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Featured researches published by Iassen Michev.


Circulation | 2010

Thirty-Day Results of the SAPIEN Aortic Bioprosthesis European Outcome (SOURCE) Registry A European Registry of Transcatheter Aortic Valve Implantation Using the Edwards SAPIEN Valve

Martyn Thomas; Gerhard Schymik; Thomas Walther; Dominique Himbert; Thierry Lefèvre; Hendrik Treede; Holger Eggebrecht; Paolo Rubino; Iassen Michev; Rüdiger Lange; William N. Anderson; Olaf Wendler

Background— Transcatheter aortic valve implantation was developed to mitigate the mortality and morbidity associated with high-risk traditional aortic valve replacement. The Edwards SAPIEN valve was approved for transcatheter aortic valve implantation transfemoral delivery in the European Union in November 2007 and for transapical delivery in January 2008. Methods and Results— The SAPIEN Aortic Bioprosthesis European Outcome (SOURCE) Registry was designed to assess the initial clinical results of the Edwards SAPIEN valve in consecutive patients in Europe after commercialization. Cohort 1 consists of 1038 patients enrolled at 32 centers. Patients who were treated with the transapical approach (n=575) suffered more comorbidities than the transfemoral patients (n=463), resulting in a significantly higher logistic EuroSCORE (29.1% versus 25.7%; P<0.001). Therefore, these groups are considered different, and outcomes cannot be compared. Overall short-term procedural success was observed in 93.8%. The incidence of valve embolization was 0.3% (n=3), and coronary obstruction was reported for 0.6% (n=6 cases). Incidence of stroke was 2.5% and similar for both procedural approaches. Thirty-day mortality was 6.3% in transfemoral patients and 10.3% in transapical patients. The occurrence of vascular complications was not a predictor of <30-day mortality in the transfemoral population. Conclusion— Technical proficiency can be learned and adapted readily as demonstrated by the short-term procedural success rate and low 30-day mortality rates reported in the SOURCE Registry. Specific complication management and refinement of patient selection are needed to further improve outcomes.


Circulation | 2007

Incidence and Predictors of Drug-Eluting Stent Thrombosis During and After Discontinuation of Thienopyridine Treatment

Flavio Airoldi; Antonio Colombo; Nuccia Morici; Azeem Latib; John Cosgrave; Lutz Buellesfeld; Erminio Bonizzoni; Mauro Carlino; Ulrich Gerckens; Cosmo Godino; Gloria Melzi; Iassen Michev; Matteo Montorfano; Giuseppe Sangiorgi; Asif Qasim; Alaide Chieffo; Carlo Briguori; Eberhard Grube

Background— The need for prolonged aspirin and thienopyridine therapy and the risk of stent thrombosis (ST) remain as drawbacks associated with drug-eluting stents. Methods and Results— A prospective observational cohort study was conducted between June 2002 and January 2004 on 3021 patients consecutively and successfully treated in 5389 lesions with drug-eluting stents. Detailed patient information was collected on antiplatelet therapy. We analyzed the incidence of ST throughout the 18-month follow-up period and its relationship with thienopyridine therapy. ST occurred in 58 patients (1.9%) at 18 months. Forty-two patients (1.4%) experienced the event within 6 months of stent implantation. Acute myocardial infarction (fatal or nonfatal) occurred in 46 patients (79%) and death in 23 patients (39%) with ST. The median interval from discontinuation of thienopyridine therapy to ST was 13.5 days (interquartile range 5.2 to 25.7 days) for the first 6 months and 90 days (interquartile range 30 to 365 days) between 6 and 18 months. On multivariable analysis, the strongest predictor for ST within 6 months of stenting was discontinuation of thienopyridine therapy (hazard ratio, 13.74; 95% CI, 4.04 to 46.68; P<0.001). Thienopyridine discontinuation after 6 months did not predict the occurrence of ST (hazard ratio, 0.94; 95% CI, 0.30 to 2.98; P=0.92). Conclusions— Discontinuation of thienopyridine therapy was the major determinant of ST within the first 6 months, but insufficient information is available to determine whether there is benefit in continuing a thienopyridine beyond 6 months.


Circulation | 2005

Early and Mid-Term Results of Drug-Eluting Stent Implantation in Unprotected Left Main

Alaide Chieffo; Goran Stankovic; Erminio Bonizzoni; Eleftheria Tsagalou; Ioannis Iakovou; Matteo Montorfano; Flavio Airoldi; Iassen Michev; Massimo Giuseppe Sangiorgi; Mauro Carlino; Giancarlo Vitrella; Antonio Colombo

Background—The safety and efficacy of percutaneous coronary intervention in unprotected left main (ULM) coronary arteries are still a matter of debate. Methods and Results—All consecutive patients who had a sirolimus-eluting stent (Cypher, Cordis, Johnson and Johnson Co) or a paclitaxel-eluting stent (Taxus, Boston Scientific) electively implanted in de novo lesions on unprotected left main were analyzed. Patients treated with a drug-eluting stent (DES) were compared with the historical group of consecutive patients treated with bare metal stent (BMS). Eighty-five patients were treated with DES; 64 had BMS implantation. Patients treated with DES had lower ejection fractions (51.1±11% versus 57.4±13%, P=0.002) and were more often diabetics (21.2% versus 10.9%, P=0.12) with more frequent distal left main involvement (81.2% versus 57.8%, P=0.003). Furthermore, in the DES group, smaller vessels (3.33±0.6 versus 3.7±0.7 mm, respectively; P=0.0001) with more lesions (2.94±1.6 versus 2.25±1.3, P=0.004) and vessels (2.03±0.69 versus 1.8±0.72, P=0.05) were treated with longer stents (24.3±12 versus 15.8±8.6 mm, P=0.0001). Despite the higher-risk patients and lesion profiles in the DES group, the incidence of major cardiac events at a 6-month clinical follow-up was lower in the DES than in the BMS group (20.0% versus 35.9%, respectively; P=0.039). Moreover, cardiac deaths occurred in 3 DES patients (3.5%), as compared with 6 (9.3%) in the BMS group (P=0.17). Conclusions—In this early experience with DES in unprotected left main, this procedure appears safe with favorable and improved clinical results as compared with historical control subjects with a BMS. A randomized study comparing surgery appears justified at present.


Circulation | 2007

Renal insufficiency following contrast media administration trial (REMEDIAL) : A randomized comparison of 3 preventive strategies

Carlo Briguori; Flavio Airoldi; Davide D'Andrea; Erminio Bonizzoni; Nuccia Morici; Amelia Focaccio; Iassen Michev; Matteo Montorfano; Mauro Carlino; John Cosgrave; Bruno Ricciardelli; Antonio Colombo

Background— Volume supplementation by saline infusion combined with N-acetylcysteine (NAC) represents an effective strategy to prevent contrast agent–induced nephrotoxicity (CIN). Preliminary data support the concept that sodium bicarbonate and ascorbic acid also may be effective in preventing CIN. Methods and Results— Three hundred twenty-six consecutive patients with chronic kidney disease, referred to our institutions for coronary and/or peripheral procedures, were randomly assigned to prophylactic administration of 0.9% saline infusion plus NAC (n=111), sodium bicarbonate infusion plus NAC (n=108), and 0.9% saline plus ascorbic acid plus NAC (n=107). All enrolled patients had serum creatinine ≥2.0 mg/dL and/or estimated glomerular filtration rate <40 mL · min−1 · 1.73 m−2. Contrast nephropathy risk score was calculated in each patient. In all cases, iodixanol (an iso-osmolar, nonionic contrast agent) was administered. The primary end point was an increase of ≥25% in the creatinine concentration 48 hours after the procedure (CIN). The amount of contrast media administered (179±102, 169±92, and 169±94 mL, respectively; P=0.69) and risk scores (9.1±3.4, 9.5±3.6, and 9.3±3.6; P=0.21) were similar in the 3 groups. CIN occurred in 11 of 111 patients (9.9%) in the saline plus NAC group, in 2 of 108 (1.9%) in the bicarbonate plus NAC group (P=0.019 by Fisher exact test versus saline plus NAC group), and in 11 of 107 (10.3%) in the saline plus ascorbic acid plus NAC group (P=1.00 versus saline plus NAC group). Conclusions— The strategy of volume supplementation by sodium bicarbonate plus NAC seems to be superior to the combination of normal saline with NAC alone or with the addition of ascorbic acid in preventing CIN in patients at medium to high risk.


Circulation | 2006

Percutaneous Treatment With Drug-Eluting Stent Implantation Versus Bypass Surgery for Unprotected Left Main Stenosis A Single-Center Experience

Alaide Chieffo; Nuccia Morici; Francesco Maisano; Erminio Bonizzoni; John Cosgrave; Matteo Montorfano; Flavio Airoldi; Mauro Carlino; Iassen Michev; Gloria Melzi; Giuseppe Sangiorgi; Ottavio Alfieri; Antonio Colombo

Background— Improvements in results with percutaneous coronary intervention (PCI) with drug-eluting stents (DES) may extend their use in patients with left main coronary artery (LMCA) stenosis. Methods and Results— Two hundred forty-nine patients with LMCA stenosis were treated with PCI and DES implantation (n=107) or coronary artery bypass grafting (CABG) (n=142), in a single center, between March 2002 and July 2004. A propensity analysis was performed to adjust for baseline differences between the two cohorts. At 1 year, there was no statistical difference in the occurrence of death in PCI versus CABG both for the unadjusted (OR=0.291; 95% CI=0.054 to 1.085; P=0.0710) and adjusted analyses (OR=0.331; 95% CI=0.055 to 1.404; P=0.1673). PCI was correlated to a lower occurrence of the composite end points of death and myocardial infarction (unadjusted OR=0.235; 95% CI=0.048 to 0.580; P=0.0002; adjusted OR=0.260; 95% CI=0.078 to 0.597; P=0.0005) and death, myocardial infarction, and cerebrovascular events (unadjusted OR=0.300; 95% CI=0.102 to 0.617; P=0.0004; adjusted OR=0.385; 95% CI=0.180 to 0.819; P=0.01). No difference was detected in the occurrence of major adverse cardiac and cerebrovascular event at the unadjusted (OR=0.675; 95% CI=0.371 to 1.189; P=0.1891) and adjusted analyses (OR=0.568; 95% CI=0.229 to 1.344; P=0.2266). Conclusions— At 1 year, in this single-center, retrospective experience, there was no difference in the degree of protection against death, stroke, myocardial infarction, and revascularization between PCI with DES and CABG for LMCA disease.


European Heart Journal | 2010

Percutaneous mitral valve repair with the MitraClip system: acute results from a real world setting.

Corrado Tamburino; Gian Paolo Ussia; Francesco Maisano; Davide Capodanno; Salvatore Scandura; Antonio Colombo; Andrea Giacomini; Iassen Michev; Sarah Mangiafico; Valeria Cammalleri; Marco Barbanti; Ottavio Alfieri

Aims This study sought to evaluate the feasibility and early outcomes of a percutaneous edge-to-edge repair approach for mitral valve regurgitation with the MitraClip® system (Evalve, Inc., Menlo Park, CA, USA). Methods and results Patients were selected for the procedure based on the consensus of a multidisciplinary team. The primary efficacy endpoint was acute device success defined as clip placement with reduction of mitral regurgitation to ≤2+. The primary acute safety endpoint was 30-day freedom from major adverse events, defined as the composite of death, myocardial infarction, non-elective cardiac surgery for adverse events, renal failure, transfusion of >2 units of blood, ventilation for >48 h, deep wound infection, septicaemia, and new onset of atrial fibrillation. Thirty-one patients (median age 71, male 81%) were treated between August 2008 and July 2009. Eighteen patients (58%) presented with functional disease and 13 patients (42%) presented with organic degenerative disease. A clip was successfully implanted in 19 patients (61%) and two clips in 12 patients (39%). The median device implantation time was 80 min. At 30 days, there was an intra-procedural cardiac tamponade and a non-cardiac death, resulting in a primary safety endpoint of 93.6% [95% confidence interval (CI) 77.2–98.9]. Acute device success was observed in 96.8% of patients (95% CI 81.5–99.8). Compared with baseline, left ventricular diameters, diastolic left ventricular volume, diastolic annular septal–lateral dimension, and mitral valve area significantly diminished at 30 days. Conclusion Our initial results with the MitraClip device in a very small number of patients indicate that percutaneous edge-to-edge mitral valve repair is feasible and may be accomplished with favourable short-term safety and efficacy results.


Circulation | 2007

Favorable Long-Term Outcome After Drug-Eluting Stent Implantation in Nonbifurcation Lesions That Involve Unprotected Left Main Coronary Artery A Multicenter Registry

Alaide Chieffo; Seung Jung Park; Marco Valgimigli; Young H. Kim; Joost Daemen; Imad Sheiban; Alessandra Truffa; Matteo Montorfano; Flavio Airoldi; Giuseppe Sangiorgi; Mauro Carlino; Iassen Michev; Cheol Whan Lee; Myeong Ki Hong; Seong Wook Park; Claudio Moretti; Erminio Bonizzoni; Renata Rogacka; Patrick W. Serruys; Antonio Colombo

Background— The presence of a lumen narrowing at the ostium and the body of an unprotected left main coronary artery but does not require bifurcation treatment is a class I indication of surgical revascularization. Methods and Results— A total of 147 consecutive patients who had a stenosis in the ostium and/or the midshaft of an unprotected left main coronary artery (treatment of the bifurcation not required) and were electively treated with percutaneous coronary intervention and sirolimus-eluting stents (n=107) or paclitaxel-eluting stents (n=40) in 5 centres were included in this registry. In 72 patients (almost 50%), intravascular ultrasound guidance was performed. Procedural success was achieved in 99% of the patients; in 1 patient with stenosis in the left main coronary artery ostium, a >30% residual stenosis persisted at the end of the procedure, and the patient was referred for coronary artery bypass graft surgery. During hospitalization, no patients experienced a Q-wave myocardial infarction or died. One patient died 19 days after the procedure because of pulmonary infection. At long-term clinical follow-up (886±308 days), 5 patients had died; 7 patients had target vessel revascularization (5 repeat percutaneous coronary interventions and 2 coronary artery bypass graft surgeries), and of these only 1 patient had a target lesion revascularization. Angiographic follow-up was performed in 106 patients (72%) with a late loss of −0.01 mm. Restenosis in the left main trunk occurred only in 1 patient (0.9%). Conclusions— Percutaneous coronary intervention with sirolimus-eluting stents or paclitaxel-eluting stents implantation in nonbifurcation left main coronary artery lesions appears safe with a long-term major adverse clinical event rate of 7.4% and a restenosis rate of 0.9%.


Catheterization and Cardiovascular Interventions | 2005

Treating chronic total occlusions using subintimal tracking and reentry: The STAR Technique

Antonio Colombo; Ghada W. Mikhail; Iassen Michev; Ioannis Iakovou; Flavio Airoldi; Alaide Chieffo; Renata Rogacka; Mauro Carlino; Matteo Montorfano; Giuseppe Sangiorgi; Nicola Corvaja; Goran Stankovic

Successful recanalization of coronary total occlusions (CTOs) remains an area where improvements are needed. We propose an approach similar to the one utilized in treating some peripheral artery occlusions and aimed to create a subintimal dissection with distal reentry. A 0.014′ hydrophilic wire with a J‐configuration is utilized for this purpose. We applied this technique to CTO of native coronaries in 31 patients where previous attempts failed in 21 of them (67%). The right coronary artery (RCA) was the index vessel in 87% of patients. Recanalization of the vessel and of most of distal branches was achieved in 21 patients; patency of at least one major distal branch was achieved in 9 patients. Drug‐eluting stents (DESs) were implanted in 53% of patients. Three patients had intraprocedural vessel perforation without consequences. Five patients (16%) had in‐hospital non‐Q‐wave myocardial infarction. No other adverse events occurred at a mean follow‐up of 5.1 ± 3.7 months except for one noncardiac death. Angiographic follow‐up was performed in 21 (67%) patients and 53% of them developed restenosis. Reintervention on the target vessel was performed in 11 patients (52%). Complete success with the procedure was originally obtained in 8 of the 10 patients who did not develop restenosis and in 8 of them DESs were originally implanted. This technique appears a promising approach to recanalize difficult total occlusions, particularly the ones localize on the RCA, which has the most important side branches located distally. Catheter Cardiovasc Interv 2005;64:407–411.


Jacc-cardiovascular Interventions | 2010

Outcomes after transcatheter aortic valve implantation with both Edwards-SAPIEN and CoreValve devices in a single center: the Milan experience.

Cosmo Godino; Francesco Maisano; Matteo Montorfano; Azeem Latib; Alaide Chieffo; Iassen Michev; Rasha Al-Lamee; Marta Bande; Marco Mussardo; Francesco Arioli; Alfonso Ielasi; Micaela Cioni; Maurizio Taramasso; Irina Arendar; Antonio Grimaldi; Pietro Spagnolo; Alberto Zangrillo; Ottavio Alfieri; Antonio Colombo

OBJECTIVES Our aim was to assess clinical outcome after transcatheter aortic valve implantation (TAVI) performed with the 2 commercially available valves with 3 delivery approaches selected in a stepwise fashion. BACKGROUND Limited data exist on the results of a comprehensive TAVI program using different valves with transfemoral, transapical, and transaxillary approaches for treatment of severe aortic stenosis. METHODS We report 30-day and 6-month outcomes of high-risk patients consecutively treated in a single center with either the Medtronic-CoreValve (MCV) (Medtronic, Minneapolis, Minnesota) or Edwards-SAPIEN valve (ESV) (Edwards Lifesciences, Irvine, California) delivered via the transfemoral or transaxillary approaches and ESV via the transapical approach. RESULTS A total of 137 patients underwent TAVI: 107 via transfemoral (46 MCV and 61 ESV), 15 via transaxillary (12 MCV and 3 ESV), and 15 via transapical approach. After the transfemoral approach, the procedural success rate was 93.5%, and major vascular complication rate was 20.6%. No intra-procedural deaths occurred. The procedural success rates of transapical and transaxillary approaches were 86.6% and 93.3%, respectively. The 30-day mortality rate was 0.9% in transfemoral group and 13.3% in transapical, and no deaths occurred after transaxillary access. Cumulative death rate at 6 months was 12.2% in transfemoral, 26.6% in transapical, and 18.2% in transaxillary groups. At multivariable analysis, logistic European System for Cardiac Operative Risk Evaluation, body surface area, and history of cerebrovascular disease were significantly associated with an increased risk of major adverse cardiac and cerebrovascular events. CONCLUSIONS Routine TAVI using both MCV and ESV with a selection of approaches is feasible and allows treatment of a wide range of patients with good overall procedural success rates and 30-day and 6-month outcomes.


Heart | 2005

Treatment of bifurcation lesions with two stents: one year angiographic and clinical follow up of crush versus T stenting

L. Ge; Ioannis Iakovou; John Cosgrave; Pierfrancesco Agostoni; Flavio Airoldi; Giuseppe Sangiorgi; Iassen Michev; Alaide Chieffo; Matteo Montorfano; Mauro Carlino; Nicola Corvaja; Antonio Colombo

Objectives: To compare long term outcomes of the crush versus the T technique in bifurcation lesions. Design: 182 consecutive patients were identified who underwent percutaneous coronary interventions for bifurcation lesions with drug eluting stents between April 2002 and January 2004. Two techniques were used according to the operator’s discretion: crush (group C, n  =  121) or T (group T, n  =  61). Results: In-hospital outcome differed significantly between the two groups. Angiographic follow up was available for 142 (78%) patients. Groups C and T did not differ significantly regarding late loss (0.42 (0.39) mm v 0.34 (0.35) mm, p  =  0.52) and rate of restenosis (16.2% v 13.0%, p  =  0.80) in both the main and the side branch without final kissing balloon post-dilatation. However, when final kissing balloon post-dilatation was performed, group C had significantly lower late lumen loss (0.23 (0.21) mm v 0.37 (0.33) mm, p  =  0.02) and restenosis rate (8.6% v 26.5%, p  =  0.04) in the side branch. At one year’s clinical follow up, group C compared with group T had lower rates of target lesion revascularisation (14.0% v 31.1%, p  =  0.01) and target vessel revascularisation (16.5% v 32.8%, p  =  0.02). Conclusions: In non-selected bifurcation lesions treated with drug eluting stents, the restenosis rate remains relatively high in the side branch. Compared with the T stenting technique, crush stenting with kissing balloon post-dilatation is associated with a reduced rate of restenosis in the side branch.

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Dive into the Iassen Michev's collaboration.

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Antonio Colombo

Vita-Salute San Raffaele University

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Matteo Montorfano

Vita-Salute San Raffaele University

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Flavio Airoldi

Vita-Salute San Raffaele University

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Alaide Chieffo

Vita-Salute San Raffaele University

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Mauro Carlino

Vita-Salute San Raffaele University

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Giuseppe Sangiorgi

University of Rome Tor Vergata

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John Cosgrave

Vita-Salute San Raffaele University

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Ioannis Iakovou

Vita-Salute San Raffaele University

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Nicola Corvaja

Vita-Salute San Raffaele University

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Gloria Melzi

Vita-Salute San Raffaele University

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