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Biomedical subjects

G K Sethi

Publications and source records attributed to G K Sethi.

At least 73 records · Page 4Linked to original sources
PubMed1988

Inadequacy of the Gorlin formula for predicting prosthetic valve area.

A total of 135 patients with normally functioning prosthetic aortic valves who were catheterized 6 months after placement of Hancock, modified Hancock or Bjork-Shiley prostheses were studied to determine the magnitude of error in Gorlin formula estimates of prosthetic aortic valve area. All patients were male, selected from 13 participating hospitals and routinely followed after valve replacement for 5 years. Hemodynamically determined Gorlin valve areas were compared with independently verified actual valve areas. Actual Hancock areas were measured from videotapes of valves exercised in a pulse duplicator flow model. Actual Bjork-Shiley areas were calculated directly from the valves' inner ring radius. Gorlin valve areas correlated poorly with actual valve areas (r = 0.39). The mean Gorlin formula error was 0.36 cm2 (standard deviation = 0.32). Gorlin areas overestimated actual areas by greater than 0.25 cm2 in 43 patients (32%) and underestimated actual areas by greater than 0.25 cm2 in 29 (21%). It was concluded that the Gorlin formula inaccurately predicts prosthetic valve area in the aortic position. Overreliance on this formula in assessing aortic stenosis could lead to errant clinical decisions.

Aortic Valve↗
PubMed1988

Six month postoperative hemodynamics of the Hancock heterograft and the Björk-Shiley prosthesis: results of a Veterans Administration cooperative prospective randomized trial.

In a Veterans Administration Cooperative Study involving 13 medical centers, 575 patients undergoing single valve replacement were prospectively randomized to receive either the standard Björk-Shiley prosthesis or the Hancock porcine heterograft (with a modified orifice for sizes 23 and smaller). The hemodynamic data in the 268 patients who underwent cardiac catheterization an average of 6 months (range 3 to 12) postoperatively are reported. Statistical analyses were performed on valve sizes 23, 25 and 27 in the aortic position, and 29, 31 and 33 in the mitral position. A wide variation was observed in mean pressure gradient and calculated orifice area in both valve types within all sizes in both the aortic and the mitral positions. In the aortic position, the Björk-Shiley prosthesis tended to have a lower pressure gradient and larger calculated orifice area than the Hancock heterograft, but the differences in gradient between the two valve types were significant only in the larger-sized valves. The difference in calculated area between the two valve types was not significant within each valve size. In the mitral position, there were no differences in gradient and calculated orifice area between the two types of prostheses. The postoperative cardiac index, regurgitant volume, pulmonary artery systolic and mean pressures, left ventricular end-diastolic pressure, left ventricular ejection fraction and left ventricular end-diastolic volume index did not differ in patients receiving the Björk-Shiley prosthesis from values in patients receiving the Hancock heterograft. Hence, the overall hemodynamic performance of both types of valves is remarkably similar. The choice between these two prostheses should, therefore, be governed not by the hemodynamic performance, but by other factors such as valve durability, risk of anticoagulation and incidence of valve-related complications.

Aortic Valve↗
PubMed1987

Comparison of outcome after valve replacement with a bioprosthesis versus a mechanical prosthesis: initial 5 year results of a randomized trial.

The Veterans Administration Cooperative Study on Valvular Heart Disease was organized to compare survival and incidence of valve-related complications between patients receiving a bioprosthesis (the Hancock porcine heterograft) and a mechanical prosthesis (the Björk-Shiley spherical disc valve). Five hundred seventy-five patients undergoing single aortic or mitral valve replacement were randomized at surgery to one of the two valve types. At an average follow-up of 5 years (range 3 to 8) there are no statistically significant differences in survival between patients with the two valve types in the aortic valve replacement group. There is a statistically nonsignificant trend toward improved survival in patients undergoing mitral valve replacement with a bioprosthesis compared with a mechanical prosthesis (5 year survival probability was 0.70 +/- 0.05 and 0.58 +/- 0.06, respectively). Fatal and nonfatal valve-related complications occurred significantly less frequently in patients with a bioprosthesis compared with a mechanical prosthesis for both mitral and aortic valve replacement. Five year complication-free probability was 0.67 +/- 0.05 and 0.45 +/- 0.06, respectively, for patients with mitral valve replacement and 0.63 +/- 0.04 and 0.53 +/- 0.04, respectively, for those with aortic valve replacement. The difference in overall complication rates was largely due to the increased number of clinically significant but nonfatal bleeding episodes in patients receiving a mechanical prosthesis. Adjustment for differences in baseline characteristics between patients receiving a mitral mechanical prosthesis and a mitral bioprosthesis reduced the statistical significance of the difference in both mortality and complications.

Aortic Valve↗
PubMed1987

Clinical, hemodynamic, and angiographic predictors of operative mortality in patients undergoing single valve replacement. Veterans Administration Cooperative Study on Valvular Heart Disease.

Preoperative characteristics of 964 patients in the Veterans Administration Cooperative Study on Valvular Heart Disease undergoing single valve replacement were examined to determine predictors of operative mortality. The operative mortality rate was 8.3% in 661 patients having isolated aortic valve disease and 7.5% in 239 patients having isolated mitral valve disease, but 12.5% in 64 patients with multivalve disease undergoing single valve replacement. For the aortic valve replacement subgroup, three-vessel coronary artery disease, left ventricular systolic pressure, prior cardiac operation, body surface area, and cardiac index were related to operative mortality. In the mitral valve replacement group, there was a strong association of operative mortality with advanced age, exertional dizziness, reduced cardiac index, left ventricular contraction grade, ST segment depression on the resting electrocardiogram, and pleural effusion. The risk of operative death for an individual patient undergoing aortic or mitral valve replacement may be estimated with the use of independent risk factors.

Adult↗
PubMed1986

Intravenous infusion of prostaglandin E1 (PGE1) in management of limb ischemia.

Twenty-three patients who had advanced arteriosclerotic disease of the lower extremities as manifested by rest pain, nonhealing ischemic ulcers, or impending gangrene and who were not candidates for direct arterial revascularization procedure underwent intravenous infusion of prostaglandin E1 (PGE1). Thirty-nine per cent of the patients showed subjective and/or objective improvement in the blood supply, and in 22 per cent (5 patients) amputation was avoided. Complications were minor and disappeared once the infusion was discontinued. PGE1 in prescribed dosages can be safely infused intravenously. Even though the results are not as encouraging as when PGE1 is given by the intra-arterial route, IV therapy improves the ischemic symptoms and avoids the necessity of amputation in some patients.

Adult↗
PubMed1982

Dimensional characteristics of left ventricular function after coronary artery bypass grafting.

During coronary artery bypass grafting, 20 patients underwent epicardial placement of miniature ultrasonic dimension transducers across the minor-axis diameter of the left ventricle to monitor cardiac function postoperatively. Left atrial or left ventricular pressure was measured in all patients, and thermodilution cardiac outputs were obtained routinely. Data from 1, 6, 12 and 20 hours postoperatively were analyzed. Directional changes in systolic shortening of the left ventricular diameter correlated well with stroke volume measured by thermodilution techniques and could be used as an on-line index of cardiac output. In five patients who had preoperative abnormalities in wall motion, systolic bulging of the minor-axis diameter was seen initially after revascularization and then gradually resolved over the next 12 hours. Systolic bulging that did not resolve was the earliest indication of a perioperative myocardial infarction in another patient. The end-diastolic diameter increased progressively in all patients in the first 12 hours postoperatively and was associated with stabilization of cardiac function. This improvement in diastolic left ventricular filling was not reflected (p greater than 0.2) by changes in mean left atrial pressure. Therefore, ultrasonic assessment of left ventricular diameter is a simple, precise and safe method of monitoring systolic and diastolic ventricular function postoperatively.

Adult↗
PubMed1980

Acquired left ventricular-right atrial fistula following aortic valve replacement.

Intracardiac communications produced as a complication of valve replacement can result in left-to-right shunts and a poor surgical result. The successful surgical closure of a left ventricular-right atrial fistula following aortic valve replacement is discussed. The intricate relationships of the membranous interventricular septum, the aortic, mitral, and tricuspid valves, and the aortic root predispose to the creation of abnormal intracardiac shunts when aggressive debridement of extensive valvular calcification is performed at the time of valve excision and replacement.

Aged↗
PubMed1980

Pulmonary hemorrhage associated with balloon flotation catheters: report of a case and review of the literature.

The development of the flow-directed balloon catheter has greatly facilitated the monitoring of seriously ill patients. As the use of this catheter has increased, so have the reports of complications, the most serious of which is fatal pulmonary hemorrhage. Eleven cases of pulmonary hemorrhage have been described in the literature, and we have reported an additional case. The presenting symptom in 10 patients was hemoptysis, and the course of eight of these patients was rapidly fatal. The most frequent significant finding at autopsy was a laceration of a small peripheral pulmonary artery, usually at a bifurcation. The pathogenesis, prophylaxis, and management of this complication are discussed.

Cardiac Catheterization↗
PubMed1979

Iatrogenic coronary artery stenosis following aortic valve replacement.

Until recnetly, coronary arterial perfusion was one of the best methods to protect myocardium during aortic valve replacement. However, the insertion of perfusion cannulas may produce immediate traumatic lesions and late stenosis of the coronary arteries, with grave consequences. Two patients with normal coronary arteries prior to operation developed obstruction of the maximal left main coronary artery following aortic replacement. One of these patients represents the first case of iatrogenic coronary arterial stenosis in which the aortic valve was replaced with a porcine bioprosthesis. Accelerating angina pectoris and ventricular arrhythmias were the presenting clinical manifestations. Aorta-coronary bypass grafting to the left anterior descending and circumflex coronary arteries was successfully performed in one patient, while the other patient died before investigative procedures could be undertaken. Any patient whose aortic valve has been replaced and who develops angina pectoris a few months after operation should be suspected of having developed stenosis of the proximal coronary artery. Coronary angiography should be perfomed promptly. Once the lesion is recognized, the operaiton should be performed posthaste because these lesions are life threatening owing to their proximal location and rapid evolution.

Aortic Valve↗
PubMed1978

Esophagopleural fistula following pulmonary resection.

The development of esophagopleural fistula following pulmonary resection is an uncommon but serious complication. The fistula may appear either soon after operation, due to direct trauma to the esophagus or to its blood supply during extensive dissection, or later, in association with the development of a bronchopleural fistula and empyema following the pulmonary resection. Treatment of these fistulas is usually complicated, and the recovery period is prolonged. Control of infection, hyperalimentation, obliteration of the empyema space, and closure of the fistula with a muscle or pleural flap are recommended methods of management. The pathogenesis, treatment, results, and prevention of this complication are discussed.

Adult↗
PubMed1978

Insidious strut fractures in a DeBakey-Surgitool aortic valve prosthesis.

Recent reports of cage wear occurring in DeBakey-Surgitool aortic valve prostheses prompted us to examine with image intensification all our patients who have had this type of prosthesis implanted. One patient, who was asymptomatic, was discovered to have a prosthesis with two fractured struts. This patient's prosthetic valve was replaced successfully with a stented porcine heterograft prosthesis. Including the valve removed from this patient, 8 DeBakey-Surgitool aortic valves with structural defects have been reported to the manufacturer. In the absence of a catastrophic event, patients with valves having fractured or worn struts may be totally asymptomatic, and routine periodic roentgenographic examination may be the only way of detecting strut wear or fracture.

Adolescent↗
PubMed1977

The value of multiple-plane angiography in the assessment of aortoiliac disease.

Aortography, regarded as a definite diagnostic study in evaluating pateints with peripheral vascular occlusive disease, is usually done in the anteroposterior projection only. Occasionally, a significantly diseased area may not be identified on this projection, and an oblique view of the aortoiliac region may clarify the presence and severity of arteriosclerosis. At present, our indications for obtaining oblique views of the aortoiliac region are (1) when symptoms correlate poorly with the arteriographic findings in the anteroposterior projection, or (2) when the severity of the lesion is in doubt. These projections also are used to evaluate patients who have had previous aortoiliac bypass grafts and in whom ischemic symptoms recur. Patients with unilateral limb ischemia who are being considered for femorofemoral bypass graft procedures or iliac endarterectomy are also appropriate candidates, especially when radiopaque material overlies the vessels. Arteriograms in oblique projections also are recommended for more precise evaluation of the origin of the profunda femoris artery.

Angiography↗
PubMed1976

Incarcerated diaphragmatic hernia: report of an unusual case.

Traumatic diaphragmatic hernias, although quite common are frequently overlooked as a cause of intestinal obstruction. The hernia may produce significant symptoms acutely or manifest itself many years following the initial injury. A high index of suspicion is necessary to diagnose intestinal obstruction due to incarcerated diaphragmatic hernia. The operation should be performed through the transabdominal approach when hernia occurs acutely, and the transthoracic approach is recommended when herniorrhaphy is performed long after the time of injury. A case of incarcerated traumatic diaphragmatic hernia that occurred 19 years following a gunshot wound of the chest is reported. The intestinal obstruction was initially thought to be due to cancer of the splenic flexure of the colon.

Colonic Diseases↗
PubMed1976

Experience with the DeBakey-surgitool aortic prosthetic valve.

The DeBakey-Surgitool aortic valve differs from popular cloth-covered prostheses by having a bare metal cage and a pyrolytic carbon ball. This valve was implanted in 37 patients. There were 7 operative deaths (19%), none of which was related to the valve design. Thirty survivors have been followed up to five years with 12 late deaths. The single thromboembolic event resulted in the only valve-related death. One patient developed a periprosthetic leak and another has hemolytic anemia. The incidence of thromboembolism in small series (3%) is comparable to that with the cloth-covered valves. This and the absence of complications related to cloth wear are important considerations when selecting a prosthesis.

Adult↗
PubMed1976

The sutureless aortic valve prosthesis: experience with and technical considerations for replacement of the early model.

Reoperation was performed in seven (16%) of 43 patients with early models of Magovern sutureless aortic valve prostheses, because of thromboembolism and ball variance. All patients survived reoperation with no major complications. Removal of the sutureless prosthesis was not difficult when an insertion tool of proper size was used. A scarred annulus remained which was favorable for the suturing of a new prosthesis. The incidence of disabling thromboembolism (42%) and poppet failure (21%) is high with these early models. When these complications occur, replacement of the prosthesis is recommended to prevent death or recurrent embolic episodes.

Adult↗