The use of echocardiography post heart transplantation

Diastolic function in heart transplant: From physiology to echocardiographic assessment and prognosis

Heart transplant (HTx) still represents the most effective therapy for end-stage heart failure, with a median survival time of 10 years. The transplanted heart shows peculiar physiology due to the profound alterations induced by the operation, which inevitably influences several echocardiographic parameters assessed during these patients’ follow-ups. With these premises, the diastolic function is one of the main aspects to take into consideration. The left atrium (LA) plays a key role in this matter, and that same chamber is significantly impaired with the transplant, with different degrees of altered function based on the surgical technique. Therefore, the traditional echocardiographic evaluation of diastolic function applied to the general population might not properly reflect the physiology of the graft. This review attempts to provide current evidence on diastolic function in HTx starting from defining its different physiology and how the standard echocardiographic parameters might be affected to its prognostic role. Furthermore, based on the experience of our center and the available evidence, we proposed an algorithm that might help clinicians distinguish from actual diastolic dysfunction from a normal diastolic pattern in HTx population.

Ventricular systolic dysfunction with and without altered myocardial contractility: Clinical value of echocardiography for diagnosis and therapeutic decision-making

The inability of one of the two or both ventricles to contract normally and expel sufficient blood to meet the functional demands of the body results from a complex interplay between intrinsic abnormalities and extracardiac factors that limit ventricular pump function and is a major cause for heart failure (HF). Even if impaired myocardial contractile function was the primary cause for ventricular dysfunction, with the progression of systolic dysfunction, additionally developed diastolic dysfunction can also contribute to the severity of HF. Although at the first sight, the diagnosis of systolic HF appears quite easy because it is usually defined by reduction of the ejection fraction (EF), in reality this issue is far more complex because ventricular pumping performance depends not only on myocardial contractility, but also largely on loading conditions (preload and afterload), being also influenced by valvular function, ventricular interdependence, pericardial constraint, synchrony of ventricular contrac-tion and heart rhythm. Conventional echocardiography (ECHO) combined with new imaging techniques such as tissue Doppler and tissue tracking can detect early subclinical alteration of ventricular systolic function. However, no single ECHO parameter reveals alone the whole picture of systolic dysfunction. Multiparametric ECHO evaluation and the use of integrative approaches using ECHO-parameter combinations which include also the ventricular loading conditions appeared particularly useful especially for differentiation between primary (myocardial damage-induced) and secondary (hemodynamic overload-induced) systolic dysfunction. This review summarizes the available evidence on the usefulness and limitations of comprehensive evaluation of LV and RV systolic function by using all the currently available ECHO techniques.

Improving Endo-Myocardial Biopsy by Real-Time Spectral Tissue Sensing: A Feasibility Study

Objective: The aim of this research is to integrate spectral tissue sensing technology inside a cardiac bioptome for real-time measurements of tissue characteristics. Methods: Bioptome tip and handle components were designed and manufactured to house and guide optical fibers. The designed components were assembled on a cardiac bioptome together with optical fibers. A technical feasibility test was carried out to study the functionality of the instrument and the effect of the optical technology on the biopsy performance. Biopsy samples were taken from five different tissue types in a porcine heart and the resulting optical spectra were compared. Results: Spectral tissue sensing fibers were successfully integrated inside a conventional cardiac bioptome. The integrated instrument allowed differentiation between ventricular tissue, blood, and cardiac fat tissue based on blood and fat percentage and amount of scattering. Moreover, differences between scarred and non-scarred tissue were clearly visible. Conclusion: A first step has been made in the use of spectral tissue sensing for the detection of different tissue structures for endo-myocardial biopsy. The instrument was able to differentiate between various tissues, as well as between healthy and diseased cardiac tissues. Future research should focus on measurements of naturally diseased cardiac tissue, repeated measurements with statistical value, and improvements to the instrument design. Significance: Having the ability to measure tissue characteristics prior to acquiring a biopsy sample will not only allow easier positioning of the bioptome at the correct location, but can also prevent sampling undesired tissue or scar tissue from previous biopsies.

Evaluation of the Graft Mechanical Function Using Speckle-Tracking Echocardiography During the First Year After Orthotropic Heart Transplantation

Background

Recent advances in ultrasound strain imaging facilitate more precise monitoring of subtle myocardial changes and thus may allow for more appropriate assessment of myocardium after orthotopic heart transplantation (OHT). This study aimed to explore longitudinal left ventricular (LV) and right ventricular (RV) function by speckle-tracking echocardiography (STE) during a 12-month follow-up period in relation to acute cellular rejection (ACR) degree ≥2R and the response to intense immunosuppressive therapy with intravenous steroids.

Material/Methods

Forty-five adult heart transplant recipients were prospectively assessed at a single center from January 2016 until June 2017. Echocardiography was performed serially at baseline and together with routine biopsies at 2 weeks and 1, 2, 3, 6, 9, and 12 months after OHT. Changes in graft function were evaluated using STE before and during ACR and in the resolving period of ACR.

Results

A total of 220 pairs of biopsy specimens and strain recordings were analyzed. Moderate ACR was seen in 30 biopsies (13.6%). In the serial assessment, longitudinal strain parameters of the LV (global and 4-, 2-, 3-chamber longitudinal strain) and RV (global and free wall longitudinal strain) were decreased at baseline and improved significantly (P<0.001) within 12 months after OHT. The degree of improvement was not influenced by ACR. There were no significant differences in circumferential, radial, or longitudinal strain rate, or mechanical dyssynchrony. Reduced LV and RV longitudinal strain was related to ACR degree 2R and increased significantly (P<0.0005) during 3 days of intravenous methylprednisolone therapy.

Conclusions

Using the STE technique, we have documented an acute improvement in mechanical myocardial function following ACR steroid therapy and a progressive recovery of LV and RV longitudinal function during the first year after OHT.

Post-cardiac transplant recipient: Implications for anaesthesia

The annual heart transplant rate is gradually increasing worldwide. A proportion of this patient population present for an elective or emergency surgery which may or may not be related to the transplanted heart. A MEDLINE search for heart transplant, anaesthesia, adult, paediatric and surgery was conducted to review anaesthetic management for heart transplant recipients. Anaesthesia and perioperative management are different in these cases. A thorough understanding of the physiology of denervated heart, post-transplant morbidities and pharmacology of immunosuppressants is essential for best perioperative management and improved post-operative outcome.