#80: Pulmonary Hypertension, freeways, and cows in heart failure

January 29, 2018 | By Matthew Watto, MD

Pulmonary hypertension deconstructed with clinical pearls from cardiologist, John J. Ryan MD, FACC, FAHA, Director of University of Utah Pulmonary Hypertension Center. We discuss classification, diagnosis/differentiation, initial workup, additional testing, echo findings, how to counsel patients with pulmonary hypertension, and why cows never get ankle edema!

Written and produced by: Jordana Kozupsky, NP and Matthew Watto, MD

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Case from Kashlak Memorial:
I was in clinical seeing Mrs. R, one of my favorites. She’s a lovely 75 yo Hispanic female with obesity, BMI 32, diabetes, hypertension, hyperlipidemia, atrial fibrillation (on coumadin), and sleep apnea with poor compliance to CPAP who presents with dyspnea and fatigue. She thinks she might have asthma. She has no cough, wheezing or h/o asthma/reactive airways disease. Vitals signs show resting oxygen sats are 92% on room air. Blood pressure is 138/84, sorry 2017 ACC/AHA guidelines. You suspect pulmonary hypertension (PH) since that’s the topic of this episode.

Self Assessment Questions

Goal: Listeners will gain a better understanding of the etiology, diagnosis & treatment of pulmonary hypertension.

Learning objectives:
After listening to this episode listeners will…

1. Learn an easy to understand analogy to explain pulmonary hypertension (PH) to patients
2. Classify PH into its subtypes
3. Learn a practical approach to the diagnosis and workup of PH
4. Recommend appropriate treatment options for most patients with PH
5. Initiate the initial diagnostic workup for suspected PAH
6. Gain an understanding of echo findings relevant to PAH
7. Gain confidence in distinguishing PH vs heart failure with preserved ejection fraction (HFpEF)

Clinical Pearls:

1. Pulmonary hypertension (PH) is like a detectable troponin; you must always consider it abnormal and search for an underlying cause.
2. Ninety percent of PH is due to left heart disease (60%), chronic hypoxic lung disease (20%), or a combination of the two (10%). You must aggressively treat underlying disease and modifiable risk factors.
3. Don’t miss chronic thromboembolic pulmonary hypertension (CTEPH)! It’s the ONLY curable cause of PH (via pulmonary endarterectomy). V/Q (ventilation/perfusion) scans are tough to administer & read. Refer to a specialized center if concerned about CTEPH and allow them to perform V/Q scan.
4. Pulmonary arterial hypertension (PAH) specific therapies do not cause systemic vasodilation or postural hypotension. Don’t stop PAH-specific therapy, even if blood pressure (BP) is low!! Stopping therapy causes systemic hypotension through increased pulmonary artery pressure (PAP), decreased cardiac output (CO), decreased stroke volume, and a resulting fall in BP.
5. Do not use PAH-specific therapies (sildenafil, bosentan, etc.) in PH groups other than Group 1, PAH. These therapies may increase V/Q mismatching and worsen outcomes. The best pulmonary vasodilatory is supplemental oxygen, which should only vasodilate areas being ventilated!
6. Prognosis: Life expectancy is 3-5 years w/o treatment. Death is due to right heart failure. Worst prognosis is chronic hypoxic lung disease (group 3) (Gall H, et al. J Heart Lung Transplant. 2017).

Patient Education

1. Freeway analogy for PH: Blood vessels in lungs should be like a four-lane road. Blood moves through at high speeds. In PH, the freeway goes from four lanes to one lane due to thickened and narrowed blood vessels. Now there is just one lane open so during exertion blood flow through the lungs cannot meet the body’s oxygen requirements. Signs and symptoms may include: hypoxia, chest pain, syncope, and heart failure.

Definitions and Classification

1. Definition pulmonary hypertension (PH) = mean pulmonary artery pressure (PAP) ≥ 25 or pulmonary vascular resistance (PVR) > 3 Wood units.
2. Definition pulmonary arterial hypertension (PAH) = mean pulmonary artery pressure (PAP) ≥ 25 AND pulmonary capillary wedge pressure (PCWP) ≤15 and pulmonary vascular resistance (PVR) > 3 Wood units.
3. Classification (see Table 1)
   
4. Normal mean PAP is 15 mmHg. Anything above 18 mmHg is associated w/mortality. A PAP under 25 mmHg doesn’t mean there is nothing going on! Look for an underlying cause.
5. Epidemiology of PH: 90% is due to left heart disease (LHD), chronic hypoxic lung disease, or a combo of the two. The last 10% is due to pulmonary vascular diseases: PAH, CTEPH or rare/miscellaneous causes (i.e. group 5). Breakdown among the 90% is as follows (Strange G et al. Heart. 2012)
   1. 60%- LHD (systolic/diastolic dysfunction, valvular heart disease, congenital)
   2. 20%- chronic hypoxic lung disease (COPD, emphysema, pulmonary fibrosis, sleep-disorder breathing, & obesity hypoventilation syndrome)
   3. 10%- combo of LHD & chronic hypoxic lung disease

Diagnosis

1. Questions to ask: Can you walk as far as you want? How far can you walk? Can you walk “on the flats” without shortness of breath? When were you last 100%? Have you had syncope? Angina? *Presence of syncope or angina indicate a poor prognosis.
2. Initial Workup (2015 European Guidelines): Echo, 6-Minute walk test, NYHA functional class, EKG, pulmonary function testing (PFTs) including spirometry & DLCO, chest xray, overnight oximetry, and arterial blood gas (room air) if concern for obesity hypoventilation syndrome. Hi-res CT chest can be considered in select patients.
3. Echocardiogram: Measures right ventricular systolic pressure (RVSP), which is an estimate of pulmonary artery systolic pressure (PASP). Accurate to within 10-15 mmHg. Normal RVSP = 20-24 mmHg. An elevated RVSP = >35 mmHg [correlates with a PA diastolic pressure of 10-15 & mean PAP of ~25 mmHg]
4. Echo findings in LHD: Presence of L atrial enlargement, L ventricular hypertrophy provide 94% confidence that PH is from left heart disease (Thenappan T et al. Circ Heart Fail 2011).
5. Differentiating types of PH: “Look at the company it keeps” (e.g. A patient w/obesity, HTN, CAD, and diabetes more likely to have LHD; If lupus or scleroderma present then more likely PAH). Combine the history, exam, and echo findings to accurately predict etiology.  (see table 2 for PAH vs. heart failure with preserved ejection fraction [HFpEF])
   
6. CTEPH suspected?: Check *V/Q scan (+/- CT pulmonary angiogram). *Dr Ryan suggests this be done at a center specializing in PH.
7. PAH risk factors: HIV, schistosomiasis, congenital heart disease, portopulmonary HTN, connective tissue disease (lupus, scleroderma, mixed CTD), drugs/toxins (listed in #10), heritable (source 2015 ESC/ERS g/l)
8. PAH suspected?: Check HIV; hepatitis; schistosomiasis serology (returning travelers); connective tissue disease (CTD) panel, see below; screen for drugs/toxins (see list below); hereditary conditions
9. CTD panel: Antinuclear antibodies: anti-centromere, dsDNA, anti-Ro, U3-RNP, B23, Th/To and U1-RNP. Tests lupus, scleroderma, and mixed connective tissue disease.
10. Drugs-Toxins implicated in PAH: Definite– fenfluramine, SSRIs (maternal use affecting newborn); Likely– amphetamine, methamphetamine; Possible– cocaine, St John’s Wort, interferon, certain alkylating chemotherapeutic agents (e.g. cyclophosphamide)

Treatment

1. PH from chronic heart and lung disease (groups 2, 3): TREAT UNDERLYING CAUSE! Modify risk factors. Encourage weight loss. Ensure compliance with CPAP. Ask about chronic angina, and if present refer for cardiac rehab. Trial diuretics. Treat hypertension.
2. Diuretic therapy: Dr Ryan finds combination of loop diuretic (e.g. furosemide) and potassium sparing diuretic (e.g. spironolactone, amiloride) are effective and well tolerated to control hypertension and optimal volume status. Utilize ACE inhibitor if further BP control needed.
3. Follow up after Tx initiated: At 12 weeks consider repeating echo, NYHA functional class assessment, 6-Minute walk test. Consider a right heart cath (RHC) if not improving.
4. When to refer: Syncope; NYHA functional class III or IV; atypical presentation; workup fails to identify a cause; patient w/PAH risk factors (see #14); congenital heart disease; suspicion of CTEPH; You feel confused or uncomfortable : )

Time Stamps:

• 00:00 Disclaimer
• 01:30 Introducing our new Correspondent Jordy
• 03:05 Listener feedback
• 04:40 Guest bio
• 06:25 Getting to know Dr Ryan
• 09:33 Picks of the week
• 15:20 Clinical case
• 16:35 How to explain pulmonary hypertension to a patient
• 18:12 Groupings of pulmonary HTN
• 21:20 Taking a history. Ask these questions.
• 23:30 Physical exam
• 25:45 Initial testing
• 27:40 Overnight pulse oximetry
• 29:00 Echo findings in pulmonary HTN
• 31:30 Transpulmonary gradient
• 33:33 What is a normal pulmonary artery pressure
• 35:15 Accuracy of PA pressure estimate by echo
• 39:04 Mechanism of shortness of breath in PH
• 40:10 Should you hold PAH meds in a hypotensive patient?
• 41:55 Therapy for PH and follow up
• 46:28 Who to refer
• 47:40 PAH risk factors
• 52:09 Mortality in PH
• 58:22 Take Home Points
• 60:24 Outro

Disclosures: Dr. Ryan reports no relevant financial disclosures. The Curbsiders report no relevant financial disclosures.

Links from the show:

1. Whistling Vivaldi (book) by Claude M. Steele
2. Mindset (book) by Carol Dweck
3. Sick Boy Podcast
4. Jean Claude Van Johnson (TV show) on Amazon
5. DynaMed Plus on Pulmonary hypertension classification and treatment (Subscription required)
6. Right ventricular hypertrophy on ECG https://lifeinthefastlane.com/ecg-library/basics/right-ventricular-hypertrophy/ -Free
7. Right ventricular strain patter on ECG https://lifeinthefastlane.com/ecg-library/right-ventricular-strain/ -Free
8. 2015 ESC/ESR Guidelines for Diagnosis & Treatment of Pulmonary HTN–
9. TOPCAT trial: Spironolactone for Heart Failure with Preserved Ejection Fraction