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Biomedical subjects

D O Monson

Publications and source records attributed to D O Monson.

At least 19 recordsLinked to original sources
PubMed1994

Disruption of sutured pulmonary valve in Fontan operation.

Two patients who had undergone a Fontan operation presented late with considerable disruption of a sutured pulmonary valve. Both patients had increasing ascites, decreased exercise tolerance, atrial arrhythmias, high right atrial pressure, and a large ratio of pulmonary blood flow to systemic blood flow. At operation, the main pulmonary artery was closed either by suturing the anterior and posterior walls together immediately distal to the pulmonary valve or by reinforcing the resutured pulmonary valve with a polytetrafluoroethylene patch. Both patients had an uneventful postoperative course, with disappearance of the symptoms and return of sinus rhythm. Although it is tempting to simply suture the usually thickened pulmonary valve in the Fontan operation, approximation of the pulmonary artery walls or patch reinforcement is necessary to minimize disruption.

Adult↗
PubMed1994

Extended aortic valvuloplasty for recurrent valvular stenosis and regurgitation in children.

Recurrent significant aortic valvular stenosis or regurgitation, or both, after balloon or open valvotomy in pediatric patients often necessitates aortic valve replacement. In an attempt to preserve the aortic valve, we performed extended aortic valvuloplasty in 21 children with recurrent aortic valve stenosis or regurgitation from January 1989 to March 1993. Previous related procedures were one open aortic valvotomy or more (n = 15), balloon valvotomy (n = 4), balloon valvotomy after surgical valvotomy (n = 1), and repair of iatrogenic valve tear (n = 1). Mean age at the time of the extended aortic valvuloplasty was 6 +/- 3.4 years. Mean pressure gradient across the aortic valve was 56 +/- 12 torr. Regurgitation was moderate (grade 2 to 3) in nine and severe (grade 4) in 12 patients. Extended aortic valvuloplasty techniques consisted of thinning of valve leaflets (n = 15), augmentation of scarred and retracted leaflets with autologous pericardium (n = 11), resuspension of the augmented leaflet (n = 14), release of the rudimentary commissure from the aortic wall (n = 5), extension of the valvotomy incision into the aortic wall on both sides of the commissure (n = 20), patch repair of the sinus of Valsalva perforation (n = 1), reapproximation of tears (n = 5), and narrowing of the ventriculoaortic junction (n = 2). No operative deaths occurred. The postoperative mean pressure gradient, assessed by most recent Doppler echocardiography or cardiac catheterization at a follow-up of 18 +/- 6 months, was 19 +/- 6 torr (p < 0.01 versus the preoperative gradient). Aortic regurgitation was absent in 13, mild in 6, and moderate-to-severe, necessitating subsequent aortic valve replacement, in 2. This short-term experience indicates that extended aortic valvuloplasty is a safe and effective surgical approach that minimizes the need for aortic valve replacement in children with significant recurrent aortic valve stenosis or regurgitation.

Actuarial Analysis↗
PubMed1989

Inferior vena cava interruption with the Hunter-Sessions balloon: eighteen years' experience in 191 cases.

Over a period of 18 years, 191 consecutive patients had interruption of the inferior vena cava with the Hunter-Sessions balloon for complications of deep venous thrombosis and pulmonary embolism. Causes of deep venous thrombosis and pulmonary embolism included the postoperative state (33%), cancer (32%), and stroke (11%). There were 93 females and 98 males; ages ranged from 17 to 90 years (average, 57 years). Indications for placement of the Hunter-Sessions balloon were as follows: contraindication to anticoagulants (33%), anticoagulant complications (24%), pulmonary embolism despite anticoagulants (45%), and others including inferior vena cava thrombus (12%). Sixty-eight percent had clinical phlebitis and 36% had positive venography results. Pulmonary embolism had occurred in 165 patients (86%). It was diagnosed by ventilation-perfusion scanning (75%), angiography (23%), or on clinical grounds (2%) in patients with confirmed deep venous thrombosis. At the time of the procedure 52% were in significant cardiopulmonary distress, and 10% were intubated and on respirators. Transjugular placement was done in 188 patients, and transfemoral placement was performed in three. All All tolerated inferior vena cava interruption. Thirty patients (15%) died while in the hospital an average of 21 days after balloon placement, which was unrelated to the deaths. Follow-up was 45 months. Ninety-four patients are dead, 95 are alive, and the status of two patients is unknown. Twenty-nine of 64 patients (45%) who died after they left the hospital died of cancer. At last follow-up, 75% of patients had legs free of edema and 25% had need for elastic stockings. No malfunction or migration has occurred with the device. No patient had a pulmonary embolism while in the hospital after insertion of the Hunter-Sessions balloon, and no patient died of pulmonary embolism. Late minor pulmonary embolism occurred in three patients.

Adolescent↗
PubMed1986

The detection of atrial and ventricular septal defects with electrocardiographically synchronized magnetic resonance imaging.

To evaluate the detectability of cardiac septal defects by electrocardiographically synchronized (ECG-gated) magnetic resonance imaging (MRI), 48 subjects were imaged, including 18 normal and 30 abnormal subjects in whom 22 ventricular septal defects (VSDs) and nine atrial septal defects (ASDs) had been diagnosed angiographically. Two radiologists with ECG-gated cardiac MRI experience read the scans in a blinded fashion, and the results were evaluated by receiver operator characteristic curve analysis. The detectability of VSDs appeared greater than that of ASDs, although statistical significance at the .05 level was not achieved. The reported sensitivity and specificity of echocardiography in the detection of VSDs is comparable to MRI, whereas echocardiography probably is superior to MRI for detection of ASDs. Although MRI is potentially valuable in the diagnosis of various complex congenital cardiac defects, echocardiography is probably superior in the detection of VSDs and ASDs.

Adolescent↗
PubMed1983

Disruption of aortic arch branches due to nonpenetrating chest trauma.

From 1967 through 1979, six patients sustained non-penetrating chest trauma with disruption of the Innominate, carotid, and subclavian arteries. Diagnosis was established in each case by aortography. Two patients with subclavian artery injuries underwent exploration through lateral thoracotomies, and three patients underwent sternotomy for innominate artery disruptions. A cervical approach was used for a common carotid artery disruption. One patient had innominate and left common carotid artery disruption. Two patients with subclavian injuries had associated bronchial disruptions. Cardiopulmonary bypass was used in one patient and should be available in all cases. One patient died with multiple vessel and bronchial disruption. A variety of repairs were used, varying from simple oversewing of the subclavian artery to elaborate graft replacement of the innominate and left common carotid arteries.

Accidents, Traffic↗
PubMed1981

Coarctation of the aorta: four unusual instances.

Four unusual instances of coarctation of the aorta are presented. Three coarctations were located proximal to the left subclavian artery, and the other was in the normal location with a patent ductus arteriosus and an anomalous distal right subclavian artery. Unusual coarctations can be identified on physical examination on the basis of variations of blood pressure and pulses in the upper extremities. Unilateral rib notching may be noted on chest roentgenogram, and an aortogram can delineate its exact location. Four separate means of surgical repair are described.

Adolescent↗
PubMed1980

Simultaneous aortic and renal artery reconstruction.

From 1970 to 1978, 39 patients underwent simultaneous aortic and renal artery reconstruction. Of these, 37 had severe single or bilateral renal lesions in combination with an aortic aneurysm, or symptomatic or asymptomatic aortoiliac disease. Two patients had renal arteries that originated from an abdominal aortic aneurysm. Thirty-two patients were hypertensive, one had chronic renal failure, and three others had asymptomatic renal lesions that were bypassed prophylactically. Operations performed included aortic replacement plus: single renal graft; bilateral renal grafts; renal graft plus contralateral nephrectomy; and renal graft plus mesenteric revascularization. All early postoperative deaths (four) occurred in patients with aneurysmal disease. Twenty-nine patients were available for long-term evaluation. In patients who were hypertensive preoperatively, 64.0% experienced long-term cure or improvement. Cardiac and cerebral disease, lower extremity claudication, and the need for subsequent cardiovascular surgery occurred with substantial frequency during the follow-up period.

Aged↗
PubMed1979

Prevention of air embolism after mitral valve replacement with a porcine heterograft prosthesis.

The production of prosthetic valve incompetence during atriotomy closure is among the operative maneuvers utilized to prevent air embolism in mitral valve replacement. The leaflets of a porcine bioprosthesis may be retracted safely and effectively, thereby producing temporary valve incompetence, by placing three polypropylene sutures through the valve orifice and around the sewing ring to encircle the leaflets. These traction sutures are eaily pulled out through the atriotomy suture line after all air has been displaced from the heart. The technique has been effective, easily accomplished, and without complications.

Animals↗