Hmmmm.... what's that on the CXR?

One evening, a 50-something year old male with heart failure is slotted into a room with a chief complaint of "medication refill".   Surprisingly, he is triaged as a "B" acuity.  You click open the chart and quickly realize why - the patient has run out of his home dobutamine infusion.

The patient is initially dyspneic, but his symptoms improve after re-initiation of dobutamine.  A Chest X-ray is obtained during the course of his ED stay.  You decide to seize the teaching opportunity and begin to review the features of the patient's CXR with the medical student on shift. 

However, when you look closer at the left border of the heart, you note something that you do not immediately recognize:

What is visible in the close up image?  What purpose is it intended to serve?

Scroll down for the Case Conclusion.

 

 

 

 

 

 

 

Final Diagnosis: Ventricular Mesh (CorCap Cardiac Support Device)

Case Conclusion:  On the close up view of the left ventricular border,  there is a lacy, organized material overlying the ventricle.   The patient has a  CorCap Cardiac Support device in place to treat his severe combined systolic and diastolic heart failure.  Eventually, the patient underwent an LVAD placement as a bridge to transplant, and subsequently underwent successful orthotropic heart transplant.

Learning Points: Heart Failure is a progressive disease accompanied by maladaptive ventricular remodeling.  As cardiac injury compromises contractility, the heart dilates to maintain cardiac stroke volume.  Increased ventricular diameter in turn increases ventricular wall stress by Laplace’s equation (Wall stress = LV end diastolic pressure x wall chamber radius/wall thickness).  The increase in wall stress then increases the force required from each individual muscle cell to produce any given intraventricular pressure  [1].  

Many of the treatments for heart failure are aimed at halting, temporizing or reversing this maladaptive cycle of ventricular remodeling.  These treatments include medical therapy (ACE inhibitors, diuretics, aldosterone receptor antagonists and beta-blockers) and cardiac resynchronization therapy which uses biventricular stimulation with a pacemaker to resynchronize ventricular contraction and improve systolic function.   When a patient’s disease progresses despite these therapies, there are several surgical options including ventricular restoration surgery,  passive ventricular support  (CorCap external fabric mesh containment device) and Ventricular Assist Devices (LVAD) [2,3].

        Image from Reference [3]

Prior to LVAD placement, this patient underwent surgical placement of passive ventricular support to stem further ventricular dilation. Such cardiac support devices were initially developed and tested in animal models where they were found to promote reverse remodeling.  The largest clinical trial of passive ventricular support in heart failure patients was the Acorn Randomized Trial.  In this trial, 300 adult patients with NYHA Class III-IV heart failure with an ejection fraction of < 35% , enlarged end-diastolic dimension, and already on optimized medical therapy were randomized to undergo (n=148) or not undergo (n=152) placement of ventricular mesh.  At 12 months of follow-up, more treatment patients were considered improved  (defined as being alive, had not experienced a major cardiac procedure and had improved by at least on NYHA class) and fewer were considered worsened  (died, required a major cardiac procedure or deteriorated by at least one NYHA class) when compared with the control group [4].  

 Source: Reference [4]

Source: Reference [4]

Of this composite endpoint, the most significant decrease was in the need for another major cardiac procedure (21 vs. 48 procedures, p < 0.01).  This included fewer patients with cardiac transplants (7 vs. 16) and LVAD implants (3 vs. 8) in the treatment group.  However, it is possible that the previous surgery may have played a role in assessing the risks/benefits of additional procedures.  Patients who had undergone the treatment were also found to have decreased LV volumes and sphericity, which was again found in a three-year follow-up study [5].  While three-year and five-year follow-up studies found no significant difference in overall mortality or left ventricular ejection fraction between treatment and control groups,  there was a significant improvement in NYHA functional class and reduction of further cardiac procedures in the treatment group [6]. No patients developed the feared complication of constriction.

Related educational materials:

- LVAD patients: What you need to know (emdocs)

- A review of the why and how of cardiac resynchronization therapy in the journal Circulation

Case Conclusion by Maia Dorsett (@maiadorsett)

References

  1. Walsh, R. G. (2005). Design and Features of the Acorn CorCapTM Cardiac Support Device: The Concept of Passive Mechanical Diastolic Support. Heart failure reviews, 10(2), 101-107.
  2. Haeck, M. L. A., Hoogslag, G. E., Rodrigo, S. F., Atsma, D. E., Klautz, R. J., van der Wall, E. E., ... & Verwey, H. F. (2012). Treatment options in end-stage heart failure: where to go from here?. Netherlands Heart Journal, 20(4), 167-175.
  3. Cheng, A., Nguyen, T. C., Malinowski, M., Langer, F., Liang, D., Daughters, G. T., ... & Miller, D. C. (2006). Passive ventricular constraint prevents transmural shear strain progression in left ventricle remodeling. Circulation, 114(1 suppl), I-79.
  4. Mann, D. L., Acker, M. A., Jessup, M., Sabbah, H. N., Starling, R. C., & Kubo, S. H. (2007). Clinical evaluation of the CorCap Cardiac Support Device in patients with dilated cardiomyopathy. The Annals of thoracic surgery, 84(4), 1226-1235.
  5. Starling, R. C., Jessup, M., Oh, J. K., Sabbah, H. N., Acker, M. A., Mann, D. L., & Kubo, S. H. (2007). Sustained benefits of the CorCap Cardiac Support Device on left ventricular remodeling: three year follow-up results from the Acorn clinical trial. The Annals of thoracic surgery, 84(4), 1236-1242.
  6. Mann, D. L., Kubo, S. H., Sabbah, H. N., Starling, R. C., Jessup, M., Oh, J. K., & Acker, M. A. (2012). Beneficial effects of the CorCap cardiac support device: five-year results from the Acorn Trial. The Journal of thoracic and cardiovascular surgery, 143(5), 1036-1042.