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Biomedical subjects

P F Gründeman

Publications and source records attributed to P F Gründeman.

At least 19 recordsLinked to original sources
PubMed2004

Endoscopic robot-assisted extended thymectomy by subxiphoid approach with sternal lifting: feasibility in the pig.

BACKGROUND: In the search for novel approaches to thoracoscopic thymectomy we assessed the feasibility of a subxiphoid approach using computer-enhanced instruments and sternal lifting. METHODS: In 12 pigs, after lifting of the sternum, ports were placed subxiphoid (stereoscope) and in the left and right fourth intercostal space (instruments). Using computer-enhanced instruments, dissection of the thymus and anterior mediastinal fat pads was started at the diaphragm and continued cephalad. RESULTS: After setup of the robot system (23 +/- 6 min, mean +/- SD), the thymus, including both superior horns, and fat pads in the anterior mediastinum and cardiophrenic angles were dissected (109 +/- 23 min), with excellent view of the phrenic nerves. Visual inspection after sternotomy after the procedure showed all thymic and fatty tissue was removed. CONCLUSIONS: In the pig, endoscopic extended thymectomy can be safely performed by subxiphoid access using computer-enhanced instruments, sternal lifting, and three ports total.

Animals↗
PubMed2001

Hemodynamic changes with right lateral decubitus body positioning in the tilted porcine heart.

BACKGROUND: In beating-heart coronary surgical procedures, exposure of posterior vessels through sternotomy causes cardiac function to deteriorate. We hypothesized that turning the subject to the right lateral decubitus position before cardiac retraction improves exposure of posterior vessels and preserves cardiac pump function on displacement. METHODS: Eight 80-kg open-chest pigs were instrumented with catheter-tip manometers. After a stepwise 60-degree turn to the right lateral decubitus position of the body, the heart was retracted anteriorly to 90 degrees with a suction stabilizer. RESULTS: Right lateral body positioning caused an approximately 45-degree right deviation of the apex, thereby exposing the left atrial groove. Stroke volume, mean arterial pressure, right atrial pressure, and right ventricular end-diastolic pressure increased to 106% +/- 5% (mean +/- standard error of the mean, p = 0.31), 106% +/- 3% (p = 0.01), 129% +/- 8% (p = 0.001), and 171% +/- 14% (p = 0.002), respectively, compared with control values. In contrast, left atrial pressure decreased to 73% +/- 6% (p = 0.007), whereas left ventricular preload remained unchanged (110% +/- 8%, p = 0.26). Additional anterior displacement to 90 degrees fully exposed the posterior vessels, and stroke volume decreased to 90% +/- 3% (p = 0.01) and mean arterial pressure to 93% +/- 5% (p = 0.07) at the expense of further increased right ventricular preload (256% +/- 28%, p < 0.001). CONCLUSIONS: By placing the subject in the right lateral decubitus position, exposure through sternotomy of posterior vessels in the beating porcine heart was facilitated while mean arterial pressure was maintained.

Animals↗
PubMed2000

Arteriotomy closure by glued patch in the porcine carotid artery.

BACKGROUND: A thoracoscopic approach to coronary bypass grafting warrants renewed search for facilitated vascular anastomosis methods. We reassessed tissue adhesion, sealing properties, and histotoxicity of iso-butyl-cyanoacrylate, in a simplified anastomosis model. METHODS: In 12 Dutch landrace pigs, five arteriotomies were made in each carotid artery. The arteriotomies were closed by conventional microvascular suturing or by pericardial patch (Peri-Strips) and iso-butyl-cyanoacrylate. The animals were sacrificed at 2 hours (n = 2), 2 days (n = 5), and 4 weeks (n = 5). The arteries were examined by flow measurement, angiography, and histologic analysis. RESULTS: The time required to close arteriotomies by conventional suturing was 257 +/- 43 seconds (mean +/- SD) and by glued patch 51 +/- 27 seconds (p < 0.001). In all arteriotomies covered by glued patch, complete hemostasis was obtained. At 2 days and 4 weeks, with both methods the same histologic results were observed. At follow-up, all carotid arteries were patent without stenoses. CONCLUSIONS: Arteriotomy closure by glued patch was simple, fast, reliable, and without signs of histotoxicity. Adhesives deserve to be reconsidered as an alternative to suturing in closed chest beating-heart coronary surgery.

Anastomosis, Surgical↗
PubMed1999

Temporary luminal arteriotomy seal: III. Postmortem arteriosclerotic human coronary artery.

BACKGROUND: Recently, we described a temporary luminal arteriotomy seal that provided a bloodless arteriotomy without obstructing recipient artery blood flow during bypass grafting in nonarteriosclerotic porcine arteries. This postmortem study assessed the sealing properties in irregular arteriosclerotic human coronary arteries. METHODS: Three hearts were obtained from donated corpses within 24 hours of death. The coronary arteries were pressure-perfused at 60 mm Hg with citrated porcine blood. At 15 anastomosis sites in four different coronary arteries, an end-to-side anastomosis was created using a 200-microm-thick polyurethane seal. Adequacy of sealing was determined at perfusion pressures of 60, 40, and 20 mm Hg. RESULTS: After insertion, the arteriotomy was sealed instantaneously in 10 of 15 anastomoses. After repositioning, complete sealing with a bloodless operative field was obtained in all cases. Low intracoronary transmural pressure did not impede sealing. In 8 of 15 anastomoses, minor leakage without obscuring the arteriotomy edges was observed during anastomotic suturing. Histologic examination revealed no intimal tear or dissection caused by the anastomotic procedure. CONCLUSIONS: In postmortem-obtained arteriosclerotic human coronary arteries, the temporary luminal arteriotomy seal provided optimal visualization of the coronary anastomosis site in combination with persistent distal perfusion.

Aged↗
PubMed1999

Exposure of circumflex branches in the tilted, beating porcine heart: echocardiographic evidence of right ventricular deformation and the effect of right or left heart bypass.

OBJECTIVE: In off-pump coronary surgery, exposure of posterior vessels via sternotomy causes deterioration of cardiac function. Changes in ventricular geometry, valve competence, and hemodynamics after retraction of the beating heart were studied. Subsequently, the modifying effect of right or left heart bypass was investigated. METHODS: In six 80-kg pigs, an ultrasound probe was attached to the backside of the left ventricle and the heart was fully retracted with a suction tissue stabilizer. Five pigs underwent additional pump support. RESULTS: During retraction, the right ventricle was squeezed between the pericardium and interventricular septum, thereby decreasing its diastolic cross-sectional area by 62% +/- 6% (P <.001) while, concomitantly, right ventricular end-diastolic pressure increased to 165% +/- 19% (P =.004) of basal values. Stroke volume and mean arterial pressure decreased by 29% +/- 6% and 23% +/- 8% (P =.007 and P =.02, respectively). Left ventricular shape became somewhat elliptic without changes in preload pressure, and its diastolic cross-sectional area decreased by 20% +/- 3% (P =.001). All valves were competent. Right heart bypass restored left ventricular cross-sectional area, stroke volume, and mean arterial pressure. In contrast, left heart bypass increased blood pressure only marginally. CONCLUSIONS: Ninety-degree anterior displacement of the beating porcine heart caused primarily right ventricular dysfunction as a result of mechanical interference with diastolic expansion without concurring valvular incompetence. Right heart bypass normalized stroke volume and mean arterial pressure by increasing left ventricular preload; in contrast, left heart bypass failed to restore systemic circulation.

Animals↗
PubMed1999

A novel one-shot anastomotic stapler prototype for coronary bypass grafting on the beating heart: feasibility in the pig.

OBJECTIVE: The nonpenetrating, arcuate-legged clip has proved its ability to provide a high-quality microvascular anastomosis. This study assessed the feasibility of constructing a coronary end-to-side anastomosis on the beating heart with a novel mechanical, sutureless anastomotic device that applies 12 circumferential clips simultaneously. METHODS: In 14 consecutive pigs (70-90 kg), the left internal thoracic artery (diameter, 3 mm) was grafted to the left anterior descending coronary artery (diameter, 3 mm) by means of a one-shot anastomotic stapler prototype. Endothelial denudation, medial necrosis, and intimal hyperplasia were analyzed quantitatively and compared with those seen in conventionally sutured anastomoses (n = 4). RESULTS: In 8 of 14 anastomoses, the one-shot anastomotic stapler successfully applied all 12 clips circumferentially across the everted arteriotomy edges. In the remaining, either 1 (n = 4) or 3 and 4 adjoining malaligned clips had to be replaced manually with a single-clip applicator. Coronary occlusion was limited to approximately 3 minutes. At follow-up, all anastomoses were patent angiographically. At 2 days, in 2 of 7 cases, a local coronary dissection was observed, and there was a considerable loss of endothelial cells and medial damage. At 28 days, however, minimal intimal hyperplasia was seen at the anastomotic lining, although more pronounced when compared with conventionally sutured anastomoses. CONCLUSIONS: The one-shot anastomotic stapler prototype enabled short-occlusive (3 minutes), sutureless end-to-side grafting on the beating porcine heart. In spite of early endothelial and medial damage and 2 local dissections, all anastomoses remained patent with minimal intimal hyperplasia at 4 weeks.

Anastomosis, Surgical↗
PubMed1998

Intima-adventitia apposition in end-to-side arterial anastomosis: an experimental study in the pig.

BACKGROUND: To prevent ischemic complications during coronary bypass grafting on the beating heart, a nonocclusive distal anastomosis technique is needed. One recently developed nonocclusive technique requires apposition of the intima of the graft to the adventitia of the recipient artery, in contrast to current surgical practice, which dictates apposition of both intimas. METHODS: To compare the sole effect of intima-adventitia apposition (n = 18) versus traditional intima-intima apposition (n = 18), we investigated radiolabeled platelet deposition and histomorphologic aspects of vascular wall healing quantitatively in a porcine carotid artery bypass graft model. Both groups were evaluated at 2 hours, 2 days, or 4 weeks. RESULTS: Within the first 2 hours, 3 of 6 pigs with intima-adventitia apposition exhibited cyclic flow reductions as a result of massive mural thrombosis. After intima-adventitia apposition, the number of deposited platelets was significantly higher compared with intima-intima apposition, 147.1 +/- 73.0 x 10(6) and 4.6 +/- 1.0 x 10(6) platelets/cm2 (mean +/- standard error of the mean), respectively (p = 0.03). At 2 days, the suture line was covered with small mural thrombi, whereas no thrombi were found after intima-intima apposition. At 4 weeks, intimal hyperplasia at heel and toe was not significantly different from that with intima-intima apposition. CONCLUSIONS: Despite thrombotic phenomena in the early phase, intima-adventitia apposition yielded a patent anastomosis with a small intimal hyperplasia response.

Anastomosis, Surgical↗
PubMed1998

Temporary luminal arteriotomy seal for bypass grafting.

BACKGROUND: To enable off-pump coronary operations in a bloodless surgical field without ischemic complications, we developed and assessed a temporary luminal arteriotomy seal in a porcine carotid artery bypass graft model. METHODS: In 16 consecutive pigs (25 kg, 32 anastomoses) the arteriotomy was sealed luminally by a polyurethane elliptic convex seal. Endothelial denudation, medial necrosis, and intimal hyperplasia were measured quantitatively and compared with those seen in conventionally sutured anastomoses. RESULTS: The median occlusive time upon insertion or retrieval was 90 and 82 seconds, including the arteriotomy and securing the anastomosis, respectively. Once properly positioned, the seal provided a bloodless arteriotomy in all anastomoses. Microsurgical suturing was performed without leakage of the seal and with unimpeded flow. In the recipient artery, endothelial denudation was limited to one third of its circumference. No medial necrosis was found. Intimal hyperplasia at heel and toe was not significantly different from that seen in conventionally sutured anastomoses. CONCLUSIONS: During end-to-side bypass grafting, the temporary luminal arteriotomy seal provided a bloodless surgical field without interfering with recipient artery blood flow and with minimal damage to the arterial wall.

Anastomosis, Surgical↗
PubMed1998

Vertical displacement of the beating heart by the octopus tissue stabilizer: influence on coronary flow.

BACKGROUND: In beating heart coronary artery bypass graft operations, biventricular pump failure, as observed after exposure of the posterior circumflex branches by sternotomy, may originate from mechanical obstruction to coronary flow. METHODS: Regional coronary blood flow was measured in 8 anesthetized, paced, beta-blocked pigs, and the beating heart was fully retracted. RESULTS: Displacement decreased cardiac output from 4.8 +/- 1.1 L/min (mean +/- standard deviation) to 2.8 +/- 1.2 L/min (p < 0.001), a 42% +/- 6% decrease that resulted in a decrease in mean arterial pressure by 48% +/- 6% (mean +/- standard error of the mean; p < 0.001) and a reduction in coronary blood flow in the left anterior descending coronary artery, the right coronary artery, and the circumflex coronary artery by 34% +/- 6%, 25% +/- 8%, and 50% +/- 10%, respectively (all p < 0.05 versus baseline). Relative circumflex coronary artery flow was 20.1% +/- 8.3% lower than the combined relative value of left anterior descending coronary artery and right coronary artery flows (p = 0.046). Subsequent 20 degrees head-down tilt significantly increased ventricular preload pressures and restored cardiac output and mean arterial pressure as well as coronary blood flow. CONCLUSIONS: It is inferred that coronary blood flow was not mechanically obstructed during anterior displacement of the porcine beating heart, because augmentation of preloads by the maneuver of Trendelenburg restored coronary flow parallel to the recovery of cardiac output and mean arterial pressure while the heart remained retracted by 90 degrees.

Animals↗
PubMed1998

Temporary luminal arteriotomy seal: II. Coronary artery bypass grafting on the beating heart.

BACKGROUND: This study assessed the feasibility of applying a temporary luminal arteriotomy seal during end-to-side coronary artery bypass grafting on the beating heart. METHODS: In 18 consecutive pigs, the left internal mammary artery was grafted to the left anterior descending coronary artery, and the arteriotomy was temporarily sealed luminally by a 200-microm-thick polyurethane seal. Endothelial denudation, medial necrosis, and intimal hyperplasia were measured quantitatively and compared with conventionally sutured anastomoses (n=4 pigs). RESULTS: Insertion and retrieval of the seal required 28+/-12 and 11+/-6 seconds, respectively. Including the arteriotomy, coronary artery occlusion was limited to about 80 seconds. The seal provided a bloodless arteriotomy in all anastomoses with unimpeded coronary artery blood flow. Endothelial denudation was limited to two thirds of the circumference of the coronary artery. No medial necrosis was found. Intimal hyperplasia at the suture line was small, although more pronounced when compared with conventionally sutured anastomoses. CONCLUSIONS: In off-pump, beating-heart coronary artery bypass grafting, the temporary luminal arteriotomy seal provided a bloodless arteriotomy with negligible obstruction to coronary artery blood flow, and with a minimum of arterial wall damage. It is conceivable that this seal may expand the indications for coronary surgical procedures without cardiopulmonary bypass.

Animals↗
PubMed1998

Off-pump coronary bypass grafting: how to use the Octopus Tissue Stabilizer.

Off-pump coronary artery bypass grafting requires immobilization of the coronary artery. A suction device (Octopus Tissue Stabilizer), attached to the epicardium and connected rigidly to the operating table rail, was used through limited and full surgical access for single-vessel and multivessel arterial revascularization, respectively. An outline for its application, as used by us to construct 122 anastomoses in 70 patients, including posterior wall grafting (in 9 patients) and sequential grafting on the anterior wall (in 17 patients), is presented.

Anastomosis, Surgical↗
PubMed1998

Coronary artery bypass grafting without cardiopulmonary bypass using the octopus method: results in the first one hundred patients.

OBJECTIVE: Cardiopulmonary bypass and global cardiac arrest enable safe coronary artery bypass grafting but have adverse effects. In off-pump coronary bypass grafting, invasiveness is reduced, but anastomosis suturing is jeopardized by cardiac motion. Therefore the key to successful off-pump coronary bypass grafting is effective local cardiac wall stabilization. METHODS: We prospectively assessed the safety and efficacy of the Octopus tissue stabilizer (Medtronic, Inc., Minneapolis, Minn.) in the first 100 patients selected for off-pump coronary bypass via full or limited surgical access. To immobilize and expose the coronary artery, two suction paddles (-400 mm Hg), fixed to the operating table-rail by an articulating arm, stabilized the anastomosis site. RESULTS: One hundred forty-one grafts (96% arterial) were used to create 172 anastomoses (17% side-to-side), up to 4 per patient, on average 23 in the full access group (46 patients) and 1.2 in the limited access group (54 patients). Complications included conversion to cardiopulmonary bypass (2%), conversion from limited to full access (3%), myocardial infarction (4%), predischarge coronary reintervention (2%), and late coronary reintervention (1%). Median postoperative length of hospital stay was 4 days (limited access) or 5 days (full access). Rapid recovery allowed 96% of patients to resume social activities within 1 month. At the 6-month angiographic follow-up, 95% of anastomoses was patent. At the 2- to 22-month follow-up (mean, 13 months), 98 patients were in Canadian Cardiovascular Society class I and 2 patients were in class II. CONCLUSION: These results suggest that off-pump coronary artery bypass grafting with the Octopus tissue stabilizer is safe. Early clinical outcome and patency rates warrant a randomized study comparing this methods with conventional coronary bypass grafting.

Cardiopulmonary Bypass↗
PubMed1997

[Minimally invasive arterial coronary bypass grafting: on beating heart and via smaller access].

Postoperative recovery after (arterial) coronary bypass grafting mostly takes several months because of the effects of the heart-lung machine and the cardioplegia which are mostly haematological, pneumological and neurological in nature. The morbidity can be reduced by operating on the beating heart and via smaller access. One possibility is the 'Octopus' method developed in Utrecht, which involves local fixation of the beating heart. The postoperative recovery of the first 45 patients was favourable.

Anastomosis, Surgical↗
PubMed1997

Hemodynamic changes during displacement of the beating heart by the Utrecht Octopus method.

BACKGROUND: Coronary bypass grafting of posterior circumflex branches requires full displacement of the heart (apex pointing ventrally), which, in the beating heart, results in an arterial pressure drop. We analyzed its origin. METHODS: To facilitate displacement, the Utrecht "Octopus" method was applied in 8 anesthetized beta-blocked pigs and the beating heart was fully retracted. RESULTS: Displacement decreased stroke volume from 75 +/- 17 mL (mean +/- standard deviation) to 43 +/- 13 mL (p < 0.001), a 44% +/- 3% decrease that resulted in a decrease in cardiac output by 32% +/- 5% (mean +/- standard error of the mean; p < 0.001), a decrease in mean arterial pressure by 26% +/- 5% (p < 0.01), and an increase in heart rate by 26% +/- 6% (p < 0.01). Right ventricular end-diastolic pressure increased from 5 +/- 1 to 8 +/- 1 mm Hg (p < 0.01). Twenty degrees head-down tilt normalized cardiac output and mean arterial pressure. Right ventricular end-diastolic pressure increased to 10 +/- 2 mm Hg (p < 0.001) and left ventricular end-diastolic pressure to 11 +/- 3 mm Hg (p < 0.01). CONCLUSIONS: Displacement of the beating heart in the pig induced a 44% drop in stroke volume, which is attributed to biventricular interference with pump function. The Trendelenburg maneuver reestablished the control circulatory status at the expense of augmented right and left ventricular preloads and an increased heart rate.

Animals↗