Mitral valve surgery in patients with ischemic and nonischemic dilated cardiomyopathy

Parameters of the mitral apparatus in patients with ischemic and nonischemic dilated cardiomyopathy

The mitral valve apparatus is a complex structure consisting of several coordinating components: the annulus, two leaflets, the chordae tendineae, and the papillary muscles. Due to the intricate interplay between the mitral valve and the left ventricle, a disease of the latter may influence the normal function of the former. As a consequence, valve insufficiency may arise despite the absence of organic valve disease. This is designated as functional or secondary mitral regurgitation, and it arises from a series of distortions to the valve components. This narrative review describes the normal anatomy and the pathophysiology behind the mitral valve changes in ischemic and non-ischemic dilated cardiomyopathies. It also explains the value of a complete multiparametric assessment of this structure. Not only must an assessment include quantitative measures of regurgitation, but also various anatomical parameters from the mitral apparatus and left ventricle, since they carry prognostic value and are predictors of mitral valve repair success and durability.

Pulmonary Complications After Cardiac Surgery

Over the past two decades there has been a steady evolution in the practice of adult cardiac surgery with the introduction of “off-pump” surgery. However, respiratory complications remain a leading cause of postcardiac surgical morbidity and can prolong hospital stays and increase costs. The high incidence of pulmonary complications is in part due to the disruption of normal ventilatory function that is inherent to surgery in the thoracic region. Furthermore, patients undergoing such surgery often have underlying illnesses such as intrinsic lung disease (e.g., chronic obstructive pulmonary disease) and pulmonary dysfunction secondary to cardiac disease (e.g., congestive heart failure) that increase their susceptibility to postoperative respiratory problems. Given that many patients undergoing cardiac surgery are thus susceptiple to pulmonary complications, it is remarkable that more patients do not suffer from them during and after cardiac surgery. This is to a large degree because of advances in anesthetic, surgical and critical care that, for example, have reduced the physiological insults of surgery (e.g., better myocardial preservation techniques) and streamlined care in the immediate postoperative period (e.g., early extubation). Moreover, the development of minimally invasive surgery and nonbypass techniques are further evidence of the attempts at reducing the homeostatic disruptions of cardiac surgery. This review examines the available information on the incidences, consequences, and treatments of postcardiac surgery respiratory complications.

Does modern medicine increase life-expectancy: Quest for the Moon Rabbit?

The search for elixir of immortality has yielded mixed results. While some of the interventions like percutaneous coronary interventions and coronary artery bypass grafting have been a huge disappointment at least as far as prolongation of life is concerned, their absolute benefit is meager and that too in very sick patients. Cardiac specific drugs like statins and aspirin have fared slightly better, being useful in patients with manifest coronary artery disease, particularly in sicker populations although even their usefulness in primary prevention is rather low. The only strategies of proven benefit in primary/primordial prevention are pursuing a healthy life-style and its modification when appropriate, like cessation of smoking, weight reduction, increasing physical activity, eating a healthy diet and bringing blood pressure, serum cholesterol, and blood glucose under control.

An image of mitral valve repair

Mitral regurgitation is a severe problem of the mitral valve mechanism caused by many factors, including ischemic and nonischemic cardiomyopathy, inflammation, degeneration and others. Regardless of the cause of valve dysfunction, many changes in surgical approach have been undertaken. The pioneering work of Carpentier led to the era of mitral valve reconstruction a few decades ago. Understanding the different techniques applied in several pathoanatomic settings is of major interest. This review summarizes the indications and results of this specific surgical procedure in the setting of ventricular dysfunction by different causes.

Flow assessment through four heart valves simultaneously using 3-dimensional 3-directional velocity-encoded magnetic resonance imaging with retrospective valve tracking in healthy volunteers and patients with valvular regurgitation

OBJECTIVES

To validate 3-dimensional (3D) 3-directional velocity-encoded (VE) magnetic resonance imaging (MRI) for flow assessment through all 4 heart valves simultaneously with retrospective valve-tracking during off-line analysis in healthy volunteers and in patients with valvular regurgitation.

MATERIAL AND METHODS

Three-dimensional 3-directional VE MRI was performed in 22 healthy volunteers and in 29 patients with ischemic cardiomyopathy who were suspected of valvular regurgitation and net flow volumes through the 4 heart valves were compared. Furthermore, the analysis was repeated for each valve in 10 healthy volunteers and in 10 regurgitant valves to assess intra- and interobserver agreement for assessment of respectively net flow volumes and regurgitation fraction.

RESULTS

In healthy volunteers, the average net flow volume through the mitral valve, tricuspid valve, aortic valve, and pulmonary valve was 85 +/- 20 mL, 85 +/- 21 mL, 83 +/- 19 mL, 82 +/- 21 mL, respectively. Strong correlations between net flow volumes through the 4 heart valves were observed (intraclass correlation coefficients [ICC] 0.93-0.95) and the coefficient of variance (CV) was small (6%-9%). The repeated analysis by the same observer and by a second observer yielded good agreement for measurement of net flow volumes (ICC: 0.93-0.99 and CV: 3%-7%). Strong correlations between the net flow volumes through the 4 heart valves were also observed in the patients with valvular regurgitation (ICC: 0.85-0.95 and CV: 7%-18%). The average net flow volume through the mitral valve, tricuspid valve, aortic valve, and pulmonary valve was 63 +/- 20 mL, 63 +/- 20 mL, 63 +/- 20 mL, 63 +/- 20 mL, respectively. Furthermore, the intra- and interobserver agreement for assessment of regurgitation fraction was good (ICC: 0.86 and 0.85, CV: 12% and 13%).

CONCLUSIONS

Flow assessment using 3D 3-directional VE MR with retrospective valve-tracking during off-line analysis enables accurate quantification of net flow volumes through 4 heart valves within a single acquisition in healthy volunteers and in patients with valvular regurgitation.

The efficacy of mitral valve surgery in children with dilated cardiomyopathy and severe mitral regurgitation

Severe mitral regurgitation predicts poor outcomes in adults with left ventricular dysfunction. Frequently, adult patients now undergo initial mitral valve surgery instead of heart transplant. Pediatric data are limited. This study evaluates the efficacy of mitral valve surgery for severe mitral regurgitation in children with dilated cardiomyopathy. This is a single-institution experience in seven children (range, 0.5-10.9 years) with severe mitral regurgitation and dilated cardiomyopathy who underwent mitral valve surgery between January 1988 and February 2005, with follow-up to January 2006. Children with dilated cardiomyopathy had a depressed fractional shortening preoperatively (24.4% +/- 6.1%) that remained depressed (22.9% +/- 7.6%) 1.3 +/- 1.2 years after surgery (p = 0.50). Left ventricular end-diastolic (6.5 +/- 1.5 to 4.8 +/- 1.8 z-scores, p < 0.01) and end-systolic (6.8 +/- 1.5 to 5.5 +/- 2.1 z-scores, p < 0.05) dimensions improved. Hospitalization frequency had a median decrease of 6.0 hospitalizations per year (p < 0.02). Three patients were transplanted 0.2, 2.4, and 3.5 years after surgery. There was no perioperative mortality. Mitral valve surgery in children with dilated cardiomyopathy was performed safely and improved symptoms, stabilizing ventricular dysfunction in most patients. Mitral valve surgery should be considered prior to heart transplant in children with dilated cardiomyopathy and severe mitral regurgitation.

Moderate-to-severe ischemic mitral regurgitation and multivessel coronary artery disease: Impact of different treatment on survival and rehospitalization

BACKGROUND

The outcome of moderate-to-severe ischemic mitral regurgitation with multivessel coronary artery disease is still debated. We analysed the effect of different treatments, i.e. medical therapy (MT), coronary artery by-pass grafting (CABG) alone and CABG with mitral valve surgery (MVS), on the survival and rehospitalization of these patients.

METHODS

Between 1990 and 2002, we identified 111 consecutive patients, aged 73+/-8 years, with chronic moderate-to-severe mitral regurgitation and multivessel coronary artery disease at cardiac catheterization, in absence of primary valve disease. Twenty-two patients were treated by MT, 50 by CABG and 39 by CABG+MVS. Overall, the median clinical and echocardiographic follow-ups were 34.9 and 14.6 months, respectively.

RESULTS

Groups differed significantly (p < 0.03) for left ventricular end-diastolic volume index (MT 153+/-54, CABG 125+/-35, CABG + MVS 129+/-38, ml/m2), ejection fraction (MT 35+/-14, CABG 38+/-13, CABG + MVS 50+/-14, %) and mammary artery graft use (CABG 60, CABG + MVS 74, %). While in-hospital mortality was higher in surgical patients (MT 13.6, CABG 18, CABG + MVS 17.9, %, p=0.09), 7-years mortality showed a trend in favour of CABG + MVS compared to other groups (MT 100, CABG 57, CABG + MVS 29, %, p = 0.1). After adjusting for baseline differences, CABG alone or with MVS had a 57% (HR 0.43, p = 0.005) and 53% (HR 0.47, p = 0.02) risk reduction of combined cardiac death and rehospitalization rate compared to MT. However, only CABG + MVS independently predicted mortality (risk reduction 65%, HR 0.35, p = 0.027).

CONCLUSIONS

In moderate-to-severe ischemic mitral regurgitation and multivessel coronary artery disease, surgery reduced total cardiac events but only a concomitant MVS significantly improved survival.

A heart failure specialist's perspective on cardiac surgery for heart failure

Aside from cardiac transplantation, ventricular assist devices, and the total artificial heart, cardiac surgery now also plays a major role in the overall management of the heart failure patient. For patients with heart failure, cardiac surgery has steadily moved from being a predominant rescue procedure (eg, aneursymectomy, rupture repair, transplantation) to surgical interventions that can prevent or delay the progression of cardiac dysfunction and failure; these operations now include coronary artery bypass surgery, ventricular restoration, and valvular repair/replacement. This article discusses the role and impact of these specific surgical interventions in the setting of ventricular dysfunction and heart failure.