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Biomedical subjects

Steven D Colan

Publications and source records attributed to Steven D Colan.

At least 37 records · Page 2Linked to original sources
PubMed2005

Left heart growth, function, and reintervention after balloon aortic valvuloplasty for neonatal aortic stenosis.

BACKGROUND: Transcatheter balloon aortic valvuloplasty (BAVP) has become the first-line treatment for critical aortic stenosis (AS) in neonates. However, little is known about the growth and function of left heart structures or about patterns of reintervention on the left heart after neonatal BAVP. METHODS AND RESULTS: Between 1985 and 2002, 113 patients underwent neonatal BAVP at < or =60 days of age. There were 16 early deaths (14%), with a significant decrease from 1985 to 1993 (22%) to 1994 to 2002 (4%), and 6 patients had successful early conversion to a univentricular circulation. In the short term, the mean relative gradient reduction was 54+/-26%, and significant aortic regurgitation (AR) developed in 15% of patients. The 91 early survivors with a biventricular circulation were followed up for 6.3+/-5.3 years, during which time there was a steady increase in the frequency of significant AR. Freedom from moderate or severe AR was 65% at 5 years. In almost all patients with a baseline aortic annulus z score less than -1, the annulus diameter increased to within the normal range within 1 to 2 years. Similarly, left ventricular (LV) end-diastolic dimension z scores, which ranged from -5 to 7.5 before BAVP, normalized within 1 to 2 years in nearly all patients with a predilation z score less than -1. Among early survivors with a biventricular circulation, reintervention-free survival on the LV outflow tract was 65% at 1 year and 48% at 5 years, with younger age, higher pre- and post-BAVP gradients, and a larger balloon-annulus diameter ratio associated with decreased reintervention-free survival (P<0.01). Seventeen surgical interventions were performed on the aortic valve in 15 patients, including replacement in 7. Survival free from aortic valve replacement was 84% at 5 years. CONCLUSIONS: BAVP for AS during the first 60 days of life results in short-term relief of AS in the majority of patients. Among early survivors, initially small left heart structures may be associated with worse subacute outcomes but typically normalize within 1 year. Reintervention for residual/recurrent AS or iatrogenic AR is relatively common, particularly during the first year after BAVP, but aortic valve replacement during early childhood is seldom necessary.

Aortic Valve↗
PubMed2005

Mild dilated cardiomyopathy and increased left ventricular mass predict mortality: the prospective P2C2 HIV Multicenter Study.

BACKGROUND: Many HIV-infected children die with cardiac abnormalities. We sought to understand the course of these HIV-associated abnormalities and their impact on all-cause mortality. METHODS: We describe longitudinal changes in left ventricular (LV) structure and function and mortality in 185 children vertically infected with HIV. Serial cardiac data were obtained from 0.1 to 10 years of age. Age- or body surface area-adjusted z scores were calculated for 10 echocardiographic outcomes. RESULTS: Median age at first echocardiogram was 2 years (range 0.2-9.4 years); median follow-up was 3.6 years (range 0-6.3 years). The 5-year cumulative incidence of congestive heart failure was 12.3%. Mean fractional shortening z scores declined from -0.65 at 1 year of age to -1.47 at 3 years of age without further decline between 3 and 10 years of age. Among children with 2 echocardiograms performed in the first year of follow-up, mild LV dysfunction (fractional shortening of < -2 SD on both echocardiograms) was present in 29 (18%) of 158 children. For these 29 children, the 5-year mortality was 55.4%. Left ventricular mass z scores were elevated at 1 year (mean z score 0.68, P < .001) and remained elevated throughout follow-up. In the 8 children with LV mass z score of > 2 SD on both initial and follow-up echocardiograms, the 5-year mortality was 75%. CONCLUSION: In HIV-infected children, LV structure and function progressively deteriorated in the first 3 years of life, resulting in subsequent persistent mild LV dysfunction and increased LV mass. Chronic mild depression of LV function and elevated LV mass were associated with higher all-cause mortality.

Cardiomyopathy, Dilated↗
PubMed2005

Midwall shortening after coarctation repair: the effect of through-plane motion on single-plane indices of left ventricular function.

Left ventricular midwall function is increased after repair of coarctation of the aorta (CoA). The cause is unclear. This study aimed to examine the variance between fiber shortening derived from 3-dimensional models of myocardial deformation, and 1- and 2-dimensional indices of left ventricular systolic function. In all, 15 young adults after CoA and 15 matched control subjects were recruited. Endocardial and midwall fractional shortening were calculated using M-mode echocardiography. Ejection fraction, midwall fractional shortening, and myocardial deformation were calculated or measured from magnetic resonance (MR) imaging. Echocardiographic and cine-MR imaging midwall fractional shortening were increased after CoA (P = .02 and < .001). In contrast, 3-dimensional MR tagging demonstrated normal midwall circumferential shortening and decreased longitudinal shortening in the CoA group (P < .01). Cine MR midwall shortening, recalculated to allow for through-plane motion, was similar to tagged midwall shortening, with no difference between the CoA and control groups. After CoA, measures of left ventricular function systematically overestimate midwall fiber shortening unless the methodology accounts for through-plane motion.

Adult↗
PubMed2005

Accuracy of echocardiography in low birth weight infants with congenital heart disease.

OBJECTIVE: Echocardiography has been shown to be highly accurate in infants and children, but its accuracy has not been studied in detail in low birth weight (LBW) infants with structural congenital heart disease (CHD). This study was undertaken to examine the diagnostic accuracy of echocardiography in the evaluation of CHD in these infants. METHODS: All echocardiograms performed between 1995 and 2000 on infants who had structural CHD and weighed 2.5 kg, matched for type of CHD, were control subjects (n = 319). The results of initial echocardiograms were compared for diagnostic accuracy with consensus diagnoses on the basis of all confirmatory data available. An observer who was blinded to patient group graded a sample of randomly selected echocardiograms (n = 100) for technical quality. RESULTS: There were 13 major diagnostic errors in the LBW infants (5.2%) and 6 in the control subjects (1.9%). There were 20 minor errors in the LBW group (8.0%) and 21 in the control subjects (6.6%). The technical quality scores of the 2 groups were not significantly different, but a higher proportion of the LBW studies were graded as "poor" or "borderline" quality, compared with the control subjects (40% vs 28%). The majority (54%) of major errors in the LBW infants could potentially be explained by alterations in blood flow secondary to pulmonary hypertension. CONCLUSIONS: Although echocardiography is an accurate imaging modality in premature and LBW infants with structural CHD, the incidence of clinically important diagnostic errors is higher than in infants who weigh >2.5 kg. As surgical and transcatheter interventions are extended to this population, heightened awareness of clinicians to pitfalls of echocardiography in this group of patients is warranted.

Diagnostic Errors↗
PubMed2005

Cardiac changes associated with growth hormone therapy among children treated with anthracyclines.

OBJECTIVE: The objective was to assess the cardiac effects of growth hormone (GH) therapy. Anthracycline-treated childhood cancer survivors frequently have reduced left ventricular (LV) wall thickness and contractility, and GH therapy may affect these factors. METHODS: We examined serial cardiac findings for 34 anthracycline-treated childhood cancer survivors with several years of GH therapy and baseline cardiac z scores similar to those of a comparison group (86 similar cancer survivors without GH therapy). RESULTS: LV contractility was decreased among GH-treated patients before, during, and after GH therapy (-1.08 SD below the age-adjusted population mean before therapy and -1.88 SD 4 years after therapy ceased, with each value depressed below normal). Contractility was higher in the control group than in the GH-treated group, with this difference being nearly significant. The GH-treated children had thinner LV walls before GH therapy (-1.38 SD). Wall thickness increased during GH therapy (from -1.38 SD to -1.09 SD after 3 years of GH therapy), but the effect was lost shortly after GH therapy ended and thickness diminished over time (-1.50 SD at 1 year after therapy and -1.96 SD at 4 years). During GH therapy, the wall thickness for the GH-treated group was greater than that for the control group; however, by 4 years after therapy, there was no difference between the GH-treated group and the control group. CONCLUSIONS: GH therapy among anthracycline-treated survivors of childhood cancer increased LV wall thickness, but the effect was lost after therapy was discontinued. The therapy did not affect the progressive LV dysfunction.

Adolescent↗
PubMed2004

Theoretical and empirical derivation of cardiovascular allometric relationships in children.

Basic fluid dynamic principles were used to derive a theoretical model of optimum cardiovascular allometry, the relationship between somatic and cardiovascular growth. The validity of the predicted models was then tested against the size of 22 cardiovascular structures measured echocardiographically in 496 normal children aged 1 day to 20 yr, including valves, pulmonary arteries, aorta and aortic branches, pulmonary veins, and left ventricular volume. Body surface area (BSA) was found to be a more important determinant of the size of each of the cardiovascular structures than age, height, or weight alone. The observed vascular and valvar dimensions were in agreement with values predicted from the theoretical models. Vascular and valve diameters related linearly to the square root of BSA, whereas valve and vascular areas related to BSA. The relationship between left ventricular volume and body size fit a complex model predicted by the nonlinear decrease of heart rate with growth. Overall, the relationship between cardiac output and body size is the fundamental driving factor in cardiovascular allometry.

Adolescent↗
PubMed2004

Morphology of bicuspid aortic valve in children and adolescents.

OBJECTIVES: The aim of this study was to determine the relationship between aortic valve morphology and valve dysfunction. BACKGROUND: The morphology of the bicuspid or bicommissural aortic valve (BAV) may predict the severity of valve dysfunction. Therefore, we assessed the relationship between BAV, aortic coarctation, and the degree of valve pathology in children. METHODS: A retrospective review of 1,135 patients with BAV who were identified between 1986 and 1999 was performed. Patients younger than 18 years of age with BAV that was identifiable via echocardiography were included. The most recent or last study of each patient before intervention or endocarditis was reviewed. Mild stenosis was defined as a valve gradient > or =2 m/s, moderate or greater aortic stenosis as > or =3.5 m/s. Aortic regurgitation was quantified using standard criteria. RESULTS: Median age was 3 years (range, 1 day to 17.9 years), and 67% of the patients were male. Right-coronary and left-coronary leaflet fusion were the most common types of BAV (70%). Aortic stenosis that was moderate or greater was observed most often in patients with right-coronary and non-coronary leaflet fusion (odds ratio 2.4, 95% confidence interval 1.6 to 3.6; p < or = 0.001). Similarly, right-coronary and non-coronary leaflet fusion was more often associated with moderate aortic regurgitation or greater (odds ratio 2.4, 95% confidence interval 1.2 to 4.7; p = 0.01). The majority of patients with aortic coarctation had fusion of the right-coronary and left-coronary leaflets (89%), and aortic coarctation was associated with lesser degrees of valve stenosis or regurgitation. CONCLUSIONS: Analysis of BAV morphology is of clinical and prognostic relevance. Fusion of the right-coronary and non-coronary leaflets was associated with more significant valve pathology, whereas fusion of the right-coronary and left-coronary leaflets was associated overwhelmingly with aortic coarctation and less aortic valve pathology.

Adolescent↗
PubMed2004

Balloon dilation of severe aortic stenosis in the fetus: potential for prevention of hypoplastic left heart syndrome: candidate selection, technique, and results of successful intervention.

BACKGROUND: Preventing the progression of fetal aortic stenosis (AS) to hypoplastic left heart syndrome (HLHS) requires identification of fetuses with salvageable left hearts who would progress to HLHS if left untreated, a successful in utero valvotomy, and demonstration that a successful valvotomy promotes left heart growth in utero. Fetuses meeting the first criterion are undefined, and previous reports of fetal AS dilation have not evaluated the impact of intervention on in utero growth of left heart structures. METHODS AND RESULTS: We offered fetal AS dilation to 24 mothers whose fetuses had AS. At least 3 echocardiographers assigned a high probability that all 24 fetuses would progress to HLHS if left untreated. Twenty (21 to 29 weeks' gestation) underwent attempted AS dilation, with technical success in 14. Ideal fetal positioning for cannula puncture site and course of the needle (with or without laparotomy) proved to be necessary for procedural success. Serial fetal echocardiograms after intervention demonstrated growth arrest of the left heart structures in unsuccessful cases and in those who declined the procedure, while ongoing left heart growth was seen in successful cases. Resumed left heart growth led to a 2-ventricle circulation at birth in 3 babies. CONCLUSIONS: Fetal echocardiography can identify midgestation fetuses with AS who are at high risk for developing HLHS. Timely and successful aortic valve dilation requires ideal fetal and cannula positioning, prevents left heart growth arrest, and may result in normal ventricular anatomy and function at birth.

Aortic Valve Stenosis↗
PubMed2004

Long-term predictors of aortic root dilation and aortic regurgitation after arterial switch operation.

BACKGROUND: Neo-aortic root dilation (ARD) and neo-aortic regurgitation (AR) may be progressive after arterial switch operation (ASO) for d-loop transposition of the great arteries (dTGA). We sought to identify predictors of ARD and AR after ASO. METHODS AND RESULTS: 335 patients were identified who underwent ASO for dTGA with intact ventricular septum or ventricular septal defect (VSD), including double-outlet right ventricle (DORV), before 2001 with at least 1 postoperative echocardiogram at our institution, at least 1 year after ASO, and no previous atrial switch procedure (median follow-up of 5.0 years). Probability of freedom from ARD was 97%, 92%, 82%, and 51%, from at least moderate AR was 98%, 97%, 96%, and 93%, and from neo-aortic valve or root surgery was 100%, 100%, 99%, and 95%, at 1, 2, 5, and 10 years, respectively. For patients in whom ARD developed, progressive dilation was not observed during late follow-up. By Kaplan-Meier method, independent predictors of ARD, with neo-aortic root z-score of > or =3.0, were previous pulmonary artery band (PAB) (P=0.002, hazard ratio [HR]=2.4) and later time period when ASO was performed (P<0.002, HR=19.0). Risk factor for at least moderate AR was age > or =1 year at ASO (P=0.002, HR=5.8), which was closely related to VSD repair at ASO (P<0.001) and previous PAB. CONCLUSIONS: Significant ARD and AR continue to develop over time after ASO, but ARD does not tend to be progressive during late follow-up. Previous PAB was a significant risk factor for ARD. Older age at time of ASO, presence of VSD, and previous PAB were risk factors for AR.

Abnormalities, Multiple↗
PubMed2004

Cardiovascular status in long-term survivors of Hodgkin's disease treated with chest radiotherapy.

PURPOSE: Cardiovascular status was assessed in 48 Hodgkin's disease (HD) survivors at a median of 14.3 years (range, 5.9 to 27.5 years) after diagnosis because they may be at increased risk for cardiovascular abnormalities. PATIENTS AND METHODS: Patients completed the Short-Form 36 quality-of-life instrument and were screened by echocardiography, exercise stress testing, and resting and 24-hour ECG. RESULTS: All patients received mediastinal irradiation (median, 40.0 Gy; range, 27.0 to 51.7 Gy) at a median age of 16.5 years (range, 6.4 to 25.0 years). Four patients received an anthracycline. Although every patient described their health as good or better, and none had symptomatic heart disease at screening, all but one had cardiac abnormalities on screening. Restrictive cardiomyopathy was suggested by reduced average left ventricular (LV) dimension (P < .001) and mass (P < .001), without increased LV wall thickness. Significant valvular defects were present in 42%; 75% had conduction defects. One survivor developed complete heart block shortly after the study visit. Autonomic dysfunction was suggested by a monotonous heart rate in 57%, persistent tachycardia in 31%, and blunted hemodynamic responses to exercise in 27%. Peak oxygen uptake (VO2max) during exercise, a predictor of mortality in heart failure, was significantly reduced (< 20 mL/kg/m2) in 30% of survivors. VO2max was correlated with increasing fatigue, increasing shortness of breath (both, r = -0.35; P =. 02), and decreasing physical component score on the SF-36 (r = 0.554; P = .00017). CONCLUSION: A variety of unsuspected, clinically significant cardiovascular abnormalities are common in long-term survivors of HD who are treated at a young age with mediastinal irradiation. We recommend serial, comprehensive cardiac screening of HD survivors who fit this profile.

Adolescent↗
PubMed2004

Improved outcomes of pediatric dilated cardiomyopathy with utilization of heart transplantation.

OBJECTIVES: We studied the outcomes of pediatric patients diagnosed with dilated cardiomyopathy (DCM) and their relation to epidemiologic and echocardiographic variables at the time of presentation. BACKGROUND: The outcome of pediatric DCM patients ranges from recovery to a 50% to 60% chance of death within five years of diagnosis. The impact of heart transplantation and other emerging therapies on the outcomes of pediatric DCM patients is uncertain. METHODS: We performed a retrospective study of the outcomes in 91 pediatric patients diagnosed with DCM from 1990 to 1999. Routine therapy included use of digoxin, diuretics, angiotensin-converting enzyme inhibitors, and heart transplantation. RESULTS: At the time of last follow-up, 11 patients (12%) had died without transplantation; 20 (22%) underwent transplantation; 27 (30%) had persistent cardiomyopathy; and 33 (36%) had recovery of left ventricular systolic function. Overall actuarial one-year survival was 90%, and five-year survival was 83%. However, actuarial freedom from "heart death" (death or transplantation) was only 70% at one year and 58% at five years. Multivariate analysis found age <1 year (hazard ratio 7.1), age >12 years (hazard ratio 4.5), and female gender (hazard ratio 3.0) to be significantly associated with a greater risk of death or transplantation and a higher left ventricular shortening fraction at presentation (hazard ratio 0.92), with a slightly decreased risk of death or transplantation. CONCLUSIONS: Pediatric DCM patients continue to have multiple outcomes, with recovery of left ventricular systolic function occurring most frequently. Utilization of heart transplantation has led to improved survival after the diagnosis of pediatric DCM.

Adolescent↗
PubMed2004

The effect of dexrazoxane on myocardial injury in doxorubicin-treated children with acute lymphoblastic leukemia.

BACKGROUND: Doxorubicin chemotherapy is very effective in children with acute lymphoblastic leukemia (ALL) but also injures myocardial cells. Dexrazoxane, a free-radical scavenger, may protect the heart from doxorubicin-associated damage. METHODS: To determine whether dexrazoxane decreases doxorubicin-associated injury of cardiomyocytes, we randomly assigned 101 children with ALL to receive doxorubicin alone (30 mg per square meter of body-surface area every three weeks for 10 doses) and 105 to receive dexrazoxane (300 mg per square meter) followed immediately by doxorubicin. Serial measurements of serum cardiac troponin T were obtained in 76 of 101 patients in the doxorubicin group and 82 of 105 patients in the group given dexrazoxane and doxorubicin. A total of 2377 serum samples (mean, 15.1 samples per patient) were obtained before, during, and after treatment with doxorubicin. Troponin T levels were evaluated in a blinded fashion to determine whether they were elevated (>0.01 ng per milliliter)--the primary end point--or extremely elevated (>0.025 ng per milliliter). RESULTS: Elevations of troponin T occurred in 35 percent of the patients (55 of 158). Patients treated with doxorubicin alone were more likely than those who received dexrazoxane and doxorubicin to have elevated troponin T levels (50 percent vs. 21 percent, P<0.001) and extremely elevated troponin T levels (32 percent vs. 10 percent, P<0.001). The median follow-up was 2.7 years. The rate of event-free survival at 2.5 years was 83 percent in both groups (P=0.87 by the log-rank test). CONCLUSIONS: Dexrazoxane prevents or reduces cardiac injury, as reflected by elevations in troponin T, that is associated with the use of doxorubicin for childhood ALL without compromising the antileukemic efficacy of doxorubicin. Longer follow-up will be necessary to determine the influence of dexrazoxane on echocardiographic findings at four years and on event-free survival.

Antibiotics, Antineoplastic↗
PubMed2004

Evidence of adverse ventricular interdependence in patients with atrial septal defects.

Right ventricular (RV) volume overload is associated with left ventricular (LV) distortion and dysfunction. The availability of transcatheter device closure of secundum atrial septal defect (ASD) provides an ideal model for investigating the immediate effects of elimination of RV volume overload and avoiding the confounding effects of surgery on LV function. Echocardiograms before and after device closure of ASD were analyzed for ejection fraction, percent changes in cross-sectional area and circumference, percent changes in free wall and septal endocardial lengths, and eccentricity. We enrolled 34 patients (median age 9 years) who underwent device closure of ASD (pulmonary to systemic shunt 1.6 +/- 0.4). Ejection fraction and LV end-diastolic volume, reflective of chamber preload, were significantly decreased in the presence of RV volume overload and normalized after defect closure with normalization of LV shape. Altered LV geometry secondary to RV volume overload was associated with regional variation in preload,such that diastolic circumference, a surrogate of myofiber preload, increased after closure of ASD secondary to a small increase in LV free wall arc length in conjunction with a much more significant increase in septal length. Thus, LV dysfunction associated with RV volume overload is secondary to altered chamber geometry and decreased myofiber preload. This physiology is immediately reversible and is independent of heart rate and afterload.

Child↗
PubMed2004

Association between congenital cardiovascular malformations and neuroblastoma.

OBJECTIVE: We explored the association between neuroblastoma and congenital cardiovascular malformations (CCM), previously described in case reports. STUDY DESIGN: Echocardiogram and chart reviews of a series of 158 patients with neuroblastoma and a control group of 192 children with leukemia were performed. The proportion of patients with CCM in each group was compared. RESULTS: Fourteen of the 70 (20%) patients with neuroblastoma and echocardiography had CCM, compared with 7 of the 192 (3.6%) patients with leukemia with echocardiograms (P=.0001). If all of the patients with neuroblastoma without echocardiograms (n=88) are considered to have normal cardiac anatomy, this difference remains significant (14 of 158 patients with neuroblastoma have CCM detected [8.9%] versus 7 of 192 patients with leukemia [3.6%]; P=.045). Neural crest-derived CCM were more common in patients with neuroblastoma, detected in 5 of 70 patients with neuroblastoma versus 2 of 192 patients with leukemia (P=.016). Congenital cardiovascular malformations in patients with neuroblastoma were associated with a cancer diagnosis at age less than 1 year and a lower neuroblastoma stage, but there was no association with tumor MYCN amplification. CONCLUSIONS: Neuroblastoma and CCM may be associated. We recommend echocardiography for CCM screening in patients with newly diagnosed neuroblastoma.

Adolescent↗