Sophia-Anastasia Mouratoglou (1), George Giannakoulas (1), Konstantinos Kouskouras (2), Haralambos Karvounis (1)(1) Department of Cardiology, Ahepa University Hospital, Aristotle University of Thessaloniki(2) Department of Radiology, Ahepa University Hospital, Aristotle University of Thessaloniki
A 67 year-old female was referred to our unit due to exertional dyspnoea, progressively increased over the last 10 months. Her medical history included asthma treated with bronchodilators for the last 30 years, diabetes mellitus, as well as an episode of acute pulmonary embolism five years ago.
On admission, patient was in WHO functional class III. On clinical examination she had elevated jugular vein pressure, while cardiac auscultation revealed an enhanced P2. Pulse oximetry showed low oxygen saturation SpO2 (84% on room air), which was further decreased on exertion (up to 75% in the end of 6MWT). NT-proBNP was 783pg/ml, while the rest of the laboratory tests were unremarkable. Arterial blood gas analysis revealed hypoxemia on room air (pO2 47mmHg, pCO2 30mmHg and SpO2 84%), which was rapidly corrected under supplemental O2 therapy (pO2 94mmHg, pCO2 34mmHg and SpO2 98%). Chest radiography revealed increased cardiothoracic ratio due to dilated right heart chambers and pruned peripheral pulmonary vessels more prominent in the upper pulmonary lobes. Echocardiography showed dilated right ventricle with reduced systolic function (TAPSE 1.3cm), moderate tricuspid regurgitation with a peak velocity of 5.06m/s (estimated right ventricular systolic pressure 110mmHg), flattened interventricular septum (left ventricular end-systolic eccentricity index 1.4), dilated right atrium and dilated inferior vena cava with reduced respiratory collapse (<50%) (Image 1).
According to echocardiographic findings, the patients’ probability of being diagnosed with pulmonary hypertension (PH) is:
The use of echocardiography is cornerstone in the evaluation of patients with exertional dyspnoea and should be performed in patients with suspected PH. Echocardiographic probability of PH in symptomatic patients is classified as low, intermediate or high, according to peak tricuspid regurgitation velocity (<2.8mmHg, between 2.9-3.4mmHg and >3.4mmHg) and the presence or not of other echocardiographic signs suggestive of PH, such as right ventricular dilatation and pressure and volume overload, increased right atrial dimensions and pressure or signs of pulmonary artery dilatation, etc (table 1). Based on our findings, the patient is classified as high risk of being diagnosed with PH. The correct answer is c.
What would you do next?
Based on echocardiographic findings, the patient is characterized as having high probability of being diagnosed with PH. Given the bad prognosis of the disease when left untreated (>10% 1-year mortality in high-risk patients), patients with possible disease should be further evaluated using a comprehensive set of examinations. The diagnosis of pulmonary hypertension is set hemodynamically with the use of right heart catheterization (RHC). According to current guidelines, RHC should be performed in selected patients, after the exclusion of the most common causes of PH (left heart disease, lung disease) and targeted medical therapy for PAH should be initiated only after the establishment of the PAH diagnosis. The correct answer is d.
According to current guidelines for the diagnosis of pulmonary hypertension (1), subsequent work-up was undertaken, following a stepwise process of non-invasive and invasive tests (Image 2). Lung function test revealed decreased diffusion lung capacity (DLCO 33% of predicted) with normal values of the rest of lung function parameters, serum immunology showed high ANA values, but detailed clinical evaluation failed to reveal signs of scleroderma, while high-resolution computed tomography (HRCT) of the chest demonstrated patchy areas of centrilobular ground-glass opacities, septal lines and mediastinal lymphadenopathy (Image 3). V/Q scan failed to demonstrate signs of chronic thromboembolic pulmonary hypertension. A right heart catheterization with vasoreactivity test was performed and the results are presented in Table 2. She underwent in six-minute walk test (6MWT) in which she walked 220m. Patient was diagnosed with non vasoreactive idiopathic pulmonary arterial hypertension (IPAH), prognosis was assessed according to current guidelines (Image 4), she was characterized as being intermediate to high risk and was put on anticoagulation and upfront combination therapy with oral ambrisentan 5mg OD and tadalafil 40 mg OD.
One month after the initiation of targeted medical treatment, patient presented clinical deterioration (WHO class IV) with low peripheral saturation (SpO2 70% on room air). Lung auscultation revealed bilateral crackles. Chest radiography was diagnostic of lung oedema with hilar hyperemia and Kerley B-lines and laboratory examination showed marked elevation of NT-proBNP levels compared to baseline (1500pg/ml).
According to patients’ presentation, what is the possible diagnosis?
Patient’s marked deterioration after initiation of targeted medical therapy sets the diagnosis of IPAH into consideration.
In the context of the questioning of the initial diagnosis, we reviewed the baseline HRCT that revealed centrilobular ground-glass opacities, septal lines and mediastinal lymphadenopathy. These findings are rarely seen in idiopathic pulmonary arterial hypertension, and are considered pathognomonic in PVOD with high specificity and sensitivity (85% and 75% respectively) (2-4). On the other hand, patient had very low DLCO value (33% predicted) in lung function test, low resting pO2, as well as low SpO2 during baseline 6MWT and experienced profound deterioration after the initiation of PAH advanced treatment. These findings have been shown to determinate a subgroup of patients with high probability of PVOD (3). Although the diagnosis of PVOD is set with the use of lung biopsy, the procedure is no longer recommended in most cases (1), as the combination of noninvasive examinations can help establish the diagnosis. On the basis of all the above, the diagnosis of PVOD was set. The correct answer is d.
What are the treatment options for the patient?
There is no established medical treatment for PVOD. The disease has very bad prognosis and lung transplantation is considered to be the treatment of choice (1). Advanced treatment for PAH may cause pulmonary oedema in these patients (3) and should be used cautiously in the setting of a PH center. Thus, clinical stabilization or even mild improvement has been described in case reports (5,6) and case series (7-9) of patients receiving iv epoprostenol. This approach has been proposed as bridge to lung transplantation (10) and may improve hemodynamics by increasing cardiac output and decreasing pulmonary vascular resistance (11). Based on patients’ clinical deterioration after the initiation of advanced PAH treatment, she was admitted to the ICU and oral targeted PAH medical treatment was immediately discontinued, while under high dose of iv diuretics and inotropic support, continuous iv epoprostenol was initiated as salvage therapy (gradually uptitrated to a maintenance dose of 28ng/kg/min), which resulted in marked hemodynamic improvement (Table 2). Patient was put on a transplant list and discharged from the hospital in stable clinical condition under high oral diuretic dose (furosemide 125mg OD), anticoagulation, supplemental O2 therapy and iv epoprostenol.
The diagnosis of PVOD is difficult to be set and is established by a combination of findings derived from clinical examination, HRCT and bronchoscopy. The physicians’ clinical suspicion and experience is the main guide in the diagnostic maze of PVOD. The identification of certain mutations, when available, can confirm the diagnosis of the heritable form of the disease. The prognosis is poor, and although lung transplantation is considered to be the best treatment option of PVOD patients, advanced treatment of PAH can be cautiously used always in the expense of a possible pulmonary oedema, in centers with experience in the management of this patient population.
It is considered that 5-10% of patients initially diagnosed with IPAH are misclassified patients with PVOD, as clinical and hemodynamic presentations are undistinguishable between these two clinical entities. In patients initially diagnosed with PAH that show no clinical improvement or present with clinical deterioration after the initiation of targeted PAH medical therapies, the diagnosis of PVOD may emerge and further work-up towards the direction of better classification should be made. Given that the diagnosis and management of patients with PVOD hide dangers and pitfalls, patients with the suspicion of PVOD should be early referred to expert centers with extensive experience in the disease.
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