Mechanisms of Late Stent Malapposition After Primary Stenting in ST-Elevation Myocardial Infarction: A Subanalysis of the Selection Trial

Background: One of the major predictors of late stent malapposition (LSM) is primary stenting in acute myocardial infarction. However, mechanisms of LSM are still under debate.
Methods: Patients with ST-elevation myocardial infarction (STEMI) and enrolled in the SELECTION trial (38 patients in the paclitaxel-eluting stent, PES, and 35 in the bare metal stent, BMS, cohort) were retrospectively analyzed to evaluate LSM, by means of intravascular ultrasound (IVUS) data recorded at the index and 7-month follow-up procedures.
Results: Stent malapposition was documented in 21 lesions in 21 patients (28.8%): in 8 of these 21 patients (38.1%) it was LSM. Although statistical significance was not reached, LSM was more frequent after PES than BMS implantation (15.8% vs. 5.7%). LSM was mainly located within the body of the stent (62.5% of the cases). At the LSM segment, a significant increase of vessel area (19.2 ± 3.3 mm² vs. 21.9 ± 5.3 mm², P = 0.04) and a reduction of plaque area (12.6 ± 4.6 mm² vs. 9.1 ± 3.9 mm², P = 0.04) were observed at IVUS between the index and follow-up procedure.
Conclusions: After primary stenting for STEMI, LSM seems to be more frequent after PES rather than BMS implantation. In the STEMI setting, possible mechanisms leading to LSM include positive remodeling and plaque mass decrease.     

Low‐Risk Profile for Malignant Ventricular Arrhythmias and Sudden Cardiac Death after Surgical Ventricular Reconstruction

Background: Although it has been recently demonstrated that there was no significant difference in total survival and clinical outcomes between patients who underwent coronary artery bypass grafting (CABG) with or without surgical ventricular reconstruction (SVR), the question of whether or not SVR decreases the arrhythmic risk profile in this population has not been clarified yet. Objective: To determine the real incidence of sudden cardiac death (SCD) and sustained ventricular tachycardia/ventricular fibrillation (sustained VT/VF) in patients following CABG added to SVR and to define their clinical and echocardiographic parameters predicting in‐hospital and long‐term arrhythmic events (SCD + sustained VT/VF). Methods: Pre‐ and postoperative clinical and echocardiographic values as well as postoperative electrocardiogram Holter data of 65 patients (21 female, 63 ± 11 years) who underwent SVR + CABG were retrospectively evaluated. Results: Mean follow‐up was 1,105 ± 940 days. At 3 years, the SCD‐free rate was 98% and the rate free from arrhythmic events was 88%. Multivariate logistic analysis identified a preoperative left ventricular end‐systolic volume index (LVESVI) > 102 mL/m² (odds ratio [OR] 1.4, confidence interval [CI] 1.073–1.864, P = 0.02; sensitivity 100%, specificity 94%) and a postoperative pulmonary artery systolic pressure (PASP) > 27 mmHg (OR 2.3, CI 1.887–4.487, P = 0.01; sensitivity 100%, specificity 71%) as independent predictors of arrhythmic events. Conclusions: Our and previous studies report a low incidence of arrhythmic events in patients following SVR added to CABG, considering the high‐risk profile of the study population. A preoperative LVESVI > 102 mL/m² and a postoperative PASP > 27 mmHg had a good sensitivity and specificity in predicting arrhythmic events. (PACE 2010; 33:1054–1062)     

Interactions of Monoamine Oxidase Inhibitors,N-Acetylenic Analogues of Tryptamine,with Rat Liver Microsomal Cytochrome P450

Abstract— Interactions between some novel and potent monoamine oxidase inhibitors (MAOIs), acetylenic analogues of tryptamine, and rat liver microsomal cytochrome P450 (P450) as evidenced by visible spectra analysis were analysed. Compounds with a secondary aliphatic amine moiety throughout induced type II difference spectra and exhibited the highest affinity for P450, whereas tertiary amines induced type I spectral changes and showed diminished affinity. P450 dependent aniline hydroxylase activity was inhibited by all compounds in an irreversible time-dependent manner. Only tertiary aliphatic amines constituted the substrate for P450-dependent N-demethylase activity, with comparable kinetic parameters. The N-demethylated metabolites were identified by thin-layer chromatography and mass-spectrometric analyses. These findings describe the role of P450-dependent microsomal mono-oxygenase systems in the metabolism of some MAOI acetylenic tryptamine derivatives and the possible hepatic contribution to adverse interactions between MAOIs, endobiotics and sympathomimetic compounds.     

Treatment of Autoimmune Hemolytic Anemia in Children with Azathioprine (Imuran)

Three cases of autoimmune hemolytic anemia in infants are described. Thisdisease is very rare in the first few months of life. One case (No. 3)was complicated with a rare hemoglobinopathy, which may have been coincidental. Corticosteroid treatment in larges doses was partially and temporarily effective in controlling the disease. Immunosuppressive therapy (azathioprine = Imuran, 2-5 mg./Kg./day) produced a complete cure in Case 1 and allowed a marked decrease in steroid doses in the other two cases. Mostprobably, a vicious circle of autoimmunity was broken by this drug. Failureto gain weight on steroids was more than compensated for by the clear-cut "catch-up growth" in Case 1, even though Imuran was being given. Indications regarding precautions and dosage of azathioprine are stated. The exactmode of action of these drugs is discussed in an attempt to explain the natureof immunosuppression.

Submitted on October 25, 1965 Accepted on May 1, 1966