Impact of bispectral index monitoring on postoperative delirium in patients undergoing aortic surgery.

BACKGROUND: Bispectral index monitoring can facilitate anesthesia care. We evaluated the association of Bispectral index with postoperative neurological outcome and delirium in patients undergoing aortic surgery. METHODS: From 2006 to 2009, 292 consecutive patients undergoing aortic surgery were retrospectively reviewed. Patients were classified into 5 groups according to Bispectral index reduction: Group I (≤15%), Group II (15-20%), Group III (20-25%), Group IV (25-30%), and Group V (>30%). RESULTS: The number of patients in each group was : 52 (17.8%), Group I; 125 (42.8%), Group II;68 (23.3%), Group III; 33 (11.3%), Group IV; 14 (4.8%), Group V. The incidence of delirium and neurological events was higher in Group IV and Group V(90.9% and 18.2% in Group IV, and 71% and 79% in Group V; both p<0.001). Only Group V showed a longer intensive care unit stay compared to Group I (13.5±10.3 vs 5.4±6.6 days; p=0.002), Group II (7.3±8.6 days, p=0.005) and Group III (6.7±6.5 days, p=0.015). Group V also showed a longer intubation time compared to Group I (228±211 vs 73±112 hours; p=0.008) and Group II (105±177 hours, p=0.002). CONCLUSIONS: Our data suggest a higher incidence of neurological deficits in patients with a Bispectral index reduction of >25% from baseline. Explanations for these findings are speculative with regard to the underlying mechanisms, and larger studies are warranted to clarify these issues.

Triangular resection of the anterior leaflet for repair of the mitral valve.

Isolated anterior mitral leaflet prolapse, unlike posterior prolapse, is a difficult lesion to repair and may become a demanding surgical procedure. We report our experience with a technique of a triangular resection of the anterior leaflet to repair isolated segmental anterior leaflet prolapse in 18 patients. This technique simplifies the repair procedure and is a safe and rapid procedure which allows excellent results.

Papillary muscle repair surgery in ischemic mitral valve patients.

BACKGROUND: Ischemic mitral regurgitation (MR), when ischemia/infarction has resulted in fibrotic degeneration and elongation of papillary muscles, carries a high risk for the patient and a technical challenge for the surgeon. We have developed a papillary-shortening plasty for this specific pathology. METHODS: Papillary muscle repair was performed in 88 patients (7.2%) where degenerated and fibrotic elongated papillary muscles were found, which resulted in a prolapse of one or more parts of the mitral valve leaflets (MR III-IV). All patients had a papillary muscle-shortening plasty using a pericardium pledged-reinforced polytetrafluoroethylene suture and a ring annuloplasty. Because the cause of regurgitation in this specific group of patients was ischemic, concomitant coronary bypass grafting was required in all patients, with 2.2 grafts/patient. RESULTS: There were five hospital deaths (5.7%). Postoperative mitral valve function was satisfactory in all patients: no residual mitral regurgitation (MR 0) was found in 80 patients (90.9%), mild regurgitation (MR I) in 5 patients (5.7%), and moderate regurgitation (MR I-II) was observed in 3 patients (3.4%). Within a short mean follow-up period of 18.6 months (3 to 40 months), there was one late death (1.2%). The actuarial freedom from reoperation and thromboembolic complications was 100%, but there were two anticoagulation-induced gastric bleeding complications (2.3%). All patients were in New York Heart Association functional class I or II at the time of follow-up. CONCLUSIONS: Our data show that careful assessment of papillary muscle pathology is mandatory, and that a papillary muscle-shortening plasty is a simple but valuable surgical tool to repair the mitral valve in this specific group of high-risk patients with ischemic mitral regurgitation.

Early failure of bioprosthesis by preserved mitral leaflets.

Complete preservation of the posterior mitral valve leaflet caused early thrombotic occlusion of two cusps of a Carpentier-Edward pericardial prosthesis implanted into the mitral position with subsequent bioprosthetic failure, necessitating reoperation.

Mitral repair in patients with a ruptured papillary muscle.

BACKGROUND: The objective of this study was to evaluate the feasibility of a modified papillary muscle repair procedure for a group of patients with ischemic mitral regurgitation when ischemia/infarction has resulted in the rupture of a papillary muscle. From January 1997 to January 1999, 843 patients underwent mitral valve surgery in our hospital. Mitral reconstruction was performed in 520 (61.7%) patients, and 6 (1.2%) of these patients were found to have a rupture of a papillary muscle at initial examination. METHODS AND RESULTS: A modified papillary muscle repair procedure to reimplant the tip of the ruptured papillary muscle "height- and/or length-adjusted" into a corresponding papillary muscle, with the use of a sandwiched pericardium pledget-reinforced polytetrafluoroethylene suture, was performed in 6 patients. Although the underlying cause in this group of patients was ischemic, concomitant coronary artery bypass grafting was performed in only 3 patients, with 1.3 grafts per patient. Of these 6 patients, 3 (50%) were men; the mean age was 60.2 +/- 12.8 years. All patients had in addition to the papillary muscle repair procedure an annuloplasty with a Carpentier-Edwards Physio-Ring. There was no early death in this group of patients. Postoperative Doppler echocardiography showed satisfactory mitral valve function in all patients and a significant postoperative ventricular remodeling: The left ventricular end-diastolic diameter decreased from 72.8 +/- 3.1 mm before surgery to 54.6 +/- 9.3 mm (P <.1) after surgery; left ventricular systolic diameter also decreased (48.5 +/- 4.9 mm vs 38. 4 +/- 9.8 mm; P <.1), and a substantial reduction of left atrial diameter (58.8 +/- 1.5 mm vs 49.7 +/- 4.1 mm; P <.1) was observed. Within the short mean follow-up period of 8.6 +/- 7.5 months (2 to 26 months), there were no late deaths, reoperations, or thromboembolic or bleeding complications. All patients were in New York Heart Association functional class I or II at the time of follow-up. CONCLUSIONS: Our results indicate that our modified papillary muscle reimplantation procedure is a valuable surgical tool with good survival results in patients with ischemic mitral regurgitation caused by papillary muscle rupture.

Papillary muscle shortening for mitral valve reconstruction in patients with ischaemic mitral insufficiency.

AIMS: To evaluate the feasibility of papillary muscle shortening in a specific group of high risk patients with ischaemic mitral regurgitation undergoing mitral valve reconstruction. BACKGROUND: From January 1996 to December 1997, 712 (10.1%) out of a total of 7042 open heart patients underwent mitral valve surgery in our hospital. Mitral valve reconstruction was performed in 408 of these patients (57.3%) and valve replacement had to be performed in 304 patients (42.7%). METHODS: A specific technique of papillary muscle reconstruction was performed in 32 patients undergoing valve reconstruction (7.8%). These cases had degenerated and had developed fibrotic elongated papillary muscles, which resulted in prolapses of one or more parts of the mitral valve leaflets. The aetiology in this group of patients was ischaemic, requiring concomitant myocardial revascularization in 28 patients (87.5%) with a mean of 2.7 grafts/patient. All patients underwent papillary muscle shortening using a pericardium pledget-reinforced Polytetrafluoroethylene suture and annuloplasty with a Carpentier-Edwards Physio Annuloplasty Ring. Of these 32 patients, 17 (53.1%) were male, the mean age was 67.1+/-9.7 years (range 41 to 81 years) and all but one were in pre-operative NYHA class III or IV. RESULTS: There were two hospital deaths (6.2%). Postoperative Doppler echocardiography indicated satisfactory mitral valve function in all patients. Within the short mean follow-up period of 9.6+/-5.4 months (3 to 26 months) there was one non-cardiac-related death (3.1%). There was no need for reoperation, and no cases of thromboembolic and bleeding complications in the postoperative period. All patients were in NYHA functional class I or II at the time of follow-up. CONCLUSION: Our results indicate that mitral valve repair is a safe treatment for this group of high risk patients, and that papillary muscle shortening is a valuable tool in these patients with ischaemic mitral regurgitation undergoing surgery.

In vitro endothelialization of bioprosthetic heart valves.

BACKGROUND AND AIMS OF THE STUDY: The main disadvantage of xenograft bioprosthetic heart valves is limited durability due to tissue degeneration. METHODS: To study possible alternatives to conventional bioprosthetic heart valves, glutaraldehyde preserved porcine aortic valve leaflets were precoated with fibronectin-heparin and acidic fibroblast growth factor (aFGF) to enhance cell proliferation. Furthermore, different methods of storage and preservation (1.0% benzoic acid, 1.0% sorbic acid, 0.05% and 0.5% dialdehyde starch) were compared to conventional preservation procedures. Valve leaflets were lined with adult human saphenous vein endothelial cells (1.0 x 10(4) AHSVEC/cm2). The different methods of preservation were compared to leaflets precoated additionally with 1.0 microgram/cm2 aFGF protein, derived from gene manipulated bacteria. Endothelial growth kinetics were studied and verified by an increase of activation following 3H-thymidine incorporation, while the maintained metabolic cell activity was demonstrated by prostacyclin (PGI2) release measurements. In subsequent experiments in vivo degeneration and mineralization were determined by subcutaneous implantation in rats for up to 40 days. RESULTS: Our results favored alternatively treated valve leaflets; endothelial cells grew to persistent monolayers in six to 12 days in contrast to conventional processed leaflets where no endothelial cell growth was possible. Atomic absorption spectroscopic assessment of subdermal valve implants showed significantly lower contents of calcium, magnesium and phosphate in alternatively treated leaflets. Furthermore, precoating of alternatively preserved valve leaflets with aFGF protein and endothelial cells improved in vitro and in vivo results significantly. CONCLUSIONS: Our study shows that endothelial cell growth as well as significantly reduced in vivo degeneration and mineralization of valve leaflets may be feasible if bioprosthetic heart valves are processed according to alternative, non-toxic conservation procedures and are precoated with angiogenic growth factor protein.

Effect of peri-operative diltiazem on myocardial ischaemia and function in patients receiving mammary artery grafts.

A prospective, randomized study was performed with 66 patients undergoing elective coronary bypass surgery involving internal mammary artery (IMA) grafts to the left anterior descending artery (LAD). Patients received a continuous peri-operative infusion of either diltiazem (0.1 mg.kg-1 h-1, n = 32) or nitroglycerin (1 microgram.kg-1 min-1, n = 34) for 24 h. The aim of this study was to define the effect of the calcium channel blocker diltiazem on peri-operative ischaemia, arrhythmias and myocardial function in patients receiving arterial bypass grafts by preventing transient vasospasm. The study patients did not differ with respect to pre-operative, operative and haemodynamic data. Patients treated with diltiazem had lower numbers of ventricular premature beats/hour (8.1 +/- 7.8 vs 20.5 +/- 11.2; P < 0.05). The anti-ischaemic efficacy of peri-operative diltiazem in patients receiving IMA grafts significantly reduced the incidence and duration of transient ischaemic events (0 vs 5). Additionally, patients receiving IMA grafts and diltiazem showed significantly lower peak levels of ischaemia-sensitive laboratory parameters, as compared to IMA graft patients receiving only nitroglycerin: CK-MB: 17.3 +/- 7.7 vs 23.5 +/- 11.0, (P < 0.05); MB-M: 29.4 +/- 14.7 vs 43.1 +/- 27.4, (P < 0.05); troponin-T: 0.88 +/- 0.6 vs 1.41 +/- 0.9, (P < 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Functional significance of angiotensin receptors in human myocardium. Significant differences between atrial and ventricular myocardium.

We studied the effects of angiotensin (Ang) I and II in a variety of isolated human cardiac tissues contracting under physiological conditions (37 degrees C, 60 beats.min-1). Ang I and II consistently increased the peak developed force of human atrial muscles by 30-40%, an effect that was completely blocked by 10(-6) M saralasine, but not by the combination of prazosin and propranolol. However, neither Ang I or II had significant inotropic effects in right and left ventricular human preparations. We were also able to demonstrate that the positive inotropic effect of Ang II in human right atrial tissue is mediated by the AT1 receptor subtype but not the AT2 receptor subtype.

In vitro-lined endothelium: initial integrity and ultrastructural events.

BACKGROUND: The early fate of in vitro-endothelialized prosthetic vascular grafts was assessed in the nonhuman primate. METHODS: Each of 17 male chacma baboons received a control and a confluently endothelialized 4 mm polytetrafluoroethylene graft in femoro-femoral positions (8.2 +/- 0.8 cm). All experimental grafts were precoated with fibrinolytically inhibited fibrin glue and lined with cultured autologous endothelial cells (EC) from the external jugular vein. The average time period needed to obtain first-passage mass-cultures sufficient for preconfluent graft endothelialization was 19.8 +/- 5.2 days. Before implantation in vitro-lined grafts were kept in culture for another 16.1 +/- 4.3 days to achieve complete confluence and maturation of the EC cytoskeleton. RESULTS: After 9 days of implantation, endothelial-lined grafts still showed a confluent endothelium that was free of any fibrin deposits. However, the EC density was significantly lower than at implantation (39.7 +/- 7.6 x 10(3) versus 59.9 +/- 8.5 x 10(3) EC/cm2; p < 0.05), and occasional 10-microns-wide intercellular gaps with adherent platelets and leukocytes were visible. Transmission electron microscopy showed leukocytes and cell debris in the underlying fibrin glue. After 4 weeks of implantation, the endothelium of experimental prostheses had regained a high cell density (72.7 +/- 10.5 x 10(3) EC/cm2) with a mature and well-differentiated morphologic appearance. At both observation periods, the surface of control grafts showed a wide range from fibrin deposits to an amorphous protein coverage containing spread platelets. CONCLUSIONS: The endothelium of in vitro-endothelialized vascular prostheses remains confluent after implantation and is nonthrombogenic in spite of a moderate initial cell loss.

Experimental use of a modified fibrin glue to induce site-directed angiogenesis from the aorta to the heart.

From 10 cultures of manipulated Escherichia coli bacteria expressing the class I heparin-binding growth factor polypeptide alpha-endothelial cell growth factor, 11.2 +/- 0.7 mg alpha-endothelial cell growth factor was eluted by heparin-sepharose affinity chromatography. Analysis of molecular weight (17,000 kD) was done by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and purification of the growth factor was done by high-performance liquid chromatography. The harvested alpha-endothelial cell growth factor was proved by protein blotting. To assess the growth-promoting activity, we did an endothelial cell growth assay by comparing adult human endothelial cell control cultures, without adding growth factor to the culture medium, with adult human endothelial cell cultures with 0.02 to 20.0 ng/ml alpha-endothelial cell growth factor and 1.0 ng/ml heparin and with adult human endothelial cell cultures with alpha-endothelial cell growth factor but without heparin. Tritiated thymidine counts proved the significant growth-promoting activity of alpha-endothelial cell growth factor. In 10 experimental animals modified fibrin glue containing 1 microgram alpha-endothelial cell growth factor was implanted between the aorta and the myocardium of the left ventricle and results were compared with those in five control animals that received normal fibrin glue without growth factor. After 9 weeks of implantation, angiography and histologic investigation showed newly grown vascular structures between the aorta and the myocardium in all experimental animals, but none in the control animals. Our study proved the feasibility of initiating site-directed formation of new blood vessel structures to the heart by a modified fibrin glue implant containing angiogenic growth factor alpha-endothelial cell growth factor.

Shed blood autotransfusion influences ischemia-sensitive laboratory parameters after coronary operations.

The diagnostic significance of ischemia-sensitive laboratory parameters in respect to possible interference with shed blood autotransfusion was assessed in a prospective study with 100 patients undergoing elective coronary artery bypass grafting. Serum levels of creatine kinase, creatine kinase MB activity, creatine kinase MB mass concentration, 2-hydroxybutyrate dehydrogenase, lactate dehydrogenase-1, troponin-T, myoglobin, and glutamicoxaloacetic transaminase were repeatedly assessed up to the sixth postoperative day. Thirty-seven patients were excluded from the study due to postoperative development of myocardial infarction (n = 4), transient ischemic events (n = 25), and left bundle-branch blocks (n = 8). In the remaining group of 63, 37 patients were retransfused with 580 +/- 370 mL shed blood up to the twelfth postoperative hour, and 26 patients did not receive autotransfusion due to minimal mediastinal blood loss. The results of our study show that the ischemia-sensitive laboratory parameters were significantly influenced by shed blood autotransfusion: 8 hours postoperatively, creatine kinase (272%), creatine kinase MB fraction (151%), 2-hydroxybutyrate dehydrogenase (130%), lactate dehydrogenase-1 (133%), troponin-T (200%), myoglobin (159%) and glutamic-oxaloacetic transaminase levels (153%) were significantly elevated (p < 0.05) in patients with postoperative autotransfusion, although there were no electrocardiographic signs of myocardial ischemia in this group of patients. Our study shows that postoperative autotransfusion of mediastinal shed blood may interfere with the diagnosis of perioperative myocardial ischemia by laboratory parameters in coronary bypass patients.

Effects of diltiazem on perioperative ischemia, arrhythmias, and myocardial function in patients undergoing elective coronary bypass grafting.

A prospective, randomized study was performed on 120 patients undergoing elective coronary bypass grafting to define the effect of the calcium channel blocker diltiazem on perioperative ischemia, arrhythmias, and myocardial function. Patients received a continuous 24-hour perioperative infusion of either diltiazem (0.1 mg/kg per hour, n = 60) or nitroglycerin (1 micrograms/kg per minute, n = 60). Perioperative monitoring included hemodynamic measurements, three-channel Holter monitoring, repeated assessment of 12-lead electrocardiograms, and analysis of ischemia-specific laboratory parameters (creatine kinase, creatine kinase-MB, and creatine kinase-MB-mass and troponin-T). Global and regional systolic function and diastolic compliance were assessed by means of transesophageal echocardiography. The two groups did not differ with respect to preoperative and operative data. Except for a significant reduction in perioperative heart rate, diltiazem had no influence on hemodynamic parameters. The number (17 +/- 9 versus 25 +/- 5, p < 0.05) and the duration (69 +/- 47 versus 104 +/- 87 minutes, p < 0.05) of transient ischemic events were significantly reduced as compared with the nitroglycerin group. In addition, peak values of all assessed laboratory parameters except creatine kinase were significantly lower in the diltiazem group. Patients treated with diltiazem had a lower incidence of perioperative atrial fibrillation (5% versus 18%, p < 0.05) and lower numbers of ventricular premature beats per hour (10 +/- 8 versus 19 +/- 22, p < 0.05) and ventricular runs per hour (5 +/- 17 versus 32 +/- 38, p < 0.05). Postoperatively, the percent fractional area of contraction and percent systolic wall thickening of the anterior wall were significantly improved in the diltiazem group but not in the nitroglycerin group. In addition, the postoperative diastolic flow/velocity ratio was significantly lower in the nitroglycerin group than in the diltiazem group (0.949 +/- 0.391 versus 1.331 +/- 0.475, p < 0.001). It is concluded that perioperative infusion of the calcium antagonist diltiazem has no adverse effect on perioperative hemodynamics and systolic myocardial function and provides potent anti-ischemic and antiarrhythmic protection in patients undergoing coronary bypass grafting.

Angiotensin I and II exert inotropic effects in atrial but not in ventricular human myocardium. An in vitro study under physiological experimental conditions.

BACKGROUND: The renin-angiotensin system with its renal-humoral and local myocardial components plays an important role in the development and progression of chronic heart failure. Whereas angiotensin receptors have been found in atrial and ventricular myocardium of different species including humans, its influence on myocardial contractility is not yet defined in human failing myocardium and especially in human nonfailing myocardium. METHODS AND RESULTS: We measured force development of right atrial and right and left ventricular myocardial preparations of patients with a variety of cardiac diseases. To evaluate the physiological effects of angiotensin, experimental temperature and stimulation rates were 37 degrees C and 60 beats per minute, respectively. Angiotensin I and II increased peak developed force in atrial myocardial preparations obtained from patients without heart failure in a concentration-dependent manner. At optimal concentrations, peak developed force is increased from 10.2 +/- 1.8 to 12.3 +/- 1.9 mN/mm2 by angiotensin I (P < .05) and from 15.4 +/- 2.1 to 20.5 +/- 3.3 mN/mm2 by angiotensin II (P < .05). This effect was not influenced by pretreatment with propranolol (10(-6) mol/L) and prazosin (10(-5) mol/L) but was completely blocked by saralasin (10(-6) mol/L). The positive inotropic effect of angiotensin I could be blocked by enalaprilate (10(-5) mol/L). Neither angiotensin I nor angiotensin II had any effect in preparations of the left ventricle from patients with idiopathic dilated cardiomyopathy, mitral valve stenosis, and incompetence or in patients with no significant heart disease. Additionally, no effect could be seen when angiotensin II was applied to right ventricular preparations from infants undergoing reconstructive heart surgery for tetralogy of Fallot. CONCLUSIONS: Angiotensin I and II exert positive inotropic effects via angiotensin receptors in atrial preparations but not in right or left ventricular preparations. Furthermore, the existence of a local myocardial angiotensin converting enzyme with functional importance is shown.

Diltiazem provides anti-ischemic and anti-arrhythmic protection in patients undergoing coronary bypass grafting.

In 91 patients undergoing elective coronary bypass grafting, the anti-ischemic and anti-arrhythmic efficacy of a 24-hour infusion of either the calcium antagonist diltiazem (0.1 mg/kg per h, n = 44) or nitroglycerin (1 micrograms/kg per min, n = 47) were compared. Myocardial ischemia was diagnosed by Holter monitoring and the repeated assessment of 12-lead ECG and serum enzyme levels and defined as a transient ischemic event, transient coronary spasm or myocardial infarction. The two groups did not differ with respect to preoperative and operative data. Postoperatively, the average heart rate and pulse pressure rate were significantly lower in the diltiazem group. The incidence of postoperative atrial fibrillation (4.5 vs 19.1%, P < 0.01), transient coronary spasm (2.3 vs 11.4%, P < 0.05) and myocardial infarction (4.5 vs 8.5%, not significant) and the frequency of ventricular premature couplets/h (12.1 +/- 4.5 vs 18.1 +/- 5.1, P < 0.05) and ventricular runs/h (2.5 +/- 0.8 vs 6.5 +/- 2.8, P < 0.05) were lower in the diltiazem as compared to the nitroglycerin group. In addition, diltiazem-treated patients had significantly lower postoperative peak values of creatine kinase-MB (19.3 +/- 11.6 vs 29.3 +/- 20.6, P < 0.05). In conclusion, perioperative infusion of diltiazem is effective in reducing the incidence and extent of arrhythmias and myocardial ischemia in patients undergoing elective coronary bypass grafting as compared to patients receiving nitroglycerin.

Growth of "new" coronary vascular structures by angiogenetic growth factors.

The efficacy of the human angiogenetic heparin-binding growth factor I (HBGF-I) to initiate site-directed growth of new blood vessels from the aorta into the myocardium was studied. First, manipulated Escherichia coli bacteria, which had received the human mRNA-transcript for HBGF I into their genetic material, were cultivated. The growth factor derived was purified using heparin-Sepharose affinity chromatography. The separation and characterization of biologically active alpha- and beta-chains was carried out using high pressure liquid chromatography (HPLC) of dialyzed and lyophilized samples from the heparin-Sepharose column. One microgram HBGF I (alpha-ECGF) was bound to polytetrafluoroethylene (PTFE) sponges, precoated with collagen type I, and implanted between the aorta and the myocardium of the left ventricle in experimental rats. Twelve growth factor implants in the experimental group were compared to six controls receiving uncoated PTFE sponges for 9 weeks. Digitized computed angiography showed new blood vessels between the aorta and the myocardium in 11 of the 12 experimental animals, and retrograde coronary perfusion by these "new" vascular structures could be seen. Histology showed no specific structures in the control group (without HBGF I). In the experimental group (with HBGF I) individual vessels with highly differentiated endothelial and smooth muscle cell layers were evident. Our experiments proved the feasibility of induced, site-directed angiogenesis. It is possible to initiate in vivo growth of new "coronary" vascular structures between the aorta and the myocardium.

The influence of obesity on perioperative morbidity: retrospective study of 502 aortocoronary bypass operations.

The incidence of perioperative complications after coronary artery surgery was investigated by a retrospective study of all 502 patients undergoing coronary artery bypass graft (CABG) surgery in our Department between January 1st and December 31st of last year (1990). Furthermore, the influence of obesity on the early results of surgery was assessed and the effect of preoperative weight reduction on perioperative complication rates examined. Obese patients had a greater incidence of left-stem coronary artery stenosis (p less than 0.001), hyperlipidaemia (p less than 0.05), hypertension (p less than 0.05), diabetes mellitus (p less than 0.02), and were in general younger at the time of operation (57.9 +/- 8.4 vs. 60.8 +/- 8.5 years). There were no differences in the surgery performed and in operative mortality, but there were some in perioperative morbidity. Obese patients had higher rates of infection (p less than 0.02), sternal dehiscence (p less than 0.02), arrhythmias (p less than 0.02) and myocardial infarction (p less than 0.02). No significant differences were identified in obese patients with or without preoperative weight reduction, although there was a trend of better postoperative recovery and results in patients having undergone preoperative weight reduction. Analysis of our results demonstrated obesity to be an independent risk factor for perioperative complications, hospital morbidity, and length of hospitalization.

Experimental in vitro endothelialization of cardiac valve leaflets.

This study reports our results with vitro endothelialization of fresh nonpreserved homograft valve leaflets compared with mild alternatively preserved valves and valves treated by preservation procedures commonly used for commercially available tissue valves. In vitro lining of biological heart valves with cultured autologous endothelial cells might help prevent the detrimental effects of degeneration on valve durability. To investigate the growth characteristics of endothelial cells on valve bioprostheses, three different methods of storage and preservation were compared. After precoating with fibronectin and seeding of 4.4 x 10(4) endothelial cells/cm2 onto the different leaflet surfaces, primary adherence, growth kinetics, morphology, and maintenance of monolayer integrity were studied over a period of 10 days. On valve leaflet surfaces of group 1 (fresh nonpreserved homograft valve leaflets) and group 2 (mild alternatively preserved valves), endothelial cells grew to persistent monolayers between days 6 and 10. In contrast, endothelial cell proliferation with monolayer growth could not be achieved on the group 3 leaflets (preserved like commercially available biological valve prostheses). In that group, no viable endothelial cells could be found on the valve surfaces 2 days after seeding. These results demonstrate the theoretical feasibility of endothelializing biological heart valve leaflets in vitro if they are not preserved and stored according to commonly used procedures. Provided such an endothelium can withstand the mechanical forces after implantation in vivo, in vitro endothelialization might contribute either to the development of new biological heart valves for modern cardiac surgery or to the improvement of clinical results with homograft valve transplants.

Growth properties of cultured human endothelial cells on differently coated artificial heart materials.

The cultivation of autologous endothelial cells on the blood surface of artificial hearts might prevent their detrimental thromboembolic complications. To investigate the growth characteristics of endothelial cells on theoretically suitable biomaterials, we compared three polyurethanes (Pellethane, Biomer, Enka) and three silicone rubbers (Elastosil, 3145 RTV, Medical Adhesive). All synthetic surfaces were precoated with an extracellular matrix (group 1), fibronectin (group 2), or a glutaraldehyde-preserved cellular matrix (group 3). After the seeding of 2.5 x 10(4)/cm2 human endothelial cells into the various surfaces, primary adherence, growth kinetics, and maintenance of monolayer integrity were studied for 13 days. On the three polyurethanes all precoating procedures resulted in endothelial cell proliferation and the formation of persistent monolayers. In contrast, on silicone rubbers a persistent coverage with a confluent endothelium could be achieved only on the glutaraldehyde-preserved cellular matrix. When endothelial cell growth was quantitatively assessed on all precoating substrates, the glutaraldehyde-preserved cellular matrix proved to be far superior on each of the synthetics (p less than 0.001). These results demonstrate the theoretical feasibility of endothelialization of artificial hearts in vitro. Provided such an endothelium can withstand the mechanical forces within an artificial heart, in vitro endothelialization might contribute to a regained attractiveness of the elective long-term implantation of artificial hearts.