Moderate Pulmonary Arterial Hypertension Research Articles

Age and Risk of Pulmonary Arterial Hypertension in Scleroderma*

To investigate whether age at disease onset is a risk factor for pulmonary arterial hypertension (PAH) in scleroderma. Scleroderma center. Seven hundred nine consecutive scleroderma patients who underwent echocardiography. The risk of PAH associated with age at disease onset was modeled as both a continuous and categorical variable. Risk estimates were adjusted for sex, race, scleroderma subtype, disease duration, smoking status, FVC, anticentromere and antitopoisomerase I antibody status. Overall, 274 patients (38.6%), 272 patients by Doppler echocardiography and 2 patients by M-mode echocardiography, had PAH at baseline or during follow-up. There were 114 patients with mild PAH (right ventricular systolic pressure [RVSP], 36 to 45 mm Hg), 66 patients with moderate PAH (RVSP, 46 to 55 mm Hg), and 92 patients with severe PAH (RVSP > or =56 mm Hg). A 52% increase in risk of PAH was demonstrated for every 10 years of age at disease onset (odds ratio [OR], 1.52; 95% confidence interval [CI], 1.31 to 1.76). In addition, there was a twofold greater risk of PAH (OR, 2.30; 95% CI, 1.32 to 3.99) for late-onset (age > or =60 years) vs earlier-onset (< 60 years) disease. These associations remained evident and were somewhat strengthened when the analyses were restricted to patients with moderate and severe PAH. We identified increasing age at scleroderma onset as a risk factor for PAH. Vigilance among these high-risk patients may provide an opportunity to intervene prior to development of irreversible pulmonary vascular disease.

Atenolol premedication in patients undergoing closed mitral commissurotomy.

Perioperative tachycardia is common in patients undergoing surgery. In patients with mitral valve stenosis, the tachycardia can precipitate congestive heart failure and pulmonary oedema. Efficacy of atenolol premedication (0.5 mg/kg) for haemodynamic stability was assessed in 37 patients undergoing closed mitral commissurotomy (Group I) and compared with 43 patients who did not receive it (Group II). Patients with mild aortic regurgitation, atrial fibrillation, mild to moderate pulmonary artery hypertension or severe pulmonary artery hypertension without right ventricular failure were all included in the study. All patients were premedicated with tablet diazepam 0.1 mg/Kg, on the previous night and on the day of surgery and intramuscular morphine 0.1 mg/kg and glycopyrrolate 0.2 mg 45 min before surgery. In addition, in group I, atenolol 0.5 mg / kg was administered at night and 2 hours prior to surgery. Anaesthesia was induced with thiopental, morphine, oxygen and isoflurane. Tracheal intubation was facilitated by pancuronium bromide 0.12 mg/kg. Maintenance was with morphine, isoflurane and nitrous oxide in oxygen. The study was confined to the periods of maximal anaesthetic and surgical haemodynamic stress like laryngoscopy, intubation, surgical incision and commissurotomy. For all periods of haemodynamic stress, heart rate was significantly lower in group I, (p<0.05) than Group II. Blood pressure variations were comparable in both the groups. A statistically significant (p<0.001) decrease in systolic, diastolic, and mean arterial pressures, were observed in patients of both groups before and during valvotomy. One patient in atenolol group experienced bradycardia of <45 beats per minute. This was not associated with hypotension and it was easily treated with atropine. This study documents that, selective ss - blockade with atenolol in patients undergoing closed mitral commissurotomy, ensure a predictable control of heart rate in the perioperative period.

Diagnosis of Pulmonary Arterial Hypertension and Pulmonary Embolism With Magnetic Resonance Angiography

Pulmonary magnetic resonance angiography (PMRA) has been proven to be accurate for the diagnosis of suspected acute or chronic pulmonary embolism (PE). Only limited data exist on the reliability of PMRA for the diagnosis of acute and chronic pulmonary artery hypertension (PAH). The aim of this study was to determine the accuracy of PMRA in the differentiation between patients suffering from PAH of varying etiologies. Fifty patients (21 women; mean [+/- SD] age, 52 +/- 16 years) were examined with gadolinium-enhanced PMRA for the evaluation of pulmonary artery (PA) disease. The diagnosis of PAH (ie, systolic PA pressure of > 35 mm Hg) was determined by Doppler echocardiography. The criteria for the diagnosis of chronic PAH by PMRA were dilated central PAs (diameter > 28 mm) and abnormal proximal-to-distal tapering of the PAs. The diagnostic criterion for acute and chronic PE was the presence of an intravascular filling defect. Chronic PAH was present in 18 patients, which was correctly identified by PMRA in 16 patients (sensitivity, 89%). All patients without PAH had normal findings on PMRA (specificity, 100%). Only 1 of 18 patients with normal findings on PMRA showed moderate chronic PAH (negative predictive value, 94%). PAH due to acute/subacute pulmonary thromboembolism (15 patients) was identified in all patients (sensitivity, 100%). Acute PAH was differentiated from chronic PAH in all cases by the detection of intravascular filling defects and the lack of abnormal proximal-to-distal tapering of PAs. PMRA is a promising noninvasive imaging modality for the identification of patients with acute or chronic PAH. This technique should be considered a sensitive and highly specific screening tool for suspected chronic PAH.

Canine biventricular performance during acute progressive pulmonary microembolization: Regional myocardial perfusion and fatty acid uptake

The cardiac output during acute pulmonary artery hypertension (PAH) may be compromised by right ventricular (RV) outflow obstruction, myocardial ischemia, or adverse ventricular interactions. To study the relative contributions of these mechanisms to impaired biventricular function during PAH, we injected 75 to 105-μm glass beads into the pulmonary vasculature of 11 dogs and correlated the hemodynamic alterations with changes in biventricular function. Biventricular ejection fractions and interventricular septal motion were evaluated by gated blood pool angiocardiograms. Regional myocardial blood flow (n = 8 dogs) was measured with microspheres, and regional myocardial fatty acid metabolism during PAH (n = 8 dogs) was assessed by measuring the regional myocardial extraction of the radioiodinated fatty acid analog, 15-(p-iodophenyl)-3-methylpentadecanoic acid (3m-PIP/PDA). Following microembolization, the mean pulmonary artery pressure increased from 14 ± 1 to 48 ± 2 mm Hg ( P < .001) and cardiac output decreased from 3.5 ± 0.3 to 2.6 ± 0.3 1 /min ( P < .05). Right ventricular volume increased and RV ejection fraction decreased progressively. Abnormal septal motion during PAH occurred in 5 of 11 dogs and was associated with decreased LV diastolic compliance. Right ventricular myocardial blood flow remained increased during PAH while the regional extraction of 3m-PIP/PDA was uniform throughout the heart. These findings suggest that during moderate PAH the canine cardiac output is limited by RV outflow obstruction and decreased LV diastolic compliance rather than by ischemia.

Syndrome de détresse respiratoire aiguë de l'adulte au cours des intoxications par la colchicine

Two cases of adult respiratory distress syndrome were treated in a series of 26 patients suffering from colchicine overdose. The syndrome appeared between the 24th and 72nd hours. It was characterized by the presence of interstitial as well as alveolar oedema seen on chest roentgenograms. Haemodynamic investigation showed a hyperkinetic state with moderate precapillary pulmonary arterial hypertension. In addition, multivisceral phenomena were observed in all cases. Post-mortem examination revealed interstitial and alveolar pulmonary oedema with haemorrhagic or macrophagic alveolitis often accompanied by hyaline membrane. The physiopathology of ARDS occurring in colchicine poisoning appeared to involve such different factors as infection, the presence of a state of shock and disseminated intravascular coagulopathy. The direct toxic action of colchicine on pneumocyte microtubules and the inhibition of surfactant production were a probable cause. The responsibility of colchicine in leukocyte aggregation remains to be determined.

Hemodynamic Effect of Hydralazine in Interstitial Lung Disease Patients with Cor Pulmonale: Immediate and Short-term Evaluation at Rest and during Exercise

Hydralazine was administered short-term to 13 patients who had stable interstitial lung disease (ILD), pulmonary arterial hypertension (PAH); mean pulmonary arterial pressure ( [PAP]=26 +/- 9 mm Hg), and cor pulmonale (CP). All patients were studied at rest and during exercise. After intravenous hydralazine at rest, there were statistically significant increases in cardiac index (CI) (p less than 0.001), arterial oxygen saturation (SaO2) (p less than 0.01), and mixed venous saturation (S-vO2) (p less than 0.01). Pulmonary vascular resistance (Rp) (p less than 0.005) and systemic resistance (Rs) decreased (p less than 0.001), and PAP did not change. During exercise, PAP did not change; however, CI (p less than 0.01), PaO2 (p less than 0.001), and S-vO2 (p less than 0.01) increased further. The increase in Rp was significantly reduced (p less than 0.01). After continuation of oral hydralazine therapy in 12 patients for 7 days, PAP at rest was not statistically different from control; Rp and Rs remained decreased (p less than 0.001). The same results were found for CI, PaO2, S-vO2, and Rs during exercise. Although PAP did not change from control values, the drug significantly reduced the increase in Rp (p less than 0.005). Vasodilator therapy with hydralazine could be useful in patients with stable ILD who have inflammation with minimal to moderate fibrosis and PAH and might be used as an adjunct to conventional therapy for ILD and CP.

The pulmonary venous wedge pressure in pulmonary arterial hypertension.

AbstractThe comparability of the main pulmonary artery pressure (PAP) and the pulmonary venous wedge pressure (PVWP) was assessed during cardiac catheterization in 89 patients with pulmonary artery hypertension (PAH) and increased pulmonary blood flow. Preliminary evaluation revealed a wide disparity between the 2 determinations.Fifty‐five pull‐back pressure recordings from branch‐to‐main pulmonary artery were analyzed. Twenty‐four percent (13/55) had systolic pressure gradients &gt;20 mm Hg. between branch and main pulmonary artery. When PVWP and only ipsilateral branch PAP were compared (n=48), diastolic and mean (m), but not systolic PVWP, correlated closely with branch PAP (r=0.77, r=0.73 and r=0.59, respectively). In 46 of 48 patients the PVWPm was not significantly greater than the ipsilateral PAP. Twenty‐nine of 30 patients with PVWPm &lt;30 mm Hg. had an ipsilateral PAPm &lt;40 mm Hg. In 15 patients with PVWPm between 30 and 39 mm Hg, there was a wide range (30–59 mm Hg) of PAPm. Three patients with PVWPm &gt;40 mm Hg. had severe PAH.It is concluded that: 1) hemodynamically significant branch‐to‐main PAP gradients are present in some patients with PAH and may result in erroneously high pulmonary arteriolar vascular resistance when calculated from main PAP; 2) properly performed PVWP determination can define the lower limit of mean pressure in the ipsilateral branch pulmonary artery; 3) a PVWPm &lt;30 mm Hg. usually indicates an ipsilateral PAPm &lt;40 mm Hg; 4) a PVWPm &gt;30 mm Hg. is compatible with either moderate or severe PAH; 5) correlation of PVWP with PAP is not related to pulmonary blood flow.

Mechanisms of O 2 transport in andean dogs

Using previously inserted catheters. 11 dogs native to high altitude (7.5 23 kg b.wt.) were studied standing and unsedated in Cerro de Pasco. Peru at 4350 meters. Hemoglobin (Hb). hemalocrit (Hct). O 2 and CO 2 contents, p O 2 , p CO 2 and pH were measured in simultaneously obtained arterial and mixed venous blood samples. Blood pressures were measured in the pulmonary artery and the left ventricle and cardiac output (0) was determined by dye dilution. Moderately higher values for Hb and Hct were found in these dogs. Hb O 2 affinity was no different than that found in sea level dogs: the P in the Andean dogs was 31.6 mm Hg at 38 C and pH of 7.4. Because of the low barometric pressure at 4350 m (458 mm Hg) the partial pressures of oxygen in inspired and in alveolar air were lower than at sea level: 84.3 and 56.4 mm Hg, respectively. Pa, and Pv, were 55.5 and 32.9 mm Hg while the Sao. and Svo. were 79.5 and 50.7, respectively. Marked hyperventilation was observed (Pace, 25.6 mm Hg). however. pH was normal. Cardiac output was normal (average 162 + 39 ml/min/kg). Moderate pulmonary arterial hypertension was observed in the presence of normal left ventricular end diastolic pressure suggesting increased pulmonary vascular resistance.

CURRENT CONCEPTS IN PEDIATRIC CARDIOVASCULAR SURGERY

AMONG the many interesting congenital cardiac malformations amenable to surgery today, four will be discussed, namely, coarctation of the aorta, ventricular septal defect, Tetralogy of Fallot, and transposition of the great vessels. Recommendations for surgical therapy are based on the experience at the Mayo Clinic. Coarctation of the aorta continues to be most satisfactorily treated by operation and the hospital mortality risk is extremely low. In general, the optimal age for surgery is about 10 to 12 years. Unusually severe systemic hypertension or cardiac enlargement constitute an indication for somewhat earlier surgery. When infants with isolated coarctation of the aorta show severe cardiac failure, and this certainly occurs although uncommonly, operation should be advised at that age. The risk even then is very low, but few cases may require reoperation at age 12 because of failure of adequate growth of the anastomosis. The indications for repair of ventricular septal defect must take into account the estimated size of the lesion and its hemodynamic effects. Patients with small ventricular septal defects who have normalsized hearts and normal electrocardiograms, that is, those without clinical evidence of significant hemodynamic derangement, are not advised by us to undergo repair of the defect at present. Patients with ventricular septal defect and mild or moderate pulmonary artery hypertension (that is, patients whose pulmonary artery pressure is less than 75% of systemic artery pressure) can be operated upon at essentially no hospital risk. Operation is clearly advisable in all of these patients. Patients with ventricular septal defect who have severe pulmonary artery hypertension associated with a large pulmonary blood flow (and thus with only mild elevation of pulmonary vascular resistance) can be operated upon with a low hospital mortality rate, in the neighborhood of 5%.