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LV torsion may predict outcomes after mitral valve surgery
In patients with nonischemic, chronic, severe secondary mitral regurgitation and a narrow QRS, left ventricular torsion may predict post-mitral surgery outcomes, according to data published in JACC: Basic to Translational Science.
“These findings show that lost [LV] torsion and previously administered cardiac resynchronization therapy appear to be markers of poor survival after mitral surgery in patients with [nonischemic, chronic, severe secondary mitral regurgitation],” Yuichi Notomi, MD, from the division of cardiovascular imaging, department of cardiology at the Hayama Heart Center in Kanagawa, Japan, said in a press release. “We also found that reverse remodeling was only observed in patients with preserved [LV] torsion, demonstrating that lost [LV] torsion and wide QRS were markers of no reverse remodeling viability.”
Mitral valve surgery
Notomi and colleagues analyzed data from 50 patients with nonischemic, chronic secondary mitral regurgitation who received mitral valve surgery at the Hayama Heart Center from September 2006 to August 2012. Patients were divided into three groups: preserved LV torsion, lost LV torsion and patients with a wide QRS measurement who received CRT (wideQRS/CRT). The wideQRS/CRT group was then subdivided into patients who received CRT before mitral valve surgery and patients who were given CRT at the time of mitral valve surgery. Median follow-up was 2.5 years.
According to the results, 12 patients died of congestive HF, one received ventricular assist device implantation, four patients died suddenly and two died of noncardiac causes. Two-year survival rates also were different between the three groups (preserved LV group, 87%; lost LV group, 22%; wideQRS/CRT group, 50%; log-rank P < .0002).
End-systolic LV torsion was higher in the preserved LV group (8.2° 3.6) than in the lost LV (–1.4° 5) and WideQRS/CRT group (3.2° 6.1), but no significant difference was observed between the lost LV and wideQRS/CRT groups.
In addition, congestive HF was more common in the lost LV group (67%) than in the preserved LV group (9%). Reverse remodeling was only observed in the preserved LV group.
Timing of CRT also appears to be important. Patients who received CRT before mitral surgery had worse 2-year survival than those whose procedure was performed during the mitral valve surgery.
“Mechanistically, this study suggests that the loss of torsion in patients with [HF] may reflect irreversible structural damage to the heart, which would prevent the heart from recovering after corrective surgery,” Douglas L. Mann, MD, FACC, editor-in-chief of JACC: Basic to Translational Science, professor of medicine and chief of cardiology at Washington University School of Medicine, St. Louis, and a member of the Cardiology Today Editorial Board, said in the release. “If correct, this will have much broader implications than improvement after mitral valve surgery since it may predict which patients with [HF] may get better on medications.”
Douglas L. Mann
Specificity still lacking
In an accompanying editorial, Daniel Burkhoff, MD, PhD, of the Cardiovascular Research Foundation and Columbia University, and Julius Guccione, PhD, of the University of California, San Francisco, wrote: “Despite its limitations, the study highlights the potential utility of torsion in prognostication. This parameter, along with other parameters, such as regional and global measurements of strain, have become more readily available through the use of 2- and 3-dimensional ultrasound speckle tracking. Torsion and longitudinal strain have been touted as measures of myocardial dysfunction that may be more sensitive to the presence of pathology than ejection fraction.”
Burkhoff and Guccione also wrote that because torsion and longitudinal strain may be influenced by other factors, they “lack specificity as diagnostic tools.”
They concluded that “The fact that torsion increases with severe aortic stenosis (rather than decreases) highlights potential complexities inherent in the interpretation of this parameter. Thus, such parameters may be most useful for detecting the presence of some pathology, and potentially for tracking natural history of disease progression or responses to therapy.” – by Tracey Romero
Disclosure: The researchers and Mann report no relevant financial disclosures. Burkhoff reports consulting for BackBeat Medical, CardiacImplants Inc., Corvia Medical, HeartWare International, Impulse Dynamics and Sensible Medical. Guccione reports consulting for Dassault Systems.