Wells J Michael, Iyer Anand S, Rahaghi Farbod N, Bhatt Surya P, Gupta Himanshu, Denney Thomas S, Lloyd Steven G, Dell'Italia Louis J, Nath Hrudaya, Estepar Raul San Jose, Washko George R, Dransfield Mark T
From the Birmingham VA Medical Center, AL (J.M.W., H.G., S.G.L., L.J.D., M.T.D.); Department of Medicine (J.M.W., A.S.I., S.P.B., H.G., S.G.L., L.J.D., M.T.D.), Division of Pulmonary, Allergy, and Critical Care, Lung Health Center (J.M.W., S.P.B., M.T.D.), Division of Cardiovascular Disease (H.G., S.G.L., L.J.D.), and Department of Radiology (H.N.), University of Alabama at Birmingham; Division of Pulmonary and Critical Care Medicine (F.N.R., G.R.W.) and Department of Radiology, Harvard Medical School (R.S.J.E.), Brigham and Women's Hospital, Boston, MA; and Department of Electrical and Computer Engineering, Auburn University, AL (T.S.D.).
Circ Cardiovasc Imaging. 2015 Apr;8(4). doi: 10.1161/CIRCIMAGING.114.002546.
Chronic obstructive pulmonary disease causes significant morbidity and concomitant pulmonary vascular disease and cardiac dysfunction are associated with poor prognosis. Computed tomography-detected relative pulmonary artery (PA) enlargement defined as a PA to ascending aorta diameter ratio >1 (PA:A>1) is a marker for pulmonary hypertension and predicts chronic obstructive pulmonary disease exacerbations. However, little is known about the relationship between the PA:A ratio, pulmonary blood volume, and cardiac function.
A single-center prospective cohort study of patients with chronic obstructive pulmonary disease was conducted. Clinical characteristics and computed tomography metrics, including the PA:A and pulmonary blood vessel volume, were measured. Ventricular functions, volumes, and dimensions were measured by cine cardiac MRI with 3-dimensional analysis. Linear regression examined the relationships between clinical characteristics, computed tomography and cardiac MRI metrics, and 6-minute walk distance. Twenty-four patients were evaluated and those with PA:A>1 had higher right ventricular (RV) end-diastolic and end-systolic volume indices accompanied by lower RV ejection fraction (52±7% versus 60±9%; P=0.04). The PA:A correlated inversely with total intraparenchymal pulmonary blood vessel volume and the volume of distal vessels with a cross-sectional area of <5 mm(2). Lower forced expiratory volume, PA:A>1, and hyperinflation correlated with reduced RV ejection fraction. Both PA diameter and reduced RV ejection fraction were independently associated with reduced 6-minute walk distance.
The loss of blood volume in distal pulmonary vessels is associated with PA enlargement on computed tomography. Cardiac MRI detects early RV dysfunction and remodeling in nonsevere chronic obstructive pulmonary disease patients with a PA:A>1. Both RV dysfunction and PA enlargement are independently associated with reduced walk distance.
URL: http://www.clinicaltrials.gov. Unique identifier: NCT00608764.
慢性阻塞性肺疾病导致严重发病，同时肺血管疾病和心脏功能障碍与预后不良相关。计算机断层扫描检测到的相对肺动脉（PA）增宽定义为肺动脉与升主动脉直径比>1（PA:A>1），是肺动脉高压的一个标志物，并可预测慢性阻塞性肺疾病急性加重。然而，关于PA:A比值、肺血容量和心脏功能之间的关系知之甚少。
对慢性阻塞性肺疾病患者进行了一项单中心前瞻性队列研究。测量了临床特征和计算机断层扫描指标，包括PA:A和肺血管容积。通过心脏电影磁共振成像的三维分析测量心室功能、容积和尺寸。线性回归分析了临床特征、计算机断层扫描和心脏磁共振成像指标与6分钟步行距离之间的关系。对24例患者进行了评估，PA:A>1的患者右心室（RV）舒张末期和收缩末期容积指数较高，同时右心室射血分数较低（52±7%对60±9%；P=0.04）。PA:A与实质内肺血管总容积以及横截面积<5 mm²的远端血管容积呈负相关。较低的第一秒用力呼气容积、PA:A>1和肺过度充气与右心室射血分数降低相关。肺动脉直径减小和右心室射血分数降低均与6分钟步行距离缩短独立相关。
远端肺血管血容量减少与计算机断层扫描显示的肺动脉增宽有关。心脏磁共振成像可检测到PA:A>1的非重度慢性阻塞性肺疾病患者早期右心室功能障碍和重塑。右心室功能障碍和肺动脉增宽均与步行距离缩短独立相关。
