Joachim Cremer

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.

The use of gelatin-resorcin-formalin glue in acute aortic dissection type A

OBJECTIVES The Gelatin-resorcin-formalin (GRF) glue is widely used in the surgical treatment of dissecting aneurysms. This paper is focused on our experience with the GRF glue in cases, operated for acute aortic dissection type A. METHODS Between September 1990 and December 1997, 164 patients were operated on for acute aortic dissection type A. In 148 patients GRF was used to reinforce the dissected layers proximal (n = 106) or distal (n = 144) of the grafted aortic segment. An intervention at the aortic valve was necessary in 93 instances. In 111 patients, an open distal anastomosis for replacement of the proximal aortic arch was performed. Thirty-seven additional patients underwent subtotal or total aortic arch replacement. RESULTS Early postoperative mortality was 26.2% (43/164 patients). Another 16 patients died late postoperatively. Actuarial survival rates are 69.9% at 1 year, 62.5% at 3 years, 59.4% at 5 years and 56.1% at 7 years, post-operatively. Twenty-two reoperations were performed in 20 patients (16.5%). Nine of these patients had developed complications in aortic segments that underwent reconstruction by use of GRF during the primary intervention. Aortic root redissection was found in 7/9 patients intraoperatively, whereas 1/9 patients presented with a rupture near the distal graft to aortic anastomosis. CONCLUSIONS The introduction of GRF glue has greatly facilitated the reconstruction of dissected aortic wall layers adjacent to the vascular graft. However, the use of the adhesive for aortic root reconstruction in acute aortic dissection type A may bear a significant risk of late postoperative proximal aortic redissection. Complications associated with the GRF glue are likely to be due to the toxic effects of the formalin component. Therefore, care should be taken that the amount of formalin administered to the glue components remains as low as possible.

Surfactant replacement in reperfusion injury after clinical lung transplantation

Background: Reperfusion injury remains a significant risk factor in the immediate postoperative course after lung transplantation. We report on our initial clinical experience of surfactant replacement in reperfusion injury after clinical lung transplantation. Methods and results: In 31 consecutive patients, lung (8 single lung, 16 bilateral lung) or heart-lung (7) transplantation was performed. In 6 patients, severe reperfusion injury developed and was treated with continuously nebulized surfactant. Compliance of the allograft increased 40 ± 25 % within 3 h following treatment with surfactant. Alveolar arterial oxygen gradient decreased by 23 ± 11 % after 3 h and by 35 ± 20 % after 6 h. Normal graft function was reestablished within 1–3 days after transplantation. All treated recipients were extubated until the 6th postoperative day. The 30-day mortality for the 31 recipients was 3.3 %, the 1-year survival 84 %. Conclusions: Surfactant replacement may become a clinical method for treatment of reperfusion injury after lung transplantation.

NEBULIZED SYNTHETIC SURFACTANT IN REPERFUSION INJURY AFTER SINGLE LUNG TRANSPLANTATION

Reperfusion injury is one of the major causes of early morbidity and mortality after lung transplantation. Features of thi s syndrome are pulmonary edema, reduction of compliance, and impaired gas exchange, and these occur in about 20% of all lung transplant recipients. Usual treatment includes prolonged mechanical ventilation with elevated positive end-expiratory airway pressure (PEEP), enhanced mean airway pressure with high oxygen content (Fio2), and, in severe cases, inverse ratio ventilation and extracorporeal membrane oxygenation. We report on the successful treatment with nebulized synthetic surfactant (Exosurf; Wellcome, Burgwedel, Germany) of a patient in whom reperfusion injury developed 5 hours after right lung transplantation. Right lung transplantation was done in a 26-year-old woman who had sarcoidosis with terminal interstitial lung disease and recurrent failure of the right side of the heart. The patient had been dependent on continuous oxygen insufllation for 30 months before transplantation. Pulmonary hypertension was present with a mean pulmonary artery pressure of 50 mm Hg.

Left ventricular function, tricuspid incompetence, and incidence of coronary artery disease late after orthotopic heart transplantation.

Functional results and data concerning the incidence and severity of graft atherosclerosis (GASC) and tricuspid incompetence (TI) in the intermediate term after orthotopic heart transplantation (HTX) are still striking. We examined 92 patients 1, 2, and 3 years after HTX by right and left heart catheterization in order to evaluate pump function, the status of the coronary arteries and the extend of TI, using a double indicator thermodilation technique. Mean left ventricular volumes and ejection fraction were normal 1 and 2 years post-transplant. The incidence of GASC was 8/87 (9.2%) at 1, and 11/92 (12%) at 2 years. It was more frequent (16%) in patients with preexisting coronary artery disease (IHD) than in patients with underlying dilative cardiomyopathy (DCM) (11%). At the end of the 1st postoperative year, 62% of patients were free of TI, whereas only 38% had normal valve function 2 years posttransplant. In 9/14 (64%) of patients, consecutively assessed at 1 and 2 years, TI had increased between both investigations. Preoperative haemodynamics, the number of endomyocardial biopsies and rejection episodes as well as preoperative cardiac size did not correlate with TI. Left ventricular volumes and ejection fraction are normal in the intermediate term after HTX. The incidence of GASC was less than 10% at 1 year and did not significantly increase thereafter. TI is a frequent and yet unexplained finding after HTX showing a considerable tendency to increase with time, but with little or not haemodynamic consequence.

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.

Previous Open Heart Operation: A Contribution to Impaired Outcome After Cardiac Transplantation?

BACKGROUND There is still debate about whether previous cardiac operations are a risk factor for patient outcome after cardiac transplantation. As waiting lists for cardiac transplantation increase, adverse outcome criteria should be identified. METHODS To assess this problem, we retrospectively analyzed 53 patients with previous cardiac operations before heart transplantation and compared them with 53 control patients matched for sex and age. Patient groups were analyzed regarding their preoperative, intraoperative, and postoperative variables and survival. RESULTS Ischemic times were comparable in both groups, but the duration of the operation was significantly longer in the study group (206.5 +/- 62.5 minutes, versus 156.0 +/- 36.7 minutes in controls; p < 0.05). In addition, postoperative blood loss was greater for the patients with previous cardiac operations (1,360 +/- 260 mL, versus 730 +/- 310 mL for controls; p < 0.01). Postoperatively, the rate of rejection episodes and the incidence of graft atherosclerosis were comparable within the first 2 years. However, survival was significantly reduced in the study group (60.1%) after 4 years (versus 83.1% for controls; p < 0.05). CONCLUSIONS Heart transplantation in patients with previous cardiac operations will lead to an impaired overall outcome. In addition, these patients have more postoperative complications.

Pneumocystis carinii pneumonia following heart transplantation.

Pneumocystis carinii pneumonia represents a rare complication that is associated with a high mortality following heart transplantation. The cases of two heart transplant recipients who developed Pneumocystis pneumonia within the first 3 postoperative months are reported. Both patients had severe clinical symptoms of the disease; the diagnosis was confirmed by bronchoalveolar lavage, and the patients were treated with a combination of trimethoprim and sulfamethoxazole. Both patients recovered and are well at the time of this report.

Distant organ procurement in clinical lung- and heart-lung transplantation : cooling by extracorporeal circulation or hypothermic flush. Discussion

The scarcity of suitable donors for single lung and heart-lung transplantation calls for methods of medium-term pulmonary preservation to allow for distant organ procurement. At our institution, the first five grafts (four heart-lung, one single lung) were cooled by means of a transportable extracorporeal circulation unit, while the last eight grafts (four heart-lung, four single lung) were flush-perfused with modified cold Euro-Collins solution. The technique of extracorporated circulation included aortic and right atrial cannulation and cooling to 12 degrees-14 degrees C (rectal temperature) using a bubble oxygenator. Bypass times ranged between 41 and 52 min. Following excision, the organs were transported in ice-cold donor blood for ischemic times from 171 to 310 min. For cold flush preservation, simultaneous coronary (cold St. Thomass solution) and pulmonary artery perfusion (Euro-Collins solution, 50 ml/kg over 4 min) were initiated simultaneously. The organs were transported in cold Euro-Collins solution for ischemic times of 175 to 270 min. In heart-lung transplantations the first postoperative arterial PO2 upon arrival at the intensive care unit was 120 +/- 38 Torr in the extracorporeal circulation and 140 +/- 38 Torr in the Euro-Collins solution group. Six of eight patients were extubated within 48 h after cardiopulmonary grafting. We conclude that pulmonary function following heart-lung or single lung preservation with simple hypothermic flush is as good or better than that following extracorporeal circulation. Since distant organ retrieval is much more convenient without the latter, preservation using Euro-Collins solution is preferred.

Early postoperative flow rates after internal thoracic artery grafting for the left coronary artery system

OBJECTIVE The low perioperative flow rates of internal thoracic artery (ITA) conduits have been regarded as a limitation of their use in critical coronary situations with a high myocardial blood demand. To clarify whether these restrictions are justified, early postoperative flow rates were determined. METHODS Following bilateral ITA grafting, 48 of 106 patients (April 1993-September 1994) underwent recatheterization. Subsequent to control angiography between days 8 and 12, 20 of these patients were studied by intravascular Doppler techniques applied for ITA grafts supplying the left anterior descending artery (LAD) and branches of the circumflex system (CX) (n = 20). Doppler spectral analysis allowed for determination of the average peak velocity and diastolic-systolic velocity ratio. Vascular diameters were assessed by simultaneously performed quantitative angiography and mean flow rates were calculated. All parameters were recorded at rest and following selective stimulation with nitroglycerin (0.2 mg) and papaverine (12.5 mg) to evaluate the graft flow capacity. RESULTS Baseline values of average peak velocity at rest were 24.6 +/- 11.5 cm/s for ITA-LAD conduits and 21.9 +/- 6.8 cm/s for ITA-CX pedicles. Following dilative stimulation with papaverine, a significant increase in average peak velocities were obtained for both locations (ITA-LAD: 47.3 +/- 17.1 cm/s, ITA-CX: 42.3 +/- 11.8 cm/s). The application of nitroglycerin had a similar effect (ITA-LAD: 42.6 +/- 15.3 cm/s, ITA-CX: 40.3 +/- 10.7 cm/s). The vascular diameters of ITA conduits remained unchanged on nitroglycerin stimulation, whereas papaverine effected significant dilatation in both locations. Flow rates at rest were not significantly different (ITA-LAD: 51.0 +/- 34.2 ml/min, ITA-CX: 44.7 +/- 16.4 ml/min) and maximal flow increase was observed following papaverine stimulation of the LAD conduits (116.1 +/- 90.6 ml/min). Dilative stimulation effected an increase in diastolic-systolic velocity ratios from average values at rest in a range between 34% and 41.7% for both groups and substances. CONCLUSIONS The basic blood flow in functioning ITA grafts appears to be similar in conduits supplying the LAD and marginal branches. Flow rates between 50 and 60 ml/min at rest should meet myocardial demands, even in the LAD position. Increased flow rates were predominantly based on higher flow velocities with an increased diastolic flow proportion. Enlargement of the graft diameter may exert additional effects, at least following papaverine stimulation at a particular concentration.