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Biomedical subjects

S Iversen

Publications and source records attributed to S Iversen.

At least 19 recordsLinked to original sources
PubMed1992

[Long-term follow-up of thrombolytic treatment of acute infarct in combination with acute and elective revascularization].

From March 1983 to June 1986 in 206 patients with acute transmural myocardial infarction, combined intravenous and intracoronary therapy with streptokinase was initiated. After intravenous thrombolysis and randomization in two groups we performed a coronary angiography with selective intracoronary lysis. Infarct related vessels still occluded after intracoronary streptokinase application were opened mechanically in group I. In group II we performed additionally a percutaneous transluminal coronary angioplasty (PTCA) after mechanical recanalisation (occluded vessels) or after thrombolysis (open vessels). In 85 of 87 cases in group II, PTCA could be performed in the acute phase. Elective PTCA was performed in 22 patients of group I (21%) and in nine patients of group II (9%). Up to five years after myocardial infarction, coronary artery bypass grafting (CABG) was necessary in 22 patients (21%) of group I and in 23 patients (22%) of group II. Within four weeks after infarction CABG was performed in 32% and 17% of group I and II respectively. The six-year survival rate was 78% in group I and 82% in group II. Taken all patients together, the six-year survival rate was significantly higher (p = 0.002) for those with early reperfusion (less than or equal to 3.5 h). The survival rates of CABG-patients, PTCA-patients and patients without reperfusion were 91%, 74% and 65% respectively. Streptokinase thrombolysis results, combined with acute or elective PTCA and/or coronary bypass surgery, in a high six-year survival rate after acute transmural myocardial infarction. This rate is about 20% higher than ten years ago.

Angioplasty, Balloon, Coronary↗
PubMed1992

[Pulmonary thrombendarterectomy in thromboembolic pulmonary hypertension. The indications and early results].

Pulmonary thrombendarterectomy was performed in 32 patients (14 men and 18 women; mean age 38 +/- 15 years) with thromboembolic pulmonary hypertension (New York Heart Association stage III: n = 22; stage IV: n = 10). The preoperative arterial pO2 averaged 59 +/- 11 mm Hg; pulmonary vascular resistance (PVR) and mean pressure (MPAP) were increased to 1,045 +/- 430 dyn.s.cm-5 and 53 +/- 12 mm Hg, respectively. The perioperative death rate was 22% (7 of 32). In the 25 survivors the pulmonary hypertension was reduced to a PVR of 194 +/- 75 dys.s.cm-5, MPAP of 28 +/- 6 mm Hg. Subsequent re-examination in 15 patients (NYHA stage I: n = 14, stage II: n = 1) after a mean of 17 +/- 5 months demonstrated an arterial pO2 averaging 92 +/- 6 mm Hg and, in 14 patients, echocardiographically normal right-ventricular volumes and function. The primary success was confirmed in eight patients by haemodynamic measurements. These data indicate that thrombendarterectomy can effectively treat the increased PVR in most patients at all stages of the disease.

Angiography, Digital Subtraction↗
PubMed1992

Sarcoma of the pulmonary artery: report of two cases and a review of the literature.

Primary tumours of the pulmonary arteries are rare neoplasms seldom diagnosed during the patient's life time. We report on two cases of pulmonary artery sarcomas diagnosed during life time of the respective patients in intra-operative frozen sections by histopathological examination. Case 1 was of a 55-year-old man with a fibrosarcoma originating from the main pulmonary trunk. Case 2 was of a 43-year-old woman with a malignant fibrous histiocytoma originating from the right pulmonary artery. In both patients a radical tumour resection under cardiopulmonary bypass was attempted. Both patients, however, had a local tumour recurrence and died 18 months (patient 1) and 6 months (patient 2) after surgery. A review of pulmonary artery sarcomas is given.

Adult↗
PubMed1992

Surgical treatment of myocardial bridging causing coronary artery obstruction.

Nine patients with obstruction of coronary artery blood flow caused by myocardial bridging underwent surgery after failure of medical treatment. The diagnoses were made angiographically at rest or during beta-stimulation. Impaired blood flow was found only in the left anterior descending artery in seven patients and additionally in the diagonal branch in two. The operations, performed with cardiopulmonary bypass consisted of complete dissection of the overlying myocardium. All patients survived the operation. Major intraoperative complications were accidental opening of the right ventricle in two patients. Postoperative scintigraphic and angiographic studies demonstrated restoration of coronary flow and myocardial perfusion without residual myocardial bridges under beta-stimulation. Surgical relief of myocardial ischemia due to systolic compression of intramyocardial coronary arteries can be accomplished with low operative risk and with excellent functional results.

Adult↗
PubMed1992

Efficacy of phosphodiesterase inhibitor enoximone in management of postcardiotomy cardiogenic shock.

The efficacy of the phosphodiesterase inhibitor enoximone for reversal of severe postcardiotomy low cardiac output syndrome was investigated in 13 cases of cardiogenic shock refractory to conventional treatment consisting of beta-adrenergic agonists (n = 13) combined with vasodilators (n = 7), and intra-aortic balloon counterpulsation (n = 5). Following a bolus of 1 mg/kg enoximone, cardiac and stroke volume indices increased from 1.56 +/- 0.27 l/min/m2 and 16.3 +/- 3.3 ml/m2, respectively, to 2.72 +/- 0.67 and 27.8 +/- 7.1 (both p < 0.001). Mean arterial pressure fell, from 77 +/- 11 to 68 +/- 9 mmHg (p < 0.05), as did atrial filling pressures (LAP and RAP), LAP from 21.3 +/- 5.5 to 15.9 +/- 2.9 and RAP from 16.6 +/- 2.3 to 13.7 +/- 2.1 mmHg (both p < 0.01). The heart rate rose by only 5%. Enoximone therapy was maintained by a continuous infusion (5-7.5 micrograms/kg/min) for 40.6 +/- 8.6 hours (range 14-92). All hemodynamic parameters remained stable throughout treatment. Six patients died of sepsis and/or multiorgan failure but seven were discharged from hospital. Enoximone thus improved hemodynamic performance significantly in cardiogenic shock after open-heart surgery. It also has proved valuable in cardiac failure when conventional therapy was unsuccessful.

Aged↗
PubMed1992

Reoperation and the centrifugal pump?

Postperfusion syndrome is still a problem in long cardiac operations using extracorporeal circulation (ECC). To evaluate whether or not centrifugal blood pumping during open heart surgery is beneficial, a randomized, prospective study was undertaken of 50 consecutive patients undergoing elective coronary artery bypass grafting. The patients were divided into two groups of 25 each. In group 1 a centrifugal pump (Biomedicus) was used as arterial blood pump, while in group 2 a roller pump (Stöckert) was used. The two groups did not differ significantly and the number of variables during surgery was kept low (identical perfusion set, two surgeons, minimal cardiotomy suction). The parameters studied included the cellular elements of the blood and components indicating their functional integrity, such as PMN-elastase, plasma hemoglobin, beta-thromboglobulin, and thrombin-antithrombin III complex and D-dimer as representatives for activated coagulation and secondary fibrinolysis. Blood and urine samples were taken every 15 min during ECC, on arrival in the intensive care unit, and 1, 3, 6, 12, and 24 h thereafter. No difference between the groups was found in regard to bypass time, ECC flow and volume, fluid balance, and clinical outcome. Significant differences in favor of group 1 were found in plasma hemoglobin (P less than 0.05), beta-thromboglobulin (P less than 0.01), D-dimer (P less than 0.05), and platelet counts (P less than 0.5). These differences were clearly ECC-time-dependent and became statistically significant after 90 min bypass. We conclude that roller pumps still can be safely used for standard cardiac procedures.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1992

[Diagnostic goals in aortic dissection. Value of transthoracic and transesophageal echocardiography].

The combination of different ultrasound techniques like transthoracic, suprasternal, subcostal and transesophageal echocardiography have a high sensitivity and specificity in the diagnosis of aortic dissection. The limitation of this combined ultrasound technique is related to the visualization of the ascending part of the aortic arch which, cause of the interposition of the trachea, can not be visualized completely. The beginning or the end of a dissection in this part of the aorta may be misinterpreted. False negative results are rare. False positive results due to artefacts resulting from reverberations in an ectatic ascending aorta have to be taken into account. The most important diagnostic aims in acute or chronic aortic dissection can be described: 1. confirmation of the diagnosis by visualization of the intima membrane, 2. the differentiation of the true and false lumen depending on visualization of spontaneous echocardiographic contrast thrombus formation, slow or reduced reversed flow, systolic diameter reduction and signs of entry jet into the false lumen, 3. detection of intimal tear, demonstrating communication by two-dimensional or color Doppler echocardiography, 4. determination of the extent of the dissection with classification according to DeBakey type I, II and III or Stanford A and B with differentiation to communicating or non-communicating dissection, antegrade or retrograde dissection limited to the descending aorta or expanding to the ascending aorta, 5. detection of wall motion abnormalities as a sign of preexisting coronary artery disease or myocardial ischemia due to ostium occlusion by an intimal flap, coronary artery rupture or collapse of the true lumen during diastole, 6. detection and grading of aortic insufficiency, 7. detection of side branch involvement by suprasternal, subcostal and abdominal sonography, which will gain the information which side can be chosen for cannulation or catheterization at the femoral artery, 8. detection of pericardial pleural effusion and mediastinal hematoma as a sign of emergency as rupture can occur within minutes. Without surgical intervention have be performed. Based on these informations, surgery can be performed in all acute situations in type A dissection without further investigations. This decision is particularly important in patients with signs of emergency like pericardial or pleural effusion or mediastinal hematoma.

Aortic Dissection↗
PubMed1992

Effects of tolazoline and prostacyclin on pulmonary hypertension in infants after cardiac surgery.

OBJECTIVE: To evaluate the hemodynamic effects of tolazoline and prostacyclin in infants with pulmonary vasospasm after cardiac surgery. DESIGN: Prospective cohort study. SETTING: Pediatric ICU. PATIENTS: The cohort consisted of 42 infants and children with congenital heart disease and pulmonary hypertension who underwent corrective surgery and were monitored postoperatively using pulmonary artery catheters. Fourteen infants (2 to 12 months old) in this group required postoperative treatment with tolazoline or prostacyclin. INTERVENTIONS: Tolazoline was administered as a bolus of 0.5 mg/kg for treatment of persistent pulmonary hypertension or acute pulmonary hypertensive crisis. If its effectiveness was proved after 30 mins by hemodynamic measurements, a continuous iv infusion of 0.5 mg/kg/hr was established. Higher doses of tolazoline were avoided. If tolazoline treatment did not fulfill the criteria for pulmonary vasodilation, prostacyclin was given by continuous iv infusion at a starting rate of 5 ng/kg/min, followed by 10 ng/kg/min. In three patients, the infusion rate was increased to 15 ng/kg/min. RESULTS: Bolus administration of tolazoline resulted in a distinct pulmonary vasodilation in seven infants: mean pulmonary artery pressure and pulmonary vascular resistance decreased by an average of 35% and 45%, respectively. In these patients, tolazoline was infused over the following 12 to 72 hrs. One infant who received tolazoline for 72 hrs developed a clinically important gastrointestinal hemorrhage. In seven nonresponders to tolazoline, prostacyclin (PGI2) at an infusion rate of 5 ng/kg/min led to pulmonary vasodilation in five patients, at an iv infusion rate of 10 ng/kg/min in all seven infants studied. The latter dose of PGI2 reduced the mean pulmonary artery pressure by an average of 37%, and pulmonary vascular resistance by 43%. Transient withdrawal of prostacyclin in five infants demonstrated its short half-life and clinical effectiveness. Apart from a facial flush, no side-effects were encountered using PGI2 as an infusion over durations ranging from 12 to 504 hrs. CONCLUSIONS: These data suggest that, if tolazoline in a relatively low dose proves to be inefficient, prostacyclin can still be used as a safe and effective drug for treatment of pulmonary vasospasm. Prostacyclin offers more than a pharmacologic alternative to increased tolazoline dosages.

Drug Evaluation↗
PubMed1991

[Chronic thromboembolic cor pulmonale in pacemaker-associated right atrial thrombi. Pulmonary thromboendarterectomy with removal of the electrodes as a life-saving measure].

Life-threatening chronic cor pulmonale occurred in a 22-year-old woman with congenital 3 degrees atrioventricular block, 6 years after implantation of a pacemaker and 3 1/2 years after removal of the pacemaker (the electrodes were too firmly attached to be removed). The emboli originated from the right-atrial thrombi which had formed around the electrodes left in situ. The embolic source shrank during systemic administration of urokinase, initially 600,000 IU in 60 min, then 100,000 IU per hour, and pulmonary perfusion improved transiently. Nonetheless the patient became breathless on the slightest physical exertion. Recurrent syncopal attacks with marked increase of pulmonary artery pressure necessitated pulmonary thrombendarterectomy and removal of the electrode and wires. Thereupon the patient's condition clearly improved so that 6 months postoperatively her exercise tolerance was again unimpaired.

Adult↗
PubMed1991

Evaluation of the healing of precoated vascular dacron prostheses.

Knitted and woven Dacron grafts commercially coated with bovine collagen, gelatin and human albumin were implanted end-to-side between the infrarenal aorta and the bifurcation in 35 growing pigs. Grafts were explanted after 4, 8 and 12 weeks and compared to 6 uncoated knitted prostheses preclotted with blood that served as a control. Uncoated grafts rapidly developed a firmly attached neointima lined with endothelium. Compared with coated grafts the thrombus-free area of uncoated grafts was significantly larger (P less than 0.05). The slow resorption of albumin resulted in a delayed and incomplete neointimal healing and failing graft incorporation. Although the bovine collagen was only minimally cross-linked by formaldehyde, healing of the neointima was compromised in a thin woven graft that demonstrated peeling of the inner capsule even after 12 weeks. The identical collagen as well as bovine gelatin were quickly degraded in knitted grafts and both types showed transprosthetic infiltration at 4 weeks. All knitted grafts coated with either collagen or gelatin, however, were occluded after 8 and 12 weeks. Light microscopy revealed hyperplasia of smooth-muscle cells within the thickened distal anastomotic region. These results demonstrate that a timely return of porosity is mandatory for the development and maintenance of an intact neointima. Both the structure of the fabric as well as the method of preparing the coating are crucial variables to determine the rate of biodegradation.

Animals↗
PubMed1991

PTCA of the left main stem following protective coronary artery bypass grafting.

Percutaneous transluminal coronary angioplasty (PTCA) was performed in 14 patients with significant left main stem stenosis following protective coronary artery bypass grafting (CABG). The procedure was successful in 13/14 patients (93%), achieving a decrease in mean diameter stenosis from 74% +/- 7% to 31% +/- 12% (P less than 0.01). Accordingly, the absolute stenosis diameter increased from 0.9 mm +/- 0.3 mm to 2.4 mm +/- 0.5 mm (P less than 0.01). Dissection of the left main stem artery and a transient significant fall of blood pressure each occurred in one patient. No other serious complications were noted. Eight of 13 patients (62%) with successful PTCA underwent control angiography. Restenosis had occurred in 3 of 8 patients (38%) with total occlusion of the left main stem in 1 patient. All bypass grafts were found to be patent at follow-up. Clinical evaluation in all 14 patients revealed no serious events (death, myocardial infarction, repeat revascularization procedure) during a mean follow-up period of 27 months (range 6-39 months). PTCA of the left main stem following CABG can be considered a relatively safe and effective procedure with a marked restenosis-rate but beyond that, an uncomplicated long-term follow-up.

Adult↗
PubMed1991

Resection of central primary pulmonary artery sarcoma.

Primary sarcomas of the pulmonary arteries are rare, and the diagnosis is in the majority of the reported cases established postmortem. Surgical resection of these centrally located tumors has been performed either by pneumonectomy and/or local tumor resection. We report on two patients with sarcomas of the central pulmonary arteries who underwent successful resection of the tumor and prosthetic replacement of the arteries under cardiopulmonary bypass. One patient required additional thromboendarterectomy of the right pulmonary artery branches because of secondary thrombus formation. As primary pulmonary artery sarcomas are refractory to both chemotherapy and radiation, surgical resection remains the only means of treatment. The prognosis depends entirely upon resectability, which, if necessary, should be performed with the aid of cardiopulmonary bypass. In this way, lung resection may be avoided.

Adult↗
PubMed1991

Healing parameters of a new albumin-coated knitted Dacron graft.

Knitted dacron grafts commercially coated with human albumin were implanted end-to-side between the infrarenal aorta and the bifurcation in 9 growing pigs. Uncoated knitted dacron grafts implanted in 6 pigs served as a control. Grafts were explanted after 4, 8, and 12 weeks and evaluated for neointimal healing, peeling of the inner and outer capsule, extent of neoendothelialization, absorption of the sealant, interstitial infiltration, and perigraft inflammation. Toxicological in-vitro analysis included the evaluation of residual aldehydes and plasticizers. In contrast to the uncoated knitted prosthesis, which rapidly developed a layered neointima with complete neoendothelialization, only islands of neointima were found in albumin-coated grafts after 4 weeks. The neointima remained incomplete at 8 and 12 weeks with scanning electron microscopic evidence of sharply demarcated endothelial areas. No transprosthetic bridging was detectable even after 12 weeks and peeling of the inner and outer capsule was easily provocable. These results outline that the cellular and connective infiltration of the prosthetic wall is compromised unless degradation of the sealant is completed within four weeks: the neointimal development is delayed and graft incorporation fails, leaving the outer capsule unattached.

Albumins↗
PubMed1991

[Angiographic and histologic findings in high frequency rotational ablation in coronary arteries in vitro].

High-frequency rotational angioplasty is a recently developed method for coronary angioplasty in the catheter laboratory. An elliptical burr tip (phi 1.25-2.0 mm) with embedded diamant chips (phi 40-50 microns) is rotated by a helical drive shaft at 150,000-180,000 rpm. The burr is advanced over a 0.009-inch coaxial guide wire. To show the effects of this approach in diseased and healthy vessels, which may be present before and behind a stenosis, 17 atherosclerotic coronary arteries of nine human hearts, and 18 normal coronary arteries of nine pig hearts were treated by this method in vitro. Standardized coronary angiography was performed before and after Rotablator treatment, followed by histological examination. From these data the burr-to-vessel-diameter ratio was calculated for each vessel segment and compared with the angiographical and histological outcome. Partial or complete removal of the circumference of the innermost vessel wall layers was observed regularly. The average removal of tissue in human coronary arteries was limited to the intimal layer and in the pig coronary arteries to the internal elastic membrane. In the pig coronary arteries no intimal tears or dissections occurred, in human coronary arteries tears could be seen frequently (13 of 17 vessels (76%)). Media tears were observed in 3 of 17 vessels; one (2%) media dissection could be demonstrated; no perforation occurred. Thus, the in vitro studies suggest that coronary rotational angioplasty has only a slight effect on the vessel segment next to a stenosis, regardless of the burr-to-vessel-diameter ratio.(ABSTRACT TRUNCATED AT 250 WORDS)

Angioplasty, Balloon, Coronary↗
PubMed1990

Current early results of pulmonary thromboendarterectomy for chronic pulmonary embolism.

Some patients with chronic pulmonary embolism causing severely symptomatic pulmonary hypertension have been managed by heart-lung transplantation with an associated hospital mortality of 24%. To allow comparison with pulmonary thromboendarterectomy (PTE), we have reviewed the hospital morbidity and mortality in 149 consecutive patients. From 1 October 1984 to 18 September 1989, these patients underwent PTE utilizing a standardized procedure consisting of median sternotomy, cardiopulmonary bypass, deep hypothermia and circulatory arrest for bilateral PTE in 91% (136/149) of the procedures with 7.4% (11/149) and 1.3% (2/149) undergoing right or left PTE, respectively. Ventilator dependency (greater than or equal to 5 days on respirator) occurred in 28.3% (41/146). Hospital mortality (death within 30 days or in hospital) was 11.4% (17/149). The most common causes of death were respiratory and multiorgan failure, 10 (59% of deaths) and acute pulmonary hemorrhage, 3 (17% of deaths). We conclude that PTE with an operative mortality of half that of heart-lung transplantation (11.4% vs. 24%) should be the procedure of choice for significantly symptomatic chronic pulmonary embolism. Furthermore, the hazards of immunosuppression and chronic graft rejection are avoided.

Adult↗