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Biomedical subjects

G Lutter

Publications and source records attributed to G Lutter.

At least 19 recordsLinked to original sources

[Arterial grafts in coronary surgery for diabetic patients].

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.

Angioplasty, Balloon, Coronary↗

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.

Animals↗

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.

Animals↗

First results of the search for neutrinoless double-beta decay with the NEMO 3 detector.

The NEMO 3 detector, which has been operating in the Fréjus underground laboratory since February 2003, is devoted to the search for neutrinoless double-beta decay (beta beta 0v). The half-lives of the two neutrino double-beta decay (beta beta 2v) have been measured for 100Mo and 82Se. After 389 effective days of data collection from February 2003 until September 2004 (phase I), no evidence for neutrinoless double-beta decay was found from approximately 7 kg of 100Mo and approximately 1 kg of 82Se. The corresponding limits are T1/2(beta beta0v) > 4.6 x 10(23) yr for 100Mo and T1/2(beta beta 0v) > 1.0 x 10(23) yr for 82Se (90% C.L.). Depending on the nuclear matrix element calculation, the limits for the effective Majorana neutrino mass are < 0.7-2.8 e/v for 100Mo and < 1.7-4.9 eV for 82Se.

Journal Article↗

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.

Angiopoietins↗

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.

Animals↗

Improved 3-D-echocardiographic endocardial border delineation using the contrast agent FS069 (Optison) transesophageal studies in a porcine model.

3-D echocardiography has the potential for quantitative assessment of regional wall motion. However, the 3-D procedures used to date do not provide the same spatial and temporal resolution as 2-D echocardiography, which results in problems with border delineation of the endocardium. There are, as yet, few studies testing if the use of contrast agent can improve endocardial definition in the 3-D data set. FS069 (Optison) was used for the first time for this purpose in the present study. A total of 12 mechanically-ventilated pigs were examined by transesophageal 3-D echocardiography, 1. using fundamental imaging and 2. following left-atrial injection of FS069 (Optison). The left ventricle was analyzed using an 18-segment model. Score with the value 0 (not visible), 1 (moderately visible) and 2 (well defined) were used to rate endocardial definition. All segments were assessed both end-diastolic and end-systolic. Various LV regions were examined by grouping segments (anterior/lateral/inferior and basal/mid-ventricular/apical). Using the contrast agent, the proportion of nonvisible segments fell diastolic from 40 (18.5%) to 15 (6.9%), and systolic from 26 (12.0%) to 11 (5.1%). The proportion of well defined segments increased diastolic from 62 (28.7%) to 108 (50%) and systolic from 73 (33.8%) to 123 (56.9%). The mean visibility score increased diastolic from 1.10 +/- 0.68 to 1.43 +/- 0.62 (p < 0.001), systolic from 1.22 +/- 0.64 to 1.52 +/- 0.59 (p < 0.001). The benefit was greatest in regions where the visibility score was lowest without contrast: in the area of the lateral wall and systolic near the apex. In conclusion, the use of FS069 (Optison) results in significantly better endocardial delineation in the 3-D data set. This could be important in future for the 3-D echocardiographic assessment of regional wall motion.

Albumins↗

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.

Angioplasty, Laser↗

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.

Albumins↗

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.

Aged↗

[Bleeding problems in open heart surgery].

Across centers, transfusion can vary eightfold for the same mediastinal drainage after adult cardiac operations. Excessive blood drainage resulting in increased transfusions occurs in 29% of patients. Various strategies have been proposed to decrease bleeding and allogenic transfusion requirements in the perioperative period of heart surgery. Blood conservation methods were reviewed critically. Avoidance of preoperative anemia, tolerance of low hemoglobin concentrations, the use of autologous blood, and adherence to a strict transfusion protocol will reduce the use of allogenic transfusions. Perioperatively, maintenance of normothermia contributes to improved hemostasis.

Adult↗

Evaluation of the indirect revascularization method after 3 months chronic myocardial ischemia.

OBJECTIVE: The long-term effectiveness of transmyocardial laser revascularization (TMLR) was evaluated in the setting of a severe left anterior descending artery (LAD) stenosis. METHODS: To employ the chronic ischemic model, pigs underwent three operative procedures over a 13-week period. In the first operation, an operative stenosis of the LAD was created. One week later, the animals were studied at baseline by analyzing different parameters of perfusion (microspheres), function and ECG changes. Afterwards, pigs were randomized into one of three different experimental groups: animals in laser group 1 received one laser channel (n=9) and laser group 2 two channels per cm(2) (n=6) in the LAD territory (using a CO(2)-laser). Animals of the ischemic group (n=12) underwent the same procedures without TMLR-treatment. Twelve weeks later, the animals were re-studied (third operation) and killed. Additional analysis of myocardial water content and histochemistry was performed. RESULTS: Chronic myocardial ischemia and regional myocardial blood flow (RMBF) in laser group 2 revealed relatively higher RMBF values compared with the ischemic group (P=0.015), after 3 months, but no absolute improvement of perfusion at rest compared with baseline was observed in all experimental groups. Left ventricular stroke work index (LVSWI) at rest and under stress did not show any improvement compared with initial values in all study groups (P not significant). However, laser group 1 demonstrated relatively higher LVSWI(max) values in comparison with the ischemic group (P=0.013) as did laser group 2 (P=0.017). Regional contractility of the laser groups recovered after 3 months (which was deteriorated shortly after TMLR, P<0.001) and increased under stress compared with baseline (laser 1: P=0.015, laser 2: P=0.017). In contrast, the ischemic group did not show any difference from initial values (P not significant). The lased pigs of group 2 were less prone to intractable ventricular fibrillation (P=0.036 vs. ischemic group), and showed a significant smaller area of necrosis in the area at risk (P=0.012 vs. ischemic group). CONCLUSIONS: This model of chronic regional ischemia demonstrates that CO(2)-laser revascularization significantly ameliorates microperfusion and regional contractility, and diminishes the incidence of ventricular fibrillation and necrosis in the area at risk. However, it does not change the overall perfusion and global LV function.

Animals↗

Pathomorphological and histological analysis of the indirect revascularization method.

OBJECTIVE: This experimental study was initiated to determine whether TMLR may prevent porcine myocardium from ischemia and necrosis after acute myocardial infarction. In addition, the influence of TMLR on healthy myocardium was analyzed. METHODS: The short-term effectiveness of TMLR was evaluated in 38 open-chest anesthetized pigs with (n = 18) or without (n = 20) acute LAD occlusion (observation period 6 hours): Six pigs served as controls (thoracotomy only). An additional six pigs had LAD occlusion only (ischemic group). A subsequent 12 pigs were treated by TMLR (CO2) prior to LAD occlusion: Six pigs received one laser channel/cm2 (group 1) and in six pigs two channels/cm2 in the LAD territory (group 2) were performed. In addition, 14 pigs underwent TMLR without ischemia: Seven pigs received 1 channel/cm2 (group 3) and seven pigs 2 channels/cm2 (group 4). Pathomorphological assessment and histology were performed. RESULTS: TMLR limits the expansion of the myocardial infarction zone: laser group 2 demonstrated a significantly smaller area of necrosis in the area at risk (ischemic group (32%) vs. laser group 1 (18%, p = ns) and 2 (8%, p = 0.0076); laser group 1 vs. 2, p = 0.0056). The amount of the area of necrosis of laser groups 3 (0.4%) and 4 (0.04%) compared to control (0%) did not differ significantly (p = ns). Furthermore, in the lased territories of laser groups 3 and 4 microscopic analysis revealed signs of ischemia in 10 +/- 30.9% of all examined histological samples (p = ns vs. control). During a short coronary occlusion the laser-induced tracks were partially filled with blue dye in 94.8 +/- 27.0/85.9 +/- 34.3/94.85 +/- 22.0%/70.21 +/- 47.0% (laser groups 1 - 4 respectively p = ns) The myocardial water content-measurements (MWC) of the ischemia and laser group 1 were not different at the end of the experiment (p = ns). In contrast, laser groups 2, 3 and 4 revealed significantly higher MWC values compared to control (p = 0.036, p < 0.001, p < 0.001; respectively). CONCLUSIONS: This prolonged acute study demonstrates that preventive CO2-laser revascularization significantly reduces the amount of necrosis in the area at risk. Histological examination supported the idea that some pigment gained access to the ischemic tissue via patent channels. In healthy myocardium, TMLR significantly increases myocardial water content and induces non-significant small ischemic and very small necrotic areas surrounding open laser channels.

Animals↗

Evaluation of transmyocardial laser revascularization by following objective parameters of perfusion and ventricular function.

BACKGROUND: Does transmyocardial laser revascularization (TMLR), a new surgical technique for treating patients with otherwise intractable angina pectoris, improve myocardial perfusion, metabolism, and, consequently, function? METHODS: Patients referred for TMLR, alone or with coronary artery bypass grafting (CABG), were preoperatively evaluated clinically and by treadmill stress testing, echocardiography, ventriculography, radionuclide assessment of perfusion and metabolism, and hemodynamic assessment. Intraoperatively it was decided that some patients only required CABG. Follow-up evaluations were repeated after 6 (n = 40) and 12 months (n = 23) and compared with preoperative values. RESULTS: CABG only was performed in 35 cases, TMLR + CABG in 17, TMLR only in 45. 1-year mortality was 11% in the TMLR, zero in the TMLR + CABG, and 11% in the CABG groups. In all groups a significantly improved CCS angina- and NYHA class was observed immediately after operation and after 6 and 12 months. In all study groups treadmill tolerance (p<0.05) improved, but regional and global function, perfusion at rest, and metabolism were not significantly changed at 6 and 12-months follow-ups. Perfusion studies under stress demonstrated an improvement only in the CABG group after 12 months (p<0.05), whereas in both TMLR groups the lasered ischemic segments remained unchanged. CONCLUSIONS: TMLR significantly improves long-term clinical status and treadmill stress tolerance, but appears to have little if any effect upon regional and global function, perfusion, and metabolism.

Aged↗

Transmyocardial laser revascularization: experimental studies in healthy porcine myocardium.

BACKGROUND: Clinical studies have demonstrated a significant reduction of cardiac index shortly after transmyocardial laser revascularization in patients with low ejection fraction. We analyzed the influence of transmyocardial laser revascularization on healthy myocardium in pigs. METHODS: Carbon dioxide channels were created in 20 pigs which were observed for 6 hours. Ten pigs received one laser channel and ten pigs two laser channels per cm2 in the left anterior descending artery region. Seven pigs served as controls. Perfusion (microspheres), function, histochemical, and histologic assessments were subsequently performed. RESULTS: A significant deterioration of left ventricular stroke work index was observed shortly after transmyocardial laser revascularization in both laser groups (p < 0.05). After 6 hours the left ventricular stroke work index did not increase and showed significantly reduced values at rest (p < 0.05) and during stress in the laser groups (p < 0.01). Normal regional perfusion, small ischemic and necrotic areas, open laser channels in the left anterior descending artery region and significantly increased myocardial water content were observed in the laser groups (p < 0.01). CONCLUSIONS: Carbon dioxide laser channels significantly decrease global heart function shortly after transmyocardial laser revascularization in healthy porcine myocardium. This myocardial tissue showed no recovery 6 hours postoperatively.

Animals↗

Analysis of the new indirect revascularization method by determining objective parameters of clinical chemistry, histo-chemistry and histology.

OBJECTIVE: This experimental study was initiated to determine whether transmyocardial laser revascularization (TMLR) after acute myocardial ischemia may improve clinical chemistry and diminish the amount of necrosis. In addition, the influence of TMLR on healthy myocardium was analyzed. METHODS: The prolonged short-term effectiveness of TMLR was evaluated in 44 open-chest anesthetized pigs with (n = 21) or without (n = 23) the setting of acute myocardial ischemia (observation period 6 h): seven pigs served as controls (thoracotomy only). An additional seven pigs had left anterior descending artery (LAD) occlusion only (ischemia group). A subsequent 14 pigs were treated by TMLR (CO2) prior to LAD occlusion: Seven pigs received one laser channel/cm2 (group 1) and in seven pigs two channels/cm2 in the LAD territory (group 2) were performed. In addition, 16 pigs underwent TMLR without ischemia: Eight pigs received one channel/cm2 (group 3) and eight pigs two channels/cm2 (group 4). Clinical chemistry, histo-chemical assessment and histology were performed. RESULTS: TMLR limits the expansion of the myocardial infarction zone: laser group 2 indicated a significant smaller area of necrosis in the area at risk (ischemic group (31%) vs. laser group 1 (19%), P = ns; laser group 2 (7%) vs. ischemic group, P < 0.01; laser group 1 vs. 2, P < 0.01). The amount of the area of necrosis and ischemia of laser groups 3 and 4 compared with control did not differ significantly (P = ns). Preventive creation of microchannels before ischemia did not diminish ischemic parameters (P = ns). The myocardial water content-measurements (MWC) in the ischemia, laser 1 and 2 groups did not show any difference at the end of the experiment, except higher values of laser group 2 (P < 0.05). Laser groups 3 and 4 revealed significantly higher MWC values compared with control (P < 0.001). CONCLUSIONS: This prolonged acute study demonstrates that CO2-TMLR significantly reduces the amount of necrosis in the area at risk, but does not reduce cardiac ischemic markers. In healthy myocardium, TMLR significantly increases myocardial water content and ischemic parameters and induces small ischemic and very small necrotic areas surrounding open laser channels. Generally, the elevated cardiac enzymes and proteins are mainly attributed to the expected rise caused by vaporization of myocardial tissue in all laser groups.

Analysis of Variance↗