Effects Of Mitral Valve Surgery Research Articles

710 The Effect of Mitral Valve Surgery on Left Ventricular Remodelling and Function in Paediatric Patients With Rheumatic Heart Disease: An Echocardiographic Study

Rheumatic heart disease (RHD) commonly results in mitral regurgitation (MR). The effects of left ventricular (LV) volume loading and alleviation on LV remodelling remains incompletely studied in children. MR in RHD allows investigation of haemodynamic measures without confounding congenital heart disease. We assessed the effects of MR and repair on LV myocardial mechanics, remodelling and function in children with RHD. Paediatric patients who underwent mitral valve repair or replacement for isolated RHD-MR from 2004 to 2019 with adequate echocardiographic studies were retrospectively assessed pre- and postoperatively and compared to matched controls. Eighteen patients underwent mitral valve surgery during the study period. Postoperatively there was a significant reduction in left atrial (LA) (p=0.001) and LV end-diastolic M-mode dimensions (p=0.001) and volumes (p=0.006), with no change in LV end-systolic volumes, yielding a significant reduction in LV functional measures (fractional shortening (34.5 vs 31.5%, p=0.006), four-chamber ejection fraction (62.6 vs 51.7%, p=0.002) and LV longitudinal strain (-24.3 vs -18.2%, p<0.001). Compared to controls, LA and LV dimensions remained increased with a reduction in all functional parameters after repair. There was a moderate negative correlation between preoperative end-diastolic volumes and postoperative longitudinal strain (r2=0.35). Persistent LV and LA remodelling with decreased LV function is observed after repair of RHD-MR. While these results reflect changes to volume loading, the unmasking of decreased LV function and persistent remodelling; and linear relation to preoperative LV size, may suggest that early intervention to alleviate MR could benefit selected patients and warrants further study.

Effect of Mitral Valve Surgery on Overnight Fluid Shift and Sleep Apnea in Patients With Moderate to Severe Mitral Valve Regurgitation and Preserved Ejection Fraction

SESSION TITLE: Sleep 2 SESSION TYPE: Original Investigation Poster PRESENTED ON: Wednesday, November 1, 2017 at 01:30 PM - 02:30 PM PURPOSE: Rostral fluid shift from the legs is strongly associated with sleep apnea (SA) in heart failure (HF) patients with reduced left ventricular ejection fraction (LVEF) accompanied by pulmonary congestion and/or pharyngeal edema. It is also known that sleep apnea is common among patients for cardiac surgery. Recent report showed that rheumatic valvular heart disease patients with obstructive SA had an increased incidence of perioperative complications, however the etiologies are unknown. Since MR contributes to pulmonary congestion and often have fluid retention in their legs, overnight fluid shift from the legs to the lungs or peripharyngeal area may play important roles in the pathogenesis of SA in patients with MR. Therefore, elucidating the relationship between fluid shift, SA, and effect of mitral valve (MV) surgery in patients with MR may provide some solutions. Purpose of this study is to investigate whether relationship between overnight fluid shit and severity of SA exists, and whether MV surgery affects either severity of SA and/or fluid shift, in patients with moderate-to-severe MR and preserved LVEF. METHODS: Patients with moderate-to-severe MR and preserved LVEF performed overnight polysomnography before and after the MV surgery. At the same time, leg fluid volume (LFV) was measured by bio-electrical impedance device before and after polysomnography. Relationship between overnight changes (△) of LFV and severity of SA as assessed by apnea-hypopnea index (AHI) was analyzed. RESULTS: Among 20 patients (mean age; 67±11 years, mean LVEF; 66±11%) enrolled, significant inverse relationship between △LFV and the AHI in univariable analysis (r=-0.78; P<0.001) was observed. Even in the multivariable regression analysis including other correlates to the AHI which showed P<0.1 in the univariable analyses, such as 24-hour urine volume (r=-0.46; P=0.041), regurgitant volume by PISA (r=0.46; P=0.049), use of diuretics (r=0.47; P=0.035) and beta blockers (r=054; P=0.014), △LFV was the significant correlates to the AHI (r=-0.72; P<0.001). 17 patients among them have done polysomnography after the surgery. Although body weight significantly decreased from 59.4±13.5 to 58.9±13.0 kg (P=0.004) following MV surgery, the AHI and △LFV did not change (AHI, from 27.9±18.5 to 31.4±18.0; P=0.463 and △LFV, from -397±188 to -401±202 ml; P=0.723). However, there were significant correlation between change in the AHI and change in △LFV, even after adjustment of change in the body weight (r=-0.58; P=0.035). CONCLUSIONS: Significant independent relationship between overnight fluid shift and SA severity were found in patients with moderate-to-severe MR and preserved LVEF. Despite no changes in AHI and LFV following MV surgery, there was a significant correlation between change in the AHI and change in △LFV. CLINICAL IMPLICATIONS: These findings suggest that in patients with moderate-to-severe MR and preserved LVEF, overnight rostral fluid displacement from the legs contributes to the pathogenesis of SA. Further investigation may contribute to reveal mechanisms. DISCLOSURE: Takatoshi Kasai: Grant monies (from industry related sources): affiliated with a department endowed by Philips Respironics, ResMed, and Fukuda Denshi The following authors have nothing to disclose: Azusa Murata, Shoichiro Yatsu, Hiroki Matsumoto, Takao Kato, Shoko Suda, Masaru Hiki, Kan Kajimoto, Taira Yamamoto, Atsushi Amano No Product/Research Disclosure Information

Effect of Mitral Valve Surgery in Patients With Dilated Cardiomyopathy and Severe Functional Mitral Regurgitation.

Surgical treatment of functional mitral regurgitation (FMR) improves ventricular remodeling in patients with dilated cardiomyopathy (DCM). However, it is unclear whether surgical treatment improves long-term outcomes. We investigated the effects of mitral valve (MV) surgery in patients with DCM and FMR.Methods and Results:Of 525 patients with DCM hospitalized due to heart failure between January 1996 and September 2014, 70 who had severe FMR despite receiving optimal medical therapy were enrolled in the study. Of these patients, 16 underwent surgery for FMR (surgery group; repair=14, replacement=2); the remaining 54 who refused or decided not to undergo surgery were classified as the medication group. There were no differences in age, sex, medication, or echocardiographic parameters between the 2 groups (P>0.05). During the mean follow-up period of 53.6±43.6 months, the occurrence of clinical outcomes (i.e., all-cause death or left ventricular assist device implantation) was 54.3%; the occurrence of clinical outcomes was lower in the surgery group (P=0.008, log-rank test). Multivariate Cox regression analysis using clinical data revealed that MV surgery (hazard ratio [HR] 0.257, 95% confidence interval [CI] 0.103-0.640; P=0.004) and diabetes mellitus (HR 2.924, 95% CI 1.243-6.876; P=0.014) were independent predictors of clinical outcomes after adjusting for age and sex. Surgery for severe FMR provides better long-term outcomes in patients with DCM.

The effect of mitral valve surgery on ventricular arrhythmia in patients with bileaflet mitral valve prolapse

BackgroundBileaflet mitral valve prolapse (biMVP) is associated with frequent ventricular ectopy (VE) and malignant ventricular arrhythmia. We examined the effect of mitral valve (MV) surgery on VE burden in biMVP patients. MethodsWe included 32 consecutive patients undergoing MV surgery for mitral regurgitation secondary to biMVP between 1993 and 2012 at Mayo Clinic who had available pre- and post-operative Holter monitoring data. Characteristics of patients with a significant reduction in postoperative VE (group A, defined as >10% reduction in VE burden compared to baseline) were compared with the rest of study patients (group B). ResultsIn the overall cohort, VE burden was unchanged after the surgery (41 interquartile range [16, 196] pre-surgery vs. 40 interquartile range [5186] beats/hour [bph] post-surgery; P = 0.34). However, in 17 patients (53.1%), VE burden decreased by at least 10% after the surgery. These patients (group A) were younger than the group B (59 ± 15 vs. 68 ± 7 years; P = 0.04). Other characteristics including pre- and postoperative left ventricular function and size were similar in both groups. Age <60 years was associated with a reduction in postoperative VE (odds ratio 5.8; 95% confidence interval, 1.1–44.7; P = 0.03). Furthermore, there was a graded relationship between age and odds of VE reduction with surgery (odds ratio 1.9; 95% confidence interval 1.04–4.3 per 10-year; P = 0.04). ConclusionsMV surgery does not uniformly reduce VE burden in patients with biMVP. However, those patients who do have a reduction in VE burden are younger, perhaps suggesting that early surgical intervention could modify the underlying electrophysiologic substrate.

Mitral valve repair in heart failure: Five-year follow-up from the mitral valve replacement stratum of the Acorn randomized trial

The study objective was to evaluate the long-term (5-year) safety and efficacy of mitral valve surgery with and without the CorCap cardiac support device (Acorn Cardiovascular, St Paul, Minn) in patients with dilated cardiomyopathy and New York Heart Association class II-IV heart failure. The Acorn trial provided a unique opportunity to assess the long-term safety and efficacy of mitral valve surgery because clinical visits and echocardiograms (read by a core laboratory) were completed for 5 years of follow-up. Further, this study provided follow-up data on the long-term effect of the CorCap cardiac support device as an adjunct to mitral valve surgery. From the original Acorn trial (n = 300 patients), 193 patients were enrolled in the mitral valve repair/replacement stratum. A total of 102 were randomized to mitral valve surgery alone (control group) and 91 were randomized to mitral valve surgery with implantation of the CorCap cardiac support device (treatment group). Patients were followed up for 5 years. As previously reported, 30-day operative mortality was only 1.6%. At 5 years, the total mortality was 30% with an average annual mortality rate of approximately 6% per year. The effects of mitral valve surgery led to a progressive decrease in left ventricular end-diastolic and end-systolic volumes, which were highly significant at all time points. At the end of 5 years, there was an average reduction in left ventricular end-diastolic volume of 75 mL, which represents a 28% reduction from baseline. During 5 years of follow-up, 29 patients had recurrent mitral regurgitation and 5 patients underwent repeat mitral valve surgery. The addition of the CorCap device led to greater decreases in left ventricular end-diastolic volume (average difference of 16.5 mL; P = .05), indicating that the CorCap device had an additive effect to the mitral valve operation. This study demonstrates long-term improvement in left ventricular structure and function after mitral valve surgery for up to 5 years. These data provide evidence supporting mitral valve repair in combination with the Acorn CorCap device for patients with nonischemic heart failure with severe left ventricular dysfunction who have been medically optimized yet remain symptomatic with significant mitral regurgitation.

Effects of Mitral Valve Surgery on Myocardial Energetics in Patients With Severe Mitral Regurgitation

Hemodynamically significant mitral regurgitation (MR) may alter left ventricular (LV) myocardial energy requirements. The effects of MR and subsequent corrective mitral valve (MV) surgery on myocardial energetics are not well understood. A better understanding of myocardial energetics and the LV responses to changes in preload and afterload may assist with the understanding of mitral regurgitation and its effect on the LV. We sought to determine the effects of MV surgery on forward stroke work, myocardial oxidative metabolism, and myocardial efficiency. Prospectively enrolled patients with chronic, severe, nonischemic mitral regurgitation underwent echocardiography, radionuclide angiography, and C-11 acetate positron emission tomography to measure LV volumes, ejection fraction, and oxidative metabolism before and 1 year after MV surgery. Forward and total stroke work corrected for oxidative metabolism was used to estimate efficiency using the work metabolic index. Fourteen patients (age, 59+/- 8 years) with myxomatous MV were enrolled. One year after MV surgery, there was a reduction in LV end-diastolic and end-systolic volumes (231+/-86 to 131+/-21 mL; P<0.01 and 98+/-53 to 55+/-17 mL; P<0.01). Forward stroke volume increased (58.1+/-15.0 to 75.5+/-23 mL; P<0.01), LV ejection fraction was preserved without a significant change in oxidative metabolism. Forward work metabolic index improved (4.99+/-1.32 x 10(6) to 6.59+/-2.45 x 10(6) mm Hg x mL/m(2); P=0.02). This was not at the expense of total work metabolic index, which was preserved. MV surgery has a beneficial effect on forward stroke volume and forward work metabolic index without adverse effects on oxidative metabolism or total work metabolic index.

The Effect of Mitral Valve Surgery on Left Atrial Volume and Function in Severe Mitral Regurgitation

The Effect of Mitral Valve Surgery on Left Atrial Volume and Function in Severe Mitral Regurgitation

Surgical therapy for mitral regurgitation: The key to preventing heart failure?

Five million Americans suffer from heart failure (HF). Despite innovative new pharmacologic and device therapies, the 5-year mortality rate for patients remains near 50%. Conservatively, 300,000 patients with HF also have severe functional mitral regurgitation. Over the past decade, the surgical approach to these patients has become more aggressive because the extent of the problem has become widely recognized, and surgeon familiarity with annuloplasty techniques has increased. Although clinical experience and enthusiasm have resulted in an expansion of literature, the role that mitral valve repair surgery plays in the treatment of HF is not fully established. In this article, we review the existing data on the efficacy of mitral valve surgery in HF patients. Specifically, we will review the available data regarding the effect of mitral valve surgery on longevity, ventricular remodeling, and symptoms. No randomized prospective data are available, but careful analysis of existing retrospective studies allows important conclusions to be made.

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

OBJECTIVESThe purpose of this study was to prospectively investigate the effects of surgical correction of mitral regurgitation (MR) on exercise performance, cardiac function and neurohormonal activation.BACKGROUNDLittle is known about the effect of surgical correction of MR on functional status or on neurohormonal activation.METHODSCardiopulmonary exercise test, radionuclide angiography and blood samples for assessment of neurohormonal status were obtained in 40 patients with nonischemic MR before and within one year (216 ± 80 days) after surgery. Twenty-four patients underwent mitral valve repair (MVr), and 16 underwent valve replacement (VR) with anterior chordal transection.RESULTSDespite an improvement in New York Heart Association functional class, exercise performance did not change (peak oxygen consumption: 19.3 ± 6.1 to 18.5 ± 5.6 ml/kg/min, percentage of maximal predicted oxygen consumption: 79.5 ± 18.2% to 76.8 ± 16.9%). After surgery, left ventricular (LV) ejection fraction (EF) decreased (64.2 ± 10.3% to 59.9 ± 11.4%, p = 0.003) while right ventricular (RV) EF increased (41.4 ± 9.6% to 44.7 ± 9.5%, p = 0.03). Left ventricular EF did not change after MVr (64.3 ± 11.5% to 61.5 ± 12.2%), but RVEF improved (40.4 ± 9.2% to 46.0 ± 10.0%, p = 0.02). In contrast, VR was associated with an impairment of LV function in the apicolateral area and a decrease in LVEF (64.1 ± 8.5% to 57.4 ± 10.0%, p = 0.01), whereas RVEF did not change (42.9 ± 10.3% to 42.8 ± 8.6%). Moreover, there was only a slight decrease in neurohormonal activation after surgery.CONCLUSIONSDespite an improvement in symptomatic status, exercise performance was not improved seven months after either MVr or VR for MR, and neurohormonal activation persisted. Compared with MVr, VR resulted in a significant impairment of cardiac function in this study.

Effect of mitral valve surgery on severely impaired pulmonary function.

To evaluate the effect of surgery on severely impaired pulmonary function associated with mitral valve disease, we examined the relationship between postoperative improvements in pulmonary function and pulmonary circulation in 238 patients who underwent mitral valve surgery. Of these patients 17 met the preoperative criteria for severely impaired pulmonary function: forced expiratory volume in 1 second = FEV1 < or = 1000 ml. They showed average values for vital capacity (VC) of 1343 +/- 203 ml, for % of vital capacity for predicted values (%VC) of 52.0 +/- 6.5%, and for FEV1 of 851 +/- 104 ml. Moderate elevations of mean pulmonary arterial pressure (PAP: 36.2 +/- 10.2 mmHg), mean pulmonary arterial wedge pressure (PAWP: 23.0 +/- 9.6 mmHg), and pulmonary vascular resistance (PVR: 329 +/- 147 dyne.sec.cm-5) were also observed. Postoperatively, 4 of the 17 patients required long-term respiratory support for more than one week, and 3 patients died in hospital; this mortality rate, however, was not significantly different to that of patients with preoperative FEV1 > 1000 ml. In long-surviving patients, pulmonary function improved in the late postoperative period. Significant relationships were recognized between delta FEV1 (delta: postoperative value--preoperative value) and delta PAP, delta PAWP, and delta PVR. The delta VC and delta %VC also correlated significantly with delta PAP, delta PAWP and delta PVR. In conclusion, in patients with mitral valve disease impaired pulmonary function cannot be used to exclude patients from operation. Furthermore, severely impaired pulmonary function should improve with the improvement of pulmonary circulation after surgery.

Preoperative and postoperative right ventricular function during exercise in patients with mitral stenosis

To elucidate the effects of mitral valve surgery on right ventricular function in 11 patients with mitral stenosis, pre- and postoperative right ventricular function were quantified using gated equilibrium blood pool radionuclide ventriculography at rest and during exercise. The preoperative right ventricular ejection fraction was 39 +/- 4% at rest and 36 +/- 9% during exercise, which during exercise was lower than control values (51 +/- 5%) (p < 0.01). When the preoperative right ventricular ejection fraction was lower during exercise than at rest, postoperative right ventricular ejection fraction during exercise was lower than normal values (42 +/- 3% versus 51 +/- 5%) (p < 0.01). When the preoperative right ventricular ejection fraction did not decrease during exercise, the postoperative right ventricular ejection fraction was within normal limits during exercise (54 +/- 5%). In addition, postoperative right ventricular ejection fraction during exercise increased to normal values in patients whose preoperative right ventricular ejection fraction during exercise had been 40% or higher. Preoperative peak ejection rate was -1.81 +/- 0.19 EDV/sec at rest and -1.72 +/- 0.39 EDV/sec during exercise, which during exercise was lower than control values (-2.44 +/- 0.53 EDV/sec) (p < 0.01). Postoperatively, peak ejection rate during exercise (-2.50 +/- 0.37 EDV/sec) increased (p < 0.05) to normal levels. Preoperative peak filling rate was 1.61 +/- 0.47 EDV/sec at rest and 1.88 +/- 0.54 EDV/sec during exercise, which during exercise was lower than control values (2.58 +/- 0.62 EDV/sec) (p < 0.01). Postoperatively, peak filling rate during exercise (2.82 +/- 0.62 EDV/sec) increased (p < 0.05) to normal values in all patients. Preoperative changes in both right ventricular ejection fraction and peak ejection rate from rest to exercise inversely correlated with the preoperative pulmonary vascular resistance at rest (right ventricular ejection fraction, r = -0.79, p < 0.005; and peak ejection rate, r = -0.67, p < 0.05). In conclusion, right ventricular systolic function improved in about half of the patients with mitral stenosis, and diastolic function improved in all patients during exercise following surgery. When the preoperative pulmonary vascular resistance was elevated, the right ventricular systolic dysfunction persisted.

Effects of mitral valve surgery on static lung function and exercise performance.

Lung function at rest was assessed in 50 patients before and six months after mitral valve surgery. There were small increases in spirometric volumes (FEV1 and vital capacity) with decreases in total lung capacity and residual volume, but no change in carbon monoxide transfer factor or transfer coefficient (KCO). Progressive exercise tests performed before and after operation in 19 of the patients confirmed an improved exercise capacity after surgery. The patients with the greatest symptomatic improvement in breathlessness were also those who achieved the greatest increase in maximum work load and the greatest decrease in ventilation for a given oxygen consumption. Depression of the ST segment of the electrocardiogram and frequent ventricular ectopic beats on exercise remained common after surgery and may have been due to digoxin treatment.

Assessment of prognostic factors in patients undergoing surgery for non-rheumatic mitral regurgitation.

Twenty-four patients who had undegone mitral valve surgery for pure non-rheumatic mitral regurgitation were studied non-invasively six months to six years postoperatively. The long-term results of operation were assessed on the basis of clinical history, echocardiography, and treadmill stress testing using a points scoring system. The score so obtained was used to divide the patients into those with a good response to surgery (group 1) and those responding poorly (group 2). The effects on the long-term surgical outcome of several intraoperative and preoperative factors were then analysed both together and separately. A short symptomatic history (less than 1 year), a normal left ventricular end-diastolic volume index (less than or equal to 100 ml per m2), and a large post-ectopic potentiation of KV max (greater than 50 s-1) were found to be favourable prognostic factors when analysed independently. An angiographic ejection fraction less than 0.5 was uniformly associated with a poor outcome, and 71 per cent of patients in atrial fibrillation at the time of operation also responded badly. In those patients with good long-term function, cold potassium cardioplegia was more commonly used than intermittent aortic cross clamping as the means of intraoperative myocardial preservation, though this difference did not reach conventional significance. A standard analysis of variance allowed assessment of length of history, left ventricular end-diastolic volume index, and type of valve prosthesis simultaneously. This indicated that both length of history and left ventricular end-diastolic volume index were highly significant prognostic factors. The use of a Björk-Shiley as opposed to a Starr-Edwards prosthesis also emerged as significantly favouring a good long-term result. The state of the left ventricular myocardium before operation and the type of valve prosthesis used were thus shown to be the prime determinants of surgical outcome in these patients. The optimum time for operation was shown to be within one year of the onset of symptoms, and before the left left ventricular end-diastolic volume index exceeds 100 ml per m2, or the ejection fraction falls to less than 0.5. At such a time, irreversible changes in myocardial function sufficient to negate the beneficial effects of mitral valve surgery have not yet occurred.

Echocardiographic assessment of left ventricular filling after mitral valve surgery.

In order to investigate the functional effects of mitral valve surgery, echocardiograms showing left ventricular dimension were recorded and digitised in 14 normal subjects and 129 patients after mitral valve surgery. Measurements were made of peak rate of increase of dimension (dD/dt) and duration of rapid filling, studies on left ventriculograms in 36 patients having shown close correlation between these values and changes in cavity volume. In 14 patients with mitral stenosis, peak dD/dt was reduced to 7-2 +/ 1-5 cm/s, and filling period prolonged to 330 +/- 65 ms, compared with normal (16-0 +/- 3-2 cm/s, and 160 +/- 50 ms, respectively), and after mitral valvotomy, these values improved significantly (10-4 +/- 2-7 cm/s and 245 +/- 55 ms). Characteristic abnormalities were found in 67 patients with mitral prostheses. Values for the Björk-Shiley (10-5 +/- 4-2 cm/s and 180 +/- 80 ms) and Hancock (10-3 +/- 3-7 cm/s, 245 +/- 80 ms) values were similar, and both superior to the Starr-Edwards (7-4 +/- 3-0 cm/s, 295 +/- 105 ms). Results after mitral valve repair in 30 cases were not significantly different from normal (14-4 +/- 5-0 cm/s, 170 +/- 50 ms). Values outside the 95 per cent confidence limits for the valve in question allowed diagnosis of value malfunction in 18 cases. The method is value in comparing different operative procedures and in following up patients after mitral valve surgery.

The use of simultaneous left heart pressure pulse measurements in evaluating the effects of mitral valve surgery

1. 1. The need for an objective method of measuring the adequacy of mitral valvulotomy by estimating the extent of residual mitral stenosis is emphasized. 2. 2. Measurement of the mitral valve filling pressure gradient appears to be the best method of determining the degree of hemodynamically significant mitral stenosis. A method for recording the pressure gradient between the left auricle and the left ventricle at the operating table, by inscribing simultaneous pressure pulses in the left heart, is described. 3. 3. The normal filling pressure gradient across the mitral valve approximates zero. The effect of valvulotomy on the elevated pressure gradient in mitral stenosis is to produce a fall of variable degree, depending on the adequacy of the surgical procedure. When this pressure gradient remains high after valvulotomy, relief of the obstruction can be termed inadequate. 4. 4. The method is also of value in the differential diagnosis of mitral stenosis, in aiding the surgeon at the operating table to decide whether sufficient manipulation of the valve has been carried out and in determining whether recurrence of obstruction has taken place in patients previously operated upon for mitral stenosis.