[The ECG-gated 4-row multidetector CT of the heart in preoperative imaging minimal invasive coronary artery bypass grafting]. / Die EKG-getriggerte 4-Zeilen-Spiral-CT des Herzens in der präoperativen Bildgebung vor minimalinvasiver koronarer Bypass-Operation.

PURPOSE: Minimal invasive direct coronary artery bypass grafting (MIDCAB) or off-pump coronary artery bypass grafting (OPCAB) on the beating heart with full or mini-sternotomy are becoming more common in coronary bypass surgery of the left anterior descending (LAD). In the decision, which surgical approach (MIDCAB, OPCAB or conventional surgery with cardiopulmonary bypass) will be best used, knowledge of the anatomical field is of major importance. The aim of the study was to evaluate retrospective ECG-gated 4-row multidetector CT (MDCT) in patients planned for MIDCAB as additional imaging to coronary angiography. MATERIAL AND METHODS: The study included 25 consecutive patients. MSCT was performed as unenhanced (collimation 4 x 2.5 mm) and contrast-enhanced examination (140-170 ml, 300 mg Iodine/ml, collimation 4 x 1 mm). The evaluation included presence of LAD calcifications, distance of LAD and left internal mammarian artery (LIMA), course of LAD and LIMA, the presence or absence of bridging through myocardium or epicardial fat and the presence of pleural fibrosis. The MDCT results were correlated with intra-operative findings. RESULTS: All MDCTs could be assessed with reference to the demands. In 20/25 operations, MDCT had direct influence as to the selection of the surgical approach (11 MIDCAB, 7 OPCAB with mini-sternotomy and 5 with full sternotomy, 2 conventional surgeries). The distance of LAD and LIMA varied from 0.9 to 4.5 cm in MDCT. As to calcifications, 3/25 correlated patients had calcifications and 10 patients had no calcifications in the middle LAD. Seven patients had intraoperative fibrosis of the vessel wall without calcification of the middle LAD, which could not be detected with MDCT. Another 5 patients had single calcified plaques in the middle LAD, 4 of these had a fibrosis of the vessel and 1 had a normal vessel at surgery. In these cases, the anastomosis was done between the calcified plaques. No myocardial bridging was detected by MDCT and at surgery. Bridging of epicardial fat was shown by MDCT and at surgery in 9/25 patients and was excluded in 15 patients. In 1 patient, the LAD seemed to run superficially in MDCT, but was covered with fat as seen during surgery. The course of the LIMA was inconspicuous in all cases, no pleural fibrosis was found. CONCLUSIONS: The 4-row MDCT has proven to be adequate in addition to coronary angiography for preoperative evaluation in patients scheduled for MIDCAB and provides the surgeon with relevant information for the selection of the operative approach.

15-Deoxyspergualin for induction of graft nonreactivity after cardiac and renal allotransplantation in primates.

In order to assess the immunosuppressive potentials of 15-deoxyspergualin (15-DS) in a preclinical experiment, heterotopic cardiac (n = 27, group I) and classic renal (n = 25, group II) allotransplantations were performed in Chacma baboons. The following immunosuppressive regimens were applied: Groups IB and IIB were treated with 15-DS alone (4 mg/kg/day) for p.o. days 0-9. Groups IC and IIC were treated with cyclosporine A (10-40 mg/kg/day) for p.o. days 0-30. Groups ID and IID received a combination of 15-DS (for p.o. days 0-9) and CsA (for p.o. days 0-30). Groups IA and IIA served as control and received no medication. The mean graft survival was 11.0 days for group IA, 28.2 days for group IB (P less than 0.05; IB vs. IA), 32.4 days for group IC, and 43.1 days for group ID (P less than 0.025; ID vs. IA). After renal transplantation, the corresponding figures were 12.3 days for group IIA, 8.5 days for group IIB, 30.4 days for group IIC and 148.9 days for group IID (P less than 0.025; IID vs. IIA). After cardiac and renal transplantation, acute rejection was the main cause of graft failure. Treatment-related side effects, mainly gastrointestinal complications, were observed only in primates, who were treated with 15-DS alone. After cardiac transplantation, permanent graft non-reactivity was not achieved, but a delayed rejection occurred within a mean of 21.8 days after immunosuppression had been stopped. Following renal transplantation, graft nonreactivity was also not achieved in groups IIB and IIC. In group IID, however, 4 of 8 animals (50%) were graft-tolerant 340, 256, 244, and 164 days after treatment discontinuation. Thus, the combination of 15-DS and CsA led to a significant prolongation of graft survival in both groups. Long-term nonreactivity was achieved only after renal transplantation, when initially treated with 15-DS and CsA.

Use of the voice-controlled and computer-assisted surgical system ZEUS for endoscopic coronary artery bypass grafting.

OBJECTIVE: With the aim of performing a completely endoscopic coronary bypass anastomosis, we have undertaken an experimental and clinical study using robotic instrumentation and voice-controlled camera guidance. METHODS: The ZEUS Robotic Surgical System (Computer Motion Inc, Goleta, Calif) consists of three interactive robotic arms and a control unit, allowing the surgeon to move the instrument arms in a scaled down mode. The third arm (AESOP, Computer Motion) positions the endoscope via voice control. PHASE I: In a phantom model, vascular grafts were anastomosed to the left anterior descending coronary artery (LAD) of 50 pig hearts with either 2- or 3-dimensional visualization. PHASE II: In 6 dogs (FBI 20-25 kg) the left internal thoracic artery (LITA) was harvested endoscopically. Then the animals were placed on an endovascular cardiopulmonary bypass system (Port-Access, Heartport, Inc, Redwood City, Calif). Anastomosis of the LITA to the LAD was performed endoscopically with the telemetric ZEUS instruments. Flow rates through the LITA were measured by Doppler analysis. PHASE III: Two patients were operated on with the ZEUS system. After endoscopic harvesting of the LITA and cardiopulmonary bypass with the Port-Access system, the bypass graft (LITA-LAD) was anastomosed endoscopically with the ZEUS system through three thoracic ports. RESULTS: In the dry laboratory, the time range required for the robotically assisted coronary anastomosis was 35 to 60 minutes with 2-dimensional visualization and 16 to 32 minutes with 3-dimensional visualization. In the animal experiments, the median time for endoscopic harvesting of the LITA was 86 minutes (range 56-120 minutes) and for the anastomosis, 42 minutes (range 35-105 minutes); flow rates through the LITA ranged between 22 and 45 mL/min. In the clinical cases, preparation times for the LITA were 83 and 110 minutes, respectively, and anastomosis times, 42 and 40 minutes, respectively. Doppler flow rates measured 125 and 85 mL/min, respectively. Both patients had an uneventful follow-up angiogram and postoperative course. CONCLUSIONS: With sophisticated robotic technology, a completely endoscopic anastomosis of the LITA to the LAD is possible, allowing technically precise operations within acceptable time limits.

Three-dimensional video and robot-assisted port-access mitral valve operation.

BACKGROUND: In order to minimize surgical trauma, video-assisted mitral valve operation has been started using the Port-Access technique with the addition of a three-dimensional visualization system (Vista Cardiothoracic Systems Inc, Westborough, MA) and a voice-controlled camera-holding robotic arm (Aesop; Computer Motion Inc, Goleta, CA). METHODS: Port-Access mitral valve replacement or repair (PAMVR) was undertaken using an endovascular cardiopulmonary bypass (CPB) system. Fifty patients underwent Port-Access mitral valve replacement or repair. A three-dimensional thoracoscope was inserted allowing complete three-dimensional projection of the mitral valve (Vista). In the last 20 patients, the camera was attached to a robotic arm (Aesop), which allowed stabilization and voice-activated movement of the camera. Mitral valve repair was performed in 26 patients, and the valve was replaced in 24 patients with a mechanical valve prosthesis. RESULTS: Median time of operation was 4.2 hours, aortic cross-clamp time 83 minutes, CPB time 125 minutes, intensive care unit stay 1.5 days and hospitalization 9.0 days. Three months follow-up was complete in 40 patients, with 34 patients (85%) in New York Heart Association class I and 6 patients in class II. Mortality was 0% and rate of reoperation was 2%, with a follow-up time up to 1.5 years postoperatively. CONCLUSIONS: Using three-dimensional video and robotic assistance, it was possible to minimize the length of skin incision, but at the same time to optimally visualize the whole mitral valve apparatus in order to perform true Port-Access mitral valve operation, including various repair techniques.

Minimally invasive coronary artery bypass grafting: port-access approach versus off-pump techniques.

BACKGROUND: Within the past 5 years several surgical techniques have been developed for less invasive surgical treatment of coronary artery disease. The aim of this study was to define specific indications for the various minimally invasive coronary artery surgical procedures. METHODS: Minimally invasive direct coronary artery bypass grafting through a minithoracotomy was performed in 67 patients. The left internal mammary artery was anastomosed on the beating heart with the use of a pressure or suction stabilizer without the use of extracorporeal circulation. In 58 other patients with multivessel disease, the off-pump coronary artery bypass grafting technique through a sternotomy was applied with a left internal mammary artery to left anterior descending artery and additional vein grafts without extracorporeal circulation. In a third group, Port-Access (Heartport Inc, Redwood City, CA) coronary artery bypass grafting was performed through a left minithoracotomy with the use of an endovascular extracorporeal circulation system and cardioplegic arrest. Angiographic follow-up was complete in 64% of the patients. RESULTS: There was minimal perioperative or postoperative mortality (0.5%). The medium surgical procedure time for all minimally invasive and off-pump procedures was 2.5 hours; it was 4.5 hours for Port-Access procedures. The median postoperative intensive care unit stay was 1.0 days, and the median hospitalization was 5.0 days. Overall graft patency was 97.3%; in 8 patients (4.1%) a stenosis either at or distal to the graft anastomosis was dilated with coronary angioplasty. CONCLUSIONS: For single-vessel disease of the left anterior descending artery, the minimally invasive coronary artery bypass grafting procedure can be performed safely without the use of extracorporeal circulation. In case of hemodynamic instability or anatomic variation, the Port-Access procedure can be applied without additional necessity for sternotomy. For multivessel disease, the off-pump bypass grafting procedure with sternotomy can be recommended depending on the coronary arteries involved. In case of necessary grafts to the lateral marginal or circumflex branches, Port-Access grafting can be recommended and may play an important role in the future for the development of fully endoscopic robot-assisted coronary artery bypass grafting.

Early experience with robotic technology for coronary artery surgery.

BACKGROUND: To achieve an endoscopic coronary bypass anastomoses we performed a study with endoscopic robotic instrumentation and camera guidance using three-dimensional (3-D) visualization. METHODS: The surgical robotic system ZEUS (Computer Motion Inc, Goleta, CA) consists of three interactive robotic arms and a control unit allowing the surgeon to move the instrument arms in a scaled down mode. The third arm (AESOP, Computer Motion Inc, Goleta, CA) positions the endoscope via voice control. The study had three phases. Phase I: In a phantom model, end-to-side anastomoses between vein grafts and the left anterior descending coronary artery (LAD) of 109 pig hearts were performed. Phase II: In 6 dogs (FBI, 20-25 kg) the left internal mammary artery (LIMA) was harvested endoscopically. During Port-Access (Heartport Inc, Redwood City, CA) cardiopulmonary bypass (CPB), LIMA and LAD were then anastomosed endoscopically with the help of telemetric ZEUS instruments (Computer Motion Inc). Phase III: A total of seven patients were operated on with help of the ZEUS system (Computer Motion Inc). After endoscopic LIMA harvesting and CPB using the Port-Access (Heartport Inc) system, the bypass graft (LIMA to LAD) was anastomosed endoscopically through three thoracic ports in 2 patients. Another 3 patients were operated on off-pump with regional stabilization and 2 patients with sternotomy and routine CPB. RESULTS: The practice with the phantom model and the subsequent animal experiments allowed the surgeons to gain sufficient experience for the clinical setting. In the clinical cases, times for anastomoses ranged from 20 to 42 minutes. Median internal mammary artery flow rate was 74 mL per minute (range 36-110 mL per minute). One patient in the off-pump group was converted to CPB and routine anastomosis. All patients had an uneventful angiographic control and postoperative course. CONCLUSIONS: Using telemetic technology, a completely endoscopic anastomosis of LIMA to LAD is possible on the arrested heart, as well as on the beating heart.

Single vessel revascularization with beating heart techniques -- minithoracotomy or sternotomy?

OBJECTIVE: The purpose of the study was to evaluate the best surgical approach in off-pump single vessel revascularization of the left anterior descending coronary artery (LAD). METHODS: In 256 patients a single left internal mammary artery (LIMA) to LAD bypass was performed with beating heart techniques through a left anterior minithoracotomy (minimally invasive direct coronary artery bypass (MIDCAB), n=129) or a full sternotomy (off-pump coronary artery bypass (OPCAB), n=127). RESULTS: In the OPCAB group, significantly more severe comorbidities (P=0.001) and redo-operations were noted (P<0.001). Conversion to sternotomy or CPB was necessary in five MIDCAB patients and one OPCAB patient. No cerebrovascular accident was seen in both groups. There was no hospital death in MIDCAB- and two deaths in OPCAB procedures (P=ns). There was a significant reduction in time of surgery (P=0.028) and coronary occlusion (P=0.009) in the OPCAB group. No differences in postoperative ventilation time, ICU stay and length of hospital stay were recorded between groups. Wound infections occurred in six MIDCAB patients (4.7%) and one OPCAB patient (0.8%). Early postoperative reoperation due to graft failure was necessary in three patients after MIDCAB and two patients after OPCAB (P=ns). Confirmed by angiography, the early graft patency rate was 96 and 98%, respectively (P=ns). CONCLUSIONS: Both beating heart techniques showed good results with low hospital mortality, low early complications and comparable angiographic results. Nevertheless, MIDCAB is a challenging technique as demonstrated by the longer times of surgery and coronary occlusion with a tendency towards a higher risk of conversion and wound infection. Thus, this technique should only be performed in selected patients with favourable coronary anatomy. Through a sternotomy approach, single vessel revascularization can be performed safely off-pump even in high-risk patients.

Adenosine cardioplegia: reducing reperfusion injury of the ischaemic myocardium?

Hyperkalaemia-induced hypopolarization of the sarcolemnal membrane during standard crystalloid cardioplegic arrest potentiates calcium influx during reperfusion and is associated with depletion of high-energy phosphate reserves. Adenosine has been shown to induce fast cardiac arrest whilst preserving membrane hyperpolarization in an isolated rat heart model. In this study we compared the efficacy of adenosine, both as an arresting agent and as an ultrastructural, haemodynamic and high-energy phosphate preserving agent, in an in situ global ischemia model in the baboon with St. Thomas' Hospital solution No. 2 (ST2; n = 8) and with Krebs-Henseleit buffer (KHB; n = 7). The addition of 10 mM adenosine to the non-cardioplegic KHB (ADO; n = 8) improved haemodynamic recovery significantly in terms of cardiac index (91.6% +/- 7.2 vs 59.9% +/- 9.9) and stroke volume index (101.6% +/- 8.9 vs 55.6 +/- 10.0) and was not statistically distinguishable from the ST2 with regard to cardiac index (91.6% +/- 7.2 vs 94.8% +/- 5.8), stroke volume index (101.6% +/- 8.9 vs 114.0% +/- 8.3) or left ventricular dP/dt (73.1% +/- 9.9 vs 87.0% +/- 12.4). Adenosine triphosphate was best preserved with ADO (103.5% +/- 21.1 vs 67.9% +/- 9.3 and 48.5% +/- 8.7) although this was not statistically significant. This suggests therefore that the mechanism of cardioprotection by adenosine occurs by means other than its role as high-energy phosphate precursor.

[Minimally invasive heart surgery--a fad or a clinically recognized therapy method?]. / Minimal-invasive Herzchirurgie--eine Modeerscheinung oder ein klinisch anerkanntes Therapieverfahren?

Within the last 5 years new less invasive surgical techniques have been developed in the field of cardiac surgery. This new field named "minimally invasive cardiac surgery" can be subdivided into techniques which do not require cardiopulmonary bypass and are used mainly for coronary artery surgery (called minimally invasive direct coronary artery surgery, MIDCAB technique). This MIDCAB procedure can be done through a small left anterior thoracotomy or a sternotomy. In addition there are other methods which allow the performance of complex cardiac surgery through small accesses in combination with the use of an endovascular CPB system and internal aortic clamping to achieve cardioplegic arrest (so-called Port-Access method). Also for valvular surgery, new surgical techniques were developed allowing access to mitral and aortic valves through limited incisions. In addition, new less invasive techniques were developed for congenital heart surgery. This article will describe the various surgical techniques and define the indications for minimally invasive cardiac surgery.

Midterm results and quality of life after minimally invasive vs. conventional aortic valve replacement.

BACKGROUND: This study compares early and mid-term results as well as the quality of life (QOL) between the minimally invasive and conventional aortic valve replacement (AVR). METHODS: Between 7/97 and 4/01, 70 patients (mean age 64.3 +/- 1.3 years) underwent minimally invasive AVR (group M) through an L-shaped ministernotomy. The results were compared to those of 70 conventional AVR (group C) patients during the same period. Patients were equally matched according to age, sex, ejection fraction, valvular lesion, and valve prosthesis. In groups M and C, follow-up was 98.5 % and 95.4 % complete and averaged 34.0 +/- 10.3 and 33.1 +/- 12.9 months, respectively. RESULTS: There were no hospital deaths in group M but two deaths in group C (p = n. s.). Conversion to full sternotomy was necessary in two group M patients. Cross-clamping time (71 +/- 15 min vs. 58 +/- 18 min), cardiopulmonary bypass time (105 +/- 22 min vs. 84 +/- 24 min), and time of surgery (228 +/- 45 min vs. 184 +/- 48 min) were significantly longer in group M. No statistically significant differences between the two groups for postoperative ventilation time, transfusion rate, ICU stay or length of hospital stay were recorded. At the end of follow-up, 98.5 % vs. 96.9 % of the patients were free of thromboembolism (p = n. s.), 100.0 % vs. 96.9 % were free of endocarditis (p = n. s.), and 98.5 % vs. 100.0 % were free of reoperation (p = n. s.) in group M compared to group C. Survival was 97.0 % vs. 91.9 % (p = ns). No differences in any of the 8 QOL categories, in patient satisfaction with the operative result or in judgment of the cosmetic aspect were noted among groups. CONCLUSIONS: This study has failed to show any advantage of minimally invasive AVR in early or midterm follow-up.

3D-video- and robot-assisted minimally invasive ASD closure using the Port-Access techniques.

BACKGROUND: Video-assisted minimally invasive surgical methods with endovascular-based femoral cardiopulmonary bypass (CPB) and balloon occlusion of the aorta (Port-Access technique) were used to close an ostium-secundum atrial septal defect (ASD) in 7 patients. METHODS: Minor modifications were made to the system to provide drainage of the superior vena cava. The surgery was performed through a small (3.5-5cm) right anterolateral thoracotomy with 3D video and robotic arm assistance. RESULTS: The operative procedures were completely uneventful and the patients were discharged four days postoperatively in good condition and with excellent cosmesis. CONCLUSION: Using the modifications described, the Port-Access surgical method can be recommended for minimally invasive closure of an ASD.

3D-visualization improves the dry-lab coronary anastomoses using the Zeus robotic system.

BACKGROUND: Robotic surgical instruments enable quick and precise movements and may allow complete endoscopic coronary artery bypass grafting. However, cardiac surgeons will have to become familiar with this technology and endoscopic viewing. We present our training program with special focus on 2D- and 3D-visualization. METHODS: A thoracic skeleton, covered with a neoprene suit, served as model for the chest wall. Either a glove, fixed on a metal plate, or a pig heart were placed inside for training. On the glove, a suture line consisting of two lines of 16 points each, with a distance of 2 mm between each point, was stamped. On the pig heart, the LAD was prepared and incised; subsequently an anastomosis was done using the dissected right coronary artery as a graft. The time required was measured for both models. For suturing, the Zeus System (Computer Motion, Goleta, CA) was used and the third robotic arm positioned the endoscopic camera. The scopes were connected to a 3D-camera and the picture was displayed on a headset with two integrated monitors. Visualization was set to either 2D or 3D. Three surgeons were involved in the study. Each one did at least 12 anastomoses on 2D and 3D. RESULTS: The three surgeons involved showed a clear and rapid learning curve. The times required for the suture line decreased from 12.5 +/- 1.6 to 8.5 +/- 0.5 minutes with 2D and from 11.9 +/- 5.4 to 7.8 +/- 0.5 minutes for 3D respectively. This decrease did reach statistical significance (p = 0.03). In the pig heart model, the anastomosis times decreased from 33.2 +/- 8.4 to 15.7 +/- 0.3 minutes with 3D-visualization, and from 36.2 +/- 2.2 to 29.5 +/- 3.3 minutes with 2D. The decrease in anastomosis time did again reach significance (p = 0.025). At the end of the study, the times achieved with 2D-visualization were significantly longer than those with 3D (p = 0.01). CONCLUSIONS: A surgical training program is mandatory to become familiar with these new technologies. Both models showed learning curves over an acceptable time course. 3D-visualization facilitated quick and precise movements, thus resulting in shorter anastomosis times.

Continuous transesophageal echocardiographic (TEE) monitoring during port-access cardiac surgery.

BACKGROUND: Since the introduction of the closed-chest minimally invasive heart surgery using the Port-Access system a variety of monitoring techniques including fluoroscopy, transesophageal echocardiography (TEE) and invasive pressure measurements have been described. We investigated whether or not single TEE is feasible for perioperative monitoring of the placement, localization and proper function of the endovascular cardiopulmonary bypass (CPB) devices. METHODS: Fifty-one patients (35 mitral valve repair or replacement [MVR], 8 coronary artery bypass grafting [CABG], 5 atrial septal defects [ASD] and 3 left atrial myxoma) were subjected to Port-Access surgery (PAS). Intraoperative Omniplane-TEE (2D- and color-flow Doppler techniques) was used as the leading monitoring device for correct positioning of the endopulmonary vent catheter and the venous cannula, and for the visualization of the guide wire and the endoaortic occlusion catheter (Endoclamp). After balloon inflation, its proper positioning and function during endo-aortic occlusion, sufficient delivery of cardioplegia into the coronary ostia, absence of leakage flow and adequate venting were controlled. Left and right radial artery catheters as well as aortic root pressure measurements served as controls. Additional fluoroscopy was used as standby device. RESULTS: In 46 patients (90.1%) sufficient perioperative monitoring was provided by single TEE. In five cases additional intermittent fluoroscopy was necessary for correct positioning of the guide wire (CABG) and the Endoclamp (three MVR and one ASD). Dislocation of the Endoclamp into the left ventricle was observed once but was successfully corrected by TEE guidance. Weaning from CPB and de-airing were easily guided with TEE. We did not observe balloon-mediated aortic injury or aortic valve dysfunction, and myocardial recovery from CPB was uneventful. All cases of MVRs showed sufficient results (68% without evidence of regurgitation, 32% showed residual mitral valve incompetence of less than grade II). Neither perivalvular leakage (MV-replacement) nor shunt- (residual ASD) flow were detectable. CONCLUSIONS: We recommend single TEE as a safe and effective on-line imaging device for monitoring the endovascular CPB system during PAS. Fluoroscopy with its potential risk for the patients and the staff due to x-ray exposure should only be used in the presence of peripheral vascular disease or when echocardiographic imaging is insufficient.

Contrast-enhanced magnetic resonance angiography for control of minimally invasive coronary artery bypass conduits (MIDCAB/OPCAB).

OBJECTIVE: The purpose of this study was to delineate the course and determine the patency of venous and arterial conduits in the early postoperative period following minimally invasive bypass grafting. A less invasive magnetic resonance angiogram was evaluated as alternative to standard contrast angiography and cardiac catheterization. METHODS: Twelve patients (8 males and 4 females) with a mean age of 65.3 (+/- 7.4 ) years were evaluated four to seven days following minimally invasive direct coronary artery bypass surgery (MIDCAB) or off-pump multivessel revascularization with the Octopus stabilizer on the beating heart. Altogether 17 coronary bypass grafts were investigated: 12 left-sided mammary artery grafts to the LAD and five aortocoronary venous bypass grafts. The examination was performed with a 1.5 Tesla Magnetom Vision (Siemens AG, Erlangen) with phased array coil technology. Data acquisition was done with an ultrafast 3D gradient-echosequence in single breathhold and sagittal and coronal views. Contrast enhancement of the vessels was performed with automatic intravenous bolus injection of Gadolinium-DTPA after determination of the individual contrast transit time. Traditional contrast angiography was obtained in all patients during the same time period as a comparison to assess the sensitivity and specificity of the magnetic resonance imaging. RESULTS: All five venous grafts and 11 of the 12 IMA grafts were detected and shown to be patent with the MRA technique. Contrast angiography demonstrated complete patency for all 17 bypass grafts with adequate anastomoses and no evidence of stenosis. The calculated sensitivity for the visualization with MRA was therefore 92% for IMA grafts and 100% for venous grafts. CONCLUSION: The contrast-enhanced ultrafast MRA in single breathhold technique is a reliable, noninvasive method for visualization and determination of the patency of arterial and venous coronary grafts.