Hans-Georg Borst

Systemic inflammatory response syndrome after cardiac operations

BACKGROUND A systemic inflammatory response after open heart operation may be responsible for hyperdynamic circulatory instability and organ dysfunction. To what extent mediator release is involved needs to be clarified. METHODS Ten patients with postoperative hyperdynamic circulatory dysregulation (group I) requiring application of alpha-constrictors and 10 patients with routine cardiac procedures and stable postoperative hemodynamic indices (group II) were analyzed for mediator release and metabolic and hemodynamic changes until the third postoperative day. RESULTS Group I patients showed a significantly increased cardiac index and decreased systemic vascular resistance after bypass (cardiac index, group I: 5.2 +/- 1.2 L.min-1.m-2, group II: 2.5 +/- 1.6 L.min-1.m-2; systemic vascular resistance, group I: 495 +/- 204 dyne.s. cm-5, group II: 1,356 +/- 466 dyne.s.cm-5) and at 3 hours (cardiac index, group I: 4.4 +/- 0.8 L.min-1.m-2, group II: 2.9 +/- 0.6 L.min-1.m-2; systemic vascular resistance, group I: 567 +/- 211 dyne.s.cm-5, group II: 1,053 +/- 273 dyne.s.cm-5). Significantly higher serum levels of interleukin-6 were assessed in group I (postbypass, group I: 6,812 +/- 9,293 pg/mL, group II: 295 +/- 303 pg/mL; 3 hours, group I: 3,474 +/- 5,594 pg/mL, group II: 286 +/- 296 pg/mL). Concentrations of elastase, tumor necrosis factor, soluble tumor necrosis factor receptor, and interleukin-8 were elevated in group I (not significant). Early postoperative levels of soluble E-selectin and soluble intercellular adhesion molecule were also higher in group I (not significant). Continuously increased levels of endotoxin could be detected in only 3 of 10 patients in group I. Severe lactic acidosis (> or = 5 mmol/L) occurred in group I only. CONCLUSIONS Postoperative hyperdynamic instability after open heart operations appears to be associated with a certain pattern of mediator release. In particular, interleukin-6 appears to be involved in circulatory dysregulation and metabolic derangement.

Steal phenomenon caused by a parallel branch of the internal mammary artery

We report on a patient with postoperative mammary artery steal resulting from a parallel branch of the vessel as well as from a patent first left intercostal artery, both of which had not been divided. The patient was cured of angina pectoris after embolization of both vessels.

Biophysical properties of the gelatin-resorcinformaldehyde/glutaraldehyde adhesive

Refixation of dissected aortic layers with gelatin-resorcin-formaldehyde/glutaraldehyde (GRFG) adhesive represents a new option in the surgical treatment of aortic dissection. Because of its ability to reinforce the delicate structures of the acutely dissected aortic wall, GRFG has been used increasingly in recent years. However, the biomechanical properties of the adhesive are still unclear, and little is known regarding the optimal mode of its application. In an ex vivo study, aortic specimens from sheep were glued with warm (45 degrees C) adhesive under wet and dry conditions and submitted to defined degrees of compression (5 Newtons [N], 20 N). Bonded specimens were retracted to assess tensile strength and elasticity compared with two reference adhesives: cyanoacrylate gel and fibrin glue. Gelatin-resorcin-formaldehyde/glutaraldehyde and cyanoacrylate gel showed similar results at 5 N. Both provided better adhesion when applied under dry conditions (GRFG 5 N: dry, 3.5 +/- 1.6 N/cm2; wet, 1.4 +/- 1.0 N/cm2; cyanoacrylate gel 5 N: dry, 4.8 +/- 1.8 N/cm2; wet, 3.2 +/- 1.3 N/cm2). At 20 N, GRFG tensile strength was significantly increased for either condition compared with values at 5 N (GRFG 20 N: dry, 17.1 +/- 4.2 N/cm2; wet, 4.8 +/- 1.8 N/cm2). Fibrin glue demonstrated only weak adhesive properties even under dry conditions (fibrin glue 5 N: dry, 0.8 +/- 0.3 N/cm2). Gelatin-resorcin-formaldehyde/glutaraldehyde has good adhesive properties both in wet and dry tissue. Bonding capacity can be substantially increased when applied on dry surfaces and at increased pressures.

Open Heart Operations After Renal Transplantation

BACKGROUND Because of the increasing number of renal transplantations performed, secondary cardiac operations in these patients are discussed concerning their impact on patient and graft survival. METHODS We reviewed our experience in 45 patients (33 male and 12 female) who underwent open heart operations after previous renal transplantation. Thirty-one patients (group I) received coronary artery bypass grafting and 14 (group II) underwent valve replacement. Mean age at the time of operation was 55 +/- 9 years. The interval between renal transplantation and cardiac operation was 57 +/- 39 months (range, 5 days to 174 months). All patients had functioning renal allografts with preoperative serum creatinine levels ranging from 100 to 338 mol/mL (mean +/- standard deviation, 195 +/- 86). RESULTS Overall early operative mortality (30 days) was 8.8% (group I, 1 patient; group II, 3 patients). Underlying causes of death were septic endocarditis (n = 2, group II), necrotizing enterocolitis (n = 1, group I), and myocardial infarction (n = 1, group II). One further patient in group II also died of septic endocarditis after 69 days (in-hospital death). The mean follow-up of the 40 surviving patients was 44 +/- 31 months. There was another late death (24 months postoperatively) caused by coagulopathy. Four patients had returned to hemodialysis at intervals of 27 to 83 months (mean, 51 months) because of renal transplant failure. In all patients, the function of the renal allograft was not impaired by open heart operation. CONCLUSIONS Open heart operations in renal transplant recipients have acceptable mortality and morbidity rates. In almost all patients, function of the transplanted organ can be maintained at the preoperative level.

Perioperative complications in combined aortic valve replacement and extraanatomic ascending-descending bypass

BACKGROUND In adult patients, the combination of severe aortic valve stenosis and coarctation is rare. Surgical options comprise either a two-stage approach with valve replacement and subsequent repair of the coarctation or a one-stage repair involving valve replacement and insertion of an extraanatomic bypass graft from the ascending to the descending aorta. METHODS We report the cases of 2 adult patients with this combined lesion who underwent simultaneous aortic valve replacement and transpericardial bypass of the coarctation. RESULTS Weaning from extracorporeal circulation and restoration of spontaneous circulation required resuscitative measures. By increasing mean arterial perfusion pressure using norepinephrine, the observed hemodynamic instability could be controlled effectively. CONCLUSIONS Changes in the hemodynamics of the thoracic vascular bed resulting in coronary malperfusion are discussed to be the major cause of heart failure and life-threatening ventricular arrhythmias seen in our patients after aortic valve replacement and insertion of an ascending-descending aorta bypass graft. Awareness of the complications described is considered important for successful management of these high-risk patients.

Papillary fibroelastoma of the aortic valve presenting with myocardial infarction

We describe the case of a 56-year-old woman who presented with myocardial infarction. Noninvasive and invasive investigations revealed coronary embolism from a papillary tumor attached to the right coronary cusp of the aortic valve as the underlying process. The tumor, which histologically proved to be a papillary fibroelastoma, was excised surgically and the resulting defect in the aortic valve leaflet was closed with a patch of autologous pericardium, effectively reconstructing the aortic valve. The current literature on intracardiac papillary fibroelastoma as a source of embolism and its surgical treatment is summarized.

Histopathological evaluation of woven and knitted Dacron grafts for right ventricular conduits: a comparative experimental study.

Composite extracardiac conduits consisting of a low-porosity woven graft and a high-porosity knitted double-velour Dacron graft presealed with fibrin glue were implanted between the right ventricle and the pulmonary artery in 6 dogs under partial heparinization. Two grafts were explanted after 6 weeks, 2 after 12 weeks, and 2 after 6 months. The healing properties of both types of prosthesis were studied macroscopically, under light microscopy, and with scatter electron microscopy. Spontaneous peeling of both the inner and outer capsules of the graft occurred in 3 of 6 woven prostheses during transection. In the remaining 3, peeling could be easily induced by blunt dissection; this was impossible in the knitted grafts. Microscopically, in a comparison of the different weaves after identical time intervals, the inner capsule was noticeably thicker in woven than in knitted grafts. Transtitial ingrowth of fibroblastic tissue could be observed in knitted grafts after 6 weeks; only poor transmural tissue bridging was detectable in woven prostheses after 6 months. Neovascularization of the inner capsule was detectable earlier and was more advanced toward the luminal surface of highly porous grafts. In conclusion, knitted grafts in the position of extracardiac right ventricular conduits showed firmer attachment of both inner and outer capsules to the prosthetic material. Also, the inner capsule remained thinner and revealed a higher degree of neovascularization than in the woven Dacron grafts.

REPAIR OF FLAIL ANTERIOR LEAFLETS OF TRICUSPID AND MITRAL VALVES BY CUSP REMODELING

We present an alternative approach to extensive rupture of the chordae tendineae leading to flail anterior leaflets. Resection of the affected cusp segment, suture of the cut edges, and extensive plication of the segment of annulus devoid of leaflets abolished massive regurgitation while maintaining an adequate valve orifice.

Extracorporeal membrane oxygenation (ECMO): extended indications for artificial support of both heart and lungs.

Extracorporeal membrane oxygenation (ECMO) was used to achieve temporary artificial support in cardiac and pulmonary function in 22 patients from 1987 to September 1990. Standard indications were postcardiotomy cardiogenic shock (n=4), neonatal (n=1) and adult respiratory distress syndrome (n=4). ECMO was also used for extended indications, such as graft failure following heart (n=11) or lung transplantation (n=2). In six of these cases ECMO was instituted as a bridge device to subsequent retransplantation of either the heart (n=4) or one lung (n=2). One out of nine patients supported by ECMO for standard indications, and two out of 13 patients supported for extended indications are long-term survivors. This series illustrates the results with ECMO in emergency situations, in patients under immunosuppressive protocols, or in patients with advanced lung failure requiring almost complete artificial gas exchange. In such complex situations, ECMO does provide stabilization until additional therapeutic measures are in effect. ECMO cannot be recommended for postoperative cardiogenic shock but short-term ECMO support is an accepted method in most cases with graft failure or pulmonary failure or other origin.

In vivo evaluation of the Lillehei-Kaster heart valve prosthesis.

In vivo evaluation of the Lillehei-Kaster heart valve prosthesis was performed in 28 patients; 22 had undergone aortic valve replacement and 6 had had mitral valve replacement. Mean pressure gradients ranged from 6 to 53 mm Hg in aortic prostheses; valve area varied from 0.83 to 2.9 cm2. The maximum opening angle of 80 degrees was never reached in this group of patients; opening angles ranged from 57 to 74 degrees without evidence of disc malfunction. There was no correlation between the ratio of effective to geometric valve area and the degree of opening of the disc occluder. Similar results were found in the mitral valve group. Gradients ranged from 6.0 to 12.5 mm Hg and valve area from 1.6 to 2.2 cm2. The maximum opening angle was 59 to 63 degrees. It is concluded that incomplete opening of the disc occluder in pivoting-disc valves is not necessarily a sign of disc malfunction. Lillehei-Kaster valves smaller than 18 mm in internal diameter should be avoided in adults, and outflow aortoplasty for implantation of a larger prosthesis should be used in patients who have a narrow aortic root.