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Biomedical subjects

A Starr

Publications and source records attributed to A Starr.

At least 307 records · Page 17Linked to original sources
PubMed1976

A hermetically sealed mercury cell pacemaker: advantages and early clinical results.

Despite the known advantages of hermetic encapsulation of implanted pacemakers, only a few conventionally powered models are totally hermetically sealed, and most of them are not yet clinically available. This report describes the results with a mercury cell unit which has been in clinical use since 1970 and has been totally hermetically sealed since 1974. The lowered premature failure rate with the newer model substantiates the theoretical advantages of hermetic encapsulation. The rate behavior of the pulse generator, upon which our telephone follow-up system is based, is essentially the same for both models.

Heart Diseases↗
PubMed1976

Acute aortic dissection from cross-clamp injury.

Acute dissection of the ascending aorta secondary to cross-clamp injury can be successfully managed if the problem is recognized immediately. Bypass must be instituted after recannulation at a point distal to the innominate artery so that proper exposure of the site of injury can be obtained. Systemic as well as local hypothermia for myocardial preservation are both necessary. Direct suture closure of all layers at the site of dissection over Teflon felt can terminate this process.

Acute Disease↗
PubMed1976

Mitral valve replacement: a 10-year follow-up of non-cloth-covered vs. cloth-covered caged-ball prostheses.

The timing of operation and the selection of prosthesis depend upon the evaluation of long-term results at 5 years and beyond. From 1965 to 1975, 290 patients had isolated mitral valve replacement with currently used prostheses, resulting in a 6.6% operative mortality and 64% relative survival at 10 years. In considering mortality, the results obtained with both series of valves were combined and a search made for significant differences in preoperative variables between the operative deaths and operative survivors. The significant variables for operative mortality were valve model, preoperative functional class, pump time, and the presence or absence of right ventricular hypertrophy on electrocardiography. There were significant differences in long-term survival only with regard to preoperative functional class, pulmonary vascular resistance, and pump time. Exponential curves were fitted to the event-free rates, and long-term results were then extrapolated. The 10-year projection of the percentage of patients alive and free of embolus (disregarding transient ischemic attacks) for the Model 6310-6320 (50%) was similar to that actually observed for the Model 6120 (46%). Although further experience may show one prosthesis more effective than the other, statistical extrapolations suggest continued comparable performance.

Female↗
PubMed1976

A new concept in vesical conduits.

To overcome the problems associated with cutaneous vesicostomies a new concept in vesical conduits was developed and performed in 13 dogs. The principle of the new conduit is the utilization of minimal bladder tissue to create a stoma analogous to that of the ileal conduit and to perform an antireflux vesicoureteral anastomosis. Preliminary results with the animal studies indicate that the vesicostomy's major faults have been successfully surmounted by this new procedure.

Animals↗
PubMed1975

Auditory brain stem responses in neurological disease.

A sequence of seven low-amplitude (nanovolt) potentials that occur in the initial 10 msec following click signals can be recorded from scalp electrodes in human subjects using computer averaging techniques. The potentials, termed auditory brain stem responses, are thought to be the far-field reflection of electrical events originating in the auditory pathway during its course through the brain stem. We have studied auditory brain stem responses in a variety of neurological disorders and found them to be of assistance in evaluating the mechanisms of coma, the localization of midbrain and brain stem tumors, the localization of demyelination of the brain stem, and tumors, the localization of demyelination of the brain stem, and the presence of diminished brain stem circulation.

Acoustic Stimulation↗
PubMed1975

Postoperative hemodynamic and electrophysiologic evaluation of the interatrial baffle procedure.

Hemodynamic and electrophysiologic studies were performed in 11 children with dextrotransposition of the great arteries an average of 26 months after the interatrial baffle procedure and, in 2 patients, additional closure of a ventricular septal defect. All children are clinically well. Right to left shunts ranging from 28 to 63 percent of systemic blood flow were found at the superior vena caval-baffle junction in four children. The superior vena caval-baffle gradient averaged 7 mm Hg (range 0 to 22). Right ventricular stroke work index averaged 39 g-m/beat per m2 and right ventricular end-diastolic pressure 9 mm Hg. These values were not significantly different from the values for the systemic left ventricle in a comparable group of normal children (average left ventricular stroke work index 45 g-m/beat per m2 and average left ventricular end-diastolic pressure 8 mm Hg). Cardiac index, heart rate and arteriovenous oxygen difference were also normal. No child has complete heart block. His bundle recording demonstrated normal H-V intervals (range 27 to 40 msec); 4 of the 11 had a prolonged A-H interval. Left ventricular systolic pressure was less than 40 mm Hg in all but two children who had significant subpulmonary stenosis. Pulmonary vascular resistance averaged 1.9 units and was decreased in all children. We conclude that up to 37 months postoperatively, despite some residual abnormalities, the clinical and hemodynamic condition of these children is excellent.

Angiocardiography↗
PubMed1975

Ball valve prostheses: current appraisal of late results.

Advanced actuarial techniques are used to analyze late results in 912 patients who had isolated mitral or aortic valve replacement with ball valve prostheses from 1965 to 1974. Experience with noncloth-covered and cloth-covered valves is compared in terms of late survival, rate of thromboembolic complications and reoperation and the influence of anticoagulation. The cloth-covered prostheses have substantially reduced the incidence of emboli after mitral valve replacement (1.9 vs. 6 emboli per 100 patient years) and have thus far eliminated emboli after aortic valve replacement in patients receiving warfarin. Patients with a cloth-covered aortic valve who did not receive warfarin had nine emboli per 100 patient years. The safety of cloth-covered valves is clearly enhanced by warfarin therapy; the efficacy of anti-platelet drugs is still uncertain. Strut cloth wear was found at reoperation in 10 patients. This should be prevented in the new model 2400 composite strut ("track") valve by a narrow metal track on the inner surface of each strut. The substantial recent reductions in operative mortality and in prosthesis-related complications pose important questions regarding timing of operations and selection of prostheses. These decisions must be individualized for each patient on the basis of a thorough analysis of late results using modern statistical methods.

Aortic Valve↗
PubMed1975

Left main coronary artery disease. Risks of angiography, importance of coexisting disease of other coronary arteries and effects of revascularization.

To elucidate the determinants of the poor prognosis of patients with left main coronary artery disease and to assess the efficacy of diagnostic and therapeutic interventions the angiographic features and clinical course of 58 patients with left main coronary artery disease studied between September 1967 and June 1974 were analyzed. Eighty-three coronary arteriograms were obtained in these 58 patients using the Judkins technique; there were no immediate complications although one patient died 3 days after study. Previously cited predictors of left main coronary artery, unstable or nonexertional angina and marked S-T segment depression with exercise were found in a minority of patients; thus, the presence of the disease could not reliably be predicted before arteriographic study. Coexisting disease was found in either two or three other coronary arteries in 46 of 58 patients; only 2 patients had isolated left main coronary artery disease. Because the criteria for operability have changed in recent years, current criteria without knowledge of the treatment actually given or its outcome. The condition of 10 of 58 patients was judged inoperable in retrospect because of severe coexisting distal coronary artery disease (8 patients) or ventricular dysfunction (2 patients). Of 19 patients whose condition was judged operable in retrospect but who were treated without surgery, 9 died, 8 within 18 months; 10 have survived 12 to 83 months. Another 27 patients with a condition judged operable in retrospect had received saphenous vein bypass grafts. In this group, there were four operative and three late deaths. The severity of angina decreased in survivors treated surgically but was unchanged in survivors treated without surgery. The improvement in survival rates of surgically treated patients was not statistically significant. The data indicate that coronary arteriography can be performed at low risk with the Judkins technique even though preangiographic prediction of left main coronary artery disease is unreliable. Coexisting disease in oter major coronary arteries is an important determinant of the poor prognosis of patients with left main coronary artery disease and precludes surgery in 13 percent. Isolated left main coronary artery disease is uncommon. Surgical therapy relieves symptoms more effectively than nonsurgical therapy.

Angina Pectoris↗
PubMed1975

"No-vent" technique of coronary artery bypass.

Isolated coronary artery bypass grafting was performed in 100 patients without the use of a left ventricular vent. Distention of the left ventricle did not occur. There was 1 late death unrelated to this technique. Vents in the left heart are not required under most circumstances.

Adult↗
PubMed1975

Late complications of aortic valve replacement with cloth-covered, composite-seat prostheses. A six-year appraisal.

Advanced actuarial techniques are used to analyze early and late results in a closely followed series of 396 patients who received a cloth-covered, composite-seat aortic prosthesis. Late mortality and various complications are carefully assessed, and most late deaths are seen to be unrelated to the prosthesis. One hundred sixteen patients with Model 2310-2320 prostheses who received warfarin postoperatively had no thromboembolic complications in 360 patient-years of follow-up (average, 3.1 years per patient); 134 patients who had the same prosthesis but did not receive warfarin had 9 emboli per 100 patient-years (average follow-up, 1.7 years per patient; total, 228 patient-years). By comparison, in 9 years' experience with non-cloth-covered Model 1200-1260 valves, 132 patients had 4.0 emboli per 100 patient-years (average follow-up, 5.1 years; total, 673 patient-years). The safety of cloth-covered valves is clearly enhanced by concomitant use of anticoagulants; the possibility that antiplatelet drugs may suffice has not yet been demonstrated. Strut cloth wear was found at reoperation in 10 patients. The Model 2400 composite strut ("track") valve with a narrow metal track on the inner surface of each strut prevents this complication.

Adolescent↗
PubMed1975

An improved statistical method for assessing the results of operation.

The advantages of the acturarial method of analyzing postoperative survival are now widely accepted. In evaluating the late results of heart valve replacement operations, however, certain nonfatal complications must also be considered. The use of individual event-free rates does not portray individual risk, since some valves have multiple complications. By using cummulative complication-free rates, however, it is possible to estimate the percentage of valves active and free from certain major complications for each postoperative interval. A series of actuarial curves is used, each of which represents a different major complication. These curves are subtracted progressively from the total of valves at risk, and an acturial representation of complication-free survival results.

Heart Valve Prosthesis↗
PubMed1975

Antireflux ureteroileal anastomoses in humans.

It is now apparent that the standard total cystectomy and Bricker procedure, by eliminating the ureterovesical junction with its reliable antireflux mechanism, markedly reduces the protection of the upper urinary tracts. In an attempt to restore this protective principle, the subserosal ileoureteral antireflux procedure was devised and subsequently performed in 6 patients with infiltrating bladder carcinoma. The operation is technically easy to perform, it is not time consuming and has consistently prevented ileoureteral relux without causing obstruction. There have been no serious complications, no episodes of pyelonephritis or urinary leakage and no evidence of renal functional deterioration as measured by serum creatinine and IVP. Although it is still to early to predict the eventual long-term results our experience with the first 6 patients with the antireflux ileoureteral anastomosis suggests that this modification of the original Bricker procedure offers superior protection to the upper urinary tracts.

Carcinoma, Squamous Cell↗
PubMed1975

Acute coronary insufficiency. An urgent surgical condition.

In 41 of 220 consecutive patients who had a coronary artery bypass operation between July 1973 and March 1974 the operation was for acute coronary insufficiency (recurrent chest pain with transient electrocardiographic changes persisting after admission to hospital). Their mean age was 54 (range 33-70 years). Eleven patients had had angina before, 14 had had at least one myocardial infarction, and 16 presented de novo. Eight of the latter 16 patients required only a single graft, usually to the left anterior descending artery, a significantly greater number than the two of the other 25 patients (P less than 0.01). Fourteen of these 16 patients had normal ventricular contraction, a significantly higher proportion than the 13 of the remaining 25 (p less than 0.05). No collaterals were seen in any of the 10 with single-vessel disease, which was significantly fewer than five out of 18 with double- and nine out of 13 with triple-vessel disease (P less than 0.005). Patients with rapidly developing obstruction, especially in the proximal left anterior descending artery, may not have time to develop collaterals, present acutely with good ventricular function, and may be particularly at risk. There was no operative mortality. The patients had a perioperative myocardial infarction, and there was one late death. At follow-up averaging 9-7 months (range 5-14 months) 32 (80%) patients were angina-free, no myocardial infarctions had occurred, and 85% were fully employed. Urgent coronary artery bypass grafting is a safe and effective treatment for acute coronary insufficiency.

Adult↗
PubMed1975

Diastolic murmurs in the presence of Starr-Edwards mitral prosthesis.

Diastolic murmurs associated with the Starr-Edwards mitral prosthesis have not been described previously. In this report, five patients with mitral prostheses are described in whom apical mid-diastolic and presystolic murmurs resulted from two different causes. Three patients had clots obstructing the prosthetic orifice. The other two had normally functioning protheses and moderately severe aortic insufficiency. The occurrence of mid-diastolic and presystolic murmurs in the presence of a normally functioning prosthetic mitral valve demonstrates that 1) the mid-diastolic Austin Flint murmur can occur in the absence of incomplete mitral valve opening, premature mitral valve closure, vibrating mitral leaflets, or relative mitral stenosis and 2) the presystolic Austin Flint murmur can occur in the absence of incomplete valve opening or presystolic mitral regurgitation. However, the presystolic murmur was associated with early closure movement of the presthetic poppet.

Adult↗
PubMed1975

Surgical considerations in patients undergoing repeat median sternotomy.

A retrospective review of 122 repeat median sternotomy incisions in 100 consecutive patients was made to evaluate complications and management. Eighty-one patients had one repeat sternotomy, )6 had two repeat sternotomies, and 3 had three repeat sternotomies. All had valve procedures in the past and were reoperated upon for progressive rheumatic valvular disease or for complications related to the prostheses. Complications included operative hemorrhage in 8 patients, postoperative hemorrhage in 2, seroma in 4, and dehiscence, wound infection, and hematoma in 1 patient each. The most serious complication was hemorrhage and was the cause of the only operative death. Seven other patients survived hemorrhage encountered during repeat sternotomy. Control of massive hemorrhage during repeat sternotomy has been possible due to an organized approach to the patient with adhesions from previous surgery.

Adolescent↗
PubMed1975

Tricuspid atresia with christmas disease (hemophilia B). Report of a case.

A case combining Christmas disease and tricuspid atresia is presented. A severe coagulation defect in a hypoxic, polycythemic patient poses an added grave risk to major surgery. In the presence of marked and worsening symptoms, however, major surgery can be performed in these difficult cases. Close liason with a skilled hematology department is essential. Minimal tissue dissection is advised, and the usefulness of a reversed saphenous vein conduit is described.

Adolescent↗