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Biomedical subjects

C T Ducko

Publications and source records attributed to C T Ducko.

13 recordsLinked to original sources
PubMed2001

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.

Aged↗
PubMed2000

Potassium channel openers: are they effective as pretreatment or additives to cardioplegia?

BACKGROUND: This study was designed to test the hypothesis that the potassium channel opener pinacidil (Pin) as a pretreatment (PT) agent or additive to St. Thomas' solution (StT) could enhance myocardial protection. METHODS: In a parabiotic rabbit Langendorff model, 36 hearts underwent global normothermic ischemia (1 hour) followed by reperfusion (30 minutes). Cardioplegia (50 mL, every 20 minutes) consisted of: StT; PinPT/StT, where Pin PT preceded StT arrest; Pin alone; Pin in StT (Pin/StT); and Pin in low potassium StT. Systolic function after reperfusion (percent recovery of developed pressure) and compliance (diastolic slope from pressure-volume relationship) were measured. RESULTS: There was no significant difference between StT and PinPT/StT in percent recovery of developed pressure (51.54% +/- 3.5%, 42.17% +/- 4.0%, respectively) or compliance. Likewise, no significant differences occurred between Pin, StT, Pin/StT, and Pin in low potassium StT in percent recovery of developed pressure (58.99% +/- 4.8%, 51.54% +/- 3.5%, 53.09% +/- 3.2%, 66.43% +/- 7.3%, respectively) or compliance. CONCLUSIONS: Pin is as effective a cardioplegic agent as StT; however, its use as a pretreatment or additive to traditional and Pin in low potassium StT provided no additional benefit in functional recovery.

Animals↗
PubMed2000

Mechanisms responsible for cell volume regulation during hyperkalemic cardioplegic arrest.

BACKGROUND: Cardioplegia has been shown to induce significant cell swelling. This study tested the hypothesis that (1) the [K+][Cl-] product of the cardioplegia solution is the main determinant of myocyte swelling, and (2) reperfusion myocyte shrinkage results from a rectifying Cl- conductance. METHODS: Rabbit ventricular myocytes were superfused with 37 degrees C Krebs-Henseleit solution for 10 minutes. Then cells underwent 20 minutes of superfusion with standard St. Thomas' solution ([K+][Cl-] product = 2566 mmol/L2) and two solutions with lower [K+][Cl-] product (1500 and 700 mmol/L2) at 9 degrees C. Cells were then resuperfused with 37 degrees C Krebs-Henseleit solution for 30 minutes. Cell volume was measured by videomicroscopy. RESULTS: Cells superfused with St. Thomas' having [K+][Cl-] products of 2,566, 1,500, and 700 mmol/L2 swelled by 9.18%+/-3.57%, 5.51%+/-1.08%, and 1.49%+/-1.56%, respectively. Reexposure to Krebs-Henseleit solution caused these cells to shrink by 5.79%+/-1.41%, 8.72% +/-3.68%, and 13.46%+/-5.60%, respectively. This shrinkage was blocked by Cl- channel blockers given at the onset of superfusion. CONCLUSIONS: Lowering the [K+][Cl-] product of St. Thomas' solution attenuated myocyte edema. Myocyte shrinkage during reexposure to Krebs-Henseleit solution resulted from the volume-activated Cl- channel.

Animals↗
PubMed2000

Initial United States clinical trial of robotically assisted endoscopic coronary artery bypass grafting.

OBJECTIVES: With traditional instruments, endoscopic coronary artery bypass grafting has not been possible. This study was designed to determine the clinical feasibility of using a robotically assisted microsurgical system to create endoscopic coronary anastomoses. METHODS AND RESULTS: Ten patients underwent endoscopic coronary artery bypass grafting of the left internal thoracic artery to the left anterior descending artery. Subxiphoid endoscopic ports (2 for instruments, 1 for a camera) were placed, and a robotic system was used to perform the left internal thoracic artery-left anterior descending artery bypass graft. Conventional techniques were used to perform the other grafts. Blood flow through the left internal thoracic artery graft was measured in the operating room and was adequate in 8 of 10 patients. The 2 inadequate grafts were revised successfully by hand. Six weeks after the operation, selective coronary angiography demonstrated a graft patency of 100% (8/8). There were no technical failures of the robotic system. The only postoperative complication was mediastinal hemorrhage in 1 patient. CONCLUSIONS: This pilot study demonstrates the feasibility of robotically assisted endoscopic coronary artery bypass grafting.

Anastomosis, Surgical↗
PubMed2000

Donor heart preservation with the potassium channel opener pinacidil: comparison with University of Wisconsin and St. Thomas' solution.

BACKGROUND: Hyperpolarized arrest with the potassium channel opener pinacidil has been shown to provide effective myocardial protection during short-term global ischemia. This study tested the hypothesis that pinacidil may provide effective long-term protection for heart transplant preservation. METHODS: Four concentrations of pinacidil (50 microM, 100 microM, 0.5 mM, 1.0 mM) mixed in Krebs-Henseleit solution were compared with University of Wisconsin and St. Thomas' Hospital solutions in a Krebs-Henseleit perfused rabbit Langendorff model (n = 6 for each group). Hearts underwent 4 hours of hypothermic (4 degrees C) storage. Over a wide range of volumes, left ventricular systolic function, diastolic compliance, and coronary flow were measured prior to and following storage. Time to mechanical and electrical arrest, and post-ischemic percent tissue water were also measured. RESULTS: Pinacidil 0.5 mM provided the best preservation of post-ischemic systolic function and coronary flow compared with the other pinacidil concentrations and was statistically equivalent to St. Thomas' solution in terms of post-ischemic systolic, diastolic, and flow properties. However, hearts protected with University of Wisconsin solution had significantly better preservation of systolic function and coronary flow. CONCLUSIONS: This investigation demonstrated that pinacidil in Krebs-Henseleit solution possesses efficacy in long-term donor heart preservation. Pinacidil was equivalent to St. Thomas' solution but inferior to University of Wisconsin solution. Hyperpolarized arrest with potassium channel openers may be a novel strategy to improve donor heart preservation.

Adenosine↗
PubMed1999

Computer-assisted endoscopic coronary artery bypass anastomoses: a chronic animal study.

BACKGROUND: With traditional instruments, endoscopic coronary artery bypass grafting (ECABG) has not been possible. This study was designed to determine the feasibility of using a robotically-assisted microsurgical system to perform ECABG in a chronic animal model. METHODS: Nine calves were placed on cardiopulmonary bypass after harvesting the left internal mammary artery (LIMA). Subxiphoid endoscopic ports (2 instrument, 1 camera) were placed, and a robotic system was used to perform ECABG between the LIMA and left anterior descending coronary artery. LIMA graft flow (LIMAQ) was measured. Animals were sacrificed at 1 month, and hearts underwent angiographic and histologic analyses. RESULTS: Acute graft patency was 89% (8/9). Two animals died suddenly within the first 48 hours. There was no significant difference in mean acute and chronic (n = 6) LIMAQ (40.9+/-4.7 and 38.5+/-5.0 ml/min, respectively). Survivors had an angiographic patency rate of 100% (6/6), confirmed by histology. CONCLUSIONS: This study shows that ECABG is feasible in a chronic animal model with excellent results.

Anastomosis, Surgical↗
PubMed1999

Robotically-assisted coronary artery bypass surgery: moving toward a completely endoscopic procedure.

BACKGROUND: Endoscopic coronary artery bypass grafting (ECABG) has not been possible with traditional techniques. This report details our animal experience determining the feasibility of using a robotically-assisted microsurgical system to perform ECABG. METHODS: Following preliminary work using a cadaveric pig heart model, acute and chronic animal studies were performed. Calves were placed on cardiopulmonary bypass after the left internal mammary artery (LIMA) was harvested. Subxiphoid endoscopic ports (2 instrument, 1 camera) were placed and a robotic system was used to perform ECABG between the LIMA and left anterior descending coronary artery. LIMA graft flow (LIMAQ) was measured, and excised hearts underwent angiographic and histologic analyses. RESULTS: All anastomoses were successfully completed in both the acute and chronic studies (mean time of 33.9 +/- 1.9 and 33.2 +/- 3.4 minutes, respectively). Angiographic patency was 100% in both the acute (8/8) and chronic (6/6) studies, which was confirmed by histology. In the chronic study, there was no difference in LIMAQ between intraoperative and autopsy measurements. CONCLUSIONS: This study shows that ECABG is feasible in an animal model with excellent results. The FDA has recently given approval for clinical trials of this new technology.

Animals↗
PubMed1999

Computer-assisted endoscopic coronary artery bypass grafting: the penn state experience.

The introduction and widespread acceptance of minimally invasive techniques have revolutionized surgical practice in many disciplines over the last two decades. Endoscopic operations have been shown to reduce patient morbidity and provide a more rapid return to work. Until recently, endoscopic approaches have had little impact on the field of cardiac surgery. Endoscopically-sutured coronary anastomoses have not been possible with conventional endoscopic instruments, due in part to their length and imprecision.

Journal Article↗
PubMed1998

Robotically assisted microsurgery for endoscopic coronary artery bypass grafting.

BACKGROUND: As minimally invasive approaches to cardiac surgery have expanded, a significant number of limitations have become apparent, particularly the lack of adequate precision with standard endoscopic instruments. We hypothesized that the use of robotics would eliminate some of these limitations. METHODS: Twenty-five coronary anastomoses on an isolated porcine heart, using an arterial conduit to the left anterior descending artery, were performed endoscopically with a microsurgical robotic system. Sophisticated robotic engineering was used to control modified endoscopic instruments under direct surgeon control. Computer tremor elimination and motion scaling allowed for precise maneuvering. An arteriotomy was placed in the left anterior descending artery, and an arterial conduit was positioned for anastomosis. The camera and port sites were placed 90 degrees from the long axis of the arteriotomy. A 7-0 Prolene (Ethicon, Somerville, NJ) suture was used to perform the anastomosis in a continuous fashion, begun at the 12 o'clock position and continued counterclockwise. After completion of half of the anastomosis, the conduits were pulled down and the final sutures were placed. The sutures were tied intracorporeally and the procedure was completed. RESULTS: The 25 conduits were successfully completed and showed good probe patency. Average time for completion of the anastomosis was 31.7 +/- 2.0 minutes. Appropriate port placement and orientation, and stabilization of the conduits were critical. The lack of tremor and motion scaling allowed for the precise movements needed to complete an endoscopic microvascular anastomosis. CONCLUSIONS: Coronary artery anastomoses are technically feasible with use of robotic instrumentation. This technology may enable the development of a truly endoscopic approach to bypass surgery.

Anastomosis, Surgical↗
PubMed1994

The effect of valve type and drive line dP/dt on hemolysis in the pneumatic ventricular assist device.

The objective of this experiment was to investigate the relationship between blood damage and drive line dP/dt and valve type in the pneumatic ventricular assist device. Two mock circulatory loops were assembled using 70-ml Penn State pneumatic ventricular assist devices, one fitted with convexo-concave (CC) valves and one fitted with monostrut (MS) valves. Use of a compliance chamber established three ranges of drive line dP/dt values. Using bovine blood and the methods of generalized estimating equations, it was found that drive line dP/dt was significantly associated with the index of hemolysis (p = 0.00): the lower drive line dP/dt values yielded lower indices of hemolysis. In addition, this association differed between MS and CC valves (p = 0.01); the MS valves consistently yielded a higher index of hemolysis than the CC valves across all drive line dP/dt ranges. However, the relative hemolytic potential of each valve type became much closer at low drive line dP/dt values (2,000-3,000 mm Hg).

Animals↗
PubMedDate not supplied

Robotically assisted coronary artery bypass grafting: a prospective single center clinical trial.

AIM: This prospective study was performed as a Phase 1 Food and Drug Administration clinical trial to assess the safety and feasibility of robotically assisted coronary artery bypass grafting (CABG). METHODS: Eighteen patients undergoing elective CABG were enrolled in this study. Full sternotomy was performed in 17 of 18 patients, while cardiopulmonary bypass and cardioplegic arrest was used in all cases. Robotically assisted CABG of the left internal thoracic artery (LITA) to the left anterior descending artery (LAD) was performed through three ports using a robotically assisted microsurgical system. Conventional techniques were used to perform all other grafts. Blood flow in the LITA graft was measured in the operating room, and when necessary, angiography was performed. Six weeks after the operation, all patients underwent selective coronary angiography of the LITA graft. RESULTS: Robotically assisted coronary artery anastomoses were successfully completed in all patients. Blood flow through the LITA graft was adequate in 16 of 18 patients (89%). The two inadequate grafts were revised successfully by hand. Six weeks after the operation, angiography demonstrated a graft patency of 100% (13 of 13). Mean follow-up has been over 190 days. All patients remain New York Heart Association Angina Class I. CONCLUSION: Robotic assistance represents an enabling technology that may allow the surgeon to perform endoscopic coronary artery anastomoses. Further clinical trials are needed to explore the clinical potential and value of robotically assisted CABG.

Coronary Artery Bypass↗