Quantitative assessment of valvular function after cardiac transplantation by pulsed Doppler echocardiography

Adult Renal Transplantation in a Patient 28 Years after Heart Transplantation as a Neonate for Hypoplastic Left Heart Syndrome

We present a case of kidney transplantation in a 28-year-old patient who received a heart transplant at 7 weeks of age due to hypoplastic left heart syndrome. The patient's renal insufficiency was the result of chronic immunosuppression and hypertension. The almost 28-year-old graft demonstrated very good function. This patient represents as one of the longest pediatric cardiac graft recipients living without any significant functional limitations.

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.

Fate of atrioventricular valve function of the transplanted heart

BACKGROUND

Long-term echocardiographic data on quantitative assessment of tricuspid and mitral regurgitation after heart transplantation are scarce.

METHODS AND RESULTS

From November 1992 to December 2008, the medical records for 201 patients (mean age, 42.8±12.4 years, 47 females) who underwent heart transplantation were reviewed. Quantitative assessment of mitral and tricuspid valve function was performed using transthoracic echocardiography through long-term follow-up. A total of 196 (97.5%) patients were evaluated with echocardiography for more than 6 months postoperatively. During a mean echocardiography follow-up duration of 89.9±54.3 months, 23 (11.4%) patients showed either tricuspid regurgitation (TR >mild; n=21, 10.4%) or mitral regurgitation (MR >mild; n=6, 3.0%); 4 (2.0%) patients experienced both significant TR and MR. Freedom from moderate-to-severe TR at 10 years was 85.5±5.1% and 93.4±2.2% for the standard and bicaval techniques, respectively (P=0.531). Freedom from moderate-to-severe MR at 10 years was 96.0±2.7% and 98.6±1.0%, respectively, for the 2 techniques (P=0.252). In multivariate analysis, older-age donor emerged as the only independent predictor of significant TR (hazard ratio 1.06, 95% confidence interval 1.01-1.12, P=0.012).

CONCLUSIONS

The long-term results of atrioventricular function after heart transplantation in adults were excellent regardless of anastomotic technique. Older-age donor was significantly associated with the development of postoperative TR.

Prevalence and risk factors for tricuspid valve regurgitation after pediatric heart transplantation

BACKGROUND

Risk factors for tricuspid regurgitation (TR) after adult orthotopic heart transplantation (OHT) have been reported, although there are no pediatric data.

METHODS

This study was a single-center retrospective analysis of patients <or= 18 years of age who underwent OHT from January 1990 to December 2004. The impact of TR was evaluated with respect to outcomes (graft failure, etc.).

RESULTS

Echocardiograms were available for 99 patients (105 grafts with 6 re-transplants) at a median age of 4.5 years (range 18 days to 17.1 years): 51 (49%) were male; 46 (44%) were transplanted for congenital heart disease; and 76 (72%) had a biatrial anastomosis. Significant TR developed in 30 grafts (29.5%) within a median duration after OHT of 1.2 years (range 0 day to 8.2 years); persistent significant TR until last follow-up was present in 21 grafts (20%). Graft failure (death or need for retransplantation) occurred in 41 grafts (39%), including 14 of 21 grafts (67%) with significant TR. By Kaplan-Meier analysis, freedom from significant TR (95% confidence interval [CI]) at 1, 5 and 10 years was 91.0% (83.4% to 95.2%), 70.2% (55.4% to 80.9%) and 61.5% (39.2% to 77.6%), respectively. No risk factors were identified. Development of significant TR was highly associated with graft failure (p = 0.005).

CONCLUSIONS

Significant TR occurs with comparable frequency in pediatric and adult OHT populations; risk factors identified in adults were not present in our pediatric population. Development of significant TR in pediatric heart transplant recipients is highly associated with graft failure.

Localisation and function of nerves in the aortic root

Neural structures have been shown to be present in valve cusp tissue. We aimed to characterise the influence of neuronal stimulation on the component structures of the aortic root and cusps. Specimens of sinus, sinotubular junction (STJ), annulus and cusp tissue were dissected from porcine aortic roots and either stimulated with electrical field stimulation (EFS) in isolated tissue baths or fixed for immunohistochemical characterisation of neuronal structures. Sinus, STJ and annular tissue all gave tetrodotoxin-sensitive, frequency-dependent contractions in response to EFS. Contractions in annular tissue were only evident in tissue from the left- and non-coronary cusps, but not from the right-coronary cusp. Cusp tissue gave no contractile response to EFS, however in the presence of 1 mumol tetrodotoxin a strong contractile response was evident. This contractile response was unmasked when cusp tissue was stimulated in the presence of a nitric oxide synthase or guanylate cyclase inhibitors. Immunohistochemical analysis identified a network of neurofilament positive fibers in tissue from all aortic root structures that were associated with the presence of tyrosine hydroxylase and choline acetyl transferase. The nerve fibers in cusp tissue were in close proximity to the endothelial surface and demonstrated positive staining for neuronal nitric oxide synthase. Nerves in the aortic valve exert a nitric oxide-mediated neurogenic dilator tone in cusp tissue and are capable of producing contractile responses in different components of the aortic root. These responses could influence valve function in health and disease.

Clinical implications of late mitral valve regurgitation appearance in the follow-up of heart transplantation

BACKGROUND

Tricuspid regurgitation is frequently observed after orthotopic heart transplantation (OHT), in association with severe pulmonary hypertension. However, the incidence of left-sided valvular disease has not been addressed.

AIM

We analyzed the incidence and prognostic implications of left-sided valve disease in 141 patients after OHT.

METHODS

Echocardiography was performed with every endomyocardial biopsy during the first year after OHT and every 6 months thereafter. Mitral regurgitation (MR) grade II or III was considered significant. Graft vasculopathy was assessed using coronary angiography.

RESULTS

Eight patients (6%) developed significant left-sided valvular disease, namely, MR in 6 (4%) and aortic regurgitation (AR) in 2 (1.4%). The 2 cases with AR were diagnosed the first week after OHT, whereas significant MR was diagnosed at mean follow- up of 34 +/- 6 months. Mean regurgitant orifice and volume were 34 +/- 14 mm2 and 41 +/- 15 mL/beat, respectively. Patients with significant MR had experienced a greater number of acute rejection episodes >or=3A, (1.8 +/- 1.7 vs 0.8 +/- 1.05; P = .02) and were associated with allograft vasculopathy in 83% vs 6% among unaffected patients (P = .0001). Four of 6 patients with significant MR died during follow-up (67%) and 1 of the living patients underwent reparative mitral valve surgery. The probability of survival using Kaplan-Meier curves was significantly lower when patients developed late significant MR (54% vs 76%; P = .0001).

CONCLUSIONS

The incidence of significant left-sided valvular disease after OHT was low. MR was associated with a higher degree of previous acute rejection, of graft vasculopathy, and mortality. The presence of moderate or severe MR of late appearance identified a group of OHT patients with poor outcomes.

Echocardiography in the cardiac transplant recipient

Despite the widespread use of echocardiography in the cardiac allograft recipient, the clinical usefulness of this practice is not well defined. In this article, the authors review the spectrum of echocardiographic findings in the adult heart transplant patient. Appreciation of typical alterations from "normal" allows the transplant physician to identify clinically significant changes and to avoid unnecessary invasive procedures based on misinterpretation of these differences. Though abnormalities of systolic and diastolic function correlate with episodes of acute rejection, the primary diagnostic usefulness of echocardiography in acute rejection is guiding the endomyocardial biopsy. Additionally, echocardiography has found a role as a supplement to invasive angiography in the diagnosis of cardiac allograft vasculopathy.

Geometric Disproportion of Cardiac Structure and Graft Ischemia Affect Tricuspid Valve Regurgitation Early After Neonatal Heart Transplantation

BACKGROUND

Although tricuspid valve regurgitation (TR) after heart transplantation is a known complication, there has been little discussion of this subject in neonatal heart transplantation. We aim to elucidate the prevalence, etiology, and evolution of TR early after transplant in neonates.

METHODS

Eighty-five neonatal recipients were studied retrospectively by two-dimensional and Doppler echocardiography. The semiquantitative grading of TR was based on the ratio of regurgitation jet area to right atrial area.

RESULTS

Immediately after neonatal heart transplantation, TR was recognized in 47 patients (grade 1, n = 18; grade 2, n = 22; grade 3, n = 7; and grade 4, n = 0). Tricuspid regurgitation prevalence diminished from 55% to 19% with reduction in severity 1 year after transplantation. The prevalence of TR (grade 2 and grade 3) was affected by a donor/recipient body weight ratio of more than 2.0 (p = 0.004) and graft ischemia for more than 3 hours (p = 0.014). The ratio of donor and recipient right atria portion, which had a correlation with donor/recipient body weight ratio (r2 = 0.415, p < 0.0001), separated the four subgroups in terms of TR grade immediately after transplantation (p = 0.0064) and also at 1 year after transplantation in all surviving grafts from 1.48 +/- 0.54 to 0.8 +/- 0.32 (p < 0.0001). The Cox model found no significance for early posttransplant TR as a risk factor for graft survival.

CONCLUSIONS

Early posttransplant TR was affected by atria geometrical disproportion and by graft ischemia. Tricuspid regurgitation was not a risk factor for graft survival because of its amelioration over time, perhaps induced by recipient growth and recovery of myocardial injury relating to graft procurement.

Echocardiographic evaluation before and after cardiac transplantation

Transplantation of the heart remains a viable option not only as primary treatment for hypoplastic left heart syndrome, but also for end-stage problems after the Norwood sequence of palliations. In this review, I discuss the pre-operative, intra-operative, and post-operative echocardiographic evaluation of these patients, with special emphasis on hemodynamic and functional assessment as well as surveillance for rejection and coronary arterial disease.

Clinical significance of tricuspid valve dysfunction after orthotopic heart transplantation

OBJECTIVES

Tricuspid regurgitation (TR) is common after heart transplantation (OHT), but its clinical relevance is undetermined. This study documents the clinical progress of patients with TR after OHT in relation to the severity of TR.

METHODS

We studied 238 transplant recipients who had survived for at least 12 months after OHT. Tricuspid regurgitation was graded clinically and by assessing regurgitant jet area. Recipients were divided into those with no TR Group 1 (n = 64), those with sub-clinical TR (TR absent clinically and regurgitant jet area <25%, Group 2 (n = 89), and those with clinical TR (with clinical TR or regurgitant jet area > or =25%, Group 3 (n = 85).

RESULTS

We found no significant difference among the groups in terms of age, or pre-operative events. At 12 months after OHT, mean right atrial and pulmonary artery pressures were higher in Group 3 than in Group 1 or Group 2 (p = 0.005 and 0.03, respectively). Right ventricular end-diastolic and end-systolic volumes were smaller for recipients in Groups 1 and 2 compared with those in Group 3 (p = 0.01 and 0.02). The annual development of renal impairment was 0.019 (95% confidence interval [CI], 0.014-0.029), 0.026 (95% CI, 0.022-0.62), and 0.613 (95% CI, 0.346-0.756) in Groups 1, 2, and 3, respectively (p = 0.02). At the most recent follow-up, mean New York Heart Association class for Group 1 was 1.4, for Group 2 was 1.7, and for Group 3 was 2.7 (p = 0.04).

CONCLUSIONS

The integrity of the tricuspid valve has a significant impact on long-term clinical progress of OHT recipients. Recipients with significant TR are more symptomatic and have poorer right-sided heart function compared with those with mild or no TR.

Biological mechanisms influencing the function of the aortic root

Optimal function of the aortic root relies upon the ability of its component structures to move in a coordinated fashion. Some of the cells that make up the structures of the aortic root have been shown to contain nerves, receptors, and contractile elements. The ability to contract or relax may contribute to the successful function of the valve by allowing it to move in a coordinated manner in response to biological stimuli. It is known that cusp tissue receives primary, sensory, and autonomic nerves, suggesting a role for neuronal regulation of cusp function. In addition, cusp tissue has been shown to express a wide variety of receptors and to contract to a range of common vasoactive agents. The cells that constitute the valve have also shown secretory and proliferative responses. The biological signals that mediate the cross-talk between the different parts of the root have not been established. This review will examine the mechanisms that have been documented to be present and to assess their potential contribution in affecting aortic valve function.

Risk factors for tricuspid valve regurgitation after orthotopic heart transplantation

BACKGROUND

Tricuspid regurgitation (TR) may occur following orthotopic heart transplantation (OHT) and although a number of etiological factors have been suggested, the relative contribution of each of these remains to be elucidated. We aimed to assess the risk factors for TR in our 10-year experience of orthotopic heart transplantation (OHT).

METHODS

OHT was performed in 249 patients (161 by the standard technique and 88 by the bicaval technique). TR was assessed using transthoracic color Doppler echocardiography.

RESULTS

Recipients who underwent operation by the standard technique displayed higher incidence of moderate and severe TR than did bicaval-technique recipients. The development of early TR was also correlated to rejection greater than or equal to grade 2, preoperative raised transpulmonary gradient, and raised pulmonary vascular resistance. Risk factors for late TR were standard technique (p < 0.0001), number of rejection greater than or equal to grade 2 (p < 0.004), and the total number of heart biopsies (p < 0.02). Recipients with moderate and severe TR revealed elevated right-side pressures and advanced New York Heart Association statues compared to those with no, trivial, or mild TR.

CONCLUSIONS

Various factors contribute to TR after OHT, the prevalence of which might be lowered by adopting the bicaval technique, early treatment of rejection, and reduction of the number of biopsies performed.