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Biomedical subjects

P Stulz

Publications and source records attributed to P Stulz.

At least 73 records · Page 4Linked to original sources
PubMed1991

Decision-making aspects in the timing of surgical intervention in aortic rupture.

Twenty-one consecutive patients with traumatic rupture of the thoracic aorta were treated at the University Hospital of Basel, Switzerland. The patients were divided into two groups according to their clinical status at the time of surgery. Six patients with unstable vital functions underwent immediate surgery (group 1), while 15 patients were operated upon semi-urgently because of delayed diagnosis or electively (group 2). Five of 6 patients undergoing immediate repair in group 1 died intraoperatively, 3 of 15 patients with deferred surgery expired postoperatively after a period of 6 weeks to 3 months. All 13 survivors underwent follow-up for 10 months to 20 years. NMR imaging of the aorta in 12 patients revealed neither pseudoaneurysms nor stenosis at the anastomoses. The results indicate that the timing of the surgical intervention in stable contained aortic rupture with serious associated injuries should preferably be deferred until after stabilization of the clinical status.

Adolescent↗
PubMed1991

Unusual localisation of a pulmonary hamartoma.

Hamartomas of the lung are usually located within the pulmonary tissue and sometimes within the bronchus. In this paper the rare case of a pedunculated epipleural hamartoma causing site-dependent chest pain is presented.

Female↗
PubMed1991

Different activation of the endothelial L-arginine and cyclooxygenase pathway in the human internal mammary artery and saphenous vein.

The endothelium releases substances controlling vascular tone and platelet function. We investigated mediators of endothelium-dependent responses in human internal mammary arteries and saphenous veins. The inhibitor of nitric oxide formation, NG-monomethyl L-arginine, enhanced the sensitivity to norepinephrine (fivefold) and evoked more pronounced endothelium-dependent contractions in internal mammary arteries (19 +/- 6% of 100 mM KCl) than in saphenous veins (2 +/- 1%; p less than 0.005). In internal mammary arteries, NG-monomethyl L-arginine, but not indomethacin, markedly reduced endothelium-dependent relaxations to acetylcholine (from 95 +/- 2% to 39 +/- 7%; p less than 0.005) and prevented those to histamine (78 +/- 6% to 4 +/- 3%; p less than 0.005). In saphenous veins, endothelium-dependent relaxations to acetylcholine were weak (24 +/- 11%), while nitric oxide caused comparable relaxations (85 +/- 3%) as in internal mammary arteries (80 +/- 5%; NS). NG-Monomethyl L-arginine prevented the relaxations to acetylcholine and unmasked endothelium-dependent contractions (30 +/- 10%). Indomethacin and the thromboxane synthetase inhibitor CGS-13080 augmented relaxations of saphenous veins to acetylcholine from 24 +/- 11% to 46 +/- 9% (p less than 0.05). Histamine-evoked contractions were converted to endothelium-dependent relaxations by indomethacin and the thromboxane A2/endoperoxide receptor antagonist SQ-30741 (38 +/- 3% and 40 +/- 6%; p less than 0.05) but not CGS-13080. Thus, 1) nitric oxide mediates endothelium-dependent relaxations in human arteries and veins; 2) internal mammary arteries release more nitric oxide than do saphenous veins, and 3) in saphenous veins, the effects of nitric oxide are reduced by endothelium-derived contracting factors originating from the cyclooxygenase pathway.

Acetylcholine↗
PubMed1991

[Traumatic ruptures of the thoracic aorta].

The authors present a group of 22 patients admitted for traumatic rupture of the thoracic aorta between 1969 and 1989. Most of them were polytraumatized patients (mean ISS 45). The majority of the injured patients possibly died before arriving at hospital. Amongst the other patients, there was a local tamponade of the hemorrhage. The risk of rupture of the patients arriving alive at the hospital is consequently restricted. The mortality of the patients operated in shock is high (3/4). The authors recommend to operate these lesions in delayed emergency.

Adult↗
PubMed1990

Prevention of aortocoronary vein bypass graft occlusion: which antithrombotic treatment and for how long?

The effects of 50 mg aspirin combined with 400 mg dipyridamole were compared with those of standard anticoagulant therapy, in the prevention of aortocoronary vein bypass graft occlusion. Early graft occlusion in 249 patients, with 749 distal vein graft anastomoses, were angiographically assessed 11.5 +/- 2 days after surgery and were almost equal in both treatment groups. In half of the patients in each group, active treatment was replaced by placebo after 3 months. Repeat angiography after 1 year (360 +/- 24 days) showed that more new late graft occlusions occurred in patients with only 3 months active medication (either regimen). The incidence of major complications was significantly higher in patients treated with anticoagulants, with minor side-effects more common in the antiplatelet group. Thus, this antiplatelet drug regimen was as effective as standard anticoagulant therapy in the prevention of early and late bypass graft occlusion, but carried a significantly lower risk of severe complications. In addition, as replacement of active treatment by placebo after 3 months resulted in significantly more graft occlusions, antithrombotic treatment should be continued for at least one year after coronary artery bypass graft surgery.

Adult↗
PubMed1990

Tricuspid valve endocarditis in the drug addict: a reconstructive approach ("vegetectomy").

This report describes the case of a 24-year-old female heroin addict with large tricuspid valve vegetation, recurrent septic pulmonary emboli, and renal failure, due to immune-complex nephritis. The clinical course was initially complicated by acute hepatitis A. Because of recurrent emboli and persistent fever despite adequate antibiotic therapy she underwent excision of the vegetation ("vegetectomy") and tricuspid valvuloplasty. She was well at follow-up 12 months later with trivial tricuspid regurgitation shown by doppler-echocardiography. Kidney and liver function were normal. Right-heart endocarditis in drug addiction and therapeutic approaches are discussed. In selected cases "vegetectomy" and valvuloplasty offer a promising therapeutic alternative.

Adult↗
PubMed1990

Heart valve replacement with the Björk-Shiley and St Jude Medical prostheses: a randomized comparison in 178 patients.

In 178 patients, a randomized prospective comparison between the 60 degrees spherical disc Björk-Shiley (BS) and the St Jude Medical (SJM) heart valve prostheses was performed. Four-week perioperative mortality was zero in the BS (n = 84) and 4.3% in the SJM group (n = 94). During a mean (+/- SD) follow-up of 52 +/- 20 months or 778 patient-years, late cardiac mortality per year was 2.4% in the BS and 2.2% in the SJM group. The yearly thromboembolic rates were 1.4% in the BS and 2.0% in the SJM group. There was no mechanical valve failure or haemolytic anaemia. Paravalvular leaks and major bleeding complications occurred at low rates in both groups (1.1% and 2.2% per year in BS; 0.7% and 1.7% per year in SJM). Functional results were similarly good with 96% of patients with BS valves and 95% of patients with SJM prostheses being in NYHA classes I and II, respectively. We conclude that heart valve replacement with mechanical prostheses can be performed with equally good results using either the Björk-Shiley spherical disc valve or the St Jude Medical bileaflet prosthesis.

Aged↗
PubMed1990

Different mobilization of calcium in endothelin-1-induced contractions in human arteries and veins: effects of calcium antagonists.

We studied the role of extra- and intracellular Ca2+ in endothelin-1-induced contractions of the isolated human internal mammary artery and vein. Veins were more sensitive to the peptide than arteries (concentration shift:3.2-fold; n = 4-10, p less than 0.05). The Ca2+ antagonists darodipine, verapamil, and diltiazem (10(-7)-10(-6) M) did not prevent the response to endothelin-1 in both vessels. In contrast, darodipine (10(-8)-10(-6) M), added after the contraction had developed, partially reversed the response in the artery (26 +/- 7%) and particularly in the vein (67 +/- 5%; n = 4, p less than 0.005 compared to the artery). Removal of extracellular Ca2+ reduced the contractions to endothelin-1 (10(-8) M) in the artery (control: 89 +/- 4% of 100 mM KCl; Ca2(+)-free: 68 +/- 4% n = 4-6, p less than 0.01), but not in the vein except at low concentrations (10(-9) M) of the peptide. After removal of intracellular Ca2+ with caffeine in the artery, endothelin-1 still evoked a contraction (17 +/- 3%, n = 3; p less than 0.005 vs. control), while in the vein the response was abolished. Thus, mobilization of Ca2+ during endothelin-1-induced contractions differs in the human internal mammary artery and vein. In the artery, the contraction depends on extracellular Ca2+, intracellular caffeine-sensitive Ca2+ stores, and a caffeine-insensitive component, while in veins, mobilization of intracellular Ca2+ is most important. Ca2+ antagonists do not prevent, but partially reverse, endothelin-1-induced contractions indicating that voltage-operated Ca2+ channels do not initiate but contribute to the maintenance of the response.

Caffeine↗
PubMed1990

Threshold concentrations of endothelin-1 potentiate contractions to norepinephrine and serotonin in human arteries. A new mechanism of vasospasm?

Endothelin-1 is an endothelium-derived vasoconstrictor peptide. Its circulating levels are below those known to evoke direct vascular effects. To study whether low concentrations of endothelin-1 potentiate the effects of other vasoconstrictor hormones, we suspended isolated human internal mammary and left anterior descending coronary artery rings in organ chambers for isometric tension recording. In mammary artery rings, the contractions to norepinephrine (3 x 10(-8) M) were potentiated by threshold (3 x 10(-10) M) and low concentrations (10(-9) M) of endothelin-1 (96 +/- 35% and 149 +/- 58% increase from control; p less than 0.01 and 0.001; n = 6). The inhibitor of endothelial nitric oxide formation L-NG-monomethyl arginine did not affect the potentiating effects of the peptide. The calcium antagonist darodipine (10(-7) M) prevented the potentiation of the response to norepinephrine evoked by endothelin-1. Similarly, contractions to serotonin (10(-7) or 3 x 10(-8) M) were amplified by endothelin-1 (3 x 10(-10) M) in the mammary (30 +/- 9%) and in the coronary arteries (59 +/- 25%). Endothelin-1 (10(-9) M) further potentiated the response (57 +/- 23% in mammary and 87 +/- 26% in coronary arteries; p less than 0.05; n = 7 and 3). The sensitivity of mammary arteries to calcium chloride was markedly enhanced in the presence of endothelin-1 (3 x 10(-10) M; concentration shift, eightfold; p less than 0.01; n = 5).(ABSTRACT TRUNCATED AT 250 WORDS)

Arteries↗
PubMed1990

Interaction between endothelin-1 and endothelium-derived relaxing factor in human arteries and veins.

Endothelin-1 is a 21-amino acid endothelial vasoconstrictor peptide that may be the physiological antagonist of endothelium-derived relaxing factor (EDRF). Endothelin-1 (10(-11)-3 x 10(-7) M) evoked potent contractions of isolated internal mammary arteries, internal mammary veins, and saphenous veins, which were enhanced in internal mammary veins as compared with internal mammary arteries (concentration shift, 6.3-fold; p less than 0.05) but not in the saphenous veins. Endothelial removal augmented the response to the peptide (at 3 x 10(-7) M) in internal mammary arteries (p less than 0.05) but not in veins. In the artery, EDRF released by acetylcholine or bradykinin reversed endothelin-1-induced contractions; in saphenous veins, both agonists were much less effective compared with the artery and veins contracted with norepinephrine (p less than 0.005-0.01). This inhibition of endothelium-dependent relaxations in veins occurred at half-maximal contractions but was most prominent at maximal contractions to the peptide. Nitric oxide similarly inhibited contractions to endothelin-1 and norepinephrine in internal mammary arteries, whereas in veins that were contracted with endothelin-1 but not with norepinephrine, the relaxations were blunted (p less than 0.005). The nitric oxide donor SIN-1 and sodium nitroprusside induced complete relaxations of internal mammary arteries but were less effective in veins contracted with endothelin-1 (p less than 0.005). Thus, in normal human arteries, EDRF inhibits endothelin-1-induced contractions, whereas the peptide specifically attenuates the effects of EDRF and nitrovasodilators in veins. This may be important in pathological conditions associated with increased levels of endothelin-1 and in veins used as coronary bypass grafts.

Acetylcholine↗
PubMed1990

[Diagnostic value of CK-MB for the determination of perioperative infarct in coronary artery bypass operation].

To assess the diagnostic value of CK-MB determinations after CABG surgery to detect or exclude perioperative myocardial infarction, 228 consecutive patients were studied with serial ECGs, as well as pre- and postoperative left heart catheterization and thallium-201-scintigraphy. CK-MB values above or below 100 U/l had a sensitivity and specificity of 73% each. There was a linear correlation between CK-MB values and total ischemic time. Thus, an increasing amount of myocardium is lost with each additional minute of ischemia despite today's methods of myocardial protection. Due to its low diagnostic accuracy CK-MB seems not to be very helpful for the diagnosis of perioperative myocardial infarction.

Adult↗
PubMed1989

[Pulmonary embolism--preventive measures with special reference to the cava filter].

Preventive measures for pulmonary embolism are prophylaxis of deep vein thrombosis and prevention of recurrence. This secondary prevention is mainly based on heparin therapy, but in the event of contraindications, complications or failure of this treatment, as well as in certain special situations, implantation of a vena caval filter is indicated. Indications and methods for inferior vena cava interruption are presented on the basis of a literature review and compared with personal experience of 24 patients. This demonstrates that the newer types of caval filters are easily implanted, disturb blood flow of the inferior vena cava only to a very small degree and are effective in preventing recurrence. Hence earlier reservations about the use of these devices are no longer justified.

Adolescent↗
PubMed1989

Trial of low-dose aspirin plus dipyridamole versus anticoagulants for prevention of aortocoronary vein graft occlusion.

In a prospective randomised trial, 249 patients who had aortocoronary vein bypass surgery were assigned either to a platelet inhibitory drug regimen or to standard anticoagulant therapy. Treatment was replaced by placebo in half of the patients in each group after 3 months. The platelet inhibitory drug regimen--very low-dose aspirin combined with dipyridamole--was as effective as standard anticoagulant therapy to prevent early and late graft occlusion. Death, myocardial infarction, and severe bleeding occurred significantly more often in patients receiving anticoagulants, whereas mild drug-related gastrointestinal and cerebral side-effects were more common in patients taking platelet inhibitory drugs. Antithrombotic treatment should be continued for at least 1 year after coronary artery bypass graft surgery.

4-Hydroxycoumarins↗
PubMed1989

[The treatment of an embolized central venous catheter].

The frequent use of central venous catheters for pressure monitoring or long-term administration of fluids can in rare cases lead to embolization of catheter fragments. In view of the potential complications, extractions, extraction is mandatory. The fragments may be removed by use of a loop snare, a helical basket or a myocardial biopsy catheter. The specific approach is described.

Catheterization, Central Venous↗
PubMed1989

Sudden cardiac death after aortic valve surgery: incidence and concomitant factors.

A retrospective analysis of 599 consecutive patients after aortic valve surgery aged 7-82 years (mean 56) was performed. During a follow-up of 1-14 years (mean 4.7 years) a 4-week perioperative mortality of 6.9% and a late annual mortality of 3.6% were observed. Sudden cardiac death was the most frequent single cause of death, accounting for 24% of all deaths. Patients dying suddenly were younger than patients dying from other causes (51 +/- 17 vs. 59 +/- 14 years, p less than 0.05) and showed more left ventricular hypertrophy by electrocardiographic criteria when compared with matched survivors (mean Estes score 5.2 +/- 2.4 vs. 2.8 +/- 1.9; p less than 0.01) and with patients dying nonsuddenly (mean Estes score 5.2 +/- 2.4 vs. 1.8 +/- 1.8; p less than 0.01). Ventricular premature beats in the resting electrocardiogram were more prevalent in patients dying suddenly than in matched survivors (55 vs. 20%; p less than 0.025) as well as in patients dying from other causes (55 vs. 25%; p less than 0.05). In addition, there were more intracardiac conduction disturbances and more ungrafted coronary vessels with insignificant stenoses at the time of surgery in sudden death patients. Our findings suggest that after aortic valve replacement patients with left ventricular hypertrophy, bundle-branch block, and ventricular premature beats in the resting electrocardiogram are at increased risk for sudden cardiac death. A possible etiological role of concomitant coronary artery disease must be considered.

Adolescent↗
PubMed1989

Endothelium-derived relaxing factor and protection against contractions induced by histamine and serotonin in the human internal mammary artery and in the saphenous vein.

We investigated the release of endothelium-derived relaxing factor (EDRF) in response to serotonin and histamine in the human internal mammary artery and saphenous vein. The arteries and veins were obtained intraoperatively and were suspended in organ chambers to record isometric tension. In mammary arteries, histamine (10(-8) to 3 X 10(-6) M) induced relaxations in rings with (70 +/- 5%, IC50, 6.5 +/- 0.2) but not without endothelium (p less than 0.005 for rings with compared with those without endothelium, n = 7-10). The response was inhibited by methylene blue or hemoglobin, but not meclofenamate, and, therefore, EDRF was delineated as the mediator. Because chlorpheniramine but not cimetidine inhibited the response, EDRF was released by the H1-histaminergic receptor (n = 5-8). In contrast, in saphenous veins, histamine caused only weak or absent endothelium-dependent relaxations, but contractions were enhanced in rings with endothelium (p less than 0.05, n = 6). Serotonin did not induce endothelium-dependent relaxations, but contractions were markedly greater in veins compared with arteries (p less than 0.005, n = 6). The endothelium inhibited the maximal contraction to serotonin in arteries (p less than 0.034) but not in veins. Thus, EDRF protects against contractions induced by histamine and serotonin in the mammary artery but not in the saphenous vein. This may be important for improved graft function and patency of the artery compared with that of the vein.

Endothelium, Vascular↗
PubMed1989

[After-care following heart and thoracic surgery].

The paper is directed towards those practitioners charged with the responsibility of delivering care pertinent to patients after cardiac valve replacement, coronary artery bypass grafting and surgery for lung cancer. In addition to the postpericardiotomy-syndrome the following complications associated with valve replacement are discussed: thrombotic occlusion or systemic thromboembolism, prosthetic valve endocarditis, mechanical valve dysfunction, postoperative arrhythmias. The patency of aorto-coronary bypass grafts decreases progressively over time and relates directly to improvement in symptoms and in myocardial function. Antiplatelet therapy or anticoagulants are effective in preventing graft occlusion early after operation. The goal of follow-up of patients with curative lung resection for bronchial carcinoma are early detection and treatment of recurrent cancer, metastases or second primary (metachronous carcinoma) tumor, functional cardiorespiratory decompensation and late postoperative complications. It is emphasized that the physician should not consider the patient "cured" once he has undergone cardiac valve replacement, coronary artery bypass grafting or lung resection, but rather should consider him to be the subject of meticulous long-term medical care.

Carcinoma, Bronchogenic↗