ABC | Volume 113, Nº3, September 2019

Review Article Pulmonary Hypertension in General Cardiology Practice Daniela Calderaro, 1 J osé Leonidas Alves Junior, 2 Caio Júlio César dos Santos Fernandes, 2 Rogério Souza 2 Interdisciplinary Medicine in Cardiology Unit - Instituto do Coração, 1 São Paulo, SP – Brazil Pulmonary Circulation Unit- Instituto do Coração, 2 São Paulo, SP – Brazil Keywords Hypertension, Pulmonary; Pulmonary Heart Disease; Echocardiography/methods; Pulmonary Disease, Chronic Obstructive; Pulmonary Emphysema; Pulmonary Fibrosis. Mailing Address: Daniela Calderaro • Av. Dr. Eneas Carvalho de Aguiar, 44. Postal Code 05412-001, São Paulo, SP – Brazil E-mail: daniela.calderaro@incor.usp.br Manuscript received August 30, 2018, revised manuscript February 14, 2019, accepted March 20, 2019 DOI: 10.5935/abc.20190188 Abstract Thefindingofpulmonaryhypertension(PH)byechocardiography is common and of concern. However, echocardiography is just a suggestive and non‑diagnostic assessment of PH. When direct involvement of pulmonary circulation is suspected, invasive hemodynamic monitoring is recommended to establish the diagnosis. This assessent provides, in addition to the diagnostic confirmation, the correct identification of the vascular territory predominantly involved (arterial pulmonary or postcapillary). Treatment with specific medication for PH (phosphodiesterase type 5 inhibitors, endothelin receptor antagonists and prostacyclin analogues) has been proven effective in patients with pulmonary arterial hypertension, but its use in patients with PHdue to left heart disease can even be damaging. In this review, we discuss the diagnosis criteria, how etiological investigation should be carried out, the clinical classification and, finally, the therapeutic recommendations for PH. Introduction In the cardiologist's routine, the echocardiographic finding of pulmonary hypertension (PH) is extremely common. PH on echocardiogram can be identified in up to 2.8% of the general population 1 and in more than half of the patients with heart failure. It is estimated that almost 100% of the individuals with symptomatic mitral regurgitation and the majority of those with major aortic stenosis show some degree of increased systolic pulmonary artery pressure. 2,3 The diagnosis of PH has major prognostic implications, both when it is attributable to cardiovascular diseases, 4 and to pumonary diseases, 5 or even in isolated pulmonary vascular involvement. Unfortunately, it is common to initiate specific treatment indiscriminately for PH patients based only on echocardiographic data, which, in some cases, can increase mortality. 6 It is essential to perform detailed investigation to confirm the diagnosis and comprehension of the mechanisms predominantly involved in PH and, thus, determine the correct therapeutic approach. These topics will be discussed in this review. Definition Traditionally, PH is defined through invasive hemodynamic monitoring, with a recent review of the value assumed as pathological. Since 1973, the diagnosis of PH was arbitrarily made when mean arterial pulmonary pressure (mPAP) was equal to or greater than 25 mmHg. 7 However, recent data have shown that, even with lower mPAP values, there is an increase in mortality rates. 8 Therefore, on December 2018, a consensus resulting from the 6th World Symposium on Pulmonary Hypertension was published, which redefined PH to the situation in which mPAP is higher than 20 mmHg and pulmonary vascular resistance is greater than or equal to 3 Woods units. 9 When, in the presence of this level of pulmonary pressure, the pulmonary artery occlusion pressure (PAOP) is equal to or less than 15 mmHg, circulatory impairment begins to occur in the pulmonary circulation, either due to pulmonary arterial hypertension (PAH), or to pulmonary thromboembolism or pulmonary parenchymal disease. If the PAOP is higher than 15 mmHg, the PH is considered postcapillary. In this case, increased pressure in the pulmonary arterial territory is due to retrograde transmission of increased left atrial hydrostatic pressure into the pulmonary veins and pulmonary capillaries and, ultimately, into the pulmonary arterial circulation. There are situations in which the PAOP is above 15 mmHg, but this fact does not seem suficient to justifify the severity of mPAP increase. These patients display a pulmonary vascular resistance greater than 3Woods units and, usually, the diastolic pulmonary gradient is higher than 7 mmHg (GDP – the difference between the pulmonary artery diastolic pressure and the pulmonary capillary pressure). 10 This condition is called combined pre- and post-capillary PH. This hemodynamic profile can occur in patients with left heart disease and pulmonary vascular remodelling secondary to chronic congestion, but can also be seen in severely hypervolemic patients with PAH, and reverse Bernheim effect (when PH is so severe that results in the interventricular septum bulging toward the left ventricle, thus increasing the left ventricular pressure and, therefore, the PAOP). 11 Right heart catheterization is indispensable for the diagnosis of PH, with a morbidity of 1.1% and mortality of 0.055%, in experienced centers. 12 On the other hand, its implications for the accurateness of the diagnosis are overwhelming. In a study conducted at a referral center for PH in Brazil, 13 out of the 384 patients with echocardiography suggestive of PH undergoing right heart catheterization, only 78.6% actually had a mPAP ≥ 25 mmHg. Thus, if the diagnosis of PH is based on echocardiography alone, mistakes may occur in more than 20% of the cases. Moreover, in the same study, among the patients wih PH, 18.3% had post-capillary PH (PAOP > 15 mmHg), which has direct implications for the treatment. Without the catheterization, a quite considerable number of patients would be inadequately diagnosed and treated. 419