The accompanying study by Roselli et al1Roselli E.E. Arko 3rd, F.R. Thompson M.M. Valiant Mona LSA Trial InvestigatorsResults of the Valiant Mona LSA early feasibility study for descending thoracic aneurysms.J Vasc Surg. 2015; 62: 1465-1472Abstract Full Text Full Text PDF PubMed Scopus (70) Google Scholar is noteworthy for a couple of reasons: this first-in-man study of “safety and efficacy” was performed (mainly) in the United States through participation in the United States Food and Drug Administration's newly developed Innovation Pathway, and the study device provides a much needed all-endovascular option for the treatment of aneurysms involving the proximal descending thoracic aorta. As described in Roselli et al, the cuff-based side branch of the Valiant Mona LSA stent graft (Medtronic, Minneapolis, Minn) preserves flow to the subclavian artery in an attempt to minimize the risk of stroke, paraplegia, and left hand ischemia. The results of this study confirm the feasibility of the approach. All of the stent grafts and their branches were implanted as intended. The case for safety, efficacy, and durability is less clear. As reported in Table III, six patients (67%) sustained “procedure-related” serious adverse events, and strokes occurred in three (33%), all of which were symptomatic and visible on computed tomography. The high stroke rate is reminiscent of early experience with a two-branch system of arch repair (Cook Medical, Bloomington, Ind). As evidenced by later results with the Cook device, increasing familiarity with key parts of the procedure, decreasing instrumentation of the ascending aorta and arch, and the development of a lower-profile device all help to reduce the stroke rate in procedures of this type.2Haulon S. Greenberg R.K. Spear R. Eagleton M. Abraham C. Lioupis C. et al.Global experience with an inner branched arch endograft.J Thorac Cardiovasc Surg. 2014; 148: 1709-1716Abstract Full Text Full Text PDF PubMed Scopus (200) Google Scholar Five patients (56%) in the current study had an endoleak at some point. The authors suggest that “new endoleaks developed” in the postoperative period. I hope not, because a loss of aneurysm exclusion (new endoleak) would call into question the stability of the device and the durability of the repair. More likely, the endoleaks were present from the time of stent graft implantation. After all, intraoperative angiography is not the most sensitive method of endoleak detection. The current short-term data give little indication of long-term device performance. Nevertheless, I expect that long-term follow-up will confirm the durability of the repair, partly because most of the components of the Valiant Mona LSA device have withstood long-term clinical use in other Medtronic products and partly because the combination of a self-expanding branch with a cuff-bearing stent graft has worked well in the thoracoabdominal aorta3Reilly L.M. Rapp J.H. Grenon S.M. Hiramoto J.H. Sobel J. Chuter T.A. Efficacy and durability of endovascular thoracoabdominal aortic aneurysm repair using the caudally directed cuff technique.J Vasc Surg. 2012; 56: 53-64Abstract Full Text Full Text PDF PubMed Scopus (88) Google Scholar and the aortic arch.2Haulon S. Greenberg R.K. Spear R. Eagleton M. Abraham C. Lioupis C. et al.Global experience with an inner branched arch endograft.J Thorac Cardiovasc Surg. 2014; 148: 1709-1716Abstract Full Text Full Text PDF PubMed Scopus (200) Google Scholar If the device proves to be as durable as I predict, and increasing operator experience achieves the hoped for reduction in stroke rate, the Valiant Mona LSA stent graft has a promising future. It might play a role not only in the repair of aneurysms involving the distal aortic arch and descending thoracic aorta but also in type B dissections and aneurysms of the proximal aortic arch. Results of the Valiant Mona LSA early feasibility study for descending thoracic aneurysmsJournal of Vascular SurgeryVol. 62Issue 6PreviewStent graft coverage of the left subclavian artery (LSA) may be required to achieve an adequate landing zone in up to 40% of descending thoracic aneurysms (DTAs). The Valiant Mona LSA Thoracic Stent Graft System (Medtronic, Santa Rosa, Calif) consists of a main stent graft and a branch stent graft designed to maintain LSA patency while diverting circulation through the encroaching aneurysm. Participating in the United States Food and Drug Administration's new Innovation Pathway, this first-in-human, early feasibility study evaluates early clinical experience of the Valiant Mona LSA Stent Graft System in patients with DTAs where the proximal landing zone necessitates LSA coverage. Full-Text PDF Open Archive
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