developed in 100% of the normal hearts and moderately to well developed in only 33.3% of the HLHS group (p < 0.001). Most hearts in the HLHS group had marked hypoplasia of the limbus, which was rotated and deviated so as to be close to the superior vena caval entrance.

Clinical pathways can be based on acuity, not diagnosis

The standardization of medical practice is gaining acceptance as a technique for controlling length of stay and hospital charges, while maintaining quality. Most clinical pathways address specific diagnoses or procedures, but we have developed a new approach in which pathways for cardiac care are based on acuity. All congenital cardiac surgical care rendered at Columbus Children's Hospital now falls within one of four such clinical pathways. This simplified approach is easy to use and has been well accepted. Our experience in a group of 107 consecutive patients treated in this fashion is described. The results of variance analyses, along with length of stay and charge data, are presented to demonstrate the degree to which resource utilization can be standardized in this widely variable group of patients whose problems were made cohesive by classification according to acuity level. We conclude that the resultant standardization offers considerable advantages for the managed care environment.

The cost of congenital heart disease in children and adults. A model for multicenter assessment of price and practice variation

OBJECTIVE

To assess the cost of congenital heart disease (CHD) and to assess whether practice pattern or price was more responsible for variation. RESEARCH DESIGN AND SETTING: Data were collected from Charleston, NC; Columbus, Ohio; Detroit, Mich; Houston, Tex; Los Angeles, Calif; and New York, NY. The CHD was first classified as to physiologic characteristics and severity. For each type of CHD, the number of clinic visits, hospitalizations, and years of medication use were estimated.

RESULTS

On the basis of actual charges, the "prices" were calculated as follows, in 1992 dollars: for patients from birth to 21 years: benign disease (19% of patients), $3940; acyanotic disease (45%), $49,730; cyanotic disease (36%), $102,084; and average for all CHD categories, $59,877; for patients 22 to 40 years of age (of whom 24% had resolved defects or were dead): benign disease (19%), $3470; acyanotic disease (52%), $12,981; cyanotic disease (29%), $39,187; and average for all CHD, $18,773. The cost for the group from birth to 21 years varied from $47,500 to $73,600, accounting for 55% by practice (number of echocardiograms and cardiac catheterizations) and 45% by price, although mortality was similar.

CONCLUSIONS

The treatment of CHD is comparatively inexpensive, especially in adult survivors. The variation in both practice and price bears further study, with comparison to determine the most cost-effective strategies for treating these patients.

Coronary artery fistula in the pediatric age group: a 19-year institutional experience

Ten patients with coronary artery fistulae were identified from records at Columbus Children's Hospital between 1974 and 1993. Clinical presentations of patients were quite variable, from 1 day to 20 years of age. Symptoms ranged from none to severe cardiorespiratory failure requiring extracorporeal membrane oxygenation. Long term follow-up revealed one sudden death and one spontaneous closure of the fistula. This lesion should be ruled out in patients who present as extracorporeal membrane oxygenation candidates. Patients with mild forms of this lesion may be followed up medically if the left to right shunt is inconsequential, because spontaneous closure is a possibility. Because of the risk of sudden death, close long-term follow-up is mandatory even for operated patients, and antiplatelet therapy should be considered for these patients.

Intraosseous adenosine. As effective as peripheral or central venous administration?

OBJECTIVE

The purpose of this study was to determine if intraosseous administration of adenosine is effective and, if so, to establish therapeutic dosage criteria for the intraosseous route compared with peripheral or central intraosseous route compared with peripheral or central venous routes.

RESEARCH DESIGN

Randomized, unblinded, cross-over, within-animal control study.

SETTING

University hospital in Ohio.

SUBJECTS

Thirty newly weaned piglets.

SELECTION PROCEDURE

Consecutive sample.

INTERVENTIONS

Thirty newly weaned pigs were transesophageally (n = 26) or transvenously (n = 4) paced at a cycle length that was 10% longer than the Wenckebach threshold. The minimum effective dose of adenosine necessary to induce atrioventricular block during pacing was recorded for peripheral venous, central venous, and intraosseous routes.

MEASUREMENTS AND RESULTS

The baseline resting heart rate and Wenckebach thresholds were not statistically different between subjects or between different routes of administration. The intraosseous route required a minimum effective dose of 127 micrograms/kg. Using a log transformation, the difference between central venous and peripheral venous doses was found to be statistically significant. The intraosseous dose was not statistically different from the central venous or peripheral venous doses.

CONCLUSION

The intraosseous route is an effective way of administering adenosine. The peripheral venous dose required to achieve atrioventricular block is higher than the central venous dose and the intraosseous dose is intermediary to the central venous and peripheral venous doses.

Cavopulmonary anastomotic aneurysm: a complication in pulsatile pulmonary arteries

An aneurysm of a left superior vena cava developed after anastomosis to the left pulmonary artery during repair of an atrioventricular septal defect with a persistent left superior vena cava entering directly into the left atrium. We believe this implies caution should be used in accepting the recent suggestion of using a bidirectional cavopulmonary connection to a pulsatile pulmonary arterial circuit as a way of allowing anatomic correction of atrioventricular septal defect with a small right ventricle.

Use of cardiac catheterization in pediatric cardiac surgical decisions

Current practice patterns relating to pediatric cardiac catheterization (Cath) have considerable economic implications. The decreased cost and risk of noninvasive methods such as echocardiography (ECHO) and magnetic resonance imaging (MRI) make them attractive alternative diagnostic methods if they can sufficiently define cardiac anatomy and the need for surgical intervention. We reviewed a recent cardiac surgical series of 465 cases in 1.5 years to determine how often a Cath was performed prior to surgery. Overall, 59.4% of the procedures were preceded by a Cath (76% of open heart operations, and 26.7% of closed heart operations). We specify the situations where we feel enough information is available for preoperative decision making from non-invasive testing, and we present some diagnostic pitfalls that have been encountered.

Cardiovascular health and disease in children: current status. A Special Writing Group from the Task Force on Children and Youth, American Heart Association

More than 600,000 children in the United States have a congenital or acquired cardiac abnormality, and millions more are at risk of developing atherosclerotic disease in adulthood, a risk made particularly evident by the prevalence of cardiovascular risk factors in the young. There are barriers to optimum prevention and treatment of these conditions in children and youth. The AHA's Task Force on Children and Youth has described these barriers and outlined a series of recommendations and strategies to meet the challenges they impose. More research is needed, and research initiatives will be developed at scientific conferences designed to review critical areas of cardiac development and etiology of disease in children. Financial support for such research initiatives must be increased. Educational programs on cardiovascular risk factors will be extended to children and their families. When these programs are coordinated with efforts in the community and in schools, they will reduce the prevalence of cardiovascular risk factors. The task force recommends that various departments and committees of the AHA use their resources for the benefit of children: for example, by developing more research initiatives for funding by the AHA or NHLBI and increasing legislative and regulatory efforts in the areas such as mandatory school health programs and tobacco advertising. It is hoped that in the next decade, through research and educational efforts, many advances in the prevention and treatment of cardiovascular diseases in the young will be realized.

Pulmonary valve eccentricity in d-transposition of the great arteries and implications for the arterial switch operation

Neoaortic valve regurgitation is a known complication of the arterial switch operation for d-transposition. Its etiology and long-term effects are undetermined. Observations of pathologic specimens from 67 patients with d-transposition of the great arteries with or without ventricular septal defects demonstrated that the pulmonary valve leaflets had unequal cusp sizes leading to eccentric closure. The posterior cusp was usually the largest and was anatomically related to the membranous ventricular septum and the anterior leaflet of the mitral valve. The right cusp was usually the smallest. Differences in cusp sizes were unrelated to age at death, sex or presence of a ventricular septal defect. To determine if eccentricity could be clinically detected, the pulmonary valves in 24 sequential patients with d-transposition were studied echocardiographically and angiographically. Aortic valves were studied for comparison. All pulmonary valves demonstrated eccentric closure in the long-axis echo plane, posterior in 15 patients and anterior in 9. Only 1 aortic valve showed eccentricity. Angiographic findings correlated with echo findings. Sixteen patients underwent arterial switch operations; 3 died. Twelve had angiography at 1 year. Eleven had neoaortic valve regurgitation: 5 grade I, 4 grade II and 2 grade III.

Insurability of the adolescent and young adult with heart disease. Report from the Fifth Conference on Insurability, October 3-4, 1991, Columbus, Ohio

By the mid-1990s there will be more than 500,000 young adults in the United States over the age of 21 with a cardiac malformation. Presently more than half of this population is denied insurance coverage entirely or in part because of their preexisting condition. Because some did not have coverage and because of uncertainty about whom to see for their cardiology care, patients assessed in NHS-II who were evaluated by their physician on an annual basis before the age of 21 were seen by a cardiologist only every 10 years after the age of 21. However, they have been shown by NHS-II to be well-educated, productive in the workplace, and to share an equal place in society with the general population. Their health-care costs are decidedly lower after the age of 21 than before. This group represents a microcosm of a general society of more than 37 million Americans who, for various reasons, are not insured. Dr. Wiener described an American health-care system in crisis. Smaller companies are no longer able to afford health insurance for all their employees, especially for those with preexisting conditions, because of an industry pricing concept based on a claims-experience standard rather than a community standard. The insurance industry, the government, and patients are demanding medical cost-containment. Health-care costs, 12.2% of the gross national product in 1990, are climbing, and no end to this increase is presently in sight.(ABSTRACT TRUNCATED AT 250 WORDS)

ACC/AHA guidelines for cardiac catheterization and cardiac catheterization laboratories. American College of Cardiology/American Heart Association Ad Hoc Task Force on Cardiac Catheterization

It is evident that the practice of cardiac catheterization has undergone, and continues to undergo, marked change. Most prominent are the recent very rapid proliferation of catheterization laboratories in general and the development of newer types of catheterization laboratory. No uniform definitions exist for these newer laboratories, so meaningful communication is difficult. The new settings are of particular concern because their location, mobility, organization, and ownership raise questions about the quality of patient care. Most difficult to address are the questions about patient safety and physician conflict of interest. There are no objective data in peer-reviewed literature to support the reported safety and cost savings of these newer settings. Through deliberations, surveys, interviews, and correspondence with the cardiology community embraced by the ACC and the AHA, the task force generally found that in freestanding catheterization laboratories, access to emergency hospitalization may be delayed, and appropriate oversight may be lacking. Additionally, opportunities for self-referral may be fostered and the perception of commercialism and entrepreneurial excess in practice created. All of these problems must be avoided. The growth and development of some freestanding facilities, particularly the mobile laboratories, do not seem to have been driven by an increased need in remote communities or for temporary support but rather almost exclusively by a desire to capture market share. Accordingly, a series of definitions, guidelines, and recommendations for the laboratories as well as for patient selection has been developed. The consensus was that a very restrictive and cautious attitude to the newer settings is appropriate at this time. The justification for development or expansion of cardiac catheterization services must be patient need. Documentation of this need must be based on objective estimates of the number of patients with known or suspected cardiac disease who meet generally accepted indications for laboratory study. Concerns about the lack of data from prospective clinical trials of patient safety in such a group necessitate a very cautious attitude toward any new catheterization services, in particular those without in-house cardiac surgical support. In view of the lack of appropriately controlled safety and need data for hospital-based, mobile, or freestanding laboratories operating without on-site (accessible by gurney) cardiac surgery facilities, the task force reaffirms the position that further development of these services cannot be endorsed at this time. In addition, there is reason for major concern that such proliferation in catheterization services may contribute to increasing costs and troubling ethical questions.

Balloon angioplasty for aortic recoarctation: results of Valvuloplasty and Angioplasty of Congenital Anomalies Registry

Balloon angioplasty was performed in 200 patients with recoarctation of the aorta in a multicenter prospective study. The average age at the time of the procedure was 7.0 years (range 1 month to 26 years). Systolic pressure (mean +/- standard deviation) in the ascending aorta decreased from 134.5 +/- 23.4 to 127.4 +/- 22.0 mm Hg. The descending aortic systolic pressure rose from 92.7 +/- 18.2 to 114.1 +/- 21.6 mm Hg. Peak systolic pressure differences decreased from 41.9 +/- 19.6 to 13.3 +/- 12.1 mm Hg. The diameter of the recurrent coarctation site increased from 5.2 +/- 2.9 to 8.9 +/- 3.4 mm. After angioplasty residual pressure differences of less than or equal to 20 mm Hg were found in 79.4% of the patients. Five patients died of complications related to the procedure (2.5%). Two deaths were directly related to the technical aspects of the procedure and 3 patients died because of the severity of the underlying disease. One additional patient had a cerebrovascular accident. Femoral artery complications occurred in 17 patients (8.5%) and 8 patients required surgical thrombectomy. Balloon angioplasty offers a satisfactory alternative to surgery for recurrent coarctation; both results and complications compare favorably with surgical therapy.