Procalcitonin levels after different types of conventional thoracic surgery.

BACKGROUND: Procalcitonin (PCT) is currently discussed as an indicator of postoperative complications following thoracic surgery. Serum levels of PCT are different after thoracoscopic and conventional surgical approaches. We conducted this study to test the hypothesis that different types of conventional thoracic surgery are associated with different postoperative serum levels of acute-phase proteins or pro-inflammatory mediators. METHODS: Serum levels of interleukin (IL)-6, C-reactive protein (CRP), lipoprotein-binding protein (LBP) and PCT were measured preoperatively (pre), immediately after surgery (0 h), 6 hours after surgery (6 h), and on the 1st (d1), 3rd (d3) and 5th (d5) postoperative days in 48 patients undergoing elective conventional pneumonectomy (n = 6), lobectomy (n = 20) or wedge resection (n = 22). RESULTS: In all study groups, IL-6 and PCT increased after surgery, peaking at 6 h and on d1, respectively. The time courses of IL-6, CRP, LBP and PCT release were not influenced by the type of surgical procedure. All parameters increased more markedly after lobectomy and wedge resection than after pneumonectomy. CONCLUSIONS: Surgical trauma and lung ischaemia/reperfusion injury could be the main factors determining the release of IL-6 and PCT after surgery. From an immunological point of view, pneumonectomy is less severe than wedge resection or lobectomy in terms of tissue injury. Different types of conventional thoracic surgery are associated with differences in postoperative PCT and IL-6 synthesis. For this reason, expected ranges of PCT and IL-6 levels should be established for the various surgical procedures before these parameters can be used as indicators of postoperative complications.

Immunoglobulin levels and lymphocyte subsets following cardiac operations: further evidence for a T-helper cell shifting.

BACKGROUND: Recent data indicate that cardiac surgery with cardiopulmonary bypass (CPB) results in an imbalance of T-helper cell subsets towards the anti-inflammatory pathway mediating humoral immune response. However, little is known about immunoglobulin levels as an important part of humoral immune response after CPB. Therefore, the objectives of this study were 1) to elucidate the effects of CPB on perioperative immunoglobulin levels, and 2) to find out if alterations in lymphocyte subsets are related to these findings. METHODS: Blood samples from 83 patients undergoing elective cardiac operation were taken preoperatively (d0), on the first (d1), third (d3), and fifth day (d5) after operation. Levels of immunoglobulin (Ig) E, IgM, and IgG, including the subclasses IgG 1 - 4, were measured. IgG2/IgE-ratio was used as indicator for TH1/TH2 shifting, and production of tetanus antibodies (AB) was investigated as an in vivo parameter of humoral immune reaction. The number and percentage of T- and B-lymphocyte subsets were assessed in a subgroup of 50 patients to answer the second question. RESULTS: Clinically, no mortality or major morbidity were observed. IgE levels did not change until d3 and increased significantly on d5. In contrast, both IgG and IgM levels decreased significantly on d1. While IgM returned to baseline (BL) on d5, IgG levels remained below BL until d5. IgG2/IgE-ratio decreased significantly on d1, reached its nadir on d3 and remained depressed until d5. The number of T-lymphocytes decreased on d1 as well as the number of B-cells. T-cells returned to BL on d5, B-cells on d3. However, while the percentage of T-cells decreased on d1, the percentage of B-cells increased. The percentage of T-cells returned to BL on d3, and B-cell percentage returned to BL on d5. Tetanus AB production did not change until d5 when it increased significantly. CONCLUSIONS: 1) Increase of IgE and tetanus AB production indicate that humoral immune response is not affected by CPB, but possibly even enhanced. The relative increase of B-cells is in line with this hypothesis. 2) Postoperative changes in immunoglobulin levels provide further evidence for a TH1/TH2-shifting. 3) The transient deficit in IgM-and IgG levels did not result in clinically adverse events. Thus, therapeutic intervention appears not to be required.

Alterations of cell-mediated immunity following cardiac operations: clinical implications and open questions.

Cardiac surgery with cardiopulmonary bypass (CPB) is known to induce an immune response whose nature has been increasingly elucidated during the recent decade. Clinically, patients usually show two to three of the four symptoms, which define the so-called systemic inflammatory response syndrome (SIRS). In addition, all parameters of the innate, nonspecific immune system, e.g., polymorphonuclear cells, elastase, and complement, are activated. This also applies to the proinflammatory mediators interleukin (IL)-1beta, -6, and -8, and tumor necrosis factor (TNF)-alpha. Within the adaptive, specific immune system, a decrease of T lymphocytes and T helper (TH) cells is observed, whereas suppressor/ cytotoxic T cells and B cells appear to be nearly unaffected. Cytokine measurements provide more detailed information: IL-2 and IL-12, which are important for the activation of the type-1 TH-cell (TH1)-mediated immune response, are depressed following cardiac operation. In contrast, IL-10 and transforming growth factor-beta essential to TH2-mediated humoral or anti-inflammatory immune response, are upregulated. In vivo tests, e.g., delayed type hypersensitivity skin reaction and tetanus antibody production, confirm the polarization of the adaptive immune response towards the TH2 pathway. However, all these alterations usually do not result in clinical adverse events. Therefore, more information is needed about the immune response of patients at high preoperative risk or with serious perioperative complications to find out whether clinically relevant events are correlated to alterations of immune response. For this purpose, more readily available, standardized methods for immunologic monitoring appear highly desirable.

Detection of acute phase response and infection. The role of procalcitonin and C-reactive protein.

OBJECTIVE: Established parameters, e.g. C-reactive protein (CRP), do not differentiate specifically enough between patients developing an infection and those exhibiting an acute phase response following cardiac surgery. The objective of this prospective study was to investigate if procalcitonin (PCT) is more helpful than CRP. METHODS: During a 1-year period, seven out of 563 patients (1.2%) developed systemic infections (group A) after cardiac operations with cardiopulmonary bypass (CPB), and additional eight patients (1.4%) had local wound infections requiring surgical therapy (group B). Blood samples for PCT and CRP measurements were taken preoperatively, at the onset of infection (d1), as well as on the third day (d3), fifth day (d5), and seventh day (d7) following diagnosis of infection. Forty-four randomly selected patients undergoing cardiac surgery with CPB without clinical signs of infection, additional intensive care unit (ICU) management or additional antibiotic treatment served as control (group C) to assess the PCT and CRP contribution to acute phase response. PCT and CRP levels were measured preoperatively, on the first (d1), third (d3) and fifth day (d5) after operation. RESULTS: At the onset of infection, PCT levels (median interquartile range 25%-75%) increased significantly in group A as compared to baseline values (10.86 (3.28-15.13) ng/ml vs. 0.12 (0.08-0.21) ng/ml), and decreased during treatment to still significantly elevated values on d5 (0.56 (0.51-0.85) ng/ml). CRP levels were significantly elevated on all days investigated with no trend towards normalisation (d1: 164.5 (137-223) mg/l) vs. 1.95 (1.1-2.8) mg/l preoperatively, d5: 181.1 (134-189.6) mg/l. In group B, no increase in PCT levels, but a significant increase of CRP from d1 (165.9 (96.6-181.6) mg/l) vs. 3.7 (2-4.3) mg/l preoperatively) until d5 98 (92.8-226.2) mg/l was detected. In group C, postoperative PCT levels increased slightly but significantly in the absence of infection on d1 (0.46 (0.26-0.77) ng/ml vs. 0.13 (0.08-0.19) ng/ml preoperatively), and d3 (0.37 (0.2-0.65) ng/ml and reached baseline on d5 (0.24 (0.11-0.51) ng/ml)). CRP levels were significantly elevated as compared to baseline on all postoperative days investigated (baseline: 1.75 (0.6-2.9) mg/l, d1: 97.5 (74.5-120) mg/l), d3: 114 (83.05-168.5) mg/l, d5: 51.4 (27.4-99.8) mg/l)). PCT showed a significant correlation to CRP in group A (r =0.48, p < 0.001), a weak correlation in group C (r=0.27, p=0.002) and no correlation in group B. Intergroup comparison revealed a significant difference for PCT between all groups (A>C>B) and significantly higher CRP levels in group A vs. C and in group B vs. C. Thus, the pattern high PCT/high CRP appears to indicate a systemic infection, while low PCT/high CRP indicates either acute phase response or local wound problems, but no systemic infection. The cost for PCT measurements was 5.6-fold higher as compared to CRP. CONCLUSION: Due to the significant differences in the degree of increase, PCT appears to be useful in discriminating between acute phase response following cardiac surgery with CPB or local problems and systemic infections, with additional CRP-measurement increasing the specificity.

Early extubation after cardiac surgery: a prospective clinical trial including patients at risk.

BACKGROUND: Recent evidence suggests that early extubation after cardiac surgery can be performed without increased morbidity, resulting in economic advantages. However, most studies on this subject exclude patients with preoperative risk factors described as predictors for prolonged mechanical ventilation. The purpose of our prospective clinical trial was to decide whether early extubation is feasible independent of preoperative patient status, in particular independent of preoperative risk factors. METHODS: From 12/96 to 6/97, 266 patients underwent cardiac surgery, most commonly CABG and valve replacement. 65 patients (24.4%) formed the risk group, showing preoperatively at least one of the following risk factors: emergency surgery, severe left-ventricular dysfunction, previous heart surgery, recent myocardial infarction, age 75 years or older, history of several myocardial infarctions. The remaining 201 patients (75.6%) formed the control group. The percentage of patients extubated within 12 hours represented the primary endpoint. 38 patients (10 risk, 28 control) had to be excluded from further analyses due to intra- or perioperative complications. RESULTS: No differences between 55 risk patients and 173 control patients could be detected in extubation rate within 12 hours (100% vs 100%), mean extubation time (6:04 h vs 6:01 h), and incidence of complications after extubation (5.5% vs 5.2%). Risk patients were discharged 0.33 days later from the intensive care unit (2.00 d vs 1.67 d; p = 0.047). CONCLUSIONS: 1. All patients are basically suitable for early extubation, with the presence of preoperative risk factors used in this study being poor predictors of prolonged ventilation. 2. The necessity of prolonged ventilation is primarily determined by intra- or perioperative complications.

Influence of anodal electrode position on transvenous defibrillation efficacy in humans: a prospective randomized comparison.

Nonthoracotomy lead systems for implantable cardioverter defibrillators (ICDs) have reduced operative mortality and morbidity as compared to epicardial lead systems but are usually associated with higher defibrillation thresholds (DFTs). The purpose of this prospective randomized trial was to investigate if the second defibrillation electrode in the left subclavian vein can increase defibrillation efficacy and decrease DFT as compared to the superior vena cava (SVC) position in nonthoracotomy lead systems for ICDs. Seventeen patients (mean age: 49.9 +/- 11.3 years, mean ejection fraction: 46.1% +/- 15.8%) were implanted with an investigational unipolar electrode (Medtronic 13001) used as the defibrillation anode. DFT testing was started in the SVC (n = 10, group A) or the left subclavian vein (n = 7, group B), and repeated in the alternative position starting at the DFT of the initial position. Fifteen patients were eligible for analysis (group A: n = 9, group B: n = 6). With the electrode in the SVC, ventricular fibrillation could be successfully terminated in 9 out of 15 patients (60%). In the left subclavian vein the success rate was 100% (P < 0.01). Mean DFT in the SVC was 13.0 +/- 5.2 J and in the left subclavian vein 10.2 +/- 4.9 J. DFTs in the left subclavian vein were either lower (group A: n = 5/9, group B: n = 5/6) or equal to the results in the SVC position (P < 0.001). Thus, the left subclavian vein appears to be a superior alternative for positioning of the defibrillation anode as compared to the SVC for nonthoracotomy lead systems using two separate leads.

An imbalance in T-helper cell subsets alters immune response after cardiac surgery.

Growing evidence indicates that cell-mediated immunity is altered after cardiac surgery with cardiopulmonary bypass (CPB). The objective of this prospective randomized study was to investigate (1) if an imbalance in T-helper cell (TH) subsets, i.e. TH1/TH2, may be responsible for these alterations and (2) if they can be counteracted. Twenty patients formed control group A. Twenty group B patients received indomethacin and thymopentin for immunomodulation. In vitro tests included measurements of TH, interleukin (IL)-2 as a cytokine primarily produced by TH1 cells, and IL-6 as a cytokine primarily produced by TH2. Delayed-type hypersensitivity (DTH) skin response and specific antibody (AB) production were used as in vivo tests for TH1- and TH2-induced immune response, respectively. Postoperatively, group A patients showed a persistent, significant reduction of TH, IL-2 synthesis and DTH skin response as compared to baseline values, while IL-6 synthesis remained unaltered and AB production increased (P < 0.05). In group B patients no change in TH, IL-2 and IL-6 synthesis, or DTH skin response was observed (P < 0.05 vs A). Postoperative AB production increased significantly in group B. These results indicate a significant suppression of TH1-induced cell-mediated immune response following CPB, while TH2-induced response remains normal. A normal TH2 response may be helpful for recovery following cardiac surgery by cleaning the body of the byproducts of CPB. A suppression of TH1 response may gain clinical significance whenever a postoperative infection requires this response, but can be effectively counteracted by immunomodulatory intervention with indomethacin and thymopentin.

Determinants of dual chamber pulse generators longevity.

The aim of this study was to investigate the effect of battery capacity, internal current drain, and stimulation energy on pulse generators longevity, and if battery impedance measurements can reliably predict pulse generators end-of-life. For this purpose, the records of 577 patients with a mean age of 65 +/- 14 years who had undergone implantation of two different dual chamber pulse generators (PG1: 409; PG2: 168) were retrospectively reviewed. Battery capacity were 2.3 Ah (PG1) and 3.0 Ah (PG2) while current drain at comparable nominal settings was 20 microA (PG1) and 30 microA (PG2) indicating a higher internal current drain of PG2. After a mean follow-up of 46 +/- 23 months, stimulation energy at reprogrammed output settings was significantly higher in PG1 as compared to PG2 (17.1 +/- 0.14) vs 15.5 +/- 0.24 J). Three PG1 (0.7%) and 12 PG2 (7.1%) (P < 0.01) had to be exchanged after a mean of 77.3 +/- 5.3 months (PG1) and 75 +/- 13.5 months (PG2) (P = NS) due to end-of-life being reached. The difference in battery impedances of PG1 and PG2 gained statistical significance 5 years after implantation (1.0 k omega vs 2.4 +/- 6.7 k omega) preceding the significant difference in PG survival after 6 years (98.7 +/- 1.3% vs 90.7 +/- 4.8%). These results indicate that internal current drain is the most important determinant of the pulse generators longevity and that battery impedance can reliably predict end-of-life. Therefore, the essential information about internal current drain should be available for each pacemaker, since it is required for adequate pulse generator selection. Diagnostic functions of dual chamber pulse generators should include measurements of battery impedance.

The left subclavian vein as an alternative site for implantation of the second defibrillation lead.

The optimal placement for the second defibrillation lead in a two-lead system has never been addressed. We retrospectively reviewed the data of 33 patients with an average age of 59.2 years (range 41-78 years), predominantly male (n = 29), who underwent implantation of a cardioverter defibrillator (ICD) for treatment of ventricular tachycardia (n = 19) or ventricular fibrillation (n = 14). In all patients an attempt was made to implant an endovenous ICD device (leads only, no subcutaneous patch). In group I (n = 18) the defibrillation anode, a separate unipolar lead, was placed in the common position, the superior vena cava. In group II (n = 15) the lead was placed in the left subclavian vein. At least two consecutive shocks reverting ventricular fibrillation at energies < or = 24 J were required for implantation of the ICD device. All shocks were monophasic. The success rate of endovenous defibrillation was significantly higher in group II than in group I (67% vs 28%, P < 0.05). Thus, it could be demonstrated that the position of the defibrillation anode can influence the defibrillation efficacy in transvenous ICD systems. Prospective randomized trials are needed to investigate the optimal position for the second defibrillation electrode, which may gain increasing importance as soon as dual chamber ICDs become available.

Comparison of porcine biological valves with pericardial valves--a 12-year clinical experience with 1123 bio-prostheses.

In order to evaluate selective differences of biological porcine valves versus pericardial valves and to analyze various valve models, 8 different bioprostheses (4 porcine valves, 4 pericardial valves) were studied in a 12-year follow-up. From 1978 to 1990, 476 porcine bioprostheses (Carpentier-Edwards: n = 104, Carpentier Edwards Supraanular: n = 59, Hancock I: n = 41, Hancock II: n = 272) and 647 pericardial valves (Hancock-Extracorporeal: n = 479, Ionescu-Shiley: n = 76, Carpentier-Edwards: n = 57, Mitroflow: n = 35) were implanted. At time of implantation, the patient age ranged from 21-85 years, mean 57.1 +/- 12.4 years. 831 patients were analyzed in the long-term follow-up (62.3 +/- 18.6 months, cumulative follow-up of 6632 patient-years). The incidences of thromboembolic complications (TE), endocarditis (E), primary tissue failure (PTF), rate of reoperation (ReOp), and late mortality due to prosthesis dysfunction were analyzed, calculated, and compared within the different valve models (actuarial data, chi 2 test, log rank analysis). The incidences of TE and E were lower for pericardial valves when compared with porcine bioprostheses (TE: 0.88 vs. 1.8%/patient year; E: 0.24 vs. 0.5%/patient year); within the 2 groups, the different valve models did not show any major differences. However, the incidence of PTF was significantly higher in the pericardial valve group, being 36 +/- 6.5%, 68 +/- 10% and 86 +/- 19.5% after 6, 8, and 10 years; the respective figures for the porcine valves were 6 +/- 3.5%, 18 +/- 7.1%, and 60 +/- 13.1% (p < 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)

One-incision approach for insertion of implantable cardioverter defibrillators.

The placement of a transvenous implantable cardioverter defibrillator (ICD) system through a single infraclavicular skin incision has been a surgical goal for years. The development of a new investigational model of ICD with substantially reduced dimensions (volume, 83 cm3; mass, 132 g) has made the one-incision approach a clinical reality. Between March and September 1993, 4 female and 19 male patients (mean age, 60 +/- 9.6 years; range, 46 to 73 years) underwent implantation of this device for the treatment of ventricular fibrillation (n = 14) or ventricular tachycardia (n = 9). One transvenous lead was placed in the right ventricular apex and another in the left subclavian vein. A subpectoral pocket was formed in the infraclavicular area from the same incision to house the ICD generator and, if necessary, the subcutaneous patch. The mean operation time (81.5 +/- 32.7 minutes; range, 54 to 195 minutes) was significantly shorter than that noted for a previous series made up of patients undergoing traditional transvenous ICD implantations. In 20 patients (87%), endovenous defibrillation without a subcutaneous patch successfully caused externally induced ventricular fibrillation to revert with a mean minimum energy output of 21.9 +/- 3.5 J (range, 12 to 24 J). Endovenous defibrillation was more successful when biphasic (n = 16/17 [94%]) shocks rather than monophasic shocks (n = 4/6 [67%]) were used. No mortality, morbidity, or surgical complications were observed. These results indicate that the one-incision approach and the small size of the ICD generator can substantially facilitate ICD implantation and result in a reduction in the surgical trauma, the operation time, and the amount of material implanted.

Homograft aortic root replacement for destructive valve endocarditis. The benefit of an in-house homograft bank.

This report concerns the surgical treatment of a 45-year old patient with active staphylococcus-endocarditis of the aortic valve which resulted in an aortic root abscess and consequently in a ventricular aortic discontinuity. A technique of homograft aortic root replacement after removal of all infected and necrotic areas is described. After a six month follow-up, the patient is asymptomatic (New York Heart Association functional class I) and shows no signs of recurrence of endocarditis. This case report makes the benefit of an in-house homograft-bank system obvious.

Endothelialization of cardiac valve bioprostheses.

The main disadvantage of implanted xenograft valves used in cardiac surgery is their poor clinical long-term result, due to early tissue degeneration. In order to improve the performance of such glutaraldehyde fixed bioprostheses, a biological coating with viable endothelial cells was suggested. Therefore, glutaraldehyde preserved bovine pericard patches, as well as commercially available xenograft valves, were lined using human venous endothelial cells or microvascular cells from the subcutaneous fat tissue. Before cells were transplanted into their new environment, grafts were treated with an amino acid solution in order to neutralize the cytotoxic effect of free aldehydes, and precoated with fibronectin-heparin and basic fibroblast growth factor (bFGF) or endothelial cell growth supplement (ECGS) in order to enhance cell proliferation. Coated specimens were kept in culture conditions for a further seven days. Proliferation of transplanted cells was verified by an increase of activation following 3H-thymidine incorporation, while the maintained metabolic cell activity was demonstrated via Prostacycline (PGI2) measurement. Morphology was evaluated by means of scanning electron microscopy (SEM). As evaluated by the beta-Counter, 7 ng/ml bFGF (288,727 +/- 39,668 counts on day 4) substantially enhanced cell proliferation after seeding, opposed to the stimulation with 30,000 ng/ml ECGS (91,924 +/- 1129 counts on day 4), (p < 0.001). The PGI2 release of transplanted cells was stimulated with 25 microM Na arachidonic acid by the factor 2.6 +/- 0.3 and inhibited with 5 mM acetylsalicylic acid by the factor 0.7 +/- 0.2 on day 4 when compared with the basic level.(ABSTRACT TRUNCATED AT 250 WORDS)

Studies of the nucleoside transporter inhibitor, draflazine, in the human myocardium.

1. The aim of the present study was to determine the effect of the nucleoside transporter inhibitor, draflazine, on the force of contraction in human myocardium and the affinity of the compound for the nucleoside transporter. Nucleoside transport inhibitors, like draflazine, are of potential importance for cardiopreservation of donor hearts for heart transplantation. 2. Functional experiments were performed in isolated electrically driven (1 Hz, 1.8 mmol l-1 Ca2+) human atrial trabeculae and ventricular papillary muscle strips. The affinity of draflazine for the myocardial nucleoside transporter was studied in isolated membranes from human ventricular myocardium and human erythrocytes in radioligand binding experiments using [3H]-nitrobenzylthioinosine ([3H]-NBTI). Dipyridamole was studied for comparison. 3. In membranes from human myocardium and erythrocytes, [3H]-NTBI labelled 1.18 pmol mg-1 protein and 23.0 pmol mg-1 protein, respectively, nucleoside transporter molecules with a KD value of 0.8 nmol l-1. Draflazine concentration-dependently inhibited binding of [3H]-NBTI to myocardial and erythrocyte membranes with a K(i)-value of 4.5 nmol l-1. The potency as judged from the K(i) values was ten times greater than that of dipyridamole in both myocardial and erythrocyte membranes. 4. Draflazine, at concentrations up to 100 mumol l-1, did not produce negative inotropic effects in atrial and ventricular myocardium. (-)-N6-phenylisopropyladenosine (R-PIA) and carbachol did not reduce force of contraction in ventricular myocardium, but exerted concentration-dependent direct negative inotropic effects in atrial myocardium. 5. The data provide evidence that draflazine specifically binds to the nucleoside transporter of the human heart and erythrocytes with high affinity. The compound does not produce negative inotropic effects at concentrations as high as 100 micromol 1-1.6. Draflazine could be a useful agent for cardio preservation because it does not produce cardio depressant effects. Thus, it may be possible to perfuse explanted hearts directly with this agent without the hazard of cardiodepression.

New morphologic aspects of explanted Hancock Extracorporeal pericardial bioprostheses.

Between 1981 and 1987 a total of 479 Hancock Extracorporeal bovine pericardial bioprostheses were implanted in 458 patients. During the time period from 1990 to 1993, 21 valves, 15 in the aortic and six in the mitral position, had to be removed 72 to 109 months after implantation. The mean age of these patients at the time of implantation was 49.7 +/- 10.5 years. All 21 removed as well as one unimplanted bioprosthesis were morphologically investigated. Visual examination, radiography, histology and ultrastructural observations were performed using scanning and transmission electron microscopy. In addition, clinical data were correlated to morphological findings. All valves failed due to cusp tears originating at the stent posts. Calcification was minimal in five valves, moderate in 10, and severe in five valves. Only one valve showed no mineralization at all. The late morphologic changes were associated with thickening of valve leaflets, tissue delamination, calcification, degeneration of collageneous network, and extensive insudation of plasma proteins and lipids. The present findings suggest that denatured collagen molecules may be capable of inducing immune response.

Comparison of UW versus HTK solution for myocardial protection in heart transplantation.

In order to evaluate the protective effect of University of Wisconsin (UW) solution in heart transplantation, a retrospective comparative study with histidine-tryptophane-ketoglutarate (HTK) solution was initiated. In group I, we included 160 patients with HTK preservation, while group II consisted of 50 patients who had their transplant protected with UW solution. All patients received standard quadruple drug therapy for immunosuppression. The average ischaemic time of the donor hearts in group I was 142+/-44 min, ranging from 83 to 235 min. Acute immediate perioperative graft failure occurred in six cases (3.8%). Statistical analysis including the chi-square test, revealed a significant increase in the incidence of acute perioperative graft failure when compared with duration of ischaemic time (P < 0.01). Within the first 30 postoperative days, 24 patients died (15% early mortality). The same statistical correlation was evident between the incidence of early mortality and duration of graft ischaemic time. The 30-day and 6-month survival rates were 81% and 78%, respectively. The average ischemic time of the donor hearts in group II was 193+/-50 min ranging from 100 to 360 min, which was significantly longer in comparison with the group I (P < 0.05). Acute perioperative graft failure occurred once (2%); the patient was retransplanted successfully. Five patients died within the first 30 postoperative days (10% early mortality). There was no correlation between length of ischaemic time and incidence of acute graft failure or early mortality. The 30-day and 6-month survival rates were 90% and 88%, respectively and, thus, better when compared with group I. In both groups similar results were achieved with regard to postoperative NYHA status of the patients and incidence of cardiac arrhythmias. Myocardial preservation with HTK solution showed satisfying results as long as the ischaemic time did not exceed 4 h. The early functional results achieved with UW graft protection were excellent, even with ischaemic times longer than 4 h and not depending on lenght of ischaemic period.

Registration of thoracic electrical bioimpedance for early diagnosis of rejection after heart transplantation.

In this study, registration of thoracic electrical bioimpedance was used for early detection of acute rejection after heart transplantation. Thirty-five heart transplant recipients were monitored by registration of thoracic electrical bioimpedance signals during the immediate postoperative period and during the outpatient follow-up. At the same time, endomyocardial biopsy specimens were taken. In addition to cardiac stroke volume index and ejection fraction, the acceleration index (seconds -2) was calculated. This acceleration index describes the acceleration of blood volume and represents a function parameter of the myocardial inotropy. Seventeen acute rejection episodes were diagnosed during the follow-up period. The average acceleration index value during the 17 rejection episodes was 92.5 +/- 11.7 sec-2 and thus significantly lower when compared with the nonrejection levels (p < 0.05). The acceleration index values decreased during acute rejections by an average of 36.4 +/- 19.3 sec-2 (28%). The sensitivity of this diagnostic parameter in the examined patients was 71%, and the specificity was 100%. Thus registration of thoracic electrical bioimpedance and calculation of the acceleration index represents a quick and noninvasive monitoring technique and can ideally be used in the outpatient clinic as a supplement to invasive endomyocardial biopsies.

Long-term results of pacemaker therapy after orthotopic heart transplantation.

The objectives of this study were to identify: (1) the indications for pacemaker implantation; (2) the long-term survival; (3) the percentage of bradyarrhythmias below 50 beats/min persisting for more than 3 months; and (4) the variables predicting persistent bradyarrhythmias following orthotopic heart transplantations. During the recent decade (August 1, 1981 through December 31, 1991), 237 patients underwent orthotopic heart transplantation at our institution. Twenty-six recipients (11%) showed evidence of a symptomatic bradyarrhythmia due to sinus node dysfunction (n = 25) or complete heart block (n = 1), which required insertion of a permanent pacing device. During a mean follow-up period of 17.2 months (range 3 to 57 months), five patients (19%) died and one was lost to follow-up. Actuarial survival at 1 and 4 years were 81% and 65%, respectively, as compared to 79% and 69%, respectively, in patients without permanent pacemakers. Holter monitoring after 3 months (n = 25) and 1 year (n = 14) showed a spontaneous heart rate below 50 beats/min in six (24%) and three patients (18%), respectively. None of the tested variables predicted the necessity of initial pacemaker implantation. However, in patients requiring permanent pacing for a period longer than 3 months, ischemic time of the donor heart was found to be significantly longer as compared to the other patients (221 +/- 76 min vs 137 +/- 91 min, p < 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)