1. Evaluation of Dyspnea

2. Variable Definitions Of Dyspnea
Unpleasant or uncomfortable respiratory sensations
Difficult, labored, uncomfortable breathing
Awareness of respiratory distress
The sensation of feeling breathless or air hunger
An uncomfortable sensation of breathing
ATS guidelines: subjective experience of breathing discomfort that consists of qualitatively distinct sensations that vary in intensity
ATS. AJRCCM, 1999.

3. Variation In Symptoms of Dyspnea by Condition
Manning. NEJM, 1995.

4. Respiratory Control Systems
Designed to maintain gas exchange equilibrium and acid base status
Abnormalities in this system -> dyspnea-> severe patient distress

5. Mechanisms Of Dyspnea: Respiratory Center Output
Chemoreceptors
Peripheral: carotid bodies, aortic arch
Sense changes in PO2, acidosis, hypercapnea
Central: medulla
pH and PCO2 changes
Hypercapnea
Potent stimulus of dyspnea
Hypoxia
Less potent stimulus than hypercapnea
Manning. NEJM, 1995.

6. Mechanisms Of Dyspnea: Stimulation Of Mechanoreceptors
Upper airway
Pulmonary receptors
Limitations of movement exacerbate dyspnea
The sensation of dyspnea varies with activation
Chest wall receptors
Restricted motion exacerbates dyspnea
Redundant to pulmonary receptors
Nausherwan. Chest, 2010.

7. Other Mechanisms Of Dyspnea
Mechanical loading
Changes in airway resistance, pulmonary or chest wall compliance
Neuromechanical dissociation
Air flow not equal to expected results of brain output
Impaired oxygen utilization or delivery
Anemia
Increased CO -> EDP-> pulmonary edema
Localized acidosis or resp muscle fatigue
Deconditioning
Poor cardiac and peripheral efficiency, early anaerobic metabolism and acidosis

8. Structural Approach Respiratory Cardiac
Controller: depth and rate of breathing
Ventillatory pump: movement of gas in and out of the alveolous
Gas exchanger: pulmonary vasculature, alveoli
Cardiac
Anemia
Deconditioning
Heart failure

9. Most Common Causes of Dyspnea
Asthma
COPD
ILD
Cardiac disease

10. Differential Diagnosis of Dyspnea
Cardiac
Heart failure
Coronary artery disease
Arrhythmia
Pericardial disease
Valvular heart disease
Pulmonary hypertension

11. Diagnosis of Dyspnea Pulmonary Chronis obstructive pulmonary disease
Asthma
Interstitial lung disease
Pleural effusion
Malignancy
Bronchiectasis

12. Diagnosis of Dyspnea Non-cardiac/Non-pulmonary Thromboembolic disease
Psychogenic
Deconditioning
Obesity
Anemia
GERD
Metabolic conditions
Cirrhosis
Thyroid disease
Neuromuscular
Chest wall
Upper airway

13. Approach To The Patient
History and physical
EKG
Echocardiogram
CXR/CT scan
Spirometry
Cardiopulmonary exercise testing

14. Differentiating Heart vs Lung Etiology
1586 patients presenting with dyspnea
No clear heart failure
Maisel. NEJM, 2002.

15. BNP Is Useful to Differentiate Heart Failure From Other Dyspnea
Maisel. NEJM, 2002.

16. Case 1
A 30 year old woman presents with progressive exercise tolerance for the last 3 months. She ran a marathon at age 26, but now has shortness of breath walking up 1 flight of stairs. She denies chest pain, orthopnea or PND but has intermittent mild ankle edema.

17. Case1
Her blood pressure is normal and her exam is unremarkable. Her EKG and CXR are shown. What test should be ordered next?
A treadmill stress test
Pulmonary function testing
A blood test for BNP
A CT scan of the chest
An echocardiogram

18. Electrocardiogram

19. Chest XR

20. Case 1 What test should be ordered next? A treadmill stress test
Pulmonary function testing
A blood test for BNP
A CT scan of the chest
An echocardiogram

21. Case 1
An echocardiogram is performed.

22. Echocardiogram

23. Case 1 The next best step is to: Start sildenafil 20 mg TID
Send the patient for a right heart catheterization
Send tests for rheumatologic disease
Start an ACE Inhibitor

24. Hemodynamics RA (mmHg) 9 PA (mmHg) 92/44 (65) PCWP (mmHg) 7 CO (L/min)3
PVR (Wood Units) 19

25. Right Sided Heart Failure
Most commonly associated with left sided heart failure
Pulmonary hypertension is another common cause

26. Patients Die From Right Heart Failure

27. WHO Classification of PH
Pulmonary arterial hypertension
Idiopathic
Heritable
Drug/toxin induced
Associated (HIV, CTD, CHD, schistosomiasis)
I′. PVOD, PCH
PH from left heart disease
Systolic dysfunction
Diastolic dysfunction
Valvular disease
PH from lung disease or hypoxemia
ILD
COPD
OSA
Altitude
CTEPH
Multifactorial
Hematologic
Systemic (sarcoid, vasculitis)
Metabolic (glycogen storage)
Other (tumor)

28. Localization of Abnormalities
University of Michigan website
Dijke. Nature Reviews Molecular and Cell Biology

29. Right Heart Dysfunction
Progression of PAH
PAP
PVR CO
Time
Pre-symptomatic/ Compensated
Symptomatic/ Decompensating
Symptom Threshold
Right Heart Dysfunction
Declining/ Decompensated
CO =

30. Targets for Therapies in Pulmonary Arterial Hypertension
Figure 1. Targets for Current or Emerging Therapies in Pulmonary Arterial Hypertension. Three major pathways involved in abnormal proliferation and contraction of the smooth-muscle cells of the pulmonary artery in patients with pulmonary arterial hypertension are shown. These pathways correspond to important therapeutic targets in this condition and play a role in determining which of four classes of drugs -- endothelin-receptor antagonists, nitric oxide, phosphodiesterase type 5 inhibitors, and prostacyclin derivatives -- will be used. At the top of the figure, a transverse section of a small pulmonary artery (
Humbert. NEJM, 2004.

31. Acute Pulmonary Embolism

32. Case 2
A 68 year old HTN, diabetic female presents with progressive shortness of breath over the last 5 years. She can walk about 2 blocks before needing to rest.

33. Case 2
The examination shows tachycardia and a normal blood pressure. There are bibasilar crackles and an S3 on exam.

34. EKG

36. Case 2
There was trace LE edema. The EKG shows LVH. An echocardiogram shows LVH and severe diastolic dysfunction.

37. Case 2 The next best step is: A nuclear stress test
Aggressive blood pressure management
A coronary angiogram
Aggressive management of diabetes

38. Diastolic Heart Failure
Nearly ½ of all patients with heart failure
65% 5 year mortality
Shah. JAMA, 2008.

39. Typical Features Of Patients With Diastolic Heart Failure
Female: 62-66%
Elderly: mean age 72-74
Comorbidities
CAD 36-53%
HTN 55-77%
AF 32-41%
DM 32-45%
CKD 23-26%
Obesity
Anemia

40. Mortality In Diastolic Heart Failure Is High
4596 patients over 15 years
Owan. NEJM, 2006.

41. Diastolic Heart Failure: Elevated LV Filing Pressures
Nagueh. JASE, 2009.

42. What Does DHF Look Like On Echo?
Nagueh. JASE, 2009.

43. Treatment
Treatment of comorbidities