Michael C Foster

Providence Hospital, Mobile, Alabama, United States

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Publications (4)31.43 Total impact

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    ABSTRACT: Previous angiographic studies have suggested that the future risk for major adverse cardiovascular events (MACEs) is related to coronary stenosis severity. The aim of this study was to use the grayscale and virtual histology (VH)-intravascular ultrasound (IVUS) data from the Providing Regional Observations to Study Predictors of Events in the Coronary Tree (PROSPECT) study to identify underlying lesion morphologic characteristics that might explain these findings. In PROSPECT, patients presenting with acute coronary syndromes in whom percutaneous coronary intervention was successful underwent 3-vessel grayscale and VH-IVUS and were followed for a median of 3.4 years for the incidence of MACEs. Overall, 3,115 nonculprit lesions detected by IVUS were divided into quartiles according to baseline angiographic diameter stenosis. From the first to fourth quartiles, there were increases in the prevalence of lesions with IVUS minimum luminal areas ≤ 4 mm(2), IVUS plaque burden ≥ 70%, and VH-IVUS thin-cap fibroatheroma (13.4%, 22.0%, 24.2%, and 30.3%, respectively, p <0.001), along with an increased frequency of plaque ruptures and greater necrotic core volumes. The incidence of lesions with plaque burden ≥ 70%, minimum luminal area ≤ 4 mm(2), and VH thin-cap fibroatheroma was highest in the fourth quartile (0%, 0.4%, 0.4%, and 2.8% in the first through fourth quartiles, respectively, p <0.001). Three-year MACE rates were also highest in the fourth quartile (0.3%, 0.7%, 1.3%, and 5.1%, respectively, p <0.001). In conclusion, increasing angiographic diameter stenosis was associated with an increased frequency of grayscale and VH-IVUS lesion morphologic features that have been associated with adverse events and that may, in part, explain why future MACEs were related to baseline lesion severity.
    No preview · Article · May 2012 · The American journal of cardiology
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    ABSTRACT: The aim of this study was to characterize and evaluate the clinical impact of untreated atherosclerotic disease after percutaneous coronary intervention (PCI) in patients with acute coronary syndromes (ACS). Residual atherosclerotic disease after successful PCI may predispose future major adverse cardiovascular events (MACE). Compared with intravascular ultrasound (IVUS), angiography underestimates the presence and severity of coronary artery disease. Following successful PCI of all clinically significant lesions in 697 patients with ACS, 3-vessel grayscale and radiofrequency IVUS was performed. Lesions were prospectively characterized, and patients were followed for a median of 3.4 years. A total of 3,229 untreated lesions (4.89 ± 1.98 lesions/patient) were identified by IVUS, with mean plaque burden (PB) of 49.6 ± 4.2%. By angiography these nonculprit lesions were mild, with mean diameter stenosis of 38.9 ± 15.3%. At least 1 lesion with a PB ≥70% (PB70 lesion) was found in 220 (33%) patients. By multivariable analysis, a history of prior PCI and angiographic 3-vessel disease were independent predictors of PB70 lesions. Patients with PB70 lesions had greater total percent plaque volume, normalized PB, fibroatheromas, thin-cap fibroatheromas, and normalized volumes of necrotic core and dense calcium. Patients with PB70 lesions had greater 3-year rates of MACE due to untreated nonculprit lesions (20.8% vs. 7.7%, p < 0.0001). Among imaged nonculprit lesions, the proportion of PB70 lesions causing MACE was significantly greater than non-PB70 lesions (8.7% vs. 1.0%, p < 0.0001). After successful PCI of all angiographically significant lesions, overall untreated atherosclerotic burden remains high, and PB70 lesions are frequently present in the proximal and mid-coronary tree. Patients with PB70 lesions have greater atherosclerosis throughout the coronary tree, have more thin-cap fibroatheromas, and are at increased risk for future cardiovascular events. (PROSPECT: An Imaging Study in Patients With Unstable Atherosclerotic Lesions; NCT00180466).
    Full-text · Article · Mar 2012 · JACC. Cardiovascular imaging
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    Preview · Article · Mar 2012 · Journal of the American College of Cardiology
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    ABSTRACT: Animal models show impairment of arterial healing after drug-eluting stents (DES) compared with bare-metal stents (BMS). Virtual histology intravascular ultrasound (VH-IVUS) offers an opportunity to assess lesion morphology in vivo. We used VH-IVUS in 80 patients to assess long-term (median = 10 months) native artery vascular responses after 76 implantations of DES compared with 32 BMS. The presence of "necrotic core abutting the lumen" was evaluated at baseline and follow-up. At baseline, necrotic core abutting the lumen through the stent struts was observed in 76% of DES and 75% of BMS. Although the percentage of necrotic core within the plaque behind the stents did not change during follow-up in DES (23% [18%, 28%] to 22% [17%, 27%], P = .57) or BMS (22% [19%, 27%] to 20% [12%, 26%], P = .29), necrotic core abutting the lumen through the stent struts decreased more in BMS (75% to 19%, P < .001) than DES (76% to 61%, P = .036) because of the lack of an overlying, protective neointima in DES-treated lesions. Furthermore, within the adjacent reference segments, the incidence of necrotic core abutting the lumen decreased in BMS-treated lesions (proximal 23% to 0%, P = .023; distal 21% to 0%, P = .023), but not in DES (proximal 22% to 17%, P = .48; distal 23% to 21%, P = .82). Serial VH-IVUS analysis of DES-treated lesions showed a greater frequency of unstable lesion morphometry at follow-up compared with BMS. The apparent mechanism was a suppression of the protective neointimal hyperplasia layer coupled with a lack of vulnerable plaque resolution at reference segments in DES compared with BMS.
    No preview · Article · Feb 2010 · American heart journal