Reversal of the pattern of respiratory variation of Doppler inflow velocities in constrictive pericarditis during mechanical ventilation

When is tamponade not an echocardiographic diagnosis… Or is it ever?

Although cardiac tamponade remains a clinical diagnosis, echocardiography is an essential tool to detect fluid in the pericardial space. Interpretation of echocardiographic findings and assessment of physiologic and hemodynamic consequences of a pericardial effusion require a thorough understanding of pathophysiologic processes. Certain echocardiographic signs point toward the presence of cardiac tamponade: a dilated inferior vena cava (IVC), collapse of the cardiac chambers, an inspiratory bulge of the interventricular septum into the left ventricle (LV) (the "septal bounce"), and characteristic respiratory variations of Doppler flow velocity recordings. However, in certain circumstances (e.g., mechanical ventilation, post-surgical patients, and pulmonary hypertension), these echocardiographic signs can be missing, despite the presence of clinical tamponade. Failure to recognize a potentially life-threatening clinical condition due to the absence of corresponding echocardiographic findings can delay both diagnosis and life-saving treatment. Thus, in the context of critical care, echocardiography should only be used to confirm the presence of pericardial fluid or localized hematoma, and the diagnosis of tamponade should rely on clinical criteria.

Pericardiectomy for Constrictive Pericarditis: Analysis of Outcomes

Constrictive pericarditis is caused by pericardial inflammation and fibrosis, leading to diastolic heart failure. The diagnosis requires a high index of suspicion because it often can mimic restrictive myocardial disease and cardiac tamponade and can be associated with severe tricuspid regurgitation and chronic liver disease. Patients who remain undiagnosed can experience a 90% mortality rate, and for those who undergo pericardiectomy, the survival rate varies significantly, depending on the underlying etiology and preoperative functional class of the patient. In this article, the authors review the pathophysiology, echocardiographic findings, management, and surgical outcomes of constrictive pericarditis to aid the cardiothoracic anesthesiologist in the perioperative management of this disorder.

Guidelines for the Use of Transesophageal Echocardiography to Assist with Surgical Decision-Making in the Operating Room: A Surgery-Based Approach: From the American Society of Echocardiography in Collaboration with the Society of Cardiovascular Anesthesiologists and the Society of Thoracic Surgeons

Intraoperative transesophageal echocardiography is a standard diagnostic and monitoring tool employed in the management of patients undergoing an entire spectrum of cardiac surgical procedures, ranging from "routine" surgical coronary revascularization to complex valve repair, combined procedures, and organ transplantation. Utilizing a protocol as a starting point for imaging in all procedures and all patients enables standardization of image acquisition, reduction in variability in quality of imaging and reporting, and ultimately better patient care. Clear communication of the echocardiographic findings to the surgical team, as well as understanding the impact of new findings on the surgical plan, are paramount. Equally important is the need for complete understanding of the technical steps of the surgical procedures being performed and the complications that may occur, in order to direct the postprocedure evaluation toward aspects directly related to the surgical procedure and to provide pertinent echocardiographic information. The rationale for this document is to outline a systematic approach describing how to apply the existing guidelines to questions on cardiac structure and function specific to the intraoperative environment in open, minimally invasive, or hybrid cardiac surgery procedures.

Systematic review of non-invasive cardiovascular imaging in the diagnosis of constrictive pericarditis

Background

Diagnosis of constrictive pericarditis (CP) can be challenging. It can be nearly impossible to distinguish CP from other causes of right heart failure. Although various imaging modalities help in the diagnosis, no test is definitive. Several reviews have addressed the role of various imaging techniques in the diagnosis of CP but a systematic review has not yet been published.

Objective

Our intention was to study the ability of various non-invasive imaging modalities to diagnose CP in patients with surgically confirmed disease and to apply our findings to develop a clinically useful diagnostic algorithm.

Methods

A PubMed (NLM) search was performed with MeSH term “constrictive pericarditis”. Original articles that investigated the ability of various cardiovascular imaging modalities to noninvasively diagnose surgically confirmed CP were included in our review. Investigations that included any cases without surgical confirmation were excluded.

Results

The PubMed search yielded 3001 results with MeSH term “constrictive pericarditis” (January 8, 2016). We identified (40) studies on CP that matched our inclusion criteria. We summarized our results sorted by individual non-invasive CV imaging modalities – echocardiography, cardiac computed tomography (CT), and magnetic resonance imaging (MRI). Under each imaging modality, we grouped our discussion based on different parameters useful in CP diagnosis.

Conclusions

In conclusion, contemporary diagnosis of CP is based on clinical features and echocardiography. Cardiac MRI is recommended in patients where echocardiography is not diagnostic. Both cardiac MRI and CT can guide surgical planning but we prefer MRI as it provides both structural and functional information.

A systematic approach to evaluation of pericardial effusion and cardiac tamponade

Pericardial disease leading to pericardial effusion (PEF) is a common condition encountered by the clinician in day-to-day practice. If the PEF becomes large enough, it can cause hemodynamic compromise, resulting in a cardiogenic shock state known as cardiac tamponade. There are many clinical and echocardiographic signs that a clinician can use to assess whether a large PEF is hemodynamically significant. However, these signs can be either conflicting or even absent. The purpose of this review is to first, describe the physiology of the pericardium in health and how it changes with disease; second, outline the pathophysiology of pericardial tamponade and discuss how it is responsible for the physical and echocardiographic findings of cardiac tamponade; and third, suggest an approach to applying these findings in a systematic order to ensure a correct diagnosis.

Effects of positive-pressure ventilation, pericardial effusion, and cardiac tamponade on respiratory variation in transmitral flow velocities

OBJECTIVE

To determine the effects of positive-pressure ventilation and experimentally induced pericardial effusion and tamponade on transmitral flow velocities in dogs.

DESIGN

Descriptive.

SETTING

University laboratory.

PARTICIPANTS

Eleven tracheally intubated and mechanically ventilated dogs.

INTERVENTIONS

Experimental pericardial effusion and cardiac tamponade were created by pericardial injection of warm saline.

MEASUREMENTS AND MAIN RESULTS

Hemodynamic parameters and pericardial pressures were monitored in the 11 dogs. Pulsed-wave Doppler tracings of mitral valve flow were obtained at the leaflet tips along with hemodynamic measurements at 4 stages: control, effusion (no decrease in mean arterial pressure), tamponade (>or=40% decrease in mean arterial pressure), and tamponade relief (after evacuation of pericardial fluid). Maximal variation (36%) in transmitral flow velocity over the respiratory cycle during positive-pressure ventilation was seen in the control stage. In the effusion and tamponade stages, variation in transmitral flow velocity decreased progressively to 29% (p = 0.1804, not significant) and 16% (p < 0.0001), respectively.

CONCLUSION

Intrathoracic pressure and lung volume changes caused by positive-pressure ventilation influence transmitral flow velocity patterns. Respiratory variation in transvalvular flow is pronounced during standard positive-pressure mechanical ventilation, decreases in the presence of pericardial effusion, and becomes almost nonexistent when cardiac tamponade is present. These findings show that the echocardiographic criteria used to diagnose cardiac tamponade based on mitral valve inflow patterns are different during positive-pressure ventilation from spontaneously breathing subjects.