Despite the relative infancy of thoracic endografting, these procedures are now routinely used in the treatment of type B aortic dissection. The early results of endovascular treatment of acute complicated type B dissections are reasonably well characterized and suggest a substantial early mortality advantage over open surgical treatment. A recent report from the US inpatient sample has identified a considerable mortality advantage over conventional surgical repair. Less certain is the place of endovascular therapy for chronic type B dissections or in lesions that may be classified as subacute (between 2 and 6 weeks after the onset of dissection). There is relatively sparse literature reporting the outcomes of endovascular therapy in nonacute dissections.

The majority of contemporary reports detail the acute outcomes of endovascular therapy in type B aortic dissection, but the long-term outcomes are less well characterized. The incidence of graft-related complications has not been described in sufficient detail, and information regarding the long-term protection from aortic dilatation and rupture is lacking. One of the fundamental differences in the treatment of thoracic aneurysms as compared to the treatment of type B dissections is the ability of the aorta to remodel following endovascular repair. There have been some reports that suggest the aorta of acute type B dissection remodels more extensively than chronic dissections, but the remodeling of subacute dissections remains a matter of conjecture.

The VIRTUE registry was designed to evaluate the performance of one particular endograft, the Valiant Stent Graft System (Medtronic, Inc., Minneapolis, MN), in the treatment of type B aortic dissection. The registry will report the results of patients treated in the acute, subacute, and chronic phases of the disease process and will inform on both clinical and morphological outcomes. The registry aims to report outcomes to a follow- up of 3 years. The present report details the design of the VIRTUE registry. The early outcomes will be published in the European Journal of Vascular and Endovascular Surgery later this year.

METHODS AND STUDY DESIGN
The VIRTUE registry is a prospective, nonrandomized, multicenter European Clinical Registry designed to inform on the clinical and morphological outcomes of 100 patients with type B aortic dissection treated with the Valiant Thoracic Stent Graft with the Xcelerant Delivery System (Medtronic, Inc.). The primary endpoint of the registry is all-cause mortality at 12 months postprocedure. Secondary endpoints include all-cause mortality, disease-, procedure-, or device-related mortality, major complications, technical success, procedural success, reintervention, and graft-related complications. Endpoints will be recorded at 30 days (or the end of inpatient stay if longer) 3, 6, 12, 24, and 36 months. Aortic morphology will be reported after analysis of cross-sectional imaging by a core laboratory.

Written informed consent will be obtained before enrollment. Patients will be considered for inclusion in the registry if they had a type B dissection amenable to endovascular treatment and were over 18 years of age. Specific indications for inclusion were documented by the duration of the disease and were at the investigators' clinical discretion. Examples of inclusion criteria include:

  • Acute dissection (14 days from first dissection): aortic rupture, malperfusion syndromes (visceral, renal, lower limb), impending rupture (persistent pain), and refractory hypertension.
  • Subacute dissection (15–92 days): complicated/symptomatic dissection, aortic expansion > 5.5 cm, and aortic diameter > 4 cm with true and false lumens both patent.
  • Chronic dissection (7gt; 92 days): complicated/symptomatic dissection, aortic diameter > 5.5 cm, or expanding > 0.5 cm/year.

Exclusion criteria included patients with a dissection involving the ascending aorta, penetrating ulcers and intramural hematoma in the absence of dissection, ongoing infection, an estimated life expectancy < 12 months, documented connective tissue disease (eg, Marfan syndrome), and patients with a history of bleeding diathesis.

Patients were recruited from the following centers: St. Antonius Ziekenhuis, Nieuwegein, The Netherlands (Dr. R. Heijmen, 20 patients); Ospedale Sant'Orsola Malpighi, Bologna, Italy (Dr. R. Fattori, 19); St George's Vascular Institute, London, United Kingdom (Prof. M. Thompson [Principal Investigator],16); Universitätsspital Bern, Inselspital, Switzerland (Prof. Dai-Do Do, 9); Universitätsklinikum Essen, Germany (Dr. H. Eggebrecht, 7); Onze-Lieve-Vrouw Ziekenhuis, Aalst, Belgium (Dr. I. Degrieck, 7); University School of Medicine Rostock, Germany (Prof. C. Nienaber, 6); St. Mary's Hospital London, England (Prof. N. Cheshire, 5); Unità di Chirurgia Vasc, Ospedale R. Silvestrini, Perugia, Italy (Prof. P. Cao, 3); Herz-Kreislauf Zentrum der Universität Freiburg, Germany (Dr. Rylski, 2); Sahlgrenska University Hospital, Goteborg, Sweden (Prof. L. Lonn, 2); Azienda Osp Santa Maria della Misericordia, Udine, Italy (Dr. D. Gasparini, 2); Hospital Clínico Universitario San Cecilio, Granada, Spain (Prof. E. Ros Die, 1); Hospital Universitario La Paz, Madrid, Spain (Dr. G. Garzon, 1).

Cross-sectional imaging will be analyzed by a core laboratory (University of Utrecht, The Netherlands) at specified time points. Briefly, measurements will include the aortic diameter and area of both true and false lumen at four specified anatomical sites (ascending aorta, origin of the left subclavian artery, 10 cm distal to the origin of the left subclavian artery, and the origin of the celiac trunk). The true lumen index, the false lumen index, and the true/false lumen ratio will be calculated. The state of the false lumen in terms of thrombosis (patent, partially thrombosed, or thrombosed) will be documented.

EARLY RESULTS
The early results of the study are now available and will be reported this year in the European Journal of Vascular and Endovascular Surgery. This registry, specific to dissections, will inform on the long-term durability of endovascular repair in this pathology. Interestingly, the rapid pace of device evolution is evidenced by the introduction of a new delivery system for the Valiant Stent Graft, the Captivia Delivery System, which incorporates a tip capture feature for enhanced control for precise stent graft placement.

Matt Thompson, MD, FRCS, is Professor of Vascular Surgery at St George's Vascular Institute in London, United Kingdom. He has disclosed that he receives grant/research funding from Medtronic and Cook Medical and that he is a paid consultant to Abbott Vascular and GE Healthcare. Prof. Thompson may be reached at +44 208 725 3205; matt.thompson@stgeorges.nhs.uk.