Myocardial wall thickness predicts recovery of contractile function after primary coronary intervention for acute myocardial infarction

Clinical impact of multimodality assessment of myocardial viability

Coronary artery disease (CAD) is a prevalent cause of left ventricular dysfunction. Nevertheless, effective elective revascularization, particularly surgical revascularization, can enhance long-term outcomes and, in selected cases, global left ventricular contractility. The assessment of myocardial viability and scars is still relevant in guiding treatment decisions and selecting patients who are likely to benefit most from blood flow restoration. Although the most recent randomized studies challenge the notion of "hibernating myocardium" and the clinical usefulness of assessing myocardial viability, the advancement of imaging techniques still renders this assessment valuable in specific situations. According to the guidelines of the European Society of Cardiology, non-invasive stress imaging may be employed to define myocardial ischemia and viability in patients with CAD and heart failure before revascularization. Currently, several non-invasive imaging techniques are available to evaluate the presence and extent of viable myocardium. The selection of the most suitable technique should be based on the patient, clinical context, and resource availability. This narrative review evaluates the characteristics of available imaging modalities for assessing myocardial viability to determine the most appropriate therapeutic strategy.

Myocardial Viability Testing to Guide Coronary Revascularization

Left ventricular dysfunction remains one of the best prognostic determinants of survival in patients with coronary artery disease. Revascularization has been shown to improve survival compared with medical therapy alone. Viability testing can help direct patients who will benefit the most from revascularization. Single-photon emission computed tomography, dobutamine stress echo, cardiac MRI, and PET imaging with F18-fluorodeoxyglucose are the most common modalities for assessing myocardial viability. Viability testing can help differentiate which patients benefit most from chronic total occlusion interventions.

Safety and efficacy of high-dose adeno-associated virus 9 encoding sarcoplasmic reticulum Ca(2+) adenosine triphosphatase delivered by molecular cardiac surgery with recirculating delivery in ovine ischemic cardiomyopathy

OBJECTIVE

Therapeutic safety and efficacy are the basic prerequisites for clinical gene therapy. We investigated the effect of high-dose molecular cardiac surgery with recirculating delivery (MCARD)-mediated adeno-associated virus 9 (AAV9)/sarcoplasmic reticulum Ca(2+) adenosine triphosphatase (SERCA2a) gene delivery on clinical parameters, oxidative stress, humoral and cellular immune responses, and cardiac remodeling.

METHODS

Ischemic cardiomyopathy was generated in a sheep model. The sheep were assigned to 1 of 2 groups: control (n = 10) and study (MCARD, n = 6). The control group underwent no intervention and the study group received 10(14) genome copies of AAV9/SERCA2a 4 weeks after infarction.

RESULTS

Our ischemic model produced reliable infarcts leading to heart failure. The baseline ejection fraction in the MCARD group was 57.6% ± 1.6% versus 61.2% ± 1.9% in the control group (P > .05). At 12 weeks after infarction, the MCARD group had superior left ventricular function compared with the control group: stroke volume index, 46.6 ± 1.8 versus 35.8 ± 2.5 mL/m(2) (P < .05); ejection fraction, 46.2% ± 1.9% versus 38.7% ± 2.5% (P < .05); and left ventricular end-systolic and end-diastolic dimensions, 41.3 ± 1.7 versus 48.2 ± 1.4 mm and 51.2 ± 1.5 versus 57.6 ± 1.7 mm, respectively (P < .05). The markers of oxidative stress were significantly reduced in the infarct zone in the MCARD group. No positive T-cell-mediated immune response was seen in the MCARD group at any point. Myocyte hypertrophy was also significantly attenuated in the MCARD group compared with the control group.

CONCLUSIONS

Cardiac overexpression of the SERCA2a gene by way of MCARD is a safe therapeutic intervention. It significantly improves left ventricular function, decreases markers of oxidative stress, abrogates myocyte hypertrophy, arrests remodeling, and does not induce a T-cell-mediated immune response.

Clinical usefulness of SonoVue contrast echocardiography: the Thoraxcentre experience

Although other imaging techniques, such as magnetic resonance imaging and computer tomography, are becoming more and more important in cardiology, two-dimensional echocardiography is still the most used technique in clinical cardiology. Quantification of left ventricular function and dimensions is important because therapeutic strategies, for example implanting an ICD after myocardial infarction, are based on ejection fraction measurements. Because of the sometimes low quality of echocardiographic images we started to use an ultrasound contrast agent and in this article we describe our experiences with SonoVue, a second-generation contrast agent, over a threeyear period in the Thoraxcentre. (Neth Heart J 2007;15:55-60.).

Protective effect of Chinese herbs for supplementing qi, nourishing yin and activating blood circulation on heart function of patients with acute coronary syndrome after percutaneous coronary intervention

OBJECTIVE

To investigate the effects of Chinese herbs for supplementing qi, nourishing yin and activating blood circulation on heart function of patients with acute coronary syndrome (ACS) after successful percutaneous coronary intervention (PCI).

METHODS

One hundred patients with ACS after successful PCI were randomly assigned to a Western medicine (WM) treatment group (WMG) and a combined treatment group (CMG) treated by Chinese herbs for supplementing qi, nourishing yin and activating blood circulation, besides Western medicine treatment, with 50 cases in each group. Both treatment courses were 6 months. The followup was scheduled at baseline, 6 months and 1 year after PCI, and New York Heart Association (NYHA) functional class, Chinese medicine (CM) symptom scores, blood stasis syndrome scores, and major adverse cardiovascular events (MACE) were observed, serum levels of N-terminal pro-brain natriuretic peptide (NT-proBNP) and hyper-sensitivity C-reactive protein (Hs-CRP) were measured, an echocardiogram was conducted to examine left ventricular ejection fraction (LVEF), left ventricular end-diastolic volume (LVEDV), left ventricular end-systolic volume (LVESV), inter-ventricular septal thickness (IVST), left ventricular posterior wall thickness (LVPWT), and ventricular wall motion index (VWMI).

RESULTS

Compared with the baseline, LVEF significantly increased (P<0.01), and CM symptom scores, blood stasis syndrome scores, VWMI, LVEDV, LVESV, NT-proBNP, and Hs-CRP all decreased (P<0.01) in both groups at 6 months and at 1 year after PCI. There were no significant differences in all the above parameters at 1 year vs those at 6 months after PCI (P>0.05). VWMI, LVEDV, LVESV, NT-proBNP, Hs-CRP, LVEF, and CM symptom and blood stasis syndrome scores were all improved obviously in CMG than those in WMG (P<0.05 or P<0.01) at 6 months and at 1 year after PCI. There were no significant differences in NYHA functional class between CMG and WMG at different follow-up timepoints; it was notable that value was 0.054 when comparing the cases of NYHA functional class between the two groups at 1-year follow-up. During the 1-year follow-up, 3 MACE and 11 MACE occurred in CMG and WMG, respectively; the MACE rate in CMG was lower than that in WMG (6% vs 22%, P<0.05).

CONCLUSION

Chinese herbs for supplementing qi, nourishing yin and activating blood circulation could improve heart function, reduce the CM symptom scores and blood stasis syndrome scores, and decrease the incidence of MACE in patients with ACS after successful PCI.

Dor procedure for dyskinetic anteroapical myocardial infarction fails to improve contractility in the border zone

BACKGROUND

Endoventricular patch plasty (Dor) is used to reduce left ventricular volume after myocardial infarction and subsequent left ventricular remodeling.

METHODS AND RESULTS

End-diastolic and end-systolic pressure-volume and Starling relationships were measured, and magnetic resonance images with noninvasive tags were used to calculate 3-dimensional myocardial strain in 6 sheep 2 weeks before and 2 and 6 weeks after the Dor procedure. These experimental results were previously reported. The imaging data from 1 sheep were incomplete. Animal specific finite element models were created from the remaining 5 animals using magnetic resonance images and left ventricular pressure obtained at early diastolic filling. Finite element models were optimized with 3-dimensional strain and used to determine systolic material properties, T(max,skinned-fiber), and diastolic and systolic stress in remote myocardium and border zone. Six weeks after the Dor procedure, end-diastolic and end-systolic stress in the border zone were substantially reduced. However, although there was a slight increase in T(max,skinned-fiber) in the border zone near the myocardial infarction at 6 weeks, the change was not significant.

CONCLUSIONS

The Dor procedure decreases end-diastolic and end-systolic stress but fails to improve contractility in the infarct border zone. Future work should focus on measures that will enhance border zone function alone or in combination with surgical remodeling.

Adverse reactions after the use of sulphur hexafluoride (SonoVue) echo contrast agent

The aim of the present study was to analyse the adverse effects of SonoVue echo contrast in a consecutive series of 352 cardiac patients during a 4-year period. During 352 consecutive cardiac SonoVue studies, seven patients (2.0%) experienced adverse effects. Four patients (1.1%) had mild allergic reactions causing skin erythema and mild sinus tachycardia, and three patients (0.9%) experienced a severe allergic reaction resulting in (nonfatal) shock. The reported incidence of adverse effects of SonoVue echo contrast in this consecutive series of cardiac patients seems markedly higher than those reported in a company postmarketing analysis.

Predictors and time-related impact of distal embolization during primary angioplasty

AIMS

We sought to identify predictors of distal embolization (DE) occurring during primary percutaneous coronary intervention (p-PCI) as well as to assess its impact on both myocardial reperfusion and necrosis, according to time-to-treatment.

METHODS AND RESULTS

Clinical and angiographic characteristics were prospectively assessed in 400 consecutive patients who underwent p-PCI, in order to identify predictors of DE. The impact of DE on Thrombolysis in Myocardial Infarction (TIMI) flow, myocardial blush, and troponin I (TnI) was assessed according to symptom onset-to-balloon time. DE occurred in 64 (16%) patients and did not change with time-to-treatment (P = 0.87). The occlusion pattern of infarct-related artery (IRA), treatment of right coronary artery, higher TIMI thrombus score, longer lesion, and large IRA diameter were predictors of DE. The rate of TIMI 0/1 and myocardial blush 0/1 was higher in patients exhibiting DE when time-to-treatment was < or =6 h (P < 0.0001), while TnI was higher in patients with DE when time-to-treatment was <3 h.

CONCLUSION

DE during p-PCI occurs more often in the presence of high thrombus burden lesion. It reduces the effectiveness of myocardial reperfusion within 6 h and enhances myocardial damage within 3 h after symptom onset. Afterwards, it does not affect myocardial reperfusion or the extent of myocardial damage.

Evaluation of left ventricular function three years after percutaneous recanalization of chronic total coronary occlusions

We investigated early and late effects of percutaneous revascularization for chronic total coronary occlusion on left ventricular (LV) function and volumes. Magnetic resonance imaging was performed in 21 patients before and 5 months and 3 years after recanalization. Global LV function and volumes and segmental wall thickening (SWT) were quantified on cine images. The 2 viability indexes used were the transmural extent of infarction (TEI) on delayed contrast enhancement images and end-diastolic wall thickness at baseline. Significant decreases in mean end-diastolic (86 +/- 14 to 78 +/- 15 ml/m2; p = 0.02) and mean end-systolic volume indexes (35 +/- 13 to 30 +/- 13 ml/m2; p = 0.03) were observed 3 years after recanalization. Mean ejection fraction tended to improve (60 +/- 9% to 63 +/- 11%; p = 0.11). SWT significantly increased at 5-months' follow-up (p <0.001), and an additional improvement was found at 3 years' (p = 0.04) follow-up in segments with TEI <25%. In segments with TEI of 25% to 75%, SWT was unchanged at 5-month follow-up (p = 0.89), but improved at 3 years (p = 0.04). SWT was unchanged in segments with transmural scars. For segmental functional recovery, TEI was a better predictor than end-diastolic wall thickness at baseline (odds ratio 5.6, 95% confidence interval 1.5 to 21.1, p = 0.01 vs odds ratio 2.5, 95% confidence interval 0.7 to 8.3, p = 0.14). In conclusion, a positive effect on LV remodeling and ejection fraction was observed up to 3 years after recanalization. Both early and late improvements in regional LV function were observed in the perfusion territory of chronic total coronary occlusion and were related to the transmural extent of infarction on pretreatment magnetic resonance imaging.

Evolution of 5 cardiovascular magnetic resonance-derived viability indexes after reperfused myocardial infarction

BACKGROUND

The objective of this study was to evaluate the simultaneous evolution of 5 cardiovascular magnetic resonance-derived myocardial viability indexes.

METHODS

We studied 72 patients with a first ST-elevation myocardial infarction and sustained TIMI 3 flow. In the first week and in the sixth month of the study, using cardiovascular magnetic resonance imaging, we determined wall thickening (WT) and the following viability indexes: wall thickness, WT with low-dose dobutamine, microvascular perfusion in first-pass imaging, microvascular obstruction in late-enhancement imaging, and transmural extent of necrosis.

RESULTS

In 250 dysfunctional segments, the evolution outcomes for the viability indexes were as follows: (1) wall thickness thinned (8.6 +/- 2.9 versus 7.7 +/- 3 mm, P < .001), (2) WT with low-dose dobutamine improved (1.5 +/- 1.9 versus 2.6 +/- 3 mm, P < .001), (3) the number of segments showing abnormal microvascular perfusion in first-pass imaging decreased (22% versus 7%, P < .001), (4) the number of segments showing microvascular obstruction in late-enhancement imaging decreased (14% versus 2%, P < .001), and (5) the transmural extent of necrosis remained stable throughout follow-up (56% +/- 40% versus 54% +/- 39%, P = .3).

CONCLUSIONS

After reperfused myocardial infarction, dynamic changes in wall thickness, contractile reserve, microvascular perfusion, and microvascular obstruction take place. These changes may affect their accuracy as viability indexes early after myocardial infarction. The transmural extent of necrosis does not vary, however.

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.

Myocardial Perfusion After Percutaneous Transluminal Septal Myocardial Ablation as Assessed by Myocardial Contrast Echocardiography in Patients with Hypertrophic Obstructive Cardiomyopathy

Microvascular dysfunction in hypertrophic obstructive cardiomyopathy (HOCM) depends on a complex interplay of functional and anatomic mechanisms. We used myocardial contrast echocardiography in 16 consecutive patients with HOCM (mean age 49 +/- 15 years; 11 men) referred for percutaneous transluminal septal myocardial ablation to assess myocardial perfusion before and 6 months after the procedure. Myocardial contrast echocardiography was performed using real-time imaging during intravenous injection of SonoVue. Myocardial blood velocity (beta) and a semiquantitative assessment of blood volume were obtained in the apical 4-chamber views at midapical septum. Twelve healthy individuals served as control subjects. In patients with HOCM, beta was lower either before (0.17 +/- 0.04 vs 0.50 +/- 0.34 s(-1), P = .006) or after (0.23 +/- 0.07 vs 0.50 +/- 0.34 s(-1), P = .02) successful percutaneous transluminal septal myocardial ablation compared with control subjects. A patchy perfusion pattern was seen in all the patients with HOCM either before or after the procedure. In patients with HOCM percutaneous transluminal septal myocardial ablation improves, but does not normalize microvascular function.

Assessment of resting perfusion defects in patients with acute myocardial infarction: comparison of myocardial contrast echocardiography, combined first-pass/delayed contrast-enhanced magnetic resonance imaging and 99mTC-sestamibi SPECT

BACKGROUND

Information on the accuracy of both magnetic resonance imaging (MRI) and myocardial contrast echocardiography (MCE) for the identification of perfusion defects in patients with acute myocardial infarction is limited. We evaluated the accuracy of MRI and MCE, using Single Photon Emission Computed Tomography (SPECT) imaging as reference technique.

METHODS

Fourteen consecutive patients underwent MCE, MRI and 99mTc-MIBI SPECT after acute myocardial infarction to assess myocardial perfusion. MCE was performed by Harmonic Power Angio Mode, with end-systolic triggering 1:4, using i.v. injection of Levovist. First-pass and delayed enhancement MRI was obtained after i.v administration of Gadolinium-DTPA. At MCE, homogeneous perfusion was considered as normal and absent or "patchy" perfusion as abnormal. At MRI, homogenous contrast enhancement was defined as normal whereas hypoenhancement at first-pass followed by hyperenhancement or persisting hypoenhancement in delayed images was defined as abnormal.

RESULTS

At MCE 153 (68%) of segments were suitable for analysis compared to 220 (98%) segments at MRI (p<0.001). Sensitivity, specificity and accuracy of MCE for segmental perfusion defects in these 153 segments were 83, 73 and 77%, respectively. Sensitivity, specificity and accuracy of MRI were 63, 82, and 77%, respectively. MCE and MRI showed a moderate agreement with SPECT (k: 0.52 and 0.46, respectively). The agreement between MCE and MRI was better (k: 0.67) that the one of each technique with SPECT.

CONCLUSION

MCE and MRI may be clinically useful in the assessment of perfusion defects in patients with acute myocardial infarction, even thought MCE imaging may be difficult to obtain in a considerable proportion of segments when the Intermittent Harmonic Angio Mode is used.

Usefulness of a Comprehensive Cardiovascular Magnetic Resonance Imaging Assessment for Predicting Recovery of Left Ventricular Wall Motion in the Setting of Myocardial Stunning

OBJECTIVES

We sought to evaluate the usefulness of a comprehensive assessment of four cardiovascular magnetic resonance imaging (CMR)-derived myocardial viability indexes in the setting of myocardial stunning.

BACKGROUND

Cardiovascular magnetic resonance imaging allows the simultaneous assessment of several viability indexes.

METHODS

We studied 40 patients with a first ST-segment elevation myocardial infarction (MI) and an open infarct-related artery. At the first week, using CMR, wall motion (WM), and four viability indexes were determined: wall thickness, WM improvement with low-dose dobutamine, perfusion, and transmural extent of necrosis. We created a comprehensive score based on the presence and the relative power of these viability indexes for predicting normal WM at the sixth month.

RESULTS

Of 153 dysfunctional segments at the first week, 59 (39%) exhibited normal WM at the sixth month. According to the odds ratio of viability indexes for predicting normal WM, we developed a five-level predictive score. The proportions of segments showing normal WM at sixth month were as follows; Level 1 (0 indexes): 0 of 13 (0%); Level 2 (normal thickness and/or perfusion): 14 of 82 (17%); Level 3 (dobutamine response): 5 of 11 (45%); Level 4 (non-transmural necrosis): 20 of 26 (77%); Level 5 (non-transmural necrosis and dobutamine response): 20 of 21 (95%), p < 0.0001 for the trend. These proportions were similar in a matched prospective validation group comprising 16 patients (0%, 18%, 62%, 77%, and 90% for levels 1 to 5, respectively, p < 0.0001 for the trend).

CONCLUSIONS

A comprehensive analysis of the four more widely used CMR-derived viability indexes is useful for predicting late systolic function after myocardial infarction.