ABSTRACT
Background: Fractional flow reserve (FFR) is the current gold standard for identifying myocardial ischemia in individuals with coronary artery stenosis. However, FFR is not penetrated as much worldwide due to time consumption, costs associated with adenosine, FFR-related discomfort, and complications. Resting physiological indexes may be widely accepted alternatives to FFR, while the discrepancies with FFR were found in up to 20% of lesions. The saline-induced Pd/Pa ratio (SPR) is a new simplified option for evaluating coronary stenosis. However, the clinical implication of SPR remains unclear. Objectives: In the present study, we aimed to compare the accuracies of SPR and resting full-cycle ratio (RFR) and to investigate the incremental value of SPR in clinical practice. Methods: In this multicenter prospective study, 112 coronary lesions (105 patients) were evaluated by SPR, RFR, and FFR. Results: The overall median age was 71 years, and 84.8% were men. SPR was correlated more strongly with FFR than with RFR (r = 0.874 vs. 0.713, respectively; p < 0.001). Using FFR < 0.80 as the reference standard variable, the area under the receiver-operating characteristic (ROC) curve for SPR was superior to that of RFR (0.932 vs. 0.840, respectively; p = 0.009). Conclusion: Saline-induced Pd/Pa ratio predicted FFR more accurately than RFR. SPR could be an alternative method for evaluating coronary artery stenosis and further investigation including elucidation of the mechanism of SPR is needed (225 words).
ABSTRACT
Chronic obstructive pulmonary disease (COPD) is a chronic inflammatory lung disease with obstructed airflow and frequently causes secondary mild-moderate pulmonary hypertension (PH). However, a low proportion (1%-5%) of COPD patients develop severe therapy-resistant PH, and it is crucial to determine whether the patient has another disease capable of causing severe PH, including pulmonary arterial hypertension.Here, we describe a case of a 71-year-old male with COPD complicated by severe PH and right heart failure. He had a history of heavy smoking and developed progressive hypoxemia on exertion. He had severe airflow limitation (forced expiratory volume % in one second, FEV 1.0% = 42.8%) with a markedly reduced diffusing capacity of the lung (predicted diffusion capacity of carbon monoxide, %DLCO = 29%), and high-resolution computed tomography (CT) demonstrated significant lung parenchymal abnormalities such as diffuse interlobular septal thickening, ground-glass opacities, and enlarged mediastinal lymph nodes. He was diagnosed with group 3 PH caused by COPD but resistant to the treatment of COPD, diuretics, and oxygen therapy. Pathohistological analysis of autopsy specimens revealed the coexistence of interstitial fibrosis and partial occlusion of the small intrapulmonary veins, which led to a conclusive diagnosis of pulmonary veno-occlusive disease (PVOD).Because of its rarity and similarity with idiopathic pulmonary arterial hypertension, PVOD is difficult to diagnose antemortem and has a poor prognosis. High-resolution CT findings (septal thickening, ground glass, and enlarged lymph nodes) and severely reduced DLCO should be carefully evaluated for the early detection and treatment of PVOD in COPD patients with severe PH.
