With the wide acceptance of off-pump bypass procedures,

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1 Twelve-Month Patency With the Proximal Connector Device: A Single Center Prosective Randomized Trial Jörg Kemfert, MD, Ulrich T. Ofermann, MD, Markus Richter, MD, PhD, Torsten Bossert, MD, Friedrich W. Mohr, MD, PhD, and Jan F. Gummert, MD, PhD Deartment of Cardiac Surgery, Heartcenter, University of Leizig, Leizig, Germany ADULT CARDIAC Background. The (Cardica Inc, Redwood City, CA) is an automated system that allows for the clamless anastomosis of vein grafts to the aorta. The intent of this study was to rosectively comare one year graft atency of this system with conventional hand-sewn anastomoses in a rosective, randomized trial. Methods. A total of 99 atients undergoing elective off-um coronary byass surgery were randomized to receive their roximal anastomoses with either the handsewn conventional technique or with the system. Patient follow-u consisted of multislice comuted tomograhic scans erformed at discharge and one year ostoeratively. Results. Three atients had to be converted to on-um due to technical reasons. Fifty-one atients were randomly assigned to the grou and 48 atients to the control grou. In five atients in the control grou severe atherosclerosis of the aorta required cross-over to the use of the device, and in one atient in the grou conversion to a hand-sewn anastomosis. Sequential anastomoses were erformed in 88% of the control grou and 73% of grou grafts. Time needed for comletion of the roximal anastomosis including graft loading was seconds for the grou and seconds for the control grou ( < 0.001). One atient died unrelated to cardiac events due to setic multiorgan failure and one stroke was observed in the control grou. There was a trend toward a lower rate of ostoerative delirium in the grou (11.7% vs 25%, 0.088). Patency at discharge (100% grou vs 97.8% control grou) and after one year (97.8% grou vs 93.7% control grou) were comarable. One atient of the grou died during long-term follow-u as a result of a severe stroke due to cerebrovascular disease. Conclusions. This rosective randomized study demonstrated excellent short and midterm atency in both the hand-sewn and grafts. The system allowed for the raid, safe, and effective creation of a roximal anastomosis without the need to clam the aorta. Based on this study we consider this roduct a valid alternative for roximal anastomosis, esecially in atients with severe aortic disease, to avoid side claming of the aorta. (Ann Thorac Surg 2008;85: ) 2008 by The Society of Thoracic Surgeons With the wide accetance of off-um byass rocedures, cross-claming of the aorta is no longer required to initiate cardiac arrest allowing the creation of distal anastomosis. Therefore, roximal anastomotic devices regained some interest to further minimize maniulation of the aorta. After the first device had been evaluated as early as 1979 [1], a variety of different devices have gained regulatory aroval [2]. The most frequently used one was the St. Jude Symmetry (St Jude Medical Inc, St. Paul, MN) with, according to the manufacturer, more than 80,000 imlants worldwide. However, after initial enthusiasm, reorts of early graft stenoses [3] finally led to the withdrawal of the device in 2004 [4]. Desite the shortcomings of the Symmetry device the otential advantages of roximal anastomotic devices, Acceted for ublication Jan 18, Address corresondence to Dr Kemfert, University of Leizig, Heartcenter, Deartment of Cardiac Surgery, Strümellstr. 39, Leizig, D-04289, Germany; kemfert@web.de. such as avoiding lacement of clams on the aorta, time savings, facilitation of limited access surgery, and standardization of the anastomosis, remain an interesting surgical roosition. The Cardica system (Cardica Inc, Redwood City, CA) was introduced into the Euroean and Jaanese market in 2003 and 2004, resectively. The main differentiating features of the system are that in contrast to the Symmetry device the endothelium of the vein is left untouched during the loading and deloyment rocess. Furthermore, the design of the device minimizes the amount of artificial material exosed to blood, which is seen as one of the key mechanisms affecting long-term graft atency. Finally, in anastomosis there is no metal in the orifice of the graft (Fig 1). The results of two nonrandomized multicenter trials [5, 6] were very encouraging [6]. Excet for one study [7] in which the device was used in only nine atients, this roduct has not been studied in a rosective 2008 by The Society of Thoracic Surgeons /08/$34.00 Published by Elsevier Inc doi: /j.athoracsur

2 ADULT CARDIAC 1580 KEMPFERT ET AL Ann Thorac Surg THE PAS-PORT PROXIMAL CONNECTOR 2008;85: Table 2. Intraoerative Variables Variables Fig 1. Enrollment and crossover. (Pts atients.) randomized trial assessing safety and midterm graft atency. This rosective randomized single center study comares clinical outcome, safety, and midterm graft atency in atients undergoing off-um coronary artery byass grafting (OPCAB) with the device or handsewn roximal anastomosis. Table 1. Patient Demograhics Demograhics EF (%) Age (years) Diabetes mellitus (%) Female gender (%) Body mass index Hyerliidemia (%) Left main disease (%) EuroSCORE (%) Conversion rate to or hand-sewn (%) Oeration time (min) Number of distal anastomoses Sequential grafting (%) Time for roximal anastomoses (seconds) Conversion to on-um (%) Graft flow (ml/min) Material and Methods Study Design After aroval by the local ethics committee of the University of Leizig, and written consent obtained from each atient, 99 atients scheduled for elective coronary artery byass grafting (CABG) were enrolled in this single center study at the Heartcenter, Leizig. From July 2003 to Aril 2005, atients were randomly assigned to receive either the roximal vein graft anastomosis with the device ( grou) or by the conventional hand-sewn technique (hand-sewn grou). For a Pas-Port anastomosis no claming of the aorta was necessary; for the hand-sewn anastomosis standard side claming of the aorta was erformed. Eiaortic ultrasound was not available. Primary endoints were atency at discharge and atency after one year evaluated by multislice comuted tomograhic (CT) scans. The secondary endoints were frequency of neurologic events and other anastomosisrelated adverse events. In accordance with the American Psychiatric Association guidelines, ostoerative delirium was defined as a transient mental syndrome of acute onset characterized by global imairment of cognitive functions, reduced level of consciousness, attentional abnormalities, increased or decreased sychomotor activity, and disordered slee-wake cycle [8, 9]. The diagnosis of delirium was made by hysicians involved in the daily clinical care of atients and was most frequently made while atients were in the intensive care unit. Patients with rolonged delirium or focal neurologic signs underwent comuted tomograhy of the brain to look for evidence of stroke [10]. Stroke atients with delirium were included in the study cohort. Exclusion criteria were age under 70 years or reoerative established need for comlete arterial revascularization, concomitant valve disease, renal failure, history of cerebral vascular accidents, nonelective coronary byass surgery, history of an acute myocardial infarct with elevated troonin levels within two weeks rior to surgery, and a left ventricular ejection fraction (EF) of less than 0.3. Study Poulation Patient demograhics are shown in Table 1 and were comarable. A total number of 99 atients were included; 51 atients were randomized to the grou and 48 to the hand-sewn-grou. Enrollment had to be discontinued in Aril 2005 because the device was temorarily not available in Germany (Guidant Inc. discontinued the distribution). Since the end of 2006 the device can be directly ordered from the manufacturer. Technical Asects The system is a single use device for roximal vein graft anastomosis with a one size couler suitable for grafts ranging from 4 to 6 mm in outside diameter. Loading of the device is accomlished by ulling the graft through the imlant and manually everting the roximal end of the graft over the end of the imlant.

3 Ann Thorac Surg KEMPFERT ET AL 2008;85: THE PAS-PORT PROXIMAL CONNECTOR With the hel of a oke-through tool, the everted vein is firmly attached to the imlant. The loaded device is then laced on the aorta and the roximal anastomosis is erformed by rotating a knob on the deloyment tool. The device creates the aortotomy and laces the imlant in one single motion. The design of the system requires erforming the roximal anastomosis first. The osition of the roximal anastomosis was chosen to avoid any kinking of the graft and it was tried to achieve a 90 degree take off angle according to the recommendation of the device manufacturer. In this study all rocedures were lanned as OPCAB and were erformed according to the routine for coronary surgery in our center by one exerienced senior surgeon. The surgeon was trained in a wet lab with more than ten anastomoses and has clinically erformed more than 20 anastomoses, using the device before beginning the study. There were no occlusions in the early hase. All atients received cloidogrel (75 mg er day) and acetylsalicylic acid (100 mg er day) for six months, generally starting within 24 hours after extubation. Angio-CT To asses graft atency, a four-row multislice siral CT angiograhy with retrosective gating was used. The CT scans were read by a radiologist and cardiologist and the graft was either described as oen or occluded. In case of an occluded graft the atient received an angiogram to confirm the result. Statistical Analysis Statistical analysis was erformed using SPSS statistical software (SPSS v ; SPSS, Inc., Chicago, IL). Continuous data are resented as mean standard error of the mean and categoric data as ercentages. For comarison of categoric data the Pearson 2 test and, for continuous data, the indeendent t test were utilized. Results Perioerative Data Three atients had to be converted electively to on-um due to technical reasons. In all but one case, the left internal mammary artery was anastomosed to the left descending coronary artery. All vein grafts were suitable for the device with a mean diameter of 4.75 mm. Each atient received one roximal vein anastomosis and distal anastomoses were done in a sequential fashion as required. As a result, sequential grafting was Table 3. Discharge Patency Intention to Treat Patency 100% (51/51) 97.8% (44/45) Angio 6 2 CT scan Missing data 0 3 Table 4. Twelve-Months Follow-U Intention to Treat Grou (n 51) Grou (n 47) CT scan comleted 45 (88.2%) 32 (68.1%) No CT scan 6 15 Renal insufficiency 3 8 Refusal of follow-u 2 7 Death 1 0 CT comuted tomograhic erformed in 73% of the grou atients and 88% of the hand-sewn grou atients ( 0.064). In five atients of the hand-sewn grou, the device was used instead of the initially lanned handsewn anastomosis due to reoeratively not recognized severe aortic calcification. One atient in the grou had to be converted to a hand-sewn anastomosis because of a roximal tear of the vein graft during deloyment. In one atient the aortotomy was unsuccessful due to a technical roblem. The anastomosis could successfully be comleted by using a second device. Additional stitches for comlete hemostasis were laced in 13 of the total 55 anastomoses (23%). Time to reare and comlete the roximal anastomosis was significantly shorter in the grou. Time needed for comletion of the roximal anastomosis, including graft loading, was seconds for the grou and seconds for the control grou ( 0.001). There were no statistically significant differences regarding standard intraoerative variables between the grous (Table 2). Postoerative Course Postoerative troonin T levels at 48 hours were comarable ( vs hand-sewn, 0.563). One atient in the hand-sewn-grou suffered a stroke confirmed by CT scan on ostoerative day one. Six (11.7%) atients in the grou and 12 (25%) in the hand-sewn grou resented with ostoerative delirium, resulting in a rolonged stay on intermediate or intensive care units. This trend toward a decreased rate of delirium in the grou failed to reach statistical significance ( 0.088). In one hand-sewn case reoeration for bleeding was necessary (no surgical bleeding) and one atient of the hand-sewn grou develoed, ostoeratively, a low cardiac outut syndrome (extracororeal membrane oxygenation treatment for 14 hours) and was successfully weaned and eventually discharged. There was one in-hosital death in the handsewn-grou due to ostoerative setic multiorgan failure. Discharge Graft Patency Before discharge, atency was evaluated by multislice CT scan. In the grou atency evaluation was erformed by CT scan in 45 and by angiogram in six ADULT CARDIAC

4 ADULT CARDIAC 1582 KEMPFERT ET AL Ann Thorac Surg THE PAS-PORT PROXIMAL CONNECTOR 2008;85: Table 5. Twelve-Month Patency Intention to treat Patency 97.8% (44/45) 93.7% (30/32) Follow-u rate 88.2% (45/51) 68.1% (32/47) cases, resulting in a 100% follow u. All anastomoses in the grou were found to be atent. In the hand-sewn grou, atency evaluation was erformed by CT scan in 43 and by angiogram in two cases. One atient refused to undergo CT scan, one atient died due to setic multiorgan failure, and one atient resented with renal insufficiency thus not allowing angio-ct or angiograhy, resulting in missing data in three atients. One graft was occluded at the distal anastomosis site, but no reintervention was necessary. As shown in Table 3, atency at discharge was 97.8% (44 of 45) and comarable ( not significant) to the grou (100%). In the as-treated analysis, all 55 atients (100%) with imlants and 43 of the 44 atients (97.7%) with hand-sewn roximal anastomosis were found to be atent at discharge. Fig 2. Intraluminal view of a deloyed Symmetry (left) and a PAS- Port device (right). Fig 3. Comuted tomograhic scan of a atent roximal anastomosis (arrow). Twelve-Month Graft Patency At 12 months ostoeratively one atient of the grou has died unrelated to cardiac events (severe stroke on ostoerative day 81). Forty-five of the 50 atients alive in this grou at 12 months returned for CT evaluation (90% comliance). Reasons for missing data were renal insufficiency (n 3) and refusal (n 2) as shown in Table 4. Twelve months ostoertatively, in the PAS- Port-grou, one graft was occluded with the need for angiolasty, resulting in a atency rate of 97.8% (44 of 45). In the hand-sewn grou atient comliance at 12 months was significantly lower. Only 32 of the 47 atients discharged returned for CT evaluation (68.1% comliance). In addition to the one graft that was occluded at discharge, a second vein-graft in another atient was occluded at 12 months but did not require any intervention. Graft atency in the hand-sewn grou was therefore 93.7% (30 of 32). In the as treated analysis, 12 month atency for the -atients was 97.9% (46 of 47) with a comliance of 85.5% (47 of 55) and in the hand-sewn atients 93.3% (28 of 30) with a comliance of 68.2% (30 of 44). Patency for grous defined by intention to treat or by as-treated were not statistically significantly different (Table 5). Comment The average age of atients scheduled for coronary artery byass rocedures has continually been rising over the ast decade and this has been associated with a significant change in the atient risk rofile [11]. In this higher risk suboulation, off-um surgery with avoidance of cross-claming of the aorta, extracororeal circulation, and cardiolegic arrest has demonstrated advantages in terms of a reduction in the incidence of stroke, rolonged resiratory failure, bleeding, transfusions, and intensive care unit and hosital length of stay [12, 13]. To further reduce the risk of cerebral vascular accidents, some surgeons have advocated the use of the no touch technique, in which bilateral mammaries are used with or without a radial artery as a T-graft to revascularize the heart [14]. But as this aroach is considered technically highly demanding, and the use of all arterial grafting in atients with advanced age may not rovide the merits seen in a younger oulation, creation of the roximal anastomosis for vein-grafts with the need for artial claming is still indisensable. The otential for neurologic comlications associated with claming of the aorta had triggered the advent of novel technology that would allow the connection of byass grafts to the aorta without the need for claming. The St. Jude Symmetry device was one of the first roximal anastomotic devices to gain

5 Ann Thorac Surg KEMPFERT ET AL 2008;85: THE PAS-PORT PROXIMAL CONNECTOR Fig 4. Comuted tomograhic scan of the occluded anastomosis (arrow). aroval and after initial enthusiasm reorts of early graft stenosis and increased incidence of major adverse cardiac events (MACEs) aeared in the medical literature. Traverse and colleagues [3] reorted an alarming rate of early stenosis at the connector side shortly after the rocedure, requiring multile reinterventions. Consistent with this reort, Bergsland and colleagues [15] documented a atency rate of only 50% with the Symmetry device after five months by angiograhy and atients treated with the device showed a significant increased incidence of early MACEs after one year [16]. Ultimately, the comany voluntarily withdrew the device from the market in Unfortunately, the results of this early exerience generated a general distrust in novel anastomotic technology in the cardiac surgical community. The goal of this rosective, randomized trial study was therefore to rovide evidence for efficacy of a newer generation roximal anastomotic device, the Cardica system (Fig 2). The results of this study showed that grafts attached with a device to the aorta had similar short and longer term safety and efficacy as grafts attached using the conventional hand-sewn technique. In grafts evaluated by multislice comuted tomograhy the atency at discharge in the grou was 100% (Fig 3) and 97.8% in the hand-sewn grou. At the time of discharge none of the atients in the grou had exerienced a major adverse event such as stroke, death, or need for target vessel revascularization. Twelve months ostoeratively, 45 of the 50 atients in the grou alive returned for CT evaluation and 44 of the 45 grafts evaluated were found to be atent (Fig 4). In the hand-sewn grou 30 of 32 grafts evaluated at 12 months were found to be atent. Overall these atency results comare favorably to those ublished in medical literature [17]. This may be exlained by the fact that all atients in this study were ket on cloidogrel for six months [18]. In addition, a significant roortion of grafts (73% of the and 88% in the hand-sewn atients) 1583 in the study were used as sequential grafts, a variable that is known to increase overall blood flow through the roximal anastomosis [19]. Finally, all anastomoses were erformed by an exerienced senior surgeon. All of these factors may have contributed to the atency observed in this articular study. Stenoses or occlusions were redominantly seen in the Symmetry device within two to nine months after surgery. The resent study demonstrates that the device does not seem to be rone to this longer term comlication. This difference in erformance and outcome may be exlained by a number of factors that differentiate the device from the Symmetry device. In contrast to the Symmetry device the system leaves the endothelium of the vein untouched and minimizes the amount of foreign material exosed to blood. The device resents a larger orifice esecially in smaller vein grafts. Lahtinen and colleagues [7] recently reorted low atency rates for the device in a rather small series with only nine atients in the device grou. They seculated that the theoretical takeoff angle at 90 degrees of the device may have had an imact on atency. This stands in contrast to excellent midterm atency observed in our series with a significantly higher number of atients enrolled. In our earlier series we were able to demonstrate by angiogram that after chest closure the takeoff angle in or hand-sewn anastomoses is not different [6]. Nonetheless, the manufacturer of the device emhasizes in the instructions for use the imortance of lacing the device on the anterior ortion of the aorta for grafts to the right and on the concave surface of the aorta for grafts to the left territory. The avoidance of claming the aorta is seen as one of the key advantages of roximal connector devices in resect to a theoretical imact on neurologic outcome. Thus, embolic load should be decreased when using roximal connector systems; but in two trials the Symmetry device failed to reduce the amount of solid emboli evaluated by transcranial Doler [20] or intraaortic filter [21]. To this day there are no data regarding neurologic outcome with the device. In the current study, the rate of ostoerative delirium was lower in the -grou but failed to reach statistical significance. In addition none of the atients in the grou exerienced a stroke or transitory ischemic attack comared with one atient in the hand-sewn grou with a stroke. Currently the rice may be rohibitive for routine use in many centers but given the otential for reducing neurologic comlications, and maybe a higher atency rate (the study oulation in this study was to small to allow to reach a statistically significant result), the device may be cost effective and therefore may be more frequently used. Further randomized trials are necessary to investigate these issues, articular in high risk subgrous such as atients with advanced aortic disease. Limitations of the resent study are evaluation of atency by multislice CT scans and a significant lower follow-u rate in the hand- ADULT CARDIAC

6 ADULT CARDIAC 1584 KEMPFERT ET AL Ann Thorac Surg THE PAS-PORT PROXIMAL CONNECTOR 2008;85: sewn-grou. Angiogram is seen as the gold standard for assessing atency rates. But, as multislice CT scan is evolving raidly and gaining more and more confidence, several studies reorting excellent sensitivity of almost 100% [22, 23] for severe stenosis and occlusion, esecially when addressing the roximal site. Follow-u rate in the hand-sewn-grou was significantly lower because of a higher rate of renal insufficiency after one year, desite equal distribution reoeratively ( 21.6% vs hand-sewn 25%, 0.686). If creatinine exceeded a cutoff value of more than 2.0 mg/dl and the atient resented without angina (Canadian Cardiovascular Society class 0-1), the scheduled CT scan was cancelled. More atients in the hand-sewn-grou declined follow-u CT scan, feeling well and robably being aware of not having been treated with any new technique. All atients were interviewed by telehone and all atients without CT follow-u were asymtomatic. In summary, one year atency of the device is comarable with the conventional hand-sewn aroach. Based on this exerience we consider this roduct a safe and effective tool, esecially in the field of OPBAB rocedures when using vein grafts and in atients with aortic disease. This study was suorted by a research grant from Cardiac Inc, Redwood City, CA. References 1. Guyton RA, McClenathan JH, Michaelis LL. A mechanical device for sutureless aorta-sahenous vein anastomosis. Ann Thorac Surg 1979;28: Falk V, Gummert JF, Walther T. Anastomotic devices for coronary artery byass grafting. Exert Rev Med Devices 2005;2: Traverse JH, Mooney MR, Pedersen WR, et al. Clinical, angiograhic, and interventional follow-u of atients with aortic-sahenous vein graft connectors. Circulation 2003;108: Maisel WH. A device for roximal anastomosis of autologous coronary vein grafts. Circulation 2005;112: Carrel TP, Eckstein FS, Englberger L, Berdat PA, Schmidli J. Clinical exerience with devices for facilitated anastomoses in coronary artery byass surgery. Ann Thorac Surg 2004;77: Gummert JF, Demertzis S, Matschke K, et al. Six-month angiograhic follow-u of the II clinical trial. Ann Thorac Surg 2006;81: Lahtinen J, Biancari F, Ojala R, et al. Prosective, randomized study on the use of the Cardica aortic connector system in off-um coronary artery byass surgery. Heart Surg Forum 2006;9:E Liowski ZJ. Delirium: acute confusional states. Oxford University Press: Oxford; Diagnostic and statistical manual of mental disorders, 3rd edition revised. Washington, DC: American Psychiatric Association; Edmunds LH Jr, Clark RE, Cohn LE, Grunkemeier GL, Miller DC, Weisel RD. Guidelines for reorting morbidity and mortality after cardiac valvular oerations. J Thorac Cardiovasc Surg 1996;112: Ferguson TB, Hammill BG, Peterson ED, DeLong ER, Groveret FL. A decade of change risk rofiles and outcomes for isolated coronary artery byass grafting rocedures, : a reort from the STS National Database Committee and the Duke Clinical Research Institute. Ann Thorac Surg 2002;73: Hoff SJ, Ball SK, Colthar WH, Glassford DM Jr, Lea JW 4th, Petracek MR. Coronary artery byass in atients 80 years and over: is off-um the oeration of choice? Ann Thorac Surg 2002;74:S Hirose H, Amano A, Takahashi A. Off-um coronary artery byass grafting for elderly atients. Ann Thorac Surg 2001; 72: Lev-Ran O, Braunstein R, Sharony R, et al. No-touch aorta off-um coronary surgery: the effect on stroke. J Thorac Cardiovasc Surg 2005;129: Bergsland J, Hol PK, Lingås PS, et al. Intraoerative and intermediate-term angiograhic results of coronary artery byass surgery with Symmetry roximal anastomotic device. J Thorac Cardiovasc Surg 2004;128: Dewey TM, Crumrine K, Morley AH, et al. First-year outcomes of beating heart coronary artery byass grafting using roximal mechanical connectors. Ann Thorac Surg 2004;77: Goldman S, Zadina K, Moritz T, et al. Long-term atency of sahenous vein and left internal mammary artery grafts after coronary artery byass surgery: results from a Deartment of Veterans Affairs Cooerative Study. J Am Coll Cardiol 2004;44: Gurbuz AT, Zia AA, Vuran AC, Cui H, Aytac A. Postoerative cloidogrel imroves mid-term outcome after off-um coronary artery byass graft surgery: a rosective study. Eur J Cardiothorac Surg 2006;29: Farsak B, Tokmakoglu H, Kandemir O, et al. Angiograhic assessment of sequential and individual coronary artery byass grafting. J Card Surg 2003;18: Skelland M, Bergsland J, Lundblad R, et al. Cerebral microembolization during off-um coronary artery byass surgery with the Symmetry aortic connector device. J Thorac Cardiovasc Surg 2005;130: Martens S, Dietrich M, Herzog C, et al. Automatic connector devices for roximal anastomoses do not decrease embolic debris comared with conventional anastomoses in CABG. Eur J Cardiothorac Surg 2004;25: Song MH, Watanabe T, Nakamura H. Multidetector comuted tomograhy versus coronary angiogram in evaluation of coronary artery byass grafts. Ann Thorac Surg 2005;79: Moore RK, Samson C, MacDonald S, Moynahan C, Groves D, Chester MR. Coronary artery byass graft imaging using ECG-gated multislice comuted tomograhy: comarison with catheter angiograhy. Clin Radiol 2005;60: INVITED COMMENTARY A benefit of off-um coronary artery byass (OPCAB) surgery is reduced need for maniulation of the aorta. However, most OPCAB surgeries are still erformed with artial claming of the aorta and handsewn roximal anastomosis. The develoment of connectors for fastening vein grafts to the aorta without claming was met with excitement by cardiac surgeons. St. Jude Symmetry connectors (St. Jude, Inc, St. Paul, MN) were used extensively after a romising introduction, but controlled angiograhic studies demonstrated an unaccetable occlusion rate [1]. The Leizig grou has conducted a randomized study of atency of grafts erformed with PAS-ort roximal 2008 by The Society of Thoracic Surgeons /08/$34.00 Published by Elsevier Inc doi: /j.athoracsur