Culprit lesion plaque characterization and thrombus grading by high-definition intravascular ultrasound in patients with ST-segment elevation myocardial infarction.

BACKGROUND: Dedicated prospective studies investigating high-definition intravascular ultrasound (HD-IVUS)-guided primary percutaneous coronary intervention (PCI) are lacking. The aim of this study was to qualify and quantify culprit lesion plaque characteristics and thrombus using HD-IVUS in patients presenting with ST-segment elevation myocardial infarction (STEMI). METHODS: The SPECTRUM study is a prospective, single-center, observational cohort study investigating the impact of HD-IVUS-guided primary PCI in 200 STEMI patients (NCT05007535). The first 100 study patients with a de novo culprit lesion and a per-protocol mandated preintervention pullback directly after vessel wiring were subject to a predefined imaging analysis. Culprit lesion plaque characteristics and different thrombus types were assessed. An IVUS-derived thrombus score, including a 1-point adjudication for a long total thrombus length, long occlusive thrombus length, and large maximum thrombus angle, was developed to differentiate between low (0-1 points) and high (2-3 points) thrombus burden. Optimal cut-off values were obtained using receiver operating characteristic curves. RESULTS: The mean age was 63.5 (±12.1) years and 69 (69.0%) patients were male. The median culprit lesion length was 33.5 (22.8-38.9) mm. Plaque rupture and convex calcium were appreciated in 48 (48.0%) and 10 (10.0%) patients, respectively. Thrombus was observed in 91 (91.0%) patients (acute thrombus 3.3%; subacute thrombus 100.0%; organized thrombus 22.0%). High IVUS-derived thrombus burden was present in 37/91 (40.7%) patients and was associated with higher rates of impaired final thrombolysis in myocardial infarction flow (grade 0-2) (27.0% vs. 1.9%, p < 0.001). CONCLUSIONS: HD-IVUS in patients presenting with STEMI allows detailed culprit lesion plaque characterization and thrombus grading that may guide tailored PCI.

International External Validation Study of the 2014 European Society of Cardiology Guidelines on Sudden Cardiac Death Prevention in Hypertrophic Cardiomyopathy (EVIDENCE-HCM).

BACKGROUND: Identification of people with hypertrophic cardiomyopathy (HCM) who are at risk of sudden cardiac death (SCD) and require a prophylactic implantable cardioverter defibrillator is challenging. In 2014, the European Society of Cardiology proposed a new risk stratification method based on a risk prediction model (HCM Risk-SCD) that estimates the 5-year risk of SCD. The aim was to externally validate the 2014 European Society of Cardiology recommendations in a geographically diverse cohort of patients recruited from the United States, Europe, the Middle East, and Asia. METHODS: This was an observational, retrospective, longitudinal cohort study. RESULTS: The cohort consisted of 3703 patients. Seventy three (2%) patients reached the SCD end point within 5 years of follow-up (5-year incidence, 2.4% [95% confidence interval {CI}, 1.9-3.0]). The validation study revealed a calibration slope of 1.02 (95% CI, 0.93-1.12), C-index of 0.70 (95% CI, 0.68-0.72), and D-statistic of 1.17 (95% CI, 1.05-1.29). In a complete case analysis (n= 2147; 44 SCD end points at 5 years), patients with a predicted 5-year risk of <4% (n=1524; 71%) had an observed 5-year SCD incidence of 1.4% (95% CI, 0.8-2.2); patients with a predicted risk of ≥6% (n=297; 14%) had an observed SCD incidence of 8.9% (95% CI, 5.96-13.1) at 5 years. For every 13 (297/23) implantable cardioverter defibrillator implantations in patients with an estimated 5-year SCD risk ≥6%, 1 patient can potentially be saved from SCD. CONCLUSIONS: This study confirms that the HCM Risk-SCD model provides accurate prognostic information that can be used to target implantable cardioverter defibrillator therapy in patients at the highest risk of SCD.

Clinical impact of direct stenting and interaction with thrombus aspiration in patients with ST-segment elevation myocardial infarction undergoing percutaneous coronary intervention: Thrombectomy Trialists Collaboration.

Aims: Preliminary studies suggest that direct stenting (DS) during percutaneous coronary intervention (PCI) may reduce microvascular obstruction and improve clinical outcome. Thrombus aspiration may facilitate DS. We assessed the impact of DS on clinical outcome and myocardial reperfusion and its interaction with thrombus aspiration among ST-segment elevation myocardial infarction (STEMI) patients undergoing PCI. Methods and results: Patient-level data from the three largest randomized trials on routine manual thrombus aspiration vs. PCI only were merged. A 1:1 propensity matched population was created to compare DS and conventional stenting. Synergy between DS and thrombus aspiration was assessed with interaction P-values in the final models. In the unmatched population (n = 17 329), 32% underwent DS and 68% underwent conventional stenting. Direct stenting rates were higher in patients randomized to thrombus aspiration as compared with PCI only (41% vs. 22%; P < 0.001). Patients undergoing DS required less contrast (162 mL vs. 172 mL; P < 0.001) and had shorter fluoroscopy time (11.1 min vs. 13.3 min; P < 0.001). After propensity matching (n = 10 944), no significant differences were seen between DS and conventional stenting with respect to 30-day cardiovascular death [1.7% vs. 1.9%; hazard ratio 0.88, 95% confidence interval (CI) 0.55-1.41; P = 0.60; Pinteraction = 0.96) and 30-day stroke or transient ischaemic attack (0.6% vs. 0.4%; odds ratio 1.02; 95% CI 0.14-7.54; P = 0.99; Pinteraction = 0.81). One-year results were similar. No significant differences were seen in electrocardiographic and angiographic myocardial reperfusion measures. Conclusion: Direct stenting rates were higher in patients randomized to thrombus aspiration. Clinical outcomes and myocardial reperfusion measures did not differ significantly between DS and conventional stenting and there was no interaction with thrombus aspiration.

Thrombus Aspiration in ST-Segment-Elevation Myocardial Infarction: An Individual Patient Meta-Analysis: Thrombectomy Trialists Collaboration.

BACKGROUND: Thrombus aspiration during percutaneous coronary intervention (PCI) for the treatment of ST-segment-elevation myocardial infarction (STEMI) has been widely used; however, recent trials have questioned its value and safety. In this meta-analysis, we, the trial investigators, aimed to pool the individual patient data from these trials to determine the benefits and risks of thrombus aspiration during PCI in patients with ST-segment-elevation myocardial infarction. METHODS: Included were large (n≥1000), randomized, controlled trials comparing manual thrombectomy and PCI alone in patients with ST-segment-elevation myocardial infarction. Individual patient data were provided by the leadership of each trial. The prespecified primary efficacy outcome was cardiovascular mortality within 30 days, and the primary safety outcome was stroke or transient ischemic attack within 30 days. RESULTS: The 3 eligible randomized trials (TAPAS [Thrombus Aspiration During Percutaneous Coronary Intervention in Acute Myocardial Infarction], TASTE [Thrombus Aspiration in ST-Elevation Myocardial Infarction in Scandinavia], and TOTAL [Trial of Routine Aspiration Thrombectomy With PCI Versus PCI Alone in Patients With STEMI]) enrolled 19 047 patients, of whom 18 306 underwent PCI and were included in the primary analysis. Cardiovascular death at 30 days occurred in 221 of 9155 patients (2.4%) randomized to thrombus aspiration and 262 of 9151 (2.9%) randomized to PCI alone (hazard ratio, 0.84; 95% confidence interval, 0.70-1.01; P=0.06). Stroke or transient ischemic attack occurred in 66 (0.8%) randomized to thrombus aspiration and 46 (0.5%) randomized to PCI alone (odds ratio, 1.43; 95% confidence interval, 0.98-2.10; P=0.06). There were no significant differences in recurrent myocardial infarction, stent thrombosis, heart failure, or target vessel revascularization. In the subgroup with high thrombus burden (TIMI [Thrombolysis in Myocardial Infarction] thrombus grade ≥3), thrombus aspiration was associated with fewer cardiovascular deaths (170 [2.5%] versus 205 [3.1%]; hazard ratio, 0.80; 95% confidence interval, 0.65-0.98; P=0.03) and with more strokes or transient ischemic attacks (55 [0.9%] versus 34 [0.5%]; odds ratio, 1.56; 95% confidence interval, 1.02-2.42, P=0.04). However, the interaction P values were 0.32 and 0.34, respectively. CONCLUSIONS: Routine thrombus aspiration during PCI for ST-segment-elevation myocardial infarction did not improve clinical outcomes. In the high thrombus burden group, the trends toward reduced cardiovascular death and increased stroke or transient ischemic attack provide a rationale for future trials of improved thrombus aspiration technologies in this high-risk subgroup. CLINICAL TRIAL REGISTRATION: URLs: http://www.ClinicalTrials.gov http://www.crd.york.ac.uk/prospero/. Unique identifiers: NCT02552407 and CRD42015025936.

Acute Isolated Right Ventricular Infarction.

The electrocardiogram is universally used to diagnose ST-segment elevation myocardial infarction and serves as guidance for the interventional cardiologist to identify the acute thrombotic lesion. However, this case illustrates that the electrocardiogram can also be deceiving.

Association Between 3D-Angiography Based Fractional Flow Reserve and Non-Invasive Myocardial Ischemia Testing: The FAST ISCHEMIA Study.

BACKGROUND: In order to facilitate fractional flow reserve (FFR)-guided lesion assessment, several 3-dimensional (3D)-angiography-based physiological indices have been recently validated. Thus far, limited data are available on the association of these indices with conventional forms of ischemia testing. AIM: The aim of the study was to determine the association between 3D-angiography-based vessel-FFR (vFFR) and myocardial ischemia as assessed by exercise electrocardiography (ECG) testing, dobutamine stress echocardiography, single photon emission computed tomography myocardial perfusion imaging (SPECTMPI), and stress cardiovascular magnetic resonance imaging (stress CMR). METHODS: FAST ISCHEMIA is a retrospective, single-center cohort study including patients who underwent non-invasive myocardial ischemia testing and subsequent coronary angiography (≤3 months). A total of 145 patients (340 vessels) were analyzed. The overall patient-based sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), positive likelihood ratio (LR+), and negative likelihood ratio (LR-) of vFFR ≤0.80 in any vessel for ischemia was 64% (95% confidence interval [CI], 53-74), 71% (95% CI, 54-84), 83% (95% CI, 72-91), 46% (95% CI, 33-60), 2.16 (95% CI, 1.25-3.74), and 0.52 (95% CI, 0.36-0.74), respectively. Multivariable logistic regression showed that vFFR ≤0.80 was significantly associated with ischemia on a patient level (odds ratio, 8.13; 95% CI, 2.51-30.06; P<.001) and on a vascular territory level (odds ratio, 2.75; 95% CI, 1.17-6.44; P<.01). CONCLUSION: Our study suggests that vFFR ≤0.80 has a modest association with non-invasive myocardial ischemia testing using either exercise ECG or stress imaging modalities. After correcting for independent confounders, vFFR was independently associated with ischemia on a non-invasive myocardial ischemia detection test.

Sex-Related Differences in Thrombus Burden in STEMI Patients Undergoing Primary Percutaneous Coronary Intervention.

BACKGROUND: Women have a worse prognosis after ST-segment elevation myocardial infarction (STEMI) than men. The prognostic role of thrombus burden (TB) in influencing the sex-related differences in clinical outcomes after STEMI has not been clearly investigated. OBJECTIVES: The aim of this study was to assess the sex-related differences in TB and its clinical implications in patients with STEMI. METHODS: Individual patient data from the 3 major randomized clinical trials of manual thrombus aspiration were analyzed, encompassing a total of 19,047 patients with STEMI, of whom 13,885 (76.1%) were men and 4,371 (23.9%) were women. The primary outcome of interest was 1-year cardiovascular (CV) death. The secondary outcomes of interest were recurrent myocardial infarction, heart failure, all-cause mortality, stroke, stent thrombosis (ST), and target vessel revascularization at 1 year. RESULTS: Patients with high TB (HTB) had worse 1-year outcomes compared with those presenting with low TB (adjusted HR for CV death: 1.52; 95% CI: 1.10-2.12; P = 0.01). In unadjusted analyses, female sex was associated with an increased risk for 1-year CV death regardless of TB. After adjustment, the risk for 1-year CV death was higher only in women with HTB (HR: 1.23; 95% CI: 1.18-1.28; P < 0.001), who also had an increased risk for all-cause death and ST than men. CONCLUSIONS: In patients with STEMI, angiographic evidence of HTB negatively affected prognosis. Among patients with HTB, women had an excess risk for ST, CV, and all-cause mortality than men. Further investigations are warranted to better understand the pathophysiological mechanisms leading to excess mortality in women with STEMI and HTB.

Cardiac Catheterizations in Patients With Acute Coronary Syndrome and Prior Coronary Bypass Surgery: Impact of Native vs Graft vs Absent Culprit Lesions on Clinical Outcomes and Treatment Strategy.

BACKGROUND: In patients with prior coronary artery bypass graft surgery (CABG), acute coronary syndrome (ACS) is not uncommon. This study investigated treatment strategy and compared clinical outcomes for native, graft and absent culprit lesions. METHODS: Single-center retrospective cohort study. From July 2010 to July 2019, 642 consecutive ACS patients with prior CABG were screened for eligibility. The primary endpoint was major adverse cardiovascular events (MACE) at 1 year, a composite of all-cause mortality, myocardial infarction, stroke and ischemia-driven revascularization. RESULTS: A total of 549 patients were included, with 215 (39.2 %) having native culprits, 256 (46.6 %) graft culprits and 78 (14.2 %) no clear culprits. Patients with native culprits were treated with native PCI in 94.0 %, re-CABG in 0.9 % and optimal medical therapy (OMT) in 5.1 %. Patients with graft culprits were treated with native PCI in 14.1 %, graft PCI in 81.2 %, re-CABG in 0.8 % and OMT in 3.9 %. All patients without a clear culprit received OMT. The cumulative incidence of 1-year MACE was 24.7 % for native vs 26.2 % for graft vs 21.8 % for absent culprits. Kaplan-Meier curves did not differ significantly. In patients with graft culprit, no significant difference in 1-year MACE was observed between native PCI and graft PCI (30.6 % vs 25.5 %, p = 0.36). CONCLUSIONS: This retrospective study shows that in ACS patients with prior CABG, MACE occurred frequently and was comparable for native, graft and absent culprits. Native PCI as treatment strategy for patients with a graft culprit was relatively common, with no significant difference in MACE as compared to graft PCI.

Intravascular ultrasound-guided versus coronary angiography-guided percutaneous coronary intervention in patients with acute myocardial infarction: A systematic review and meta-analysis.

BACKGROUND: Intravascular ultrasound (IVUS) can overcome the intrinsic limitations of coronary angiography for lesion assessment and stenting. IVUS improves outcomes of patients presenting with stable or complex coronary artery disease, but dedicated data on the impact of IVUS-guided percutaneous coronary intervention (PCI) in patients with acute myocardial infarction (AMI) remains scarce. METHODS: We systematically searched Embase, MEDLINE, Web of Science Core Collection, Cochrane Central Register of Controlled Trials and Google Scholar for studies that compared clinical outcomes for IVUS- versus angio-guided PCI in patients with AMI. The primary endpoint was all-cause mortality and the secondary endpoint major adverse cardiovascular events (MACE). Mantel-Haenszel random-effects model was used to calculate pooled risk ratios (RR) with 95% confidence intervals (CI). RESULTS: Nine studies (8 observational, 1 RCT) with a total of 838.902 patients (796.953 angio-guided PCI, 41.949 IVUS-guided PCI) were included. In patients with AMI, IVUS-guided PCI was associated with a significantly lower risk of all-cause mortality (pooled RR: 0.70; 95% CI, 0.59-0.82; p < 0.01), MACE (pooled RR: 0.86; 95% CI, 0.74-0.99; p = 0.04) and target vessel revascularization (TVR) (pooled RR: 0.83; 95% CI, 0.73-0.95; p < 0.01). In the subset of patients presenting with ST-segment elevation, IVUS-guided PCI remained associated with a reduced risk for both all-cause mortality (pooled RR: 0.79; 95% CI, 0.66-0.95, p = 0.01) and MACE (pooled RR: 0.86; 95% CI, 0.74-0.99, p = 0.04). CONCLUSIONS: This is the first systematic review and meta-analysis comparing IVUS- versus angio-guided PCI in patients with AMI, showing a beneficial effect of IVUS-guided PCI on all-cause mortality, MACE and TVR. Results of ongoing dedicated prospective studies are needed to confirm these findings.

Tissue characterisation and primary percutaneous coronary intervention guidance using intravascular ultrasound: rationale and design of the SPECTRUM study.

INTRODUCTION: Intravascular ultrasound (IVUS) improves clinical outcome in patients undergoing percutaneous coronary intervention (PCI) but dedicated prospective studies assessing the safety and efficacy of IVUS guidance during primary PCI are lacking. METHODS AND ANALYSIS: The SPECTRUM study is a prospective investigator-initiated single-centre single-arm observational cohort study aiming to enrol 200 patients presenting with ST-segment elevation myocardial infarct undergoing IVUS-guided primary PCI. IVUS will be performed at baseline, postintervention and postoptimisation (if applicable), using a 40-60 MHz high-definition (HD) system. Baseline tissue characterisation includes the morphological description of culprit lesion plaque characteristics and thrombus as assessed with HD-IVUS. The primary endpoint is target vessel failure at 12 months (defined as a composite of cardiac death, target vessel myocardial infarction and clinically driven target vessel revascularisation). The secondary outcome of interest is IVUS-guided optimisation, defined as IVUS-guided additional balloon dilatation or stent placement. Other endpoints include clinical and procedural outcomes along with post-PCI IVUS findings. ETHICS AND DISSEMINATION: The protocol of this study was approved by the Ethics Committee of the Erasmus University Medical Center, Rotterdam, the Netherlands. Written informed consent is obtained from all patients. Study findings will be submitted to international peer-reviewed journals in the field of cardiovascular imaging and interventions and will be presented at international scientific meetings. TRIAL REGISTRATION NUMBER: NCT05007535.

Thrombus aspiration in acute myocardial infarction.

The success of primary percutaneous coronary intervention (PCI) in patients with ST-segment elevation myocardial infarction (STEMI) is often hampered by incomplete microvascular myocardial reperfusion owing to distal embolization of thrombus resulting in microvascular obstruction. To address this problem, thrombus aspiration devices have been developed that can be used to evacuate coronary thrombus either manually or mechanically. Thrombus aspiration has the potential to reduce the local thrombus load, minimize the need for balloon predilatation, facilitate direct stenting, prevent distal embolization, and ultimately improve myocardial reperfusion. Furthermore, thrombus aspiration has enabled us to study coronary thrombus in vivo, and has facilitated recognition of distinct mechanisms of coronary thrombosis. Clinical trials focusing on manual thrombus aspiration in primary PCI have generally shown improved myocardial reperfusion. However, in two large trials powered for clinical end points, no reduction in 1-year mortality or other adverse clinical events was observed with the use of this strategy. Moreover, one of these trials showed a marginally increased risk of stroke. Consequently, current guidelines do not recommend routine use of thrombus aspiration. Future studies should focus on the identification of subgroups of patients with STEMI who might derive benefit from manual thrombus aspiration, and establish the effect of operator performance on the efficacy and safety of the procedure.

Perioperative Cardiovascular Risk of Prior Coronary Stent Implantation Among Patients Undergoing Noncardiac Surgery.

BACKGROUND: Previous studies have observed high rates of perioperative cardiovascular events in patients with coronary stents undergoing noncardiac surgery (NCS). It is uncertain whether this finding reflects an independent association. OBJECTIVES: The goal of this study was to assess the independent relationship between prior coronary stent implantation and the occurrence of perioperative major adverse cardiac and cerebrovascular events (MACCE) and bleeding and its relation with time from stenting to NCS. METHODS: A total of 24,313 NCS cases at the Mayo Clinic (Rochester, Minnesota) from 2006 through 2011 were included in the study; 1,120 (4.6%) cases involved patients with coronary stents. MACCE was defined as death, myocardial infarction, cardiac arrest, or stroke. Age-adjusted odds ratios (aORs) were calculated after propensity adjustment for Revised Cardiac Risk Index factors and other conventional risk factors. RESULTS: The 30-day MACCE rates were 3.7% and 1.5% in stented and unstented patients, respectively (p < 0.001). The risk of MACCE was largely related to the time from stent implantation to NCS, indicating substantially elevated risk in the first year after stenting (aOR: 2.59; 95% confidence interval [CI]: 1.36 to 4.94) but not thereafter (aOR: 0.89; 95% CI: 0.59 to 1.36). Bleeding displayed a similar pattern, indicating elevated risk in the first year after stenting (aOR: 2.23; 95% CI: 1.55 to 3.21) but not thereafter (aOR: 1.07; 95% CI: 0.89 to 1.28). Subgroup analysis in patients with known stent type found that the increased risk of both MACCE and bleeding >1 month after stent implantation was not limited to only those with drug-eluting stents. CONCLUSIONS: This study found that prior coronary stent implantation is an independent risk factor for MACCE and bleeding when time from stenting to NCS is <1 year, both in patients with bare-metal and drug-eluting stents.

Characteristics of patients with false- ST-segment elevation myocardial infarction diagnoses.

BACKGROUND: A subgroup of patients presenting with suspected ST-elevation myocardial infarction (STEMI) have no culprit lesion during coronary angiography (false-positive STEMI). Little is known about patient- and system-related factors that are associated with false-positive STEMI. We evaluated the incidence, correlates, delay, final diagnosis, and outcome of patients with false-positive STEMI. METHODS: We studied 827 consecutive patients presenting with suspected STEMI between January 2011-September 2012. RESULTS: A false positive STEMI activation was identified in 68 patients (8.2%). Patients with false-positive STEMI were younger (57 vs 63 year; p=0.020), less often had hypercholesterolemia (19 vs 43%; p=0.001), and had a higher heart rate (82 vs 75 bpm; p=0.014). The association between these factors and false-positive STEMI activation persisted in multivariate analysis. The duration of symptoms to call was longer in false-positive STEMI patients (128 vs 83 min; p=0.030), although this did not reach statistical significance in multivariate analysis. Final diagnosis in patients with false-positive STEMI activation was particularly from unknown origin (41%). There were no significant differences in mortality at 30 days and one year between patients with STEMI and false-positive STEMI. CONCLUSION: The incidence of false-positive STEMI was 8.2% in patients suspected of STEMI. Patients with false-positive STEMI differ from STEMI patients in certain baseline characteristics and in patient delay. Interestingly, absence of coronary disease did not translate into better clinical outcome.

Event Rates in Randomized Clinical Trials Evaluating Cardiovascular Interventions and Devices.

Randomized clinical trials (RCTs) are considered the gold standard for evidence-based medicine. However, an accurate estimation of the event rate is crucial for their ability to test clinical hypotheses. Overestimation of event rates reduces the required sample size but can compromise the statistical power of the RCT. Little is known about the prevalence, extent, and impact of overestimation of event rates. The latest RCTs on 10 preselected topics in the field of cardiovascular interventions and devices were selected, and actual primary event rates in the control group were compared with their respective event rate estimations. We also assessed what proportion of the nonsignificant RCTs was truly able to exclude a relevant treatment effect. A total of 27 RCTs randomizing 19,436 patients were included. The primary event rate in the control group was overestimated in 20 of the 27 RCTs (74.1%) resulting in a substantial relative difference between observed and estimated event rates (mean -22.9%, 95% confidence interval -33.5% to -12.2%; median -16.3%, 95% confidence interval -30.3% to -6.5%). Event rates were particularly overestimated in RCTs on biodegradable polymer drug-eluting coronary stents and renal artery stenting. Of the 14 single end point superiority trials with nonsignificant results, only 3 (21.4%) actually resulted in truly negative conclusions. In conclusion, event rates in RCTs evaluating cardiovascular interventions and devices are frequently overestimated. This under-reported phenomenon has fundamental impact on the design of RCTs and can have an adverse impact on the statistical power of these trials to answer important questions about therapeutic strategies.

Biochemical Validation of Patient-Reported Symptom Onset Time in Patients With ST-Segment Elevation Myocardial Infarction Undergoing Primary Percutaneous Coronary Intervention.

OBJECTIVES: This study evaluated a biochemical validation of patient-reported symptom onset time in patients with ST-segment elevation myocardial infarction (STEMI). BACKGROUND: Symptom onset time is an important metric but has never been formally validated. METHODS: The Mayo Clinic Percutaneous Coronary Intervention (PCI) Registry was interrogated to obtain baseline, procedural, and outcome data on 607 STEMI patients undergoing primary PCI. Biochemical onset time was determined by backward extrapolation of serial increasing cardiac troponin T (cTnT) measurements. RESULTS: The median patient-reported onset time was 12 min later than the calculated time of first cTnT increase and was therefore estimated to be 4.2 h later than the biochemical onset time (interquartile range: 1.9 to 11.1 h; p < 0.001), assuming a 4-h interval between coronary occlusion and first cTnT increase. Conventional ischemic time showed no association with infarct size (correlation with peak cTnT: r = 0.023; p = 0.61) or 1-year mortality (hazard ratio: 0.97 per doubling; 95% confidence interval: 0.68 to 1.40; p = 0.88). However, after recalculation of ischemic time with biochemical onset time, significant associations with infarct size (r = 0.14; p = 0.001) and 1-year mortality (hazard ratio: 1.70 per doubling; 95% confidence interval: 1.20 to 2.40; p = 0.003) were found. When underestimation of ischemic time by patient-reported onset time increased, so did the risk of mortality. CONCLUSIONS: Although our point estimate should be interpreted with caution, our study indicates that the actual onset of STEMI is likely to be earlier than the patient-reported onset time. Recalculation of ischemic time with biochemical onset time greatly enhanced its prognostic value. Underestimation of ischemic time by patient-reported onset time occurred more often in high-risk patients.

Independent association between symptom onset time and infarct size in patients with ST-elevation myocardial infarction undergoing primary percutaneous coronary intervention.

Recent studies have reported on circadian variation in infarct size in ST-elevation myocardial infarction (STEMI) patients. Controversy remains as to whether this finding indicates circadian dependence of myocardial tolerance to ischemia/reperfusion injury or that it can simply be explained by confounding factors such as baseline profile and ischemic time. We assessed the clinical impact and independent association between symptom onset time and infarct size, accounting for possible subgroup differences. From a multicenter registry, 6799 consecutive STEMI patients undergoing primary percutaneous coronary intervention (PCI) between 2004 and 2010 were included. Infarct size was measured using peak creatine kinase (CK). Infarct size exhibited circadian variation with largest infarct size in patients with symptom onset around 03:00 at night (estimated peak CK 1322 U/l; 95% confidence interval (CI): 1217-1436) and smallest infarct size around 11:00 in the morning (estimated peak CK 1071 U/l; 95% CI: 1001-1146; relative reduction 19%; p = 0.001). Circadian variation in infarct size followed an inverse pattern in patients with prior myocardial infarction (p-interaction <0.001) and prior PCI (p-interaction = 0.006), although the later did not persist in multivariable analysis. Symptom onset time remained associated with infarct size after accounting for these interactions and adjusting for baseline characteristics and ischemic time. Symptom onset time did not predict one-year mortality (p = 0.081). In conclusion, there is substantial circadian variation in infarct size, which cannot be fully explained by variations in baseline profile or ischemic time. Our results lend support to the hypothesis of circadian myocardial ischemic tolerance and suggest a different mechanism in patients with prior myocardial infarction.

Intracoronary abciximab in diabetic patients with ST-segment elevation myocardial infarction undergoing primary percutaneous coronary intervention.

BACKGROUND: Although intracoronary abciximab failed to improve prognosis compared with intravenous route in unselected ST-segment elevation myocardial infarction (STEMI) patients, little is known about the role of intracoronary abciximab in diabetic patients. OBJECTIVES: To evaluate the efficacy of intracoronary abciximab administration in diabetic patients with STEMI undergoing primary percutaneous coronary intervention (PCI). METHODS: Reperfusional and clinical outcomes of intracoronary abciximab compared with intravenous bolus abciximab according to diabetic status were evaluated in a pooled analysis of five randomized trials including 3158 STEMI patients. The primary clinical endpoint of the study was the composite of death or reinfarction at 30-day follow-up. RESULTS: Among 584 diabetic patients (18.5%), the composite of death or reinfarction was significantly reduced with intracoronary abciximab compared to intravenous abciximab (4.7% vs. 8.8%; rate ratio [RR], 0.50; 95% confidence intervals [CI], 0.26-0.99; p=0.04), driven by numerically lower deaths (3.7% vs. 6.4%; RR, 0.56; 95% CI, 0.26-1.20; p=0.13). Moreover, a significant reduction in definite or probable stent thrombosis was observed in patients receiving intracoronary abciximab (1% vs. 3.5%; RR, 0.27; 95% CI, 0.07-0.99; p=0.04). Although formal tests for interaction were not significant, no clinical benefit was apparent in the cohort of STEMI patients without diabetes (n=2574). CONCLUSIONS: In diabetic patients with STEMI undergoing primary PCI, intracoronary abciximab may improve clinical outcomes as compared with standard intravenous use. These findings require confirmation in a dedicated randomized trial.

Time of symptom onset and value of myocardial blush and infarct size on prognosis in patients with ST-elevation myocardial infarction.

In patients with ST-segment elevation myocardial infarction (STEMI), the time of onset of ischemia has been associated with myocardial infarction (MI) size. Myocardial blush grade (MBG) reflects myocardial response to ischemia/reperfusion injury, which may differ according to time of the day. The aim of our study was to explore the 24-hour variation in MBG and MI size in relation to outcomes in STEMI patients. A retrospective multicenter analysis of 6970 STEMI patients was performed. Time of onset of STEMI was divided into four 6-hour periods. STEMI patients have a significant 24-hour pattern in onset of symptoms, with peak onset around 09:00 hour. Ischemic time was longest and MI size, estimated by peak creatine kinase concentration, was largest in patients with STEMI onset between 00:00 and 06:00 hours. Both MBG and MI size were independently associated with mortality. Time of onset of STEMI was not independently associated with mortality when corrected for baseline and procedural factors. Interestingly, patients presenting with low MBG between 00:00 and 06:00 hours had a better prognosis compared to other groups. In conclusion, patients with symptom onset between 00:00 and 06:00 hours have longer ischemic time and consequently larger MI size. However, this does not translate into a higher mortality in this group. In addition, patients with failed reperfusion presenting in the early morning hours have better prognosis, suggesting a 24-hour pattern in myocardial protection.