Clinical Editor's Corner: Kern

Constrictive Pericardial Hemodynamics Made Easy

Morton J. Kern, MD, MSCAI, FACC, FAHA

Clinical Editor; Chief of Cardiology, Long Beach VA Medical Center, Long Beach, California; Professor of Medicine, University of California, Irvine Medical Center, Orange, California 

Morton J. Kern, MD, MSCAI, FACC, FAHA

Clinical Editor; Chief of Cardiology, Long Beach VA Medical Center, Long Beach, California; Professor of Medicine, University of California, Irvine Medical Center, Orange, California 

Join Dr. Kern in a 30-minute "Clinical Editor's Corner: Live" discussion on constrictive pericarditis! Tuesday, September 29th (Please note change in date from the print notification) at 12pm ET. Register here.

 

Editor's Note: Table 1 is a corrected version from the print version. This online version of Table 1 and the PDF available for download have been corrected. CLD apologizes for the error.
 

In this issue of CLD, Manjunath et al present a case of a woman who presented with heart failure due to constrictive pericarditis. She had been treated with chemotherapy and chest radiation therapy for Hodgkin’s lymphoma. The diagnosis was suspected by the clinical presentation of dyspnea, neck vein elevation, pedal edema (and perhaps ascites), and by cardiac imaging (computed tomography [CT], echo, magnetic resonance imaging [MRI]) data. The final diagnosis was confirmed by hemodynamics. Since constrictive pericardial pathophysiology can be confusing, I thought this would be a good time to make the hemodynamics easier to understand. 

The Pathophysiology of Constrictive Pericarditis

Constrictive pericarditis is the result of encasement of the heart by a thick and inelastic pericardium that limits the heart volume (Figure 1). Cardiac filling occurs until the pericardium can stretch no further. Hemodynamically, this limit to cardiac filling can easily been seen in the left ventricular (LV) and right ventricular (RV) diastolic filling pattern called the ‘dip and plateau’, where the early ventricular filling wave is exaggerated (the dip), then filling abruptly stops, with a leveling of the diastasis (the plateau) (Figure 2). There are other findings relating RV to LV pressure, but these are not very specific to help differentiate constrictive from restrictive physiology (Table 1), except the findings of dynamic respiratory hemodynamic variations.1 

What is Dynamic Respiratory Variation?

In the normal heart with a thin and elastic pericardial membrane, inspiration increases inflow into both ventricles equally. However, in a heart with a fixed volume due to a constrictive pericardium, during inspiratory filling of the RV, the septum shifts into the LV, and LV filling (and pressure) is reduced. During expiration, the reverse occurs, with the septum shifting back toward the RV, reducing the volume and systolic pressure in the RV at a time when systolic pressure in the LV is increasing (Figure 3). The changes of systolic RV/LV pressure over the respiratory cycle are called dynamic respiratory variations. In constrictive pericarditis, the dynamic respiratory variation is discordant; that is, the LV pressure is rising out of synchrony with the RV pressure lagging and falling. The reverse occurs during expiration. Concordant pressure responses between the RV/LV are seen in normal hearts and in those with restrictive cardiomyopathy. Both RV and LV systolic pressure rise and fall in synchrony or concordantly. Of all the hemodynamic signs used to differentiate constriction from restriction (Table 1), the dynamic respiratory responses are the most sensitive, specific, and have the highest positive and negative predictive value. 

Hurrell et al2 were the first to describe the ventricular respiratory discordance on the first 2 beats during inspiration/expiration in 16 surgically proven cases of constrictive pericardial disease (Figure 4). Since many of the associated hemodynamic findings, like the classic dip and plateau, are also present in restrictive cardiomyopathy or RV infarction, concordant and discordant dynamic respiration interactions can differentiate restrictive from constrictive physiology with high sensitivity and specificity. Figure 5 demonstrates a refinement of the measurements of dynamic respiratory interaction, showing discordant changes in areas under the LV and RV pressure curves in patients with constrictive physiology compared to patients with restrictive cardiomyopathy.3 

Hemodynamic Waveforms of Constricted Physiology vs Tamponade

For a quick review, recall that tamponade compresses the heart and elevates all chamber pressures with near end-diastolic equilibration. Unlike constriction, cardiac tamponade blunts both the X and Y descents of atrial waveforms (Figure 6, left). In constrictive pericarditis (Figure 6, right), pericardial constraint permits early rapid LV filling with a sudden cessation of further filling over diastasis, ie, the early ‘dip’, followed by a diastolic plateau in both the RV and LV diastolic filling pattern. The right atrial pressure waveform has a steep X and Y descent and W configuration. There is some overlap of hemodynamic filling patterns during early and mid-phases of tamponade.

Diagnostic Imaging Studies for Constrictive Pericarditis

The diagnosis of constrictive pericarditis always begins with the clinical story, followed by non-invasive imaging (Figure 7). Often, echocardiography is first followed by CT and then MRI. In the case described in this issue of CLD by Manjunath et al, echocardiography showed moderately reduced LV systolic function. Additional findings on echocardiography are shown on Table 2. 

The blood flow across the tricuspid and mitral valves reflect the same phenomenon described for the dynamic hemodynamic pressure responses.4 These findings are evident in Doppler flow velocities, as indicated by >25% expiratory increase in mitral early diastole (the E wave) (E) velocity and expiratory decrease in hepatic vein diastolic flow velocity, and >25% increase in diastolic flow reversals compared with inspiratory velocity. Discordant changes in tricuspid/mitral flow velocities are consistent with constriction. The septal bounce is the visualization of the cardiac volume reaching the limit of the pericardium. In addition, marked hepatic vein diastolic flow reversal with expiration is highly suggestive of the diagnosis.

Next, the chest CT in the case showed post-radiation fibrosis, bilateral pleural effusions, and incidental patchy pericardial calcifications that suggested the presence of pericardial involvement. Most diagnostic finding via CT is the thickened pericardium.

MRI

Cardiac magnetic resonance imaging (MRI), the imaging modality of choice, demonstrated a small pericardial effusion with mild thickening of the pericardium and a septal ‘bounce’, a specific finding suggesting the heart is confined to the restricted pericardial volume, and the physiology of the right and left ventricles depends on reciprocal filling during respiration (again demonstrating interdependence).5 The dynamic MRI images often illustrate the thickened, adherent pericardium limiting the efficient motion of the ventricles within the pericardium, as compared to normal pericardial function showing a smooth sliding in the lubricated pericardium during the cardiac cycle. MRI also may demonstrate respiratory variation in the septal position characterized by a septal bounce that correlates with echocardiographic M-mode pattern. In establishing the definitive diagnosis, MRI also can identify intrinsic myocardial disease (eg, amyloid infiltration) that may sway the diagnosis toward restrictive cardiomyopathy over pericardial disease. 

The Bottom Line

A constricted pericardium prevents the ventricles from filling fully and equally. The fixed cardiac volume and the isolation from the intrathoracic pressure result in dynamic respiratory variations of RV/LV systolic pressures. 

Discordant RV/LV systolic pressures during respiration is diagnostic for constrictive physiology; concordant pressures can be normal or part of restrictive myocardiopathy. The ‘dip and plateau’ sign screens for the possibility of constrictive physiology, but is not diagnostic. Figure 8 provides an algorithm for the approach to the diagnosis and management of constrictive pericarditis and restrictive cardiomyopathy. 

Disclosures: Dr. Morton Kern reports he is a consultant for Abiomed, Abbott Vascular, Philips Volcano, ACIST Medical, and Opsens Inc. 

Dr. Kern can be contacted at mortonkern2007@gmail.com.

On Twitter @drmortkern

References
  1. Kern MJ, Goldstein JG, Lim MJ (ed). Hemodynamic rounds: interpretation of cardiac pathophysiology from pressure waveform analysis. 4th Edition. Wiley-Liss, New York, 2017.
  2. Hurrell DG, Nishimura RA, Higano ST, et al. Value of dynamic respiratory changes in left and right ventricular pressures for the diagnosis of constrictive pericarditis. Circulation. 1996; 93(11): 2007-2013. doi:10.1161/01.cir.93.11.2007
  3. Geske JB, Anavekar NS, Nishimura RA, Oh JK, Gersh BJ. Differentiation of constriction and restriction: complex cardiovascular hemodynamics. J Am Coll Cardiol. 2016; 68(21): 2329-2347. doi:10.1016/j.jacc.2016.08.050
  4. Oh JK, Hatle LK, Seward JB, et al. Diagnostic role of Doppler echocardiography in constrictive pericarditis. J Am Coll Cardiol. 1994; 23(1): 154-162. doi:10.1016/0735-1097(94)90514-2
  5. Miller CA, Dormand H, Clark D, Jones M, Bishop P, Schmitt M. Comprehensive characterization of constrictive pericarditis using multiparametric CMR. JACC Cardiovasc Imaging. 2011; 4(8): 917-920. doi:10.1016/j.jcmg.2011.01.023
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