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Biomedical subjects

B Meier

Publications and source records attributed to B Meier.

At least 37 records · Page 2Linked to original sources
PubMed1995

Coronary interventions in Europe 1992. The Working Group on Coronary Circulation of the European Society of Cardiology.

The general practice of coronary interventions is influenced by various aspects, traditional, cultural, socioeconomic and personal. The aim of this survey was to collect the data on coronary intervention in all member countries of the European Society of Cardiology. The data from 12 of the 35 national members were missing or grossly incomplete and were therefore excluded from the analysis. CORONARY ANGIOGRAPHY: The total number of coronary angiograms was reported as 683,888, an incidence of 1009 +/- 1021 per million inhabitants (range 9 (Romania) to 3076 (Germany)). Germany (246,115 cases), France (144,754), the United Kingdom (76,296), Italy (45,517) and Spain (43,495) registered 81% of all the coronary angiograms performed. PERCUTANEOUS TRANSLUMINAL CORONARY ANGIOPLASTY: (PTCA) The total number of reported PTCAs was 147,729, which on average accounted for 19 +/- 11% (range 2 (Lithuania) to 53% (Netherlands)) of the coronary angiograms. Most of the PTCAs (82%) were confined to a single vessel. The highest incidence of multivessel PTCA was reported from Slovakia (28%). PTCA took place immediately after the diagnostic study in only 18% of cases. Adjusted per capita, Germany ranked first with 703 PTCAs per million inhabitants, followed by Iceland (619), France (614), Belgium (568) and Austria (485). A major in-hospital complication was reported in 2.5% of the patients undergoing PTCA: 0.4% hospital deaths, 1.0% emergency CABGs and 1.1% myocardial infarctions. NEW DEVICES: Stents were implanted in 3211 patients (2.7% of all PTCA patients), equally distributed between emergency situations (53%) and elective procedures. Other interventional devices were applied in 4133 cases (2.8% of all PTCA cases): directional atherectomy, rotablator, transluminal extraction catheter, laser and Rotacs accounted for 1452, 1232, 55, 558 and 222, respectively. Coronary ultrasound (1350 cases) and coronary angioscopy (373 cases) were rarely performed. CORONARY ARTERY BYPASS GRAFTING (CABG): A total of 63,477 patients underwent CABG in the reporting centres resulting in a PTCA/CABG ratio of 2.3. A significant under-reporting of surgery in the participating centres must be assumed. CONCLUSIONS: Although partial reporting might bias conclusions, several findings of this survey are noteworthy: (1) PTCA was a well accepted treatment for coronary artery disease, (2) PTCA was applied more frequently than CABG, (3) there was an extremely wide range of coronary angiography and PTCA performed per million inhabitants, (4) the most common additional procedure was stent implantation, but other new devices were only rarely applied.

Angioplasty, Balloon, Coronary↗
PubMed1995

[Blood thinning in heart patients].

Virtually all modalities of anticoagulation play a role in cardiology. For primary prevention, aspirin showed no effect in a British study, but reduced the incidence of myocardial infarction by 44% per year in an American trial concerning men and by 32% concerning women. In patients with pre-existing coronary artery disease, the effect was even more marked. For unstable angina, several regimens were tested. Aspirin and heparin were the drugs most frequently used, either as single therapy or combined. They both proved efficacious, and so did ticlopidine. Promising results were also obtained with hirudin, a specific thrombin antagonist. For the treatment of acute infarction, the roles of aspirin and vitamin-K antagonists are soundly established. Aspirin reduces not only mortality but also other cardiac events. Coumadin has an even more impressive record. It reduces mortality by 25 to 35% and recurrent infarctions by 50%, with an acceptable risk for cerebral hemorrhage (1 to 2% per year). After coronary revascularization, aspirin is the therapy of choice for both coronary angioplasty and bypass surgery, with a few exceptions (poor left-ventricular function, stents in small arteries, etc.). Ticlopidine seems to be a valid alternative. Artificial heart valves require coumadin, with the exception of bioprosthesis in patients without additional risk factors. The same holds true for atrial fibrillation, except for the lone variety in young patients. Every cardiologist has to be cognizant of the armamentarium of anticoagulants and thoroughly trained in their indications and handling.

Adult↗
PubMed1994

[Balloon valvuloplasty of a discrete subvalvular aortic stenosis].

We describe the successful percutaneous balloon valvuloplasty of a discrete subaortic stenosis in an adult patient. The maximal gradient of 160 mm Hg (mean 100) was reduced to 45 and 33 mm Hg respectively. The procedure required only one overnight hospital stay.

Adolescent↗
PubMed1994

Regulation of an in vivo metal-exchangeable superoxide dismutase from Propionibacterium shermanii exhibiting activity with different metal cofactors.

The anaerobic, but aerotolerant Propionibacterium freudenreichii sp. shermanii contains a single superoxide dismutase [EC 1.15.1.1.] exhibiting comparable activity with iron or manganese as metal cofactor. The formation of superoxide dismutase is not depending on the supplementation of iron or manganese to the culture medium. Even in the absence of these metals the protein is built in comparable amounts. Bacteria grown in the absence of iron and manganese synthesize a superoxide dismutase with very low activity which had incorporated copper. If the medium was also depleted of copper, cobalt was incorporated, leading to an enzymically inactive form. In the absence of cobalt an enzymically inactive superoxide dismutase was built with unknown metal contents. Upon aeration the amount of superoxide dismutase activity increased continuously up to 9 h, due to a de novo synthesis of the protein. This superoxide dismutase had incorporated iron into the active centre. The superoxide dismutase of Propionibacterium shermanii is able to form a much wider variety of complexes with trace metal ions in vivo than previously recognized, leading to the hypothesis that the original function of these proteins was the binding of cytoplasmic trace metals present in excess.

Bacterial Proteins↗
PubMed1994

[Thrombolysis in acute myocardial infarct].

Thrombolysis for acute myocardial infarction is based on the discovery some 80 years ago that the total occlusion of a coronary artery is universally due to a thrombus. In the eighties, thrombolysis has become established as the therapy of choice for infarction, and its value has since been proved in large randomized studies. First, the ISIS-2 study showed the efficacy of streptokinase alone and in combination with aspirin in reducing mortality. The GISSI study corroborated these data. The ISIS-3 study and the GISSI-2 study (complemented by the International Study) failed to show a difference in efficacy between TPA and streptokinase. Anistreplase (APSAC) proved inferior to the other two drugs. The GUSTO study (over 40,000 patients) revealed a minor advantage of an accelerated regimen of TPA compared with the usual streptokinase dose. TPA was combined with intravenous heparin. According to the data gathered in American centers, about one life could be saved per 100 patients treated albeit at the considerably higher price of the TPA. European data suggest that it may only be one life saved per 200 treated patients. The main complication of thrombolysis is bleeding. The more efficient the thrombolytic treatment is, the higher the bleeding rate. Cerebral insults (particularly hemorrhages) are increased in patients with thrombolysis complemented by aspirin and heparin. However, these complications do not completely forfeit the beneficial effect of the two adjunctive medications on cardiac mortality. It has emerged that intravenous heparin is not essential in the first hour of TPA treatment but because important thereafter, whereas it may be essential in the first hour of streptokinase treatment but deleterious thereafter.(ABSTRACT TRUNCATED AT 250 WORDS)

Age Factors↗
PubMed1994

[Direct coronary angioplasty in acute myocardial infarct].

Direct (primary) coronary angioplasty for acute myocardial infarction has appeared in the literature since 1982, first as a rescue therapy in case of failed intracoronary thrombolysis, then as its complement, and finally as an alternative. In the late eighties, the upsurge of intravenous thrombolysis turned the focus off direct angioplasty until several randomized studies demonstrated the superiority of angioplasty in 1993. For an infarction primarily due to a thrombus, it is the treatment of choice. However, there is no accurate way to predict these lesions. Direct angioplasty yields results comparable with the best published results of thrombolysis. However, the patients included in the thrombolysis studies usually present less severe clinical pictures than those undergoing angioplasty. On the average, direct angioplasty is successful in 90%, reocclusion occurs in 11%, and emergency bypass surgery becomes necessary in 3%. Hospital mortality is 7%. The risk factors known from thrombolysis also apply to direct angioplasty, such as multivessel disease, old age, cardiogenic shock and duration of infarction. Failed angioplasty is also a harbinger of death. In randomized comparisons with thrombolysis, an initial 30-45 minutes delay from decision to treatment because of preparations for cardiac catheterization was noted which converts to a time gain until reperfusion of about 1 hour in favor of angioplasty. Hospital mortality is reduced with angioplasty. Cerebral bleedings were confined to thrombolysis. Ejection fraction at rest or on exercise was better after angioplasty in two studies, and there is a clearcut reduction in the need for further interventions, resulting in an economic benefit in favour of direct angioplasty. A randomized study demonstrated that it was deleterious to routinely complement direct angioplasty with intravenous streptokinase. Direct angioplasty establishes patency earlier than thrombolysis and has a better overall hospital and long term course, probably because it eliminates the lesion in most cases rather than just recanalizing the vessel. It should be used in all patients with acute myocardial infarction provided not more than 30 minutes are lost for its organization. Otherwise, thrombolysis is the preferred treatment. Direct angioplasty is particularly desirable in patients with large infarctions of short duration. Its role for infarctions presenting with cardiogenic shock is currently under evaluation.

Adult↗
PubMed1994

[Cardiac interventions in Switzerland 1992. PTCA and Fibrinolysis Work Group of the Swiss Cardiology Association].

In 1992, 14,348 coronary angiographies were performed in Switzerland (2110 per 1 million population). This represents a 10% (+1332) increase over the previous year. About 50% were performed at university hospitals. Over the past 5 years, interventions for myocardial revascularization (coronary angioplasty [PTCA] and coronary artery bypass grafting [CABG] have increased constantly and nearly linearly. The increase from 1991 to 1992 was 8% (510) (PTCA: +18% [+469]; CABG: +1% [+41]). The PTCA/CABG ratio amounted to 0.9/1 for all Swiss hospitals. At university hospitals, angioplasty was performed more frequently than bypass grafting (PTCA/CABG 1.3/1) in contrast to the private hospitals (PTCA/CABG 0.4/1). More than a third of all revascularizations were performed in private hospitals. The increase in angioplasty is a consequence of an increase in coronary angiography and not of an increase in the percentage of multivessel PTCAs. This indicates that coronary artery disease is being diagnosed and treated more actively without necessarily adopting more aggressive PTCA indications. There was an obvious difference in morbidity and mortality rates, both after PTCA and CABG, between some private and public hospitals. The fact that public hospitals are obliged to accept high risk emergency cases is to their disadvantage. So is their more complete data collection, which reveals the actual incidence of complications more accurately.

Angioplasty, Balloon, Coronary↗
PubMed1994

In vivo incorporation of cobalt into Propionibacterium shermanii superoxide dismutase.

Propionibacterium shermanii, an aerotolerant anaerobic bacterium, has already been shown to incorporate, depending on the metal supplementation to the medium, either iron or manganese or copper into the same superoxide dismutase protein. The in vivo incorporation of cobalt in the same superoxide dismutase was obtained in an iron-, manganese- and copper-depleted medium. The protein was isolated and characterized by NMR which offers the possibility to identify the amino acid residues at the active site exploiting isotropically shifted proton resonance.

Cobalt↗
PubMed1994

[Myocardial infarct in patients with normal coronary arteries].

Between November 1992 and April 1993, 864 coronary angiographies were performed at our institution. In 14 patients (1.6%), no significant coronary disease (> 50% stenosis) was found despite documented myocardial infarction. Of these, 2 patients (0.2%), aged 46 and 33 years, had perfectly smooth coronary arteries at angiography. The most commonly postulated mechanism of myocardial infarction in such patients is coronary spasm with superimposed thrombosis. The same risk factors as those operative in atherosclerotic coronary artery disease are thought to play a role in this setting. The prognosis is good. In one of the patients with < 50% stenosis of coronary vessels, a history of cocaine abuse could be elicited as the possible causal factor of acute myocardial infarction. Cocaine-induced coronary spasm can lead to arrhythmias, myocardial infarction or accelerated coronary atherosclerosis even in patients with normal coronary arteries. Myocarditis must be considered in the differential diagnosis of acute myocardial infarction in young patients with chest pain, typical electrocardiographic and enzymatic changes but without risk factors.

Adult↗
PubMed1994

[Successful thrombolysis of a thrombosed mitral valve prosthesis].

Thrombosis of a cardiac valve prosthesis is a rare but life-threatening event. The diagnosis may be suspected clinically and verified by Doppler echocardiography and/or fluoroscopy. Thrombolysis is being increasingly used as an alternative to emergency surgery (thrombectomy or prosthesis replacement). We describe the clinical course of successful thrombolysis of a thrombosed double leaflet Carbomedics No 29 prosthesis in mitral position, using urokinase, in an elderly female presenting with severe NYHA class IV dyspnea. Thrombolysis should be considered as a first line of treatment for thrombosed cardiac valve prostheses. The addition of a platelet inhibitor is warranted in patients with an episode of prosthetic cardiac valve thrombosis under adequate oral anticoagulation.

Aged↗
PubMed1994

Coronary angioplasty for isolated non-dominant left circumflex coronary artery disease.

The study describes the clinical findings and results of coronary balloon angioplasty in 134 patients with non-dominant left circumflex coronary artery disease. The immediate angiographic success rate was 97% versus 95% for left anterior descending (P = NS), and 90% for right coronary lesions (P < 0.002). There was no hospital mortality in the circumflex group versus 1.2% in the left anterior descending (P < 0.01), and 0.4% in the right coronary artery group (P = NS). Major non-fatal cardiac complications were significantly lower in the non-dominant left circumflex coronary artery patients (no new Q-wave versus 3% in the left anterior descending, P < 0.0002, and 3% in the right coronary artery group, P < 0.01; no urgent coronary artery bypass grafting versus 2% in the left anterior descending, P < 0.001, and 1% in the right coronary artery group, P = NS). The freedom from chest pain was 63% in 112 patients (84%) with follow-up data available at 24 +/- 18 months, and mean angina class diminished to 0.7 +/- 1.3 (P < 0.001). Consumption of antianginal and other cardiac drugs was diminished during follow-up, and the number of patients on no such drugs increased from 5 to 32% (P < 0.001). Restenosis was found in 19 of 32 patients with repeat coronary angiography (59%). Repeat angioplasty was required in 22 patients during follow-up and in 4 of them (18%) it was done for new lesions. Angioplasty for isolated non-dominant left circumflex coronary artery disease yields excellent immediate and long-term results.

Angioplasty, Balloon, Coronary↗
PubMed1994

Interventional cardiology: state of the art.

Since the advent of percutaneous transluminal coronary angioplasty (PCTA) in 1977, a new breed of cardiologists was born "Interventional Cardiologists". To date, a wide range of new interventions have been developed including percutaneous closure of atrial septal defects and balloon dilatation of the pulmonary valve and mitral valvuloplasty among others. In 1994, the final position of interventional cardiology is not fully defined but indicates what can be expected in the near future. Conventional coronary angioplasty presently accounts for over 90% of all coronary interventions and is likely to remain the cornerstone of coronary interventions. New techniques include stents which have been shown to be effective in acute and threatening occlusions as part of the armamentarium against restenosis. The Rotablator is a technique which uses an olive-shaped high-speed burr coated with diamond chips used for debulking lesions though to represent a high risk/low success rate for balloon angioplasty. Directional coronary atherectomy, transluminal extraction catheters, and Rotacs (a low-speed rotator) have also been developed. Laser angioplasty, which initially created great enthusiasm, probably will be of limited use. Mitral balloon valvuloplasty has emerged as the most common balloon valvuloplasty performed world-wide. It can be performed with or without fluoroscopy, particularly useful in pregnant women. Balloon valvuloplasty is also the treatment of choice in cases of pulmonary stenosis and balloon dilatation of the aortic valve, initially developed for children is now indicated in adults with the exception of elderly patients with calcified valves for whom valve replacement is indicated. Other interventions currently performed include balloon angioplasty for aortic coarctation following surgical repair and transcatheter closure of shunts. Patent ductus arteriosus, atrial septal defect and ventricular septal defect are choice indications. Certain congenital heart diseases including the creation of atrial septal defects in neonates whose survival depends on such a shunt and the treatment of pulmonary branch stenosis, venous obstructions, discrete subaortic stenoses and dilatation of the infundibular stenosis. Coil embolization of arteriovenous fistulae has also been developed. Finally, ablative techniques of invasive electrophysiology have further widened the indications of interventional techniques in cardiology which will continue to develop as an important pole of research and clinical applications in the future.

Angioplasty, Balloon↗
PubMed1994

In vivo incorporation of copper into the iron-exchangeable and manganese-exchangeable superoxide dismutase from Propionibacterium shermanii. Amino acid sequence and identity of the protein moieties.

Propionibacterium shermanii, an aerotolerant anaerobe, produces an iron-containing or a manganese-containing superoxide dismutase, depending on the metal supplied in the culture medium [Meier, B., Barra, D., Bossa, F., Calabrese, L. & Rotilio, G. (1982) J. Biol. Chem. 257, 13977-13980]. In this study, we demonstrate in vivo incorporation of copper into an active superoxide-dismutase protein when iron and manganese are absent from the growth medium. Superoxide dismutases containing either iron, manganese or copper were isolated from P. shermanii, their complete amino acid sequences were determined and the identity of their protein moieties was established. The polypeptide chain is made up of 201 amino acid residues, corresponding to a molecular mass of 22.6 kDa. From sedimentation equilibrium experiments, the native protein shows a molecular mass of approximately 86 kDa and therefore consists of four identical subunits. The primary structure was compared with the structure of other Fe-superoxide dismutases and Mn-superoxide dismutases, in particular those possessing a strict metal cofactor specificity.

Amino Acid Sequence↗
PubMed1994

Improving results of bailout coronary stenting after failed balloon angioplasty.

Stent implantation can be a valuable alternative to emergent bypass surgery to treat established or threatening abrupt closure following coronary balloon angioplasty. To evaluate several sequentially introduced changes in our practice of bail-out stenting, we compared the first (group I) and second half (group II) of our single center experience (n = 88). Use of bailout stenting increased over time (2% of all angioplasty procedures in group I vs. 6% in group II, P < 0.001), more often to prevent rather than to reverse abrupt closure. Technical success of stent implantation was unchanged (95% vs. 93%), and there was a decreasing trend for stent thrombosis (14% vs. 5%), in-hospital death (5% vs. 2%), Q-wave myocardial infarction (9% vs. 7%), and requirement for surgery (9% vs. 7%). The incidence of non-Q-wave myocardial infarction (29% vs. 7% P < 0.01), bleeding complications (27% vs. 7% P < 0.01), and hospital stay duration (11 +/- 11 vs. 8 +/- 5 days P < 0.05) decreased. Our data suggest that coronary stent implantation is currently an effective stand-alone bailout procedure for a large majority of failed angioplasty procedures.

Aged↗
PubMed1994

Use of half (disarticulated) Palmaz-Schatz stents for thrombus-containing coronary lesions.

Coronary stenoses associated with thrombus can lead to poor angioplasty results and increased procedural complications. Stenting in the presence of thrombus is associated with an increased risk of stent thrombosis. We report eight patients in whom half a Palmaz-Schatz stent was implanted for inadequate angioplasty results owing to thrombus. Stenting resulted in improved angioplasty results; no stent thrombosis occurred.

Angioplasty, Balloon, Coronary↗