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.

[Postinfarction management]

Postinfarction management of patients must be individualized. The essential prognostic factor is the ejection fraction, measured at one month. The four basic drugs to be used in combination are antithrombotics, beta-blockers, converting enzyme inhibitors and statins. The objective of treatment is to reach the dose regimens used in clinical trials. Cardiovascular rehabilitation and treatment education must be proposed widely to improve control of risk factors, explain the role of each drug prescribed and teach the appropriate use of nitroglycerin and of emergency medical services. Indications for myocardial revascularization depend on the coronary anatomy. Indications for an implantable defibrillator and for cardiac replacement depend on the ejection fraction and on the existence of heart failure uncontrolled by drug treatment.