(1/595) Prediction of life expectancy in patients with primary pulmonary hypertension. A retrospective nationwide survey from 1980-1990.
Primary pulmonary hypertension (PPH) is a progressive disease of unknown etiology usually followed by death within 5 years after diagnosis. Although heart-lung or lung transplantation is now offered to patients with advanced PPH, adequate criteria assessing an accurate prediction of life expectancy in PPH has been difficult to establish. The aims of this study were to identify the characteristic features associated with a poor prognosis in patients with PPH, and to attempt to establish an individual prognostic index that predicts with great accuracy survival or death of PPH after one year, thereby helping to define criteria for patient selection for transplantation. In 1991, a retrospective nation-wide survey on PPH was conducted in Japan, and the clinical and cardiorespiratory variables of 223 PPH cases (female; 144, male; 79) in the period from 1980-1990 were obtained. The mean pulmonary arterial pressure (PPA) was 57.5+/-17.2 mm Hg (mean+/-SD), and the overall median survival time was 32.5 months since the first diagnostic catheterization. The characteristic features of 61 patients who died within one year of catheterization (Nonsurvivors group) were compared to 141 patients who survived one year or more from the time of catheterization (Survivors group). Among several clinical and cardiorespiratory variables, heart rate, PPA, right atrial pressure (PRA), stroke volume index (SI), pulmonary vascular resistance, and partial pressure of carbon dioxide (PaCO2) were significantly different between the two groups. As the independent factors, PPA, PRA, SI, and PaCO2 were selected for the multiple logistic analysis. Using a 0.7 probability cut-point to separate Nonsurvivors from Survivors, 84.6% of Nonsurvivors and Survivors could be correctly predicted from this logistic regression equation. Predictive equations like the present preliminary one can be used in the future to better assess life expectancy in patients with PPH in whom transplantation will be considered. (+info)
(2/595) Pulmonary capillary perfusion: intra-alveolar fractal patterns and interalveolar independence.
Pulmonary capillary perfusion was analyzed from videomicroscopic recordings to determine flow switching characteristics among capillary segments in isolated, blood-perfused canine lungs. Within each alveolus, the rapid switching pattern was repetitive and was, therefore, nonrandom (fractal dimensions near 1.0). This self-similarity over time was unexpected in a network widely considered to be passive. Among adjacent alveoli, the relationship among the switching patterns was even more surprising, for there was virtually no relationship between the perfusion patterns (coefficients of determination approaching zero). These findings demonstrated that the perfusion patterns in individual alveolar walls were independent of their next-door neighbors. The lack of dependence among neighboring networks suggests an interesting characteristic: the failure of one alveolar-capillary bed would leave its neighbors relatively unaffected, a feature of a robust design. (+info)
(3/595) Effect of intensive therapy for heart failure on the vasodilator response to exercise.
OBJECTIVES: The purpose of the study was to evaluate the lower extremity vascular responsiveness to metabolic stimuli in patients with heart failure and to determine whether these responses improve acutely after intensive medical therapy. BACKGROUND: Metabolic regulation of vascular tone is an important determinant of blood flow, and may be abnormal in heart failure. METHODS: The leg blood flow responses were measured in 11 patients with nonedematous class III-IV heart failure before and after inpatient medical therapy and in 10 normal subjects. Venous occlusion plethysmography was used to measure peak blood flow and total hyperemia in the calf after arterial occlusion and also after isotonic ankle exercise. Measurements were repeated following short-term inpatient treatment with vasodilators and diuretics administered to decrease right atrial pressure (18+/-2 to 7+/-1 mm Hg), pulmonary wedge pressure (32+/-3 to 15+/-2 mm Hg), and systemic vascular resistance (1581+/-200 to 938+/-63 dynes.s.cm(-5), all p < 0.02). RESULTS: Leg blood flow at rest, after exercise, and during reactive hyperemia was less in heart failure patients than in control subjects. Resting leg blood flow did not increase significantly after medical therapy, but peak flow after the high level of exercise increased by 59% (p = 0.009). Total hyperemic volume in the recovery period increased by 73% (p = 0.03). Similarly, the peak leg blood flow response to ischemia increased by 88% (p = 0.04), whereas hyperemic volume rose by 98% (p = 0.1). CONCLUSIONS: The calf blood flow responses to metabolic stimuli are blunted in patients with severe heart failure, and improve rapidly with intensive medical therapy. (+info)
(4/595) Combined effects of nitric oxide and oxygen during acute pulmonary vasodilator testing.
OBJECTIVES: We compared the ability of inhaled nitric oxide (NO), oxygen (O2) and nitric oxide in oxygen (NO+O2) to identify reactive pulmonary vasculature in pulmonary hypertensive patients during acute vasodilator testing at cardiac catheterization. BACKGROUND: In patients with pulmonary hypertension, decisions regarding suitability for corrective surgery, transplantation and assessment of long-term prognosis are based on results obtained during acute pulmonary vasodilator testing. METHODS: In group 1, 46 patients had hemodynamic measurements in room air (RA), 100% O2, return to RA and NO (80 parts per million [ppm] in RA). In group 2, 25 additional patients were studied in RA, 100% O2 and 80 ppm NO in oxygen (NO+O2). RESULTS: In group 1, O2 decreased pulmonary vascular resistance (PVR) (mean+/-SEM) from 17.2+/-2.1 U.m2 to 11.1+/-1.5 U.m2 (p < 0.05). Nitric oxide caused a comparable decrease from 17.8+/-2.2 U.m2 to 11.7+/-1.7 U.m2 (p < 0.05). In group 2, PVR decreased from 20.1+/-2.6 U.m2 to 14.3+/-1.9 U.m2 in O2 (p < 0.05) and further to 10.5+/-1.7 U.m2 in NO+O2 (p < 0.05). A response of 20% or more reduction in PVR was seen in 22/25 patients with NO+O2 compared with 16/25 in O2 alone (p = 0.01). CONCLUSIONS: Inhaled NO and O2 produced a similar degree of selective pulmonary vasodilation. Our data suggest that combination testing with NO + O2 provides additional pulmonary vasodilation in patients with a reactive pulmonary vascular bed in a selective, safe and expeditious fashion during cardiac catheterization. The combination of NO+O2 identifies patients with significant pulmonary vasoreactivity who might not be recognized if O2 or NO were used separately. (+info)
(5/595) Atrial arrhythmia after surgical closure of atrial septal defects in adults.
BACKGROUND: Atrial flutter and atrial fibrillation are causes of morbidity in adults with an atrial septal defect. In this study, we attempted to identify risk factors for atrial flutter and fibrillation both before and after the surgical closure of an atrial septal defect. METHODS: We searched for preoperative and postoperative atrial flutter or fibrillation in 213 adult patients (82 men and 131 women) who underwent surgical closure of atrial septal defects because of symptoms, a substantial left-to-right shunt (ratio of pulmonary to systemic blood flow, >1.5:1), or both at Toronto Hospital between 1986 and 1997. RESULTS: Forty patients (19 percent) had sustained atrial flutter or fibrillation before surgery. As compared with the patients who did not have atrial flutter or fibrillation before surgery, those who did were older (59+/-11 vs. 37+/-13 years, P<0.001) and had higher mean pulmonary arterial pressures (25.0+/-9.7 vs. 19.7+/-8.2 mm Hg, P=0.001). There were no perioperative deaths. After a mean follow-up period of 3.8+/-2.5 years, 24 of the 40 patients (60 percent) continued to have atrial flutter or fibrillation. The mean age of these patients was greater than that of the 16 who converted to sinus rhythm (P=0.02). New-onset atrial flutter or atrial fibrillation was more likely to have developed at follow-up in patients who were older than 40 years at the time of surgery than in those who were 40 or younger (5 of 67 vs. 0 of 106, P=0.008). Late events (those occurring more than one month after surgery) included stroke in six patients (all but one with atrial flutter or fibrillation, one of whom died) and death from noncardiac causes in two patients. Multivariate analysis showed that older age (>40 years) at the time of surgery (P=0.001), the presence of preoperative atrial flutter or fibrillation (P<0.001), and the presence of postoperative atrial flutter or fibrillation or junctional rhythm (P=0.02) were predictive of late postoperative atrial flutter or fibrillation. CONCLUSIONS: The risk of atrial flutter or atrial fibrillation in adults with atrial septal defects is related to the age at the time of surgical repair and the pulmonary arterial pressure. To reduce the morbidity associated with atrial flutter and fibrillation, the timely closure of atrial septal defects is warranted. (+info)
(6/595) Influence of pulmonary capillary wedge pressure on central apnea in heart failure.
BACKGROUND: Recent studies suggest that acute pulmonary congestion induces hyperventilation and that hyperventilation-related hypocapnia leads to ventilatory control instability and central sleep apnea. Whether chronic pulmonary congestion due to congestive heart failure (CHF) is associated with central apnea is unknown. We hypothesized that CHF patients with central apnea would have greater pulmonary capillary wedge pressure (PCWP) than patients without central apnea and that PCWP would correlate with central apnea severity. METHODS AND RESULTS: Seventy-five stable CHF patients underwent right heart catheterization and, on the basis of overnight sleep studies, were divided into central apnea (n=33), obstructive apnea (n=20), or nonapnea groups (apnea-hypopnea index [AHI] <5 events per hour). Mean PCWP was significantly greater in the central than in the obstructive and nonapnea groups (mean+/-SEM [range]: 22. 8+/-1.2 [11 to 38] versus 12.3+/-1.2 [4 to 21] versus 11.5+/-1.5 [3 to 28] mm Hg, respectively; P<0.001). Within the central apnea group, PCWP correlated with the frequency and severity of central apnea (AHI: r=0.47, P=0.006) and degree of hypocapnia (PaCO2: r=-0.42, P=0. 017). Intensive medical therapy in 7 patients with initially high PCWP and central apneas reduced both PCWP (29.0+/-2.6 [20 to 38] to 22.0+/-1.8 [17 to 27] mm Hg; P<0.001) and central apnea frequency (AHI) (38.5+/-7.7 [7 to 62] to 18.5+/-5.3 [1 to 31] events per hour; P=0.005). CONCLUSIONS: PCWP is elevated in CHF patients with central apneas compared with those with obstructive apnea or without apnea. Moreover, a highly significant relationship exists between PCWP, hypocapnia, and central apnea frequency and severity. (+info)
(7/595) Pulmonary artery pressure variation in patients with connective tissue disease: 24 hour ambulatory pulmonary artery pressure monitoring.
BACKGROUND: The specific contribution of secondary pulmonary hypertension to the morbidity and mortality of patients with underlying lung disease can be difficult to assess from single measurements of pulmonary artery pressure. We have studied patients with secondary pulmonary hypertension using an ambulatory system for measuring continuous pulmonary artery pressure (PAP). We chose to study patients with connective tissue disease because they represent a group at high risk of pulmonary vascular disease, but with little disturbance of lung function. METHODS: Six patients (five with progressive systemic sclerosis and one with systemic lupus erythematosis) were studied. They underwent preliminary cardiopulmonary investigations followed by Doppler echocardiography, right heart catheterisation, and ambulatory pulmonary artery pressure monitoring to measure changes in pressure over a 24 hour period including during a formal exercise test. RESULTS: All patients had pulmonary hypertension as measured by Doppler echocardiography with estimated pulmonary artery systolic pressures of 40-100 mm Hg. Pulmonary function testing revealed virtually normal spirometric values (mean FEV1 86.9% predicted) but marked reduction in CO gas transfer factor (KCO 57.8% predicted). Exercise responses were impaired with mean VO2max 50.6% predicted. Ambulatory PAP monitoring indicated significant changes in pressures with variation in posture and activity throughout 24 hours. Resting PAP did not predict the change in PAP seen on exercise. CONCLUSION: Conventional methods of assessment of the pulmonary circulation based on single measurements in the supine position may underestimate the stresses faced by the right side of the circulation. This ambulatory system allows monitoring of pulmonary haemodynamics continuously over 24 hours during normal activities of daily living. These measurements may increase our understanding of the contribution made by secondary pulmonary hypertension to the morbidity and mortality of the underlying lung disease. (+info)
(8/595) Relation between plasma nitrate and mean pulmonary arterial pressure in ventricular septal defect.
BACKGROUND: Nitric oxide (NO) is known to modulate myocardial contraction and coronary tone, and its inhalation reduces pulmonary vascular resistance in patients with pulmonary hypertension. OBJECTIVES: To evaluate the pathophysiological role of NO in patients with a ventricular septal defect (VSD). PATIENTS: Twenty-nine children with VSD, nine of whom had undergone VSD closure surgery, and 14 patients with Kawasaki disease. The mean age of the VSD patients was 3.1 years (range, 2 months to 9 years). METHODS: Using high performance liquid chromatography, nitrate (a more stable NO oxidation product) was measured in plasma specimens of the patients undergoing cardiac catheterisation. RESULTS: Nitrate concentrations in the pulmonary artery bore a significant relation to mean pulmonary artery pressure, pulmonary to systemic systolic pressure ratio, and pulmonary to systemic flow ratio. CONCLUSIONS: The concentration of nitrate was in proportion to the increment in intravascular or cardiac pressure, indicating that endogenous NO is upregulated as a compensatory homeostatic attempt to reduce pulmonary pressure and blood flow. (+info)