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G D Kneissl

Publications and source records attributed to G D Kneissl.

17 recordsLinked to original sources
PubMed2005

Low-dose aspirin for secondary cardiovascular prevention - cardiovascular risks after its perioperative withdrawal versus bleeding risks with its continuation - review and meta-analysis.

OBJECTIVES: Low-dose aspirin given for secondary prevention of cardiovascular disease is frequently withdrawn prior to surgical or diagnostic procedures to reduce bleeding complications. This may expose patients to increased cardiovascular morbidity and mortality. Aim of the study was to review and quantify cardiovascular risks because of periprocedural aspirin withdrawal and bleeding risks with the continuation of aspirin. METHODS: We screened MEDLINE (January 1970-October 2004) with additional manual cross-referencing for clinical studies, surveys on the opinions of doctors and guidelines. RESULTS: Studies reporting the relative risk of acute cardiovascular events after aspirin withdrawal when compared with its continuation were not found. However, retrospective investigations revealed that aspirin withdrawal precedes up to 10.2% of acute cardiovascular syndromes. The time interval between discontinuation and acute cerebral events was 14.3 +/- 11.3 days, 8.5 +/- 3.6 days for acute coronary syndromes, and 25.8 +/- 18.1 days for acute peripheral arterial syndromes (P < 0.02 versus acute coronary syndromes). On aspirin-related bleeding risks, we obtained 41 (12 observational retrospective, 19 observational prospective, 10 randomized) studies, reporting on 49 590 patients (14 981 on aspirin). Baseline frequency of bleeding complications varied between 0 (skin lesion excision, cataract surgery) and 75% (transrectal prostate biopsy). Whilst aspirin increased the rate of bleeding complications by factor 1.5 (median, interquartile range: 1.0-2.5), it did not lead to a higher level of the severity of bleeding complications (exception: intracranial surgery, and possibly transurethral prostatectomy). Surveys amongst doctors on the management of this problem demonstrate wide variations. Available guidelines are scarce and in part contradictory. CONCLUSIONS: Only if low-dose aspirin may cause bleeding risks with increased mortality or sequels comparable with the observed cardiovascular risks after aspirin withdrawal, it should be discontinued prior to an intended operation or procedure. Controlled clinical studies are urgently needed.

Acute Disease↗
PubMed2000

[A standardized documentation structure for data documentation in echocardiography. Work Team on Standards and LV Function of the Work Group on Cardiovascular Ultrasound of the German Society of Cardiology, Heart and Circulation Research].

Presently, there are no well-defined standards for documentation of echocardiographic studies. Nevertheless, standards are essential to provide comparability of data and to realize electronic communication, both essential for quality management in echocardiography. Therefore, the working group "Standards and LV function" of the German Society of Cardiology developed a consensus for documentation of echocardiographic studies. In the present paper this consensus is presented and illustrated by typical clinical examples. Additionally, a prototype of a user-oriented software based on this data set is presented. The complete data set for transesophageal and transthoracic echocardiography and the software prototype can be downloaded at http:@echo.ma.uni-heidelberg.de.

Aortic Valve Stenosis↗
PubMed1999

Outpatient coronary angiography with 4 French catheters.

The early 4 French (Fr), pre-formed, Judkins coronary catheters had unsatisfactory maneuverability due to reduced torque stability. Technical innovations have led to improved 4 Fr catheters. This prospective study evaluates the safety and feasibility of the 4 Fr Quick Care Infinity catheter (Cordis, Miami, Florida). Within a series of 2,366 patients investigated for suspected coronary artery disease, 302 were selected for outpatient treatment according to the guidelines for outpatient catheterization. Fluoroscopy time was 2.8 +/- 2.5 minutes. It was not necessary to change to larger catheters in any patient. After sheath removal, hemostasis was achieved within 14 +/- 8 minutes. Strict bed rest lasted 181 +/- 65 minutes; patients were discharged 303 +/- 76 minutes after arterial puncture. Sixteen of the 302 patients (5.3%; 95% confidence interval (CI): 3.1-7.9%) changed to inpatient treatment for reasons unrelated to the arterial access. Eight patients (2.6%; CI: 1.1-5.1%) required one night of hospitalization for control of hematoma. The following morning, vessel murmur, pain, and large hematoma (more than 10 cm diameter) occurred in 1 (0.3%), 6 (2.0%), and 6 (2.0%) patients, respectively. This necessitated hospital admission in 2 patients (0.7%; CI: 0.0-2.3%) for up to 2 days. Major entry site complications requiring blood transfusion or surgery did not occur (CI: 0.0-0.3%). It was concluded that outpatient catheterization for coronary artery disease using the new 4 French catheters is feasible and can be rapidly and safely performed in a selected patient population.

Adult↗
PubMed1998

Endothelium-dependent and endothelium-independent flow reserve in vascular regions supplied by the internal mammary artery before and after bypass grafting.

OBJECTIVE: It was the goal of this study to compare endothelium-dependent and endothelium-independent flow reserve in vascular regions supplied by the left internal mammary artery before and after bypass graft surgery. METHODS: The native internal mammary artery in situ was investigated in 13 patients (age 61.8 +/- 8.0 years) with angiographically proven coronary artery disease. The internal mammary artery after bypass grafting was investigated in ten patients (age 60.8 +/- 7.3 years) 3.5 +/- 2.8 years after the operation. Flow reserve was evaluated endothelium-dependent with acetylcholine (ACh 25 and 50 microg i.c.) and endothelium-independent with nitroglycerin (NTG 0.3 mg i.c.) followed by papaverin (10 mg i.c.). Flow indices were calculated from intraluminal Doppler blood flow velocity measurements and the vascular cross-sectional area as determined by quantitative angiography. An index for vascular resistance was defined as the ratio of pressure gradient and resting or peak flow. RESULTS: After endothelium-dependent stimulation with acetylcholine 25 microg (50 microg), flow in the internal mammary increased by 352.3 +/- 152% (412 +/- 145%) before surgery, whereas it increased only by 213 +/- 134% (193 +/- 120%) after surgery (P < 0.05). Endothelium independent stimulation with papaverin resulted in a flow increase of 391 +/- 234% before surgery vs. 315 +/- 135% after surgery (n.s.). The resistance index decreased after endothelium-dependent stimulation with acetylcholine 25 microg(50 microg) to 35 +/- 16.8% (28 +/- 8.9%) before surgery, whereas it decreased only to 59 +/- 26% (72 +/- 43%) after surgery (P < 0.05). Endothelium independent stimulation with papaverin resulted in a decrease of the vascular resistance index to 31 +/- 14% before surgery vs. 32 +/- 14% after surgery (n.s.). CONCLUSION: Vascular regions supplied by the internal mammary artery as a graft demonstrate a significantly reduced endothelium-dependent flow reserve but a preserved endothelium-independent flow reserve as compared to vascular regions supplied by the native internal mammary artery. The selective decrease in endothelium-dependent flow reserve may be due to microvascular changes in the myocardial region supplied by the internal mammary artery after bypass grafting.

Aged↗
PubMed1997

Right ventricular function before and after percutaneous balloon mitral valvuloplasty.

Aim of this study was to evaluate right ventricular performance in patients with mitral stenosis and its modification by balloon valvuloplasty. Right ventricular volumes of 24 patients with postrheumatic mitral stenosis were determined by thermodilution 1 or 2 days before and 1 or 2 days after valvuloplasty. Right ventricular ejection fraction at rest was 43 (36-47)% (median and interquartile range). Right ventricular end-diastolic volume was 100 (86-119) ml/m2. Supine bicycle exercise (50 Watt) reduced right ventricular ejection fraction to 30 (29-37)% (P < 0.0001) and increased right ventricular end-diastolic volume to 124 (112-141) ml/m2 (P < 0.0001). At rest, right ventricular ejection fraction correlated inversely with pulmonary vascular resistance (r = -0.64, P < 0.0001), while no significant correlation with mitral valve area was found. Valvuloplasty increased right ventricular ejection fraction at rest to 48 (44-50)% (P < 0.005), and during exercise to 42 (38-45)% (P < 0.0001). This improvement of right ventricular ejection fraction correlated inversely with the value of this parameter before valvuloplasty (r = -0.88, P < 0.0001) and with the gain in stroke volume (r = 0.57, P < 0.01). The right ventricular function curve, disturbed before commissurotomy, was reestablished by the procedure. In conclusion, at the here investigated stage of mitral stenosis right ventricular function is reversibly impaired. This is predominantly caused by the hemodynamic consequences of the valvular defect and not by an impairment of right ventricular myocardial function.

Adult↗
PubMed1997

Successful thrombolysis after prosthetic pulmonary valve obstruction under aspirin monotherapy.

In a 22-year-old woman with recent onset of left-sided chest pain and exertional dyspnea, echocardiography revealed obstruction of a St. Jude Medical bileaflet prosthetic valve (size 23 mm) in the pulmonary position. Oral anticoagulation had been replaced for the previous 7 years by aspirin as the sole antithrombotic treatment. The valve had been inserted 16 years ago for pulmonary atresia. Valve function was restored by systemic application of 9 million units of urokinase.

Adult↗
PubMed1995

[Acute hemodynamic effects of piroximone i.v. in patients with severe heart failure].

UNLABELLED: Forty patients (30 men, 10 women) with severe congestive heart failure NYHA III (n = 30) and IV (n = 10) due to coronary heart disease (n = 19) or dilative cardiomyopathy (n = 21) were enrolled in this study. Mean age was 57 years. Eight patients each received 0.25 mg/kg, 0.5 mg/kg, 1.0 mg/kg or 2.0 mg/kg piroximone intravenously or placebo (saline). Measurements were performed before and up to 4 h after drug administration using a Swan-Ganz right-heart thermodilution catheter. RESULTS: All changes stated were significant (p < 0.05). Pulmonary capillary wedge pressure was lowered by max. 27% (0.25 mg/kg) to 52% (2.0 mg/kg) 30 min after drug injection. Significant effects were seen for 60 (0.25 mg/kg) to 120 min (2.0 mg/kg). Mean pulmonary artery pressure decreased by max. 8% to 24% after 30 min. Effects lasted for 30 to 60 min. Cardiac index increased by max. 26% to 52% after 30 min. Significant changes occurred up to 4 h after 2.0 mg/kg. Systemic vascular resistance fell by max. 16% to 34%. Effect duration was 1 h (0.5 mg/kg up to 4 h) (2.0 mg/kg). Minor changes of arterial blood pressure (minus 7% after 0.5 mg/kg) and heart rate (minus 14% after 2.0 mg/kg) were seen. CONCLUSION: Small doses of piroximone i.v. increase cardiac output by about 20% while preload and afterload decrease by about 20%. For most cases no doses higher than 0.5 mg/kg will be needed for the treatment of severe congestive heart failure.

Adult↗
PubMed1993

[Right ventricular function in patients with rheumatic mitral valve stenosis. Effect of balloon mitral valvuloplasty].

UNLABELLED: Postrheumatic mitral stenosis might cause impairment of right ventricular (RV) function due to both an increase in RV afterload and rheumatic myocardial disease. Therefore, we investigated in 19 patients with postrheumatic mitral stenosis and sinus rhythm right ventricular volumes and hemodynamics by a computerized thermodilution catheter during rest and supine bicycle exercise. In 14 patients the investigation was repeated within 2 days after balloon mitral valvuloplasty. Resting RV ejection fraction was decreased (43 (15-53)%, median (range)) and correlated significantly with RV end-systolic volume index (r = -0.90), stroke volume index (r = 0.77), RV end-diastolic volume index (r = -0.76), heart rate (r = -0.69), pulmonary artery resistance (r = -0.69), and mean pulmonary artery pressure (r = -0.68). RV end-diastolic volume index was 107 (81-200) ml/m2. Exercise induced a decrease of RV ejection fraction to 36 (13-48)% at 50 Watt (p < 0.001), while it increased RV end-diastolic volume index to 131 (78-231) ml/m2 (p < 0.001). Balloon mitral valvuloplasty improved RV ejection fraction at rest from 41 (15-47)% to 48 (39-55)% (p < 0.005) and from 30 (13-46)% to 43 (27-56)% during exercise (p < 0.005). The increase of RV ejection fraction after valvuloplasty was caused by an increase in stroke volume, but not by a reduction in RV end-diastolic volume. CONCLUSION: Depending on the increased RV afterload, RV function is markedly depressed in mitral stenosis. An immediate and almost complete improvement of RV function occurs with the reduction of RV afterload after balloon mitral valvuloplasty.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1992

[Echocardiography findings in hypertrophic cardiomyopathies. Diagnostic value of different echocardiography procedures].

In the present paper, the contribution of TM 2D and Doppler echocardiography to the non-invasive diagnostic evaluation of hypertrophic cardiomyopathies is discussed. The selective use of various echocardiographic possibilities for the representation (visualization) of typical morphological and functional changes in hypertrophic myocardial diseases is described.

Cardiomyopathy, Hypertrophic↗
PubMed1992

[Use of collagen in sealing of arterial puncture holes after heart catheterization].

Percutaneously introduced absorbable purified bovine collagen was used to plug the hole at the site of femoral arterial puncture in 50 patients (42 men, 8 women; median age 58 [22-75] after percutaneous coronary angiography (n = 32; heparin dosage 100 IU/kg) or transluminal coronary balloon dilatation (n = 18; heparin dosage 200 U/kg). Local bleeding ceased after compression of 4 min in 48 of the 50 patients. A pressure bandage was needed additionally in the other two. Bed-rest lasted for 1-24 (median 19) hours. A haematoma of more than 6 cm diameter developed in five patients, but required neither transfusion nor surgical intervention. 39 of the 50 patients were re-examined after a median of 39 days: all of them had had a small pain-free swelling for 2-6 weeks over the puncture site. One patient developed a deep-vein thrombosis one week after the procedure, in another fever occurred after the same period, lasting for two days. These early findings are encouraging. The method may significantly shorten the time of arterial compression and bed-rest, as well as reduce the risk of a large haematoma after arterial punctures.

Adult↗
PubMed1992

Nonoperative closure of the patent ductus arteriosus: the Frankfurt experience.

Nonoperative closure of patent ductus arteriosus (PDA) by means of Ivalon plugs (according to the technique of Porstmann) was performed in 101 patients. Sixty-five patients were symptomatic, the Q p/Q s ratio exceeded 1.5 in 56 patients, and pulmonary hypertension (mean pulmonary artery pressure greater than 20 mmHg) was present in 50 patients. In 100/101 patients the PDA could be closed successfully. Ninety-nine patients were without any evidence of residual left-to-right shunt. In one patient a hemodynamically insignificant left-to-right shunt was found with color Doppler echocardiography. Complications were pulmonary embolism due to plug dislocation in two patients (12th and 14th patient; 2 and 7 weeks after the procedure, respectively). One of these patients underwent elective surgery with patch closure of the ductus and removal of the embolized plug. In the other patient the ductus was successfully closed with a second larger plug while the first plug was left in a peripheral pulmonary artery. Surgical revision of the femoral artery was required in six and blood transfusion in two patients. Deep venous thrombosis developed in two patients. During follow-up (total follow-up time more than 200 patient years) no late complications were observed. In conclusion, transfemoral catheter closure of PDA by means of Ivalon plugs is an effective method. It is applicable to adolescents and adults with a low complication rate. The ductus can be closed without residual left-to-right shunt. Long-term results are excellent.

Adolescent↗
PubMed1992

Acute and mid-term experiences with the Wiktor stent in acute complications and restenosis after coronary angioplasty.

We report about the 6-month follow-up of 28 consecutive patients treated with a new tantalum stent (Wiktor¿ stent, Medtronic, Inc.). Indication for stenting was the prevention of restenosis in eight patients (restenosis group), and threatening or acute closure after PTCA in 20 patients (acute closure group). Twenty-eight of 30 stents were successfully positioned in 27 of 28 patients (96%), whereas implantation failed twice in one patient. Immediate stent occlusion developed in two patients in the acute closure group (7.4%) Subacute stent occlusion was observed in three patients (11%), one in the restenosis group, two in the acute closure group, between 3 and 5 days after implantation. Coronary bypass surgery had to be performed in four patients (15%): one patient after failed stent placement, two after acute, and one after subacute stent thrombosis. Major bleeding complications related to the anticoagulative drug regimen occurred in nine patients (33%). Three patients (11%) died for reasons most probably not related to stent implantation. A 6-month angiographic follow-up revealed restenosis in two of 19 patients (11%), one patient in each group. Sixteen of the 27 stented patients (59%) reached 6-month follow-up without death, acute or subacute stent thrombosis, or restenosis. It is concluded that the Wiktor stent can be placed with a high rate of success. It may also reduce the risk of restenosis. The stent also offers the possibility to circumvent emergency bypass surgery in case of PTCA related vessel occlusion. Acute and subacute stent occlusion still remains an unsolved topic.

Adult↗
PubMed1991

[Acute effect of enoximone and captopril in patients with heart failure].

UNLABELLED: The acute effects of enoximone (E) and captopril (C) were compared in a single-blind, randomized, cross-over trial in 10 patients (P) (nine with dilative cardiomyopathy, one with coronary heart disease) with heart failure (NYHA Class III: 6P and Class IV:4P). Cardiac index (Cl, 1/min.nm(-2), mean pulmonary artery pressure (PAM, mmHg), and pulmonary capillary wedge pressure (PC, mmHg) were measured at baseline and 15, 30, and 60 min after 0.1 mg/kg C and 0.75 mg/kg E, respectively, followed by measurements at 15, 30, 60, 180, and 300 min after 0.2 mg/kg C and 1,5 mg/kg E, respectively. RESULTS: Cl was unchanged 60 min after 0.1 mg/kg C, increased 60 min after 0.2 mg/kg C by 7.7% from 2.1 +/- 0.5 to 2.4 +/- 0.5 (p = 0,001), and was unchanged after 5 h. Cl increased 60 min after 0.75 mg/kg E by 32.5% from 2.1 +/- 0.5 to 2.9 +/- 0.4 (p = 0.001), 60 min after 1,5 mg/kg E by 59% to 3.3 +/- 0.6 (p = 0,001), and after 5 h by 19% to 2.5 +/- 0.4 (p = 0.01). PAM was unchanged 60 min after 0.1 mg/kg C, decreased 60 min after 0.2 mg/kg C by 10% from 35.7 +/- 11 to 31.7 +/- 10, and was unchanged after 5 h. PAM decreased 60 min after 0.75 mg/kg E by 13% from 35 +/- 9 to 31 +/- 10 (p = 0.01), 60 min after 1.5 mg/kg E by 19% from 35 +/- 9 to 27 +/- 9 (p = 0.001), and was unchanged after 5 h. PC decreased 60 min after 0.1 mg/kg C by 23% from 24 +/- 8 to 19 +/- 9 (p = 0.05) and was unchanged 60 min und 5 h after 0.2 mg/kg C. PC decreased 60 min after 0.75 mg/kg E by 35% from 25 +/- 6 to 17 +/- 8 (p = 0,01) and 60 min after 1.5 mg/kg E by 47% to 14 +/- 8 (p = 0,001) and was unchanged after 5 h. CONCLUSION: The clinical trial showed that in P with chronic heart failure (NYHA III and IV) the acute increase of Cl and decrease of PC is higher after E than after C. The improvement of hemodynamics lasts longer after i.v. E than i.v.C.

Adult↗
PubMed1990

[Echocardiographic functional parameters of the left ventricle as a prognostic indicator in coronary heart disease].

The value of two-dimensional cross-sectional echocardiography for the estimation of the left ventricular function had been investigated in 241 consecutive patients with suspected coronary artery disease (CAD). The day before left heart catheterization the left ventricular volumes (EDV, ESV) as well as the global left ventricular ejection fraction (EF) were calculated from the RAO-equivalent in the 2D-echo and in addition the classification of the EF was visually performed from different cross-sections. The coronary angiography showed in 208/241 patients hemodynamically effective stenoses (lumen restriction greater than 50%). For 192/208 patients there were diagnostically usable 2D-echograms as well as clinical data over an observation period of 3 years and 7 months. The 2D-echo correspond quite well to the levocardiography for the calculation of the EDV with r = 0.75, with r = 0.85 for the ESV, and with r = 0.80 for the EF. The mere visual evaluation of the EF out of the 2D-echo agreed well in 84% of the cases to the quantitative determination. During the observation period 18/192 patients died; 17/18 of these patients of cardial causes. Out of the patients with normal EF in the 2D-echo only 3.5% died, with slightly reduced EF 10% died. With highly reduced EF mortality was with 40% significantly increased (p less than 0.001). Thus in patients with CAD unfavourable long-time prognosis may be quickly recognized by their markedly reduced left ventricular function in the 2D-echocardiogram, which shows favourable correspondence to invasive data.

Adult↗