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Biomedical subjects

D M Behrendt

Publications and source records attributed to D M Behrendt.

At least 37 records · Page 2Linked to original sources
PubMed1990

Cardiovascular surgery prophylaxis. A randomized, controlled comparison of cefazolin and cefuroxime.

A prospective double-blind trial was performed at a tertiary care center to evaluate perioperative cephalosporin prophylaxis in cardiac operations. Patients were randomized to receive either cefazolin (n = 104) or cefuroxime (n = 109), the preoperative dose being given within 1 hour before the initial incision. Drugs were continued for 48 hours (cefazolin, 1 gm intravenously every 8 hours; cefuroxime, 1.5 gm intravenously every 12 hours). Postoperative infections were assessed by trained nurse clinicians, and data were analyzed by the intention-to-treat principle. Sternal wound infections or mediastinitis occurred in one of 104 patients treated with cefazolin and 10 of 109 treated with cefuroxime (p = 0.01). Deep sternal wounds (including mediastinitis and sternal osteomyelitis) occurred in none of the cefazolin-treated patients and five cefuroxime-treated patients (p = 0.06). Although overall nosocomial infection rates were similar (16.3 versus 19.3 per 100), wound infection occurred somewhat more frequently with streptococci (groups B and D) in patients receiving cefazolin (four versus zero, p = 0.110); conversely staphylococcal infections were more frequent in the cefuroxime group (seven versus one, p = 0.066). Mean and median postoperative stay was 1 day shorter in the cefazolin group. In contrast to findings of a previous report, our data indicate that cefazolin prevented more sternal wound infections than cefuroxime, a finding that supports prophylaxis with a first-generation cephalosporin.

Adult↗
PubMed1989

Increased frequency of posttransplant lymphomas in patients treated with cyclosporine, azathioprine, and prednisone.

We have documented seven B cell lymphomas over a six-month period in 132 (5.3%) kidney and heart allograft recipients immunosuppressed with cyclosporine, azathioprine, and prednisone (triple therapy). This is a significant increase (P less than 0.0001) over the number of such tumors seen by us previously. Only 2 lymphomas had occurred in 669 cadaver and 29 living-related kidney allografts treated with azathioprine and prednisone alone (0.3%). In 160 cadaver kidney recipients treated with cyclosporine and prednisone there have been no lymphomas. Similarly in 14 living-related kidney recipients who were transplanted since the introduction of triple therapy for cadaver grafts, but continued to receive only azathioprine and prednisone, no lymphomas occurred. There seemed to be a clear relationship between this increase and the use of triple therapy. This led us to examine other possible contributing factors. A case control study has not shown any other factor that differs in patients in whom lymphomas developed. We have only been able to demonstrate Epstein Barr virus nuclear antigen in the cells of one tumor. Four of these 7 tumors were monoclonal, one polyclonal, and two indeterminate. All patients had their immunosuppression withdrawn and six received intravenous acyclovir. Three patients have shown some response but four patients died. Triple therapy is being used by many centers to reduce the level of cyclosporine toxicity. We wish to sound a note of caution that this may result in an increased incidence of posttransplant lymphomas.

Adult↗
PubMed1988

Surgical management of children and young adults with the Wolff-Parkinson-White syndrome.

The Wolff-Parkinson-White syndrome, as originally described, includes palpitations, tachycardia, and an abnormal electrocardiogram (short PR interval and wide QRS complex). The clinical manifestations are dependent upon a reentrant tachycardia supported by an accessory connection bridging the atrioventricular junction and frequently appear during the first two decades of life. Palpitations are the usual symptoms; less frequently, severe symptoms, such as syncope and sudden death, may result from very rapid atrioventricular conduction across the accessory connection during atrial fibrillation. We report the surgical management of 30 young patients with this syndrome, including 6 with life-threatening tachycardia. Surgical interruption of the accessory connection(s) was curative in 90% (27/30) of the patients; life-threatening symptoms were eliminated in the other three. Based on the limited knowledge of the natural history of the Wolff-Parkinson-White syndrome, the individual patient symptoms, and the electrophysiologic properties of each patient's accessory pathway(s), an algorithm is presented outlining the treatment options. This experience strongly suggests that surgical treatment of the Wolff-Parkinson-White syndrome is safe, effective, and possibly the preferred treatment for this disorder in selected young symptomatic patients.

Adult↗
PubMed1988

A reversible pulmonary artery band: preliminary experience.

Pulmonary artery banding has become an infrequently used surgical technique. However, if a band was developed that could be relieved without the need for open heart surgery, it is likely that pulmonary artery banding would be used more frequently in the management of infants with congenital heart disease. Such a pulmonary artery band was placed in seven 1 week old mongrel puppies by using a loop of an absorbable suture material (Vicryl). One dog died at 2 months as a result of right ventricular failure. The remaining six dogs underwent cardiac catheterization and pulmonary balloon angioplasty at 6 months of age. After measuring pulmonary artery, right ventricular and aortic pressures and performing a right ventricular angiogram, balloon angioplasty of the band site was performed. A 20 mm balloon angioplasty catheter (Medi-Tech) was used in all dogs. Balloon angioplasty decreased right ventricular pressure from 101 +/- 19 to 42 +/- 3 mm Hg (p less than 0.05) and right ventricular systolic outflow tract gradient from 59 +/- 14 to 7 +/- 2 mm Hg (p less than 0.03), and increased the size of the band site from 8.7 +/- 0.03 to 14.9 +/- 0.5 mm (p less than 0.01). All dogs were recatheterized 2 months after angioplasty and were then killed for pathologic evaluation. At follow-up catheterization, right ventricular pressure, right ventricular outflow tract gradient and pulmonary artery size at the band site remained at the values obtained immediately after angioplasty. Postmortem examination demonstrated that there was no evidence of pulmonary artery damage. Although these studies are preliminary, they suggest that a reversible pulmonary artery band can be performed.

Angioplasty, Balloon↗
PubMed1988

Magnetic resonance imaging of mediastinal paraganglioma.

The magnetic resonance (MR) findings are presented of a nonfunctioning mediastinal paraganglioma on both T1- and T2-weighted magnetic resonance images. The MR characteristics of this tumor differentiate it from previously reported functioning mediastinal paragangliomas (pheochromocytoma) and from other benign mediastinal neoplasms, although mediastinal bronchogenic carcinoma may produce a similar appearance.

Adult↗
PubMed1988

Repair of interrupted aortic arch in infancy.

Twenty-one patients undergoing repair of interrupted aortic arch between December of 1979 and January of 1987 were reviewed to determine the cause(s) of late morbidity and mortality. Ten underwent staged repair, and 11 had complete repair including all coexisting defects at the initial operation. Sixty-two percent are alive and clinically well 6 months to 6 years after the initial operation. Among the five patients who died late postoperatively, four had severe left ventricular outflow tract obstruction. Two other patients have had surgical relief of severe subaortic stenosis. In addition, significant recurrent or residual coarctation was found in four patients; it was relieved by balloon angioplasty in two patients, and two had surgical repair. None of the most recent seven patients, however, have had a residual ascending-descending aortic gradient. Careful follow-up for the detection of previously masked or newly developed left ventricular outflow tract obstruction is imperative and may be lifesaving.

Aorta, Thoracic↗
PubMed1987

A quantitative and qualitative comparison of fibrin glue, albumin, and blood as agents to pretreat porous vascular grafts.

Recent reports suggest that fibrin glue can be used to seal porous vascular grafts prior to insertion, but this ability has not been quantitatively compared to existing methods. We compared blood loss from and handling characteristics of grafts pretreated with either fibrin glue (FG) (Tisseel), albumin autoclaving (AA), or blood preclotting (BP). Five 6-cm segments of 6-mm internal diameter grafts, both knitted and woven double velour Dacron were treated in each group (30 specimens). Human blood was forced through the BP group until clotted; AA segments were soaked in 25% human albumin and autoclaved for 10 min; FG segments were treated with a topical application of Tisseel (0.5 ml/graft) followed by treatment with topical thrombin + CACl (0.5 ml/graft). Graft ends were sealed and attached to a transducer/syringe pump mechanism which pumped heparinized human blood into the graft at 100 mm Hg intraluminal pressure. All blood that leaked through the grafts over 2 min was collected and the amount was averaged for the five grafts in each group. Graft handling was characterized as either pliable or stiff. Blood pretreatment caused 21 +/- 2 and 13 +/- 4 cc/2 min of leak in knitted and woven grafts, respectively. Albumin autoclaving resulted in 9 +/- 2 and 1 +/- 0.5 cc of leak (P less than 0.01 compared to blood), while fibrin glue produced 2 +/- 2 and 0.4 +/- 0.5 cc leaks (P less than 0.01 compared to blood). Both blood and fibrin glue produced soft pliable grafts, while albumin pretreatment resulted in stiff grafts.(ABSTRACT TRUNCATED AT 250 WORDS)

Albumins↗
PubMed1987

Sinus of Valsalva aneurysm complicating bacterial endocarditis in an infant: diagnosis with two-dimensional and Doppler echocardiography.

Sinus of Valsalva aneurysm is a rare complication of bacterial endocarditis in infancy and childhood. This report describes an infant with congenital aortic stenosis who developed bacterial endocarditis after abdominal surgery and placement of indwelling central venous catheters for long-term parenteral nutrition. Bacterial endocarditis in this infant was complicated by the development of an aneurysm of the left sinus of Valsalva. Surgical intervention was necessary because of gradual expansion of the aneurysm with compression of the adjacent right pulmonary artery and descending aorta. Two-dimensional and Doppler echocardiography proved useful for the initial diagnosis and serial follow-up of this unusual disorder and for its successful surgical management.

Aortic Aneurysm↗
PubMed1986

Long-term outcome after repair of coarctation in infancy: subclavian angioplasty does not reduce the need for reoperation.

To assess the influence of surgical technique on the need for reoperation after coarctation repair in infancy, follow-up data were analyzed for 125 consecutive infants (less than 12 months) who underwent repair of coarctation of the aorta by subclavian angioplasty or resection and end to end anastomosis. Sixty-three infants underwent coarctation repair by resection between 1960 and 1980, and 62 underwent subclavian angioplasty between 1977 and 1985. The mean age (+/- SEM) at operation for infants with subclavian flap angioplasty was 1.54 +/- 0.93 months and for infants with resection was 2.70 +/- 0.93 months (p = 0.02). There was no difference between the groups in patient weight at initial repair or the proportion of patients with complex anatomy or aortic arch hypoplasia. Follow-up duration for the subclavian flap group was 2.55 +/- 0.51 years (range 0.3 to 8.2), and for the resection group was 7.97 +/- 3.61 years (range 0.6 to 21). Indication for reoperation was the presence of a coarctation gradient at rest of 40 mm Hg or greater and arm hypertension. Reoperation was required in 5 patients in the subclavian flap group and 12 patients in the resection group. The mean reoperation rate after subclavian flap repair was 0.0356 reoperations per patient-year, and after resection was 0.0342 reoperations per patient-year (p = 0.94). To determine an individual's risk of requiring reoperation from these group measures, a reoperation risk model was developed. The risk of reoperation by the fifth postoperative year was found to be 16.3% after subclavian flap repair and 15.7% after resection.(ABSTRACT TRUNCATED AT 250 WORDS)

Angioplasty, Balloon↗
PubMed1986

Fifty years' experience with esophageal atresia and tracheoesophageal fistula. Beginning with Cameron Haight's first operation in 1935.

Four hundred twenty-six patients with esophageal atresia with or without tracheoesophageal fistula have been primarily cared for at the University of Michigan Medical Center since Cameron Haight's initial experience with this entity. Over the period of observation, the incidence of new cases as well as the number of associated anomalies has remained constant. The long-term survival of these patients has steadily improved over the past half-century from 36% in the pre-1950 era to 84% during the most recent 20 years. Conversely, operative mortality has shown a progressive decline from 56% early in the authors' series to 6.9% more recently, despite a steady increase in the proportion of high-risk neonates seen at the University of Michigan Medical Center during this time span. In the last 9 years, there have been no postoperative deaths in group A or B risk infants (36 patients), while the rate has been 18.2% in group C risk babies (27 patients); almost all of these deaths were due to severe associated anomalies. During the last 10 years, the authors have changed their technique of anastomosis from a two- to a one-layer method while still advocating a primary repair via an extrapleural approach. Although this change has resulted in a modest increase in the rate of anastomotic leak (17% vs. 6.2%, p less than 0.03), the leaks have been small and asymptomatic because of the extrapleural approach and, as a result, have been managed conservatively without any untoward sequelae. Conversely, there has been a significant decrease in the rate of stricture formation with the one-layer anastomosis (4.3% vs. 23.3%, p less than 0.002). While this may in part be explained by the change in anastomotic technique, it is felt that the more aggressive diagnosis and surgical management of gastroesophageal reflux (seen in 37.9% of our recent group) have contributed greatly to this decrease. The steady improvement in survival over this 50-year period, in spite of the increasing number of high-risk infants, is attributable to major improvements in neonatal care before, during, and after operation.

Esophageal Atresia↗
PubMed1986

Prognostic factors in valvotomy for critical aortic stenosis in infancy.

Aortic valvotomy for critical aortic stenosis in infancy has had a high mortality. To determine the factors that influence survival, we reviewed the cases of 24 infants who underwent aortic valvotomy in the first 6 months of life (mean 4 1/2 weeks) for aortic stenosis from 1978 to 1984. Cardiopulmonary bypass was used in all patients. Operative mortality was 21% (5/24), four of the five deaths occurring from low cardiac output. Analysis of preoperative factors affecting survival versus nonsurvival revealed that low ejection fraction (60% +/- 17% in survivors versus 36% +/- 2% in nonsurvivors), high left ventricular end-diastolic pressure (16 +/- 7 mm Hg in survivors versus 30 +/- 14 mm Hg in nonsurvivors), and presence of endocardial fibroelastosis (25% in survivors versus 100% in nonsurvivors) all were predictive of a poor outcome, although the small sample size indicated caution in interpreting results. Factors that did not appear to influence survival included peak systolic gradient (79 +/- 30 mm Hg in survivors versus 60 +/- 15 mm Hg in nonsurvivors) and left ventricular end-diastolic volume (37 +/- 17 cm3/m2 in survivors versus 36 +/- 7 cm3/m2 in nonsurvivors). Four patients with a left ventricular end-diastolic volume below 26 cm3/m2 survived. Postoperative gradients averaged 25 +/- 21 mm Hg at 3.4 +/- 2 years' follow-up in nine recatheterized patients. Ejection fraction of these patients increased from 45% +/- 10% to 70% +/- 11% and left ventricular end-diastolic volume increased from 37 +/- 17 to 58 +/- 5 cm3/m2. Two of 17 patients have required apical-aortic conduits; all other patients are asymptomatic. We conclude that infants with critical aortic stenosis benefit from valvotomy even with impaired left ventricular function and severely reduced left ventricular dimensions and many have nearly normal hemodynamics on late follow-up.

Age Factors↗
PubMed1985

Surgical treatment of cardiac pheochromocytomas.

The development at our institution of the radiopharmaceutical 131-I-metaiodobenzylguanidine has permitted for the first time scintigraphic localization of pheochromocytomas. By the use of this scan in combination with contrast-enhanced computed tomography, intrapericardial pheochromocytomas have been demonstrated in eight patients at our hospital during the past 2 years. Four of these patients have been operated upon by us, and each was found to have a pheochromocytoma arising from the heart (left atrium in three and interventricular groove at the aortic root in one). While in one patient it was possible to "shell" the tumor away from the left atrial wall without cardiopulmonary bypass, in the remaining patients, bypass and cardioplegia were required to resect the pheochromocytomas without inducing life-threatening intraoperative hypertension and cardiac arrhythmias. One patient required coronary artery reconstruction and two, excision of the posterior left atrial wall with pericardial replacement. One of these latter two patients died intraoperatively of uncontrollable hemorrhage. The three remaining patients are well and normotensive after more than 1 year of follow-up. Cardiac pheochromocytomas should not be approached as typical posterior mediastinal tumors, or as they are in the abdomen, with the expectation that they will "shell away" from contiguous structures. Cardiopulmonary bypass should be available, and resection of involved myocardium may be necessary for complete removal.

3-Iodobenzylguanidine↗
PubMed1984

Coronary vasodilator reserve in young dogs with moderate right ventricular hypertrophy.

The effects of experimental right ventricular (RV) pressure overload and RV hypertrophy on coronary vasodilator reserve in young animals is not well established. Therefore, we measured coronary vasodilator reserve in the right ventricle of dogs from 7 to 12 months old with moderate RV hypertrophy due to pulmonary artery banding performed 3 to 7 days after birth. In the 5 dogs with pulmonary artery banding, substantial RV hypertension developed (RV pressure at rest, 73 +/- 11 mm Hg) as did RV hypertrophy (ratio of RV free wall/left ventricular free wall weight, 1.86 +/- 0.41 gm/kg). The reactive hyperemic response following brief coronary occlusions was used as an index of coronary vasodilator reserve. The ratios of peak reactive hyperemic response to resting flow, however, were not significantly different in the 5 banded dogs compared with 7 control animals (3.6 +/- 1.0 versus 2.6 +/- 0.6); this implies that the extent of vasodilator reserve was similar with or without moderate RV hypertrophy. In addition, myocardial blood flow, as determined using radioactive microspheres, was not significantly different at rest: 0.57 +/- 0.09 ml/min per gram in the banded dogs versus 0.48 +/- 0.12 ml/min per gram in the controls. Uniform transmural distribution of blood flow was maintained during infusion of isoproterenol, which was used to increase myocardial oxygen requirements in both groups. Minimum coronary vascular resistance was significantly lower in the banded than the control dogs (1.5 +/- 0.6 versus 6.2 +/- 2.3; p less than 0.01). This difference suggests that the cross-sectional area of the right coronary vascular bed increased with the development of RV hypertrophy.

Animals↗
PubMed1984

Apicoaortic valved conduits for complex left ventricular outflow obstruction: technical considerations and current status.

The surgical considerations, clinical follow-up, and hemodynamic data for 23 patients (age range, 4 months to 80 years) who underwent insertion of a porcinevalved apicoaortic conduit between December, 1976, and June, 1983, are reviewed. All patients had complex forms of left ventricular outflow obstruction. All were symptomatic, and 18 had had 23 prior attempts at surgical relief of the obstruction. There was a total of 6 deaths (26%); 2 were in small children with other complex cardiac malformations, and 2 others in patients who required emergency operation for acute cardiac decompensation. Sixteen patients have had cardiac catheterization 1 to 1.5 years postoperatively, and a reduction in the resting left ventricular-aortic gradient from 91 +/- 30 to 13 +/- 8 mm Hg was demonstrated (p less than 0.001). None of the patients is taking anticoagulants, and no thromboembolic events have occurred. Four of the 17 survivors have undergone a subsequent operation 1.5 to 4.0 years postoperatively with conduit removal, aortoventriculoplasty, and conduit valve replacement in 1, 1, and 2 patients, respectively. These data demonstrate that the apicoaortic conduit is effective in relieving complex left ventricular outflow obstruction and improving left ventricular performance with acceptable long-term results. Increasing the durability of the conduit valve will greatly improve the late results with this technique.

Adolescent↗