Development of cell oedema in piglet hearts during ischaemia monitored by dielectric spectroscopy.

OBJECTIVE: The aim of this research was to investigate if dielectric spectroscopy between 100 Hz and 1 MHz provides reliable information about water distribution in ischaemic heart tissue and to investigate the influence of temperature on oedema formation. METHODS: We examined hearts of landrace piglets (n = 13) during ischaemia at 35 °C, 25 °C, and 15 °C. The dielectric permittivity ε'(f) and conductivity σ'(f) were calculated from impedance spectra measured between 100Hz and 1MHz. Gap junction uncoupling (GJU) was identified in the sigmoidal time course of ε'(13 kHz). The extracellular space index (ECSI) was estimated by the ratio σ'(100 Hz)/σ'(1 MHz). Intercalated water was analysed in electron microscopy images of the myocardial samples and was used to calculate the extracellular space index ECSIhisto. The ECSI and ECSIhisto were compared during ischaemia. GJU and oedema formation were simulated with an electrical heart model. RESULTS: At the onset of ischaemia, the ECSI was significantly higher than the ECSIhisto (p < .01). GJU during ischaemia was temperature-dependent. After GJU, the values of the ECSI and ECSIhisto matched very well. The simulations confirmed the influence of GJU on the ECSI. SIGNIFICANCE: The estimation of cell oedema with the ECSI is reliable only after GJU. The development of oedema estimated by the ECSI was delayed at cooler temperatures.

Implantation of left ventricular epicardial leads in cardiosurgical patients with impaired cardiac function--a worthwhile procedure in concomitant surgical interventions?

BACKGROUND: Cardiac resynchronization therapy (CRT) by means of multisite biventricular pacing is an effective therapeutic option for the treatment of severe heart failure. The present study estimates how many open heart-surgery patients could benefit from the implantation of permanent left ventricular (LV) pacing leads. After routine preoperative screening, epicardial electrodes were implanted in selected patients. Lead performance and outcomes were investigated. METHODS: Primarily, 1059 patients were retrospectively investigated with regard to LV function, left bundle branch block and QRS duration. Afterwards, suitable patients were identified and epicardial electrodes [Medtronic 5071 (ME) or Enpath (EP)] were implanted during concomitant procedures. Mean follow-up time was 6.3 ± 5.5 months. RESULTS: The retrospective study showed that 24 patients (2.3%) could potentially profit from CRT. After routine preoperative screening for CRT-responders, 22 patients (1.6%) were identified who finally received epicardial leads. No complications occurred. Acute capture threshold was 0.9 ± 0.4 V (ME, n = 17) and 0.5 ± 0.2 V (EP, n = 5). While leads in 18 patients were implanted as an upgrade to an existing pacemaker or implantable cardioverter-defibrillator (ICD) technologies (Group B), 4 patients underwent prophylactic implantation with no device attached (Group A). CRT-ICDs were implanted at follow-up in 3 Group A patients (75%). In Group B patients, the QRS duration decreased (from 189 ± 35 ms to 152 ± 16 ms, p < 0.02) and their postoperative mean NYHA functional class improved significantly (2.2 ± 0.5 versus 2.8 ± 0.6). CONCLUSION: A small group of cardiac surgery patients may benefit from LV-lead implantation during concomitant procedures. A protocol for responder identification is useful. Existing devices should be upgraded to CRT systems. As CRT-ICD implantation is frequent, the additional costs and time are justified.

Therapeutic optimization of atrioventricular delay in cardiosurgical ICU patients by noninvasive cardiac output measurements versus pulse contour analysis.

BACKGROUND: Optimizing atrioventricular (AV) delay improves cardiac output and postoperative outcome. Impedance cardiography (ICG) is a non-invasive method for CO measurement. This study evaluates the ability of two ICG methods to determine the optimal AV delay (OAVD) and to compare ICG with invasive PICCO measurements. METHODS: In 14 cardiosurgical ICU patients (age 70.4 +/- 12.0 yrs) with temporary pacing wires, OAVD was determined by pulse contour analysis (PICCO) and ICG (conventional ICG [CI] and electrical velocimetry [EV] ICG monitors). Cardiac output (CO) and stroke volume (SV) were measured during DDD pacing with AVD varying from 70 to 270 ms in 20-ms increments. RESULTS: Measured OAV showed a linear correlation between PICCO and ICG: CI (r = 0.82, P < 0.0002) and EV (r = 0.84, P < 0.0002). The mean OAVD deviation between PICCO and ICG was 15.7 +/- 21.0 ms (CI) and 17.1 +/- 20.5 ms (EV). Hemodynamic parameters (SV increase OAVD against worst case) improved significantly (+ 11.7 +/- 7.2 %, P < 0.0001). CONCLUSION: Inappropriate selection of AVD can compromise the hemodynamic situation of cardiosurgical patients. As it is totally noninvasive, ICG is a reliable and effective tool for tailoring AVD. Both systems (CI and EV) offer valid OAV determination.

Interleukin-6 enhancement after direct autologous retransfusion of shed thoracic blood does not influence haemodynamic stability following coronary artery bypass grafting.

BACKGROUND: Direct autologous retransfusion of shed thoracic blood is carried out to reduce homologous transfusion after cardiac surgery, but it contains high concentrations of inflammatory mediators. The purpose of the study was to investigate whether retransfusion of shed thoracic blood induces plasma interleukin-6 (IL-6) expression and influences haemodynamics. METHODS: Following uncomplicated coronary artery bypass graft surgery, forty-four patients were randomised in case postoperative blood loss via thoracic drains exceeded 350 ml. The course of plasma IL-6 levels and haemodynamics including cardiac output, extravascular lung water and intrathoracic blood volume were investigated prior to (T0), 30 minutes (T1), 1 (T2), 3 (T3) and 12 hours (T4) after retransfusion of 350 ml shed blood in comparison to 350 ml saline. RESULTS: Plasma IL-6 levels at T1 (1892 +/- 202 vs. 485 +/- 30 pg/ml) and T2 (1059 +/- 119 vs. 413 +/- 30 pg/ml) were significantly higher in the verum group (n = 20) compared to controls (n = 24) ( P < 0.01). Severe haemodynamic side effects were not detected. CONCLUSION: This study found significantly elevated plasma IL-6 levels following direct autologous retransfusion of shed thoracic blood but failed to show severe adverse effects affecting haemodynamic stability.

Tissue resident C reactive protein in degenerative aortic valves: correlation with serum C reactive protein concentrations and modification by statins.

OBJECTIVE: To assess aortic valve probes for valvar C reactive protein (CRP) presence, the relation between valvar and serum CRP, and a possible modification of CRP by statin medication. SETTING: Tertiary referral centre. PATIENTS AND DESIGN: End stage, degenerative valve tissue was taken from 81 patients, 57 with non-rheumatic aortic valve stenosis (AS) and 24 with degenerative aortic valve bioprosthesis (BP). Five non-stenosed valves served as controls. Tissue from four non-implanted bioprostheses was also examined. The presence and location of CRP was analysed by use of immunostaining and morphometry. Serum CRP concentrations were measured preoperatively. RESULTS: The majority of AS and BP valves exhibited CRP labelled cells, predominantly localised to the valvar fibrosa. The expression of CRP was much higher in BP than in AS (by a factor of 3.7, p = 0.03). Notably, non-stenosed aortic valves and non-implanted bioprostheses did not have CRP signalling. Serum CRP was also increased with BP (by a factor of 2.5, p = 0.02) and was significantly correlated with valvar CRP expression (r = 0.54, p < 0.001). The main finding in patients with (n = 26) and without statin treatment (n = 55) was that both valvar CRP expression (p = 0.02) and serum CRP concentrations (p = 0.04) were lower in the statin treated group. CONCLUSIONS: CRP was found in a large series of degenerative aortic valves, more often in bioprostheses than in native cusps. Serum CRP concentrations may reflect inflammatory processes within the aortic valve. The association of statin treatment with decreases in both valvar and serum CRP concentrations may explain known pleiotropic effects of statins in patients with aortic stenosis.

Do we still need CK-MB in coronary artery bypass grafting surgery?

AIM: The aim of this study was to evaluate the role of cardiac Troponin I (cTnI) and CK-MB for early prediction of outcome of patients undergoing coronary artery bypass grafting (CABG) surgery. METHODS: In 134 consecutive patients undergoing CABG-surgery blood samples were analyzed for cTnI concentration and CK-MB activity. ECG, hemodynamic parameters and the need for inotropic support, were continuously registered. Patients were divided into group A (uneventful course), group B (ischemia by ECG, hemodynamic stability) and group C (ischemia by ECG and IABP). RESULTS: After removal of X-clamp an increase cTnI and CK-MB was observed in all patients. Five hrs after stop of CPB group A (8.3+/-4.2 microg/L) had lower cTnI values compared to group B (14.8+/-5.3 microg/L) (p=0.035) and C (54+/-22.8 microg/L) (p=0.023). The cut off value was 14.8 microg/L. Sensitivity and specificity (99%/97%) was higher for cTnI than for CK-MB (90%/30%). The positive predictive value of outcome was better for cTnI (86%) than for CK-MB (33%). CONCLUSION: CTnI is a specific and sensitive marker for evaluation of perioperative myocardial ischemia (PMI). Additional determination of CK-MB activity does not provide further clinical information. CTnI should be the marker of first choice in CABG surgery.

[Chlamydia pneumoniae and cytomegalovirus in degenerative aortic valve stenoses]. / Chlamydia pneumoniae und Zytomegalie-Virus in degenerativen Aortenklappenstenosen.

Recent evidence suggests a causal relationship between inflammatory as well as infectious pathomechanisms and valvular degeneration. Based on the concept of chronic Chlamydia pneumoniae and cytomegalovirus (CMV) infections, and of variable stressors working on valvular microecology, the present study sought to assess the presence of the specific chlamydial heat shock protein (cHSP) 60, of CMV, of macrophages and of the human homologue hHSP60. Serial sections of high-grade degenerated native (n = 16) and prosthetic (n = 6) aortic valves were analyzed by immunohistochemistry for the presence of these determinants. Degenerated aortic valves revealed prevalence of Chlamydia pneumoniae in 41% (10 of 22) and CMV in 73% (16 of 22), while immunoreactive hHSP60 was present in 64% (14 of 22) and CD68 in 86% (19 of 22). Chlamydial HSP60, CMV and hHSP60 were predominantly found in valvular fibrosa; CMV showed a second predilection site at the ventricular luminal border. Both microorganisms revealed a strong correlation between each other (r = 0.73; p < 0.001) as well as with hHSP60 (cHSP60: r = 0.74; p < 0.001; CMV: r = 0.80; p < 0.001). Macrophage infiltration correlated with cHSP60 (r = 0.78; r < 0.001), CMV (r = 0.78; r < 0.001) and hHSP60 (r = 0.56; r = 0.007). Of note, the frequency of cHSP60, CMV and CD68 signaling was increased more than 5-fold in prosthetic valves compared to native valves (p = 0.017, p = 0.002 and p = 0.005). In summary, valvular infections of Chlamydia pneumoniae and of cytomegalovirus are frequently seen in degenerated aortic valves, irrespective of native or prosthetic origin. Colocalization of both HSP60 homologues and cytomegalovirus within macrophages in valvular fibrosa points to regional stressor effects that might be at least partly attributable to chronic persistent pathogen burden and molecular mimicry.

Surgical management of complications caused by transcatheter ASD closure.

BACKGROUND: Transcatheter occlusion of uncomplicated atrial septum defects (ASD) is recognized as an effective and minimally invasive method. Sometimes, serious early and late complications require surgical intervention. We therefore investigated reasons and outcomes of the secondary surgical approach. METHODS: 5 patients (aged 5-73 yrs) were admitted to our institution for device explantation and surgical ASD closure. ASDOS devices (A devices) had to be explanted in 4 patients and a SIDERIS "buttoned" occluder (S device) had to be explanted in 1 patient. The period from transcatheter implantation to surgical explantation ranged from 1 hour to 3 years. RESULTS: 3 patients (60 %) had to be operated in an emergency setting. In our youngest patient (5 yrs), the A device separated and embolized into the aorta and pulmonary artery. A pregnant women who needed emergent cesarean section developed hemopericard and tamponade due to atrial perforation by a fractured leg of an A device. In another A device, a suspect endocarditis caused membrane perforation. Malpositioning of an S device was the reason for operation. All patients recovered well without neurological symptoms. CONCLUSIONS: Transcatheter closure of uncomplicated ASD is a feasible alternative but surgical stand-by is essential. Nevertheless more complicated ASD should be operated, especially since the cosmetically satisfactory techniques of minimal invasive heart surgery are available.

[Transthoracic echocardiography in endocarditis: a comparison of conventional and harmonic echocardiography]. / Transthorakale Echokardiographie bei Endokarditis: Vergleich von konventioneller und harmonischer Echokardiographie.

BACKGROUND AND OBJECTIVE: Compared with conventional echocardiography (CEC) harmonic imaging (HEC) provides better resolution of the endocardial line and valvular apparatus. This prospective study was undertaken to compare the value of harmonic and conventional transthoracic echocardiography in endocarditis and compare them with standard transoesophageal echocardiography (TOE) and operative findings. PATIENTS AND METHOD: Conventional and harmonic echocardiographic imaging was compared in 30 patients (aged 58 +/- 17 years; 19 males and 11 females) with endocarditis clinically judged to require surgical intervention. The results of both methods were then compared with those of standard TOE and the intraoperative findings. RESULTS: Intraoperatively 15 floating structures, 9 abscesses and 5 perforations were demonstrated. Transoesophageal echocardiography was better than the standard method in diagnosing floating structures and detecting abscesses (15 vs. 10 vegetations, p < 0.05; 7 vs. 5 abscesses, p = 0.05). TOE was better than either method in the diagnosis of abscess. CONCLUSION: Harmonic transthoracic echocardiography is better than the conventional mode in diagnosing complications of endocarditis.

[Preoperative mortality of heart surgery patients]. / Präoperative Letalität kardiochirurgischer Patienten.

Cardiac surgery is principally joined to mortality at or because of waiting lists. In a retrospective study patients of either sex were analyzed, who died preoperatively during period A (1980-1984) or during period B (1988-1992). During A 100 patients died while during B 136 died, although the total numbers of open heart procedures were similar during both periods. Demographic data show that during B more patients with CHD died than during A. In both periods most of the patients could be assigned to NYHA/CCC classes III (71% (A) vs 64% (B)). Mean age increased from 55.7 to 62.8 years being the only significant parameter to differ (p < 0.001). The portion of urgent operations increased to 53.7% during B. The analysis of time intervals demonstrates that the interval from invasive diagnosis until announcement for operation and the interval from announcement until death were significantly shortened (p > 0.02). The increasing age and progredient morbidity may be responsible for this phenomenon. Preoperative mortality increased significantly from 2.0% (A) to 2.7% (B) in the total group, as well as in the subgroups. For patients with CHD the mean mortality was 2.3% and for patients with aortic valve disease it was 4.3% during B. The analysis of morbidity and mortality of patients dying at the waiting list is strongly required, since mortality rates of the total and the subgroups are unexpectedly high and not acceptable.

[Changes in indications for surgical coronary revascularization 1985 to 1992]. / Wandel der Indikationsstellung zur operativen Koronarrevaskularisation in den Jahren 1985 bis 1992.

We analyzed the changing use of coronary artery bypass grafting in our institution during the years from 1985 to 1992. All clinical parameters indicating an increased perioperative risk for the surgical intervention increased during the study period (increased percentage of old patients, females, patients with severe coronary artery disease (high modified Gensini-index or triple-vessel disease), and left main stenoses). During a 2-year follow-up there was a constant proportion of patients with a good postoperative clinical result; perioperative mortality as well as global and cardiac 2-year mortality showed no significant changes. Despite an increased proportion of patients with higher perioperative risk the acute and long-term results of coronary artery bypass surgery in our study were quite satisfactory. This must be attributed to improvements in operative techniques, improved personal skills of the surgeons, and improvements in perioperative treatment and critical care.

[Acute coronary artery occlusion after elective percutaneous transluminal coronary angioplasty. Incidence and therapy in 5000 consecutive patients]. / Akuter Koronargefässverschluss nach elektiver perkutaner transluminaler Koronarangioplastie. Inzidenz und Therapie bei 5000 konsekutiven Patienten.

Five thousand consecutive percutaneous transluminal coronary angioplasties (PTCA) were electively performed between January 1988 and June 1993. They were analysed for the incidence of acute coronary occlusion, its acute treatment and subsequent course. In 133 patients (2.7%) the occlusion persisted. Recanalization by repeat PTCA was attempted in all of them, but succeeded in only 68 (51%). In 65 patients recanalization was impossible. In 25 of the latter--patients with a small infarct vessel and infarction having already occurred in the vessel's supply area while the haemodynamics remained stable--conservative treatment was practised. Acute surgical revascularization was undertaken in 30 patients (23%) with a large area and/or haemodynamic instability. In all, 14 patients died (overall death rate 0.28%, death rate of patients with occlusion 11%), ten of them before operative intervention was possible.--Not all coronary artery occlusions can be treated nonsurgically. Consequently, availability of surgical intervention at the place of elective PTCA is mandatory.

[Preservation of the posterior mitral valve leaflet and effect on follow-up results after additional mitral valve implantation]. / Erhalt des posterioren Mitralsegels und Einfluss auf das Spätergebnis nach zusätzlicher Mitralklappen-Implantation.

As early as 1964, Lillehei et al. published the technique of preservation of the posterior mitral leaflet (PML) and chordae tendineae in combination with mitral prosthesis implantation (MPI). In a limited randomized number of 95 patients with MPI the influence of preservation of PML on hemodynamics and physical capacity at least 46 months after surgery without (group A) and with preservation of PML (group B) was investigated. Statistically significant differences in favor of group B were found for cardiac index, pulmonary artery pressure after stress, end-diastolic volume index (EDVI), physical capacity and survival rate after a complication-free course. Basing on these results at rest and after exertion (30 W), patients with preservation of PML and MPI are long-term in a better clinical condition.

[Long-term results of surgical therapy of thoracic aortic aneurysm (dissection of the ascending aorta)]. / Langzeitergebnisse der chirurgischen Therapie bei thorakalen Aortenaneurysmen (A. ascendens-Dissektion).

Thoracic aneurysms are classified according to the nomenclature of De Bakey (1-3b) or Daily (Stanford A-B). Our early and late results refer to dissections of the ascending aorta with and without aneurysms as well as with and without aortic valve involvement. The distal extension of the dissections was different. Since 1979 45 patients (mean age 48 years, range 23-70 years) were operated, the acute dissections mostly as emergencies after secured diagnosis. The preferred technique was reconstruction of the ascending aorta. However, also other techniques as prosthetic replacement or implantation of an conduit were used. The hospital lethality was 12.5% (n = 6); the late letality 24% (n = 7). The cumulative survival rate after 8 years was 74%.