Prognostic value of dobutamine-atropine stress echocardiography early after acute myocardial infarction. Echo Dobutamine International Cooperative (EDIC) Study

Predictive Value of Cardiac Magnetic Resonance Feature Tracking after Acute Myocardial Infarction: A Comparison with Dobutamine Stress Echocardiography

In acute ST-segment elevation myocardial infarction (STEMI) late gadolinium enhancement (LGE) may underestimate segmental functional recovery. We evaluated the predictive value of cardiac magnetic resonance (CMR) feature-tracking (FT) for functional recovery and whether it incremented the value of LGE compared to low-dose dobutamine stress echocardiography (LDDSE) and speckle-tracking echocardiography (STE). Eighty patients underwent LDDSE and CMR within 5–7 days after STEMI and segmental functional recovery was defined as improvement in wall-motion at 6-months CMR. Optimal conventional and FT parameters were analyzed and then also applied to an external validation cohort of 222 STEMI patients. Circumferential strain (CS) was the strongest CMR-FT predictor and addition to LGE increased the overall accuracy to 74% and was especially relevant in segments with 50–74% LGE (AUC 0.60 vs. 0.75, p = 0.001). LDDSE increased the overall accuracy to 71%, and in the 50–74% LGE subgroup improved the AUC from 0.60 to 0.69 (p = 0.039). LGE + CS showed similar value as LGE + LDDSE. In the validation cohort, CS was also the strongest CMR-FT predictor of recovery and addition of CS to LGE improved overall accuracy to 73% although this difference was not significant (AUC 0.69, p = 0.44). Conclusion: CS is the strongest CMR-FT predictor of segmental functional recovery after STEMI. Its incremental value to LGE is comparable to that of LDDSE whilst avoiding an inotropic stress agent. CS is especially relevant in segments with 50–74% LGE where accuracy is lower and further testing is frequently required to clarify the potential for recovery.

Does stress echocardiography add incremental value to baseline ejection fraction for the early identification of candidates for implantable defibrillators?

Objective

A reduction in left ventricular ejection fraction (EF) remains the strongest indicator of increased risk of sudden cardiac death after an acute myocardial infarction (AMI). Guidelines recommend that patients with an EF ≤35%, 6–12 weeks after AMI should be considered for implantable cardioverter defibrillator (ICD) therapy. Stress echocardiography is a safe method to detect viability in a stunned myocardium. The purpose of this study was to investigate if stress echocardiography early after AMI could identify ICD candidates before discharge.

Methods

Ninety-six patients with EF ≤40% early after AMI were prospectively included in a cohort study, and investigated by baseline and stress echocardiography before discharge. Follow-up echocardiography was performed after 3 months. EF, mitral annular plane systolic excursion (MAPSE) and peak systolic velocity (PSV) were determined for each examination.

Results

There were 80 (83%) patients who completed the baseline, stress and follow-up echocardiography. Among them there were 32 (40%) patients who met the ICD criteria of EF ≤35% at 3 months. For these patients, EF, MAPSE and PSV were significantly lower than for those patients who recovered. The area under the receiver operating characteristic curve (AUC) was 85% (95% CI 0.74 to 0.94) for baseline EF to predict non-recovery. None of the other variables had a higher AUC.

Conclusion

Patients who met the ICD criteria of EF ≤35% at 3 months after myocardial infarction had lower EF, MAPSE and PSV on baseline and stress echocardiograph before discharge. Stress echocardiography did not add additional value in predicting non-recovery.

Association between fractional flow reserve, instantaneous wave-free ratio and dobutamine stress echocardiography in patients with stable coronary artery disease

AIMS

The association between fractional flow reserve (FFR) and dobutamine stress echocardiography (DSE) in real-world stable angina patients is scant and controversial whereas no such comparison exists with instantaneous wave-free ratio (iFR). The current retrospective study aimed to investigate the associations among these modalities in patients with stable coronary artery disease (CAD) and intermediate coronary lesions.

METHODS AND RESULTS

We studied 62 consecutive stable angina patients who underwent DSE and subsequently coronary angiography with FFR (in all 62) and iFR (in 46/62 patients) assessment of intermediate single-vessel lesions between 2014 and 2015. Using receiver operating characteristic (ROC) curves we sought to identify the optimal FFR and iFR cut-off points with the highest discriminative power to predict the DSE result. The kappa coefficient was used to assess the agreement between FFR, iFR and DSE. The mean age of the study cohort was 63.5±12 years and 35 (56.5%) were males. Thirteen (21%) lesions were adjudicated as causing reversible ischaemia on DSE. Using ROC (FFR predicting DSE result), the area under the curve was 0.952 (95% CI: 0.902 to 1), whereas for iFR it was 0.743 (95% CI: 0.560 to 0.927), pAUC comparison=0.03. The optimal FFR cut-off point predicting positive DSE was 0.80. There was strong agreement between DSE and FFR (kappa 0.682, p<0.001). There was only modest agreement between iFR and DSE (kappa 0.258, p=0.068) using a cut-off value of 0.9.

CONCLUSIONS

In patients referred for evaluation of stable CAD, there was good agreement between DSE and FFR (87%) but less so with iFR (71.7%).

[The Clinical use of Stress Echocardiography in Ischemic Heart Disease Cardiovascular Ultrasound (2017)15:7. Translation authors: Arystan A.Zh., Fettser D.V.]

Stress echocardiography is an established technique for the assessment of extent and severity of coronary artery disease. The combination of echocardiography with a physical, pharmacological or electrical stress allows detecting myocardial ischemia with an excellent accuracy. A transient worsening of regional function during stress is the hallmark of inducible ischemia. Stress echocardiography provides similar diagnostic and prognostic accuracy as radionuclide stress perfusion imaging or magnetic resonance, but at a substantially lower cost, without environmental impact, and with no biohazards for the patient and the physician. The evidence on its clinical impact has been collected over 35 years, based on solid experimental, pathophysiological, technological and clinical foundations. There is the need to implement the combination of wall motion and coronary flow reserve, assessed in the left anterior descending artery, into a single test. The improvement of technology and in imaging quality will make this approach more and more feasible. The future issues in stress echo will be the possibility of obtaining quantitative information translating the current qualitative assessment of regional wall motion into a number. The next challenge for stress echocardiography is to overcome its main weaknesses: dependence on operator expertise, the lack of outcome data (a widespread problem in clinical imaging) to document the improvement of patient outcomes. This paper summarizes the main indications for the clinical applications of stress echocardiography to ischemic heart disease.

The clinical use of stress echocardiography in ischemic heart disease

Stress echocardiography is an established technique for the assessment of extent and severity of coronary artery disease. The combination of echocardiography with a physical, pharmacological or electrical stress allows to detect myocardial ischemia with an excellent accuracy. A transient worsening of regional function during stress is the hallmark of inducible ischemia. Stress echocardiography provides similar diagnostic and prognostic accuracy as radionuclide stress perfusion imaging or magnetic resonance, but at a substantially lower cost, without environmental impact, and with no biohazards for the patient and the physician.

The evidence on its clinical impact has been collected over 35 years, based on solid experimental, pathophysiological, technological and clinical foundations. There is the need to implement the combination of wall motion and coronary flow reserve, assessed in the left anterior descending artery, into a single test. The improvement of technology and in imaging quality will make this approach more and more feasible. The future issues in stress echo will be the possibility of obtaining quantitative information translating the current qualitative assessment of regional wall motion into a number. The next challenge for stress echocardiography is to overcome its main weaknesses: dependance on operator expertise, the lack of outcome data (a widesperad problem in clinical imaging) to document the improvement of patient outcomes. This paper summarizes the main indications for the clinical applications of stress echocardiography to ischemic heart disease.

Stress echocardiography

Stress echocardiography is the combination of 2D echocardiography with a physical, pharmacological or electrical stress. The diagnostic end point for the detection of myocardial ischemia is the induction of a transient worsening in regional function during stress. Stress echocardiography provides similar diagnostic and prognostic accuracy as radionuclide stress perfusion imaging but at a substantially lower cost, without environmental impact and with no biohazards for the patient and the physician. In spite of its dependence upon operator's training, it is the best possible choice to achieve the still elusive target of sustainable cardiac imaging in the field of noninvasive diagnosis of coronary artery disease.

Improved clinical outcome after invasive management of patients with recent myocardial infarction and proven myocardial viability: primary results of a randomized controlled trial (VIAMI-trial)

Background

Patients with ST-elevation myocardial infarction (STEMI) not treated with primary or rescue percutaneous coronary intervention (PCI) are at risk for recurrent ischemia, especially when viability in the infarct-area is present. Therefore, an invasive strategy with PCI of the infarct-related coronary artery in patients with viability would reduce the occurrence of a composite end point of death, reinfarction, or unstable angina (UA).

Methods

Patients admitted with an (sub)acute myocardial infarction, who were not treated by primary or rescue PCI, and who were stable during the first 48 hours after the acute event, were screened for the study. Eventually, we randomly assigned 216 patients with viability (demonstrated with low-dose dobutamine echocardiography) to an invasive or a conservative strategy. In the invasive strategy stenting of the infarct-related coronary artery was intended with abciximab as adjunct treatment. Seventy-five (75) patients without viability served as registry group. The primary endpoint was the composite of death from any cause, recurrent myocardial infarction (MI) and unstable angina at one year. As secondary endpoint the need for (repeat) revascularization procedures and anginal status were recorded.

Results

The primary combined endpoint of death, recurrent MI and unstable angina was 7.5% (8/106) in the invasive group and 17.3% (19/110) in the conservative group (Hazard ratio 0.42; 95% confidence interval [CI] 0.18-0.96; p = 0.032). During follow up revascularization-procedures were performed in 6.6% (7/106) in the invasive group and 31.8% (35/110) in the conservative group (Hazard ratio 0.18; 95% CI 0.13-0.43; p < 0.0001). A low rate of recurrent ischemia was found in the non-viable group (5.4%) in comparison to the viable-conservative group (14.5%). (Hazard-ratio 0.35; 95% CI 0.17-1.00; p = 0.051).

Conclusion

We demonstrated that after acute MI (treated with thrombolysis or without reperfusion therapy) patients with viability in the infarct-area benefit from a strategy of early in-hospital stenting of the infarct-related coronary artery. This treatment results in a long-term uneventful clinical course. The study confirmed the low risk of recurrent ischemia in patients without viability.

Trial registration

ClinicalTrials.gov: NCT00149591.

Acute and chronic myocardial infarction in a pig model: utility of multi-slice cardiac computed tomography in assessing myocardial viability and infarct parameters

OBJECTIVES

The aim of this study was to determine the feasibility of multi-slice computed tomography (MSCT) biphasic imaging in assessing myocardial viability and infarct parameters in both acutely and chronically infarcted pig models.

MATERIALS AND METHODS

Seven pigs underwent ligation of the distal left anterior descending artery. Imaging was performed on the day of infarction and 3 months post-infarct, with contrast infusion followed by MSCT scan acquisition at different time-points. Left ventricular ejection fractions (LVEFs) were obtained by left ventriculography (LVG) after 3 months. Infarcted locations found using MSCT were compared with those obtained using SPECT. Infarcted areas were also analysed histopathologically and compared with the findings from MSCT.

RESULTS

Chronic phase images had perfusion defects with lower CT values relative to normal myocardium (43±10HU vs. 156±13HU, p=0.001) on the early images but no residual defects on delayed images. However, we found hyperenhancing regions on delayed images (244±20HU vs. 121±25HU, p=0.001), and good correlation between MSCT- and LVG-derived LVEFs (60.56±7.56%). The areas identified by MSCT corresponded to the location of (201)Tl SPECT-/pathologic staining-derived regions in all models. Infarct size was in good agreement with MSCT and pathological analyses of chronic phase models.

CONCLUSIONS

Necrotic myocardium in different stages after infarction could be qualitatively and quantitatively assessed using MSCT biphasic imaging, as could the status of microcirculation formation. MSCT-measured LVEFs matched well with other modalities, and hence MSCT is a useful tool in assessing post-infarct cardiac function.

Cardiac imaging after myocardial infarction

After myocardial infarction, optimal clinical management depends critically on cardiac imaging. Remodelling and heart failure, presence of inducible ischaemia, presence of dysfunctional viable myocardium, future risk of adverse events including risk of ventricular arrhythmias, need for anticoagulation, and other questions should be addressed by cardiac imaging. Strengths and weaknesses, recent developments, choice, and timing of the different non-invasive techniques are reviewed for this frequent clinical scenario.

Assessment of acute myocardial infarction: current status and recommendations from the North American society for Cardiovascular Imaging and the European Society of Cardiac Radiology

There are a number of imaging tests that are used in the setting of acute myocardial infarction and acute coronary syndrome. Each has their strengths and limitations. Experts from the European Society of Cardiac Radiology and the North American Society for Cardiovascular Imaging together with other prominent imagers reviewed the literature. It is clear that there is a definite role for imaging in these patients. While comparative accuracy, convenience and cost have largely guided test decisions in the past, the introduction of newer tests is being held to a higher standard which compares patient outcomes. Multicenter randomized comparative effectiveness trials with outcome measures are required.

Contractile reserve and extent of transmural necrosis in the setting of myocardial stunning: comparison at cardiac MR imaging

PURPOSE

To perform a comparison of cardiac magnetic resonance (MR) imaging-derived ejection fraction (EF) during low-dose dobutamine infusion (EF(D)) with the extent of segments with transmural necrosis in more than 50% of their wall thickness (ETN) for the prediction of major adverse cardiac events (MACEs) and late systolic recovery soon after a first ST-segment elevation myocardial infarction (STEMI).

MATERIALS AND METHODS

Institutional ethics committee approval and written informed consent were obtained. One hundred nineteen consecutive patients with a first STEMI, a depressed left ventricular EF, and an open infarct-related artery underwent MR imaging at 1 week after infarction. EF(D) and ETN (by using a 17-segment model) were determined, and the prediction of MACEs and systolic recovery at follow-up was assessed by using area under the receiver operating characteristic curve (AUC) and multivariable regression analysis.

RESULTS

During follow-up (median, 613 days; range, 312-1243 days), 18 MACEs (five cardiac deaths, six myocardial infarctions, seven readmissions for heart failure) occurred. MACEs were associated with a lower EF(D) (43% +/- 12 [standard deviation] vs 49% +/- 10, P = .02) and a larger ETN (seven segments +/- three vs four segments +/- three, P < .001). Patients with systolic recovery (increase in EF of >5% at follow-up compared with baseline EF, n = 44) displayed a higher EF(D) (51% +/- 10 vs 47% +/- 9, P = .04) and a smaller ETN (three segments +/- two vs five segments +/- three, P = .002) at 1 week. ETN and EF(D) both related to MACEs (AUC: 0.78 vs 0.67, respectively, P = .1) and systolic recovery (AUC: 0.68 vs 0.62, respectively, P = .3). According to multivariable analysis, ETN was the only MR variable associated with time to MACEs (hazard ratio, 1.38; 95% confidence interval: 1.19, 1.60; P < .001) and systolic recovery (odds ratio, 0.76; 95% confidence interval: 0.64, 0.92; P = .004) independent of baseline characteristics.

CONCLUSION

ETN is as useful as EF(D) for the prediction of MACEs and systolic recovery soon after STEMI.

Prognostic value of dobutamine stress echocardiography in diabetic patients

CAD is the main cause of morbidity and mortality in diabetic patients; we need reliable clinical parameters to stratify cardiovascular risk in these patients. We thus assessed prognostic value of clinical parameters, rest and stress echocardiographic data in diabetic patients, with known or suspected CAD. We studied 322 type 2 diabetic patients, who underwent dobutamine stress echocardiography (DSE) for known or suspected CAD; for prognostic assessment, end-points were all-cause mortality and hard cardiac events (cardiac death and non fatal myocardial infarction). During DSE, viability and inducible ischemia developed in 65 (20%) and 192 (60%) subjects, respectively; a severe ischemia (an asynergic area including more than 40% of all segments combined with a rate pressure product < 17,000) appeared in 88 (27%). Presence of a diabetic treatment or microvascular diabetic complications didn't influence prognosis, while a longer diabetes duration was associated with a higher all-cause mortality at univariate analysis. At multivariate analysis, an advanced age (RR = 1.108, CI: 1.039-1.182, P = 0.002), a lower left ventricular ejection fraction (RR = 0.956, CI: 0.919-0.994, P = 0.025) and, tendentially, peripheral vascular disease (RR = 2.942, CI: 0.985-8.785, P = 0.053) independently determined an increased all-cause mortality. New hard cardiac events occurred more frequently in presence of peripheral vascular disease (RR = 2.975, CI: 1.339-6.608, P = 0.007), viability (RR = 3.427, CI: 1.400-8.390, P = 0.007) and severe ischemia (RR = 3.245, CI: 1.503-7.005, P = 0.003). In diabetic patients with known or suspected CAD, presence of viability and severe ischemia during DSE are independently associated with higher occurrence of hard cardiac events.

Recent advances in dobutamine stress echocardiography

Dobutamine stress echocardiography (DSE) is a reliable cardiac risk stratifier that has widespread applicability because of its clinical accuracy and cost effectiveness. Dobutamine has positive inotropic and chronotropic effects and is commonly used in patients who cannot exercise or achieve an adequate heart rate response with exercise. Recently available long-term results from several independent clinical trials, combined with enhancements in image quality, have improved the ability to detect significant coronary artery disease and determine myocardial viability. Dobutamine stress echocardiography has an excellent safety profile with clinical results superior to regular exercise electrocardiography and comparable with exercise echocardiography and radionucleotide perfusion stress imaging. Low-dose dobutamine response can accurately predict dysfunctional yet viable myocardial regions that may improve with revascularization. Clinical studies are now available refining the common use of DSE preoperatively in female patients with valvular disease, as well as in the emergency department. Dobutamine stress echocardiography does have some limitations in discriminating particular regions of ischemia when multiple ventricular segments are involved and when the imaging is suboptimal. It can be applied using minimal additional resources in an otherwise functioning echocardiography laboratory and, with appropriate training, can result in clinical results comparable with those of large-scale multicenter trials. Ongoing improvements in technology and the development of new reagents such as myocardial contrast agents hold promise for further advancement in the near future.

Incidence and significance of profound hypotension during dobutamine stress echocardiography

BACKGROUND

Mild hypotension (drops of systolic blood pressure of > or = 20 mmHg) occurs in 14-38% of dobutamine stress echo (DSE) and carries a good prognosis for subsequent cardiac events. The incidence and significance of more profound hypotension (PH) (> or = 50 mmHg) is unknown.

HYPOTHESIS

The aim of the study was to determine the incidence of PH during DSE and its prognosis for subsequent cardiac events.

METHODS

We reviewed 617 DSE performed at our institution between 1992 and 1996 and identified two DSE subgroups. The first group (PH group) consisted of all patients with PH during DSE. A second group was selected with baseline characteristics similar to the PH group but without PH during DSE (non-PH group). Follow-up was by a physician chart review and direct telephone contact. Cardiac event rates were determined for hard [myocardial infarction (MI), or cardiac death] and soft (angina, congestive heart failure, coronary angioplasty, or coronary bypass surgery) events occurring after the DSE.

RESULTS

Of the 617 DSE performed, 16 (3%) patients developed PH (PH group) during DSE, with 13 showing no inducible ischemia. The hard and soft cardiac event rate in this 13 PH group was 46% (mean follow-up of 28.7 +/- 18 months). Of the non-PH group, 32 patients had a negative DSE with a coronary event rate of 12.5%. Profound hypotension correlated with a significantly higher cardiac event rate (p < 0.02).

CONCLUSIONS

The incidence of PH during DSE is low (3%) and appears to predict a worse prognosis for subsequent cardiac events.

Prognostic value of exercise stress test and dobutamine stress echo in patients with known coronary artery disease

BACKGROUND

The aim of this study was to compare the feasibility of dobutamine stress echocardiography (DSE) and exercise stress test (EST) between patients in different age groups and to evaluate their proportional prognostic value in a population with established coronary artery disease (CAD).

METHODS

The study sample included 323 subjects, subdivided in group 1 (G1), comprising 246 patients aged <75 years, and group 2 (G2), with 77 subjects aged >or=75 years. DSE and EST were performed before enrollment in a cardiac rehabilitation program; for prognostic assessment, end points were all-cause mortality and hard cardiac events (cardiac death or nonfatal myocardial infarction).

RESULTS

During DSE, G2 patients showed worse wall motion score index (WMSI), but the test was stopped for complications in a comparable proportion of cases (54 G1 and 19 G2 patients, P = NS). EST was inconclusive in similarly high proportion of patients in both groups (76% in G1 vs. 84% in G2, P = NS); G2 patients reached a significantly lower total workload (6 +/- 1.6 METs in G1 vs. 5 +/- 1.2 METs in G2, P < 0.001). At multivariate analysis, a lower peak exercise capacity (HR 0.566, CI 0.351-0.914, P = 0.020) was associated with higher mortality, while a high-dose WMSI >2 (HR 5.123, CI 1.559-16.833, P = 0.007), viability (HR 3.354, CI 1.162-9.678, P = 0.025), and nonprescription of beta-blockers (HR 0.328, CI 0.114-0.945, P = 0.039) predicted hard cardiac events.

CONCLUSION

In patients with known CAD, EST and DSE maintain a significant prognostic role in terms of peak exercise capacity for EST and of presence of viability and an extensive wall motion abnormalities at peak DSE.

Stress echocardiography expert consensus statement: European Association of Echocardiography (EAE) (a registered branch of the ESC)

Stress echocardiography is the combination of 2D echocardiography with a physical, pharmacological or electrical stress. The diagnostic end point for the detection of myocardial ischemia is the induction of a transient worsening in regional function during stress. Stress echocardiography provides similar diagnostic and prognostic accuracy as radionuclide stress perfusion imaging, but at a substantially lower cost, without environmental impact, and with no biohazards for the patient and the physician. Among different stresses of comparable diagnostic and prognostic accuracy, semisupine exercise is the most used, dobutamine the best test for viability, and dipyridamole the safest and simplest pharmacological stress and the most suitable for combined wall motion coronary flow reserve assessment. The additional clinical benefit of myocardial perfusion contrast echocardiography and myocardial velocity imaging has been inconsistent to date, whereas the potential of adding - coronary flow reserve evaluation of left anterior descending coronary artery by transthoracic Doppler echocardiography adds another potentially important dimension to stress echocardiography. New emerging fields of application taking advantage from the versatility of the technique are Doppler stress echo in valvular heart disease and in dilated cardiomyopathy. In spite of its dependence upon operator's training, stress echocardiography is today the best (most cost-effective and risk-effective) possible imaging choice to achieve the still elusive target of sustainable cardiac imaging in the field of noninvasive diagnosis of coronary artery disease.

Risk Stratification and Prognosis in Octogenarians Undergoing Stress Echocardiographic Study

BACKGROUND

The prognostic value of stress echocardiography (SE) for the diagnosis and risk stratification of coronary artery disease in octogenarians is not well defined.

METHODS

Follow-up of 5 years (mean 2.9 +/- 1.0 years) for confirmed nonfatal myocardial infarction (n = 17) and cardiac death (n = 37) was obtained in 335 patients, age > or =80 years (mean age 84 +/- 3 years, 44% male), undergoing SE (33% treadmill, 67% dobutamine). Left ventricular (LV) regional wall motion was assessed by a consensus of two echocardiographers and scored as per standard five-point scale, 16-segment model of wall motion analysis. Ischemic LV wall segment was defined as deterioration in the thickening and excursion during stress (increase in wall-motion score index (WMSI) > or =1).

RESULTS

By univariate analysis, inducible ischemia (chi-square = 38.4, P < 0.001), left ventricular ejection fraction (chi-square = 41.2, P < 0.001), a history of previous myocardial infarction (chi-square = 22.3, P < 0.01), hypertension (chi-square = 33, P < 0.01), and age (chi-square = 27.7, P < 0.01) were significant predictors of future cardiac events. WMSI, an index of inducible ischemia, provided incremental prognostic information when forced into a multivariable model where clinical and rest echocardiography variables were entered first. WMSI effectively stratified octogenarians into low- and high-risk groups (annualized event rates of 1.2 versus 5.8%/year, P < 0.001).

CONCLUSIONS

Stress echocardiography yields incremental prognostic information in octogenarians and effectively stratifies them into low- and high-risk groups. Precise therapeutic decision making in very elderly patients should incorporate combined clinical and stress echocardiography data.

Assessment of myocardial viability in a reperfused porcine model: evaluation of different MSCT contrast protocols in acute and subacute infarct stages in comparison with MRI

OBJECTIVE

To assess myocardial viability in acute and subacute infarcts using different multislice spiral computed tomography contrast protocols with magnetic resonance imaging (MRI) correlation.

METHODS

Seven pigs were studied with 64-multislice spiral computed tomography and MRI (1.5 T) at a median of 1 and 21 days after temporary occlusion of the second diagonal branch. Computed tomography was performed at 3, 5, 10, and 15 minutes after injection of contrast medium. Contrast agent was applied either as a bolus (protocol 1; n = 7 for the first; n = 5 for the second scan) or as a bolus plus 30 mL of subsequent 0.1 mL/s low-flow (protocol 2; n = 7 for the first; n = 6 for the second scan). Finally, histological sections were obtained. Volumes of infarcted myocardium were assessed as the percentage of the left ventricle. Computed tomography attenuation values were obtained, and image quality was assessed.

RESULTS

When compared with protocol 1, protocol 2 provided greater Hounsfield unit attenuation difference between viable and nonviable myocardium at 5, 10, and 15 minutes (P = 0.19; 0.003; 0.0006) and an additional significant contrast between nonviable myocardium and ventricular blood at 3 and 5 minutes (P < 0.001). Image quality was rated significantly higher with the use of protocol 2 at 5, 10, and 15 minutes (P < or = 0.027) and for all time points use of protocol 2 resulted in improved correlation of acute and subacute infarct size with MRI.

CONCLUSIONS

Good correlation of infarct zones with MRI was achieved for both acute and subacute infarcts. With the use of a bolus/low-flow protocol, image quality was substantially improved by means of a higher tissue contrast.

Sixty-four-MSCT in the characterization of porcine acute and subacute myocardial infarction: determination of transmurality in comparison to magnetic resonance imaging and histopathology

OBJECTIVE

The aim of this study was to assess the accuracy of MSCT in characterizing myocardial infarction (MI) and, thereby, determine the extent of early perfusion defect (ED), microvascular obstruction (MO) and transmural depth of late enhancement (LE) in comparison to MRI and histology.

MATERIALS AND METHODS

Seven pigs were studied with MSCT (Somatom Sensation 64) and MRI (Magnetom Sonata) a median 1 and 21 days following temporary occlusion of a diagonal branch and creation of small reperfused infarction. For depiction of ED, CT images were acquired in the early arterial phase and following 35 s; LE and MO were evaluated on images obtained at 3, 5, 10 and 15 min. Thereby, a bolus/low-flow contrast injection protocol was used. Triphenyltetrazolium-chloride (TTC) stain and histology were obtained. Volumes of enhancement patterns were assessed as percentage of the ventricle and compared by Bland-Altman analysis. Segmental co-localization and graded transmurality was evaluated with weighted-kappa-test.

RESULTS

Close spatial agreement was observed for MRI-MO and MSCT-MO (bias=0.55; CI=-1.49 to 2.60 at 5 min MSCT), TTC and MSCT-LE (bias=-1.28; CI=-3.76 to 1.19) or MRI-LE and MSCT-LE (bias=-0.79; CI=-4.19 to 2.60). There was good segmental co-localization for MO (weighted kappa=0.93) and high agreement for transmural extent of TTC, MRI-LE and MSCT-LE (weighted kappa=0.84 TTC versus MSCT; 0.86 MRI versus MSCT). Arterial and 35s ED significantly underestimated infarct size and showed poor segmental or transmural agreement (weighted kappa=0.33; 0.44).

CONCLUSIONS

MSCT late-scans not only reliably depict size of MO and LE in acute or subacute infarct phases but, moreover, allow for accurate determination of LE transmurality.

Predischarge exercise electrocardiogram and stress echocardiography can predict long-term clinically driven revascularization following acute myocardial infarction

BACKGROUND

Predischarge stress testing provides suboptimal prediction of spontaneous hard events following uncomplicated acute myocardial infarction (AMI).

HYPOTHESIS

This study was aimed at assessing whether soft cardiac ischemic events requiring late revascularization could be predicted more accurately.

METHODS

In all, 428 patients undergoing exercise electrocardiography (ECG) and stress echocardiography (SE, 345 dobutamine and 83 dypiridamole) within 15 days of uncomplicated AMI were followed up for 425 (range 20-2220) days. Soft ischemic events (effort angina>class II [Canadian Cardiovascular Society Classification] and unstable angina) driving late (>6 months) revascularization were regarded as endpoints.

RESULTS

A total of 58 events (29 effort and 29 unstable angina with subsequent 47 coronary artery bypass grafts and 11 percutaneous transluminal coronary angioplasties) occurred: 26 in patients with positive exercise ECG and 34 in patients with positive SE. Univariate predictors of revascularizations were positive exercise ECG (p = 0.0001), peak wall motion score index (WMSI) (p = 0.0009), low workload (p = 0.0018), rest WMSI (p = 0.02) and positive SE (p = 0.02). Cox multivariate analysis selected peak WMSI, positive exercise ECG, and low workload positive exercise ECG as independent predictors of late revascularizations.

CONCLUSIONS

Predischarge stress testing identifies the long-term occurrence of soft ischemic events driving late revascularization after uncomplicated AMI.

Prognostic role of dobutamine stress echocardiography in myocardial viability

PURPOSE OF REVIEW

The aim of this review is to provide a perspective on the role of dobutamine stress echocardiography to evaluate myocardial viability and assess prognosis in patients with ischemic left ventricular dysfunction.

RECENT FINDINGS

Pooled analysis of currently available data demonstrates that dobutamine stress echocardiography provides useful information on recovery of dysfunctional but viable myocardium and prognosis. In fact, improvement of long-term prognosis may be the ultimate clinical challenge in the management of patients with ischemic left ventricular dysfunction. Dobutamine stress echocardiography can be used to assess residual ischemia and contractile reserve, which are significant determinants of prognosis. Additionally, other echocardiographic variables, such as end-diastolic wall thickness, end-systolic volume, and extent of viability, affect outcome after revascularization in patients with ischemic cardiomyopathy.

SUMMARY

Dobutamine stress echocardiography provides information on myocardial ischemia, contractile reserve, and other prognostically relevant parameters in patients with ischemic left ventricular dysfunction. This information can be used to select the optimal treatment strategy for these patients and to estimate and improve clinical outcome.

Incremental Prognostic Value of Stress Echocardiography Over Clinical and Stress Electrocardiographic Variables in Patients With Prior Myocardial Infarction: "Warranty Time" of a Normal Stress Echocardiogram

BACKGROUND

Patients with prior myocardial infarction (MI) are at increased risk of subsequent cardiac events (MI or cardiac death). The incremental prognostic value and warranty time of a normal stress echocardiogram in this high-risk population is not well defined.

METHODS

We evaluated 251 consecutive patients (62 +/- 11 years; 64% males) with remote history of MI (>6 weeks) undergoing stress echocardiography (83% dobutamine). Ischemia was defined as a new reversible wall motion abnormality and/or biphasic response. Follow-up for up to 4 years (mean 2.9 +/- 1.0 years) for confirmed MI (n = 7) and cardiac death (n = 15) were obtained.

RESULTS

Stress echocardiography effectively risk stratified patients into normal versus abnormal subgroups (Event rate 0.8% per year vs 4.2% per year; P = 0.01; RR = 5.6, 95% CI = 1.3-24.7). In patients with a normal stress echocardiogram, the event rate at the end of 6, 12, and 18 months were <1% per year. After 18 months the event rate in patients with a normal stress echocardiogram increased greatly (>1% per year). Stress echocardiography yields incremental prognostic value over clinical and stress electrocardiographic variables (Global chi-square increased from 12.4 to 25 to 31.1, P < 0.0001 both groups).

CONCLUSIONS

Stress echocardiography yields appropriate risk stratification and prognosis and provides incremental prognostic value over clinical and stress electrocardiographic variables even in patients with prior MI. A normal stress echocardiogram portends a benign prognosis (<1% event rate/year) for up to 18 months.

Late myocardial enhancement assessed by 64-MSCT in reperfused porcine myocardial infarction: diagnostic accuracy of low-dose CT protocols in comparison with magnetic resonance imaging

The purpose was to assess the practicability of low-dose CT imaging of late enhancement in acute infarction. Following temporary occlusion of the second diagonal branch, seven pigs were studied by multislice computed tomography (MSCT) and magnetic resonance imaging (MRI). Thus, 64-slice CT was performed at 3, 5, 10 and 15 min following the injection of contrast medium according to a bolus/low-flow protocol. Standard parameters of 120 kV and 800 mAs were compared with 80 kV and 400 mAs in various combinations. Infarct volumes were assessed as percentage of the ventricle for both MSCT and MR images. CT density values for viable and infarcted myocardium were obtained and image quality assessed. Mean infarct volume as measured by MRI was 12.33+/-7.06%. MSCT achieved best correlation of volumes at 5 and 10 min. Whilst lowering of tube current resulted in poor correlation, tube voltage did not affect accuracy of infarct measurement (r (2)=0.92 or 0.93 at 5 min, 800 mAs and 80 or 120 kV). In terms of image quality, greater image noise with 80 kV was compensated by significantly better contrast enhancement between viable and non-viable myocardium at lower voltage. Myocardial viability can accurately be assessed by MSCT at 80 kV, which ensures higher contrast for late enhancement and yields good correlation with MRI.

Traditional and Color M-Mode Parameters of Left Ventricular Diastolic Function During Low-dose Dobutamine Stress Echocardiography: Relations to Contractility Reserve

BACKGROUND

Cross-sectional studies reported that left ventricular (LV) systolic and diastolic functions are correlated. However, whether changes in wall-motion score index (WMSI) or 2-dimensional ejection fraction (EF) predict changes of Doppler parameters of LV diastolic function is unclear.

METHODS

Patients with known or suspected history of coronary artery disease underwent assessment of LV systolic function (WMSI, EF) and diastolic function at baseline and during stress echocardiography by low-dose dobutamine (LDD) (peak infusion 10 microg/kg/min). Peak velocities of early (E) and late (A) LV filling waves and E wave deceleration time were measured according to standard protocol. E wave propagation rate (EVp) was assessed by color Doppler M-mode across the mitral valve. Tei index was calculated as: (A wave to E wave time - ejection time)/ejection time. Changes at LDD were calculated as: 100 x (value at LDD - value at baseline)/baseline.

RESULTS

The study group comprised 66 patients, mean age 61 +/- 10 years, 80% men. Worse LV systolic function was associated with more severely impaired LV diastolic function both at baseline and at LDD. However, percent change of WMSI and change in EF did not correlate with percent change of EVp and E/E wave propagation rate, but with percent change of Tei index. At LDD, patients with myocardial viability did not show greater percent change of LV diastolic function parameters but significantly lower Tei index.

CONCLUSIONS

In patients with suspected or known coronary artery disease, assessment of diastolic function reserve by LDD stress echocardiography using traditional and color M-mode Doppler may add quantitative information on myocardial function beyond traditional assessment of contractility reserve by WMSI or EF.

Prognostic significance of ST-segment elevation during dobutamine stress echocardiography

BACKGROUND

Limited data are available concerning the significance of ST-segment elevation during dobutamine stress echocardiography (DSE). The purpose of this study was to assess the prognostic significance of new ST-segment elevation during DSE and its relationship to angiographic severity of coronary artery disease (CAD).

METHODS

From 4240 consecutive patients who had DSE, we identified 134 (3%) patients with new stress-induced ST-segment elevation > or =1 mm in at least two contiguous electrocardiographic leads. Significant CAD was considered as > or =50% diameter obstruction by angiography. Follow-up was obtained for cardiac events.

RESULTS

Age was 69 +/- 10 years; 84 (63%) were men. ST-segment elevation developed in the anterior leads in 55 (41%), inferior leads in 100 (75%), and lateral leads in 54 (40%); 56 (42%) had ST elevation in more than one region. Dobutamine stress echocardiography was abnormal in all patients; 115 (86%) had ischemia. Coronary angiography was obtained in 69 (51%) patients. Stenosis was > or =70% diameter in 68 (99%) patients and multivessel in 53 (77%). Follow-up (2.6 +/- 2.8 years) was obtained in all 134 patients. Events occurred in 103 (77%) patients, including death in 53, coronary revascularization in 33, myocardial infarction in 12, and unstable angina in 5. Event-free survival was 55% at 2 years, 38% at 4 years, and 28% at 5 years.

CONCLUSIONS

Patients with stress-induced ST-segment elevation during DSE commonly have severe CAD and are at high risk for events during follow-up. These patients should be considered for coronary angiography.

The use of stress echocardiography for prognostication in coronary artery disease: an overview

PURPOSE OF REVIEW

Stress echocardiography has a high accuracy for the detection of coronary artery disease. Additionally, it provides clinically useful prognostic information, such as resting left ventricular function, myocardial viability, stress-induced ischemia, vascular extent of wall motion abnormalities, and changes in end-systolic volume and ejection fraction with stress.

RECENT DEVELOPMENTS

The timing, extent, and severity of the stress-induced wall motion abnormalities are important determinants of long-term prognosis. Previous studies have shown the efficacy of stress echocardiography in predicting long-term cardiac events in mixed patient groups and the value of this test in selected patient subsets.

SUMMARY

This review attempts to define the role of stress echocardiography for prognostication in coronary artery disease, pointing out the ability of this technique to identify low-risk and high-risk subsets among patients with known or suspected coronary artery disease and thus guide patient management decisions.

The Doppler myocardial performance index during low-dose dobutamine echocardiography predicts mortality and left ventricular dilation after a first acute myocardial infarction

BACKGROUND

Myocardial viability can be detected by wall motion analysis during low-dose dobutamine echocardiography (LDDE) after acute myocardial infarction (AMI). However, wall motion analysis describes only left ventricular (LV) systolic reserve. The Doppler myocardial performance index (MPI) is a quantitative measure of combined LV systolic and diastolic function. We hypothesized that an increase (deterioration) in MPI during LDDE, reflecting reduced systolic and diastolic LV reserve, could provide prognostic information beyond conventional systolic wall motion analysis on mortality, morbidity, and LV remodeling after AMI.

METHODS

Low-dose dobutamine echocardiography (10 microg/kg per minute) was performed within 24 hours and echocardiography was repeated 5 days and 1, 3, and 6 months after a first AMI in 162 consecutive patients. Patients were followed for 25 +/- 11 months. End points were all-cause mortality and cardiac events (cardiac death or readmission for heart failure or reinfarction).

RESULTS

In 72 (44%) patients, MPI increased during LDDE. This was independently associated with subsequent LV dilation at 6 months of follow-up (beta = .73, P < .0001). An increase in MPI during LDDE was a powerful prognostic indicator and remained a predictor of mortality (HR 1.92, 95% CI 1.36-2.71, P < .0001) and cardiac events (HR 2.45, 95% CI 1.83-3.27, P < .0001) after adjustment for clinical data, indices of LV function at rest, and wall motion analysis during LDDE.

CONCLUSIONS

Early after AMI, deterioration in MPI during LDDE predicts subsequent LV dilation and provides prognostic information incremental to clinical data, indices of LV function at rest, and conventional stress echocardiographic data.

Long-term prognostic value of ejection fraction changes during dobutamine???atropine stress echocardiography

OBJECTIVE

Dobutamine stress echocardiography (DSE), using subjective wall motion scoring, provides incremental prognostic information over clinical data. The aim of the study was to test the additional prognostic value of left ventricular ejection fraction (LVEF) changes during DSE at different stages.

METHODS

The study population comprised 106 consecutive patients (mean age 60+/-11 years, 73% men) with suspected or known coronary artery disease referred for DSE. Stress-induced ischemia was defined as new or worsening wall motion abnormalities. LVEF was measured at rest, peak stress and recovery. Follow-up was successful in 104 (98%) patients. Four patients who underwent revascularization within 60 days were excluded from the analysis. End-points during follow-up were cardiac death, non-fatal myocardial infarction and late revascularization.

RESULTS

During a mean follow-up of 5.3+/-2.1 years, 26% of patients died: 13% due to cardiac death, 6% patients experienced non-fatal myocardial infarction and 38% underwent late revascularization. Rest-to-peak LVEF increase was lower in patients who experienced cardiac death or non-fatal myocardial infarction (4.9+/-8.6 compared with 9.2+/-7.5, P=0.04) and any cardiac events (6.0+/-8.5 compared with 10.5+/-6.7, P=0.004). An inverse correlation was found between left ventricular ejection increase and the number of ischemic segments (P<0.0001). A multivariable Cox proportional hazard model demonstrated that, in addition to clinical data and new wall motion abnormalities, lower LVEF increase had an incremental prognostic value in predicting hard cardiac events (hazard ratio 1.1, 95% confidence interval 1.0-1.2).

CONCLUSION

Failure of LVEF to significantly increase during DSE, denoting more extensive ischemia, identifies a higher-risk subgroup for late cardiac events.

Comparison of prognostic value of negative dobutamine stress echocardiography versus single-photon emission computed tomography after acute myocardial infarction

We enrolled 196 patients who had myocardial infarction and no ischemia on dobutamine stress echocardiography (DSE) and/or single-photon emission computed tomography (SPECT). Negative studies were observed in 125 patients on DSE and in 159 on SPECT. Patients were followed for 43 +/- 14 months. Cardiac events occurred in 14% of patients who did not have ischemia on DSE and in 9% of patients who did not have ischemia on SPECT. Event-free survival rate was higher in the presence of negative findings on SPECT compared with DSE (p <0.05). The lack of residual myocardial ischemia on SPECT identifies patients at low risk of events, and a negative finding on stress SPECT is superior to a negative finding on DSE.

Diagnostic Accuracy and Prognostic Value of Dobutamine Stress Myocardial Contrast Echocardiography in Patients with Suspected Acute Coronary Syndromes

BACKGROUND

Both early stress testing and cardiac troponin I (cTnI) measurements are useful in assessing the prognosis of patients with acute coronary syndrome (ACS). We sought to determine the accuracy and prognostic value of wall motion analysis (WMA) and myocardial perfusion analysis (MPA) with real-time myocardial contrast echocardiography (RTMCE) during dobutamine stress in this patient population.

METHODS

We performed dobutamine stress RTMCE to assess perfusion in 158 consecutive patients (mean age: 61 +/- 13 years) with chest pain and possible ACS. Of these, 119 had normal cTnI, while 39 had isolated elevations of cTnI (range: 0.5-9.0 ng/ml). Quantitative angiography was performed within 1 month of RTMCE in 61 patients. Patients were followed for 16 months (range: 6-46 months). Cardiac events included death, nonfatal myocardial infarction, recurrent unstable angina, or need for urgent revascularization.

RESULTS

The sensitivity, specificity, and accuracy of MPA for detecting a >50% coronary stenosis were 92%, 77%, and 88%, respectively, while they were 62%, 85%, and 67% for WMA. Three-year event-free survival was 87% in patients with negative WMA and MPA, 49% in those with positive WMA and MPA, and 51% in patients with negative WMA but positive MPA. Age-adjusted multivariate analysis demonstrated that the only independent predictors of cardiac events were a positive MPA (hazard ratio = 3.23; 95% CI = 1.23-8.49) and male sex (hazard ratio = 3.29; 95% CI = 1.21-8.97).

CONCLUSIONS

In patients suspected of having an ACS, RTMCE improved the accuracy of dobutamine stress echocardiography for detecting coronary artery disease, and was an independent predictor of outcome.

Comparison of all-cause mortality in women with known or suspected coronary artery disease referred for dobutamine stress echocardiography with normal versus abnormal test results

The presence of myocardial ischemia during dobutamine stress echocardiography is independently associated with an increased risk of all-cause mortality in women after adjustment for clinical data. This association is observed in patients who have proved coronary artery disease and in patients who have no history of coronary artery disease.

Myocardial viability assessed by dobutamine stress echocardiography predicts reduced mortality early after acute myocardial infarction: determining the risk of events after myocardial infarction (DREAM) study

OBJECTIVE

To establish further the role of dobutamine stress echocardiography (DSE) in prognostication of outcome early after acute myocardial infarction (AMI) METHODS: Consecutive patients presenting with AMI were screened for inclusion into the study. 212 stable consenting patients underwent DSE a mean (SD) of 4.8 (1.5) days after AMI. Patients were then followed up for 803 (297) days.

RESULTS

The mean (SD) resting systolic wall thickening index (SWTI) was 1.6 (0.4), 44% patients had evidence of viability at low dose, and 38% had evidence of ischaemia. During the follow up period 27 (13%) patients died and 16 (8%) had a non-fatal AMI. Independent predictors of both mortality and combined mortality and non-fatal AMI were age (hazard ratio (HR) 1.04/year, p = 0.01, and HR 1.03/year, p = 0.04, respectively) and SWTI at low dose (HR 3.6, p < 0.01, and HR 2.5, p = 0.02, respectively). Low dose DSE provided incremental information over clinical and resting left ventricular function data for predicting death and non-fatal AMI. For patients who were not revascularised SWTI at peak dose dobutamine was the only independent predictor of mortality.

CONCLUSION

DSE is a powerful predictor of outcome in stable survivors of AMI. The presence of myocardial viability has a positive impact on survival.

Non-invasive assessment of myocardial ischaemia using new real-time three-dimensional dobutamine stress echocardiography: comparison with conventional two-dimensional methods

AIMS

Although two-dimensional-dobutamine stress echocardiography (2D-DSE) is useful for the diagnosis of myocardial ischaemia, it requires the acquisition of multiple cross-sections at each stage. The introduction of new real-time three-dimensional echocardiography (RT3DE) offers rapid acquisition and 3D display of the entire left ventricle (LV). The purpose was to evaluate real-time three-dimensional-dobutamine stress echocardiography (RT3D-DSE) for the diagnosis of ischaemia using exercise (201)Tl single-photon emission computed tomography (SPECT) as the reference standard, in comparison with 2D-DSE.

METHODS AND RESULTS

We performed DSE in 56 consecutive patients who had undergone SPECT because of suspected ischaemia. 3D images by RT3DE were acquired from the apical window after the acquisition of cross-sectional images at every stage of 2D-DSE. Wall motion analysis in RT3DE was performed from anatomical images by cropping the acquired full volume data sets. Mean scanning time for adequate image acquisition at peak stress by RT3D-DSE was shorter than that by 2D-DSE (29+/-4 vs. 68+/-6 s, P<0.0001). RT3DE provided adequate images at success rate of 92% at rest and 89% at peak stress, whereas two-dimensional echocardiography did at 94 and 90%, respectively. The sensitivity, specificity, and accuracy of RT3D-DSE for the detection of coronary artery disease are 86, 80, and 82%, respectively. Those of 2D-DSE are 86, 83, and 84%, respectively. There were no significant differences in the sensitivity, specificity, and accuracy between these two methods (P=1.000).

CONCLUSION

RT3D-DSE offers rapid and simple acquisition of the entire LV wall motion and provides feasible and accurate assessment of myocardial ischaemia.

Relevance of tissue Doppler in the quantification of stress echocardiography for the detection of myocardial ischemia in clinical practice

In the present article we review the main published data on the application of Tissue Doppler Imaging (TDI) to stress echocardiography for the detection of myocardial ischemia. TDI has been applied to stress echocardiography in order to overcome the limitations of visual analysis for myocardial ischemia. The introduction of a new technology for clinical routine use should pass through the different phases of scientific assessment from feasibility studies to large multicenter studies, from efficacy to effectiveness studies. Nonetheless the pro-technology bias plays a major role in medicine and expensive and sophisticated techniques are accepted before their real usefulness and incremental value to the available ones is assessed. Apparently, TDI is not exempted by this approach : its applications are not substantiated by strong and sound results. Nonetheless, conventional stress echocardiography for myocardial ischemia detection is heavily criticized on the basis of its subjectivity. Stress echocardiography has a long lasting history and the evidence collected over 20 years positioned it as an established tool for the detection and prognostication of coronary artery disease. The quantitative assessment of myocardial ischemia remains a scientific challenge and a clinical goal but time has not come for these newer ultrasonographic techniques which should be restricted to research laboratories.

Early and long-term outcome of elective stenting of the infarct-related artery in patients with viability in the infarct-area: Rationale and design of the Viability-guided Angioplasty after acute Myocardial Infarction-trial (The VIAMI-trial)

Background

Although percutaneous coronary intervention (PCI) is becoming the standard therapy in ST-segment elevation myocardial infarction (STEMI), to date most patients, even in developed countries, are reperfused with intravenous thrombolysis or do not receive a reperfusion therapy at all. In the post-lysis period these patients are at high risk for recurrent ischemic events. Early identification of these patients is mandatory as this subgroup could possibly benefit from an angioplasty of the infarct-related artery.

Since viability seems to be related to ischemic adverse events, we initiated a clinical trial to investigate the benefits of PCI with stenting of the infarct-related artery in patients with viability detected early after acute myocardial infarction.

Methods

The VIAMI-study is designed as a prospective, multicenter, randomized, controlled clinical trial. Patients who are hospitalized with an acute myocardial infarction and who did not have primary or rescue PCI, undergo viability testing by low-dose dobutamine echocardiography (LDDE) within 3 days of admission. Consequently, patients with demonstrated viability are randomized to an invasive or conservative strategy. In the invasive strategy patients undergo coronary angiography with the intention to perform PCI with stenting of the infarct-related coronary artery and concomitant use of abciximab. In the conservative group an ischemia-guided approach is adopted (standard optimal care).

The primary end point is the composite of death from any cause, reinfarction and unstable angina during a follow-up period of three years.

Conclusion

The primary objective of the VIAMI-trial is to demonstrate that angioplasty of the infarct-related coronary artery with stenting and concomitant use of abciximab results in a clinically important risk reduction of future cardiac events in patients with viability in the infarct-area, detected early after myocardial infarction.

Coronary flow reserve of the angiographically normal left anterior descending coronary artery in patients with remote coronary artery disease

Coronary artery disease (CAD) has been suggested to alter coronary flow reserve (CFR; the ratio between hyperemic and baseline coronary flow velocities) not only in territories supplied by stenotic arteries but also in angiographically normal, remote regions. However, few data exist regarding the left anterior descending (LAD) coronary artery as the normal index artery. The influence of remote CAD on CFR of the angiographically normal LAD was evaluated with transthoracic Doppler ultrasound to measure CFR in the LAD during 90 seconds of venous adenosine infusion (140 microg/kg/min) in 122 subjects who were assigned to 1 group; group 1 comprised 49 controls without angiographically detectable CAD, and group 2 consisted of 73 patients with an angiographically normal LAD and remote CAD. Group 2 was divided into 4 subgroups: 16 patients with previous remote percutaneous coronary intervention (group 2A); 13 patients with significant remote stenosis (group 2B); 23 patients with previous remote myocardial infarction and percutaneous coronary intervention (group 2C); and 21 patients with previous remote myocardial infarction but no percutaneous coronary intervention (group 2D). CFR in the LAD was not significantly different in groups 1 and 2 (3.08 +/- 0.61 and 3.03 +/- 0.69, respectively, p = NS). Decreased ejection fraction and increased wall motion score index in patients with remote CAD (p < 0.00001) and multivessel CAD did not affect CFR in the LAD (group 2A 3.18 +/- 0.77; group 2B 3.05 +/- 0.65; group 2C 3.07 +/- 0.79; group 2D 2.86 +/- 0.50, respectively; F = 0.63, p = NS). In conclusion, CFR of an angiographically normal LAD is preserved in patients with remote CAD, even in the presence of previous remote myocardial infarction and wall motion abnormalities.

[Predictive significance of residual ischemia detected by the dobutamine stress-echocardiography test soon after the first uncomplicated myocardial infarction]

BACKGROUND

To evaluate the long-term prognostic value of dobutamine stress-echocardiography (ECG) test for new coronary events (new episodes of angina pectoris, cardiac-related deaths, and reinfarctions) early after the first uncomplicated myocardial infarction.

METHODS

Dobutamine stress-echocardiography tests were performed in all of 104 patients 10-20 days after the first myocardial infarction. Patients were followed-up for 36 (29 +/- 7) months. Kaplan-Meier cumulative survival curves were tested by Breslow test (Log Rank).

RESULTS

Two cardiac deaths (1.92%), nine nonfatal myocardial infarctions (8.65%), and three cases of recurrent angina pectoris (2.88%) occurred during the prospective follow-up. Cumulative survival curves showed that in patients with negative findings of dobutamine stress-echocardiography test, survival time without significant events was 35.31 months, while in the group with positive findings of dobutamine stress-echocardiography test it was 30.91 months (log Rank 7.22; p<0.01). Prognostic value of dobutamine stress-echocardiography test was analyzed by Cox regression model and was 2.92, meaning that the risk of significant events was 2.92 times higher in the group of patients with positive findings of dobutamine stress-echocardiography test.

CONCLUSION

Patients with negative findings of dobutamine stress-echocardiography test were with significantly higher possibility of surviving without significant events in comparison with the patients in whom the findings of dobutamine stress-echocardiography test were positive. In combination with clinical signs and ECG results, the results of dobutamine stress-echocardiography test improved prognostic value in the patients with the first uncomplicated myocardial infarction, and in that way influenced the strategy of their further treatment.

Usefulness of multidetector-row CT in the evaluation of reperfused myocardial infarction in a rabbit model

Objective

To evaluate the usefulness of multidetector-row computed tomography (CT) in the evaluation of reperfused myocardial infarction.

Materials and Methods

Eleven rabbits were subjected to 90-min occlusion of the left anterior descending coronary artery followed by reperfusion. Multidetector-row CT was performed 31 hours ± 21 after the procedure and pre- and post-contrast multiphase helical CT images were obtained up to 10 min after contrast injection. The animals were sacrificed after 30 days and histochemical staining of the resected specimens was perfomed with 2'3'5-triphenyl tetrazolium chloride (TTC).

Results

In all 11 cases, the areas of myocardial infarction demonstrated with TTC-staining were identified on the CT images and the lesions showed hypoenhancement on the early phases up to 62 sec and hyperenhancement on the delayed phases of 5 min and 10 min compared with normal myocardial enhancement. The percentage area of the lesion with respect to the left ventricle wall on CT was significantly correlated with that of the TTC-staining results (p < 0.001 for both early and delayed phase CT) according to the generalized linear model analysis. The areas showing hypoenhancement on early CT were significantly smaller than those with hyperenhancement on delayed CT (p < 0.0001).

Conclusion

Multidetector-row CT may be useful in the detection and sizing of reperfused myocardial infarction.

Pharmacologic stress echocardiography predicts total mortality early after acute myocardial infarction

OBJECTIVE

The aim of this multicenter, prospective, observational study was to assess the value of inducible ischemia in a large population of survivors of a first uncomplicated myocardial infarction (MI).

METHODS AND RESULTS

Pharmacologic stress echocardiography either with high-dose dipyridamole (0.84 mg/kg over 10 minutes) or high-dose dobutamine (up to 40 microg/kg over 3 minutes) (DET) was performed 9 +/- 10 days after a first acute uncomplicated MI in 1681 patients (1499 males; 57 +/- 10 years) with technically satisfactory rest echocardiographic study. Patients were followed up for a mean of 16 +/- 18 months (range: 1-122). DET was positive for myocardial ischemia in 884 (52.5%) and negative in 797 (47.5%) patients. During the follow-up there were 49 deaths for all-cause mortality (2.9% of the total population), 22 of which were cardiac; 62 (3.6%) nonfatal MIs; and 164 (9.7%) hospital readmissions for unstable angina. In all, 376 patients (22%) underwent coronary revascularization (bypass operation or angioplasty).

RESULTS

Hard events occurred in 71 of the 884 patients with positive and in 40 of the 797 patients with negative DET (8% vs 5%, P =.014). Using the Cox proportional hazards model, age (relative risk [RR] 1.07, 95% confidence interval [CI] 1.03-1.1), history of angina (RR 3.8, 95% CI 1.6-8.6), peak wall-motion score index (RR 2.2, 95% CI 1.1-4.4), and pharmacologic dose at ischemia (RR 1.5, 95% CI 1.04-2.3) were independent predictors of all-cause death.

CONCLUSIONS

In survivors of a first acute uncomplicated MI DET allows effective risk stratification on the basis of the presence, severity, and extent the induced ischemia.

Sonovue improves endocardial border detection and variability in assessing wall motion score and ejection fraction during stress echocardiography

BACKGROUND

Stress echocardiography is useful for assessing patients with coronary artery disease unable to undergo formal exercise testing. Considerable skill is required to avoid large intra- and inter-observer variability due to poor endocardial definition. Intravenous ultrasound contrast agents are now available which may improve this variability.

AIM

To study intravenous Sonovue in assessing wall motion score and ejection fraction (EF) during stress echocardiography.

METHODS

Thirty-eight patients undergoing arbutamine stress echocardiography for known or suspected coronary artery disease were studied. Echocardiographic analysis of wall motion score index, endocardial border detection (EBD) and EF was performed at rest and at peak stress before and after intravenous injection of Sonovue, by experienced and inexperienced observers.

RESULTS

All three observers noted an improvement in endocardial border definition following Sonovue (p=<0.001). At baseline, there was a significant difference in wall motion score index between experienced and inexperienced observers at rest (p=0.01) and at peak stress (p=0.001). Following Sonovue administration this was no longer significant (p=0.07, p=0.114). Intra-observer variability of end diastolic, end systolic volumes (ESV) and EF improved following contrast (p<0.05) at rest and during stress.

CONCLUSION

Sonovue significantly improved EBD and reduced intra-observer variability of EF at rest and during peak arbutamine infusion.

Intracoronary electrocardiogram and angina pectoris during percutaneous coronary interventions as an assessment of myocardial viability: Comparison with low-dose dobutamine echocardiography

The aims of this study were to evaluate the diagnostic value of intracoronary electrocardiogram (ECG) and presence of angina pectoris during percutaneous coronary interventions in the prediction of myocardial viability assessed by low-dose dobutamine echocardiography (LDDE). Seventy-one patients (60 men; mean age, 54 +/- 11 years) with recent Q-wave MI and angiographically documented regional wall motion abnormality in the presence of a significant (>/= 70%) nonocclusive stenosis of the infarct-related vessel who were referred for angioplasty were prospectively included in the study. The intracoronary ECG was recorded using coronary angioplasty guidewire. Significant ST segment elevation was defined as a new or worsening ST segment elevation of >/= 0.1 mV at 80 msec after the J-point. Angina pectoris was noted as present or absent during balloon inflation. All patients underwent LDDE for viability assessment. Significant ST segment elevation in the intracoronary ECG and chest pain were observed in 56 (78.9%) and 49 (69%) of the 71 patients. Viability was present on LDDE in 52 (92.9%) of 56 patients with and 3 (20%) of 15 without ST segment elevation. Viability was detected in 45 (91.8%) of 49 patients with and 10 (45.4%) of 22 without angina pectoris during balloon occlusion. The sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of ST segment elevation for viability were 94.5%, 75%, 92.9%, 80%, and 90.1%, respectively. The sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of angina pectoris for viability were 81.8%, 75%, 91.8%, 54.5%, and 80.3%, respectively. The present study demonstrated that a simple assessment of ST segment elevation in the intracoronary ECG or angina pectoris during coronary angioplasty can be used to assess myocardial viability identified by LDDE in patients with previous MI.

Enoximone very low-dose dobutamine stress echocardiography: a new test for detecting viability in severe myocardial dysfunction after acute myocardial infarction

Relying on the synergistic action on contractility of enoximone and dobutamine when concomitantly infused, 25 patients with their first acute Q-wave anterior myocardial infarctions underwent conventional low-dose dobutamine echocardiography (LDE) and enoximone very-LDE to assess myocardial viability in severely dysfunctioning areas. Images were recorded at peak of pharmacodynamic effect of drugs and 4 months after revascularization. At peak-dose stage of LDE and enoximone very-LDE the regional infarct zone wall-motion score significantly decreased from the basal value of 25.6 +/- 2.9 to 16 +/- 6.0 (P <.001) and to 14.5 +/- 5.2 (P <.001), respectively. A high correlation was found by comparing the wall-motion score of each patient calculated at peak effect of combined drug administration with follow-up values (r(s) = 0.9). Enoximone very-LDE has proven to be a new test useful to evaluate viability in asynergic segments especially when the results of conventional tests are questionable.