Pulmonary Hypertension: Classification: Class 1 & 2

00:01 Now, this is what I was referring to earlier with the WHO classification of pulmonary hypertension.

00:07 I'm gonna give you a brief description for every single class that you absolutely must know because the way that you approach these clinical vignettes, I'll show you, will be class by class by class by class. Begin with Class I.

00:23 Now, we will begin in chronological order by Class I.

00:26 Clinically, however, you'll begin this a little bit different.

00:30 Why? Keep it in mind, if it's familial, very difficult to sometimes figure this out immediately, isn't it? So it's easier to actually perform certain tests that are a lot faster to rule things out, Class II, III, and IV, so then, you would highly suspect Class I. Let's put it that way.

00:52 Once more, this is familial. What does that mean to you? Once upon a time, known as your primary pulmonary hypertension, get away from that.

01:00 Idiopathic pulmonary arterial hypertension is a much better descriptive name, majority of these will be familial.

01:10 Okay, that means that there's no secondary effect.

01:13 There's no hypoxia, in which there's pulmonary vasoconstriction.

01:18 There's no heart disease causing pulmonary arterial hypertension.

01:22 And there is no thromboembolic episode chronically resulting in increased pulmonary hypertension. Right? It's a familial. So, it's actually faster and more effective to rule out and we'll go through each one, II, III, and IV, and then to see as to whether or not Type I, in fact, is your proper diagnosis.

01:43 Now, what do you wanna know about familial? Well, it's an inactivation mutation of a particular gene called your bone morphogenic protein-receptor-2.

01:53 Note the entire name. I'm sorry, you must.

01:57 The abbreviation is BMPR2 or it's receptor, BMP is bone morphogenic protein.

02:04 What does it do? It normally inhibits the vascular smooth muscle proliferation and so, therefore, if you have such a mutation, when you inactivate the gene which normally controls the proliferation, uh-oh, where am I? Blood vessel.

02:21 And so, therefore, if you move this suppressor, you have increased proliferation, end up having pulmonary arterial hypertension. Prognosis, poor.

02:31 Would you remind me as to what the normal pressure should be within your pulmonary artery? The mean, mean pulmonary arterial pressure. 15 mmHg, correct? 15 mmHg.

02:45 Technically, the systolic is approximately 25 mmHg and then the diastolic is approximately, let's say, 8-10 mmHg, but the mean is 15 mmHg.

02:53 What if you found that the pulmonary pressure is at 25 and greater millimeters mercury? Now, we have pulmonary hypertension. I'm gonna be very clear about how to approach this.

03:06 Class I, under our WHO classification, is now technically called pulmonary arterial hypertension.

03:17 I repeat, pulmonary arterial hypertension.

03:20 You can no longer call this pulmonary hypertension.

03:23 Idiopathic could be a cause under familial.

03:29 You can have a very important protein and a mutation that takes place inactivated.

03:34 The name of that protein is bone morphogenic protein-receptor-2 which normally inhibits the vascular smooth muscle proliferation.

03:42 And if this is the cause of the pulmonary arterial hypertension, the prognosis is quite poor.

03:46 Other important causes of pulmonary arterial hypertension: drugs, amphetamine, cocaine, systemic diseases such as connective tissue disease for example, scleroderma, infections, rarely but could occur.

04:04 HIV has shown to cause Class I pulmonary arterial hypertension or maybe a patient is suffering from schistosomiasis.

04:14 Portal hypertension could be a cause.

04:16 Technically, that is then called portal pulmonary hypertension.

04:20 And congenital heart disease receptor defects.

04:22 As you can see here, under Class I, it is called pulmonary arterial hypertension.

04:27 There are multiple causes here.

04:30 Class II, is then referred to as being pulmonary hypertension.

04:37 Class II pulmonary hypertension is then caused by, well, let me ask you.

04:43 Which side of the heart would have to then dysfunction so that you would have backup and congestion in your pulmonary blood vessels? You better say left ventricle, right? So, left-ventricular failure may result in Class II pulmonary hypertension.

04:59 How many ventricles do you have? Two. Welcome to Class II.

05:05 Now, onto Class II, please.

05:09 Now, Class II, the way that I've thought about this in the way that maybe might help you, Class II is a--is there any way that you could possibly think of your heart having two sides? Would that perhaps help you? Okay. The reason I say that is, Type II or Class II, excuse me, type of pulmonary hypertension is going to be trouble in your pulmonary blood vessels secondary to the heart or secondary to the heart, are we clear? So, pay attention to that and so, if it helps you to think of the heart as having two sides, and if you have--let's say that you have right ventricular hypertrophy and you have to start on the left side.

05:46 So if you have left-sided heart failure, then you might back up into pulmonary veins, right? You further back up into pulmonary capillary, pulmonary artery.

05:55 So therefore, here, the pulmonary hypertension was due to a left-ventricular heart disease.

06:00 That's Class II. How would you rule this out? Maybe something as simple as E and E.

06:08 What are these? Echocardiogram, EKG, already?