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Biomedical subjects

L Eckel

Publications and source records attributed to L Eckel.

At least 37 records · Page 2Linked to original sources
PubMed1994

[An isolated tuberculoma in the left ventricle].

In the course of 8 weeks, a 62-year-old woman with chronic bronchitis developed increasing dyspnoea on effort and reduced well-being. The chest radiograph revealed a round focus, 2 x 3 cm, in the region of the left ventricle which, from the results of echocardiography and left-heart catheterization, suggested myxoma. At open-heart surgery under extracorporeal circulation an encapsulated tumour was found on the mural leaflet of the mitral valve, directly caudal of the atrioventricular plane. On opening, the capsule contained dough- or paste-like, yellowish-white substance with scattered polygonal granules, typical of a tuberculoma. The entire contents and capsule were excised. Immediately after operation tuberculostatic treatment was initiated (three times daily ethambutol, 400 mg, and once daily rifampicin, 600 mg, and isoniazid, 300 mg), even though acid-fast rods were not demonstrated histologically and by culture. Polymerase chain reaction, however, established the presence of Mycobacterium tuberculosis in the resected material. There was no evidence of florid tuberculosis in the subsequent course.

Cardiomyopathies↗
PubMed1994

Immediate postoperative recovery of regional wall motion after unilateral and bilateral internal mammary artery revascularization.

Within the last few years the importance of the internal mammary artery (IMA) for coronary revascularization has increased rapidly. Although there is no doubt about the superior long-term patency of this artery in comparison to saphenous vein grafts, the discussion about early postoperative results is controversial. The aim of the present study was to assess segmental wall motion after unilateral and bilateral IMA revascularization. Thirty-three patients who underwent elective myocardial revascularization were examined. In addition to vein grafts, bilateral IMA grafts were used in 8 patients and unilateral ones in 25 patients. Myocardial segmental wall motion was assessed by transesophageal echocardiography perioperatively. Myocardial protection was achieved by standard cold blood cardioplegia. Global left ventricular function remained unchanged postoperatively (4 h) in both groups (unilateral IMA: 52.8% +/- 7.1% vs 49.8% +/- 11.1%; bilateral IMA; 47.7% +/- 8.7% vs 48.7% +/- 7.7%, ns). Anterior wall motion (left IMA grafts to left anterior descending artery (LAD) was decreased early postoperatively (30 min) in both groups (unilateral IMA: 50.9% +/- 15.3% vs 37.8% +/- 14.5%; bilateral IMA: 47.3% +/- 20.1% vs 30.4% +/- 8.5%, P < 0.05). Posterior wall motion was decreased in the bilateral IMA group (right IMA to right coronary artery (RCA), 47.8% +/- 7.2% vs 28.0% +/- 8.9%, P < 0.05) and remained unchanged in the unilateral IMA patients (vein grafts to RCA, 39.5% +/- 9.9% vs 41.4% +/- 17.5%, ns). Internal mammary artery revascularization may result in deterioration of segmental myocardial function in the early (< 4 h) postoperative period. Bilateral IMA grafts should therefore be used with caution in patients with impaired ventricular function.

Aged↗
PubMed1993

Left main coronary artery stenosis after aortic valve replacement: genetic disposition for accelerated arteriosclerosis after injury of the intact human coronary artery?

BACKGROUND: Left main coronary artery stenosis is a rare but life-threatening complication after aortic valve replacement because of coronary perfusion-related trauma to the vessel wall with cannulation of the coronary ostia. We investigated whether this complication still occurs in the 1990s despite the use of more advanced catheter materials and modern surgical preservation techniques. METHODS: Four years after identification of the first two cases in 1987, five further patients had developed left main coronary artery stenosis after aortic valve replacement (incidence, 0.9%) at the cardiothoracic clinic of the J.W. Goethe University and were studied for contributing factors. RESULTS: Severe coronary ostial stenosis developed within 1 to 6 months after aortic valve replacement. In one such case, intimal proliferation was seen in a biopsy specimen that was comparable to the restenosis induced by coronary angioplasty. The clinical characteristics of the patients developing the complication, the surgical technique, and the intraoperative course did not differ from the other patients. However, five of the seven patients (71%) had a common genetic trait concerning their apolipoprotein E genotype (the epsilon 4 allele) that is normally present in only 10% to 15% of patients screened (P < 0.01). CONCLUSIONS: These lesions seem to result from a uniform response of the vessel wall to injury. Their incidence is probably related in part to the degree of injury after trauma to the coronary ostia during cannulation for myocardial protection. Patients with the epsilon 4 allele might be genetically predisposed for a pathologically increased response of proliferative repair mechanisms after arterial injury. The complication can be avoided by not instrumenting the coronary ostia for direct antegrade cardioplegia but using retrograde delivery as an alternative method of myocardial protection.

Adult↗
PubMed1993

Studies of reperfusion injury in skeletal muscle: controlled limb reperfusion to reduce post-ischaemic syndrome.

Revascularization after prolonged complete limb ischaemia may result in both severe damage to skeletal muscle and various systemic manifestations of the postischaemic syndrome. Previous experimental studies performed by the authors have shown that these are caused, to a large extent, by normal reperfusion at normal systemic pressure and that this additional injury can be substantially reduced by controlled reperfusion of the revascularized limb before restoration of the normal circulation. This treatment includes control of the conditions of reperfusion and composition of the initial reperfusate. In the present study, this concept of controlled limb reperfusion was applied to patients with prolonged severe lower limb ischaemia. Controlled limb reperfusion was used in 11 patients after prolonged complete unilateral or bilateral ischaemia. The ischaemic interval ranged from 5 to 21 h. Two patients were in cardiogenic shock, ten had a history of associated cardiac disease and seven coexistent peripheral vascular disease. After systemic heparinization, thromboembolectomy was undertaken using a Fogarty catheter. Cannulas were placed in the iliac, profunda and superficial femoral arteries and connected to a reperfusion set. Oxygenated blood was drawn from the iliac artery and mixed with an asanguineous solution (ratio 6:1). This controlled reperfusate was returned to the profunda and superficial femoral arteries using a single roller pump. The system allows control of both the composition of the reperfusate (Ca2+, pH, osmolarity, glucose, substrate, PO2, free radical scavengers) and the conditions of reperfusion (pressure, flow, temperature). After 30 min of controlled limb reperfusion, the cannulas were removed, the arteriotomy closed and normal blood reperfusion started.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1993

Changing patterns of patients undergoing emergency surgical revascularization for acute coronary occlusion. Importance of myocardial protection techniques.

Between 1977 and 1992 a total of 163 consecutive patients underwent emergency coronary artery bypass grafting after acute coronary occlusion (94% after failed angioplasty). Patients were divided into four groups according to the method used for myocardial protection. The crystalloid cardioplegia group included 30 patients operated on from 1977 to 1980; the hypothermic fibrillation group included 60 patients (1980 to 1986); the blood cardioplegia group included 36 patients (1986 to 1989); and the blood cardioplegia with controlled reperfusion group included 37 patients (1989 to 1992). Preoperative data, ischemic time interval, collateral blood flow, intraoperative data, regional wall motion, global ejection fraction, myocardial infarct-specific electrocardiographic changes, enzyme release, rhythm disturbances, mortality, prevalence of intraaortic balloon pumping, and inotropic support were assessed in this retrospective study. Our data indicate that the current spectrum of patients undergoing emergency coronary artery bypass grafting after acute coronary occlusion are at a significantly higher risk compared with those 15 years ago, that is, increase in age (53 +/- 1 versus 59 +/- 2 years; p < 0.05), three-vessel disease (38% versus 3%; p = 0.004), acute occlusion of the left main coronary artery (11% versus 0%; p = 0.02), preoperative cardiogenic shock (35% versus 3%; p = 0.007), prevalence of acute two-vessel occlusion (22% versus 3%; p = 0.05), prevalence of previous infarction (59% versus 23%; p = 0.04), and duration of ischemia (3.0 +/- 0.2 versus 4.1 +/- 0.3 hours; p < 0.05). Despite the increase in patients with severely compromised ventricular function during recent years, the overall hospital mortality decreased to 5% (2/37) when maximal protection of the ischemic and remote myocardium was performed (preoperative intraaortic balloon pump, combined antegrade/retrograde substrate-enriched blood cardioplegia, warm induction, controlled reperfusion, prolonged vented bypass). Single-vessel disease was always associated with a low mortality, whereas mortality could be reduced with controlled blood cardioplegia in patients with multivessel disease (6%) and cardiogenic shock (15%). The immediate return of regional contractility in the previously ischemic area after controlled reperfusion might serve as an explanation for these favorable results. After unmodified blood reperfusion, normokinesis or slight hypokinesis occurs in only 34% to 46% in the early postoperative period (1 to 4 weeks) in comparison with 86% after controlled blood cardioplegia reperfusion (p < 0.05). We conclude that there is a significant increase in risk factors in patients undergoing emergency coronary artery bypass grafting and that improved methods of intraoperative myocardial protection are needed for these compromised patients.

Acute Disease↗
PubMed1993

[Surgical revascularization in patients with acute myocardial infarction].

This retrospective study was done to assess the results of emergency revascularization in patients with acute myocardial infarction. In addition, the influence of the mode of reperfusion was investigated in terms of morbidity and mortality. Between January 1987 and May 1992, 75 consecutive patients with acute coronary occlusion (in 87% PTCA-failure) received one of two different reperfusion protocols during emergency aortocoronary bypass operation. In 36 patients, the reperfusate was normal blood given at systemic pressure (uncontrolled reperfusion); in 39 patients, the ischemic area was initially reperfused for 20 minutes with a blood cardioplegic solution (substrate-enriched, hyperosmolar, hypocalcemic, alkalotic, diltiazem-enriched) given at 37 degrees C and at a perfusion pressure of 50 mmHg. Thereafter, the heart was kept in the beating empty state for 30 minutes before extra-corporeal circulation was discontinued (controlled reperfusion). Regional contractility (echocardiography, radionuclide ventriculography), electrocardiogram (ECG), release of creatine kinase and MB-isoenzyme of creatine kinase as well as hospital mortality were assessed. Quantification of regional contractility was done with a scoring system from 0 (normokinesis) to 4 (dyskinesis). Data are expressed as mean +/- standard error of the mean (SEM). Both groups were well matched for age, sex, and the distribution of the occluded artery. In the controlled reperfusion group, there was a higher incidence of additional significant stenosis (2.2 +/- 0.1 vs 1.7 +/- 0.1) and cardiogenic shock (36% vs 17%). Furthermore, the interval between coronary occlusion and reperfusion was longer in the controlled reperfusion group (4.1 +/- 0.3 vs 3.3 +/- 0.3 hrs; p > 0.05). Regional contractility returned to normal after controlled reperfusion (score 0.8 +/- 0.2; normokinesis = 0, slight hypokinesis = 1). In contrast, regional contractility remained depressed severely after uncontrolled reperfusion with normal blood (score 1.5 +/- 0.3; p < 0.05). Enzyme release and ECG-changes were similar in both groups postoperatively. While only 2 of 39 patients died in the controlled reperfusion group (5.1%), mortality increased to 11.1% (4/36) if normal blood is used as the primary reperfusate. Our data show, that the surgical revascularization during acute myocardial infarction can be performed with acceptable mortality and morbidity rates. Further improvement of the results can be obtained if controlled regional reperfusion for the previously ischemic area is used.

Angioplasty, Balloon, Coronary↗
PubMed1992

[Surgery of infiltrating tumors of the pericardium and myocardium].

Tumors arising from different organs may infiltrate the peri- and myocardium. Complete resections and defect repairs are possible using a variety of operating techniques. Although longterm survival rates of those patients with advanced tumor stages are unfavorable, individuals can be cured. Almost always, the patient's condition can symptomatically be improved by reduction of cardiac tamponade, venous congestion, and dyspnoe.

Cardiac Tamponade↗
PubMed1991

Quantitative analysis of protein deposits on hydrophilic soft contact lenses: I. Comparison to visual methods of analysis. II. Deposit variation among FDA lens material groups.

Patient-worn lenses (N = 1058) were evaluated using both the Rudko method for deposit typing and a quantitative assay for adsorbed protein. The visible deposit typing results were compared to the values obtained by the quantitative assay. The Rudko method for deposit classification was found to be a poor quantitative measure of deposited protein. Statistical differences were found between protein levels on lenses with identical Rudko scores among the FDA lens groups. In many cases, no meaningful correlation was found between Rudko scores and protein levels for lenses within the same FDA lens group. Significant differences in the distribution of visible deposits (Rudko scores) were found among the four FDA lens groups. Significant differences were also found in the quantity of adsorbed protein among FDA lens groups.

Contact Lenses, Hydrophilic↗
PubMed1991

[The vein as a transplant: aortocoronary and peripheral venous bypass].

Femoropopliteal bypass with below-the-knee anastomosis and the use of an autogenous saphenous vein yields the best results in longtime patency rate compared to the use of other graft materials. With anastomosis above the knee equally good results are also found with other graft materials. However, the late results show that even the saphenous vein is no perfect vessel substitute. Therefore, the indication for operation should be selected mainly for limb salvage and rest pain in stages III and IV, and the saphenous vein should be preserved for below-the-knee anastomosis. The greater saphenous vein for aorto-coronary bypass surgery is available in sufficient quantity, harvesting is quick and easy, and grafting can be done without great difficulty. The early results are good; the late patency rate again shows that the vein is no perfect vessel substitute and the results are inferior to those of the arteria mammaria grafts. The saphenous vein is the standard graft for aortocoronary bypass surgery and the graft of choice for emergency revascularization. The arteria mammaria graft to the left anterior descending is the better alternative. However, bilateral and complex mammary artery bypass grafting is only justified with comparable low operative mortality and morbidity. Because of the grafts disease the recommended norms for the surgical treatment of the coronary artery disease should include the use of the internal mammary artery on one hand, and appropriate early interventions for risk factors, including drug therapy, on the other hand. Prophylactic angioplasty of main-stem stenosis for the protection of functioning bypasses should also be considered.

Arteriosclerosis↗
PubMed1991

[Main branch stenosis following aortic valve replacement].

Three patients developed left main stem stenosis within some months after aortic valve replacement. In all of them diagnosis was confirmed by angiography and bypass surgery was performed successfully. Left main stem stenosis is a rare complication of aortic valve replacement and is due to cannulation and perfusion of the coronary arteries. The mechanism is probably injury of the vessel wall due to the perfusion-catheter, followed by intimal hyperplasia. A similar mechanism is assumed for restenosis after transluminal coronary angioplasty.

Adult↗
PubMed1990

Prolonged abnormalities of LV regional wall motion after normal reperfusion in patients with preoperative cardiogenic shock.

The purpose of this clinical study was to (1) evaluate mortality rates after surgical interventions for patients in cardiogenic shock (CS) secondary to acute coronary occlusion, acute ventricular septal defect (VSD) or acute valvular heart disease, (2) determine the pre-operative regional wall motion, and (3) ascertain the recovery of preoperative regional wall motion abnormalities after surgical intervention. The hospital records of twenty-five consecutive patients in CS were reviewed retrospectively. Regional wall motion was assessed preoperatively by ventriculography and postoperatively by 2D echocardiography (Sonotron Kardio VUE 60) after 1 and 3 days and at the day of discharge from the surgical ward (7-10 days). The left ventricle was divided in three segments according to the blood supply: LAD artery (antero-lateral wall), circumflex artery (lateral wall), and right coronary artery (inferior and basal wall). Regional wall motion was analyzed with the use of a scoring system in which grading was from 0 to 4 according to the following criteria: 0 = hyperkinesia, 1 = normokinesia, 2 = hypokinesia, 3 = dyskinesia, 4 = akinesia. Postmortem examination was performed in 8/9 patients. Data are presented as mean +/- SD. Significant differences were defined as probabilities for each test of p less than 0.05. The hospital mortality was higher for patients with acute coronary occlusion as compared to those with acute valvular disease or VSD (54.5%, 27.3%, 0%, resp.). The cause of death was cardiac in 7/9 patients. However, postmortem examination revealed loss by infarction of only moderate quantities of myocardium which could not explain the severe postoperative heart failure in those patients. Previous myocardial infarctions and preoperative cardiac arrest were significant risk factors for hospital mortality. In all patients with acute coronary occlusion (11/11) at least one region of the left ventricle was either a- or dyskinetic in the region supplied by the acute occluded vessel. In addition five patients had akinetic regions due to previous infarctions. The remaining remote myocardium was hypocontractile due to significant stenosis in coronary arteries supplying remote areas. Of 10 dyskinetic segments before surgical intervention, 5 were akinetic postoperatively, and only 5 developed slight hypokinetic contractions. The overall hypokinetic regions were not different as compared to the preoperative data (36.4% vs 39.4%). The normokinetic segments increased from 9.1% to 33.% (p less than 0.05).

Coronary Disease↗
PubMed1990

Adequate flow through the internal mammary artery graft achieved by a dilatation technique.

From Jan. 1984 to Dec. 1988 941 patients had internal mammary artery grafting alone or with vein grafts. There were 1705 associated vein grafts and 957 internal mammary grafts, for a total of 2 662 grafts (2.8 per patient). Use of the internal mammary artery was indicated in patients younger than 70 years with a significant stenosis of the main stem or the proximal left anterior descending artery in elective operations. The overall operative mortality was 3.4%, 2.9% for men and 6.2% for women. It rose to 9.6% in patients who were in New York Heart Association Class IV. Incidence of bleeding requiring reexploration was 5.5% and an intra-aortic balloon pump was implanted in 3% because of low cardiac output. At cardiac recatheterization (on average after 12 months) 88.3% of the internal mammary grafts and 63.3% of the vein grafts were patent. In investigation of, reasons for operative mortality, measuring the free flow of the internal mammary artery showed flow rates of 32-208 ml/min only slightly depending on the blood pressure. A technique of dilatation is described that significantly increases the flow rate up to 85%. The technique has been used regularly since Nov. 1987: from that date the IMA is only used if it has a flow rate of at least 60 ml/min.

Coronary Circulation↗
PubMed1990

[Thoracic aneurysms: criteria for surgical indications and results].

Elective operations of chronic thoracic aortic aneurysms (TAA) can be performed with low risk. In contrast, emergency repair of TAA in symptomatic patients including those with rupture is associated with a high mortality. The worst results were obtained (a) in patients who were in shock preoperatively, (b) with palliative procedures during acute dissection and (c) in patients older than 70. The results may be improved by early diagnosis and better operative technique and perioperative management.

Adolescent↗
PubMed1988

[Long-term results of transluminal valvuloplasty in calcified aortic valve stenosis].

Transluminal valvuloplasty (TVP) was attempted in 11 patients, aged 38-82 years, with calcified aortic valve stenosis (AS). The transvalvular systolic pressure gradient was reduced from a mean of 91 +/- 28 to 44 +/-30 mm Hg. Two patients had needed an emergency with decompensated AS in cardiogenic shock, died during the operation, another died of the consequences of an endocarditis. One patient had an inadequate TVP: a renewed TVP was subsequently performed at another hospital, followed by an operation for severe aortic regurgitation produced by the second TVP. In four patients left-heart catheterization 3-12 months post-dilation demonstrated considerable restenosis. One patient was significantly improved clinically (but no angiography had as yet been performed) four months after the TVP. Doppler echocardiography in this patient, too, demonstrated renewed increase in transvalvular pressure gradient. The results demonstrate that, because of the high rate of recurrence, TVP is at present only rarely indicated for calcified AS.

Adult↗
PubMed1988

Dose-dependent relaxation of human venous vessel strips with regard to chronic nitrate pretreatment.

Helical segments of human saphenous veins harvested at coronary bypass surgery were mounted in an organ-bath (Krebs-Henseleit buffer, pH 7.4; 37 degrees C; 95% O2/5% CO2 insufflation). After equilibration (60 min) and determination of basal tone the segments were depolarized and contracted by 24 mM potassium chloride. Then relaxation under isometric conditions was induced by cumulative concentrations of isosorbide dinitrate (ISDN) in a range of 10(-9) M to 10(-5) M. In vein segments from patients not pretreated with nitrates a concentration-response curve could be shown ranging from 8.4 +/- 4.5% to 71.9 +/- 8.6% (mean +/- SD). The relaxation pattern was not influenced by a 2-week pretreatment of patients with ISDN 20 mg twice daily or 40 mg four times daily even if the latter therapy was continued until 1 hour prior to surgery. Immersion of vessel strips in Krebs-Henseleit buffer containing 10(-6) M ISDN for 60 min prior to relaxation did not affect relaxation either. However, immersion of vessel segments in buffer medium containing 4.4 X 10(-4) M ISDN for 60 min led to a shift of the concentration-response curve by the factor 100 (EC50). Thus, chronic nitrate pretreatment of patients including high doses did not influence relaxation behaviour of isolated vessel segments. Induction of tolerance under in vitro conditions required concentrations exceeding the therapeutic limits. The most probable underlying mechanism is exhaustion of sulfhydril containing groups at the site of the smooth muscle cells. This hypothesis was supported by the finding that addition of cysteine into the organ-bath could widely reverse tolerance.(ABSTRACT TRUNCATED AT 250 WORDS)

Dose-Response Relationship, Drug↗