Surgical Myocardial Revascularization with a Composite T-graft from the Left Internal Mammary Artery-Comparison of the Great Saphenous Vein with the Radial Artery.

BACKGROUND: Composite T-grafts between left internal mammary artery (LIMA) and radial artery (RA) are a common concept in complete arterial myocardial revascularization. The aim of the present study was to investigate whether the use of the great saphenous vein (SV) instead of RA leads to comparably good results in terms of outcome in this context. METHODS: Patients who underwent myocardial revascularization with a T-graft using RA or a segment of SV to the right coronary artery or circumflex artery between the beginning of 2014 and the end of 2019 at the Department of Cardiovascular Surgery, University Hospital Schleswig-Holstein, Campus Kiel were included. To minimize surgical variation, only patients were observed by a single senior surgeon in the department. Exclusion criteria were previous cardiac surgery, preoperative extracorporeal circulatory support, off-pump surgery, additional aortocoronary bypasses, and cardiac combination procedures. RESULTS: A total of 115 patients were studied. In 55 patients, the T-graft was placed between the LIMA and SV, and in 60 patients, the T-graft was placed between the LIMA and RA. Patients in the SV group were older (70.6 ± 7.8 vs. 58.5 ± 10.0 years; p < 0.001), suffered more frequently from non-ST elevation myocardial infarction (12.7 vs. 1.7%; p = 0.027), arterial hypertension (83.6 vs. 61.7%; p = 0.009), and atrial fibrillation (18.2 vs. 1.7%; p = 0.003). They were less likely to be active smokers (16.4 vs. 38.3%; p = 0.009) and less likely to have a history of variceal surgery (0 vs. 15.0%; p = 0.003). Calcification of the ascending aorta was also found more frequently in the saphenous group (18.2 vs. 3.3%, p = 0.009). Operative times and number of distal anastomoses did not differ significantly between the two groups. Postoperative deliriums (16.7 vs. 5.0%; p = 0.043) were observed more frequently in venous patients. Wound healing disorders of the leg (11.1 vs. 0%; p = 0.011) did only occur in SV group and wound infections of the arm only in the RA group. Complete follow-up was achieved in 74.8% of cases. Median follow-up was 60.3 (39.6; 73.2) months. Serious adverse cardiac-cerebral events (19.0 vs. 22.7%; p = 0.675) and mortality (14.5 vs. 6.7%; p = 0.167) did not differ significantly between the groups at follow-up. Myocardial infarction (0 vs. 2.5%; p = 1.000) and stroke (0 vs. 7.5%; p = 0.245) were observed exclusively in RA group. Percutaneous coronary intervention was required in single patients of RA group (0 vs. 15.0%; p = 0.028). No patient from either group underwent repeat coronary artery bypass grafting (CABG). The patients of SV group had angiographically competent grafts and open anastomoses. Graft failure was noted in a single patient in RA group, in which case both grafts and native coronary vessels were stented. Kaplan-Meier analysis revealed no significant survival disadvantage for SV group compared with RA group. CONCLUSION: CABG with a composite T-graft between LIMA and a segment of SV may be comparable to bypass surgery with a composite T-graft between LIMA and RA. This might be true in terms of morbidity and mortality over an intermediate-term observation period. The results of our studies give rise to the hypothesis that the decision not to perform aortic bypass anastomosis may be more important than the choice of graft material.

SELNET clinical practice guidelines for bone sarcoma.

Bone sarcoma are infrequent diseases, representing < 0.2% of all adult neoplasms. A multidisciplinary management within reference centers for sarcoma, with discussion of the diagnostic and therapeutic strategies within an expert multidisciplinary tumour board, is essential for these patients, given its heterogeneity and low frequency. This approach leads to an improvement in patient's outcome, as demonstrated in several studies. The Sarcoma European Latin-American Network (SELNET), aims to improve clinical outcome in sarcoma care, with a special focus in Latin-American countries. These Clinical Practice Guidelines (CPG) have been developed and agreed by a multidisciplinary expert group (including medical and radiation oncologist, surgical oncologist, orthopaedic surgeons, radiologist, pathologist, molecular biologist and representatives of patients advocacy groups) of the SELNET consortium, and are conceived to provide the standard approach to diagnosis, treatment and follow-up of bone sarcoma patients in the Latin-American context.

Microstructured Nickel-Titanium Thin Film Leaflets for Hybrid Tissue Engineered Heart Valves Fabricated by Magnetron Sputter Deposition.

Heart valves are constantly exposed to high dynamic loading and are prone to degeneration. Therefore, it is a challenge to develop a durable heart valve substitute. A promising approach in heart valve engineering is the development of hybrid scaffolds which are composed of a mechanically strong inorganic mesh enclosed by valvular tissue. In order to engineer an efficient, durable and very thin heart valve for transcatheter implantations, we developed a fabrication process for microstructured heart valve leaflets made from a nickel-titanium (NiTi) thin film shape memory alloy. To examine the capability of microstructured NiTi thin film as a matrix scaffold for tissue engineered hybrid heart valves, leaflets were successfully seeded with smooth muscle cells (SMCs). In vitro pulsatile hydrodynamic testing of the NiTi thin film valve leaflets demonstrated that the SMC layer significantly improved the diastolic sufficiency of the microstructured leaflets, without affecting the systolic efficiency. Compared to an established porcine reference valve model, magnetron sputtered NiTi thin film material demonstrated its suitability for hybrid tissue engineered heart valves.

[Interventional mitral valve replacement. Current status]. / Interventioneller Ersatz der Mitralklappe. Aktueller Stand.

Approximately 30 % of patients suffering from severe valvular heart disease, such as mitral valve regurgitation are non-compliant to the gold standard of minimally invasive surgery, reconstruction or valve replacement. The number of these mostly old patients with severe comorbidities is increasing; therefore, transcatheter interventions have been developed to address an unmet clinical need and may be an alternative therapeutic option to the reference standard. Apart from the successful MitraClip therapy, alternative transcatheter reconstruction technologies are being developed. As with transcatheter aortic valve implantation (TAVI) procedures, the off-pump implantation of a valved stent into the mitral position mainly via a transapical approach will be of great benefit. Recently, the feasibility of transcatheter mitral valved stent implantation in high-risk patients has already been reported.

Resection of calcified aortic heart leaflets in vitro by Q-switched 2 µm microsecond laser radiation.

BACKGROUND: Transcatheter aortic valve implantation (TAVI) can result in paravalvular leakage and stent deformation in the presence of severe calcification. This study was undertaken to determine the efficacy of laser-assisted resection of calcific aortic valve leaflets as a method to minimize the effects of calcium on perivalvular leakage during TAVI. METHODS: A Q-switched Tm:YAG laser emitting at a wavelength of 2.01 µm was used to evaluate the cutting efficiency on highly calcified human aortic leaflets in vitro (N = 10). A pulse energy of 4.3 mJ, a pulse duration of 0.8-1 µs, and a repetition rate of 1 kHz were used. The radiation was transmitted via a 200 µm core diameter quartz fiber. Resection was performed in a fiber-tissue contact mode on water-covered samples in a dish. The remnant particles were analyzed with respect to quantity and size by light microscopy. RESULTS: A resection rate of 40.4 ± 22.2 mg/min on highly calcified aortic leaflets was achieved. This corresponds to a cutting speed of approximately 1 cm/min; a laser dissection time of 3 min per leaflet is expected. The majority of the remnant particles (85.4%) were <6 µm in diameter, with only 0.1% exceeding 300 µm. CONCLUSIONS: The Q-switched Tm:YAG laser system showed promising results in cutting calcified aortic valves, by transmitting sufficient energy through a small flexible fiber. Catheter-based removal of aortic valve calcification may help to improve TAVI technology.

Transapical mitral valve implantation: the Lutter valve.

  The development of transcatheter techniques for treatment of severe mitral valve regurgitation in the beating heart is focus of recent research. An off-pump treatment technique poses great benefits, particularly for multimorbid patients, often being non-compliant to the gold standard treatment, being open heart surgery with use of a cardiopulmonary bypass. Thereto, two approaches are being followed: transcatheter valve repair and transcatheterimplantation of a valved stent into the native mitral valve annulus. A valved stent has to provide safe and secure fixation within the high pressure system of the left heart. One of the main challenges in the development of such a valved stent is the complex anatomy of the mitral valve, with no clearly defined structures for device anchorage. Our group has developed a self-expanding nitinolvalved stent for transapical implantation in the beating heart. During the development process of thevalved stent, different design iterations were conducted to decrease the risk of paravalvular leakages, to enhance the reproducibility and to improve the overall stent performance. This article reviews the major milestones passedin the development process of our mitral valved stent and advances achieved withinthe last years. Multiple design iterations lead to a prototype providing secure stent deployment, hig h reproducibility, low paravalvular leakages and only mild stent deformation in the beating heart. In future, further long-term in vivo trials have to be conducted before attempting the step towards clinical application of this novel device.

Octogenarians undergoing combined aortic valve replacement and myocardial revascularization: perioperative mortality and medium-term survival.

OBJECTIVE: Aim of the study was to answer the question whether the mortality and morbidity of octogenarians undergoing combined aortic valve replacement and myocardial revascularization (AVR + CABG) is higher than that of younger patients. PATIENTS AND METHODS: Between 01/1995 and 12/2002, 242 patients underwent AVR + CABG in our institution. 37 patients were older than 80 years (16 male, 21 female, median pressure gradient over the aortic valve: 53 mmHg, median EF: 62%), 205 patients were younger than 80 years (133 male, 72 female, median gradient 48 mmHg, median EF: 61%). NYHA class, aortic valve area and valve calcification were worse in the 80+ group. Biological valve prostheses were implanted in 94.6% of the older and in 45.4% of the younger patients (p < 0.001). RESULTS: Perioperative complications occurred more often (p = 0.0188) in the 80+ group (86.5% experienced 1 or more complications) than in the 80- group (66.3%). Similarly, the MACE (Major Adverse Cardiovascular Events) rate was higher (p = 0.0448) in the 80+ group than in the 80- group. Bleeding occurred (p = 0.092) more often in younger (9.3%) than in older (0%) patients, while renal insufficiency was more frequent (p = 0.0164) in older (21.6%) than in younger patients (7.8 %). The 30-day mortality was higher (p = 0.0045) in older (21.6%) than in younger patients (5.8%). Multivariate analysis revealed an odds ratio for early death of 2.9 (CI 1.014-8.397) for patients older than 80 years. The late death rate within the first 5 years after surgery was comparable in both groups (80- group 24.4%, 80+ group 24.3%). Postoperative quality of life was significantly worse in the 80+ group in 4 out of 8 functions. CONCLUSIONS: Octogenarians undergoing AVR + CABG have a relatively high perioperative complication rate and mortality, but show a stable medium-term survival. The perioperative complication rate is higher in older than in younger patients, and the postoperative quality of life with regard to bodily functions is acceptable but significantly worse than that of younger patients.

Should the aortic valve be replaced in patients with mild aortic stenosis admitted for coronary surgery?

BACKGROUND: The question whether the aortic valve in patients with mild aortic stenosis undergoing coronary artery bypass grafting (CABG) should be replaced or left alone is still controversial. METHODS: Between 01/1995 and 03/2004, 38 patients (30 male, 8 female, mean age 70.9 +/- 7.8 years) required redo AVR 7.1 +/- 4.8 years after primary CABG, while 202 patients (125 male, 77 female, mean age 72.7 +/- 7.8 years) underwent combined AVR and CABG (1.9 +/- 0.8 grafts/patient). To evaluate the different approaches, the data of the redo-AVR group were compared with the data of a propensity-score matched group of AVR + CABG patients. RESULTS: All patients survived the procedure; the 30-day survival was 94.7 % in both groups. The 1- and 5-year survival rates were 94.7 % and 83.8 % in the AVR after CABG group, and 94.7 % and 86.9 % in the AVR + CABG group, respectively. The late mortality was 28.9 % in the AVR after CABG and 25 % in the AVR + CABG group. Statistically, significant differences regarding perioperative mortality and morbidity could not be detected, neither with nor without propensity score analysis. CONCLUSION: Combined AVR and CABG in patients with coronary artery disease and mild to moderate aortic stenosis seems advisable in an institution with an equally low perioperative risk for both procedures, because the patient will need only one surgical procedure instead of undergoing surgery with all the associated risks twice.

Is there really a clinical benefit of using minimized extracorporeal circulation for coronary artery bypass grafting?

BACKGROUND: Minimized extracorporeal circulation is intended to reduce the negative effects associated with cardiopulmonary bypass. This prospective study was performed to evaluate whether minimized extracorporeal circulation has a clinical benefit for coronary artery surgery patients compared to standard extracorporeal circulation. METHODS: Sixty patients were randomized into two study groups: 30 patients underwent coronary artery bypass grafting using minimized extracorporeal circulation and 30 patients were operated using standard extracorporeal circulation. Baseline characteristics, intraoperative details, postoperative data, perioperative blood chemistry determinations of hematocrit, platelets, muscle-brain fraction of the creatine kinase, cardiac troponin T and colloid osmotic pressure as measurements of intrathoracic blood volume index and extravascular lung water index were compared. RESULTS: Baseline characteristics and intraoperative details of both groups were similar. Patients who underwent minimized extracorporeal circulation showed more short-term dependency on norepinephrine ( P < 0.01). Their maximal postoperative muscle-brain fraction of the creatine kinase was lower ( P < 0.05) and their hematocrit on arrival in the intensive care unit was higher ( P < 0.01). No other significant differences were found. In both collectives, values for hematocrit ( P < 0.001), platelets ( P < 0.001), colloid osmotic pressure ( P < 0.001) and intrathoracic blood volume index ( P < 0.05) decreased, while the extravascular lung water index did not change significantly during cardiopulmonary bypass. CONCLUSIONS: A clinical advantage of minimized over standard extracorporeal circulation was not found. Furthermore, a higher number of patients in the minimized extracorporeal circulation group required postoperative norepinephrine infusions for hemodynamic stabilization. In summary, the presumed superiority of minimized extracorporeal circulation for coronary artery bypass grafting in standard patients could not be confirmed.

Prevention of device-related tissue damage during percutaneous deployment of tissue-engineered heart valves.

BACKGROUND: Endovascular application of pulmonary heart valves has been recently introduced clinically. A tissue-engineering approach was pursued to overcome the current limitations of bovine jugular vein valves (degeneration and limited longevity). However, deployment of the delicate tissue-engineered valves resulted in severe tissue damage. Therefore the objective of this study was to prevent tissue damage during the folding and deployment maneuver. MATERIAL AND METHODS: Porcine pulmonary heart valves, small intestinal submucosa, and ovine carotid arteries were obtained from a slaughterhouse. After dissection and antimicrobial incubation, the valves were trimmed (removal of sinus and most of the muscular ring) to fit into the deployment catheter. The inside (in-stent group, n = 6) or outside (out-stent group, n = 6) of a nitinol stent was covered by an acellular small intestinal submucosa, and the valves were sutured into the stent. The valves were folded, tested for placement in the deployment catheter, and decellularized enzymatically. Myofibroblasts were obtained from carotid artery segments and seeded onto the scaffolds. The seeded constructs were placed in a dynamic bioreactor system and cultured for 16 consecutive days. After endothelial cell seeding, the constructs were folded, deployed, and processed for histology and surface electron microscopy. RESULTS: The valves opened and closed competently throughout the entire dynamic culture. Surface electron microscopy revealed an almost completely preserved tissue in the in-stent group. Stents covered with small intestinal submucosa on the outside, however, showed severe damage. CONCLUSION: This study demonstrates that small intestinal submucosa covering of the inside of a pulmonary valved stent can prevent stent strut-related tissue damage.

[Arterial grafts in coronary surgery for diabetic patients]. / Koronare Revaskularisation bei Diabetikern--Stellenwert von arteriellen Grafts.

Surgical revascularization allows especially for the diabetic patient with coronary multi-vessel disease a superior long-termperspective compared to percutaneous coronary interventions. However, the specific advantages and also risks associated with the expanded use of arterial grafts as coronary conduits in diabetics are not clearly answered. A systemic analysis of the current literature underlines the following statements: The radial artery is, compared to the internal mammary artery, to a higher extent prone to atherosclerosis, especially in diabetic patients. Better long-term survival for patients with bilateral IMA-grafts has also been assessed for diabetic patients. The risk of thoracic wound infections is not obligatory increased for diabetics with double IMA-grafts. Revascularization with radial arteries can be performed with low perioperative risks. Long-term results or studies on radial artery bypass grafting especially in diabetics are not available. In our own experience (3,548 isolated coronary operations, 01/2001 until 05/2005), diabetic patients have no increased perioperative mortality, even when using more complex arterial grafting. Conclusively, diabetic patients should also significantly benefit from the use of the second mammary artery. Regarding conduit quality, a second IMA appears favorable over the radial artery.

Percutaneous valve replacement: weird or wonderful?

Percutaneous treatment of valve diseases has proven to be an effective alternative to open surgery since the early 1980's. For most patients with rheumatic mitral stenosis, use of percutaneous catheter-based techniques as balloon valvuloplasty for the treatment of both congenital pulmonary stenosis as well as trans-septal commissurotomy has become a good therapeutic option. Furthermore in the mid 1990's in vitro studies demonstrated the feasibility of percutaneous catheter-based valve implantation first in pulmonary and subsequently in aortic position. Afterwards initial in vivo implantations were successfully undertaken. Limitations of this new branch of transcatheter-based techniques are: risk of embolization due to pre-dilatation; difficult deployment; migration of valved stent; paravalvular leakage and limited durability of the implanted valve. Hence, many advances and improvements are necessary prior to pronouncing a new real alternative and safe therapeutic option. Up to now the gold standard for the treatment of heart valve disease is still open surgical valve repair and replacement. Percutaneous valve replacement procedures offer substantial advantages both to patients and medical care providers. From a medical point of view, they may help reduce surgical risks, offer a less invasive procedure, lower complication rates and shorten rehabilitation times in future. From an economic standpoint, shorter hospital stays result in overall cost reduction.

Biological bypass in cardiovascular surgery.

Protein and gene therapy offer a tremendous opportunity to improve the care of critically ill patients with ischemic heart and peripheral artery occlusion disease. With the availability of purified growth factors such as vascular endothelial and fibroblast growth factors (FGF), several experimental and clinical studies provided data, that the growth of capillaries (angiogenesis) and of collateral arteries (arteriogenesis) is not limited to its natural time course. When applied in experimental models and in conjunction with coronary artery bypass operations, FGF in particular, led to a significant increase in endogenous rerouting of blood flow by collateral vessels inside the tissue itself. Thus, the proliferation of preexisting bypassing arterioles could be enhanced therapeutically (biological bypass). The purpose of this review is to discuss the physiological importance of different kinds of cytokines which are able to induce angio- and arteriogenesis in ischemic limbs or the heart. It is outlined that a combination of a sufficient amount of large arterioles and a capillary network are needed to compensate perfusion deficits. Each patient, who has an ischemic area and cannot be conventionally revascularized, is a potential candidate for the biological bypass.

Viability of the myocardium after twenty-four-hour heart conservation--a preliminary study.

BACKGROUND: Orthotopic heart transplantation following ischemic times beyond four hours is associated with increased risk of early graft failure. The use of modern myocardial preservation strategies could enable safe transplantation after long-term conservation. In this study, we tested a new myocardial protection regime in an experimental model of 24 h storage. METHODS: Orthotopic heart transplantations (n=15) were performed in a pig model. Donor hearts were flushed with Bretschneider solution, excised, and stored for 24 hours at 4 degrees C. During implantation, controlled reperfusions with substrate-enriched leukocyte-depleted blood cardioplegia were performed after each anastomosis. Blood cardioplegia contained 1 mmol/l of the Na(+)-H(+)-exchange inhibitor HOE 642 and 100 mg/l of adenosine. Controlled reperfusion was continued with leukocyte-depleted blood for 20 min. A microaxial pump was inserted after heart transplantation and circulatory assistance was maintained for five hours to prevent right heart failure. RESULTS: No initial graft failure could be observed. Thirteen hearts could be weaned from extracorporeal circulation. Due to bleeding problems, kidney and lung failure only five hearts could be included in the final analysis. Hemodynamics of these hearts remained stable with epinephrine at 0.1 micro g/kg/min. Myocardial oxygen consumption 20 min after start of reperfusion (5.3+/-2.0 ml/100 g/min) did not differ significantly versus baseline (6.8+/-2.0 ml/100 g/min). Oxygen extraction six hours after heart transplantation was also well preserved compared to baseline (58.0+/-10.2 versus 49.2+/-8.8 %). Histological examination six hours after transplantation using luxol fast blue staining revealed that only 1.0 % of the myocytes were irreversibly damaged. CONCLUSIONS: The data indicate full viability of the myocardium after 24 h conservation. The preservation technique described could contribute to the extension of conservation times in heart transplantation and enable transplantation of marginal donor hearts.

Endoscopic vs. conventional vein harvesting: first results with a new, non-disposable system.

BACKGROUND: Most of the grafts used in coronary bypass surgery are still venous grafts. The preferred vein for bypass surgery is the long saphenous vein. Severe wound complications caused by saphenous vein harvesting occur in 1 % to 3 % of cases. Minor complications that do not need surgical revision occur in up to 43 % of cases. We developed an endoscopic harvesting technique using non-disposable instruments to reduce wound complications caused by vein harvesting. METHOD: In a retrospective study, the occurrence of wound complications, haematoma, postoperative pain, ambulation, sensory disturbances and patient satisfaction were studied (n = 182). Patients who had either endoscopically harvested (n = 91) or conventionally harvested (n = 91) saphenous vein grafts were reviewed. RESULTS: Results were collected for 173 patients. The overall prevalence of wound complications was 18.7 %. The incidence of wound healing complications could be reduced significantly (p = 0.015) from 15.3 % to 3.4 % using the endoscopic technique. In the endoscopic group, postoperative ambulation was significantly (p = 0.002) easier, patient satisfaction was significantly (p = 0.007) higher, and postoperative leg swelling (p = 0.003) and haematoma (p = 0.004) could be reduced significantly. The occurrence of postoperative pain and sensory disturbances did not differ significantly. COMMENT: We conclude that the used endoscopic vein harvesting is a safe and cost effective method that can significantly reduce wound complications. An ongoing prospective study should establish our demonstrated data.

Microperfusion enhancement after TMLR in chronically ischemic porcine hearts.

OBJECTIVE: The purpose of this study was to determine the effect of transmyocardial laser revascularization (TMLR) on myocardial perfusion and function in chronically ischemic myocardium. METHODS: In the first operation a stenosis of the left anterior descending artery was created in 20 open-chest anesthetized pigs to implement this ischemic model. In contrast, four pigs served as controls (thoracotomy only). Seven days later (2nd operation), all animals were studied at baseline by analyzing different parameters of perfusion (radioactive microspheres), function, and intramyocardial pressure. Afterwards, pigs who received a left anterior descending artery stenosis were randomized into one of three groups: animals in laser group 1 (n=7) received one and in laser group 2 (n=7) two laser channels per cm(2) in the left anterior descending artery territory. Animals of the ischemic group (n=6) underwent the same procedures without transmyocardial laser revascularization. Three months later, the animals were re-studied (3rd operation) and additional analysis of histochemistry and myocardial water content was performed. RESULTS: Regional myocardial blood flow (RMBF) in laser group 2 revealed statistically higher RMBF values compared to the ischemic group (0.39+/-0.13 versus 0.14+/-0.12 ml/min/g; P=0.043), after 3 months, whereas the absolute RMBF had not increased compared to the 1-week baseline values. Left ventricular stroke work index (LVSWI) at rest and under stress did not show any improvement compared to the initial values in all study groups (P=ns). Nevertheless, laser group 1 demonstrated relatively higher LVSWI(max) values compared to the ischemic (1.33+/-0.19 versus 0.93+/-0.16 mJ/kg; P=0.03) and laser group 2 (1.33+/-0.19 versus 1.02+/-0.15; P=0.024). Regional contractility of laser groups 1 and 2 recovered after 3 months (which had deteriorated shortly after transmyocardial laser revascularization) and increased under stress (100% versus 144.33+/-46.42, P=0.029 and 100% versus 116.26+/-21.06, P=0.034; respectively). In contrast, the corresponding ischemic group values were not different from initial values (P=ns). CONCLUSIONS: This model of chronic regional ischemia demonstrates that CO(2)-laser revascularization significantly improves microperfusion and regional function, whereas the overall perfusion and global LV function is unchanged.

Investigations on the new free radical scavenger polynitroxyl-albumin to prevent ischemia and reperfusion injury after orthotopic heart transplantation in the pig model.

OBJECTIVE: Nitroxides have strong antioxidant capacity but their effectiveness is limited by their rapid intracellular inactivation. Polynitroxyl-Albumin (PNA) is capable of regenerating inactivated nitroxide. We tested the effect of PNA against reperfusion injury in heart transplantation. METHODS: Pig hearts were transplanted orthotopically. In the control group (n=9) reperfusion was performed without reperfusion modifications. In the experimental group (n=10) 1 ml/kg PNA was given before cross-clamp release. RESULTS: Hemodynamic performance was impaired after transplantation in both groups without significant intergroup differences. Plasma malonedialdehyde levels were significantly diminished in the PNA group as compared to the controls. CK-MB levels in both groups were increased within the first 2 h of reperfusion without significant intergroup differences. In contrast, there were found significant higher values of myocardial specific lactate dehydrogenase (LD1) in the controls versus PNA group. CONCLUSIONS: PNA was able to reduce lipid peroxidation and attenuate free radical activity. Contractile dysfunction could no be improved, indicating that (a) the radical scavenging effect was to weak or (b) other mechanisms than free oxygen radicals are responsible for myocardial damage in this experimental model.