Revascularization for Unprotected Left Main Coronary Artery Disease: An Evolution in Clinical Decision Making

Coronary artery bypass grafting (CABG) has been considered the standard therapy for unprotected (nonrevascularized) left main coronary disease (ULM). However, increasing experience with ULM percutaneous coronary intervention (PCI) has resulted in high procedural success and favorable early and late clinical outcomes. In particular, reduction in clinical restenosis with drug-eluting stents, evolution of procedural technique, and demonstration of favorable outcomes from comparative trials with CABG have promoted consideration of PCI as an alternative revascularization strategy in selected patients with ULM disease. This review summarizes the results from comparative studies examining PCI versus CABG for ULM disease, discusses changing indications for ULM PCI and identifies outstanding issues that must be considered before further advancing treatment recommendations

Randomized comparison of minimally invasive direct coronary artery bypass surgery versus sirolimus-eluting stenting in isolated proximal left anterior descending coronary artery stenosis

OBJECTIVES: The purpose of this randomized study was to compare sirolimus-eluting stenting (SES) with minimally invasive direct coronary artery bypass (MIDCAB) surgery for patients with isolated proximal left anterior descending (LAD) coronary artery disease. BACKGROUND: Bare-metal stenting is inferior to MIDCAB surgery in patients with isolated proximal LAD lesions due to a higher reintervention rate with similar results for mortality and reinfarction. SES are effective in restenosis reduction. METHODS: A total of 130 patients with significant proximal LAD coronary artery disease were randomized to either SES (n = 65) or MIDCAB surgery (n = 65). The primary clinical end point was noninferiority in freedom from major adverse cardiac events (MACE), such as cardiac death, myocardial infarction, and the need for target vessel revascularization within 12 months. RESULTS: Follow-up was completed for all patients. MACE occurred in 7.7% of patients after stenting, as compared with 7.7% after surgery (p = 0.03 for noninferiority). The individual components of the combined end point revealed mixed results. Although noninferiority was revealed for the difference in death and myocardial infarction (1.5% vs. 7.7%, noninferiority p < 0.001), noninferiority was not established for the difference in target vessel revascularization (6.2% vs. 0%, noninferiority p = 0.21). Clinical symptoms improved significantly in both treatment groups in comparison with baseline, and the percentage of patients free from angina after 12 months was 81% versus 74% (p = 0.49). CONCLUSIONS: In isolated proximal LAD disease, SES is noninferior to MIDCAB surgery at 12-month follow-up with respect to MACE at a similar relief in clinical symptoms

Frequency and pattern of de-novo three-vessel and left main coronary artery disease; insights from single center enrolment in the SYNTAX study

Objectives: To characterize the current patient population regarding extent and pattern of coronary artery disease (CAD) in a routine cardiac catheterization practice with special focus on de-novo three-vessel coronary artery and/or left main disease (3-VD/LM) during enrolment in the SYNTAX study (synergy between PCI with Taxus drug-eluting stent and cardiac surgery) comparing percutaneous coronary intervention (PCI) with drug-eluting stents (DES) and coronary artery bypass grafting (CABG) in 3-VD/LM. Methods: During a 4-month study enrolment period, a total of 3319 consecutive adult patients undergoing coronary angiography were prospectively recorded. Patients with de-novo 3-VD/LM were screened in the daily heart team conference by interventional cardiologists and cardiac surgeons concerning suitability for Study enrolment. Complexity of CAD was quantified by the SYNTAX score. Results: A total of 694 patients (20.9%) presented with 3-VD/LM, of which 271 had previous CABG and 232 previous PCI treatment. Of the 191 patients with de-novo 3-VD/LM, SYNTAX study exclusion criteria were present in 87 patients consisting mostly of acute myocardial infarction (n = 47) or concomitant indications for additional heart Surgery (n = 35). A total of 104 patients (54.4% of all screened) were potentially suitable for study enrolment. Of these, 13 patients refused study participation, 10 presented with uncertain protocol adherence and 6 were already participating in other cardiovascular trials. A total of 67 patients were therefore enrolled in the SYNTAX study, representing 9.7% of 3-VD/LM and 35.1% of all, screened patients. Twenty-four patients were not amenable for PCI and were therefore assigned to the CABG registry. Compared to the randomized cohort, these patients had more complex CAD (SYNTAX score 34 vs 26, p = 0.003) with significantly more chronic coronary vessel occlusion (70.8% vs 22.5%, p, = 0.04). In the randomized cohort, CABG and PCI patients were comparable in age (PCI 69.7 years vs CABG 67.2 years), additive EuroSCORE (4.8 vs 4.4), EF (57.8% vs 52.4%), number of coronary lesions (4.5 vs 4.6), left main disease (42.9% vs 52.6%) and coronary vessel occlusion. Conclusions: Patients with de-novo 3-VD/LM represented a small proportion of patients undergoing coronary angiography at our center. However, SYNTAX study inclusion and randomization rates of these screened patients were high. Chronic vessel occlusion and high SYNTAX scores were more common in CABG registry patients compared to randomized patients. (C) 2008 European Association for Cardio-Thoracic Surgery. Published by Elsevier B.V. All rights reserved

Zuechtung von defektarmen dotierten und undotierten GaAs-Einkristallen mit dem vertikalen Gradient-Freezing-Verfahren Kurze Darstellung der Ergebnisse und Abschlussbericht

Multi zone furnaces, automation concepts and laboratory technologies have been developed using the Vertical Gradient Freeze technique for single crystal growth of GaAs with the aim to produce a low dislocation density. The crystallization prozess is performed by an electronically controlled temperature field without moving the furnace or the sample. A command variables generator free programable yields the temperature time programs for the fully automatized growth process. On the basis of a complex process simulation the crystal growth rate, the As partial pressure as well as the temporal and local temperature gradients could be adjusted with high precision and optimized by systematic growth experiments. The crystals grown are characterized by dislocation densities up 1 to 3 x 10&quot;3 cm&quot;-&quot;2, a large area cellular structure and a low density of microdefects. Si-doped and semi-insulating crystals with reproducible physical properties were grown both in (100) and (111) orientation, respectively. The possibility of affecting the crystal properties by post-growth annealing was shown experimentally. (orig.)SIGLEAvailable from TIB Hannover: F95B346+a / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekBundesministerium fuer Forschung und Technologie (BMFT), Bonn (Germany)DEGerman