Biomedical subjects
Publications and source records attributed to I L Tonkin.
The evaluation of a patient with a heart murmur and congenital heart disease is diagnostically very challenging. Multiple advanced techniques aid in the diagnosis of simple and complex malformations. Interventional procedures and surgical corrections have allowed most patients to enjoy a good and productive lifestyle.
An 11-year-old renal transplant recipient was noted to have a bruit over her transplant graft 26 months post transplant and 17 months following percutaneous renal biopsy during an episode of rejection. Diagnosis of an arteriovenous (AV) fistula was made by ultrasound examination with Doppler flow and was confirmed with arteriography. The AV fistula was occluded by transcatheter embolotherapy with placement of a steel coil into the fistula from the renal vein approach. This procedure allowed nonsurgical closure of the AV shunt without significant change in renal function.
Splenomegaly associated with myelodysplastic disorders in children may be massive and can result in pancytopenia, abdominal discomfort, and respiratory distress. When these symptoms cannot be relieved by nonsurgical means, splenectomy may be indicated. Under such conditions, surgical splenectomy carries increased risks, as the thrombocytopenia is difficult to correct secondary to splenic sequestration. Additionally, the surgical anatomy is often distorted secondary to the massive spleen and dissection can be difficult. These factors can lead to uncontrollable hemorrhage. In an attempt to decrease intraoperative blood loss, the authors successfully performed preoperative splenic artery embolization in 11 of 12 children (age range, 1-11 years) with pancytopenia due to hypersplenism. Hypersplenism requiring surgical splenectomy was due to leukemia (n = 9), myelodysplastic syndrome (n = 1), immune thrombocytopenia (n = 1), and osteopetrosis (n = 1). Embolization was performed under general anesthesia, prior to surgery, with gelatin sponge particles alone, Gianturco coils alone, or a combination of polyvinyl alcohol sponge particles and Gianturco coils. Embolization allowed for safe surgical splenectomy.
Although long-term transfusion therapy is at least 90% effective in preventing recurrent strokes after an initial cerebrovascular accident in patients with sickle cell disease, it is unknown how long transfusion therapy should be continued. To address this question, we prospectively discontinued transfusions in 10 patients with sickle cell disease whose median duration of transfusion therapy after an initial stroke was 9 1/2 years (range 5 to 12 years). Before the transfusions were discontinued, patients were examined by cerebral angiography, magnetic resonance imaging of the head, neuropsychologic testing, electroencephalography, and a complete neurologic examination. Within 12 months after transfusion therapy was stopped, 5 of 10 patients had had an ischemic event. Three events caused relatively mild deficits in the same areas as those originally affected. Two were associated with massive intracranial hemorrhage, including one on the contralateral side of original involvement. An additional patient died suddenly of unknown causes. Of the four remaining patients, three declined to resume transfusion and are relatively well at greater than or equal to 18 months after therapy was stopped. The studies performed before transfusions were stopped were not predictive of recurrent stroke. The risk of recurrent cerebrovascular accident in this group was significantly greater than the estimated risk of 10% in patients who are receiving long-term transfusion therapy (p = 0.002). This adverse outcome suggests that patients with sickle cell disease who have had a stroke must receive long-term transfusion indefinitely or a suitable therapeutic alternative must be devised.
Although the majority of patients with polysplenia syndrome will present during infancy or childhood with congenital heart disease, 5% to 10% will have no cardiac disease; and the associated abnormalities may not be discovered until adulthood. Physicians should be familiar with the chest and abdominal radiographic findings so as not to confuse this syndrome with other, more common pathologic conditions in asymptomatic adult patients.
We report the first observation of choroid plexus hyperdensity depicted by CT in two newborns with aortic arch obstruction. Neither infant had intracranial hemorrhage or infarction demonstrated by autopsy or cranial ultrasonography. Although not proven, we believe that such hyperdensity in these two cases represents abnormal vascularity within the choroid plexus related to upper extremity hypertension.
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The field of interventional catheterization in congenital heart disease has seen an explosion in application and scope over the past 10 years. In some lesions, such as valvar pulmonic stenosis, the transcatheter approach has replaced surgery as the treatment of choice. Applications currently considered experimental will no doubt become standard therapy as experience is gained with their use. Being able to avoid or postpone surgery has emotional, aesthetic, and practical advantages to patients and their families. The role of the catheter interventionist will continue to grow as new technologies such as fiberoptics, lasers, and miniaturized electromechanical devices are incorporated.
The heterotaxic syndromes may manifest as complex disorders with multiple anomalies, which have been described in the polysplenia/asplenia syndromes, or as a single isolated anomaly. Clinically insignificant anomalies may be incidentally discovered and should be recognized. Early diagnosis in the prenatal and neonatal periods allows for early intervention and correction, particularly of cardiac anomalies. Chest radiography, sonography, CT, radionuclide imaging, and MR imaging are useful diagnostic tools in evaluating these patients.
We assessed the accuracy of angiography or digital subtraction angiography (DSA) in diagnosing malignancy in hepatic tumors in children. In addition, these results were correlated with sonographic and computed tomographic findings of the liver in selected patients. Twenty-seven patients with primary liver tumors were examined with celiac or selective hepatic arteriography. Sonography was performed in 15 and computed tomography in 15 of the 27 patients. Angiographic criteria for malignancy or benignancy were established. These findings were correlated with computed tomographic and sonographic findings of the liver vascularity in selected patients. The final pathologic diagnosis was established surgically or by percutaneous biopsy. Sonography and computed tomography can be used as the initial procedure for evaluating tumor size, location and hepatic vascularity. However, the exact vascular anatomy demonstrated by angiography in children is more accurate and is often needed prior to surgical resection of primary liver tumors.
Twenty children were evaluated with digital subtraction angiography (DSA) for renal vascular hypertension. IV DSA from a basilic vein approach was performed in four patients and femoral vein approach in two patients. Intraarterial DSA was performed in 14 patients with suspected renal vascular hypertension. Renal vein renin samples were obtained from 17 patients. Two renal artery angioplasties were performed in association with intraarterial DSA. IV DSA was diagnostic in five of six patients with one false-negative result for fibromuscular dysplasia of the tertiary vessels. Intraarterial DSA images were diagnostic in 14 of 14 patients, and renal vein renin results correlated well with DSA results. In 11 patients, DSA was performed as an outpatient (hospital day-care unit) procedure. Of the 20 patients evaluated, 13 patients had abnormal DSA findings which included a hypoplastic but functioning kidney in three patients, distal small vessel abnormalities in five patients, unilateral or peripheral renal artery stenosis in four patients, and middle aortic syndrome in one patient. DSA with renal vein renin samples can be used as a diagnostic procedure for the evaluation of renal vascular hypertension in children as well as adult patients. In addition, it is a useful tool for therapeutic vascular procedures in children.
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Intraarterial digital subtraction angiography (IA-DSA) was performed in 80 pediatric patients. Forty-four underwent arterial injections with digital filming techniques. Of the 130 injections, DSA imaging was good or excellent in 121, often allowing resolution of vessels 1 mm in size. Thirty-six of the 80 patients underwent cardiac evaluation with intra-cardiac injections. Improved contrast resolution with IA-DSA allowed the use of smaller catheters (3-4F) and smaller amounts of contrast material. Immediate availability of subtracted images (no film processing delay) resulted in shorter total procedure time. Outpatient studies are possible. IA-DSA provides several notable advantages for the pediatric patient.
There are many types of diagnostic imaging studies available for the evaluation of foregut duplication cysts. Esophagography may be helpful in confirming the presence of a mediastinal mass, explaining esophageal symptoms, or defining the location of a lesion, but it is rarely diagnostic. Digital subtraction angiography can successfully be used in place of pulmonary arteriography to define vascular anatomy. Computed tomography is often diagnostic, although the attenuation number may be slightly elevated and not that of water. Computed tomography will clarify the relationship of the mass to adjacent mediastinal structures, and may also assist in percutaneous guided aspiration. Surgical resection is often necessary in an infant because of respiratory distress with airway compromise. In asymptomatic patients with a round to oval, nonenhancing, thin walled, cystic mass demonstrated on CT, a thoracotomy may be avoided and the patients may be followed by chest radiography.
Rapid assessment of a patient with possible major peripheral vascular injury is essential to preserve limb function. Intravenous digital subtraction angiography (IV DSA) allows rapid evaluation of these patients without the need for intraarterial examination. We report our experience in 295 vessels studied by IV DSA for the evaluation of possible traumatic arterial injury to the extremities or neck. Of our study population requiring angiography (469 patients), 63.4% were appropriate candidates for IV DSA. Of the vessels studied by IV DSA, 93.6% required no further radiologic evaluation. A normal appearance on IV DSA study indicates no major vascular injury; patients with positive studies may proceed to surgery without further interventional assessment.
Surgical management of left ventricular outflow tract obstruction in patients with complete transposition of the great arteries and an intact ventricular septum is difficult. Direct resection of subpulmonary stenosis has not produced satisfactory results. Thus, relief of stenosis has been accomplished with valved conduits from the left ventricle to the pulmonary artery. Initially, conduit tissue valves were porcine in nature. More recently, human-origin conduit tissue valves have been employed. In this report, we describe an unusual complication in a child with complete transposition in whom a homograft valve conduit was placed from the left ventricle to the pulmonary artery to relieve subpulmonary stenosis. The leaflets became fixed in an open position. Thus, the conduit was converted to a functionally nonvalved communication. The subpulmonary stenosis regressed, allowing egress from both the natural outflow tract and the conduit.