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Michael A Borger

Publications and source records attributed to Michael A Borger.

17 recordsLinked to original sources
PubMed2004

Aortovenous bypass graft to the posterior left ventricle in absence of an identifiable coronary artery.

We report the case of a 70-year-old woman with significant intermediate coronary artery stenosis who underwent a series of stent procedures, ultimately leading to compromise of the origin of the circumflex artery. Intraoperatively, identification of an obtuse marginal coronary artery was impossible due to a thick layer of epicardial fat, calcification of the posterior atrioventricular groove, and an adherent, thickened pericardium. Therefore, a saphenous vein graft to the posterior vein of the left ventricle was constructed with ligation of the vein cephalad. This uncommon approach to surgical revascularization effectively relieved the patient's angina and may be of use in other difficult cases.

Aged↗
PubMed2004

Predictors of delirium after cardiac surgery delirium: effect of beating-heart (off-pump) surgery.

BACKGROUND: Despite improved outcomes after cardiac operations, postoperative delirium remains a common complication that is associated with increased morbidity and prolonged hospital stay. METHODS: Univariate and multivariate predictors of postoperative delirium were determined from prospectively gathered data on 16,184 patients undergoing cardiac operations with cardiopulmonary bypass (conventional, n = 14,342) and without cardiopulmonary bypass (beating-heart surgery, n = 1847) between April 1996 and August 2001. Delirium was defined as a transient mental syndrome of acute onset characterized by global impairment of cognitive functions, a reduced level of consciousness, attentional abnormalities, increased or decreased psychomotor activity, and a disordered sleep-wake cycle. RESULTS: The overall prevalence of postoperative delirium was 8.4%. Of 49 selected patient-related risk factors and treatment variables, 35 were highly associated with postoperative delirium by univariate analysis. Stepwise logistic regression revealed the following variables as independent predictors of delirium: history of cerebrovascular disease, peripheral vascular disease, atrial fibrillation, diabetes mellitus, left ventricular ejection fraction of 30% or less, preoperative cardiogenic shock, urgent operation, intraoperative hemofiltration, operation time of 3 hours or more, and a high perioperative transfusion requirement. Two variables were identified as having a significant protective effect against postoperative delirium: beating-heart surgery and younger patient age. CONCLUSIONS: Postoperative delirium is a common complication in cardiac operations. The increased use of beating-heart surgery without cardiopulmonary bypass may lead to a lower prevalence of this complication and thus improve patient outcomes.

Age Distribution↗
PubMed2004

Prevention and management of deep sternal wound infection.

Deep sternal wound infection (DSWI) is an uncommon but serious complication of median sternotomy in cardiac surgery, associated with significant mortality and morbidity. We performed a retrospective review of 30,102 consecutive cardiac surgical patients operated on at our institution from 1990 to 2003 and found an incidence of DSWI of 0.77%. The in-hospital mortality rate was 6.9% for DSWI patients versus 2.8% for patients without DSWI (P = 0.0002). Multivariable predictors for development of DSWI were old age, diabetes, previous stroke or TIA, and congestive heart failure. The use of bilateral internal thoracic artery (BITA) grafts increased the risk of DSWI in patients undergoing coronary artery bypass surgery, particularly in those with congestive heart failure alone or with diabetes. Skeletonization of BITA grafts resulted in a lower risk of DSWI, comparable to nondiabetic patients (1.3% versus 1.6%, P = 0.8). Patients with DSWI were treated with either sternal debridement and primary closure or sternectomy with myocutaneous flap reconstruction, resulting in a 6-month freedom from adverse event rate of 76% in both groups.

Cardiac Surgical Procedures↗
PubMed2003

Stroke after cardiac surgery: a risk factor analysis of 16,184 consecutive adult patients.

BACKGROUND: Stroke remains a devastating complication after cardiac surgical procedures despite advances in perioperative monitoring and management. The purpose of this study was to determine the predictors of stroke in a large, contemporary cardiac surgery population. METHODS: Prospective data on 16,184 consecutive patients undergoing cardiac surgery (coronary artery bypass grafting [CABG], n = 8,917; beating heart CABG, n = 1,842; aortic valve surgery, n = 1,830; mitral valve surgery, n = 708; double or triple valve surgery, n = 381; CABG and valve surgery, n = 2,506) between April 1996 and August 2001 were subjected to univariate and multivariate analysis. Stroke was defined as any new permanent (manifest stroke) or temporary neurologic deficit or deterioration (transient ischemic attack or prolonged reversible ischemic neurologic deficit) and was confirmed by computed tomography or magnetic resonance imaging whenever possible. RESULTS: Overall incidence of stroke was 4.6% and varied between surgical procedures (CABG 3.8%; beating-heart CABG 1.9%; aortic valve surgery 4.8%; mitral valve surgery 8.8%; double or triple valve surgery 9.7%; CABG and valve surgery 7.4%). Of 63 patient-specific and treatment variables, 54 were found to have a significant univariate association with postoperative stroke. Multivariable analysis revealed 10 variables that were independent predictors of stroke: history of cerebrovascular disease, peripheral vascular disease, diabetes, hypertension, previous cardiac surgery, preoperative infection, urgent operation, CPB time more than 2 hours, need for intraoperative hemofiltration, and high transfusion requirement. Beating heart CABG was associated with a lower incidence of stroke in this multivariable analysis. CONCLUSIONS: Identification of predictors for stroke is important for understanding the pathogenesis of this devastating complication as well as for developing preventative strategies. Although retrospective analyses can be subject to selection bias we believe beating heart CABG is associated with a lower incidence of stroke and may therefore improve patient outcomes.

Adult↗
PubMed2003

Extending the in situ right internal mammary artery graft with retrocaval positioning.

Bilateral internal mammary artery grafting is associated with improved long-term patient outcomes. In situ right internal mammary artery grafting of the obtuse marginal artery, through the transverse sinus, is often limited by conduit length. We describe the technique of retrocaval positioning of the right internal mammary artery graft to extend its functional length for grafting of the circumflex territory. With careful surgical technique, this procedure can be performed safely during routine coronary bypass operations.

Coronary Artery Bypass↗
PubMed2003

Secundum ASD closure using a right lateral minithoracotomy: five-year experience in 122 patients.

BACKGROUND: Surgical closure of secundum atrial septal defect (ASD) is a standard procedure associated with very low mortality and morbidity. We evaluated outcomes in the era of catheter-based interventional closure and minimally invasive techniques. METHODS: From May 1996, February 2002, 177 patients with a body weight of more than 30 kg underwent surgical ASD closure. A right lateral minithoracotomy (LMT) was used in 122 patients and a conventional approach, in 55. Diagnoses included secundum ASD in 106 patients in the LMT group and 40 in the conventional group, sinus venosus ASD in 13 patients in each group, and status post interventional closure in 3 and 2 patients, respectively. Mean age was 37 +/- 17 years in the LMT group and 43 +/- 20 years, in the conventional group and mean body weight was 66 +/- 17 kg and 70 +/- 16 kg, respectively. In the LMT group, femoral cannulation was performed for cardiopulmonary bypass. RESULTS: Direct ASD closure was carried out in 67.2% of patients in the LMT group and 58.2% of those in the conventional group. The remaining patients had pericardial patch closure. There was one death: A patient in the conventional group who required explantation of an Amplatzer device because of infection died postoperatively. Average stay in the intensive care unit was 1.2 +/- 0.5 days. Two patients required reoperation for residual ASD after direct closure; 1 sustained a temporary neurological deficit that resolved completely. On postoperative echocardiography, a minimal residual shunt was seen in only 3 patients. All patients were in good clinical condition with improved functional status at discharge from the hospital. CONCLUSIONS: Secundum ASD closure by LMT has become as standard and safe an operation as the conventional technique and achieves good perioperative results and satisfactory long-term outcomes. Thus LMT is an attractive option for patients who are not suitable for closure using catheter-based devices.

Adolescent↗
PubMed2003

Skeletonization of bilateral internal thoracic artery grafts lowers the risk of sternal infection in patients with diabetes.

OBJECTIVE: Deep sternal wound infection is a dreaded complication of coronary artery bypass surgery, particularly in patients with diabetes. This study determines whether skeletonization of internal thoracic artery conduits compared with pedicled harvesting reduces the risk of deep sternal wound infection in patients with diabetes undergoing bilateral internal thoracic artery grafting. METHODS: We reviewed prospectively gathered data on all patients who have undergone coronary artery bypass grafting and received bilateral internal thoracic artery grafts at our institution since 1990. We compared patients with diabetes who received skeletonized (n = 79) versus conventional pedicled (n = 36) internal thoracic artery conduits. RESULTS: The proportion of patients taking insulin (19.0% vs 14.0% for skeletonized vs conventional grafts, respectively, P =.6) or oral hypoglycemic agents (68.4% vs 69.4%, P =.9), as well as the prevalence of type I diabetes (2.5% vs 8.3%, P =.18), were similar in both groups. Patients who received skeletonized grafts were more likely to receive a free rather than an in situ right internal thoracic artery graft (93.7% vs 30.6%, P <.001). The prevalence of deep sternal wound infection was significantly lower in patients who received skeletonized grafts compared with patients who received conventional grafts (1.3% vs 11.1%, P =.03). Patients in the skeletonized group were also less likely to develop any (superficial or deep) sternal wound infection postoperatively (5.1% vs 22.2%, P =.03). There was no significant difference in the prevalence of deep sternal wound infection between patients with diabetes who received skeletonized internal thoracic arteries and patients without diabetes who underwent conventional internal thoracic artery grafting (n = 578) (1.2% vs 1.6%, respectively, P =.8). CONCLUSIONS: Skeletonization of internal thoracic artery conduits lowers the risk of deep sternal wound infection in patients with diabetes undergoing bilateral internal thoracic artery grafting. We no longer consider diabetes a contraindication to bilateral internal thoracic artery grafting, provided the internal thoracic arteries are skeletonized.

Adult↗
PubMed2003

Esophageal perforation during left atrial radiofrequency ablation: Is the risk too high?

OBJECTIVE: Intraoperative radiofrequency ablation of atrial fibrillation (IRAAF) is a recently developed procedure being performed in an increasing number of patients. We have performed left atrial IRAAF in 387 patients since August 1998. The purpose of this article is to describe a serious complication of this procedure, namely IRAAF-induced esophageal perforation, in detail to identify possible risk factors. METHODS: Left atrial IRAAF was performed with a commercially available unipolar probe as an isolated procedure (n = 129) or in combination with mitral valve surgery (n = 163) or other surgical procedures (n = 95). Operations were performed either through a conventional sternotomy or right minithoracotomy. RESULTS: Four (1%) patients had esophageal perforation after radiofrequency ablation. All 4 patients presented after an initially unremarkable postoperative course, with sudden neurologic symptoms from esophagoatrial air embolization occurring in 3 of the patients. Three patients were successfully treated with extensive esophageal resection, and one died from massive air embolism. All perforations occurred in patients undergoing minimally invasive IRAAF. Comparison with other patients undergoing isolated minimally invasive IRAAF (n = 129) failed to reveal any reliable predictors of esophageal injury, including patient body size, operating times, or radiofrequency biophysical parameters. CONCLUSIONS: Left atrial IRAAF is associated with a small but definite risk of esophageal perforation. Unfortunately, we were unable to identify any risk factors for this life-threatening complication. A high degree of vigilance must be maintained for esophageal injury after IRAAF, particularly in patients with new neurologic deficits. Until safer methods of ablation are developed, we currently recommend against the use of IRAAF in patients undergoing cardiac surgery.

Adult↗
PubMed2002

Extending the usable size range of homografts in the pulmonary circulation: outcome of bicuspid homografts.

BACKGROUND: Small-sized homografts are often not available, making the use of surgically reduced cryopreserved homograft conduits appealing. METHODS: From January 1993 to January 2000, 21 large homografts were size-reduced by excising one leaflet and were implanted in the pulmonary circulation. Valve function was compared with 21 children-matched for weight, homograft size, and year of operation-who received a standard homograft. RESULTS: Implanted homograft size and patient weight were equivalent in both the bicuspid and standard groups. Median (range) in-hospital peak instantaneous echocardiographic gradient across the valve was 0 mm Hg (0 to 19) in the bicuspid group versus 0 mm Hg (0 to 17) in the standard group (p = 0.65). Median (range) in-hospital pulmonary insufficiency (scale of 0 to 4) was 2 (0 to 3) in the bicuspid group versus 1.5 (0 to 3) in the standard group (n = 10, p = 0.34). At a follow-up of 54+/-29 months there was no significant difference in conduit reinterventions between the groups. CONCLUSIONS: Surgical creation of a bicuspid valve in the pulmonary circulation results in a functionally equivalent conduit compared with standard homograft as measured by early and midterm valve function.

Cardiac Surgical Procedures↗
PubMed2002

Minimal access aortic valve replacement: effects on morbidity and resource utilization.

BACKGROUND: The aim of this study was to compare outcomes in patients undergoing minimal access versus conventional aortic valve replacement (AVR). METHODS: We reviewed prospectively gathered data on all patients who were undergoing first-time AVR, with or without replacement of the ascending aorta, over a 1-year period at our institution. RESULTS: A total of 176 patients underwent minimal access and 258 underwent conventional AVR. The conventional group was older, had more incidence of diabetes, and more aortic stenosis (all p < 0.05). Eight minimal access AVR patients (2%) required conversion to a complete sternotomy. Minimal access AVR patients had longer aortic crossclamp times than conventional AVR patients (60 +/- 22 vs 55 +/- 23 minutes, p = 0.03) but similar CPB times (93 +/- 38 vs 88 +/- 42 minutes, p = 0.20). Postoperative creatine kinase-MB levels were similar for the two groups. Total postoperative blood loss was significantly lower in the minimal access group, and these patients received less red blood cell and fresh frozen plasma transfusions. Minimal access AVR patients were less likely to have postoperative respiratory failure (3% vs 10%); they had shorter intensive care unit stays (3.7 +/- 5.4 vs 4.5 +/- 5.6 days) and shorter hospital stays (10 +/- 6 vs 12 +/- 7 days, all p < 0.05). Mortality was lower in patients undergoing minimal access surgery (3% vs 9%, p = 0.008) by univariate analysis. Multivariate predictors of mortality were age, hypertension, and CPB time. CONCLUSIONS: Although patient selection may have influenced some of the observed differences between our patient groups, minimal access surgery appears to be associated with decreased morbidity and resource use when compared to conventional AVR.

Aortic Valve↗
PubMed2002

Reoperative mitral valve replacement: importance of preservation of the subvalvular apparatus.

BACKGROUND: Preservation of the subvalvular apparatus has been demonstrated to be beneficial during first-time mitral valve replacement (MVR), but has not been fully examined in reoperative (redo) MVR. The purpose of this study was to analyze outcomes in a large cohort of redo MVR patients, focusing on the effect of subvalvular preservation on mortality. METHODS: We undertook a review of prospectively gathered data on patients undergoing MVR, with or without concomitant cardiac procedures, at our institution from 1990 to 1999. Predictors of mortality were determined by stepwise logistic regression. RESULTS: A total of 1,521 consecutive MVR patients were analyzed, of which, 513 (34%) had undergone one or more previous MV procedures. In-hospital mortality occurred in 6.9% of first-time MVR patients versus 9.0% in redo patients (p = 0.13). The number of prior MV operations ranged from one to five in redo MVR patients, with 115 patients (22% of redos) having two or more. In redo MVR patients, preservation of the native posterior subvalvular apparatus was performed in 103 patients (21%), whereas native anterior and posterior preservation was performed in 31 patients (6%). Gore-Tex neochordal construction was performed in 135 redo MVR patients (26%). Perioperative mortality occurred in 3.6% of redo MVR patients with a preserved subvalvular apparatus (native tissue and/or Gore-Tex reconstruction) versus 13.3% of redo patients without preservation (p < 0.001). Independent predictors of mortality in redo MVR patients were (in decreasing order of magnitude) failure to preserve the subvalvular apparatus, preoperative renal failure, previous stroke/transient ischemic attack, left ventricular dysfunction (left ventricular ejection fraction <40%), and urgent timing. CONCLUSIONS: Redo MVR can be performed with an acceptable risk of mortality. Although preservation of the subvalvular apparatus may increase operative complexity, we recommend subvalvular preservation in order to decrease the risk of early mortality.

Adult↗
PubMed2002

Regional overexpression of insulin-like growth factor-I and transforming growth factor-beta1 in the myocardium of patients with hypertrophic obstructive cardiomyopathy.

OBJECTIVE: Hypertrophic obstructive cardiomyopathy has been proposed to be the result of gene mutations of contractile proteins. However, we have previously shown significant elevation of insulin-like growth factor-I (IGF-I) and transforming growth factor-beta1 (TGF-beta1) at the messenger RNA, protein, and receptor levels in patients with hypertrophic obstructive cardiomyopathy when compared with myocardium from patients without this disorder. We hypothesized that this growth factor overexpression is a regional phenomenon. To test this hypothesis, we compared levels of IGF-I and TGF-beta1 in hypertrophic and nonhypertrophic myocardium within the same group of patients with hypertrophic obstructive cardiomyopathy. METHODS: Two biopsy specimens were obtained from each patient undergoing septal myectomy for severely symptomatic hypertrophic obstructive cardiomyopathy, from hypertrophied septum and from nonhypertrophied myocardium (8 patients in total). Clinical data were prospectively recorded. Messenger RNA levels for growth factor were quantified by means of multiplex reverse transcriptase-polymerase chain reaction, expressed as a densitometric ratio of growth factor/glyceraldehyde-3-phosphate dehydrogenase. Protein levels were quantified by means of chemiluminescent slot blot analysis. Growth factor proteins were used to generate a standard curve. RESULTS: IGF-I messenger RNA and protein levels in hypertrophic myocardium were 2.6 and 2.9 times greater, respectively, than in nonhypertrophic myocardium of the same patients (both P <.01). TGF-beta 1 messenger RNA and protein levels in the hypertrophic myocardium were 2.5 and 2.8 times greater, respectively, than the levels in the nonhypertrophied myocardium (both P <.01). There was a significant correlation between the IGF-I protein ratio (hypertrophic/nonhypertrophic myocardium) and the inducible left ventricular outflow tract gradients measured at cardiac catheterization (r = 0.77, P =.025). CONCLUSIONS: Myocardial overexpression of IGF-I and TGF-beta1 is a regional phenomenon in patients with hypertrophic obstructive cardiomyopathy and is likely involved in the pathogenesis of the disorder.

Cardiomyopathy, Hypertrophic↗
PubMed2002

The insulin cardioplegia trial: myocardial protection for urgent coronary artery bypass grafting.

BACKGROUND: Small, nonrandomized clinical trials have demonstrated a beneficial effect of solutions containing insulin and glucose on the recovery of myocardial metabolism and ventricular function after cardioplegic arrest and reperfusion. However, no large, blinded, randomized study has yet determined the effects of insulin-enhanced cardioplegia on clinical outcomes after coronary artery bypass grafting. METHODS: The Insulin Cardioplegia Trial was designed to evaluate the clinical impact of insulin-enhanced cardioplegia on patients at high risk undergoing isolated coronary artery bypass grafting for unstable angina. A total of 1127 patients were randomly assigned at operation to receive cardioplegic solution supplemented with 10 IU/L insulin (n = 557) or placebo (n = 570). All personnel with direct patient contact were blinded to randomization group. RESULTS: Overall operative mortality was 2.2%, with no significant differences between groups. The prevalences of postoperative low output syndrome (insulin 10.4%, placebo 9.7%, P =.7) and enzymatic myocardial infarction (insulin 21.0%, placebo 18.8%, P =.3) were not different between groups. The primary composite outcome of low output syndrome and/or enzymatic myocardial infarction revealed no difference between groups (insulin 30.0%, placebo 26.3%, P =.2). CONCLUSIONS: Despite encouraging results from smaller, nonrandomized studies, the Insulin Cardioplegia Trial failed to demonstrate a clinical benefit of insulin-enhanced cardioplegic solution for patients undergoing high-risk isolated coronary artery bypass grafting.

Adult↗
PubMed2002

Cerebral emboli during cardiopulmonary bypass: effect of perfusionist interventions and aortic cannulas.

Neuropsychological impairment is a very common complication of cardiopulmonary bypass (CPB). The principal cause of postoperative cognitive impairment is thought to be cerebral microemboli during CPB. We recently investigated the effects of perfusionist interventions and aortic cannulation techniques on cerebral emboli production during coronary bypass (CABG) surgery. Patients undergoing isolated CABG were monitored with continuous transcranial Doppler ultrasonography of the middle cerebral artery. Perfusionist interventions were defined as injections of drugs into the CPB circuit or acquisition of blood samples from the CPB circuit. Patients were randomized to receive either standard cannulation of the ascending aorta or cannulation of the distal aortic arch. Cerebral emboli were detected in all patients. The number of emboli per minute was markedly higher during perfusionist interventions than during other time periods. Patients with increased perfusionist interventions had worse neuropsychological outcomes. Cannulation of the distal aortic arch, with placement of the cannula tip beyond the cerebral vessels, resulted in significantly less cerebral emboli than cannulation of the ascending aorta. Perfusionist interventions are a common source of cerebral microemboli during CPB, and may contribute to postoperative neuropsychological impairment. Care should be taken to minimize the introduction of air into the bypass circuit during CPB. Provided it is performed safely, distal aortic arch cannulation is a useful technique for reducing cerebral emboli during cardiac surgery.

Aorta↗
PubMedDate not supplied

Temporary extracorporeal membrane oxygenation in patients with refractory postoperative cardiogenic shock--a single center experience.

BACKGROUND: Approximately 1% of patients require temporary circulatory support due to refractory cardiogenic shock following cardiac surgery. Such patients are at very high risk for subsequent morbidity and mortality. We evaluated the results of temporary extracorporeal membrane oxygenation (ECMO) support in patients with postcardiotomy cardiogenic shock. METHODS: From November 1997 to February 2000, 7900 patients underwent cardiac surgery in our institution. Ninety-five patients (1.2%) (CABG, n = 63; AVR, n = 16; CABG and AVR, n = 8; other procedures, n = 8) required temporary postoperative ECMO support. ECMO implantation was performed via the femoral vessels or via the right atrium and ascending aorta. Intraaortic balloon counterpulsation was employed in all patients. RESULTS: Mean duration of ECMO support was 2.8 +/- 2.1 days. Forty-five patients (47%) were successfully weaned from ECMO. Of these, 28 patients were discharged from hospital 35.8 +/- 20.8 days post-ECMO support. Overall hospital mortality for all ECMO patients was considerable at 71%. Mortality rate in the combined CABG and AVR group was 100% (P < 0.05 versus the other surgical groups). ECMO support was complicated by renal failure in 64% of patients, bleeding requiring mediastinal reexploration in 62%, ischemia of the lower limbs in 16%, cerebral edema in 6%, and cerebral hemorrhage in 3%. CONCLUSIONS: ECMO is a suitable technique for short-term treatment of refractory postoperative low cardiac output. Mortality rates are comparable to other cardiac assist devices, with approximately 30% of patients able to be discharged from hospital.

Aged↗
PubMedDate not supplied

Myocardial protection in reoperative coronary artery bypass grafting:.

Redo coronary artery bypass grafting (CABG) is associated with higher morbidity and mortality when compared to first-time CABG. Myocardial infarction and dysfunction contribute significantly to the increased risk of redo CABG. Results of reoperative coronary surgery have gradually improved, largely because of improvements in myocardial protection techniques. In the present review we will highlight the principles of myocardial protection in redo CABG patients with an emphasis on retrograde cardioplegia.

Coronary Artery Bypass↗