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Biomedical subjects

M B Pliam

Publications and source records attributed to M B Pliam.

At least 19 recordsLinked to original sources

Mitral valve surgery via a right anterior mini-thoracotomy with central aortic cannulation and no endoscopic assistance.

BACKGROUND: A variety of techniques have been described to reduce surgical access in mitral valve surgery: Mini-sternotomy (Gundry) involves partial division of the sternum while the right anterior mini-thoracotomy approaches described involve either Port Accesstradmark; (Heartport, Redwood City, CA), indirect endoscopic techniques (Chitwood) and more recently, robotic techniques (Intuitive Surgicaltradmark;). This report describes a simplified approach that "borrows" aspects from several techniques. METHODS: Using currently available technology, a simplified technique to perform mitral valve surgery (MVST) has been developed. MVST eliminates the need for endoscopic assistance and femoral arterial cannulation. The results of 50 of these patients were analyzed and compared with those of 66 patients who had isolated mitral valve surgery via a conventional approach (MVCS) over the same five-year interval. RESULTS: Between January 1, 1995 and December 31, 2000, 50 patients had mitral valve surgery performed with a simplified technique (MVST). Twenty-six (52%) of the MVST patients underwent mitral valve replacement and 24 (48%) underwent mitral valve repair. There were no in-hospital deaths in the MVST group, compared to a death rate of 7.1% in the MVCS group. There were no strokes and no perioperative myocardial infarctions in the MVST group. Average ICU stay was 3.4 days (1 day shorter than the MVCS group) and average hospital stay was 8.1 days, which was significantly less than the 12.5 day length of stay for the patients having MVCS (p<0.01). Blood was utilized in 36% of the MVST patients, compared to a 55% rate in the MVCS group. There were no wound infections in the MVST group. Two patients did develop bloody effusions requiring thoracentesis. Antegrade blood cardioplegia was used in 35 (70%) of the MVST patients. Antegrade and retrograde blood cardioplegia was used in 15 (30%) patients. Average cross-clamp time in the MVST group was 70 minutes compared to 85 in the MVCS group (p<0.05) and the average pump run was 98 minutes in the MVST group compared to 112 for the MVCS group (p=0.08). CONCLUSION: Mitral valve surgery using a simplified, less invasive technique can be successfully and safely performed in selected patients, resulting in less blood utilization and shorter hospital length of stay, with a cosmetic result that rivals that of robotically assisted techniques.

Catheterization↗

Multiple coronary artery bypass via mini left thoracotomy with conventional aortic occlusion.

BACKGROUND: Complete myocardial revascularization can be achieved through a mini left anterior thoracotomy. Our approach (West Coast Technique) takes advantage of the Port-Access (Heartport, Redwood City, CA) concept while utilizing conventional instrumentation. METHODS: Thirty-eight patients underwent multiple coronary artery bypass grafting (CABG). Aortic occlusion was performed using a transthoracic clamp, and all anastomoses were performed under a single cross-clamp. RESULTS: There were no deaths and no neurologic deficits. There was one perioperative myocardial infarction (MI), and one re-exploration for bleeding. Ten patients (26%) required blood transfusions, and five patients (13%) developed atrial fibrillation. The average number of grafts per patient was 2.9, and average hospital stay was 5.2 days. CONCLUSION: Multiple CABG can be accomplished safely through a minithoracotomy, which eliminates the need for endoaortic occlusion.

Aged↗

Recent improvement in results of coronary bypass surgery in octogenarians.

BACKGROUND: Because of concerns regarding the cost-effectiveness of coronary artery surgery in patients 80 years and older, a review of a large experience is appropriate. METHODS: The records of 404 consecutive patients 80 years of age or older having isolated coronary bypass surgery (CABG) from 1985 through 1996 were reviewed. Patients were divided equally into an early and later group. Hospital mortality, complications including major arrhythmias, wound infections and separations, re-explorations, peri-operative Q-wave myocardial infarctions, major organ dysfunction, stroke, time to extubation, post-operative hospital (LOS) and intensive care unit (ICU) lengths of stay were compared. A logistic regression risk model was used to assess the relative contributions of improved technique versus more favorable patient selection. RESULTS: Comparison of the two groups revealed the following: overall hospital mortality decreased from 12.9% to 5.4% (p = 0.003), more markedly so with elective procedures where hospital mortality decreased from 8.1% to 1.2% (p = 0.04). There were significant decreases in time to extubation (2.8 +/- 9.3 days versus 1.2 +/- 2.8 days; p = 0.02), post-operative intensive care unit stay (4.9 +/- 7.1 days versus 2.9 +/- 3.7 days; p = 0.0004), post-operative complication rate (34.2% versus 22.8%; p = 0.03), and post-operative hospital length of stay (14.2 +/- 14.7 days versus 9.8 +/- 9.8 days; p = 0.0005). Post-operative stroke decreased from 7.4% to 5.9%. Mean estimated risk for the two groups was 8.2 +/- 10.2% versus 8.2 +/- 11.4%. CONCLUSION: Coronary surgery can be performed with acceptable risk in octogenarians. Results have improved over the past few years. This improvement is probably not attributable to patient selection.

Aged↗

Arterial conduits in emergency coronary artery surgery.

The internal thoracic artery (ITA) is considered to be the conduit of choice for coronary bypass (CABG), but there has been some reluctance to utilize the ITA for revascularization in emergency situations. In a 9-year retrospective analysis from 1986 through 1993, 484 patients had emergency CABG, 237 were not associated with failed PTCA (noninstrumented) and 247 were within 24 hours of PTCA (instrumented). About 62% of noninstrumented and 49.3% of instrumented patients received one or more ITA grafts, the others receiving only saphenous vein grafts (SVGs). Those who received an ITA graft tended toward male sex, better ejection fraction, and a generally lower clinical risk score. Instrumented patients tended toward a lower incidence of diabetes and left main coronary disease, higher ejection fraction, and lower clinical risk score than noninstrumented patients. The postoperative results were not significantly different between ITA and SVG groups with respect to new Q waves, need for reexploration, sternal wound infection, respiratory complications, or stroke. However, ITA patients more often had an event-free postoperative course, received fewer blood transfusions, and experienced fewer cardiac deaths (2.7% vs 9.4%, p < 0.01). There were few obvious differences in postoperative results between instrumented and noninstrumented patients. These results indicate that the ITA can be used for emergency CABG in selected patients with good results.

Aged↗

Pituitary adenomas complicating cardiac surgery: summary and review of 11 cases.

From the literature and our own experience, 11 cases of hemorrhage or infarction of a pituitary adenoma associated with cardiac surgery have been identified over a 13-year period. Males outnumbered females by 10 to 1. Symptoms observed were headache, lethargy, confusion, obtundation, unilateral ptosis, meiosis, and opthalmoplegia involving cranial nerves III, IV, and VI, visual field deficits, and hemiparesis. Diagnosis in most recent cases has been confirmed with computerized tomography or magnetic resonance imaging. All patients received adrenocortical steroid therapy initially. Eight patients underwent transsphenoidal hypophysectomy and all survived. One patient underwent decompression craniotomy and died. Intracranial surgery was deferred in 1 patient who survived and in another who died of a massive stroke. Residual neurological deficits were noted to be either absent, minimal, or resolving in 7 of the 9 patients who survived their initial hospitalization. While numerous mechanisms have been proposed to explain the hemorrhage and necrosis of a pituitary adenoma during heart surgery, no direct cause has been clearly identified. Surgical treatment is commonly necessary since untreated pituitary apoplexy is often fatal. Transsphenoidal hypophysectomy with decompression is the preferred method of treatment with a low perioperative mortality and fairly good long-term prognosis.

Adenoma↗

Retrocaval routing of the right internal thoracic artery.

Enhanced use of the right internal thoracic artery affords further opportunity for myocardial revascularization using predominantly arterial conduits. High proximal dissection and routing of the right internal thoracic artery behind the superior vena cava can sometimes allow additional length to the right internal thoracic artery pedicle to facilitate the grafting of posterior and lateral coronary arteries via a less circuitous, more protected route.

Humans↗

Intramyocardial dissecting hematoma: an unusual form of subacute cardiac rupture.

Intramyocardial dissecting hematoma following myocardial infarction is an unusual form of subacute cardiac rupture that tends to develop along naturally occurring dissection planes between the spiral muscles of the ventricle. The diagnosis has commonly been made at surgery, postmortem examination, or by echocardiography. Most are associated with acute transmural inferior infarction. Few patients survive without surgical intervention. Fourteen cases have appeared in the literature. One additional case is described. Ten cases were treated medically with one survivor (10%). Five cases were treated surgically with five survivors. Surgical treatment of intramyocardial dissecting hematoma is preferable to medical treatment. Proper and timely diagnosis and prompt surgical treatment are necessary before complete myocardial rupture ensues. Diagnosis is facilitated through the use of two-dimensional echocardiography. Successful surgical management of this condition requires an appreciation of commonly associated pathoanatomical conditions, and the utilization of appropriate methods of repair in the presence of potential ventricular septal and ventricular free wall rupture.

Aged↗

Right atrial ball-valve thrombus: a complication of central venous alimentation in an infant. Diagnosis and successful surgical management of a case.

The following is a case report of a 6-week-old premature infant in whom a ball-valve thrombus developed after prolonged central venous alimentation. Clinical presentation included facial edema, cyanotic episodes, and apnea. No murmur was present, but the diagnosis was suspected when a calcified right atrial mass became apparent on the plain chest film. The diagnosis was confirmed by echocardiography and then venous and cardiac angiography. The calcified thrombus was removed successfully from the right atrium by use of profound hypothermia with ether anesthesia and total circulatory arrest. Subsequently, the patient made an uneventful recovery and is healthy 3 years postoperatively.

Calcinosis↗

Factors affecting overdrive suppression of idioventricular pacemakers and associated potassium shifts.

A characterization of the factors controlling overdrive suppression of idioventricular pacemakers was investigated in canine hearts with complete atrioventricular block perfused in vitro. The following results were obtained: 1) overdrive suppression increases as a function of driving rate in a sigmoidal fashion; 2) overdrive suppression is maximal after 3 min; 3) the pause is a function of spontaneous rate prior to overdrive; 4) overdrive causes an initial net K loss; 5) overdrive is followed by a transient net K grain; 6) increasing [K]o does not affect K loss; 7) net K loss with drive is less in pre-driven hearts; 8) net K uptake after overdrive is little affected by ventricular activity; 9) acetylcholine does not alter ventricular K balance; and 10) paired stimulation increases overdrive suppression and K loss whether or not each stimulus is followed by a contraction. The following conclusions are drawn. The factors controlling overdrive suppression include the spontaneous rate prior to drive, the rate, duration and pattern of drive, an increase in [K]o during the drive and a decrease in [K]o after drive, but not on acetylcholine-mediated inhibition.

Acetylcholine↗

Retrograde perfusion as a method for myocardial revascularization.

Retroperfusion of the superficial coronary venous system was studied in 44 canine fibrillating in vivo, normothermic preparations, with exclusion of the systemic circulation using cardiopulmonary bypass techniques in order to assess its value as a method of myocardial revascularization. Perfusion of either the isolated aortic arch via a brachiocephalic cannula or of the coronary sinus through the free end of a vein anastomosed to the atrial rim of the sinus was performed for 1 h at 100 cm3/min in groups II-IV following 30 min of anoxia. Oxygen uptake, vascular resistance, venous outflow and venous enzyme levels (CPK, GDH) were studied. Group I controls (antegrade perfusion, no anoxia) showed continued aerobic metabolism in contrast to group II (antegrade perfusion) and III (retrograde perfusion) which displayed negative lactate balance. Oxygen consumption was greater in group III than II (p less than 0.01) with a higher oxygen extraction in III (p less than 0.005). Group IV, which was given intravenously 30 mg/kg methylprednisolone prior to anoxia and then retroperfused, showed continued aerobic metabolism with low GDH venous levels and adequate oxygen consumption. Three dogs were then subjected to aortoatrial rim coronary sinus vein grafts with ligation of the left common coronary artery at its bifurcation with distal left circumflex and anterior descending artery-internal mammary vein anastomoses for venous drainage. The right coronary artery was left intact. Arterial inflow into the coronary sinus was associated with a left ventricular pressure of 70-80 mm Hg for up to 1.5 h while regular sinus rhythm was maintained. We conclude that retroperfusion of the coronary sinus represents a surgically feasible technique for providing oxygen delivery to the ischemic myocardium.

Animals↗

Further evaluation of total pancreatectomy.

The results of 64 total pancreatectomies performed at the Mayo Clinic between 1942 and 1973 have been reviewed. Improvement in recent results as compared to the previously reported series is probably related to improvements in operative techniques and in selection of patients with more favorable malignant lesions. The recent results are more favorable than those reported for a group of comparable patients undergoing standard Whipple procedures for malignant lesions at this institution. Diabetes was easily managed in 76% of patients. Hypoglycemia due to insulin sensitivity is the major problem, and ketoacidosis seldom occurs. Recognition of this has resulted in better management of diabetes with relatively small doses of insulin. The sequels of long-standing diabetes do not appear to be a problem. Gastrointestinal tract hemorrhage has been greatly decreased through the use of more extensive gastric resection.

Adenoma, Islet Cell↗

Conventional splenorenal shunts. A reconsideration.

From 1961 to 1971, 73 central splenorenal and 66 portacaval shunts were done for cirrhotic patients who had bled from esophageal varices. Comparative analysis revealed low (3% and 2%, respectively) operative mortality for elective operations, equal (93%) effectiveness in control of variceal bleeding, but substantial diferences in the incidence of postshunt encephalopathy. For patients who had mimal hepatic dysfunction before operation, disabling disorders in mentation developed in 5% of patients who had splenorenal shunts, in contrast to 50% of patients who had portacaval shunts. Survival rates after the two shunts were nearly identical. Thus, the advantages of splenorenal shunts concern the quality of life but not the length of survival. These observations are considered in relation to available therapeutic alternatives.

Activities of Daily Living↗

Failure of transfusion of autologous whole blood to reduce banked-blood requirements in open-heart surgical patients.

Although transfusion of autologous blood by the method described would seem to be a safe and proctical means of reducing banked-blood requirements for open-heart operations, our experience indicates that the amount of blood needed to be added to the pump oxygenator more than negates the value in reducing intraoperative blood requirements. In fact, autologously transfused patients used more blood than did control subjects. Platelet and fresh-frozen plasma administration was not significantly different for the autologous transfusion or control group.

Blood Banks↗