Exam 4: Hypertension Part II (Mar)

Question 1

World Health Organization (WHO) classifications on Pulmonary hypertension

Answer 1

1. Pulmonary arterial hypertension (PAH)
2. PH due to left heart disease
3. PH due to lung diseases and/or hypoxia
4. Chronic Thromboembolic pulmonary hypertension (CTEPH)
5. PH with unclear multifactorial mechanisms

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Question 2

Plumonary HTN
* definition
* S/S
* 3 hemodynamic profiles

Answer 2

mean pulmonary artery pressure (mPAP) >20 mmHg
* S/S: Accentuated S2 & S4 “gallop” heart sounds, LE swelling
* 3 hemodynamic profiles based on PAWP and PVR:
1. isolated precapillary PH
2. isolated postcapillary PH
3. combined pre & postcapillary PH

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Question 3

Precapillary PH definition

Answer 3

defined as PVR of ≥3.0 wood units w/o elevated LAP or PAWP (PAWP <15mmHg = normal)

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Question 4

Isolated postcapillary PH definition

Answer 4

• results from increased pulmonary venous pressure, usually d/t elevated LAP caused by valve disease or LV dysfunction
• Isolated postcapillary PH is characterized by a PAWP >15mmHg, w/normal PVR

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Question 5

Combined pre- and postcapillary PH definition

Answer 5

• (aka reactive PH) reflects chronic pulmonary venous HTN with secondary pulmonary arterial vasoconstriction and remodeling
• Characterized by a PAWP >15mmHg and a PVR > 3.0 WU
• Can be subcategorized as fixed or vasoreactive d/o the response to vasodilators, diuretics, or mechanical assistance

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Question 6

High flow PH definition

Answer 6

occurs w/o an elevation in PAWP or PVR and results from increased pulmonary blood flow caused by a systemic-to-pulmonary shunt or high cardiac output

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Question 7

Chart for hemodynamic definitions of PH

Answer 7

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Question 8

Pulmonary Artery HTN
* Diagnosis
* 4 mechanisms that increase mPAP

Answer 8

• Right heart catheterization is required for a dx, classification and tx plan
• Mechanisms that increase mPAP
  1) elevated resistance to blood flow within the arterial circulation
  2) increased pulmonary venous pressure from left heart disease
  3) chronically increased pulmonary blood flow
  4) a combination of these processes

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Question 9

PVR equation:
PH can result from abnormalities in the _ or _ components of the _ _ sometimes both

Answer 9

PVR = (mPAP − PAWP)/COP
* PH can result from abnormalities in the arterial or venous components of the lung circulation, sometimes includes contributions from both

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Question 10

Pulmonary Artery HTN
* what does a TEE show?
* Why get an Echo? whats the limitations?

Answer 10

• TTE reveals RA & RV enlargement
• Echocardiogram is commonly used to estimate pulmonary arterial systolic pressure (PASP) as a screening tool for PH
• Although echocardiographic PASP > 41 mmHg is relatively sensitive and specific for PH, it cannot provide the accurate mPAP for definitive diagnosis

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Question 11

Severity of PH classifications

Answer 11

• Once right heart cath is performed, the severity of PH determined:
• Mild PH (mPAP = 20–30 mmHg)
• Moderate PH (mPAP = 31–40 mmHg)
• Severe PH (mPAP >40 mmHg)
• normal pulmonary circulation can accommodate a fourfold increase in COP without a marked change in mPAP

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Question 12

• How many people does PH affect?
• Nearly 1:8 PAH pts have long term improvements with ___

Answer 12

15 ppl per million per year

• calcium channel blockers

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Question 13

• 3% of PAH cases are deemed _ , with mutations in __ __ _ receptor type 2 (BMPR2)
• The remaining cases are designated “__ __ ,” since they can be ascribed to manifestations of drugs, toxins, or other diseases

Answer 13

• 3% of PAH cases are deemed inheritable, with mutations in bone morphogenetic protein receptor type 2 (BMPR2)
• The remaining cases are designated “associated PAH,” since they can be ascribed to manifestations of drugs, toxins, or other diseases

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Question 14

• PAH was traditionally a disease of __ __, with median survival rate of 3 yrs, current data shows a demographic shift, now with __ __ and more ____ being diagnosed
• Despite improved diagnosis and therapy, 1-year mortality is ̴____%

Answer 14

• PAH was traditionally a disease of young women, with median survival rate of 3 yrs, current data shows a demographic shift, now with older pts and more men being diagnosed
• Despite improved diagnosis and therapy, 1-year mortality is ̴15%

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Question 15

Pulmonary Artery HTN
* development
* 3 main classifications of pulmonary vasodialator drugs
* What kind of therapy is often required?

Answer 15

• Sustained vasoconstriction and remodeling
• There are 3 main classes of pulmonary vasodilator drugs for PAH: Prostanoids, Endothelin receptor antagonists (ERAs), nitric oxide/guanylate cyclase pathways
• Combination therapy is often required for adequate tx of PAH

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Question 16

PAH treatment: Prostanoids and 4 agents

Answer 16

• mimic the effect of prostacyclin to produce vasodilation while inhibiting platelet aggregation.
• They also have anti-inflammatory effects
• epoprostenol (IV), iloprost (inhaled), treprostinil (SQ, IV, INH, PO), beraprost(PO)

All provide improvement, but only epoprostenol has been proven to reduce mortality

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Question 17

PAH Treatment: Endothilin receptor antagonists (ERA’s)

Answer 17

ERAs have been shown to improve hemodynamics and exercise capacity

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Question 18

PAH treament: Nitric oxide/guanylate cyclase

Answer 18

• nitric oxide produces pulmonary vasodilation by stimulating guanylate cyclase and cGMP formation in smooth muscle cells. This effect is transient because nitric oxide is quickly bound by hgb and degraded by phosphodiesterase type 5
• Continuously inhaled nitric oxide has been widely used in both perioperative and critical care settings, and preparations for home use have become available
• Chronic therapy has been directed toward PD-5 inhibitors

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Question 19

PAH preop considerations
* what procedures do we need to pay attention to?

Answer 19

• Consideration should be given to procedures with potential for: venous embolism, elevations in venous and/or airway pressure, hypoxic pulmonary vasoconstriction, reduction in pulmonary vascular volume, systemic inflammation, and emergency procedures

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Question 20

PAH preop considerations: S/S

Answer 20

• nonspecific sx of fatigue, dyspnea, and cough
• more advanced s/s: angina and syncope
• On physical exam: may exhibit a parasternal lift, accentuated S2, S3 and/or s4 gallop, JVD, peripheral edema, hepatomegaly, and ascites
• Rarely, compression of a dilated PA may lead to RLN damage and hoarseness

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Question 21

PAH preop considerations:

• For moderate/severe PH, what is recommended prior moderate or high risk surgery?
• What should also be performed because PAWP and LVEDP have potential discrepancies?

Answer 21

• right heart cath prior to moderate-high risk surgery is recommended
• left heart cath should also be performed in pts with coexisting left heart dz because inaccurate LVEDP may lead to misclassification of PH and inappropriate treatment

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Question 22

PAH preop considerations:
* ____testing with ____ is performed during right heart catheterization to determing responsiveness to vasodialator therapy
* ___-___% of PAH pts are unresponsive to inhaled nitric oxide, but those that are responsive to CCB’s may benefit from other tageted therapy

Answer 22

• Vasoreactivity testing, often with inhaled nitric oxide, is performed during right heart catheterization to determine responsiveness to vasodilator therapy
• 85–90% PAH pts are nonresponsive to inhaled nitric oxide, but those that are responsive also respond to CCBs and may benefit from other targeted therapy

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Question 23

Perioperative physiology:
* primary intraop goal
* cautions with what interventions
* what added perioperative complexities can have serious consequences? (7 complexities)

Answer 23

• goal is maintaining optimal “mechanical coupling” btw the right ventricle and pulmonary circulation to promote adequate left-sided filling and systemic perfusion
• interventions that may affect RV preload, inotropy, afterload, and oxygen supply/demand relationships
• Serious Consequences with these complexities:
  -transient HoTN
  -mechanical ventilation
  -modest hypercarbia
  -small bubbles in IV
  -T-burg position
  -Pneumoperitoneum
  -single-lung ventilation

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Question 24

What is the hallmark of PAH? what does this lead to?

Answer 24

a hallmark of PAH is increased RV afterload, leading to RV dilation, increased wall stress, and RV hypertrophy

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Question 25

• The interaction between the ____ and the ___ ___ is pulsatile and dynamic, involving the compliance and “stiffness” of large & small vessels
• This is relevant during __ __ that occur during surgeries which affect RV pulsatile load
• Ventilator management can have effects on _ _ through the addition of PEEP, hypoventilation, hypercarbia, acidosis, and atelectasis

Answer 25

• The interaction between the RV and the pulmonary circulation is pulsatile and dynamic, involving the compliance and “stiffness” of large & small vessels
• This is relevant during acute insults that occur during surgeries which affect RV pulsatile load
• Ventilator management can have effects on RV afterload through the addition of PEEP, hypoventilation, hypercarbia, acidosis, and atelectasis

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Question 26

Myocardial supply and demand:
* What do we worry about with the heart when someone has PH?
* is the RV pressure higher or lower than aortic root pressure under normal circumstances?

Answer 26

• The thinner-walled RV is subject to greater wall tension for the same degree of increase in end-diastolic volume, leading to increased RV myocardial oxygen demand
• RV intramyocardial pressure is lower than the aortic root pressure

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Question 27

• What does PAH cause in regards to RV pressure?

Answer 27

elevated RV pressure leads to increased coronary flow during diastole
* making the RV more vulnerable to systemic HoTN, worsening the 02 supply/demand mismatch and potentially causing myocardial ischemia

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Question 28

What causes the “lethal combination” and what is the “lethal combination”

Answer 28

• The cause: systemic hypotention, RV ischemia, high afterload
• Lethal combination is: RV dialation, insufficient LV filling, reduced stroke volume, and further systemic hypotension

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Question 29

Studies show a substantial increase in perioperative morbidity and mortality in pts with PH undergoing ___ & ___

Answer 29

Knee and Hip replacement

Question 30

Why might a laparoscopy have an effect on Pulm HTN patients?

Answer 30

The combination of pneumoperitoneum, head-down position, and increased inspiratory pressure affects RV pressures and afterload