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Biomedical subjects

H Lambertz

Publications and source records attributed to H Lambertz.

82 records · Page 5Linked to original sources
PubMed1982

Percutaneous transluminal coronary angioplasty immediately after intracoronary streptolysis of transmural myocardial infarction.

Percutaneous transluminal coronary angioplasty (PTCA) was performed in 21 patients with acute myocardial infarction (AMI) treated by intracoronary infusion of streptokinase within 8 hours after the onset of symptoms. Streptolysis therapy began a mean of 3.6 +/- 1.2 hours (+/- SD) after the onset of symptoms. The vessel was occluded in 14 patients and highly stenosed in seven. After the infusion of 67,300 +/- 63,200 IU of streptokinase over 26.1 +/- 21.5 minutes, patency of the occluded vessels was reached. PTCA as performed 20-60 minutes after the end of streptokinase treatment in 19 patients and 24 and 31 hours after treatment in two patients. The dilation was successful in 17 patients (81%). The degree of vessel obstruction was reduced from 90.2 +/- 7.3% to 58.6 +/- 19.5% (area method) and from 71.4 +/- 12.4% to 39.2 +/- 19.7% (diameter method). The improvement was 31.5 +/- 18.4% and 32.2 +/- 19.3%, respectively. No reocclusion was induced by PTCA. Twenty patients were discharged. One died during hospitalization; at autopsy, the treated vessel was still patent. During the follow-up period, two reinfarctions and one asymptomatic reocclusion occurred. The clinical findings during the hospital course and the follow-up period were compared with those of a control group of 18 patients with AMI and comparable coronary stenoses who were treated only with streptokinase infusion. Four of these patients had a reinfarction during the hospital course, and three died during the follow-up period. PTCA can be performed safely and successfully immediately after intracoronary infusion of streptokinase in patients with AMI. By reducing the subtotal stenosis, this treatment contributes to the reperfusion of the ischemic myocardium, diminishes the risk of a reocclusion and seems to improve the prognosis.

Adult↗
PubMed1982

[Value of contrast echocardiography in the diagnosis of tricuspid insufficiency].

Contrast echocardiography utilizing peripheral saline injection was used for the detection of tricuspid regurgitation in 127 patients. In 36 patients prior to contrast echocardiography a tricuspid regurgitation was documented by angiography of the right ventricle. A V-wave synchronous pattern of contrast appearance in the inferior vena cava was detected by subcostal transducer position in 34 patients, and in 27 patients retrograde systolic flow lines across the tricuspid valve were documented by left parasternal transducer position. Correlated with angiographic data, the sensitivity of the method in the detection of a tricuspid regurgitation was 97% and the specificity 100%. False positive findings consisted in A-wave synchronous patterns and in heart-cycle-independent patterns of contrast appearance. Vena caval ultrasonography using size, pulsation, and inspiratory decrease in dimension was not helpful in predicting tricuspid regurgitation. A diameter of the inferior vena cava less than 10 mm/m2 BSA was indicative of normal right ventricular function.

Adult↗
PubMedDate not supplied

New miniaturized versus conventional biplane transesophageal transducers: recent clinical experience in adults.

A subset of patients have substantial discomfort on examination with transesophageal echocardiography with the conventional probe, whereby the dimensions of the probe play a decisive role. Miniaturized biplane transducers have recently become available (2 x 32 channels, dimensions 9.5 x 8.7 mm, and circumference approximately 30% less than the conventional echoscope) and allow ultrasound examination at 3.5, 5.0 and 7.0 MHz. A prospective study was carried out in 90 patients to compare difficulties on insertion of the probe, subjective evaluation by the patient during examination, and the two-dimensional image, as well as Doppler and color-coded Doppler quality of the miniaturized biplane versus the conventional probe. In 62 patients, intubation of the esophagus proved less difficult with the smaller instrument and more difficult in nine cases. Seventy-six patients reported that they suffered less discomfort on use of the narrow instrument. Concomitant parasympatholytic medication was needed with the smaller probe in seven cases and 17 times with the conventional probe. As anticipated, quality of the two-dimensional image attained by the miniaturized probe was lower. With transmit/receive frequency of 7.0 MHz, however, image resolution was excellent in the near field of 5 cm and nearly equivalent to that of the conventional probe (5.0 MHz). Pulsed-wave and continuous wave Doppler and color-coded Doppler information from both probes was similar in quality. Whenever examination with a conventional transesophageal transducer promises to be difficult, or when sedation is contraindicated because of a severe illness or respiratory insufficiency, transesophageal echocardiography should be considered with a smaller biplane probe at higher transmit-receive frequencies.

Adolescent↗
PubMedDate not supplied

Improvement of pulmonary venous flow Doppler signal after intravenous injection of Levovist.

The analysis of the pulmonary venous flow Doppler pattern can assist in the determination of the severity of mitral regurgitation and, in conjunction with transmitral flow pattern, the assessment of left ventricular diastolic dysfunction. In approximately one third of the cases, however, transthoracic ultrasonography is not able to record an adequately analyzable pulmonary venous flow pattern. The aim of the study was to examine and compare the effect of the echo-enhancing agent Levovist on the pulsed-wave Doppler flow quality of the transthoracic (TTE) and transesophageal (TEE) recorded pulmonary venous flow. In 26 consecutive patients a qualitative (score system) and quantitative analysis of pulmonary venous flow pattern was obtained before and after peripheral venous injection of Levovist at concentrations of 200 mg/ml (low dose) and 400 mg/ml (high dose). The amount of measurable studies for the antegrade pulmonary venous flow increased after the injection of Levovist from 85% to 96% for TTE and from 96% to 100% for TEE. The retrograde flow as seen by TTE was adequately analyzable in only 46% before and in 73% after the injection of Levovist (p < 0.02). Before any contrast enhancement the retrograde pulmonary venous flow recorded by TEE could be analyzed in 77% of the patients, with the percentage increasing to 88% and 92% after the administration of a low and high dose of Levovist, respectively (p < 0.05). In particular, the quality score of the retrograde flow was significantly altered by the administration of Levovist (increase from 1.8 +/- 1.0 to 2.6 +/- 1.1 [low dose Levovist], p < 0.05 and to 2.7 +/- 1.3 [high dose Levovist], p < 0.05). The pulsed-wave Doppler interrogation by TTE without Levovist underestimated the velocities of the antegrade and retrograde pulmonary venous flow. After Levovist was administered, the recorded values were comparable to those obtained by TEE. An analogous pattern is encountered when quantifying the duration of the retrograde flow component. Thus the peripheral venous injection of Levovist leads to an improved quality of the pulmonary venous flow Doppler signal recorded by TTE. On qualitative and quantitative evaluation the values recorded by TTE after administration of Levovist are comparable to those of the TEE technique without an echo-enhancing agent.

Adult↗
PubMedDate not supplied

A tricuspid polyurethane heart valve as an alternative to mechanical prostheses or bioprostheses.

The main disadvantages of today's heart valve prostheses are the need for lifelong anticoagulation for mechanical valves and problems with biodegradation for tissue valves. Therefore, a new valve type devoid of these problems would be a major step forward. In order to evaluate a new valve design made by dipmolding with different PU materials, an animal test series was carried out in which two valves from each material were implanted into the mitral position of growing Jersey calves. The surgical procedure and postoperative catheterization data are presented. The survival times ranged between 127 and 291 days. Organs and explanted valves were examined post mortem according to general pathology standards. Specifically, the valves were histologically examined for calcium deposits and investigated by light microscopy, REM and EDAX. All explanted valves showed calcification and immobilization, but the results suggest that at least two PU materials attain survival times which are far beyond the lifetime of bioprostheses under the same implant conditions, justifying further in vivo studies in adult animals.

Animals↗