Left heart function in chronic obstructive lung disease

Metabolic and cardiorespiratory effects of decreasing lung hyperinflation with budesonide/formoterol in COPD: a randomized, double-crossover, placebo-controlled, multicenter trial

BACKGROUND

Studies suggest that acute decreases in lung hyperinflation at rest improves cardiac function and increases lung vascular perfusion from decompression of a compromised heart. In those studies, changes in resting oxygen uptake induced by medications, an alternative explanation for compensatory increased cardiac function, were not explored.

METHODS

This double-blind, multicenter, double-crossover study enrolled adults with chronic obstructive pulmonary disease, resting hyperinflation, and > 10% improvement in inspiratory capacity after 2 inhalations of budesonide/formoterol 160/4.5 μg. Metabolic, cardiac, and ventilatory function were measured 60 min pre-/post-dose at each visit. Primary endpoint was change in resting oxygen uptake for budesonide/formoterol versus placebo.

RESULTS

Fifty-one patients (median age: 63 years) received treatment. Compared with placebo, budesonide/formoterol significantly increased resting oxygen uptake (mean change from baseline: 1.25 vs 11.37 mL/min; P = 0.007) as well as tidal volume and minute ventilation. This occurred despite improvements in the inspiratory capacity, forced vital capacity, and expiratory volume in 1 s. No significant treatment differences were seen for oxygen saturation, respiratory rate, and resting dyspnea. There was a numerical increase in oxygen pulse (oxygen uptake/heart rate). Correlations between inspiratory capacity and oxygen pulse were weak.

CONCLUSIONS

Budesonide/formoterol treatment in resting hyperinflated patients with COPD results in significant deflation. The increase in oxygen uptake and minute ventilation at lower lung volumes, without changes in heart rate and with minimal improvement in oxygen pulse, suggests increased oxygen demand as a contributor to increased cardiac function.

TRIAL REGISTRATION

ClinicalTrials.gov identifier: NCT02533505.

Heart failure and COPD: partners in crime?

Chronic obstructive pulmonary disease (COPD) and heart failure (HF) are both common diseases with major impact and seem to coexist more frequently than expected from their separate population prevalences. However, estimates of combined prevalence must be interpreted carefully because of imperfections and difficulties in assessment of both diseases. This review aims to highlight HF prevalence in patients with COPD and vice versa, with a critical analysis of studies performed. First, definition, diagnosis, and prevalence of COPD and of HF will be discussed. Subsequently, an overview of important studies concerning combined prevalence with their limitations will be presented. Finally, pathogenic mechanisms and diagnostic considerations in clinical practice will be discussed.

Left atrial and ventricular filling in chronic obstructive pulmonary disease. An echocardiographic and Doppler study

Abnormal left ventricular (LV) diastolic function has frequently been reported in patients with chronic obstructive pulmonary disease (COPD). In the present work, diastolic function was studied by a combined analysis of pulmonary venous and mitral blood flow velocities in 34 patients with COPD clinically stable and without history of heart disease, and 20 control subjects. We confirmed the increased contribution of the atrial contraction to the LV filling in COPD patients in comparison with control subjects; furthermore, a decreased left atrial (LA) filling during the ventricular systole was observed. Changes in LV filling were not the consequence of a systolic dysfunction, because LV systolic function was normal. Doppler indices indicated that LA pressure was below 15 cm H(2)O in all the patients with COPD and control subjects. Several factors can be put forward to explain these changes; the first one is tachycardia. In addition to hypoxemia and medications, echocardiography suggested that a decreased LV preload participated in increased heart rate. Analysis of Doppler transmitral and pulmonary venous flows demonstrated the role of the ventricular interdependence because a correlation existed between LA and LV filling pattern and right ventricle pressure and diameter.

Echo-Doppler evaluation of left ventricular impairment in chronic cor pulmonale

The effects of acute right ventricular (RV) pressure and volume overloads on left ventricular (LV) filling are well known, while the significance of chronic RV pressure overload on LV function has been less studied. To evaluate the LV impairment, 30 patients with chronic cor pulmonale and pulmonary arterial hypertension secondary to chronic obstructive lung diseases (COLDs) were studied. All patients underwent respiratory tests and arterial blood gas assessment. An echo-Doppler examination was made to measure LV ejection fraction (EF), RV and LV end-diastolic and end-systolic diameters and areas, RV/LV area indexes, LV diastolic and systolic eccentricity indexes, mitral and tricuspid flow patterns, and mitral flow velocity in late and early diastole (A/E) indexes. A right heart catheterization was carried out to determine the resting mean pulmonary arterial pressure (mPAP). The data showed a marked enlargement of RV, compressing the left through a leftward shift of interventricular septum. A linear regression analysis detected a significant correlation between mPAP and the following parameters: RV/LV diastolic and systolic area indexes (r=0.75, p<0.0001; r=0.84, p<0.000, respectively), mitral A/E index (r=0.61, p<0.0005), and LV diastolic and systolic eccentricity indexes (r=0.93, p<0.0001; and r=0.83, p<0.0001). No correlations were found between echo-Doppler data and functional respiratory parameters. From these results, we conclude that chronic RV pressure overload induces LV filling impairment despite a normal systolic phase, due to septal leftward shift. In fact, chronic RV pressure overload distorts early diastolic LV geometry delaying LV filling phase, and the functional diastolic impairment of the LV is closely correlated to pulmonary hypertension levels.

Pathophysiological aspects of predominant preload lowering on pulmonary circulation, gas exchange, and the biventricular function in patients with chronic obstructive lung disease

A group of 21 patients with various degrees of chronic obstructive pulmonary disease underwent radionuclide ventriculography with hemodynamic monitoring to assess the extent to which pulmonary artery pressures and pulmonary vascular resistance can be lowered by the vasodilator molsidomine. Molsidomine (N-carboxy-3-morpholino-sydnonimin-ethylester) is similar to nitroglycerin in its mode of action. After hemodynamic and radionuclide data acquisition, at rest and during submaximal exercise in the steady state, 2 mg molsidomine was injected intravenously. Rest and exercise measurements were repeated 45 min after molsidomine injection. In patients with mild to moderate disease (group 1), pulmonary artery resting pressures decreased by 12% (p less than 0.05) at rest by 22% (p less than 0.01) during exercise after the administration of the drug. Total pulmonary resistance during exercise decreased significantly (p less than 0.01) as a result of marked decrease of pulmonary artery pressure (PAP) compared with a minimal decrease in cardiac index (CI). In patients with severe disease (group 2), only the resting values of PAP decreased while the relationship between pressure and flow was unchanged. During the exercise period, the preload parameters of the right and left ventricles decreased by an average of 30%. With regard to gas exchange, only the arterial PO2 at rest decreased slightly but significantly (p less than 0.05) after molsidomine, while the coefficient of oxygen delivery was not affected by the drug. However, in four patients arterial PO2 was markedly reduced by the drug. Right ventricular ejection fraction increased significantly (p less than 0.01) both at rest and during exercise in group 1 and during exercise in group 2 after administration of molsidomine.(ABSTRACT TRUNCATED AT 250 WORDS)