New approach to patency and flow assessment after left internal thoracic artery hypoperfusion syndrome with additional saphenous vein graft to the left anterior descending artery with phase-contrast magnetic resonance angiography.

OBJECTIVE: Perioperative and early postoperative flow reduction of a left internal thoracic artery conduit is a rare complication of myocardial revascularization and may lead to the potentially fatal left internal thoracic artery hypoperfusion syndrome. It has been advocated that an additional vein graft be placed to the distal left anterior descending artery to provide sufficient myocardial perfusion. Some evidence exists, however, that this high-flow vein might lead to competing or even backward flow through the internal thoracic artery. METHODS: In the past 2 years, 21 patients received an additional vein graft to the distal left anterior descending artery for left internal thoracic artery hypoperfusion syndrome. Nineteen of these patients were available for magnetic resonance imaging. Early (< 6 months) and late (> 12 months) postoperative flow measurements, both in the left internal thoracic artery and in the saphenous vein grafts, were performed by means of conventional and a segmented k-space phase-contrast magnetic resonance angiography technique. RESULTS: Early magnetic resonance examinations indicated that all conduits had adapted to the coronary flow type with predominant diastolic perfusion. Patency rate both at the early and at the late study was 100%. No concurrent flow, flow reversal, or steal phenomena were observed. Mean flow rates were 49.2 ml/min for the left internal thoracic artery and 72.6 ml/min for the saphenous vein graft. CONCLUSION: On the basis of the flow data obtained with magnetic resonance angiography, the use of an additional saphenous vein graft as the treatment of choice in left internal thoracic artery hypoperfusion syndrome does not lead to occlusion of the artery. Conduit flow adaptation to the diastolic predominance occurs in the first 6 months after operation.

Effect of soluble complement receptor type 1 on reperfusion edema and neutrophil migration after lung allotransplantation in swine.

OBJECTIVE: Soluble complement receptor type 1 inhibits complement activation by blocking C3 and C5 convertases of the classical and alternative pathways. We evaluated the effect of soluble complement receptor type 1 on lung allograft reperfusion injury. METHODS: Left lung transplantation was performed in 13 weight-matched pigs (25 to 31 kg) after prolonged preservation (20 hours at 1 degree C). One hour after reperfusion the recipient contralateral right lung was excluded to assess graft function only. Complement activity and C3a levels were measured after reperfusion and at the end of the assessment. Extravascular lung water index, intrathoracic blood volume, and cardiac output were assessed during a 5-hour observation period. Gas exchange and hemodynamics were monitored. At the end of the 5-hour assessment period, myeloperoxidase assay and bronchoalveolar lavage were performed to assess neutrophil migration, and C5b-9 (membrane attack complex) deposits in the allograft were detected by immunohistochemistry. Two groups were studied. In group II (n = 6) recipient animals were treated with soluble complement receptor type 1 (15 mg/kg) 15 minutes before reperfusion. Group I (n = 7) served as the control group. RESULTS: Serum complement activity was completely inhibited in group II. In contrast to group I, C5b-9 complexes were not detected in group II allograft tissue samples. C3a was reduced to normal levels in group II (p = 0.00005). Extravascular lung water index was higher in group I animals throughout the assessment period (p = 0.035). No significant difference in allograft myeloperoxidase activity (p = 0.10) and polymorphonuclear leukocyte count of the bronchoalveolar lavage fluid (p = 0.057) was detected. CONCLUSION: Inhibition of the complement system by soluble complement receptor type 1 blocks local complement activation in the allograft and reduces posttransplantation reperfusion edema but does not improve hemodynamic parameters.

Intractable ventricular tachycardia and bridging to heart transplantation with a non-pulsatile flow assist device in a patient with isolated left-ventricular non-compaction.

Intractable ventricular tachycardia was investigated in a 51-year-old man with isolated left ventricular non-compaction during implantation of an automated internal cardioverter-defibrillator. Favorable bridging to cardiac transplantation was achieved with the DeBakey left ventricular assist device (LVAD).

Pelvic inflammatory disease complicated by massive helminthic hyperinfection.

Strongyloidiasis is a potentially life-threatening condition which, when appropriately diagnosed early in its course, is easily eradicated. When severe, it may mimic other disease processes including appendicitis or severe pelvic inflammatory disease. The diagnosis of parasitic infestation should be considered in any individual who has lived in an endemic area and presents with diarrhea regardless of attendant conditions and superimposed disease processes. A minimum workup consisting of stool examination for ova and parasites should be performed on all such individuals. Thiabendazol is the treatment of choice in nonpregnant patients; however, piperazine tartrate has established safety and efficacy in pregnancy and is therefore preferable in the pregnant patient.

Role of myocardial revascularization in postinfarction ventricular septal rupture.

BACKGROUND: Postinfarction ventricular septal rupture requires urgent closure. The role of systematic coronarography and coronary revascularization needs clarification. METHODS: Fifty-four patients who underwent patch closure of postinfarction ventricular septal defect were reviewed. A coronarography had been systematically and myocardial revascularization selectively (when significant coronary artery stenosis existed) performed. RESULTS: No patient died or deteriorated during coronarography. Twenty-six patients showed no coronary artery disease besides the infarct-related artery, and 28 had associated disease. Threatened myocardial territories were revascularized usually with venous grafts (mean number of distal anastomosis, 2.5). Operative mortality was 19% and 32% (p = 0.36) and late mortality 43% and 53% (p = 0.75) in patients without and in patients with associated coronary artery disease, respectively. Survival curve in both group was similar, at least up to 8 years after operation. CONCLUSIONS: Myocardial revascularization controlled the added risk of associated coronary artery disease in the postoperative period and in median term. A coronarography should be performed in all patients who can be stabilized hemodynamically and myocardial revascularization performed in case of significant stenosis.

Aortopulmonary window with anomalous origin of the right coronary artery.

We report a case of an aortopulmonary window with a right coronary artery arising from the pulmonary trunk. This exceedingly rare anomaly with anomalous coronary artery presented without myocardial ischemia owing to the aortopulmonary window. The correct diagnosis was made by angiography and a successful surgical correction was performed.

Age differences in effects of hypothermic ischemia on endothelial and ventricular function.

BACKGROUND: Prior studies indicate that immature myocardium has a greater tolerance to ischemia. Prior studies from our laboratory have shown that impaired postischemic endothelial function was correlated with reduced ventricular contractility, and that coronary endothelium has an important role in ischemia and reperfusion injury in neonatal hearts. METHODS: We examined the differences of endothelial function as well as ventricular function between immature and mature hearts in isolated blood-perfused lamb and sheep hearts after 2 hours of 15 degrees C cardioplegic ischemia. Three groups were defined according to age: neonatal ( < 1 week) hearts (n = 8), infant (1 month) hearts (n = 8), and adult (1 year) hearts (n = 6). Each of the three groups underwent a similar protocol including ischemic time, myocardial temperature, and cardioplegic solution. Based on earlier work, all had low perfusion pressures during the first 10 minutes of reperfusion. Thereafter the perfusion pressure was constant at 60 mm Hg in the neonatal hearts, 80 mm Hg in the infant hearts, and 100 mm Hg in the adult hearts to match the mean arterial pressure at each age in this species. RESULTS: At 30 minutes of reperfusion, the neonatal and infant hearts achieved significantly improved recovery of left ventricular systolic (maximum developed pressure and positive first time derivative of pressure, and volume normalized developed pressure and first time derivative of pressure) and diastolic (negative maximum first time derivative of pressure) functions and coronary blood flow. The postischemic endothelial function determined by the coronary vasodilator response to acetytlcholine was better in the neonatal and infant hearts compared with the adult hearts (p < 0.05). CONCLUSIONS: These results show that the immature hearts had better recovery of endothelial function and coronary blood flow as well as ventricular function compared with adult hearts after hypothermic ischemia and reperfusion. These results combined with previous studies add further support to the concept that events in the coronary vascular bed play an important role in reperfusion injury in both immature and mature hearts.

Fluorescence activated cell sorting: a reliable method in tissue engineering of a bioprosthetic heart valve.

BACKGROUND: Techniques of tissue engineering are used to seed human autologous cells in vitro on degradable mesh to create new functional tissue like a bioprosthetic heart valve. A precondition is subsequent seeding of native-valve-analogous pure endothelial and myofibroblast cell lines. The aim of this study is to find a safe method of isolating viable cell lines out of tissues from the operating room. METHODS: Mixed cells from ascending aorta obtained from the operating room were incubated with an endothelial-specific fluorescent marker. The labeled cells were activated and sorted by flow cytometry. Isolated cell lines were cultured and thereafter square sheets of polymeric scaffold were seeded with myofibroblasts, followed by endothelial cells. The created tissue was stained with hematoxylin and eosin, van Gieson stain, and stains for factor VIII and CD34. RESULTS: Control culture samples (n = 25) revealed vital uncontaminated endothelial and myofibroblast cell lines. Microscopy of the seeded meshes (n = 16) demonstrated a tissue-like structure. Van Gieson stain showed production of collagen. Endothelial cells formed a superficial monolayer, demonstrated by factor VIII and CD34; no invasive formation of capillaries was detectable. CONCLUSIONS: These results demonstrate that fluorescence activated cell sorting is a reliable and safe method to gain pure vital autologous cell lines out of human mixed cells for subsequent seeding on degradable mesh and that those cells are active to form new tissue.

Improved exposure of the pulmonary arteries for thromboendarterectomy.

Pulmonary thromboendarterectomy is a surgical technique for treating pulmonary hypertension caused by unresolved pulmonary embolism. It has been recommended to perform this procedure under deep hypothermic circulatory arrest. Here we describe two technical modifications: (1) improved exposure to the right pulmonary artery by division of the superior caval vein and (2) thromboendarterectomy in normothermic cardiopulmonary bypass, with beating heart or electrically induced ventricular fibrillation. These modifications allow complete endarterectomy of both pulmonary arteries under normothermic conditions, thus avoiding hypothermic circulatory arrest, which results in short cardiopulmonary bypass times and reduces the morbidity and mortality of this procedure.

Improved visualization in minimally invasive coronary bypass grafting.

A special surgical technique is required for minimally invasive coronary artery bypass grafting, particularly under beating-heart conditions. We describe a very simple system that provides improved visualization of the surgical site.

Tissue engineering heart valves: valve leaflet replacement study in a lamb model.

BACKGROUND: Valve replacements using either bioprosthetic or mechanical valves have the disadvantage that these structures are unable to grow, repair, or remodel and are both thrombogenic and susceptible to infection. These characteristics have significantly limited their durability and longevity. In an attempt to begin to overcome these shortcomings, we have tested the feasibility of constructing heart valve leaflets in lambs by seeding a synthetic polyglycolic acid fiber matrix in vitro with fibroblasts and endothelial cells. METHODS: Mixed cell populations of endothelial cells and fibroblasts were isolated from explanted ovine arteries. Endothelial cells were selectively labeled with an acetylated low-density lipoprotein marker and separated from the fibroblasts using a fluorescent activated cell sorter. A synthetic biodegradable scaffold constructed from polyglycolic acid fibers was seeded with fibroblasts, which grew to form a tissue-like sheet. This tissue was subsequently seeded with endothelial cells, which formed a cellular monolayer coating around the leaflet. Using these constructs, autologous (n = 3) and allogenic (n = 4) tissue engineered leaflets were implanted in 7 animals. In each animal the right posterior leaflet of the pulmonary valve was resected and replaced with an engineered valve leaflet. RESULTS: All animals survived the procedure. Postoperative echocardiography demonstrated no evidence of stenosis and trivial pulmonary regurgitation in the autografts and moderate regurgitation in the allogenic valves. Collagen analysis of the constructs showed development of an extracellular matrix. Histologic evaluation of the constructs demonstrated appropriate cellular architecture. CONCLUSIONS: This preliminary experiment showed that a tissue engineered valve leaflet constructed from its cellular components can function in the pulmonary valve position. Tissue engineering of a heart valve leaflet is feasible, and these preliminary studies suggest that autograft tissue will probably be superior to allogenic tissue.

Blockade of selectin-mediated leukocyte adhesion improves postischemic function in lamb hearts.

BACKGROUND: Leukocyte-endothelial interactions appear to have a important role in ischemia/reperfusion injury and are mediated by specific leukocyte and endothelial adhesion molecules. The selectins are adhesion molecules found on leukocytes (L-selectin) and endothelium (P and E selectin) that bind to oligosaccharide ligands containing fucose and sialic acid to mediate leukocyte rolling on the endothelium. Fucoidin is a nontoxic sulfated fucose oligosaccharide derived from seaweed that blocks the selectins. METHODS: We tested the effects of fucoidin in an isolated blood-perfused neonatal (age range, 3 to 7 days; mean age, 4.3 days) lamb heart model undergoing 2 hours of cold cardioplegic ischemia. In group F (n = 8) fucoidin (30 mg/L) was added at initial reperfusion. Group C (n = 9) received only cardioplegia with no reperfusion intervention. Isovolumic maximum developed pressure and the maximum positive and negative first derivatives of pressure were measured using a catheter-tip transducer in an intraventricular balloon before ischemia and at 30 minutes of reperfusion. Coronary blood flow, myocardial oxygen consumption, and white blood cell counts in the circulating blood were also measured. RESULTS: Percent recoveries of baseline maximum developed pressure and maximum positive and negative first derivatives of pressure in group F (86% +/- 5%, 81% +/- 10%, and 74% +/- 8%, respectively; mean +/- standard deviation) were higher than in group C (77% +/- 5%, 70% +/- 9%, and 65% +/- 6%; p < 0.05). Group F postischemic coronary blood flow was greater (190% +/- 35%) than in group C (102% +/- 10%; p < 0.05). Recovery of myocardial oxygen consumption in group F (86% +/- 14%) was greater than group C (72% +/- 11%; p < 0.05). Postischemic white blood cell count in group F (88% +/- 4%) was greater than in group C (81% +/- 5%; p < 0.05). CONCLUSIONS: Selectin blockade with fucoidin resulted in better recovery of left ventricular function, coronary blood flow, and myocardial oxygen consumption after cold ischemia, despite a higher circulating white blood cell count. These data support the hypothesis that endothelial-leukocyte interactions play an important role in ischemia/reperfusion and suggest that selectin blockade may be a useful therapeutic strategy.

Disadvantages of local repair in acute type A aortic dissection.

BACKGROUND: In acute type A dissection of the aorta, local repair with glue-aortoplasty was compared with aortic replacement. METHODS: Between 1992 and 1996, 106 consecutive patients (mean age, 59 years; 84 men) were operated on average 14.5 hours after onset of dissection. A local repair (gelatin-resorcine-formaldehyde/glutaraldehyde glue, Trigon AG, Monchengladbach, Germany) without graft replacement was performed in 21 patients. Graft replacement and reinforcement of aortic stumps with gelatin-resorcine-formaldehyde/glutaraldehyde glue was performed in 85 patients (supracoronary graft, 68; aortic root replacement, 17). RESULTS: Survival was 79% after 30 days and 69% after 2 years. There was no difference in early mortality (p = 0.2240) and survival (p = 0.07649). Risk factors for early mortality were preoperative shock, neurologic disorder, duration of crossclamp, and extracorporeal circulation. The rate of reoperation on the proximal aorta was 31.6% (6 of 19) after local repair and 9% (6 of 64) after aortic replacement (p = 0.0157). Local repair was a significant predictor for reoperation (p = 0.0087), with decreased reoperation-free survival (p = 0.01164). In all reinterventions (four supracoronary grafts, including two valve replacements; two composite grafts; two arch replacements) breakdown of the aortoplasty was confirmed. CONCLUSION: Local repair has satisfactory early results but an increased incidence of reoperations due to a breakdown of the glue-aortoplasty. Indications for local repair should be restricted to high-risk patients requiring a minimal emergency surgical procedure.

Complete thromboendarterectomy of the calcified ascending aorta and aortic arch.

BACKGROUND: Arteriosclerotic plaques of the ascending aorta and transverse arch increase the operative risk of cardiac operations and are strong predictors for late cerebrovascular events. METHODS: Twenty-two patients, mean age 68 +/- 6 years (range, 55 to 77 years), with grade IV + V plaques of the ascending aorta and transverse arch underwent coronary artery bypass grafting (n = 21) and aortic valve replacement (n = 8). Cerebrovascular emboli from unknown sources were found preoperatively in 8 patients (36%). All were in sinus rhythm. Complete thromboendarterectomy of the ascending aorta and transverse arch was performed during hypothermic circulatory arrest. After 21 +/- 12 months (range, 4 to 44 months), magnetic resonance imaging and transthoracic echocardiography of endarterectomized vessels was performed. RESULTS: There was one perioperative death (4.5%), one early (4.5%), and one late (4.7%) adverse neurologic event. Follow-up examinations revealed normal diameters of the endarterectomized aorta. CONCLUSIONS: For patients with grade IV + V plaques, thromboendarterectomy of the ascending aorta and transverse arch can be performed with an acceptable surgical risk and a low recurrence rate for cerebrovascular events. Dilatation of the endarterectomized aorta was not observed.

Preoperative administration of steroids: influence on adhesion molecules and cytokines after cardiopulmonary bypass.

BACKGROUND: Cardiopulmonary bypass (CPB) is associated with tissue damage mediated by adhesion molecules and cytokines. Prebypass steroid administration may modulate the inflammatory response, resulting in improved postoperative recovery. METHODS: Fifty patients undergoing elective coronary operations under normothermic CPB were randomized into two groups: group A (n = 24) received intravenous methylprednisolone (10 mg/kg) 4 hours preoperatively, and group B (n = 26) served as controls. Cytokines (tumor necrosis factor-alpha [TNF-alpha], interleukin-2R [IL-2R], IL-6, IL-8), soluble adhesion molecules (sE-selectin, sICAM-1), C-reactive protein, and leukocytes were measured before steroid application, then 24 and 48 hours, and 6 days postoperatively. Adhesion molecules were measured by enzyme-linked immunosorbent assay, cytokines by chemiluminescent immunoassay. Postoperatively, hemodynamic measurements, inotropic agent requirements, blood loss, duration of mechanical ventilation, and intensive care unit stay were compared. RESULTS: Aortic cross-clamp and CPB time was similar in both groups. Prednisolone administration reduced postoperative levels of IL-6 (611 versus 92.7 pg/mL; p = 0.003), TNF-alpha (24.4 versus 11.0 pg/L, p = 0.02), and E-selectin (327 versus 107 ng/mL, p = 0.02). Postoperative recovery did not differ between groups. CONCLUSIONS: Preoperative administration of methylprednisolone blunted the increase of IL-6, TNF-alpha, and E-selectin levels after CPB but had no measurable effect on postoperative recovery.

The use of an amniotic membrane graft to prevent postoperative adhesions.

Grafts of trypsin-treated, gamma-irradiated human amniotic membranes were used to cover injured uterine horns of nulliparous female rabbits to prevent adhesions. In this study, the gradual integration of the membranes into the serosal layer of the uterus, together with marked neovascularization, was observed. By the 30th postoperative day, the grafts had been completely integrated, with little evidence of rejection and no evidence of infection at the graft sites. Of 30 uterine horns treated with membrane grafts, only 4 (13.4%) showed any adhesion formation at or among the graft sites. All of the 24 untreated controls showed adhesion formation at the site of injury. Furthermore, whatever adhesions were found in membrane-treated horns could be graded as thin and filmy, accounting for less than 10% of the surface area of the graft, whereas the controls showed dense, thick adhesions covering 50% to 100% of the injured areas. We conclude that these specially prepared amniotic membranes are safe and effective in dramatically reducing postoperative adhesion formation in this animal model.

Treatment of internal mammary artery malperfusion syndrome by additional venous graft: early postoperative angiographic results.

BACKGROUND: Internal mammary artery malperfusion syndrome is caused by an acute imbalance between myocardial demand and nutritional support through the mammary artery. METHODS: We performed early angiography in 11 consecutive patients in whom the perioperative course suggested mammary artery malperfusion. All patients received an additional saphenous vein graft distally to the mammary artery anastomosis. RESULTS: Postoperative angiography revealed patent mammary artery and vein graft in 10 patients (three with a markedly reduced caliber of the arterial graft). CONCLUSION: Additional vein graft is the treatment of choice in mammary artery malperfusion syndrome; it does not lead to occlusion of the internal mammary artery.

Congenital subaortic stenosis by accessory mitral valve tissue, recognition and management.

Accessory mitral valve tissue as the single cause for left ventricular outflow tract obstruction is a very rare cardiac malformation in normally connected hearts. We report a case in which this condition was present as single cause for left ventricular outflow tract obstruction. The surgical technique is described and a review of the literature presented.

Tissue engineering in cardiovascular surgery: new approach to develop completely human autologous tissue.

OBJECTIVE: In cardiovascular tissue engineering, three-dimensional scaffolds serve as physical supports and templates for cell attachment and tissue development. Currently used scaffolds are still far from ideal, they are potentially immunogenic and they show toxic degradation and inflammatory reactions. The aim of this study is to develop a new method for a three-dimensional completely autologous human tissue without using any scaffold materials. METHODS: Human aortic tissue is harvested from the ascending aorta in the operation room and worked up to pure human myofibroblasts cultures. These human aortic myofibroblasts cultures (1.5x10(6) cells, passage 3) were seeded into 15-cm culture dishes. Cells were cultured with Dulbecco' s modified Eagle's medium supplemented with 1 mM L-ascorbic acid 2-phosphate for 4 weeks to form myofibroblast sheets. The harvested cell sheets were folded to form four-layer sheets. The folded sheets were then framed up and cultured for another 4 weeks. Tissue development was evaluated by biochemical assay and light and electron microscopy. RESULTS: After 4 weeks of culture in ascorbic acid supplemented medium, myofibroblasts formed thin cell sheets in culture dishes. The cell sheets presented in a multi-layered pattern surrounded by extracellular matrices. Cultured for additional 4 weeks on the frames, the folded sheets further developed into more solid and flexible tissues. Light microscopy documented a structure resembling to a native tissue with confluent extracellular matrix. Under transmission electron microscope, viable cells and confluent bundles of striated mature collagen fibers were observed. Hydroxyproline assays showed significant increase of collagen content after culturing on the frames and were 80.5% of that of natural human pericardium. CONCLUSIONS: Improved cell culture technique may render human aortic myofibroblasts to a native tissue-like structure. A three-dimensional completely autologous human tissue may be further developed on the base of this structure with no show toxic degradation or inflammatory reactions.

Conservative treatment of the aortic root in acute type A dissection.

OBJECTIVE: In acute type A dissection long-term results of conservative aortic root surgery were compared with the outcome of primary valve and/or root replacement. METHODS: Between 1985 and 1995, 199 patients (mean age 59 years, 154 men) were operated on. The aortic root was involved in the dissection process and valve incompetence of varying degree was present without exception. Replacement of a proximal aortic segment was standard procedure in all patients. The aortic valve was preserved in 126 patients: commissural suture resuspension (12 patients), root reconstruction with GRF-glue (gelatine-resorcin-formaldehyde/glutaraldehyde-glue) (114 patients). Valve replacement was performed in 73 patients (50 composite grafts, 23 valve prostheses with separate supracoronary grafts). Preoperative risk factors (valve replacement vs. preservation): coronary artery disease (11 vs. 8%, NS), tamponade (18 vs. 17%, NS), unstable hemodynamics (22 vs. 15%, NS), renal failure (4 vs. 6%, NS), neurologic disorder (19 vs. 32%, NS). RESULTS: The overall early mortality was 23.6% (47/199 patients) and increased after commissural suture resuspension compared with GRF-glue reconstruction (P = NS). Parameters of the early postoperative period did not differ between conservative treatment and root/valve replacement: low cardiac output, 34 versus 38% (P = NS); myocardial infarction, 10 versus 11% (P = NS); hemorrhage, 25 versus 23% (P = NS); duration of intensive care (P = NS). Survival was 61% after 8 years without difference between the two principal treatment groups (P = NS) and between the two conservative subgroups (P = NS). At 2 years, GRF-glue reconstruction had an increased freedom from reoperation on the aortic root (92 vs. 70%, P = 0.0253) and event free survival (77 vs. 41%, P = 0.0224) compared with suture resuspension. Commissural suture resuspension was an independent, significant predictor for reoperation (P = 0.0221, relative risk = 4.7130). CONCLUSION: Surgery for acute type A dissection still carries a considerable early risk. Preservation of the aortic root is safe in the absence of Marfan or annuloaortic ectasia, but a certain incidence of reoperations on the aortic valve and the aortic root has to be accepted. Root reconstruction using GRF-glue is the method of choice and is superior to suture resuspension, with a significantly better reoperation-free and event-free survival.