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Biomedical subjects

S Iversen

Publications and source records attributed to S Iversen.

At least 73 records · Page 4Linked to original sources
PubMed1989

Technique of pulmonary thromboendarterectomy for chronic pulmonary embolism.

Pulmonary embolism infrequently results in severe chronic pulmonary arterial obstruction. However, when it does, affected patients are significantly symptomatic and have shortened survival. Medical management has proven ineffective. In the majority of surgical reports, unilateral thoracotomy with distal pulmonary arteriotomies has been emphasized. The average operative mortality was 22%. In this article, we discuss various preoperative considerations and describe in detail a surgical approach using median sternotomy for bilateral pulmonary thromboendarterectomy with cardiopulmonary bypass, deep hypothermia and circulatory arrest. With this standardized approach in 103 consecutive patients from October 1, 1984, to September 20, 1988, the hospital mortality (death within 30 days or during hospitalization) has been 11.7%.

Cardiopulmonary Bypass↗
PubMed1989

Metabolic effect of islet B-cell function in insulin-treated diabetes.

We studied the relationship between endogenous insulin secretion and fasting levels of plasma free fatty acids (FFA), plasma acetoacetate plus plasma 3-hydroxybutyrate (total ketone bodies), blood glucose, and HbA1 in 132 diabetic outpatients treated with conventional insulin regimens. Patients were divided into four groups according to plasma C-peptide concentration after intravenous stimulation with glucagon: one group with C-peptide stimulation less than 0.06 nmol/l, one group with C-peptide stimulation 0.06- less than 0.32 nmol/l, one group with C-peptide stimulation 0.32- less than 0.60 nmol/l, and one group with C-peptide stimulation greater than 0.60 nmol/l. According to clinical criteria the prevalence of insulin-dependent diabetes mellitus was approximately 90% in patients with C-peptide stimulation less than 0.32 nmol/l, approximately 25% in patients with C-peptide stimulation from 0.32- less than 0.60 nmol/l, and approximately 10% in patients with C-peptide stimulation greater than 0.60 nmol/l. All metabolic variables were significantly higher in patients without detectable C-peptide in plasma when compared to values found in patients with C-peptide stimulation from 0.06- less than 0.32 nmol/l. These two patient groups also had similar peripheral plasma free insulin levels and were comparable according to age, sex, and body mass index.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1989

Urgent indications for surgery in primary or secondary cardiac neoplasm.

Ten patients underwent resection of primary or secondary cardiac tumor. Two-dimensional transthoracic echocardiography per se accurately located the endoluminal cardiac mass in nine patients, and transesophageal echocardiography demonstrated a right atrial tumor in the tenth case. The indications for urgent surgery included prior embolic events (3 cases), syncopal attacks (2) or echocardiographic evidence of a multilobulated mass (2 cases). The operative strategy was standardized for atrial tumors, but for malignant myocardial neoplasm both the anatomic site and the extent of tumor growth determined the surgical procedure. Histologic examination showed myxoma in seven cases, fibroma in one and metastases of malignant melanoma in two cases. The course after resection of endoluminal benign tumor was uneventful apart from transient atrial fibrillation in four cases. Follow-up echocardiography (after 4-28 months) showed no recurrent growth. In both cases of intracardiac metastases there was recurrence within 6 to 8 months after resection of the growth.

Adult↗
PubMed1989

Initial clinical experience with an endoluminal spiral prosthesis for treating complicated venous thrombosis and preventing pulmonary embolism.

Fourteen patients with complicated venous thrombosis or recurrent pulmonary embolism were treated by implantation of an endoluminal spiral prosthesis subsequent to balloon angioplasty, surgical thrombectomy or embolectomy, a combination of these, or, in 2 cases, no other treatment. The patients were divided into 2 groups, based on their primary diagnosis and the purpose of the prosthesis. Group I included 8 patients with extensive iliofemoral or caval thrombosis, caused by congenital caval stenosis (1 case) or extravascular compression or retraction (7 cases); 7 of these patients had had previous operations, and the remaining patient had undergone thrombolysis, which failed. The current treatment consisted of balloon angioplasty and surgical thrombectomy or embolectomy, and implantation of an endoluminal spiral stent to prevent elastic recoil of the vessel. In 4 cases, an arteriovenous fistula was constructed and was taken down 3 months later; in 1 additional patient, a bilateral arteriovenous fistula was created. Group II comprised 6 patients with recurrent pulmonary embolism (4 cases), massive pulmonary embolism (1 case), or paradoxical bilateral carotid artery embolism (1 case). Four of these patients underwent surgical thrombectomy or embolectomy, while 2 had no treatment other than filter implantation. All 6 underwent transluminal implantation of a helix caval filter (a modification of the endoluminal spiral stent). All but 1 implantation was accomplished by means of either a transfemoral or a transjugular cutdown; the remaining implantation was performed transatrially after a pulmonary embolectomy. The only device-related complication was a retroperitoneal hematoma in Group I, resulting from perforation of the inferior vena cava by the guidewire during device implantation. This complication necessitated an emergency laparotomy and takedown of the arteriovenous fistula, which resulted in rethrombosis of the left iliofemoral vein. The other 7 stented veins were patent at early phlebographic follow-up, as were all 5 of those studied later. One Group-I patient died 4 months after surgery, due to tumor progression and without signs of caval restenosis. Twelve months postoperatively, 1 Group-II patient died of urosepsis without a recurrence of pulmonary embolism. Four of the 6 Group-II patients were studied late postoperatively, and all of their stented vessels were patent. There was no operative mortality or postoperative embolism. On the basis of these results, we conclude that endoluminal stenting with an expandable spiral prosthesis is a promising method for remote venous reconstruction. Moreover, it appears that the modified stent, or helix caval filter, compares favorably with commercially available filters.

Journal Article↗
PubMed1989

Acute hemodynamic response to intravenous enoximone: an animal study and preliminary report in infants after cardiac surgery.

In light of previous studies in adults, we considered that enoximone could be useful in treating children with therapy-resistant cardiovascular insufficiency. Prior to clinical administration, we investigated the cardiovascular properties of enoximone in anesthetized and ventilated piglets characterized by small stroke volume and high heart rate. Enoximone was administered intravenously in increasing doses (0.25, 0.5, and 1 mg/kg). The animals were monitored with heart rate, systemic and pulmonary arterial pressures, and continuous electromagnetic flow. Enoximone induced a dose-dependent flow increase, whereby heart rate and systemic arterial pressure changed only slightly. With regard to persistent pulmonary hypertension in newborns, enoximone was also used in piglets to investigate the effects on endotoxin-induced, dopamine-resistant pulmonary hypertension. Enoximone (1 mg/kg i.v.) was given immediately after E. coli endotoxin (1.5 micrograms/kg i.v.) and inhibited the endotoxin-induced, eicosanoid-mediated pulmonary hypertension, whereas during infusion of dopamine (2 mg/kg/h), no drop in systemic blood pressure could be observed. In the clinical study, six infants with post-cardiac surgery low output syndrome despite maximal catecholamine inotropic support were given enoximone (i.v. bolus of 0.2, 0.5, or 1 mg/kg followed by continuous infusion of 7.5-10 micrograms/kg/min). Continuously measured mixed-venous oxygen saturation increased in a dose-related manner. Cardiac output increased significantly by 28%, accompanied by a decrease of arteriovenous oxygen content difference and O2 utilization ratio. The preliminary results show that intravenous enoximone produces acute useful hemodynamic effects in infants, in particular allowing a weaning of vasoactive amines.

Animals↗
PubMed1988

Improved diagnostic value of echocardiography in patients with infective endocarditis by transoesophageal approach. A prospective study.

In a prospective study, the clinical value of transoesophageal two-dimensional echocardiography (TOE) as compared with transthoracic two-dimensional echocardiography (TTE) was determined in patients with suspected infective endocarditis. Ninety-six patients were studied consecutively with an electronic sector scanner using 2.25 and 3.5 MHz probes for TTE and a 3.5 MHz probe embedded in tip of a flexible 12 mm gastroscope for TOE. Results of surgery and autopsy were available for 20 of the 96 patients with infective endocarditis and echocardiographically demonstrated vegetations and 70 control patients with valvular heart disease without infective endocarditis and no signs of vegetations, who were studied preoperatively with TTE and TOE. For TTE and TOE, the measured sensitivity was 63% and 100%, specificity 98% and 98%, positive predictive accuracy 92% and 95%, and negative predictive accuracy 91% and 100%, respectively. In 39 patients who had positive blood cultures, vegetations were found by TOE in 32 patients (82%), but in only 27 patients (69%) by TTE. Image quality was the main factor contributing to the superiority of TOE over TTE: it was reduced in 11/20 patients (55%) in whom vegetations were not detected by TTE. Another important factor was the size of vegetations. Only 6/24 vegetations (25%) of less than 5 mm but 9/13 vegetations of 6-10 mm, and 14/14 vegetations of greater than 11 mm detected by TOE were also observed with TTE. The clinical importance of detecting vegetations was demonstrated by the rate of embolism. In patients with vegetations embolism was 25% when blood cultures were positive and 21% when they were negative. In patients without echocardiographically detectable vegetations signs of embolism were seen in no patient with positive and 7% of the patients with negative blood cultures. Evidence of vegetations was found on the aortic valve in 14 patients and on the mitral valve in seven patients in whom valvular incompetence was not present, indicating that the valve had not yet been damaged significantly. TOE is superior to TTE in detecting vegetations in suspected infective endocarditis because of better image quality, particularly when vegetations are small. TOE seems to be indicated in patients with suspected endocarditis and reduced image quality or negative TTE results. Early detection of vegetations on valves may help confirm the diagnosis of infective endocarditis at an early stage and hopefully lead to an improved prognosis by reducing delay in instituting appropriate therapy.

Echocardiography↗
PubMed1987

[Assessment of heart valve reconstructive measures using intraoperative transesophageal contrast echocardiography].

In 30 patients (6 mitral stenoses, 13 mitral insufficiencies, 12 tricuspid insufficiencies) intraoperative transoesophageal contrast echocardiography (TEE) was performed to examine the valve function after AV valve reconstruction. In the beating heart 1 ml of contrast medium was injected into the ventricle to assess the success of valve reconstruction by the extent of regurgitation into the left or right atrium respectively. In all 12 patients successful tricuspid valve reconstruction was detected. In 16/19 cases with mitral valve repair successful reconstruction has been demonstrated. In another 3 patients severe mitral insufficiency after valve repair was detected by TEE, finally intraoperative decision for valve replacement was made.

Echocardiography↗
PubMed1987

Diagnosis of aortic dissection: the value of transesophageal echocardiography.

Using the transesophageal approach the descending part of the aorta can be imaged by two-dimensional enchocardiography in cross sections comparable to computer tomograms. The value of combined transesophageal and transthoracic echocardiography was evaluated in 53 patients who were studied consecutively from 1983 to 1986 with symptoms of aortic dissection and compared with computed tomography, angiography, surgery and/or autopsy. In all patients the transthoracic aorta could be visualized and the dissection could be classified according to DeBakey: in 9 of 29 patients (34%) type I dissection, in 4 (14%) type II dissection and in 16 (55%) type III dissection was found. Operation was carried out because of acute symptoms in 11 of the 29 patients, and 3 additional patients died before operation. In 24 patients aortic dissection could be ruled out. A sensitivity of 97% for transthoracic and transesophageal echocardiography, of 80% for computed tomography and of 78% for angiography was calculated. The specificity for echocardiography was 100%, for computed tomography 100% and for angiography 95%. The positive predictive accuracy for echocardiography and computed tomography was 100% and 95% for angiography. The negative predictive accuracy for echocardiography was 96%, for computed tomography 77% and for angiography 79%. In no patient was an aortic dissection found by computed tomography or angiography which was not detected by echocardiography. In 1 patient with a large ectasia of the aorta ascendens aortic dissection was overlooked as retrospective analysis demonstrated. Signs of aortic insufficiency and pericardial effusion were detected.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1987

Intraoperative evaluation of reconstruction of the atrioventricular valves by transesophageal echocardiography.

In a total of 30 operations the mitral valve was reconstructed in 18, the tricuspid valve in 11, and both AV-valves in one patient. The result of reconstruction was tested first in the open arrested heart by injection of crystalloid solution into the appropriate ventricle either through the reconstructed valve or one of the great arteries. Upon termination of cardiopulmonary bypass the valve function was examined in the beating heart by means of transesophageal contrast echocardiography (TEE). For visualization 0.5-1.0 cc of agitated Gelifundol was injected into the ventricle. In 22 patients open testing as well as echocardiographic visualization showed identical and good operative results. In 6 patients TEE revealed mild insufficiency, but no further surgery was done. In three patients with mitral valve repair, contrast-echocardiography showed severe insufficiency, which had not been detected during cardiac arrest. In these patients changes in the level of the subvalvular apparatus caused systolic dislocation of the leaflets and massive reflux. Because of these findings definive valve replacement was performed in the same operation. Intraoperative TEE is a simple, safe and reliable method für assessment of AV-valve repair, thereby motivating the surgeon towards valve preservation and improving the outcome of valve surgery.

Adult↗
PubMed1987

Prevention of supraventricular tachyarrhythmias post coronary artery bypass surgery.

In a randomized prospective study 32 patients received either alinidine or a placebo for the first five postoperative days after coronary bypass surgery. The purpose of the study was to investigate the prophylactic antiarrhythmic properties of alinidine on supraventricular tachyarrhythmias (svt), which occur with incidence after open heart surgery. There was no significant difference in pretherapeutical parameters between the two groups. Eleven out of sixteen control patients (69%) and none of the patients treated with alinidine had svt. All arrhythmias occurred in the first three postoperative days and required medical treatment. Even after alinidine was stopped, patients in this group did not experience arrhythmias. The mean systolic blood pressure in the treatment group was 113 +/- 13 mmHg, in the control group it was 119 +/- 16 mmHg. The mean heart rate tended to be lower in the alinidine group (82 +/- 12 beats min-1 91 +/- 21 beats min-1. In 1/16 patients the alinidine treatment was stopped due to marked hypotension (less than 90 mmHg) and bradycardia (less than beats min-1). Two other patients in this group had short periods of mild bradycardia (less than 60 beats min-1) which was tolerated well. Additional medical treatment was not needed. In this study prophylactic treatment with alinidine proved to be highly effective in preventing postoperative arrhythmias following myocardial revascularisation.

Anti-Arrhythmia Agents↗
PubMed1987

Detection of aortic dissection by transoesophageal echocardiography.

The diagnostic value of a combination of transoesophageal and transthoracic echocardiography was evaluated in 21 patients with dissection of the aorta. The results were compared with those of computed tomography, aortography, and with findings at operation or necropsy or both. Transthoracic echocardiography identified three of the four patients with type I dissection, two of the five patients with type II dissection, and one of the 12 patients with type III dissection. When transoesophageal echocardiography was used as well the degree of aortic dissection was identified correctly in all 21 patients. In one patient with type I and in eight patients with type III dissection spontaneous echocardiographic contrast with a mural thrombus within the false lumen could be detected. Computed tomography was unable to demonstrate an intimal flap in one of two patients studied with type I dissection, in two of three patients with type II dissection, and in one of nine patients with type III dissection. Aortography was negative in one of two patients studied with type I dissection, two of four patients with type II dissection, and in one of eight patients with type II dissection. The whole thoracic aorta can be imaged by a combination of transthoracic and transoesophageal echocardiography. The addition of transoesophageal echocardiography to transthoracic echocardiography improves the recognition of aortic dissection. Furthermore, this examination can be performed at the bedside and the findings can be used as a basis for treatment.

Adult↗
PubMed1987

[Intraoperative assessment of the reconstruction of atrioventricular valves using transesophageal echocardiography].

To obtain good results in cardiac valve reconstruction surgery it is necessary to assess intraoperatively the efficiency of mitral or tricuspid valve repair. In 15 patients (three with mitral stenosis, 12 with mitral insufficiency) the mitral valve, in eight patients the tricuspid valve and in two patients both av-valves were reconstructed individually by commissurotomy and/or annulorrhaphy. During cardiac arrest, the valves were tested by filling the left or right ventricle with saline solution. After weaning from the extra-corporeal-circulation (ECC) I-2 cm3 of agitated Gelifundol were injected into the ventricle and the amount of regurgitation of micro-bubbles into the atrium was assessed by intraoperative two-dimensional transesophageal echocardiography. In 20 patients, testing during cardiac arrest and contrast echocardiography showed identical and good results. In two patients, the efficiency of mitral or tricuspid reconstruction could be finally verified by transoesophageal echocardiography. In another patient who was operated because of HOCM and a severe mitral insufficiency, the Bigelow procedure was combined with mitral valve reconstruction. Intraoperative open testing showed a good functional result, but a remaining severe mitral insufficiency was detected by transesophageal contrast echocardiography. An intraoperative decision for valve replacement was made. Our results show that transesophageal contrast echocardiography is a simple and accurate method of assessing the efficiency of valve reconstruction procedures. In some cases it gives more information than testing during cardiac arrest.

Adult↗
PubMed1986

[Color Doppler echocardiography in emergency diagnosis of ventricular septal rupture after acute myocardial infarct].

A 58-year-old man developed a rupture of the interventricular septum after acute posterior myocardial infarction. The two-dimensional echocardiographic features of the ruptured interventricular septum included akinesia of posterior wall, hyperkinesia of the interventricular septum and anterior wall, inferior basal septum aneurysm and visualization of the ventricular septum defect. Injection of echocardiographic contrast (Gelatin solution) into the right atrium showed a small right-to-left shunt, injection into the left ventricle (during heart catheterization) demonstrated massive crossing of echocontrast similar to the results of cineventriculography of the left ventricle. By coloured Doppler-echocardiography the left-to-right shunt could directly be visualized, as well as a diastolic right-to-left shunt. By calculation of pressure gradient using adjusted continuous wave Doppler, estimation of right ventricular pressure was possible. The results demonstrated that colour Doppler in addition to two-dimensional echocardiography has an important diagnostic role in patients with complications of myocardial infarction.

Echocardiography↗
PubMed1986

[Combination of color Doppler and transesophageal echocardiography in emergency diagnosis of type I aortic dissections].

We report on the use of colour Doppler- and transesophageal echocardiography in 2 patients with acute type I aortic dissection according to DeBakey. Using transesophageal echocardiography we obtained information on the extension and the entry site of the dissection without interfering with respiration and external thorax configuration. Using colour Doppler we were able to differentiate between the true and false lumen in the thoracic and abdominal aorta due to characteristic phasic flow patterns. In one patient the site of the entry tear of the intimal flap was localized by this method. Furthermore, a noninvasive semiquantitative evaluation of accompanying aortic regurgitation was possible. Colour Doppler gives additional information in the emergency diagnosis of patients with aortic dissection.

Adult↗
PubMed1984

[Coronary heart disease. Surgical development in the last 10 years--status of possibilities in West Germany].

This article addresses both the operative facilities for coronary bypass surgery in the Federal Republic of Germany and the surgical progress made in this field during the past 10 years. Like in many other countries, there is a continuing critical discrepancy between the number of patients offered for treatment and those operated upon. The reasons for this lack of facilities is explained. Recent moves by the respective Ministries and the public insurance system, however, have raised the expectation that this problem will be eliminated by the end of the decade. Progress in coronary surgery which is well mirrored by our own experience has undergone substantial changes in regards to patients selection and surgical approaches used. There has been a sharp increase in emergency coronary surgery. The proportion of combined procedures on the coronary arteries and myocardium or peripheral vessels has risen to approximately 10 while the rate of reoperation has not yet exceeded 5%. Resection of left ventricular aneurysms has largely been limited to patients with additional coronary stenoses and/or ventricular tachycardia. Complete revascularization (3.2 peripheral coronary anastomoses per patient) has become the rule and circular sequential vein bypass the preferred method for achieving this aim. On the basis of our experience it may be prognosticated that mammary artery bypass and open endarterectomy also of the left coronary system will play an increasing role in the near future.

Angioplasty, Balloon↗