Min Zhang

Duke University, Durham, North Carolina, United States

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Publications (3)34.87 Total impact

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    ABSTRACT: To determine whether predictors of sudden cardiac death (SCD) vary with time after myocardial infarction (MI). We analysed 11 256 patients enrolled in VALIANT. Landmark analysis and Cox proportional hazards modelling were used to predict SCD during hospitalization, from discharge to 30 days, 30 days to 6 months, and 6 months to 3 years. The cumulative incidence of SCD was 8.6% (n = 965). Initially, higher baseline heart rate [HR 1.20 per 10 b.p.m. (95% CI 1.06-1.37)] and impaired baseline creatinine clearance [HR 0.82 per 10 mL/min (95% CI 0.74-0.91)] were stronger predictors of SCD. With long-term follow-up, prior MI [HR 1.71 (95% CI 1.39-2.10)], initial left ventricular ejection fraction <40% [HR 0.67 per 10% (95% CI 0.58-0.78)], and recurrent cardiovascular events [HR 1.47 for rehospitalization (95% CI 1.17-1.86)] were more robust risk stratifiers for SCD. Atrial fibrillation post-MI was associated with an increased risk of SCD over the entire follow-up period. As time passed, the associations between baseline clinical characteristics and SCD decreased and time-updated assessments became more important. Predictors of SCD change with time after MI. Future studies of risk stratification for SCD should account for changes in these factors with time after MI.
    No preview · Article · Oct 2009 · European Heart Journal
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    ABSTRACT: Because acute occlusion of coronary arteries supplying the inferolateral myocardium frequently eludes standard 12-lead electrocardiogram (ECG) diagnosis, these patients may present as non-ST-segment elevation acute coronary syndromes (NSTE-ACS). We examined culprit artery occlusion among 1,957 NSTE-ACS patients in the Platelet IIb/IIIa Antagonism for the Reduction of Acute Coronary Syndrome Events in a Global Organization Network trial who underwent diagnostic coronary angiography. We compared baseline characteristics, electrocardiographic findings, in-hospital treatment, and long-term outcomes between patients with and without occluded culprit arteries. The culprit artery was occluded in 528 (27%) patients. Culprit lesions were more frequently identified in the inferolateral territory among patients with an occluded culprit artery (63%) compared with those with a nonoccluded artery (45%, P < .0001). Patients with an occluded culprit artery were younger, more often male, and more likely to have had a prior myocardial infarction. Despite similar in-hospital treatment, patients with an occluded culprit artery had larger infarcts (median peak creatine kinase-MB 4.3 vs 2.1 x upper limit of normal, P < .0001) and higher risk-adjusted 6-month mortality (hazard ratio 1.72, 95% CI 1.07-2.79). More than 25% of NSTE-ACS patients had an occluded culprit artery on angiography. These patients may represent ST-segment elevation myocardial infarction equivalents; thus, improved early risk stratification techniques would help more rapidly triage these high-risk patients to an early invasive management strategy.
    No preview · Article · May 2009 · American heart journal
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    ABSTRACT: Non-invasive risk stratification of low- and intermediate-risk non-ST-elevation acute coronary syndromes (NSTE ACS) patients has been recommended, but limited data exist about the variation in clinical practice of stress testing in these patients and the impact of such testing on their outcomes. Patients with NSTE ACS enrolled in the GUSTO IIb (Global Use of Strategies To Open occluded coronary arteries in acute coronary syndromes-IIb) trial (n = 8011) were analysed to evaluate patterns of stress testing in US and non-US patients and to further evaluate the clinical characteristics, procedure use, and outcomes of patients who underwent stress testing compared with those who did not. Stress testing was performed in 1878 (24%) patients. Compared with patients not undergoing stress testing, those undergoing stress testing had low-risk characteristics and significantly lower death (0.6% vs. 4.8%), and death or myocardial infarction (MI, 3.9% vs. 11%) rates at 30 days. Stress testing was performed as often after as before coronary angiography. Importantly, stress testing was helpful in stratifying patients into low (equivocal or negative test) or high (positive test) risk groups (30 day death 3.1% vs. 5%). Stress testing was performed more often in non-US than US patients, and US patients were 3.5 times more likely to undergo imaging as part of stress testing. However, the risks of 30-day death or MI; 6-month death, MI or revascularization; and 1-year death did not differ between US and non-US patients. Stress testing is commonly performed in low-risk NSTE ACS patients and provides modest additional prognostic information in this cohort. Significant geographical variation exists in the use of stress testing. Therefore, in the current practice environment where cardiac catheterization is often the first diagnostic modality used in patients with NSTE ACS, the role of non-invasive testing both before and after invasive procedure is in need of further study.
    Full-text · Article · May 2008 · European Heart Journal