Maximal Instantaneous Gradient Research Articles

Ventricular septal defect Doppler peak gradient underestimates right ventricular systolic pressure in the presence of right bundle branch block.

Estimation of the right ventricular systolic pressure (RVSP) using echocardiographically derived maximal instantaneous gradient across the ventricular septal defect is a well-utilized tool, which can potentially underestimate the RVSP in patients with conduction abnormalities as such its utility in these patients is questionable.

Repetitive Squat-to-Stand Provocation of Dynamic Left Ventricular Outflow Tract Obstruction in Hypertrophic Cardiomyopathy

Left ventricular outflow tract (LVOT) obstruction is a determinant in the management of patients with hypertrophic cardiomyopathy, including candidacy for septal reduction therapy and risk stratification for sudden cardiac death. 1 Elliott P.M. Gimeno J.R. Tomé M.T. Shah J. Ward D. Thaman R. et al. Left ventricular outflow tract obstruction and sudden death risk in patients with hypertrophic cardiomyopathy. Eur Heart J. 2006; 27: 1933-1941 Crossref PubMed Scopus (262) Google Scholar ,2 Ommen S.R. Mital S. Burke M.A. Day S.M. Deswal A. Elliott P. et al. 2020 AHA/ACC guideline for the diagnosis and treatment of patients with hypertrophic cardiomyopathy. J Am Coll Cardiol. 2020; 76: e159-e240 Crossref PubMed Scopus (136) Google Scholar Obstruction is defined as a maximal instantaneous gradient ≥ 30 mm Hg, and severe obstruction is defined as a maximal instantaneous gradient ≥ 50 mm Hg. 2 Ommen S.R. Mital S. Burke M.A. Day S.M. Deswal A. Elliott P. et al. 2020 AHA/ACC guideline for the diagnosis and treatment of patients with hypertrophic cardiomyopathy. J Am Coll Cardiol. 2020; 76: e159-e240 Crossref PubMed Scopus (136) Google Scholar Several provocative maneuvers have been used to elicit latent obstruction, including the Valsalva maneuver, amyl nitrite inhalation, and exercise on a treadmill or bike. 3 Marwick T.H. Nakatani S. Haluska B. Thomas J.D. Lever H.M. Provocation of latent left ventricular outflow tract gradients with amyl nitrite and exercise in hypertrophic cardiomyopathy. Am J Cardiol. 1995; 75: 805-809 Abstract Full Text PDF PubMed Scopus (74) Google Scholar , 4 Jensen M.K. Havndrup O. Pecini R. Dalsgaard M. Hassager C. Helqvist S. et al. Comparison of Valsalva manoeuvre and exercise in echocardiographic evaluation of left ventricular outflow tract obstruction in hypertrophic cardiomyopathy. Eur J Echocardiogr. 2010; 11: 763-769 Crossref PubMed Scopus (24) Google Scholar , 5 Shah J.S. Esteban M.T.T. Thaman R. Sharma R. Mist B. Pantazis A. et al. Prevalence of exercise-induced left ventricular outflow tract obstruction in symptomatic patients with non-obstructive hypertrophic cardiomyopathy. Heart. 2008; 94: 1288-1294 Crossref PubMed Scopus (165) Google Scholar During a recent shortage of amyl nitrite, our practice implemented a repetitive squat-to-stand maneuver as an adjunct to the Valsalva maneuver when assessing for LVOT obstruction. We sought to evaluate the efficacy of this repetitive squat-to-stand maneuver in eliciting LVOT obstruction compared with the Valsalva maneuver in a retrospective study.

Double-chambered right ventricle in adults: Invasive and noninvasive hemodynamic considerations

BackgroundData on the features of double-chambered right ventricular (DCRV) in adults are limited. It is also unclear how invasive and Doppler-derived assessments of right ventricular (RV) obstruction in DCRV correlate. MethodsRetrospective review of 17 adults (age ≥18 years) diagnosed with DCRV who underwent right heart catheterization at Mayo Clinic, MN between 1990 and 2021. Clinical, echocardiographic, and invasive hemodynamics were abstracted from the medical charts. ResultsMean age was 44 ± 19 years and 7 (41%) patients were female. Two patients (12%) had undergone prior surgical repair of DCRV with ventricular septal defect (VSD) closure and had residual/recurrent obstruction; a VSD had been previously documented in 16 patients (94%). RV inflow to pulmonary artery systolic gradient at catheterization was 42 (19; 95) mmHg. The correlation coefficient between RV inflow to pulmonary artery systolic gradients and Doppler-derived peak gradients was 0.87 (p < 0.0001); the coefficient between the RV inflow to pulmonary artery systolic gradients and Doppler-derived systolic mean gradients was 0.85. Doppler-derived maximum instantaneous gradients were significantly higher than directly measured values (p = 0.002) while no difference was seen when invasive gradients were compared to Doppler-derived systolic mean gradients (p = 0.16). There was no association between New York Heart Association functional class III/IV, presence of dyspnea or syncope/pre-syncope and invasively measured RV gradients. ConclusionSignificant discrepancy between non-simultaneous echo-derived and invasively measured intracavitary RV gradients was seen in adults with DCRV. There was no correlation between the degree of RV obstruction and symptoms/functional capacity.

Left Ventricular Outflow Tract Gradient Is Associated With Coronary Artery Obstruction in Children With Williams-Beuren Syndrome

Patients with Williams-Beuren syndrome are associated with a high risk of hemodynamic collapse during sedation and/or anesthesia, presumably due to occult coronary obstruction. The objective of this study was to determine the association between transthoracic echocardiogram findings and the presence of coronary obstruction to examine if coronary obstruction can be predicted by transthoracic echocardiogram before anesthesia. Retrospective data analysis of patients with Williams-Beuren syndrome who underwent transthoracic echocardiogram, cardiac catheterization, and/or surgical interventions to determine the correlation between echocardiogram findings and the presence of coronary obstruction determined by cardiac catheterization and/or surgery. Single-center university teaching hospital. The study included 49 patients with Williams-Beuren syndrome who underwent transthoracic echocardiogram, cardiac catheterization, and/or surgical interventions. The only variable associated with coronary artery obstruction was the maximum instantaneous gradient (MIG) across the left ventricular outflow tract (LVOT) on a transthoracic echocardiogram. LVOT MIG ≥ 75 mmHg as the optimal cutoff value was associated with coronary artery obstruction (area under the curve 0.659, odds ratio 6.71, 95% CI 1.31-34.35, p = 0.022). LVOT gradient can serve as a good predictor of the presence of coronary obstruction in patients with Williams-Beuren syndrome.

P339 Gradient adjusted cardiac power index does not improve prediction of survival post transcatheter aortic valve replacement compared to cardiac power index alone

Abstract Funding Acknowledgements None Background Cardiac Power Index (CPI) is an integrative hemodynamic measure of cardiac pumping capability and is the product of the simultaneously measured mean arterial pressure (MAP) and cardiac output (CO). In patients with aortic stenosis (AS), MAP is not reflective of mean systolic left ventricular (LV) pressure due to the transvalvular gradient. Non-invasive assessment of mean systolic LV pressure is challenging in severe aortic stenosis. CPI assessed using systemic MAP was previously shown to predict survival post transcatheter aortic valve replacement (TAVR). Purpose We evaluated the utility of a gradient adjusted CPI in predicting survival post TAVR compared to CPI alone Methods A retrospective study was performed including patients undergoing TAVR with 1 year follow-up. Baseline demographics, clinical, and echocardiographic data were abstracted from a cohort of 1,011 patients. CPI was calculated, (CO x MAP)/ (451 x BSA) Watts/m2. Gradient adjusted CPI was calculated using an augmented MAP i) adding aortic valve mean gradient(AVMG) to systolic blood pressure (CPI1); ii) adding aortic valve maximal instantaneous gradient to systolic blood pressure (CPI2) and iii) adding AVMG to MAP (CPI3). Patient survival score was calculated using a step up technique to identify the cut off value for CPI and gradient adjusted CPI to identify, where the maximum difference in mortality occurred. Multivariate cox-regression analysis was performed to adjust for baseline covariates. Receiver operator curves(ROC) for CPI and gradient adjusted CPI were calculated to predict survival post TAVR. Results The mortality rate at 1 yr was 16%. Mean age and AVMG of survivors was 81 +/- 9 yrs and 43 +/-14 mmHg vs 80 +/-9 yrs and 42 +/- 13 mmHg in the deceased group. Proportion of female patients was similar in both groups (p = 0.7). Patients in the deceased group at baseline had a higher prevalence of chronic lung disease, atrial fibrillation, heart failure within 2-weeks of procedure, higher STS-PROM score, lower serum albumin level, higher prevalence of moderate to severe tricuspid regurgitation, higher right ventricular systolic pressure and higher prevalence of dialysis. Both CPI and gradient adjusted CPI were independently associated with survival at 1 year. The area under ROC for CP, CP1, CP2 and CP3 were 0.67 (95% confidence interval [CI] 0.62 - 0.72), 0.65 (95% CI 0.60 – 0.70), 0.66 (95% CI 0.61 – 0.71) and 0.63 (95% CI 0.58 – 0.68) respectively. Conclusion Gradient adjusted CPI did not improve accuracy of predicting post TAVR survival at 1 year compared to CPI alone. Abstract P339 Figure. Area under ROC

Does a Gradient-Adjusted Cardiac Power Index Improve Prediction of Post-Transcatheter Aortic Valve Replacement Survival Over Cardiac Power Index?

PurposeCardiac power (CP) index is a product of mean arterial pressure (MAP) and cardiac output (CO). In aortic stenosis, however, MAP is not reflective of true left ventricular (LV) afterload. We evaluated the utility of a gradient-adjusted CP (GCP) index in predicting survival after transcatheter aortic valve replacement (TAVR), compared to CP alone.Materials and MethodsWe included 975 patients who underwent TAVR with 1 year of follow-up. CP was calculated as (CO×MAP)/[451×body surface area (BSA)] (W/m2). GCP was calculated using augmented MAP by adding aortic valve mean gradient (AVMG) to systolic blood pressure (CP1), adding aortic valve maximal instantaneous gradient to systolic blood pressure (CP2), and adding AVMG to MAP (CP3). A multivariate Cox regression analysis was performed adjusting for baseline covariates. Receiver operator curves (ROC) for CP and GCP were calculated to predict survival after TAVR.ResultsThe mortality rate at 1 year was 16%. The mean age and AVMG of the survivors were 81±9 years and 43±4 mm Hg versus 80±9 years and 42±13 mm Hg in the deceased group. The proportions of female patients were similar in both groups (p=0.7). Both CP and GCP were independently associated with survival at 1 year. The area under ROCs for CP, CP1, CP2, and CP3 were 0.67 [95% confidence interval (CI), 0.62–0.72], 0.65 (95% CI, 0.60–0.70), 0.66 (95% CI, 0.61–0.71), and 0.63 (95% CI 0.58–0.68), respectively.ConclusionGCP did not improve the accuracy of predicting survival post TAVR at 1 year, compared to CP alone.

Use and performance of the Melody Transcatheter Pulmonary Valve in native and postsurgical, nonconduit right ventricular outflow tracts.

Melody Transcatheter Pulmonary Valve (TPV) replacement therapy represents an important advance in congenital cardiovascular interventions. The off-label extension of the Melody TPV to patients with nonconduit outflow tracts (right ventricular outflow tract [RVOT]) has the potential to vastly expand the population of patients eligible to benefit from nonsurgical restoration of RVOT function. However, knowledge on the performance of the Melody TPV in this setting is limited. This is a multicenter, retrospective review of the Melody TPV when placed in nonconduit RVOTs, in which at least a portion of the circumference was composed of native tissue. Five centers contributed data on 31 patients. The median age at implantation was 24 years (range, 7-66). At a median follow-up of 15 months, all patients were alive. No patient had greater than mild TPV insufficiency, and the median maximum instantaneous gradients across the RVOT was 23 mm Hg. Stent fracture occurred in 32%. Eight patients developed more than mild TPV obstruction, of whom 6 were associated with identified stent fracture. Three patients developed blood stream infections. There were 5 reinterventions in 3 patients, including 3 repeat TPV implantations and 2 TPV explantations. Melody TPV implantation is feasible in selected patients with RVOTs comprised solely or predominantly native tissue and has the potential to expand the population of patients eligible to benefit from nonsurgical restoration of RVOT function. In early follow-up, valve competency seems preserved. The dominant mechanism of valve dysfunction seems to be related to stent fracture with recurrent obstruction. Additional data are necessary to better understand how to safely expand TPV therapy to this population.

Outcome of Septal Myectomy for Obstructive Hypertrophic Cardiomyopathy in Children and Young Adults

Obstructive hypertrophic cardiomyopathy (HCM) is an important cause of heart failure in children, but there are limited data addressing outcome of myectomy in children. Our objective was to evaluate the early and late results of septal myectomy in pediatric HCM. We reviewed 127 consecutive patients (62% male) who underwent transaortic septal myectomy for obstructive HCM from January 1975 to December 2010 at 21 or less years of age. Mean age at operation was 12.9 ± 5.5 years. Preoperatively, mean maximum instantaneous gradient was 89 mm Hg and 95% had significant systolic anterior motion (SAM) with mitral regurgitation (MR). Implantable cardioverter defibrillator (ICD) and permanent pacemaker prior to surgery was present in 21 patients (17%) and 15 (11.7%), respectively. Transaortic extended left ventricular septal myectomy was performed in all patients with no early deaths. Iatrogenic morbidity included new aortic valve regurgitation requiring repair in 7 (5.5%), mitral regurgitation needing repair in 2 (1.5%), ventricular septal defect in 1 (1%), and heart block requiring permanent pacemaker in 1 (1%). An ICD was implanted postoperatively in 8 during the same hospital admission. Mean MIG decreased from 89 to 6 mm Hg (p < 0.0001). Postoperatively, residual chordal SAM was present in 23% with mild or no MR; moderate MR was detected in 1 patient. Four patients (3%) died late during the mean follow-up period of 8.3 years (maximum, 37 years); 1 death was sudden. Overall survival was 98.6%, 94.9%, 92.4%, and 92.4% at 5, 10, 15, and 20 years, respectively. Freedom from any cardiac reoperation was 91.2%, 87.8%, 78.7%, and 72.7% at 5, 10, 15, and 20 years, respectively. Repeat septal myectomy was performed in 6 patients (5%). At late follow-up, 95% were in New York Heart Association functional class I or II and 25 patients underwent late ICD placement. Septal myectomy is safe and effective in children with obstructive HCM, but limited exposure may increase risk of aortic or mitral valve injury. Late survival is better than the previously published untreated natural history of HCM. Patient selection and surgical expertise remain critical components of septal myectomy, especially before considering a prophylactic myectomy in a seemingly asymptomatic patient.

Abstract 17306: Right Ventricular Response to Exercise in Patients with an Obstructed Right Ventricle-to-Pulmonary Artery Conduit: Effects of Transcatheter Pulmonary Valve Replacement

Background: In patients with repaired congenital heart disease, the clinical evaluation of right ventricular outflow tract (RVOT) conduit dysfunction (i.e. stenosis or regurgitation) has classically involved analysis of anatomic and physiologic changes of the right ventricle (RV) at rest. Such evaluation does not reflect dynamic changes that occur during exercise, or elicit functional changes in response to physiologic stress. In this study, we characterized the physiologic effects of exercise on the RV in patients with an obstructed RVOT conduit before and after transcatheter pulmonary valve replacement (TPV). Methods: Patients with RVOT conduit obstruction who underwent TPV between March 2010- March 2011 at Children's Hospital Boston were enrolled. Exercise echocardiograms were performed in all patients. Rest and peak exercise RVOT gradient, RV systolic pressure, and 2D global longitudinal RV strain parameters (composite of 6-segment RV strain from a 4-chamber apical view via speckled tracking) were obtained prior to and 6 months post-TPV. Results: A total of 12 patients, of whom 8 had Tetralogy of Fallot (67%) were enrolled and completed the study. Median age at the time of TPV was 18 yrs (range 4 - 28). Prior to TPV, the median resting maximum instantaneous gradient (MIG) was 60mmHg (range 32-85) and increased with peak exercise to 95 mmHg (range 50 -156; p&lt;0.001). At baseline, resting global RV strain was -15% (-6, 19.6) and increased to -17% (-3, -22; p =0.005) at peak exercise. Following TPV, median MIG declined significantly at rest to 21mmHg (range 16-41; p= 0.03 vs. pre-TPV) and at peak exercise, 41mmHg (range 27-81; p=0.03 vs. pre-TPV), but still with a significant increase in MIG from rest to peak exercise (p&lt;0.001). Following TPV, global RV strain increased at rest,-17% (-2, -24; p= 0.005), and further at peak exercise, -20% (-6, -23; p=0.01). Conclusions: Exercise led to a significant increase in the peak RVOT gradient and global longitudinal RV strain both before and after TPV. TPV resulted in significantly improved RVOT gradient and longitudinal RV myocardial deformation both at rest and during peak exercise.

Cutting balloon for the treatment of resistant pulmonic valve stenosis

Background: Congenital pulmonic valve stenosis comprises 7.5–9% of congenital heart defects. The treatment of choice is percutaneous balloon valvuloplasty; however, a small percentage of patients have thick and flexible valve leaflets (dysplastic valves) that require surgical valvotomy. We aim to report our experience using a cutting balloon and repeated balloon dilation as a last attempt before surgical referral. Methods: Between June 2005 and November 2010, we treated 50 patients with isolated pulmonic valve stenosis. Five patients (10%) had thick and dysplastic pulmonic valve leaflets that were resistant to repeated balloon dilation attempts. We attempted to create a tear in the dysplastic pulmonic valve by performing pulmonic valvotomy using a cutting balloon (Boston Scientific, Natick, MA, USA), which was advanced through a long sheath, followed by repeated standard balloon dilation. Results: There was no change in the peak systolic gradient at catheterization after conventional pulmonic valve balloon dilation. However, a reduction of 37% was observed, during catheterization, after cutting balloon dilation and additional standard balloon dilation (p = 0.09). Echocardiographic follow-up showed a 23% decrease of the maximum instantaneous gradient early after cutting balloon dilation of the pulmonic valve (from 75 ± 15 to 58 ± 4 mmHg, p = 0.05). There was no restenosis of the valve (50 ± 13 mmHg) at long-term 5.5 years ± 9 months follow-up (range 4.5–6 years) and no complications. Conclusion: The use of cutting balloon is a possible option for the treatment of resistant congenital pulmonic valve stenosis before referral for surgical valvotomy. A larger controlled trial is needed to assess the effectiveness and safety of the procedure and validate our experience in this small series.

Valsalva maneuver, uncontrolled hypertension, asymmetric septal hypertrophy and dynamic outflow obstruction: a case report

A 83-year-old woman presented with a 25-year history of hypertension which was long-standing, uncontrolled, severe hypertension because of irregular oral administration of antihypertensive drug underwent an echocardiographic examination as part of an evaluation of hypertension. She described chest distress associated with activity, syncope for three times in the past one year. On physical examination, she was in no acute distress, with a regular pulse rate and blood pressure of 185/115 mmHg. On auscultation, her lung fields were clear. There was a III/VI late peaking crescendo/decrescendo systolic murmur along the left sternal border radiating to the apex, which increased with standing and Valsalva's maneuver and decreased with squatting. There was no report of provocative maneuvers performed during auscultation. There was no edema. Transthoracic echocardiography showed a hyperdynamic left ventricle with markedly increased left ventricular wall thicknesses and asymmetrical septal hypertrophy. M-mode echocardiography showed systolic anterior motion of the mitral valve apparatus and midsystolic closure of the aortic valve. A dynamic left ventricular outflow tract obstruction was present, with a resting maximal instantaneous gradient of 55 mmHg. With the Valsalva maneuver, the gradient increased to 114 mmHg. No any factors that could cause hypertension were found at kidney, adrenal gland and renal artery etc. by ultrasound and multislice compute tomography.

Abdominal Aortic Pulsed Wave Doppler Patterns Reliably Reflect Clinical Severity in Patients with Coarctation of the Aorta

There are situations in which standard echocardiography does not adequately define the aortic arch. We sought to determine what additional information could be gained by analyzing abdominal aortic Doppler flows in coarctation. Previously recorded echocardiographic data were reviewed in 70 controls and 248 patients with coarctation, including abdominal aortic values for pulsatility indices, pulse delay, and presence of early diastolic reversal. Ability of these variables to distinguish controls from coarctation patients and to assess coarctation severity was assessed. Corrected maximum instantaneous gradient and all abdominal aortic flow variables were associated with severity of obstruction. Early diastolic reversal was universally absent in significant coarctation. Threshold values for other parameters associated with significant obstruction were: corrected pulse delay >or=3.4 msec(1/2), pulsatility index <2.0, and systolic to diastolic velocity ratio <3.6. A combined abdominal aortic "variable" (absence of early diastolic reversal and corrected pulse delay >or=2.8 msec(1/2)) was found to be the best predictor of clinical coarctation status (positive predictive value = 93%, negative predictive value = 88%). In the absence of a ductus arteriosus, abdominal aortic Doppler parameters can reliably predict the presence of significant coarctation. When early diastolic reversal was present, obstruction was always absent. Lack of early diastolic reversal with a prolonged pulse delay was the best predictor of significant obstruction. Abdominal aortic Doppler evaluation should become a routine part of the evaluation of patients with known or suspected coarctation.

Impact of Septal Myectomy on Left Atrial Volume and Left Ventricular Diastolic Filling Patterns: An Echocardiographic Study of Young Patients with Obstructive Hypertrophic Cardiomyopathy

Septal myectomy in young patients with obstructive hypertrophic cardiomyopathy (HCM) can be performed with low mortality, and leads to excellent improvement in symptoms. Left atrial (LA) enlargement has been associated with exercise intolerance, severity of mitral regurgitation (MR), and left ventricular (LV) outflow tract (LVOT) obstruction in adults with HCM. Young patients (1-22 years of age) who had a septal myectomy for obstructive HCM between 2002 and 2005 were identified. Retrospective analyses of premyectomy and postmyectomy echocardiograms were performed. In this cohort of 32 patients (25 male), the average maximal LV wall thickness was 25 +/- 9 mm and LVOT maximal instantaneous gradient was 106 +/- 44 mm Hg. MR was present in all patients with a mean grade of 3 +/- 1. All patients had successful myectomy and there were no early deaths. After myectomy, LVOT maximal instantaneous gradient decreased to 17 +/- 13 mm Hg (P < .0001). Mean LA volume (LAV) index decreased from 52.1 +/- 2.2 to 33.2 +/- 11.9 mL/m(2) (P < .0001). Mean MR grade decreased to 2 +/- 1. Early mitral medial annular tissue Doppler velocity (E') increased from 6.2 +/- 1.9 to 13 +/- 2.6 cm/s (P < .043). A postmyectomy decrease in LAV index correlated with decrease in LVOT obstruction (P = .001) and change in degree of MR (P = .04). Septal myectomy not only reduces LVOT maximal instantaneous gradient and MR in young patients, but also results in decreased LAV index, and E/A and E/E' ratios. These hemodynamic improvements may contribute to the observed survival benefit and increased exercise tolerance observed after myectomy. This is the first series to demonstrate that LAV correlates closely with hemodynamic status in children with obstructive HCM and may be a significant predictor of clinical outcome in these patients.

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.

Severe Stenosis of a Bovine Jugular Vein Graft in Pulmonary Position

The bovine jugular vein graft (Contegra, Medtronic Inc, Minneapolis, Minn) has been successfully used as vascular conduit for valve reconstruction in the last few years, generally in the pediatric population. Complications after implantation include thrombosis at the level of the conduit valve (especially in infants), pseudoaneurysm, and stenosis at the level of the distal anastomosis. A 29-year-old man presented with symptoms and signs of right-sided heart failure (ie, exercise intolerance, dyspnea, jugular vein distention, hepatomegaly, ascites, ankle edema). Two and a half years previously, he had undergone Ross procedure because of severe aortic regurgitation caused by intravenous drug abuse–related Staphylococcus aureus endocarditis. The 22-mm bovine jugular vein graft was implanted in pulmonary position. Transthoracic echocardiography revealed a severely stenotic graft at the distal anastomosis to the pulmonary trunk whereas the valve itself appeared normal (Figure 1, A). The supravalvular tissue overgrowth detected was suggestive of massive neointimal hyperplasia. Doppler analysis documented a maximal instantaneous systolic gradient of 105 mm Hg and a mean systolic gradient of 63 mm Hg (Figure 1, B) and color Doppler imaging confirmed flow acceleration at the level of the distal graft anastomosis (Figure 1, C). The patient underwent percutaneous balloon angioplasty and stent implantation (34-mm 8Zig Stent, Numed, Cornwall, Ontario, Canada). Transthoracic echocardiography performed the day of the procedure showed a well-expanded stent with a constant diameter across the graft (Figure 2, A). Doppler echocardiography documented a maximal instantaneous systolic gradient of 37 mm Hg and a mean systolic gradient of 23 mm Hg (Figure 2, B). The diastolic pressure gradient before the atrial contraction wave detected before stenting (Figure 1, B) vanished, indicating lowered

From Stem Cells to Viable Autologous Semilunar Heart Valve

An estimated 275,000 patients undergo heart valve replacement each year. However, existing solutions for valve replacement are complicated by the morbidity associated with lifelong anticoagulation of mechanical valves and the limited durability of bioprostheses. Recent advances in tissue engineering and our understanding of stem cell biology may provide a lifelong solution to these problems. Mesenchymal stem cells were isolated from ovine bone marrow and characterized by their morphology and antigen expression through immunocytochemistry, flow cytometry, and capacity to differentiate into multiple cell lineages. A biodegradable scaffold was developed and characterized by its tensile strength and stiffness as a function of time in cell-conditioned medium. Autologous semilunar heart valves were then created in vitro using mesenchymal stem cells and the biodegradable scaffold and were implanted into the pulmonary position of sheep on cardiopulmonary bypass. The valves were evaluated by echocardiography at implantation and after 4 months in vivo. Valves were explanted at 4 and 8 months and examined by histology and immunohistochemistry. Valves displayed a maximum instantaneous gradient of 17.2+/-1.33 mm Hg, a mean gradient of 9.7+/-1.3 mm Hg, an effective orifice area of 1.35+/-0.17 cm2, and trivial or mild regurgitation at implantation. Gradients changed little over 4 months of follow-up. Histology showed disposition of extracellular matrix and distribution of cell phenotypes in the engineered valves reminiscent of that in native pulmonary valves. Stem-cell tissue-engineered heart valves can be created from mesenchymal stem cells in combination with a biodegradable scaffold and function satisfactorily in vivo for periods of >4 months. Furthermore, such valves undergo extensive remodeling in vivo to resemble native heart valves.

Echocardiographic prediction of clinical outcome in medically treated patients with aortic stenosis

Background The onset of symptoms is crucial in the natural history of severe aortic stenosis. In contrast, the impact of the degree of valve obstruction and left ventricular dysfunction on clinical outcome in terms of progression of symptoms and mortality is undefined. Methods and Results Between April 1989 and June 1996, 108 patients (75% male, aged 68.7 ± 10.3 years) with pure and isolated aortic stenosis of at least moderate degree had a complete Doppler echocardiography. Left ventricular end-diastolic and end-systolic diameters, thickness of ventricular septum, mass and ejection fraction, and maximal instantaneous aortic gradient were measured. Patients were followed up through March 1999. Sixty-five patients who underwent aortic valve replacement were censored at the time of surgery. The end point was considered to be death or symptomatic progression (onset of new symptoms or worsening of symptoms). At the time of diagnosis 64 (59%) were in New York Heart Association (NYHA) class I-II and 44 (41%) in NYHA class III-IV. After a mean follow-up of 46 ± 21 months 6 patients died and 45 had worsening of symptoms. Univariate predictors of clinical outcome (death and worsening of symptoms) included left ventricular end-diastolic diameter (hazard ratio 1.03, P =.08), left ventricular end-systolic diameter (HR 1.04, P =.012), and left ventricular septum thickness (HR 1.14, P =.009) but not the degree of aortic obstruction. Multivariate predictors of clinical outcome were left ventricular septum thickness (P =.016) and left ventricular end-systolic diameter (P =.008). Conclusion In patients with various degrees of aortic stenosis the rate of clinical outcome is predicted by left ventricular function and septum thickness. Therefore both the left ventricular and aortic valve gradients should be taken into account when choosing the timing of intervention. (Am Heart J 2000;140:766-71.)

Significance of a cardiac murmur as the sole clinical sign in the newborn.

A cardiac murmur is a very common finding in the first few days of life. It is traditionally believed that lesions creating left-to-right shunts do not present so early. This study was aimed to define and to classify the causes of a murmur in a newborn with an otherwise normal examination. All echocardiograms performed on newborns aged 1-5 days who were referred for evaluation of a murmur in a 3-year period were reviewed. Newborns with additional clinical signs or antenatal diagnosis of a cardiac disease were excluded. Of 20,323 live births, there were 170 newborns referred for echocardiogram solely because of a murmur. Of these, 147 (86%) were found to have structural heart defects. The most common lesions found were those creating left-to-right shunts (66%). Ventricular septal defect was the most common single lesion (54/147, 37%), followed by patent ductus arteriosus (34 newborns, 23%). The combination of both was found in 10 newborns (7%). Six newborns (4%) had pulmonary valve stenosis and three (2%) aortic valve stenosis. Seven newborns (5%) had unforeseen complex heart disease. For five of them, delayed diagnosis would have resulted in potentially life-threatening conditions. There was no correlation between the category of lesion and the age of presentation. The audible threshold of a murmur correlated with a maximum instantaneous gradient of 25 mm Hg (range 11-46 mm Hg). Thirteen percent of newborns with isolated heart murmur had no identifiable structural heart disease. These data suggest that most asymptomatic newborns presenting with a murmur in the first days of life have structural heart disease. Some of the more serious defects would not have been diagnosed without early echocardiography. A left-to-right shunt, particularly a ventricular septal defect, may cause a murmur even the first day of life and is probably more common that has been acknowledged.

Operação de Ross: a intervenção ideal para pacientes aórticos jovens?

Fundamentos: Próteses valvares aórticas com desempenho hemodinâmico adequado possibilitariam maior regressão da hipertrofia ventricular e normalização da função ventricular. Isto possivelmente tenha implicações importantes no prognóstico tardio após a substituição da valva aórtica. Objetivo: Avaliar o desempenho hemodinâmico do auto-enxerto pulmonar em posição aórtica e a regressão da hipertrofia ventricular esquerda após a operação de Ross. Casuística e Métodos: De maio/95 a março/97, 45 pacientes com média de idades de 27,1 anos foram submetidos à operação de Ross. Todos os pacientes foram submetidos, no pós-operatório imediato, a ecocardiografia com Doppler e cateterismo cardíaco para avaliação do desempenho hemodinâmico dos auto e homoenxertos, assim como da massa e função ventricular esquerda. Catorze pacientes com evolução superior a seis meses submeteram-se a ecocardiografia de stress com dobutamina, para estudar o desempenho hemodinâmico dos auto e homoenxertos em condição de exercício. Resultados: A mortalidade hospitalar foi de 6%. Após tempo médio de seguimento de 12,8 meses (1-23), ocorreu um óbito súbito tardio e nenhuma complicação relacionada à prótese. O desempenho hemodinâmico imediato e tardio dos auto-enxertos foi praticamente normal, com média de gradiente médio de 1,8 ± 0,6 mmHg e média de gradiente instantâneo máximo de 2,9 ± 0,9 mmHg. O grau de insuficiência valvar foi desprezível. Mesmo em condição de exercício, os gradientes não se elevaram de forma significativa, com média de gradiente médio de 4,3 ± 2,5 mmHg e média de gradiente instantâneo máximo de 10,4 ± 6,1 mmHg. Os homoenxertos utilizados para a reconstrução da via de saída do ventrículo direito tiveram excelente desempenho hemodinâmico imediato; entretanto, no seguimento tardio apresentaram discreto aumento das velocidades de fluxo com média de gradiente médio de 10 ± 7,1 mmHg em repouso e 26 ± 13,3 mmHg durante o exercício. O índice de massa ventricular esquerda caiu de 168 ± 46g/m² no pré-operatório para 115 ± 32g/m² no 6º mês de evolução. A função ventricular esquerda apresentou-se normal em repouso e no exercício na maioria dos pacientes. Conclusões: Dado o desempenho hemodinâmico normal dos auto-enxertos pulmonares, a redução da massa ventricular e normalização da função do ventrículo esquerdo, além da ótima evolução tardia dos pacientes, consideramos a operação de Ross como a operação ideal para pacientes aórticos jovens.

Transvascular Balloon Dilation for Neonatal Critical Aortic Stenosis: Early and Midterm Results

Objectives. We evaluated our immediate and midterm (mean 4.3 years) results of balloon dilation of critical valvular aortic stenosis in 33 neonates.Background. Balloon dilation has been used as an alternative to surgical treatment. Reports to date consist of small series (largest 16 babies) with short-term follow-up (longest 4.8 years).Methods. From 1985 to 1991, 33 neonates had dilation at a mean age of 13 days and a mean weight of 3.4 kg. Nineteen of the neonates (58%) were intubated and received prostaglandins, and 94% had other cardiac abnormalities.Results. The dilation was completed retrograde in 31 of the neonates (umbilical artery in 11 and femoral artery in 20) and anterograde (femoral vein) in 2. The average immediate peak gradient and left ventricular end-diastolic pressure reductions were 54% and 20%, respectively. The overall mortality rate was 12% (three early deaths and one late). All 20 neonates dilated through a femoral artery initially had pulse loss with restoration in 35% after thrombolytic therapy. At 8.3 years, survival and freedom of reintervention probability rates were 88% and 64%, respectively. At mean 4.3 years of follow-up, 83% of the survivors were asymptomatic; Doppler study revealed a maximal instantaneous gradient <50 mm Hg in 65% of neonates and significant aortic regurgitation in 14%.Conclusions. This study confirms that dilation of aortic stenosis in neonates is effective; reintervention (mostly redilation) is frequent (40%); and midterm survival is encouraging (88%).(J Am Coll Cardiol 1997;29:442–7)