Serial fractional flow reserve, coronary flow reserve and index of microcirculatory resistance after percutaneous coronary intervention in patients treated for stable angina pectoris assessed with PET.

BACKGROUND: Cardiac 15 O-water PET is a noninvasive method to evaluate epicardial and microvascular dysfunction and further quantitate absolute myocardial blood flow (MBF). AIM: The aim of this study was to assess the impact of revascularization on MBF and myocardial flow reserve (MFR) assessed with 15 O-water PET and invasive flow and pressure measurements. METHODS: In 21 patients with single-vessel disease referred for percutaneous coronary intervention (PCI), serial PET perfusion imaging and fractional flow reserve (FFR), coronary flow reserve (CFR) and index of microcirculatory resistance (IMR) were performed during PCI and after 3 months. RESULTS: In the affected myocardium, stress MBF and MFR increased significantly from before revascularization to 3 months after revascularization: stress MBF 2.4 ±â€…0.8 vs. 3.2 ±â€…0.8; P  < 0.001 and MFR 2.5 ±â€…0.8 vs. 3.4 ±â€…1.1; P  = 0.004. FFR and CFR increased significantly from baseline to after revascularization and remained stable from after revascularization to 3-month follow-up: FFR 0.64 ±â€…0.20 vs. 0.91 ±â€…0.06 vs. 0.91 ±â€…0.07; P  < 0.001; CFR 2.4 ±â€…1.2 vs. 3.6 ±â€…1.9 vs. 3.6 ±â€…1.9; P  < 0.001, whereas IMR did not change significantly: 30.3 ±â€…22.9 vs. 30.1 ±â€…25.3 vs. 31.9 ±â€…25.2; P  = ns. After revascularization, an increase in stress MBF was associated with an increase in FFR ( r  = 0.732; P  < 0.001) and an increase in MFR ( r  = 0.499; P  = 0.021). IMR measured before PCI was inversely associated with improvement in stress MBF, ( r  = -0.616; P  = 0.004). CONCLUSION: Recovery of myocardial perfusion after PCI was associated with an increase in FFR 3 months after revascularization. Microcirculatory dysfunction was associated with less improvement in myocardial perfusion.

15O-Water Positron Emission Tomography of Myocardial Ischemia in Patients Referred for Percutaneous Coronary Intervention.

The diagnostic accuracy of non-invasive diagnostic methods for detecting coronary artery disease has increased in recent years. This study aimed to assess the diagnostic performance of 15O-water positron emission tomography (PET) in terms of stress myocardial blood flow (MBF) and myocardial flow reserve (MFR) in patients with single-vessel disease referred for percutaneous coronary intervention (PCI), using fractional flow reserve (FFR) value of ≤0.80 as the reference for a significant stenosis. We also assessed the influence of the index of microcirculatory resistance (IMR) on the diagnostic performance of PET. 15O-water PET FFR and IMR were measured before PCI in 26 patients with single-vessel disease. Stress MBF < 2.5 ml/min/g (95% confidence interval [CI]) had sensitivity 78% (95% CI: 52%-94%), specificity 50% (95% CI: 16%-84%), positive predictive value (PPV) 78% (95% CI: 63%-88%), negative predictive value (NPV) 50% (95% CI: 25%-75%), and accuracy 69% (95% CI: 48%-86%). MFR < 2.5 had sensitivity 72% (95% CI: 47%-90%), specificity 75% (95% CI: 35%-97%), PPV 87% (95% CI: 65%-96%), NPV 55% (95% CI: 34%-74%), and accuracy 73% (95% CI: 52%-88%). In patients with IMR > 24, stress MBF correlated with FFR (r = 0.651; p = 0.016) whereas stress MBF did not correlate with FFR in patients with IMR < 24. In conclusion, stress MBF and MFR had modest diagnostic performance compared to invasive FFR measurements in patients with single-vessel disease.

One-year rehospitalisation after percutaneous coronary intervention: a retrospective analysis.

AIMS: The aim of the study was to evaluate the incidence and causes of rehospitalisation within one year after percutaneous coronary intervention (PCI) in a country where the National Health Service provides universal tax-supported healthcare, guaranteeing residents free hospital access. METHODS AND RESULTS: Between January 2010 and September 2014, 17,111 patients were treated with PCI in two University Hospitals in Western Denmark. Patients who were readmitted within one year after PCI were identified. The overall one-year readmission rate was 50.4%. The cause was angina/myocardial infarction (MI) in 4,282 patients (49.7%), and other reasons in 4,334 (50.3%). Predictors of angina/MI-related readmissions were female gender (odds ratio [OR] 1.15, 95% confidence interval [CI]: 1.07-1.25), diabetes (OR 1.14, 95% CI: 1.04-1.26), age (per 10-year increase) (OR 0.86, 95% CI: 0.83-0.88), and indication for index PCI (stable angina pectoris as reference): ST-segment elevation myocardial infarction (OR 1.34, 95% CI: 1.23-1.47) and non-ST-segment elevation myocardial infarction (OR 1.18, 95% CI: 1.08-1.29). Predictors for other readmissions were female gender (OR 1.09, 95% CI: 1.01-1.18), diabetes (OR 1.29, 95% CI: 1.18-1.42), age (OR 1.30, 95% CI: 1.26-1.34) and Charlson comorbidity index ≥3 (OR 3.03, 95% CI: 2.71-3.27). CONCLUSIONS: In an unselected patient cohort treated with PCI, half of the patients were rehospitalised within one year, highlighting the impact of comorbidity in patients with ischaemic heart disease.

The Stop-Only-While-Shocking algorithm reduces hands-off time by 17% during cardiopulmonary resuscitation - a simulation study.

INTRODUCTION: Reducing hands-off time during cardiopulmonary resuscitation (CPR) is believed to increase survival after cardiac arrests because of the sustaining of organ perfusion. The aim of our study was to investigate whether charging the defibrillator before rhythm analyses and shock delivery significantly reduced hands-off time compared with the European Resuscitation Council (ERC) 2010 CPR guideline algorithm in full-scale cardiac arrest scenarios. METHODS: The study was designed as a full-scale cardiac arrest simulation study including administration of drugs. Participants were randomized into using the Stop-Only-While-Shocking (SOWS) algorithm or the ERC2010 algorithm. In SOWS, chest compressions were only interrupted for a post-charging rhythm analysis and immediate shock delivery. A Resusci Anne HLR-D manikin and a LIFEPACK 20 defibrillator were used. The manikin recorded time and chest compressions. RESULTS: Sample size was calculated with an α of 0.05 and 80% power showed that we should test four scenarios with each algorithm. Twenty-nine physicians participated in 11 scenarios. Hands-off time was significantly reduced 17% using the SOWS algorithm compared with ERC2010 [22.1% (SD 2.3) hands-off time vs. 26.6% (SD 4.8); P<0.05]. CONCLUSION: In full-scale cardiac arrest simulations, a minor change consisting of charging the defibrillator before rhythm check reduces hands-off time by 17% compared with ERC2010 guidelines.

Reduction of treatment delay in patients with ST-elevation myocardial infarction: impact of pre-hospital diagnosis and direct referral to primary percutanous coronary intervention.

AIMS: The majority of patients with ST-elevation myocardial infarction (STEMI) are admitted to local hospitals without primary percutaneous coronary intervention (primary PCI) facilities. Acute transferral to an interventional centre is necessary to treat these patients with primary PCI. The present study assessed the reduction in treatment delay achieved by pre-hospital diagnosis and referral directly to an interventional centre. METHODS AND RESULTS: Two local hospitals without primary PCI facilities were serving the study region. Pre-hospital diagnoses were established with the use of telemedicine, by ambulance physicians, or by general practitioners. Primary PCI was accepted as the preferred reperfusion therapy in patients with STEMI. From 31 October 2002 to 31 January 2004 all patients transported by ambulance and transferred for primary PCI were registered. Patients with STEMI were divided into three groups: (A) patients diagnosed at a local hospital (n = 55), (B) patients diagnosed pre-hospitally and admitted to a local hospital (n = 85), and (C) patients diagnosed pre-hospitally and referred directly to the interventional centre (n = 21). When comparing group A with group B and C, no difference was found in age, sex, infarct location, or distance from the scene of event to the interventional centre, whereas the median time from ambulance call to first balloon inflation was 41 min shorter in group B compared with group A (P<0.001) and 81 min shorter in group C compared with group A (P<0.001). CONCLUSION: In a cohort of patients scheduled for admission to a local hospital and subsequent transferral to an interventional centre for primary PCI, those diagnosed pre-hospitally had shorter treatment delay compared with those diagnosed in hospital, both in the setting of initial admission to a local hospital, and to an even larger extent in the setting of referral directly to the interventional centre.