A clinical and echocardiographic score for assigning risk of major events after dobutamine echocardiograms

OBJECTIVES We sought to develop and validate a risk score combining both clinical and dobutamine echocardiographic (DbE) features in 4,890 patients who underwent DbE at three expert laboratories and were followed for death or myocardial infarction for up to five years. BACKGROUND In contrast to exercise scores, no score exists to combine clinical, stress, and echocardiographic findings with DbE. METHODS Dobutamine echocardiography was performed for evaluation of known or suspected coronary artery disease in 3,156 patients at two sites in the U.S. After exclusion of patients with incomplete follow-up, 1,456 DbEs were randomly selected to develop a multivariate model for prediction of events. After simplification of each model for clinical use, the models were internally validated in the remaining DbE patients in the same series and externally validated in 1,733 patients in an independent series. RESULTS The following score was derived from regression models in the modeling group (160 events): DbE risk = (age (.) 0.02) + (heart failure + rate-pressure product <15,000) (.) 0.4 + (ischemia + scar) (.) 0.6. The presence of each variable was scored as 1 and its absence scored as 0, except for age (continuous variable). Using cutoff values of 1.2 and 2.6, patients were classified into groups with five-year event-free survivals >95%, 75% to 95%, and <75%. Application of the score in the internal validation group (265 events) gave equivalent results, as did its application in the external validation group (494 events, C index = 0.72). CONCLUSIONS A risk score based on clinical and echocardiographic data may be used to quantify the risk of events in patients undergoing DbE. (C) 2004 by the American College of Cardiology Foundation.

Echocardiographic detection of early diabetic myocardial disease

OBJECTIVES We sought to determine whether disturbances of myocardial contractility and reflectivity could be detected in diabetic patients without overt heart disease and whether these changes were independent and incremental to left ventricular hypertrophy (LVH). BACKGROUND Left ventricular (LV) dysfunction is associated with diabetes mellitus, but LVH is common in this population and the relationship between diabetic LV dysfunction and LVH is unclear. METHODS We studied 186 patients with normal ejection fraction and no evidence of CAD: 48 with diabetes mellitus only (DM group), 45 with LVH only (LVH group), 45 with both diabetes and LVH (DH group), and 48 normal controls. Peak strain and strain rate of six walls in apical four-chamber, long-axis, and two-chamber views were evaluated and averaged for each patient. Calibrated integrated backscatter (113) was assessed by comparison of the septal or posterior wall with pericardial IB intensity. RESULTS All patient groups (DM, DH, LVH) showed reduced systolic function compared with controls, evidenced by lower peak strain (p < 0.001) and strain rate (p = 0.005). Calibrated 113, signifying myocardial reflectivity, was greater in each patient group than in controls (p < 0.05). Peak strain and strain rate were significantly lower in the DH group than in those in the DM alone (p < 0.03) or LVH alone (p = 0.01) groups. CONCLUSIONS Diabetic patients without overt heart disease demonstrate evidence of systolic dysfunction and increased myocardial reflectivity. Although these changes are similar to those caused by LVH, they are independent and incremental to the effects of LVH. (C) 2003 by the American College of Cardiology Foundation.

Reproducibility and accuracy of echocardiographic measurements of left ventricular parameters using real-time three-dimensional echocardiography

OBJECTIVES We sought to determine whether assessment of left ventricular (LV) function with real-time (RT) three-dimensional echocardiography (3DE) could reduce the variation of sequential LV measurements and provide greater accuracy than two-dimensional echocardiography (2DE). BACKGROUND Real-time 3DE has become feasible as a standard clinical tool, but its accuracy for LV assessment has not been validated. METHODS Unselected patients (n = 50; 41 men; age, 64 +/- 8 years) presenting for evaluation of LV function were studied with 2DE and RT-3DE. Test-retest variation was performed by a complete restudy by a separate sonographer within 1 h without alteration of hemodynamics or therapy. Magnetic resonance imaging (MRI) images were obtained during a breath-hold, and measurements were made off-line. RESULTS The test-retest variation showed similar measurements for volumes but wider scatter of LV mass measurements with M-mode and 2DE than 3DE. The average MRI end-diastolic volume was 172 +/- 53 ml; LV volumes were underestimated by 2DE (mean difference, -54 +/- 33; p < 0.01) but only slightly by RT-3DE (-4 +/- 29; p = 0.31). Similarly, end-systolic volume by MRI (91 +/- 53 ml) was underestimated by 2DE (mean difference, -28 +/- 28; p < 0.01) and by RT-3DE (mean difference, -3 +/- 18; p = 0.23). Ejection fraction by MRI was similar by 2DE (p = 0.76) and RT-3DE (p = 0.74). Left ventricular mass (183 +/- 50 g) was overestimated by M-mode (mean difference, 68 +/- 86 g; p < 0.01) and 2DE (16 +/- 57; p = 0.04) but not RT-3DE (0 +/- 38 g; p = 0.94). There was good inter- and intra-observer correlation between RT-3DE by two sonographers for volumes, ejection fraction, and mass. CONCLUSIONS Real-time 3DE is a feasible approach to reduce test-retest variation of LV volume, ejection fraction, and mass measurements in follow-up LV assessment in daily practice. (C) 2004 by the American College of Cardiology Foundation.

Echocardiographic parameters in 14 healthy English Bull Terriers

Objective To determine the range of various cardiac parameters using echocardiography in apparently normal, healthy English Bull Terriers. Design Fourteen English Bull Terriers were selected for study. Cardiac auscultation of the parents of these dogs was normal. Echocardiographic examination of one parent of each animal showed: no mitral or aortic valve abnormalities; no myocardial lesions; no two dimensional evidence of fixed or dynamic left ventricular outflow tract obstruction; and no systolic aortic or left ventricular outflow tract turbulence on colour flow Doppler examination. The 14 selected dogs did not have arrhythmias or murmurs, and on echocardiographic examination had similar findings to their parents. Systolic blood pressure was measured in all dogs and they had no clinical evidence of Bull Terrier polycystic kidney disease or Bull Terrier hereditary nephritis. Procedure All dogs were auscultated and subjected to a sequential global echocardiographic assessment of the heart, including two dimensional long and short axis, and colour flow Doppler interrogation of the mitral and aortic valves. Dimensional measurements, including those from the left atrium, aortic annulus and left ventricle, were taken from a right parasternal window, and derived values such as fractional shortening, stroke volume and left atrial to aortic annulus ratio were calculated. Peak systolic aortic velocity was measured from the left parasternal window using two dimensional-guided pulsed wave Doppler with angle correction. Systolic blood pressure was measured using a Doppler monitor. The absence of Bull Terrier polycystic kidney disease was determined using renal ultrasonography, and of Bull Terrier hereditary nephritis using urinary protein to creatinine ratio. Results These 14 dogs had greater left ventricular wall thickness and smaller aortic root diameters than those reported as normal for other breeds of comparable body size. Left atrial dimensions were also larger, however this may have been due to the maximising method of measurement. These apparently normal English Bull Terriers also had higher aortic velocities than those reported for other breeds, possibly due to a smaller aortic root diameter or other anatomic substrate of the left ventricular outflow tract, lower systemic vascular resistance, or breed-specific normal left ventricular hypertrophy. While these dogs were selected to be as close to normal as possible, the breed may have a particular anatomy that produces abnormal left ventricular echocardiographic parameters. Conclusion These echocardiographic parameters may be used to diagnose left ventricular outflow tract obstruction and left ventricular hypertrophy, and inaccurate diagnoses may result if breed-specific values are not used.

Use of real-time three-dimensional echocardiography to measure left atrial volume: Comparison with other echocardiographic techniques

Objectives: Left atrial (LA) volume (LAV) is a prognostically important biomarker for diastolic dysfunction, but its reproducibility on repeated testing is not well defined. LA assessment with 3-dimensional. (3D) echocardiography (3DE) has been validated against magnetic resonance imaging, and we sought to assess whether this was superior to existing measurements for sequential echocardiographic follow-up. Methods: Patients (n = 100; 81 men; age 56 +/- 14 years) presenting for LA evaluation were studied with M-mode (MM) echocardiography, 2-dimensional (2D) echocardiography, and 3DE. Test-retest variation was performed by a complete restudy by a separate sonographer within 1 hour without alteration of hemodynamics or therapy. In all, 20 patients were studied for interobserver and intraobserver variation. LAVs were calculated by using M-mode diameter and planimetered atrial area in the apical. 4-chamber view to calculate an assumed sphere, as were prolate ellipsoid, Simpson's biplane, and biplane area-length methods. All were compared with 3DE. Results: The average LAV was 72 +/- 27 mL by 3DE. There was significant underestimation of LAV by M-mode (35 +/- 20 mL, r = 0.66, P < .01). The 3DE and various 2D echocardiographic techniques were well correlated: LA planimetry (85 +/- 38 mL, r = 0.77, P < .01), prolate ellipsoid (73 +/- 36 mL, r = 0.73, P = .04), area-length (64 +/- 30 mL, r = 0.74, P < .01), and Simpson's biplane (69 +/- 31 mL, r = 0.78, P = .06). Test-retest variation for 3DE was most favorable (r = 0.98, P < .01), with the prolate ellipsoid method showing most variation. Interobserver agreement between measurements was best for 3DE (r = 0.99, P < .01), with M-mode the worst (r = 0.89, P < .01). Intraobserver results were similar to interobserver, the best correlation for 3DE (r = 0.99, P < .01), with LA planimetry the worst (r = 0.91, P < .01). Conclusions. The 2D measurements correlate closely with 3DE. Follow-up assessment in daily practice appears feasible and reliable with both 2D and 3D approaches.

Characteristics of left ventricular diastolic dysfunction in the community: an echocardiographic survey

Objective: To determine the prevalence and predictors of left ventricular (LV) diastolic dysfunction in older adults. Design, setting and participants: A cross-sectional survey of 1275 randomly selected residents of Canberra, aged 60 to 86 years (mean age 69.4; 50% men), conducted between February 2002 and June 2003. Main outcome measures: Prevalence of LV diastolic dysfunction as characterised by comprehensive Doppler echocardiography. Results: The prevalence of any diastolic dysfunction was 34.7% (95% CI 32.1% to 37.4%) and that of moderate to severe diastolic dysfunction was 7.3% (95% CI 5.9% to 8.9%). Of subjects with moderate to severe diastolic dysfunction, 77.4% had an LV ejection fraction (EF) > 50% and 76.3% were in a preclinical stage of disease. Predictors of diastolic dysfunction were higher age (p < 0.0001), reduced EF (p < 0.0001), obesity (p < 0.0001) and a history of hypertension (p < 0.0001), diabetes (p = 0.02) and myocardial infarction (p = 0.003). Moderate to severe diastolic dysfunction with normal EF, although predominantly preclinical, was independently associated with increased LV mass (p < 0.0001), left atrial volume (p < 0.0001), and circulating amino-terminal pro-B-type natriuretic peptide concentrations (p < 0.0001), and with decreased quality of life (p < 0.005). Conclusion: Diastolic dysfunction is common in the community and often unaccompanied by overt congestive heart failure. Despite the lack of symptoms, advanced diastolic dysfunction with normal EF is associated with reduced quality of life and structural abnormalities that reflect increased cardiovascular risk.

Development of a clinical and echocardiographic score for assigning risk of major events after exercise and dobutamine echocardiograms

The prognostic value of exercise (EXE) and dobutamine echocardiograms (DbE) has been well defined in large studies. However, while risk is determined by both clinical and echo features, no simple means of combining these data has been defined. We sought to combine these data into risk scores. Methods. At 3 expert centers, 7650 pts underwent standard EXE (n=5211) and DbE (w2439) for evaluation of known or suspected CAD and were followed for up to 10 years (mean 5-2) for major events (death or myocardial infarction). A subgroup of 2953 EXE and 1025 DbE pts was randomly selected to develop separate multivariate models for prediction of events. After simplication of each model for clinical use, models were validated in the remaining EXE and DbE pts. ResuI1s. The total number of events was 200 in the EXE and 225 in the DbE pts, of which 58 and 99 events occurred in the respective testing groups. The following regression equations gave equivalent results I” the testing and validation groups for both EXE and DbE; DbE = (Age’O.02) + (DM’l .O) + (Low RPP’0.6) + ([CHF+lschemia+Scar]‘O.7) EXE = ([DM+CHF]‘O.S) + O.S(lschemla #) + l.B(Scar#) - (METS0.19) (where each categorical variable scored 1 when present and 0 when absent, Ischemia# = 1 for l-2 VD. 6 for 3 VD; Scar# = 1 for 1-2 VD, 1.7 for 3 VD). The table summarizes the scores and equivalent outcomes for EXE and DbE. Conclusions. Risk scores based on clinical and EXE or DbE results may be used to quantify the risk of events during follow-up.

Radial artery pulse upstroke is not a good marker of left ventricular dysfunction: A comparison of radial tonometry, angiographic and echocardiographic measures of dP/dt

The first derivative of pressure over time (dP/dt) is a marker of left ventricular (LV) systolic function that can be assessed during cardiac catheterization and echocardiography. Radial artery dP/dt (Radial-dP/dt) has been proposed as a possible marker of LV systolic function (Nichols & O’Rourke, McDonald’s Blood Flow in Arteries) and we sought to test this hypothesis. Methods:We compared simultaneously recorded RadialdP/ dt (by high-fidelity tonometry) with LV-dP/dt (by highfidelity catheter and echocardiography parameters analogous to LV-dP/dt) in patients without aortic valve disease. In study 1, beat to beat Radial-dP/dt and LV-dP/dt were recorded at rest and during supine exercise in 12 males (aged 61±12 years) undergoing cardiac catheterization. In study 2, 2D-echocardiography and Radial-dP/dt were recorded in 59 patients (43 men; aged 64±10 years) at baseline and peak dobutamine-induced stress. Three measures at the basal septum were taken as being analogous to LV-dP/dt: (1) peak systolic strain rate, (2) strain rate (SR-dP/dt), and (3) tissue velocity during isovolumic contraction. Results: Study 1; there was a significant difference between resting LV-dP/dt (1461±383 mmHg/s) and Radial-dP/dt (1182±319 mmHg/s; P < 0.001), and a poor, but statistically significant, correlation between the variables (R2 = 0.006; P < 0.001) due to the high number of data points compared (n = 681). Similar results were observed during exercise. Study 2; there was a moderate association between baseline Radial-dP/dt and SRdP/ dt (R2 =−0.17; P < 0.01), but no significant relationship between Radial-dP/dt and all other echocardiographic measures analogous to LV-dP/dt at rest or peak stress (P > 0.05). Conclusion: The radial pressurewaveform is not a reliable marker of LV contractility.