Biomedical subjects
Publications and source records attributed to R Zajtchuk.
A case of primary pericardial malignant epithelioid mesothelioma had an unusual presentation and emphasizes the urgency and possibility of antemortem diagnosis. Postmortem findings with electron microscopic studies document its histologic origin.
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Eighty patients underwent isolated mitral valve replacement with the Kay-Shiley prosthesis during a 6 year period (September, 1966, in October, 1972) at Walter Reed Army Medical Center. One-hundred percent follow-up has been achieved with this group. Sixty-four percent of this group have experienced one or more thromboembolic episodes (TEEs), for a TEE rate of 28.7 episodes per 1,000 patient months at risk. The 5 year survival rate is 45%. Eleven of 43 (25%) late deaths resulted from TEEs, and 13 of 43 (30%) late deaths were secondary in the hemorrhagic complications of long-term anticoagulant therapy. The dismal TEE rate prompted as to initiate a policy of elective replacement of all Kay-Shiley mitral prostheses. Eighteen of the 26 survivors underwent replacement of the Kay-Shiley mitral prosthesis. The other eight patients either declined reoperation or were not considered suitable candidates. The reoperative mortality rate was 22% (4/18). Fifteen of 18 explained prostheses revealed a yellow disclored, grooved occluder disc with loosely adherent clot. We recommend elective replacement of Kay-Shiley mitral prostheses in all patients in whom the risk of operation is reasonable.
Thirty-one patients treated for isolated intrathoracic ganglioneuroblastoma have been evaluated. The surviving patients (27/31) have been followed for periods up to 25 years. The modes of treatment consisted of complete or partial resection of the tumor, radiation therapy, or chemotherapy. Analysis of the data revealed that four patients treated with radiation alone died within 3 months after the start of treatment. Two patients had complete removal of the tumor without adjuvant therapy. Each is free of recurrent disease at 10 and 11 years postoperatively. The other 25 survivors had complete or incomplete surgical resection followed by radiation and/or chemotherapy. All are free of recurrent disease. Of the 25 patients who received postoperative radiation, 11 developed moderate-to-severe skeletal deformity. There appeared to be a correlation between deformity and the dose of radiation. Our current treatment recommendation consists of immediate operative intervention with an attempt at complete removal of the tumor. Patients with incomplete removal of tumor should be treated with radiation (2,000 r). Chemotherapy consisting of methotrexate or a combination of cyclophosphamide (Cytoxan) and vincristine should be reserved for patients with distant metastasis.
There is a tendency to equate left main (LM) and left main equivalent (LME) coronary artery disease in terms of the surgical risk and benefit. Eighty-seven patients with LM disease were compared to 78 patients with LME disease as to operative mortality rate and long-term benefits. One hundred percent follow-up was obtained. Although the two groups were similar preoperatively with regard to age, sex, and ventricular function, the operative results in the two groups differed. There was a significantly higher operative mortality rate in the LM group of patients (12.6% versus 2.5%). However, the incidence of graft patency and relief of symptoms was lower in the LME group of patients. The late mortality rate was 4% in both groups. LME disease appears to represent a subgroup of patients with three-vessel disease and cannot be equated with LM disease.
Standard management of median sternotomy dehiscence sometimes fails to achieve lasting reduction and fixation of the sternal halves. An effective method of external thoracic traction that augments internal fixation of the sternal fracture is presented.
One hundred patients were screened for hypercoagulability preoperatively and on the third, seventh, tenth, fourteenth, and twenty-first days postoperatively. Patients found to have hypercoagulability were treated with heparin, aspirin, and Coumadin. When the abnormality was present preoperatively, treatment was continued for the duration of the patient's life. Those patients in whom abnormalities developed postoperatively were given anticoagulants until cardiac catheterization 6 months following their operation. Twenty-four of the 100 patients had no coagulation abnormalities preoperatively or postoperatively. Fifteen patients were found to have abnormality prior to operation. Their predominant abnormality was low antithrombin III activity. Sixty-one patients became hypercoagulable postoperatively. Predominant abnormality in this group of patients was increased thrombin generation and increased platelet adhesiveness. Evaluation of patients in this study group revealed a decrease in the incidence of pulmonary embolism, an increase in the patency of vein grafts, and the elimination of anticoagulant therapy in 24 percent of the patients.
Neoplasms of the left upper lobe may spread directly to the anterior mediastinal group of nodes without involving the inferior tracheobronchial, superior tracheobronchial, or paratracheal nodal chain. Routine cervical mediastinoscopy does not sample the anterior mediastinal node group. Parasternal anterior mediastinotomy was performed in 28 patients with left upper lobe carcinoma and normal findings from cervical mediastinoscopy. Despite the normal findings at cervical mediastinoscopy, 10 of the 28 patients were deemed to have inoperable disease because of spread of the neoplasm to the anterior nodal group or because of direct neoplastic involvement of the aorta or main pulmonary artery. All patients in whom results of anterior mediastinotomy were normal had resectable lesions at thoracotomy. Fourteen of the 16 patients who came to thoracotomy had normal hilar nodes. Parasternal anterior mediastinotomy, introduced by Chamberlain, should be performed in addition to standard cervical mediastinoscopy if the nodal drainage of left upper lobe neoplasms is to be more completely evaluated. Combining these two procedures samples all major drainage pathways except the posterior mediastinal nodal chain.
There is a tendency toward hypercoagulability in the postoperative period. This is manifested by changes in a number of coagulation parameters, and if not offset by some protective mechanism, thrombosis may occur. This protection appears to be mediated more through the fibrinolytic mechanism than through the action of antithrombin 3 (AT-3) because AT-3 activity diminishes in the early postoperative period. The introduction of variables such as invasion of the vascular system, intraoperative heparin administration, administration of whole blood, and insertion of a Dacron prosthesis does not appreciably affect the response of the coagulation profile to operative stress.
In an effort to evaluate polytetrafluoroethylene (Gore-Tex) as a replacement for large veins, tubular grafts of the material were substituted for the precava in 33 mongrel dogs weighing 15 to 30 kg. Thirteen dogs had grafts 10 cm long by 12 mm wide with a 15-to 30 micron pore size; 15 dogs had grafts of the same length and width from 90-micron pore size material; and 5 dogs had grafts 5 cm long by 12 mm wide, of 90-micron pore size Gore-Tex. The effect of Gore-Tex tubes with and without spiral support and the differences in anatomical positions of the grafts were evaluated in terms of patency. Dogs were killed if a venogram showed occlusion of the graft. Twelve dogs survived 90 days; the longest survivor was killed at eleven months. At postmortem examination, the graft was patent but extremely narrow at the atrial end. Modification in the fabrication of Gore-Tex may eliminate factors contributing to graft failure; experiments longer than 90 days are necessary to evaluate Gore-Tex as a large vein replacement material. The 90-micron pore size material used in this experiment was unsuitable as a canine venous substitute.
We analyzed the long-term results in 87 patients who had pectus deformities repaired at Fitzsimons Army Medical Center during the period 1953 to 1975. Seventy-one patients had operations for correction of pectus excavotum; 16 had pectus carinatum deformities repaired. A variety of surgical techniques was used in these patients. Our findings show that in excavatum deformities the best results were obtained by removing all deformed cartilage, mobilizing the sternum, using an anterior osteotomy, and stabilizing the chest with a metal strut (which was removed after one year). For carinatum defects, the Ravitch procedure has produced good results. We are encouraged to be more aggressive in advocating repair of the deformities, not only for cosmetic results but because the patients seem to feel healthier both physically and mentally after repair. For these reasons we advocate operation for pectus deformity as any age.
Thirty patients in whom all aorta-coronary artery vein grafts became occluded within one year of operation, as demonstrated by cardiac catheterization, were evaluated for hypercoagulability. A total of 59 grafts were constructed in these patients. At operation, blood flows of 35 to 90 c.c. per minute were measured through the grafts. In 23 of the 30 patients, the blood was to be hypercoagulable, as evidenced by a low level of antithrombin III activity, high thrombin generation index, high factor VII values, or high platelet adhesivity. Another group of 11 patients (total number of grafts, 23) had all grafts patent at cardiac catheterization. These patients had flows through the grafts ranging from 20 to 125 c.c. per minute. None of the patients with patent grafts had hypercoagulable blood. The status of runoff was comparable between the patients with open grafts and those with occluded grafts.
The study includes 50 patients with severe, stable angina who have undergone the saphenous vein bypass operation. Patients were evaluated preoperatively and postoperatively with regard to exercise tolerance, incidence of stress-induced agina, ST-segment changes of ischemia, and ventricular function as indicated by stroke work index (LVSWI) and ejection fraction. Comparisons were made between patients with complete revascularization (CR) and patients with postoperative residual ischemia (RI). Results revealed that exercise duration improved significantly in both the CR and RI groups. In the CR group, angina and ischemic ST changes were completely eliminated. In the RI group, there was a 25 percent incidence of stress angina and a 50 percent incidence of ischemic ST-segment changes. In neither group was the ejection fraction significantly different from preoperative values. LVSWI decreased significantly in both groups postoperatively.
Sixteen dogs were studied in an effort to investigate certain peripheral vascular and metabolic parameters in endotoxic shock. Cardiopulmonary bypass was instituted for 12 of the dogs to study systemic parameters at constant circulatory flow rates. From these studies, it appears that endotoxin is capable of initiating profound hemodynamic and metabolic changes. Initially, cardiac output and arterial pressure drop precipitiously, despite a transient rise in systemic and pulmonary vascular resistance. Subsequently, peripheral arterial pressures and systemic vascular resistance continue to decline, even if arterial flow remains at constant levels. Oxygen extraction by peripheral tissues decreases after endotoxin injection, despite adequate oxygen availability and constant hemoglobin levels.
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Fifty-six dogs were used in a study to evaluate perfusion of the left anterior descending vein by the internal mammary artery in hearts with normal coronary arteries and those with ligated desending coronary arteries. Perfusion of the myocardium with arterial blood through the cardiac veins offers minimal immediate protection from infarction, as evidenced by light and electron microscopy studies. This protection is of short duration due to intimal fibrosis and luminal stenosis or obstruction of the perfused veins. Nineteen animals in which the coronary vein was perfused and the corresponding coronary artery was not ligated died within sixty hours from the time of operation. Pathological examination revealed patent grafts in all the animals. There was marked congestion of the myocardium with petechial hemorrhages over the surface of the heart. No evidence of myocardial infarction was found.
Twenty-seven patients with peripheral vascular disease had studies of thrombin generation, antithrombin III -alues, factor VIII values, platelet adhesitivity, and activated partial thromboplastin time. Of the studies performed, the thrombin generation index, antithrombin III values, and, to a lesser extent, activated partial thromboplastin time were reliable in confirming clinically suspected hypercoagulability. When patients were placed into groups with and without operative complications, it was noted that the group with operative complications had higher average values of thrombin generation index and lower average values of antithrombin III and activated partial thromboplastin time than did the group without operative complications. It is thought that these tests may be useful in selecting those patients with a high risk of thrombotic complications from vascular surgery and who may benefit from anticoagulant management while undergoing necessary vascular reconstructive procedures.