Changes in left atrial mechanics following pericardiectomy for pericardial constriction

Echocardiographic Differentiation of Pericardial Constriction and Left Ventricular Restriction

PURPOSE OF REVIEW

Overlapping hemodynamics in constrictive pericarditis (CP) and restrictive cardiomyopathy (RCM) often pose difficulties in establishing accurate diagnosis. Echocardiography is the first-line imaging modality used for this purpose, but no single echocardiographic parameter is sufficiently robust for distinguishing between the two conditions. The newer developments may improve the diagnostic accuracy of echocardiography in this setting.

RECENT FINDINGS

Recent studies have validated multiparametric algorithms, based on conventional echocardiographic parameters, which enable high sensitivity and specificity for distinguishing between CP and RCM. In addition, myocardial deformation analysis using speckle-tracking echocardiography has revealed distinct pattern of abnormalities in the two conditions. CP is characterized by impaired left ventricular apical rotation with relatively preserved longitudinal strain, esp. of ventricular and atrial septum. In contrast, RCM results in global and marked impairment of left ventricular longitudinal strain with initially preserved circumferential mechanics. Combining multiple echocardiographic parameters into step-wise algorithms and incorporation of myocardial deformation analysis help improve the diagnostic accuracy of echocardiography for distinguishing between CP and RCM. The use of machine-learning may allow easy integration of a wide range of echocardiographic and clinical parameters to permit accurate, automated diagnosis, with less dependence on the user expertise.

Pericardiectomy and Pericardial Window for the Treatment of Pericardial Disease in the Contemporary Era

PURPOSE OF REVIEW

To summarize the contemporary practice of pericardiectomy and pericardial window. We discuss the indications, preoperative planning, procedural aspects, postprocedural management, and outcomes of each procedure.

RECENT FINDINGS

Surgical approaches for the treatment of pericardial disease have been around even before the emergence of cardiopulmonary bypass. Since the forthcoming of cardiopulmonary bypass, there have been significant changes in the epidemiology and diagnostic approach of pericardial diseases as well as advancements in the surgical techniques and perioperative management used in the care of these patients. Pericardiectomy has an average mortality of almost 7% and is typically performed in patients with advanced symptoms from constrictive pericarditis and relatively few comorbidities. Pericardial window is a safe procedure for the treatment of pericardial effusion that can be performed with different approaches.

Mechanical Interaction of the Pericardium and Cardiac Function in the Normal and Hypertensive Rat Heart

The pericardium is a thin connective tissue membrane that surrounds the heart and is an integral regulatory component of cardiopulmonary performance. Pathological growth and remodeling of the right ventricle (RV) stemming from structural heart diseases are thought to include a significant role of the pericardium, but its exact role remains unclear. The objective of this study was to investigate potential biomechanical adaptations of the pericardium in response to pulmonary hypertension and their effects on heart behavior. Integrated computational-experimental modeling of the heart offers a robust platform to achieve this objective. We built upon our recently developed high-fidelity finite-element models of healthy and hypertensive rodent hearts via addition of the pericardial sac. In-silico experiments were performed to investigate changes in pericardium reserve elasticity and their effects on cardiac function in hypertensive hearts. Our results suggest that contractile forces would need to increase in the RV and decrease in the left ventricle (LV) in the hypertensive heart to compensate for reductions in pericardium reserve elasticity. The discrepancies between chamber responses to pericardium addition result, in part, from differences in the impact of pericardium on the RV and LV preload. We further demonstrated the capability of our platform to predict the effect of pericardiectomy on heart function. Consistent with previous results, the effect of pericardiectomy on the chamber pressure-volume loop was the largest in the hypertensive RV. These insights are expected to motivate further computational investigations of the effect of pericardiectomy on cardiac function which remains an important factor in surgical planning of constrictive pericarditis and coronary artery bypass grafting.

Evaluation of Long-Term Impact of Pericardiectomy on Left Atrial Functions in Patients with Constrictive Pericarditis Using Speckle Tracking Echocardiography

The aims of this study were to explore the long-term impact of pericardiectomy on left atrial (LA) functions in patients with constrictive pericarditis (CP) using speckle tracking echocardiography (STE) and to correlate post-operative LA functions with clinical status. Echocardiographic examinations were undertaken in 29 patients with CP 1 wk before and 1, 6 and 12 mo after pericardiectomy. STE was performed to obtain LA global longitudinal strain, including strain during the conduit phase (LAScd), strain during the contraction phase (LASct) the sum of the latter and strain during the reservoir phase (LASr). Control patients consisted of 29 age- and sex-matched healthy volunteers. LASct, LAScd and LASr obtained 6 mo after pericardiectomy improved significantly compared with pre-operative values, but were still lower than the values for control patients. Further increases were observed gradually with normalization of LASct 12 mo after pericardiectomy. However, there were still significant differences between LAScd and LASr obtained in control patients and those obtained 12 mo after pericardiectomy. Moreover, the improvements in LAScd, LASct and LASr 12 mo after pericardiectomy correlated well with symptomatic clinical alleviation (p < 0.01). These results indicate that LA strains analyzed with STE might be useful in evaluating the long-term impact of pericardiectomy on LA functions.

Re-pericardiectomy for recurrent chronic constrictive pericarditis: left anterolateral thoracotomy is a better approach

Background

Pericardiectomy is the final treatment for constrictive pericarditis. However, this greatest surgical approach is still very controversial. This study pursued to assess the outcomes in patients with recurrent chronic constrictive pericarditis undergoing reoperated pericardiectomy via median sternotomy versus left anterolateral thoracotomy and to explain which surgical approaches might be better for recurrent chronic constrictive pericarditis.

Methods

A total of 24 patients were identified with recurrent chronic constrictive pericarditis and underwent reoperation with pericardiectomy between July 2003 and July 2015. The decision for this surgical approach was mainly dependent on the operating surgeon’s preference. Out of 20 patients, 16 patients underwent pericardiectomy via median sternotomy and 8 patients via left anterolateral thoracotomy pericardiectomy. Their data were obtained retrospectively from the case notes.

Results

Both groups of patients were similar in age, gender between two operations, and also in peripheral venous pressure, cardiac rhythm and New York Heart Association (NYHA) class distribution. The mortality rates were similar in both groups with one death (12.5%) due to low cardiac output syndrome in the left anterolateral thoracotomy group and two deaths (12.5%) in the median sternotomy group. All the deaths were associated with cardiac complications and happened in the perioperative period. NYHA functional class status enhanced in most of the patients. Patients in both groups had a similar and significant improvement in their NYHA status that improved from 3.4 ± 0.7 to 1.8 ± 0.1 (P = 0.001) in the left anterolateral thoracotomy group and reduced from 3.3 ± 0.6 to 1.9 ± 0.4 (P = 0.001) in the median sternotomy group. There was a significantly greater rate of pulmonary infection in the thoracotomy group than in the median sternotomy group (50% versus 25%, P = 0.02). Nevertheless, there was a significantly greater occurrence of wound infections in the median sternotomy group in 3 patients versus in one patient of the left anterolateral thoracotomy group (18.8% versus 12.5%, P = 0.02).

Conclusions

Left thoracotomy incision was preferred to sternotomy in the current setting of this situation and was done safely without CPB. It avoided life-threatening sternal infection and it also has showed an equal as well las significant enhancement of NYHA status of the patients.

Diastolic Stress Testing Along the Heart Failure Continuum

PURPOSE OF REVIEW

This review summarizes recent developments highlighting the clinical utility of diastolic stress testing along the heart failure continuum.

RECENT FINDINGS

Invasive hemodynamic assessment of cardiac filling pressures during physiological stress is the gold-standard technique for unmasking diastolic dysfunction. Non-invasive surrogate techniques, such as Doppler ultrasound, have shown excellent agreement with invasive approaches and are now recommended by the American Society of Echocardiography and the European Association of Cardiovascular Imaging. While cycle exercise is often advocated, recent evidence supports the use of isometric handgrip as a viable alternative stressor. Diastolic stress testing is a powerful tool to enhance detection of diastolic dysfunction, is able to differentiate between cardiac and non-cardiac pathology, and should be incorporated into routine clinical assessment.

New Cardiac Imaging Algorithms to Diagnose Constrictive Pericarditis Versus Restrictive Cardiomyopathy

PURPOSE OF REVIEW

Echocardiography is the mainstay in the diagnostic evaluation of constrictive pericarditis (CP) and restrictive cardiomyopathy (RCM), but no single echocardiographic parameter is sufficiently robust to accurately distinguish between the two conditions. The present review summarizes the recent advances in echocardiography that promise to improve its diagnostic performance for this purpose. The role of other imaging modalities such as cardiac computed tomography, magnetic resonance imaging, and invasive hemodynamic assessment in the overall diagnostic approach is also discussed briefly.

RECENT FINDINGS

A recent study has demonstrated improved diagnostic accuracy of echocardiography with integration of multiple conventional echocardiographic parameters in to a step-wise algorithm. Concurrently, the studies using speckle-tracking echocardiography have revealed distinct and disparate patterns of myocardial mechanical abnormalities in CP and RCM with their ability to distinguish between the two conditions. The incorporation of machine-learning algorithms into echocardiography workflow permits easy integration of the wealth of the diagnostic data available and promises to further enhance the diagnostic accuracy of echocardiography. New imaging algorithms are continuously being evolved to permit accurate distinction between CP and RCM. Further research is needed to validate the accuracy of these newer algorithms and to define their place in the overall diagnostic approach for this purpose.

Normal values and clinical relevance of left atrial myocardial function analysed by speckle-tracking echocardiography: multicentre study

AIMS

The aim of this multicentre study was to determine the normal range and the clinical relevance of the myocardial function of the left atrium (LA) analysed by 2D speckle-tracking echocardiography (2DSTE).

METHODS AND RESULTS

We analysed 329 healthy adult subjects prospectively included in 10 centres and a validation group of 377 patients with left ventricular diastolic dysfunction (LVDD). LA myocardial function was analysed by LA strain rate peak during LA contraction (LA-SRa) and LA strain peak during LA relaxation (LA-Strain). The range of values of LA myocardial function in healthy subjects was LA-SRa -2.11 ± 0.61 s(-1) and LA-Strain 45.5 ± 11.4%, and the lowest expected values of these LA analyses (calculated as -1.96 SD from the mean of healthy subjects) were LA-SRa -0.91 s(-1) and LA-Strain 23.1%. Concerning the clinical relevance of these LA myocardial analyses, LA-SRa and LA-Strain detected subtle LA dysfunction in patients with LVDD, even though LA volumetric measurements were normal. In addition, in these patients we found that the functional class (dyspnoea-NYHA classification) was inversely related to both LA-Strain and LA-SRa.

CONCLUSION

In the present multicentre study analysing a large cohort of healthy subjects and patients with LVDD, the normal range and the clinical relevance of the myocardial function of the LA using 2DSTE have been determined.

Constrictive pericarditis--a curable diastolic heart failure

Constrictive pericarditis can result from a stiff pericardium that prevents satisfactory diastolic filling. The distinction between constrictive pericarditis and other causes of heart failure, such as restrictive cardiomyopathy, is important because pericardiectomy can cure constrictive pericarditis. Diagnosis of constrictive pericarditis is based on characteristic haemodynamic and anatomical features determined using echocardiography, cardiac catheterization, cardiac MRI, and CT. The Mayo Clinic echocardiography and cardiac catheterization haemodynamic diagnostic criteria for constrictive pericarditis are based on the unique features of ventricular interdependence and dissociation of intrathoracic and intracardiac pressures seen when the pericardium is constricted. A complete pericardiectomy can restore satisfactory diastolic filling by removing the constrictive pericardium in patients with constrictive pericarditis. However, if inflammation of the pericardium is the predominant constrictive mechanism, anti-inflammatory therapy might alleviate this transient condition without a need for surgery. Early diagnosis of constrictive pericarditis is, therefore, of paramount clinical importance. An improved understanding of how constrictive pericarditis develops after an initiating event is critical to prevent this diastolic heart failure. In this Review, we discuss the aetiology, pathophysiology, and diagnosis of constrictive pericarditis, with a specific emphasis on how to differentiate this disease from conditions with similar clinical presentations.

Relation between echocardiographically estimated and invasively measured filling pressures in constrictive pericarditis

The ratio of early transmitral flow velocity (E) to mitral annular velocity (E') is considered a predictor of pulmonary capillary wedge pressure (PCWP). In a previous small study, the paradoxical relation between PCWP and E/E' ratio has been described in patients with constrictive pericarditis (CP). We sought to test this paradoxical relation in a larger cohort. We retrospectively identified 49 patients with surgically confirmed CP (40 men; mean age 61 ± 10 years) who underwent right-sided cardiac catheterization with PCWP measurement, preceded by an echocardiographic study. Of these, 48 patients underwent either computed tomography or magnetic resonance imaging to measure pericardial thickness on the lateral side of the left ventricular wall. Mean interval time between echocardiogram and right-sided cardiac catheterization was 1.5 ± 3.8 days. There were no significant correlations between mean, medial, or lateral E/E' and PCWP (r = -0.17, 95% confidence interval [CI] -0.43 to -0.12; r = -0.17, 95% CI -0.43 to -0.12; and r = -0.12, 95% CI -0.39 to -0.17, respectively). Similarly, there was no correlation between mean E/E' and brain natriuretic peptide (Spearman r = -0.17, p = NS). Patients with increased pericardial thickness (defined as >4 mm) had both lower lateral peak systolic annular velocity (S') and lower lateral S' integral (7.8 ± 2.4 vs 9.6 ± 2.4, p = 0.02 and 13.2 ± 4.2 vs 15.9 ± 4.7, p = 0.04, respectively). In patients with CP, there were no correlations between septal, lateral, or mean E/E' and PCWP. In conclusion, E/E' is not predictive of filling pressures in patients with CP, and perhaps the "annulus paradoxus" phenomenon should be revisited. The relation between the mitral annular velocity and thickness of the parietal pericardium may affect this phenomenon.

Fifteen-year experience and outcomes of pericardiectomy for constrictive pericarditis

BACKGROUND AND AIM

Constrictive pericarditis has multiple etiologies and can lead to disabling symptoms and severe heart failure with poor quality of life. Surgical pericardiectomy is the cornerstone of management. All patients undergoing pericardiectomy at our institution were reviewed with the goal of analyzing preoperative and intraoperative factors that may be associated with long-term outcomes.

METHODS

A retrospective review of our cardiac surgery database identified all patients who underwent pericardiectomy for constrictive pericarditis between 1997 and 2012. Demographic, comorbidity, operative, and outcome data were analyzed.

RESULTS

Thirty-six patients underwent pericardiectomy for constrictive pericarditis over 15 years. Etiologies included idiopathic (n = 20, 55.6%), postoperative (n = 11, 30.5%), postradiation (n = 3, 8.3%), and tuberculosis (n = 2, 5.6%). Total pericardiectomy was performed in 35 patients. The average preoperative cardiac index was 2.6 L/min/m(2) with a significant increase to 3.1 L/min/m(2) noted in the immediate postoperative period (p = 0.03). There were no perioperative mortalities. The 1-year, 5-year, 10-year, and 15-year survival rates were 97.2%, 94.6%, 86.5%, and 78.3%, respectively. On multivariate analysis, preoperative heart failure (hazard ratio 2.2, p = 0.06), elevated preoperative total bilirubin (>2.7 mg/dL, hazard ratio 6.8, p = 0.02), and elevated creatinine (>1.4 mg/dL, hazard ratio 3.1, p = 0.05) were risk factors for increased long-term mortality. Kaplan-Meier survival analysis showed a significant decrease in overall survival associated with postradiation etiology (p = 0.05).

CONCLUSIONS

Pericardiectomy can be performed with low mortality and immediate improvement in hemodynamics. Those patients with compromised cardiac output, abnormal hepatic or renal function, or with previous radiation therapy have reduced long-term survival.