Abstract
Two cases of acute left main (LM) obstruction complicating transcatheter aortic valve replacement (TAVR) and their management are reported. TAVR with a self-expandable transcatheter aortic prosthesis was performed for treating severe aortic stenosis with small aortic root and severe aortic regurgitation of a degenerated stentless bioprosthesis, respectively. Left main coronary obstruction occurred at a different time from the index procedure. A novel stent-based angioplasty treatment, denominated “the tunnel technique,” was successfully applied in both cases and herein described.
1
Introduction
Transcatheter aortic valve replacement (TAVR) has emerged as a viable alternative to surgical aortic valve replacement for patients with severe symptomatic aortic stenosis considered at unacceptable surgical risk. A number of large multicenter studies have demonstrated the efficacy and safety of TAVR in high-risk patient cohort. Coronary ostia involvement is an uncommon complication after TAVR, and it has been reported after balloon expandable valve (Edwards SAPIEN) implantation . Only one case has been previously described following the implantation of a self-expandable transcatheter prosthesis (CoreValve, Medtronic, USA) with unfavourable outcome . We report two cases of acute left main (LM) coronary obstruction after a CoreValve implantation and their management by means of a novel stent-based angioplasty procedure able to restore ostial patency and coronary perfusion.
2
Case reports
2.1
Case 1
An 86-year-old woman was scheduled for TAVR because of high-risk surgical aortic valve replacement (Logistic euroSCORE 45%) and severe aortic stenosis associated with severe left ventricular dysfunction. She had undergone balloon aortic valvuloplasty as a bridge procedure to TAVR. The patient had a “small” aortic root anatomy with an annular size of 20 mm at transesophageal echocardiography. CT scan measures were 23×18 mm for the annulus, 27 mm for the sinus of Valsalva, and 20 mm for the sino-tubular junction. The coronary artery take off was 11 mm, and the length of the left leaflet was 11 mm. All aortic valve leaflets appeared highly calcified at CT scan. A 26-mm CoreValve implantation was carried out. The postimplantation angiogram showed a bulky calcium mass in the noncoronary and left sinuses of Valsalva with coronary artery flow preserved and a normal electrocardiogram ( Fig. 1 A and B). The day after, the patient experienced acute chest pain during early mobilization. Diffuse ST modifications at electrocardiogram and a worsening of regional and global left ventricular function at the echocardiogram were detected. The coronary angiogram showed a partial obstruction of the LM by the bulky calcium of the native valve leaflet. A 6F extra back-up (EBU) 3.5 guiding catheter (Launcher, Medtronic, USA) was used to cannulate the LM after an unsuccessful use of several guiding catheters. Then, after predilatation, a bare metal stent (BMS) 4×15 mm was implanted in the LM landing into the CoreValve’s frame. An evident waist during balloon inflation was detected, and intravascular ultrasound (IVUS) showed an incomplete expansion of the stent ( Fig. 2 ). Therefore, a second BMS 5×13 mm, at 20 atm, (stent in stent) was deployed with a correct expansion at IVUS control ( Fig. 3 ). The following hospital stay was uneventful. A patency of the stent without restenosis was detected during the angiographic follow-up performed at the fourth month from the index procedure. At 1 year follow-up, no major cardiovascular event occurred; the patient was in functional class NYHA II with a complete recovery of left ventricular function and a normal valvular function at echocardiography.
2.2
Case 2
An 82-year-old male had severe aortic regurgitation due to degenerated stentless bioprosthesis (CryoLife-O’Brien size n.25) caused by a prolapse of the noncoronary cups. He had, at the baseline aortic root angiography and at the CT scan, a large sinus of Valsalva (33 mm) and a 10-mm distance between the LM and aortic annulus ( Fig. 4 ). The patient underwent TAVR with CoreValve 29 mm. Immediately after the valve implantation, the patient had chest pain with hypotension (systolic blood pressure of 80 mmHg). The electrocardiogram was not diagnostic because of a permanent pacemaker-induced rhythm, while a worsening of regional and global left ventricular function at the echocardiogram was shown. There was no residual aortic regurgitation, and the aortography showed a diaphragmatic obstruction of the LM ( Fig. 5 A ). An intra-aortic balloon counterpulsation was quickly placed. After the cannulation of the LM with a 6F EBU 3.5 guiding catheter (Launcher), an improvement of the flow and a regression of the chest pain were observed. In order to better investigate the characteristics of the LM obstruction, an IVUS was performed with evidence of a membrane obstructing the LM entry ( Fig. 5 B). A BMS 5×13 mm, at 24 atm, between the proximal part of the LM and the left sinus, outside of the valve’s frame, was then deployed with a good final angiographic result ( Fig. 6 ). Shortly after the guiding catheter withdrawal, a sudden recurrence of chest pain occurred which was associated with a new decline in LM blood flow at angiogram. On the assumption that the guiding catheter could have prevented the bioprosthetic leaflet occlusion of the LM ostium, a second BMS (5×13 mm) was positioned backwards ( Fig. 7 ) with the aim to create a “tunnel” between the CoreValve’s frame and the LM. After the second implantation, a normal antegrade flow was restored ( Fig. 8 ) with regression of electrocardiogram abnormalities and chest pain. The following hospital stay was uneventful. An angiographic follow-up was performed at the fourth month from the index procedure showing the patency of the stent without restenosis. At 1 year follow-up, no major cardiovascular event occurred and the patient was in functional class NYHA II with a normal prosthetic valve function at echocardiography.
