M. Bountioukos

Incremental Value of Exercise Technetium-99m Tetrofosmin Myocardial Perfusion Single-Photon Emission Computed Tomography for the Prediction of Cardiac Events

Technetium-99m (Tc-99m) tetrofosmin single-photon emission computed tomography (SPECT) is a useful alternative to thallium-201 scintigraphy for the assessment of myocardial perfusion. This study assessed the incremental value of exercise Tc-99m tetrofosmin SPECT for the prediction of cardiac events in patients with known or suspected coronary artery disease. Exercise Tc-99m tetrofosmin SPECT imaging was performed in 655 consecutive patients. Follow-up was successful in 648 patients (98.9%). Ten patients underwent early coronary revascularization and were excluded. End points were cardiac death, nonfatal infarction, and late (>60 days) coronary revascularization. An abnormal study was defined as the presence of fixed and/or reversible perfusion defects. A summed stress score (SSS) was derived to estimate the extent and severity of perfusion defects. An abnormal scan was detected in 344 patients (54%). During a mean follow-up period of 4 +/- 1.3 years, 56 patients (9%) died (22 cardiac deaths). Nonfatal myocardial infarction occurred in 19 patients (3%), and 89 patients (14%) underwent late coronary revascularization. An abnormal scan was an independent predictor of cardiac death (hazard ratio 3.5, confidence intervals [CI] 1.1 to 12.2) and provided incremental information over clinical and exercise test data (log-likelihood -133 to -125, p <0.05). The SSS provided incremental prognostic information over clinical data as well (log-likelihood -133 to -127, p <0.05) (hazard ratio 1.23, CI 1.10 to 1.38). An abnormal scan (hazard ratio 3.3, CI 1.1 to 12.2)) and the SSS (hazard ratio 1.25, CI 1.07 to 1.45)) were powerful independent predictors of the combined end point of any cardiac event. Thus, exercise Tc-99m tetrofosmin myocardial perfusion SPECT provides information incremental to clinical data for the prediction of cardiac events in patients with known or suspected coronary artery disease.

Repetitive dobutamine stress echocardiography for the prediction of anthracycline cardiotoxicity

AIMS To evaluate whether repetitive assessment of systolic and diastolic cardiac function by dobutamine stress echocardiography (DSE) can predict anthracycline cardiotoxicity. METHODS AND RESULTS Thirty-one patients (age, 57+/-13 years, 22 male) were studied before chemotherapy, with follow-ups during, at the end, and 6 months after chemotherapy. Left ventricular (LV) function was assessed by two-dimensional (2D) echocardiographic wall motion score index (WMSI) and by Doppler echocardiography of mitral valve inflow at rest and during DSE. Radionuclide ventriculography was used as an independent reference for ejection fraction (EF). A reduction of EF >/=5% occurred in 17 patients (group A) at the last follow-up. Patients without decreased EF comprised group B. Early/late diastolic velocity of mitral inflow (E/A ratio) at rest was lower in group A (0.91+/-0.2 vs 1.28+/-0.3, P<0.001), and it was an independent predictor of cardiotoxicity (adjusted for baseline patient characteristics and parameters of systolic and diastolic function). At follow-up, WMSI at rest paralleled radionuclide EF. Contractile reserve at low-dose DSE was preserved in group A. CONCLUSIONS WMSI measured by 2D echocardiography parallels radionuclide EF at follow-up. Assessment of contractile reserve has no incremental value for the early detection of cardiotoxicity. A baseline abnormal E/A ratio is an independent predictor of anthracycline cardiotoxicity.

Prognostic value of dobutamine stress echocardiography in patients with previous coronary revascularisation

Objective: To assess the prognostic value of dobutamine stress echocardiography (DSE) in patients with previous myocardial revascularisation. Design: Prospective study. Setting: Tertiary referral centre in Rotterdam, the Netherlands. Patients: 332 consecutive patients with previous percutaneous or surgical coronary revascularisation underwent DSE. Follow up was successful for 331 (99.7%) patients. Thirty eight patients who underwent early revascularisation (⩽ 3 months) after the test were excluded from analysis. Main outcome measures: Cox proportional hazards regression models were used to identify independent predictors of the composite of cardiac events (cardiac death, non-fatal myocardial infarction, and late revascularisation). Results: During a mean (SD) of 24 (20) months, 37 (13%) patients died and 89 (30%) had at least one cardiac event (21 (7%) cardiac deaths, 11 (4%) non-fatal myocardial infarctions, and 68 (23%) late revascularisations). In multivariate analysis of clinical data, independent predictors of late cardiac events were hypertension (hazard ratio (HR) 1.7, 95% confidence interval (CI) 1.1 to 2.6) and congestive heart failure (HR 2.1, 95% CI 1.3 to 3.2). Reversible wall motion abnormalities (ischaemia) on DSE were incrementally predictive of cardiac events (HR 2.1, 95% CI 1.3 to 3.2). Conclusions: Myocardial ischaemia during DSE is independently predictive of cardiac events among patients with previous myocardial revascularisation, after controlling for clinical data.

Long term outcome in patients with silent versus symptomatic ischaemia during dobutamine stress echocardiography

Objectives: To compare the long term prognosis of patients having silent versus symptomatic ischaemia during dobutamine stress echocardiography (DSE). Design: Observational study. Setting: Tertiary referral centre. Patients: 931 patients who experienced stress induced myocardial ischaemia during DSE. Results: Silent ischaemia was present in 643 of 931 patients (69%). The number of dysfunctional segments at rest (mean (SD) 9.6 (5.1) v 8.8 (5.0), p  =  0.1) and of ischaemic segments (3.5 (2.2) v 3.8 (2.1), p  =  0.2) was comparable in both groups. During a mean (SD) follow up of 5.5 (3.3) years, there were 169 (18%) cardiac deaths and 86 (9%) non-fatal infarctions. Multivariable Cox regression analysis showed age (hazard ratio (HR) 1.1, 95% confidence interval (CI) 1.02 to 1.05), previous myocardial infarction (HR 1.4, 95% CI 1.1 to 2.0), and number of ischaemic segments during the test (HR 2.0, 95% CI 1.0 to 3.7) as independent predictors of cardiac death and myocardial infarction. For every additional ischaemic segment there was a twofold increment in risk of late cardiac events. The annual cardiac death or myocardial infarction rate was 3.0% in patients with symptomatic ischaemia and 4.6% in patients with silent ischaemia (p < 0.01). Silent induced ischaemia was an independent predictor of cardiac death and myocardial infarction (HR 1.7, 95% CI 1.1 to 2.0). During follow up symptomatic patients were treated more often with cardioprotective therapy (p < 0.01) and coronary revascularisation (145 of 288 (50%) v 174 of 643 (27%), p < 0.001). Conclusions: Patients with silent ischaemia had a similar extent of myocardial ischaemia during DSE compared to patients with symptomatic ischaemia but received less cardioprotective treatment and coronary revascularisation and experienced a higher cardiac event rate.

Pulsed wave tissue Doppler imaging for the quantification of contractile reserve in stunned, hibernating, and scarred myocardium

Objectives: To assess whether quantification of myocardial systolic velocities by pulsed wave tissue Doppler imaging can differentiate between stunned, hibernating, and scarred myocardium. Design: Observational study. Setting: Tertiary referral centre. Patients: 70 patients with reduced left ventricular function caused by chronic coronary artery disease. Methods: Pulsed wave tissue Doppler imaging was done close to the mitral annulus at rest and during low dose dobutamine; systolic ejection velocity (Vs) and the difference in Vs between low dose dobutamine and the resting value (ΔVs) were assessed using a six segment model. Assessment of perfusion (with Tc-99m-tetrofosmin SPECT) and glucose utilisation (by 18F-fluorodeoxyglucose SPECT) was used to classify dysfunctional regions (by resting cross sectional echocardiography) as stunned, hibernating, or scarred. Results: 253 of 420 regions (60%) were dysfunctional. Of these, 132 (52%) were classified as stunned, 25 (10%) as hibernating, and 96 (38%) as scarred. At rest, Vs in stunned, hibernating, and scar tissue was, respectively, 6.3 (1.8), 6.6 (2.2), and 5.5 (1.5) cm/s (p  =  0.001 by ANOVA). There was a gradual decline in Vs during low dose dobutamine infusion between stunned, hibernating, and scar tissue (8.3 (2.6) v 7.8 (1.5) v 6.8 (1.9) cm/s, p < 0.001 by ANOVA). ΔVs was higher in stunned (2.1 (1.9) cm/s) than in hibernating (1.2 (1.4) cm/s, p < 0.05) or scarred regions (1.3 (1.2) cm/s, p  =  0.001). Conclusions: Quantitative tissue Doppler imaging showed a gradual reduction in regional velocities between stunned, hibernating, and scarred myocardium. Dobutamine induced contractile reserve was higher in stunned regions than in hibernating and scarred myocardium, reflecting different severities of myocardial damage.

Relation between left ventricular contractile reserve during low dose dobutamine echocardiography and plasma concentrations of natriuretic peptides

Background: In ischaemic cardiomyopathy, raised plasma concentrations of natriuretic peptides are associated with a poor long term prognosis, while the presence of contractile reserve is a favourable sign. Objective: To assess the relation between plasma natriuretic peptides and contractile reserve. Design: Prospective observational study. Setting: Tertiary referral centre. Patients: 66 consecutive patients undergoing low dose dobutamine stress echocardiography to evaluate contractile reserve in regions with contractile dysfunction at rest, divided into two groups: group 1, 31 patients with ischaemic cardiomyopathy (left ventricular ejection fraction ⩽ 40%) and heart failure symptoms; group 2, 35 patients with normal left ventricular function. Main outcome measures: Plasma atrial natriuretic peptide (ANP) and brain natriuretic peptide (BNP), measured using immunoradiometric assays. Contractile reserve was defined as an improvement in segmental wall motion score during infusion of low dose dobutamine. Results: Plasma ANP and BNP concentrations were higher in group 1 than in group 2 (mean (SD): ANP, 17.8 (32.8) v 7.2 (9.7), p < 0.005; BNP, 24.4 (69.0) v 5.0 (14.3) pmol/l, respectively; p < 0.001). In group 1, the presence of contractile reserve was inversely related to ANP and BNP levels; however, patients with contractile reserve had lower ANP and BNP concentrations than patients without contractile reserve (ANP, 14.2 (9.1) v 24.2 (44.2), p < 0.05; BNP, 20.2 (25.5) v 37.5 (93.8) pmol/l, respectively; p < 0.05). Conclusions: Plasma natriuretic peptide concentrations are raised in patients with left ventricular dysfunction, but in the presence of preserved myocardial contractile reserve, relatively low levels of ANP and BNP are present.

Improvement of stress LVEF rather than rest LVEF after coronary revascularisation in patients with ischaemic cardiomyopathy and viable myocardium

Objective: To evaluate prospectively the response of left ventricular ejection fraction (LVEF) to high dose dobutamine infusion in patients showing substantial viability, with and without improved resting LVEF after revascularisation. Methods: Before and 9–12 months after revascularisation, 50 patients with ischaemic cardiomyopathy (LVEF 32 (8)%) and substantial myocardial viability (⩾ 4 viable segments) underwent radionuclide ventriculography and dobutamine stress echocardiography. Patients were divided into group 1, patients with, and group 2, patients without significant improvement in resting LVEF (⩾ 5% by radionuclide ventriculography) after revascularisation. The response of LVEF during dobutamine stress echocardiography was compared in these two groups. Results: Groups 1 and 2 were comparable in baseline characteristics, resting LVEF, and number of viable segments (mean (SD) 7 (4) v 6 (2), not significant). After revascularisation, the LVEF response during dobutamine stress echocardiography improved significantly in both groups (group 1, 34 (10)% to 56 (8)%; group 2, 32 (10)% to 46 (11)%; both p < 0.001). Interestingly, although resting LVEF did not improve in group 2, peak stress LVEF after revascularisation did (p < 0.001). Group 1 patients had, however, a greater increase in peak stress LVEF (group 1, 22 (10)%; group 2, 13 (9)%; p < 0.01). New York Heart Association and Canadian Cardiovascular Society classes decreased in both groups. Conclusions: Although patients with viable myocardium did not always have improved rest LVEF after revascularisation, peak stress LVEF improved. Assessment of improvement of resting function may not be the ideal end point to evaluate successful revascularisation.

Quantification of regional left ventricular function in Q wave and non-Q wave dysfunctional regions by tissue Doppler imaging in patients with ischaemic cardiomyopathy

Objective: To quantify regional left ventricular (LV) function and contractile reserve in Q wave and non-Q wave regions in patients with previous myocardial infarction. Design: An observational study. Setting: Tertiary care centre. Patients: 81 patients with previous myocardial infarction and depressed LV function. Interventions: All patients underwent surface ECG at rest and pulsed wave tissue Doppler imaging at rest and during low dose dobutamine infusion. The left ventricle was divided into four major regions (anterior, inferoposterior, septal, and lateral). Severely hypokinetic, akinetic, and dyskinetic regions on two dimensional echocardiography at rest were considered dysfunctional. Main outcome measures: Regional myocardial systolic velocity (Vs) at rest and the change in Vs during low dose dobutamine infusion (ΔVs) in dysfunctional regions with and without Q waves on surface ECG. Results: 220 (69%) regions were dysfunctional; 60 of these regions corresponded to Q waves and 160 were not related to Q waves. Vs and ΔVs were lower in dysfunctional than in non-dysfunctional regions (mean (SD) Vs 6.2 (1.9) cm/s v 7.1 (1.7) cm/s (p < 0.001), and ΔVs 1.9 (1.9) cm/s v 2.6 (2.5) cm/s (p = 0.009), respectively). There were no significant differences in Vs and ΔVs among dysfunctional regions with and without Q waves (Q wave regions: Vs 6.2 (1.8) cm/s, ΔVs 1.6 (2.2) cm/s; non-Q wave regions: Vs 6.3 (1.9) cm/s, ΔVs 2.0 (2.0) cm/s). Conclusions: Quantitative pulsed wave tissue Doppler demonstrated that, among dysfunctional regions, Q waves on the ECG do not indicate more severe dysfunction, and myocardial contractile reserve is comparable in Q wave and non-Q wave dysfunctional myocardium.

926 Aortic valve sclerosis screening using a hand-held ultrasound device

were present in respectively 97%, 40%, and 60% using SE, and 92%, 33%, and 58% using the HD (p=NS). There was a good agreement between the 2 imaging devices for the sclerosis of all aortic valve cusps (right cusp 93.2%, k=0.89, left cusp 94.7%, k=0.88, non coronary cusp 81.4%, k=0.74). The agreement was also good for evaluation of MAC and ARS, respectively 89.7%, k=0.78 and 98.2%, k=0.96. During DSE wall motion abnormalities at rest and ischemic segments at peak were present respectively in 36 (50%) and 11 (23%) of patients. There was no correlation between the grade of AVS and the number of dysfunctional segments at rest (p= 0.20) or the number of ischemic segments at peak DSE (p=0.21). Conclusion: Hand-held echocardiography is a simple, reliable and inexpensive tool to screen patients for AVS, MAC and ARS. 927 The performance of hand-carried ultrasound devices for assessment of global and segmental left ventricular function is improved with the use of echocontrast.

114 Pulsed-wave tissue Doppler imaging for the quantification of contractile reserve in stunned, hibernating, and scarred myocardium

OBJECTIVES To assess whether quantification of myocardial systolic velocities by pulsed wave tissue Doppler imaging can differentiate between stunned, hibernating, and scarred myocardium. DESIGN Observational study. SETTING Tertiary referral centre. PATIENTS 70 patients with reduced left ventricular function caused by chronic coronary artery disease. METHODS Pulsed wave tissue Doppler imaging was done close to the mitral annulus at rest and during low dose dobutamine; systolic ejection velocity (Vs) and the difference in Vs between low dose dobutamine and the resting value (DeltaVs) were assessed using a six segment model. Assessment of perfusion (with Tc-99m-tetrofosmin SPECT) and glucose utilisation (by 18F-fluorodeoxyglucose SPECT) was used to classify dysfunctional regions (by resting cross sectional echocardiography) as stunned, hibernating, or scarred. RESULTS 253 of 420 regions (60%) were dysfunctional. Of these, 132 (52%) were classified as stunned, 25 (10%) as hibernating, and 96 (38%) as scarred. At rest, Vs in stunned, hibernating, and scar tissue was, respectively, 6.3 (1.8), 6.6 (2.2), and 5.5 (1.5) cm/s (p = 0.001 by ANOVA). There was a gradual decline in Vs during low dose dobutamine infusion between stunned, hibernating, and scar tissue (8.3 (2.6) v 7.8 (1.5) v 6.8 (1.9) cm/s, p < 0.001 by ANOVA). DeltaVs was higher in stunned (2.1 (1.9) cm/s) than in hibernating (1.2 (1.4) cm/s, p < 0.05) or scarred regions (1.3 (1.2) cm/s, p = 0.001). CONCLUSIONS Quantitative tissue Doppler imaging showed a gradual reduction in regional velocities between stunned, hibernating, and scarred myocardium. Dobutamine induced contractile reserve was higher in stunned regions than in hibernating and scarred myocardium, reflecting different severities of myocardial damage.