Cardiology

Grayburn, P. A. and Y. Chandrashekhar (2019). “Imaging Challenges in Tricuspid Regurgitation and Right Ventricular Failure.” JACC Cardiovasc Imaging 12(4): 768-770.

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In clinical practice, it is considerably easier to treat left ventricular (LV) heart failure than right ventricular (RV) heart failure. A number of medical therapies have been shown to improve symptoms and survival in LV failure. In addition, cardiac resynchronization and revascularization in appropriately selected patients may improve LV systolic function. Recently, the use of transcatheter edge-to-edge mitral valve repair has been shown to reduce heart failure hospitalization, mortality, and clinical status in a selected group of patients with persistent severe mitral regurgitation (MR) after optimization of medical therapy. Unfortunately, there are few data demonstrating that treatment of RV failure results in improved symptoms or survival. Diuresis is the mainstay of treatment but is used mainly to palliate symptoms. RV failure may respond to therapies targeted at left-sided heart disease or pulmonary hypertension (PH) in some but not all circumstances. RV failure is less well understood, but current thinking suggests it most often is the result of LV failure, as pulmonary venous congestion is transmitted backward to the RV. An unfavorable septal anatomy and dys-synchrony also influence RV function, possibly to a lesser extent. It can also occur secondary to pulmonary arterial hypertension in the setting of chronic pulmonary disease, congenital heart disease, or various pulmonary vascular diseases. As pulmonary artery systolic pressure (PASP) increases, the RV may respond by dilating with or without concentric hypertrophy, which may protect the RV by mitigating wall stress. RV dilation often causes tricuspid regurgitation (TR) or, conversely, may be caused by TR. There is a complex interplay among RV dilation/dysfunction, PH, and TR, but is less well understood than similar interactions in the left heart. Tricuspid valve disease remains a challenging yet growing need, but a wealth of data are starting to come in to clarify therapeutic needs. This issue of iJACC continues where we left off last month and brings more papers addressing right-sided heart function and various aspects of TR. (Excerpt from text, p. 768; no abstract available.)

Grayburn, P. A. (2019). “The Challenge of Assessing Residual Mitral Regurgitation During MitraClip Procedures: Is 3-Dimensional Vena Contracta Area the Answer?” JACC Cardiovasc Interv 12(6): 592-594.

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Transcatheter mitral valve repair with the MitraClip device has developed into a robust clinical tool for treatment of selected patients with severe mitral regurgitation (MR) in whom mitral valve anatomy is suitable for the device. MitraClip is approved in the United States for patients with primary degenerative MR who are considered prohibitive risk for surgery by an experienced heart team including a surgeon skilled in the art of mitral valve repair. In Europe and other countries, MitraClip is approved for both primary and secondary (functional) MR. Two recent randomized clinical trials showed apparently conflicting results with MitraClip in secondary MR. However, the differences in the 2 trials are likely caused by patient selection, with markedly improved outcomes in the setting of a disproportionately larger severity of MR relative to left ventricular (LV) volumes after optimizing medical therapy for heart failure. Several studies have shown that persistence of moderately severe or severe (3þ or 4þ) MR after the procedure is associated with considerably higher 1-year mortality, such that reduction of MR to moderate or less is paramount. Unfortunately, grading of MR severity in the procedural setting is often difficult and always subjective, partly because of the favorable effects of anesthesia on MR severity, the presence of the Mitra-Clips, and the difficulty balancing the need for further reduction in MR with additional clips versus the risk of iatrogenic mitral stenosis. There is a need for more accurate, precise, and reproducible markers of MR severity. (Excerpt from text, p. 592; no abstract available.)

Edgerton, J. R. (2019). “Surgical Ablation of Atrial Fibrillation in Patients with Tachycardia-Induced Cardiomyopathy (Commentary).” Ann Thorac Surg. Apr 2. [Epub ahead of print].

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In this issue of The Annals of Thoracic Surgery, the Washington University group reports the results of surgical ablation of atrial fibrillation in 34 patients with tachycardia induced cardiomyopathy (TIC) defined as left ventricular ejection fraction (LVEF) <41% and absent another etiology. Excluding one death, 33 patients were available for follow-up and 27 of these had an evaluable echo at about 12 months. At 12 months 94% of patients were free of atrial tachyarrhythmias with/without antiarrhythmic drugs (AADs). Mean LVEF improved from 32% to 55%. Of 11 pts in NYHA Class III/IV, 8 improved to Class I/II. These changes reached statistical significance. It is important to note that LV function improved in all patients and it improved to >55% in 19/27 patients. The prognostic significance of the presence of fibrosis (inhibits recovery of function), as reported in the CAMERA-MRI study and reiterated in this report, should be stressed. In patient selection, it is important to differentiate between TIC and a dilated cardiomyopathy with secondary atrial fibrillation (AF). The former will not be helped by performing a Maze and the latter will. To differentiate, the authors perform a cardiac MRI to assess for myocardial viability and the degree of left ventricular fibrosis by late gadolinium enhancement (LGE). On multivariate analysis, only the absence of LGE was found to predict LVEF normalization. Any presence of fibrosis rules the patient out as a candidate for surgical ablation. If there is any other abnormality on cardiac MRI, or a high index of suspicion, endomyocardial biopsies are performed. Thus, a pre-op MRI will help the clinician in deciding whether to operate for TIC. Although the numbers of patients are small, documenting these findings is very significant. It would be easy for a reader to dismiss this paper as a small retrospective series of little significance. This would be a grave error. Yes, the numbers are small, but few groups have adequate volume to accumulate this many patients and most lack the investigatory rigor to document the post-op course in such detail. Additionally, very few groups have pre-op MRIs on these patients. As the authors point out, current guideline statements on the treatment of TIC, “include only non-surgical rhythm control strategies.” This is the true significance of this paper. Based on the findings documented here, a Class IIa, LOE B-NR is justified for surgical ablation of AF in patients with TIC who are undergoing cardiac surgery for another reason or have failed AADs and catheter ablation. Future guideline committees need to consider this work when revising current guidelines. (Excerpt from text, p. 1 of article-in-press.)

Dewan, P., R. Rorth, P. S. Jhund, J. P. Ferreira, F. Zannad, L. Shen, L. Kober, W. T. Abraham, A. S. Desai, K. Dickstein, M. Packer, J. L. Rouleau, S. D. Solomon, K. Swedberg, M. R. Zile and J. J. V. McMurray (2019). “Income Inequality and Outcomes in Heart Failure: A Global Between-Country Analysis.” JACC Heart Fail 7(4): 336-346.

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OBJECTIVES: This study examined the relationship between income inequality and heart failure outcomes. BACKGROUND: The income inequality hypothesis postulates that population health is influenced by income distribution within a society, with greater inequality associated with worse outcomes. METHODS: This study analyzed heart failure outcomes in 2 large trials conducted in 54 countries. Countries were divided by tertiles of Gini coefficients (where 0% represented absolute income equality and 100% represented absolute income inequality), and heart failure outcomes were adjusted for standard prognostic variables, country per capita income, education index, hospital bed density, and health worker density. RESULTS: Of the 15,126 patients studied, 5,320 patients lived in Gini coefficient tertile 1 countries (coefficient: <33%), 6,124 patients lived in tertile 2 countries (33% to 41%), and 3,772 patients lived in tertile 3 countries (>41%). Patients in tertile 3 were younger than tertile 1 patients, were more often women, and had less comorbidity and several indicators of less severe heart failure, yet the tertile 3-to-1 hazard ratios (HRs) for the primary composite outcome of cardiovascular death or heart failure hospitalization were 1.57 (95% confidence interval [CI]: 1.38 to 1.79) and 1.48 for all-cause death (95% CI: 1.29 to 1.71) after adjustment for recognized prognostic variables. After additional adjustments were made for per capita income, education index, hospital bed density, and health worker density, these HRs were 1.46 (95% CI: 1.25 to 1.70) and 1.30 (95% CI: 1.10 to 1.53), respectively. CONCLUSIONS: Greater income inequality was associated with worse heart failure outcomes, with an impact similar to those of major comorbidities. Better understanding of the societal and personal bases of these findings may suggest approaches to improve heart failure outcomes.

Dearani, J. A., T. K. Rosengart, M. B. Marshall, M. J. Mack, D. R. Jones, R. L. Prager and R. J. Cerfolio (2019). “Incorporating Innovation and New Technology Into Cardiothoracic Surgery.” Ann Thorac Surg 107(4): 1267-1274.

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The appropriate implementation of new technology, root cause analysis of “imperfect” outcomes, and the continuous reappraisal of postgraduate training are needed to improve the care of tomorrow’s patients. Healthcare delivery remains one of the most expensive sectors in the United States, and the application of new and expensive technology that is necessary for the advancement of this complex specialty must be aligned with providing the best care for our patients. There are a several pathways to innovation: One is partnering with industry and the other is the investigational laboratory. Innovation and the funding thereof come from both the public and private sector. Most new trials that are likely to impact cardiothoracic surgery are industry-sponsored trials to meet the requirements necessary for regulatory approval. Cost considerations are paramount when considering integration of innovative technology and treatments into a clinical cardiothoracic surgical practice. The value of any new innovation is determined by the quality divided by the cost, and lean initiatives maximize this equation. The importance and implications of conflict of interest have been a concern for physicians, particularly when new technology or procedures are incorporated into clinical practice, and full disclosures by medical professionals and others involved are essential. Our societies and associations provide a platform for presentation and peer-reviewed discussion of new procedures, innovations, and trials and provide a venue for the sharing of knowledge on the highest quality patient care through education and research.