Major vessel chronic thromboembolic pulmonary hypertension is potentially remediable by thromboendarterectomy. The diagnosis often has been delayed because a lung perfusion scan demonstrated modest defects thought to be incompatible with severe vascular obstruction. To define the relationships between perfusion scan abnormalities, angiographic findings, and hemodynamic data, we analyzed 25 consecutive patients with chronic major vessel thromboembolic pulmonary hypertension who subsequently underwent thromboendarterectomy. We found that the perfusion lung scan consistently caused us to underestimate the severity of pulmonary arterial obstruction as defined by pulmonary angiography. Furthermore, there was no significant correlation between the severity of hemodynamic compromise and the extent of obstruction defined by perfusion scan or angiogram. These findings suggest that, when pulmonary hypertension is known or suspected, the diagnosis of correctable, chronic major vessel obstruction should be pursued by angiography and hemodynamic assessment even though the perfusion scan may demonstrate only two segmental defects.
Seventeen children with oxygen-dependent bronchopulmonary dysplasia, right ventricular hypertrophy, and Doppler echocardiographic evidence of pulmonary hypertension were studied by cardiac catheterization. Fifteen of these patients had pulmonary hypertension when placed in room air; six of these 15 patients were shown to have large systemic-to-pulmonary collateral vessels. The hemodynamic responses to oxygen and hydralazine were evaluated. Five patients developed normal pulmonary artery pressure while receiving supplemental oxygen and were not studied further. Of the remaining ten patients, the six patients with large, hemodynamically significant collateral vessels all had deleterious reactions to hydralazine. Two of the four patients without collateral pulmonary circulation responded to hydralazine with further reductions in mean pulmonary artery pressure. Five of the ten patients who had persistent pulmonary hypertension while receiving oxygen have died. Cardiac catheterization and angiography may provide important diagnostic, therapeutic, and prognostic information in patients with pulmonary hypertension complicating bronchopulmonary dysplasia.
In 100 patients with chronic obstructive pulmonary disease (COPD), we found no significant correlation between simultaneous measurements of right ventricular ejection fraction, using radionuclide ventriculography, and pulmonary arterial pressure. There was, however, a weak but significant correlation between right ventricular ejection fraction and the pulmonary vascular resistance (r = 0.40, p<0.005). In 52 of these patients, 37 with pulmonary hypertension, right ventricular end-systolic volume index was 53 ± 21 ml·m and end-diastolic volume index was 86 ± 27 ml·m , compared with a calculated mean of 33 ml·m and 79 ml·m , respectively, for normal subjects. In 24 of these patients where the measurements were made at rest and on exercise, the mean right ventricular end-systolic volume increased from 66 ± 20 ml·m to 87 ± 32 ml·m , with an increase in right ventricular systolic pressure from 28 ± 9 mm Hg to 55 ± 15 mm Hg. Analysis of the slope of the right ventricular end-systolic pressure volume relationship at rest and on exercise suggested relatively normal right ventricular contractility in the majority of patients. Thus, in these patients with stable COPD, despite the presence of pulmonary hypertension, right ventricular contractility remained relatively normal.
We present a 30-year-old man with pulmonary hypertension after pulmonary embolism. Pulmonary angiography showed multiple stenoses in the pulmonary vascular tree. We treated four of these stenoses by balloon angioplasty in three sessions. Pulmonary artery pressure was reduced from 90/25 mm Hg (mean 46) to 78/13 mm Hg (mean 35) with concomitant increase of aortic pressure from 105/60 mm Hg (mean 75) to 134/68 mm Hg (mean 90). Pulmonary perfusion scintigraphy showed increase of perfusion in the treated segments. Two procedures were followed by transient segmental pulmonary edema, but no other complications were noted. We conclude that balloon angioplasty is a promising method of lowering pulmonary artery pressure and improving pulmonary perfusion in suitable cases of pulmonary hypertension secondary to pulmonary embolism.
Indomethacin is a potent agent in the treatment of premature labor, but its use has been limited because of concern about its constrictive effects on the fetal ductus arteriosus. To study these effects we used serial fetal echocardiography in 13 pregnant women in premature labor who received indomethacin according to three different dose schedules, ranging from 100 to 175 mg per day, for a maximum of 72 hours. The gestational ages of the fetuses ranged from 26.5 to 31.0 weeks. The detection of ductal constriction in 7 of the 14 fetuses by echocardiography led to the discontinuation of indomethacin. Three fetuses also had tricuspid regurgitation. There was no statistically significant difference between the mean (±SEM) gestational age of the fetuses with ductal constriction and that of those without constriction (29.3±0.59 and 28.4±0.52, respectively). There was no relation between serum indomethacin levels in the mothers and ductal constriction. In all seven fetuses affected, ductal constriction had resolved by the time they were restudied 24 hours after the discontinuation of indomethacin. Persistent fetal circulation was not detected in any of the 11 neonates studied after delivery. Indomethacin used to treat premature labor appears to cause transient constriction of the ductus arteriosus in some fetuses, even after short-term use. (N Engl J Med 1988; 319:327–31.) IN the United States, premature delivery (before the 37th week of gestation) occurs in 7 percent of white women's pregnancies and 18 percent of black women's pregnancies. 1 Prematurity accounts for 75 percent of perinatal mortality. 2 Agents that have been used in the treatment of premature labor include alcohol, beta agonists (isoxsuprine, albuterol [salbutamol], terbutaline, and ritodrine), and magnesium sulfate. Beta agonists are the mainstay of current therapy. However, they have been associated with deleterious effects on the mother, including diabetic ketoacidosis, pulmonary edema, and myocardial ischemia. 3 4 5 These agents are therefore poorly suited for use in patients with various medical complications . . .
Relationships between pulmonary artery blood velocity patterns and elevated pulmonary artery pressure and resistance were studied in an animal model of chronic pulmonary hypertension. Monocrotaline pyrrole was injected into the right atria of 1-3-day-old lambs. The animals were subjected to an acute terminal study 4-6 weeks postinjection. Using an intraluminal 20-MHz pulsed Doppler probe, pulmonary blood velocity was measured at 2-mm intervals across the posterior-anterior axis, from which 2-D instantaneous velocity profiles were reconstructed and the characteristics of the waveforms examined. Preliminary computations indicate that the significant increase in pulmonary blood-flow reversal observed near the posterior wall in normal lambs with acute pulmonary hypertension created by hypoxia is not always present in animals with chronic pulmonary hypertension. However, the triangular shape of the waveform associated with pulmonary hypertension is apparent in all studies, and the maximum value of the ratio of reverse flow to forward flow calculated by sampling site correlated significantly with both pulmonary artery pressure and pulmonary vascular resistance.