Research Spotlight

Posted December 15th 2017

Male sex may not be associated with worse outcomes in primary all-posterior adult spinal deformity surgery: a multicenter analysis.

Richard Hostin M.D.

Richard Hostin M.D.

Bumpass, D. B., L. G. Lenke, J. L. Gum, C. I. Shaffrey, J. S. Smith, C. P. Ames, S. Bess, B. J. Neuman, E. Klineberg, G. M. Mundis, Jr., F. Schwab, V. Lafage, H. J. Kim, D. C. Burton, K. M. Kebaish, R. Hostin, R. Lafage and M. P. Kelly (2017). “Male sex may not be associated with worse outcomes in primary all-posterior adult spinal deformity surgery: A multicenter analysis.” Neurosurg Focus 43(6): E9.

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OBJECTIVE Adolescent spine deformity studies have shown that male patients require longer surgery and have greater estimated blood loss (EBL) and complications compared with female patients. No studies exist to support this relationship in adult spinal deformity (ASD). The purpose of this study was to investigate associations between sex and complications, deformity correction, and health-related quality of life (HRQOL) in patients with ASD. It was hypothesized that male ASD patients would have greater EBL, longer surgery, and more complications than female ASD patients. METHODS A multicenter ASD cohort was retrospectively queried for patients who underwent primary posterior-only instrumented fusions with a minimum of 5 levels fused. The minimum follow-up was 2 years. Primary outcomes were EBL, operative time, intra-, peri-, and postoperative complications, radiographic correction, and HRQOL outcomes (Oswestry Disability Index, SF-36, and Scoliosis Research Society-22r Questionnaire). Poisson multivariate regression was used to control for age, comorbidities, and levels fused. RESULTS Ninety male and 319 female patients met the inclusion criteria. Male patients had significantly greater mean EBL (2373 ml vs 1829 ml, p = 0.01). The mean operative time, transfusion requirements, and final radiographic measurements did not differ between sexes. Similarly, changes in HRQOL showed no significant differences. Finally, there were no sex differences in the incidence of complications (total, major, or minor) at any time point after controlling for age, body mass index, comorbidities, and levels fused. CONCLUSIONS Despite higher EBL, male ASD patients did not experience more complications or require less deformity correction at the 2-year follow-up. HRQOL scores similarly showed no sex differences. These findings differ from adolescent deformity studies, and surgeons can counsel patients that sex is unlikely to influence the outcomes and complication rates of primary all-posterior ASD surgery.


Posted December 15th 2017

An Interagency Registry for Mechanically Assisted Circulatory Support (INTERMACS) analysis of hospitalization, functional status, and mortality after mechanical circulatory support in adults with congenital heart disease.

Ari M. Cedars M.D.

Ari M. Cedars M.D.

Cedars, A., C. Vanderpluym, D. Koehl, R. Cantor, S. Kutty and J. K. Kirklin (2017). “An interagency registry for mechanically assisted circulatory support (intermacs) analysis of hospitalization, functional status, and mortality after mechanical circulatory support in adults with congenital heart disease.” J Heart Lung Transplant: 2017 Nov [Epub ahead of print].

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BACKGROUND: Adult congenital heart disease (ACHD) prevalence is increasing worldwide, with advanced heart failure (HF) as a leading cause of death. Limited data are available on durable mechanical circulatory support (MCS) in ACHD patients. METHODS: ACHD patients from the Interagency Registry for Mechanically Assisted Circulatory Support (INTERMACS) database were identified and propensity matched with non-ACHD patients using risk factors from the INTERMACS Seventh Annual Report. We compared these groups for the primary outcome of post-MCS mortality. We also investigated adverse event rates, functional status, and health-related quality of life. RESULTS: ACHD (n = 128) and non-ACHD (n = 512) patients were appropriately matched by baseline characteristics. ACHD patients had a longer length of stay at MCS implant (24 vs 19 days, p = 0.006) but similar rates of post-MCS adverse events and hospitalization. There were similar improvements in functional status and health related quality of life post-MCS in both groups. ACHD patients had significantly higher mortality post-MCS exclusively during the first 5 months after implant (p = 0.003) and a lower probability of receiving a transplant (p = 0.003). Risk factors for early mortality were biventricular or total artificial heart device implant and age > 50 years. CONCLUSIONS: ACHD patients experience a higher early mortality after MCS but have similar adverse event rates and similar improvements in functional capacity and quality of life compared with non-ACHD patients. These data support expansion of MCS use in selected ACHD patients.


Posted December 15th 2017

Long-Term Survival in Patients Receiving a Continuous-Flow Left Ventricular Assist Device.

Brian Lima M.D.

Brian Lima M.D.

Gosev, I., M. S. Kiernan, P. Eckman, B. Soleimani, A. Kilic, N. Uriel, J. D. Rich, J. N. Katz, J. Cowger, B. Lima, S. McGurk, M. A. Brisco-Bacik, S. Lee, S. M. Joseph and C. B. Patel (2017). “Long-term survival in patients receiving a continuous-flow left ventricular assist device.” Ann Thorac Surg: 2017 Nov [Epub ahead of print].

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BACKGROUND: Long-term survivors after implantation of left ventricular assist devices (LVADs) are increasing in prevalence. We describe the characteristics and outcomes in patients surviving longer than 4 years on LVAD support. METHODS: We performed a multicenter, retrospective analysis of patients surviving at least 4 years on continuous-flow LVAD (CF-LVAD) support with a HeartMate II at centers participating in the Evolving Mechanical support Research Group. RESULTS: Between 2005 and 2010, 156 long-term survivors were identified with a mean survival of 7.1 years (95% confidence interval: 6.7 to 7.5 years). The mean age was 58.2 +/- 15.2 years and 30.1% were women. Readmission rate was low at 1.1 events per patient per year with the most common reasons leading to readmission being infection (0.10 readmissions per patient per year) and gastrointestinal bleeding (0.07 readmissions per patient per year). Two years after implantation, 97% of patients were either New York Heart Association functional class I or II, with 92% at 4 years. CONCLUSIONS: Patients surviving 4 years on CF-LVAD support can anticipate ongoing long-term survival with sustained improvements in functionality and low rates of rehospitalization.


Posted December 15th 2017

Topiramate and metabolic acidosis: an evolving story.

Michael Emmett, M.D.

Michael Emmett, M.D.

Gupta, S., J. J. Gao, M. Emmett and A. Z. Fenves (2017). “Topiramate and metabolic acidosis: An evolving story.” Hosp Pract (1995) 45(5): 192-195.

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Topiramate is an anticonvulsant that is being increasingly used for a number of different off-label indications. Its inhibition of carbonic anhydrase isoenzymes can lead to metabolic acidosis, elevated urine pH, reduced urine citrate, and hypercalciuria, thereby creating a milieu that is ripe for calcium phosphate stone formation. In this review, we describe a case of topiramate-induced metabolic acidosis. We review the frequency of metabolic acidosis among children and adults, as well as the mechanism of hyperchloremic metabolic acidosis and renal tubular acidosis in topiramate users. Finally, we describe the long-term effects of topiramate-induced metabolic acidosis, including nephrolithiasis, nephrocalcinosis, and bone degradation. Patients who are prescribed topiramate should be carefully monitored for metabolic derangements, and they may benefit from alkali supplementation, or in extreme cases, discontinuation of the drug altogether.


Posted December 15th 2017

Potassium Homeostasis in Health and Disease: A Scientific Workshop Cosponsored by the National Kidney Foundation and the American Society of Hypertension.

Peter McCullough M.D.

Peter McCullough M.D.

Kovesdy, C. P., L. J. Appel, M. E. Grams, L. Gutekunst, P. A. McCullough, B. F. Palmer, B. Pitt, D. A. Sica and R. R. Townsend (2017). “Potassium homeostasis in health and disease: A scientific workshop cosponsored by the national kidney foundation and the american society of hypertension.” Am J Kidney Dis 70(6): 844-858.

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While much emphasis, and some controversy, centers on recommendations for sodium intake, there has been considerably less interest in recommendations for dietary potassium intake, in both the general population and patients with medical conditions, particularly acute and chronic kidney disease. Physiology literature and cohort studies have noted that the relative balance in sodium and potassium intakes is an important determinant of many of the sodium-related outcomes. A noteworthy characteristic of potassium in clinical medicine is the extreme concern shared by many practitioners when confronted by a patient with hyperkalemia. Fear of this often asymptomatic finding limits enthusiasm for recommending potassium intake and often limits the use of renin-angiotensin-aldosterone system blockers in patients with heart failure and chronic kidney diseases. New agents for managing hyperkalemia may alter the long-term management of heart failure and the hypertension, proteinuria, and further function loss in chronic kidney diseases. In this jointly sponsored effort between the American Society of Hypertension and the National Kidney Foundation, 3 panels of researchers and practitioners from various disciplines discussed and summarized current understanding of the role of potassium in health and disease, focusing on cardiovascular, nutritional, and kidney considerations associated with both hypo- and hyperkalemia.