Biomedical subjects

Robert E Michler

Publications and source records attributed to Robert E Michler.

9 recordsLinked to original sources

PubMed2003

Off-pump coronary artery bypass grafting does not decrease the incidence of atrial fibrillation.

BACKGROUND: Postoperative atrial fibrillation remains a significant source of morbidity after coronary artery bypass grafting. We reviewed the data on 2,569 patients to determine if the absence of cardiopulmonary bypass resulted in a lower incidence of atrial fibrillation. METHODS: All patients undergoing coronary artery bypass grafting without cardiopulmonary bypass from January 1, 1997 through June 30, 2001 were evaluated for postoperative atrial fibrillation. The data of 252 patients with no cardiopulmonary bypass (group 1) were reviewed and compared with three other patient groups. Group 2 consisted of 1,470 patients using cardiopulmonary bypass during the same study period. Group 3 consisted of 841 patients with a similar number of grafts as the study group but using cardiopulmonary bypass. Group 4 consisted of historical data for 847 patients operated on using cardiopulmonary bypass collected from January 1995 through December 1996. Prophylactic beta-blockade was instituted in January 1997. Groups 1 to 3 received this treatment, but group 4 did not. RESULTS: Group 1 had an incidence of atrial fibrillation of 8.8%. Groups 2, 3, and 4 had incidences of atrial fibrillation of 11.6%, 9.4%, and 28.0%, respectively. When compared with group 1, the incidence of atrial fibrillation in group 4 was statistically different (p <. 0001). CONCLUSIONS: Avoiding cardiopulmonary bypass did not aid the reduction of atrial fibrillation at our institution.

Aged↗

PubMed2002

Overexpression of soluble fas attenuates transplant arteriosclerosis in rat aortic allografts.

BACKGROUND: The killing of vascular cells by activated macrophages is an important step in the process of destabilization of the arterial wall. The death receptor Fas is implicated in vascular cell death. Hence, we extended our studies in a rat aortic allograft model, using adenovirus-mediated overexpression of soluble Fas (sFas) to block Fas binding to Fas ligand (Fas-L). The contribution of Fas to vascular cell injury and consequent transplant arteriosclerosis was investigated. METHODS AND RESULTS: Activated monocytes in the presence of macrophage colony-stimulating factor induce endothelial cell apoptosis in vitro, which was significantly inhibited by adenovirus-mediated sFas overexpression. Next, donor rat abdominal aortas were either untreated or transduced with adenoviruses encoding (1) rat soluble Fas (Ad3rsFas), (2) no insert (Ad3Null), and (3) beta-galactosidase (Ad3nBg). A total of 175 aortic grafts were harvested 2 to 90 days after transplantation. Vascular cell apoptosis and CD45+ cell infiltration were significantly reduced in Ad3rsFas-transduced aortas, as compared with control allografts. Moreover, the control allografts developed marked intimal thickening, whereas Ad3rsFas-transduced allografts had significantly less neointima until the 90-day time point. CONCLUSIONS: sFas overexpression protects the integrity of the vessel wall from immune injury and attenuates transplant arteriosclerosis.

Adenoviridae↗

PubMed2002

Norepinephrine elicits beta2-receptor-mediated dilation of isolated human coronary arterioles.

BACKGROUND: The exact role of adrenoceptors in norepinephrine (NE)-mediated regulation of the human coronary circulation has yet to be elucidated. Thus, the goals of this study were to characterize the adrenoceptors involved in the responses to NE in isolated human coronary arterioles and small arteries. METHODS AND RESULTS: Arterioles (n=39) and small arteries from the left ventricle of explanted human hearts were isolated and cannulated. Vessels from the hearts of 21 patients were studied: 15 males and 6 females, aged 0.5 to 63 years. Nineteen patients were considered to be New York Heart Association class 4. All hearts exhibited hypertrophy (190+/-20%). The passive diameter of arterioles was 167+/-8 microm (range 97 to 323 microm). NE (10(-7) to 3x10(- 7) mol/L) elicited concentration-dependent dilations (47+/-4 microm) that were unaffected by endothelium removal, N(omega)-nitro-L-arginine (10(- 4) mol/L, an NO synthase inhibitor), or practolol (10(-6) mol/L, a beta1-receptor blocker). However, administration of propranolol (10(-5) mol/L, a combined beta1- and beta2-blocker) or butoxamine (10(-6) mol/L, a beta2-receptor blocker) completely eliminated the NE-induced dilation. Constrictions to NE (2 of 39 vessels) were inhibited by prazosin (10(-6) mol/L, an alpha1-receptor blocker). Methoxamine (10(-9) to 10(-5) mol/L, an alpha1-agonist) had no effect, whereas U44619, a thromboxane mimetic, elicited dose-dependent constriction of vessels. CONCLUSIONS: Our data indicate that isolated human coronary arterioles and small arteries dilate to NE via beta2-receptors on smooth muscle. These findings are important to our understanding of the mechanisms action of NE in the human coronary circulation.

Adolescent↗

PubMed2002

Ex-vivo mitral valve repair prior to orthotopic cardiac transplantation.

Mitral valve annuloplasty was performed prior to orthotopic cardiac transplantation in two donor hearts which were diagnosed with moderate to severe mitral regurgitation. The technical aspects are reviewed of ex-vivo mitral valve repair with concomitant heart transplantation. The recipients were classified as United Network for Organ Sharing (UNOS) I and both patients have had an excellent postoperative recovery. Over 2-year follow-up demonstrates normal mitral valve function without regurgitation.

Heart Failure↗

PubMed2002

An alternative surgical approach to facilitate minimally invasive mitral valve surgery.

An alternative approach to minimally invasive mitral valve surgery is described that permits direct great vessel cannulation and direct aortic clamp occlusion through a 6- to 8-cm incision. This approach reduces the complexity of the procedure, and hopefully, will contribute to more widespread adoption of less invasive techniques in mitral valve surgery.

Cardiopulmonary Bypass↗

PubMed2002

Short- and long-term results of open heart surgery in patients with abdominal solid organ transplant.

OBJECTIVES: Cardiac disease is a common cause of mortality and morbidity in patients with abdominal solid organ transplant. Improvement of the results of abdominal organ transplantation has contributed to an increasing pool of patients who require open heart surgery. We investigated short- and long-term results of open heart surgery in patients with functioning abdominal solid organ transplants. METHODS: We retrospectively examined 60 patients (52.5 years in average) undergoing coronary artery bypass grafting and/or valve surgery since July 1988 after abdominal organ transplantation. There were 22 females (37%). They consisted of 46 kidney, nine kidney-pancreas and five liver recipients. Cardiac surgery was performed 68.9 months after transplantation. Preoperative serum creatinine level was 2.1 mg/dl, and 11 patients (18%) had creatinine level more than 3.0 mg/dl. Eleven patients (18%) were operated upon on non-elective basis. Twelve patients (20%) were not given stress-dose steroids postoperatively. RESULTS: Three patients died early after surgery (5.0%). Twenty-six major complications were seen in 17 patients (28%), including deterioration of renal function in seven (three patients required temporary hemodialysis), three major infections, two bleeding complications, and two strokes. No graft loss was encountered. No differences were seen in mortality and morbidity between patients with or without stress-dose steroids. Multivariate analysis identified cardiopulmonary bypass time (P<0.05) as a risk factor for operative death, preoperative creatinine level (P<0.05), cardiopulmonary bypass time (P<0.05) and the amount of fresh frozen plasma used (P<0.05) for major complication, non-elective surgery (P<0.01) for deterioration of renal function. Thirteen patients died and five kidney allografts failed late after surgery. Three- and 5-year patient and graft survivals were 70.8 and 66.8, 84.5 and 84.5%, respectively. Multivariate regression analysis identified female gender (P<0.05), body mass index (P<0.001) and non-elective surgery (P<0.001) as risk factors for late death, and preoperative creatinine level (P<0.05) for late graft loss. CONCLUSIONS: Open heart surgery can be performed with acceptable short- and long-term results in patients with functioning abdominal transplants. Stress-dose steroid may be unnecessary in selected patients. Aggressive use of open heart surgery in this patient population to avoid non-elective surgery may further improve early and late surgical outcomes.

Adult↗

PubMed2002

Minimally invasive mitral valve replacement and multivessel coronary artery bypass through a limited right lateral thoracotomy using a balloon aortic cannula.

Mitral valve replacement and coronary artery bypass grafting were performed in an 80-year-old woman through an 8 cm lateral thoracotomy using central cannulation with a balloon aortic cannula. Visualization permitted the delivery of both retrograde and antegrade cardioplegia. This technique provides excellent exposure of the mitral valve and all coronary vessels and decreases the operative risks associated with a sternotomy.

Aged↗

PubMedDate not supplied

Saphenous vein graft aneurysm: potential for mistaken identity.

We report the unusual presentation of a saphenous vein graft aneurysm in a 72-year-old man who had undergone coronary artery bypass surgery 15 years prior to admission. The patient presented with a large mass on the anterior wall of the right ventricle and chest discomfort; initially believed to be a cardiac tumor. The patient underwent reoperative coronary surgery with excision of the saphenous vein graft aneurysm, followed by an uneventful postoperative course. Aortocoronary saphenous vein graft aneurysms are rare and their presentation may be mistaken for pulmonary or chest wall lesions. Complications include rupture, and therefore require attentive diagnosis and surgical therapy.

Aged↗

PubMedDate not supplied

Dextrocardia: technical aspects of reoperative aortic and tricuspid valve replacement.

Tricuspid and aortic valve replacement was performed on a 50-year old man with dextrocardia, situs solitus, D-ventricular looping, and normally related great arteries. Twenty-two years earlier the patient had undergone repair of an incomplete atrioventricu lar canal and mitral valve replacement. The anatomic issues and operative considerations are discussed for aortic and tricuspid valve replacement in this anatomic situation with special emphasis on tricuspid valve replacement through a right ventriculotomy. Six months after surgery, New York Heart Association functional class improved from class III preoperatively, to class II.

Aortic Valve Insufficiency↗