Biomedical subjects
Publications and source records attributed to H Kreuzer.
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Beginning at October, 14th, 1981 until March, 10th, 1989 2015 PTCA-treatments on 1673 patients were performed in Göttingen. 2357 coronary lesions were treated, indicating an average of 1.17 lesions per treatment. During the observation period 1981 to 1986 versus 1987 to 1989 the subgroup of patients greater 65 years increased from 13.5% to 18.4% (p less than 0.01), while those patients with multivessel disease increased from 37% to 56% (p less than 0.001). During the compared observation periods the clinical success rate (all stenoses attempted greater than or equal to 20% reduced, no untowards events) was almost unchanged with 69%, versus 72%, respectively (p = n.s.). However, the rate of untowards events such as bypass grafting during the first 48 hours period decreased from 9.9% to 4.9% (p less than 0.001), the myocardial infarction rate decreased from 4.6% to 3.3% while the lethality rate stayed steadily low at 0.4%. Those nine years experience demonstrate in spite of older and sicker patients that the complication rate of PTCA procedures decreased while the success rate remained unchanged, a trend opposed to the development in coronary bypass grafting, where the complication rate increases due to older and sicker patients.
In a prospective study 38 patients (35 men, 3 women; median age 56 [37-71] years) with known coronary heart disease in whom conventional thallium-201 exercise-redistribution myocardial scintigraphy (ERMS) had demonstrated segments with diminished activity, thallium-201 was again injected ("reinjection scintigraphy"). Its purpose was to test whether in myocardial segments with persisting diminished radioactivity improved activity after reinjection provided evidence for still viable myocardium. Seven myocardial segments were evaluated in each patient, i.e. a total of 266 segments. Activity in the conventional ERMS was diminished in 94 of the 166 abnormal segments, but improved on reinjection in 21 of the 94 segments (22.3%). Nine of the 38 patients (23.7%) benefitted from the reinjection: only scar tissue without any viable myocardium would have been diagnosed by conventional ERMS in four patients, while extent and spread of ischaemic myocardium was better visualized in five.
Intravascular ultrasound imaging was performed in 15 patients (three women and 12 men; mean age 55 [48-70] years) after percutaneous balloon angioplasty of the right coronary artery (7 patients), the anterior interventricular branch (6) or the circumflex branch of the left coronary artery (2). The catheter, external diameter 4.8 F, was advanced over a 0.014--in coronary wire to the area of the previously balloon-dilated stenosis. Vessel diameter measured by ultrasound correlated closely with that by angiography (r = 0.93; P less than 0.001). Ultrasound imaging distinguished between concentric and eccentric intimal thickening and made it possible to assess the consistency and degree of calcification of the wall changes. The success of angioplasty was evaluated in 10 patients. In eight, local dissection was revealed, but only three of them had been diagnosed angiographically. In one patient a vessel spasm was recorded during ultrasound imaging; it regressed after the intracoronary injection of 0.2 mg nitroglycerin. There were no other complications. The method made it possible to assess in vivo the extent and consistency of atherosclerotic plaques, and it adds to the angiographic monitoring of treatment results and of complications after angioplasty.
The Wiktor stent, a new coronary balloon-expandable tantalum stent, was implanted in 17 patients for other wise nonmanageable occlusion after balloon angioplasty (n = 11) and for recurrent restenosis (n = 6). Stents of 3.0 to 4.0 mm were implanted (right coronary artery: n = 10, left anterior descending artery: n = 4, left circumflex artery: n = 2, venous graft: n = 1). All patients were fully anticoagulated initially with heparin followed by coumadin for 3 months and were treated with acetylsalicylic acid indefinitely. Due to its good radiopacity, the device could be placed easily without complications. Early occlusion occurred in one patient after 8 h probably due to friable atheromatous material prolapsing between the meshes of the stent. Late occlusion occurred in another patient who was admitted in cardiogenic shock after pre-hospital reanimation and was stented after occlusive disection following balloon angioplasty of an occluded right coronary artery. In this patient with severe hypoxic brain damage, reocclusion and reinfarction to which the patient finally succumbed occurred following cessation of anticoagulation. Histology demonstrated occlusive thrombosis without evidence of a neointimal covering of the stent. Another thrombotic occlusion due to inadvertent omission of anticoagulation occurred in another patient two weeks after stenting. Control angiography after 6 months in 12 patients revealed restenosis in two patients (50% and 80%). The patient with 80% restenosis of the right coronary artery and pathologic results during stress testing underwent surgical revascularization. The other patient with a 50% restenosis of the right coronary artery was managed medically as he was asymptomatic and without evidence of ischemia during stress testing.(ABSTRACT TRUNCATED AT 250 WORDS)
Immunoscintigraphy with a technetium-99m murine monoclonal IgG1 antibody directed against non-specific cross-reacting antigen (NCA-95) and carcinoembryonic antigen was performed with 20 patients with suspected subacute infective endocarditis (SIE) and 6 controls with suspected inflammatory/infectious disease elsewhere in the body. Immunoscintigraphy and echocardiography localised SIE in 11 of 15 patients in whom the disease could be confirmed. In 4 patients with validated SIE, the immunoscan was abnormal, and the echocardiogram was normal. In another 4 patients, the result was exactly the opposite. These findings suggest that the combination of immunoscintigraphy and echocardiography improves diagnostic efficacy in patients with suspected SIE.
An intravascular ultrasound catheter system was used in patients to assess the effect of percutaneous transluminal coronary angioplasty. In 14 out of 16 patients, the intravascular ultrasound catheter could be successfully advanced to the site of a previous dilatation. Qualitative assessment of the cross-sectional images revealed intimal thickening and an increase of ultrasound reflectance and calcification at atherosclerotic coronary arteries. A disruption of the obstructing plaque and evidence for local dissections (11 of 14 cases) were observed after angioplasty. The quantitative comparison between angiography and the ultrasound measurement showed a close correlation for vessel sites distant to the dilatation (r = 0.91 for vessel diameter; r = 0.86 for luminal area; p less than 0.001). After angioplasty, the quantitative evaluation of the dilated area was possible in 11 cases. The correlation of angiographic and sonographic measurements of these segments was good for the assessment of the vessel diameter (r = 0.82, p less than 0.001), but poor for the determination of the luminal area (r = 0.48, p = 0.10). This difference reflected the complex morphology of the vessel lumen after angioplasty, which would be better assessed by the cross-sectional sonographic technique than by contrast angiography. The intravascular imaging of coronary arteries provides a new and unique method to obtain information on the plaque morphology and composition, and to assess the local effects of interventional procedures and their complications.
The case of a 49-year-old patient is described who presented with cardiogenic shock and electrocardiographic signs of an inferolateral Q-wave infarction, and who received systemic lysis with anisoylated plasminogen streptokinase activator complex (Eminase). After coronary angiography had revealed only peripheral occlusion of a posterolateral branch of the left circumflex coronary artery, a pericardial effusion surrounding both right and left ventricular cavity was identified by echocardiography and was successfully drained via an inferior pericardiotomy with an immediate rise of blood pressure. Upon thoracotomy myocardial rupture was detected in the infarct area and was closed with mattress sutures. A total of 39 cases of successful surgical repair of myocardial free wall rupture reported in the literature is discussed. The mean age of patients was 59.6 +/- 1.3 years. Posterior and anterolateral infarctions were the preferred locations of myocardial rupture. Rupture occurred with a mean delay of 5.0 +/- 1.0 days after the onset of clinical infarct signs. Among patients saved by surgical means were 33 males and 6 females.
A study was designed to quantify the influence of the Hemopump on myocardial metabolism in regional myocardial ischemias induced by repetitive balloon-occlusions (3.5 minutes) of the LAD in 12 sheep (b.w. 49-61 kg). In order to make immediate comparisons and obtain paired-couples, ischemias were carried out with and without the Hemopump in operation. An energetic unloading of the left ventricle was achieved by the Hemopump already under preocclusion conditions, reducing myocardial O2-consumption from 7.52 to 5.98 ml/min/100 g LV (= 20%) as well as lowering the LVEDP from 13.3 to 9.8 mmHg (p less than or equal to 0.01). During ischemia a clear increase of LVEDP (13.3 to 21.0 mmHg) occurs, which was prevented in the group with Hemopump-assist (9.8 to 12.1 mmHg). Combined with a sustained higher diastolic aortic pressure, a better myocardial perfusion pressure resulted. Energetic unloading and improvement of perfusion conditions might be the cause of the significantly lowered release of lactate and potassium. Due to theses fibrillation (n = 3) only occurred during occlusions without Hemopump-support. In summary, a significant reduction of the ischemic burden on the myocardium was found. Thus the Hemopump could be of benefit to patients who fail to be weaned from CPB or who are suffering from instable cardiovascular performance.
Catheter ablation by radiofrequency energy was carried out in 10 patients with one type of recurrent monomorphic sustained ventricular tachycardia resistant to medical antiarrhythmic management. Electrophysiological studies before ablation included activation and pace-mapping. In all patients, the origin of the tachycardia was localized in the left ventricle: in the septum in six, at the posterolateral wall in three and anterobasal in one. The earliest onset of endocardial activation preceding the QRS complex during ventricular tachycardia ranged between -45 and -90 ms. Transcatheter ablation was performed with a bipolar or quadripolar catheter using a radiofrequency generator (HAT 100, Osypka). No complications occurred during the ablation procedure. Thereafter, in all patients, the clinical tachycardia was no longer inducible by programmed stimulation. During a follow-up period of 22 to 32 months including eight patients, the tachycardia recurred in two; one of these patients subsequently died suddenly. A third patient had one episode of a new type of sustained ventricular tachycardia some hours after catheter ablation. In the remaining patients, there was no recurrence of symptomatic tachycardia under maintenance of the antiarrhythmic management which, prior to ablation had been ineffective. Thus, our preliminary results suggest that radiofrequency catheter ablation might be beneficial for these high risk patients.
The results of coronary excimer laser angioplasty were evaluated in 70 patients. Forty-five patients had laser angioplasty of coronary stenoses. Twenty-five patients in a total of 35 attempts had wire-guided laser recanalization of chronic coronary occlusions, resulting in a success rate of 71%. Immediate results in both groups demonstrated the efficacy of this technique without serious side-effects. Stenoses were reduced from 90 +/- 5% to 48 +/- 18% diameter reduction (mean +/- standard deviation) by excimer laser angioplasty. Residual stenosis in recanalized vessels after laser angioplasty was 52 +/- 19%. In slightly more than half of the patients with a residual stenosis greater than 50% after excimer laser angioplasty, subsequent balloon angioplasty was performed for further stenosis reduction. While satisfactory immediate results were achieved by excimer laser angioplasty intermediate follow-up revealed a restenosis rate in the same range as with balloon angioplasty.
Late ventricular potentials detected by signal averaging are used for predicting ventricular arrhythmias and sudden cardiac death in patients with coronary artery disease. We studied the prevalence of signal-averaged late ventricular potentials in 37 male patients (mean age of 56 years) with angiographically normal coronary arteries. Seventeen patients were hypertensive (group A) and 20 patients were normotensive (group B). In group A, 5 of 17 patients (29%) had late ventricular potentials. In group B, only 1 of 20 patients (5%) had late potentials (p less than 0.05). Late ventricular potentials detected by signal averaging are more common in hypertensive patients than in healthy controls. Whether late ventricular potentials can be used to predict malignant ventricular arrhythmias or sudden cardiac death in hypertensive patients will have to be investigated in further studies.
The inspiration against a closed airway, the Mueller manoeuver, leads to a negative intrathoracic pressure. It is controversially discussed whether this is causing an augmentation of right heart murmurs. There is only limited knowledge on the temporal relationship of the negative intrathoracic pressure with right and left ventricular filling and stroke volume. To investigate this relationship, the flow through the mitral, aortic, tricuspid and pulmonary valves was studied continuously by Doppler echocardiography during a standardized Mueller manoeuver in 15 healthy subjects (age 45 +/- 10 years). Five heart beats after the initiation of the manoeuver, flow through the mitral and aortic valve decreased 12.2 +/- 7.2% (P less than 0.001) and 10.1 +/- 6.6% (P less than 0.001), respectively. A transient increase of 15.1 +/- 9.2% (P less than 0.001) in tricuspid flow was followed by a 14.3 +/- 9.8% (P less than 0.005) increase of flow through the pulmonary artery. Ten heart beats after the initiation of the Mueller manoeuver, flow through the pulmonary artery again reached baseline, while tricuspid flow remained below baseline values. In contrast to previous studies, our results indicate that the Mueller manoeuver causes a small and transient increase in right ventricular stroke volume which is unlikely to cause a marked augmentation in right heart murmurs.
The etiology of idiopathic dilated cardiomyopathy (DCM) is yet unknown; this study aimed at further differentiation of the disease by means of enzyme histochemistry. Endomyocardial biopsies from the left ventricle of 40 DCM patients and 5 control specimens had enzymes examined histochemically and semiquantitatively and analyzed according to staining intensities of nicotinamide adenine dinucleotide tetrazolium reductase (NADH-TR), succinate dehydrogenase, cytochrome c oxidase, lactate dehydrogenase and acid phosphatase (aPh). In DCM, the NADH-TR activity was elevated as compared to controls, indicating impaired mitochondrial oxidative phosphorylation. However, a concrete relation of enzyme histochemical intensity to anamnestic, hemodynamic or histomorphometric data could not be determined, except for the fact that the intensity of the lysosomal enzyme aPh was elevated in DCM patients with a relatively high left ventricular ejection fraction. The results demonstrate an interindependence of structural, hemodynamic and historical parameters as well as enzyme concentrations in DCM. Thus, a pathological change in the enzyme concentrations tested here cannot be responsible for the functional myocardial impairment in DCM.
A 64-year-old female patient with a prosthetic mitral valve suffered from recurrent typical angina and dyspnea. Left heart catheterization excluded a dysfunction of the prosthesis and coronary artery disease (CAD). A stress thallium scan demonstrated an ischemic reaction. An antimyosin scintigram was positive, indicating myocytal membrane disruption. Serological tests were suspicious for systemic lupus erythematosus (SLE). Therefore, an endomyocardial biopsy (EMB) was performed and a severe alteration of an intramyocardial artery, comparable with chronic SLE, was diagnosed. EMB is a useful diagnostic tool in patients with typical chest pain, positive thallium and anti-myosin scintigrams, however exclusion of CAD.
Changes in blood flow during restricted right coronary perfusion were studied in anesthetized rats. By use of a carotid-coronary shunt system, coronary perfusion pressure could be reduced to 40 mm Hg, leading to a fall in flow from 0.9 ml/min to 0.3 ml/min. The perfusion pattern within the flow-restricted area was determined by labelling the blood plasma with fluoresceinisothiocyanate (FITC) globulin (demonstration of the entire vascular system) and lissamine-rhodamine B200 (RB200) globulin (demonstration of actually perfused myocardial capillaries). In histological sections, arterial ramifications were evaluated with respect to the arrival of RB200 in their branches. Large filling defects were observed when flow was obstructed. After 10s labelling, in ramifications with a feeding artery larger than 15 microns in diameter, 10.5% of the vessels displayed dye in only one of the branches, and 13.5% in neither of the two branches. For smaller ramifications (less than 8 microns), these values amounted to 17.5% and 41.5%, respectively. A similar pattern was observed after vascular labelling for 60 s. When dihydroergotamine (2.0 micrograms/kg i.v.) was applied one minute after onset of occlusion, the perfusion inhomogeneity was significantly reduced (labelling in one branch and in none of the two, respectively: greater than 15 microns: 60% and 10.0%; less than 8 microns: 13.5%, and 26%). It can therefore be concluded that dihydroergotamine reduces hypoperfusion-induced inhomogeneity in myocardial blood flow.
Diastolic ventricular function was assessed by Doppler echocardiography in 50 patients with idiopathic dilated cardiomyopathy (DCM) and sinus rhythm. The patients were subdivided into two groups with either a moderately reduced ejection fraction (less than 32%; group 1, n = 25) or a severely reduced ejection fraction (less than 32%; group 2, n = 25), the latter having an unfavorable prognosis. The degree of heart failure according to the NYHA classification was more pronounced in group 2 (p less than 0.05). Mean pulmonary capillary wedge pressure (PCm) was also higher in group 2 (gr. 1:9.8 +/- 5.5 vs. gr. 2: 16.2 +/- 8.9; p less than 0.02), and the morphological parameters obtained by conventional M-mode echocardiography showed increased left ventricular volumes and mass in both groups with DCM, as compared with a control group (n = 16); there was a reduced volume/mass ratio in group 2. The parameters of systolic function derived from M-mode and Doppler echocardiography were reduced in patients with DCM, but were more pronounced in group 2. Doppler parameters of diastolic ventricular filling were differently affected in both groups with DCM. In group 1 there was a reduced contribution of the early diastolic phase to ventricular filling (FE/FA) (contr.: 2.29 +/- 0.99 vs gr. 1: 1.40 +/- 0.45; p less than 0.05) and a reduced early peak Doppler velocity, indicating an impaired ventricular relaxation. In group 2, as compared with controls and group 1, there was an increased ratio of early/late diastolic peak velocities (VE/VA) (contr.: 1.49 +/- 0.54 vs gr. 2: 2.32 +/- 1.37; p less than 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)
The aim of thrombolytic therapy for acute myocardial infarction is reperfusion of the infarction-related vessel. Ventricular late potentials detected by signal averaging have been demonstrated to be related to slow and inhomogeneous conduction within damaged cardiac tissue. In 75 patients with first myocardial infarction the effect of thrombolysis on ventricular late potentials was studied. Reperfusion of the infarction-related vessel could be demonstrated by coronary angiography in 53 (71%) patients. In 22 patients (29%) there was no reperfusion. In the 53 patients with successful thrombolysis the incidence of late potentials was significantly lower (9%) than in the 22 patients without reperfusion (50%). The lower incidence of late potentials may demonstrate improved ventricular electrical stability.