Left ventricular function and infarct size 20 months after primary angioplasty for acute myocardial infarction

Long-term safety and sustained left ventricular recovery: long-term results of percutaneous left ventricular support with Impella LP2.5 in ST-elevation myocardial infarction

AIMS

Mechanical left ventricular (LV) unloading may reduce infarct size when combined with primary percutaneous coronary intervention (PCI) in patients with ST-elevation myocardial infarction (STEMI). The Impella LP2.5 is a novel percutaneous left ventricular assist device. Although the short-term safety and feasibility of this device have been demonstrated, the long-term effects are unknown. The purpose of the current study was to evaluate the long-term effects of the Impella LP2.5 support on the aortic valve and left ventricular ejection fraction (LVEF).

METHODS AND RESULTS

In 2006, 10 patients with anterior STEMI received 3-day support with the Impella LP2.5 after PCI. The control group consisted of 10 comparable patients, treated according to routine care. For the current study, echocardiography was performed and adverse events were recorded. Mean duration of follow-up was 2.9±0.6 years in the Impella group and 3.0±0.3 years in the control group. No differences in aortic valve abnormalities and LVEF were demonstrated between the groups; nevertheless, LVEF increase from baseline was significantly greater in Impella-treated patients (23.6±8.9% versus 6.7±7.0%, P=0.008).

CONCLUSIONS

Three-day support with the Impella LP2.5 is not associated with adverse effects on the aortic valve at long-term follow-up. LVEF was similar in both groups; however, recovery was significantly greater in the Impella group.

Efficacy and safety of immediate angioplasty versus ischemia-guided management after thrombolysis in acute myocardial infarction in areas with very long transfer distances results of the NORDISTEMI (NORwegian study on DIstrict treatment of ST-elevation myocardial infarction)

OBJECTIVES

The goal of this study was to compare a strategy of immediate transfer for percutaneous coronary intervention (PCI) with an ischemia-guided approach after thrombolysis in patients with very long transfer distances to PCI.

BACKGROUND

Thrombolysis remains the treatment of choice in ST-segment elevation myocardial infarction (STEMI) when primary PCI cannot be performed within 90 to 120 min. The optimal treatment after thrombolysis is still unclear.

METHODS

A total of 266 patients with acute STEMI living in rural areas with more than 90-min transfer delays to PCI were treated with tenecteplase, aspirin, enoxaparin, and clopidogrel and randomized to immediate transfer for PCI or to standard management in the local hospitals with early transfer, only if indicated for rescue or clinical deterioration. The primary outcome was a composite of death, reinfarction, stroke, or new ischemia at 12 months, and analysis was by intention to treat.

RESULTS

The primary end point was reached in 28 patients (21%) in the early invasive group compared with 36 (27%) in the conservative group (hazard ratio: 0.72, 95% confidence interval: 0.44 to 1.18, p = 0.19). The composite of death, reinfarction, or stroke at 12 months was significantly reduced in the early invasive compared with the conservative group (6% vs. 16%, hazard ratio: 0.36, 95% confidence interval: 0.16 to 0.81, p = 0.01). No significant differences in bleeding or infarct size were observed.

CONCLUSIONS

Immediate transfer for PCI did not improve the primary outcome significantly, but reduced the rate of death, reinfarction, or stroke at 12 months in patients with STEMI, treated with thrombolysis and clopidogrel in areas with long transfer distances. (Norwegian Study on District Treatment of ST-Elevation Myocardial Infarction; NCT00161005).

Myocardial perfusion in ST-elevation myocardial infarction treated successfully with primary angioplasty

OBJECTIVES

To study myocardial perfusion in ST-elevation myocardial infarction (STEMI) treated successfully with primary angioplasty. Additionally, to evaluate the predictive value of perfusion on subsequent infarct size.

DESIGN

Fifty patients with acute STEMI and restoration of normal epicardial flow after primary angioplasty were included in the study. TIMI myocardial perfusion (TMP) grades were determined at the end of the procedure. Contrast enhanced magnetic resonance imaging (MRI) including first-pass perfusion and delayed enhancement imaging were performed within five days and after three months.

RESULTS

The patients were divided into two groups: A=TMP 0-1, B=TMP 2-3. The early MRI showed significantly reduced myocardial perfusion in the infarct zone compared to remote myocardium in both groups (p<0.001), but the reduction was more pronounced in group A. The infarct sizes were smaller (p=0.0017) and the ejection fractions higher (p=0.0001) in group B than in group A at follow-up.

CONCLUSIONS

In STEMI, early impairments in myocardial perfusion were observed in spite of successful treatment with angioplasty. Marked early impairments in perfusion were associated with larger infarct sizes on MRI after three months.

Scintigraphic demonstration of myocardial perfusion and ischaemia associated with coronary artery bypass grafting

OBJECTIVES

To assess if myocardial perfusion scintigraphy (MPS) at rest can be of value in elucidating myocardial perfusion, ischaemia and perioperative myocardial infarction (PMI) associated with coronary artery bypass graft (CABG) surgery.

DESIGN

This was a prospective randomized study of patients undergoing elective CABG. Forty-eight patients in the control group underwent serial ECG recordings and measurements of CK-MB and cTnT. Fifty-four patients in the study group were additionally examined with MPS preoperatively and 2-4 days and 6 weeks postoperatively.

RESULTS

The study showed a highly significant (p < 0.001) improvement in myocardial radionuclide uptake from preoperatively to 2-4 days postoperatively. Judged from ECG and enzymatic changes, two control patients and one study patient only had PMI and no additional cases of PMI were demonstrated by MPS.

CONCLUSION

MPS at rest showed that CABG significantly improved myocardial perfusion, by demonstrating an increase in radionuclide uptake. In diagnosing PMI, we found that MPS provided no additional information beyond cardiac biochemical markers and ECG changes.

Validity of ejection fraction as a measure of myocardial functional state: impact of asynchrony

AIMS

The goal of this study was to test whether peculiarities of left ventricular (LV) regional function place limits on the validity of ejection fraction (EF) as a measure of the myocardial functional state.

METHODS AND RESULTS

Transthoracic and transoesophageal data from patients with a variety of cardiac conditions were used for analysis of LV regional function. The focus was on the effects of mechanical asynchrony. Ejection fraction was calculated on the basis of LV end-diastolic volume and end-systolic volume obtained by two different ways: (i) end-systolic volume as a whole; and (ii) the sum of all regional end-systolic volumes (which may occur at different times). The relative difference, D-EF, between EFs obtained by (i) and (ii) was taken as the 'merit' of EF. A value of zero is the highest merit. Irrespective of the examination method, we found that D-EF was always higher than zero, and that its value depended on the extent of mechanical asynchrony.

CONCLUSIONS

Ejection fraction is not the arithmetic average of regional EFs. An increase of asynchrony increases D-EF, i.e. it reduces the merit of EF as a measure of cardiac function.