The surgical decision in tetralogy of Fallot: weighing risks and benefits with decision analysis

The preferred management of the symptomatic infant less than 2 years of age with tetralogy of Fallot remains unsettled. In this study decision analysis was used to assess the risks and benefits of three courses of action: (1) primary intracardiac repair; (2) palliative operation in infancy and delayed intracardiac repair; and (3) treatment with propranolol in infancy and delayed intracardiac repair. For each action the likelihood was determined of three possible outcomes for the patient: (1) death, (2) poor surgical result, or (3) good surgical result. Each outcome was associated with an estimated life expectancy. The best action was defined as that resulting in the longest life expectancy. With use of previously reported data and those from experience at one institution, a range of probabilities was estimated for death before operation, surgical mortality, success of propranolol treatment and hemodynamic result of operation. The choice of action was affected most by the mortality of primary intracardiac repair and the likelihood of a good hemodynamic result from intracardiac repair. Less important factors were the outcome of a palliative operation and the likelihood of success with propranolol therapy. It was found that in the institution studied if the mortality rate of primary intracardiac repair is 10 percent or less, intracardiac repair should be performed; otherwise propranolol treatment, which allows delay in intracardiac repair, should be selected. Both alternatives are preferable to palliative operation. With decision analysis, the clinician can use probabilities and life expectancy appropriate to a given clinical setting in determining the best management for the infant with tetralogy of Fallot.     

Prognosis for the newborn with transposition of the great arteries

To determine the prognosis for the newborn with transposition of the great arteries, the clinical course of 112 consecutive neonates with dextro-transposition was reviewed. Patients were managed with balloon atrial septostomy at initial cardiac catheterization, palliative operation if needed in the 1st year of life and Mustard's intraatrial baffle repair.The 1st month of life was the period of greatest risk (8 percent mortality rate). Between balloon septostomy and baffle repair, 14 of 103 patients at risk (14 percent) either died or had a cerebrovascular accident. The mortality rate at baffle repair was 14 percent (10 deaths in 71 patients), and there were 3 late postoperative deaths. Actuarial analysis of the data indicates that with this plan of management, approximately 50 percent of newborns with transposition of the great arteries will survive 5 years with excellent function and an additional 15 to 20 percent will survive with one or more medical handicaps.     

Serial changes in markers of disease activity with corticosteroid treatment in sarcoidosis

Serial changes in various markers of disease activity with corticosteroid therapy were assessed in 12 patients with active sarcoidosis. After six weeks of treatment with 40 mg daily of prednisone, all but one patient demonstrated symptomatic and radiographic improvement. For the entire patient group, there were corresponding improvements in forced vital capacity, from 59.2 +/- 5.5 to 70.5 +/- 5.3 percent of the predicted value (p less than 0.001, Student paired t test), serum angiotensin-converting enzyme levels, from 66.0 +/- 12.1 to 28.2 +/- 4.0 U/ml (p = 0.003), 67gallium lung scanning scores, from 3.6 +/- 0.2 to 0.8 +/- 0.3 (p less than 0.001), serum gamma globulin levels, from 2.40 +/- 0.2 to 1.5 +/- 0.1 g/dl (p less than 0.001), and erythrocyte sedimentation rate, from 26.8 +/- 2.7 to 14.8 +/- 3.0 mm per hour (p less than 0.001). Changes in percent of bronchoalveolar lavage fluid lymphocytes were less impressive (from 28.7 +/- 4.9 to 21.2 +/- 5.1, p = 0.034), but the geometric mean number of bronchoalveolar lavage fluid-IgG-secreting cells decreased from 23,861 to 3,830 (p = 0.013). Serial evaluations in five patients treated with decreasing doses of alternate-day prednisone for an additional 10 1/2 months indicated that changes in 67gallium lung scanning scores corresponded most closely to the clinical course in five of five patients. Determination of serum angiotensin-converting enzyme levels also closely paralleled the clinical course in four of five patients, whereas the other parameters measured were more variable markers of clinical response. However, abnormalities of bronchoalveolar lavage fluid-IgG-secreting cells often persisted in the absence of clinically evident disease, and the percentages of bronchoalveolar lavage fluid lymphocytes were frequently normal in patients who responded subsequently to corticosteroids. Larger prospective studies are warranted to more extensively evaluate various measurements of disease activity, especially bronchoalveolar lavage fluid analysis, in sarcoidosis.     

Exercise assessment of sinoatrial node function following the Mustard operation

To screen for sinoatrial node dysfunction following the Mustard procedure for transposition of the great arteries, we studied the chronotropic response to graded maximal treadmill exercise in 29 patients at mean 6.7 years after operation. Although 93% of patients had normal resting heart rate (HR), 83% demonstrated significant depression of maximum HR and/or recovery HR after termination of exercise. These findings were similarly present among a subset of 13 patients with normal exercise tolerance. Resting and exercise-induced HR in 10 patients receiving chronic digoxin therapy were no different than in the 19 patients without medication. Sixteen patients with abnormal chronotropic responses to exercise had intracardiac electrophysiologic evaluation which confirmed sinoatrial node dysfunction in nine. Abnormal HR responses did not correlate with clinical symptoms, cardiac arrhythmias, or postoperative hemodynamics. Maximal exercise testing may be a sensitive noninvasive method to identify sinoatrial node dysfunction in postoperative children.     

Carotenoids and vitamin A: the effect of hypocholesterolemic agents on serum levels

Serum total carotenoid (STC) and vitamin A levels were done as part of the biochemical screening in comparative studies of lipid lowering agents in type Ila hyperlipoproteinemic patients. STC levels were reduced following bile acid sequestering agent administration (colestipol 30 g/d) by 30% (P less than 0.01). Clofibrate and avicel placebo had inconsistent and nonsignificant effects on the STC levels. Serum vitamin A levels were not significantly altered by any of the test agents. The STC level changes were not correlated with concomitant changes in low-density lipoprotein-cholesterol (LDL-C) during any of the treatment regimens. It is suggested that STC level changes are related to alterations in the absorption of carotenoids during bile acid sequestrant administration.     

Cardiovascular alterations in severe pregnancy-induced hypertension: acute effects of intravenous magnesium sulfate

The central hemodynamic effects of intravenous magnesium sulfate were studied in five patients with severe pregnancy-induced hypertension. All five patients had a Swan-Ganz and a radial artery catheter placed prior to initiation of magnesium sulfate therapy. Four grams of magnesium sulfate was given over 15 minutes followed by a continuous infusion of 1.5 gm per hour. There was a 12.5% increase in cardiac index immediately after the infusion but cardiac index returned to pretherapy values by 15 minutes after infusion. The mean arterial pressure was significantly (p less than 0.01) decreased 30 minutes after the 4 gm loading dose but had returned to baseline values by 1 hour. There were no other significant changes in any of the hemodynamic or oxygen-related variables measured. Our data confirm previous hemodynamic studies in patients with severe pregnancy-induced hypertension indicating a hyperdynamic state with large fluctuations in systemic and pulmonary vascular resistances. In addition, magnesium sulfate has been shown to have a transient hypotensive effect on mean arterial pressure, related to bolus infusion, that is not present with continuous infusion.     

Responses of the growth-retarded fetus to acute hypoxemia

Growth retardation in the human fetus associated with maternal cardiovascular disease is frequently accompanied by birth asphyxia and perinatal mortality. We have investigated the cardiovascular responses to acute hypoxemia in the fetal lamb with growth retardation secondary to embolization of the uteroplacental vascular bed. In the basal period, fetal arterial P_O2 and umbilical perfusion were significantly lower, and perfusion of the adrenal glands, brain, and heart was significantly higher, in embolized than in control fetal lambs. During imposed acute hypoxemia there was preferential perfusion of vital organs, the adrenal glands, brain, and heart in control and embolized fetuses. This preferential perfusion to the vital organs during hypoxemia was significantly more pronounced in embolized animals. Because of the increased compensation during acute hypoxemia, as reflected by the increased preferential perfusion of vital organs, the growth-retarded fetuses would probably decompensate sooner if the hypoxemia was prolonged.