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Biomedical subjects

E Schroeder

Publications and source records attributed to E Schroeder.

At least 37 records · Page 2Linked to original sources
PubMed1995

Revascularization of the circumflex artery with the pedicled right internal thoracic artery: clinical functional and angiographic midterm results.

Retroaortic crossing of the pedicled right internal thoracic artery for revascularization of the circumflex artery used in combination with a pedicled left internal thoracic artery anastomosed to the left anterior descending artery and its branches is an attractive technique to achieve an extensive arterial revascularization of the left ventricle. However, there is a suspicion that pulling the right internal thoracic artery through the transverse sinus could compromise its blood flow capacity and patency. Between January 1990 and July 1994 this technique was applied in 256 patients (202 men, 54 women; average age 62 years, range 31 to 80 years). Sixty-one patients had two-vessel disease and 195 had three-vessel disease. Seventeen patients were undergoing a reoperation. Twenty-two had a left ventricular ejection fraction of 40% or less. Thirty had diabetes. Twenty-eight had morbid obesity. The right internal thoracic artery was directed to the circumflex artery (259 anastomoses) through the transverse sinus and the left internal thoracic artery was anastomosed to the left anterior descending artery and its branches (375 anastomoses) in all patients. The 195 patients with three-vessel disease received additional coronary artery bypass grafts to the right coronary artery (93 saphenous vein grafts, 89 free inferior epigastric artery grafts, 12 pedicled right gastroepiploic artery grafts). In total, the 256 patients received 833 distal anastomoses (average 3.2, maximum 5 per patient) and 634 distal anastomoses were internal thoracic artery anastomoses (average 2.4, maximum 4 per patient). Three patients died early and eight had a nonfatal myocardial infarction. Seven patients needed postoperative intraaortic balloon pump support. Six patients underwent early reoperation because of excessive bleeding. Sternal dehiscence occurred in four patients. One of these four patients died of the complication 10 months after the operation. No patient was lost to follow-up (average 33 months). During follow-up, two sudden deaths and six noncardiac deaths occurred. Two patients had a nonfatal myocardial infarction and 12 had recurrence of angina. There were no late reoperations. One patient underwent a successful percutaneous balloon angioplasty of a native left anterior descending artery. Seventy-four patients, enrolled in prospective angiographic studies, underwent a postoperative recatheterization (average 13.2 months, range 6 to 58 months). Seventy-three of the 74 right internal thoracic artery grafts were patent. In comparison, 74 of 74 of the left internal thoracic artery grafts (106/107 anastomoses) were patent. Maximal stress thallium-201 scintigraphy results, obtained in 25 of those patients, did not reveal ischemia in the area of the circumflex artery.(ABSTRACT TRUNCATED AT 400 WORDS)

Adult↗
PubMed1995

Coronary artery bypass grafting with the inferior epigastric artery. Midterm clinical and angiographic results.

Between December 1988 and September 1993, 157 patients (141 men, 16 women, average age 60.2 years, range 37 to 78 years) underwent a complete myocardial revascularization with 157 inferior epigastric artery grafts and 285 internal mammary artery grafts (281 in situ, 4 free grafts). A total of 543 distal arterial anastomoses (average 3.4, range two to five per patient) were constructed, 376 with the internal mammary artery and 167 with the inferior epigastric artery. The inferior epigastric artery grafts were anastomosed to two left anterior descending, 5 diagonal, 34 circumflex, and 126 right coronary arteries. The indications for the use of the inferior epigastric artery were the unavailability of conventional conduits in 56 patients and a favorable anatomy or a young age in 101 selected patients. The clinical follow-up averages 31.8 months (range 6 to 62 months). Four patients died early, and there were three perioperative nonfatal myocardial infarctions. Eight patients required early reoperation for thoracic bleeding (2) or drainage of an abdominal parietal collection (6). There were four late deaths (2 sudden deaths, 2 noncardiac causes) and one nonfatal myocardial infarction. Angina recurred in nine patients, of whom one required reoperation and three underwent successful percutaneous balloon angioplasty of a native coronary artery (2) or an old saphenous vein graft (1). An early recatheterization was obtained before discharge (average 11 days) in 135 patients: 132 of 135 inferior epigastric artery grafts were patent. Seventy-seven patients underwent a second angiographic restudy 6 to 43 months after the operation. Forty-four of the 48 inferior epigastric artery grafts restudied within the first postoperative year (average 8.5 months) were patent, but eight showed a diffuse narrowing. Twenty-eight of the 29 inferior epigastric artery grafts examined angiographically between 13 and 43 months (average 25 months) were open, and among those 29, 25 were widely patent, perfectly matching the receiving coronary artery. Most of the occluded or narrowed inferior epigastric artery grafts were grafted onto coronary arteries with mild stenosis at restudy. Five patients underwent a third angiographic reexamination up to 60 months after the operation (average 39 months). All five inferior epigastric artery grafts were widely patent. The early attrition rate of the inferior epigastric artery, as for any free arterial graft, is probably the result of both the loss of a true pedicle and the need for constructing an additional proximal anastomosis. The fact that the patency rate of the inferior epigastric artery graft seems to remain stable beyond 1 year could suggest a good durability in the future.

Abdominal Muscles↗
PubMed1995

Patterns of medication use in patients with heart failure: a report from the Registry of Studies of Left Ventricular Dysfunction (SOLVD).

To determine patterns of medication use based on clinical variables in patients with heart failure, we analyzed data from 5,999 patients participating in the Registry of Studies of Left Ventricular Dysfunction (SOLVD). The Registry comprised a broad spectrum of patients with heart failure, including some with predominantly diastolic dysfunction. Drug use was determined in a population cross-sectional manner at the time of identification (74% hospitalized). The median number of drugs per patient was four, with diuretics taken by 62%, digitalis by 45%, angiotensin-converting enzyme inhibitors (ACE-I) by 32%, calcium channel blockers by 36%, antiarrhythmics by 22%, and beta-blockers by 18%. Only 18% were on the combination of ACE-I, diuretic, and digitalis. Stratification for diagnosis, heart failure symptoms, and ejection fractions demonstrated that triple-drug therapy (digitalis, diuretic, and ACE-I) was common only in those with ejection fractions less than .20 and several signs or symptoms of heart failure. Older patients were taking diuretics frequently (73% of patients older than 70 years of age), and our European center used fewer drugs overall, while prescribing digitalis about half as frequently as North American clinics. These data serve as the baseline for analysis of evolving therapeutic practice in patients with heart failure.

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PubMed1994

Quantitative angiographic follow-up study of the free inferior epigastric coronary bypass graft.

BACKGROUND: Attempts to improve late results of bypass coronary surgery have focused on the use of arterial conduits because of the high attrition rate of venous grafts. METHODS AND RESULTS: In our institution, 150 patients received an inferior epigastric artery (EPIG) as a free bypass graft, anastomosed to the right coronary artery in 73% and to a marginal branch in 20% of cases. These patients were followed prospectively by qualitative and quantitative angiography. Angiographic studies were performed in 122 patients (81%) early after surgery (11 +/- 5 days), and in 72 cases, a late evaluation (11 +/- 6 months) was also obtained. Quantative angiography (basal and after isosorbide dinitrate [ISDN]) was performed on the in situ EPIG in a large subset of these patients, as well as in 59 patients before bypass surgery. The patency rate was 98% at early control and remained high (93%) at late control. However, at late control, 14 EPIGs were occluded or threadlike, but of these 14, eight were grafted on a coronary artery with a moderate stenosis (< or = 60%) and with good anterograde perfusion. Mean basal EPIG diameter increased from 2.23 +/- 0.42 mm before surgery to 2.57 +/- 0.52 mm at 11 days (P < .01) but decreased to 2.20 +/- 0.47 mm in late study (P < .01 versus 11 days and P = NS versus before surgery). Vasodilation of EPIG with ISDN was observed before surgery (+0.34 +/- 0.20 mm, P < .001) and at late control (+0.20 +/- 0.17 mm, P < .001) but not in the early postoperative period for the whole group. Early after surgery, basal diameter was not different from native EPIG dimensions after ISDN (2.57 +/- 0.52 versus 2.56 +/- 0.39 mm), suggesting maximal dilation. However, vasodilation with ISDN was observed in a subgroup of patients at this time. These responder patients (n = 51) had a smaller basal diameter (2.47 +/- 0.49 versus 2.67 +/- 0.54 mm, P < .05) and a smaller runoff (P < .001) than nonresponder patients. CONCLUSIONS: EPIG grafts have a good early patency rate. The mid-term patency rate remains high and seems to depend, at least partially, on flow through the native coronary artery. EPIGs initially increase their lumen size, probably to meet the increased blood flow due to myocardial requirements. Over time, EPIG diameters decrease mainly as a result of a higher basal vasomotor tone. Long-term angiographic follow-up (eg, 5 to 10 years) is needed to assess late patency rate and the relation with these early findings and will define the place of this new coronary bypass conduit.

Abdominal Muscles↗
PubMed1993

Resistance of the atherosclerotic plaque during coronary angioplasty: a multivariate analysis of clinical and angiographic variables.

The atherosclerotic lesion resistance to balloon inflation was assessed prospectively in 200 patients undergoing primary single-site balloon percutaneous transluminal coronary angioplasty (PTCA) by using an identical inflation protocol. This resistance was evaluated by the stenosis resolution pressure, which is the pressure at which the lesion mark is no longer visible on the inflated balloon. The stenosis resolution pressure distribution was normal with a mean value of 4.4 +/- 2.3 atmospheres. Multivariate analysis revealed 4 factors related to the stenosis resolution pressure: stable angina pectoris (p < 10(-6)), the presence of calcifications (p = 0.016), the occurrence of vessel wall dissection after balloon angioplasty (p = 0.005), and the absence of a branch arising in the middle of the stenosis (p = 0.047). It is concluded that the mechanical resistance of the coronary lesion is related to the anginal status, the presence of calcifications, and the occurrence of vessel wall dissection after balloon angioplasty, probably on the basis of the plaque composition.

Angina Pectoris↗
PubMed1993

Histomorphological evaluation of wound healing of rabbit oviduct after microsurgical reanastomosis with the use of autologous fibrin adhesive, human fibrin adhesive or poly-glycolic acid suture.

The morphology of the healing process of microsurgical reanastomosis of the rabbit oviduct with the use of fibrin adhesive, autologous and heterologous, and conventional sutures is described. Both oviducts in 48 rabbits were cut and reanastomosis were performed. The rabbits were killed at different intervals after the operations, ranging from 2 h to 28 days, and the anastomoses were evaluated by histomorphological examination. The autologous fibrin adhesive was absorbed after a week and an uncomplicated healing was observed. Heterologous fibrin adhesive caused a granulomatous inflammation interpreted as an immune reaction of the host to the foreign protein, and conventional suturing resulted in severe tissue damage with an intensive inflammatory reaction.

Animals↗
PubMed1993

Evaluation of ketanserin in the prevention of restenosis after percutaneous transluminal coronary angioplasty. A multicenter randomized double-blind placebo-controlled trial.

BACKGROUND: Ketanserin is a serotonin S2-receptor antagonist that inhibits the platelet activation and vasoconstriction induced by serotonin and also inhibits the mitogenic effect of serotonin on vascular smooth muscle cells. METHODS AND RESULTS: We conducted a randomized, double blind, placebo-controlled trial to assess the effect of ketanserin in restenosis prevention after percutaneous transluminal coronary angioplasty (PTCA). Patients received either ketanserin (loading dose, 40 mg 1 hour before PTCA; maintenance dose, 40 mg bid for 6 months) or matched placebo. In addition, all patients received aspirin for 6 months. Coronary angiograms before PTCA, after PTCA, and at 6 months were quantitatively analyzed. Six hundred fifty-eight patients were entered into the intention-to-treat analysis. The primary clinical end point of the study was the occurrence between PTCA and 6 months of any one of the following: cardiac death, myocardial infarction, the need for repeat angioplasty, or bypass surgery. It also included the need for revascularization actuated by findings at 6-month follow-up angiography. The primary clinical end point was reached by 92 (28%) patients in the ketanserin group and 104 (32%) in the placebo group (RR, 0.89; 95% CI, 0.70, 1.13; P = .38). Quantitative angiography after PTCA and at follow-up was available in 592 patients (ketanserin, 287; control, 305). The mean difference in minimal lumen diameter between post-PTCA and follow-up angiogram (primary angiographic end point) was 0.27 +/- 0.49 mm in the ketanserin group and 0.24 +/- 0.52 mm in the control group (difference, 0.03 mm; 95% CI, -0.05, 0.11; P = .50). CONCLUSIONS: Ketanserin at the dose administered in this trial failed to reduce the loss in minimal lumen diameter during follow-up after PTCA and did not significantly improve the clinical outcome.

Adult↗
PubMed1992

Right internal mammary artery extended with an inferior epigastric artery for circumflex and right coronary bypass.

The right in situ internal mammary artery extended end to end with a free inferior epigastric artery was used through the transverse sinus for sequential grafting to one marginal branch of the circumflex artery and one or both distal branches of the right coronary artery. This procedure was applied in 5 patients with three-vessel disease who received in addition a left in situ internal mammary artery as a sequential graft to the left anterior descending coronary artery and one of its diagonal branches. The postoperative course was uneventful in all cases. A postoperative coronary angiogram obtained on day 10 in 4 patients showed all the grafts and anastomoses patent.

Abdominal Muscles↗
PubMed1992

Use of the inferior epigastric artery for coronary bypass.

Between December 1988 and April 1991, 74 free inferior epigastric arteries were used in 73 patients for coronary artery bypass grafts. In addition, 72 of the patients received a left internal mammary artery for single or sequential grafting to the left anterior descending system and 62 a right internal mammary artery to the circumflex or the right coronary artery. Twenty-seven patients had no saphenous vein available, and two had no suitable internal mammary artery; in an attempt to make a complete arterial revascularization, we chose the inferior epigastric artery as an alternative conduit in 24 young patients and in 10 reoperations; bilateral internal mammary artery dissection was avoided in four patients with impaired lung function and in six patients with selected two-vessel disease to spare one internal mammary artery. The technique for harvesting the inferior epigastric artery is described. Fifty-three inferior epigastric artery grafts were anastomosed to the distal right coronary artery or to its branches, 18 to the distal obtuse marginals of the circumflex artery (three as sequential grafts and one as a natural Y graft), and three to the left anterior descending system. The mean number of distal anastomoses is 3.60 per patient. Seventy proximal anastomoses of the inferior epigastric artery were made to the aorta and four to one internal mammary artery. There were four early deaths and one nonfatal myocardial infarction. Four abdominal wound hematomas needed surgical drainage. Sixty-one patients underwent angiographic study on postoperative day 10:59 of 61 inferior epigastric artery grafts (63 of 65 inferior epigastric artery distal anatomoses) and 111 of 111 internal mammary artery grafts (155 of 156 internal mammary artery distal anastomoses) were patent. Clinical follow-up of all the survivors (100% follow-up) could be obtained with a mean period of 9 months (1 to 28 months). There was no late cardiac death, no infarction, and all the patients were free of angina. Nineteen patients underwent a 6-month postoperative angiographic study. Seventeen of 19 inferior epigastric artery grafts were patent and 16 of 19 were intact; 34 of 34 internal mammary artery grafts (46 of 47 internal mammary artery distal anastomoses) were patent and intact. In conclusion, free inferior epigastric artery grafts can reach the diaphragmatic ischemic areas of the heart. The early patency rate and the clinical results are encouraging but only long-term evolution and evaluation can determine the true efficacy of the inferior epigastric artery graft as a reliable conduit for coronary artery bypass graft operations.

Abdominal Muscles↗
PubMed1991

Influence of balloon size and stenosis morphology on immediate and delayed elastic recoil after percutaneous transluminal coronary angioplasty.

After successful coronary angioplasty, the minimal luminal diameter of the dilated coronary artery segment is generally smaller than the diameter of the largest balloon catheter at the maximal inflation pressure. The determinants of this phenomenon were studied in 28 patients. Biplane angiograms were obtained after intracoronary administration of isosorbide dinitrate (1 mg) before, immediately and 24 h after coronary angioplasty. Balloon and coronary luminal diameters were measured by automated contour detection. Immediately after the procedure, the difference between inflated balloon diameter and minimal luminal diameter averaged 0.93 +/- 0.43 mm for the entire group and was greater both in eccentric stenoses (1.13 +/- 0.39 vs. 0.70 +/- 0.36 mm; p less than 0.01) and after angioplasty with an oversized balloon (1.20 +/- 0.37 vs. 0.71 +/- 0.33 mm; p less than 0.005). At 24 h, the balloon - minimal luminal diameter difference was unchanged at the group level (0.86 +/- 0.38 mm, but the minimal luminal diameter increased significantly in the subgroup of coronary segments dilated with an oversized balloon (1.97 +/- 0.37 vs. 1.81 +/- 0.28 mm; p less than 0.05). Thus, the difference between the minimal diameter of a dilated coronary segment immediately after a successful coronary balloon angioplasty procedure and the maximal diameter of the inflated balloon catheter is dependent both on eccentricity of the stenosis and on the balloon/artery diameter ratio. Moreover, the increase in minimal luminal diameter 24 h after angioplasty performed with an oversized balloon suggest that in addition to elastic recoil partly reversible factors related to vessel barotrauma are involved.

Angioplasty, Balloon, Coronary↗
PubMed1991

Atrial natriuretic factor during percutaneous transluminal coronary angioplasty.

To study the release of plasma atrial natriuretic factor (ANF) and to explain the mechanism underlying its increase during myocardial ischemia, we measured plasma ANF and mean pulmonary capillary wedge pressure (PCW) before, during and after percutaneous transluminal coronary angioplasty (PTCA) in eight patients. All patients were free of calcium channel antagonists and beta-blocking drugs. Evidence of myocardial ischemia was observed in all patients with an increase of PCW from 3.2 +/- 1.2 to 10.6 +/- 2.9 mm Hg (mean +/- SD; p less than 0.001). Heart rate and mean blood pressure did not change significantly. We observed an increase of plasma ANF during PTCA, from 53 +/- 24 to 100 +/- 37 pmol/L (mean +/- SD; p less than 0.005). There was a correlation between absolute values of ANF and PCW before and during PTCA (r = 0.64, p less than 0.01). After PTCA, ANF levels remained increased for at least twenty minutes (p less than 0.005 vs basal state) despite a decrease in PCW. Thus, increase of PCW during this very short-term left ventricular ischemic dysfunction induces an increase of plasma ANF, which persists during a certain time when PCW returns to normal.

Aged↗
PubMed1991

Flow-induced vasomotor response to tachycardia of the human internal mammary artery and saphenous vein grafts late following bypass surgery.

Increasing blood flow results in endothelium-dependent vasodilation of angiographically normal epicardial coronary arteries in humans. To compare the ability of internal mammary artery (IMA) and saphenous vein (SV) used as coronary artery bypass grafts to adapt their vasomotor tone to an increase in myocardial blood flow demand induced by tachycardia, 10 IMA and seven SV grafts were studied by quantitative angiography more than 6 months (range, 6-82 months) after surgery in 17 patients. All grafts were angiographically smooth and implanted to large nonakinetic perfusion zones. Angiograms were obtained in basal sinus rhythm (71 +/- 10 beats/min), during atrial pacing (129 +/- 9 beats/min), and after intragraft infusion of 1 mg isosorbide dinitrate (ISDN). In basal sinus rhythm, the cross-sectional area of SV was superior to that of IMA (10.7 +/- 3.6 versus 5.4 +/- 1.7 mm2; p less than 0.01). All IMA dilated during pacing (+14.8 +/- 11.5%; p less than 0.005) and a further increase in IMA cross-sectional area occurred after ISDN (+27.4 +/- 20.1% versus basal; p less than 0.005). In contrast, SV failed to dilate during pacing (+0.3 +/- 5.4%; p = NS) and after ISDN (+0.7 +/- 6.0% versus basal; p = NS). Thus, an increase in myocardial blood flow demand induced by tachycardia results in dilation of IMA but not of SV grafted on coronary vessels. The ability of the endothelium to modulate the vasomotor tone of IMA grafts in response to changes in blood flow could contribute to their excellent long-term functional results after coronary artery bypass surgery.

Adaptation, Physiological↗
PubMed1990

Derivation of the nucleoproteins (NP) of influenza A viruses isolated from marine mammals.

The nucleoprotein (NP) genes of influenza viruses were sequenced from a variety of virus isolates derived from marine mammals: whales from the Pacific and Atlantic oceans, seal and gull from the Western Atlantic, and a tern from the Caspian Sea. In comparison to published NP sequences, we found pairs of NPs derived from avian and marine mammal isolates to be closely related, e.g., the gull-whale and mallard-seal pairs from the Atlantic Coast of the USA and the tern-Pacific Ocean whale pair of the Eastern Hemisphere. Our analysis suggests that influenza viruses have been independently introduced into marine mammals from avian sources for each of our three examples. Furthermore, the closeness of the relationship in these avian-mammalian NP pairs indicates that the introductions are relatively recent. The sequences of these marine mammal NPs are avian-like and can be clearly distinguished from human NPs. Our results provide further support of interspecies transmission of influenza A viruses from the avian host reservoir directly to mammalian hosts.

Amino Acid Sequence↗
PubMed1990

Autologous fibrin sealant in reconstructive rabbit oviduct microsurgery.

A simple method for preparing concentrated fibrinogen for use in a tissue adhesive system is described. Approximately 75% to 80% of the plasma fibrinogen can be separated and concentrated within 45 to 60 minutes from a small blood sample collected from the patient before the operation. Autologous fibrinogen prepared by this method was evaluated in reconstructive microsurgery of the rabbit oviduct.

Animals↗
PubMed1990

Effect of different body-exercise modes on the rate response of the temperature-controlled pacemaker Nova MR.

In order to evaluate the effect of different modes of physical exercise on the rate response of the temperature-controlled Nova MR, parameters such as temperature behaviour and correlation of work load to pacing rate were investigated using different types and protocols of stress testing. This study considered 21 patients (age: 66 +/- 12 y). The indications for the Nova MR were AV block (n: 14) and sick sinus syndrome (n: 7). The patients performed two different types of exercise (treadmill n: 13, bicycle n: 14) based on different protocols. We registered the surface ECG, pacing rate, exercise time, and (via data transmission by the RX 2000 programmer) blood temperature and pacing rate. An adequate rate response could be achieved with all the different types of exercise and protocols using more sensitive program settings. The type of stress testing used to adjust or evaluate the Nova MR seems to be secondary, although cycling as compared with treadmill exercise resulted in a slightly weakened reaction of temperature and pacing rate. Our investigations revealed a good correlation between work load and pacing rate independent of the type of stress testing. The initial DIP (48%) is not a constant phenomenon and showed inter- and intraindividual variations. Impressive psychological influences also exhibited an effect on temperature and pacing rate, sometimes preventing a DIP response. During exercise at lower work loads (under 50 watts, shorter than 3-4 min) the rate response of the Nova MR--without any detected DIP--is often delayed due either to a decrease or to a late and flat increase in temperature. An additional fast-reacting sensor could be advantageous in triggering the initial rate response in such cases.

Aged↗