Search PubMed⌕ Search

Biomedical subjects

A S Geha

Publications and source records attributed to A S Geha.

At least 55 records · Page 3Linked to original sources
PubMed1987

Thoracic surgery manpower: the fourth manpower study of thoracic surgery: 1985 report of the Ad Hoc Committee on Manpower of The American Association for Thoracic Surgery and The Society of Thoracic Surgeons.

Responding to a survey about their practice in 1985, 2,969 (70%) Board-certified thoracic surgeons provided data that were compared with data from manpower surveys in 1980 and 1976. (table; see text) Thoracic surgeons were most active between ages 35 and 54 years when they accomplished 61% of all general thoracic and 85% of cardiac operations. Surgeons older than 50 years performed significantly more general thoracic operations than younger surgeons, and the younger group performed significantly more cardiac operations than their older counterparts. Solo practice continued to decline. In smaller referral areas, the number of general thoracic procedures per surgeon increased, but the number of cardiac operations have decreased compared with 1980. Overall, general thoracic and cardiac operations increased, but peripheral vascular procedures and pacemaker insertions decreased in almost all nine census regions. Fewer general thoracic and cardiac operations were performed per thoracic surgeon in the western United States than in central and eastern regions. In response to questions about work load, 55% believed that their clinical activity was satisfactory, 42% operated too little, and 3% operated too much. The 363 non-Thoracic Board-certified surgeons who responded performed 14% of general thoracic and 8% of cardiac surgery in 1985. During the first half of the 1980s, our specialty certified an average of 134 thoracic surgeons annually, which is higher than the 120 surgeons per year estimated to meet the projected demand.

Adult↗
PubMed1987

Depressed antigen presentation function and membrane interleukin-1 activity of peritoneal macrophages after laparotomy.

Although major tissue trauma produces profound depression of cell-mediated immunity, it is not known whether surgical trauma (i.e., midline laparotomy) has any adverse effect on the antigen presentation function and membrane interleukin-1 (IL-1) activity of peritoneal macrophages. To study this, C3H/HEJ (endotoxin-tolerant) mice were anesthetized. An approximately 1-inch midline abdominal incision was made, followed by abdominal closure. On days 1, 3, 5, and 7, peritoneal macrophages were harvested by means of peritoneal lavage, and antigen presentation capability was tested by incubating various numbers of peritoneal macrophages with 2 X 10(4) D10.G4.1 cells per well in the presence of conalbumin (400 micrograms/ml). The T helper cell clone (D.10.G4.1) proliferates on recognition of conalbumin in the context of Iak and also proliferates in the presence of membrane-bound IL-1 plus concanavalin A. To measure membrane IL-1 expression in peritoneal macrophages, Concanavalin A (10 micrograms/ml) was substituted for conalbumin. Cultures were incubated for 72 hours, pulsed with tritiated thymidine, and harvested. Peritoneal macrophages from laparotomized mice induced significantly less T helper cell proliferation on days 1 and 3 in the antigen presentation assay (37% and 30%, respectively; p less than 0.05) and in the membrane IL-1 assay (14% and 10%, respectively; p less than 0.05) as compared with the control. This difference was not detectable on day 5. More effective antigen presentation capability (167% of control; p less than 0.05) was seen on day 7. Thus laparotomy by itself produces marked depression of both antigen presentation function and membrane IL-1 activity of peritoneal macrophages, which may enhance susceptibility to intra-abdominal sepsis.

Animals↗
PubMed1987

Long-term outcome of revascularization of the anterior coronary arteries with crossed double internal mammary versus saphenous vein grafts.

When simultaneous revascularization of the left anterior descending (LAD) artery and the proximal segments of the diagonal LAD and marginal coronary arteries is required, the direction and location of these vessels allow excellent alignment of the left internal mammary artery (IMA) with the LAD and the right IMA with the diagonal LAD or marginal arteries, an approach originally described in 1976. To analyze and compare the long-term outcome of this approach versus the saphenous vein bypass graft (SVG) approach for anterior coronary revascularization, we reviewed 43 patients who had these crossed double IMAs (CDIMAs) and 53 patients who had SVGs to the same obstructed anterior coronary arteries during 1973 to 1978; 32 patients in the CDIMA group and 43 in the SVG group also had SVGs to other diseased vessels. The two groups had similar demographic and epidemiologic characteristics. The linearized incidence of late cardiac death, reoperation, recurrent angina, and infarction was 0.2%, 0.7%, 1.4%, and 0% per patient-year, respectively, in the CDIMA group, and 1.6%, 2.4%, 7.8%, and 1.8% per patient-year in the SVG group (p less than 0.01 for each event). At 5 years, the actuarial number of patients with CDIMAs free of late cardiac death was 100%, of reoperation 98%, of recurrent angina 98% (p less than 0.01), and infarction 100% (p less than 0.01), versus 94%, 98%, 84%, and 94%, respectively, in the SVG group. At 10 years, the actuarial incidence of all events was substantially and significantly less in patients with CDIMAs. CDIMAs have significantly better prognostic effects than SVGs when revascularization of the anterior coronary arteries is required. This is currently our preferred approach in these selected patients.

Actuarial Analysis↗
PubMed1987

Long-term performance of the St. Jude Medical valve: low incidence of thromboembolism and hemorrhagic complications with modest doses of warfarin.

Between January 1980 and April 1986, 204 patients were hospital survivors after aortic, mitral, or double valve replacement with the St. Jude Medical valve. One hundred ninety patients underwent anticoagulation with modest doses of warfarin (Coumadin), with prothrombin times in the range of 1.3 to 1.5 times control. Fourteen patients received aspirin and dipyridamole only. Follow-up ranged from 0.5 to 6.6 years (mean 3.1) and was 99.5% complete. The group was analyzed for occurrence of thromboembolism, hemorrhage, valve thrombosis, endocarditis, perivalvular leak, valve failure, late cardiac death, and all morbidity and mortality combined in linear and actuarial terms over the 7 year period. With this anticoagulation regimen, the linear rate for thromboembolism and hemorrhage was 0.67% and 1.3% patient-year, respectively, and the actuarial event-free incidence at 5 years was 97.4% and 94.4%, respectively. There were no instances of structural valve failure and one instance of valve thrombosis in the mitral position. Eighty-seven percent of patients were alive at 5 years and 76.7% of patients were alive and free of all complications at 5 years. We conclude that the St. Jude Medical valve has a low incidence of thromboembolism, hemorrhagic complications, and valve thrombosis in patients receiving modest doses of warfarin.

Actuarial Analysis↗
PubMed1987

Biological versus mechanical valves. Analysis of 1,116 valves inserted in 1,012 adult patients with a 4,818 patient-year and a 5,327 valve-year follow-up.

All surviving patients between 18 and 88 years of age receiving biological or mechanical prosthetic heart valves at the Yale-New Haven Hospital from January 1974 through January 1985 were analyzed for thromboembolism, anticoagulation-related hemorrhage, endocarditis, perivalvular leak, valve failure, need for reoperation, late cardiac death, and valve-related death. The rates of these events were analyzed in linear and actuarial terms over the 11 year period. A total of 533 patients received 606 biological valves (328 aortic, 252 mitral, 24 tricuspid, and two pulmonary, consisting of 482 Carpentier-Edwards, 108 Hancock, 15 Ionescu-Shiley, and one other), with a mean follow-up of 2,571 patient-years and 2,935 valve-years. They were compared with 479 patients with 510 mechanical valves (330 aortic, 175 mitral, and five tricuspid, consisting of 178 Starr-Edwards, 166 St. Jude Medical, 164 Björk-Shiley, and two others), which were implanted for 2,247 patient-years and 2,392 valve-years. We found a significantly increased incidence of thromboembolism (p less than 0.001) and reoperation for perivalvular leak (p less than 0.05) in the mechanical valves compared with the biological valves, but a significantly increased rate of valve failure (p less than 0.001) in the biological valves compared with the mechanical valves. The overall analysis comparing total morbidity and valve-related mortality significantly (p less than 0.01) favored the biological valves in the first 5 years of the study and the mechanical valves (p less than 0.001) in the second 5 years of the study. However, the net 10 year results showed no significant difference between the two types of valves. In summary, we found little direct evidence to strongly support the generalized use of one type of valve over another.

Actuarial Analysis↗
PubMed1986

Fate of left-sided cardiac bioprosthesis valves in children.

To avoid anticoagulation and minimize thromboembolic phenomena, between 1975 and 1980 we used 18 porcine bioprosthetic valves (BPVs) to replace 11 aortic and seven mitral valves in 17 children ranging from 7 to 18 years of age (mean, 8.2 years). Ten BPVs (91%) in the aortic position had to be replaced one to six years (mean, 4.2 years) after insertion. Nine of these valves developed severe calcification with leaflet immobility and severe stenosis. The tenth valve became insufficient with a disrupted cusp. Six (86%) of seven BPVs inserted in the mitral position required replacement two to four years (mean, 3.1 years) after insertion. Massive mitral regurgitation developed in three, while in the other three mitral stenosis was prominent. All explanted BPVs exhibited calcification with disruption and loss of mobility of the leaflets. Hemodynamic deterioration often occurred catastrophically, with nine patients requiring emergency valve replacement. Elective valve replacement carried no hospital mortality, whereas emergency valve replacement carried a 33% mortality. The BPV failure rate of 94% within six years leads us to recommend against the use of biologic valves in the pediatric age group in the aortic or mitral position. Bioprosthetic valve failure may occur catastrophically and replacement should be carried out early to avoid the higher operative mortality associated with emergency surgery.

Adolescent↗
PubMed1985

Predictors of outcome in early revascularization after acute myocardial infarction.

We have reviewed 44 consecutive patients undergoing myocardial revascularization from 1 to 42 days after myocardial infarction. Operation within 12 days of transmural myocardial infarction carried a substantially high risk, particularly in patients with poor ventricular function. Patients with subendocardial infarction may be safely operated on shortly after infarction has occurred. In those with transmural infarcts, it may be advantageous to delay operation if early and aggressive medical therapy can effectively control the symptoms. This has to be counterbalanced, however, by the realization that the situation should not be allowed to slide into one of irreparable ventricular damage from infarct extension.

Female↗
PubMed1985

Measurement of central somatosensory conduction time in patients undergoing cardiopulmonary bypass: an index of neurologic function.

It is feasible to monitor somatosensory evoked potentials and central somatosensory conduction times during open heart surgery and cardiopulmonary bypass with moderate or profound hypothermia. Central conduction times are reproducible, have acceptably low interpatient and intrapatient variability, and are not significantly affected by fentanyl-induced anesthesia. There is a predictable logarithmic relationship between central conduction times and temperature with the central conduction time increasing by 6.6 percent for a 1 degree C decrease in temperature. These data indicate that somatosensory conduction times may be a useful index of central nervous system integrity during open heart surgery that utilizes cardiopulmonary bypass and hypothermia.

Adult↗
PubMed1984

Noncardiogenic pulmonary edema after cardiopulmonary bypass. An anaphylactic reaction to fresh frozen plasma.

Nine episodes of fulminant noncardiogenic pulmonary edema after cardiopulmonary bypass were observed in eight patients between September 1977 and December 1982. All these catastrophic reactions occurred during administration of fresh frozen plasma 30 minutes to 6 hours after discontinuation of cardiopulmonary bypass. In one patient, two episodes of noncardiogenic pulmonary edema occurred 4 hours apart. In each instance, fresh frozen plasma was being administered. In all patients, pulmonary artery diastolic pressure became elevated during the administration of fresh frozen plasma while left atrial pressure or pulmonary capillary wedge pressure progressively decreased, and cardiac output deteriorated markedly in all but one patient. Corticosteroids, positive end-expiratory pressure, and catecholamines were administered to all patients. All deaths were due to a decrease in cardiac output. Cardiac output did not increase substantially with the use of an intraaortic balloon pump or the administration of catecholamines. The last two patients in the series showed a steady and remarkable improvement in cardiac output when the wedge pressure was increased to a level above 15 mm Hg with the administration of normal saline solution. Our data suggest the following: (1) noncardiogenic pulmonary edema after cardiopulmonary bypass is most probably an anaphylactic reaction to fresh frozen plasma. (2) The syndrome is reversible within hours; in only one patient (who suffered noncardiogenic pulmonary edema twice) did adult respiratory distress syndrome develop. (3) The three deaths were not related to hypoxia but to the deleterious effects of low cardiac output associated with hypovolemia secondary to fluid loss through the lungs and possibly across other capillary beds. Therefore, treatment should include restoration of adequate left-sided filling pressures to achieve satisfactory cardiac output.

Adolescent↗
PubMed1984

Combined valve replacement and myocardial revascularization.

Combining valve replacement with coronary artery bypass (CABG) for significant concomitant disease remains a controversial subject. To determine the operative results following combined valve replacement and CABG, we evaluated 201 patients seen consecutively between July 1977 and June 1982. CABG for vessels with greater than 70% stenosis was performed with aortic valve replacement in 106 patients, with mitral valve replacement in 82, and with aortic and mitral valve replacement in 13. There were 143 men and 58 women; the mean age was 67 years. Nine operative deaths (8.5%) occurred with aortic valve replacement and CABG: 5 of 25 (20%) when cardioplegia was not used and 4 of 81 (4.9%) with cardioplegia (p less than 0.01). The operative mortality rate for isolated aortic valve replacement without coronary disease during the same period was 5.9% (10 of 168). The late actuarial survival rate is similar for aortic valve replacement alone or aortic valve replacement and CABG. There were no operative deaths among patients having undergone aortic and mitral valve replacement and CABG; the rate was 15% (9 of 60) in patients having undergone aortic and mitral replacement and CABG. The operative mortality rate was 21.9% for mitral valve replacement and CABG (18 of 82). Rheumatic disease was present in 14 of these patients, two of whom had early deaths (14.3%), both after repeat mitral operations; 11 mitral valve replacements and CABG were done for degenerative mitral regurgitation with no deaths, and the remaining 57 patients had ischemic mitral regurgitation.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1983

Optimal methods of repair of descending thoracic aortic transection and aneurysms.

The method for optimal protection of the spinal cord and viscera during surgical repair of aneurysms and acute disruptions of the descending thoracic aorta is controversial. We reviewed our experience with 50 consecutive patients who underwent such repairs between January 1968 and April 1982 to determine the safest method of protection. Thirty-two had acute transections, 9 had ruptured aneurysms, 6 had false aneurysms, and three had atherosclerotic aneurysms. Extracorporeal circulation was used in 21 patients with an average cross-clamp time of 67 minutes, a Gott shunt was used in 26 with an average cross-clamp time of 74 minutes, and no shunt was used in 3 patients with cross-clamp times of 20, 24, and 50 minutes. Paraplegia was significantly reduced with both extracorporeal circulation and the heparin-bonded Gott shunt; however, the former method was associated with a high incidence of postoperative bleeding in conjunction with systemic heparinization, and this, in turn, contributed to a high mortality, particularly in patients with traumatic transection who often had associated severe injuries. We believe that the Gott shunt provides the best protection, particularly in the setting of a training program where a relatively small number of these operations are performed and cross-clamp times may be prolonged.

Adolescent↗
PubMed1983

Extraanatomical reconstruction for bilateral intrathoracic subclavian artery aneurysms.

Successful extraanatomical repair of bilateral intrathoracic arteriosclerotic subclavian artery aneurysms is reported. Rupture of the left subclavian aneurysm required emergency thoracotomy for proximal and distal ligation. The right subclavian aneurysm was repaired electively. Because of constraints resulting from the arterial anatomy (origin of aneurysm at innominate artery bifurcation), prior operation (coronary artery bypass grafting and repair of aneurysm of the sinus of Valsalva), and the patient's occupation (young, employed craftsman with dominant right hand), an extraanatomical reconstruction was devised to exclude the aneurysm and revascularize the head and arm. The reconstruction consisted of an external ilioaxillary Gore-Tex bypass graft in conjunction with an end-to-end distal subclavian to distal common carotid Gore-Tex graft. This is believed to represent the first reported successful repair of bilateral intrathoracic arteriosclerotic subclavian aneurysms, and the first application of this extraanatomical reconstruction.

Aneurysm↗
PubMed1982

Implantation of permanent transvenous pacemaker via subclavian vein.

A favorable overall experience was found with permanent transvenous cardiac pacing using a direct venipuncture for entry into the subclavian vein. The method allows a rapid and relatively atraumatic introduction of a variety of transvenous pacemaker electrodes. However, a fatal complication developed that was caused by unrecognized puncture of the left pulmonary artery in an elderly patient. This was the result of a technical error and emphasizes that experience in subclavian venipuncture is essential to avoid the complications of this approach.

Aged↗
PubMed1982

Continuous monitoring of left ventricular performance with the computerized nuclear probe during laryngoscopy and intubation before coronary artery bypass surgery.

Left ventricular performance was monitored serially in 25 patients during laryngoscopy and intubation in the anesthetic induction period before elective coronary artery bypass surgery using the labeled equilibrium blood pool and the computerized nuclear probe. Left ventricular ejection fraction was obtained preoperatively, after induction of anesthesia but before endotracheal intubation, immediately after intubation, and at 1 minute intervals thereafter for 10 minutes. In all patients, there was an immediate decrease (mean 16%) in left ventricular ejection fraction accompanying the reflex hypertension and tachycardia occurring during laryngoscopy and endotracheal intubation; it was significantly depressed for 3 minutes with the concomitant hemodynamic changes. Seven patients did not demonstrate a recovery of left ventricular ejection fraction to the preintubation value. In 10 healthy noncardiac patients undergoing orthopedic surgery, after an identical anesthetic induction sequence and intubation, there was a similar decrease in ejection fraction, but of shorter duration. In these patients the recovery of left ventricular performance preceded the recovery of blood pressure and heart rate. This study demonstrates that profound decreases in left ventricular performance accompany the reflex hypertension and tachycardia occurring during endotracheal intubation and that there is persisting depression of left ventricular function in some patients with coronary artery disease. These findings indicate the potential utility of the computerized nuclear probe for monitoring ventricular performance during this critical period.

Adult↗
PubMed1982

Changing patterns in the surgical management of ventricular septal rupture after myocardial infarction.

Seventeen consecutive patients who underwent repair of postinfarction ventricular septal rupture between 1975 and 1980 at the Yale-New Haven Medical Center are reported on. The most important prognostic indicator of a favorable outcome was the patient's preoperative hemodynamic state. The mortality rate ranged from 83 percent for patients in shock to no mortality in patients with mild to moderate symptoms. There was a strong tendency for hemodynamic deterioration despite hemodynamic support with pharmacologic agents as well as intraaortic balloon pumping. Our review indicates that several patients might have been saved if operation had been performed earlier. Based on this experience and that of others, a management plan is formulated, and we recommend early surgical intervention in all operable patients with ventricular septal rupture. In patients with severe cardiogenic shock, we forego full cardiac catheterization, confirming the diagnosis by an oxygen step-up in the pulmonary artery only. These patients undergo operation on an urgent basis. No undue technical difficulties were related to early operation. At present, maximum survival of patients with postinfarction ventricular septal rupture may be accomplished by early surgical intervention in all operable cases.

Aged↗
PubMed1982

Radionuclide assessment of left ventricular function in patients requiring intraoperative balloon pump assistance.

Twenty-three surviving patients who were weaned from cardiopulmonary bypass with intraaortic balloon pump assistance returned for follow-up radionuclide left ventricular (LV) function and thallium 201 perfusion studies at a mean of 23 +/- 3 months following operation. It was found tat despite profound intraoperative myocardial depression requiring intraaortic balloon assistance, 13 patients had no change (within 10%) in the resting LV ejection fraction compared with the preoperative measurement. Among all 23 patients, there was no difference between mean (+/- standard error of the mean) preoperative and postoperative resting LV ejection fraction (48 +/- 4 vs 46 +/- 4%, p = not significant [NS]). Only 11 patients had perioperative myocardial infarction documented by new Q waves in the electrocardiogram, by elevation of creatine kinase-MB fraction, or by defects on thallium 201 imaging not explained by documented myocardial infarction before operation. Overall, postoperative resting LV ejection fraction was not different from the preoperative value in patients with perioperative myocardial infarction (44 +/- 7 vs 47 +/- 5%, p = NS). Postoperative resting LV ejection fraction rose by greater than 10% compared with preoperative values in 4 patients (3 with aortic valve replacement), remained within the 10% limit in 9 patients, and fell by greater than 10% in 10 patients (7 with perioperative myocardial infarction). Only 4 out of 16 patients studied at follow-up with exercise radionuclide studies demonstrated a normal LV response to exercise (greater than 5% increase in LV ejection fraction). Thus, among survivors requiring intraaortic balloon pump assistance for weaning from cardiopulmonary bypass, LV performance at rest is frequently preserved. In addition, 11 of the 23 patients had evidence of perioperative myocardial infarction, indicating a component of reversible intraoperative LV dysfunction.

Adult↗