J. Chandrasekhar

Shorter Ischaemic Time and Improved Survival with Pre-hospital STEMI Diagnosis and Direct Transfer for Primary PCI

BACKGROUND We sought to determine if our regional program for pre-hospital STEMI diagnosis and direct transfer for primary PCI (PPCI) was associated with shorter ischaemic times and improved survival compared with ED diagnosis. METHODS STEMI diagnosis was made at the scene by pre-hospital ECG or in local EDs depending on patient presentation. Ambulance ECGs were transmitted to our ED for cath lab activation. Patient variables and outcomes at 12 months were recorded. RESULTS We treated 782 consecutive patients with PPCI during January 2008-June 2013. Cath lab activation was initiated prior to hospital arrival (pre-hospital) in 24% of cases and by ED in 76% of cases. Median total ischaemic time was 154 min for pre-hospital and 211 minutes for ED patients (p<0.0001). Mortality at 12 months was 7.9% in the ED group compared with 3.7% in the pre-hospital group (p=0.036). On multivariate Cox regression analysis including baseline and procedural variables, pre-hospital activation remained an independent predictor of mortality (HR 0.45, 95% CI 0.20-1.0, p=0.03). CONCLUSIONS Pre-hospital diagnosis of STEMI and direct transfer to the cath lab reduced total ischaemic time by 57 minutes and mortality by >50% following PPCI. Further efforts are needed to increase the proportion of STEMI patients treated using this strategy.

Benefits of dual-axis rotational coronary angiography in routine clinical practice

Dual-axis rotational coronary angiography (DARCA) is a new imaging technique involving three-dimensional rotation of the gantry around the patient with simultaneous left to right and craniocaudal movements. This allows complete imaging of the left or right coronary tree with a single acquisition run. Previous small studies have indicated that DARCA is associated with reduced radiation dose and contrast use in comparison with standard coronary angiography (SCA). We conducted a registry of unselected patients undergoing DARCA or SCA. DARCA was used in 107 patients and SCA in 105 patients. Mean number of acquisition runs was 2.6 for DARCA and 6.9 for SCA (P < 0.0001). Mean radiation dose (dose–area product, DAP) was 30.4 Gy cm2 for SCA and 15.9 Gy cm2 for DARCA (P < 0.0001). Mean contrast volume was 41.7 ml for SCA and 25.7 ml for DARCA (P < 0.0001). Case time for DARCA in the first half of the study was 20.8 ± 1.4 min compared with 15.2 ± 2.0 min in the second half of the study (P = 0.0015), suggesting a learning curve. In the DARCA group, 64 % of patients required only two acquisition runs for complete and satisfactory imaging. There were no adverse effects resulting from DARCA. Two cases are presented to illustrate the diagnostic ability of DARCA. DARCA was associated with a 48 % reduction in radiation dose and 36 % reduction in contrast volume in comparison with SCA, with comparable diagnostic ability.

Symptom-to-Balloon Time is a Strong Predictor of Adverse Events Following Primary Percutaneous Coronary Intervention: Results From the Australian Capital Territory PCI Registry

BACKGROUND Notwithstanding improvements in door-to-balloon time, adverse event rates after primary PCI have remained steady. We analysed the effect of symptom-to-balloon (STB) time, a reflection of total ischaemic time, on major adverse cardiovascular events (MACE) and explored predictors of prolonged STB time. METHODS The study population included 1002 consecutive patients (22.4% women) with a mean age of 62.3±13.2 years, who underwent primary PCI during 2008-2014. Groups were compared for STB ≤ and >240min. Primary endpoint was one-year MACE, a composite of death, reinfarction, stent thrombosis or target vessel revascularisation. RESULTS Symptom-to-balloon time was available in 893 patients of which 588 (65.8%) had STB ≤240min and 305 (34.2%) had STB >240min. The incidence of one-year MACE increased significantly in a stepwise manner with increasing STB time (p for trend=0.003). Symptom-to-balloon time was an independent predictor of one-year MACE along with age >70 years, final TIMI flow <3, three vessel disease, cardiogenic shock and out-of-hospital cardiac arrest. We also performed a multivariate analysis to determine predictors of delayed treatment. Predictors of STB time >240min were age >70 years, female gender, diabetes, absence of prehospital catheter laboratory activation and presentation to a non-PCI centre. CONCLUSION Incidence of MACE was strongly correlated with STB time and STB time was an independent predictor of MACE. We have identified specific subgroups with prolonged STB times (age >70, female gender, diabetes, absence of prehospital activation and presentation to a non-PCI centre). This information should inform future studies and strategies to minimise delays in these subgroups for improved outcomes.

Efficacy of non-compliant balloon post-dilation in optimization of contemporary stents: A digital stent enhancement study

Background There is no evidence from randomized trials for the benefit of routine non-compliant balloon (NCB) post-dilation after stent deployment. Despite being the gold standard, intravascular ultrasound is infrequently performed due to time and cost constraints and a suitable alternative technology is required for routine assessment of stent expansion. The purpose of this study was to assess the contribution of NCB post-dilation in optimizing contemporary stents by using digital stent enhancement (DSE). Methods We treated 120 patients with stent insertion and assessed the stents with DSE before and after NCB use. Optimal expansion was defined as the minimum stent diameter (MSD) ≥ 90% of the nominal stent diameter, an adaptation of the MUSIC and POSTIT trial criteria. Stent deployment was performed at 12 atm pressure followed by routine NCB post-dilation at ≥ 14 atm. Results The mean reference diameter on QCA was 2.75 mm (SD 0.63) and mean stent diameter was 3.15 mm (SD 0.46). At a mean stent deployment pressure of 11.7 atm (SD 2.4), only 21% of stents were optimally expanded. After NCB inflation at a mean of 16.9 atm (SD 2.8), MSD increased by 0.26 mm (SD 0.24), optimal stent expansion increased from 21% to 58% and mean stent symmetry ratio increased from 0.83 to 0.87 (p < 0.0001). Conclusions Contemporary stents are sub-optimally expanded in the majority of cases after standard deployment compared with nominal sizes. Adjunctive NCB post-dilation optimized an additional 37% of stents. DSE analysis can assist in qualitative and quantitative stent assessments and can potentially facilitate a selective NCB post-dilation strategy to achieve optimal stent expansion.