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Primary Pulmonary Hypertension
when pulmonary hypertension is the problem
Secondary Pulmonary Hypertension
when pulmonary hypertension is caused by another condition
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 Introduction To Pulmonary Hypertension

Updated January 25, 2007   Primary Pulmonary hypertension (PPH) hits less than a thousand people a year in the USA. Secondary pulmonary hypertension affects many more. Pulmonary hypertension (PH) is a state of too-high pressure in the blood vessels inside your lungs. It can be caused by many things. PH is hard to diagnose because until it gets very bad, symptoms are vague and could be caused by almost anything. Here's what happens:

Pulmonary HypertensionInside your lungs are lots of tiny blood vessels called capillaries. The inside of each capillary is lined with a special kind of cell called endothelial cells. The outside of each capillary is covered with smooth muscle cells. The endothelial cells normally keep blood from leaking out of the blood vessel. The smooth muscle cells normally allow the vessel to expand or shrink, depending on how much blood is inside them.
 
In PH, some of the endothelial cells lining the capillaries weaken, and may enlarge. Since these cells line the inside of the capillaries, when they get bigger they make the inside of the blood vessel smaller - less room for blood to pass through. Blood may leak out as well.
   Also, the outer smooth muscle cells shrink. This muscle shrinkage tightens the blood vessels - like holding a sponge in your hand and squeezing, the muscle cells on the outside of the blood vessel squeeze, making the capillary smaller. This increases the pressure inside them.
 
The high pressure in these capillaries resists the heart's efforts to pump blood through them. When this happens in enough capillaries, the flow of blood between the heart and lungs is seriously reduced.

Your heart's right ventricle - which pushes blood through your lungs - overcomes this extra resistance by working harder. However, it can't keep this up forever. Eventually, the extra work the heart's right ventricle has to do permanently damages it. Heart failure results.
     When your symptoms get bad enough - usually after most of the damage to your heart is already done - a doctor will see that you have heart failure symptoms. He will probably test you for heart failure. That's why an echocardiogram is the test that usually spots pulmonary hypertension.

 The Basic Problems In Pulmonary Hypertension

Constricted Blood Vessels - There are several basic problems in pulmonary hypertension patients. Number one is vasoconstriction - the small blood vessels in your lungs constrict (get narrow, tighten up) and this makes it very hard for your heart to push blood through them.

Heart Failure - The heart's right side is working too hard to get blood through the constricted blood vessels in your lungs. Also, the lack of strong blood flow through your lungs reduces the amount of blood getting back to the left side of your heart. So you may develop left-sided heart failure as well.

Not Enough Oxygen - This lack of strong blood flow means a lack of oxygen as well, and this is called hypoxemia. This is why you may have to use an oxygen machine to breathe more easily.

Remodeling - There is also a change in the structure of your lungs' blood vessels - a process called remodeling. The cells on the inside of the small blood vessels weaken and deform, and the muscle cells on their outside over-react and tighten up. Not only does this narrow the opening that blood has to pass through, but these cells perform other functions that they can no longer do properly.

Blood Clots - Another problem is blood clots. People with PH may get chronic blood clots, which can further block small blood vessels in the lungs. All these things add up to an overworked heart and a real hard time breathing.

 Links To Other PH Resources Online
 Common Pulmonary Hypertension Symptoms
  1. shortness of breath (dyspnea)
  2. fatigue
  3. leg edema
  4. general weakness (asthenia)
  5. palpitations
  6. feeling of fullness in abdomen (from enlarged liver)
  7. chest pain (angina)
  8. coughing
  9. lightheadedness, dizziness
  10. fainting (syncope) or near-fainting (presyncope)
  11. bluish fingertips or lips
  12. nausea
  13. loss of appetite
  14. hoarse voice
 Causes of Pulmonary Hypertension
Primary Pulmonary Hypertension (PPH)
may be genetic or partly genetic - it often runs in families. It may be set off by a "trigger" that might be something like use of certain appetite suppressants, cocaine, meth (speed), inhaled solvents, contaminated oils such as rapeseed oil used for cooking, or L-tryptophan
Secondary Pulmonary Hypertension (PH)
has a lot of possible causes, including: chronic blood clots in the lungs, COPD, CHF, heart valve disease, physical heart-lung abnormalities like ventricular septal defect, toxic substances, cancer (tumors), AIDS, certain high blood pressure conditions, collagen disorders (like lupus, scleroderma, rheumatoid arthritis, and vasculitis), severe sleep apnea, emphysema, cystic fibrosis
     It is common to find more than one contributing factor, such as COPD, low oxygen levels in the blood (hypoxia), heart failure, being too fat, and sleep apnea
 Testing for pulmonary hypertension

Usually, an echo is the test that spots PH, because most people get diagnosed only after their PH has progressed a long way, causing heart failure symptoms to be apparent. Testing is done for several reasons:

  1. to diagnose PH
  2. to discover if some other health problem is causing your PH. If so, treating that underlying condition may improve your PH or prevent it from getting worse
  3. to hopefully discover what treatments may work best for you
Chest x-ray
may show enlargement of the right ventricle or or right atrium
EKG (electrocardiogram)
may point to PH
Echocardiogram
can estimate pulmonary artery pressure from studying your heart valves. In advanced pulmonary hypertension, RV size and function usually show up as abnormal. Heart wall motion may also be abnormal. However, echo only gives estimates. If it looks like PH on echo, a cath may be necessary
Complete Blood Count (CBC)
may spot chronic respiratory alkalosis (too-high pH levels) or low oxygen level in blood cells
Blood clotting tests
called PT and PTT tests, these measure how long it takes your blood to clot. This information helps decide what dose of blood thinner will prevent blood clots in your lungs
Liver function tests
cirhossis can cause pulmonary hypertension and PH can cause edema in your liver
HIV test
pulmonary hypertension can be a complication of AIDS
Autoimmune tests
an "antinuclear antibody" or "anticardiolipin antibody" test done on your blood can spot - or rule out - autoimmune disease like lupus (where your own body attacks itself, especially a part of blood vessel walls), chronic liver disease, scleroderma (disease affecting skin, organs and joints), or collagen vascular disease (where a tough glue-like internal protein interacts with bones, tendons and other connective tissue)
Arterial blood gas
blood is drawn from an artery instead of from a vein to check the amount of oxygen in your blood. Arteries are much deeper under the skin so this one can hurt
Lung function tests
a series of lung tests that may rule out other causes for your symptoms. If so, a cath may not be necessary
Thyroid function tests (called thyroid-stimulating hormone (TSH) screen)
many PH patients have thyroid problems
Sleep test to detect apnea
20% or more of PH patients have sleep apnea, which makes their PH worse
Ventilation/perfusion lung scan
can spot chronic blood clotting in the lungs, which can cause or worsen PH
6-minute walk test
a maximum exercise test like Vo2max may not generally be a good idea in PH patients
TEE (transesophageal echo)
possibly - gets better "pictures" than a regular echo
MUGA
possibly - maps heart functions accurately
MRI
possibly - can spot certain blood clotting problems
CT scan
possibly - may spot or rule out what is called interstitial lung disease or ILD. That name covers a whole group of lung diseases that cause PH-like symptoms
Right-heart cath (pulmonary cath)
with vasodilator challenge - see next section
Left-heart cath
possibly - if left heart function is in doubt or CAD is suspected
Lung biopsy
possibly - if a condition is suspected that would respond to steroids, such as fibrosis or vasculitis. This is done during right-heart cath
 The Right-Heart Cath

Once you are diagnosed with PH, you will almost certainly have a pulmonary cath. This is also called a right-heart cath or Swan-Ganz cath (the type of catheter used is actually named Swan-Ganz). The catheter is usually inserted through the right jugular vein in your neck. A tiny balloon is inflated at the end of the catheter. That lets it "float" along, carried by the flow of blood in your vein toward your pulmonary artery.
     The pulmonary artery is the main blood highway between your lungs and heart. It carries oxygen-poor blood from the right ventricle to the lungs. In the lungs, that blood picks up oxygen and travels to the left side of the heart, where it is pumped out to the rest of the body.

Pressures like those described in the last section are measured by cath. PCWP is measured when the balloon drifts into a blood vessel too small to let it pass through. The balloon blocks that vessel entirely so a branch of the pulmonary artery is "freeze-framed" or stopped in action, so to speak. Since the left atrium dumps its blood into the left ventricle, measuring its pressure shows whether the left ventricle can load up with blood properly.

Measuring all these pressures helps the doctor figure out how serious your PH really is, because PH is a state of too-high pressure in the lungs and heart. How high is very important for deciding what treatments to try. Blood flow to and from the heart will also be measured. Sometimes abnormal blood flow patterns point to a heart defect never before noticed. Surgery to repair such a defect might really help. Measuring heart function also lets the doctor know if you have - or are developing - left-heart failure that will need treatment. 

Acute Vasodilator Challenge

During your pulmonary cath, you will probably have an "acute vasodilator challenge." The doctor will give you strong but short-acting IV drugs to expand your arteries (vasodilate). If you respond well to one of these drugs - meaning that your arteries expand nicely - you can probably get some relief from your PH by taking calcium channel blocker pills every day. About one in four PH patients respond to oral drugs.
     Safer substances are used now than in the past for this "challenge," like inhaled nitric oxide or prostacyclin. I have not yet written a page just about the right-heart cath experience from a patient's point of view. However, you can get a good idea of the general procedure by reading my page about left-heart cath.

Possible Pulmonary Cath Risks 

Your chance of suffering one of these complications is very, very small. The more experienced your "operator" is - and his team - the better your chances of not having any of these effects. That's why you are better off at a medical center that hosts a lot of right-heart caths every year, and with a doctor (called an operator) who does a lot of them every year - and I mean hundreds every year. I have had a right-heart cath myself and had no problems with it or from it. The possible risks include:

 Treating pulmonary hypertension

Treatment depends partly on what caused your PH. Pulmonary hypertension caused by chronic blood clots will be treated differently than PH caused by sleep apnea, and so on. However, it's a matter of degree. Most of the same drugs will be used because they relieve symptoms.

Treating PH begins with trying to reverse or halt any conditions that are causing it or making it worse. PH linked to high hematocrit - too many red blood cells - may respond to "bloodletting." PH linked to sleep apnea may improve with CPAP use at night, and so on.

Some common sense things get overlooked by people with PH. You must lose weight if you are too heavy. Smoking and drinking are extremely bad ideas. A structured exercise program - designed by a pulmonology/cardiology rehab team may help your body use the oxygen that it does get more efficiently, improving your quality of life. A low sodium diet will reduce edema and make you breathe easier. Taking your meds as prescribed and making changes by working with your doctors instead of "tweaking" things on your own will lengthen and improve your life.

Diuretics
to relieve edema. Your doctor must monitor you carefully because symptoms that seem to mean dehydration may be from underfilling of the heart instead. Aldactone (spironolactone) may be effective when the liver swells with fluid, and can be used along with loop diuretics like Lasix (furosemide), Demadex (torsemide), or Bumex (bumetanide)
Low sodium diet
if you don't stick to a sodium restriction of 2000 mg a day max, your diuretics won't work and you will feel worse. Really
Digoxin (Lanoxin)
as in heart failure, digoxin (Lanoxin) can improve quality of life although it does not improve mortality
Calcium channel blockers
these drugs relax and expand your arteries (vasodilation), helping blood move better through your lungs. They may reduce the strength of your heart's beating though. Some people will benefit from them and some will not. Too-low blood pressure is one thing people with PH taking such drugs must watch for. That sounds weird since too-high lung pressures are the problem but system blood pressure and the pressure in your lungs' blood vessels can't get too far out of synch or you can have problems
Bosentan (Tracleer) made by Actelion
a pill, bostenan blocks the action of a hormone called endothelin. PH patients have too-high levels of endothelin, which is hard on the lungs. Bostenan use may lower endothelin levels and lower artery pressure. Liver damage may occur in about 11% of patients so regular liver testing is important. Get the full prescribing information here
Sidenafil Citrate (Revatio) made by Pfizer
The FDA approved the main ingredient in Viagra (sildenafil citrate) June 7, 2005 under the name Revatio. It dilates (relaxes) blood vessels and improves exercise ability in PH patients. The approved dose for PH is 20mg three times a day - different than in Viagra pills. Just like Viagra, people taking nitrates (like nitroglycerin or Isordil [isosorbide dinitrate] ) should avoid Revatio. Taking both can cause fatal blood pressure changes.
Sitaxsentan (Thelin) by Encysive Pharmaceuticals
blocks endothelin-1 at the ETA receptor. Positive phase 2A study results were presented in November of 2000 at the AHA meeting. That trial showed improved exercise capacity. A Phase 3 trial is in progress - see the links section on this page.
Epoprostenol (Flolan) made by GlaxoSmithKline
a prostacyclin, Flolan directly vasodilates (expands, relaxes) blood vessels. Flolan also prevents blood cells from clumping together. It increases cardiac output and lowers afterload, improving PH symptoms, and it also improves survival time. This prostacyclin is similar to the natural prostacyclin produced by the cells lining our blood vessels.
     Flolan is an IV drug which is only active in your blood for about 5 minutes, so you have to take it as a continuous IV infusion 24 hours a day. The delivery system is complex and requires you to learn sterile preparation, operation of the pump, and care of the IV catheter. It ain't cheap, costing anywhere from 25,000 dollars US a year on up. Flolan must be kept cold after mixing but cannot be frozen. See the full prescribing information here
Iloprost (Ventavix) made by CoTherix
a more stable prostacyclin at room temperature, Iloprost can be inhaled. It acts directly on the lungs, hopefully reducing side effects through the rest of the body. Iloprost has a half-life of 20 minutes or more.
Remodulin (UT-15 or treprostinil sodium) made by United Therapeutics
a synthetic prostacyclin. It was approved in July of 2002. It is a strong vasodilator and slows scarring and cell growth inside the lungs' blood vessels. It increases cardiac output and improves exercise ability. The drug's action lasts from 4 to 6 hours instead of the 2 to 6 minute action of Flolan, and Remodulin is stable at room temperature for up to 5 years.
     Remodulin is injected under the skin instead of through an IV catheter. This under-the-skin delivery works with a pager-sized infusion pump. This reduces infection risk because there is no "indwelling" catheter. Remodulin does not require mixing - it comes ready to use in glass vials. Every 3 days, the injection site is changed (usually in the stomach area). The chief drawback to Remodulin is pain at the injection site, which can be severe
Blood thinners like warfarin (Coumadin)
help prevent blood clots from forming - a chronic problem with PH
Oxygen
to aid breathing and keep oxygen level in the arteries up. Keeping an oxygen "saturation" of at least 90% in your arteries by using an oxygen machine may help a lot
Surgery
some patients with chronic blood clotting in their lungs' blood vessels may be helped by surgery. The most experienced team doing this kind of surgery is located at San Diego, California, USA. The surgery is called "pulmonary thromboendarterectomy." It can restore some patients to near-normal functioning, but mortality is about 10% except at San Diego, where it is about 5%. About 90% of survivors improve to class one or class 2 after recovery. See this page for more.
     Patients who may benefit from this surgery have PH caused by - or seriously complicated by - large chronic multiple blood clots forming in the lungs' blood vessels. This is called CTEPH or "chronic thromboembolic pulmonary hypertension." Candidates usually are class 3 or class 4, with exercise capacity less than 6 METS and PVR of 3 Wood's units or higher. Patients require lifelong blood thinners afterward
Inhaled Treprostinil Helps PH
 

October 18, 2006 - Researchers studied inhaled treprostinil for severe PH by measuring its effects on blood flow and gas exchange in the lungs. Although inhaled iloprost helps PH patiens, it requires 6 to 9 inhaling sessions per day. Treprostinil lasts longer in the body when inhaled.
     Three different studies were done including 123 patients using right heart cath. The main endpoint was change in PVR. Average lung artery pressure was about 50 mmHg in all three studies.

Randomized crossover study of 44 patients
Treprostinil and iloprost at an inhaled dose of 7.5 mug lowered PVR but treprostinil's effect lasted longer with less side effects.
Dose raising study of 31 patients,
Effects from inhaling the drug were studied for 3 hours. An almost maximum immediate PVR improvement was seen at 30 mug treprostinil.
Reducing inhaling time study while using the same dose in 48 patients.
Treprostinil was inhaled at higher and higher doses with a pulsed ultrasonic nebulizer, sort of like a measured dose inhaler. Fifteen mug treprostinil was inhaled with 18, 9, 3, 2 pulses or just one pulse. Each amount caused sustained blood flow improvement in the lungs with no major side effects.
     Inhaled treprostinil improves and maintains better blood flow in the lungs. The drug is well tolerated at low doses and only takes a few breaths to inhale during each session.

Researchers also studied inhaling treprostinil in PH patients already taking oral bosentan. Twelve PH patients with symptoms despite taking bosentan got either 30 microgams of inhaled treprostinil 4 times a day (6 patients) or 45 micrograms 4 times a day (6 patients), again using an ultrasonic nebulizer.
     Six-minute walk distance, heart class, and blood flow were measured at study start and again at 12 weeks. One patient dropped out due to another health problem. In the other 11 patients, inhaled treprostinil was safe and well tolerated.
     Inhaled treprostinil increased 6-minute walk distance from 339 meters to 406 meters at 12 weeks. Only one patient taking 30 micrograms improved walk distance but 5 of 6 patients taking 45 micrograms improved. Over 12 weeks, average pulmonary artery pressure improved 10% and pulmonary vascular resistance improved 26%. Heart class improved from class 3 to class two in 9 of 11 patients.
     Inhaled treprostinil seems safe and effective for improving exercise ability, heart class, and lung function in PH patiens with symptoms already taking bosentan.
 
Source: J Am Coll Cardiol. 2006 Oct 17;48(8):1672-81. Epub 2006 Sep 26.
Title: Favorable effects of inhaled treprostinil in severe pulmonary hypertension: results from randomized controlled pilot studies.
Authors: Voswinckel R, Enke B, Reichenberger F, Kohstall M, Kreckel A, Krick S, Gall H, Gessler T, Schmehl T, Ghofrani HA, Schermuly RT, Grimminger F, Rubin LJ, Seeger W, Olschewski H.
PMID: 17045906.
Source: J Am Coll Cardiol. 2006 Oct 3;48(7):1433-7. Epub 2006 Sep 14.
Title: Safety and efficacy of inhaled treprostinil as add-on therapy to bosentan in pulmonary arterial hypertension.
Authors: Channick RN, Olschewski H, Seeger W, Staub T, Voswinckel R, Rubin LJ.
PMID: 17010807

 Things To Avoid

Things to avoid when you have pulmonary hypertension include pregnancy, high altitude, decongestants, beta-blockers, and NSAIDS

 Abbreviations and Acronyms Explained

This next stuff seems awfully technical, I know, but if you understand this section, you really have a grip on pulmonary hypertension. If it's too much, just read the first sentence of each one and skip the formulas used to calculate the values.
     Please note: I researched about 10 sources for most of these number values. However, the values given by (and for) doctors vary so much that I decided to use an average for each range. The Merck Manual even disagrees with itself about the range of normal values for some of these from one page to another! See this page for more on uncertainty in measurement.

CO
Cardiac Output - the volume of blood ejected by the heart per minute
Formula: CO (in liters/minute) = heart rate (in beats/minute) times stroke volume (in liters/beat)
Normal range = 4 to 8 liters per minute
CVP
Central Venous Pressure - the pressure in the large vein just outside the heart's right atrium. CVCP is the same as RAP (right atrial pressure)
Directly monitored during pulmonary cath
Normal range = 1 to 7 mmHg
DPAP
Diastolic Pulmonary Artery Pressure - the pressure as blood moves from the pulmonary artery to the lung's capillaries.
Directly monitored during pulmonary cath
Normal range = 6 to 13 mmHg
LAP
Left Atrial Pressure - pressure in the upper left heart chamber. Same as PCWP
Directly monitored during pulmonary cath
Normal range = 2 to 12 mmHg
LV
Left Ventricle - the lower left heart chamber. It pumps blood out into, and throughout the body
LVEDP
Left Ventricular End-Diastolic Pressure - pressure in the LV when it is full of blood, just before it starts squeezing to pump blood out into the body
Directly monitored during pulmonary cath
Normal range = 5 to 12 mmHg
LVESP
Left Ventricular End-Systolic Pressure - pressure in the LV after it has pumped blood out into the body but before it starts filling with blood for the next beat
Directly monitored during pulmonary cath
Normal range = 90 to 140 mmHg
mmHg (also called "torr")
millimeters of mercury - how high pressure pushes a column of mercury in a glass tube. It's how regular blood pressure readings are measured: 120/80, etc,... In the SI (metric) system, one mmHg = 133.322 Pascals (Pa)
MPAP (also called MAP)
Mean (average) Pulmonary Artery Pressure - average pressure in the pulmonary artery. In the formula, diastole (heart's relaxation phase) counts twice as much as systole (heart's contraction phase) because 2/3 of the heart's cycle is spent in diastole
Formula: [(2 times DPAP) plus SPAP] divided by 3
Normal range = 10 to 16 mmHg
PAOP
Pulmonary Artery Occlusion Pressure - same as PCWP
PAP
same as MPAP
PAWP
Pulmonary Artery Wedge Pressure - same as PCWP
PCWP (also called PAWP and PAOP)
Pulmonary Capillary Wedge Pressure - an indirect measurement of pressure in the heart's left atrium.
Directly monitored during pulmonary cath
Normal range = 5 to 13 mmHg
PFT
Pulmonary Function Tests - tests to see how well your lungs work
PH
Pulmonary Hypertension - state of high pressure in your lungs' blood vessels. An average pulmonary artery pressure (MPAP) higher than 25 mmHg at rest or a PVR higher than 3 Wood's units is considered PH. An MPAP of 26 to 35 mmHg is considered mild PH; 36 to 45 mmHg moderate PH; and over 45 mmHg severe
Pulmonary
pertaining to the lungs
PVR (in Wood's Units)
Pulmonary Vascular Resistance - the general pressure against which the RV must pump to push blood through the lungs
Formula: PVR = (MPAP minus PCWP) divided by CO. The result is said to be in Wood's units
Normal range = 0.7 to 1.1 Wood's Units
PVR (in dynes/second/centimeter 2)
Pulmonary Vascular Resistance - the general pressure against which the RV must pump to push blood through the lungs
Formula: PVR = [(MPAP minus PCWP) divided by CO] times 79.9
Normal range = 90 to 250 dynes/second/centimeter 2
RAP
Right Atrial Pressure - same as CVP
Directly monitored during pulmonary cath
Normal range = 2 to 7 mmHg
respiratory
pertaining to breathing
RV
Right Ventricle - the lower right heart chamber that pumps blood to the lungs. It is weaker, smaller, and shaped differently than the heart's LV
RVDP
Right Ventricular Diastolic Pressure - pressure inside the RV when it is full of blood but has not started to pump it into the lungs
Directly monitored during pulmonary cath
Normal range = 0 to 8 mmHg
RVSP
Right Ventricular Systolic Pressure - pressure inside the RV when it has just pumped blood into the lungs but has not started to refill with blood
Directly monitored during pulmonary cath
Normal range = 15 to 28 mmHg
SPAP
Systolic Pulmonary Artery Pressure - pressure in the pulmonary artery when the RV pushes blood through it into the lungs
Directly monitored during pulmonary cath
Normal range = 17 to 28 mmHg
SV
Stroke Volume - the amount of blood ejected from the heart with each beat
Formula: SV = end-diastolic volume minus end-systolic volume
Normal range = 50 to 80 milliliters/beat
SVR
Systemic Vascular Resistance - the resistance against which the LV must pump
Formula: SVR = [(MPAP minus RAP) divided by CO] times 80
Normal range = 800 to 1200 dynes/second/cm2
Wood's Units
unit of measure for PVR. One Wood's Unit equals the PVR of an average healthy person. That is:
MPAP = 13 mmHg
LAP = 8 mmHg
CO = 5 liters per minute
so average healthy PVR = (13 minus 8) divided by 5, which equals one Wood's Unit

All information on this site is opinion only. All concepts, explanations, trials, and studies have been re-written in plain English and may contain errors. I am not a doctor. Use the reference information at the end of each article to search MedLine for more complete and accurate information. All original copyrights apply. No information on this page should be used by any person to affect their medical, legal, educational, social, or psychological treatment in any way. I am not a doctor. This web site and all its pages, graphics, and content copyright © 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007 Jon C.

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