Right-sided heart failure and the use of diuretics

Cardiovascular-pulmonary interaction in chronic obstructive pulmonary disease with special reference to the pathogenesis and management of cor pulmonale

Chronic obstructive pulmonary disease (COPD), which here refers to a group of diseases that have in common the physiologic defect of airway obstruction, is often associated with severe hemodynamic consequences. This article provides an overview of cardiovascular function in COPD with emphasis on recent advances in detecting, quantifying, and treating pulmonary hypertension and its major cardiac complication, cor pulmonale.

Chronic cor pulmonale

Chronic cor pulmonale is defined as right heart hypertrophy and/or chronic right heart failure. There are many etiologies, but the common cause is increased right heart work from pulmonary hypertension. Etiology can be conveniently discussed by assuming two prototypes, the asphyxial or hypoxic type and the vascular obliterative type. A common cause of the asphyxial type is chronic obstructive pulmonary disease, and the obliterative type is represented by chronic pulmonary thromboembolic disease or primary pulmonary hypertension. Pathology is discussed, emphasizing the cardiac manifestations of chronic cor pulmonale including data of specific cardiac chamber size. An overview of hemodynamics is given, and the use and limitation of electrocardiography and chest x-rays are discussed. The exciting potential use of echocardiography for the serial non-invasive measurement of anatomical and pathophysiological features is outlined, along with the value of a careful physical examination and the proper utilization of laboratory tests in the diagnosis of chronic cor pulmonale. In the patient with the asphyxial type, the treatment of pulmonary infectious exacerbations, the role of corticosteroids, digoxin, diuretics, phlebotomy, bronchodilators (theophylline, beta adrenergic agonists, and anticholinergics), and long-term oxygen therapy is noted. The controversy surrounding the use of vasodilators and calcium blockers in these patients is discussed. Treatment aspects of the vascular obliterative type, including the role of vasodilators, calcium blockers, prostacyclin, anticoagulants, and overall strategy are discussed. A brief note is mentioned of the promising role of surgical therapy in chronic thromboembolic disease causing chronic cor pulmonale.

Noninvasive tests for responsiveness of pulmonary hypertension to oxygen. Prediction of survival in patients with chronic obstructive lung disease and cor pulmonale

Response of mean pulmonary artery pressure (PAP) to breathing oxygen for 24 hours was measured in 43 patients with chronic obstructive pulmonary disease and cor pulmonale (COPD-CP). Considering a greater than or equal to 5 mm Hg fall in PAP after breathing 28 percent oxygen for 24 hours to be a significant response to oxygen administration, 25 and 18 patients were identified as responders (R) and nonresponders (NR), respectively. Oxygen consumption at the end of a symptom-limited maximum exercise (Vo2 peak) and right (RVEF) and left ventricular (LVEF) ejection fractions by nuclide ventriculography (NVG) were also obtained, and the changes (delta) in RVEF and LVEF after 48 hours of oxygen breathing recorded. All patients were prescribed continuous long-term domiciliary oxygen therapy (CLTO) and followed up as outpatients. Thirty-three patients have completed the follow-up for three years or until their deaths. The R showed a markedly higher survival compared to the NR at 1, 2, and 3 years. A high Vo2 peak (greater than 6.5 ml min-1 kg-1) was significantly associated with R status and also predicted two- and three-year survival. A baseline EF or delta EF of right or left ventricles could not be used to predict either the response of PAP to O2 or the long-term survival, although delta LVEF was significantly higher in the R. Response of PAP to breathing O2 for 24 hours is a reliable indicator of at least three-year survival with CLTO, which can be predicted noninvasively by baseline Vo2 peak.

Controlled trial of furosemide therapy in infants with chronic lung disease

To study the effects of furosemide therapy in infants with chronic lung disease (CLD), a double-blind controlled trial was designed. Seventeen infants with evidence of CLD (oxygen requirements greater than 30% at greater than 3 weeks of age and chest radiographic findings consistent with CLD) were studied. Pulmonary function was measured immediately before, and after 48 hours and 7 days of treatment with furosemide (1 mg/kg/12 hr intravenously or 2 mg/kg/12 hr orally) or placebo. Clinical status improved in six of seven infants who received furosemide and in two of 10 infants who received placebo (P less than 0.002). In the furosemide group, ventilator and oxygen requirements decreased (P less than 0.003); minute ventilation, alveolar ventilation, and dynamic compliance increased; and venous admixture decreased (P less than 0.05). There were no significant changes in the placebo group. Our findings suggest that furosemide significantly improves lung function during therapy in infants with CLD and allows earlier weaning from ventilatory support and supplemental oxygen.

OP-1206, a prostaglandin E1 derivative. Effects of oral administration to patients with chronic lung disease

In order to assess the clinical effectiveness of an oral prostaglandin E1 derivative, OP-1206, five patients with chronic obstructive pulmonary disease and two with pulmonary fibrosis were studied from the standpoint of hemodynamics and nine others with chronic lung disease from the standpoint of respiratory function. Oral intake of OP-1206 resulted in a significant decrease in the pulmonary arterial pressure (p less than 0.01), total pulmonary vascular resistance (p less than 0.01), pulmonary arteriole resistance (p less than 0.01), and total systemic vascular resistance (p less than 0.05), and an increase in the cardiac index (p less than 0.05) and oxygen delivery (p less than 0.01) with insignificant changes of PaCO2, PaO2 and pH. There was no clinical improvement of lung function after OP-1206 intake. OP-1206 is a potent vasodilator, improving cardiac performance in patients with chronic lung disease and possibly preventing the progress of cor pulmonale in this kind of patient.

Hemodynamics at rest and during exercise after oral hydralazine in patients with cor pulmonale

Oral hydralazine has been shown to be effective in decreasing pulmonary arteriolar resistance and increasing cardiac output in some patients with primary pulmonary hypertension. To determine whether a similar response could be observed in patients with chronic cor pulmonale, the hemodynamic status before and after the oral administration of hydralazine (25 mg, then 50 mg every 6 hours for 48 hours) were evaluated in 12 patients at rest and in 8 during upright exercise. After hydralazine, there was an increase in cardiac output at rest, from 4.3 to 6.3 liters/min (p < 0.001), and reductions in arteriovenous oxygen difference, from 8.1 to 6.1 volume percent (p < 0.001), mean pulmonary arterial pressure, from 52 to 44 mm Hg (p < 0.01), and pulmonary arteriolar resistance, from 11.2 to 6.2 units (p < 0.0005). Similar hemodynamic changes occurred during exercise, including an increase in pulmonary arterial saturation from 27 to 39 percent (p < 0.001) and a decrease in total pulmonary resistance from 12.7 to 8.9 units (p < 0.01). Results of pulmonary function tests performed before and after hydralazine did not change with drug administration. These findings indicate that the lung vascular bed in some patients with cor pulmonale is capable of responding to hydralazine with a reduction in pulmonary resistance and an increase in cardiac output both at rest and during exercise.