64-Slice ECG-gated computed tomographic angiography for assessment of coronary arteries in brachycephalic dogs with pulmonary stenosis.

BACKGROUND: Brachycephalic dogs with pulmonary stenosis are known to have a higher incidence of concurrent coronary artery abnormalities than non-brachycephalic breeds, which increases risk when performing balloon valvuloplasty. The use of ECG-gated CT angiography has been reported for the evaluation of coronary arteries in normal dogs and dogs with pulmonary stenosis. The purpose of this study was to report findings of coronary artery origination and morphology of main branches using ECG-gated CT angiography in brachycephalic dogs with pulmonary stenosis. METHODS: An ECG-gated CT angiographic protocol was used to image coronary artery anatomy in nine brachycephalic dogs with pulmonary stenosis. Images were assessed for quality as well as coronary artery morphology by one veterinary radiologist, one veterinary cardiologist and one veterinary radiology resident. RESULTS: All nine dogs had good to excellent image quality. Coronary artery anomalies were identified in three of nine dogs: one R2A anomaly, one L2A anomaly and one L2C anomaly. Two dogs were assessed to be poor balloon valvuloplasty candidates based on CT angiographic images. LIMITATION: Coronary artery morphology was not confirmed via postmortem examination in all patients. CONCLUSION: ECG-gated CT angiography is a minimally invasive imaging modality capable of diagnosing various coronary artery anomalies in brachycephalic dogs with pulmonary stenosis and aiding in the determination of patient candidacy for balloon valvuloplasty.

Integrative echocardiographic assessment of post-operative obstruction severity and restenosis after balloon valvuloplasty in 81 dogs with pulmonary stenosis.

INTRODUCTION/OBJECTIVES: Pulmonary stenosis (PS) is a congenital defect in the dog that is managed with balloon valvuloplasty (BV). Obstruction severity is routinely assessed using transthoracic echocardiography. The objectives of this study were to describe the short-term changes and long-term restenosis by retrospectively evaluating flow-dependent and flow-independent echocardiographic variables for dogs with PS after BV. ANIMALS, MATERIALS, AND METHODS: Medical records and stored echocardiographic images were reviewed from dogs that received BV for PS. The following echocardiographic variables were measured or calculated: maximum systolic ejection velocity (VmaxPV) and velocity-derived maximal pressure gradient (PV maxPG) across the pulmonary valve; ratio of aortic to pulmonary velocity time integral (VTIAV/VTIPV); ratio of aortic to pulmonary maximal velocity. RESULTS: Eighty-one dogs with PS that had a BV were included. Each of these dogs had pulmonary obstruction severity assessed in at least three timepoints. Forty-nine dogs had at least one additional examination performed, the last of which occurred a median of 504 days after the BV. Echocardiographic variables at the first follow-up had increased by a clinically relevant quantity in 20-34% of the dogs when comparing to the immediate post-BV examination. The last follow-up examination identified valve restenosis in 18-38% of the dogs in this study. Valve type and pre-BV obstruction severity did not have a significant effect (P > 0.1). CONCLUSIONS: For the assessment of BV efficacy, the immediate post-BV echocardiogram may not be as useful as the first follow-up examination several months later. Pulmonary restenosis after BV may be more prevalent than previously reported.

Echocardiographic assessment of right heart size and function in dogs with pulmonary valve stenosis.

INTRODUCTION/OBJECTIVES: We sought to determine the prevalence and clinical significance of right heart remodeling and right ventricular (RV) dysfunction in dogs with pulmonary valve stenosis (PS). We also sought to evaluate repeatability of several measurements of severity of PS, right heart size, and RV function in dogs with PS. ANIMALS, MATERIALS AND METHODS: Several indices of right atrial (RA) size and RV size and function were prospectively evaluated in 48 dogs with PS. Regression analysis was used to determine if indices of right heart size and function were independently associated with maximum transpulmonary pressure gradient (max PG) and adverse clinical findings (exercise intolerance, syncope, or right heart failure). Eight dogs underwent a second echocardiogram performed by the same operator to assess repeatability of the echocardiographic indices, which was quantified by coefficient of variation (CV) and repeatability coefficient. RESULTS: Increased RA size (81%), increased RV wall thickness (83%), and decreased tricuspid annular plane systolic excursion (TAPSE [81%]) were common. Right atrial size, end-diastolic RV area, and RV wall thickness were independently associated with max PG. Decreased TAPSE was independently associated with adverse clinical findings. All indices except RA area (18.6%) and RV systolic velocity (20.7%) had CVs <15%. Repeatability coefficients are available to help distinguish a true change versus measurement variability during serially obtained exams. CONCLUSIONS: Right heart remodeling and RV dysfunction are common in dogs with PS and are associated with echocardiographic and clinical severity. Results support the quantitative assessment of right heart size and function in dogs with PS.

3D-assessment of RVOT dimensions prior percutaneous pulmonary valve implantation: comparison of contrast-enhanced magnetic resonance angiography versus 3D steady-state free precession sequence.

To compare contrast-enhanced magnetic resonance angiography (ceMRA) and 3D steady-state free precession (SSFP) during systole and diastole for assessment of the right ventricle outflow tract (RVOT) in patients considered for percutaneous pulmonary valve implantation (PPVI) after tetralogy of Fallot (TOF) repair. We retrospectively evaluated 89 patients (male: 45, mean age 19 ± 8 years), who underwent cardiac-MRI after surgical TOF-repair. Datasets covering the whole heart in systole and diastole were acquired using ECG-gated 3D SSFP and non-gated ceMRA. Measurements were performed in SSFP-sequences and in ceMRA in the narrowest region of the RVOT to obtain the minimum, maximum and effective diameter. Invasive balloon sizing as the gold standard was available in 12 patients. The minimum diameter in diastolic SSFP, systolic SSFP and ceMRA were 21.4 mm (± 6.1 mm), 22.6 mm (± 6.2 mm) and 22.6 mm (± 6.0 mm), respectively. Maximum diameter was 29.9 mm (± 9.5 mm), 30.0 mm (± 7.0 mm) and 28.8 mm (± 8.1 mm) respectively. The effective diameter was 23.2 mm (± 5.7 mm), 27.4 mm (± 6.7 mm) and 24.4 mm (± 6.2 mm), differing significantly between diastole and systole (p < 0.0001). Measurements in ECG-gated SSFP showed a better inter- and intraobserver variability compared to measurements in non-ECG-gated ceMRA. Comparing invasive balloon sizing with our analysis, we found the highest correlation coefficients for the maximum and effective diameter measured in systolic SSFP (R = 0.99 respectively). ECG-gated 3D SSFP enables the identification and characterization of a potential landing zone for PPVI. The maximum and effective systolic diameter allow precise sizing for PPVI. Patients with TOF-repair could benefit from cardiac MRI before PPVI.

Pulmonary stenosis in complicated monochorionic twin pregnancies: prevalence, management and outcome.

OBJECTIVE: To review prevalence, management and prognostic factors of pulmonary stenosis (PS) in monochorionic diamniotic (MCDA) pregnancies complicated by twin-to-twin transfusion syndrome (TTTS). METHODS: Retrospective study over the last 10 years in a single referral center. We reviewed fetal echocardiography data of all MC twin cases with diagnosis of isolated PS. We assessed fetoscopy characteristics of those that underwent laser coagulation. We collected data regarding perinatal outcome, neonatal echocardiography and cardiac management. RESULTS: We found 24 cases of isolated PS among 2091 MCDA pregnancies. Among 1052 complicated MCDA that underwent fetal laser surgery, 22 (2.09%) developed PS of which 20 were diagnosed prenatally. Two cases were diagnosed in uncomplicated MCDA pregnancies (0.2%). Four of 22 (18.18%) cases with TTTS showed in utero regression after laser treatment. Thirteen newborns (65%) required valvular dilatation. Peak systolic velocities in the pulmonary artery trunk (PSV-PA) at diagnosis and the interval between the diagnosis of TTTS and that of PS were significantly different (p < 0.001 and p = 0.05 respectively) between PS requiring cardiac intervention and those who did not. CONCLUSION: An elevated PSV-PA at the time of PS diagnosis and a short time-interval between fetoscopic laser surgery and PS diagnosis are predictive of the need for interventional treatment after birth.

Utility of live/real time three-dimensional transesophageal echocardiography in the assessment and percutaneous intervention of bioprosthetic pulmonary valve stenosis.

Accurate echocardiographic evaluation of the pulmonary valve is technically difficult because of its close proximity to the left lung, which often limits decision making. Pulmonary valvotomy is the intervention of choice for symptomatic pulmonary valve stenosis, but fluoroscopy lacks appropriate real time anatomic detail. In this report, we present a case where direct imaging of the pulmonary valve with live/real time three-dimensional transesophageal echocardiography (3DTEE) aided in accurate evaluation and was then used to help guide and monitor successful valvuloplasty of a stenotic pulmonary valve bioprosthesis. We demonstrate that even in cases where two-dimensional (2D) evaluation of the pulmonary valve is difficult, the use of live/real time 3DTEE allows for accurate evaluation of bioprosthetic pulmonary valve structure and function, and enhances the precision and monitoring of percutaneous valvuloplasty.

Quantitative assessment of pulmonary regurgitation in patients with and without right ventricular tract obstruction.

BACKGROUND: There are concerns whether there is a difference in clinical utility of pulmonary regurgitation (PR) fraction (PRF) and PR volume (PRV) in subgroups of patients with isolated PR and individuals with combined PR and right ventricular outflow tract obstruction (RVOTO). The aim of the study was to compare PRF and PRV in patients with or without RVOTO. METHODS AND RESULTS: 82 consecutive patients after repair of tetralogy of Fallot (TOF) who underwent cardiovascular magnetic resonance and echocardiography were studied. There was no difference in PRF between patients with moderate and severe right ventricular (RV) dilatation (32±13% vs. 37±12%; p=0.18). Significant difference in PRV was observed between these groups (23±10 ml/m2 vs. 31±12 ml/m2, respectively; p=0.02). PRV had better ability than PRF in identification of severe RV dilatation, both in group with RVOTO [area under the curve (AUC) 0.82 vs. 0.72, p=0.005] and in patients without RVOTO (AUC 0.83 vs. 0.77, p=0.04). A strong correlation was seen between PRF and PRV both in patients with and without RVOTO [r=0.93, p<0.0001 and r=0.92, p<0.0001, respectively]. In both subgroups high variability of PRF was found in subjects with similar degree of PRV. CONCLUSIONS: PRV shows better ability than PRF in evaluating influence of PR on RV in patients after TOF repair, both in population with and without concomitant RVOTO.

Echocardiographic assessment of isolated pulmonary valve stenosis: which outpatient Doppler gradient has the most clinical validity?

Maximum instantaneous Doppler gradient has been the primary variable used to assess severity of pulmonary valve stenosis. However, recent observations suggest that outpatient maximum Doppler gradient often overstates clinical severity, as measured by catheter peak-to-peak gradient (PPG). This study sought to determine which outpatient Doppler gradient was most predictive of subsequently measured PPG. Ninety patients were included. Outpatient mean Doppler gradient showed the best correlation and agreement with the catheter PPG (r = 0.82, bias = -5 mm Hg). Maximum Doppler gradients, even when corrected for proximal velocity, consistently overestimated the PPG (bias = +21-26 mm Hg). Outpatient mean gradient was most predictive of subsequent PPG and should be used to determine whether to intervene for patients with isolated pulmonary valve stenosis. Use of only the maximum Doppler gradient to assess pulmonary valve stenosis will lead to a systematic overstatement of the severity of the stenosis.

Outpatient echocardiographic assessment of complex pulmonary outflow stenosis: Doppler mean gradient is superior to the maximum instantaneous gradient.

Evaluation of pulmonary outflow obstruction has focused on maximum instantaneous gradient (MIG). However, experience suggests that outpatient Doppler MIG often overstates the degree of stenosis. In this study of 132 patients with complex pulmonary stenosis, the mean Doppler gradient showed superior correlation and agreement with invasive peak-to-peak gradient (PPG) (r = 0.91, bias = -6 mm Hg). Agreement between mean gradient and PPG remained excellent for patients with prosthetic conduits (bias = -4 mm Hg). When PPG was 50 mm Hg more, both mean Doppler gradient and MIG corrected for prevalve velocity provided reasonable estimates of PPG (bias = -13 and +17 mm Hg, respectively). Uncorrected MIG remained significantly greater than PPG (bias = +27 mm Hg). Outpatient MIG consistently overstated subsequent PPG. In unselected patients with conduits or with PPG of 50 mm Hg or less, mean Doppler gradient provided the best prediction of PPG. These data provide a strong argument for the routine use of mean gradients in complex pulmonary stenosis.

Echocardiographic assessment of the right ventricular stress-velocity relationship under normal and chronic overload conditions.

UNLABELLED: The effects of chronic volume or pressure overload on the velocity of right ventricular ejection have not been previously well defined. We hypothesized that, as formerly shown for the left ventricle, there would be a direct relationship between the velocity of ejection and an estimate of systolic wall stress. METHODS: Echocardiograms of asymptomatic patients, not on cardiac medications, with either an isolated secundum atrial septal defect > or = 5 mm in diameter or isolated pulmonic stenosis with a peak instantaneous pressure gradient > or = 20 mmHg, were reviewed. Forty-one patients with an atrial septal defect and 34 with pulmonary stenosis met criteria, and were compared to age-matched normal controls. Total subjects were 127 with ages ranging from 1 day to 54 years. Right ventricular monoplane ejection fraction, ejection time corrected for heart rate (ETc), mean normalized systolic ejection rate (MNSERc) and meridianal peak-systolic wall stress (WSps) were measured. RESULTS: Compared to controls, ejection fractions were not significantly different, but WSps averaged 81% and 110% higher, ETc 8% and 9% longer, and MNSERc 5% and 9% slower in the atrial septal defect and pulmonary stenosis groups, respectively. Among all subjects WSps had a significant linear correlation with ETc (r = 0.61, P < 0.01), MNSERc (r =-0.46, P < 0.01), and ejection fraction (r =-0.19, P < 0.05). CONCLUSIONS: Increases in WSps cause an incremental slowing of MNSERc in the right ventricle, with a relationship that is linear over a wide range of normal and abnormal loading conditions.

Doppler-echocardiographic assessment of pulmonary regurgitation in adults with repaired tetralogy of Fallot: comparison with cardiovascular magnetic resonance imaging.

AIMS: The purpose of this study was to compare the noninvasive assessment of severity of pulmonary regurgitation with Doppler echocardiography versus cardiovascular magnetic resonance imaging (CMR) in adult patients with repaired tetralogy of Fallot (rTOF). METHODS: We studied 52 (22 females) consecutive patients (aged 32 +/- 2 years, 23 +/- 5 years after rTOF) using Doppler echocardiography and compared these findings with CMR. From the continuous-wave Doppler trace, the duration of pulmonary regurgitation and of total diastole was measured and the ratio between the 2 was defined as pulmonary regurgitation index (PRi). Pulmonary regurgitant fraction (PRF) was assessed with flow phase velocity mapping with CMR. RESULTS: Patients were divided into 2 groups according to the median value (24.5%) of PRF measured by CMR: Group I (26 patients) with PRF < or =24.5% and Group II with PRF >24.5%. There was no difference between patients' age, sex, or age at repair between the 2 groups. More patients from Group II had a right ventricular outflow or transannular patch repair compared to Group I (12/26 [46%] vs 6/26 [23%], P <.01). Mean pulmonary regurgitation time was shorter (340 +/- 60 vs 440 +/- 135 ms, P =.001) and PRi was lower (0.61 +/- 0.11 vs 0.91 +/- 0.11, P <.001) in Group II compared to Group I. Color Doppler regurgitant jet was also broader in Group II (1.4 +/- 0.4 vs 0.7 +/- 0.5 cm, P <.001), signifying more severe pulmonary regurgitation. Doppler-measured PRi correlated closely with CMR regurgitant fraction (r = -0.82, P <.001) and with color Doppler pulmonary regurgitant jet width (r = -0.66, P <.001); the latter correlated with PRF assessed with CMR (r = 0.72, P <.001). A PRi <0.77 had 100% sensitivity and 84.6% specificity for identifying patients with pulmonary regurgitant fraction >24.5%, with a predictive accuracy of 95%. Furthermore, echocardiographically-assessed right ventricular end-diastolic dimensions correlated with CMR end-diastolic volume index (r = 0.49, P <.001 ). CONCLUSIONS: Pulmonary regurgitation is common in asymptomatic adults with rTOF. Severity of pulmonary regurgitation and its effects on right ventricular dimensions in these patients can be assessed noninvasively by Doppler echocardiography and CMR, with reasonable agreement between the 2 techniques.

Assessment of pulmonary artery stenosis using freehand "flock of birds" digital color three-dimensional echocardiographic reconstruction.

Pulmonary artery (PA) trunk or branch PA stenosis is commonly found in patients with congenital heart disease. The aim of the present study was to evaluate the freehand "Flock of Birds" color Doppler three-dimensional (3D) reconstruction on a modeled-segment imitating PA stenosis. First, a PA model was created from latex tubes to simulate the main PA and its main branches with baseline cross-sectional areas (CSA) of 0.7 cm2. A series of narrowed segments in the right and left PA were created. The cross-sections of the smallest area ranged from 0.13 to 0.59 cm2 and stenotic segmental length ranged from 0.17 to 1.80 cm. The dimensions of these elements mounted on to the model were verified by intravascular ultrasound (IVUS) imaging. Next, pulsatile flows at 60 beats/ min were generated through the system. A GE/VingMed System FiVe with magnetic locator system (Flock of Birds) on a 3.5 MHz transducer was used to acquire a freehand sweep for ECG gated 3D data acquisition of color Doppler flows through the model. The images were reconstructed by EchoPac 3D software and the morphology of the stenotic elements were determined. The results revealed that the narrowest CSA determined by the 3D color flow cast of the pulmonary artery were in excellent agreement with IVUS CSA (r = 0.98, p < 0.001, SEE = 0.04 cm2). The stenotic length estimated from 3D was also in good agreement with the IVUS (r = 0.98, p < 0.001, SEE = 0.03 cm). In addition, complex morphology of the stenosis was well visualized by this technique. As a result, the noninvasive free-hand digital color 3D echocardiography can be adopted for the accurate assessment of the severity and morphology of PA stenosis in patients with congenital heart diseases.

Assessment of fetal pulmonic stenosis by ultrasonography.

This study was designed to determine (1) the value of Doppler echocardiography in depicting the presence of a fetal pulmonary stenosis, (2) its reliability in the assessment of the severity of the lesion, and (3) the usefulness of additional markers from the left side of the heart as criteria of severity. Fourteen pregnant ewes were included in this study (gestational age, 90 to 120 days). Banding of the fetal main pulmonary artery created mild (n = 3), moderate (n = 3), and severe (n = 5) stenosis. Three lambs were sham operated. Intrauterine fetal Doppler echocardiographic data obtained 15 days after surgery were compared with preoperative values. Peak velocities recorded through the band increased linearly from baseline in the groups with mild and moderate stenosis but did not show any further increase in the group with severe stenosis. Compared with the sham-operated group, right ventricular output in the group with stenosis was either similar or reduced significantly. The increase in right ventricular free wall thickness was significantly greater in the groups with stenosis compared with that of the sham-operated group; the correlation with the degree of severity was r = 0.65 and p < 0.05. A A stronger positive correlation was found between the severity of stenosis and aortic valve diameters: r = 0.82 and p < 0.01. The strongest correlation was found for right ventricular/left ventricular outputs (r = 0.92; p < 0.001). Thus Doppler peak velocities through the obstruction can help detect pulmonic stenosis but are not reliable for the assessment of its severity during fetal life. Other ultrasound measurements such as the size of the aortic anulus and especially the ratio of right ventricular/left ventricular output could be used as sensitive markers of the severity of stenosis.

Cost-effectiveness of echocardiography for evaluation of children with murmurs.

Echocardiography is widely accepted as an accurate diagnostic test to evaluate heart murmurs in children, however its costs, and the ubiquity of murmurs in children, discourage its universal application. The purpose of this article is to identify some clinical circumstances in which the cost of echocardiography is justified for the evaluation of heart murmurs in infants and children. Eight common clinical problems were selected in which a heart murmur is present and a diagnosis is called for. Effectiveness of echocardiography and less costly clinical diagnostic methods in these settings were compared. In some circumstances, echocardiography is worth the cost, because clinical evaluation is unacceptably insensitive to important disease (the premature infant with a murmur which might represent a patent ductus arteriosus, the infant with a dysmorphic syndrome and a murmur). In others, the expert clinical examination is highly accurate (the asymptomatic child with a heart murmur) and is preferred over the echocardiogram as the initial diagnostic approach on the grounds of cost. When the expert clinical examination suggests minor structural heart disease, a continuum of echocardiographic cost-effectiveness relative to the expert clinical examination exists between these extremes depending on the working diagnosis. A threshold has not yet been defined at any point on this continuum above which the public will demand the greater diagnostic detail available echocardiographically, and below which the public will refuse to accept its greater cost. Quantitative formal cost-effectiveness analysis of echocardiography for evaluation of heart murmur in infants and children is not yet feasible because the benefits of echocardiography are indirect, dependent upon the as yet unmeasured benefits of correct management of congenital heart defects. To go beyond simple comparison of efficacy of echocardiography with less costly methods, further work is required in outcomes research in congenital heart disease.

Cardiologic abnormalities in Noonan syndrome: phenotypic diagnosis and echocardiographic assessment of 118 patients.

OBJECTIVES: The purpose of this study was to determine the incidence of cardiologic abnormalities in Noonan syndrome. BACKGROUND: The incidence of cardiac abnormalities in Noonan syndrome remains unknown, largely because of such difficulties as assembling a substantial cohort, ensuring a correct phenotypic diagnosis and providing accurate definitions of the most frequent abnormalities--pulmonary stenosis and left ventricular hypertrophy. METHODS: A cohort of 145 patients was assembled, and before cardiologic assessment two independent geneticists scrutinized the phenotype. The diagnosis was confirmed in 118 patients, and they were studied by two-dimensional and Doppler echocardiography. RESULTS: A dysplastic pulmonary valve was present in eight patients (7%) and was associated with significant stenosis in six (75%) of the eight. Significant stenosis was present in 22 (20%) of 110 patients without dysplasia. Left ventricular hypertrophy was present in 29 patients (25%) without significant pulmonary stenosis. Localized anterior septal hypertrophy was the most common pattern in 12 (41%) of 29 patients. Diffuse hypertrophy involving the entire septum and the free wall was present in nine patients (31%) and was severe (> 1.7 cm) in five. Other abnormalities included secundum atrial septal defects (10%). CONCLUSIONS: The high incidence of cardiac abnormalities suggests that echocardiographic and Doppler evaluation of patients with the Noonan phenotype is important because it will aid in genetic counseling and in the assessment of the natural history of--and, ultimately, identification of the gene(s) responsible for--Noonan syndrome.

Assessment of right ventricular overload by a thallium-201 SPECT study in children with congenital heart disease.

Thallium-201 planar and SPECT studies were performed in 38 children with congenital heart disease using high-resolution three-headed SPECT. The 201Tl total or average right ventricular-to-left ventricular (RV/LV) count ratios were measured by summed short-axis images. In the planar study, the RV/LV systolic pressure ratio correlated with 201Tl RV/LV average count ratio (r = 0.91) better than that in the SPECT study (r = 0.78). However, in the SPECT study, patients with atrial septal defect (n = 9), ventricular septal defect (n = 13), tetralogy of Fallot and double outlet right ventricle (n = 6) showed a characteristic distribution in the plot of RV/LV pressure ratio versus 201Tl RV/LV total count ratio. A prospective study showed that the RV/LV average count ratio was a good predictor of RV/LV pressure ratio (n = 19, r = 0.91). Three-headed SPECT is useful for pediatric cardiac studies, and the overload types found in congenital heart disease seemed to be differentiated by the SPECT study.