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Paper text:
the revival of off - pump cardiac surgery and the exploration of less invasive techniques for coronary artery bypass grafting , have lead to an increasing technical difficulty , as compared to conventional surgery using cardiopulmonary bypass .
the moving target vessel in off - pump coronary artery bypass surgery , as well as the increasingly limited space in minimally invasive cardiac surgery were not convenient to many surgeons , a fact that lead many surgeons to deprive their patients the potential benefits of these techniques .   since the 1950 s
, surgeons have attempted to make the anastomotic procedure less cumbersome and less time consuming .
many creative ideas and devices were made , but for many different reasons , they eventually faded away . since then , hand - sewn anastomoses have been the standard of care in coronary artery bypass grafting . today , with the obvious need for a facilitated and fast coronary anastomosis , interest in these anastomotic devices has been re - awakened .
the exact geometry , physiology and dynamics of the perfect anastomosis have thus been studied , in an attempt to provide an understanding of reasons behind anastomosis and graft failure after coronary artery bypass surgery , and eventually design the best performing device .
these devices would allow for a faster , more accurate and a more reproducible coronary anastomosis using minimally invasive techniques . also , due to a short learning curve , the standardization of percutaneous devices would allow much more surgeons to more widely adopt less invasive techniques . in summary
, we see anastomotic devices as a solution to the technical challenges surgeons encounter with minimally invasive coronary artery bypass grafting .
in what is believed to be the first soviet contribution to american medical literature , pavel androsov described the first vascular anastomotic device in 1956 .
after world war ii , androsov favored the use of his device over vascular ligation , citing reasons that would be still valid in our current day .
four years later , the first human coronary artery bypass ( cab ) procedure took place , reported by robert goetz at albert einstein university .
interestingly , this first attempt ( right internal mammary artery to right coronary artery ) was done using a tantalum ring anastomotic device with circumferential sutures . in leningrad in 1964 , vasilii kolesov performed the first hand - sewn clinical cab , citing goetz work as a predecessor .
three years later , he performed the first , and for a long time the only , coronary anastomosis using a vascular stapler , and three years later , the patient remained free of symptoms .
many anastomotic devices were designed and produced in the 1960 s , but the advent of cardiopulmonary bypass ( cpb ) and its wide adoption made hand suturing on a motionless heart a more convenient option to surgeons .
vascular connector devices eventually faded away from the interest of surgeons , and hence manufacturers , and for a long time , the well established cab technique remained - efficient but technically stagnant . in the 1990 s , against the background of significant morbidities associated with the use of cpb and myocardial ischemic arrest , interest in off - pump cab surgery ( op - cab ) was reawakened . this revival of interest re - established the same circumstances that brought interest to vascular connectors 40 years earlier .
not much later , the development of minimally invasive cardiac surgery - cab ( mics - cab ) and totally endoscopic cab ( tecab ) made the hand suturing technique even more challenging and excessively time consuming , making connector devices , once again , an attractive option .  
although graft failure is probably multi - factorial , technical error still shares a good deal in this failure .
anastomotic connector devices decrease the error in hitting a moving target ( opcab ) , as well as facilitate graft anastomoses in a restricted space ( mics - cab ) .
the need for an aortic cross clamp has been achieved in opcab , but the proximal anastomoses still mandated a partial clamp application .
connector devices allow performing proximal anastomoses with minimal aortic manipulation , and thus improve neurological outcomes .
also , the supposedly reduced time needed to complete an anastomosis using a connector device would allow for less hemodynamic instability , when grafting posterior vessels off - pump , as well as allow for a shorter clamp time when using cpb and ischemic arrest , and thus would be associated with less morbidity and mortality .  
more than 60 connector devices have been designed and produced by several manufacturers for coronary bypass surgery alone , and due to different outcomes and economic reasons , only a few of them came to fruition .
a perfect connector device should display a number of geometric , physiological , technical and outcome characteristics , in a cost effective context .
these characteristics would ensure patency rates that are at least , and adverse event rates that are at most , equal to standard hand suturing technique .
an understanding of how this can be , invites an understanding of how failure happens .
altering flow dynamics and disrupting endothelial continuity may lead to thrombosis , intimal hyperplasia or both .
the blood exposed non - intimal surface ( benis ) , whether it be the media , adventitia or foreign material ( suture , metal , etc ) has been directly correlated to thrombosis .
this is the reason why two distal connector devices are no longer available ; the graft connector of jomed ( jomed inernational ab , helsingborg , sweden ) and the magnetic vascular positioner mvp ( ventrica inc , fremont , ca ) .
this was particularly relevant with the spyder ( medtronic inc , minneapolis , mn ) , probably due to the lack of support from a connecting ring .
intimal hyperplasia for less than understood reasons was a main issue with the symmetry aortic connector system ( st .
paul , mn ) , leading to a graft patency of 50% at 3 - 5 months angiographic follow - up .
despite the early enthusiasm with this device , it was abandoned by sjm due to what the authors described as an unacceptably low intermediate result .
excessive graft manipulation while loading on the connector is very likely to cause endothelial denudation , with subsequent thrombosis . also , what seems to be inconvenient to many surgeons , is that most proximal connecting devices require that the proximal anastomoses be constructed before the distal ones .
most proximal connectors have a graft take - off angle from the aorta approaching 90. these two issues require careful planning of graft length and position to avoid graft kinking and excessive wall stress . the pas - port device ( cardica inc , redwood , ca ) overcomes the issue of kinking by having a low implant body height . in summary , a perfect connector device should provide anastomoses with the least possible benis , the largest possible orifice area that is supported and compliant , a least possible chance to develop intimal hyperplasia , and should be  surgeon friendly  ( graft loading and deployment that are easy , fast and reproducible ) .
in addition , it should allow for graft anastomosis at all angles and in a confined space , and in proximal connectors , with minimal aortic manipulation .
of extreme importance , is the ease of recovery after unsuccessful deployment , leaving undamaged vessel edges that are still sewable . all these characters should interplay to make this  perfect  device display results that are non - inferior to standard technique .
it is however , beyond any doubt , that internal mammary arteries ( i m a ) have a superior patency profile compared to any other graft material . in some reports , the i m a patency after 10 years was better than saphenous venous graft ( svg ) patency after 1 year .
for this reason , comparing hand - sewn anastomoses to connector device anastomoses is more convenient using venous grafts , giving connector devices a potential to display patency superiority over a relatively short time frame .
this is under investigation in the magic trial ( multi - center assessment of grafts in coronaries : long - term evaluation of the c - port device ) .
patency rates of svgs to non - lad vessels have also varied considerably , however , the widely accepted average is 85% patency at 6 months , and 80% at one year .
the cited patency rates over the past 20 years have shown a gradual decline in patency rates , which may partially be attributed to the more advanced vessel disease presenting to surgeons , in the presence of percutaneous coronary interventions as a first line . in general , the quality of anastomosis tends to affect early patency rates , while late patency rates are more governed by progressing atherosclerotic disease .
this made most studies satisfied with comparing hand - sewn anastomosis to ones done by a connector device , only for a period of 6 months .
they can be generally classified to self - expanding , mechanically - expanding and non - expanding devices .
the corlink device ( bypass ltd , herzelia , israel ) utilized a nitinol self - expanding mechanism .   mechanically expanding devices
paul , mn ) , the pas - port system ( cardica inc , redwood , ca ) , the automated anastomotic distal device ( aadd , bypass ltd , herzelia , israel ) and the spyder device ( medtronic inc , minneapolis , mn ) , all rely on the same concept of mechanical expansion .
creative ideas have been implemented in other non - expanding devices to perform the task .
paul , mn ) , and the magnetic vascular positioner ( mvp , ventrica inc , fremont , ca ) are examples of the non - expanding group . out of the - more than fifty - designs , only 2 devices for proximal anastomosis , and one device for distal anastomosis earned the food and drug administration ( fda ) approval .
this lack of support might be behind the high rates of stenosis ( 52.7% ) after 6 months .
on the other hand , the pas - port utilizes connecting ring - supported stainless steel tines .
worth noting , the supporting ring in the pas - port lies outside the vessel , with no blood contact thus minimizing benis , in contrast to the earlier symmetry device .
the epic trial was a randomized controlled , prospective , multi - center trial that evaluated the pas - port device .
comparing patency rates at 9 months , and comparing mean aortic take - off angles both showed no statistical significance between the device constructed anastomoses and the hand - sewn ones .
the fda approved connector device for distal anastomosis comes from the same manufacturer ; the c - port .
it is available in slightly different modifications , with versions allowing for port access coronary anastomosis .
on the target coronary vessel , proximal to the area of the anticipated anastomosis , a small stab is made , the anvil of the device is passed through the stab and the device is deployed , forming an end - to - side anastomosis .
a previously placed purse string suture at the site of the stab should not compromise the proximal coronary lumen .
matschke and colleagues   reported a patency of 96% , with a fitzgibbon a patency in 91.7% , 6 months after using the c - port .
patency rates using the c - port and standard techniques lacked any difference as reported by suyker and colleagues .  
minimally invasive cardiac surgery ( mics ) saves the patient a number of morbidities associated with classical sternotomies . with less surgical trauma
, mics is associated with significantly less pain , less transfusion requirements , a shorter hospital stay , a faster recovery , reduced costs , enhanced cosmesis and a consistently higher patient satisfaction . minimally invasive cardiac surgery - cab and tecab proved to be safe and feasible for multivessel coronary disease . with the expanding reach of percutaneous interventions
, surgeons should be striving for less invasive techniques that would be more appealing to the patients . despite these facts ,
mics - cab does not seem to be gaining the expected popularity among cardiac surgeons .
reasons behind this reluctance are different with different surgeons , but all revolve around two main factors ; technical difficulty and prolonged time
the two cardica connector devices ( pas - port for proximal and c - port for distal anastomoses ) have a very favorable profile concerning these exact two factors . after a relatively short learning curve with these devices ,
the surgeon should be able to perform minimally invasive cab anastomoses with more ease and in less time .
balkhy and colleagues   published a review of 120 cases integrating these connector devices with robotics towards a totally endoscopic beating heart approach , and results were impressing . at our institution , we performed 132 cases of mics - cab since august 2008 , 52% of which were multi - vessel disease .
since september 2010 , we performed 22 cases of mics - cab using connector devices , all using the pas - port of the proximal anastomoses , and the c - port for the distal ones .
our experience with connector devices in mics - cab is favorable , with a very reasonable learning curve .
we believe a wider scale adoption of connector devices would allow more surgeons to shift their practice towards less invasive cardiac surgeries .
if this was to occur , a much larger number of patients will be offered the benefits of these techniques . redefining the standard of care in cab surgeries might well compete with newer percutaneous interventions for best results and patient convenience .
the revival of off - pump cardiac surgery and the exploration of less invasive techniques for coronary artery bypass grafting , have lead to an increasing technical difficulty , as compared to conventional surgery using cardiopulmonary bypass . 
 the moving target vessel in off - pump coronary artery bypass surgery , as well as the increasingly limited space in minimally invasive cardiac surgery were not convenient to many surgeons , a fact that lead many surgeons to deprive their patients the potential benefits of these techniques . since the 1950 s 
 , surgeons have attempted to make the anastomotic procedure less cumbersome and less time consuming . 
 many creative ideas and devices were made , but for many different reasons , they eventually faded away . since then , hand - sewn anastomoses have been the standard of care in coronary artery bypass grafting . today , with the obvious need for a facilitated and fast coronary anastomosis , interest in these anastomotic devices has been re - awakened . 
 the exact geometry , physiology and dynamics of the perfect anastomosis have thus been studied , in an attempt to provide an understanding of reasons behind anastomosis and graft failure after coronary artery bypass surgery , and eventually design the best performing device . 
 these devices would allow for a faster , more accurate and a more reproducible coronary anastomosis using minimally invasive techniques . also , due to a short learning curve , the standardization of percutaneous devices would allow much more surgeons to more widely adopt less invasive techniques . in summary 
 , we see anastomotic devices as a solution to the technical challenges surgeons encounter with minimally invasive coronary artery bypass grafting .