we describe the first valve - in - valve corevalve transcatheter aortic valve replacement in the st . jude toronto stentless porcine aortic valve in the united states , which enabled this 59-year - old patient with a history of bacterial endocarditis and aortic regurgitation to avoid heart transplant with complete resolution of his severe left ventricular dysfunction . while transcatheter aortic valve replacement ( tavr ) volume has grown substantially worldwide in recent years , our collective experience with transcatheter valve - in - valve placement remains relatively low . the first percutaneous valve - in - valve procedure using the corevalve revalving system for aortic regurgitation in a sorin mitroflow aortic bioprosthesis was reported in 2007 in germany . since then , other case reports of valve - in - valve procedures to treat a failing aortic valve bioprosthesis have been described , but very few in stentless bioprostheses . the global valve - in - valve registry of 202 patients ( mean age 78 years , 53% men ) includes 124 corevalve and 78 edwards sapien valves placed in degenerated bioprosthetic valves for aortic stenosis and/or regurgitation . adverse procedural outcomes included initial device malposition in 15% of cases and ostial coronary obstruction in 4% of cases . results from a series of 27 cases in germany suggest that transfemoral valve - in - valve implantation , regardless of the failure mode of the original valve , is a feasible and safe option even in older , higher risk patients . similar results from smaller numbers of patients from another site in germany   and from israel   have also been reported . we report the first transcatheter corevalve valve - in - valve implantation in a stentless porcine aortic valve in the united states for severe aortic regurgitation . in 1998 , a 47-year - old man developed vague symptoms of shortness of breath and fever while on military service in kuwait . he was diagnosed with and treated for bronchitis at the time . when he returned to the united states , he was evaluated with a transthoracic echocardiogram , which revealed mild aortic regurgitation . he was presumed to have had endocarditis and he was treated and followed up . in 2000 , his symptoms worsened and he underwent aortic valve replacement with a st . , he refused a mechanical valve prosthesis since he wished to avoid anticoagulation so he could continue active military duty . shortly after the procedure , his symptoms resolved and then he was lost to follow - up . he presented twelve years later in the fall of 2012 , at the age of 59 , complaining of progressive exertional dyspnea and chest pain . despite these symptoms , he was still able to exercise about two hours daily , but he noted that this was a substantial decline from his baseline . in december of 2012 , he underwent repeat transthoracic echocardiogram , which showed a moderately thickened and calcified bioprosthetic aortic valve with severe regurgitation . repeat transthoracic echocardiogram in april of 2013 showed a markedly dilated left ventricle with severe global hypokinesis and a left ventricular ejection fraction of 20% . he was gradually transitioned to his oral regimen of lisinopril , furosemide , and carvedilol . however , his severe physical decline and cardiomyopathy prompted consideration of heart transplant rather than redo aortic valve replacement . he was transferred to our institution and evaluated by the heart transplant team , who deemed him an appropriate candidate for transplant . however , before listing , they consulted the interventional cardiology and cardiac surgery team regarding other possible options . although it was unclear whether his left ventricular function would recover even after successful valve - in - valve tavr , the interventional cardiology and cardiac surgery team counseled the patient regarding the possible risks and benefits . with the patient 's consent pre - tavr evaluation included a coronary angiogram , right heart catheterization , and ct of the chest / abdomen / pelvis . right heart catheterization showed a right atrial pressure of 6 mmhg , right ventricular pressure of 50/6 mmhg , and pulmonary arterial pressure of 50/26 mmhg with a mean of 34 mmhg . the pulmonary capillary wedge pressure ( pcwp ) was 27 mmhg , with a blood pressure of 90/50 mmhg , the cardiac output was 3.2 l / min and the cardiac index was 1.9 . the pulmonary vascular resistance was 2.2 woods units and the systemic vascular resistance was 1700 dyn - s / cm . ct showed an aortic annulus of 20.4  29.2 mm with a perimeter of 76.6 mm and an angle of 35.5 ( fig.2 ) . the sinuses of valsalva measured 32.5 , 33.5 , and 35.3 mm at the noncoronary , left , and right coronary cusps , respectively . the ascending aorta measured 36.8  38.8 mm at a level 40 mm above the valve . the inner diameter of the previous stentless valve was 18.2  24.1 mm with an inner circumference of 67.4 mm . the distance from the valve to the right coronary ostium was 16 mm , and the distance from the valve to the left coronary ostium was 14.7 mm . ilio - femoral arterial dimensions bilaterally were all greater than 8.3 mm , without significant calcification or tortuosity . based on these measurements , a femoral approach was planned with the anticipated use of either a 26 or 29 mm corevalve prosthesis . ct image of pre - tavr stentless aortic valve in cross section . for the procedure , an 18f sheath was inserted via surgical cut down in the right femoral artery and the aortic valve was crossed with a 0.35 mm straight wire . a pigtail was advanced over the wire into the left ventricle and baseline hemodynamic measurements were performed . an exchange length pre - shaped lunderquist wire was advanced against the left ventricular apex . after removal of the pigtail catheter , a 26 mm corevalve prosthesis was passed and partially deployed ( fig.3 ) . even with partial deployment , we found that the annulus of the previous stentless valve gripped the corevalve device . any attempt to position the device by pulling back encountered considerable resistance . during this process of repositioning , the partially deployed corevalve , we resheathed the device and removed it . angiographic image of wire / valve angle during first unsuccessful attempt at deployment . partial deployment of the corevalve is demonstrated , with a relatively vertical angle that leans the corevalve against the lesser curvature of the aortic arch . we next attempted to deploy a 29 mm corevalve prosthesis with the plan to deploy the valve at a greater depth because of the asymmetry of the coronary cusps due to the previously described left cusp . again when trying to adjust the depth of the device by pulling back on the valve , we encountered considerable resistance , with subsequent popout of the valve again . we resheathed the valve and removed it . finally , a third corevalve prosthesis ( 26 mm ) was attempted and successful deployment was obtained through a different strategy . instead of allowing the valve to advance across the annulus with subsequent withdrawal to an optimal position , we pushed the wire against the lv apex , and oriented the device using the left coronary cusp as the reference . pushing on the wire resulted in its being oriented against the greater curvature of the aorta ( fig.4 ) . following partial deployment , we noted that the device was relatively deep with respect to the non- and right coronary cusps , but was ideally oriented to the deformed left coronary cusp . as opposed to the first two attempts , this time we simply pushed on the wire and did not pull back on the valve with our usual counter - traction . this maneuver resulted in a more optimal angle across the aortic valve , which better matched the orientation of the stentless valve and allowed for successful deployment ( figs . 5 and 6 ) . the patient had a rapid postprocedure recovery and reported much improved symptoms by the time of discharge . discharge tte showed mild - moderate perivalvular aortic regurgitation ( fig.7 ) and follow - up transthoracic echocardiogram at five months showed a well - seated valve with mild perivalvular aortic regurgitation and complete resolution of his lv function to normal . partial deployment of the corevalve is demonstrated , with a more horizontal angle than the previous attempt , resulting in the corevalve leaning more toward the greater curvature of the aortic arch . transthoracic echocardiogram demonstrating mild - moderate perivalvular leak s / p valve - in - valve deployment . our first experience with a stentless porcine valve - in - valve tavr demonstrated many key issues that are crucial to procedural success : ( 1 ) the importance of sizing for a stentless valve - in - valve procedure , ( 2 ) a different wire technique required in order to successfully deploy a valve - in - valve in the setting of a difficult angle and unusual valve anatomy , and ( 3 ) awareness of the difficulty in pulling back the corevalve prosthesis into position through a previous stentless valve . based on the guidelines for sizing from medtronic , an aortic annulus diameter of 2023 mm should require a 26 mm corevalve prosthesis , an aortic annulus diameter of 2327 mm should require a 29 mm corevalve and a 26 - 29 mm aortic annulus diameter should require a 31 mm corevalve . based on our patient 's aortic annulus perimeter of 76.6 mm , which corresponds to an average diameter of 24.4 mm , the appropriate size corevalve prosthesis should be a 26 mm valve . however , the actual valve dimensions are more elliptical than circular , measuring 20.4  29.2 mm . therefore , we considered that with one dimension as long as 29.2 mm , it might be preferable to use a 29 mm corevalve . while we were ultimately successful in deploying a 26 mm valve , we believe that our success in the end was likely due to a change in wire technique rather than a difference in valve sizing . further experience will be helpful in making optimal sizing decisions . of note , our follow - up echo showed mild aortic insufficiency ; it is possible this may have been decreased with the use of a 29 mm valve . while we have previously deployed numerous valves with very horizontal angles ( not uncommonly 50 or more ) , and although this valve only had an angle of 35.5 per the ct scan , the angle along with the partially amputated left coronary cusp posed a more substantial problem than in any of our prior procedures . our usual technique for positioning the corevalve is to push the stiff wire against the lv apex , while pulling back with counter - traction on the corevalve to provide optimal final positioning after partial deployment . when we tried this method with both the 26 mm and 29 mm corevalve prostheses initially , it did not work . when we finally took the approach of pushing the stiff wire against the lv apex without pulling back on the corevalve , this maneuver allowed the corevalve to lean closer to the greater curvature of the aortic arch , thus sitting more horizontally inside the stentless valve for optimal alignment . a final key lesson for us was that the usual smooth pullback of the corevalve once partially deployed does not work as well when pulling back through a stentless valve . once partially deployed , the annulus of the prosthetic valve grips the corevalve device , making repositioning very difficult . on our first attempt , when we pulled back the corevalve gently across the stentless valve , it unexpectedly popped back across the valve . when we attempted again with a larger prosthesis , after partial deployment , it caught on the stentless valve , making it difficult to pullback . ultimately , enough pulling caused it to pop back across the valve rather than sliding back gradually for completion of deployment . during our last attempt , before partial deployment , we carefully positioned the corevalve with our new wire technique for optimal axis orientation , being careful to not start too low to avoid needing to pull back across the stentless valve . this maneuver successfully allowed for full deployment at the appropriate angle and height without requiring any pullback . successful completion of this procedure supports the idea that stentless valve - in - valve tavr can be a feasible alternative to redo aortic valve surgery in a high- risk patient , if the technical aspects of the procedure can be overcome . in this setting , we recommend careful attention to corevalve size choice , revised aggressive wire technique for angle optimization , and careful initial positioning to avoid the need for repositioning once partially deployed . based on the guidelines for sizing from medtronic , an aortic annulus diameter of 2023 mm should require a 26 mm corevalve prosthesis , an aortic annulus diameter of 2327 mm should require a 29 mm corevalve and a 26 - 29 mm aortic annulus diameter should require a 31 mm corevalve . based on our patient 's aortic annulus perimeter of 76.6 mm , which corresponds to an average diameter of 24.4 mm , the appropriate size corevalve prosthesis should be a 26 mm valve . however , the actual valve dimensions are more elliptical than circular , measuring 20.4  29.2 mm . therefore , we considered that with one dimension as long as 29.2 mm , it might be preferable to use a 29 mm corevalve . while we were ultimately successful in deploying a 26 mm valve , we believe that our success in the end was likely due to a change in wire technique rather than a difference in valve sizing . our follow - up echo showed mild aortic insufficiency ; it is possible this may have been decreased with the use of a 29 mm valve . while we have previously deployed numerous valves with very horizontal angles ( not uncommonly 50 or more ) , and although this valve only had an angle of 35.5 per the ct scan , the angle along with the partially amputated left coronary cusp posed a more substantial problem than in any of our prior procedures . our usual technique for positioning the corevalve is to push the stiff wire against the lv apex , while pulling back with counter - traction on the corevalve to provide optimal final positioning after partial deployment . when we tried this method with both the 26 mm and 29 mm corevalve prostheses initially , it did not work . when we finally took the approach of pushing the stiff wire against the lv apex without pulling back on the corevalve , this maneuver allowed the corevalve to lean closer to the greater curvature of the aortic arch , thus sitting more horizontally inside the stentless valve for optimal alignment . a final key lesson for us was that the usual smooth pullback of the corevalve once partially deployed does not work as well when pulling back through a stentless valve . once partially deployed , the annulus of the prosthetic valve grips the corevalve device , making repositioning very difficult . on our first attempt , when we pulled back the corevalve gently across the stentless valve , it unexpectedly popped back across the valve . when we attempted again with a larger prosthesis , after partial deployment , it caught on the stentless valve , making it difficult to pullback . ultimately , enough pulling caused it to pop back across the valve rather than sliding back gradually for completion of deployment . during our last attempt , before partial deployment , we carefully positioned the corevalve with our new wire technique for optimal axis orientation , being careful to not start too low to avoid needing to pull back across the stentless valve . this maneuver successfully allowed for full deployment at the appropriate angle and height without requiring any pullback . successful completion of this procedure supports the idea that stentless valve - in - valve tavr can be a feasible alternative to redo aortic valve surgery in a high- risk patient , if the technical aspects of the procedure can be overcome . in this setting , we recommend careful attention to corevalve size choice , revised aggressive wire technique for angle optimization , and careful initial positioning to avoid the need for repositioning once partially deployed .
key clinical messagewe describe the first valve - in - valve corevalve transcatheter aortic valve replacement in the st . 
 jude toronto stentless porcine aortic valve in the united states , which enabled this 59-year - old patient with a history of bacterial endocarditis and aortic regurgitation to avoid heart transplant with complete resolution of his severe left ventricular dysfunction .