PH (Murray and Nadel) Flashcards
Definition of vasodilator responsiveness (vasoreactivity)
Based on 2009 ACC/AHA and 2015 ESC/ERS guidelines:
At least 10mmHg drop in mPAP AND mPAP less than 40mmHg in response to vasodilator during RHC
Caveats:
- stable or improved cardiac output
- normal oxygenation prior to starting test (so PVR is not a response to improved oxygenation)
When to not do vasodilator testing in RHC
- High risk of pulmonary venous HTN (CHF, elevated PCWP, PVOD) given risk of flash pulmonary edema
- Baseline bradycardia: avoid IV adenosine
3 meds (with dosing and duration) used for vasodilator test
- Inhaled nitric oxide: 20 or 40 ppm for 5 mins (or until positive response)
- IV epoprostenol 2-12 ng/kg/min every 15 mins
- IV adenosine 50-250 mcg/kg/min q2 mins
Meds for vasoreactive PH
CCBs: nifedipine XL or diltiazem
Dihydropyridine (vascular-selective): Nifedipine
-backup amlodipine
Non-dihydropyridine (myocyte-selective): Diltiazem
-avoid verapamil b/c too much negative inotropy
How common is vasoreactivity?
About 10-20% PAH pts who undergo testing have positive vasoreactive response
Only 1/2 who are vasoreactive clinically repsond to CCB
Explain change in PH definition (PASP cutoff) for 6th world symposium on PAH
mPAP cutoff dropped from 25 to 20mmHg because 14 normal (SD 3) so 2 SD above normal is 20ish, felt we’re potentially missing some mild PH cases (which do matter clinically b/c have higher mortality)
Differentiate numerical cutoffs for pre and isolated post-capillary PH
mPAP, PCWP, PVR
Pre-capillary PH: mPAP over 20, PCWP under 15, PVR at or above 3
Pure post-capillary PH: Mpap over 20, PCWP over 14 with PVR below 3
Differentiate numeric cutoffs for isolated postcapillary vs. combined pre/post capillary PH
mPAP, PCWP, PVR
Isolated postcapillary PH (group II): mPAP over 20, wedge over 15, PVR under 3
vs.
Combined pre/post capillary PH (group II and IV): mPAP above 20, PCWP above 15 but PVR above 3
Which WHO group involves
(a) Precapillary PH
(b) Isolated post-capillary PH
(c) Combined pre and post-capillary PH
WHO group for classifying PH
(a) Pre-capillary: I, III, IV, and some V
(b) Isolated post-capillary = groups II and V
(c) Combined- groups II and V
2 most common causes of group I PAH
Group 1 PAH (true PAH)
50% idiopathic PAH
25% connective-tissue disease associated PAH
Other causes of group IV PH aside from CTEPH
Group IV- anything that clogs pulmonary arteries
So can be clot = CTEPH
Also tumor (PA sarcoma, angiosarcoma, mets), vasculitis, congenital pulmonary artery stenosis
Name some etiologies of group V PH
Group V = multifactorial or not well understood etiology
-hematologic disorders: chronic hemolytic anemia, myelodysplasia
-metabolic disease: glycogen storage (Gauchers), sarcoid, PLCH (pulmonary langerhan cell histiocytosis)
PH vs. PAH
PH just means PA pressure above 20, while PAH is from actual pulmonary arterial remodeling/issue
PAH = group I PH
So most of workup for PH is to rule out L. heart disease, other lung disease, CTEPH basically to see if you have PAH (group I)
For which connective tissue diseases are PH screening recommended?
(a) How to screen
PH screening recommend for systemic sclerosis patients, based on DETECT study (2014) that has algorithm given high risk of pts with systemic sclerosis
Also MCTD (mixed connective tissue disease- on systemic sclerosis spectrum with some SLE, RA, and polymyositis
(a) systemic sclerosis, MCTD (sclerosis spectrum disorder) get screening PFT and TTE at start then annually, or with any symptom change
What is MCTD?
(a) Defining antibody
Mixed connective tissue disease = mixed features of systemic sclerosis, SLE, RA, and polymyositis
(a) Defining anti-U1-RNP (antinuclear ribonuclearprotein)
Drugs with definite association with PAH
Drugs/toxins associated with PAH
- Anorexigens- aminorex, fenfluramine, dexfenlfuramine (fenfen)
- methamphetamines
- dasatinib (TKI used for Philadelphia chromosome + ALL and AML)
Describe TR murmur
TR murmur = pansystolic at L sternal border
Why is nocturnal oximetry part of guidelines for PH diagnostic workup?
B/c of high association btwn OSA and PH, allllso because treating the OSA can improve cardiopulmonary outcomes
Differentiate significance of interventricular septal flattening in systole vs. diastole
interventricular septum flattening
in systole = RV pressure overload
in diastole = RV volume overload
Clinically/treatment wise not much difference…
EKG signs of RV hypertrophy
(a) RV thickness on TTE cutoff for hypertrophy
(a) RV thickness more than 4mm = hypertrophy on TTE
On EKG: see large R-wave in V1 (R:S more than 1) and large S-wave in V5/6 (R:S less than 1)
Formula for PVR
V = IR, so R = V(voltage) / I (current)
PVR (pulmonary vascular resistance) = delta P (mPAP - PCWP) / CO (cardiac output)
change in pressure/flow
Serious events associated with RHC
RHC adverse events
Access- hematoma
Catheter advancement- SVT
Vasoreactivity- hypotension
obv the feared and dreaded PA perforation