B P9 C88 Pulmonary Hypertension Flashcards
This is the ratio of change in p nary artery pressure (ΔP) to mean pulmonary blood flow (Q) (L/min)
PVR = mean pulmonary artery pressure [mPAP]-left atrial pressure)/CO
The average pulmonary blood flow at rest is _____________ , and at any moment 300 mL/m 2 of blood is in the pulmonary circulation of which approximately ______ occupies capillaries.
3.5 L/min/m2
25%
Define pulmonary hypertension
Elevated mPAP greater than 20 mm Hg diagnosed by invasive right heart catheterization (RHC) measured supine at rest
Characteristics of Pre-capillary PH
mPAP
PAWP
PVR
mPAP > 20 mm Hg
PAWP </= 15 mm Hg
PVR >/= 3 WU
The most common form of PH that cardiologists will encounter in contemporary medical practice is in the setting of _________________
Left heart disease
This includes patients with left ventricular systolic or diastolic dysfunction, mitral valvular disease of any type, stiff left atrial syndrome, and LV outflow tract or aortic valvular lesions, including obstructive hypertrophic cardiomyopathy.Virtually any left heart structural or functional abnormality from the ascending aorta to pulmonary venous bed may predispose patients to post-capillary PH.
_______________________ overlapping pathophenotype that is characterized by pulmonary arterial remodeling due to chronic pulmonary venous hypertension
Combined pre and post capillary PH
Classification of PH among CHD cases
Type 1 PAH
Equation of Transpulmonary gradient
TPG = mean PA - PCWP
TPG < 12 mm Hg in postcapillary PH
TPG > 12 mm Hg in precapillary PH
_____________________ related to a pulmonary vascular disease affecting the pulmonary arterioles. Pulmonary arterial hypertension may be idiopathic or may be related to connective tissue disease, cirrhosis (porto-pulmonary hypertension), human immunodeficiency virus, or Eisenmenger syndrome.
Pulmonary arterial hypertension
Hemodynamic findings in severe PH
The presence of severe RV dysfunction, a severely elevated RA pressure, or a severely elevated PVR >6 to 7 Wood units is diagnostic of severe PH
Pulsus alternans on RV or PA tracing (similar to the aortic pulsus alternans) or a narrow PA pulse pressure (eg, 30/23) is diagnostic of severe RV failure.
Vasoreactivity testing should not be performed on 2 cases:
- Left HF
-it may increase pulmonary blood flow and thus PCWP leading to pulmonary edema - PH sec to Lung disease
-vasodilators worsen V/Q mismatch and hypoxemia
Rationale for vasodilator testing in PH
Treatment
Prognosis
Effect of vasodilator on hemodynamics
(1) Positive responders to vasodilator testing may respond to chronic oral calcium channel blocker therapy
(2) Positive responders have a better long-term prognosis;
(3) assess the hemodynamic tolerance to vasodilator therapy, that is, ensure that PCWP does not increase and CO and systemic pressure do not decrease with vasodilators.
Acute response to vasodilator testing
Drop of mean PA pressure by >/= 10 mmHg to a value <40 mmHg without a decrease in cardiac output; decrease in PA pressure and PVR by >/= 20%
Parameters to assess in vasodilator testing
(1) CO (CO generally increases with vasodilator therapy, except in severe RV failure with no contractile reserve)
(2) PCWP (an increase in PCWP unveils an overlooked left heart failure)
(3) O2 saturation (may drop in case of lung disease)
(4) RA pressure (may increase in case of severe RV failure that gets overwhelmed as vasodilators increase venous return)
(5) systemic blood pressure.
Why CHD with L>R shunts need vasodilator testing?
Patients with left-to-right shunt (ASD, VSD, and PDA) who have PH with a PA pressure >2/3 systemic pressure or PVR >2/3 SVR or >6 Wood units need to have vasoreactivity testing before correction of the shunt to ensure that PH is reversible, otherwise closing the shunt may be harmful
