The extent of regional wall motion abnormalities identifies patients at risk of extensive left ventricular remodeling: implications for the design of post myocardial infarction trials.
Author(s): Zanolla L, Marino P, Golia G, Anselmi M, Zardini P, Borghi C, Ambrosioni E
Affiliation(s): Cattedra e Divisione Clinicizzata di Cardiologia, Universita di Verona.
Publication date & source: 1999-01, G Ital Cardiol., 29(1):20-6.
Publication type: Clinical Trial; Comparative Study ; Controlled Clinical Trial; Multicenter Study; Randomized Controlled Trial
BACKGROUND: The FAMIS (Fosinopril in Acute Myocardial Infarction Study) was a multicenter, placebo-controlled, double-blind trial designed to evaluate the safety and the efficacy of fosinopril in reducing left ventricular enlargement after acute anterior myocardial infarction. We evaluated the echocardiographic examinations performed during the trial in order to assess the trend of the remodeling process over time and to evaluate the role of infarct size in identifying patients at risk of progressive left ventricular dilation. METHODS: A complete echocardiographic examination was performed on admission, before discharge and three months later. Patients undergoing coronary bypass surgery or PTCA had a further examination prior to the procedure. The echocardiograms were analyzed at a central laboratory, and the end-diastolic and end-systolic left ventricular volumes were computed by using a modified Simpson's rule technique. Regional wall motion was evaluated using the centerline method, analyzing the left ventricular boundary along 100 chords perpendicular to the centerline constructed midway between the end-diastolic and the end-systolic contours. A quantitative infarct-size index was then computed according to the number of chords with a fractional shortening equal to or less than 5%. RESULTS: Left ventricular end-diastolic and end-systolic volume index significantly increased over time (p < 0.0001); as a result, the stroke volume increased (p < 0.0001) but the ejection fraction did not change. Patients were then divided according to the three-month infarct-size index. For both end-diastolic and end-systolic volume, not only did larger infarcts had higher volumes, but there was also a greater increase from baseline to 3 months. Moreover, larger infarcts had a lower ejection fraction, with a further reduction over the three months, while smaller infarcts had higher values and an increase over time. An infarct-size index of 25 or larger allowed prospective identification at the baseline examination of patients at risk of subsequent left ventricular dilation. CONCLUSIONS: In conclusion, patients at greatest risk of left ventricular dilation, namely those with larger infarct size, constitute a group that is worth considering for any therapeutic effort for reducing the remodeling process. These patients could in fact benefit from therapeutic strategies aimed at the reduction of left ventricular remodeling and should be studied in clinical trials.