M. Yudi

Catheter‐Tissue Contact Force Determines Atrial Electrogram Characteristics Before and Lesion Efficacy After Antral Pulmonary Vein Isolation in Humans

Electrogram (EGM) characteristics are used to infer catheter‐tissue contact. We examined if (a) atrial EGM characteristics predicted CF and (b) compared the value of CF versus other surrogates for predicting lesion efficacy.

Predictive value of impedance changes for real-time contact force measurements during catheter ablation of atrial arrhythmias in humans

BACKGROUND Catheter-tissue contact force (CF) determines radiofrequency (RF) ablation lesion size. Impedance changes during RF delivery are used as surrogate markers for CF. The relationship between impedance and real-time CF in humans remains unknown. OBJECTIVES To determine whether impedance changes have predictive value for real-time CF during catheter ablation of atrial arrhythmias. METHODS Real-time CF, force-time integral, and impedance were measured in 2265 RF lesions for atrial fibrillation or flutter in 34 patients. Operators were blinded to CF measurements. Impedance preablation, at 5-second intervals for 30 seconds after the RF onset, maximal impedance fall and time to impedance plateau during RF were correlated with CF. Average CF was divided into low (≤20 g), intermediate (21-60 g), and high (>60 g) categories. RESULTS Preablation impedance poorly correlated with preablation CF (R = .07). Maximal impedance fall modestly correlated with average CF and force-time integral (R = .32 and .37, respectively). There was a large degree of overlap in impedance fall between different CF categories. A maximal impedance fall of 10 Ω could predict average CF of >20 g, with a sensitivity and specificity of 71% and 53% and a positive and negative predictive value of 51% and 49%, respectively. Impedance fall was only able to differentiate between different CF categories ≥15 seconds after the RF onset. Higher CFs moderately correlated with delayed plateau in impedance (R = .41). CONCLUSIONS Impedance measurements (both baseline and impedance fall) are, at best, moderately efficacious as surrogate markers for predicting real-time catheter-tissue CF. These findings highlight the importance of real-time CF measurements, rather than impedance changes to optimize ablation efficacy.

Clopidogrel, Prasugrel or Ticagrelor in Patients with Acute Coronary Syndromes undergoing Percutaneous Coronary Intervention.

Guidelines recommend prasugrel or ticagrelor instead of clopidogrel in patients with acute coronary syndromes (ACS) undergoing percutaneous coronary interventions (PCI).

SMARTphone-based, early cardiac REHABilitation in patients with acute coronary syndromes [SMART-REHAB Trial]: a randomized controlled trial protocol

BackgroundThere are well-documented treatment gaps in secondary prevention of coronary heart disease and no clear guidelines to assist early physical activity after acute coronary syndromes (ACS). Smartphone technology may provide an innovative platform to close these gaps. This paper describes the study design of a randomized controlled trial assessing whether a smartphone-based secondary prevention program can facilitate early physical activity and improve cardiovascular health in patients with ACS.MethodsWe have developed a multi-faceted, patient-centred smartphone-based secondary prevention program emphasizing early physical activity with a graduated walking program initiated on discharge from ACS admission. The program incorporates; physical activity tracking through the smartphone’s accelerometer with interactive feedback and goal setting; a dynamic dashboard to review and optimize cardiovascular risk factors; educational messages delivered twice weekly; a photographic food diary; pharmacotherapy review; and support through a short message service. The primary endpoint of the trial is change in exercise capacity, as measured by the change in six-minute walk test distance at 8-weeks when compared to baseline. Secondary endpoints include improvements in cardiovascular risk factor status, psychological well-being and quality of life, medication adherence, uptake of cardiac rehabilitation and re-hospitalizations.DiscussionThis randomized controlled trial will use a smartphone-phone based secondary prevention program to emphasize early physical activity post-ACS. It will provide evidence regarding the feasibility and utility of this innovative platform in closing the treatment gaps in secondary prevention.Trial registrationThe trial was retrospectively registered in the Australian New Zealand Clinical Trials Registry (ANZCTR) on April 4, 2016. The registration number is ACTRN12616000426482.

The prognostic significance of smoking cessation after acute coronary syndromes: an observational, multicentre study from the Melbourne interventional group registry

Objective We aim to ascertain the prognostic significance of persistent smoking and smoking cessation after an acute coronary syndrome (ACS) in the era of percutaneous coronary intervention (PCI) and optimal secondary prevention pharmacotherapy. Methods Consecutive patients from the Melbourne Interventional Group registry (2005–2013) who were alive at 30 days post-ACS presentation were included in our observational cohort study. Patients were divided into four categories based on their smoking status: non-smoker; ex-smoker (quit >1 month before ACS); recent quitter (smoker at presentation but quit by 30 days) and persistent smoker (smoker at presentation and at 30 days). The primary endpoint was survival ascertained through the Australian National Death Index linkage. A Cox-proportional hazards model was used to estimate the adjusted HR and 95% CI for survival. Results Of the 9375 patients included, 2728 (29.1%) never smoked, 3712 (39.6%) were ex-smokers, 1612 (17.2%) were recent quitters and 1323 (14.1%) were persistent smokers. Cox-proportional hazard modelling revealed, compared with those who had never smoked, that persistent smoking (HR 1.78, 95% CI 1.36 to 2.32, p<0.001) was an independent predictor of increased hazard (mean follow-up 3.9±2.2 years) while being a recent quitter (HR 1.27, 95% CI 0.96 to 1.68, p=0.10) or an ex-smoker (HR 1.03, 95% CI 0.87 to 1.22, p=0.72) were not. Conclusions In a contemporary cohort of patients with ACS, those who continued to smoke had an 80% risk of lower survival while those who quit had comparable survival to lifelong non-smokers. This underscores the importance of smoking cessation in secondary prevention despite the improvement in management of ACS with PCI and pharmacotherapy.

Impact of door-to-balloon time on long-term mortality in high- and low-risk patients with ST-elevation myocardial infarction

BACKGROUND Door-to-balloon time (DTBT) less than 90min remains the benchmark of timely reperfusion in ST-elevation myocardial infarction (STEMI). The relative long-term benefit of timely reperfusion in STEMI patients with differing risk profiles is less certain. Thus, we aimed to assess the impact of DTBT on long-term mortality in high- and low-risk STEMI patients. METHOD We analysed baseline clinical and procedural characteristics of 2539 consecutive STEMI patients who underwent primary percutaneous coronary intervention (PCI) from the Melbourne Interventional Group registry from 2004 to 2012. Patients were classified high risk (HR-STEMI) if they presented with cardiogenic shock, out-of-hospital cardiac arrest (OHCA) or Killip class ≥2; or low-risk (LR-STEMI) if there were no high-risk features. We then stratified high- and low-risk patients by DTBT (≤90min vs. >90min) and assessed long-term mortality. RESULT Of the 2539 patients, 395 (16%) met the high-risk criteria. A DTBT ≤90min was achieved in 43% of HR-STEMI patients and in 55% of LR-STEMI patients. Patients in the HR-STEMI compared to LR-STEMI cohort had higher in-hospital (31% vs. 1%, p<0.01) and long-term mortality (37% vs. 7%, p<0.01). A DTBT ≤90min was associated with significant improvements in short- and long-term mortality in both groups. A DTBT ≤90min was an independent multivariate predictor of long-term survival in LR-STEMI (hazard ratio [HR] 0.5, 95% confidence interval [CI] 0.3-0.9, p=0.02) but not in HR-STEMI (HR 0.7, 95% CI 0.5-1.1, p=0.11). CONCLUSION A DTBT ≤90min was associated with improved short- and long-term outcomes in high- and low-risk STEMI patients. However, it was only an independent predictor of long-term survival in LR-STEMI patients.

Trends and Impact of Door-to-Balloon Time on Clinical Outcomes in Patients Aged <75, 75 to 84, and ≥85 Years With ST-Elevation Myocardial Infarction.

Guidelines strongly recommend patients with ST-elevation myocardial infarction (STEMI) receive timely mechanical reperfusion, defined as door-to-balloon time (DTBT) ≤90 minutes. The impact of timely reperfusion on clinical outcomes in patients aged 75-84 and ≥85 years is uncertain. We analysed 2,972 consecutive STEMI patients who underwent primary percutaneous coronary intervention from the Melbourne Interventional Group Registry (2005-2014). Patients aged <75 years were included in the younger group, those aged 75-84 years were in the elderly group and those ≥85 years were in the very elderly group. The primary endpoints were 12-month mortality and major adverse cardiovascular events (MACE). 2,307 (77.6%) patients were <75 years (mean age 59 ± 9 years), 495 (16.7%) were 75-84 years and 170 (5.7%) were ≥85 years. There has been a significant decrease in DTBT over 10 years in younger and elderly patients (p-for-trend <0.01 and 0.03) with a trend in the very elderly (p-for-trend 0.08). Compared to younger and elderly patients, the very elderly had higher 12-month mortality (3.6% vs 10.7% vs. 29.4%; p = 0.001) and MACE (10.8% vs 20.6% vs 33.5%; p = 0.001). DTBT ≤90 minutes was associated with improved outcomes on univariate analysis but was not an independent predictor of improved 12-month mortality (OR 0.84, 95% CI 0.54-1.31) or MACE (OR 0.89, 95% CI 0.67-1.16). In conclusion, over a 10-year period, there was an improvement in DTBT in patients aged <75 years and 75-84 years however DTBT ≤90 minutes was not an independent predictor of 12-month outcomes. Thus assessing whether patients aged ≥85 years are suitable for invasive management does not necessarily translate to worse clinical outcomes.

Early versus delayed percutaneous coronary intervention in patients with non-ST elevation acute coronary syndromes

BackgroundThe optimal timing of angiography and percutaneous coronary intervention (PCI) in patients with non-ST elevation acute coronary syndromes (NSTEACS) remains uncertain. We sought to assess clinical characteristics and outcomes of patients in real-world contemporary practice who have early versus delayed PCI for NSTEACS. MethodsWe analyzed baseline clinical and procedural characteristics of 4307 patients with NSTEACS who underwent PCI from the Melbourne Interventional Group registry. Patients were assigned to the early PCI group if intervention was performed within a calendar day of presentation. The delayed PCI group received an intervention after one calendar day, but within the index admission. We assessed 30 days and 12-month mortality, myocardial infarction, target vessel revascularization, and major adverse cardiovascular events. The safety endpoint was in-hospital bleeding. ResultsOf the 4307 patients, 2210 (51%) received early PCI. The delayed PCI group were older (67±12 vs. 64±12, P<0.01), more likely to have biomarker elevation (70 vs. 66%, P<0.01), and had more comorbidities. There was no difference in efficacy at 30 days between the groups. At 12 months, delayed PCI was associated with higher mortality (4.6 vs. 3.3%, P=0.02), myocardial infarction (7.9 vs. 5.2%, P<0.01), and MACE (15.5 vs. 12.4%, P<0.01). On multivariate analysis, delayed PCI was not associated with increased mortality at 12 months (odds ratio 0.95, 95% confidence interval 0.7–1.3). ConclusionIn patients with stable NSTEACS treated with PCI, delayed intervention was performed in those who were older and had higher risk features. However, there appears to be no mortality hazard for these high-risk patients where PCI is delayed beyond the first 24 h after presentation and performed within the index admission.

Pretreatment with dual antiplatelet therapy in patients with ST‐elevation myocardial infarction

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.

Utility of the ACC/AHA lesion classification as a predictor of procedural, 30‐day and 12‐month outcomes in the contemporary percutaneous coronary intervention era

Correlations between the ACC/AHA coronary lesion classification and clinical outcomes in the contemporary percutaneous coronary intervention (PCI) era are not well established.