Biomedical subjects
Publications and source records attributed to M J Schweiger.
A method for inserting two catheters into a subclavian vein, using a single puncture, is described. Ten patients are reported in whom pulmonary arterial and temporary pacing catheters were inserted by this method. Similar techniques are discussed.
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A patient with prolonged duration, bacterial infection, and echocardiographic disappearance of an atrial myxoma following embolization is discussed. Following aortic saddle embolus, all echocardiographic manifestations of the patient's left atrial myxoma disappeared. Previous cases of infected atrial myxomas are reviewed. The necessity of early surgical intervention, despite active infection, is discussed.
Patients with a history of anaphylactoid reaction to radiographic contrast medium (RCM) are at increased risk for subsequent reaction. To date, 275 of these high-risk patients have been studied with use of prophylactic pretreatment with diphenhydramine hydrochloride or prednisone or both without a single severe anaphylactoid reaction on readministration of RCM. This report describes a patient who received pretreatment as described in the literature but suffered a life-threatening anaphylactoid reaction on readministration of RCM. Premedication does not eliminate the possiblity of a fatal reaction on readministration of RCM.
We compared visual estimate and digital caliper measurement of coronary stenoses, utilizing both a 50% and 70% diameter reduction as a definition of significance and both experienced angiographers and cardiology fellows as readers. Ten angiograms were interpreted twice, using the different methods, by four readers, two months apart. The angiograms were divided into 12 vessel segments. Stenoses were judged more severe by visual estimate in 11 segments. Seven of twelve segments had significant differences between readers using the visual estimate, but no significant differences were obtained using caliper measurements. Variability was highest for fellows using the visual method. Interobserver agreement was highest using the digital caliper and the 70% criteria. Intraobserver agreement was most dependent on the amount of time taken in film interpretation. The digital caliper appears to be preferable in interpreting angiograms, particularly for cardiology fellows.
BACKGROUND: Bolus thrombolytic therapy is a simplified means of administering thrombolysis that facilitates rapid time to treatment. TNK-tissue plasminogen activator (TNK-tPA) is a highly fibrin-specific single-bolus thrombolytic agent. METHODS AND RESULTS: In TIMI 10B, 886 patients with acute ST-elevation myocardial infarction presenting within 12 hours were randomized to receive either a single bolus of 30 or 50 mg TNK-tPA or front-loaded tPA and underwent immediate coronary angiography. The 50-mg dose was discontinued early because of increased intracranial hemorrhage and was replaced by a 40-mg dose, and heparin doses were decreased. TNK-tPA 40 mg and tPA produced similar rates of TIMI grade 3 flow at 90 minutes (62.8% versus 62.7%, respectively, P=NS); the rate for the 30-mg dose was significantly lower (54.3%, P=0.035) and was 65. 8% for the 50-mg dose (P=NS). A prespecified analysis of weight-based TNK-tPA dosing using median TIMI frame count demonstrated a dose response (P=0.001). Similar dose responses were observed for serious bleeding and intracranial hemorrhage, but significantly lower rates were observed for both TNK-tPA and tPA after the heparin doses were lowered and titration of the heparin was started at 6 hours. CONCLUSIONS: TNK-tPA, given as a single 40-mg bolus, achieved rates of TIMI grade 3 flow similar to those of the 90-minute bolus and infusion of tPA. Weight-adjusting TNK-tPA appears to be important in achieving optimal reperfusion; reduced heparin dosing appears to improve safety for both agents. Together with the safety results from the parallel Assessment of the Safety of a New Thrombolytic: TNK-tPA (ASSENT I) trial, an appropriate dose of this single-bolus thrombolytic agent has been identified for phase III testing.
BACKGROUND: Although the development of thrombus or dissection during percutaneous transluminal coronary angioplasty (PTCA) increases the risk of abrupt vessel closure, the magnitude of the effect is difficult to define. OBJECTIVE: The aim of the study was to determine prospectively the effect of the development of thrombus or dissection on PTCA procedural outcome. METHODS: Data from 591 consecutive angioplasty procedures involving 756 lesions at 9 clinical centers were included in a prospective registry with a core angiographic laboratory. RESULTS: Clinical success (defined as < 50% stenosis of all target lesions assessed in a core angiographic laboratory, with no major complications of death, Q wave or non-Q wave myocardial infarction or emergency CABG) was achieved in 497 patients (84%). Major complications occurred in 45 (7.6%). Abrupt vessel closure, including both established closure (TIMI grade 0 or I flow) and impending closure (> 50% stenosis, TIMI grade 0-2 flow, plus use of additional interventions) occurred in 65 patients (11%). Angiographically visible dissections developed in 40% of lesions; more severe grades of dissection were associated with reduced success rates, and increased incidence of and abrupt vessel closure and major complication. Angiographic evidence of thrombus (filling defects) developed in 12.3% of lesions; the presence of thrombus was associated with significantly lower procedural success (61% vs. 86%) and significantly higher rates of abrupt vessel closure (28% vs 7%) and major complications (24% vs. 6%). With multivariable analysis, thrombus was identified as an independent predictor of procedural success, abrupt vessel closure, and major complications. CONCLUSIONS: The development of severe dissections or thrombus following PTCA is associated with significantly lower procedural success rates and higher rates of abrupt vessel closure and major complications. Patients who develop severe dissection or thrombus may be appropriate candidates for more aggressive forms of therapy.