Computer-enhanced mitral valve surgery: toward a total endoscopic procedure.

The aim of the study was to develop a computer-enhanced, video-assisted approach for mitral valve repair as a potential step toward a complete endoscopic procedure. In 10 patients with nonischemic mitral valve insufficiency, computer-enhanced telemetric mitral valve repair using the Intuitive surgical telemanipulation system was performed. A femorofemoral bypass was initiated using Port-Access (Heartport, Redwood City, CA) cannulation. A small minithoracotomy was made in the right 4th intercostal space, and a custom-made rib retractor was placed. The pericardium was opened manually, and four traction stay sutures were placed to enhance exposure. After endoaortic balloon clamping, the left atrium was opened and stabilized. The end-effectors were placed in the left atrium through two ports (3rd ICS and 6th ICS, midaxillary line). A 30 degrees three-dimensional (3D)-videoscope angled up was placed through the incision. Mitral valve repair was then performed remotely from the surgical console. This included inspection of the valve, leaflet resection, leaflet repair, and ring implantation. After completion of the repair and testing of the valve, the end effectors were withdrawn, and the left atrium was closed manually using standard endoscopic instruments (Heartport). In all but 1 patient, successful repair, including quadrangular resection, chordal shortening, Whooler-plasty, and Alfieri-plasty, could be accomplished using the computer-enhanced telemanipulation system. A partial ring was implanted in 6 patients and a complete ring was implanted in 3 patients, respectively. Time for surgery, CPB, and clamp time were 170 to 330 minutes (median, 185 minutes), 140 to 220 minutes (median, 149 minutes), and 78 to 133 minutes (median, 94 minutes), respectively. In one patient, intraoperative transesophageal echocardiography (TEE) showed insufficient repair, a second surgery was performed via an enlarged left thoracotomy. One patient with recurrent mitral insufficiency had to have a second surgery on postoperative day 3 for a torn-out ring. Median time of hospitalization was 8 days. At 3 months follow-up (completed in 7 patients), all patients had improved clinically. Computer-enhanced mitral valve repair is feasible and can be performed with good functional results. The telemanipulation system offers the potential for true endoscopic mitral valve repair. However, surgical time is prolonged, and a learning curve has to be overcome.     

Experimental off-pump coronary bypass using a robotic telemanipulation system.

We hypothesized that a high-quality anastomosis between the left internal thoracic artery and the left anterior descending coronary artery could be constructed off-pump using a 4-degrees-of-freedom robotic telemanipulation system, endoscopic myocardial stabilization, and two-dimensional visualization. Nine swine were used. Three ports were created on the left chest for the endoscope and the two robotic arms, and another port was created on the right chest for the endostabilizer. Quality of anastomosis was assessed by angiography, analysis of flow, survival after proximal coronary ligation, and histopathology. All nine anastomoses were completed successfully in 22 +/- 3.6 minutes without the need for repair stitches. Left internal thoracic artery flow was 21.6 +/- 2.5 ml/min with diastolic dominant pattern. Eight animals (89%) survived for 60 minutes with the proximal left anterior descending coronary ligated. Angiographic patency was 100% with Fitzgibbon grade A in all. Histopathology of the anastomosis demonstrated minor changes in the integrity of the endothelium and the internal elastic lamina and absence of medial necrosis. We have demonstrated in our robotic off-pump coronary bypass model that a high-quality anastomosis can be constructed between the left internal thoracic artery and the left anterior descending coronary artery. These results support continued research towards robotic endoscopic off-pump CABG.     

Computer-enhanced "robotic" cardiac surgery: experience in 148 patients

OBJECTIVE: A computer-enhanced instrumentation system was used in 148 patients to minimize access in cardiac surgical procedures. METHODS: The da Vinci telemanipulation system (Intuitive Surgical, Mountain View, Calif) provides a high-resolution 3-dimensional videoscopic image and allows remote, tremor-free, and scaled control of endoscopic surgical instruments with 6 degrees of freedom. By April 2000, the system had been used in 131 patients for coronary artery bypass grafting and 17 patients for mitral valve repair. In the coronary bypass group, the system was used in one of three ways: (1) to take down the internal thoracic artery followed by a minimally invasive direct coronary bypass procedure (n = 81); (2) to perform the anastomosis between the internal thoracic artery and the left anterior descending coronary artery in standard-sternotomy coronary bypass (n = 15); or (3) for total endoscopic coronary artery bypass grafting to anastomose the left internal thoracic artery to the left anterior descending on the arrested heart (n = 27) or the beating heart (n = 8). In 17 patients with nonischemic mitral valve insufficiency the mitral valve was repaired. Closed-chest cardiopulmonary bypass with cardioplegic arrest (Port-Access technique; Heartport, Inc, Redwood City, Calif) was used for arrested-heart total endoscopic coronary bypass and mitral valve repair. RESULTS: The da Vinci system allows for precise tissue handling and enables the endoscopic performance of cardiac surgical tasks that require a high degree of dexterity (coronary anastomosis, mitral valve repair). No technical mishaps have occurred. The internal thoracic artery was successfully taken down in 79 of 81 patients in the group undergoing minimally invasive coronary bypass and, after a steep learning curve, is currently performed in less than 40 minutes. The postoperative patency rate is 96.3%. Total endoscopic coronary bypass was completed in 22 of 27 cases with 95.4% patency as demonstrated by angiography at 3 months' follow-up. Closed-chest endoscopic beating-heart bypass grafting was successfully performed in 2 out of 8 patients with the use of a new endoscopic stabilizer. In the group having mitral valve repair, primary endoscopic computer-enhanced repair was successfully completed in 14 of 17 patients; three others had to be changed to a standard endoscopic technique, including 1 who required valve replacement. At 3 months' follow-up, 1 additional patient underwent early reoperation for recurrent mitral insufficiency. Overall early and late mortality in this cohort of 148 patients was 2.0% and was not related to the use of the system. CONCLUSION: In conclusion, computer-enhanced endoscopic cardiac surgery can be performed safely in selected patients. Internal thoracic artery takedown is now routinely performed with good results. Total endoscopic coronary bypass is feasible on the arrested heart but does not offer a major benefit over the minimally invasive direct approach because cardiopulmonary bypass is still required. The early clinical experience with closed-chest beating-heart bypass grafting outlines the limitations of this approach despite some procedural success.     

Current status and future directions in computer-enhanced video- and robotic-assisted coronary bypass surgery

Since 1997, both the Cleveland Clinic and London Health Sciences Centre groups have embraced robotic assistance and more recently demonstrated the efficacy of this technology in totally closed-chest, beating heart myocardial revascularization. This endeavor involved an orderly progression and the learning of new surgical skill sets. We review the evolution of robot-enhanced coronary surgery and forecast the future of endoscopic and computer-enhanced, robotic-enabling technology for coronary revascularization. This report describes a computer-assisted totally closed-chest coronary bypass operation, and preliminary results are discussed. The internal thoracic artery (ITA) was harvested through three 5-mm access ports and prepared and controlled endoscopically. A prototype sternal elevator was used to increase intrathoracic working space. A 10-mm endoscopic stabilizer was placed through the second intercostal space, and the left anterior descending coronary artery was controlled with silastic snares. Telerobotic anastomoses were completed end-to-side using custom-made, double-armed 8-0 polytetrafluroethylene sutures. To date, 84 patients have undergone successful myocardial revascularization with robotic assistance with a 0% surgical mortality rate. ITA harvest, anastomotic, and operating times for the entire group have been longer than for conventional surgery at 61.3 +/- 17.9 minutes, 28.5 +/- 28.2 minutes, and 368 +/- 129 minutes, respectively. Bleeding, ventilatory times, arrhythmias, hospital lengths of stay, and return to normal activity have been reduced. Recently, we have developed a new robotic revascularization strategy called Atraumatic Coronary Artery Bypass that is a promising mid-term step on the pathway to totally endoscopic, beating-heart coronary artery bypass. We conclude that computer-enhanced robotic techniques are safe, and further clinical studies are required to define the full potential of this evolving technology.     

Experiences in robotically enhanced IMA-preparation as initial step towards totally endoscopic coronary artery bypass grafting

AIM: To evaluate the feasibility of robotically enhanced preparation of internal mammary arteries (IMA). METHOD: Via three trocars in left thoracic wall the left, right or both IMA were skeletonized under CO(2) insufflation and single lung ventilation using electrocautery. RESULTS: In 12 months, 26 LIMA, five BIMA and one RIMA were dissected. In five patients, the procedure had to be determined (IMA injury (two), respiratory insufficiency (two), and heart penetration (one)). Mean intrathoracic pressure was 9.7+/-1.5 mmHg. Mean time for LIMA and RIMA dissection was 66.7+/-21.1 and 99.2+/-8.7 min, respectively. In 10 patients, pericardium was incised and course of LAD assessed. However, in two patients, this coronary did not correlate with LAD. Time for instrument change depended on type of tool (cautery blade: 24.9+/-13.1 s, clip applier 72.8+/-28.4 s). CONCLUSION: Robotic dissection of IMA is reasonable. However, life-threatening complications can barely be managed due to inadequate tools and excessive time for instrument change. Incorrect determination of coronaries can result in misplaced anastomoses.     

Bilateral internal thoracic artery grafting: midterm results of composite versus in situ crossover graft

BACKGROUND: Two common techniques of bilateral internal thoracic artery grafting are the composite T graft and in situ crossover graft. The superiority of one method over the other has not yet been established. METHODS: From April 1996 to July 1999, bilateral skeletonized internal thoracic arteries were used as T grafts (composite group, n = 649) and in situ grafts (cross group, n = 351) in 1,000 consecutive patients. In the cross group, in situ right internal thoracic artery was routed anterior to the aorta across the midline for grafting to the left anterior descending artery, and the left internal thoracic artery was used for the circumflex branches. RESULTS: The two groups had comparable preoperative risk profiles. Bypass time and aortic cross-clamping time were longer in the composite group (80 +/- 38 and 67 +/- 29 minutes versus 66 +/- 43 and 55 +/- 34 minutes, respectively). Number of anastomoses per patient was similar (3.1 versus 3.2). However, more sequential anastomoses were performed in the composite group (62% versus 53%), and the gastroepiploic artery was used more often in the cross group (30% versus 19%). Thirty-day mortality was 3.9% in the composite and 2.3% in the cross group (not significant). Occurrence of postoperative complications (sternal infection, myocardial infarction, cerebrovascular accident, and bleeding) was similar. Late follow-up (2 to 56 months) showed increased return of angina (6% versus 3.1%; p = 0.046) and decreased 4-year survival (Kaplan-Meier; 86% +/- 2.7% versus 92.4% +/- 1.5%; p = 0.07) in composite patients. CONCLUSIONS: Early results of bilateral internal thoracic artery grafting with composite T graft are comparable with those of in situ grafts. However, increased angina return and decreased midterm survival led us to recommend in situ grafting whenever technically possible.     

Totally endoscopic atrial septal repair in adults with computer-enhanced telemanipulation

OBJECTIVE: Standard surgical closure of an atrial septal defect via sternotomy is a safe and effective procedure with low morbidity and mortality. Considering that young female patients are frequently operated on for atrial septal defects, a minimally invasive procedure avoiding sternotomy is convincingly desirable and led to the approach through a right anterolateral minithoracotomy. The recent clinical introduction of robotically assisted surgery further reduced skin incisions and enabled totally endoscopic procedures through ports. This article reports on a first series of atrial septal defect closures of which the first case was operated on August 24, 1999, in a totally endoscopic closed chest technique using a computer-enhanced telemanipulation system. METHODS: We performed totally endoscopic atrial septal repair using the da Vinci surgical system (Intuitive Surgical, Mountain View, Calif) in 10 consecutive adult patients. Median age was 45.5 +/- 10.0 years, and preoperative New York Heart Association functional class was 1.8 +/- 0.1. Left ventricular ejection fraction was normal in all patients and mean pulmonary artery pressure amounted to 35 +/- 7 mm Hg. Shunt volume ranged from 24% to 70%. All patients displayed a fossa ovalis type of atrial septal defect; 2 of them multiperforated. RESULTS: Neither intraoperative nor postoperative complications occurred. Two patients had to be converted to minithoracotomy due to endoaortic balloon clamp failure. Length of operation was 262 +/- 37 minutes, and cardiopulmonary bypass time was 161 +/- 26 minutes. Intraoperative transesophageal echocardiography certified complete closure of the atrial septal defect in all patients. The totally endoscopic computer-enhanced technique yielded excellent cosmetic results. CONCLUSION: Totally endoscopic atrial septal repair is a feasible and safe procedure with good clinical results and excellent cosmetic outcomes. It may be considered as perfect adjunct to interventional treatment options. Further studies with larger cohorts and randomized trials are necessary to document potential benefits. Evolution in robotic technology and refinement of procedural flow may shorten procedural time and decrease costs.     

Bilateral internal thoracic artery grafting: long-term clinical and angiographic results of in situ versus Y grafts

BACKGROUND: We evaluated whether bilateral internal thoracic arteries provide the same long-term results when used as in situ grafts and as Y grafts.Methods and Results: From October 1991 to February 2000, 1818 patients had bilateral internal thoracic arteries used as in situ (n = 1378, group A) or as Y grafts (n = 440, group B). The number of anastomoses per patient and the number of bilateral internal thoracic artery anastomoses per patient were higher in group B (3.1 +/- 0.9 and 2.7 +/- 0.9) than in group A (2.9 +/- 0.8 and 2.2 +/- 0.6) (both P <.001). The number of right internal thoracic artery anastomoses per patient rose from 1.0 +/- 0. 3 in group A to 1.4 +/- 0.6 in group B (P <.001), and the number of sequential anastomoses per right internal thoracic artery graft rose from 4.1% to 34.3% (P <.001). Thirty-day mortality was 2.0% in group A versus 2.5% in group B (P = not significant). No difference in postoperative course was detected. Eight-year survivals were 95.8% +/- 2.7% in group A versus 94.8% +/- 4.0% in group B (P = not significant), and event-free survivals were 95.2% +/- 2.9% in group A versus 93.6% +/- 4.4% in group B (P = not significant). Early angiograms were obtained in 295 patients (945 anastomoses, 863 distal and 82 proximal Y grafts), 213 patients (611) in group A and 82 patients (334) in group B. Patency rate was 98.8% in group A and 96.0% in group B (P = not significant), whereas grade A patency rate was 97.2% in group A and 96.4% in group B (P = not significant). Late angiograms were obtained in 88 patients (25 in group A and 63 in group B) at a mean of 17.5 +/- 18.4 months: patency rate was 100% in group A and 99.2 in group B (P = not significant), and grade A patency rate was 98.6% in group A and 98.8% in group B (P = not significant). No Y anastomosis was occluded or stenosed. COMMENT: Survival, incidence of cardiac events, and angiographic patency in the early and late phases are similar for bilateral internal thoracic arteries used either in situ or as Y grafts. However, Y grafting with bilateral internal thoracic arteries increases the number of anastomoses per bilateral thoracic artery, as well as the flexibility of the right internal thoracic artery.     

Early experience with robotically assisted internal thoracic artery harvest

We sought to determine the efficacy of using robotic assistance to facilitate endoscopic harvesting of internal thoracic arteries (ITAs). A total of 104 patients had ITAs harvested endoscopically with use of both the AESOP 3000 system (Computer Motion, Goleta, CA, U.S.A.) and Zeus robotic telesurgical system (Computer Motion). All ITAs were harvested with a harmonic scalpel (Ethicon Endosurgery, Cincinnati, OH, U.S.A.). With the left lung collapsed, ITAs were harvested with CO2 insufflation through three 5-mm ports in the left chest. All patients tolerated insufflation without hemodynamic compromise. Average ITA harvest time was 61.3 +/- 20.9 minutes. Intraoperative graft flows averaged 36.3 +/- 22.4 mL/min. There were three distal ITA injuries; all other vessels were patent after harvesting and demonstrated no angiographic evidence of injury. This article demonstrates a technique by which ITA can be safely harvested totally endoscopically with use of computer-enhanced robotic systems and a harmonic scalpel, allowing complete pedicle dissection through 5-mm ports with minimal ITA manipulation.     

Endoscopic computer-enhanced beating heart coronary artery bypass grafting

Background. Telemanipulation systems have enabled coronary revascularization on the arrested heart. The purpose of this study was to develop a technique for computer-enhanced endoscopic coronary artery bypass grafting on the beating heart.

Methods. The operation was performed using the daVinci telemanipulation system. Through three ports, the left internal thoracic artery was harvested in 10 mongrel dogs (30 to 35 kg) using single right-lung ventilation and CO₂ insufflation. Through a fourth port an articulating stabilizer, manipulated from a second surgical console, was inserted to stabilize the heart. The left anterior descending artery was snared using silicone elastomer slings anchored in the stabilizer cleats and the graft to coronary artery anastomosis was performed.

Results. In 7of 10 dogs, total endoscopic beating heart bypass grafting, cardiac stabilization, arteriotomy, and arterial anastomosis were performed using computer-enhanced technology. Endoscopic stabilization and temporary left anterior descending artery occlusion were well tolerated. All grafts were patent although minor strictures were found in 2. In 3 dogs, the procedure could not be completed (1 ventricular arrhythmia, 1 left atrial laceration, and 1 right ventricular outflow tract compression).

Conclusions. Endoscopic beating heart coronary artery bypass grafting is possible in a canine model using a computer-enhanced instrumentation system and articulating stabilization.     

Totally endoscopic coronary artery bypass grafting on cardiopulmonary bypass with robotically enhanced telemanipulation: report of forty-five cases

BACKGROUND: Robotically enhanced telemanipulation is a new powerful tool for minimally invasive procedures that allows totally endoscopic cardiac surgery. Between June 1999 and February 2001, 45 robotically enhanced totally endoscopic coronary artery bypass grafting procedures on the arrested heart were performed at our institution with the use of the da Vinci telemanipulation system (Intuitive Surgical, Inc, Mountain View, Calif). METHODS: In 37 patients a single-vessel totally endoscopic coronary bypass operation was performed. Eight patients had different types of multivessel revascularization with both internal thoracic arteries. The initial conversion rate was 22% and dropped to 5% in the last 20 patients. Two patients required reexploration via median sternotomy. The first 22 patients had excellent graft patency on discharge. The procedural time for single-vessel totally endoscopic bypass was 4.2 +/- 0.4 hours, bypass time was 136 +/- 11 minutes, and aortic crossclamp time amounted to 61 +/- 5 minutes. CONCLUSION: The present data show the feasibility of closed chest single- and double-vessel revascularization, with good clinical results. However, procedural time is prolonged and the complex endoscopic and endoaortic occlusion techniques, as well as the extensive anesthesiologic monitoring, are demanding. The need for conversion to an open procedure diminished after a relatively short learning curve. All postulated benefits of totally endoscopic surgery other than excellent cosmesis must be evaluated in larger cohorts.     

Coronary artery bypass grafting in the conscious patient without endotracheal general anesthesia

BACKGROUND: Over the past several years, considerable experience has accumulated in performing coronary anastomoses on the beating heart, and various aspects of minimally invasive approaches have been simplified. In an attempt to further simplify and decrease the "invasiveness" of this procedure, performing this operation without endotracheal general anesthesia was deemed feasible in certain subsets of patients. METHODS: Between October 1998 and June 1999, 5 patients underwent coronary artery bypass grafting without endotracheal general anesthesia, using high thoracic epidural block to construct extension grafts with a short segment of radial artery, between the in situ left or right internal thoracic arteries and the left anterior descending (n = 4) or right coronary arteries (n = 1). There were 2 female and 3 male patients, with a mean age of 67.4 +/- 8.3 years. RESULTS: The perioperative course of the patients was uneventful. There was no perioperative morbidity or mortality. No patient was converted to general anesthesia or to conventional operation. Control angiograms revealed patent anastomoses in all patients. In 1 patient, spasm of the radial artery graft was observed that was relieved 3 weeks later spontaneously. Mean length of hospital stay was 2.2 +/- 0.4 days. All patients were symptom free and returned to normal daily life at the first postoperative month. CONCLUSIONS: Our initial experience confirms the feasibility of performing coronary bypass grafting in the conscious patient without endotracheal general anesthesia.     

A comparison of robot-assisted versus manually constructed endoscopic coronary anastomosis

BACKGROUND: New technology has enabled surgeons to attempt totally endoscopic coronary artery bypass grafting. Our purpose was to compare three different techniques of totally endoscopic anastomosis using a porcine animal model. METHODS: Porcine hearts were excised and the right coronary artery was dissected free for use as an arterial graft. The hearts were placed in a human thoracic model and an endoscopic arterial anastomosis between the free right coronary artery and the left anterior descending coronary artery was performed using one of the following: (1) two-dimensional visualization with straight endoscopic instruments (n = 8); (2) three-dimensional head-mounted visualization with curved endoscopic instruments (n = 7); or (3) three-dimensional visualization with robotic telemanipulation (n = 8). Pathologic analysis of suture placement, vessel trauma, and patency was performed. Anastomoses were graded according to quality, ease, and patency using a seven-point Likert scale (1 = excellent, 7 = very poor). RESULTS: Endoscopic anastomotic ease and quality were significantly improved when three-dimensional visualization and curved endoscopic instruments were employed. Telemanipulation enhanced the process and provided the best operative results with regard to time required to construct the anastomosis, as well as ease and quality. CONCLUSIONS: Totally endoscopic anastomosis is feasible using currently available technology. Three-dimensional visualization and robotic telemanipulation significantly facilitate anastomosis construction and will likely benefit clinical operative outcome.     

Revascularization of the lateral wall: long-term angiographic and clinical results of radial artery versus right internal thoracic artery grafting

OBJECTIVE: We sought to evaluate whether the radial artery provides the same results as the right internal thoracic artery in lateral wall revascularization in the long term. METHODS: From January 1992 to September 1996, 288 patients had myocardial revascularization with the left internal thoracic artery anastomosed to the left anterior descending coronary artery. The lateral wall was grafted with the radial artery in 139 patients (group A) and with the right internal thoracic artery in 149 patients (group B). Groups were different only because of older age and a higher incidence of patients requiring urgent treatment in group A. Y grafting was used in 86.4% of patients in group A and in 34.8% of patients in group B (P < .001). Anastomoses per patient were similar in both groups (3.2 +/- 0.8 vs 3.2 +/- 0.9, P = 1.000). RESULTS: Thirty-day mortality was similar (2.1% vs 2.0%, P = .722). There were 15 late deaths in group A versus 11 in group B (P = .418). Cause of death was cardiac related in 6 patients in group A versus 7 in group B. Late redo or percutaneous transluminal coronary angioplasty was performed in 3 patients in group A and in 1 patient in group B (P = 0.538). Eight-year survival was 86.7% +/- 2.9% in group A versus 89.6% +/- 2.8% in group B (P = .477); event-free survival was 84.2% +/- 3.2% versus 88.9% +/- 2.9%, respectively (P = .430). The patency rate within 30 days was 99.1% in group A (105/106 left internal thoracic artery plus radial artery anastomoses) versus 100% in group B (52/52 bilateral internal thoracic artery anastomoses; P = .715). After a mean of 35 +/- 28 months, the patency rate was 99.0% in group A (100/101 left internal thoracic artery plus radial artery anastomoses) and 100% in group B (33/33 bilateral internal thoracic artery anastomoses, P = .560). CONCLUSION: In the long-term, lateral wall grafting with the radial artery provides the same clinical and angiographic results as right internal thoracic artery grafting.     

Photodynamic therapy reduces intimal hyperplasia in prosthetic vascular bypass grafts in a pig model.

BACKGROUND: Bypass surgery has a failing frequency of 30% during the first year, mainly due to intimal hyperplasia (IH). This negative effect is most pronounced in artificial grafts. Photodynamic therapy (PDT) is a technique in which light activates photosensitizer dyes to produce free-radicals resulting in an eradication of cells in the vascular wall. The aim of this study was to determine the effectiveness of PDT to reduce IH in a preclinical porcine PTFE bypass model. MATERIAL AND METHODS: Ten pigs were used. After a pilot PDT dosimetry study (n=3) PTFE grafts were bilaterally placed into the circulation as bypasses from the common to the external iliac arteries (n=7). The right sides served as controls (C). Before implantation of the left grafts, the arterial connecting sites of the left distal anastomoses were PDT-treated. The arteries were pressurized at 180 mmHg for 5 minutes with the photosensitizer Methylene Blue (330 microg/ml), and thereafter endoluminally irradiated with laser light (lambda = 660 nm, 100 mW/cm(2), 150 J/cm(2)). After 4 weeks the specimens were retrieved and formalin fixed. Cross sections through the midportions of the distal anastomoses and the grafts were used for histology, immunohistochemistry to identify inflammatory cells and morphometric evaluation (n=7). RESULTS: No systemic side effects and no graft occlusions were noted. PDT-treated anastomoses showed reduced IH in the mid-portions of the anastomoses (Area of IH: microm(2)/microm graft: C: 6970+/-1536, PDT: 2734+/-2560; P<0.005) as well as in the grafts (C: 5391+/-4031, PDT: 777+/-1331; P<0.02). The number of inflammatory cells per microscopic field was increased after PDT (C: 24+/-16, PDT: 37+/-15; P<0.009). CONCLUSIONS: Adjuvant PDT, performed in an endovascular fashion, was a safe method to reduce prosthetic graftstenosis in a preclinical setting. This study underscores the clinical potential of PDT to inhibit the development of clinical bypass graftstenosis.     

Stapled coronary anastomosis with minimal intraluminal artifact: The S2 Anastomotic System in the off-pump porcine model

OBJECTIVE: A reliable, easy-to-use, 1-shot anastomotic device will significantly push the barrier for less invasive coronary bypass surgery. The current study was designed to test the safety, efficacy, and early patency of a novel distal anastomotic device. METHODS: The S2 Anastomotic System (iiTech BV, Amsterdam, The Netherlands) was used in 10 consecutive pigs (73 kg) on a mild antiplatelet regimen. In each animal, the device was used to create an internal thoracic artery to left anterior descending bypass on the beating heart. The anastomoses were evaluated intraoperatively (n = 10), at 2 days (n = 2), and at 5 weeks (n = 8) by functional flow measurements, postmortem angiography, and histomorphologic examination. RESULTS: In all pigs, the S2 Anastomotic System rapidly created successful anastomoses at the first attempt (graft loading and coronary ischemia time: 1.2 +/- 0.3 minutes and 3.0 +/- 0.6 minutes) on target vessels of 1.6 to 2 mm inner diameter. There were no technical failures or anastomotic leaks requiring additional sutures. Both intraoperatively and at the time of death, ischemically induced peak hyperemic flow responses demonstrated widely patent bypasses, which were confirmed by postmortem angiography (FitzGibbon grade A, n = 10) and macroscopic evaluation (anastomotic orifice: 2 mm). Histomorphologic evaluation showed a normal healing response with negligible neointima covering the connector and limited streamlining repair tissue formation between the staple-like elements of the connector. CONCLUSIONS: The S2 Anastomotic System consistently created automated, fast, and reliable internal thoracic to coronary artery anastomoses on the porcine beating heart with excellent graft patency and healing characteristics at the 5-week follow-up.     

Evaluation of an internal thoracic artery as a coronary artery bypass graft by intercostal duplex scanning ultrasonography

OBJECTIVES: Although angiography is often used to determine whether the internal thoracic artery is appropriate as a coronary bypass graft, but use of duplex scanning ultrasonography for this purpose is not yet widespread. METHODS: The internal diameter and flow of the internal thoracic artery were measured using intercostal duplex scanning in 100 patients during April 1995. The ultrasonographic device (sonos 2000, Hewlett Packard) used had a linear probe delivering a frequency of 7.5 MHz. Bilateral internal thoracic arteries and their blood flow were imaged clearly in all subjects. Diameter was compared by angiography and duplex scanning ultrasonography in 20 patients. RESULTS: The average internal diameter of internal thoracic artery was 2.19 +/- 0.46 mm (right) or 2.13 +/- 0.32 mm (left) in men and 2.05 +/- 0.44 mm (right) or 2.09 +/- 0.42 mm (left) in women. The gender difference was statistically significant (p = 0.05). The maximum systolic blood flow velocity through the internal thoracic artery was 0.85 +/- 0.34 m/s (right) or 0.84 +/- 0.36 m/s (left) in men and 0.87 +/- 0.28 m/s (right) or 0.82 +/- 0.28 m/s (left) in women. The average internal thoracic arterial blood flow (F) was 54.6 +/- 29.0 ml/min (right) or 50.9 +/- 28.8 ml/min (left) in men and 56.8 +/- 38.2 ml/min (right) or 58.2 +/- 33.4 ml/min (left) in women. Duplex scanning ultrasonography using an intercostal approach enables easy imaging of bilateral internal thoracic arteries and visualizes entire internal thoracic artery structure by simply changing the probe position. CONCLUSION: Intercostal duplex scanning ultrasonography is thus recommended for reliable evaluation of the internal diameter and blood flow of the internal thoracic artery.     

Fractional flow reserve of pedicled internal thoracic artery and saphenous vein grafts 6 months after bypass surgery.

BACKGROUND: Although the internal thoracic artery was proven superior to saphenous vein graft in long-term patency, it is thought to be a more resistive conduit than the vein graft. Moreover, patency studies comparing both left and right internal thoracic arteries have provided results favoring the former. Fractional flow reserve is an established functional index of coronary blood flow. METHODS: To compare the fractional flow reserve between both internal thoracic arteries and saphenous vein grafts, 43 bypass grafts were studied 6 months after revascularization. Intra-graft pressures were measured during cardiac catheterization using a pressure-wire advanced to the first distal anastomosis of 12 left internal thoracic arteries (ITAs), 10 right ITAs and of 21 vein grafts. Pressure gradients between the aorta and the graft were measured at baseline and during a maximal hyperemia. RESULTS: At baseline, pressure gradient was recorded in the left ITA (2.9+/-2.2 mmHg), in the right ITA (1.2+/-1.2 mmHg) and in the vein graft (0.4+/-0.7 mmHg). During maximal hyperemia, pressure gradient increased to 9.6+/-3.2 mmHg in left ITA, to 4.5+/-2.0 mmHg in the right ITA (p<0.001 vs left ITA) and to 3.3+/-2.7 mmHg in vein (p<0.001 vs left ITA; NS vs right ITA). Fractional flow reserve was 0.90+/-0.04 in left ITA, 0.95+/-0.03 in right ITA (p<0.01 vs left ITA) and 0.96+/-0.03 in vein (p<0.001 vs left ITA). CONCLUSION: Internal thoracic arteries and saphenous vein grafts allow myocardial revascularization with minimal resistance to maximal blood flow. The resistance appears significantly higher in left ITA compared to both the right ITA and venous grafts.     

Robotic skeletonizing of the internal thoracic artery: is it safe?

BACKGROUND: The advantages of internal thoracic artery skeletonization include early high blood flow, a longer conduit, and less bleeding than pedicle internal thoracic artery grafts. Longer conduits are needed for complete endoscopic arterial revascularization. Therefore this study was designed to determine the feasibility and safety of internal thoracic artery skeletonization using the da Vinci robotic system (Intuitive Surgical, Sunnyvale, CA). METHODS: Nine dogs underwent bilateral robotic internal thoracic artery harvesting through three ports placed in the left chest. One internal thoracic artery was harvested as a pedicle in each dog, and the other was skeletonized. Internal thoracic artery blood flow was measured in each graft, and comparative endothelial histologic studies were performed. Data are mean +/- the standard error of the mean. RESULTS: All 18 internal thoracic arteries were harvested successfully. Skeletonized internal thoracic artery harvests required more time (48.0 minutes +/- 1.8) than pedicle internal thoracic artery harvests (39.0 minutes +/- 1.4; p < 0.05). Internal thoracic artery flows during the final intervals were similar (skeletonized = 30.0 mL/min +/- 2.4 vs pedicle = 31.5 mL/min +/- 1.8; p = 0.9). Free internal thoracic artery bleeding flow was similar in both groups (skeletonized = 162.0 mL/min +/- 3.0 vs pedicle = 189.0 mL/min +/- 2.4; p = 0.4). Histologically, both groups were similar with minimal endothelial damage. CONCLUSIONS: Robotically skeletonized harvesting is safe, but it requires more time (48.0 minutes +/- 1.8) than pedicle internal thoracic artery harvesting. Despite muted tactile feedback with robotics, neither technique was associated with histologic or functional damage. These encouraging results may represent an advantage for complete arterial revascularization in robotic coronary bypass patients.     

A xiphoid approach for minimally invasive coronary artery bypass surgery.

BACKGROUND: The premise for adopting minimally invasive cardiac surgery techniques for myocardial revascularization is to reduce the patient's morbidity without compromising the efficacy of conventional coronary artery bypass. However, opening the pleura has been a limitation of using these approaches. Aim: We used the xiphoid approach as an alternative to opening the pleura and to minimize pain after minimally invasive coronary artery bypass surgery. METHODS: We review our surgical experience in 55 patients who underwent minimally invasive direct coronary artery bypass (MIDCAB) surgery through a xiphoid approach between October 1997 and August 1999. Thoracoscopy (n = 31) or direct vision (n = 24) were used for internal mammary artery (IMA) harvesting. Mean patient age was 67 +/- 10 years and 65% were men. The mean Parsonnet score was 23 +/- 10. Performed anastomoses included left IMA (LIMA) to the left anterior descending (LAD) artery (n = 53), LIMA-to-LAD and saphenous vein graft from the LIMA to the right coronary artery (n = 1), and LIMA-to-LAD and right IMA (RIMA) to right coronary artery (n = 1). RESULTS: Postoperative complications included atrial fibrillation (12%), acute noninfectious pericarditis (12%), and acute renal failure (5%). Mean postoperative length of stay was 4 +/- 2 days. Angiography was performed in 16 patients and demonstrated excellent patency of the anastomoses. There was no operative mortality. Actuarial survival was 98% in a mean follow-up period of 11 +/- 5 months. CONCLUSIONS: Minimally invasive coronary artery bypass can be performed safely through a xiphoid approach with low morbidity, mortality, and a relatively short hospital stay.