Consideration of QRS complex in addition to ST segment abnormalities in the estimation of the 'risk region' during acute inferior myocardial infarction.

BACKGROUND: The myocardial area at risk (MaR) has been estimated in patients with acute myocardial infarction (AMI) by using ST segment based ECG methods. However, as the process from ischemia to infarction progresses, the ST segment deviation is typically replaced by QRS abnormalities, causing a falsely low estimation of the total MaR if determined by using ST segment based methods. A previous study showed the value of the consideration of the abnormalities in the QRS complex, in addition to those in the ST segment estimating the total MaR for patients with anterior AMI. The purpose of this study was to investigate the same method for patients with inferior AMI. METHODS: Thirty-two patients with acute inferior ST elevation myocardial infarction received (99m)Tc-Sestamibi before percutaneous coronary intervention. SPECT was performed within 2 hours after treatment and was used as a gold standard for the estimation of the total MaR. The ECG recorded at admission in the hospital was used for the ECG estimates of the total MaR. This included a ST segment estimation of the ischemic component of the total MaR (Aldrich score) and an estimation of the infarcted component of the total MaR in the acute phase of AMI by QRS abnormalities (Selvester score). These scores were added for the combined ECG score. RESULTS: The ischemic component of the total MaR estimated by the Aldrich score alone no statistically significant correlation with SPECT (r=0.17, p=0.36). The infarcted component of the total MaR estimated by the Selvester score showed a significant correlation with SPECT (r=0.55, p=0.001). When the Aldrich and Selvester scores were combined, the correlation with SPECT improved (r=0.58, p<0.001). Both the Aldrich and Selvester score alone underestimated the mean MaR measured by SPECT (respectively p=0.007 and p<0.0001). There was no statistically significant difference between the mean MaR estimated by the sum of Aldrich and Selvester and the MaR measured by SPECT (p=0.636). CONCLUSION: The estimation of the total MaR was more accurate by taking both ST deviation and QRS abnormalities in account than by using either method alone. A new ECG method to determine the total MaR during acute coronary occlusion should consider both its ischemic and infarcted components.

Remote ischaemic conditioning before hospital admission, as a complement to angioplasty, and effect on myocardial salvage in patients with acute myocardial infarction: a randomised trial.

BACKGROUND: Remote ischaemic preconditioning attenuates cardiac injury at elective surgery and angioplasty. We tested the hypothesis that remote ischaemic conditioning during evolving ST-elevation myocardial infarction, and done before primary percutaneous coronary intervention, increases myocardial salvage. METHODS: 333 consecutive adult patients with a suspected first acute myocardial infarction were randomly assigned in a 1:1 ratio by computerised block randomisation to receive primary percutaneous coronary intervention with (n=166 patients) versus without (n=167) remote conditioning (intermittent arm ischaemia through four cycles of 5-min inflation and 5-min deflation of a blood-pressure cuff). Allocation was concealed with opaque sealed envelopes. Patients received remote conditioning during transport to hospital, and primary percutaneous coronary intervention in hospital. The primary endpoint was myocardial salvage index at 30 days after primary percutaneous coronary intervention, measured by myocardial perfusion imaging as the proportion of the area at risk salvaged by treatment; analysis was per protocol. This study is registered with ClinicalTrials.gov, number NCT00435266. FINDINGS: 82 patients were excluded on arrival at hospital because they did not meet inclusion criteria, 32 were lost to follow-up, and 77 did not complete the follow-up with data for salvage index. Median salvage index was 0.75 (IQR 0.50-0.93, n=73) in the remote conditioning group versus 0.55 (0.35-0.88, n=69) in the control group, with median difference of 0.10 (95% CI 0.01-0.22; p=0.0333); mean salvage index was 0.69 (SD 0.27) versus 0.57 (0.26), with mean difference of 0.12 (95% CI 0.01-0.21; p=0.0333). Major adverse coronary events were death (n=3 per group), reinfarction (n=1 per group), and heart failure (n=3 per group). INTERPRETATION: Remote ischaemic conditioning before hospital admission increases myocardial salvage, and has a favourable safety profile. Our findings merit a larger trial to establish the effect of remote conditioning on clinical outcomes. FUNDING: Fondation Leducq.

Consideration of QRS complex in addition to ST-segment abnormalities in the estimated "risk region" during acute anterior myocardial infarction.

BACKGROUND: The myocardial area at risk (MaR) has been estimated in patients with acute myocardial infarction (AMI) by using ST segment-based electrocardiographic (ECG) methods. As the process from ischemia to infarction progresses, the ST-segment deviation is typically replaced by QRS abnormalities causing a falsely low estimated total MaR if determined by using ST segment-based methods. The purpose of this study was to investigate if consideration of the abnormalities in the QRS complex, in addition to those in the ST segment, provides a more accurate estimated total MaR during anterior AMI than by considering the ST segment alone. METHODS: Twenty-five patients with acute anterior ST elevation myocardial infarction (STEMI) received technetium Tc 99m-sestamibi before percutaneous coronary intervention. Single photon emission computed tomography (SPECT) was performed within 2 hours after treatment and was used as a criterion standard for the estimated total MaR. The ECG recorded at admission in the hospital was used for the ECG estimated total MaR. This included an ST-segment estimated ischemic component of the total MaR (Aldrich score) and an estimated infarcted component of the total MaR in the acute phase of AMI by QRS abnormalities (Selvester score). These scores were added for the combined ECG score. RESULTS: The ischemic component of the total MaR estimated by the Aldrich score alone had no statistically significant correlation with SPECT (r = 0.21, P = .32). The infarcted component of the total MaR estimated by the Selvester score showed a significant correlation with SPECT (r = 0.49, P = .01). Each score gave a significant underestimated total MaR measured by SPECT (P < .01). When the Aldrich and Selvester scores were combined, the correlation with SPECT was r = 0.47, P = .02. The combined score still underestimated the total MaR by SPECT (P < .01), though the difference was smaller in comparison to either method alone (P < .01). CONCLUSION: The ECG estimated total MaR was more accurate by taking both ST deviation and QRS abnormalities into account than by using either method alone. A new ECG method to determine the total MaR during acute coronary occlusion should consider both its ischemic and infarcted components.

The ST injury vector: electrocardiogram-based estimation of location and extent of myocardial ischemia.

BACKGROUND: Analysis of ST deviations from the 12-lead electrocardiogram allows for estimation of a spatial ST injury vector. The goal of the present study was to compare the location and extent of transmural myocardial ischemia evaluated by myocardial perfusion imaging with the direction and magnitude of the ST injury vector. METHODS: Twelve-lead electrocardiograms were recorded from 75 acute myocardial infarction patients with single-vessel disease and thrombolysis in myocardial infarction (TIMI) flow 0/1 (30 left anterior descending [LAD], 28 right coronary artery [RCA], 17 left circumflex artery [LCX]). ST deviations were measured in the J point in all leads and used to estimate ST injury vectors for each patient. Myocardial perfusion imaging was performed to evaluate the extent and location of myocardial ischemia at the time of coronary intervention. RESULTS: Ninety-two percent of the patients showed ST injury vectors within the expected directional range for the identified anatomic segment of ischemia by myocardial perfusion imaging. ST injury vector direction separated LAD, RCA, and LCX occlusion patients; 90% of the LAD patients showed anterior vectors, 82% of the RCA patients showed posteroinferoseptal vectors, and 59% of the LCX patients showed posteroinferolateral vectors. Eight patients did not fulfill the ST elevation criteria for ST elevation myocardial infarction but showed anterior ST depression and prominent ST injury vectors in the posterior torso direction. There was a moderate correlation between the extent of ischemia and ST injury vector magnitude for the ischemic patients, r = 0.29. CONCLUSION: We found strong agreement between the direction of the ST injury vector and the location of myocardial ischemia. The ST injury vector may be the key to higher diagnostic accuracy for inferobasal transmural ischemia and may help distinguishing between RCA and LCX occlusions in the acute phase.

FFR Derived From Coronary CT Angiography in Nonculprit Lesions of Patients With Recent STEMI.

OBJECTIVES: This study sought to determine the diagnostic performance of noninvasive fractional flow reserve (FFR) derived from coronary computed tomography angiography (CTA) (FFRCT) for the diagnosis of lesion-specific ischemia in nonculprit vessels of patients with recent in ST-segment elevation myocardial infarction (STEMI). BACKGROUND: In patients with stable angina, FFRCT has high diagnostic performance in identification of ischemia-causing lesions. The potential value of FFRCT for assessment of multivessel disease in patients with recent STEMI has not been evaluated. METHODS: Coronary CTA with calculation of FFRCT and invasive coronary angiography with FFR were performed 1 month after STEMI in patients with multivessel disease. Coronary CTA and invasive coronary angiography stenosis >50% were considered obstructive. Lesion-specific ischemia was assumed if FFRCT was ≤0.80. FFR ≤0.80 was the reference standard. To evaluate the influence of vessel size, the total coronary vessel lumen volume relative to left ventricular mass (volume-to-mass ratio) was calculated and compared with that of patients with stable angina. RESULTS: The study evaluated 124 nonculprit vessels from 60 patients. Accuracy, sensitivity, and specificity of FFRCT were 72%, 83%, and 66% versus 64% (p = 0.033), 93% (p = 0.15), and 49% (p < 0.001) for CTA and 72% (p = 1.00), 76% (p = 0.46), and 70% (p = 0.54) for invasive coronary angiography. Following STEMI, median volume-to-mass ratio was lower than in patients with stable angina, 53 versus 65 mm3/g (p = 0.009). In patients with volume-to-mass ratio ≥65 mm3/g (upper tertile) accuracy, sensitivity, and specificity of FFRCT were all 83% versus 56% (p = 0.009), 75% (p = 0.61), and 44% (p = 0.003) in patients with <49 mm3/g (lower tertile). CONCLUSIONS: The diagnostic performance of FFRCT for staged detection of ischemia in STEMI patients with multivessel disease is moderate. STEMI patients have a smaller vessel volume than do patients with stable angina. The diagnostic performance of FFRCT is influenced by the volume-to-mass ratio. This study does not support routine use of FFRCT in the post-STEMI setting. (Assessment of Coronary Stenoses Using Coronary CT-Angiography and Noninvasive Fractional Flow Reserve; NCT01739075).

Quality of cardiopulmonary resuscitation in out-of-hospital cardiac arrest before and after introduction of a mechanical chest compression device, LUCAS-2; a prospective, observational study.

BACKGROUND: Mechanical chest compressions have been proposed to provide high-quality cardiopulmonary resuscitation (CPR), but despite the growing use of mechanical chest compression devices, only few studies have addressed their impact on CPR quality. This study aims to evaluate mechanical chest compressions provided by LUCAS-2 (Lund University Cardiac Assist System) compared with manual chest compression in a cohort of out-of-hospital cardiac arrest (OHCA) cases. METHODS: In this prospective study conducted in the Central Denmark Region, Denmark, the emergency medical service attempted resuscitation and reported data on 696 non-traumatic OHCA patients between April 2011 and February 2013. Of these, 155 were treated with LUCAS CPR after an episode with manual CPR. The CPR quality was evaluated using transthoracic impedance measurements collected from the LIFEPAK 12 defibrillator, and the effect was assessed in terms of chest compression rate, no-flow time and no-flow fraction; the fraction of time during resuscitation in which the patient is without spontaneous circulation receiving no chest compression. RESULTS: The median total episode duration was 21 minutes, and the episode with LUCAS CPR was significantly longer than the manual CPR episode, 13 minutes vs. 5 minutes, p < 0.001. The no-flow fraction was significantly lower during LUCAS CPR (16%) than during manual CPR (35%); difference 19% (95% CI: 16% to 21%; p < 0.001). No differences were found in pre- and post-shock no-flow time throughout manual CPR and LUCAS CPR. Contrary to the manual CPR, the average compression rate during LUCAS CPR was in conformity with the current Guidelines for Resuscitation, 102/minute vs. 124/minute, p < 0.001. CONCLUSION: Mechanical chest compressions provided by the LUCAS device improve CPR quality by significantly reducing the NFF and by improving the quality of chest compression compared with manual CPR during OHCA resuscitation. However, data on end-tidal Co2 and chest compression depth surrogate parameters of CPR quality could not be reported.

Feasibility and early safety of hybrid coronary revascularisation combining off-pump coronary surgery through J-hemisternotomy with percutaneous coronary intervention.

AIMS: To assess the procedural feasibility and early safety of hybrid coronary revascularisation, combining off-pump left internal mammary artery grafting to the left descending coronary artery (LAD) through an inferior J-hemisternotomy (JOPCAB) with percutaneous coronary intervention (PCI) of non-LAD lesions. METHODS AND RESULTS: A total of 100 patients with multivessel coronary artery disease involving LAD were included in this prospective registry. Hybrid revascularisation was performed by JOPCAB, either prior to PCI (89%) or following PCI (11%). In 96% of the cases, the procedure was carried out according to the preoperative strategy and without perioperative (24 hours) major adverse cardiac or cerebral events. At one month, we observed no deaths, one stroke and two procedure-related myocardial infarctions. Five patients underwent reoperation for graft dysfunction, four of whom were identified by angiography without prior signs of ischaemia. Reoperation due to bleeding was necessary in six patients, and nine patients received red blood cell transfusion. CONCLUSIONS: Our prospective registry documented promising procedural feasibility and early safety of coronary hybrid revascularisation combining JOPCAB with PCI. ClinicalTrials.gov identifier: NCT01496664.

24-hour antiplatelet effect of aspirin in patients with previous definite stent thrombosis.

OBJECTIVE: Once-daily aspirin is standard treatment, but recent studies point towards increased platelet function at the end of the dosing interval. Stent thrombosis (ST) has been linked with reduced antiplatelet effect of aspirin, so we investigated if platelet inhibition by aspirin declines through 24 h in patients with previous definite ST. Furthermore, we explored whether increased levels of immature platelets and thrombopoietin are associated with a particularly rapid recovery of platelet function. METHODS: This case-control study included 50 patients with previous definite ST matched with 100 patients with stable coronary artery disease and 50 healthy volunteers. All participants were on aspirin 75 mg/day mono antiplatelet therapy. Platelet aggregation was measured 1 and 24 h after aspirin intake using platelet aggregometry (Multiplate® Analyzer). Cyclooxygenase-1 activity, platelet activation, immature platelets, and thrombopoietin were measured. RESULTS: Platelet aggregation increased by 109±150 (arachidonic acid) and 47±155 (collagen) aggregation units per minute from 1 to 24 h after aspirin intake (p-values <0.0001) with corresponding increases in thromboxane B2 (5.6±5.1 ng/ml, p<0.0001) and soluble P-selectin (6.2±15.5 ng/ml, p<0.0001). Platelet aggregation increased equally in all groups, but patients with previous ST displayed the highest levels of platelet aggregation at 24 h (p-values≤0.05) and the highest levels of immature platelets (p<0.01) and thrombopoietin (p<0.0001). CONCLUSIONS: Platelet inhibition declined significantly during the 24-hour dosing interval in aspirin-treated patients with previous definite ST or stable coronary artery disease and in healthy individuals. Increased levels of immature platelets and thrombopoietin were observed in patients with previous definite ST.

Fractional flow reserve derived from coronary CT angiography: variation of repeated analyses.

BACKGROUND: Fractional flow reserve (FFR) is the standard of reference for assessing the hemodynamic significance of coronary stenoses in patients with stable coronary artery disease. Noninvasive FFR derived from coronary CT angiography (FFRCT) is a promising new noninvasive method for assessing the physiologic significance of epicardial stenoses. The reproducibility of FFRCT has not yet been established. OBJECTIVE: The aim of this study was to evaluate the variation of repeated analyses of FFRCT per se and in the context of the reproducibility of repeated FFR measurements. METHODS: Coronary CT angiography and invasive coronary angiography with repeated FFR measurements were performed in 28 patients (58 vessels) with suspected stable coronary artery disease. Based on the coronary CT angiography data set, FFRCT analyses were performed twice by 2 independent blinded analysts. RESULTS: In 12 of 58 (21%) vessels FFR was ≤ 0.80. The standard deviation for the difference between first and second FFRCT analyses was 0.034 vs 0.033 for FFR repeated measurements (P = .722). Limits of agreement were -0.06 to 0.08 for FFRCT and -0.07 to 0.06 for FFR. The coefficient of variation of FFRCT (CVFFRct) was 3.4% (95% confidence interval [CI], 1.4%-4.6%) vs 2.7% (95% CI, 1.8%-3.3%) for FFR. In vessels with mean FFR ranging between 0.70 and 0.90 (n = 25), the difference between the first and second FFRCT analyses was 0.035 and FFR repeated measurements was 0.043 (P = .357), whereas CVFFRct was 3.3% (95% CI, 1.5%-4.3%) and coefficient of variation for FFR was 3.6% (95% CI, 2.3%-4.6%). CONCLUSIONS: The reproducibility of both repeated FFRCT analyses and repeated FFR measurements is high.

Patients with previous definite stent thrombosis have a reduced antiplatelet effect of aspirin and a larger fraction of immature platelets.

OBJECTIVES: This study sought to evaluate the platelet response to aspirin and the immature platelet fraction in patients with previous stent thrombosis (ST). BACKGROUND: ST is a potentially fatal complication of coronary stenting. A reduced platelet response to aspirin increases the risk of cardiovascular events. METHODS: We included 117 patients previously undergoing percutaneous coronary intervention. A total of 39 patients had suffered ST and 78 patients served as controls matched at a 1:2 ratio with respect to age, sex, stent type, and percutaneous coronary intervention indication. All patients were treated with aspirin 75 mg once daily. Platelet function was assessed by multiple electrode aggregometry in citrated and hirudinized blood and by VerifyNow Aspirin Assay (Accumetrics, San Diego, California). Flow cytometric determination of the immature platelet fraction was performed to evaluate platelet turnover. Platelet activation was evaluated by soluble serum P-selectin. Compliance was confirmed by serum thromboxane B(2). RESULTS: All patients were fully compliant, which was confirmed by suppressed levels of serum thromboxane B(2). Platelet aggregation was increased in patients with previous ST when assessed by multiple electrode aggregometry induced by collagen (p(citrated blood) = 0.003; p(hirudinized blood) < 0.0001) and by arachidonic acid (p(citrated blood) = 0.16; p(hirudinized blood) = 0.04), respectively. Similarly, platelet aggregation assessed by VerifyNow was higher in ST cases (p = 0.12). A trend toward an increased immature platelet fraction among cases was seen (p = 0.13), whereas P-selectin levels (p = 0.56) did not differ between groups. CONCLUSIONS: Overall, patients with previous ST had a reduced antiplatelet effect of aspirin, which might be explained by an increased platelet turnover.