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Biomedical subjects

U Kaufmann

Publications and source records attributed to U Kaufmann.

At least 37 records · Page 2Linked to original sources
PubMed1997

[Use and significance of intravascular ultrasonic imaging].

Intravascular ultrasound (IVUS) imaging of coronary arteries has recently become possible in vivo with the improvements achieved in the miniaturisation of ultrasound transducers. IVUS provides informations complementary to angiography, and is considered as the gold standard for the assessment of lumen size, plaque thickness and plaque distribution. As formerly demonstrated by pathological studies, IVUS also reveals an underestimation of plaque thickness with angiography and an incomplete assessment of the true morphologic distribution of the plaque burden. Among its clinical applications, IVUS can be used to monitor revascularisation procedures, and may provide very accurate measurements of progression or regression of coronary atherosclerosis and of the extent of posttransplant vasculopathy. IVUS was employed successfully to assess and optimize the results of percutaneous transluminal coronary angioplasty. Clinical studies have shown that the risk of restenosis is inversely proportional to the size of the postprocedural lumen. With the guidance of percutaneous transluminal angioplasty by IVUS, balloon size and inflation pressures were increased, and better results were obtained with larger lumen size in comparison to the results of the procedures assessed by angiography alone. These improvements contributed to abandon the anticoagulation after stent implantation in most cases. In spite of the valuable information provided by IVUS, its role in clinical settings should still be defined IVUS prolongs the revascularisation procedure and enhances its costs and risks. Thus, the cost effectiveness of IVUS in its clinical application should be determined by prospective studies.

Angioplasty, Balloon, Coronary↗
PubMed1997

[Current trends in coronary angioplasty].

Coronary angioplasty still is an area of intensive development. The publication of the BARI data confirms and consolidates previous findings that balloon angioplasty and bypass surgery are equivalent in terms of mortality and major complications over a mid-term follow-up period. However, balloon angioplasty has a high rate of reinterventions, and is not recommended in diabetic patients with multivessel disease. The question, whether direct PTCA is a better treatment strategy of acute myocardial infarction than thrombolytic therapy remains unsettled despite a slight advantage for direct PTCA in several small randomized trials. The role of coronary stents has continuously expanded over the last years, as a tool against acute as well as long-term complications of angioplasty. This success is partly due to the finding that antiplatelet agents such as ticlopidine offer an effective protection against subacute stent thrombosis. The introduction of the GP IIb/IIIa platelet receptor blockers has provided another powerful tool against acute thrombotic complications, leading to a more aggressive interventional strategy in acute coronary syndromes. The development of alternative "devices" has further slowed down because of repeated publication of negative clinical results. Although different forms of laser energy applications, of local drug delivery, and of local irradiation are interesting research areas, their current impact on clinical practice is small.

Angioplasty, Balloon, Coronary↗
PubMed1997

[Interventional treatment of heart valve diseases].

Percutaneous balloon valvuloplasty of stenoses has been introduced into medical practice in the late 70ies. Over the past decade, the method has evolved to a valid alternative to valve surgery in selected cases. Balloon valvuloplasty of isolated mitral stenosis is to date the therapy of choice and yields results comparable to those of surgery. It is even superior in only moderately diseased valves. However, the most frequent valve stenosis, that is aortic stenosis of the elderly, is not suitable for balloon dilatation. Dilatation of congenital aortic stenosis can be attempted if the valve is bicuspid or tricuspid. The recurrence rates for valvular stenoses after valvuloplasty are similar to those after surgical commissurotomy.

Aged↗
PubMed1997

[Myocardial revascularization in geriatric patients].

The results of percutaneous transluminal coronary angioplasty (PTCA) in 71 patients over 75 years of age were retrospectively analyzed and compared with those of 55 patients aged over 75 who underwent surgical revascularization (CABG) during the same time period (1992-1995). The main indication for revascularization was unstable angina. The clinical success in PTCA patients was 92%, with a lesion success rate of 93%. Major cardiac complications occurred in 5% of patients with an in-hospital mortality of 1%. The mean hospital stay was 4 days. During a follow-up period of 16 (range 1-36) months, 23% of patients treated with PTCA needed repeat revascularization (17% PTCA, 6% CABG) and 4 patients (6%) suffered nonfatal myocardial infarction. In-hospital mortality and complications were higher among the surgically treated patients (mortality 7%, major complications 45%), a fact probably related to their poorer clinical condition preoperatively. Repeat revascularization rate in the surgically treated group was 2%. The long-term mortality rate in both groups was 10%. Among long-term survivors, 92% of patients indicated that revascularization (PTCA or CABG) improved their quality of life. More than 80% led normal lives, and > 90% would undergo a second procedure if needed. In selected patients aged over 75, PTCA has a high immediate success rate with low complications and mortality. Long-term recurrence rate is high, however, and repeat revascularizations are frequent. Patient satisfaction after myocardial revascularization (PTCA or CABG) is excellent and the majority of elderly patients can lead an active and independent life.

Aged↗
PubMed1997

Intracoronary demonstration of adenosine-induced coronary collateral steal.

A steal phenomenon was detected by intravascular Doppler guidewire in a patient with a well collateralised coronary vascular area supplied by a reopened left circumflex coronary artery. This phenomenon accounted for the fall in blood flow velocity reserve during hyperaemic conditions to 50% of the baseline value. The collaterals must have been the cause of the steal phenomenon because complete revascularisation of the lesion barely reversed it.

Adenosine↗
PubMed1996

Endothelin and calcium antagonists in the skin microcirculation of patients with coronary artery disease.

BACKGROUND: Endothelin, a potent endothelium-derived vasoconstrictor peptide, is elevated in coronary artery disease (CAD); however, its pathophysiological role is uncertain. Calcium antagonists are widely used in patients with CAD. Using laser Doppler flowmetry, we investigated the influence of two endothelin antagonists and the calcium antagonist diltiazem on endogenous and exogenous endothelin in the skin microcirculation of CAD patients and healthy control subjects. METHODS AND RESULTS: Both endothelin antagonists and diltiazem applied intradermally induced vasodilation in CAD patients, which was more pronounced with the ETA/ETB antagonist than with the ETA antagonist or diltiazem. Exogenous endothelin led to profound vasoconstriction in CAD patients and healthy volunteers. Both endothelin antagonists and diltiazem blunted the vasoconstriction to exogenous endothelin in CAD patients and young healthy volunteers and less so in old healthy volunteers. However, compared with both endothelin antagonists, a 10-times-higher dose of diltiazem was required. Systemic diltiazem (240 mg, slow release) attenuated endothelin-induced vasoconstriction in CAD patients. Neurogenic vasodilation to exogenous endothelin was inhibited by both endothelin antagonists. CONCLUSIONS: This study demonstrates that endogenous endothelin of CAD patients contributes to the regulation of vascular tone in the skin microcirculation not only through ETA receptors but also possibly through ETB receptors. Diltiazem inhibited endothelin-induced vasoconstriction, but endothelin antagonists were slightly more effective. Thus, endothelin antagonists represent potent new tools to interfere with the vascular effects of endothelin in CAD patients. Future studies must confirm these findings in other areas of the circulation.

Administration, Oral↗
PubMed1996

[Catheter closure in atrial septal defects and open foramen ovale using the Sideris buttoned device].

Percutaneous nonsurgical closure is an alternative to surgical repair of a significant atrial septal defect (ASD) or a patent foramen ovale (PFO) associated with systemic embolism without other cause. We report the results of the first 35 patients (19 ASDs, 16 PFOs) in whom transcatheter closure was attempted. Diagnosis and follow-up were based on transesophageal echocardiography in the majority of cases. In all patients the "Sideris buttoned device" was used. A total of 19 patients (13 women) were treated for symptomatic ASD of the secundum type. The mean defect size before the intervention was 17 mm by echocardiography and 24 mm measured by balloon in the catheterization laboratory (stretched diameter) with a reduction to 4 mm after treatment measured by echocardiography. A total of 16 patients (5 women) underwent transcatheter closure of a PFO; 14 patients had had cerebral embolic events and 2 peripheral. During follow-up of 104 patient months, only one patient had a recurrent embolic event. He had at that time no occluder protecting the PFO after early embolization and extraction of the device.

Adolescent↗
PubMed1996

[Therapeutic measures following acute myocardial infarct: differential use of PTCA, surgery and drugs].

Myocardial infarction represents a crossroads in the natural history of coronary artery disease. The prognosis is determined by the severity of coronary artery disease, infarct size (and hence ejection fraction), and age of the patient. After infarction, patients may remain symptomless, or suffer angina, silent ischemia, reinfarction, heart failure or sudden death. Hence patient management after infarction includes (1) estimation of risk, (2) the use of stress tests to detect ischemia and rhythm disorders, (3) PTCA or bypass if required and (4) medical therapy. Cardiac catheterization is indicated in patients with angina or silent ischemia, non-Q wave infarction or large infarctus; its use is less well established in patients without ischemia and left ventricular dysfunction, but this indication is nevertheless increasingly accepted. PTCA is primarily utilized in patients with single or two vessel disease, while coronary bypass surgery is indicated in patients with left main or three vessel disease. All these measures are designed to improve symptoms and prognosis. For secondary prevention medical therapy should be used to treat cardiovascular risk factors (antihypertensive drugs, lipid-lowering drugs etc.), to inhibit platelets (aspirin, ticlopidine) or coagulation (coumarins), to block neurohumoral activation (betablocker, ACE-inhibitors), for vasoconstriction (calcium channel blockers, nitrates) and to suppress arrhythmias. The large number of drugs requires reasoned use depending on the risk profile of the individual patient. Cardiovascular risk factors should be treated appropriately. Platelet inhibitors should be given to all patients except those with atrial fibrillation or large ventricles (coumarins). Betablockers reduce mortality, reinfarction and sudden death after infarction and hence should be used if no contraindications exist. ACE-inhibitors are particularly effective in improving symptoms and prognosis in patients with impaired left ventricular function. Calcium antagonists should be used with caution and only in patients with normal left ventricular function. Nitrates are primarily effective in improving symptoms in patients with angina or heart failure. Antiarrhythmic drugs (amiodarone) are only useful in patients with complex arrhythmias. Digitalis has been shown to improve symptoms in patients with heart failure, while other inotropic drugs are virtually no longer used. These guidelines allow reasoned differential therapy after myocardial infarction to the maximum benefit of the patient and at minimum cost.

Adrenergic beta-Antagonists↗
PubMed1996

Ultrasound-guided compression repair for treatment of femoral artery pseudoaneurysm: acute and follow-up results.

Femoral artery pseudoaneurysm is a significant problem in patients undergoing arterial diagnostic or therapeutic catheterization. The aim of this investigation was to report the incidence of pseudoaneurysm after arterial catheterization and the success rate of ultra-sound-guided compression repair. During a 3-year period (11/91-11/94) 9,051 patients underwent 7,312 cardiac catheterizations and 1,739 peripheral percutaneous transluminal coronary angioplasty procedures. Patients suspect of pseudoaneurysm were referred for a color Doppler ultrasound examination. All patients with pseudoaneurysm were considered for ultrasound-guided compression repair. Pseudoaneurysm occurred more frequently after interventional procedures with new devices (valvuloplasty 2.3%, stent 3.2%) than after conventional catheterization diagnostic cardiac catheterization 0.2%, electrophysiology 1.3%, percutaneous transluminal coronary angioplasty 0.2%). The incidence of pseudoaneurysm after peripheral percutaneous coronary transluminal angioplasty, including intra-arterial lysis and stent, was 1%. Ultrasound-guided compression repair was successfully performed in 37 of 41 cases with pseudoaneurysm (90%). Ultrasound-guided compression repair was successfully performed in 30 of 31 patients (97%) without anticoagulation and in 7 of 10 patients (70%) receiving anticoagulants (P < 0.05). There was no correlation between mean diameter of the pseudoaneurysm, age of the lesion, or antiplatelet therapy. Color Doppler ultrasound re-examination at up to 3 months indicated successful treatment in all patients. The use of complex interventional catheterization procedures leads to an increased frequency of pseudoaneurysms compared with conventional angiography and percutaneous transluminal coronary angioplasty. Ultrasound-guided compression repair is a non-invasive, efficient, safe and cost-effective therapy for post-catheterization pseudoaneurysm.

Adult↗
PubMed1996

Congenital absence of the left pericardium with extreme intrathoracic displacement of the heart. Case report and review of the literature.

Large pericardial defects are exceptional and difficult to diagnose. A 62-year-old man underwent elective coronary surgery which was seriously complicated by the unexpected intrapleural position of the heart due to the absence of a large amount of pericardium on the left. It appeared retrospectively that the patient had presented typical signs of the malformation and these are described in detail.

Diagnosis, Differential↗
PubMed1996

High dose dipyridamole as a pharmacological stress test during cardiac catheterisation in patients with coronary artery disease.

AIM: To validate dipyridamole as a pharmacological stress test during cardiac catheterisation, allowing both functional and morphological estimation of stenosis severity. METHODS: The study encompassed 74 patients: 62 patients with significant coronary artery disease (age 61 (SD 8) years; seven women, 55 men) and 12 controls. Regional wall motion, left ventricular ejection fraction and end diastolic pressure were analysed in the resting state and after high dose intravenous dipyridamole. Patients were subdivided into four groups: group I (n = 32, 43%) had stopped all anti-ischaemic treatment for > 24 h, group II (n = 14, 19%) was under treatment, group III (n = 16, 22%) had significant coronary artery disease only in regions with regional wall motion abnormalities at rest, and group IV consisted of 12 control patients (16%) with no significant coronary artery disease (age 62 (8) years, three women, nine men). RESULTS: The sensitivity of dipyridamole testing in patients with coronary artery disease was poor. The best sensitivity was obtained with regional wall motion analysis (26/62 = 42%) and with global left ventricular ejection fraction (25/62 = 40%). Specificity was 100% for regional wall motion and 100% for ejection fraction. Calculated positive and negative predictive values for regional wall motion were 100% and 63%, respectively. CONCLUSIONS: Although safe, handy, and inexpensive, dipyridamole is not an adequate pharmacological stress test during cardiac catheterisation because of its low sensitivity.

Cardiac Catheterization↗
PubMed1996

Effect of pre-treatment with transdermal glyceryl trinitrate on myocardial ischaemia during coronary angioplasty.

OBJECTIVE: In the light of the reported inconsistent anti-ischaemic and antianginal effects of transdermal glyceryl trinitrate, its efficacy and influence on the effects of intracoronary glyceryl trinitrate were examined during coronary angioplasty, which provides a model of controlled, reversible ischaemia. DESIGN: Double blind, randomised study of the effect of transdermal and intracoronary glyceryl trinitrate on ischaemia during coronary angioplasty. PATIENTS: 40 patients with isolated severe stenosis of the left anterior descending coronary artery. INTERVENTIONS: Patients were randomised (double blind) to transdermal glyceryl trinitrate (10 mg per day) and placebo, starting four to six hours before angioplasty. After 4 one-minute balloon inflations intracoronary glyceryl trinitrate was injected (0.2 mg) and then 4 further one-minute inflations were performed. MAIN OUTCOME MEASURES: The time to angina and the time to > 0.2 mV ST shift on surface electrocardiogram (ECG) or intracoronary ECG during the individual inflations. RESULTS: These times did not significantly differ during initial inflations between transdermal glyceryl trinitrate (27 (11), 25 (9), and 19 (9) s, respectively) and placebo (34 (11), 30 (8), and 21 (7) s. After intracoronary glyceryl trinitrate, they were significantly prolonged compared with the initial values, without differences between patients with transdermal glyceryl trinitrate (37 (10), 30 (8), and 23 (8) s, respectively) or placebo (39 (15), 36 (11), and 28 (12) s). Ischaemic preconditioning was not seen. CONCLUSIONS: Transdermal glyceryl trinitrate (10 mg per day), unlike intracoronary glyceryl trinitrate, did not alleviate the myocardial ischaemia produced by balloon inflation during coronary angioplasty.

Administration, Cutaneous↗
PubMed1996

Low-dose thrombolysis for thrombosed prosthetic heart valve.

This report describes two cases of successful fibrinolysis of thrombosed tricuspid and mitral valve prostheses (Carbomedics; Austin, Texas) with low-dose urokinase therapy corresponding to only one third of the dose usually recommended.

Heart Valve Prosthesis↗
PubMed1996

Percutaneous Transluminal Coronary Angioplasty Through 5 French Diagnostic Catheters.

In 130 patients, coronary angioplasty (PTCA) with fixed wire balloons through 5 French (F) diagnostic catheters was performed immediately following diagnostic coronary angiography. Patients with complex lesions or in whom the need for alternative devices was likely such as stents were excluded. A total of 151 lesions were attempted. Primary success with 5F systems was achieved in 92% of lesions. In 7 cases, the 5F system failed to cross the stenosis and a change to a larger guiding catheter was necessary. Of these 7 cases, 6 could be dilated successfully with 6 or 7F systems. In one patient in whom the fixed wire balloon was not able to cross a subtotal stenosis of an obtuse marginal branch through the 5F catheter, a Monorail system through a 6F guiding catheter failed as well. The overall technical success rate was 96%. Cardiac complications occurred in 2% of patients (3 patients with Q-wave myocardial infarction). Two other patients (1.5%) with suboptimal PTCA results underwent bypass surgery. PTCA through small diagnostic catheters is a valid alternative technique in selected patients. It is safe and leads to high success rates. Advantages of this technique include 1) less peripheral and coronary trauma; 2) enhanced patient comfort; 3) economical advantages.

Journal Article↗
PubMed1995

[Mitral valvuloplasty using the Inoue balloon].

Percutaneous mitral balloon valvuloplasty (PMBV) is an accepted alternative treatment to open and closed mitral commissurotomy or mitral valvular replacement. The Inoue technique has become standard in most centers. In our first 24 percutaneous balloon mitral valvuloplasties by the Inoue technique, 23 procedures were technically successful. The mean age of the patients was 53 (24-75) years. There were 22 women. Four patients had a history of closed mitral commissurotomy, one of previous mitral balloon valvuloplasty, and one of aortic metallic valve replacement. The mean echocardiographic mitral Wilkins score was 7.3 (range 4-13). PMBV resulted in significant improvement of hemodynamic values. The mean mitral pressure gradient fell from 12 +/- 5 to 5 +/- 3 mm Hg (p = 0.0001) and the cardiac index increased from 2.7 +/- 0.7 to 3.0 +/- 0.8 l/min/m2. The valve area by the Gorlin formula increased from 1.2 +/- 0.3 to 2.1 +/- 0.6 cm2 (p = 0.0001). Doppler and planimetric echocardiography data were in keeping with hemodynamic data. Mitral valve regurgitation increased by more than 1 grade in 3 patients, 2 of whom subsequently underwent valve replacement. No tamponade occurred with the Inoue technique. There was 1 fatal outcome following tamponade and emergency heart surgery after mitral valvuloplasty with a Trefoil balloon employed in a subsequent intervention due to impossibility of placing the Inoue balloon. Left-to-right shunting at the atrial level after the intervention was not significant in any patient. 21 patients (88%) had improvement in their functional class. One of the patients with unchanged functional class had late onset of severe mitral regurgitation, another had a technical failure with the Inoue technique, and in 1 patient with calcified valve leaflets significant mitral stenosis persisted. At 3 to 15 months follow-up echocardiography was performed in 19 patients: mitral valve areas had not changed significantly compared to post-interventional values. One patient had a new mitral regurgitation compared with the situation immediately after PMBV. Mitral balloon valvuloplasty by the Inoue technique is an effective treatment with low risk in patients with symptomatic mitral stenosis.

Adult↗
PubMed1995

[Beta blockers in secondary prevention following acute heart infarct].

Prospective studies have confirmed a preventive effect of beta-adrenergic agents in the early as well as the late postinfarction period. In the early postinfarction period (first week), mortality is decreased by 13% by a lower incidence of myocardial ruptures and by stabilization of the size of the infarcted area. Prevention of reinfarction and sudden cardiac death in the late period of secondary prevention (up to six years) leads to additional reduction of mortality by 22 to 35%, depending on the risk group. The preventive effect of beta-blocking agents is not only attributed to their anti-ischemic properties but also to their antihypertensive, antiarrhythmic and antithrombotic effects. Beta-1-selective and not selective blockers show preventive effects. Beta-1-selective blockers are preferred because of fewer side effects. The effect of partially agonistic beta-blocking agents is low and thus of no use for secondary prevention. The elimination pathway and the price should be considered in the choice of the beta-blocking drug.

Acute Disease↗