Prognostic importance of the transmitral pressure gradient in mitral annular calcification with associated mitral valve dysfunction.

AIMS: The aim of this study was to define the natural history of patients with mitral annular calcification (MAC)-related mitral valve dysfunction and to assess the prognostic importance of mean transmitral pressure gradient (MG) and impact of concomitant mitral regurgitation (MR). METHODS AND RESULTS: The institutional echocardiography database was examined from 2001 to 2019 for all patients with MAC and MG ≥3 mmHg. A total of 5754 patients were stratified by MG in low (3-5 mmHg, n = 3927), mid (5-10 mmHg, n = 1476), and high (≥10 mmHg, n = 351) gradient. The mean age was 78 ± 11 years, and 67% were female. MR was none/trace in 32%, mild in 42%, moderate in 23%, and severe in 3%. Primary outcome was all-cause mortality, and outcome models were adjusted for age, sex, and MAC-related risk factors (hypertension, diabetes, coronary artery disease, chronic kidney disease). Survival at 1, 5, and 10 years was 77%, 42%, and 18% in the low-gradient group; 73%, 38%, and 17% in the mid-gradient group; and 67%, 25%, and 11% in the high-gradient group, respectively (log-rank P < 0.001 between groups). MG was independently associated with mortality (adjusted HR 1.064 per 1 mmHg increase, 95% CI 1.049-1.080). MR severity was associated with mortality at low gradients (P < 0.001) but not at higher gradients (P = 0.166 and 0.372 in the mid- and high-gradient groups, respectively). CONCLUSION: In MAC-related mitral valve dysfunction, mean transmitral gradient is associated with increased mortality after adjustment for age, sex, and MAC-related risk factors. Concomitant MR is associated with excess mortality in low-gradient ranges (3-5 mmHg) but gradually loses prognostic importance at higher gradients, indicating prognostic utility of transmitral gradient in MAC regardless of MR severity.

The echo score revisited: Impact of incorporating commissural morphology and leaflet displacement to the prediction of outcome for patients undergoing percutaneous mitral valvuloplasty.

BACKGROUND: Current echocardiographic scoring systems for percutaneous mitral valvuloplasty (PMV) have limitations. This study examined new, more quantitative methods for assessing valvular involvement and the combination of parameters that best predicts immediate and long-term outcome after PMV. METHODS AND RESULTS: Two cohorts (derivation n=204 and validation n=121) of patients with symptomatic mitral stenosis undergoing PMV were studied. Mitral valve morphology was assessed by using both the conventional Wilkins qualitative parameters and novel quantitative parameters, including the ratio between the commissural areas and the maximal excursion of the leaflets from the annulus in diastole. Independent predictors of outcome were assigned a points value proportional to their regression coefficients: mitral valve area ≤1 cm(2) (2), maximum leaflets displacement ≤12 mm (3), commissural area ratio ≥1.25 (3), and subvalvular involvement (3). Three risk groups were defined: low (score of 0-3), intermediate (score of 5), and high (score of 6-11) with observed suboptimal PMV results of 16.9%, 56.3%, and 73.8%, respectively. The use of the same scoring system in the validation cohort yielded suboptimal PMV results of 11.8%, 72.7%, and 87.5% in the low-, intermediate-, and high-risk groups, respectively. The model improved risk classification in comparison with the Wilkins score (net reclassification improvement 45.2%; P<0.0001). Long-term outcome was predicted by age and postprocedural variables, including mitral regurgitation, mean gradient, and pulmonary pressure. CONCLUSIONS: A scoring system incorporating new quantitative echocardiographic parameters more accurately predicts outcome following PMV than existing models. Long-term post-PMV event-free survival was predicted by age, degree of mitral regurgitation, and postprocedural hemodynamic data.

The impact of isometric handgrip testing on left ventricular twist mechanics.

Left ventricular (LV) rotation occurs due to contraction of obliquely oriented myocardial fibres. Left ventricular twist (LVT) results from rotation of the apex and base in opposite directions. Although LVT is altered in various cardiac diseases, physiological factors that affect LVT remain incompletely understood. Isometric handgrip testing (IHGT), a well-established laboratory-based technique to increase LV afterload, was performed for 3 min at 40% maximum force generation in healthy human subjects (n = 18, mean age 29.7 ± 2.7 years). Speckle-tracking echocardiography was used to measure LV volumes, LV apical and basal rotation, peak systolic LVT and peak early diastolic untwisting rate (UTR) at rest and at peak IHGT. IHGT led to significant increase in systemic blood pressure (systolic, 120.6 ± 9.7 vs. 155.6 ± 14.5 mmHg, P < 0.001; diastolic, 67.5 ± 6.4 vs. 94.1 ± 21.1 mmHg, P < 0.001) and LV end-systolic volume (44.2 ± 7.8 vs. 50.5 ± 10.8 ml, P = 0.005), as well as a significant increase in heart rate (62.8 ± 11.7 vs. 84.7 ± 13.8 beats min−1; P < 0.001). IHGT produced a significant acute reduction in LV stroke volume (63.9 ± 12.0 vs. 49.4 ± 7.8 ml, P < 0.001). In this setting, there was a significant decrease in peak systolic apical rotation (11.9 ± 3.0 vs. 8.6 ± 2.2 deg, P < 0.001) and a resultant 25% decrease in peak systolic LVT (16.6 ± 2.8 vs. 12.5 ± 2.8 deg, P < 0.001). The magnitude of peak early diastolic UTR did not change (−114.5 ± 26.4 vs. −110.6 ± 39.8 deg s−1, P = 0.71). Peak systolic apical rotation and LVT decrease during IHGT in healthy humans. This impairment of LV twist mechanics may in part underlie the LV dysfunction that can occur in the clinical context of acute increase in afterload.

Future directions in echocardiography.

Future developments in echocardiography will likely focus on the continued evolution of existing techniques, such as real-time 3-dimensional (RT3D) imaging and contrast-enhanced imaging; higher resolution imaging; and greater flexibility in imaging systems due to miniaturization, enhanced connectivity, and integration with other techniques. Improvements in RT3D image quality may include expanded parallel processing and use of transesophageal matrix arrays. Two areas of future clinical potential for contrast-enhanced echocardiography/ultrasound are the use of targeted microbubbles for diagnostic and therapeutic applications and expanded vascular imaging. Although molecular imaging holds great promise for the future, in the short-term, it is likely that contrast will be used more extensively for vascular imaging to assess both the effects of interventions on local perfusion and the activity of atherosclerotic plaque based on the size/density of the vasa vasorum. The widespread use of ultrasound will be facilitated by the development of a convenient portable or readily available ultrasonic equivalent of the stethoscope.

Derivation of a size-independent variable for scaling of cardiac dimensions in a normal paediatric population.

AIMS: It is general practice to correct cardiac chamber size for body size by the process of scaling or normalization. Normalization is most commonly performed using simple linear or isometric correction; however, there is increasing evidence that this approach may be flawed. Likewise, there is little agreement concerning the appropriate scaling variable (measure of body size) for normalization. Therefore, we aimed to establish the optimal method for correcting the differences in body size in a large population of echocardiographically normal paediatric subjects. METHODS AND RESULTS: We compared the relative ability of standard size variables including height (HT), body weight (BW), body mass index (BMI), and body surface area (BSA), in both isometric and allometric models, to remove the effect of body size in 4109 consecutive echocardiographically normal subjects<18 years of age, using the left atrial dimension (LAD) as a reference standard. Simple linear normalization resulted in significant residual correlations (r=-0.57 to -0.92) of the indexed value with the body size variable, the correlations with weight (WT) and BSA actually increasing. In contrast, correction by the optimal allometric exponent (AE) removed the effects of the indexed variable (residual correlations -0.01 to 0.01), with BW and BSA best removing the effects of all the measures of body size. CONCLUSION: Conventional linear correction for body size is inaccurate in children and paradoxically increases the relationship of the indexed parameter with WT and BSA. Conversely, correction using the optimal AE removes the effect of that variable, with WT best correction for all measures of body size.

Mitral valve prolapse in Marfan syndrome: an old topic revisited.

BACKGROUND: The echocardiographic features of mitral valve prolapse (MVP) in Marfan syndrome have been well described, and the incidence of MVP in Marfan syndrome is reported to be 40-80%. However, most of the original research was performed in the late 1980s and early 1990s, when the diagnostic criteria for MVP were less specific. Our goal was to investigate the characteristics of MVP associated with Marfan syndrome using currently accepted diagnostic criteria for MVP. METHODS: Between January 1990 and March 2004, 90 patients with definitive diagnosis of Marfan syndrome (based on standardized criteria with or without genetic testing) were referred to Massachusetts General Hospital for transthoracic echocardiography. Patients' gender, age, weight, height, and body surface area at initial examination were recorded. Mitral valve thickness and motion, the degree of mitral regurgitation and aortic regurgitation, and aortic dimensions were quantified blinded to patients' clinical information. RESULTS: There were 25 patients (28%) with MVP, among whom 80% had symmetrical bileaflet MVP. Patients with MVP had thicker mitral leaflets (5.0 +/- 1.0 mm vs. 1.8 +/- 0.5 mm, P < 0.001), more mitral regurgitation (using a scale of 1-4, 2.2 +/- 1.0 vs. 0.90 +/- 0.60, P < 0.0001), larger LVEDD, and larger dimensions of sinus of Valsalva, sinotubular junction, aortic arch, and descending aorta indexed to square root body surface area, when compared with those without MVP. When echocardiographic features of patients younger than 18 years of age and those of patients older than 18 were compared, adult Marfan patients had larger LA dimension (indexed to square root body surface area), larger sinotubular junction (indexed to square root body surface area), and more mitral regurgitation and aortic regurgitation. CONCLUSIONS: The prevalence of MVP in Marfan syndrome is lower than previously reported. The large majority of patients with MVP have bileaflet involvement, and those with MVP have significantly larger aortic root diameters, suggesting a diffuse disease process.

Marfan syndrome and mitral valve prolapse.

Mitral valve prolapse (MVP), an abnormal displacement into the left atrium of a thickened and redundant mitral valve during systole, is a relatively frequent abnormality in humans and may be associated with serious complications. A recent study implicates fibrillin-1, a component of extracellular matrix microfibrils, in the pathogenesis of a murine model of MVP. This investigation represents an initial step toward understanding the mechanisms involved in human MVP disease and the development of potential treatments.

Infective endocarditis in the era of intracardiac devices: an echocardiographic perspective.

Although the role of echocardiography is well established in the management of native valve and prosthetic valve endocarditis, the recent introduction of intracardiac devices, including pacemakers, implantable defibrillators, closure devices, and ventricular assist devices, has expanded its utility. Echocardiography permits the direct imaging of valvular vegetations, and it allows for the identification of structural complications of endocarditis. It is useful for characterizing the hemodynamic consequences of the infection. It can also provide prognostic information concerning risk of embolization and/or need for cardiac surgery. This article reviews the roles of transthoracic echocardiography and transesophageal echocardiography in the evaluation of patients with native valve endocarditis, prosthetic valve endocarditis, and infections involving a variety of nonvalvular cardiovascular devices.

Which patients benefit from percutaneous mitral balloon valvuloplasty? Prevalvuloplasty and postvalvuloplasty variables that predict long-term outcome.

BACKGROUND: Percutaneous mitral balloon valvuloplasty (PMV) results in good immediate results, particularly in patients with echocardiographic scores (Echo-Sc) < or =8. However, which variables relate to long-term outcome is unclear. METHODS AND RESULTS: We report the immediate and long-term clinical follow-up (mean, 4.2+/-3.7 years; range, 0.5 to 15) of 879 patients who underwent 939 PMV procedures. Patients were divided into 2 groups, Echo-Sc < or =8 (n=601) and Echo-Sc >8 (n=278). PMV resulted in an increase in mitral valve area from 1.0+/-0.3 to 2.0+/-0.6 cm2 in patients with Echo-Sc < or =8 and from 0.8+/-0.3 to 1.6+/-0.6 cm2 in patients with Echo-Sc >8 (P<0.0001). Although adverse events (death, mitral valve surgery, and redo PMV) were low within the first 5 years of follow-up, a progressive number of events occurred beyond this period. Nevertheless, survival (82% versus 57%) and event-free survival (38% versus 22%) at 12-year follow-up was greater in patients with Echo-Sc < or =8 (P<0.0001). Cox regression analysis identified post-PMV mitral regurgitation > or =3+, Echo-Sc >8, age, prior surgical commissurotomy, NYHA functional class IV, pre-PMV mitral regurgitation > or =2+, and higher post-PMV pulmonary artery pressure as independent predictors of combined events at long-term follow-up. CONCLUSIONS: The immediate and long-term outcome of patients undergoing PMV is multifactorial. The use of the Echo-Sc in conjunction with other clinical and morphological predictors of PMV outcome allows identification of patients who will obtain the best outcome from PMV.

Bedside quantification of atherosclerosis severity for cardiovascular risk stratification: a prospective cohort study.

OBJECTIVES: We sought to assess the ability of a new noninvasive method to quantify atherosclerosis severity and to examine its power to predict cardiovascular events. BACKGROUND: Drug prevention of cardiovascular events is effective but costly, leading to a debate about who should receive this treatment. Patient selection is often based on surrogate markers, but quantification of atherosclerosis severity is desirable. METHODS: Atherosclerosis severity was quantified by determination of specific aortic wall elastance in transthoracic echocardiography, applying the biomechanics of pulse wave propagation. After validating the method in 52 patients by measuring aortic plaque burden in transesophageal echo directly, another 336 patients were prospectively studied by monitoring atherosclerotic events at one year and comparing the results with conventional risk stratification. RESULTS: Specific aortic elastance was well correlated with plaque burden (p < 0.0001) and largely independent of confounding variables. Specific aortic elastance predicted the primary end point of "atherosclerotic death, myocardial infarction or stroke" at one year (p < 0.0002). Event rate at one year in the lowest specific elastance tertile was 1.8% (CI 0.0% to 4.3%), in the middle tertile 5.4% (CI 1.1% to 9.7%) and in the highest tertile 12.7% (CI 6.3% to 19%). Secondary end points supported these findings. Stepwise multivariate analysis identified specific aortic elastance, prior atherosclerotic events and left ventricular ejection fraction as independent risk predictors. Specific elastance was of incremental value to clinically identified variables. CONCLUSIONS: Bedside measurement of specific aortic elastance allows assessment of atherosclerosis severity. It predicts the risk for future atherosclerotic events beyond conventional risk factors, promising better targeting of pharmacologic prevention and improved cost effectiveness.

Aortic stenosis: physics and physiology--what do the numbers really mean?

Cardiac catheterization and Doppler echocardiography are two methods used to measure transvalvular gradients and valve area in the assessment of aortic stenosis severity. Although both approaches are based on the same hemodynamic concepts and report data using the same units of measure, each method measures pressure drop or gradient at a different place; hence they produce fundamentally different quantities. Likewise, cardiac catheterization formulas for valve area attempt to obtain the anatomic area whereas the Doppler continuity equation reports the area to which flow is constricted. To use these two methods appropriately, it is necessary to understand the underlying hemodynamic principles and the effects of the methods of measurement on the values obtained. This article examines these variables and shows how they affect the reported gradients and valve areas and how differences can affect clinical application.

Contrast-Enhanced Ultrasound: A Novel Noninvasive, Nonionizing Method for the Detection of Brown Adipose Tissue in Humans.

BACKGROUND: Brown adipose tissue (BAT) consumes glucose when it is activated by cold exposure, allowing its detection in humans by (18)F-fluorodeoxyglucose (FDG) positron emission tomography (PET) with computed tomography (CT). The investigators recently described a novel noninvasive and nonionizing imaging method to assess BAT in mice using contrast-enhanced ultrasound (CEUS). Here, they report the application of this method in healthy humans. METHODS: Thirteen healthy volunteers were recruited. CEUS was performed before and after cold exposure in all subjects using a continuous intravenous infusion of perflutren gas-filled lipid microbubbles and triggered imaging of the supraclavicular space. The first five subjects received microbubbles at a lower infusion rate than the subsequent eight subjects and were analyzed as a separate group. Blood flow was estimated as the product of the plateau (A) and the slope (ß) of microbubble replenishment curves. All underwent (18)F-FDG PET/CT after cold exposure. RESULTS: An increase in the acoustic signal was noted in the supraclavicular adipose tissue area with increasing triggering intervals in all subjects, demonstrating the presence of blood flow. The area imaged by CEUS colocalized with BAT, as detected by ¹8F-FDG PET/CT. In a cohort of eight subjects with an optimized CEUS protocol, CEUS-derived BAT blood flow increased with cold exposure compared with basal BAT blood flow in warm conditions (median Aß = 3.3 AU/s [interquartile range, 0.5-5.7 AU/s] vs 1.25 AU/s [interquartile range, 0.5-2.6 AU/s]; P = .02). Of these eight subjects, five had greater than twofold increases in blood flow after cold exposure; these responders had higher BAT activity measured by (18)F-FDG PET/CT (median maximal standardized uptake value, 2.25 [interquartile range, 1.53-4.57] vs 0.51 [interquartile range, 0.47-0.73]; P = .02). CONCLUSIONS: The present study demonstrates the feasibility of using CEUS as a noninvasive, nonionizing imaging modality in estimating BAT blood flow in young, healthy humans. CEUS may be a useful and scalable tool in the assessment of BAT and BAT-targeted therapies.

Major Cardiac Events and the Value of Echocardiographic Evaluation in Patients Receiving Anthracycline-Based Chemotherapy.

Anthracyclines are an important component of cancer treatments; however, their use is limited by the occurrence of cardiotoxicity. There are limited data on the occurrence of heart failure and the value of baseline and follow-up measurements of left ventricular (LV) ejection fraction (EF) in the current era. Therefore, the objectives of the present study were twofold: (1) to characterize the occurrence of and risk factors for major adverse cardiac events (MACEs: symptomatic heart failure and cardiac death) in a large contemporaneous population of adult patients treated with anthracyclines and (2) to test the value of LVEF and LV dimensions obtained using echocardiography in the prediction of MACE. Five thousand fifty-seven patients were studied, of whom 124 (2.4%) developed MACE. Of the total cohort, 2,285 patients had an available echocardiogram pre-chemotherapy. Patients with MACE were older (p <0.0001), predominantly men (p = 0.03), and with a higher incidence of cardiovascular risk factors and cardiac treatments. Patients with hematologic cancers had a higher incidence of cardiac events than patients with breast cancer (4.2% vs 0.7%, p <0.0001). Baseline LVEF, LVEF ≤5 points above the lower limits of normal, and LV internal diameter were predictive of the rate of occurrence of MACE. In conclusion, older patients with hematologic cancers and patients with a baseline LVEF ≤5 points above the lower limit of normal have higher incidence of MACE and should be closely monitored.

Mitral valve replacement for restenosis after repeat percutaneous mitral valvuloplasty.

Percutaneous mitral valvuloplasty (PMV) produces good results for symptomatic mitral stenosis or restenosis if valve morphology is suitable. However, complications such as atrial septal defect have severe hemodynamic effects, and repeat PMV is not always appropriate. The patient in this case had already undergone multiple PMVs and was a candidate for valve replacement.

Hypertrophic obstructive cardiomyopathy: mechanism of obstruction and response to therapy.

Hypertrophic cardiomyopathy is a primary, usually familial, disorder of heart muscle whose primary feature is muscular hypertrophy without recognized cause that encroaches on the ventricular chamber, reducing chamber area and volume. In roughly 25% of cases, there is associated obstruction to left ventricular outflow (hypertrophic obstructive cardiomyopathy [HOCM]). This article details the mechanism of obstruction in HOCM, focusing on obstruction at the mitral valve level, and reviews the pharmacologic and surgical therapies currently available. Mainstays of pharmacologic therapy include b-blockers, calcium channel blockers (verapamil in particular), and/or disopyramide. Surgical therapies include septal myotomy/myectomy, which has become the gold standard to which other therapies are compared, and mitral valve replacement. During the past 10 years, atrio-ventricular sequential pacing and alcohol septal ablation have been proposed as less invasive alternatives to surgery. A single, optimal therapy for patients with HOCM and refractory symptoms has not been established, and decisions regarding surgical versus noninvasive therapies need to be individualized based on functional status, comorbidities, local expertise in the surgical and nonsurgical techniques, and patient preference.

Echocardiographic evaluation of pulmonary artery pressure with clinical correlates in predominantly obese adults.

Pulmonary artery systolic pressure (PASP) was examined in relationship to age, body mass index (BMI), the effects of comorbid disease, and standard echocardiographic measurements of cardiac chamber size, left ventricular filling patterns, and left ventricular systolic function in 5 large cohorts presenting with a primary problem of obesity. For subjects with a measurable PASP, means (+/- SD) across cohorts for age ranged from 46.0 +/- 11.2 to 54.1 +/- 12.8 years, for BMI from 26.0 +/- 4.4 to 37.2 +/- 6.1 kg/m2, and PASP (n = 1515) from 29.9 +/- 7.7 to 33.8 +/- 7.8 mm Hg. PASP 30 mm Hg or greater occurred in 46% to 66% of subjects and 35 mm Hg or greater in 16% to 36%. Age and BMI were the most significant correlates of PASP. Increased PASP was also significantly associated with systemic hypertension and a history of cardiovascular disease. The mean PASP in obese individuals is higher than previously reported with nearly one third having a PASP of 35 mm Hg or greater. Clinical interpretation of PASP should include BMI, age, blood pressure, and presence of cardiovascular disease.

Effect of destructive pulse duration on the detection of myocardial perfusion in myocardial contrast echocardiography: In vitro and in vivo observations.

UNLABELLED: Myocardial perfusion is detected with contrast echocardiography by comparing a contrast-enhanced image with a baseline obtained before contrast injection (true baseline) or after myocardial bubble destruction after a high-power destructive pulse (postdestructive pulse baseline). Although it is assumed that all bubbles are destroyed by a destructive pulse insuring optimal contrast detection, this assumption has not been tested. In 18 participants we compared the videointensity (VI) differences among the contrast-enhanced image, the postdestructive pulse baseline, and the true baseline using both triggered high-mechanical index imaging and real-time imaging. VI difference was significantly greater for the true baseline with both techniques at all ventricular levels. The benefit of using a true baseline was less when the duration of the destructive pulse was increased. Similarly, we quantified VI in a flow phantom using continuous Optison (commercially available perfluoropropane-filled albumin microbubbles) (Amersham, Princeton, NJ) infusion and variable durations of destructive pulses. VI decreased with the duration of the destructive pulse and reached a plateau after a duration of 8 to 15 frames. The plateau reached after a long destructive pulse was dependent on flow rate and concentration and never reached a true baseline, unless concentration (<100 microL/L) and flow rate (<0.5 cm/s) were very low. IN CONCLUSION: (1) in clinical studies, the difference in VI between contrast-enhanced and baseline images is greater when true baseline is used; (2) the longer the destructive pulse, the closer the postdestructive pulse baseline to true baseline; and (3) this effect exists in all regions of the left ventricle.

Pulse inversion harmonic imaging improves endocardial border visualization in two-dimensional images: comparison with harmonic imaging.

Pulse inversion harmonic imaging (PIHI) is a new modality that increases the detection of harmonic echoes and myocardial contrast by cancelling linearly transmitted signals. We tested whether PIHI improved the detection of endocardial borders in noncontrast 2-dimensional echocardiography. We compared PIHI with tissue harmonic imaging (THI), which decreases linearly transmitted signals using filters. Fundamental mode (FM) was compared with THI and PIHI in 50 consecutive patients. The global and segmental endocardial visualization scores measured with FM were significantly improved by using either THI or PIHI. The improvement of the global score compared with FM was slightly higher using PIHI than THI, because of an improved visualization of the base and the anterior wall with the PIHI technique compared with THI. The ratio of myocardial-to-cavity signal was similarly increased from FM with THI and PIHI. PIHI, a new modality for detection of myocardial contrast, can also be used for endocardial border visualization. It provides an improvement relative to THI for specific regions of the endocardium.

Echocardiographic Assessment of Right Ventricular Volume and Function.

Echocardiographic evaluation of right ventricular volume and function has become a subject of growing interest with the increasing awareness of the important role of the right ventricle in the entire circulation. However, the anatomically complex and load-dependent shaped right ventricle shape is difficult to describe by a simple geometric figure and its volume and function are, therefore, difficult to assess in a simple manner. A number of echocardiographic methods for evaluating right ventricular volume and function have emerged; to date, however, their quantification remains a clinical challenge. The major goal is to develop a reproducible method that will allow for quantitative comparisons between patients or serially within a given patient. This discussion examines the available methods with specific attention to their reliability and limitations. Visual inspection or measurement of single plane indices is limited by their lack of standardization and failure to describe the entire right ventricle. Simpson's rule requires computer calculations and assumes an elliptic symmetry present in the left, but not the right ventricle. Application of the area-length method to the subcostal outflow tract and apical four-chamber views is a particularly practical current approach. Three-dimensional echo reconstruction, which eliminates the need for geometric assumptions and individual standardized views, although only in its infancy, promises to be the most accurate method for right ventricular volume calculation and in the future should emerge as the standard for research and many clinical applications.

The Björk-Shiley convexo-concave heart valve experience from the perspective of the supervisory panel.

The 20-year activities of a medical supervisory panel appointed under the terms of a settlement agreement of the Bowling v. Pfizer class action suit involving the Björk-Shiley convexo-concave (BSCC) heart valve are detailed. Of approximately 86,000 valves implanted, catastrophic failure of the valve was reported in 663 patients from 1978 to 2012. In 1994, a 7-member medical panel consisting of cardiologists, cardiovascular surgeons, epidemiologists, and a nontechnical chairman was appointed by the federal court. The panel collected clinical and manufacturing data, supported epidemiologic studies assessing risk factors for valve fracture, and developed guidelines for payment for explanting potentially defective valves in patients. Three sets of guidelines, based on comparisons of estimated risks of valve fracture versus risks of valve replacement surgery, were issued by the panel to help guide patients and their physicians in decisions about explanting valves. In addition, the panel supported research directed at identifying valves at risk for outlet strut fracture. The primary techniques evaluated included analyzing acoustic signals from the valves, imaging valves for potential cracks in the struts, and structural analyses of Björk-Shiley convexo-concave valves, but none proved applicable for large-scale surveillance of the patient population. The panel also became a patient advocate and acted as an intermediary between the manufacturer and the attorneys initiating the legal settlement. The panel's experiences may help inform future strategies for guideline development for other medical devices or procedures involving risk-benefit comparisons.