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Biomedical subjects

K V Hall

Publications and source records attributed to K V Hall.

At least 37 records · Page 2Linked to original sources
PubMed1985

Seven and one-half years' experience with the Medtronic-Hall valve.

The Medtronic-Hall valve was developed to improve on existing tilting disc valves by reducing the risk of valvular thrombosis. This was to be accomplished by improving the hemodynamics and by allowing the disc to move downstream away from the orifice during opening. The valve was also designed for maximal structural durability to minimize the risk of mechanical breakage. With more than 1,000 Medtronic-Hall valves implanted since 1977, the clinical results have been very encouraging. The rates of thromboembolism and thrombosis are low, there have been no mechanical failures and the hemodynamic function, especially with the smaller valves, is excellent.

Equipment Failure↗
PubMed1985

Muscle transposition for treatment of osteomyelitis of the tibia.

A series of 24 consecutive patients with osteomyelitis of the tibia and soft tissue defects were treated according to the principle of radical excision of the infected bone together with transposition of muscle flaps and primary skin cover as a one-stage procedure. External fixation was used for stabilization of bone. The mean duration of osteomyelitis before radical operation was 72 weeks and the previous stay in hospital averaged 15 weeks. Twenty-one patients had previously undergone 3.7 operations because of the infection. Staphylococcus aureus was cultured in 50% of the patients, while no bacteria could be identified in six patients. Appropriate antibiotics were given for an average of eight weeks. In four patients a secondary bone transplant and in three patients another skin transplant was necessary. One patient refusing further reconstructive surgery insisted on an above-knee amputation because of persisting infection. After an average observation time of 2 1/2 years no infection or instability of the tibia could be demonstrated, but one patient showed two small skin defects. These results indicate that radical excision of infected bone in combination with muscle transposition and primary skin cover is effective in the treatment of posttraumatic osteomyelitis of the tibia.

Adolescent↗
PubMed1985

Bilateral orbital floor fractures.

Nineteen patients operated on suspicion of bilateral orbital floor fractures are described. All of the patients had severe comminute midfacial fractures. Orbital floor deficiency requiring transplantation was found in 68% of the cases, demonstrating homolateral maxillary and zygomatic fractures. On the basis of their findings, the authors recommend acute reposition of the fractures and routine exploration of the orbital floor in the case of deficiencies requiring transplantation and in cases of homolateral combined maxillary and zygomatic fractures.

Adolescent↗
PubMed1985

Unilateral orbital floor fractures.

Ninety patients operated on, on suspicion of unilateral orbital floor fractures are described. Age, sex, and etiology are given. Operative indication is examined and related to the operative findings. Fifty-six of the patients had fractures requiring transplantation, 24 had fractures which did not. Ten patients had no fractures. Only autogenous bone graft was used. The patients were examined three months and one to 11 years postoperatively (questionnaire). Of 82 operated patients who answered the questionnaire diplopia was found in eight, enophthalmos in two, hypesthesia in 18, reduced mobility in four and sinuitis in four. Preoperative X-ray: Three patients showed false positive X-ray findings. In 19 patients with false negative X-ray findings 12 required transplantation. Twenty-five tomographed patients showed fractures, two of which proved to be false positives. In eight patients with negative tomographical findings, fractures were found, seven of which required transplantation. The frequency of complications assessed in relation to the time of operation shows no significant difference, if surgery takes place within seven days of injury. Surgery performed later than this seems to produce more cases of chronic sinuitis.

Adolescent↗
PubMed1984

The burn situation in Gizan. Planning and implementation of a Burns Unit at the King Fahd Central Hospital, Gizan, the Kingdom of Saudi-Arabia.

A 500-bed referral hospital was designed in 1975 in the health region of Gizan , the Kingdom of Saudi-Arabia. According to an agreement of 1981 between the Danish Ministry of the Interior and the Ministry of Health for the Kingdom of Saudi-Arabia, Danish cooperation to start and run this hospital was initiated. At the end of 1982 an investigation was made as to whether there was a need for a Burns Ward, a Burns Unit or a Burns Center. The epidemiology (number, severity and causes of burns) in the Gizan region (500 000 inhabitants) was investigated and all in-patients were examined, after which a recommendation to establish a Burns Unit was made. The Danish personnel arrived in April 1983, and the first patient was admitted to the Unit in May 1983. During the first 5-month period 46 patients with burns and 77 other patients requiring plastic surgery were treated. It seems therefore that the need for a Unit for Burns and Plastic Surgery has been proved. The number of inhabitants in the Gizan health region corresponds to that of the municipality of Copenhagen (500 000), and in the future the epidemiology, treatment and results of treatment will be compared in these two areas.

Adolescent↗
PubMed1983

A 5-year follow-up of the Medtronic-Hall valve: survival and thromboembolism.

Throughout the period 1977 to 1982, 436 patients underwent aortic valve replacement (AVR), 106 underwent mitral valve replacement (MVR) and 56 patients underwent double valve replacement (DVR), with the Medtronic-Hall prosthetic valve (previous equivalent: Hall-Kaster valve). Early and late mortality were 4% and 9% for AVR, 8% and 11% for the MVR and 7% and 13% in the DVR, respectively. Actuarial survival after 5 years of follow-up was 80.9% for AVR, 75.4% for MVR and 81.0% for the DVR. Thromboembolic complications included 2 cases of valve thrombosis in the AVR, in one case secondary to valve endocarditis. Eleven further thromboembolic episodes occurred in 10 patients with AVR. In MVR an aspergillus thrombus was found on the valve at autopsy in a patient dying from multiple cerebral aspergillus abscesses. Five further thromboembolic episodes occurred in 4 patients with MVR. In the DVR group there was one valve thrombosis and one further patient with a thromboembolic episode. The actuarial probability of remaining free from thromboembolism at the end of the 5 years of follow-up was 92.5% for AVR and 83.7% for MVR.

Aortic Valve↗
PubMed1983

A 5 year experience with the Medtronic-Hall disc valve prosthesis.

Throughout the period from 1977 to 1982, 426 patients underwent aortic valve replacement, 106 patients underwent mitral valve replacement, and 56 patients had double valve replacement with the Medtronic-Hall (previous Hall-Kaster) valve. Early and late mortality was 4% and 9% in the aortic group, 8% and 11% in the mitral group, and 7% and 13% in the double valve group. There was an 81% probability of surviving 5 years after aortic or double valve replacement, and a 75% probability of surviving 5 years after mitral valve replacement. Postoperative follow-up studies revealed low pressure gradients across the aortic as well as across the mitral valve prosthesis, irrespective of valve size. Exercise studies indicated good tolerance of increasing cardiac output during strenuous exercise tests in patients with aortic valve prosthesis. Thromboembolic complications in the aortic series included two cases of valve thrombosis and 11 thromboembolic episodes in 10 patients. In the mitral series an aspergillus thrombus was found on the valve at autopsy in a patient dying from multiple cerebral aspergillus abscesses, and five thromboembolic episodes occurred in four additional patients in the mitral series. In the double valve series there was one valve thrombosis and one patient had a thromboembolic episode.

Actuarial Analysis↗
PubMed1980

Arterial occlusive disease of the upper extremity.

Twenty-five upper extremities were operated upon in 24 patients because of arterial occlusive disease. Transthoracic endarterectomy was performed in 4 patients with short central occlusions of the subclavian artery. In the remaining patients, various bypass procedures were performed using reversed autogenous veins or prosthetic grafts. There were 2 early and 6 late deaths. One prosthetic graft had to be removed 2 months after the operation because of infection. At follow-up, 9 months to 17 years after surgery, 11 bypass grafts were patent. One vein graft and one prosthetic graft had occluded. The surgical technique, types of graft to be used, and the relation to long-term patency are briefly discussed.

Adolescent↗
PubMed1979

Clinical and hemodynamic results after combined aortic and mitral valve replacement with the Lillehei-Kaster pivoting disc valve.

Combined mitral and aortic valve replacement with the Lillehei-Kaster pivoting disc valve prosthesis was performed in 23 patients. Hospital mortality rate was 8.3 per cent. Detailed postoperative clinical and hemodynamic studies were performed after a mean follow-up period of 24.4 months. Replacement of both valves had resulted in a marked symptomatic and hemodynamic improvement with a normal or nearly normal resting value of cardiac output, pulmonary arterial pressure, and pulmonary vascular resistance while left ventricular end-diastolic pressure (LVEDP) had increased significantly. The rise in left ventricular end-diastolic pressure most probably might be related to the simultaneous rise in cardiac output (Starling mechanism), reflecting the severity and irreversibility of the underlying myocardial disease. Most patients also had systolic gradient across the aortic prosthesis, as well as diastolic gradient across the mitral prosthesis. The gradients across the mitral prosthesis were approximately the same as seen after single valve replacement, while the pressure gradients across the aortic prosthesis were somewhat smaller than previously reported. Angiographic studies of the aortic valve movement indicated that the opening angle of the disc was approximately 60 degrees, and thus less than according to the valve specifications.

Adult↗
PubMed1979

Primary results with the new Hall-Kaster disc valve prosthesis in mitral position.

The Hall-Kaster central flow prosthetic heart valve was introduced in 1977 in an attempt to improve the hemodynamics of the disc valve prostheses. Towards this accomplishment, innovations in the tilting axis, the disc guidance mechanisms, and disc translational freedom cooperate to improve flow through both orifice segments of the open valve. The present study reports on the primary clinical and hemodynamic findings in the first 20 patients (mean age 57.6 years) with isolated mitral valvular disease, examined 3--4 months after insertion of the Hall-Kaster disc valve prosthesis. The hemodynamic findings displayed low gradients and high calculated valve areas (5). At rest, the mean diastolic pressure gradient across the smallest prosthesis used (O.D. 27) averaged 3.0 mmHg, vs. 2.6 mmHg across the largest valve sizes (O.D. 29--31). Calculated valve area was on an average 3.08 cm2 for the smaller valve, and 3.47 cm2 for the larger valves, which corresponded to an utilization of 81% and 77% of the orifice area measured in vitro. A comparison with earlier studies of mean diastolic mitral gradients with different mitral prostheses indicates that the Hall-Kaster disc valve represents an improvement towards a hemodynamically more efficient prosthesis for mitral valve replacement.

Aged↗
PubMed1979

Intraoperative and postoperative hemodynamic studies in patients undergoing aortic valve replacement with the Hall-Kaster cardiac disc valve prosthesis.

Intraoperative and postoperative hemodynamic measurements in the first patients to receive the Hall-Kaster cardiac disc valve prosthesis in the aortic position demonstrated the principal hemodynamic pattern of this new mechanical valve. These hemodynamic studies demonstrated favourable transvalvular gradient values and a degree of flow area utilization of the valve orifice which was close to its theoretical maximum. The Hall-Kaster prosthesis thus presented improved flow characteristics in patients undergoing aortic valve replacement, which is considered of particular importance to the patients with a narrow aortic root.

Adult↗
PubMed1979

Primary clinical experience with the Hall-Kaster valve in the aortic position: results at 3 months including hemodynamic studies.

The Hall-Kaster pivotal disc prosthetic heart valve was introduced in 1977. The primary goal of the design was to obtain the least possible obstruction to flow. Toward this end, innovations in the tilting axis, disc guidance mechanisms, and disc translational freedom combine to improve flow through both orifice segments of the open valve. The present study reports the primary clinical and hemodynamic findings in 28 patients (mean age, 53.8 years) with aortic valve disease, examined 3 months after insertion of the Hall-Kaster pivotal disc valve. The hemodynamics findings displayed low gradients and high calculated orifice areas. Satisfactory flow was observed through both the major and minor openings of the prosthesis. There were no arterial thromboembolic episodes. The increase in serum lactate dehydrogenase activity was moderate, indicating a slight-to-moderate intravascular haemolysis.

Adolescent↗
PubMed1979

Mitral insufficiency following myocardial infarction.

Severe mitral insufficiency following myocardial infarction in 15 patients is reported. The mean interval from infarction to surgery was 2.8 years. All patients were operated on with mitral valve replacement and in 14 aortocoronary bypass and/or resection of left ventricular aneurysm was necessary as well. Rupture of one or more heads of the papillary muscle was found in 5 patients. In another 5 the papillary muscles were discoloured, fibrosed and shortened, and in the last 5 patients the mitral incompetence was caused by a marked dilatation of the atrioventricular ring. Five patients (33%) died, 3 early and 2 late after surgery. All the patients who died had a markedly imparied left ventricular function pre-operatively with end-diastolic pressures from 15 to 26 mmHg.

Coronary Artery Bypass↗