Primary Percutaneous Coronary Intervention and Application of the Pharmacoinvasive Approach Within ST-Elevation Myocardial Infarction Care Networks.

The management of acute ST-elevation myocardial infarction (STEMI) has transitioned from observation and reactive treatment of hemodynamic and arrhythmic complications to accelerated reperfusion and application of evidence-based treatment to minimize morbidity and mortality. International research established the importance of timely reperfusion therapy and the application of fibrinolysis, primary percutaneous coronary intervention (PCI), and subsequent development of the pharmacoinvasive approach. Clinician thought leaders developed and investigated comprehensive systems of care to optimize the outcomes of patients with STEMI, with a key focus in Canada being the integration of prehospital paramedics in diagnosis, triage, and treatment. This article will review highlights of these interventions and identify future challenges and opportunities in STEMI patient care.

Risk Prediction Models for Contrast-Induced Acute Kidney Injury Accompanying Cardiac Catheterization: Systematic Review and Meta-analysis.

BACKGROUND: Identification of patients at risk of contrast-induced acute kidney injury (CI-AKI) is valuable for targeted prevention strategies accompanying cardiac catheterization. METHODS: We searched MedLine and EMBASE for articles that developed or validated a clinical prediction model for CI-AKI or dialysis after angiography or percutaneous coronary intervention. Random effects meta-analysis was used to pool c-statistics of models. Heterogeneity was explored using stratified analyses and meta-regression. RESULTS: We identified 75 articles describing 74 models predicting CI-AKI, 10 predicting CI-AKI and dialysis, and 1 predicting dialysis. Sixty-three developed a new risk model whereas 20 articles reported external validation of previously developed models. Thirty models included sufficient information to obtain individual patient risk estimates; 9 using only preprocedure variables whereas 21 included preprocedural and postprocedure variables. There was heterogeneity in the discrimination of CI-AKI prediction models (median [total range] in c-statistic 0.78 [0.57-0.95]; I2 = 95.8%, Cochran Q-statistic P < 0.001). However, there was no difference in the discrimination of models using only preprocedure variables compared with models that included postprocedural variables (P = 0.868). Models predicting dialysis had good discrimination without heterogeneity (median [total range] c-statistic: 0.88 [0.87-0.89]; I2 = 0.0%, Cochran Q-statistic P = 0.981). Seven prediction models were externally validated; however, 2 of these models showed heterogeneous discriminative performance and 2 others lacked information on calibration in external cohorts. CONCLUSIONS: Three published models were identified that produced generalizable risk estimates for predicting CI-AKI. Further research is needed to evaluate the effect of their implementation in clinical care.

Cirrhotic cardiomyopathy: Implications for liver transplantation.

The majority of patients on a waiting list for liver transplantation have end-stage liver disease. Because of the marked peripheral vasodilatation of end-stage cirrhosis that masks a latent myocardial dysfunction, cardiac abnormalities in the resting state are usually subclinical and escape the attention of physicians. However, when challenged, the systolic and diastolic contractile responses are attenuated. In addition to these contractile abnormalities, morphological changes, such as enlargement or hypertrophy of cardiac chambers, and electrophysiological repolarization changes, including a prolonged QT interval, can be observed. The constellation of these cardiac abnormalities is termed cirrhotic cardiomyopathy. Liver transplantation induces significant cardiovascular stress. Clamping of the inferior vena cava and portal vein, hemorrhage and blood/volume infusion, and ischemia/reperfusion all cause hemodynamic fluctuation. The changing cardiac preload and afterload status increases the cardiac workload, and thus, the previously subclinical ventricular dysfunction may manifest as overt heart failure during the operative and perioperative periods. Cardiac dysfunction contributes to morbidity and mortality associated with liver transplantation. Cardiovascular events are the third leading cause of death in liver recipients. However, because liver transplantation is the only definitive treatment for end-stage liver failure and also appears to reverse cardiac abnormalities, it is important to understand the challenges of the heart in liver transplantation. This review focuses on cardiac status before, during, and after liver transplantation. Liver Transplantation 23 826-835 2017 AASLD.

Structural Heart Disease Intervention: The Canadian Landscape.

Cardiovascular disease encompasses coronary artery disease and valvular heart disease, and the prevalence of both increases with age. Over the past decade, the landscape of interventional cardiology has evolved to encompass a new set of percutaneous procedures outside the coronary tree, including transcatheter aortic valve implantation, transcatheter mitral valve repair, and left atrial appendage occlusion. These interventions have sparked a new discipline within interventional cardiology referred to as structural heart disease (SHD) intervention. The access to and numbers of such procedures performed in Canada is currently unknown. This "first of its kind" survey of structural interventions provides insight into the landscape of SHD intervention in Canada and the challenges faced by cardiologists to deliver this important care.

Ischemic postconditioning does not improve peripheral endothelial function in ST-segment elevation myocardial infarction patients.

The purpose of this study was to determine whether ischemic postconditioning (IPC) could improve peripheral endothelial function in patients with acute ST-segment elevation myocardial infarction (STEMI) undergoing primary percutaneous coronary intervention (PCI). Of 102 patients randomly assigned to an IPC or standard protocol to study infarct size utilizing cardiovascular magnetic resonance imaging, 84 patients had peripheral endothelial function assessed with brachial ultrasound measures and peripheral arterial tonometry (PAT) during reactive hyperemia 3 days after PCI. Overall IPC was not associated with a smaller infarct size compared to controls, though there was a trend towards greater myocardial salvage with IPC. Patients randomized to IPC (n=43; age 56 ± 11 years; 85% male) and standard protocol (n=41; age 56 ± 10 years; 88% male) underwent endothelial function assessment. Flow mediated vasodilatation was not significantly greater in the IPC group than in the standard group (7.4 ± 4.9% versus 6.6 ± 4.0% respectively, p=0.40) nor was peak hyperemic velocity-time integral (78 ± 26 cm versus 71 ± 30 cm respectively, p=0.28). Similarly, the PAT hyperemic ratio was not significantly greater in the IPC group than in the standard group (2.0 ± 0.9 versus 1.8 ± 0.6 respectively, p=0.14). In conclusion, IPC did not improve early peripheral endothelial function in patients with STEMI undergoing primary PCI.

No cardioprotective benefit of ischemic postconditioning in patients with ST-segment elevation myocardial infarction.

BACKGROUND: Postconditioning is a potential cardioprotective strategy that has demonstrated conflicting and variable reductions in infarct size in human trials. OBJECTIVES: To determine whether postconditioning could increase the extent of myocardial salvage in patients with acute ST-segment elevation myocardial infarction undergoing primary percutaneous coronary intervention (PPCI). METHODS: One hundred two patients (aged 57 ± 11 years; 88% male) were randomly assigned to a postconditioning or standard protocol. Cardiovascular magnetic resonance imaging was performed 3 days after PPCI to measure the volumetric extent of myocardial necrosis and the area at risk. RESULTS: With similar time-to-reperfusion (170 ± 84 minutes in the postconditioning group vs. 150 ± 70 minutes in the standard group, P = 0.22), the myocardial salvage index was not significantly different between the postconditioned group and the control group, averaging 42 ± 22% vs. 33 ± 21%, respectively (P = 0.08). Furthermore, postconditioning was not associated with a smaller infarct size compared to controls (13 ± 7 g/m(2) vs. 15 ± 8 g/m(2), respectively, P = 0.18). CONCLUSIONS: Postconditioning does not significantly increase myocardial salvage or reduce infarct size in patients with STEMI undergoing PPCI. However, the possibility of a more modest impact of postconditioning cannot be excluded with our sample size.

Canadian Cardiovascular Society position statement on radiation exposure from cardiac imaging and interventional procedures.

Exposure to ionizing radiation is a consequence of many diagnostic and interventional cardiac procedures. Radiation exposure can result in detrimental health effects because of deterministic (eg, skin reaction) and stochastic effects (eg, cancer). However, with the levels experienced during cardiac procedures these risks can be difficult to quantify. Healthcare providers and patients might not fully appreciate radiation-related risks. Though in many cases radiation exposure cannot be avoided, a practice of minimizing exposures to levels "as low as reasonably achievable" (ALARA principle) without compromising the utility of the procedure is encouraged. The purpose of this document is to inform health care providers on the key concepts related to radiation risk from common cardiac procedures and provide specific recommendations on ensuring quality of care.

Temporal associations of early patient transfers and mortality with the implementation of a regional myocardial infarction care model.

BACKGROUND: In order to reduce the delays encountered through patient transfer, regional care models have been developed that directly transport subsets of acute myocardial infarction (AMI) patients to hospitals with percutaneous coronary intervention (PCI) facilities. Calgary is a Canadian city that implemented this type of model in 2004. METHODS: The study population included 9768 AMI patients admitted to Calgary hospitals between 1997 and 2007. Administrative data were used to define patients who were directly admitted to the PCI hospital and those transferred there after initial admission to a hospital without specialized cardiac care. The differences in clinical characteristics and mortality trends of patients grouped by hospital delivery site and transfer practice are described. RESULTS: The proportion of patients directly admitted to a PCI hospital has increased with the implementation of a regional care model. Among patients admitted to non-PCI facilities, the patients who are transferred are younger, more likely to be male, have a shorter length of stay, and have lower proportions of several comorbid conditions. The risk-adjusted in-hospital mortality odds ratio for patients who received care at the PCI hospital postmodel relative to those treated at non-PCI hospitals premodel was 0.38 (95% confidence interval, 0.31-0.47). The corresponding adjusted odds ratio was 0.60 (0.47-0.76). CONCLUSIONS: Our results suggest changing care over time and trends toward improved outcomes. Patients' clinical characteristics appear to play a major role in the decision to transfer. Avoidance of the risk treatment paradox through refinement of regional transfer protocols ought to be a priority.

An early cardiac access clinic significantly improves cardiac rehabilitation participation and completion rates in low-risk ST-elevation myocardial infarction patients.

BACKGROUND: Survivors of an acute ST-elevation myocardial infarction (STEMI) remain at high risk for future cardiac events. Cardiac rehabilitation (CR) participation significantly reduces coronary artery disease (CAD) morbidity and mortality risk. Regrettably, poor utilization of CR services post STEMI is common, accentuating a critical action gap in the trajectory of CAD management. The objective of this study was to determine whether integration of an early cardiac access clinic (ECAC), held within 4-14 days of hospital discharge, could improve CR utilization rates following an STEMI. METHODS: Between January 2008 and July 2009, 245 consecutively admitted STEMI patients (19.6% female) deemed low risk following early re-establishment of coronary blood flow, were assigned to the ECAC model. An historic comparison group (n=224) was identified based on all STEMI patient admissions at the same tertiary care facility during the 2007 calendar year that met ECAC eligibility criteria. The primary outcomes were rates of CR referral, orientation attendance, program participation, and completion. RESULTS: The ECAC cohort had significantly higher rates of CR referral (100% vs 55.8%, P < 0.0001), orientation attendance (96.3 vs 37.1%, P < 0.0001), program participation (87.8% vs 33.5%, P < 0.0001), and completion (71.4% vs 29.9%, P < 0.001) compared to the matched historical comparison group. CONCLUSIONS: The utilization of the ECAC model resulted in an unprecedented (∼3-fold) increase in the number of post-STEMI patients participating in CR. Given the unequivocal mortality and morbidity benefits of CR, adoption of the ECAC model has important clinical and economic relevance.

Outcomes of after-hours versus regular working hours primary percutaneous coronary intervention for acute myocardial infarction.

BACKGROUND: Primary percutaneous coronary intervention (PCI) is a proven therapy for acute ST-segment elevation myocardial infarction. However, outcomes associated with primary PCI may differ depending on time of day. METHODS AND RESULTS: Using the Alberta Provincial Project for Outcomes Assessment in Coronary Heart Disease, a clinical data-collection initiative capturing all cardiac catheterisation patients in Alberta, Canada, the authors described and compared crude and risk-adjusted survival for ST-segment elevation myocardial infarction patients undergoing primary PCI after-hours versus regular working hours. From 1 January 1999 to 31 March 2006, 1664 primary PCI procedures were performed (54.4% after-hours). Mortalities at 30days were 3.6% for regular hours procedures and 5.0% for after-hours procedures (p=0.16). 1-year mortalities were 6.2% and 7.3% in the regular hours and after-hours groups, respectively (p=0.35). After adjusting for baseline risk factor differences, HRs for after-hours mortality were 1.26 (95% CI 0.78 to 2.02) for survival to 30days and 1.08 (0.73 to 1.59) for survival to 1year. A meta-analysis of our after-hours HR point estimate with other published risk estimates for after hours primary PCI outcomes yielded an RR of 1.23 (1.00 to 1.51) for shorter-term outcomes. CONCLUSIONS: After-hours primary PCI was not associated with a statistically significant increase in mortality. However, a meta-analysis of this study with other published after-hours outcome studies yields an RR that leaves some questions about unexplored factors that may influence after-hours primary PCI care.

Long-term outcomes of patients receiving drug-eluting stents.

BACKGROUND: We sought to establish the long-term safety of drug-eluting stents compared with bare-metal stents in a usual care setting. METHODS: Using data from a prospective multicentre registry, we compared rates of death and of death or repeat revascularization during 3 years of follow-up of 6440 consecutive patients who underwent angioplasty with either drug-eluting or bare-metal stents between Apr. 1, 2003, and Mar. 31, 2006. RESULTS: Drug-eluting stents were inserted in 1120 patients and bare-metal stents in 5320. The drug-eluting stents were selected for patients who had a greater burden of comorbid illness, including diabetes mellitus (32.8% v. 20.8% in the bare-metal group, p < 0.001) and renal disease (7.4% v. 5.0%, p = 0.001). At 1-year follow-up, the drug-eluting stents were associated with a mortality of 3.0%, as compared with 3.7% with the bare-metal stents (adjusted odds ratio [OR] 0.62, 95% confidence interval [CI] 0.46-0.83). The rate of the composite outcome of death or repeat revascularization was 12.0% for the drug-eluting stents and 15.8% for the bare-metal stents (adjusted OR 0.40, 95% CI 0.33-0.49). In the subgroup of patients who had acute coronary syndromes, the adjusted OR for this composite outcome was 0.46 (95% CI 0.35-0.61). During the 3 years of observation, the relative risks for death and repeat revascularization varied over time. In year 1, there was an initial period of lower risk in the group with drug-eluting stents than in the group with bare-metal stents; this was followed by a shift toward outcome rates favouring bare-metal stents in years 2 and 3. The adjusted relative risk of the composite outcome of death or repeat revascularization associated with drug-eluting stents relative to bare-metal stents was 0.73 early in the first year of follow-up; it then rose gradually over time, to a peak of 2.24 at 3 years. INTERPRETATION: Drug-eluting stents are safe and effective in the first year following insertion. Thereafter, the possibility of longer term adverse events cannot be ruled out.

Coronary dominance and prognosis of patients with acute coronary syndrome.

BACKGROUND: A number of studies have identified the number of diseased vessels to be an important determinant of survival in patients with acute coronary syndrome (ACS). It is unknown if coronary dominance has an impact on prognosis of these patients. We hypothesized that the prognosis of patients with ACS with left dominance (LD) would be worse than that of patients with right or mixed dominance. METHODS: The study population consisted of 27,289 patients whose primary indication for cardiac catheterization was ACS. The patients were divided into 3 groups according to coronary dominance. The mean duration of follow-up was 3.5 years (range 1-6.5 years). A Cox proportional hazards analysis was used to compare survival by dominance, adjusting for age, sex, diagnosis, comorbidities, severity of coronary disease, and ejection fraction. RESULTS: The rates and patterns of revascularization among patients with significant coronary disease were similar between the groups. At the end of follow-up, patients with LD had a significantly higher mortality (hazard ratio 1.18, 95% CI 1.05-1.34; adjusted hazard ratio 1.13, CI 1.00-1.28). The mortality of patients with mixed and right dominance was similar. CONCLUSION: In patients with ACS, LD is a significant and independent predictor of increased long-term mortality. Further research is needed to determine mechanisms of increased mortality in patients with LD and measures that can be taken to improve the outcome of patients with left-dominant circulation.

Prognostic implication of hyperglycemia in myocardial infarction and primary angioplasty.

PURPOSE: The study assessed the relationship of admission blood glucose level to in-hospital mortality in patients presenting with an ST-segment elevation myocardial infarction and treated with primary angioplasty. METHODS: A total of 980 patients presenting with an ST-segment elevation myocardial infarction and treated exclusively with primary angioplasty were evaluated. Patients were divided into quartiles based on their admission blood glucose level: group 1 (< or =6.6 mmol/L [< or =119 mg/dL]), group 2 (6.7-7.8 mmol/L [120-140 mg/dL]), group 3 (7.9-10.0 mmol/L [141-180 mg/dL], and group 4 (> or =10.1 mmol/L [> or =181 mg/dL]. The primary end point was in-hospital mortality. RESULTS: The mean age of the patient cohort was 62 years, 260 (27%) of whom were female. The mean admission blood glucose level was 9.1+/-4.4 mmol/L (164+/-79 mg/dL). At admission, 16% of this group were known to have diabetes. The in-hospital mortality rate was 3.8% (n=37), 5.2% in the diabetic group (n=8) and 3.5% (n=29) in the nondiabetic group. In-hospital mortality rates were significantly increased in patients with an elevated admission blood glucose level (P<.001). The in-hospital deaths in each admission blood glucose level quartile were 0.4% (n=1) in group 1, 2% (n=6) in group 2, 2% (n=6) in group 3, and 10% (n=24) in group 4. CONCLUSIONS: In this cohort of patients who were admitted with an ST-segment elevation myocardial infarction and treated exclusively with primary angioplasty, elevated admission blood glucose level is significantly associated with an increase in in-hospital mortality.

Expedited transfer for primary percutaneous coronary intervention: a program evaluation.

BACKGROUND: A shorter time from symptom onset to reperfusion is associated with improved outcomes for patients with ST-segment elevation myocardial infarction (MI). Primary percutaneous coronary intervention is a favourable method of reperfusion if performed effectively and expeditiously. We sought to evaluate the impact of an expedited pre-hospital diagnosis and transfer pathway developed by a multidisciplinary team on the door-to-balloon time in a large urban community. METHODS: We included all patients with ST-segment elevation MI who presented within 12 hours after symptom onset and who sought medical attention through Emergency Medical Services within the boundaries of the city of Calgary in the 16 months following the introduction of the pathway in June 2004. The primary aim was to determine the proportion of patients who received percutaneous coronary intervention within the recommended door-to-balloon time of 90 minutes. RESULTS: The 358 patients (268 men) in the study cohort had a mean age of 63.2 (standard deviation 12.7) years; 140 (39.1%) had an anterior MI; and 23 (6.4%) had cardiogenic shock. The introduction of the pathway resulted in a median door-to-balloon time of 62 (interquartile range 45-84) minutes. A door-to-balloon time within 60 minutes and within the currently recommended 90 minutes was achieved in 48.9% and 78.8% of the patients respectively. The in-hospital and 30-day mortality rates were both 3.1%. INTERPRETATION: In a community with multiple regional hospitals and a single facility for percutaneous coronary intervention, the implementation of a multidisciplinary pre-hospital diagnosis and transfer pathway was feasible and resulted in most patients in the study cohort receiving primary percutaneous coronary intervention within the recommended door-to-balloon time of 90 minutes.

Registry data evaluating the effectiveness of drug-eluting stents for the treatment of symptomatic in-stent restenosis.

BACKGROUND: In this new-era of drug-eluting stents (DES) the impact of symptomatic in-stent restenosis (ISR) is diminishing. However, world wide bare-metal stents remain widely used and therefore, it is imperative to establish a simple and effective form of treatment. The objective of this registry database was to evaluate the 'real-world' effectiveness of DES for the treatment of symptomatic bare-metal stent ISR. METHODS: All patients presenting with symptomatic ISR were evaluated between February 2003 and February 2005. Patients had 9-month angiographic follow-up with primary endpoint evaluation of binary restenosis (>50%). Secondary endpoints included in-segment late loss, target lesion revascularization (TLR) and the difference in late loss between sirolimus (n=23) and paciltaxel (n=36) eluting stents. RESULTS: Fifty eight patients with fifty nine ISR lesions were evaluated, 36% of patients had diabetes mellitus. All procedures were performed safely with no adverse peri-procedural events documented. At 9-month follow-up the median in-segment late loss was 0.24 mm (IQR 0.1, 0.53), with a binary restenosis rate of 17%. At long-term follow-up greater than 1 year, the incidence of TLR was 10%. No difference in the angiographic parameter of in-segment late loss was seen between the sirolimus and paclitaxel-eluting stents. CONCLUSIONS: In this cohort of patients with long-term angiographic and clinical follow-up, DES is an effective and safe treatment for symptomatic bare-metal stent ISR.

Effect of percutaneous coronary intervention of nonacute total coronary artery occlusions on QT dispersion.

BACKGROUND: Myocardial ischemia is one of several potential causes of increased QT dispersion (QTd) in patients with nonacute total coronary artery occlusions (TCOs). We sought to assess the effect of percutaneous revascularization (PCI) of TCO on QTd and the relationship between QTd and long-term vessel patency. METHODS: Seventy patients enrolled in the TOSCA were analyzed. Patients were undergoing PCI of a TCO > 72 hours' duration. Two independent reviewers measured QTd from electrocardiograms done immediately before PCI (PRE), 12 to 18 hours after PCI (POST), and then at 6 months (6M). Follow-up angiography was performed at 6 months. RESULTS: Mean QTd decreased from PRE (77 +/- 29 milliseconds) to POST (66 +/- 26 milliseconds, P < .001) and 6M (65 +/- 25 milliseconds, P < .001). Patients with the same or longer QTd at 6 months compared with POST (POST < or = 6M) had significantly higher risk of failed target-vessel patency (odds ratio 10.3, 95% CI 1.24-84.8) than patients with QTd reduction at 6M versus POST values. CONCLUSION: Revascularization of TCO resulted in a decrease in QTd, which was sustained at 6M. This suggests that PCI to a TCO has a beneficial effect on stabilization of the underlying ischemic substrate. Furthermore, absence of QTd reduction at 6M versus POST was associated with increased risk of failed target-vessel patency.

The Canadian study of the sirolimus-eluting stent in the treatment of patients with long de novo lesions in small native coronary arteries (C-SIRIUS).

OBJECTIVES: We assessed the safety and effectiveness of the sirolimus-eluting stent (SES) in treating single de novo long lesions in small native coronary arteries compared to an identical bare metal stent (BMS). BACKGROUND: The SES was previously demonstrated to reduce restenosis significantly. However, patients with long lesions in small vessels have not been well studied and may define a group at very high risk. METHODS: The Canadian Study of the Sirolimus-Eluting Stent in the Treatment of Patients With Long De Novo Lesions in Small Native Coronary Arteries (C-SIRIUS) was a multicenter, randomized, double-blind trial comparing SES versus identical BMS. The primary end point was in-stent minimal lumen diameter (MLD) at eight months. Secondary end points included angiographic restenosis at 8 months, target lesion revascularization (TLR), and major adverse cardiac events (MACE) at 270 days. RESULTS: A total of 100 patients were enrolled at eight Canadian sites. The in-stent MLD at eight months was 2.46 +/- 0.37 mm in the SES compared with 1.49 +/- 0.75 mm in the BMS (a 65% increase, p < 0.001). Angiographic restenosis occurred in 1 of 44 SES patients (2.3%, with no in-stent restenosis) and in 23 of 44 BMS patients (52.3%, p < 0.001). At 270 days, there were two clinically driven TLRs in the SES (4%) and nine in the BMS (18%, p = 0.05). The Kaplan-Meier estimate of freedom from MACE at 270 days was 96.0% for SES patients and 81.7% for BMS patients (p = 0.029). CONCLUSIONS: Patients with long lesions in small vessels are at very high risk of restenosis. In these patients, the SES dramatically reduces the risk of restenosis at eight months, translating into an excellent clinical outcome at nine months.