Influence of infarct-zone viability detected by rest Tc-99m sestamibi gated SPECT on left ventricular remodeling after acute myocardial infarction treated by percutaneous transluminal coronary angioplasty in the acute phase

Effect of changes in perfusion defect size during serial stress myocardial perfusion imaging on cardiovascular outcomes in patients treated with primary percutaneous coronary intervention after myocardial infarction

BACKGROUND

We evaluated the prognostic value of changes in perfusion defect size (PDS) on serial MPS in patients treated with primary percutaneous coronary intervention (PCI) after acute myocardial infarction (AMI).

METHODS

We enrolled 112 patients treated with primary PCI after AMI who underwent two stress MPS within 1 month and after 6 months. Improvement in PDS was defined as a reduction ≥5%. Remodeling was defined as an increase in left ventricular (LV) end-diastolic volume index ≥20%. Cardiac events included cardiac death, nonfatal MI, unstable angina, repeated revascularization, and heart failure.

RESULTS

During a median follow-up of 86 months, 22 events occurred. Event rate was higher (P < .01) in patients with worsening of PDS compared to those with unchanged or improved PDS. Moreover, patients with remodeling had a higher (P < .001) event rate compared to those without. At Cox analysis, worsening of PDS and remodeling resulted independent predictors of events (both P < .01). Patients with both worsening of PDS and remodeling had the worst event-free survival (P <.001).

CONCLUSION

In patients treated with primary PCI after AMI, worsening of PDS and remodeling are associated to higher risk of events at long-term follow-up. Gated stress MPS improves risk stratification in these patients.

Predictors of ventricular remodelling in patients with reperfused acute myocardial infarction and left ventricular dysfunction candidates for bone marrow cell therapy: insights from the BONAMI trial

PURPOSE

Few data are available regarding the relation of left ventricular (LV) mechanical dyssynchrony to remodelling after acute myocardial infarction (MI) and stem cell therapy. We evaluated the 1-year time course of both LV mechanical dyssynchrony and remodelling in patients enrolled in the BONAMI trial, a randomized, multicenter controlled trial assessing cell therapy in patients with reperfused MI.

METHODS

Patients with acute MI and ejection fraction (EF) ≤ 45 % were randomized to cell therapy or to control and underwent thallium single-photon emission computed tomography (SPECT), radionuclide angiography, and echocardiography at baseline, 3 months, and 1 year. Eighty-three patients with a comprehensive 1-year follow-up were included. LV dyssynchrony was assessed by the standard deviation (SD) of the LV phase histogram using radionuclide angiography. Remodelling was defined as a 20 % increase in LV end-systolic volume index (LVESVI) at 1 year.

RESULTS

At baseline, LVEF, wall motion score index, and perfusion defect size were significantly impaired in the 43 patients (52 %) with LV remodelling (all p < 0.001), without significant increase in LV mechanical dyssynchrony. During follow-up, there was a progressive increase in LV SD (p = 0.01). Baseline independent predictors of LV remodelling were perfusion SPECT defect size (p = 0.001), LVEF (p = 0.01) and a history of hypertension (p = 0.043). Bone marrow cell therapy did not affect the time-course of LV remodelling and dyssynchrony.

CONCLUSIONS

LV remodelling 1 year after reperfused MI is associated with progressive LV dyssynchrony and is related to baseline infarct size and ejection fraction, without impact of cell therapy on this process.

Low-dose dobutamine adds incremental value to late gadolinium enhancement cardiac magnetic resonance in the prediction of adverse remodelling following acute myocardial infarction

AIMS

To examine the relative and combined value of late gadolinium enhancement (LGE) and low-dose dobutamine (LDD) cardiac magnetic resonance (CMR) to predict 'adverse remodelling' (AR) following acute myocardial infarction (AMI).

METHODS AND RESULTS

Forty-five patients with AMI were recruited. CMR was performed 2-4 days after presentation and at 6 months. Ventricular wall motion and volume were recorded at rest and following dobutamine infusion. Measures of first pass perfusion, persistent microvascular obstruction (PMO), and LGE were obtained following contrast administration. Quantitation was performed using the MEDIS 6.2 software. Regression analysis was employed to determine the univariables and multivariate models most predictive of AR at 6 months. The incremental and relative value of LDD over LGE was investigated. The most predictive univariable was 'volume of PMO' (r = 0.51, r2 = 0.26, P < 0.001). The optimal 'combined' multivariate model, utilizing data from all components, was highly predictive of AR (r = 0.82, r2 = 0.67, P < 0.001). The optimal model using parameters only from the LGE component also predicted remodelling (r = 0.65, r2 = 42.0, P = 0.001) but with less accuracy. In contrast, the optimal model using variables from the LDD component alone predicted remodelling with a similar accuracy to the optimal combined model (r = 0.82, r2 = 0.67, P < 0.001).

CONCLUSION

A comprehensive CMR examination accurately predicts AR following AMI. LDD is superior to LGE CMR in this respect. These data suggest that LDD not only adds incremental value to LGE in the prediction of remodelling post-AMI but also may be utilized alone with the same predictive power.

Rest and low-dose dobutamine Tc-99m-mibi gated-SPECT for early prediction of left ventricular remodeling after a first reperfused myocardial infarction

BACKGROUND

Left ventricular (LV) remodeling after myocardial infarction (MI) occurs frequently despite successful percutaneaous coronary intervention (PCI) but cannot be predicted by simple clinical parameters.

METHODS AND RESULTS

This prospective study tested the value of rest and low-dose dobutamine (LDD) Tc-99m-mibi gated-SPECT for early prediction of LV remodeling in patients treated by PCI in the acute phase of a first MI. Infarct size, infarct severity, regional wall motion abnormality (RWMA), and wall thickening score (WTs) were assessed at rest and on LDD by SPECT 6 +/- 2 days after MI in 40 patients. LV remodeling was defined as 20% increase at 6 months in LV end-diastolic volume assessed by MRI. Infarct severity at rest showed the best predictive values for left remodeling (PPV: 86%, NPV: 88%, accuracy: 88%; AUC: 0.750). Functional parameters at neither rest nor LDD study further improved predictive values of the SPECT imaging.

CONCLUSIONS

Infarct severity assessed by Tc-99m-sestamibi gated-SPECT performed in the subacute phase of a first STEMI predicts LV remodeling with high accuracy without incremental value nor of functional parameters nor of LDD. Therefore, our results suggest that LDD should not be used in this setting.

Assessment of left ventricular volumes and function by cine-MR imaging depending on the investigator's experience

AIMS

To analyze the reproducibility of LV volumes calculated by cardiac magnetic resonance imaging (CMRI) and to compare them to those obtained by conventional ventriculography.

METHODS

A total of 30 patients with stable ischemic heart disease were prospectively included. Each underwent CMRI twice and ventriculography. Left ventricular end diastolic volume (EDV), end systolic volume (ESV) and LV ejection fraction (EF) were calculated by two radiologists at different level of experience. Intraobserver, interobserver and interstudy variabilities were assessed.

RESULTS

The cut off values were: intraobserver variability (EDV, ESV, EF): 9.4 ml, 5.3 ml, 3.3% for well-trained radiologist; 13.1 ml, 7.5 ml, 4.1% for less-trained radiologist. interobserver variability: EDV: 11.7 and 10.4 ml; ESV: 7.0 and 6.6 ml; EF: 3.9 and 4.2%. interstudy variability (EDV, ESV, EF): 11.6 and 12.6 ml, 7.1 and 7.4 ml, 3.9 and 3.5%, for experienced and less-trained observers. Statistical differences were found between CMRI and ventriculography: CMRI underestimation of EDV and EF, overestimation of ESV.

CONCLUSIONS

CMRI volumetric quantification of LV volumes and function is highly reproducible at different levels of experience, but not interchangeable with those obtained by ventriculography.