• Several centers in Poland began last year to enroll consecutive patients with acute coronary syndrome and culprit lesions that were amenable to BVS treatment. By May they had 1-year follow-up data on 94 BVS recipients, mostly patients with unstable angina or non–ST-elevation MI (NSTEMI) but also several with STEMI. The series had 100% success for BVS delivery and device success, with a 3% rate of major adverse coronary events while the patients remained initially hospitalized. After 12 months the patients had no deaths, three MIs, one target vessel revascularization, and one non–target vessel revascularization. Stent thrombosis occurred in one patient who prematurely stopped DAPT. The series so far has had no need for target-lesion revascularization. The 1-year results "show excellent outcomes. I’m amazed the results have been so good," said Dr. Dariusz Dudek, a cardiologist at University Hospital in Krakow, Poland.
• Interventionalists at two centers in Prague saw 311 consecutive patients with STEMI from December 2012 through the end of April 2014, and among these patients 79 (25%) met the group’s criteria for treatment with BVS. The operators excluded patients with a high likelihood of dying during the 2-3 year period for full BVS disappearance, with a Killip class of III or IV. They also excluded patients with an infarct-related artery less than 2.3 mm in diameter or more than 3.7 mm because of the limited size availability of BVS and because of the dangers from using incorrectly sized BVS. The 79 patients who received a BVS were a third of all patients in the series who received some form of PCI. An analysis presented by Dr. Petr Widimský, professor and head of the department of cardiology at Vinohrady Teaching Hospital in Prague, compared 9-month outcomes for these 79 patients who received BVS and 184 patients from the same series who also had Killip class I or II disease at the time of PCI. The remaining 48 patients from the series had Killip class III or IV disease and were excluded. After 9 months, event-free survival rate was 95% in the BVS recipients and 90% in the patients who received PCI with metallic stents, a nonsignificant difference. In the BVS group, 76 of the 79 patients successfully received a total of 85 BVS. Seventy-two of the 76 who received a BVS had an "ideal" procedural result, with no dissections and achievement of full blood flow through the treated lesion; the other four patients had slightly compromised blood flow after BVS placement. The 76 patients who successfully received a BVS had one death 4 hours after PCI as a result of septal rupture, and another BVS thrombosis 3 days after the patient stopped DAPT. A stroke or transient ischemic attack occurred in three patients. "We conclude that using BVS to treat acute STEMI is feasible and safe, and with currently available BVS sizes can be done in 25%-33% of STEMI patients. Having a 4.0-mm diameter BVS would substantially increase the number of patients we could treat," Dr. Widimský said.
• Cardiologists at one center in Barcelona treated 67 chronic total occlusions (CTO) since BVS became available, 49 of which could be crossed with a guidewire. Of these, the interventionalists could place a BVS in 38 patients; they excluded the other 11 patients because of excessive coronary-artery tortuosity, bifurcated lesions, or inappropriate vessel size. Among the 38 CTO patients who received BVS, three required bail-out PCI with a metallic stent because of a dissection. Average CTO length was 19 mm, and the average total lesion length was 36 mm. At 1-month follow-up, there were no deaths, no MI, no need for additional revascularization, and no BVS thrombosis. The same pattern held among the 33 patients from this group who had 6-months’ follow-up. "These surprising, extremely good results seem too good to be true," said Dr. Antonio Serra, an interventional cardiologist at Hospital Sant Pau in Barcelona. Results from the series so far "show that BVS is extremely feasible and safe for treating complex CTO. We report excellent patency and safety. The results at 6 months were outstanding."
Limits on BVS use
BVS are not for everyone. They get ruled out by substantial tortuosity of the route from the catheterization site to the affected coronary because BVS are stiffer than metallic stents and less amenable to pass through a winding arterial route. Patients need to be good candidates to remain on DAPT for at least 12 months, and the target-vessel diameter cannot veer too far from the currently available BVS diameters of 2.5, 3.0, or 3.5 mm. In most centers, these and other exclusion criteria usually rule out 75%-85% of patients, said several experienced BVS interventionalists at the meeting.
"I want patients who are healthy enough so they stay on DAPT. A BVS is not where you try 3 or 6 months of DAPT," said Dr. van Geuns. He also said that he would not use BVS for treating venous grafts, nor for in-stent restenosis because the existing metal likely would prevent late-lumen enlargement. And in some patients BVS cannot reach the lesion site despite aggressive predilation and vessel preparation.
"We’ve seen increasing breadth of use in the real world. It’s not yet true 100% all-comers, because appropriately people are learning where to use this technology," commented Dr. Stone.
"Our data represent a bias because it is not 100% of our patient population. They are the patients whom we think it is possible to implant a BVS," Dr. Tamburino said.
BVS "technology is not forgiving," Dr. van Guens pointed out. "If you leave a small lumen you will get a small lumen, and that can cause flow disturbances and perhaps a thrombus. Sometimes we are too eager with this technology. I think we can get to 100% in the future, but we should go slow because we are not there yet." He added that the number of BVS recipients and the rate of stent thrombosis were so far too small to allow meaningful analysis of which BVS recipients faced the greatest risk of stent thrombosis. Possible factors include inadequate post dilitation of the BVS, overexpansion of a BVS, and premature halt of DAPT.
"BVS is now feasible to use for every case" as long as the target vessel is no more than 10% smaller than the available BVS, Dr. Julinda Mehilli, an interventional cardiologist at the German Heart Center in Munich, said in a talk at the meeting. Preferred locations are long lesions in distal segments. Operators should be cautious using BVS to treat bifurcations, arteries with pronounced tortuosity, or arteries with moderate to severe calcification. When two BVS are needed in tandem, they should be placed as close to edge to edge as possible. She also stressed the need for systematic attention to every phase of BVS preparation and delivery, starting from selecting the appropriate BVS diameter to match the target vessel, predilation of the lesion and vessel and removal of calcium, gradual inflation of the BVS itself, and then followed by post dilitation of the BVS with a noncompliant balloon, ideally for at least 20 seconds.
"Now that we have BVS, it is the device of choice for chronic total occlusions because long term there is healing of the vessel walls when we use BVS. We often see long-term malopposition of stent struts in chronic total occlusions. With BVS the scaffold will disappear," eliminating the malopposition risk, Dr. Mehilli said.
Dr. Stone had no relevant disclosures, but he is lead investigator for an ongoing trial studying Abbot Vascular’s Absorb BVS. Dr. Serruys, Dr. Eeckhout, Dr. Schmitz, Dr. Dudek, and Dr. Serra had no disclosures. Dr. Tamburino is a consultant to Abbott Vascular and three other companies. Dr. Simonton is an employee of Abbott Vascular. Dr. van Geuns has received honoraria and research support from Abbott Vascular and other companies. Dr. Widimský has received honoraria from Abbott Vascular and other companies. Dr. Mehilli has received lecture fees from Abbott Vascular and other companies.
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