Baylor Heart and Vascular Institute

Piccini, J. P., K. Stromberg, K. P. Jackson, V. Laager, G. Z. Duray, M. El-Chami, C. R. Ellis, J. Hummel, D. R. Jones, R. C. Kowal, C. Narasimhan, R. Omar, P. Ritter, P. R. Roberts, K. Soejima, S. Zhang and D. Reynolds (2017). “Long-term outcomes in leadless micra transcatheter pacemakers with elevated thresholds at implantation: Results from the micra transcatheter pacing system global clinical trial.” Heart Rhythm 14(5): 685-691.

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BACKGROUND: Device repositioning during Micra leadless pacemaker implantation may be required to achieve optimal pacing thresholds. OBJECTIVE: The purpose of this study was to describe the natural history of acute elevated Micra vs traditional transvenous lead thresholds. METHODS: Micra study VVI patients with threshold data (at 0.24 ms) at implant (n = 711) were compared with Capture study patients with de novo transvenous leads at 0.4 ms (n = 538). In both cohorts, high thresholds were defined as >1.0 V and very high as >1.5 V. Change in pacing threshold (0-6 months) with high (1.0 to 1.5 V) thresholds were compared using the Wilcoxon signed-rank test. RESULTS: Of the 711 Micra patients, 83 (11.7%) had an implant threshold of >1.0 V at 0.24 ms. Of the 538 Capture patients, 50 (9.3%) had an implant threshold of >1.0 V at 0.40 ms. There were no significant differences in patient characteristics between those with and without an implant threshold of >1.0 V, with the exception of left ventricular ejection fraction in the Capture cohort (high vs low thresholds, 53% vs 58%; P = .011). Patients with an implant threshold of >1.0 V decreased significantly (P < .001) in both cohorts. Micra patients with high and very high thresholds decreased significantly (P < .01) by 1 month, with 87% and 85% having 6-month thresholds lower than the implant value. However, when the capture threshold at implant was >2 V, only 18.2% had a threshold of 2 V. CONCLUSIONS: Pacing thresholds in most Micra patients with elevated thresholds decrease after implant. Micra device repositioning may not be necessary if the pacing threshold is

Roberts, W. C., P. A. Grayburn, J. M. Guileyardo and R. C. Stoler (2017). “Full development of consequences of congenital pulmonic stenosis in eighty-four years.” Am J Cardiol 119(8): 1284-1287.

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Described herein is an 84-year-old woman, the oldest reported, with severe pulmonic stenosis who underwent a highly successful pulmonic valvotomy at age 77 and highly unsuccessfully attempted percutaneous pulmonic valve implantation at age 84. During the 84 years she developed nearly all clinical and morphologic consequences of pulmonic stenosis, including heavy calcification of the pulmonic valve, heavy calcification of the tricuspid valve annulus, severe right ventricular wall thickening without ventricular cavity dilation, aneurysm of the pulmonary truck, multiple focal ventricular wall scars without narrowing of the epicardial coronary arteries, wall thickening and luminal narrowing of the intramural coronary arteries, and extremely low 12-lead QRS electrocardiographic voltage.

El Chami, M., R. C. Kowal, K. Soejima, P. Ritter, G. Z. Duray, P. Neuzil, L. Mont, A. Kypta, V. Sagi, J. H. Hudnall, K. Stromberg and D. Reynolds (2017). “Impact of operator experience and training strategy on procedural outcomes with leadless pacing: Insights from the micra transcatheter pacing study.” Pacing Clin Electrophysiol: Apr [Epub ahead of print].

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BACKGROUND: Leadless pacemaker systems have been designed to avoid the need for a pocket and transvenous lead. However, delivery of this therapy requires a new catheter-based procedure. This study evaluates the role of operator experience and different training strategies on procedural outcomes. METHODS: A total of 726 patients underwent implant attempt with the Micra transcatheter pacing system (TPS) by 94 operators trained in a teaching laboratory using a simulator, cadaver, and large animal models (lab training) or locally at the hospital with simulator/demo model and proctorship (hospital training). Procedure success, procedure duration, fluoroscopy time, and safety outcomes were compared between training methods and experience (implant case number). RESULTS: The Micra TPS procedure was successful in 99.2% of attempts and did not differ between the 55 operators trained in the lab setting and the 39 operators trained locally at the hospital (P = 0.189). Implant case number was also not a determinant of procedural success (P = 0.456). Each operator performed between 1 and 55 procedures. Procedure time and fluoroscopy duration decreased by 2.3% (P = 0.002) and 3.2% (P<0.001) compared to the previous case. Major complication rate and pericardial effusion rate were not associated with case number (P = 0.755 and P = 0.620, respectively). There were no differences in the safety outcomes by training method. CONCLUSIONS: Among a large group of operators, implantation success was high regardless of experience. While procedure duration and fluoroscopy times decreased with implant number, complications were low and not associated with case number. Procedure and safety outcomes were similar between distinct training methodologies.

Carey, S. A., K. Bass, G. Saracino, C. A. East, J. Felius, P. A. Grayburn, R. C. Vallabhan and S. A. Hall (2017). “Probability of accurate heart failure diagnosis and the implications for hospital readmissions.” Am J Cardiol 119(7): 1041-1046.

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Heart failure (HF) is a complex syndrome with inherent diagnostic challenges. We studied the scope of possibly inaccurately documented HF in a large health care system among patients assigned a primary diagnosis of HF at discharge. Through a retrospective record review and a classification schema developed from published guidelines, we assessed the probability of the documented HF diagnosis being accurate and determined factors associated with HF-related and non-HF-related hospital readmissions. An arbitration committee of 3 experts reviewed a subset of records to corroborate the results. We assigned a low probability of accurate diagnosis to 133 (19%) of the 712 patients. A subset of patients were also reviewed by an expert panel, which concluded that 13% to 35% of patients probably did not have HF (inter-rater agreement, kappa = 0.35). Low-probability HF was predictive of being readmitted more frequently for non-HF causes (p = 0.018), as well as documented arrhythmias (p = 0.023), and age >60 years (p = 0.006). Documented sleep apnea (p = 0.035), percutaneous coronary intervention (p = 0.006), non-white race (p = 0.047), and B-type natriuretic peptide >400 pg/ml (p = 0.007) were determined to be predictive of HF readmissions in this cohort. In conclusion, approximately 1 in 5 patients documented to have HF were found to have a low probability of actually having it. Moreover, the determination of low-probability HF was twice as likely to result in readmission for non-HF causes and, thus, should be considered a determinant for all-cause readmissions in this population.

VanderPluym, C. J., A. Cedars, P. Eghtesady, B. G. Maxwell, J. M. Gelow, L. J. Burchill, S. Maltais, D. A. Koehl, R. S. Cantor and E. D. Blume (2017). “Outcomes following implantation of mechanical circulatory support in adults with congenital heart disease: An analysis of the Interagency Registry for Mechanically Assisted Circulatory Support (INTERMACS).” J Heart Lung Transplant: 2017 Mar [Epub ahead of print].

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BACKGROUND: Adults with congenital heart disease represent an expanding and unique population of patients with heart failure (HF) in whom the use of mechanical circulatory support (MCS) has not been characterized. We sought to describe overall use, patient characteristics, and outcomes of MCS in adult congenital heart disease (ACHD). METHODS: All patients entered into the Interagency Registry for Mechanically Assisted Circulatory Support (INTERMACS) between June 23, 2006, and December 31, 2015, were included. Patients with ACHD were identified using pre-operative data and stratified by ventricular morphology. Mortality was compared between ACHD and non-ACHD patients, and multivariate analysis was performed to identify predictors of death after device implantation. RESULTS: Of 16,182 patients, 126 with ACHD stratified as follows: systemic morphologic left ventricle (n = 63), systemic morphologic right ventricle (n = 45), and single ventricle (n = 17). ACHD patients were younger (42 years +/- 14 vs 56 years +/- 13; p < 0.0001) and were more likely to undergo device implantation as bridge to transplant (45% vs 29%; p < 0.0001). A higher proportion of ACHD patients had biventricular assist device (BiVAD)/total artificial heart (TAH) support compared with non-ACHD patients (21% vs 7%; p < 0.0001). More ACHD patients on BiVAD/TAH support were INTERMACS profile 1 compared with patients on systemic left ventricular assist device (LVAD) support (35% vs 15%; p = 0.002). ACHD and non-ACHD patients with LVADs had similar survival; survival was worse for patients on BIVAD/TAH support. BiVAD/TAH support was the only variable independently associated with mortality (early phase hazard ratio 4.4; 95% confidence interval, 1.8-11.1; p = 0.001). For ACHD patients receiving MCS, ventricular morphology was not associated with mortality. CONCLUSIONS: ACHD patients with LVADs have survival similar to non-ACHD patients. Mortality is higher for patients requiring BiVAD/TAH support, potentially owing to higher INTERMACS profile. These outcomes suggest a promising role for LVAD support in ACHD patients as part of the armamentarium of therapies for advanced HF.