Case report: osteogenesis imperfecta, internal mammary artery graft & nitinol clips.

BACKGROUND: Osteogenesis imperfecta is a genetic disorder of connective tissue causing mostly left-sided heart valves and aortic root pathologies, but a coronary artery involvement reflecting an increased sensitivity to cardiovascular risk factors is also suspected in this patient population. CASE PRESENTATION: We report a 38-year-old patient with an osteogenesis imperfecta and a typical presentation of an acute myocardial infarction. The coronary angiogram showed a coronary 3-vessel disease. The patient underwent a bypass grafting surgery with the internal mammary artery. The sternum was closed using four nitinol clips and had totally stabilized at 4 months with excellent bone healing. CONCLUSIONS: With the successful clinical outcome in this patient severely affected by its osteogensis imperfecta, we underline the safe use of the LIMA, if precaution is taken towards the sternal bone, and its closure with nitinol clips.

A Novel Robotic Bilateral Internal Mammary Artery Harvest Using Double Docking Technique for Coronary Artery Bypass Grafting.

da Vinci Surgical System (da Vinci) enabled port access for internal mammary arteries (IMA) harvesting. However, bilateral IMA (BIMA) harvesting is difficult when performed on single side. We developed a novel technique of double docking the da Vinci by transpositioning from the left side to the right and examined the feasibility. Twelve patients underwent BIMA harvesting using the double-docking technique. First, the da Vinci was set on the patient's left side for the right IMA harvesting. Afterward, the da Vinci was undocked and transpositioned from the patient's left side to the right side. The time elapsed during rotation was measured. Subsequently, the left IMA was harvested from patient's right side. Distal anastomoses were performed by a small anterolateral thoracotomy. All of the IMAs were harvested and then bypassed without damage. The mean ± SD time that elapsed during rotation was 6.5 ± 0.6 minutes. There was no conversion to sternotomy. Bilateral IMA harvesting by the bilateral docking technique was performed successfully with acceptable feasibility.

Right Internal Mammary Artery Use in 140 Robotic Totally Endoscopic Coronary Bypass Cases: Toward Multiarterial Grafting.

OBJECTIVE: Benefits of adding a second arterial graft in coronary bypass are well documented. In patients requiring mulitvessel grafting robotic totally endoscopic coronary bypass (TECAB) has allowed for routine harvesting and use of the right internal mammary artery (RIMA). We retrospectively reviewed the technical considerations and target choice in 140 cases of beating heart TECAB where a RIMA graft was used. METHODS: In 2008, we introduced beating heart TECAB with anastomotic connectors into our practice, first with single IMA and then with bilateral internal mammary artery. A robotic stabilizer was used not only to facilitate exposure of the coronary targets but also to aid the RIMA harvest using a skeletonized approach. Flow measurements were obtained routinely. We reviewed the technical aspects, target choice, and intraoperative flows in our TECAB patients who underwent grafting with RIMA grafts. RESULTS: From February 2008 to January 2015, a total of 404 patients underwent beating heart TECAB with anastomotic connectors, of which 194 (48%) were mulitvessel procedures. One hundred forty patients (35%) had a RIMA graft and constitute the patient population for this review. One hundred thirty-one RIMA grafts were harvested via left-sided ports and grafted to left coronary targets, and nine RIMA grafts were harvested via right-sided ports and grafted to the right coronary artery. Flow was greater than 25 mL/min (pulsatility index < 2) in 95% of grafts. Perioperative mortality was 0.7% and mean ± standard deviation length of hospital stay was 3.1 (1.5) days. The RIMA was used as an in situ graft in 124 cases (84%) and as a free T-graft in 24 cases (16%) cases. Right internal mammary artery graft use in all TECABS increased from 23% in the first 5 years to 53% in the last 2 years. CONCLUSIONS: Robotic TECAB allows the routine harvesting and use of the RIMA graft in a safe and reproducible manner. Skeletonization and sternal sparing allow the RIMA to reach various coronary targets. Further studies are needed for this approach to impact the adaption of multiarterial grafting.

Minimally invasive direct coronary artery bypass grafting with an improved rib spreader and a new-shaped cardiac stabilizer: results of 200 consecutive cases in a single institution.

BACKGROUND: Performing minimally invasive direct coronary artery bypass (MIDCAB) grafting via small chest incisions on a beating heart is challenging. We report our experiences of MIDCAB with the utilization of both an improved rib spreader to harvest the left internal mammary artery (LIMA) and a new-shaped cardiac stabilizer to facilitate LIMA-left anterior descending (LAD) coronary anastomosis. METHODS: Between May 2012 and June 2104, a total of 200 patients who were consecutively operated on in this period were enrolled in this study. Data reported included demographic information, preoperative clinical and cardiac status, LIMA harvest time, postoperative in-hospital outcomes, and 30-day mortality. RESULTS: The average LIMA harvest time was 43 min. The mean age was 62.59 ± 10.19 years, and 45 of the 200 were females. The 30-day mortality was 0.5% (one patient) due to perioperative myocardial infarction. Duration of mechanical ventilation and length of stay in intensive care unit was 9.27 ± 7.65 and 24.27 ± 17.85 h, respectively. The unit of packed RBC transfusion was 0.79 ± 1.58. Postoperative atrial fibrillation was observed in 14 (7%) patients. There was no postoperative stroke, renal failure, or incision complication. CONCLUSION: Performing MIDCAB with the improved retractor and stabilizer utilized in this study showed favorable outcomes in terms of harvesting the LIMA, postoperative morbidities, and 30-day mortality.

Interrupted nitinol U-Clips versus standard running suture for the central arterial T-graft anastomosis: a prospective randomized study.

OBJECTIVES: Studies carried out to date suggest that the interrupted suture technique using U-Clips for anastomoses in coronary surgery may be superior to the standard running polypropylene suture. The purpose of this study was to compare safety and effectiveness of a central T-graft anastomosis constructed with the left internal thoracic artery (LITA) in situ (to the left anterior descending (LAD)) in which the free right internal thoracic artery (to the circumflex branch of the right coronary artery (RCX)) was implanted (RITA-to-LITA) using either self-closing nitinol U-Clips or simple continuous suture. We hypothesized that internal thoracic arteries could adapt their diameter to the blood flow. METHODS: Thirty patients underwent total arterial revascularization using a T-graft constructed with free LITA in situ to LAD in which the free RITA to the circumflex artery was implanted (central T-graft anastomosis). In all cases, free RITA was used as a sequential graft with two peripheral anastomoses. Patients were randomly assigned to two groups: in group A (n=15), central T-graft anastomosis was performed using a standard 8/0 polypropylene running suture. In group B (n=15), central T-graft anastomosis was performed using U-Clips. Intra-operative transit time flow measurements were recorded. Patency control was performed in 30 patients 2 weeks and 6 months postoperatively, using 64-slice computed tomography (CT) angiography. The diameter of the LITA was measured proximal and distal and the diameter of the RITA distal to the central T-graft anastomosis. RESULTS: Perioperative results were similar in the two groups (P=ns). Intra-operative transit time flow measurement showed patent grafts in all patients. There were no hospital deaths. Two weeks postoperatively, all grafts were patent. At 6-month follow-up, one RITA and one LITA (both in group B) were closed distal to the central T-graft anastomosis. There was no death and no re-intervention during follow-up. Statistical analysis showed no significant changes in graft diameters after 2 weeks and 6 months in both groups. CONCLUSIONS: The U-Clip anastomosis technique is in our experience safe but not superior to the standard running suture using polypropylene material. Remodeling of the ITA grafts close to the central T-graft anastomosis was neither observed for the standard running suture nor for the U-Clip anastomoses.

Robotic total endoscopic coronary artery bypass hybrid revascularization procedure in a patient with a preoperative tracheostoma.

Preoperative tracheostoma presents a significant risk of sternal wound complications, mediastinitis, stoma necrosis and tracheal injury in patients requiring cardiac surgery. Several approaches have been described to limit these risks. Robotic totally endoscopic coronary artery bypass grafting in patients with a tracheostoma has not been reported. We describe a case of completely endoscopic coronary surgery using the daVinci(®) Si™ system in a patient with a tracheostoma. Single left internal mammary artery grafting to the left coronary artery system was carried out successfully as the first stage of a hybrid revascularization and followed by percutaneous coronary intervention to the circumflex coronary artery. We regard this technique as the most minimally-invasive method of surgical coronary revascularization with a significant potential to reduce the risk of mediastinitis in patients with a tracheostoma.

Role of prosthetic conduits in coronary artery bypass grafting.

Prosthetic grafts are required for coronary artery bypass grafting (CABG) when the availability of suitable autologous conduits is limited. The ideal cardiovascular bypass graft requires a broad range of characteristics including strength, viscoelasticity, biocompatibility, blood compatibility and biostability. Many alternative conduits have been developed and used in the past, but most of them have failed, except in rare instances. This review aims to analyse the current status of their use and prospects for the future. We performed a literature search on PubMed using the generic terms 'conduits for coronary artery bypass grafting'; 'reoperative coronary artery bypass grafting'; 'redo coronary artery bypass grafting'; 'PTFE'; 'Dacron or PET'; 'gastroepiploic artery'; 'inferior epigastric artery'; 'biological grafts'; 'tissue-engineered grafts'; 'synthetic grafts'; 'prosthetic grafts'; 'polyurethane grafts'; 'cephalic veins'; 'short saphenous vein;' and 'alternative conduits'. In addition, we searched through related citations and references from selected articles. A total of 1253 references and 110 full-text articles were reviewed, and they were further selected based on available information. This review concludes that, over the past three to four decades, achieving the goal of a prosthetic graft with equivalent function and durability to the internal mammary artery or long saphenous vein has proved to be elusive.

Enabling technology for minimally invasive coronary artery bypass grafting.

Over the past 8 years, new techniques and perhaps more significantly new technology have expanded the possibilities for minimally invasive coronary artery bypass grafting. In this section, we review 3 important and potentially enabling technologies: (1) robotics, (2) anastomotic connectors, and (3) the expanding role of imaging in the context of combined operating room/catheterization laboratories (hybrid suites).

[Heart positioners and proximal anastomotic devices in off-pump coronary artery bypass grafting].

Owing to development of device technology, off-pump coronary artery bypass grafting (OPCAB) has become a safe, reproducible and reliable procedure. Surgeons must understand the advantages and limitations of each device and select appropriate devices in individual case to avoid device-related complication and a waste of cost. The directions and pitfalls of heart positioners, stabilizers and proximal anastomotic devices were described. With the improved heart positioners and stabilizers all coronary targets have been well visualized and accessible, maintaining hemodynamic stability. Automated proximal anastomotic devices and proximal anastomotic assist devices have reduced the occurrence of cerebral complications compared with the side-clamp of the ascending aorta. The appropriate use of devices in OPCAB would be a promising and cost-effective procedure for revascularization of ischemic heart disease.

Hybrid coronary artery bypass grafting.

Owing to the high prevalence of atherosclerotic coronary artery disease, treatment has proceeded along three separate paths: medical, surgical, and percutaneous intervention. Medical treatment is now routinely combined with both surgical treatment and percutaneous methods; however, the surgical and percutaneous routes are often viewed as in competition. Hybrid coronary revascularization, also called robotic assisted integrated coronary revascularization (RAICER), is a way of combining these two approaches. Whether any hybrid procedure will prove beneficial to patients remains unproven; however, RAICER has promise for reducing short-term complications while providing excellent and enduring treatment for coronary artery disease. Much work remains to be done on the benefits of hybrid revascularization in comparison with conventional bypass surgery or percutaneous coronary procedures.

Use of the Amplatzer Vascular Plug for treatment of coronary steal.

The left internal mammary artery (LIMA) is a widely used conduit during coronary artery bypass graft surgery because of its excellent long-term patency. Although large LIMA side branches are typically ligated during the surgery, the occurrence of a coronary steal phenomenon related to these side branches following surgery remains controversial. A variety of devices, including coil embolization and gelatin sponge particles, have been used in the percutaneous treatment of LIMA side branch induced coronary steal. The Amplatzer Vascular Plug has recently been applied in variety of clinical situations, including the occlusion of aortopulmonary collaterals, patent ductus arteriosus and pulmonary arteriovenous malformations. The Amplatzer Vascular Plug is a self-expandable, cylindrical device made from nitinol that offers several potential advantages in this setting including ease of delivery, a wide range of device sizes and the ability to safely remove the device if placement location in not optimal. In this case report, we present a patient with objective ischemia in the left anterior descending artery distribution secondary to coronary steal from a large LIMA side branch that was successfully treated using the Amplatzer Vascular Plug.

Left mini-thoracotomy off-pump coronary revascularization.

OBJECTIVES: Stent restenosis is a common complication in angioplasty. Studies have shown better outcomes when the left internal thoracic artery (LITA) is anastomosed to the left anterior descending artery (LAD). Patient selection, operative technique and results for off-pump left mini-thoracotomy (LME) coronary surgery, as a pilot study, are presented. METHODS: Eighteen patients (three women) with a mean age of 56.6 +/- 9.2 were operated on through a 9-14 cm LME to perform off-pump LITA to LAD anastomoses (14 patients) or diagonalis (DI) and LAD sequential anastomoses (4 men). The grafts were skeletonized during dissection and anastomoses were performed using 7-0 polypropylene running sutures. An access device (CardioThoracic Systems) allowed approach and coronary stabilization. RESULTS: There were no deaths, conversion to sternotomy, transfusions or high enzyme levels. All patients were released from hospital on the 3rd to 5th postoperative days and returned to their day-to-day activities within 30 days. One woman was readmitted for angina, presented with graft occlusion, and a stent was implanted and one man was readmitted for wound infection. Future angiography was performed on six patients and showed patent grafts. CONCLUSION: The operation was performed with low morbid-mortality, short hospital stays and without transfusions. Appropriate instruments and the ability of the surgeon to use his left hand, made this operation technically easy. Randomized studies may prove if there are sufficient clinical and economic benefits over the long term to make this surgery the first choice.

Detection of coronary arteries and evaluation of anastomoses with a commercially available 15-MHz, broadband, linear array transducer.

BACKGROUND: In coronary artery bypass surgery the detection of the target vessels can be difficult due to their intramural location, coverage by adipose tissue, calcification, or fibrous tissue formation. Their identification is especially critical during off-pump coronary artery bypass (OPCAB) and minimally invasive direct coronary artery bypass (MIDCAB) surgeries. Our objectives were to identify whether (1) the epimyocardial use of the broadband linear array transducer CL15-7 allows a clear and rapid identification of the target artery during on-pump coronary bypass (CPB), OPCAB and MIDCAB surgeries; and (2) if this transducer is helpful in investigating the anastomotic morphology with 2D and color flow Doppler. METHODS: Thirty-two patients without a visually identifiable left anterior descending artery (LAD) were included in the study and epimyocardial ultrasonography was performed. Stabilization of the beating heart was used in 19 patients; in 13 patients, the surgery was carried out with CPB on the arrested heart. Two-dimensional ultrasound alone, or in combination with color Doppler, was used to identify the affected vessel as well as a suitable anastomosis site. Pulsed wave Doppler had to be used occasionally to differentiate between artery and vein. Patency of the anastomoses was established with color Doppler immediately after reinitiating blood flow. An evaluation of the distal graft diameter, its length, and the quality of the anastomosis was made with 2D and color Doppler. Transit-time Doppler flow was used to confirm patency. RESULTS: The LAD could be identified ultrasonographically in all 32 patients at a depth of 3 to 15 mm. The right coronary artery (RCA) was located at a depth of 3 to 10 mm in the 5 patients where this vessel was to be bypassed. The coronary arteries located on the lateral or posterior aspect of the heart could not be reached due to the shape and rigidity of the transducer handle. The intended anastomosis sites of the LAD and RCA were identified with ultrasound according to their topography and morphology. In all cases the vessel could be dissected and bypassed without undue damage or bleeding. In one OPCAB patient, the LAD was identified in close proximity to the overlying vein along the whole of the anterior wall. This resulted in conversion to CPB, thus facilitating secure exposure of the LAD. The ultrasonographic visibility of the left internal mammary artery to LAD and saphenous vein graft to RCA anastomoses was excellent, and patency correlated well with the transit time flow measurements. CONCLUSION: The CL15-7 transducer gives excellent near field visibility of the LAD and RCA. This is extremely valuable for the safe dissection of these vessels, especially during off-pump coronary surgery. The anatomical morphology of the anastomoses can be identified but, due to the shape of the transducer handle, only the coronary arteries on the anterior surface of the heart can be evaluated. A flexible, rather than a rigid, hockey stick-shaped handle would eliminate this problem. Training is essential to obtain reliable results.

MRI-based safety evaluation of the ventrica magnetic coronary anastomotic system.

The Ventrica Magnetic Vascular Positioner system is a novel automatic anastomotic coupling device for distal coronary artery anastomosis. There is concern that enormous magnetic fields may negatively affect graft anastomosis or coronary artery blood flow, or that they may lead to disconnection of the magnetic ports. Forty-five domestic swine (26.6 +/- 5.9 kg) underwent magnetic resonance imaging after a single Ventrica anastomosis of the left internal mammary artery to the left anterior descending artery. Group A (n = 15) underwent magnetic resonance imaging immediately after surgery, group B (n = 15) was studied after 1 week, and group C (n = 15) after 2 weeks. The animals were sacrificed and the anastomotic sites were examined. All animals survived the imaging procedure. Mean imaging time was 25 +/- 6 min. Although imaging artifacts occurred in the area surrounding the Ventrica port, there were no disconnections or electrocardiographic signs of ischemia during the study period. Upon sacrifice, all anastomoses were patent without alterations in the alignment of the magnetic components. Clinically relevant tests such as cranial magnetic resonance imaging may be safe after use of the Ventrica system for coronary artery revascularization.

Totally endoscopic coronary artery bypass surgery.

Robotically enhanced surgery is a fast-developing technique that allows totally endoscopic cardiac surgery on both the beating and arrested heart. Between December 2002 and May 2005, 13 patients underwent totally endoscopic coronary bypass using the da Vinci system; 11 operations were on a beating heart and 2 on arrested hearts. The mean time for internal mammary artery mobilization was 42 min. The time for left internal mammary artery-to-left anterior descending artery anastomosis was 20-36 min for totally endoscopic cases. In one patient, the right internal mammary artery was anastomosed to the diagonal artery. No patient required conversion to a median sternotomy. Mean intensive care unit stay was 1.2 days and mean hospital stay was 4.5 days. There was no hospital mortality. All 13 patients had coronary angiography at 3-month intervals, which showed 100% patency in 12 patients while one had 50% anastomotic narrowing for which coronary angioplasty was performed. Using robotic technology, completely endoscopic anastomosis is possible in patients with single-vessel disease. Use of robotics is now extended to achieve complete myocardial revascularization by harvesting both internal mammary arteries in addition to making a small thoracotomy for direct anastomosis.

S2 connector versus suture: distal coronary anastomosis remodeling, patency, and function in the pig.

BACKGROUND: Anastomotic connectors could be the key to less invasive bypass surgery, including endoscopic procedures, but equivalence to conventional suturing needs to be established. A novel distal coronary connector was tested pre-clinically for safety and efficacy in comparison to conventional suturing. METHODS AND RESULTS: Left internal thoracic to left anterior descending coronary artery bypasses were constructed off-pump in 35 pigs (73+/-8 kg). An intraluminal metal connector (S2AS) was used in 21 and conventional suturing in 14 animals. S2AS anastomosis construction was easier achieved in one-fourth of the conventional construction time (3.7+/-0.7 versus 16.5+/-2.6 minutes; P<0.001). Acute patency tended to be better (P=0.15). All anastomoses were evaluated intraoperatively, and subgroups at 90 and at 180 days. Patency was 100%. An effective remodeling response was observed in all groups, resulting in unobstructed anastomoses with excellent hemodynamic performance (fractional flow reserve > or = 0.93 at 180 days). At 6 months, the noncompliant connector was covered with stabilized neointima that was thinner than found on the suture line (0.10+/-0.04 versus 0.31+/-0.13 mm; P=0.01). The connector induced less lumen loss (-0.6+/-6.5 versus 21.6+/-19%; P=0.03). The initial side-to-side configuration had remodeled to an end-to-side shape as intended. CONCLUSIONS: In the porcine model, the connector rapidly and consistently produced high-quality anastomoses that fully met current standards on patency and function. Unconventional aspects like a noncompliant intraluminal ring and a side-to-side to end-to-side converted configuration did not interfere with favorable anastomosis remodeling. These findings shed a new light on the anatomical prerequisites for anastomosis patency.

Internal thoracic artery to left anterior descending anastomosis performed on the beating heart by endoscopic robot assistance using a new distal connector.

BACKGROUND: Automated distal connecting devices have been recently introduced to facilitate coronary anastomosis. This could have a large impact on the capacity of robotic systems to perform completely endoscopic off-pump bypass, where the quality of anastomosis and the prolonged operative time for the performance of the anastomosis have until now been cause for concern. Our group tried to determine the feasibility and efficacy of the JoMed distal graft connector using the ZEUS robotic system. METHODS: Six swine, with a mean weight of 25.8 (standard deviation [SD] 2.2) kg, underwent endoscopic off-pump internal thoracic artery-left anterior descending (ITA-LAD) anastomosis with a special stabilizing system using ZEUS robotic assistance. The anastomosis was performed with the JoMed distal connector. RESULTS: The connector was employed successfully in 4 of 6 cases using a special delivery instrument. Two animals fibrillated within 2 minutes after the application of proximal occluding snares and were excluded from the analysis. The total device deployment time was 2 minutes 4 seconds (SD 50 s) in 4 of 6 survivors, which remained hemodynamically stable and in sinus rhythm until euthanasia. Coronary angiography and transonic flow measurements were used to verify patency. CONCLUSION: The JoMed distal graft connector may facilitate the use of robot-assisted endoscopic bypass on a beating heart. Long-term patency issues will need to be assessed.

Quality of anastomosis in conventional on-pump coronary artery bypass graft surgery: influence of the interrupted technique using u-clips and correlation with intraoperative graft flow patterns.

BACKGROUND: The interrupted suture technique in creating graft-coronary artery anastomoses in coronary artery bypass graft (CABG) surgery is hypothesized to be superior to the standard continuous technique. However, because of the increased time and knot tying involved with the interrupted technique, the continuous suture became standard. In 2000, the U-clip (a self-closing metal clip) was introduced to help in creating an interrupted anastomosis, although data regarding its clinical use are still somewhat limited. Intraop-erative transit-time flow measurement (TTFM) of blood flow through an anastomosis is frequently used to assess quality of anastomosis creation; mean flow and pulsatile index (PI) are analyzed. PI should typically be between 1 and 5; higher values are associated with errors of anastomosis creation. The current study analyzes the difference in TTFM between U-clips and standard suture in CABG surgery. METHODS: The study population consists of 30 prospectively enrolled patients undergoing first-time on-pump conventional CABG surgery at St. Anthony Medical Center who were randomized to have their anastomosis created with either U-clips or suture. TTFM were recorded for left internal mammary artery to left anterior descending artery (LIMA-LAD) anastomoses. RESULTS: Of the 30 subjects enrolled (10 women), 12 operations were done with U-clips and 18 with suture. Body mass index (BMI) in the 2 groups was similar. In terms of mean flow, there was no difference between the 2 groups (29.8 +/- 18.4 mL/min for U-clips versus 26.6 +/- 11.0 mL/min for suture, P = .57). In terms of PI, again no difference was found (3.1 +/- 1.3 for U-clips versus 2.5 +/- 0.8 for suture, P = .12). CONCLUSIONS: The findings of this study suggest that U-clips are comparable to the standard suture for LIMA-LAD anastomoses in conventional on-pump CABG surgery in terms of intraoperative assessment of graft flow.

Percutaneous repair of a left internal mammary graft entrapped under sternal wires.

Injury to a left internal mammary artery (LIMA) bypass graft is a known complication of repeat cardiothoracic surgical intervention. This report details the percutaneous intervention to an entrapped LIMA graft to the left anterior descending artery (LAD).