Percent emphysema, airflow obstruction, and impaired left ventricular filling.
BACKGROUND
Very severe chronic obstructive pulmonary disease causes cor pulmonale with elevated pulmonary vascular resistance and secondary reductions in left ventricular filling, stroke volume, and cardiac output. We hypothesized that emphysema, as detected on computed tomography (CT), and airflow obstruction are inversely related to left ventricular end-diastolic volume, stroke volume, and cardiac output among persons without very severe lung disease.


METHODS
We measured left ventricular structure and function with the use of magnetic resonance imaging in 2816 persons who were 45 to 84 years of age. The extent of emphysema (expressed as percent emphysema) was defined as the percentage of voxels below -910 Hounsfield units in the lung windows on cardiac computed tomographic scans. Spirometry was performed according to American Thoracic Society guidelines. Generalized additive models were used to test for threshold effects.


RESULTS
Of the study participants, 13% were current smokers, 38% were former smokers, and 49% had never smoked. A 10-point increase in percent emphysema was linearly related to reductions in left ventricular end-diastolic volume (-4.1 ml; 95% confidence interval [CI], -3.3 to -4.9; P<0.001), stroke volume (-2.7 ml; 95% CI, -2.2 to -3.3; P<0.001), and cardiac output (-0.19 liters per minute; 95% CI, -0.14 to -0.23; P<0.001). These associations were of greater magnitude among current smokers than among former smokers and those who had never smoked. The extent of airflow obstruction was similarly associated with left ventricular structure and function, and smoking status had similar modifying effects on these associations. Percent emphysema and airflow obstruction were not associated with the left ventricular ejection fraction.


CONCLUSIONS
In a population-based study, a greater extent of emphysema on CT scanning and more severe airflow obstruction were linearly related to impaired left ventricular filling, reduced stroke volume, and lower cardiac output without changes in the ejection fraction.
Barr
R Graham
RG
Department of Medicine, College of Physicians and Surgeons, Columbia University, New York, NY 10032, USA. rgb9@columbia.edu
Bluemke
David A
DA
Ahmed
Firas S
FS
Carr
J Jeffery
JJ
Enright
Paul L
PL
Hoffman
Eric A
EA
Jiang
Rui
R
Kawut
Steven M
SM
Kronmal
Richard A
RA
Lima
João A C
JA
Shahar
Eyal
E
Smith
Lewis J
LJ
Watson
Karol E
KE
D000368:Aged; D000369:Aged, 80 and over; D000402:Airway Obstruction / Q000150:complications* / Q000503:physiopathology; D002302:Cardiac Output; D005260:Female; D005541:Forced Expiratory Volume; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D011656:Pulmonary Emphysema / Q000150:complications* / Q000000981:diagnostic imaging / Q000503:physiopathology; D012907:Smoking / Q000503:physiopathology; D013147:Spirometry; D013318:Stroke Volume; D014057:Tomography, X-Ray Computed; D018487:Ventricular Dysfunction, Left / Q000209:etiology* / Q000503:physiopathology; D014797:Vital Capacity