Artificial intelligence in cardiovascular imaging: state of the art and implications for the imaging cardiologist.

Healthcare, conceivably more than any other area of human endeavour, has the greatest potential to be affected by artificial intelligence (AI). This potential has been shown by several reports that demonstrate equal or superhuman performance in medical tasks that aim to improve efficiency, diagnosis and prognosis. This review focuses on the state of the art of AI applications in cardiovascular imaging. It provides an overview of the current applications and studies performed, including the potential value, implications, limitations and future directions of AI in cardiovascular imaging.It is envisioned that AI will dramatically change the way doctors practise medicine. In the short term, it will assist physicians with easy tasks, such as automating measurements, making predictions based on big data, and putting clinical findings into an evidence-based context. In the long term, AI will not only assist doctors, it has the potential to significantly improve access to health and well-being data for patients and their caretakers. This empowers patients. From a physician's perspective, reliable AI assistance will be available to support clinical decision-making. Although cardiovascular studies implementing AI are increasing in number, the applications have only just started to penetrate contemporary clinical care.

Subspecialisation in cardiology care and outcome: should clinical services be redesigned, again?

BACKGROUND: Inpatient management of cardiac patients by cardiologists results in reduced mortality and hospitalisation. With increasing subspecialisation of the field because of growing management complexity and use of technological innovations, the impact of sub-specialisation on patient outcomes is unclear. AIM: To investigate whether management by subspecialty cardiologists impacts the outcomes of patients with subspecialty-specific diseases. METHODS: All patients admitted to a tertiary centre over nine years with a diagnosis of heart failure, acute coronary syndrome (ACS) or primary arrhythmia were reviewed. The outcomes of these patients managed by cardiologists subspecialised in their admission diagnosis (heart failure specialists, interventionalists and electrophysiologists) were compared with those treated by general cardiologists. RESULTS: Heart failure was diagnosed in 1704 patients, ACS in 7763 and arrhythmia in 4398. There was no difference in length of stay (LOS) (P = 0.26), mortality (P = 0.57) or cardiovascular readmissions (P = 0.50) in heart failure patients treated by general cardiologists compared with subspecialists. In ACS patients, subspecialty management was associated with reduced LOS, cardiovascular readmissions and mortality (all P < 0.05). This reduction in mortality was seen mainly in lower risk patients (P < 0.05). There was a reduction in LOS and cardiovascular readmissions in arrhythmia patients receiving subspecialty management (both P < 0.05) but no difference in mortality (P = 0.14). ACS patients managed by interventionalists were more likely to undergo coronary intervention (P < 0.05). Electrophysiologists more frequently referred patients for catheter ablation and pacemaker implantation than general cardiologists (P < 0.05). CONCLUSIONS: The benefits of subspecialty care seem attributable to the appropriate selection of patients who would benefit from technological innovations in care. These results suggest that the development of healthcare systems which align cardiovascular disease with the subspecialist may be more effective.

Impact of age, gender and indigenous status on access to diagnostic coronary angiography for patients presenting with non-ST segment elevation acute coronary syndromes in Australia.

Using Australian guidelines for management of acute coronary syndromes, we investigated the proportion of high-risk patients enrolled in the Acute Coronary Syndromes Prospective Audit registry who received a coronary angiogram. A prospective nationwide multicentre registry involving 39 Australian hospitals was used. The study cohort were patients with high-risk clinical features without ST segment elevation (n = 1948) admitted from emergency departments between 1 November 2005 and 31 July 2007. Eighty nine per cent of patients with ST segment elevation myocardial infarction and only 53% of eligible patients with high-risk acute coronary syndromes with no ST elevation received a diagnostic angiogram. Increasing age was associated with lower rates of angiography; a high-risk patient at the age of ≥ 70 years was 19% less likely to receive an angiogram than one at the age of <70 years (risk ratio (RR) = 0.81 95% confidence interval (CI) 0.76, 0.76). Women were 26% less likely than men to receive an angiogram (RR = 0.74; 95% CI = 0.65, 0.83). The adjusted RR from the multivariate analysis suggests that a patient at the age of ≥ 70 years was 35% less likely to receive an angiogram than one at the age of <70 years (RR = 0.65, 95% CI = 0.60, 0.73), and that women were 13% less likely than men to receive an angiogram (RR = 0.87, 95% CI = 0.80, 0.96). Indigenous patients were as likely to access angiography as eligible non-indigenous patients (RR = 1.03, 95% CI 0.85, 1.25). There is underinvestigation of high-risk patients without ST segment elevation in Australian hospitals, particularly for women and older patients. Indigenous patients are younger and have poorer risk profiles, and represent a group that would benefit from greater investment in prevention strategies.

Patterns of inflammatory activation associated with precipitants of acute coronary syndromes: a case-crossover study.

AIMS: We sought to assess a broad array of possible precipitants of acute coronary syndromes (ACS) and evaluate their association with detectable inflammatory activation. METHODS AND RESULTS: Within a case-crossover design, using a standardised questionnaire, interviews among 348 ST-elevation myocardial infarction (44%) or high-risk non-ST-elevation ACS patients (56%), explored potential precipitants, including: infection (INF)-temperature >38°C and/or respiratory tract, urinary or skin infection; inflammation (INFL)-exacerbation of inflammatory conditions; exercise (EX)-moderate to heavy exercise; fast food (FF)-consumption of a meal purchased from a fast food company. Risk and control periods were: weekly over 8 weeks for INF and INFL; 24 hourly over 4 days for FF and 4 hourly over 48 h for EX. C-reactive protein (CRP) levels were assessed at admission. These precipitants were identified in 203/348 (58.3%) patients. An increased temporal risk was observed for: INF (0-7 days vs 7-8 weeks odds ratio (OR): 7.5, confidence interval (CI): 1.7-67.6, P = 0.002); INFL (0-7 days vs 7-8 weeks OR: 14.0, CI: 2.13-591.9, P = 0.001); EX (0-4 h vs 24-28 h OR: 2.2, CI: 1.3-3.5, P = 0.001) and FF (0-24 h vs 72-96 h OR: 5.67, CI: 1.6-30.2, P = 0.003). CRP levels were significantly elevated among patients reporting infective and inflammatory potential precipitants, but not among those reporting fast food consumption and unaccustomed moderate-heavy exercise. CONCLUSION: Infection, inflammatory conditions, moderate-heavy exercise and potentially fast food consumption appear to precipitate high-risk ACS. Increased inflammation as measured by CRP was not consistently detected despite the identification of an ACS precipitant. Strategies that target improved overall health may also lead to fewer ACS events through a reduction in triggers.

Outcome trial data on sodium glucose cotransporter-2 inhibitors: Putting clinical benefits and risks in perspective.

BACKGROUND: Sodium glucose cotransporter-2 (SGLT2) inhibitors have significant heart failure and renoprotective benefits with a wide spectrum of unfamiliar and potentially serious adverse effects. Limited understanding of the risk-benefit profile of SGLT2 inhibitor treatment may result in under utilisation by prescribers and patients. METHODS: Data from recent seminal randomized, placebo-controlled, outcome trials for multiple SGLT2 inhibitors were incorporated. Trial populations were sub-classified into high cardiovascular risk T2DM, HFrEF, and CKD. Efficacy outcomes of heart failure hospitalisation (HFH), cardiovascular (CV) mortality, total mortality, and prevention of renal deterioration were examined. Safety outcomes included were major hypoglycaemia, diabetic ketoacidosis (DKA), urinary tract infections (UTI), mycotic genital infections (MGI), hypotension, amputations and fractures. Absolute risk reduction/increase were used to calculate number needed to treat/harm. RESULTS: Trial data comprised 71,545 patients, of which 53,144 were high risk T2DM, 9696 HFrEF and 8705 CKD. For HFrEF, NNT for HFH was 18, CV mortality 93, total mortality 76, prevention of renal deterioration 143 and prevention of DKA 6224. NNH for UTI was 557, MGI 356, hypotension 120, hypoglycaemia 574, amputations 707 and fractures 858. For CKD, NNT for HFH was 116, CV mortality 245, total mortality 138, and prevention of renal deterioration was 63. NNH for DKA was 1458, UTI 309, MGI 291, hypotension 165, hypoglycaemia 374, amputations 4450 and fractures 696. In the T2DM cohort, NNT for HFH was 139, CV mortality 851, total mortality 601 and prevention of renal deterioration 558. NNH DKA was 1525, UTI 239, MGI 69, hypotension 325, hypoglycaemia 472, amputations 1578 and fractures 9569. CONCLUSIONS AND RELEVANCE: The cardiovascular and renal protective benefits of SGLT2 inhibitors far outweigh the risks. This paper puts into perspective the benefits and risks of treatment with SGLT2 inhibitors for clinicians and patients.

An invasive management strategy is associated with improved outcomes in high-risk acute coronary syndromes in patients with chronic kidney disease.

INTRODUCTION: Chronic kidney disease (CKD) is associated with poor outcomes after acute coronary syndromes, yet selection for invasive investigation and management is low. METHODS: Patients presenting with ST segment elevation myocardial infarction (STEMI) or intermediate- to high-risk non-ST segment elevation acute coronary syndrome (NSTEACS) (n=2597) were stratified into groups based on kidney function, defined as normal (glomerular filtration rate (GFR)≥60mL/min/1.73m(2) ), moderate CKD (GFR 30-59mL/min/1.73m(2) ) and severe CKD (GFR <30mL/min/1.73m(2)). Based on these stratums of kidney function, incidence and outcome measures were obtained for: rates of angiography and revascularization; 6-month mortality; and the incidence and outcome of in-hospital acute kidney impairment (AKI). RESULTS: Patients with CKD were less likely to be offered coronary angiography after STEMI/NSTEACS (P<0.001); however, after selection, revascularization rates were similar (percutaneous coronary intervention (P=0.8); surgery (P=0.4)). Six-month mortality rates increased with CKD (GFR≥60, 2.8%; GFR 30-59, 9.9%; GFR<30, 16.5%, P≤0.001), as well as the combined efficacy/safety end-point (GFR≥60, 9.4%; GFR 30-59, 20.2%; GFR<30, 27.1%, P≤0.001). Six-month mortality was lower in patients who had received prior angiography (GFR≥60, 1.5% vs 3.6%, P=0.001; GFR 30-59, 5.1% vs 12.7%, P<0.001; GFR<30, 7.3% vs 18.5%, P=0.094). Risk of AKI increased with CKD (GFR≥60, 0.7%; GFR 30-59, 3.4%; GFR<30, 6.8%, P≤0.001), and was associated with high 6-month mortality (35.6% vs 4.1%, P<0.001). CONCLUSIONS: In patients with CKD after STEMI/NSTEACS, 6-month mortality and morbidity is high, selection for angiography is lower, yet angiography is associated with a reduced long-term mortality, and with comparable revascularization rates to those without CKD. In-hospital AKI is more common in CKD and predicts a high 6-month mortality.

Clinical effectiveness in everyday practice: improving outcomes for all patients through a national acute coronary syndrome data collaborative.

The management of acute coronary syndromes (ACS) has an extensive and impressive evidence-base with which to guide clinical practice. Despite this, translation to the clinical environment has proved to be challenging and incomplete and can be attributed to patient, provider and system factors. Causes of suboptimal guideline adherence relate to diverse issues, including patient complexity, barriers in knowledge translation of guideline recommendations and a limited capacity within health services. Addressing these factors may enable more effective guideline implementation. In Australia, the infrastructure for clinical data management is fragmented, uncoordinated and often administratively driven, compromising access to important information, which might improve clinical effectiveness. An integrated approach is required to improve clinical effectiveness in ACS care in Australia. Greater access to information both to assist in clinical decision-making and monitoring outcomes may help direct the focus towards understudied populations and improve performance and clinically relevant outcomes. A peer-led initiative based on common datasets, providing rapid feedback, while developing and disseminating a 'toolbox' of proven and sustainable interventions, could improve clinical effectiveness in the Australian management of ACS and provides a rationale for a national ACS registry.

Unperceived treatment gaps in acute coronary syndromes.

BACKGROUND: Despite a strong evidence-base for several therapies recommended in the management of acute coronary syndromes (ACS), many patients do not receive these therapies. The barriers preventing translation of evidence into practice are incompletely understood. The aim of this study was to survey clinicians regarding barriers to implementing recommendations of recently published national clinical guidelines and to determine the extent to which these impact clinical practice. METHODS: A survey of clinicians at hospitals included in Australian Collaborative Acute Coronary Syndromes Prospective Audit (ACACIA, n = 3402, PML0051) was conducted, measuring self-stated knowledge, beliefs and guideline-concordant behaviours in relation to their care of ACS patients. Correlations between individual respondents' self-estimated rates and clinician's institutional rates of guideline-concordant behaviours were performed. RESULTS: Most respondents (n = 50/86, 58%) were aware of current guidelines and their scope, achieving 7/10 (Interquartile Range (IQR) = 2) median score on knowledge questions. Belief in benefits and agreement with guideline-recommended therapy was high. However, none of these factors correlated with increased use of guideline therapies. Apart from clopidogrel (r(s) = 0.28, p < 0.01) and early interventional therapy for high-risk non-ST elevation myocardial infarction (r(s) = 0.31, p < 0.01), there were no significant correlations between individual clinicians' self-estimated rates of guideline-concordant practice and rates recorded in ACACIA data for their respective institution. CONCLUSION: Beliefs about practice do not match actual practice. False beliefs regarding levels of evidence-based practice may contribute to inadequate implementation of evidence-based guidelines. Strategies such as continuous real-time audit and feedback of information for the delivery of care may help clinicians understand their levels of practice better and improve care.

Improving the management of acute coronary syndromes in Australia: translating evidence to outcomes.

Cardiovascular disease imposes a heavy burden of morbidity and mortality on the Australian community. This situation is likely to exacerbate as the number of elderly Australians increase. Management of acute coronary syndromes (ACS) is underpinned by a robust evidence base, which is outlined in clinical practice guidelines. Yet, despite wide diffusion of guidelines, many Australians who experience acute coronary syndromes do not receive optimal care. This article reviews what we have learnt from previous quality improvement initiatives and discusses what we need to know to improve acute coronary syndromes management in Australia.

Current management of acute coronary syndromes in Australia: observations from the acute coronary syndromes prospective audit.

BACKGROUND: Acute coronary syndromes (ACS) management is now well informed by guidelines extrapolated from clinical trials. However, most of these data have been acquired outside the local context. We sought to describe the current patterns of ACS care in Australia. METHODS: The Acute Coronary Syndrome Prospective Audit study is a prospective multi-centre registry of ST-segment elevation myocardial infarction (STEMI), high-risk non-ST-segment elevation ACS (NSTEACS-HR) and intermediate-risk non-ST-segment elevation ACS (NSTEACS-IR) patients, involving 39 metropolitan, regional and rural sites. Data included hospital characteristics, geographic and demographic factors, risk stratification, in-hospital management including invasive services, and clinical outcomes. RESULTS: A cohort of 3402 patients was enrolled; the median age was 65.5 years. Female and non-metropolitan patients comprised 35.5% and 23.9% of the population, respectively. At enrolment, 756 (22.2%) were STEMI patients, 1948 (57.3%) were high-risk NSTEACS patients and 698 (20.5%) were intermediate-risk NSTEACS patients. Evidence-based therapies and invasive management use were highest among suspected STEMI patients compared with other strata (angiography: STEMI 89%, NSTEACS-HR 54%, NSTEACS-IR 34%, P < 0.001) (percutaneous coronary intervention: STEMI 68.1%, NSTEACS-HR 22.2%, NSTEACS-IR 8.1%, P < 0.001). In hospital mortality was low (STEMI 4.0%, NSTEACS-HR 1.8%, NSTEACS-IR 0.1%, P < 0.001), as was recurrent MI (STEMI 2.4%, NSTEACS-HR: 2.8%, NSTEACS-IR 1.2%, P = 0.052). CONCLUSION: There appears to be an 'evidence-practice gap' in the management of ACS, but this is not matched by an increased risk of in-hospital clinical events. Objective evaluation of local clinical care is a key initial step in developing quality improvement initiatives and this study provides a basis for the improvement in ACS management in Australia.

Superiority of clopidogrel versus aspirin in patients with prior cardiac surgery.

BACKGROUND: After coronary artery bypass surgery, patients have a high cumulative rate of graft closure and recurrent ischemic events. We sought to determine whether antiplatelet therapy with clopidogrel would be more effective than aspirin, the accepted standard, in these patients. METHODS AND RESULTS: The event rates for all-cause mortality, vascular death, myocardial infarction, stroke, and rehospitalization were determined for the 1480 patients with a history of cardiac surgery randomized to either clopidogrel or aspirin in a trial of 19 185 patients. The event rate per year of vascular death, myocardial infarction, stroke, or rehospitalization was 22.3% in the 705 patients randomized to aspirin and 15.9% in the 775 patients randomized to clopidogrel (P:=0.001). A risk reduction was also seen in each of the individual end points examined, including a 42.8% relative risk reduction in vascular death in patients on clopidogrel versus aspirin (P:=0.030). In a multivariate model incorporating baseline clinical characteristics, clopidogrel therapy was independently associated with a decrease in vascular death, myocardial infarction, stroke, or rehospitalization in patients with a history of cardiac surgery, with a 31.2% relative risk reduction (95% CI, 15.8 to 43.8; P:=0.0003). Although clopidogrel therapy was efficacious in the entire Clopidogrel Versus Aspirin in Patients at Risk of Ischemic Events (CAPRIE) population, multivariate analysis demonstrated that patients with previous cardiac surgery derived particular benefit (P:=0.015). CONCLUSION: Compared with aspirin, clopidogrel therapy results in a striking reduction in the elevated risk for recurrent ischemic events seen in patients with a history of prior cardiac surgery, along with a decreased risk of bleeding.

Incremental prognostic value of elevated baseline C-reactive protein among established markers of risk in percutaneous coronary intervention.

BACKGROUND: Established methods of risk assessment in percutaneous coronary intervention have focused on clinical and anatomical lesion characteristics. Emerging evidence indicates the substantial contribution of inflammatory processes to short-term and long-term outcomes in coronary artery disease. METHODS AND RESULTS: Within a single-center registry of contemporary percutaneous coronary revascularization strategies with postprocedural creatine kinase and clinical events routinely recorded, we assessed the association of baseline C-reactive protein with death or myocardial infarction within the first 30 days. Predictive usefulness of baseline C-reactive protein within the context of established clinical and angiographic predictors of risk was also examined. Among 727 consecutive patients, elevated baseline C-reactive protein before percutaneous coronary intervention was associated with progressive increase in death or myocardial infarction at 30 days (lowest quartile, 3.9%, versus highest quartile, 14.2%; P=0.002). Among clinical and procedural characteristics, baseline C-reactive protein remained independently predictive of adverse events, with the highest quartile of C-reactive protein associated with an odds ratio for excess 30-day death or myocardial infarction of 3.68 (95% CI, 1.51 to 8.99; P=0.004). A predictive model that included baseline C-reactive protein quartiles, American College of Cardiology/American Heart Association lesion score, acute coronary syndrome presentation, and coronary stenting appears strongly predictive of 30-day death or myocardial infarction within this population (C-statistic, 0.735) and among individual patients (Brier score, 0.006). CONCLUSIONS: Elevated baseline C-reactive protein portends heightened risk of 30-day death or myocardial infarction after coronary intervention. Coupled anatomic, clinical, and inflammatory risk stratification demonstrates strong predictive utility among patients undergoing percutaneous coronary intervention and may be useful for guiding future strategies.

Defining the optimal activated clotting time during percutaneous coronary intervention: aggregate results from 6 randomized, controlled trials.

BACKGROUND: Unfractionated heparin has been the primary anticoagulant therapy for percutaneous coronary intervention for >20 years. Despite the availability of rapid "point of care" testing, little clinical data defining the optimal level of anticoagulation are available. Furthermore, recent reports have advocated the use of low-dose heparin regimens in the absence of large-scale, well-conducted studies to support this practice. METHODS AND RESULTS: We pooled the data from 6 randomized, controlled trials of novel adjunctive antithrombotic regimens for percutaneous coronary interventions in which unfractionated heparin constituted the control arm. Patients were divided into 25-s intervals of activated clotting times (ACTs), from <275 s to >476 s. In a total of 5216 patients, the incidence of death, myocardial infarction, or any revascularization and major or minor bleeding at 7 days were calculated for each group and compared. An ACT in the range of 350 to 375 s provided the lowest composite ischemic event rate of 6.6%, or a 34% relative risk reduction in 7-day ischemic events compared with rates observed between 171 and 295 s by quartile analysis (P=0.001). CONCLUSIONS: Contrary to recent reports, the optimal suppression of ischemic events with unfractionated heparin therapy in patients undergoing percutaneous coronary intervention demands treatment to ACT levels that are substantially higher than currently appreciated. These data define a goal for heparin dosing within coronary interventions and establish a benchmark of optimal unfractionated heparin therapy against which future trials of novel antithrombotic regimens in percutaneous interventions can be compared.

Platelet glycoprotein IIb/IIIa inhibitors reduce mortality in diabetic patients with non-ST-segment-elevation acute coronary syndromes.

BACKGROUND: Diabetes mellitus is a major risk factor for adverse outcomes after acute coronary syndromes (ACS). Because this disease may be associated with increased platelet aggregation, we investigated whether diabetic patients with ACS derive particular benefit from platelet glycoprotein (GP) IIb/IIIa receptor inhibition. METHODS AND RESULTS: We performed a meta-analysis of the diabetic populations enrolled in the 6 large-scale platelet GP IIb/IIIa inhibitor ACS trials: PRISM, PRISM-PLUS, PARAGON A, PARAGON B, PURSUIT, and GUSTO IV. Among 6458 diabetic patients, platelet GP IIb/IIIa inhibition was associated with a significant mortality reduction at 30 days, from 6.2% to 4.6% (OR 0.74; 95% CI 0.59 to 0.92; P=0.007). Conversely, 23 072 nondiabetic patients had no survival benefit (3.0% versus 3.0%). The interaction between platelet GP IIb/IIIa inhibition and diabetic status was statistically significant (P=0.036). Among 1279 diabetic patients undergoing percutaneous coronary intervention (PCI) during index hospitalization, the use of these agents was associated with a mortality reduction at 30 days from 4.0% to 1.2% (OR 0.30; 95% CI 0.14 to 0.69; P=0.002). CONCLUSIONS: This meta-analysis, including the entire large-scale trial experience of intravenous platelet GP IIb/IIIa inhibitors for the medical management of non-ST-segment-elevation ACS, shows that these agents may significantly reduce mortality at 30 days in diabetic patients. Although not based on a randomized assessment, the survival benefit appears to be of greater magnitude in patients undergoing PCI. Therefore, the use of platelet GP IIb/IIIa inhibitors should be strongly considered in diabetic patients with ACS.

A critical appraisal of platelet glycoprotein IIb/IIIa inhibition.

Despite the success of abciximab in preventing ischemic events after percutaneous coronary interventions, attempts to develop intravenous, small-molecule glycoprotein IIb/IIIa antagonists and diversify the clinical indications for these agents have produced varied results. The 30-day ischemic event reduction in the percutaneous coronary intervention trials has ranged by over three-fold (16% to 56%) and is greater among the acute coronary syndrome trials. The phase III trials exploring the role of oral glycoprotein IIb/IIIa inhibition have been consistently disappointing, with evolving evidence of increased mortality. Mechanisms contributing to these heterogeneous results may include normal variation in platelet or receptor number, differences in receptor activity, interpatient variation in pharmacological dose-response and the possibility of prothrombotic or nonglycoprotein IIb/IIIa effects. Plausibility of "suboptimal" effect is suggested by several recent studies. Trials investigating the role of intravenous small-molecule IIb/IIIa antagonists highlight the importance of effective dosing. The increase in bleeding and mortality observed in the oral glycoprotein IIb/IIIa studies indicate the consequences of suboptimal dosing on safety on one hand, while raising the possibility of important prothrombotic, counterregulatory or other sudden cardiac events. This article will undertake a review of the relevant platelet biology, discuss the mechanisms that may contribute to suboptimal antiplatelet efficacy with these agents and examine insights from the clinical trials supporting these concepts.

Oral glycoprotein IIb/IIIa inhibitors: why don't they work?

Despite their promise as orally active potent inhibitors of platelet aggregation, the oral platelet glycoprotein IIb/IIIa inhibitors have failed to provide a reduction in late ischemic events. In fact, with five large-scale randomized trials now complete, including over 42 000 patients, these agents have been associated with a surprising, yet consistent, excess in mortality. Peculiarly, this fatality risk has occurred in the absence of a commensurate increase in other ischemic end-points. While these findings have curtailed the further clinical development of this class of potent platelet inhibitors, the obvious dissociation between platelet suppression and adverse outcome requires further clarification. Multiple putative explanations for this excess in ischemic events with oral glycoprotein IIb/IIIa inhibitors have been proposed, but definitive data implicating a specific mechanism are currently not available. While the lack of concurrent aspirin may account for some of this effect, it is unlikely to fully explain the mortality excess. Potential mechanisms include partial agonist activity leading to increased expression of platelet-leukocyte adhesion molecules, sub-optimal inhibition of platelet aggregation, genetic polymorphisms, especially phospholipase A(2) polymorphism, and promotion of cardiac myocyte apoptosis via activation of caspase 3. Definitive elucidation of these adverse mechanisms will be required if further clinical development of the oral platelet glycoprotein IIb/IIIa inhibitors is to be pursued.

Dual antiplatelet therapy with clopidogrel and aspirin after carotid artery stenting.

BACKGROUND: Carotid artery stenting is being used as an alternative to carotid endarterectomy, both within the context of clinical trials and in non-surgical candidates. Though stenting is known to activate platelets, the role of antithrombotic therapy in carotid stenting has not been fully characterized. METHODS AND RESULTS: Consecutive patients (n = 162) were followed in a single-center carotid stent registry. The cumulative rate of 30-day death, stroke, transient ischemic attack and myocardial infarction in those patients receiving a thienopyridine was determined, as were rates of stent thrombosis and intracranial hemorrhage. The mean age of the patients was 70.3 years and there was an extremely high prevalence of cardiovascular comorbidities, including 40% with unstable angina. The carotid lesion was symptomatic in 59% of patients. The average pre-treatment stenosis was 83%. The cumulative 30-day rate of death, stroke, transient ischemic attack and myocardial infarction was 5.6%. Specifically, in the patients who received ticlopidine (n = 23), the rate was 13%, versus 4.3% in the patients who received clopidogrel (n = 139) (p = 0.01). In this series, there were no cases of stent thrombosis and 1 intracranial hemorrhage. CONCLUSION: Dual antiplatelet therapy with clopidogrel plus aspirin in patients receiving carotid artery stents is associated with a low rate of ischemic events. Furthermore, clopidogrel appears superior to ticlopidine. Thus, our findings lend support to the dual antiplatelet strategy of clopidogrel plus aspirin for patients undergoing carotid artery stenting.

GP IIb/IIIa inhibitors in coronary artery disease management: what the latest trials tell us.

Recent clinical trials have refined our understanding of how the glycoprotein (GP) IIb/IIIa inhibitors should best be used. These trials examined whether there are clinical differences between agents, whether empiric use of GP IIb/IIIa inhibitors in acute coronary syndromes is justified, and whether these drugs might allow for early invasive management in acute coronary syndromes.

Bivalirudin, a bivalent, thrombin specific anticoagulant as an alternative to heparin in interventional procedures as an alternative to heparin in interventional procedures.

Among the antithrombotic therapies evaluated to date, the synthetic peptide bivalirudin is unique in its ability to reduce both ischemic and bleeding complications associated with percutaneous coronary intervention (PCI). Bivalirudin is a small peptide consisting of 20 amino acid residues that binds thrombin in a direct, reversible, and bivalent fashion. The agent is approved for use in the United States and New Zealand as an anticoagulant in patients with unstable angina undergoing PCI and may also prove beneficial in patients with acute coronary syndromes (ACS), acute myocardial infarction (AMI) and in patients undergoing coronary artery bypass graft (CABG) procedures. This article examines bivalirudin in more detail.

Initial experience with the balloon expandable Edwards-SAPIEN Transcatheter Heart Valve in Australia and New Zealand: the SOURCE ANZ registry: outcomes at 30 days and one year.

BACKGROUND: We report the findings of the SOURCE-ANZ registry of the clinical outcomes of the Edwards SAPIEN™ Transcatheter Heart Valve (THV) in the Australian and New Zealand (ANZ) clinical environment. METHODS: This single arm registry of select patients treated in eight centres, represent the initial experience within ANZ with the balloon expandable Edwards SAPIEN THV delivered by transfemoral (TF) and transapical (TA) access. RESULTS: The total enrolment for the study was 132 patients, 63 patients treated by TF, 56 by TA, and 2 patients were withdrawn from the study. The mean ages: 83.7 (TF) and 81.7 (TA), female: 34.3% (TF) and 61.3% (TA), logistic EuroSCORE: 26.8% (TF) and 28.8% (TA), and with procedural success (successful implant without conversion to surgery or death): 92.4% (TF) and 87.1% (TA) (p=0.32). Outcomes were not significantly different between TF and TA implants. These included one year mortality of 13.6% (TF) and 21.7% (TA) (p=0.24), MACCE: 16.7% (TF) and 28.3% (TA) (p=0.12), pacemaker: 4.6% (TF) and 8.3% (TA) (p=0.39), and VARC major vascular complication of 4.6% (TF) and 5.0% (TA) (p=0.91). CONCLUSION: TAVI in the ANZ clinical environment has demonstrated excellent outcomes for both the TA and TF approaches in highly selected patients. These results are consistent with those demonstrated in European, Canadian registries and the pivotal US clinical trials. ACTRN12611001026910.