LATE FOLLOWUP OF A SINGLE CENTER EXPERIENCE WITH A NOVEL DEVICE FOR APICOAORTIC CONDUIT IMPLANTATION
Sarnoff‘s first animal studies concerning the feasibility of the implantation of apico-aortic conduit were published in 1955 [1-5]. From its birth this operation not frequently used because of bleeding complications and lack of adequate instruments to perform ventricular coring. The introduction of an automated system of coring and delivery of ventricular connector (Correx Aortic Valve Bypass® AVB) allows to perform this operation with reduced risk of bleeding and with the chance to avoid cardiopulmonary bypass due to the chance to perform the procedure on a beating heart . In addition, in the last 6 cases of our experience, we took the advantage to use a suture automated fastener device (COR-KNOT®, LSI solutions) reducing operative time, bleeding and standardizing the surgical procedure. We report our experience with the use of Correx AVB® for the treatment of patients with severe aortic valve stenosis denied for conventional aortic valve replacement focusing on long-term clinical and echocardiographic follow-up and efficacy and safety of COR-KNOT® fastener system as well.
MATERIAL & METHODS
From March 2012 to April 2015, 21 patients were submitted to aortic-valve bypass using the new device to treat a severe aortic valve stenosis. The Correx AVB® shows 2 components: a valved conduit incorporating a stentless bioprosthesis to be anastomosed on the descending thoracic aorta and a 18 mm ventricular connector to be inserted through the apex of the left ventricle using an automated coring and deploying device (Figure 1). In 6 patients we use COR-KNOT® suture fastener system. We considered as indications any preoperative clinical or anatomical condition, often not reported in standard risk calulators, that could represent a risk of serious complications either for candidacy to standard aortic valve replacement or for percutaneous aortic valve implantation. In addition we used Logistic EuroSCORE and STS risk calculator to provide an objective quantification of in-hospital mortality and morbidity. Statistical analysis was performed using non-parametric analysis and survival probability was calculated according to Kaplan-Meier analysis.
Patients median age was 78 years (25th-75th perc: 71-81,3); 60% were female. Median ejection fraction (%EF) was 55 (25th-75th perc: 46,7-60,5); preoperative NYHA class was 3 (25th-75th perc: 2-3); Logistic EUROscore and STS score risk of morbidity/mortality were 11,29% (25th-75th perc: 7,8-20,4) and 23,24% (25th-75th perc: 19,3-27,8) respectively. All patients received AVB through a mid-lateral thoracotomy. All the operation were performed on a beating heart. In two patient we planned to use ECMO to support lung function. In 2 patients a concomitant off- pump left internal thoracic artery (LITA) to left anterior descending (LAD) stenosis was performed, one of them receiving a lung cancer exeresis during the same procedure . In the last 6 patients (July 2014-April 2015) we tied all U-stitches with COR-KNOT® automated fastener either on aortic and on ventricular side (Fig. 2).
No intraoperative death was recorded. In-hospital mortality was 19% (5 pts): 2 for multi-organ dysfunction, 1 for haemorrhagic shock due to iatrogenic lesion of liver during thoracentesis, 1 for acute gastrointestinal bleeding and 1 for Klebsiella Pneumonie sepsis. Median intubation time and ICU length of stay were respectively 17,5 hours (25th-75th perc: 16-20,7) and 42 hours (25th-75th perc: 23-59,5). Median number of red blood cells package transfusion for each patient was 3 (25th-75th perc:2-5). Postoperative ward length of stay was 13,5 days (25th-75th perc: 7,7-18).
Operative time reduction with the use of COR-KNOT automated fastener
Median operative time in the fist series of patients with hand tied sutures was 217 minutes (25th-75th perc: 198-271) compared to 155 minutes (25th-75th perc: 136-197) of COR-KNOT® group (p: 0,026) (Fig. 3). Moreover, skin incision was significantly shorter in COR-KNOT® group (15 cm vs 20 cm; p=0,02). All patients in COR-KNOT® group were submitted to postoperative angio-CT scan without evidence of any leak or LV pseudoaneurysm.
Late clinical follow-up
Follow-up of 13 out-of-hospital survivors was 100% completed. Median follow-up was 850 days (25th-75th perc: 293-993). The longer follow-up was 1161 days. Three patients died during the follow-up (23%) patients: 1 of necrotic-haemorrhagic pancreatitis, 1 of liver carcinoma and 1 of retroperitoneal haemorrhage. Among survivors 12 were in NYHA class I and 1 in NYHA class III (Low %EF before AVB implantation in NYHA class IV). Kaplan-Meier estimated survival at 1161 days was 80% ± 10% (Fig 3).
2D-Echocardiography with Color-Flow Mapping was perfomed after a median of 947 days (25th-75th perc: 583-1030). Median %EF was 60% (25th-75th perc: 57,5-60). Peak and mean aortic valve gradients were respectively 32 mmHg (25th-75th perc: 22-32) and 20 mmHg (25th-75th perc: 14-20). In two patients a preoperative severe mitral regurgitation, decreased to mild at follow-up.
To the best of our knowledge this is the largest experience in the use of CORREX AVB®. Our results suggest that AVB could be a feasible alternative to conventional AVR in selected patients with both good clinical and echocardiographic outcome at follow-up with significant reduction of gradients across native aortic valve so confirming the results previously reported . The use of COR-KNOT® automated fastener significantly contributed to operative time reduction, to make easier the conduit implantation at the level of descending aorta, helping to reduce the length of skin incision. In our experience the implementation of this new device led towards a lesser invasive approach for CORREX® AVB implantation.
1. Sarnoff SJ,Donovan TJ,Case RB.The surgical relief of aortic stenosis by means of apical-aortic valvular anastomosis. Circulation. 1955 Apr;11(4):564-75.
2. Cooley DA, Norman JC, Reul GJ Jr, Kidd JN, Nihill MR.Surgical treatment of left ventricular outflow tract obstruction with apico-aortic valved conduit. Surgery. 1976 Dec;80(6):674-80.
3. Brown JW, Girod DA, Hurwitz RA, Caldwell RL, Rocchini AP, Behrendt DM, Kirsh MM. Apico-aortic valved conduits for complex left ventricular outflow obstruction: technical considerations and current status. Ann Thorac Surg. 1984 Aug;38(2):162-8.
4. Lund JT, Jensen MB, Arendrup H, Ihlemann N. Aortic valve bypass: experience from Denmark. Interact Cardiovasc Thorac Surg. 2013 Jul;17(1):79-83.
5. Brown JW, Kirsh MM. Technique for insertion of apicoaortic conduit. J Thorac Cardiovasc Surg. 1978 Jul;76(1):90-2.
6. Gammie JS, Brown JW, Crunkleton JA, Bittle GJ, Stauffer CE, Liepert AG, Ghoreishi M. An automated coring and apical connector insertion device facilitates aortic valve bypass (apicoaortic conduit) surgery: preclinical experience in a chronic ovine model. J Heart Valve Dis. 2012 Jul;21(4):494-501.
7. Kaplan EL, Meier P. Nonparametric estimation from incomplete observations. Journal of the American Statistical Association. 1958;53:457–81.
8. Di Giammarco G, Canosa C, Foschi M, Mucilli F, Marinelli D, Nuzzo N, Testa N.Novel apical coring device for apicoaortic conduit insertion to treat off-pump aortic stenosis, coronary disease, and lung cancer. Innovations (Phila). 2015 Mar-Apr;10(2):138-41.
9. Gabriele Di Giammarco, MD, Massimiliano Foschi, MD, Daniele Marinelli, MD, Carlo Canosa, MD Mid-term results of off-pump aortic valve bypass using a novel automated device in severe aortic valve stenosis. ISMICS meeting 2014 , 28-31 May 2014, BOSTON, USA.