Understanding cardiopulmonary exercise testing
The cardiopulmonary exercise test (CPET) is an underutilized tool for evaluating patients with dyspnea of uncertain etiology. This is often due to the daunting task of trying to make sense of seemingly large amounts of interacting data, along with clinicians not having been taught a systematic approach for interpreting the results. Unlike other typical tests we order that point to a specific laboratory or anatomic radiographic abnormality, narrowing our differential to a few possibilities, one needs a different mindset when interpreting a CPET. This is a study to demonstrate the body’s normal or abnormal physiologic responses to increasing levels of physical stress. Because different conditions can give similar findings, the physiologic abnormalities must be interpreted in the context of the clinical presentation. If the results do not entirely fit the suspected diagnosis, they should be reported in a manner that may help guide the ordering physician down an alternate pathway. This CHEST NetWork has sought ways to reach out to members to promote a better understanding of the utilization of the basics of pulmonary physiology in the management of patients. We created an online two-part video demonstrating a basic systematic approach toward understanding the combinations of findings one often sees when performing a CPET. A comprehensive understanding cannot be shown in a 40-minute video series, but, hopefully, this will give a starting point to make this task easier and more enjoyable.
Zachary Morris, MD, FCCP
Steering Committee Member
Pulmonary Vascular Disease
BMPR2 mutation regulates singular millimetric fibrovascular lesions in bronchial circulation in PAH
Patients with PAH with BMPR2 mutation are younger with worse hemodynamics, ie, higher mean PAP with higher PVR and a lower cardiac index in comparison to the noncarriers. A systematic analysis of pulmonary imaging using CT angiography or magnetic resonance imaging in patients with PAH demonstrated increased bronchial arterial hypertrophy in BMPR2 mutation carriers compared with those without the mutation. Moreover, hemoptysis is more frequently encountered in patients with PAH with BMPR2 mutation and presumably related to bronchial artery remodeling and angiogenesis. French investigators described, in histopathology findings of explanted lungs of 44 patients with PAH (23 carriers of BMPR2 and 21 noncarriers), unusual singular millimetric fibrovascular lesions (SiMFi) in patients with BMPR2 mutations. The SiMFi is a structure of millimetric dimension with fibrovascular characteristics that are extremely rich in collagen and displayed more than one vascular channel. SiMFi did not show a classic glomeruloid pattern with predominant endothelial cell proliferation as seen in plexiform lesions but rather a large conglomerate of hypertrophic vessels. Performing an ink injection experiment in a freshly explanted lung highlighted a patent connection between bronchial/systemic vessels and pulmonary septal veins. SiMFis had an increased amount of bronchial microvessels and showed increased hypertrophy of larger bronchial arteries. SiMFi is directly related to hypertrophy and/or angiogenesis of vasa vasorum/bronchial arteries in the vicinity of the diseased artery. In patients with PAH with BMPR2 mutations, bronchial angiogenesis is more prevalent compared with patients with PAH lacking these mutations. This highlights the role of bronchial arteries in the spectrum of PAH.
Hector Cajigas, MD, FCCP
Sandeep Sahay, MD, FCCP
Steering Committee Members
1.Ghigna MR, et al. BMPR2 mutation status influences bronchial vascular changes in pulmonary arterial hypertension. Eur Respir J. 2016;48:1668. Epub 2016 Nov 3.
2. Tio D, et al. Risk factors for hemoptysis in idiopathic and hereditary pulmonary arterial hypertension. PLoS One. 2013;8:e78132.
3. Elliott CG, et al. Relationship of BMPR2 mutations to vasoreactivity in pulmonary arterial hypertension. Circulation. 2006;113:2509.
We have a lung cancer screening test but we could use it better
The American Lung Association recently demonstrated the majority of current and former smokers don’t know about lung cancer screening (LCS) with low-dose CT scanning.1 Researchers estimate less than 5% of eligible persons received LCS.2 Awareness campaigns targeting patients and health care providers at the local level can improve LCS uptake.3,4 While any new clinical practice has an expected implementation delay, LCS has another implementation barrier: complex eligibility criteria (age 55 – 80 years PLUS 30+ pack-year smoking history PLUS quit time less than 15 years). Electronic health record (EHR) tools might accelerate the adoption curve to identify eligible persons.5 Moreover, assessing and recording a qualitative smoking history is challenging, at best. One center showed 96.2% discordance between EHR smoking history and that obtained during shared decision-making visit for LCS.6 Mostly, the EHR underreported quantitative pack-year history; meaning LCS-eligible patients might fail to be identified by EHR review alone. Another small pilot showed that some patients age 55 – 79 years will update their EHR smoking history using patient portal, but this will not be effective for all patients.7 For current smokers, age alone may be an effective identification strategy, given the average start time for most smokers.8