Effect of mitral valve surgery on exercise capacity, ventricular ejection fraction and neurohormonal activation in patients with severe mitral regurgitation

Mitral repair with leaflet preservation versus leaflet resection and ventricular reverse remodeling from a randomized trial

OBJECTIVES

In the Canadian Mitral Research Alliance (CAMRA) Trial CardioLink-2 leaflet resection versus preservation techniques for posterior leaflet prolapse was investigated and no difference was shown in their effect on mean mitral gradient at peak exercise at 12 months postoperatively. The purpose of this subanalysis was to evaluate the effect of the 2 strategies on left ventricular (LV) reverse remodeling after repair.

METHODS

A total of 104 patients were randomized to either a leaflet resection or leaflet preservation strategy. Echocardiograms, performed at baseline (preoperative), predischarge, and 12 months postoperatively, were analyzed in a blinded fashion at a core laboratory.

RESULTS

All patients underwent successful mitral repair. At discharge, 3 patients showed moderate mitral regurgitation, whereas the remainder showed mild or less regurgitation. Compared with the baseline echocardiogram, the indexed end diastolic volume was reduced at the discharge echocardiogram (P < .0001) and was further reduced at the 12-month echocardiogram (P = .01). In contrast, the indexed end systolic volume did not significantly change from baseline assessed at the predischarge echocardiogram (P = .32) but improved at 12 months postoperatively (P < .0001), resulting in a corresponding improvement in ejection fraction at 12 months (P < .0001). The type of mitral repair strategy had no significant effect on LV reverse remodeling trends.

CONCLUSIONS

The mitral repair strategies used did not influence postoperative LV reverse remodeling, which occurred in stages. Although LV end diastolic dimensions recovered before discharge, improvements in LV end systolic dimension were evident 12 months after repair.

Outcome of mitral valve repair or replacement for non-ischemic mitral regurgitation: a systematic review and meta-analysis

Background

Mitral regurgitation (MR) is a rather common valvular heart disease. The aim of this systematic review and meta-analysis was to compare the outcomes, and complications of mitral valve (MV) replacement with surgical MV repair of non-ischemic MR (NIMR)

Methods

MEDLINE, EMBASE, and the Cochrane Central Register of Controlled Trials were searched until October, 2020. Studies were eligible for inclusion if they included patients with MR and reported early (30-day or in-hospital) or late all-cause mortality. For each study, data on all-cause mortality and incidence of reoperation and operative complications in both groups were used to generate odds ratios (ORs) or hazard ratios (HRs). This study is registered with PROSPERO, CRD42018089608.

Results

The literature search yielded 4834 studies, of which 20 studies, including a total of 21,898 patients with NIMR, were included. The pooled analysis showed that lower age, less female inclusion and incident of hypertension, significantly higher rates of diabetes and atrial fibrillation in the MV replacement group than MV repair group. No significant differences in the rates of pre-operative left ventricle ejection fraction (LVEF) and heart failure were observed between groups. The number of patients in the MV repair group was lower than in the MV replacement group. We found that there were significantly increased risks of mortality associated with replacement of MR. Moreover, the rate of re-operation and post-operative MR in the MV repair group was lower than in the MV replacement group.

Conclusions

In patients with NIMR, MV repair achieves higher survival and leads to fewer complications than surgical MV replacement. In light of these results, we suggest that MV repair surgery should be a priority for NIMR patients.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13019-021-01563-2.

Early exercise training feasibility after aortic valve repair: A multicentre prospective French survey on behalf of the Aortic Valve repair International Registry (AVIATOR)

BACKGROUND

Standardization of aortic valve repair by the external ring annuloplasty approach is an alternative to valve replacement to avoid prosthetic valve-related events. Although the benefit of exercise training to improve postoperative exercise tolerance has been demonstrated in many conditions after cardiac surgery, it has never been described after aortic valve repair.

OBJECTIVES

To evaluate the feasibility of an early exercise training programme after aortic valve repair.

METHODS

Consecutive patients were prospectively included in 13 postoperative centres. Patients underwent an exercise training programme for approximately 3-5 weeks. Transthoracic echocardiography and a cardiopulmonary exercise test were performed before and after the exercise training programme.

RESULTS

Fifty patients (mean±standard deviation [SD] age: 50±13 years) were included a mean of 13.6±12.0 days after aortic valve repair. The preoperative degree of aortic insufficiency was moderate to severe in 35 patients (70%) and the aortic valve was bicuspid in 24 patients (48%). Valve-sparing root replacement and isolated aortic valve repair (including 10% supracoronary aorta replacement) were performed in 64% and 36% of patients, respectively. We found no aortic insufficiency occurrence or worsening and no adverse clinical events after the exercise training programme. Mean left ventricular ejection fraction increased significantly (from 54%±8% to 57%±9%; P=0.0007). Mean peak oxygen consumption and first ventilatory threshold increased from 17.0±5.3 to 22.5±7.8mL/kg/min (32% increase) and from 12.0±3.9 to 14.3±5.2mL/kg/min (19% increase), respectively (both P<0.05).

CONCLUSION

Exercise training early after aortic valve repair is safe and seems to significantly improve exercise capacity.

High prevalence of physical inactivity after heart valve surgery and its association with long-term mortality: A nationwide cohort study

AIMS

Physical activity (PA) and systematic efforts, such as cardiac rehabilitation, are recommended by several national guidelines for those who have received heart valve surgery. However, only a few studies have demonstrated real-world situations, such as changes in the PA level after heart valve surgery, and their effects on long-term outcomes. We designed this study to investigate the changes in PA after heart valve surgery and their associations with mortality using nationwide representative data.

METHODS

This study was performed using the Korean National Health Insurance Service database. We included patients who received heart valve surgery from 2009 to 2015 and underwent regular health checkups before and after surgery. Subjects were grouped according to their PA level before and after the surgery. Information on all-cause mortality was obtained until 31 December 2016, with a maximum follow-up period of 5 years.

RESULTS

Of the 6587 subjects, 3258 (49.5%) were physically inactive after surgery. Among patients who were physically active (n = 3070), 1196 (39.0%) became inactive after surgery. The postoperative 'inactive' group showed higher mortality than the 'active' group (hazard ratio (HR): 1.41, 95% confidence interval (CI): 1.08-1.83). The 'inactive/inactive' group showed the highest risk of mortality (HR: 1.69, 95% CI: 1.19-2.40) compared with the 'active/active' group.

CONCLUSIONS

Insufficient PA level after heart valve surgery is associated with higher risk of mortality. However, maintaining sufficient PA after heart valve surgery may be challenging for many patients. Therefore, systematic efforts, such as cardiac rehabilitation, should be considered in those who received heart valve surgery.

[Rehabilitation of valvular patient]

Valvular disease is the second indication of cardiac rehabilitation (CR) after coronary artery disease. Patients suffering valvular disease are addressed to CR after valvular repair, and are usually old. Valvular replacement are the most frequent, and more and more patients being treated by TAVI are addressed to CR. CR takes place on two phases: From the seventh (day 7) to the fifteenth (day 15) day: management of complications, respiratory physio, and help to autonomy if necessary. From the fifteenth day (day 15): rehabilitation to exercise after an exercise stress test with or without MVO₂ measurement. Because the patients are taking anticoagulants and are at risk of endocarditis, therapeutic education takes an important place during the stage. CR of patients suffering valvular disease has demonstrated its usefulness with: An increase of exercise capacity in all kind of valvular disease; A reduction of left ventricular hypertrophy in patients with aortic valve stenosis. No serious complication was observed in all studies regarding CR in patients with valvular disease.

Predicting exercise capacity recovery immediately after mitral valve surgery

BACKGROUND

This study presents the exercise capacity of postmitral valve surgery patients and determines predictors capable of affecting recovery.

METHODS

A total of 302 patients with mitral regurgitation who had undergone mitral surgery at the Heart Center in Taiwan from 1 August 2013 to 31 December 2015 were included in the present study. Data related to specific predictors of operative outcome were collected, including demographic data, intraoperative factors, exercise tolerance, echocardiogram data, concurrent cardiovascular disease history, comorbidities, lifestyle risk factors, and surgery types. Postoperative exercise capacity was presented as peak oxygen consumption (VO₂ ; mL of O ₂ /kg/min) determined by exercise tests 3 weeks after surgery. Subjects were separated into two groups: a preserved recovery (peak VO ₂  ≥ 65% of predicted VO _2max ) group and a poor recovery group (peak VO ₂  < 65% of predicted VO _2max ). Preliminary univariate analysis was performed to test for possible relationships between predictive variables and exercise capacity. An analysis of all items shown to be significantly different between the two groups was then subjected to multivariate logistic regression analysis. Detected differences with P < .05 were considered significant.

RESULTS

Among the 302 patients sampled, female sex (odds ratio [OR], 2.65; 95% confidence interval [95% CI], 1.58-4.47), obesity (OR, 0.26; 95% CI, 0.10-0.64), sedentary lifestyle (OR, 0.47; 95% CI, 0.28-0.79), and high preoperative New York Heart Association Functional Classification level (OR, 0.52; 95% CI, 0.31-0.87) were significant predictors of poor exercise capacity.

CONCLUSIONS

Without complicated clinical procedures, physicians and medical teams could easily use these items of information to screen the exercise capacity of mitral valve surgery patients and prepare a suitable after surgery plan if needed or request a consultation as early as possible.

Left ventricular remodelling in chronic primary mitral regurgitation: implications for medical therapy

Surgical repair or replacement of the mitral valve is currently the only recommended therapy for severe primary mitral regurgitation. The chronic elevation of wall stress caused by the resulting volume overload leads to structural remodelling of the muscular, vascular and extracellular matrix components of the myocardium. These changes are initially compensatory but in the long term have detrimental effects, which ultimately result in heart failure. Understanding the changes that occur in the myocardium due to volume overload at the molecular and cellular level may lead to medical interventions, which potentially could delay or prevent the adverse left ventricular remodelling associated with primary mitral regurgitation. The pathophysiological changes involved in left ventricular remodelling in response to chronic primary mitral regurgitation and the evidence for potential medical therapy, in particular beta-adrenergic blockers, are the focus of this review.

The Right Heart-Pulmonary Circulation Unit and Left Heart Valve Disease

Valvular heart disease (VHD) is frequently accompanied by pulmonary hypertension (PH). In asymptomatic patients, PH is rare, although the exact prevalence is unknown and mainly stems from the severity of the VHD and the presence of diastolic dysfunction. PH can also be depicted during exercise echocardiography. PH either at rest or during exercise is also a powerful determinant of outcome and is independently associated with reduced survival, regardless of the severity of the underlying valvular pathology. Therefore, because PH is a marker of poor prognosis, assessment of PH in VHD is crucial for risk stratification and management of patients with VHD.

Preoperative evaluation before MitraClip®: present and future perspective

Mitral regurgitation (MR) is the second most common heart valve disease worldwide. Currently, the management of MR is based on medical therapy (including biventricular pacing), surgery (mitral valve replacement or repair) and percutaneous therapy. However, in spite of guideline recommendations, 50% of individuals assessed in the Euro Heart Survey were not referred to surgical intervention due to comorbidities or real or perceived high risks for cardiac surgery; thus, in recent years, the focus of research has shifted to the development of percutaneous approaches to treat severe MR in order to restore valve function in a minimally invasive fashion. Among these techniques, the percutaneous mitral valve repair procedure using the MitraClip(®) system (Abbott Vascular, IL, USA) is one of the most promising. Usually, patient selection for MitraClip implantation is based on careful echocardiographic assessment of valve disease; however, although definitive data are lacking, evidence is mounting for a multiparametric approach including the evaluation of the functional status of patients.

Impact of the preoperative risk and the type of surgery on exercise capacity and training after valvular surgery

Information on exercise capacity and training in patients who underwent valvular surgery is scarce. The aim of this study is to evaluate postoperative exercise capacity and functional improvement after exercise training according to the preoperative risk and type of surgery. In this prospective study, 145 patients who underwent aortic valve surgery (AVS) or mitral valve surgery (MVS) and who were referred for cardiac rehabilitation were stratified according to the preoperative risk (European System for Cardiac Operative Risk Evaluation [EuroSCORE]) and type of surgery (sternotomy vs ministernotomy or port access). Exercise capacity was evaluated at the start and end of cardiac rehabilitation. Postoperative exercise capacity and the benefit from exercise training were compared between the groups. Patients with a higher preoperative risk had a worse postoperative exercise capacity, with a lower load, peak VO2, anaerobic threshold and 6-minute walking distance (all p<0.001), and a higher VE/VCO2 slope (p=0.01). In MVS, port access patients performed significantly better at baseline (all p<0.05), but in AVS, ministernotomy patients performed better than sternotomy patients with a concomitant coronary artery bypass graft (p<0.05). Training resulted in an improvement in exercise capacity in each risk group and each type of surgery (all p<0.05). This gain in exercise capacity was comparable for the EuroSCORE risk groups and for the types of surgery, for patients after AVS or MVS. In conclusion, exercise capacity after cardiac surgery is related to the preoperative risk and the type of surgery. Despite these differences in postoperative exercise capacity, a similar benefit from exercise training is obtained, regardless of their preoperative risk or type of surgery.

Importance of preservation of chordal apparatus in mitral valve replacement

Mitral valve replacement often involves disruption of the chordal apparatus with disturbance of the annulo-papillary continuity. This results in significant downgrading of ventricular function. Analyzes various reports to accurately assess the advantages of chordal preservation. This review briefly briefly reviews the surgical techniques. The advantages of chordal preservation are analyzed, with particular emphasis on the technical difficulties and potential complications involved.

Percutaneous Mitral Valve Repair in the Initial EVEREST Cohort

Background—

Percutaneous repair of mitral regurgitation (MR) permits examination of the effect of MR reduction without surgery and cardiopulmonary bypass on left ventricular (LV) dimensions and function. The goal of this analysis was to determine the extent of reverse remodeling at 12 months after successful percutaneous reduction of MR with the MitraClip device.

Methods and Results—

Of 64 patients with 3 and 4+ MR who achieved acute procedural success after treatment with the MitraClip device, 49 patients had moderate or less MR at 12-month follow-up. Their baseline and 12-month echocardiograms were compared between the group with and without LV dysfunction. In patients with persistent MR reduction and pre-existing LV dysfunction, there was a reduction in LV wall stress, reduced LV end-diastolic volume, LV end-systolic volume and increase in LV ejection fraction in contrast to those with normal baseline LV function, who showed reduction in LV end-diastolic volume, LV wall stress, no change in LV end-systolic volume, and a fall in LV ejection fraction.

Conclusions—

Patients with pre-existing LV dysfunction demonstrate reverse remodeling and improved LV ejection fraction after percutaneous mitral valve repair.

Clinical Trial Registration—

URL: http://www.clinicaltrials.gov . Unique identifiers: NCT00209339, NCT00209274.

Right ventricular systolic function in organic mitral regurgitation: impact of biventricular impairment

BACKGROUND

To assess the prevalence, determinants, and prognosis value of right ventricular (RV) ejection fraction (EF) impairment in organic mitral regurgitation.

METHODS AND RESULTS

Two hundred eight patients (62±12 years, 138 males) with chronic organic mitral regurgitation referred to surgery underwent an echocardiography and biventricular radionuclide angiography with regional function assessment. Mean RV EF was 40.4±10.2%, ranging from 10% to 65%. RV EF was severely impaired (≤35%) in 63 patients (30%), and biventricular impairment (left ventricular EF<60% and RV EF≤35%) was found in 34 patients (16%). Pathophysiologic correlates of RV EF were left ventricular septal function (β=0.42, P<0.0001), left ventricular end-diastolic diameter index (β=-0.22, P=0.002), and pulmonary artery systolic pressure (β=-0.14, P=0.047). Mitral effective regurgitant orifice size (n=84) influenced RV EF (β=-0.28, P=0.012). In 68 patients examined after surgery, RV EF increased strongly (27.5±4.3-37.9±7.3, P<0.0001) in patients with depressed RV EF, whereas it did not change in others (P=0.91). RV EF ≤35% impaired 10-year cardiovascular survival (71.6±8.4% versus 89.8±3.7%, P=0.037). Biventricular impairment dramatically reduced 10-year cardiovascular survival (51.9±15.3% versus 90.3±3.2%, P<0.0001; hazard ratio, 5.2; P<0.0001) even after adjustment for known predictors (hazard ratio, 4.6; P=0.004). Biventricular impairment reduced also 10-year overall survival (34.8±13.0% versus 72.6±4.5%, P=0.003; hazard ratio, 2.5; P=0.005) even after adjustment for known predictors (P=0.048).

CONCLUSIONS

In patients with organic mitral regurgitation referred to surgery, RV function impairment is frequent (30%) and depends weakly on pulmonary artery systolic pressure but mainly on left ventricular remodeling and septal function. RV function is a predictor of postoperative cardiovascular survival, whereas biventricular impairment is a powerful predictor of both cardiovascular and overall survival.

Prognostic value of B-type natriuretic peptide in patients with chronic mitral regurgitation undergoing surgery: mid-term follow-up results

OBJECTIVES

The prognostic value of B-type natriuretic peptide (BNP) for surgical outcome in patients with mitral regurgitation (MR) has not been studied. The purpose of this study was to determine the prognostic value of BNP in patients with chronic severe MR, undergoing mitral valve surgery.

METHODS

In total, 117 patients with chronic severe MR undergoing surgery were evaluated from the MR registry of Seoul National University Hospital. Patients were excluded if they had acute MR or acutely decompensated heart failure, and significant renal, pulmonary, coronary or other significant valvular heart disease. The plasma BNP level assay and echocardiographic studies were done before surgery. Study endpoint was a composite of cardiac death and cardiac hospitalization during follow-up.

RESULTS

The median duration of the follow-up was 4.5 years, and the study endpoint was reached in 11 (9.4%) patients. Receiver-operating characteristic curve analysis yielded an optimal cut-off point of 125 pg/ml for BNP that distinguished patients with poor prognosis. Kaplan-Meier survival analysis with the log-rank test and multivariate Cox proportional hazards model showed that patients with BNP ≥125 pg/ml had a worse clinical outcome after surgery (log rank 7.606, P = 0.006; adjusted hazard ratio = 5.536 [95% confidence interval 1.189-25.788], P = 0.029).

CONCLUSIONS

Among patients with chronic severe MR undergoing mitral valve surgery, BNP independently predicts the poor clinical outcome. The BNP measurement should be considered in the risk stratification of these patients.

Association of heart rhythm with exercise capacity after operation for chronic mitral regurgitation

BACKGROUND

Although atrial fibrillation (AF) and decreased exercise capacity are common in chronic mitral regurgitation patients, the relationship between rhythm status and exercise capacity after corrective surgery is largely unknown.

METHODS

Seventy-one patients undergoing repair or replacement of mitral valve for chronic severe mitral regurgitation were examined with preoperative and 6 months' postoperative cardiopulmonary exercise test and two-dimensional echocardiography. Patients were divided into three groups according to preoperative versus postoperative rhythm (sinus/sinus, SS [n=42]; AF/sinus, AS [n=17]; AF/AF, AA group [n=12]).

RESULTS

Preoperative maximal oxygen consumption was lower and ventilatory efficiency was higher in the AS and AA groups compared with the SS group. However, maximal oxygen consumption improved only in the AS group at 6 months' postoperative cardiopulmonary exercise test (24.0±6.9 versus 24.6±6.1 mL·kg(-1)·min(-1) in the SS group, 19.3±5.9 versus 23.2±6.4 mL·kg(-1)·min(-1) in the AS group, 19.8±5.4 versus 18.8±5.1 mL·kg(-1)·min(-1) in the AA group; p=0.016 for maximal oxygen consumption by analysis of covariance) as well as ventilatory efficiency. Echocardiography verified more significant reduction of left atrial volume in the SS and AS groups than in the AA group (172.2±68.0 versus 96.7±31.0 mL in the SS group, 247.5±77.8 versus 129.2±25.7 mL in the AS group, 316.7±210.0 versus 192.0±95.0 mL in the AA group; p=0.001 for left atrial volume by analysis of covariance) as well as pulmonary artery systolic pressure. When analyzed for significant predictors of postoperative maximal oxygen consumption, being in the AS group but not the SS group was a significant positive predictor when compared with the AA group (β=5.475; p=0.006).

CONCLUSIONS

Successful sinus conversion of AF, preferably by maze operation, in patients undergoing surgical correction of chronic severe mitral regurgitation confers improved exercise capacity. Reduction of left atrial volume and pulmonary artery pressure may contribute to this improvement.

Increased oxidative stress and cardiomyocyte myofibrillar degeneration in patients with chronic isolated mitral regurgitation and ejection fraction >60%

OBJECTIVES

This study assessed myocardial damage in patients with chronic isolated mitral regurgitation (MR) and left ventricular ejection fraction (LVEF) >60%.

BACKGROUND

Typically, MR patients have decreased LVEF after mitral valve (MV) repair despite normal pre-operative LVEF.

METHODS

Twenty-seven patients with isolated MR had left ventricular (LV) biopsies taken at time of MV repair. Magnetic resonance imaging with tissue tagging was performed in 40 normal subjects and in MR patients before and 6 months after MV repair.

RESULTS

LVEF (66 +/- 5% to 54 +/- 9%, p < 0.0001) and LV end-diastolic volume index (108 +/- 28 ml/m(2) to 78 +/- 24 ml/m(2), p < 0.0001) decreased, whereas left ventricular end-systolic (LVES) volume index was 60% above normal pre- and post-MV repair (p < 0.05). The LV circumferential and longitudinal strain rates decreased below normal following MV repair (6.38 +/- 1.38 vs. 5.11 +/- 1.28, p = 0.0009, and 7.51 +/- 2.58 vs. 5.31 +/- 1.61, percentage of R to R interval, p < 0.0001), as LVES stress/LVES volume index ratio was depressed at baseline and following MV repair versus normal subjects (0.25 +/- 0.10 and 0.28 +/- 0.05 vs. 0.33 +/- 0.12, p < 0.01). LV biopsies demonstrated cardiomyocyte myofibrillar degeneration versus normal subjects (p = 0.035). Immunostaining and immunoblotting demonstrated increased xanthine oxidase in MR versus normal subjects (p < 0.05). Lipofuscin deposition was increased in cardiomyocytes of MR versus normal subjects (0.62 +/- 0.20 vs. 0.33 +/- 0.11, percentage of area: p < 0.01).

CONCLUSIONS

Decreased LV strain rates and LVES wall stress/LVES volume index following MV repair indicate contractile dysfunction, despite pre-surgical LVEF >60%. Increased oxidative stress could cause myofibrillar degeneration and lipofuscin accumulation resulting in LV contractile dysfunction in MR.

Standards for the use of cardiopulmonary exercise testing for the functional evaluation of cardiac patients: a report from the Exercise Physiology Section of the European Association for Cardiovascular Prevention and Rehabilitation

Cardiopulmonary exercise testing (CPET) is a methodology that has profoundly affected the approach to patients' functional evaluation, linking performance and physiological parameters to the underlying metabolic substratum and providing highly reproducible exercise capacity descriptors. This study provides professionals with an up-to-date review of the rationale sustaining the use of CPET for functional evaluation of cardiac patients in both the clinical and research settings, describing parameters obtainable either from ramp incremental or step constant-power CPET and illustrating the wealth of information obtainable through an experienced use of this powerful tool. The choice of parameters to be measured will depend on the specific goals of functional evaluation in the individual patient, namely, exercise tolerance assessment, training prescription, treatment efficacy evaluation, and/or investigation of exercise-induced adaptations of the oxygen transport/utilization system. The full potentialities of CPET in the clinical and research setting still remain largely underused and strong efforts are recommended to promote a more widespread use of CPET in the functional evaluation of cardiac patients.

Comparison of recovery after mitral valve repair and replacement

OBJECTIVE

We sought to examine the comparative improvement in health status after primary mitral valve repair versus replacement in patients with mitral valve regurgitation in a longitudinal setting.

METHODS

We prospectively followed 267 patients with mitral valve regurgitation who underwent primary mitral valve repair (n = 163) and replacement (n = 104) between January 2002 and January 2005. Health status was evaluated at baseline and 1, 3, and 12 months after surgery with the validated short-form 36 and analyzed using generalized estimating equations with adjustment for propensity scores.

RESULTS

Compared with patients undergoing mitral valve replacement, patients requiring valve repair were younger and more likely to be male. The probability of postsurgical readmission because of cardiac events was low and similar between the two treatment groups. New York Heart Association functional class was significantly improved after both procedures, with better improvement achieved by mitral valve repair (P < .01). For both treatment groups, scores for most of the short-form 36 domains were depressed at 1 month; however, after 3- and 12-month lags, dramatic improvements were achieved in most of the domains. Adjusted changes in the physical component score were similar between the two arms at each follow-up. For the mental component score, patients who underwent repair showed significant improvements compared with patients who underwent replacement at both 3 months (difference: 4.84 points, P = .005) and 12 months (difference: 5.92 points, P < .001).

CONCLUSIONS

Our study suggests that after mitral valve surgery, there is significant improvement in New York Heart Association functional class and health status, especially in patients undergoing mitral valve repair.

[Exercise training in cardiac patients: usefulness of the cardiopulmonary exercise test]

Exercise training is currently including in the treatment of coronary arterial disease patients, in patients with left ventricular dysfunction as well as in patients who underwent cardiac transplantation or cardiac surgery. However methods of prescribing exercise-training programs are difficult to determine and must be adapted for each patient Exercise test with gas analysis through the determination of anaerobic threshold may help to understand the physiopathological mechanism related to exercise limitation in these patients. Exercise test may help to precise exercise intensity during cardiac rehabilitation and may assess the benefits on exercise tolerance.

Cardiopulmonary Exercise Testing Determination of Functional Capacity in Mitral Regurgitation

OBJECTIVES

This study was designed to evaluate prevalence, determinants, and clinical outcome implications of reduced functional capacity (FC) in patients with organic mitral regurgitation (MR).

BACKGROUND

Evaluation of FC by exercise testing is rarely performed in MR because little is known about the clinical determinants and outcome implications of FC.

METHODS

Cardiopulmonary exercise testing (CPET) was prospectively performed in 134 asymptomatic patients with organic MR to assess FC (peak oxygen consumption [VO2]) simultaneously to Doppler-echocardiographic quantitation of MR (effective regurgitant orifice [ERO]) and left ventricular (LV) systolic and diastolic function.

RESULTS

Peak VO2 was 26 +/- 6 ml/kg/min (96 +/- 16% of age-predicted), but varied widely (57% to 145% of predicted) and was markedly reduced (< or =84% of predicted) in 19% of patients. Although ERO of MR was univariately associated with reduced FC (26 vs. 9% with ERO > or =40 vs. <40 mm2), independent determinants of reduced FC were LV diastolic function (higher E/E' ratio, p = 0.006), atrial fibrillation (p = 0.01), and lower forward stroke volume (p = 0.03). Clinical events (death, heart failure, new atrial fibrillation) and clinical events or surgery were more frequent with than without reduced FC (3 years, 36 +/- 14% vs. 13 +/- 4%, p = 0.02; and 66 +/- 11% vs. 29 +/- 5%, p = 0.001, respectively), even adjusting (risk ratios 1.80 and 1.54 respectively, both p < or = 0.03) for age and ERO.

CONCLUSIONS

In asymptomatic organic MR, FC quantitatively assessed by CPET is unexpectedly markedly reduced in one out of every four to five patients. Reduced FC is independently determined by consequences rather than severity of MR and predicts increased subsequent clinical events. Therefore, CPET frequently reveals functional limitations not detected clinically and is an important tool in managing patients with organic MR.

Early Exercise Training After Mitral Valve Repair

BACKGROUND

Surgical mitral valve (MV) repair is now the best technique to correct mitral regurgitation (MR). However, clinical studies have shown that without exercise training (ET), there is no significant postoperative exercise tolerance improvement. Moreover, healing duration of the MV wound is not well known; thus, the feasibility of an early ET program (ETP) may be discussed.

OBJECTIVES

To evaluate safety and feasibility of an early ETP after MV repair.

METHODS AND RESULTS

All patients hospitalized in 13 postoperative centers after MV repair from September 2002 to June 2003 were included in this prospective study. They underwent an ETP during 3 weeks on average. Transthoracic echocardiography and a cardiopulmonary exercise test were performed before and after the ETP.

PATIENTS

Two hundred fifty-one consecutive patients (male gender, 70%; mean age, 59 +/- 14 years [+/- SD]) were included 16 +/- 10 days after MV repair. There was no MR occurrence or worsening after the ETP. Left ventricular ejection fraction slightly increased (53 +/- 10% vs 55 +/- 9%, p = 0.004). Peak oxygen consumption and anaerobic threshold increased from 16.3 +/- 4.5 to 20.0 +/- 6.0 mL/kg/min (22% increase) and from 12.2 +/- 3.8 to 14.2 +/- 4.3 mL/kg/min (16% increase) respectively, (p < 0.0001).

CONCLUSION

ET after MV repair does not deteriorate the outcome of recent surgery and seems efficient.

Serum N-Terminal pro-BNP Levels Correlate with Symptoms and Echocardiographic Findings in Patients with Mitral Stenosis

This study is designed to evaluate the N-terminal pro-BNP (NTproBNP) levels in patients with mitral stenosis (MS) and its possible correlation with clinical and echocardiographic parameters of the disease. The study group consisted of 29 patients with isolated MS (patients with greater mild regurgitation were excluded) and 20 normal control subjects of similar age and gender distribution. Blood samples for NTproBNP were collected at the time of clinical and echocardiographic examination. NTproBNP levels were elevated in patients with MS compared to controls (325 +/- 249 pg/dL [19.9-890] versus 43 +/- 36 pg/dL [5.76-193.3], P < 0.001). Patients with atrial fibrillation had significantly higher NTproBNP levels compared to those with sinus rhythm (561 +/- 281 pg/dL versus 254 +/- 194 pg/dL, P = 0.044). MS patients with sinus rhythm also had higher NTproBNP levels compared to controls (254 +/- 194 pg/dL versus 43 +/- 36 pg/dL, P = 0.00011). NT pro BNP levels correlated to the LA (R = 0.73, P < 0.0001) and RV (R = 0.41, P = 0.042) diameters, mitral valve area (R =-0.45, P = 0.025), mean mitral gradient (R = 0.57, P = 0.003), peak PAP (R = 0.7, P = 0.03), and NYHA functional class (R = 0.61, P = 0.007). In conclusion, serum NTproBNP levels correlate well with echocardiographic findings and functional class in patients with MS and can be used as a marker of disease severity. Additionally, it may have a potential use as an additional noninvasive and relatively cheap method in monitoring disease progression especially in patients with poor echocardiographic windows.

Cardiopulmonary exercise testing before and one year after mitral valve repair for severe mitral regurgitation

For the evaluation of efficacy of cardiopulmonary exercise testing, we compared New York Heart Association functional class with peak oxygen consumption rate (VO(2)peak) in 31 patients with severe mitral regurgitation who underwent mitral valve repair surgery. One year later, the VO(2)peak values did not show significant improvement; however, the patients who had more than a mild degree of residual mitral regurgitation (n = 14) after 1 year of surgery had a VO(2)peak value that was significantly decreased (from 22.7 +/- 6.4 to 21.0 +/- 6.3 ml/kg/min, p = 0.04). Patients with a higher preoperative VO(2)peak value (>/=18.5 ml/kg/min) had a significantly better New York Heart Association functional class 1 year after surgery than patients with a lower VO(2)peak value (<18.5 ml/kg/min, p = 0.03).

Changes in systemic sympathetic nervous system activity after mitral valve surgery and their relationship to changes in left ventricular size and systolic performance in patients with mitral regurgitation

BACKGROUND

We have shown that the systemic sympathetic nervous system (SNS) is activated in patients with chronic mitral regurgitation (MR). However, the fate of systemic SNS activity after surgical correction of MR is currently unknown.

METHODS

We examined 14 patients with MR who had normal sinus rhythm with an investigational, preoperative cardiac catheterization, including arterial norepinephrine (NE) sampling and [(3)H]-NE infusions and arterial blood sampling to determine NE kinetic parameters using a 2-compartment modeling analysis. The arterial NE and NE kinetic parameters were determined in all patients after mitral valve surgery (MVS) at a mean of 12 months. A 2-dimensional echocardiographic examination was also performed before and after MVS.

RESULTS

The average extravascular NE release rates (NE(2)) before and after MVS were 1.89 +/- 0.66 and 2.26 +/- 0.82 microg/min/m(2) (P =.24), respectively. The average left ventricular (LV) end-diastolic dimension, fractional shortening, and ejection fraction decreased, whereas the mean LV end-systolic dimension did not change between the pre- and post-MVS echocardiographic studies. However, these group averages were comprised of patients with MR in whom the NE(2) and echocardiographic values both increased and decreased. This lack of homogeneity was a reflection of our new observation that the pre- to post-MVS changes in NE(2) were directly proportional to the changes in LV end-systolic dimension (r = 0.91, P <.001) and inversely related to the changes in LV fractional shortening (r = -0.82, P <.001) and ejection fraction (r = -0.78, P <.001).

CONCLUSIONS

The response in systemic SNS activity in patients with MR after MVS is not homogeneous, and these changes are concordant with the post-MVS changes in LV size and systolic performance. These data further support our earlier observations and extend them to suggest that systemic SNS activation in patients with chronic MR is related to LV remodeling and impaired systolic performance.

Surgical management of heart failure

This article introduces the mechanisms and theories behind the surgical treatments for heart failure; however, heart failure is a complex problem and requires multiple solutions. Surgery offers treatment strategies that target underlying physiologic changes and may provide both quality of life and survival benefit to patients who have specific clinical characteristics consistent with the aims of the procedure. Nurses must include surgical treatment early in their hierarchy of treatment plans, especially when coronary artery occlusion, hibernating myocardium, or mitral valve regurgitation is the cause of heart failure. In addition, newer investigational surgical therapies must also be considered for patients with advanced heart failure who have already been optimized on medical and cardiac resynchronization therapies and who require a novel approach to potentially improve individual outcomes.

The role of cardiopulmonary exercise test in mitral and aortic regurgitation: it can predict post-operative results

BACKGROUND

We evaluated the efficacy of the cardiopulmonary exercise test as an objective indicator of functional status and as a pre-operative prognostic indicator in patients with mitral regurgitation (MR) and aortic regurgitation (AR).

METHODS

Cardiopulmonary exercise tests and echocardiography were performed in 47 patients (MR: 30, AR: 15, MR + AR: 2) before surgery and repeated one year after surgery. We compared the New York Heart Association (NYHA) functional class, peak oxygen consumption rate (VO2peak), exercise duration, left ventricular dimension and ejection fraction, before and after surgery.

RESULTS

Initial VO2peak and exercise duration were significantly different according to NYHA class. A year later, NYHA functional class improved from 2.1 +/- 0.1 to 1.4 +/- 0.1 (p < 0.001). The VO2peak was significantly increased (21.7 +/- 1.0 to 23.7 +/- 1.0 mL/kg per min, p = 0.008) and exercise duration also increased (521.7 +/- 35.9 to 623.3 +/- 35.7 seconds, p < 0.001). When patients were analysed according to their post-operative NYHA functional class, those with class I showed significantly different pre-operative VO2peak (class I: 23.7 +/- 1.1, II: 18.3 +/- 1.5 mL/kg per min, p = 0.005) and exercise durations (class I: 587.5 +/- 43.2, II: 415.6 +/- 55.7 seconds, p = 0.02). Patients with higher pre-operative VO2peak (19.0 mL/kg per min) more frequently became NYHA functional class I than those with a lower pre-operative VO2peak (76.7% vs. 35.3%, p = 0.02). But baseline left ventricular dimension and ejection fraction by echocardiography were not different between post-operative class I and II group.

CONCLUSION

VO2peak and exercise duration are excellent parameters to evaluate the subjective functional class and to predict the post-operative functional class of patients with MR and/or AR. Patients with a pre-operative VO2peak of 19.0 mL/kg per min or more will have a better functional status one year after surgery.