Interobserver Agreement of the Echocardiographic Diagnosis of LV Hypertrabeculation/Noncompaction

OBJECTIVES

The aim of the study was to assess interobserver agreement (IOA) between 3 observers from 2 laboratories.

BACKGROUND

IOA of left ventricular hypertrabeculation/noncompaction (LVHT) in adults has only been studied within single echocardiographic laboratories.

METHODS

Echocardiographic recordings with and without LVHT were selected and anonymized. The "not-LVHT" cases were matched for age and systolic function. Each observer reviewed the recordings, blinded to the initial diagnosis and the other observers' results. Pre-defined criteria for LVHT were: 1) >3 prominent trabeculae at end-diastole, distinct from papillary muscles, false tendons, or aberrant bands; 2) a noncompacted part of a 2-layered myocardial structure formed by these trabeculations; 3) a ratio of >2:1 of noncompacted to compacted layer at end-systole; and 4) perfusion of the intertrabecular spaces from the ventricular cavity. IOA was estimated using the kappa measure of concordance.

RESULTS

Cine-loops of 100 patients (42 women, ages 16 to 92 years), 50 from each center, and 51 with LVHT as the initial diagnosis, were reviewed. The left ventricular end-diastolic diameter was 32 to 78 mm, and ejection fraction, 4% to 88%. The observers agreed about presence (n = 29) or absence (n = 36) of LVHT and disagreed in 35 cases. Agreement was higher among the 2 observers from the same laboratory (kappa 0.793 [95% confidence interval (CI): 0.672 to 0.915]) than from different laboratories (kappa 0.628 [95% CI: 0.472 to 0.784], kappa 0.669 [95% CI: 0.521 to 0.818]). The observers agreed with the initial report of LVHT-presence in 53% and of absence in 67%. By reviewing the discordant cases, consensus was achieved about LVHT presence (n = 8) or absence (n = 16); in 11 cases, the diagnosis remained questionable. Discordance was due to poor image quality, lack of views in different apical planes, aberrant bands and chordae tendineae, abnormally sized or inserting papillary muscles, and localized calcifications of the endocardium.

CONCLUSIONS

IOA was substantial for diagnosing LVHT. However, even the application of pre-defined criteria yielded disagreement in 35% of cases; and after mutual review, there were still 11% questionable cases.

Heart transplant outcomes in patients with left ventricular non-compaction cardiomyopathy

BACKGROUND

Left ventricular non-compaction cardiomyopathy (LVNCC) is a rare disease that starts in utero and may progress to heart failure (HF), sometimes requiring orthotopic heart transplantation (OHT). There are limited data addressing characteristics of LVNCC patients that require OHT and their outcomes. We therefore sought to investigate the characteristics and outcomes of LVNCC patients treated with OHT.

METHODS

We queried the United Network for Organ Sharing (UNOS) database for all patients listed for OHT with LVNCC as the primary heart failure etiology between 2000 and 2013. We examined their characteristics at listing and outcomes after OHT and compared the findings with those of patients with idiopathic cardiomyopathy (IDCMP).

RESULTS

We identified 113 patients (43 adults and 70 pediatrics) with LVNCC of 45,298 patients (0.25% overall, 0.11% of adults and 1.0% of pediatrics) listed for OHT in this time period. Most were male children with mean age at listing of 16.9 years. Compared with the overall IDCMP cohort, patients with LVNCC were younger, had higher use of inotropes and extracorporeal membrane oxygenation (ECMO), and were more often listed as UNOS Status 1A with shorter waiting time. However, when adjusted for age, gender and ethnicity, these differences disappeared. During transplant listing, 8 (7.9%) died, 5 (5.0%) improved and avoided transplant, 3 (3.0%) became too sick for transplant and 78 (77.2%) underwent OHT. There was a non-significant trend toward longer cardiac allograft survival in patients with LVNCC (10.6 vs. 9.4 years; log-rank test, p = 0.068). Patients with LVNCC had similar outcomes to other IDCMP patients, except for more post-transplant infections (50.0% vs. 21.6%, p < 0.05).

CONCLUSIONS

LVNCC patients undergoing heart transplantation are mostly pediatric and predominantly bridged to transplant with inotropes or ECMO. Despite having more post-transplant infections, their survival is similar to that of other IDCMP patients.

Comparison of systolic and diastolic criteria for isolated LV noncompaction in CMR

OBJECTIVES

This study used cardiac magnetic resonance (CMR) to compare standard criteria for left ventricular noncompaction (LVNC).

BACKGROUND

LVNC as a distinct cardiomyopathy is supported by a growing number of publications. Echocardiographic and CMR criteria have been established to diagnosis LVNC but have led to concerns of diagnostic accuracy.

METHODS

Trabeculation/possible LVNC by CMR was retrospectively observed in 122 consecutive cases. We compared the standard end-systolic noncompacted-to-compacted ratio (ESNCCR), end-diastolic noncompacted:compacted ratio (EDNCCR), and trabecular mass-to-total mass ratio (TMTMR) along with deaths, embolic events, congestive heart failure (CHF) readmissions, ventricular arrhythmias, myocardial thickening (MT), left ventricular ejection fraction (LVEF), 3-dimensional sphericity index (3DSi), and left ventricular end-diastolic volume index. Adjusting for age, race, sex, body surface area, diabetes mellitus, hypertension, hyperlipidemia, coronary artery disease, and CHF, logistic regression was used to compare combined events (death, CHF readmission, embolism, ventricular arrhythmia) between ESNCCR, EDNCCR, and TMTMR. Adjusting for same covariates except CHF, logistic regression was used to compare the odds of CHF for those who met criteria and those who did not. Using analysis of covariance, adjusted means for LVEF, MT, 3DSi, and left ventricular end-diastolic volume index were generated.

RESULTS

ES criteria had a higher odds ratio (8.6; 95% confidence interval [CI]: 2.5 to 33) for combined events than ED criteria (1.8; 95% CI: 0.6 to 5.8) or TMTMR criteria (3.14; 95% CI: 1.09 to 10.2). The odds ratio of CHF for those who met ESNCCR criteria was 29.4 (95% CI: 6.6 to 125), but the odds ratio of CHF for those who met EDNCCR criteria was 3.3 (95% CI: 1.1 to 9.2). After adjustment, those who met criteria for noncompaction by ESNCCR had a lower LVEF and less MT than those who did not (p = 0.01 and p = 0.003, respectively), but there was no difference between those who met criteria for EDNCCR or the TMTMR criteria and those who did not.

CONCLUSIONS

ES measures of LVNC have stronger associations with events, CHF, and systolic dysfunction than other measures.

Quantification of left ventricular trabeculae using fractal analysis

BACKGROUND

Left ventricular noncompaction (LVNC) is a myocardial disorder characterized by excessive left ventricular (LV) trabeculae. Current methods for quantification of LV trabeculae have limitations. The aim of this study is to describe a novel technique for quantifying LV trabeculation using cardiovascular magnetic resonance (CMR) and fractal geometry. Observing that trabeculae appear complex and irregular, we hypothesize that measuring the fractal dimension (FD) of the endocardial border provides a quantitative parameter that can be used to distinguish normal from abnormal trabecular patterns.

METHODS

Fractal analysis is a method of quantifying complex geometric patterns in biological structures. The resulting FD is a unitless measure index of how completely the object fills space. FD increases with increased structural complexity. LV FD was measured using a box-counting method on CMR short-axis cine stacks. Three groups were studied: LVNC (defined by Jenni criteria), n=30(age 41±13; men, 16); healthy whites, n=75(age, 46±16; men, 36); healthy blacks, n=30(age, 40±11; men, 15).

RESULTS

In healthy volunteers FD varied in a characteristic pattern from base to apex along the LV. This pattern was altered in LVNC where apical FD were abnormally elevated. In healthy volunteers, blacks had higher FD than whites in the apical third of the LV (maximal apical FD: 1.253±0.005 vs. 1.235±0.004, p<0.01) (mean±s.e.m.). Comparing LVNC with healthy volunteers, maximal apical FD was higher in LVNC (1.392±0.010, p<0.00001). The fractal method was more accurate and reproducible (ICC, 0.97 and 0.96 for intra and inter-observer readings) than two other CMR criteria for LVNC (Petersen and Jacquier).

CONCLUSIONS

FD is higher in LVNC patients compared to healthy volunteers and is higher in healthy blacks than in whites. Fractal analysis provides a quantitative measure of trabeculation and has high reproducibility and accuracy for LVNC diagnosis when compared to current CMR criteria.

Ethnic differences in ventricular hypertrabeculation on cardiac MRI in elite football players

PURPOSE

Left ventricular (LV) trabeculation may be more pronounced in ethnic African than in Caucasian (European) athletes, leading to possible incorrect diagnosis of left ventricular non-compaction cardiomyopathy (LVNC). This study investigates ethnic differences in LV hypertrabeculation amongst elite athletes with cardiac magnetic resonance (CMR) and electrocardiography (ECG).

METHODS

38 elite male football (soccer) players (mean age 23.0, range 19-34 years, 28/38 European, 10/38 African) underwent CMR and ECG. Hypertrabeculation was assessed using the ratio of non-compacted to compacted myocardium (NC/C ratio) on long-axis and short-axis segments. ECGs were systematically rated.

RESULTS

No significant differences were seen in ventricular volumes, wall mass or E/A ratio, whereas biventricular ejection fraction (EF) was significantly lower in African athletes (European/African athletes LVEF 55/50 %, p = 0.02; RVEF 51/48 %, p = 0.05). Average NC/C ratio was greater in African athletes but only significantly at mid-ventricular level (European/African athletes: apical 0.91/1.00, p = 0.65; mid-ventricular 0.89/1.45, p < 0.05; basal 0.40/0.46, p = 0.67). ECG readings demonstrated no significant group differences, and no correlation between ECG anomalies and hypertrabeculation.

CONCLUSIONS

A greater degree of LV hypertrabeculation is seen in healthy African athletes, combined with biventricular EF reduction at rest. Recognition of this phenomenon is necessary to avoid misdiagnosis of LVNC.

Left ventricular noncompaction: a 25-year odyssey

Left ventricular noncompaction (LVNC) is a cardiomyopathy associated with sporadic or familial disease, the latter having an autosomal dominant mode of transmission. The clinical features associated with LVNC vary from asymptomatic to symptomatic patients, with the potential for heart failure, supraventricular and ventricular arrhythmias, thromboembolic events, and sudden cardiac death. Echocardiography is the diagnostic modality of choice, revealing the pathognomonic features of a thick, bilayered myocardium; prominent ventricular trabeculations; and deep intertrabecular recesses. Widespread use and advances in the technology of echocardiography and cardiac magnetic resonance imaging are increasing awareness of LVNC, and cardiac magnetic resonance imaging is improving the ability to stage the severity of the disease and potential for adverse clinical consequences. Study of LVNC through research in embryology, imaging, and genetics has allowed enormous strides in the understanding of this heterogeneous disease over the past 25 years.

Refinement of echocardiographic criteria for left ventricular noncompaction

BACKGROUND

Left ventricular hypertrabeculation/noncompaction (LVNC) is a cardiac abnormality whose echocardiographic criteria are still controversial. Cooperation between echocardiographic laboratories may contribute to uniformly accepted criteria, as illustrated by the following pilot study.

METHODS AND RESULTS

Echocardiograms proposed for inclusion into a registry were reviewed. Three experts with 17-26 years experience with LVNC agreed on a common definition of LVNC: 1. >3 prominent trabeculous formations along the left ventricular endocardial border visible in end-diastole, distinct from papillary muscles, false tendons or aberrant bands; 2. trabeculations move synchronously with the compacted myocardium, 3. trabeculations form the noncompacted part of a two-layered myocardial structure, best visible at end-systole; and 4. perfusion of the intertrabecular spaces from the ventricular cavity is present at end-diastole on color-Doppler echocardiography or contrast echocardiography. During 3 sessions 115 cases (37% females, mean 57 years) were reviewed. Eleven patients (18% females, mean 60 years) were excluded because of <4 trabeculations (n=5), lack of a two-layered myocardial structure (n=1) and poor image quality (n=5). The observers agreed on inclusion or exclusion in all cases. Consensus was achieved that measurements of the thickness of the myocardial layers, and calculation of the noncompacted:compacted ratio is not feasible due to a lack of uniformly accepted standards for measurements.

CONCLUSIONS

When diagnosing LVNC, end-systolic as well as end-diastolic images have to be considered. The presence of more than three trabeculations as well as a two-layered myocardium are required. Since these criteria are not anatomically controlled, a comparison of echocardiographic images with pathoanatomic findings for assessing sensitivity and specificity is urgently needed.