Epicardial Colour-Doppler Scanning of Coronary Artery Stenoses and Graft Anastomoses

Objective : Epicardial ultrasound scanning was applied during coronary surgery to assess coronary artery stenoses and quality of distal graft anastomoses, with special emphasis to the left anterior descending artery (LAD). Design : Twenty-three patients with coronary artery disease (M:F 19:4, mean age 65.0 &#45 9.5 years) had coronary artery bypass grafting (CABG) on cardiopulmonary bypass. Intraoperative scanning of coronary artery stenoses and graft anastomoses was performed with a new 10 MHz linear array Vingmed transducer connected to a GE Vingmed System FiVe echocardiography unit. Coronary stenoses detected by ultrasound were compared with preoperative angiograms. Intraoperatively, coronary graft flow was assessed with a Medi-Stim transit-time flowmeter. Results : Twenty LADs were investigated. In 17 LADs (85%) stenoses were clearly identified. In three LADs (15%) stenoses were not identified because LADs were deeply intramyocardial or the stenosis was very proximal. There was a significant correlation between LAD stenoses detected by ultrasound and angiogram ( R = 0.7; p < 0.01). Mean number of grafts was 3.8 &#45 0.9. Of 26 LAD anastomoses assessed, good images were obtained in 22 cases (84.4%); the mean LAD diameter measured 1 cm below the anastomosis was 1.6 &#45 0.2 mm. In two LADs images were rated fair and in two LADs images were poor because of intramyocardial LAD. No technical error of the anastomoses was detected. All grafts had good flows as ascertained by flow measurements. Conclusion : Epicardial ultrasound scanning with the new 10 MHz transducer allowed satisfactory imaging of coronary stenoses and graft anastomoses. Factors limiting the quality of imaging are proximal lesions, intramyocardial vessel, vessel tortuosity, and extensive calcifications. Epicardial ultrasound scanning with updated technology should become a further advancement to graft assessment during off-pump coronary surgery.     

Intraoperative color Doppler ultrasound assessment of LIMA-to-LAD anastomoses in off-pump coronary artery bypass grafting

BACKGROUND: Although techniques for off-pump coronary artery bypass grafting (CABG) are continually being refined, angiographic follow-up studies have indicated a higher rate of anastomoses-related stenoses than expected after traditional on-pump CABG. This study was performed to evaluate the use of intraoperative epicardial color Doppler ultrasound to quality-assess left internal mammary artery (LIMA) to left anterior descending coronary artery (LAD) anastomoses performed on the beating heart. METHODS: Twenty-four LIMA-to-LAD anastomoses were evaluated with real-time epicardial ultrasound imaging using an ultrasound transducer positioned between the paddles of the stabilizer during off-pump procedures. The length of the anastomosis (D(A)), diameters of LIMA (D(M)), LAD at the toe of the anastomosis (D1), and 5 mm distally to the anastomosis (D2) were measured, and the ratios between these variables were calculated. The flow velocity through the anastomoses was visualized by color Doppler coding, and flow was assessed with transit-time flowmetry. RESULTS: The epicardial color Doppler ultrasound allowed accurate assessment of the anastomoses. Twenty-three (96%) of the primary anastomoses were confirmed as patent. Mean ratios of D1/D2, D(A)/D2, and D(M)/D2 were 0.89 +/- 0.13, 3.01 +/- 1.04 and 1.32 +/- 0.32, respectively. One anastomosis had a stenosis more than 50% detected by color Doppler ultrasound. After surgical revision, transit-time flow increased from 22 to 40 ml/min. CONCLUSIONS: Intraoperative color Doppler ultrasound allowed adequate imaging for quality assessment of LIMA-to-LAD anastomoses performed on the beating heart. One anastomosis was revised due to a technical error detected by epicardial color Doppler imaging. Epicardial ultrasound scanning is a valuable tool for intraoperative assessment of LIMA-to-LAD anastomoses during off-pump coronary surgery.     

Assessment of left mammary artery grafts (LIMA) to left anterior descending artery (LAD) after off-pump coronary artery bypass grafting by color Doppler.

BACKGROUND: Off-pump coronary artery bypass grafting (OPCAB) on a beating heart with a LIMA graft to the LAD is established for patients with one vessel disease. The aim of the study was to assess the LIMA patency noninvasive by transcutaneous duplex ultrasound. METHODS: 25 patients (16 male, 9 female, mean age 58+/-13 yr) with LIMA grafts to LAD by OPCAB procedures were studied 7-20 days after surgery. Doppler velocity parameters were measured by use of a 7 MHz transducer placed in left intercostal space. The conventional coronary angiographies performed showed the LIMA graft patent. RESULTS: In all cases a typical biphasic pattern of blood flow was recorded with forward flow in both systole and diastole respectively. Under basal conditions the mean peak velocities in systole were 0.36 m/s and the mean peak velocities in diastole were 0.27 m/s with a mean systolic/diastolic ratio of 1.33. CONCLUSION: Transcutaneous Doppler ultrasound is useful in the detection of the LIMA graft flow. This non-invasive technique may find applications for routine postoperative follow-up of patients with LIMA grafts.     

Thermal coronary angiography: a method for assessing graft patency and coronary anatomy in coronary bypass surgery

Thermal coronary angiography was evaluated in 50 patients undergoing 137 saphenous vein and 48 internal mammary artery bypass grafts. A total of 177 thermal coronary angiograms were performed after completion of the distal anastomoses by injection of cold cardioplegia into the vein or by reperfusion with warmer blood in the internal mammary artery grafts. These angiograms provided details of graft and anastomosis patency, flow directions, and presence of native coronary stenoses. Temperature differences between the injectant and the epimyocardium of greater than 4 degrees C resulted in high-contrast images. Thermal coronary angiograms were obtained in 173 of the 177 studied bypass grafts; 172 grafts were patent, and 1 internal mammary artery graft was occluded. Unsuspected stenoses were detected at the site of four distal anastomoses. Subsequently, two anastomoses were successfully revised and three additional grafts performed. Ninety-six native coronary stenoses were located in the recipient coronary arteries. In ten instances, the thermal coronary angiograms were obscured by excess fat or myocardium, thereby impeding correct image analysis. We conclude that thermal coronary angiography can be clinically relevant and helps improve decision making during coronary artery bypass operations.     

Real-time patency control with thermal coronary angiography in 1401 coronary artery bypass grafting patients

Objective: Intraoperative coronary angiography has always been favoured by cardiac surgeons. Thermal coronary angiography (TCA) is a useful method for intraoperative control of graft patency. It detects heat differences between tissues, provides easy-to-interpret angiographic images and even measures the flow of the grafts quantitatively. Methods: Between January 2000 and January 2002, TCA has been used in scheduled coronary bypass operations. Upon completion of each distal anastomosis, the perfusion of the distal arterial tree from the graft was evaluated with a thermal camera. Results: TCA was applied to 1401 patients, mean age 60.97±9.61 years, who underwent simple coronary artery bypass grafting (CABG) procedures. A total of 4105 thermal images were obtained including 2161 venous, 1355 single internal thoracic artery (ITA), 56 bilateral ITA and 477 radial artery grafts. Image quality was not sufficient in 34 grafts (1.57%) due to either deep intramyocardial vessels or excessive epicardial fat tissue. Technical failures in three ITA anastomoses were detected and revised before the cross-clamp was removed. Flow-restricting lesions distal to the anastomosis on the left anterior descending artery (LAD) in nine patients were managed with a secondary distal bypass graft (five patients) or plaque splitting and anastomotic revision (four patients). Endarterectomy was combined in seven patients since the graft flow and the distal visualization was not satisfactory, although the anastomoses were performed on a good lumen. Angiographically undetected diagonal arteries were revascularized in 11 patients with totally occluded LAD vessels. Conclusion: Thermal imaging provides decisive coronary angiographies, and detects the perfusion area and flow of the implanted graft. It allows real-time detection of technical failures, reveals unexpected occluding plaques or any kind of flow-restricting lesions, and gives the chance of refinement of the anastomosis during the arrest period. We believe that the thermal imaging technique is a safe, noninvasive and feasible method to document the quality of the myocardial revascularization intraoperatively.     

IMA-graft patency control by thermal coronary angiography during coronary bypass surgery.

Thermal coronary angiography (TCA) was evaluated for the intraoperative assessment of graft patency and flow in internal mammary artery (IMA) bypass grafts. TCA was performed in 210 patients undergoing 460 vein and 153 IMA bypass grafts after completion of the distal anastomoses. The IMA grafts and the recipient coronary arteries were delineated by the temperature differential between a cold epimyocardium and the perfusing warm blood after bulldog clamp release. TCA provided information about graft and anastomosis patency, initial flow patterns, and native coronary stenoses. TCA was performed in all studied IMA bypass grafts: 142 grafts were patent. Low flow but patency was observed in 24 IMA grafts and 11 IMA grafts showed no flow. Subsequently, 8 anastomotic failures and 3 proximal IMA graft occlusions were encountered. Based on these findings, 8 anastomoses were successfully revised and 7 additional vein grafts were added. One low flow IMA graft was not revised leading to postoperative ST elevation. Thirty-one distal native coronary stenoses were detected in the recipient LADs, 3 of which were not seen in the preoperative cineangiogram. In 20 instances, TCAs were obscured by an excess of fat or myocardium impeding image analysis. In 8 cases, TCA results were confirmed by conventional angiography postoperatively showing an excellent correlation in all cases. We conclude that intraoperative TCA demonstrates early IMA graft function and initial flow patterns. During our study, TCA documented a 7.2% IMA graft early failure rate. Intraoperative decision making was aided by TCA in 9.2% of all IMA grafts; this confirmed the clinical relevance of TCA.     

Quality assessment of distal SAS connector anastomosis by 13 MHz epicardial ultrasound

Objective: During application of a distal coronary bypass connector, we employed 13 MHz epicardial ultrasound to evaluate quantitative caliper measurements for vessel size matching and to assess anastomosis quality after connector deployment. Methods: Two S²AS connector anastomoses were constructed on ex vivo pressure-perfused porcine hearts. Epicardial ultrasound measurements of the connector ring and anastomosis were compared to intravascular ultrasound measurement and cast dimensions. In 21 pigs, anastomotic sites with internal diameter of 2.25–3.0 mm (internal mammary artery, IMA) and 1.8–2.2 mm (left anterior descending coronary artery, LAD) were selected using external caliper and epicardial ultrasound measurements. Anastomoses were visualized and assessed intraoperatively (beating heart, n = 21) and at 3 and 6 months’ follow-up (explanted heart, n = 10 each). Results: Epicardial ultrasound underestimated connector dimension by ≤5% versus intravascular ultrasound and deviated ≤13% from cast dimensions for other anastomotic measurements. Caliper estimates of internal IMA and LAD diameter differed from ultrasound by −3 ± 6% and −2 ± 7% (mean ± SD), respectively. Intraoperatively, the anastomotic orifice was flawless in all animals. It remained fully patent at 3 and 6 months by ultrasound, which was confirmed by histology. The connector to LAD percentage diameter stenosis changed from −12 ± 5% intraoperatively to −1 ± 7% at 3 months and from −5 ± 6% intraoperatively to −16 ± 13% at 6 months, in the growing pig model. Conclusions: In the pig, external caliper measurements provided a reliable quantitative estimate of inner graft and coronary diameter for connector size matching. Epicardial 13 MHz ultrasound is a promising method to assess coronary anastomosis quality even when connector metal is present.     

Patency of saphenous vein coronary artery bypass grafts from the vascular prosthesis of the ascending aorta.

BACKGROUND: Patients who have Stanford type A aortic dissection with impaired coronary arteries or who have aneurysms from the ascending aorta to the aortic arch with coronary artery disease need coronary artery bypass grafting (CABG) with tube graft replacement of the ascending aorta simultaneously. When vein grafts are used for CABG in these patients, the proximal anastomoses of vein grafts are attached to the prosthetic tube graft of the ascending aorta. However, the validity of proximal anastomoses of vein grafts to the prosthetic tube graft of the ascending aorta has not been confirmed. PATIENTS AND METHODS: We retrospectively analyzed patients who underwent venous coronary bypass grafting with prosthetic graft replacement of the ascending aorta. Between January 1984 and October 2002, 35 patients underwent CABG using saphenous vein grafts at the time of tube graft replacement of the ascending aorta, and the proximal anastomoses of the vein grafts were attached to the tube graft of the ascending aorta. Thirty-three venous bypass grafts were analyzed in 24 survivors. RESULTS: The postoperative catheterization showed only one early vein graft occlusion of 16 vein grafts anastomosed distally to the left anterior descending artery (LAD). All 14 venous grafts anastomosed to the right coronary artery (RCA) and 3 to the left circumflex artery (LCX) were patent. Therefore, the postoperative patency rate at discharge was 97.0% (32/33). Spiral computed tomography performed for long term follow-up revealed occlusion of two vein grafts (3.5 years and 9.7 years) anastomosed to the LAD. CONCLUSIONS: The patency rate of vein grafts anastomosed from prosthetic grafts of the ascending aorta to the native coronary arteries was similar to that of conventional CABG using saphenous vein grafts.     

Visualization of intramuscular left anterior descending coronary arteries during off-pump bypass surgery

In off-pump coronary artery bypass surgery, an appropriate method for intraoperative evaluation of grafts and vessels has been awaited. We report the usefulness of a 15-MHz linear transducer for this purpose. A 15-MHz linear transducer with a SONOS 5500 (Philips Medical Systems, Best, Netherlands) was applied epicardially in off-pump coronary artery bypass surgery patients. Vascular anatomy was easily discerned when the transducer was applied in an appropriate way. In 6 patients, intramuscular coronary arteries were easily detected, and in all of these patients, anastomoses were successful. The shapes of the anastomoses were very clearly shown, and the flow and its phase in the bypass graft or coronary artery were measured with synchronization of electrocardiograms in all patients. The total left internal thoracic artery (LITA) flow (28.4 +/- 6.8 mL/s) and the pattern of the flow was dominantly diastolic in all patients. The 15-MHz linear transducer system (Philips) is very useful for detecting intramuscular left anterior descending coronary arteries and may become one of the standard tools for intraoperative evaluation in off-pump coronary artery bypass surgery.     

Reperfusion of the human myocardium by saphenous vein bypass grafts. Biochemical considerations

The adenine nucleotide content of the human myocardium in the distribution of the left anterior descending coronary artery (LAD) was measured before and after saphenous vein bypass grafting. The purpose of the study were twofold: (1) to relate the level of adenosine triphosphate (ATP) before bypass grafting to the percent stenoses of the LAD and (2) to determine the benefit or lack of benefit of bypass grafting on ATP content. Eighteen patients with angiographically determined LAD lesions of 40% to 100% underwent bypass grafting with standard cardiopulmonary bypass and cardioplegia. Transmural needle biopsy specimens were obtained from the center of the area perfused by the LAD immediately before cross-clamping of the aorta and 30 minutes after reperfusion of the myocardium via the native LAD and the graft. The tissue was divided into thirds: The endocardial and epicardial thirds were analyzed for ATP by high-pressure liquid chromatography and the middle third was viewed by light microscopy. The percent narrowing of the LAD correlated well (r = -0.71) with the ratio of ATP to total adenine nucleotides (TAN) in the endocardium. Epicardial ATP did not correlate with the percent stenoses of the LAD. The endocardial ATP/TAN ratio increased in the group as a whole from 0.51 +/- 0.27 (mean +/- SD) to 0.64 +/- 0.26 (p less than 0.01) after bypass grafting, and this was most impressive in those eight patients with LAD lesions greater than 90% (0.32 +/- 0.20 before grafting to 0.60 +/- 0.29 after grafting, p less than 0.005). However, the epicardial ATP/TAN ratio decreased from 0.75 +/- 0.15 before grafting to 0.64 +/- 0.17 after grafting (p less than 0.05), and this decrease occurred regardless of the percent narrowing of the LAD. There was no difference in vacuolization between the pre-grafting and post-grafting biopsy specimens, and intramyocardial hemorrhage was not observed. This study has demonstrated a close relationship between the degree of LAD stenosis and endocardial ATP content. Also, the endocardium supplied by arteries with greater than 90% lesions had significantly increased ATP while the epicardium had decreased ATP content after bypass grafting.     

Off-pump coronary artery bypass grafting: long term angiographic results

OBJECTIVE: Although short-term results of off-pump coronary artery bypass grafting are well documented, late postoperative data are still scarce. This report provides an analysis of late postoperative control angiograms. METHODS: 265 patients (231 males, 34 females; mean age: 54 +/- 10) underwent postoperative angiographic control, after an average postoperative period of 4.2 +/- 2.3 years (up to 9 years, a total of 1110 years). A total of 385 distal anastomoses on 258 internal mammary arteries (IMAs) and 127 saphenous vein grafts (SVGs) were evaluated. The primary operation was single bypass in 156 cases (62%), double bypass in 98 (34%), and triple or more bypass in 11 (4%). RESULTS: Out of 258 IMAs, 241 were patent (93%), while SVG patency was 65% with 82 patent grafts out of 127 (p < 0.0001). The patency in the lateral branches (62%) and right coronary system (64%) were similar. The variables associated with graft occlusion were hypercholesterolemia (p = 0.02), poor left ventricular performance (p = 0.03), reoperation (p = 0.01), target coronary vessel caliber less than 1.5 mm (p < 0.0001), poor native coronary vessel quality (p = 0.0003) and low-grade stenosis (p = 0.02). In the poor left ventricle group, the left ventricular segmental wall motion score was improved (p = 0.004). Consequently, 47 patients underwent secondary revascularization (35 PTCA and 12 CABG). The leading indication was native coronary artery disease progression, frequently in the circumflex system, followed by graft failure. The cases with native vessel disease progression were referred to PTCA/stenting, while those with LAD graft occlusion were treated surgically. CONCLUSIONS: Probably the best candidates for OPCAB are those having target vessels of good caliber and quality, and high-grade stenoses. Postoperative lipid-lowering therapy seems to be prudential.     

Early clinical and angiographic outcome of the pedicled right internal thoracic artery graft to the left anterior descending artery

BACKGROUND: The left internal thoracic artery (LITA) graft to the left anterior descending (LAD) artery became the gold standard graft in coronary surgery. Subsequently, the right internal thoracic artery (RITA) graft was increasingly used. However, there is still some debate about the optimal way of using this conduit. The aim of the present study was to assess our experience in grafting the pedicled RITA graft to LAD in 212 consecutive patients. METHODS: The records of 212 consecutive patients who underwent isolated coronary artery bypass grafting with the pedicled RITA graft to the LAD artery at Harefield Hospital between January 1998 and May 2001 were retrospectively reviewed. We approached the last 35 consecutive patients to obtain an angiographic control group. All 35 patients (16.5%) consented and, before discharge, underwent angiography to look at the quality of anastomoses and the patency of grafts. RESULTS: Successful catheterization and engagement of the RITA grafts was performed in 32 patients. Angiography showed that 32/32 (100%) of the RITA grafts were widely patent with excellent flow. The distal anastomoses of these RITA grafts were also satisfactory. There were no deaths among the study patients. CONCLUSIONS: Our results show that the use of the pedicled RITA graft to the LAD artery provides a good early clinical and angiographic outcome, and suggests that the pedicled RITA graft to the LAD artery is a good alternative to the pedicled LITA graft to the LAD artery.     

Patency rates of three arterial grafting patterns to the left anterior descending and diagonal coronary arteries in symptomatic patients

BACKGROUND: The use of internal thoracic arteries is an established method for treating coronary artery disease because of their excellent long-term patency rates. However, these results mainly referred to the left internal thoracic artery (LITA) grafted to the left anterior descending coronary artery (LAD). The aim of this study was to compare the patency rate of the LITA after its placement to the diagonal branch. METHODS: A total of 302 patients (median age 65 years) with previous arterial revascularization were retrospectively enrolled in the study. We compared LITA grafts to the LAD with those to the diagonal branch and with sequential LITA grafts to both vessels with respect to the patency rate over a median follow-up of 39 months after prior operation. Angiography was performed for recurrent angina. RESULTS: The average occlusion/stenosis rate of saphenous vein and LITA grafts were 43.1% and 14.1%, respectively (p < 0.0001). Of the 302 patients, 248 had received a single LITA graft to the LAD; 21 patients, a single LITA graft to the diagonal branch; and 33 patients, a sequential LITA graft to both vessels. Thirty-three LITA grafts to the LAD (13.3%), three LITA grafts to the diagonal branch (14.3%), and six sequential LITA grafts to the LAD and the diagonal branch (18.2%) were occluded or stenosed more than 50%, respectively (p = 0.68). Seventy-nine percent of LITA graft stenoses were located at the peripheral anastomosis. CONCLUSIONS: Patency of single LITA grafts to the diagonal branch or sequential LITA grafts to the LAD and diagonal branch were comparable to single LITA grafts to the LAD. Most stenoses of LITA grafts were located at peripheral anastomoses.     

Triple coronary bypass in a child with homozygous familial hypercholesterolemia

Here we report triple coronary bypass procedure in a 12-year-old girl with familial homozygous hypercholesterolemia and extensive coronary atherosclerosis. She had successful cardiopulmonary resuscitation at home by her father 4 months before the operation. Total cholesterol level was 1300 mg/dL initially without antilipidemic treatment. Extensive three vessel disease with right coronary proximal stenosis and left coronary ostial stenoses was determined by angiography. Left internal thoracic artery, left radial artery, and saphenous vein grafts were used for coronary revascularization. Saphenous vein graft to right posterior descending artery, radial artery graft to obtuse marginal artery, and LITA to left anterior descending artery anastomoses were performed consecutively. Ten months after the operation, she is in good condition under intensive antilipidemic therapy and weekly lipid apheresis.     

Prospective clinical trial of robotically assisted endoscopic coronary grafting with 1-year follow-up

OBJECTIVE: To follow up in prospective fashion patients with coronary artery anastomoses completed endoscopically with robotic assistance. The robotic system was evaluated for safety and its effectiveness in completing microsurgical coronary anastomoses. SUMMARY BACKGROUND DATA: Recently there has been an interest in using robotics and computers to enhance the surgeon's ability to perform endoscopic cardiac surgery. This interest has stemmed from the rapid advancement of technology and the desire to make cardiac surgery less invasive. Using traditional endoscopic instruments, it has not been possible to perform coronary surgery. METHODS: Nineteen patients underwent robotically assisted endoscopic coronary artery bypass grafting of the left internal thoracic artery (LITA) to the left anterior descending artery (LAD). Two robotic instruments and one endoscopic camera were placed through three 5-mm ports. A robotic system was used to construct the LITA-LAD anastomosis. All other required grafts were completed by conventional techniques. RESULTS: Seventeen LITA-LAD grafts (89%) had adequate intraoperative flow. The mean LITA-LAD graft flow was 38.5 +/- 5 mL/min. At 8 weeks, LITA-LAD grafts were assessed by angiography and showed 100% patency with thrombolysis in myocardial infarction (TIMI) I flow. At a mean follow-up of 17 +/- 4.2 months, all patients were NYHA class I and there were no adverse cardiac events. CONCLUSIONS: The results from the first prospective clinical trial of robotically assisted endoscopic coronary bypass surgery in the United States showed favorable short-term outcomes with no adverse events. Robotic assistance is an enabling technology allowing the performance of endoscopic coronary anastomoses.     

High-frequency epicardial ultrasound: review of a multipurpose intraoperative tool for coronary surgery

Background  In open-chest coronary artery bypass grafting (CABG), the surgeon faces several intraoperative challenges: (1) to locate the target coronary artery, (2) to select the optimal anastomotic site, and (3) to assess the quality of the graft and distal anastomosis. Endoscopically, these three diagnostic aims are particularly challenging. Methods  We reviewed the literature on the intraoperative application of high-frequency (6.5–15 MHz) epicardial ultrasound (ECUS) in CABG to aid in these challenges. Results  Overall, ECUS was used in 628 patients to visualize and assess 912 (segments of) coronary arteries, as well as 418 grafts and distal anastomoses. In 96 cases, ECUS successfully located a coronary artery that was buried in the epicardial and/or myocardial tissue. In 37/155 (24%) imaged anastomotic sites, an alternative site free of pathology was selected. For quality assessment of the coronary anastomosis, experimental validation of ECUS included 218 anastomoses in ex vivo and animal models. ECUS showed high sensitivity (0.98) and specificity (1.00) for detection of anastomotic construction errors in 120 ex vivo anastomoses. In 418 grafts and distal anastomoses evaluated in patients, irregularities leading to revision were detected in 8 (1.9%) anastomoses and minor irregularities in an additional 23 (5.5%) anastomoses. However, little is known about the effect on long-term patency of specific anastomotic abnormalities revealed by ECUS. Scanning of arteries and anastomoses required several minutes. Current size ultrasound probes allowed successful experimental robot-assisted endoscopic application of ECUS. Conclusions  CABG may be facilitated and improved in several ways by intraoperative high-frequency epicardial ultrasound scanning. Totally endoscopic CABG may benefit from ultrasound diagnostics in particular.     

Alternative techniques for management of distal anastomoses of aortofemoral and iliofemoral endovascular grafts

PURPOSE: Techniques for managing the distal anastomoses of aortofemoral and iliofemoral endovascular grafts are described. METHODS: Over a 2(1/2)-year period 46 endovascular grafts were successfully placed to treat severe iliac artery occlusive disease. Endovascular grafts were anchored proximally in the distal aorta or iliac arteries with Palmaz balloon-expandable stents. The distal anastomoses were performed with the use of open, sutured anastomotic techniques. In contrast to stented distal anastomoses, these techniques allowed us to (1) treat occlusive lesions extending from the distal aorta to below the inguinal ligament, (2) terminate endovascular grafts in the groin where stents are contraindicated, (3) vary the distal anastomotic site depending on the local pattern of disease, and (4) standardize the preinsertion length of the endovascular graft. RESULTS: Two distal perianastomotic stenoses and one graft occlusion were detected postoperatively in 11 bypass grafts that had distal anastomoses sewn endoluminally without an overlying patch angioplasty. Only one perianastomotic stenosis was found among 35 anastomoses performed with other techniques. There were no significant differences in primary and secondary patency between grafts originating in the distal aorta or iliac arteries. CONCLUSIONS: Hand-sewn distal anastomoses can simplify the insertion of endovascular grafts used for the treatment of aortoiliac occlusive disease. These anastomoses permit tailoring of the graft according to the patients' pattern of disease and eliminate the need to precisely measure the length of the graft preoperatively. In addition, because a distal stent is not required, endovascular grafts can be safely terminated in the groin instead of the external iliac artery where disease progression can lead to graft failure. Finally, endovascular distal anastomoses should be closed with a patch or the hood of a more distal bypass graft to prevent perianastomotic stenoses or occlusions in the postoperative period.     

The Shelhigh No-React bovine internal mammary artery: a questionable alternative conduit in coronary bypass surgery?

BACKGROUND: Increasing age and comorbidities among patients undergoing coronary artery bypass surgery (CABG) stimulates the exhaustive research for alternative grafts. No-React treatment should render the tissue resistant against degeneration and reduce early inflammatory response. The aim of the present study was an invasive assessment of the patency of No-React bovine internal mammary artery (NRIMA grafts) used as bypass conduit in CABG surgery. PATIENTS AND METHODS: Nineteen NRIMA grafts were used in 17 patients (2.9%) out of a total of 572 patients undergoing CABG surgery within a 12-month period. All intraoperative data were assessed and in-hospital outcome was analysed. Follow-up examination was performed 7.0+/-4.0 months after initial surgery, including clinical status and coronary angiography to assess patency of the NRIMA grafts. RESULTS: Average perioperative flow of all NRIMA grafts was 71+/-60 ml/min. One patient died in hospital due to a multi-organ failure. Four patients refused invasive assessment. Follow-up was complete in 12 patients with overall 13 NRIMA grafts. Nine NRIMA grafts (69.2%) were used for the right coronary system, two NRIMA grafts (15.4%) on the LAD and two on the circumflex artery. Graft patency was 23.1% and was independent of the intraoperative flow measurement. CONCLUSIONS: NRIMA grafts show a very low patency and cannot be recommended as coronary bypass graft conduits. Patency was independent of the perioperative flow, assessed by Doppler ultrasound. Because of this unsatisfying observation, this type of graft should be utilised as a last resource conduit and used only to revascularise less important target vessels, such as the end branches of the right coronary artery.     

Off-pump redo coronary artery bypass grafting

BACKGROUND: Conventional redo coronary artery bypass grafting is associated with significant morbidity. The danger of reoperation is mainly in reopening the sternum and in the manipulation of the heart and the old grafts. Therefore, off-pump redo coronary artery bypass grafting with a patient-specific approach in selected cases seems an ideal technique. METHODS: Between October 1995 to September 1999, 50 patients with mean age of 61.8+/-8 years underwent reoperative coronary artery bypass grafting without cardiopulmonary bypass. Isolated left internal mammary artery (LIMA) to left anterior descending artery (LAD) anastomosis was carried out in 25 cases through left anterior minithoracotomy. In 1 patient LIMA was grafted on a previous vein graft to LAD, which was critically stenosed proximally but distal anastomosis was patent. In another case LIMA was grafted to Ramus intermedius branch. Midsternotomy approach was used to carry out LAD and right coronary artery grafting in 21 cases. In 2 patients a posterolateral thoracotomy approach was used to bypass obtuse marginal branches without cardiopulmonary bypass; in these cases proximal anastomosis was performed on the descending aorta. RESULTS: Mortality rate was 4% (2 deaths). Two patients sustained perioperative myocardial infarction. No patient was reexplored for hemorrhage and 38 patients did not require homologous blood transfusion. Sixteen patients underwent check angiogram and all of them were found to have patent redo grafts. Cardiac recovery room stay was 22+/-7 hours and hospital stay 5+/-2 days. CONCLUSIONS: In selected patients, reoperative coronary artery bypass grafting can be performed without cardiopulmonary bypass with a low perioperative morbidity and mortality and satisfactory graft patency.     

Robot-assisted 13 MHz epicardial ultrasound for endoscopic quality assessment of coronary anastomoses

In totally endoscopic coronary artery bypass surgery, intra-operative assessment of anastomotic quality is needed. We evaluated the endoscopic application of epicardial ultrasound to visualize the coronary anastomosis and detect a construction error. In 8 pigs (71-78kg), 16 internal mammary artery to left anterior descending coronary artery anastomoses were constructed conventionally, either correctly (n=8) or incorrectly with a suture cross-over construction error (n=8). A 13MHz mini-transducer (15x9x6mm) was introduced through a port and manipulated by the 'da Vinci' system. The chest was re-opened and scanning repeated manually. Postoperatively, macroscopic inspection served as reference and the intra-operative ultrasound images were scored as 'correct' or 'construction error' by two blinded observers. All anastomoses were scored accurately by both observers. One anastomosis constructed to be correct was scored as construction error, due to narrowing of the outflow corner and anastomotic orifice. Ultrasound images corresponded with macroscopic inspection. Closed-chest scan time was about 1.5 times longer than open-chest scan time, 176s (88-464) (median, range) versus 125s (75-314) (P=0.01), respectively. Closed-chest epicardial 13MHz ultrasound scanning required a median of 3min and enabled discrimination between correctly and incorrectly constructed coronary anastomoses.