Research Spotlight

Charytan, D. M., R. Foley, P. A. McCullough, J. D. Rogers, P. Zimetbaum, C. A. Herzog, J. A. Tumlin, D. I. Mi and Comm (2016). “Arrhythmia and sudden death in hemodialysis patients: Protocol and baseline characteristics of the monitoring in dialysis study.” Clinical Journal of the American Society of Nephrology 11(4): 721-734.

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Background Dialysis patients have high rates of cardiovascular morbidity and mortality, but data on arrhythmia burden, arrhythmia type, arrhythmia triggers, and the identity of terminal arrhythmias have historically been limited by an inability to monitor heart rhythm for prolonged periods. Objectives To investigate arrhythmia and its association with sudden death in dialysis-dependent ESRD, describe the potential for implantable devices to advance study of dialysis physiology, review the ethical implications of using implantable devices in clinical studies, and report on the protocol and baseline results of the Monitoring in Dialysis Study (MiD). Design, setting, participants, & measurements In this multicenter, interventional-observational, prospective cohort study, we placed implantable loop recorders in patients undergoing long-term hemodialysis. The proportion of patients experiencing clinically significant arrhythmias was the primary endpoint. For 6 months, we captured detailed data on the primary endpoint, symptomatic arrhythmias, other electrocardiographic variables, dialysis prescription, electrolytes, dialysis-related variables, and vital signs. We collected additional electrocardiographic data for up to 1 year. Results Overall, 66 patients underwent implantation in sites in the United States and India. Diabetes was present in 63.6% of patients, 12.1% were age >= 70 years, 69.7% were men, and 53.0% were black. Primary and secondary endpoint data are expected in 2016. Conclusions Cardiac arrhythmia is an important contributor to cardiovascular morbidity and mortality in dialysis patients, but available technology has previously limited the ability to estimate its true burden and triggers and to define terminal rhythms in sudden death. Use of implantable technology in observational studies raises complex issues but may greatly expand understanding of dialysis physiology. The use of implantable loop recorders in MiD is among the first examples of such a trial, and the results are expected to provide novel insights into the nature of arrhythmia in hemodialysis patients.

Roberts, W. C., V. S. Won, A. Vasudevan, J. M. Ko and J. M. Guileyardo (2016). “Frequency of massive cardiac adiposity (floating heart) at necropsy and comparison of clinical and morphologic variables with cases with nonmassive cardiac adiposity at a single texas hospital, 2013 to 2014.” American Journal of Cardiology 117(6): 1006-1013.

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Body weight continues to increase worldwide primarily because of the increase in body fat. This study analyzes the frequency of massive adiposity at autopsy determined by the ability of the heart to float in a container of 10% formaldehyde (because adipose tissue is lighter than myocardium) and compares certain findings in the patients with floating to those with nonfloating hearts. The hearts studied at necropsy during,a 2-year period (2013 to 2014) at Baylor University Medical Center were carefully “cleaned” and weighed by the same person and tested as to their ability to float in a container of formaldehyde, an indication of severe cardiac adiposity. Of the 146 hearts studied, 76 (52%) floated in a container of formaldehyde and 70 (48%) did not. Comparison of the 76 patients with floating hearts with the 70 with nonfloating hearts showed significant differences in ages (62 +/- 13 vs 58 +/- 14 years). No significant differences between the 2 groups were found in gender, body mass index, frequency of systemic hypertension or diabetes mellitus, either acute or healed myocardial infarction, or whether death was due to a coronary or a noncoronary condition. A weak correlation was found between body mass index and heart weight in both men and women and in both floating and nonfloating hearts. The massive quantity of cardiac adipose tissue (floating heart) appears to have increased enormously in recent decades in the United States.

Roberts, W. C., V. S. Won, A. Vasudevan, J. M. Ko, S. A. Hall and G. V. Gonzalez-Stawinski (2016). “Frequency of massive cardiac adiposity (floating heart) in the native hearts of patients having heart transplantation at a single texas hospital (2013 to 2015) and comparison of various clinical and morphologic variables in the patients with massive versus nonmassive cardiac adiposity.” American Journal of Cardiology 117(8): 1375-1380.

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Body weight continues to increase worldwide due primarily to. the increase in body fat. This study analyzes the frequency of massive adiposity at hearts of patients who underwent heart transplantation (HT) determined by the ability of the heart to float in a container of 10% formaldehyde (because adipose tissue is lighter than myocardium) and compares certain characteristics of those patients with and without floating hearts. The hearts studied at HT during a 3-year period (2013 to 2015) at Baylor University Medical Center were carefully “cleaned” and weighed by the same individual and tested as to their ability to float in a container of formaldehyde, an indication of severe cardiac adiposity. Of the 220 hearts studied, 84 (38%) floated in a container of formaldehyde and 136 (62%) did not. Comparison of the 84 patients with floating hearts to the 136 with nonfloating hearts showed a significant difference in ages, but a nonsignificant difference in gender, body mass index, frequency of systemic hypertension, or diabetes mellitus. The odds of a heart being a floating one was increased in patients with a diagnosis of ischemic cardiomyopathy (un-adjusted odds ratio 2.12, 95% CI 1.21 to 3.70). The frequency of massive cardiac adiposity in the native hearts of patients having HT (38%) is striking and appears to have increased in frequency in the recent decades.

Gomez-Hoyos, J., R. Schroder, I. J. Palmer, M. Reddy, A. Khoury and H. D. Martin (2015). “Iliopsoas tendon insertion footprint with surgical implications in lesser trochanterplasty for treating ischiofemoral impingement: An anatomic study.” Journal of hip preservation surgery 2(4): 385-391.

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The objective of this study was to describe the footprint location of the iliopsoas tendon on the lesser trochanter to clarify the surgical implications of the lesser trochanterplasty for treating ischiofemoral impingement. Ten non-matched, fresh-frozen, cadaveric hemipelvis specimens (average age, 62.4 years; range, 48-84 years; 7 male and 3 female) were included. Registered measures included bony parameters of the lesser trochanter (lesser trochanteric area, distances from the tip to the base in a coordinate system, height and area) and tendinous iliopsoas footprint descriptions (areas and detailed location). The mean height of the lesser trochanter was 13.1 (SD±1.8) mm, with female having a smaller lesser trochanter on average (11.3, SD ± 2.0). A double tendinous footprint was found in 7 (70%) specimens. The average area of the single- and double-footprint was 211.2 mm(2) and 187.9 mm(2), respectively. An anterior cortical area with no tendinous insertion on the anterior aspect of lesser trochanter was present in all specimens and measured 4.9mm (SD±0.6) on average. The mean ratio between the bald anterior wall and the lesser trochanter height was 38% (SD±0.05). The iliopsoas tendon footprint is double (psoas and iliacus) in most cases and is located on the anteromedial tip of the lesser trochanter. A bald anterior wall on the bottom of the lesser trochanter indicates that a partial or total lesser trochanterplasty for increasing the ischiofemoral space without detaching partially or entirely the iliopsoas tendon is improbable.

Gomez-Hoyos, J., R. Schroder, M. Reddy, I. J. Palmer, A. Khoury and H. D. Martin (2015). “Is there a relationship between psoas impingement and increased trochanteric retroversion?” Journal of hip preservation surgery 2(2): 164-169.

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The concept of psoas impingement secondary to a tight or inflamed iliopsoas tendon causing impingement of the anterior labrum during hip extension has been suggested. The purpose of this study was to assess the relationship between the lesser trochanteric version (LTV) in symptomatic patients with psoas impingement as compared with asymptomatic hips. The femoral neck version (FNV) and LTV were evaluated on axial magnetic resonance imaging, as well as the angle between LTV and FNV. Data from 12 symptomatic patients and 250 asymptomatic patients were analysed. The mean, range and standard deviations were calculated. Independent t-tests were used to determine differences between groups. The lesser trochanteric retroversion was significantly increased in patients with psoas impingement as compared with asymptomatic hips (-31.1° SD±6.5 versus -24.2°±11.5, P<0.05). The FNV (9°±8.8 versus 14.1°±10.7, P>0.05) and the angle between FNV and LTV (40.2°±9.7 versus 38.3°±9.6, P>0.05) were not significantly different between groups. In conclusion, the lesser trochanteric retroversion is significantly increased in patients with psoas impingement as compared with asymptomatic hips.