Pulmonary arterial lesions in explanted lungs after transplantation correlate with severity of pulmonary hypertension in chronic obstructive pulmonary disease

https://doi.org/10.1016/j.healun.2012.11.014Get rights and content

Background

Pulmonary vascular findings are largely unreported in end-stage chronic obstructive pulmonary disease (COPD).

Methods

Pulmonary vascular lesions in explanted lungs from 70 patients with COPD/emphysema or α-1-antitrypsin deficiency were analyzed retrospectively. Patients were stratified by the presence and severity of pulmonary hypertension (PH) assessed by right-heart catheterization in 3 hemodynamically distinct groups: (1) non-PH (mean pulmonary arterial pressure [mPAP]<25 mm Hg), (2) mild to moderate PH (mPAP, 25–34 mm Hg), and (3) severe PH (mPAP≥35 mm Hg). The control group comprised 18 patients with idiopathic pulmonary arterial hypertension (IPAH). Vascular lesions were graded 1–6 according to a modified Heath and Edwards (HE) scale.

Results

All COPD patients were in New York Heart Association Functional Class III-IV (forced expiratory volume in 1 second, 23%±8%; total lung capacity, 128%±20% of predicted). Non-PH group: 30 patients (60% women) aged 54±6 years; mPAP, 17.2±3.8 mm Hg; median HE Grade 1 (range, 0–3), with medial hypertrophy of muscular pulmonary arteries and muscularization of pulmonary arterioles. Mild–moderate PH group: 30 patients (50% women) aged 53±6 years; mPAP, 28.6±2.8 mm Hg; median HE Grade 3 (range, 1–3), with additional cellular intimal proliferation. Severe PH group: 10 patients (50% women) aged 54±6 years; mPAP, 40.7±5.2 mm Hg; median HE Grade 3 (range, 2–5), with additional intimal fibrosis. IPAH controls: 18 patients (67% women) aged 36±4 years; mPAP,>50 mm Hg; median HE Grade 4 (range 3–6), with generalized arterial dilatation and plexiform lesions.

Conclusions

The extent of pulmonary vascular lesions in COPD correlate with the severity of PH. Morphologic lesions similar to those characteristic of IPAH can be observed as PH in COPD progresses to levels characteristic of IPAH.

Section snippets

Study population

This was a retrospective study of a randomly selected cohort of patients with COPD/emphysema and α-1-antitrypsin deficiency who underwent lung transplantation at the Copenhagen University Hospital, Rigshospitalet, Denmark, from January 1991 to January 2010. The main population has previously been extensively characterized.4 The lung transplant evaluation program for COPD at our institution includes right-heart catheterization (RHC). We analyzed the extent and severity of pulmonary vascular

Results

A total of 247 patients with COPD/emphysema or α-1-antitrypsin deficiency and a pulmonary capillary wedge pressure of≤15 mm Hg underwent lung transplantation (Figure 1). Of these patients, 154 (62.3%) had normal pulmonary pressures (non-PH) with mPAP<25 mm Hg, and 93 (37.7%) had PH characterized by mPAP≥25 mm Hg, of whom 83 had mild–moderate PH (mPAP 25–34 mm Hg), and 10 had severe PH (mPAP≥35 mm Hg).

Thirty patients were randomly selected from the 154 non-PH patients. Similarly, 30 patients

Discussion

The present study identified pulmonary vascular changes as an important component of COPD-related PH. Structural changes were observed prevalent at all stages of the disease and correlated with the degree of PH. In a small sub-set of patients with severe PH, in whom pulmonary pressures approached those characteristic of IPAH, vascular lesions were observed and included plexiform lesions, pulmonary hemosiderosis, and angiomatoid lesions.

Disclosure statement

This study received support from the Jacob & Olga Madsens Foundation and the Heart-Center Research Foundation.

None of the authors has a financial relationship with a commercial entity that has an interest in the subject of the presented manuscript or other conflicts of interest to disclose.

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