Comparison of Early Surgery Versus Conventional Treatment in Asymptomatic Severe Mitral Regurgitation

Changes in left ventricular morphology and function after mitral valve surgery

Degenerative mitral valve disease is the leading cause of mitral regurgitation in North America. Surgical intervention has hinged on the symptoms and ventricular changes that develop as compensatory ventricular remodeling occurs. In the present study, we sought to characterize the temporal response of left ventricular (LV) morphology and function to mitral valve surgery for degenerative disease and to identify the preoperative factors that influence reverse remodeling. From 1986 to 2007, 2,778 patients with isolated degenerative mitral valve disease underwent valve repair (n = 2,607 [94%]) or replacement (n = 171 [6%]) and had ≥1 postoperative transthoracic echocardiogram; 5,336 transthoracic echocardiograms were available for analysis. Multivariate longitudinal repeated-measures analysis was performed to identify the factors associated with reverse remodeling. The LV dimensions decreased in the first year after surgery (end-diastolic from 5.7 ± 0.80 to 4.9 ± 1.4 cm; end-systolic from 3.4 ± 0.71 to 3.1 ± 1.4 cm). The LV mass index decreased from 139 ± 44 to 112 ± 73 g/m(2). The reduction in LV hypertrophy was less pronounced in patients with greater preoperative left heart enlargement (p <0.0001) and a greater preoperative LV mass (p <0.0001). The postoperative LV ejection fraction initially decreased from 58 ± 7.0% to 53 ± 20%, increased slightly during the first postoperative year, and was negatively influenced by preoperative heart failure symptoms (p <0.0001) and a lower preoperative LV ejection fraction (p <0.0001). The risk-adjusted response of LV morphology and function to valve repair and replacement was similar (p >0.2). In conclusion, a positive response toward normalization of LV morphology and function after mitral valve surgery is greatest in the first year. The best response occurs when surgery is performed before left heart dilation, LV hypertrophy, or LV dysfunction develop.

The importance of exercise echocardiography for clinical decision making in primary mitral regurgitation

Primary mitral regurgitation is generally an insidious disease with late onset of symptoms. Current European and American guidelines recommend surgery in severe primary mitral regurgitation when symptoms, overt left ventricular dysfunction, pulmonary hypertension or atrial fibrillation, occur. However, recent large studies reported an improved outcome in asymptomatic patients with severe mitral regurgitation referred for early mitral valve repair despite the risk of operative mortality or mitral valve replacement. Moreover, primary mitral regurgitation appears to have an important dynamic character in up to one-third of patients. This article provides an overview of the incremental evidence of the ability of exercise echocardiography to assess the functional repercussions of mitral regurgitation and the identification of high-risk patients who might benefit from early referral for surgery.

Echocardiographic Predictors of Adverse Short-term Outcomes after Heart Surgery in Patients with Mitral Regurgitation and Pulmonary Hypertension

<p><b>Background:</b> Pulmonary hypertension (PH) is a frequent occurrence and a negative prognostic indicator in patients with mitral regurgitation. Preoperative PH causes higher early and late mortality rates after heart surgery, adverse cardiac events, and postoperative systolic dysfunction in the left ventricle (LV).</p><p><b>Methods:</b> The research consisted of a retrospective study of a group of 171 consecutive patients with mitral regurgitation and preoperative PH who had undergone mitral valve surgery between January 2008 and October 2011. The PH diagnosis was based on echocardiographic evidence (systolic pulmonary artery pressure [sPAP] >35 mm Hg). The echocardiographic examination included assessment of the following: LV volume, LV ejection fraction (LVEF), sPAP, right ventricular end-diastolic diameter, right atrium area indexed to the body surface area, the ratio of the pulmonary acceleration time to the pulmonary ejection time (PAT/PET), tricuspid annular plane systolic excursion (TAPSE), determination of the severity of the associated tricuspid regurgitation, and presence of pericardial fluid. Surgical procedures consisted of mitral valve repair in 55% of the cases and mitral valve replacement in the remaining 45%. Concomitant coronary artery bypass grafting (CABG) surgery was carried out in 52 patients (30.41%), and De Vega tricuspid annuloplasty was performed in 29 patients (16.95%). The primary end point was perioperative mortality. The secondary end points included the following: pericardial, pleural, hepatic, or renal complications; the need for a new surgical procedure; postoperative mechanical ventilation >24 hours; length of stay in the intensive care unit; duration of postoperative inotropic support; need for an intra-aortic balloon pump; and need for pulmonary vasodilator drugs.</p><p><b>Results:</b> The mortality rate was 2.34%. In the univariate analysis, the clinical and echocardiographic parameters associated with mortality were preoperative New York Heart Association (NYHA) class IV, the PAT/PET ratio, TAPSE, the indexed area of the right atrium, and concomitant CABG surgery. In the multivariate analysis, the indexed area of the right atrium and concomitant CABG surgery remained statistically significant. The multivariate analysis also showed the indexed area of the right atrium, LVEF, presence of pericardial fluid, preoperative NYHA class, and concomitant CABG surgery as statistically significant for the secondary end point. The receiver operating characteristic (ROC) curves identified an sPAP value >65 mm Hg to have the highest specificity and sensitivity for the risk of perioperative death in mitral regurgitation patients (area under the ROC curve [AUC], 0.782; <i>P</i> < .001) and identified an sPAP value of 60 mm Hg as the secondary end point (AUC, 0.82; <i>P</i> < .001). Severe PH (sPAP >60 mm Hg) is associated with a significant increase in the mortality rate; a longer stay in the intensive care unit; a mechanical ventilation duration >24 hours; lengthy inotropic support; renal, hepatic, and pericardial complications; and a need for endothelin receptor antagonists, phosphodiesterase type 5 inhibitors, and/or prostanoids, both in the general group and in patients with preserved systolic functioning of the left ventricle.</p><p><b>Conclusions:</b> PH is a strong short-term negative prognostic factor for patients with mitral regurgitation. The surgical procedure should be performed in the early stages of PH. Echocardiographic examination has useful, simple, and reproducible tools for classifying operative risks. An ischemic etiology and a need for concomitant CABG surgery are additional risk factors for patients with mitral regurgitation and PH.</p>

Watchful waiting for severe mitral regurgitation

Watchful waiting is an established treatment strategy for asymptomatic patients with severe organic mitral regurgitation. It is based on indications for surgery that are based on current European Society of Cardiology and American Heart Association/American College of Cardiology guideline recommendations, which are defined by symptom onset, impairment of left ventricular function, and left ventricular enlargement. Excellent outcome is achieved when patients are periodically followed with clinical and echocardiographic examinations and when surgery is performed in expert centers. The strategy is based on the recognition of mitral regurgitation at an early symptomatic stage, avoiding a delayed referral of these patients. There is an ongoing debate about whether surgery should be performed in asymptomatic patients with preserved ventricular function. Ultimately, decision-making needs to be individualized and to take individual patient-related factors and local resources (including the natural history of the disease, the risk of surgery, and the likelihood of successful mitral valve repair) into consideration to obtain an optimal outcome with medical and surgical management.

Magnetic resonance imaging with 3-dimensional analysis of left ventricular remodeling in isolated mitral regurgitation: implications beyond dimensions

BACKGROUND

Although surgery is indicated in patients with mitral regurgitation (MR) when left ventricular (LV) end-systolic (LVES) dimension is >40 mm, LV ejection fraction may decrease after mitral valve surgery. We hypothesize that significant LV remodeling before surgery is not reflected by standard echocardiographic parameters measured at the base of the heart.

METHODS AND RESULTS

Ninety-four patients (age, 54 ± 11 years; 38% female) with degenerative isolated MR underwent cine magnetic resonance imaging with tissue tagging and 3-dimensional analysis. In 51 control subjects (age, 44 ± 14 years; 53% female), the relation between LVES volume (LVESV) and LVES dimension was quadratic, whereas in 94 MR patients, this relation was cubic, indicating a greater increase in LVESV per LVES dimension among MR patients. Moreover, magnetic resonance imaging LVESV from summated serial short-axis slices was significantly greater than LVESV assessed with the Bullet formula in MR patients, attributed to a more spherical remodeling distal to the tips of the papillary muscles (P<0.001). Thirty-five patients underwent mitral valve repair per current guideline recommendations. LV ejection fraction decreased from 61 ± 7% to 54 ± 8% (P<0.0001) and maximum shortening decreased significantly below normal at 1 year postoperatively (P<0.0001). Despite normalization of LV stroke volume and LV end-diastolic volume/mass ratio, there was a persistent significant increase in distal LVES 3-dimensional radius/wall thickness ratio and LVESV index after surgery.

CONCLUSIONS

Despite apparently preserved LVES dimension, MR patients demonstrate significant spherical mid to apical LVES remodeling that contributes to higher LVESV than predicted by standard geometry-based calculations. Decreased LV strain after surgery suggests that a volumetric analysis of LV remodeling and function may be preferred to evaluate disease progression in isolated MR.

Mitral Valve Prolapse With Mid-Late Systolic Mitral Regurgitation

Background—

Mitral regurgitation (MR) of mitral valve prolapse predominates in late systole but may be holosystolic or purely mid-late systolic, but the impact of MR timing on MR left ventricular and left atrial consequences and outcome is unknown. Whether effective regurgitant orifice (ERO) by the flow convergence method is similarly linked to outcome in mid-late systolic MR and holosystolic MR is uncertain.

Methods and Results—

We comprehensively and prospectively quantified MR in 111 patients with mitral valve prolapse and mid-late systolic MR and matched them to 90 patients with mitral valve prolapse and holosystolic MR for age, gender, atrial fibrillation, ejection fraction, and ERO (flow convergence). Mid-late systolic MR versus holosystolic MR groups were well matched, including for comorbidity, blood pressure, and heart rate (all P >0.10). Mid-late systolic MR versus holosystolic MR caused similar color jet area, midsystolic regurgitant flow, and peak velocity ( P >0.40). Despite identical ERO (0.25±0.15 versus 0.25±0.15 cm 2 ; P =0.53), the shorter duration of mid-late systolic MR (233±56 versus 426±50 ms; P <0.0001) yielded lower regurgitant volume (24.8±13.4 versus 48.6±25.6 mL; P <0.0001). MR consequences, systolic pulmonary pressure, and left ventricular and left atrial volume index (all P <0.001) were more benign in mid-late systolic MR versus holosystolic MR. Under medical management, fewer cardiac events (5 years: 15.8±4.6% versus 40.4±6.1%; P <0.0001) occurred in mid-late systolic MR versus holosystolic MR, requiring less mitral surgery. Multivariable analysis confirmed the independent association of mid-late systolic MR with benign consequences and outcomes (all P <0.01). Absolute ERO was not linked to outcome, in contrast to regurgitant volume.

Conclusions—

MR of mitral valve prolapse that is purely mid-late systolic causes more benign consequences and outcomes than holosystolic MR. Assessment may be misleading because jet area and ERO by flow convergence appear similar to those of holosystolic MR. However, shorter MR yields lower regurgitant volume, consequences, and benign outcomes. Instantaneous ERO by flow convergence should be interpreted in context, and in mid-late systolic MR, regurgitant volume provides information more reflective of MR severity. Therefore, for clinical management and surgical referral, clinicians should carefully take into account the timing and consequences of MR.

Mitral valve replacement using mechanical prostheses in children: early and long-term outcomes

Compared with mitral repair, mitral valve replacement is an uncommon procedure in children due to associated high mortality and morbidity rates. The present study investigated early and late outcomes after MVR with mechanical prostheses in children at our institution. Between January 1994 and December 2009, 19 children underwent MVR. Mean patient age was 7.6 ± 5.5 years (range 3 months-16 years), and mean body weight was 23.7 ± 15.1 kg (range 5.0-58.1 kg). Mean prosthesis size was 25.8 ± 4.2 mm (range 19-31 mm). There were no operative or late mortalities. Three patients showed decreased left-ventricular function before surgery, and one of them underwent successful heart transplantation due to progressive LV dysfunction at 10 months after MVR. The proportion of patients with freedom from reoperation at 10 years was 94.7 ± 5%. There were no major thromboembolic or bleeding episodes. Although the small number of patients in our study was a limitation, MVR in children was found to result in excellent early and long-term outcomes. It appears that MVR could be considered in children before LV dysfunction develops.

Percutaneous versus surgical revascularization in patients with ischemic mitral regurgitation

BACKGROUND

The proper way of revascularization remains controversial in patients with ischemic mitral regurgitation (IMR). We sought to compare the long-term results of percutaneous coronary intervention (PCI) and surgical revascularization in IMR.

METHODS AND RESULTS

From 1996 to 2008, 185 consecutive patients (132 men; age, 63 ± 9 years) with significant IMR underwent PCI (PCI group) (n=66) or coronary artery bypass graft surgery (OP group) (n=119). In the OP group, 68 (57%) patients also underwent concomitant mitral annuloplasty. Significant IMR was defined as functional MR occurring >1 week after myocardial infarction with an effective regurgitant orifice area ≥ 0.2 cm(2). During a median follow-up of 54 months, there were 2 operative mortalities, 26 cardiac deaths, and 11 heart failure hospitalizations in the OP group and 22 cardiac deaths and 10 heart failure hospitalizations in the PCI group. The survival and cardiac mortality rates were not significantly different between the 2 groups, but event-free survival rates were significantly higher in the OP group. For the 45 propensity score-matched pairs, the risk of cardiac events was significantly lower in the OP group than in the PCI group (hazard ratio, 0.499; 95% CI, 0.251 to 0.990; P=0.043). Compared with patients who underwent coronary artery bypass graft surgery alone, event-free survival rates were significantly higher in those who underwent additional mitral annuloplasty.

CONCLUSIONS

Compared with PCI, surgical revascularization is associated with an improved long-term event-free survival, and concomitant mitral annuloplasty should be considered in patients with significant IMR.

Oxidative stress and myocardial remodeling in chronic mitral regurgitation

Mechanisms of left ventricular (LV) dysfunction in isolated mitral regurgitation (MR) are not well understood. Vasodilator therapy in other forms of LV dysfunction reduces LV wall stress and improves LV function; however, studies in isolated MR show no beneficial effect on LV remodeling using vasodilator drugs or renin-angiotensin system blockade. Therefore, the search for new therapies that improve LV remodeling and function in isolated MR is clinically significant. Recent work in the authors' laboratory has demonstrated increased oxidants from a number of sources including the enzyme xanthine oxidase (XO) in the LV of patients with isolated MR. In addition to being a major source of reactive oxygen species, XO is linked to bioenergetic dysfunction because its substrates derive from adenosine triphosphate catabolism. Correspondingly, there was also evidence of aggregates of small mitochondria in cardiomyocytes, which is generally considered a response to bioenergetic deficit in cells. Future studies are required to determine whether XO and persistent oxidative stress are causative in maladaptive LV remodeling and offer potential therapeutic targets in ameliorating LV damage in patients with isolated MR.

Surgery for asymptomatic degenerative aortic and mitral valve disease

Degenerative valvular heart disease, the most common form of valve disease in the Western world, can lead to aortic stenosis (AS) or mitral regurgitation (MR). In current guidelines for the management of patients with degenerative valvular disease, surgical intervention is recommended at the onset of symptoms or in the presence of left ventricular systolic impairment. Whether surgery is appropriate for asymptomatic patients remains a controversial issue. We argue the case for early pre-emptive intervention in selected, asymptomatic individuals with AS or MR, drawing on contemporary perioperative data, predictors of disease progression, and studies of the natural history of degenerative valvular heart disease.

Progress in the treatment of severe mitral regurgitation

Organic mitral regurgitation (MR) is prevalent in the general population. Disease progression, involving potentially irreversible left ventricular dysfunction, implies a poor prognosis for patients who do not receive appropriate treatment. Immediate rescue surgery is indicated in those with severe MR in whom subclinical left ventricular dysfunction is suggested by echocardiographic measurements or the presence of symptoms, however minor. Patients whose symptomatology is unclear should be evaluated by exercise testing. Not all forms of severe organic MR are the same: the presence of risk factors in patients with severe asymptomatic MR and preserved ventricular function indicates a suboptimal prognosis over the medium-to-long term and should prompt early mitral repair if there is a low surgical risk and the probability of a successful repair is >90-95%. The patient should be referred to a specialized surgical center if necessary. Appropriate training of surgeons in mitral repair is essential. Ischemic MR carries a worse prognosis and the risk of surgery is higher. Consequently, treatment decisions must be patient-specific and take into account the possibility of repair, the risk of surgery, and the need for concomitant surgical revascularization. New percutaneous approaches to mitral repair are being developed for selected patient groups.

Impact of early surgery on embolic events in patients with infective endocarditis

BACKGROUND

Surgical indications to prevent systemic embolism in infective endocarditis (IE) remain controversial. We sought to compare clinical outcomes of early surgery with conventional treatment in IE patients with embolic indications only.

METHODS AND RESULTS

From 1998 to 2006, we prospectively enrolled 132 consecutive patients (86 men; age, 49±17 years) with definite IE. Patients were included if they had a left-sided native valve endocarditis with vegetation. The choice of early surgery or conventional treatment was at the discretion of attending physician. Early surgery was performed on 64 patients (OP group) within 7 days of diagnosis, and conventional management was chosen for 68 patients (CONV group). The OP group had larger vegetations and a higher percentage of patients with severe valvular disease (88% versus 62%, P=0.001). During initial hospitalization, there were no embolic events and 2 in-hospital deaths in the OP group and 14 embolic events and 2 in-hospital deaths in the CONV group. During a median follow-up of 1402 days, there were 2 cardiovascular deaths, 2 embolic events, and 1 recurrence of IE in the CONV group, and 1 cardiovascular death and 2 embolic events in the OP group. The 5-year event-free survival rate was significantly higher in the OP group (93±3%) than in the CONV group (73±5%, P=0.0016). For 44 propensity score-matched pairs, the OP group had a lower event rate (hazard ratio, 0.18; P=0.007).

CONCLUSIONS

Compared with conventional treatment, an early surgery strategy is associated with improved clinical outcomes by effectively decreasing systemic embolism in patients with IE.

A propensity score-adjusted retrospective comparison of early and mid-term results of mitral valve repair versus replacement in octogenarians

AIMS

Feasibility and efficacy of mitral repair in the elderly remain controversial. This study aims to compare outcomes of mitral repair and replacement in octogenarians.

METHODS AND RESULTS

We compared the outcomes of 322 consecutive octogenarian patients (mean age 82.6 ± 2.2 years) who underwent mitral repair (n = 227, 70%) or replacement (n = 95, 30%) at Mount Sinai Medical Center and Leipzig Herzzentrum between 1998 and 2008 using propensity score adjustment and univariate and multivariate analyses. Patients undergoing aortic valve replacement were excluded. Coronary bypass was performed in 47.5% (n = 153), and 31.1% (n = 100) required tricuspid repair. Propensity score adjustment yielded comparable groups. Thirty-day mortality in patients undergoing primary elective mitral repair for degenerative disease was 5.1% (2/39). Overall 90-day mortality was 18.9% (43/227) for repair compared with 31.6% (30/95) for replacement (P = 0.014). Pre-discharge echocardiography revealed less than moderate residual regurgitation in 99% of patients (231/232). Adjusted 1-, 3-, and 5-year survival for patients undergoing mitral repair was 71 ± 3, 61 ± 4, and 59 ± 4%, respectively, compared with 56 ± 5, 50 ± 6, and 45 ± 6% for patients undergoing mitral replacement (P = 0.046). Multivariate analysis demonstrated emergency surgery, previous myocardial infarction, concomitant coronary artery bypass surgery, and mitral replacement to be strong independent predictors of early mortality; mitral valve replacement was an independent predictor of reduced survival in degenerative patients.

CONCLUSION

Elective mitral repair can be performed with low operative mortality and good long-term outcomes in selected octogenarians with degenerative mitral disease, and is associated with better long-term survival than mitral replacement. The survival benefit associated with surgery for non-degenerative disease is more questionable.

Degenerative mitral valve regurgitation: best practice revolution

Degenerative mitral valve disease often leads to leaflet prolapse due to chordal elongation or rupture, and resulting in mitral valve regurgitation. Guideline referral for surgical intervention centres primarily on symptoms and ventricular dysfunction. The recommended treatment for degenerative mitral valve disease is mitral valve reconstruction, as opposed to valve replacement with a bioprosthetic or mechanical valve, because valve repair is associated with improved event free survival. Recent studies have documented a significant number of patients are not referred in a timely fashion according to established guidelines, and when they are subjected to surgery, an alarming number of patients continue to undergo mitral valve replacement. The debate around appropriate timing of intervention for asymptomatic severe mitral valve regurgitation has put additional emphasis on targeted surgeon referral and the need to ensure a very high rate of mitral valve repair, particularly in the non-elderly population. Current clinical practice remains suboptimal for many patients, and this review explores the need for a ‘best practice revolution’ in the field of degenerative mitral valve regurgitation.

MitraClip catheter-based mitral valve repair system

The ongoing evolution of transcatheter valve technology is impressive. Mitral valve regurgitation is the most common type of heart valve insufficiency and mitral valve surgery is, next to aortic valve surgery, the second leading valvular surgical procedure in the western world. However, there is a large patient population suffering from mitral valve regurgitation that is currently not treated with heart surgery because of significant morbidity and mortality risks. This large underserved patient population could benefit from a less invasive treatment. The MitraClip system (Abbott Vascular, Menlo Park, CA, USA) is the first commercially available medical technology providing a catheter-based nonsurgical repair alternative for patients suffering from mitral valve regurgitation and has the greatest clinical experience compared with other alternative devices. The device is currently in late-stage clinical trials in the USA and has received the CE mark.

Early surgery versus conventional treatment in asymptomatic very severe aortic stenosis

BACKGROUND

The optimal timing of surgical intervention remains controversial in asymptomatic patients with very severe aortic stenosis. We therefore compared the long-term results of early surgery and a conventional treatment strategy.

METHODS AND RESULTS

From 1996 to 2006, we prospectively included a total of 197 consecutive asymptomatic patients (99 men; age, 63+/-12 years) with very severe aortic stenosis. Patients were excluded if they had angina, syncope, exertional dyspnea, ejection fraction <0.50, significant mitral valve disease, or age >85 years. Very severe aortic stenosis was defined as a critical stenosis in the aortic valve area < or =0.75 cm(2) accompanied by a peak aortic jet velocity > or =4.5 m/s or a mean transaortic pressure gradient > or =50 mm Hg on Doppler echocardiography. The primary end point was defined as the composite of operative mortality and cardiac death during follow-up. Early surgery was performed on 102 patients, and a conventional treatment strategy was used for 95 patients. There were no significant differences between the 2 groups in terms of age, gender, European System for Cardiac Operative Risk Evaluation score, or ejection fraction. During a median follow-up of 1501 days, the operated group had no operative mortalities, no cardiac deaths, and 3 noncardiac deaths; the conventional treatment group had 18 cardiac and 10 noncardiac deaths. The estimated actuarial 6-year cardiac and all-cause mortality rates were 0% and 2+/-1% in the operated group and 24+/-5% and 32+/-6% in the conventional treatment group, respectively (P<0.001), and for 57 propensity score-matched pairs, the risk of all-cause mortality was significantly lower in the operated group than in the conventional treatment group (hazard ratio, 0.135; 95% confidence interval, 0.030 to 0.597; P=0.008).

CONCLUSIONS

Compared with the conventional treatment strategy, early surgery in patients with very severe aortic stenosis is associated with an improved long-term survival by decreasing cardiac mortality. Early surgery is therefore a therapeutic option to further improve clinical outcomes in asymptomatic patients with very severe aortic stenosis and low operative risk.

The emerging role of exercise testing and stress echocardiography in valvular heart disease

Exercise testing has an established role in the evaluation of patients with valvular heart disease and can aid clinical decision making. Because symptoms may develop slowly and indolently in chronic valve diseases and are often not recognized by patients and their physicians, the symptomatic, blood pressure, and electrocardiographic responses to exercise can help identify patients who would benefit from early valve repair or replacement. In addition, stress echocardiography has emerged as an important component of stress testing in patients with valvular heart disease, with relevant established and potential applications. Stress echocardiography has the advantages of its wide availability, low cost, and versatility for the assessment of disease severity. The versatile applications of stress echocardiography can be tailored to the individual patient with aortic or mitral valve disease, both before and after valve replacement or repair. Hence, exercise-induced changes in valve hemodynamics, ventricular function, and pulmonary artery pressure, together with exercise capacity and symptomatic responses to exercise, provide the clinician with diagnostic and prognostic information that can contribute to subsequent clinical decisions. Nevertheless, there is a lack of convincing evidence that the results of stress echocardiography lead to clinical decisions that result in better outcomes, and therefore large-scale prospective randomized studies focusing on patient outcomes are needed in the future.