Medicine (Western Health) - Research Publications
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ItemPretreatment with dual antiplatelet therapy in patients with ST-elevation myocardial infarction(WILEY, 2018-08-01)BACKGROUND: The optimal time to administer P2Y12 inhibitors in patients with ST-elevation myocardial infarction (STEMI) remains to be defined. We sought to assess whether a pretreatment strategy was associated with improved coronary reperfusion and clinical outcomes. METHODS: Consecutive patients from the Melbourne Interventional Group registry (2005-2014) who presented with STEMI and underwent primary PCI were included. Those who received any P2Y12 inhibitor prior to arrival in the cardiac catheterisation laboratory were included in the pretreatment group. The primary endpoints were the proportion of patients with initial TIMI flow grade <3 and in-hospital bleeding. The secondary endpoints were 12-month mortality and major adverse cardiovascular events (MACE). RESULTS: Of the 2,807 patients included, 892(31.8%) received pretreatment. Clopidogrel was the most common P2Y12 inhibitor used (79.6%). Pretreatment was associated with less thromboaspiration and GPIIb/IIIa inhibitor use (both P < 0.01). Pretreatment was not associated with lower rates of TIMI flow <3 on initial angiogram (78.0% vs. 80.7%, P = 0.18) nor with increased in-hospital bleeding (3.6% vs. 3.9%, P = 0.67). Pretreatment was associated with lower 12-month mortality (4.7% vs. 7.0%, P = 0.02) but similar MACE rate (13.0% vs. 14.1%, P = 0.43). Multivariate analysis revealed pretreatment was not an independent predictor of 12-month mortality (OR 0.79; 95% CI 0.5-1.3, P = 0.32). CONCLUSION: Pretreatment with a P2Y12 inhibitor in patients with STEMI was not routine practice in our Australian cohort and was not associated with improved coronary reperfusion or clinical outcomes. Larger studies are required to definitively ascertain the risk/benefit ratio of dual antiplatelet therapy pretreatment in STEMI.
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ItemClinical outcomes following ST-elevation myocardial infarction secondary to stent thrombosis treated by percutaneous coronary intervention(WILEY, 2020-10-01)OBJECTIVES: To assess the clinical outcomes of patients presenting with ST-elevation myocardial infarction (STEMI) secondary to stent thrombosis (ST) compared to those presenting with STEMI secondary to a de novo culprit lesion and treated by percutaneous coronary intervention (PCI). BACKGROUND: ST is an infrequent but serious complication of PCI with substantial associated morbidity and mortality, however with limited data. METHODS: We studied consecutive patients who underwent PCI for STEMI from 2005 to 2013 enrolled prospectively in the Melbourne Interventional Group registry. Patients were divided into two groups: the ST group comprised patients where the STEMI was due to ST and the de novo group formed the remainder of the STEMI cohort and all patients were treated by PCI. The primary endpoint was 30-day all-cause mortality. RESULTS: Compared to the de novo group (n = 3,835), the ST group (n = 128; 3.2% of STEMI) had higher rates of diabetes, hypertension and dyslipidemia, established cardiovascular diseases, myocardial infarction, and peripheral vascular disease, all p < .01. Within the ST group, very-late ST was the most common form of ST, followed by late and early ST (64, 19, and 17%, respectively). There was no significant difference in the primary outcome between the ST group and the de novo group (4.7 vs. 7.1%, p = .29). On multivariate analysis, ST was not an independent predictor of 30-day mortality (odds ratio: 0.62, 95% confidence interval: 0.07-1.09, p = .068). CONCLUSION: The short-term prognosis of patients with STEMI secondary to ST who were treated by PCI was comparable to that of patients with STEMI due to de novo lesions.
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ItemOutcomes of cardiogenic shock complicating acute coronary syndromes(WILEY, 2020-09-01)OBJECTIVES: We aimed to assess the outcomes of cardiogenic shock (CS) complicating acute coronary syndromes (ACS). BACKGROUND: CS remains the leading cause of mortality in patients presenting with ACS despite advances in care. METHODS: We studied 13,184 patients undergoing percutaneous coronary intervention (PCI) for all subtypes of ACS enrolled prospectively in a large multicentre Australian registry (Melbourne Interventional Group registry) from 2005 to 2013. All-cause mortality was obtained via linkage to the National Death Index. Patients were divided into those with and those without CS. RESULTS: Compared to the non-CS group (n = 12,548, 95.2%), the CS group (n = 636, 4.8%) had a higher proportion of out-of-hospital cardiac arrest (OHCA) (31.1 vs. 2.2%) and ST-elevation myocardial infarction (STEMI) presentation (89 vs. 34%), both p < .01. Patients in the CS group had higher rates of in-hospital (40.4 vs. 1.2%) and 30-day (41 vs. 1.7%) mortality compared to the non-CS group. Long-term mortality over a median follow-up of 4.2 years was higher in the CS group (50.6 vs. 13.8%), p < .001. Trends of in-hospital and 30-day mortality rates of CS complicating ACS were relatively stable from 2005 to 2013. Predictors of long-term NDI-linked mortality within the CS group include severe left ventricular systolic dysfunction (HR 3.0), glomerular filtration rate (GFR) <30 (HR 2.56), GFR 30-59 (HR 1.94), OHCA (HR 1.46), diabetes (HR 1.44), and age (HR 1.02), all p < .05. CONCLUSIONS: Rates of CS-related mortality complicating ACS have remained very high and steady over nearly a decade despite progress in STEMI systems of care, PCI techniques, and medical therapy.
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ItemAssociation of Body Mass Index and Extreme Obesity With Long-Term Outcomes Following Percutaneous Coronary Intervention(WILEY, 2019-11-05)Background Previous studies have reported a protective effect of obesity compared with normal body mass index (BMI) in patients undergoing percutaneous coronary intervention (PCI). However, it is unclear whether this effect extends to the extremely obese. In this large multicenter registry-based study, we sought to examine the relationship between BMI and long-term clinical outcomes following PCI, and in particular to evaluate the association between extreme obesity and long-term survival after PCI. Methods and Results This cohort study included 25 413 patients who underwent PCI between January 1, 2005 and June 30, 2017, who were prospectively enrolled in the Melbourne Interventional Group registry. Patients were stratified by World Health Organization-defined BMI categories. The primary end point was National Death Index-linked mortality. The median length of follow-up was 4.4 years (interquartile range 2.0-7.6 years). Of the study cohort, 24.8% had normal BMI (18.5-24.9 kg/m2), and 3.3% were extremely obese (BMI ≥40 kg/m2). Patients with greater degrees of obesity were younger and included a higher proportion of diabetics (P<0.001). After adjustment for age and comorbidities, a J-shaped association was observed between different BMI categories and adjusted hazard ratio (HR) for long-term mortality (normal BMI, HR 1.00 [ref]; overweight, HR 0.85, 95% CI 0.78-0.93, P<0.001; mild obesity, HR 0.85, 95% CI 0.76-0.94, P=0.002; moderate obesity, HR 0.95, 95% CI 0.80-1.12, P=0.54; extreme obesity HR 1.33, 95% CI 1.07-1.65, P=0.01). Conclusions An obesity paradox is still apparent in contemporary practice, with elevated BMI up to 35 kg/m2 associated with reduced long-term mortality after PCI. However, this protective effect appears not to extend to patients with extreme obesity.