Incidence, predictors, and clinical outcomes of early stent thrombosis in acute myocardial infarction patients treated with primary percutaneous coronary angioplasty (insights from the University of Ottawa Heart Institute STEMI registry).

BACKGROUND: Early stent thrombosis (ST) remains an important complication of primary percutaneous intervention (PCI). To date, our information on angiographic and clinical predictors of early ST in ST-segment elevation myocardial infarction (STEMI) patients treated with primary PCI is limited. METHODS: We tried to evaluate the incidence, predictors, and outcomes of early ST in real-world patients treated with primary PCI. We identified all the patients presenting with STEMI between June 2004 and January 2011 who underwent primary PCI as the primary mode of revascularization. Diagnosis of ST was made as per the standard definition proposed by the Academic Research Consortium. RESULTS: The incidence of early ST was 1% among 2,303 patients treated with primary PCI. Definite and probable early ST occurred in 22 and 2 patients, respectively. Patients with early ST had higher in-hospital (P = 0.03) and 30-day mortality (P = 0.048). The rate of cardiogenic shock (P = 0.0006) and cerebrovascular accident (P = 0.0004) was also greater in the early ST group. Smaller stent diameter and lower use of intracoronary glycoprotein IIb/IIIa inhibitor were associated with higher rate of early ST. There was a trend of higher bivalirudin use in ST group, which did not reach significance (P = 0.07) On IVUS imaging, stent malapposition and uncovered plaque area were noted in 6 out of 11 cases. CONCLUSION: The incidence of early ST in primary PCI cohort is low. However, it is still associated with higher mortality and morbidity. Small stent diameter and disuse of intracoronary glycoprotein IIb/IIIa inhibitor may be associated with early ST.

Left Ventricular Outflow Tract Obstruction and Systolic Anterior Motion of the Mitral Valve in the Absence of Hypertrophic Cardiomyopathy.

Systolic anterior motion of the mitral valve is a mechanism for the development of left ventricular outflow tract (LVOT) obstruction. While often associated with left ventricular hypertrophy (LVH), a case is reported of symptomatic LVOT obstruction due to intrinsic mitral valve pathology in the absence of hypertrophy or cardiomyopathy. This case highlights the importance of recognizing isolated mitral valve pathology as a treatable cause of LVOT obstruction.

AcrB contamination in 2-D crystallization of membrane proteins: lessons from a sodium channel and a putative monovalent cation/proton antiporter.

Contamination with the multidrug transporter AcrB represents a potential pitfall in the structural analysis of recombinant membrane proteins expressed in Escherichia coli, especially when high-throughput approaches are adopted. This can be a particular problem in two-dimensional (2-D) crystallization for electron cryomicroscopy since individual crystals are too small for compositional analysis. Using a broad 'sparse matrix' of buffer conditions typically used in 2-D crystallization, we have identified at least eight unique crystal forms of AcrB. Reference to images and projection maps of these different forms can greatly facilitate the early identification of false leads in 2-D crystallization trials of other membrane proteins of interest. We illustrate the usefulness of such data by highlighting two studies of membrane proteins in our laboratories. We show in one case (a bacterial sodium channel, NaChBac) how early crystallization 'hits' could be attributed to contaminating AcrB by comparison against our AcrB crystal image database. In a second case, involving a member of the monovalent cation/proton antiporter-1 family (MPSIL0171), a comparison with the observed AcrB crystal forms allowed easy identification of reconstituted AcrB particles, greatly facilitating the eventual purification and crystallization of the correct protein in pure form as ordered helical arrays. Our database of AcrB crystal images will be of general use in assisting future 2-D crystallization studies of other membrane proteins.

Altered myocardial glucose utilization and the reverse mismatch pattern on rubidium-82 perfusion/F-18-FDG PET during the sub-acute phase following reperfusion of acute anterior myocardial infarction.

BACKGROUND: Reperfused myocardium post-acute myocardial infarction (AMI) may have altered metabolism with implications for therapy response and function recovery. We explored glucose utilization and the "reverse mismatch" (RMM) pattern (decreased F-18-fluorodeoxyglucose (FDG) uptake relative to perfusion) in patients who underwent mechanical reperfusion with percutaneous coronary intervention (PCI) for AMI. METHODS AND RESULTS: Thirty-one patients with anterior wall AMI treated with acute reperfusion, with left ventricular ejection fraction ≤45%, underwent rest rubidium-82 (Rb-82) and FDG PET 2-10 days post-AMI. Resting echocardiograms were used to assess wall motion abnormalities. Significant RMM occurred in 15 (48%) patients and was associated with a shorter time to PCI of 2.9 hours (2.2, 13.3 hours) compared to patients without significant RMM: 11.4 hours (3.9, 22.4 hours) (P = .03). Within the peri-infarct regions, segments with significant RMM were more likely to have wall motion abnormalities (OR = 2.3 (1.1, 4.7), P = .02) compared to segments without significant RMM. CONCLUSIONS: RMM is a common pattern on perfusion/FDG PET during the sub-acute phase following reperfusion of AMI and is associated with shorter times to PCI. Within the peri-infarct region, RMM occurs frequently and is more often associated with wall motion abnormalities than segments without RMM. Whether this represents a myocardial metabolic shift during the sub-acute phase of recovery warrants further study.

Lesion characteristics and coronary stent selection with computed tomographic coronary angiography: a pilot investigation comparing CTA, QCA and IVUS.

OBJECTIVE: The accurate assessment of a target coronary lesion and appropriate stent selection is important in ensuring procedural success during percutaneous coronary intervention (PCI). Though quantitative coronary angiography (QCA) and intravascular ultrasound (IVUS) are available, stent selection is most commonly performed by visual estimation alone. Computed tomographic coronary angiography (CTA) has been shown to correlate well with QCA and IVUS in the assessment of coronary stenoses and may also have a role in stent guidance. MATERIALS AND METHODS: Patients awaiting elective PCI underwent CTA. Blinded observers assessed lesion characteristics using: CTA, QCA, IVUS and visual estimation. Luminal diameters, lesion lengths, ACC/AHA lesion types and CTA-suggested stent sizes were compared. RESULTS: A total of 17 patients (26 lesions) were evaluated. There was good correlation between CTA and IVUS for luminal diameter and for lesion length (r = 0.86 and 0.71, respectively). Similarly, the inter-test variability between the two methods using the intra-class coefficient (ICC = 0.85) was similar to the inter-observer variability of IVUS (ICC = 0.90). The agreement between CTA and visual estimation for lesion type was good (K = 0.79) and was similar to the agreement between the two visual observers (K = 0.72). There was good correlation between CTA stent recommended and actual stent selected (diameter, r = 0.82; length, r = 0.64). CONCLUSIONS: If CTA data is available prior to coronary angioplasty, the reporting of luminal size, length, and lesion type may assist the clinician with coronary stent selection.