Correlación clínica-hemodinámica de la clasificación de la NYHA4/WHO en enfermos con hipertensión arterial pulmonar idiopática. Sus implicaciones en la clínica, en el tratamiento y en el pronóstico a largo plazo / Clinical-hemodynamic correlation of the NYHA/WHO system in idiopathic pulmonary artery hypertension. Clinical, therapeutic and long-term prognosis implications

BACKGROUND: The most often used functional classification for categorizing the degree of cardiac disability in patients with chronic left ventricular failure is the NYHAN/WHO system. In Idiopathic Pulmonary Arterial Hypertension [I-PAH], this system although used, has not been studied in detail regarding pulmonary hemodynamic parameters association and for long-term prognosis in each of the NYHA/WHO classes. METHODS: We retrospectively, studied the NYHA/ WHO system in 83 I-PAH patients. Patients were separated according to the response in the acute vasodilator trial in responders [n = 30] and nonresponders [n = 53]. RESULTS: Classes I - II did not represent the minority population for I-PAH patients [58/83 = 60%]. Only mean right atrial pressure [mRAP] and mean pulmonary artery pressure [mPAP] were different among the NYHA/WHO functional classes [p < 0.000 and p <0.012; respectively]. I-PAH patients class I have the probability to be a responder 12.6 times more [CI 95.%: 4.59-40.62; p < 0.000]. The long-term mortality for class I patients was 0.%, for class II: 2.%, for class III: 28.% and for class IV: 63.% [p < 0.0001]. The follow-up change for one grade class of the NYHA/WHO classes at four years was noticed only in 20.% of the I-PAH patients. CONCLUSIONS: NYHA/WHO classes I-II did not represent the minority of I-PAH patients population as has been previously considered. Only mRAP and mPAP were different among the NYHA/WHO classes. The NYHA/ WHO system on the basis of mRAP and mPAP allows to separate classes I-II from III-IV. I-PAH patients class I have 12.6 times more the probability to be a responder and better long-term survival; irrespective of the treatment the prognosis seems to be excellent for this functional class group patients.

La resistencia vascular pulmonar calculada. Un parámetro incierto para la valoración de lacirculación pulmonar. Los métodos actuales para determinarla / Calculated pulmonary vascular resistance, is definitively a worthless variable. Current methods for a better definition

The term pulmonary vascular resistance [PVR] describes, in part, the forces opposing the flow across the pulmonary vascular bed. The equation traditionally used is based on the assumption that the pulmonary capillaries, as well as some others vessels in series behave like a Poiseuille resistance. This assumption implies a laminar type of flow of a homogeneous Newtonian fluid, however blood is not a Newtonian fluid and flow is pulsatile in the pulmonary circulation. Neglecting these factors [which only slightly undermines the application of the equation] and others as well [like distension and recruitment of the vessels], will, however, not give us a true clinically practical solution for the calculation of PVR, because the concept of the equation is only true or partially true for part of the pulmonary circulation. In other parts of the lung, flow depends mainly on the behaviour of capillaries as a Starling resistor. If we considered always pulmonary venous pressure [measured clinically as left atrial pressure or pulmonary wedge pressure] as the effective downstream pressure for the calculation of PVR and we ignore or disregard the existence of a significant [quot ]critical closing pressure[quot ] [whatever the cause] in the lung it will lead to additional erroneous concept regarding PVR calculations and, in addition for the real hemodynamic conditions of the pulmonary vascular bed. Because, at least two different models of perfusion exist in the lung it is inadmissible from a theoretical point of view to calculate PVR, based on only in one of these models. According to the present knowledge of the pulmonary circulation hemodynamics, an improved definition for the PVR could be obtained: 1. by a multipoint pulmonary vascular pressure/flow plot at high flows and 2. with the use of the pulmonary artery occlusion pressure [PAOP] in addition to the determination of the pulmonary wedge pressure technique [PWP], in order to establish the estimated downstream pressure of the pulmonary circulation at zero flow. Therefore, pulmonary hemodynamic determinations of the PVR are better defined with the analysis of the pressure-flow relationships in addition to the information derived from the PAOP/PWP measurements. However, if none of the previous pressure-flow relationships [in order to obtain the slope = PVR at high flows] or the effective downstream pressure measurements [in order to estimate the critical closing pressure at zero flow] are applied for the analy.

Síndrome de la válvula pulmonar ausente. Evolución, tratamiento y factores asociados a muerte / Absent pulmonary valve syndrome. Evaluation, surgical treatment and risk factors

From 1991 to 2003 were studied 33 cases with absent pulmonary valve syndrome (AVPS): 66% were female, with a medium age of 1.5 years old and 11 kg of weight. Twenty seven cases (82%) were associated to Tetralogy of Fallot. Fourteen patients (5 younger than 1 year old) had corrective surgery. After the surgery, one patient required ballon pulmonary valvuloplasty for pulmonary stenosis; another one required surgery for changing the pulmonary prothesis one and five years after the first surgery. The rest of the patients did not present important problems. The five year survival was 95.4% in patients older than 6 months and 30.1% in younger patients (p = 0.000). As factors associated to mortality were the age younger than six months old (p = 0.003) and mechanical ventilation (p = 0.001) in our population. We suggest to delay the surgery in this group of patients because no survival were seen with or without the surgery. In older children with symptoms, the surgery also must be delayed in order to avoid more interventions for changing the pulmonary prothesis.