Myocardial strain of the left ventricle by speckle tracking echocardiography: From physics to clinical practice.

Speckle tracking echocardiography (STE) is a reliable imaging technique of recognized clinical value in several settings. This method uses the motion of ultrasound backscatter speckles within echocardiographic images to derive myocardial velocities and deformation parameters, providing crucial insights on several cardiac pathological and physiological processes. Its feasibility, reproducibility, and accuracy have been widely demonstrated, being myocardial strain of the various chambers inserted in diagnostic algorithms and guidelines for various pathologies. The most important parameters are Global longitudinal strain (GLS), Left atrium (LA) reservoir strain, and Global Work Index (GWI): based on large studies the average of the lower limit of normality are -16%, 23%, and 1442 mmHg%, respectively. For GWI, it should be pointed out that myocardial work relies primarily on non-invasive measurements of blood pressure and segmental strain, both of which exhibit high variability, and thus, this variability constitutes a significant limitation of this parameter. In this review, we describe the principal aspects of the theory behind the use of myocardial strain, from cardiac mechanics to image acquisition techniques, outlining its limitation, and its principal clinical applications: in particular, GLS have a role in determine subclinical myocardial dysfunction (in cardiomyopathies, cardiotoxicity, target organ damage in ambulatory patients with arterial hypertension) and LA strain in determine the risk of AF, specifically in ambulatory patients with arterial hypertension.

Validation of Transesophageal Echocardiographic In Vitro Measurements for Bioprosthetic Aortic Valves: Implications for Percutaneous Valve-in-Valve Therapy.

BACKGROUND: Percutaneous valve-in-valve therapy has become an important treatment option for failing bioprosthetic heart valves. Accurate assessment of valve internal diameter (ID) is essential for effective and safe treatment. These data may not be available in an individual patient, or the manufacturer-supplied dimensions may be incorrect because they do not allow for the space occupied by valve leaflet material. METHODS: In total, 2,332 two-dimensional and three-dimensional transesophageal echocardiographic in vitro measurements were performed using both Philips iE33 and GE Vivid E9 systems with a range of system settings on 53 bioprosthetic valves in all available sizes. Two-dimensional echocardiographic ID measurements were made in two orthogonal planes at the level of the sewing ring, and similar three-dimensional measurements were generated from multiplane reconstructions. They were compared with both manufacturer-supplied valve ID (MID) and the true ID (TID) measured with Hegar dilators. RESULTS: Both the iE33 and the Vivid 9 provided comparable valve ID measurements. TID was statistically significantly smaller than MID (P < .001). All echocardiographic measurements were closer to TID than to MID. Two-dimensional measurements were closest to TID because of higher spatial resolution. CONCLUSIONS: Transesophageal echocardiographic valve ID measurements compare well with TID, which is overestimated by MID. These findings have potentially important implications for valve-in-valve procedures because an inaccurate measurement of TID might lead to the wrong choice of implanted valve.

Incidence and predictors of early left ventricular thrombus after ST-elevation myocardial infarction in the contemporary era of primary percutaneous coronary intervention.

The aim of this study was to define the incidence of left ventricular thrombus (LVT) and its predictors in the contemporary era of primary percutaneous intervention (pPCI) and contrast echocardiography. We retrospectively analyzed 1,059 patients presenting with ST-elevation myocardial infarction (STEMI) to our tertiary cardiac center and treated with pPCI. Preprocedural pharmacology and procedural technique (including access route, the use of drug-eluting stents, and thrombectomy) were at the operators' discretion. Transthoracic echocardiography was performed before discharge; echo contrast agent was used when appropriate. LVT was detected in 42 subjects (4%). There were no significant differences in baseline demographics or pre-PCI clinical features between the 2 groups. Post-treatment, mean ejection fraction (EF) in patients with LVT was 35±8.4% and in those without LVT was 47±10%, p<0.001. Thirty-seven patients (88%) in the LVT group presented with an anterior STEMI versus 471 patients (42%) in the without LVT group (p<0.001). Apical akinesis was noted in all patients with LVT irrespective of the principal location of the MI. Multivariate analysis predictors of LVT were reduced EF, anterior site of MI, and the use of platelet glycoprotein IIb/IIIa inhibitors. After diagnosis of LVT, patients were treated with warfarin for 3 to 6 months. No significant difference in mortality was detectable at discharge between the 2 groups. In conclusion, in the contemporary era of pPCI, the incidence of LVT in patients with STEMI is significantly lower than that of the previous (thrombolysis) literature. The early presence of LVT is more likely in patients with anterior STEMI (involving the apex) and reduced EF.

Pocket-size imaging device: effectiveness for ward-based transthoracic studies.

AIMS: Pocket-size imaging devices (PSID) are now available; their potential role in a hospital environment has been investigated but still remains undefined. METHODS AND RESULTS: We evaluated the effectiveness of PSID in 92 patients referred for bedside transthoracic echocardiogram (TTE). Patients were included where there was a focused clinical question: quantification of left ventricular function (LVF); presence of regional wall motion abnormalities (RWMA); evidence of pericardial effusion, exclusion of significant valve pathology. Each patient underwent an echocardiography evaluation using PSID and TTE. In 83 patients [k = 90%, 95% CI (82.2-95.4)], it was possible to answer the clinical question by PSID examination alone. There was agreement between the findings of PSID and TTE in 86 cases [79%; k = 47%, 95% CI (12.8-82.0)], in three cases, the clinical question was not answered by both modalities. When the clinical question was focused on LVF, the agreement was excellent [k = 96%, 95% CI (95.3-97.9)], as was the agreement in the detection of RWMA [k = 94.57%, 95% CI (82.4-95.1)]. There was also good concordance in the detection of valve pathology and pericardial effusion. Using PSID, the reduction in the scanning and reporting time was 66%. The cost-effectiveness analysis produced very favourable results: with PSE, we obtained an overall cost saving per scan of 76%, compared with TTE. CONCLUSION: This study demonstrates that PSID can provide a valuable alternative to TTE in the presence of focused clinical questions and can provide an efficient way of delivering a ward-based transthoracic echo service.

The additive value of three-dimensional derived left atrial volume and carotid imaging in dobutamine stress echocardiography.

AIMS: to evaluate whether the three-dimensional (3D) left atrial volume index (LAVI) and/or the presence of carotid plaques (CP) can predict the result of dobutamine stress echocardiography (DSE), thereby aiding interpretation. METHODS AND RESULTS: we studied 130 patients (52 male, mean age 63 ± 11 years) with normal resting wall motion (WM) undergoing DSE. All patients had the end-systolic 2D and 3D LAVI measured, as well as bilateral carotid scanning. DSE was reported as abnormal in 50 (38.5%) patients. 3D end-systolic LAVI measurements were significantly higher (31.5 ± 8.2 vs 27.4 ± 7.4 mL/m(2), P = 0.004) in those with an abnormal DSE. The two groups did not differ significantly on the 2D derived maximum LAVI measurements (36.2 ± 9.5 vs 34.2 ± 11.2, P = 0.299) and the presence of plaques in the carotid arteries (89.1 vs. 76.2%, P = 0.100). Receiver operating characteristic curves were created to define cut-offs that could predict the DSE result for the 3D LAVI. A 3D LAVI of >24.5 mL/m(2) had a sensitivity of 80% for predicting an abnormal DSE, whereas a value of >36.0 mL/m(2) had a specificity of 93% for the same cause. Intra-observer (r = 0.997, P < 0.0001) and inter-observer (r = 0.961, P < 0.0001) variability for 3D LAVI measurements was found to be excellent. CONCLUSION: three-dimensional (but not 2D) assessment of LAVI may offer additional information in predicting the result of DSE. Carotid scanning did not offer additional information for the same cause.

Long-term effectiveness of early administration of glycoprotein IIb/IIIa agents to real-world patients undergoing primary percutaneous interventions: results of a registry study in an ST-elevation myocardial infarction network.

AIMS: To evaluate the clinical impact of early administration of glycoprotein IIb/IIIa agents (IIb/IIIa agents) in the context of a dedicated hub and spoke network allowing very prompt pharmacological/mechanical interventions. METHODS AND RESULTS: Using a prospective database, we conducted a cohort study of ST-elevation myocardial infarction (STEMI) patients (n = 1124) undergoing primary percutaneous coronary interventions (PPCIs) and IIb/IIIa agents administration (period, 2003-2006). Comparisons were planned between patients receiving early IIb/IIIa agents administration (in hub/spoke centre emergency departments or during ambulance transfer; early group, n = 380) or delayed administration (in the catheterization laboratory; late group, n = 744). The primary outcome measure was long-term overall mortality/re-infarction. Baseline characteristics of the two groups were largely comparable. Angiographically, early group patients more often achieved pre-PPCI TIMI Grade 2-3 and TIMI Grade 3 flow. Clinically, the early administration group experienced lower 2-year risk of unadjusted mortality/re-infarction (17 vs. 23%; P = 0.01). After adjustment for potential confounders, early administration was associated with favourable outcome in the overall population (HR = 0.71, P = 0.03) and in high-risk subgroups (TIMI risk index >25, HR = 0.64, P = 0.02; Killip class >1, HR = 0.54, P = 0.01). CONCLUSION: In patients treated by PPCI within a STEMI network setting, early administration of IIb/IIIa agents may provide long-term clinical benefits. Notably, these results appeared magnified in high-risk patients.

Comparison between coronary angioplasty and coronary artery bypass surgery for the treatment of unprotected left main coronary artery stenosis (the Bologna Registry).

Although great interest exists in the relative efficacy of coronary artery bypass grafting (CABG) versus percutaneous coronary intervention (PCI) for the treatment of unprotected left main coronary artery stenosis, data comparing the 2 strategies are scant. Furthermore, no comparison has ever been performed between CABG and drug-eluting stents in this setting. From January 2002 to June 2005, 154 patients with unprotected left main coronary artery stenosis underwent CABG and 157 underwent PCI. Ninety-four patients received a drug-eluting stent in the left main artery. After a median follow-up of 430 days, the rate of mortality, acute myocardial infarction, and target lesion revascularization was 12.3%, 4.5%, and 2.6%, respectively, in the CABG group and 13.4%, 8.3%, and 25.5%, respectively, in the PCI group (death and myocardial infarction p = NS, target lesion revascularization p = 0.0001). Although patients treated with drug-eluting stents had a 25% relative risk reduction in the rate of death, myocardial infarction, and target lesion revascularization compared with patients treated with bare stents, event-free survival was still better for patients treated with CABG. In the multivariate analysis, age >or=70 years, New York Heart Association classes III and IV, acute coronary syndromes, and peripheral vascular disease were the only independent predictors of mortality. In conclusion, our results have indicated that at long-term follow-up no difference exists in the rate of mortality and myocardial infarction between PCI and CABG for the treatment of unprotected left main coronary artery stenosis. However, the rate of target lesion revascularization was higher in the PCI group.

Preprocedural levels of C-reactive protein and leukocyte counts predict 9-month mortality after coronary angioplasty for the treatment of unprotected left main coronary artery stenosis.

BACKGROUND: An accurate preprocedural risk stratification scheme for patients with unprotected left main coronary artery (ULMCA) stenosis who are undergoing coronary stenting is lacking. We examined the predictive value of preprocedural levels of C-reactive protein (CRP), fibrinogen, and leukocyte counts with respect to 9-month clinical outcomes after stenting of the ULMCA stenosis. METHODS AND RESULTS: Levels of CRP, fibrinogen, and leukocyte count were prospectively measured in 83 patients undergoing stenting of the ULMCA. A drug-eluting stent was used in 42 patients, and a bare metal stent was used in 41. The end point of the study was death and the combination of death and myocardial infarction (MI). By the 9-month follow-up, there were 11 deaths (13%), 7 MIs (8%), and 16 target lesion revascularizations (19%). Death and death/MI occurred in 19% and 31%, respectively, of 59 patients with high serum levels of CRP (>3 mg/L) but in none of 24 patients with normal CRP levels (for death, P=0.02; for death/MI, P=0.006). In multivariate analysis, the highest tertiles of CRP level (P=0.028) and leukocyte count (P=0.002) were the only independent predictors of death. The highest tertiles of CRP level (P=0.002) and leukocyte count (P=0.002) and acute coronary syndromes (P=0.05) were the only independent predictors of the combined end point death/MI. CONCLUSIONS: Elevated preprocedural levels of CRP indicate an increased risk of death and death/MI after ULMCA stenting. Inflammatory risk assessment in patients with ULMCA stenosis may be useful for selecting patients for percutaneous coronary interventions with very low risk.