Routine aspiration thrombectomy improves the diagnosis and management of embolic myocardial infarction.

OBJECTIVES: Assess the effect of aspiration thrombectomy on diagnosis and management of embolic acute myocardial infarction. BACKGROUND: Discrimination of embolic acute myocardial infarction from atherosclerotic plaque rupture/erosion prompts oral anticoagulation treatment of source of embolus, as well as avoiding unnecessary stenting and dual antiplatelet therapy. However, detection is difficult without aspiration. METHODS: We compared rates of diagnosis of embolic infarction for 2.5 years prior to (pre-RAT) and 2.5 years post routine aspiration thrombectomy (post-RAT). Baseline demographics, outcomes, and treatment strategies were also compared between the embolic infarction and atherosclerotic infarction. RESULTS: Diagnosed embolic infarction rose from 1.2% in the pre-RAT era to 2.8% in the post-RAT period (P < 0.05). In addition, more successful removal of thrombus by aspiration led to less stenting (20% vs. 55% P < 0.05) in the post-RAT period thus avoiding the hazards of "triple therapy." Embolic infarction was more frequently associated with atrial fibrillation (55% vs. 8%), had higher mortality (17% vs. 4%), and had higher rates of embolic stroke (13% vs. 0.3%) when compared with atherosclerotic MI (all P < 0.05). CONCLUSIONS: Routine aspiration thrombectomy more readily identifies embolic infarction allowing more specific therapy and avoidance of stenting and triple anticoagulant therapy.

Prevalence of coronary occlusion and outcome of an immediate invasive strategy in suspected acute myocardial infarction with and without ST-segment elevation.

The prevalence of flow-limiting coronary lesions at the time of presentation in patients with non-ST-segment elevation myocardial infarction (NSTEMI) is unknown. Because rational reperfusion strategies depend on early, accurate identification of coronary flow limitation, we performed coronary angiography at the time of presentation of patients with suspected NSTEMI. We also evaluated outcomes of an immediate interventional strategy. A comparison is made with suspected ST-segment elevation myocardial infarction (STEMI). Unselected consecutive patients with suspected STEMI or NSTEMI were enrolled in a prospective observational cohort study. Suspected STEMI was defined according to standard criteria. Suspected NSTEMI was identified by clinical evaluation of symptoms, electrocardiographic changes, persistence of ischemic pain for >20 minutes despite treatment, and/or hemodynamic instability. Biochemical evidence of myocardial necrosis on presentation was not mandatory. An immediate, around-the-clock invasive strategy was applied. Significant coronary lesions were found in 94% of 279 patients with suspected STEMI and in 90% of 125 patients with suspected NSTEMI, and coronary occlusion or flow limitation was present in 75% and 63% of patients, respectively. Immediate percutaneous coronary intervention was performed in 74% and 60%, respectively, and an additional 13% and 18%, respectively, had coronary artery bypass surgery during the index admission. In-hospital mortalities in the patients with suspected STEMI and NSTEMI were 4.7% and 5.6%, respectively. An additional 1.9% and 2.5% died at 6 months. The prevalence of coronary flow limitation in clinically suspected NSTEMI is almost as high as in suspected STEMI. Short- and long-term outcomes of an immediate invasive strategy are similar for the 2 conditions.

Absence of a 'smoker's paradox' in field triaged ST-elevation myocardial infarction patients undergoing percutaneous coronary intervention.

PURPOSE: The 'smoker's paradox' refers to the observation of favorable prognosis in current smokers following an acute myocardial infarction (AMI). Initial positive findings were in the era of fibrinolysis, with more contemporary studies finding conflicting results. We sought to determine the presence of a 'smoker's paradox' in a cohort of ST Elevation Myocardial Infarction (STEMI) patients identified via field triage, treated with primary percutaneous coronary intervention (pPCI). METHODS: This was a single center retrospective cohort study identifying consecutive STEMI patients presenting for pPCI via field triage. The primary end points were all cause mortality, major adverse cardiac events (MACE), major bleeding, in-hospital cardiac arrest and length of stay (LOS). RESULTS: A total of 382 patients were included in the study. Current smokers were more likely to be younger (p<0.00001), male (p<0.001) and have fewer comorbidities, including renal impairment (p<0.01) and a history of AMI (p<0.05). Current smokers also had a shorter ischemic time (p<0.05), were less likely to have collateral circulation (p<0.05), and more likely to have signs of pulmonary edema at presentation (p<0.05). There was no difference between smoking groups and all cause mortality (p=0.67), MACE (p=0.49), major bleeding (p=0.49) or in-hospital cardiac arrest (p=0.43). Current smokers had a shorter LOS (p<0.05). In multivariate analysis smoking status did not correlate with primary outcomes. CONCLUSION: The 'smoker's paradox' does not appear to be relevant among STEMI patients undergoing pPCI, identified via field triage. The previously documented 'smoker's paradox' may have been an indication of patient characteristics and the historical treatment of STEMI with thrombolysis. Further studies with larger numbers may be warranted.

Left bundle branch block without concordant ST changes is rarely associated with acute coronary occlusion.

BACKGROUND: The Sgarbossa score has been used to identify acute myocardial infarction on ECG in the presence of LBBB but has relied on elevated CK-MB for validation rather than angiographic evidence of vessel occlusion. METHODS: We determined (a) the presence or absence of Sgarbossa criteria with concordant (S-con) or discordant (S-dis) ST changes, (b) the presence of acute coronary occlusion or likely recent occlusion on angiography and (c) the biochemical evidence of myocardial infarction (Troponin T >0.10 µg/L, Troponin I >1.0 µg/L) in patients field-triaged with suspected AMI and LBBB. RESULTS: Between April 2004 and March 2009, 102 patients had field ECGs transmitted by paramedics for triage--8 with S-con, 26 with S-dis and 68 with LBBB alone. Acute coronary occlusion was present in 8/8 with S-con but none of the S-dis or LBBB alone patients, and in all 8 S-con patients reperfusion resulted in resolution of S-con changes. Likely culprit lesions with TIMI 3 flow were found in 3 S-dis patients but stenting did not result in resolution of S-dis. LBBB did not resolve in any patient. Troponin was elevated in 26 patients--11 with occlusion or likely culprit lesions, 15 with non-ischaemic causes. CONCLUSIONS: In the absence of S-con, LBBB is not associated with acute coronary occlusion and should not be used as criteria for reperfusion therapy in myocardial infarction.

Procedural and in-patient outcomes in patients aged 80 years or older undergoing contemporary primary percutaneous coronary intervention.

AIMS: Patients aged ≥80 years are often excluded or under-represented in trials assessing treatment modalities in STEMI. We assessed in-patient outcomes in elderly patients undergoing contemporary primary PCI (PPCI). METHODS AND RESULTS: From Sept 2005 to July 2011 patients undergoing PPCI in our centre were identified. Demographic details, procedural data and in-patient outcomes were collated. Those aged ≥80 years were compared with those aged <80 years. In the study period 1,218 patients required PPCI, of which 224(18.4%) were ≥80 years. The elderly cohort were more likely to be female (44.3% vs. 20.3%; p<0.001), and have significant comorbidities. Times from first medical contact until TIMI 3 flow were similar between the two groups (medien 102 min vs. 109 min; p=0.19). There was no difference in rates of PCI success (97.3% vs. 98.3%; p=0.24), drug-eluting stent use (63.5% vs. 63.3%; p=1.00) and number of stents used. In-patient outcomes were worse in the elderly cohort with significantly higher rates of death (11.2% vs. 3.7%; p<0.001) and acute kidney injury (12.9% vs. 4.0%; p<0.001), with a trend towards more post-procedure cardiovascular accidents (CVA), access site complications and reinfarction. Length of stay was significantly longer in the elderly cohort (median days 5 vs. 3; p<0.001). CONCLUSIONS: Important demographic differences exist in very elderly patients presenting with STEMI compared to younger patients though procedural data and PCI success rates are similar between the two groups. Those aged ≥80 years have significantly worse in-patient outcomes though death rates are not as high as historical data suggests.