Original ArticlePrognostic value of divergent pattern detection by 99mTc-sestamibi gated SPECT in patients with anterior acute myocardial infarction
Introduction
Apical remodeling may be identified in myocardial perfusion-gated single-photon emission computed tomography (SPECT) by the presence of a divergent pattern (DP) of the left ventricle (LV), defined by a greater LV diameter at apical than at basal level.1 In patients with LV dysfunction of ischemic etiology, the DP has been identified in a sizable proportion of cases, all with history of prior acute myocardial infarction (AMI), and its presence has been shown to be an adverse prognostic indicator.1 So far, there are no data about the DP incidence in patients with recent AMI, and it is unclear whether this pattern could have some prognostic usefulness for predicting the subsequent evolution of these patients. This could be of some interest, because even among those timely and successfully treated with primary percutaneous coronary interventions (PCI) there is a proportion of cases with massive myocardial damage and subsequent unfavorable evolution, including LV remodeling.2,3 Gated SPECT performed in AMI patients allows assessing simultaneously the infarct size and infarct severity and measuring the LV end-diastolic (EDV) and end-systolic (ESV) volumes, and the LV ejection fraction (LVEF).4, 5, 6 We found it interesting to explore the incidence of DP in this patient population and its relationship with short-term outcome.
Section snippets
Patient Population and Study Protocol
The patient population included 150 patients with anterior ST-elevation myocardial infarction (STEMI), all successfully treated early after symptom onset with primary PCI and stenting of the infarct-related vessel. The patients had been enrolled in two protocols aimed at examining the infarct size after a recent AMI treated by primary PCI.7,8 In both protocols, the diagnosis of AMI required the presence of typical chest pain lasting more than 30 minutes and < 12 hours together with > 0.1 mV ST
Results
DP was detected in 26/150 patients (17%) (Fig. 1). Table 1 summarizes the main features of the patient population, divided according to the presence or absence of DP. Patients with DP had larger infarct size (28.1 ± 19% vs. 15.6 ± 16.8%, P < 0.01), worse infarct severity (0.31 ± 0.13 vs. 0.43 ± 0.17, P < 0.01), larger ESV (90 ± 32 vs. 67 ± 36 mL, P < 0.03), a significantly lower EF (32.6 ± 9% vs. 41.4 ± 10.4%, P < 0.001) and a (not significantly) larger EDV (132 ± 39 vs. 110 ± 42 mL, NS) than
Discussion
Patients with large transmural AMI, especially of the antero-lateral wall, may undergo a remodeling process with infarct area dilatation and subsequent development of LV aneurysms.16 Factors associated with remodeling include infarct size, anterior location, delayed treatment, and unsuccessful reperfusion, which can occur because of epicardial and microvascular problems. The remodeling process results in combined systolic and diastolic dysfunction with a progressive increase in ESV and EDV in
New Knowledge Gained
Gated SPECT is a diagnostic, non-invasive, validated investigation in the field of myocardial perfusion imaging. Patients with large transmural AMI may undergo a remodeling process with infarct area dilatation and subsequent development of LV aneurysms, leading to a combined systolic and diastolic dysfunction.
Gated SPECT could be used to estimate DP and to identify patients with large transmural AMI at high risk of remodeling.
Conclusion
This study demonstrates that DP is not infrequent early after AMI successfully treated by primary PCI. The detection of DP early after AMI can be useful to predict the occurrence of LV remodeling in the short-term follow-up and has more general unfavorable prognostic implications.
Disclosures
Raffaella Calabretta, MD; Angelo Castello, MD; Cristina Giglioli, MD; Emanuele Cecchi, MD; Giampaolo Cerisano, MD; Marcus Hacker, MD; Roberto Sciagrà, MD: Disclosures: none.
Funding
Raffaella Calabretta, MD; Angelo Castello, MD; Cristina Giglioli, MD; Emanuele Cecchi, MD; Giampaolo Cerisano, MD; Marcus Hacker, MD; Roberto Sciagrà, MD: Not applicable.
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