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Biomedical subjects

J F Howell

Publications and source records attributed to J F Howell.

At least 19 recordsLinked to original sources
PubMed1989

The St. Jude valve prosthesis: analysis of the clinical results in 815 implants and the need for systemic anticoagulation.

Between July 1979 and December 1984, 785 patients received 815 St. Jude Medical valve prostheses. Valve-related mortality in the follow-up period was due to thromboembolism in seven cases, anticoagulant-related hemorrhage in three and perivalvular leak in two. Freedom from valve-related death or reoperation at 3 years was 96.4% for aortic valve replacement and 98.3% for mitral valve replacement. The overall rate of thromboembolism was 2.6%/patient-year with warfarin, 9.2%/patient-year with antiplatelet medication and 15.6%/patient-year in patients with no anticoagulant therapy. One episode of thrombotic obstruction of a mitral valve, in a patient receiving no anticoagulant therapy, resulted in an occurrence rate of such obstruction of 0.22%/patient-year. Valve replacement with the St. Jude valve produced excellent clinical results, but long-term anticoagulation with warfarin was required to minimize thromboembolic complications. The use of antiplatelet agents alone provided inadequate protection.

Adolescent↗
PubMed1988

Operative and long-term results of staged contralateral carotid endarterectomy: a personal series.

The operative risks as well as the proper interval for patients undergoing staged contralateral carotid endarterectomies remain uncertain. The long-term incidence of stroke after bilateral carotid endarterectomy is also poorly documented. In this report the results of staged contralateral carotid endarterectomies performed by one surgeon in a consecutive series of 89 patients are analyzed. No deaths occurred after a first or contralateral carotid endarterectomy. Four (4%) neurologic deficits (three minor and one major) occurred after a first operation, whereas only one (1%) major neurologic deficit occurred after a contralateral carotid endarterectomy. Postendarterectomy hypertension was noted in 33 (37%) patients after a first operation, and in 62 (70%) patients after a contralateral carotid endarterectomy (p less than 0.00001). No correlation existed among the intervals between carotid operations and the incidence or duration of hypertension after a contralateral carotid endarterectomy. From our results we conclude that the staged contralateral carotid endarterectomy can be safely performed with a stroke-mortality rate approaching 1%. Postendarterectomy hypertension, although more frequent after the contralateral operation as compared with the first operation, has no correlation with the interval between procedures. After a staged bilateral carotid endarterectomy, only one (1%) patient experienced transient ischemic attack symptoms, but five (6%) patients suffered late stroke (four fatal).

Adult↗
PubMed1979

Results of epicardial pacing by the left subcostal approach.

We have determined the clinical course of 200 consecutive patients (mean age, 67.5 years) in whom epicardial pacing was established by the left subcostal route by insertion of 2 sutureless myocardial electrodes and a demand bipolar generator. There was 1 intraoperative death (0.5%). The overall 30-day perioperative mortality was 4 of 200 patients (2.0%). The principal postoperative complications included postpericardiotomy syndrome in 8 patients (4.0%), pneumonia or marked atelectasis in 2 patients (1.0%), and pulmonary embolus in 1 patient. Hemiplegia developed in 2 patients at 9 and 10 days, respectively, after operation, and transient monoparesis developed in another patient (1.5%). There were no wound infections, but the one wound dehiscence required resuturing. Follow-up has been completed in all patients from 1 to 39 months postoperatively (mean, 14.9 months). There have been 21 late deaths. Late lead thresholds were recorded for 45 individual leads from 26 patients up to 35 months after operation. The results obtained indicate that for patients undergoing primary implantation, the sutureless myocardial electrode provides reliable lead function. However, patients who required reoperation because of previous pacemaker failure due to threshold rise have done poorly as a group and may be better managed with lithium high-output pacemaker generators.

Adolescent↗
PubMed1979

Improved results of operation for ruptured abdominal aortic aneurysms.

Of 1,393 consecutive patients operated on for aneurysm of the abdominal aorta between 1964 and 1978, 61 consecutive patients had undergone emergency operation for ruptured abdominal aortic aneurysm, for an incidence of 4.4% (61 of 1,393). There were 57 men and four women; their mean age was 77.5 years, with a range of 49 to 93 years. In 21 patients the diagnosis of aneurysm had been known from 1 day to 5 years prior to rupture. Hypotension (less than 100 mm Hg systolic) was present in 27.9% of patients (17 of 61) on admission to hospital and prior to operation in a total of 44.3% patients (27 of 61). Operation was begun in eight patients with an initially unrecordable blood pressure. The perioperative mortality rate (30 day) was 14.8% (nine of 61). The two factors most influencing survival were age [no patient younger than 60 years died vs. 40% of patients (four of 10) older than 80 years] and the magnitude of blood loss (survivors lost a total of 4,513 ml vs. 8,500 ml in those who died). Thus the most common cause of death was myocardial infarction (six of eight) in elderly patients, secondary to poorly tolerated severe hypovolemia. The results of this study suggest the need for avoidance of technical problems during operations, earlier referral of patients with known abdominal aortic aneurysms, especially the elderly, and early diagnosis with immediate operation for ruptured aneurysms.

Aged↗
PubMed1978

Fortuitous rupture of aortic aneurysm: a catastrophic event affording time for surgical cure.

The rupture of an aortic aneurysm is generally a fatal event, but occasionally the rupture will occur into an adjacent vascular structure, thereby preventing exsanguination and affording temporary survival. Three cases are presented illustrating the fortuitous nature of the rupture of an aortic aneurysm into a vascular structure. The first patient had an atherosclerotic abdominal aortic aneurysm that ruptured into the inferior vena cava and was successfully repaired. The second case demonstrates the formation of a fistula from the aorta to the left pulmonary artery in a patient with a syphilitic thoracic aortic aneurysm. In the third patient a dissecting aneurysm of the aortic root that communicated with the right ventricle after coronary bypass surgery was successfully repaired. Rarely, aortic aneurysms will rupture fortuitously into vascular capacitance structures. These three cases emphasize the need for early accurate diagnosis and the institution of appropriate surgical measures.

Aged↗
PubMed1978

Operative risk in patients with previous coronary artery bypass.

Noncoronary operations were performed in 358 patients who had undergone a previous coronary artery bypass grafting, with a mortality of 1.1%. In 70 patients (20%), the staged operation was planned and subsequent operation performed 6 to 12 weeks after bypass with no cardiac complications and 1 death. In the others, operation was performed 10 days to 89 months after bypass for either urgent reasons or new lesions. Three deaths and significant numbers of medical cardiac complications occurred in those patients subjected to operation within 30 days. The subsequent operation was vascular in 232 patients, with 3 deaths (1.3%); thoracic in 43, with no deaths; and general surgical in 113, with 1 death (0.9%). Follow-up study showed 307 patients (87%) still alive after 30 days to seven years. Late death was due to myocardial infarction in only 12 patients (3%). This study suggests that the risk of operation is as good in patients who have had successful coronary artery bypass as in those without coronary artery disease, and that the risk of subsequent myocardial infarction is small.

Coronary Artery Bypass↗
PubMed1976

Aneurysm of the main pulmonary artery: long-term survival after aneurysmorrhaphy and closure of a ventricular septal defect.

Pulmonary artery aneurysm (PAA) usually carries an ominous prognosis due to the associated pulmonary hypertension. Six years ago a patient with a PAA secondary to cystic medial necrosis and pulmonary hypertension due to a ventricular septal defect (VSD) was treated by aneurysmorrhaphy and closure of the VSD. Although the patient had early postoperative cardiac failure, his cardiopulmonary status stabilized, and he has done well without recurrence of his aneurysm or cardiac failure. This report summarizes the patient's clinical course, operative treatment, and long-term follow-up.

Adult↗
PubMed1976

Left subcostal insertion of the sutureless myocardial electrode.

This report describes the use of a left subcostal extrapleural supradiaphragmatic approach to the heart for myocardial sutureless electrode insertion. Electrode insertion by this approach has consistently produced low electrode thresholds, and the ability to insert electrodes into the left ventricle or septal area of the right ventricle is considered an advantage. This technique has now been used in 52 patients. Postoperative morbidity and complications have been minimal. The procedure appears to be well tolerated in the elderly, poor-risk patient and has been a useful technique for revision of failed pacemaker systems. We believe this procedure reduces the indications for permanent transvenous pacing.

Adult↗
PubMed1976

Aneurysm of the sinus of Valsalva producing obstruction of the left main coronary artery.

An aneurysm of the left sinus of Valsalva compressed the left main coronary artery and the patient experienced anginal pain. Surgical correction consisted of obliteration of the orifice of the aneurysm, aortic valve replacement, and a saphenous vein bypass from the ascending aorta to the distal left anterior descending coronary artery. Postoperative studies revealed excellent function of the prosthetic valve, no recurrence of the aneurysm and retrograde filling of the left anterior descending and circumflex coronary arteries. Three years after the operation, the patient is asymptomatic.

Angiocardiography↗
PubMed1975

Successful partial excision of an intramural fibroma of the left ventricle.

A report of the only surviving adult to undergo partial excision of an intramural cardiac left ventricular fibroma is presented. Good results were obtained by relieving outflow tract obstruction through partial excision of the tumor from the septum and left ventricle. The need for conservative surgical treatment of patients with this rare, benign tumor is emphasized.

Adolescent↗