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Cardio. CHF. Chap 38 > ACVIM PH > Flashcards

ACVIM PH Flashcards

1
Q

pulmonary hypertension is defined as:

Gold standard method for diagnosis:

in humans, PH has been defined as a mean PAP:

A

abnormally increased pressure within the pulmonary vasculature

direct assessment PAP (RHC)

≥25 mm Hg at rest

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2
Q

PH results from 4:

A
  1. increased pulmonary blood flow
  2. increased pulmonary vascular resistance
  3. increased pulmonary venous pressure
  4. combination
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3
Q

PH proposed clinical classification 6 groups (Table 4):

Group 1

A

pulmonary arterial hypertension (PAH)

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4
Q

Group 2

A

left-sided hear disease LHD

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5
Q

Group 3

A

respiratory disease/hypoxia

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6
Q

Group 4

A

pulmonary thromboemboli (PE/PT/PTE)

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7
Q

Group 5

A

parasitic disease (DirofilariaandAngiostrongylus)

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8
Q

Group 6

A

disorders multifactorial or unclear mechanisms

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9
Q

Group 1’

A

Pulmonary veno‐occlusive disease (PVOD) or pulmonary capillary hemangiomatosis (PCH)

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10
Q

echocardiography should be viewed as a clinical tool to help assess the probability that a dog has PH
rather than:

definitive diagnosis of PH requires:

echocardiographic findings always should be interpreted within the context of other clinical findings, especially the presence or absence of clinical signs suggestive of PH

What are the C/S associated with PH?

A

a definitive diagnostic test

RHC

syncope, r-CHF, respiratory distress at rest, activity terminating in resp. distress

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11
Q

estimating systolic PAP involves:

using the simplified Bernoulli Equation

validated methods to estimate RA pressure are unavailable in dogs, and therefore estimates of RA pressure are arbitrary and potentially flawed

A

quantifying peak tricuspid regurgitation velocity (TRV)
derivation of the pressure gradient (PG) bw RV & RA
using the simplified Bernoulli Equation

PG = 4 × velocity [m/s]2 + RA pressure estimate
estimate of RA pressure is added to the calculated PG

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12
Q

Echo findings:
In addition to TRV, several echocardiographic signs of PH aid probability assessment:

signs involve 3 anatomic sites:

A

(1) ventricles
Size/remodeling, IVS deviation

(2) pulmonary artery
enlargement and flow

(3) RA and caudal vena cava
size

TRV >3.4m/s
# anatomic sites
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13
Q

Class 2 dogs:

secondary to LHD requires fulfilling 2 additional echo. criteria:

A

(1) documentation of LHD (i.e. MV or aortic valvular dz/LV dysfunction) (2) unequivocal LA enlargement

because RHC and PAWP determination are performed rarely, LA enlargement is utilized as a crude surrogate for chronically increased PAWP and postcapillary PH

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14
Q

veterinary medical literature the degree or severity of PH has been classified as:
Mild
Moderate
Severe

categories based on PG derived from TRV (tricuspid regurgitation PG)

Categories cut-offs are arbitrary & potentially misleading
i.e. conventional definition dog with severe PH can be free of clinical signs, whereas a dog with moderate PH could be in right‐sided heart failure

Therefore, the panel does not advocate their use. Instead, severity of PH should be based on clinical findings (Table1)

A 
not recommended but used to be:
Normal PAP – 20-30mmHg
Mild PH - >35-50mmHg
Mod. PH >50-80mmHg
Severe >80mmHg

+5mmHg normal
+10mmHg impending R-CHF
+15mmHg R-CHF

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15
Q

PE findings:

split or loud second heart sound may be auscultated, with severe PH
Why?

A

diastolic heart murmur of PR occasionally is detected in patients with severe PH

delay in the closure of the pulmonic valve

right‐sided systolic murmur
right‐sided heart failure - distended abdomen
jugular vein distention

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16
Q

signs involve 3 anatomic sites:

(1) ventricles
(2) pulmonary artery
(3) RA and caudal vena cava

A

signs involve 3 anatomic sites:

(1) ventricles
RV hypertrophy, systolic dysfunction
LV underfilling
IVS flattening/deviation

(2) pulmonary artery
PA enlargement PA/Ao >1
enlargement and flow

(3) RA and caudal vena cava
RA enlargement
CVC enlrgement

17
Q

veterinary medical literature the degree or severity of PH has been classified as:
Mild
Moderate
Severe

Categories cut-offs are arbitrary & potentially misleading
i.e. conventional definition dog with severe PH can be free of clinical signs, whereas a dog with moderate PH could be in right‐sided heart failure

Therefore, the panel does not advocate their use. Instead,

A 
>35-50
50-80
>80
severity of PH should be based on:
clinical findings table
Echo probability table
18
Q

Strategies to decrease the risk of progression:

general:

A

a. Exercise restriction
b. Prevention of contagious respiratory pathogens, parasitic preventatives
c. avoidance of pregnancy (because of potential to exacerbate PH
and because of the possibility of transmission of genetic
contributors)
d. avoidance of high altitude and air travel
e. avoidance of nonessential wellness procedures

19
Q

Group 1:

Shunt closure or occlusion is recommended in dogs
provided the shunt is hemodynamically relevant (ie, cardiac remodeling is present or likely to develop)

What else must we discern before shunt closure?:

A

shunt is exclusively from left to right
or becomes so upon administration of pulmonary vasodilators

Tx of right-to-left shunting and having erythrocytosis:
periodic phlebotomy with fluid replacement
Hydroxyurea can be considered as an alternative to decrease RBC volume

20
Q

Group 1:

PDE5i?:

A

is recommended for group 1a, 1b, and 1c because
without treatment the prognosis is guarded to grave and no specific
treatment is available for underlying disease

Using PDE5i in dogs with group 1’ disorders may result in
fatal acute pulmonary edema as seen in some humans

21
Q

Group 2:

Tx
Should we add sildenafil?

Explain why?

A

LHD - decreasing postcapillary PH

*** because dogs with PH secondary to LHD, by definition, have postcapillary PH (with or without pre-PH), use of PDE5i is not recommended as first line treatment

Driving pressure: P1 (PAP 40mmHg) – P2 (LA 20mmHg) = 20mmHg
PD5i P1 (PAP 20mmHg) – (P2 (LA 20mmHg) = 0 driving pressure
=R-CHF

22
Q

Group 2:

sildenafil yes if..

A

cardiogenic pulmonary edema has been ruled out/treated

PDE5i are recommended for dogs with evidence of right-sided heart failure

PDE5i may be considered in dogs with exertional syncope without another identifiable cause

23
Q

Group 3:

Tx underlying respiratory disorder

PDE5i?

A

In people, for the same reasons noted for group 2 PH, the use of PH- specific treatments PDE5i for group 3 PH are not routinely recommended

In contrast, in dogs with group 3 PH, there may be benefit

In a recent study of dogs with diverse causes of group 3 PH, administration of PDE5i was the only independent predictor of survival in a multivariable analysis

A PDE5i is recommended in group 3 dogs

24
Q

Group 4 PH: PDE5i

A

may be considered in group 4a patients (acute massive PE/PT/PTE) with overt RV dilatation and RV systolic dysfunction

25
Q

Group 5 PDE5i:

A

2018 American Heartworm Society guidelines do not provide recommendations for PH-specific treatment
No peer-reviewed studies have investigated PH-specific tx HW

Tx w. PDE5i may be considered for dogs with:
Dirofilaria immitis infec.
Angiostrongylus vasorum

26
Q

Group 6 tx:

A

Because multifactorial mechanisms, it is critical that treatment targets each underlying pathologic mechanism

clinician also should be familiar with when PH-specific treatments are recommended within each group and integrate this information to formulate a final treatment plan

27
Q 
Adjunc. tx:
PDE3 pimo:
Milrinone IV pimo:
Tyrosin kinase inhibitor (toceranib):
L-arginine:
A

post-cap PH may occur)

a.a. needed to synth NO. One study showed sildenafil plus L-arginine more effective than sildenfil alone

28
Q

Using PDE5i in dogs with group 1’ disorders:

A

may result infatal acute pulmonary edema as seen in some humans

this may occur because higher blood flows are not accommodated by the fixed downstream obstruction in the veins, capillaries, or both.

recommendation is that PDE5i be initiated in the hospital in dogs with known or suspected PVOD and PCH, with close monitoring for development of acute pulmonary edema.

The drug should be withdrawn immediately if this complication occurs.

Because PVOD and PCH are most likely to be definitively diagnosed postmortem, a high index of suspicion antemortem will be required to maintain appropriate vigilance

Cardio. CHF. Chap 38 (15 decks)

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