Biomedical subjects

X M Mueller

Publications and source records attributed to X M Mueller.

At least 73 records · Page 4Linked to original sources

PubMed1998

Experimental evaluation of the Medtronic Maxima Forté hollow fiber membrane oxygenator.

A new hollow fiber membrane oxygenator, the Medtronic Maxima Forté, was tested for gas transfer, blood path resistance and blood handling characteristics in a standardized setting with surviving animals. Three calves (mean body weight: 71 +/- 9.6 kg) were placed on cardiopulmonary bypass at a mean flow rate of 50 ml/kg/min for six hours. The circuit included the Maxima Forté oxygenator. The animals were weaned from cardiopulmonary bypass and then from the ventilator. After seven days, the animals were sacrificed electively. Physiologic blood gas values could be maintained throughout perfusion in all animals. Mean pressure drop through the oxygenator varied between 49 mmHg and 66 mmHg. The respective baseline values for red blood cell count, white blood cell count and platelets were 8.90 +/- 1.26 10(6)/mm3, 7.46 +/- 3.17 10(3)/mm3. and 680 +/- 216 10(3)/mm3. Red blood cell and platelet counts dropped slightly to 7.26 +/- 1.61 10(6)/mm3 and 400 +/- 126 10(3)/mm3 at the end of the bypass, whereas the white blood cell count increased up to 9.13 +/- 5.25 10(3)/mm3. All three cell lines returned to near their baseline values after seven days. Blood trauma evaluated as a function of plasma hemoglobin (plasma Hb) and lactate dehydrogenase (LDH) showed stable values during all the perfusion time. Both peaked at 24 hours before returning to their baseline values at seven days. LDH showed a statistically significant variation: 3255 +/- 693 IU at 24 hours versus 2029 +/- 287 IU at baseline (p = 0.04). The variation of plasma Hb was not statistically significant (93.5 +/- 7.7 mumol/l at 24 hours versus 77.3 +/- 52.3 mumol/l at baseline) indicating a weak effect of the perfusion on blood trauma. The Medtronic Maxima Forté hollow fiber membrane oxygenator offered good gas exchange capabilities, a low pressure drop, and low blood trauma over a prolonged perfusion time of six hours in this evaluation.

Animals↗

PubMed1998

[Minimally invasive internal saphenous vein harvesting for coronary artery bypass].

Harvesting of the great saphenous vein for coronary artery bypass grafting is usually performed through long cutaneous incisions. We report our experience of minimally invasive harvest of the saphenous vein using the "Mini Harvest System". This device is composed of a blade coupled to a light source. Through a small cutaneous incision, the blade is placed under the skin and allows progressive dissection of the vein under direct vision. We compare this technique ("minimal invasive" group, n = 48) to the conventional method in which extensive incisions are performed along the saphenous vein course ("standard", n = 54). Both groups are comparable in term of age, sex, diabetes, peripheral arterial disease or obesity. The number of bypass performed is also comparable in the two groups. The ratio of the mean length of the cutaneous incision and the mean length of the vein was 35.4 +/- 5.9% for the "minimal invasive" group and 104.5 +/- 23.3% for the "standard" group (p < 0.001). The local complication rate is significantly reduced with a reduction in local post-operative pain (2% vs. 17%, p = 0.01), a better healing (100% vs. 79%, p = 0.01), a reduction in hematoma (31% vs. 52%, p = 0.03) and in oedema (37% vs. 59%, p = 0.03). We conclude that besides the evident aesthetic benefit, minimally invasive harvest of the saphenous vein allows for a better cicatrization and reduces the post-operative discomfort without compromising the aorto-coronary bypass procedure.

Aged↗

PubMed1998

["Minimally invasive" surgical closure of the patent foramen ovale].

AIM OF THE STUDY: After the abdomen and the thorax, the cardiac approach seems to be the logical next step in development of minimally invasive surgery. We report our initial experience in closure of patient foramen ovale (PFO) through a mini thoracotomy. METHOD: A cardio-pulmonary bypass is initiated through canulaes introduced into the external iliac artery and vein. A right anterior mini-thoractomy is performed in the fourth intercostal space and a video-endoscopic camera is introduced through a trocar placed more laterally. The pericardium is opened anteriorly to the phrenic nerve. A venous canula is introduced into the superior vena cava and connected to the extracorporeal circuit. A ventricular fibrillation is provoked and both vena cavaes are clamped before the right atrium is opened. The PFO is closed with a double running suture. DISCUSSION: From November 1996 to march 1997, 4 patients were operated that way. The mean operation time was 212 +/- 17 minutes, the mean CPB time was 73 +/- 32 minutes, and the mean fibrillation time was 32 +/- 15 minutes. Echocardiography was performed at the end of the operations and at day 7. No residual shunt was detected and the cardiac function was not changed compared to the preoperative examination. CONCLUSION: Closure of a PFO can be performed through a mini-thoracotomy, with good results. With growing experience, the "minimally invasive" approach shall rapidly become a standard technique for this indication.

Endoscopes↗

PubMed1998

[Hemodynamic effects of maximum laser transmyocardial revascularization].

The aim of this study was to determine the haemodynamic reaction of a heart in which the left lateral wall was bored with laser channels until cardio-vascular collapse. Four calves were selected for the study. Series of five channels were bored with a 1.75 mm diameter laser probe. Each series was followed by a break of three minutes at the end of which haemodynamic parameters were recorded. The evolution of these parameters then underwent linear regression analysis. Calculations were made according to the percentage of the total number of channels, in order to standardize the results between the animals. Respectively 150, 155, 270 and 285 channels were bored. In each case, all haemodynamic parameters dropped abruptly during the last series of channels. Central venous pressure, mean pulmonary artery pressure, wedge pressure, mean arterial pressure and cardiac output followed a linear regression slope which did not significantly differ from zero. Heart rate only increased progressively with a liner regression slope significantly different from zero. In this acute model, haemodynamic parameters, except heart rate, did not correlate to the extent of damage imposed on the left ventricle. Thus, the presence of haemodynamic stability does not exclude important myocardial damage in an acute situation. This can be found in a clinical setting.

Animals↗

PubMed1997

Drawback of aortoplasty for aneurysm of the ascending aorta associated with aortic valve disease.

BACKGROUND: Aortoplasty has been advocated for moderate dilatation of the ascending aorta associated with aortic valve disease. We report our results with this conservative approach. METHODS: Seventeen consecutive patients with unsupported aortoplasty were reviewed. Twelve patients had aortic valve regurgitation and 5 had stenosis. The aortic wall was analyzed histologically in 14 patients. Follow-up was complete, with a mean time of 6 years (range, 2.3 to 10.5 years). RESULTS: Two patients among the 15 hospital survivors died during follow-up of causes unrelated to aortic pathology. Survival at 7 years was 86.7% (+/- 8.8%). Recurring aortic aneurysms developed in 4 patients after a mean time of 63 months, with an event-free survival at 7 years of 41% (+/- 21%). All of these 4 patients had aortic valve regurgitation and cystic medial necrosis. CONCLUSIONS: The recurrence rate of aneurysms after unsupported aortoplasty and aortic valve replacement is high in patients with aortic regurgitation. This strongly suggests that in these patients, the aortic dilatation is related to an underlying wall deficiency, associated with the aortic valve pathology, rather than to the hemodynamic stress imposed by the aortic valve disease.

Actuarial Analysis↗

PubMed1997

Minimally invasive harvest of the saphenous vein for coronary artery bypass grafting.

BACKGROUND: Preparation of the great saphenous vein for coronary artery bypass grafts is traditionally performed through one or many long cutaneous incisions. We describe the dissection of the great saphenous vein through small cutaneous incisions using the Mini Harvest System. METHODS: The device is composed of a retractor coupled to a light source. Introduced under the skin, above the anterior plane of the vein, it allows an easy preparation of the vein under direct vision. The entire vein can be dissected from the ankle to the groin through sequential cutaneous incisions along the leg. A prospective, randomized trial was performed to compare the minimally invasive vein harvest technique (group 1, n = 15) versus the standard method (group 2, n = 15). RESULTS: In addition to an internal mammary artery graft, 28 venous coronary bypass grafts were performed in group 1 (mean, 1.9 +/- 1.0) and 32 in group 2 (mean, 2.1 +/- 1.0). The mean cutaneous incision length divided by the mean length of the harvested vein was 10.8 cm/32.3 cm = 33% for group 1 and 37.6 cm/33.2 cm = 113% in group 2 (p < 0.001). Wounds were examined daily and a final assessment was performed on day 7. Better cicatrization, less hematoma and edema, and less pain were observed in group 1. CONCLUSIONS: Minimally invasive harvest of the great saphenous vein offers many advantages over the traditional harvest method. Besides the aesthetic aspect, healing is better and postoperative discomfort is reduced.

Coronary Artery Bypass↗

PubMed1997

Long-term results of surgical subxiphoid pericardial drainage.

A series of 64 consecutive patients who underwent surgical subxiphoid drainage of pericardial effusion over an 11-year period, was analysed both for recurrence of pericardial pathology and survival. The mean follow-up time was 4 years (6 months to 10 years). Twelve patients had recurrent effusion (18%), all except one within 6 months: six patients (9%) had another drainage procedure which was the definitive treatment except in one terminal cancer patient with intractable malignant effusion who died of cardiac tamponade. The remaining six recurrent effusions could be treated conservatively. One patient with idiopathic effusion developed late constrictive pericarditis. Patients with underlying malignancy (n = 26) had significantly worse actuarial survival than the others (actuarial survival at 1 and 5 years of 51% and 0% vs 87% and 76%, respectively). However, their probability of remaining free of recurrence did not differ significantly (actuarial freedom at 1 year of 89% vs 76%). In conclusion, subxiphoid drainage provides a simple, safe and expeditious treatment of most symptomatic pericardial effusions with one in ten patients requiring a repeat drainage for recurrence. In particular, it offers a good palliation in most patients with underlying neoplastic disease. Routine echocardiography is recommended at one and six months to catch most of the recurrent effusions.

Actuarial Analysis↗

PubMed1997

Etiologic diagnosis of pericardial disease: the value of routine tests during surgical procedures.

BACKGROUND: The cause of pericardial disease often is unclear. Pericardial surgery provides a unique opportunity to obtain tissue and fluid samples for diagnostic tests. We report our experience with these tests and assess their value in etiologic determination. STUDY DESIGN: The medical records of 92 who underwent 95 operations for pericardial disease were reviewed. The procedures included 75 biopsies and drainages and 20 pericardiectomies. We analyzed the diagnostic yields of routine histology of the removed pericardial specimens, together with culture, cytology, and biochemistry examinations of the fluid drained. RESULTS: A specific etiologic diagnosis was obtained in 20 patients (22 percent): 12 neoplasias, 5 infections (1 bacterial, 4 tuberculoses), 2 chylopericardia, and 1 amyloidosis. Diagnosis was made histologically in 10 (10.5 percent) of 95 examinations, cytologically in 12 (16 percent) of 73 examinations, by culture in 5 (7 percent) of 73 examinations, and by biochemistry in 2 (3 percent) of 73 examinations. Pericardial disease was the first manifestation of an underlying extrapericardial disorder in 11 patients (12 percent), and 8 of these patients had neoplasias and 3 had tuberculoses. Twenty-seven patients (29 percent) had underlying neoplastic disease, and in 15 patients, neither cytology nor histology revealed neoplastic involvement of the pericardium. In 2 of the 15 patients, who died shortly after the operation, pericardial invasion was demonstrated at postmortem examination. CONCLUSIONS: One fifth of the patients had a specific etiologic diagnosis with important implications for prognosis and management, supporting the routine use of diagnostic tests in all pericardial surgical procedures. Negative cytology and histology results do not rule out pericardial invasion in patients with neoplastic disease.

Adolescent↗

PubMed1997

Perioperative morbidity and mortality in combined aortic and mitral valve surgery.

BACKGROUND AND AIMS OF THE STUDY: Despite many significant improvements in cardiac surgical technique, the operative risk for combined aortic and mitral valve surgery remains between 5% and 12%. Identification of high-risk patients will allow surgeons to develop strategies to improve these results. METHODS: The 30-day postoperative mortality and complication rates were analyzed in a group of 206 patients operated on over a 16-year period with cold crystalloid cardioplegia. Thirty-three possible risk factors for death and low output syndrome (LOS) were entered into univariate and multivariate logistic regression analysis. RESULTS: There were 10 perioperative deaths (4.9%). Major complications occurred in 38 patients (18.4%), 19 with LOS. On univariate analysis, right atrial pressure (RAP) > or = 8 mmHg (p = 0.001), aortic stenosis (p = 0.009) and systolic pulmonary artery pressure > or = 60 mmHg (p = 0.095) were found to be risk factors for death, as were RAP > or = 8 mmHg (p = 0.001), previous heart surgery (p = 0.007), serum creatinine > or = 120 mumol/l (p = 0.03), tricuspid valve disease (p = 0.038) and aortic stenosis (p = 0.09) for LOS. On multivariate analysis, RAP > or = 8 mmHg (p < 0.001) and aortic stenosis (p = 0.002) were identified as independent risk factors for death, as were RAP > or = 8 mmHg (p = 0.001) and previous heart surgery (p = 0.008) for LOS. CONCLUSIONS: Mitro-aortic valve surgery involves complex procedures with substantial mortality and morbidity. The risk factors point toward the importance of operating before the stage of advanced heart failure and toward the key role of better myocardial protection techniques in these compromised hearts with limited reserves.

Adolescent↗

PubMed1992

[Blood pressure measurement during tachyarhythmia: validation of a graduated measuring technique with an intra-arterial technique].

Use of the usual technique to measure blood pressure is known to be unsatisfactory in tachyarrhythmia. An easy and non-invasive technique, called the stage by stage method, has therefore been proposed. The aim of the present study is to verify the precision of this method by comparison with intraarterial measurements. The study was performed in 9 tachyarrhythmic patients with heart rate over 90/min and wide systolic pulse amplitude variations. For systolic pressure, the results show an excellent correlation between the blood pressure values obtained by the stage by stage method and those obtained by intraarterial measurements (r = 0.99; p > 0.01). For diastolic pressure, the best practical approximation is the value of the last stage before all sounds have disappeared plus 5 mm Hg. We conclude that the bedside stage by method is worth performing in patients presenting with tachyarrhythmia and wide systolic pressure variations from one systole to the other.

Aged↗

PubMedDate not supplied

In situ control of cardiotomy suction reduces blood trauma.

Cardiotomy suction is known for its deleterious effects on formed and unformed blood elements. The authors investigated an "intelligent" remote controlled automatic suction system. A suction cannula with an optic sensor at its tip was connected to a special closed cardiotomy reservoir. Contact with blood immediately generated a reservoir vacuum from 0 to -100 mmHg, permitting aspiration until the blood was no longer detected (automatic shut off). Blood trauma was evaluated in a bovine model, comparing the automatic suction system vs standard continuous aspiration (control) adjusted to -100 mmHg. After full systemic heparinization, five calves (weight, 62.5 +/- 4.4 kg) for the automatic suction system group, and four (weight, 62.8 +/- 5.1 kg) for the control group, were equipped with a jugular cannula connected via a roller pump to the cardiotomy reservoir. Through a small thoracotomy, a standardized hole was created in the right atrium, allowing for a blood loss of approximately 400 ml/min. The suction cannula was placed into the chest cavity in a fixed position. Blood samples were drawn at regular intervals for cell count and chemistry. Lactate dehydrogenase values, for the automatic suction system and the control groups, respectively, expressed as percent of baseline value, were 88 +/- 14 vs 116 +/- 22 after 1 hr; 94 +/- 16 vs 123 +/- 23 after 2 hr; and 97 +/- 19 vs 140 +/- 48 after 3 hr (p < 0.05). Values for free hemoglobin in plasma (percent of baseline value), for the automatic suction system and the control groups, respectively, were 102 +/- 18 vs 200 +/- 69 after 1 hr; 98 +/- 29 vs 163 +/- 37 after 2 hr; and 94 +/- 37 vs 179 +/- 42 after 3 hr (p < 0.05). Compared with a standard continuous aspiration system, in situ regulation of suction significantly reduces blood trauma.

Animals↗

PubMedDate not supplied

Morphometric analysis of heparin coated versus standard intra-aortic balloons.

The adverse effects of systemic heparin administration has led to the development of heparin coated devices. Intra-aortic balloons are frequently used in clinical settings in which complications of systemic heparin, especially bleeding, are feared. The current study evaluated the thromboresistance of heparin coated intra-aortic balloons. Six bovine calves were chosen for the experiment. In each animal, three intra-aortic balloons were inserted, and set to the automatic mode: two in the vena cava for 15 min and 45 min, respectively, and one in the aorta for 6 hr. There were nine standard and nine heparin coated intra-aortic balloons. At the end of the procedures, three samples of each intra-aortic balloon were analyzed with scanning electron microscopy for computed analysis of the balloon surface covered with fibrin and cells. The scanning electron microscopy analysis showed no deposit at any time interval on the heparin coated sample surfaces, whereas 3.6% +/- 9.2% (mean +/- SD) of the standard sample surfaces were covered with deposits at 15 min (p = 0.06), 14.8% +/- 24.3% at 45 min (p = 0.01), and 4.4% +/- 12.4% at 6 hr (p = 0.06). Strikingly, none of the 27 heparin coated samples showed any microscopic deposits, whereas 11 of the 27 standard samples did (p < 0.002). Heparin coated intra-aortic balloons appear to be a promising strategy, especially for patients with absolute or relative contraindications to systemic heparinization.

Animals↗

PubMedDate not supplied

A siliconized hollow fiber membrane oxygenator.

Most membrane oxygenators are built with microporous fibers known for plasma leakage in long-term use such as extracorporeal life support or extracorporeal membrane oxygenation. The current study was designed to evaluate the Quadrox oxygenator in which the fibers have been coated with silicone (Jostra). Six calves (mean weight, 62 +/- 4 kg) were connected to cardiopulmonary bypass (CPB) by jugular venous and carotid arterial cannulation, with a mean flow rate of 3 L/min for 6 hours. They were randomly assigned to a standard Quadrox oxygenator (standard group, n = 3) or a siliconized Quadrox oxygenator (silicone group, n = 3). After 7 days, the animals were sacrificed. A standard battery of blood samples was taken before bypass, after mixing for 10 minutes, and after 1, 2, 5, and 6 hours of perfusion. Analysis of variance was used for repeated measurements. Total oxygen transfer and carbon dioxide transfer did not differ between groups (p = 0.5 for comparison). Blood trauma, evaluated by plasma hemoglobin (Hb), did not detect any significant hemolysis in either group. Thrombocyte and white blood cell count profiles in both groups were parallel and without significant differences (p = 0.1 and 0.6, respectively). At the end of testing no clot deposition was found in the oxygenator. At postmortem, there were no signs of peripheral emboli. The results of this study suggest that this silicone coating of hollow fibers allows for good gas transfer, while preserving all the mechanical advantages of a conventional hollow fiber oxygenator.

Animals↗

PubMedDate not supplied

Hemoglobin substitute and cardiopulmonary bypass.

The effects of diaspirin crosslinked hemoglobin (DCLHb, Baxter Health Care Corp., Round Lake, IL) on oxygen exchange in the setting of cardiopulmonary bypass (CPB) are unknown. Six calves (71.2 +/- 1.3 kg) were connected to CPB by jugular venous and carotid arterial cannulation for 5 hours. Each 1 hour period included 45 min of partial CPB (mean flow rate of 50 ml/kg per min) followed by 15 min without CPB, at the end of which 500 ml of blood were substituted for with either 500 ml of hydroxyethyl starch (Haes; n = 3) or 500 ml of DCLHb (n = 3). A total of 2 liters of blood was, thus, exchanged (28 ml/kg of blood substitute). Values are expressed as mean +/- 1 SD. Analysis of variance for repeated measurements was used. The cardiac output (CO) values at 1 h, 3 h, and 5 h were in the Haes group: 5.7 +/- 2, 6.7 +/- 2.5, and 7.7 +/- 2.5L/min, and in the DCLHb group: 5.7 +/- 0.6, 4 +/- 1, and 4.7 +/- 1.2 L/min, respectively. The arteriovenous oxygen content difference (Ca-Cvo2) values at 1 h, 3 h, and 5 h were in the Haes group: 4.6 +/- 1, 3.3 +/- 1.5, and 3.5 +/- 1.5 ml/dl, and in the DCLHb group: 4.9 +/- 0.6, 7.4 +/- 0.7, and 6.6 +/- 0.6 ml/dl, respectively. The oxygen consumption (Vo2) values at 1 h, 3 h, and 5 h were in the Haes group: 244 +/- 29, 198 +/- 58, and 249 +/- 42 ml/min, and in the DCLHb group: 273 +/- 28, 296 +/- 75, and 306 +/- 65 ml/min, respectively. CO and Ca-Cvo2 showed a significant difference (p < 0.01), whereas Vo2 did not (p = 0.52). In the DCLHb group of this CPB animal model, the cardiac output is lower and the arteriovenous oxygen content difference higher than in the Haes group, allowing for preserved oxygen consumption.

Animals↗

PubMedDate not supplied

Nitric oxide added to the sweep gas infusion reduces local clotting formation in adult blood oxygenators.

Nitric oxide (NO) is an inhibitor of platelet aggregation. We analyzed the effect of direct infusion of NO into adult blood oxygenators on local clot formation. Nonheparinized calves in a control group (n = 3) and NO group (n = 4) were connected to a jugulocarotid cardiopulmonary bypass (CPB; centrifugal pump) for 6 hours. The venous line and pumphead were heparin coated, whereas the oxygenator, the heat exchanger, and the arterial line were not. A total of 80 ppm of NO was mixed with the sweep gas infusion in the NO group. The pressure gradient through the oxygenator (delta P.Ox.) was monitored, and its evolution was compared between groups. Oxygenators membranes were analyzed and photographed, allowing for calculation of the percentage of surface area covered with clots by using a computer image analysis program. The delta P.Ox. reached a plateau of 193 +/- 26% of the basal value in the NO group after 120 minutes, whereas a similar plateau of 202 +/- 22% was reached after only 20 minutes in the control group (p < 0.05). The surface area of the oxygenator covered with clots was significantly reduced in the NO group (0.54 +/- 0.41%) compared with the control group (5.78 +/- 3.80%, p < 0.05). However, general coagulation parameters were not modified by local NO administration. The activated coagulation time remained stable between 110 and 150 seconds in both groups (p = not significant [ns]), and there were no differences in hematocrit, thrombin time, partial thromboplastin time, or fibrinogen between groups during the 6 hours of CPB. Thus, the mixed infusion of a continuous low dose of NO into adult oxygenators during prolonged CPB prevented local clot formation, whereas the general coagulation pattern remained unchanged.

Animals↗

PubMedDate not supplied

Atrial, ventricular, or both cannulation sites to optimize left ventricular assistance?

The efficiency of left ventricular assist devices (LVADs) depends on the capacity of the inflow cannula to drain blood into the pump. Left atrial (LA) and left ventricular (LV) sites were compared in an animal model mimicking different hemodynamic conditions. Three calves (56.3+/-5.0 kg) were equipped with a Thoratec LVAD. A regular cardiopulmonary bypass (CPB) circuit was used as a right ventricular assist device (RVAD) (jugular vein/pulmonary artery), and preload conditions were adjusted by storage (or perfusion) of blood into (or from) the venous reservoir. LA and LV drainage, tested separately or simultaneously, was measured by its effect on the LVAD's performance. The LVAD was used alone on a beating heart or together with the RVAD (biVAD) on a beating and on a fibrillating heart. Increasing the central venous pressure (CVP) highlighted the differences between the LA and LV cannulation sites when the LVAD was tested either alone or together with the RVAD (biVAD) on a beating heart. Drainage through the LA or the LV was similar when CVP was set at 8 mm Hg, and increasing CVP to 14 mm Hg allowed for better drainage through the LV cannula. In contrast, after induction of fibrillation to mimic extreme heart failure, the drainage was better through the LA cannula. Using both LA and LV cannulae simultaneously did not improve the LVAD output in any of the conditions tested. LV cannulation provides better blood drainage when used on a normal beating heart and, therefore, allows for increased LVAD performance. However, in severe heart failure, blood drainage through the LV cannula decreases and the LA cannulation site is superior.

Animals↗

PubMedDate not supplied

Vacuum assisted venous drainage does not increase trauma to blood cells.

Although gravity drainage has been the standard technique for cardiopulmonary bypass (CPB), the development of min imally invasive techniques for cardiac surgery has renewed interest in using vacuum assisted venous drainage (VAVD) Dideco (Mirandola, Italy) has modified the D903 Avant oxygenator to apply a vacuum to its venous reservoir. The impact of VAVD on blood damage with this device is analyzed. Six calves (mean body weight, 71.3 +/- 4.1 kg) were con nected to CPB by jugular venous and carotid arterial cannu lation, with a flow rate of 4-4.51 L/min for 6 h. They were assigned to gravity drainage (standard D903 Avant oxygen ator, n = 3) or VAVD (modified D903 Avant oxygenator, n = 3). The animals were allowed to survive for 7 days. A standard battery of blood samples was taken before bypass, throughout bypass, and 24 h, 48 h, and 7 days after bypass. Analysis of variance was used for repeated measurements. Thrombocyte and white blood cell counts, corrected by hematocrit and normalized by prebypass values, were not significantly different between groups throughout all study periods. The same holds true for hemolytic parameters (lactate dehydrogenase [LDH] and plasma hemoglobin). Both peaked at 24 hr in the standard and VAVD groups: LDH, 2,845 +/- 974 IU/L vs. 2,537 +/- 476 IU/L (p = 0.65), respectively; and plasma hemoglobin, 115 +/- 31 mg/L vs. 89 +/- 455 mg/L (p = 0.45), respectively. In this experimental setup with prolonged perfusion time, VAVD does not increase trauma to blood cells in comparison with standard gravity drainage.

Animals↗

PubMedDate not supplied

Is an endocardial connection necessary for growth factor induced angiogenesis in transmyocardial laser revascularization?

Transmyocardial laser revascularization (TMLR) and therapeutic angiogenesis had emerged as potential tools in the treatment of angina refractory to conventional therapies. This combination might potentiate their effects, because angiogenesis is believed to be a basic mechanism in TMLR. The influence of channel connection with endocardial blood flow on angiogenesis is unclear. Twenty-five pigs (mean weight, 72.3 +/- 5 kg) were randomly assigned into five groups. In the transmural laser group, five transmyocardial channels were drilled. In the transmural mixed group, the same protocol was used followed by the injection of 100 microg of bovine bone derived growth factor mixture within each channel. The nontransmural laser group and the nontransmural mixed group underwent the same procedures, respectively, but the laser channels were drilled through the outer two-thirds of the myocardial wall. The control group had sham operations. Animals were allowed to survive for 1 month. Vascular densities were determined by computed morphometric analysis of histologic sections. Vascular counts of areas adjacent to the channels in the non- and transmural laser groups did not differ significantly from control groups (arteriolar counts: 0.27 +/- 0.16 and 0.26 +/- 0.16 vs. 0.29 +/- 0.11/mm2, respectively). When bovine bone protein growth factor mixture is added, neovascularization is increased significantly in non- and transmural mixed groups (1.04 +/- 0.79 and 0.69 +/- 0.37/mm2, respectively, p < 0.001 for both comparisons with corresponding laser groups), and there was no significant difference between mixed groups (p = 0.13). In this porcine model, the combination of TMLR with injection of bone protein growth factor mixture induced angiogenesis around the laser channels. Whether the channels did or did not communicate with the endocardial cavity did not influence the neovascular density.

Animals↗