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Biomedical subjects

W R Mayfield

Publications and source records attributed to W R Mayfield.

9 recordsLinked to original sources
PubMed1998

Thoracoscopic harvest of the internal thoracic artery: a multicenter experience in 218 cases.

BACKGROUND: Off-pump bypass grafting most commonly involves harvest of the left internal thoracic artery (ITA) through a minithoracotomy under direct vision. Disadvantages to this approach, however, include poor exposure, incomplete dissection resulting in inadequate ITA length, and significant postoperative pain because of rigorous chest retraction. This study determined the safety and efficacy of an alternative to direct ITA harvest using a thoracoscopic approach. METHODS: Two hundred eighteen patients at three institutions underwent thoracoscopic ITA harvest; 118 (54%) for off-pump coronary bypass grafting. RESULTS: The left ITA was harvested in 211 patients (96%); the mean harvest time ranged from 42 to 55 minutes. The ITA was injured in 4 patients (1.8%), and conversion to open ITA harvest occurred in 18 (8%). Complications included intercostal neuropathy (4), reoperation for ITA bleeding (2), phrenic nerve injury (1), and wound infection (1). CONCLUSIONS: This large, multicenter experience demonstrates that thoracoscopic harvest of the ITA can be accomplished safely and within a reasonable time frame in most patients undergoing coronary bypass grafting.

Aged↗
PubMed1998

Endoscopic repeat sternotomy.

BACKGROUND: Repeat cardiac surgery represents eight to twenty five percent of cardiac surgical procedures. Catastrophic hemorrhage is a known complication of repeat sternotomy. A number of techniques have been described to reduce the incidence of injury to the heart and mediastinal structures during reoperation. This paper reports a new endoscopic technique to visualize and lyse the adhesions between the sternum and heart prior to repeat median sternotomy. METHODS: A unique substernal retractor and endoscopic visualization system was developed specifically to facilitate safe and rapid sternotomy in reoperative cardiac cases. Twenty-four patients underwent elective reoperation using the Endoscopic Redo Sternotomy Retractor and instrumentation. There were 5 patients with prior valve surgery and 19 patients with coronary bypass grafts in place. Retrosternal adhesions were divided with special endoscopic cautery or scissors after which a standard reciprocating saw was used to open the sternum without damage to underlying structures. RESULTS: The time required for endoscopic dissection of retrosternal adhesions ranged from 6 to 22 minutes. No injury to any cardiac structure or conduit occurred. CONCLUSIONS: The Endoscopic Redo Sternotomy Retractor provides excellent visualization of all retrosternal structures and adhesions allowing safe and meticulous dissection prior to sternal opening.

Equipment Design↗
PubMed1995

Intrauterine pregnancy and aortic valve replacement.

Cardiopulmonary bypass (CPB) does not appear to cause excessive maternal risk, but the potential for fetal complications is of great concern. In general, operative intervention should be delayed until at least the second trimester. When this is not possible, ethical issues arise and a clash of maternal autonomy versus "fetal rights" ensues. This conflict is further complicated by maternal status changes that may accompany valvular disease or develop after CPB. The case described herein summarizes and discusses these conflicts.

Abortion, Induced↗
PubMed1991

Radiation-associated valvular disease.

The prevalence of radiation-associated cardiac disease is increasing due to prolonged survival following mediastinal irradiation. Side effects of radiation include pericarditis, accelerated coronary artery disease, myocardial fibrosis and valvular injury. We evaluated the cases of three young patients with evidence of significant valvular disease following mediastinal irradiation. One patient underwent the first reported successful aortic and mitral valve replacement for radiation-associated valvular disease (RAVD) as well as concurrent coronary artery revascularization. A review of the literature revealed 35 reported cases of RAVD, with only one successful case of valve replacement that was limited to the aortic valve. Asymptomatic RAVD is diagnosed 11.5 years after mediastinal irradiation compared with 16.5 years for symptomatic patients, emphasizing that long-term follow-up is important for patients receiving mediastinal irradiation. This study defines a continuum of valvular disease following radiation that begins with mild asymptomatic valvular thickening and progresses to severe valvular fibrosis with hemodynamic compromise requiring surgical intervention.

Adolescent↗
PubMed1991

Perivalvular pseudoaneurysm complicating bacterial endocarditis: MR detection in five cases.

Bacterial endocarditis usually affects the valve leaflets, but erosion into the valve anulus and adjacent myocardium may form a myocardial abscess. Perivalvular abscesses can drain into the ventricles or aorta, forming a life-threatening pseudoaneurysm. We reviewed our experience with cardiac MR imaging of this disorder. Fourteen patients with complicated bacterial endocarditis underwent ECG-gated spin-echo cardiac MR imaging in addition to conventional duplex two-dimensional echocardiography (2-D echo). Angiography was performed in seven patients, six of whom underwent surgery for valve replacement. MR imaging detected the pseudoaneurysms in all five of the surgically proved cases, while 2-D echo detected only three. Clinical follow-up suggested there were no false-negative examinations, but no autopsy data were available for confirmation. Postoperative MR imaging studies were conducted in three patients, revealing two recurrent pseudoaneurysms and one thrombosed aneurysm. Cardiac MR imaging provides useful pre- and postoperative information in patients with perivalvular pseudoaneurysms due to endocarditis.

Aneurysm, Infected↗
PubMed1990

Continuous postoperative epidural analgesia for gynecologic oncology patients.

The efficacy of continuous postoperative epidural analgesia (CPEA) was assessed in 193 patients who collectively underwent 254 gynecologic oncology procedures. Seventy-five patients elected to receive CPEA; 118 did not. The CPEA patients received an epidural catheter the morning of surgery. Postoperatively, a bolus of meperidine was placed in each catheter. An IVAC pump continued to deliver meperidine at the rate of 14 to 20 mg per hour. The 193 patients also received a total of 655 postoperative intramuscular narcotic injections. CPEA patients were three times less likely to request injections, and those who did required an average of 6.58 compared with 12.42 for non-CPEA patients. The presence or absence of CPEA was the only significant variable. The use of CPEA led to no secondary complications, and it greatly enhanced mood and ability to participate in postoperative care. We conclude that CPEA provides excellent postoperative analgesia for such high-risk patients.

Adult↗
PubMed1989

Unstable angina pectoris: pathogenesis and management.

Unstable angina is a simple term used to describe a complex group of conditions with a heterogeneous pathogenesis and prognosis. In patients with cardiac disease, understanding pathogenetic mechanisms often influences decisions regarding prognosis and treatment. Potential causes for the development of acute myocardial ischemia include: 1. Extracardiac factors in the patient with severe coronary atherosclerosis. 2. Plaque disruption resulting in: a. Transient platelet aggregation in diseased vessels. b. Dynamic or intermittent coronary artery thrombosis. c. Hemorrhagic dissection into an atheromatous plaque. d. Abnormal constriction of a coronary artery. 3. Progression of atherosclerosis as a result of plaque "healing." It may not be possible to identify the appropriate mechanism responsible for unstable angina in every case but the clinician must attempt to do so since the selection of appropriate therapy for the individual patient depends on the mechanisms responsible for the symptoms.

Angina Pectoris↗
PubMedDate not supplied

Acute vascular rejection of the coronary arteries in human heart transplantation: pathology and correlations with immunosuppression and cytomegalovirus infection.

Prior studies of vascular rejection in transplanted human hearts have stressed the importance of accelerated coronary arteriosclerosis (chronic vascular rejection). We, however, have had four patients with sudden onset of acute heart failure within 90 days of transplantation who have died without significant myocardial interstitial rejection or the concentric intimal thickening with dense collagen that is typical of chronic vascular rejection. In contrast, the coronary arteries in our patients had a prominent lymphocytic infiltrate, a loosely organized intimal thickening composed of smooth muscle cells, and extensive endothelial injury. We believe that these changes define acute vascular rejection of the coronary artery. In 14 transplanted hearts obtained consecutively, at autopsy or at a second transplant procedure, graft failure was caused by acute coronary vascular rejection in six cases and by chronic coronary vascular rejection in one case. The remaining seven patients showed no evidence of vascular rejection and died primarily of sepsis. Cytomegalovirus (CMV) disease was present in 6 of 7 patients with vascular rejection, of which 43% were CMV-negative recipients of hearts from CMV-positive donors. The adoption of a triple-drug protocol, in which azathioprine was added to cyclosporine and prednisone, reduced the incidence of acute vascular rejection from 27% to 8%. We conclude that acute coronary vascular rejection may be initially seen as global cardiac ischemia in the absence of significant interstitial myocardial rejection. Further, acute vascular rejection should be pathologically distinguished from chronic vascular rejection, although both are probably stages in the natural history of immune-mediated vascular injury.

Acute Disease↗