Does Stringent Restrictive Annuloplasty for Functional Mitral Regurgitation Cause Functional Mitral Stenosis and Pulmonary Hypertension?
Background—It remains controversial whether restrictive mitral annuloplasty (RMA) for functional mitral regurgitation (MR) can induce functional mitral stenosis (MS) that may cause postoperative residual pulmonary hypertension (PH).
Methods and Results—One hundred eight patients with left ventricular (LV) dysfunction and severe MR underwent RMA with stringent downsizing of the mitral annulus. Systolic pulmonary artery pressure (PAP) and mitral valve performance variables were determined by Doppler echocardiography prospectively and 1 month after RMA. Fifty-eight patients underwent postoperative hemodynamic measurements. Postoperative echocardiography showed a mean pressure half-time of 92±14 ms, a transmitral mean gradient of 2.9±1.1 mm Hg, and a mitral valve effective orifice area of 2.4±0.4 cm2, consistent with functional MS. Doppler-derived systolic PAP was 32±8 mm Hg, which correlated weakly with the transmitral mean gradient (ρ=0.23, P=0.02). Postoperative cardiac catheterization also showed significant improvements in LV volume and systolic function, pulmonary capillary wedge pressure, cardiac index, and systolic PAP; the latter was associated with LV end-diastolic pressure [standardized partial regression coefficient (SPRC)=0.51], pulmonary vascular resistance (SPRC=0.47), cardiac index (SPRC=0.37), and transmitral pressure gradient (SPRC=0.20). In a multivariate Cox proportional hazard model, postoperative PH (systolic PAP >40 mm Hg), but not mitral valve performance variables, was strongly associated with adverse cardiac events.
Conclusions—RMA for functional MR resulted in varying degrees of functional MS. However, our data were more consistent with the residual PH being caused by LV dysfunction and pulmonary vascular disease than by the functional MS. The residual PH, not functional MS, was the major predictor of post-RMA adverse cardiac events.
- functional mitral regurgitation
- restrictive mitral annuloplasty
- functional mitral stenosis
- pulmonary hypertension
- patient-prosthesis mismatch
Restrictive mitral annuloplasty (RMA), which involves the insertion of an undersized prosthetic ring, has become the preferred surgical option for the treatment of patients with medically uncontrollable, severe functional mitral regurgitation (MR). Previous studies1–4 have shown that stringent RMA can effectively eliminate functional MR, resulting in reverse left ventricular (LV) remodeling, and improved symptoms, and survival in the great majority of patients.
In contrast to these beneficial effects of the RMA procedure, Magne et al5 first reported that the insertion of such an undersized ring may induce an iatrogenic “functional” mitral stenosis (MS) similar to prosthesis-patient mismatch (PPM), a condition that is frequently found after mitral valve replacement with a small prosthetic valve.6–8 The effective orifice area (EOA) of a prosthetic valve or annuloplasty ring is often too small in relation to body size, causing a mismatch between the EOA and the transmitral flow, and yielding relatively high gradients. Several recent studies have reported a high incidence of functional MS, in which the mitral valve area is less than 1.5 cm29 or the mean pressure gradient is greater than 5 mm Hg, after RMA.10 In contrast, most prior echocardiographic studies did not describe problems with functional MS or ring PPM after mitral valve repair using an undersized annuloplasty ring.3,4
Magne et al5 also found that this hemodynamic consequence (functional MS) may be associated with residual pulmonary hypertension (PH) after RMA. However, little data from invasive hemodynamic monitoring techniques with regard to functional MS have been reported. The purpose of this study was to evaluate the post-RMA hemodynamic data, to determine whether stringent RMA for functional MR results in functional MS, and whether this hemodynamic consequence is mainly responsible for residual PH after the operation. We also attempted to determine factors predicting residual PH and short-term outcome in patients undergoing the RMA procedure.
Between July 2003 and November 2009, 195 patients underwent RMA for functional MR using a semirigid complete ring (Carpentier-Edwards Physio ring; Edwards Lifesciences, Irvine, CA) at 3 university-affiliated hospitals. Functional MR associated with cardiomyopathy was defined as a combination of moderate-to-severe MR with (1) a history of at least 1 hospitalization for heart failure in the previous 6 months, despite maximal medical treatment, (2) global LV dysfunction (LV ejection fraction <40%) with a significantly enlarged left ventricle, and (3) type IIIb leaflet dysfunction, according to Carpentier classification. Of these patients, 87 were excluded because of concomitant surgical ventricular reconstruction (n=69), redo mitral valve surgery owing to MR recurrence (n=4), postoperative infective endocarditis (n=2), or early hospital death (n=12). The final study population consisted of 108 patients (86 men, 22 women), who had a mean body surface area (BSA) of 1.65±0.19 cm2 (range, 1.30 to 2.26). Because the patients with a 26-mm Physio ring had a larger BSA than those with a 24-mm Physio ring, patient baseline characteristics are presented according to the size of the ring (Table 1). Before surgical referral, all the patients had been treated with optimized medical regimens by his or her attending cardiologist, including angiotensin-converting enzyme inhibitors or angiotensin-receptor blockers, β-blockers, and diuretics.
Ethical committee approval was obtained from each institution, and individual consent was waived for this retrospective analysis. Written informed consent for the procedure was obtained from each patient before surgery.
Two-dimensional and Doppler transthoracic echocardiography examinations were performed before and 1 month after surgery. All echocardiographic studies were done using commercially available 3.75-MHz transducers (Toshiba, Tokyo, Japan, and Hewlett-Packard Sonos) by expert echocardiographic examiners who were blinded to the clinical status of the patients and their operative data. Echocardiographic measurements included LV end-diastolic and end-systolic dimensions, LA dimension, LV ejection fraction, and right ventricular (RV) end-diastolic dimension. Postoperative transmitral mean gradient were measured by Doppler echocardiography. The mitral valve EOA was determined by the pressure half-time method11 and indexed for BSA. The severity of regurgitation was classified as none (0), trivial (1+), mild (2+), moderate (3+), or severe (4+) in the present study.
Doppler-Derived Pulmonary Artery Pressure
Systolic pulmonary artery pressure (PAP) was calculated by adding the systolic pressure gradient across the tricuspid valve derived from tricuspid regurgitation, to the estimated right atrial pressure value.12,13
Right and left heart catheterization procedures were performed, using standard techniques before and 1 month (within 1 day of echocardiography) after surgery. The purposes of the cardiac catheterization and the invasive nature of the procedure were explained in detail to all patients, and only those who gave informed consent underwent catheterizations. The indications for postoperative catheterization were not selective. None had complications at the preoperative or postoperative catheterization. As a result, preoperative coronary arteriography was performed for all 108 patients, but left ventriculography and hemodynamic measurements were performed for 97 (90%) and 75 (69%), respectively. After surgery, 89 of the 108 patients (82%) underwent left ventriculography and 58 (54%) underwent hemodynamic measurements.
Before left ventriculography, standard pressure measurements were obtained to evaluate the LV systolic pressure, LV end-diastolic pressure (LVEDP), pulmonary capillary wedge pressure (PCWP); systolic, diastolic, and mean PAP; RV systolic pressure, RVEDP, and right atrial pressure. Right-sided pressures were obtained using a Swan-Ganz catheter. Cardiac output was determined with the thermodilution method. In addition, the systemic vascular resistance (SVR) and pulmonary vascular resistance (PVR) were also calculated.
Hemodynamic Assessment of Mitral Valve Performance
The gradient across the mitral valve was calculated as the pressure difference between mean PCWP and LVEDP, although it is better to determine transmitral gradients using simultaneous recordings.
Classification of the Severity of MS, Prosthesis-Patient Mismatch, and PH
MS severity was categorized classically as mild (EOA >1.5 cm2, mean gradient <5 mm Hg), moderate (EOA 1.0 to 1.5 cm2, mean gradient 5 to 10 mm Hg), or severe (EOA <1.0 cm2, mean gradient >10 mm Hg).
Indeed, there is no single parameter that defines the severity of functional MS that is possibly induced by an RMA procedure. In the present study, functional MS severity was categorized according to the level of the in vivo EOA in relation to patient body size; PPM was defined as mild and not clinically significant if the indexed EOA was >1.2 cm2/m2, as moderate if it was >0.9 to 1.2 cm2/m2, and as severe if it was ≤0.9 cm2/m2.8
The severity of PH was also categorized as mild (systolic PAP <40 mm Hg), moderate (systolic PAP 40 to 60 mm Hg), or severe (systolic PAP >60 mm Hg).
A median sternotomy was performed under a mild hypothermic cardiopulmonary bypass with intermittent cold blood cardioplegia. A stringent restrictive (2 to 3 sizes smaller than measured) mitral annuloplasty was performed for all patients. The ring size was selected according to the surgeon's preference (Ka.T., T. M., and Y.S.) at each hospital, considering the patient's body size. Sixty-six (61%) patients received a 24-mm Physio ring (geometric orifice area, 2.74 cm2) and 42 (39%) a 26-mm Physio ring (geometric orifice area, 3.25 cm2). Data regarding the geometric orifice area of the ring were supplied by the manufacturer. All relevant surgical data are summarized inTable 1.
Clinical follow-up examinations were completed for all 108 patients (100%), with a mean duration of 33±18 months. Every 6 months to 1 year, each patient was assessed in the department as well as by his or her primary cardiologist. A retrospective review of the medical records of these patients was performed to obtain the preoperative and postoperative data. Current information was obtained by calling the patient or the referring cardiologist. We also reviewed the postoperative adverse cardiac events defined as late cardiac-related death, myocardial infarction, thromboembolism, readmission for heart failure, and ventricular arrhythmia requiring implantation of an intracardiac defibrillator.
Continuous variables are summarized as mean±SD and categorical variables as frequencies and proportions. All the continuous variables were checked for normality using the Shapiro-Wilk test and normal probability plot. Normally distributed variables were compared using the Student t test and nonnormally distributed variables were compared with the Mann-Whitney U test. Categorical variables were compared using the χ2 analysis or Fisher exact test, as appropriate. Preoperative and postoperative hemodynamic variables were assessed by repeated-measures ANOVA with group, time, and group-time interaction effects. Nonnormally distributed variables tested in the repeated ANOVA were natural log-transformed to satisfy normality of the used models, as appropriate. Correlation between nonnormally distributed variables were tested with Spearman correlation coefficient (ρ).
Stepwise multiple linear regression analyses were performed to identify the determinants of Doppler-derived or catheter-measured systolic PAP. The Doppler-derived systolic PAP and catheter-measured systolic PAP were natural log-transformed to satisfy normality of the used models. Factors obtaining a probability value less than 0.1 in the univariate analysis, based on Spearman correlation coefficient were then entered appropriately into the stepwise multiple linear regression model. Regression diagnostics was used to assess the obtained models for collinearity and residual nonnormality and heteroscedasticity. The results are summarized as correlation coefficients (ρ) and standardized partial regression coefficients (SPRCs).
Univariate and multivariate analyses of the predictors for adverse cardiac time to events were performed using Cox proportional hazards models. Factors obtaining a probability value less than 0.1 in the univariate Cox proportional hazards analysis were then entered appropriately into the multivariate fashion, using stepwise variable selection. The results are summarized as hazard ratios (HRs) and 95% confidence intervals (CIs). Statistical significance was defined as a probability value <0.05. Statistical analyses were performed using JMP 7.0 (SAS Institute, Cary, NC) and SPSS software (version 17.0, SPSS Inc).
Postoperative Echocardiographic Data
After surgery, none of the patients showed a significant (>2+) level of residual MR (Table 2). The pressure half-time was 92±14 ms in all the patients (range, 67 to 129 ms versus normal value, 40 to 60 ms), which was prolonged and suggested the presence of gradients across the mitral valve. The transmitral mean gradient value was 2.9±1.1 mm Hg (range, 1.1 to 6.2 mm Hg). Ninety-eight of the 108 patients (91%; 95% CI, 84% to 95%) had a transmitral mean gradient value <5 mm Hg (mild MS), whereas 10 (9%; 95% CI, 5% to 16%) had a mean gradient value ≥5 mm Hg (moderate MS). The mitral valve EOA value was 2.4±0.4 cm2 (range, 1.7 to 3.3 cm2), and none of the patients had a value <1.5 cm2. The indexed EOA value was 1.51±0.32 cm2/m2 (range, 0.84 to 2.46 cm2/m2). Twenty-one (19%; 95% CI, 13% to 28%) showed moderate PPM (an indexed EOA >0.9 to ≤1.2 cm2/m2), and 2 (2%; 95% CI, 0.5 to 6.5%) had severe PPM (an indexed EOA ≤0.9 cm2/m2). The mean value for systolic PAP was 32±8 mm Hg (range, 18 to 53 mm Hg). Seventeen patients (16%; 95% CI, 11% to 26%) showed moderate PH (systolic PAP, 40 to 60 mm Hg), and none had severe PH (systolic PAP >60 mm Hg) after surgery. Notably, patients with a 24-mm ring had a greater mean transmitral gradient, smaller mitral valve EOA, and longer pressure half-time compared with those with a 26-mm ring, whereas there was no difference between the groups with regard to the indexed EOA and systolic PAP. In general, the transmitral mean gradient correlated inversely with the indexed EOA value (ρ=−0.30 P=0.002), and correlated positively with the BSA (ρ=0.27, P=0.006).
Other LV dimension and function variables substantially improved in both groups.
Determinants of Postoperative Doppler-Derived Systolic PAP 1 Month After RMA
Postoperative Doppler-derived systolic PAP correlated with the Doppler-derived transmitral mean gradient (ρ=0.23, P=0.02) but did not correlate with the EOA or indexed EOA (Table 3). Postoperative systolic PAP also correlated with the catheter-derived postoperative PCWP (ρ=0.40, P=0.002), LVEDP (ρ=0.38, P=0.004), and PVR (ρ=0.66, P<0.001). Multivariate analysis showed that PVR had the most important contribution (SPRC=0.62), followed by LVEDP (SPRC=0.28), whereas the transmitral gradient had a minimal contribution (SPRC=0.24). Postoperative PCWP was not entered into the multivariate analysis because of a strong correlation between PCWP and LVEDP (ρ=0.87). Regression diagnostics showed no evidence of collinearity and residual nonnormality and heteroscedasticity in the obtained models.
Preoperative and Postoperative Hemodynamic Data
From baseline to 1 month after surgery, LV volumes decreased and ejection fraction improved in both patient groups (Table 4). LV systolic pressure did not change, whereas LVEDP, PCWP, systolic, and mean PAP decreased significantly. Other hemodynamic parameters such as cardiac index, PVR, and SVR also improved significantly or showed a trend toward normal in both groups. Importantly, there were no differences in postoperative LV function or hemodynamic parameters between the 2 groups, which received different sized rings.
The postoperative transmitral pressure gradient value, calculated as the pressure difference between mean PCWP and LVEDP, was 3.0±1.2 mm Hg (range, 1 to 7 mm Hg). The mean value for catheter-measured postoperative systolic PAP was 33±8 mm Hg (range, 18 to 54 mm Hg). Fifteen of the 58 patients (26%; 95% CI, 16% to 38%) showed moderate PH (systolic PAP, 40 to 60 mm Hg), and none had severe PH (systolic PAP, >60 mm Hg) after surgery. Notably, patients with a 24-mm ring had greater transmitral pressure gradients compared with patients with a 26-mm ring, whereas there was no difference in systolic PAP between the groups. There were also no differences for the other hemodynamic measurements.
In general, the transmitral pressure gradient correlated positively with cardiac output (ρ=0.77, P<0.001) and heart rate (ρ=0.27, P=0.05).
Determinants of Postoperative Catheter-Measured Systolic PAP 1 Month After RMA
In univariate analyses, the postoperative catheter-measured systolic PAP correlated with the PCWP (ρ=0.70, P<0.001), LVEDP (ρ=0.56, P<0.001), transmitral pressure gradient (ρ=0.52, P<0.001), cardiac index (ρ=0.28, P=0.04), and PVR (ρ=0.54, P<0.001) (Table 5). Multivariate analysis showed that LVEDP had the most important contribution (SPRC=0.51), followed by PVR (SPRC=0.47) and the cardiac index (SPRC=0.37), whereas the transmitral pressure gradient had a minimal contribution (SPRC=0.20). Postoperative PCWP was not entered into the multivariate analysis because of a strong correlation between PCWP and LVEDP (ρ=0.87). Regression diagnostics showed no evidence of collinearity, and residual nonnormality and heteroscedasticity in the obtained models.
Correlation Between Invasive Hemodynamic Measurements and Noninvasive Doppler-Derived Variables
Spearman correlation analysis showed a strong correlation (ρ=0.94, P<0.001) between the catheter-measured mitral pressure gradient and Doppler-derived transmitral mean gradient values. There was also a substantial correlation (ρ=0.67, P<0.001) between the catheter-measured systolic PAP and Doppler-derived systolic PAP values.
In this series, the actuarial survival rates at 1, 2, and 3 years after surgery were 95±2%, 92±3%, and 87±4%, respectively. During the follow-up period, there were 6 late cardiac-related deaths, 29 late readmissions due to heart failure, 1 myocardial infarction, and 4 ventricular arrhythmias. Freedom from adverse cardiac events at 1, 2, and 3 years after surgery was 88±3%, 78±4%, and 68±5%, respectively. There was no difference in freedom from adverse cardiac events between patients with an indexed EOA of >1.2 cm2/m2 versus ≤1.2 cm2/m2.
Among the preoperative variables investigated, preoperative PAP >60 mm Hg (HR, 4.5; 95% CI, 2.2 to 8.9) and a history of ventricular arrhythmia (HR 2.1, 95% CI: 1.0 to 4.6) were the predictors of the postoperative adverse cardiac events (Table 6). Furthermore, among the postoperative echocardiographic variables and surgical data, a postoperative PAP >40 mm Hg (HR, 4.6; 95% CI, 2.3 to 9.3) and residual tricuspid regurgitation (HR, 2.5; 95% CI, 1.0 to 6.1) were the predictors of adverse cardiac events (Table 7).
This study constitutes an initial report evaluating the association between iatrogenic functional MS, PPM in terms of in vivo indexed EOA, residual PH, and clinical outcome (late adverse cardiac events) after RMA in patients with advanced cardiomyopathy.
The present echocardiographic results are largely consistent with those presented in previous studies, especially in terms of the transmitral mean gradient, mitral valve area, and systolic PAP.3,4,14–16 In contrast, Magne et al5 reported a higher mean gradient (6±2 mm Hg), smaller mitral valve area (1.5±0.3 cm2), and higher systolic PAP (42±13 mm Hg) values compared with other prior studies. Among the 24 patients in their study, 54% (n=13) had a mean gradient ≥5 mm Hg, 54% (n=13) had a valve area ≤1.5 cm2, and 45% (n=11) had a systolic PAP ≥40 mm Hg. From those findings, they concluded that a large proportion (>50%) of the patients who underwent RMA had moderate functional MS and significant PH after the operation. In addition, a recent study9 also reported a high prevalence (42%) of patients with a small valve area, ≤1.5 cm2. However, in that study, the transmitral gradients were similar to those reported in many other studies.3,4,14–16
In the present study, only 9% of the patients showed a mean gradient ≥5 mm Hg, and none had a valve area ≤1.5 cm2. The contrasting results with regard to valve area as compared to the study of Magne et al5 can be explained by the different methods utilized for determining valve area. Magne et al5 calculated mitral valve area using the continuity equation, whereas many other investigators, including our group, determined it using the pressure half-time method or direct planimetry.3,4,14–16 In addition, the difference in results for the transmitral gradient may be due to subject selection bias or the patient's BSA. The mean BSA of their patients was greater than that of our patients (1.8±0.2 m2 versus 1.65±0.19 m2). Magne et al5 also found a significant correlation between the mitral peak gradient and systolic PAP (r=0.70) and concluded that functional MS after RMA was strongly associated with postoperative elevated PAP and reduced exercise capacity. We found a weak but significant correlation between the mean mitral gradient and systolic PAP, which may support their speculation. However, it remains unknown whether the mitral gradient is the sole factor that affects postoperative elevated PAP.
There have been few hemodynamic studies on possible functional MS after RMA. Our hemodynamic results provide additional information about the gradients across the mitral valve and possible factors relating to postoperative PH. The present study also found a small but significant transmitral pressure gradient, calculated as the pressure difference between mean PCWP and LVEDP, which ranged from 1 to 7 mm Hg. The actual value may be slightly smaller than predicted by this pressure difference.17 Nevertheless, about 10% of our patients (6 of 58) had a pressure gradient ≥5 mm Hg, suggesting the presence of hemodynamically substantial MS. Interestingly, in the present study, we found a strong correlation between the catheter-determined pressure gradient calculated from the mean PCWP and LVEDP, and the Doppler-derived mean gradient. This close correlation allowed us to predict the actual transmitral mean gradient, based on the pressure difference at end-diastole and to analyze relevant factors related to postoperative PH.
Hemodynamic Determinants of Postoperative PAP
Our multivariate analysis using hemodynamic variables showed that the most important determinant of systolic PAP was LVEDP, followed by PVR, and then cardiac index, whereas the contribution of the transmitral pressure gradient was the lowest of the parameters investigated. These findings suggest that the main mechanism of postoperative PH may be high LVEDP, probably due to LV systolic and diastolic dysfunction, whereas another may be pulmonary vascular disease secondary to a preoperative pulmonary hypertensive state. The contribution of a transmitral pressure gradient created by the use of an undersized ring to postoperative PH seemed relatively small in our patients.
Impact of the RMA Procedure on Hemodynamic and Clinical Results
The present patients with a 24-mm ring had a smaller mitral valve area and slightly greater transmitral mean gradient in echocardiographic findings, as well as a greater valve gradient in the hemodynamic evaluation, compared with those with a 26-mm ring. Despite these differences in mitral valve performance, there were no differences between the 2 groups in regard to postoperative LV volume and systolic function, PAPs, or the other measured hemodynamic parameters. Thus, in our patients, who had a lower BSA compared with those in previous studies, the use of a small prosthetic ring (24-mm Physio ring) did not appear to have a negative influence on the postoperative hemodynamic state over the short term.
Given that the normal mitral valve area is 4.0 to 5.0 cm2, the 24- and 26-mm rings have obviously smaller orifice areas and are at least mildly obstructive to the antegrade mitral flow. The severity of this PPM can be categorized as mild, moderate, or severe according to the “in vivo” EOA indexed for the patient's BSA, as in previous studies.7,8 Several studies have demonstrated that after mitral valve replacement, moderate PPM (indexed EOA ≤1.2 cm2/m2) is not uncommon, and that it has negative impacts on postoperative residual PH and late mortality and morbidity.7,8,18 Other authors have suggested that moderate PPM in these patients is of less importance.19,20
In contrast, the prevalence and prognostic impact of PPM after RMA has not been well established. Our data showed that, following RMA, a considerable proportion (>20%) of patients had PPM, defined as an indexed EOA ≤1.2 cm2/m2. This mismatch occurred in 27% of the patients with a 24-mm ring and 12% with a 26-mm ring, which was not statistically different. Given that the pressure half-time method may overestimate the actual valve orifice area by about 10%, our in vivo EOA values suggest that the size 24- and 26-mm prosthetic rings may be too small, respectively, for patients with a BSA >1.75 to 1.80 m2 or >1.90 to 2.00 m2. However, it remains unclear whether such a mismatch after RMA has a negative impact on patient's prognosis.
In the present study, preoperative and postoperative residual PH, due to LV dysfunction and secondary pulmonary vascular disease, was more strongly associated with adverse cardiac events after RMA than was the severity of functional MS or the level of PPM. A Doppler-derived mean gradient of ≥5 mm Hg or an indexed EOA of ≤1.2 cm2/m2 did not predict adverse cardiac events during our short-term follow-up. We speculate that our identification of a negative prognostic role (a higher risk of adverse cardiac events) of this iatrogenic MS would have been masked in our analysis by the more important risk factors.
The main limitation of this study is its retrospective design, as hemodynamic data could not be obtained from all of the patients, which may have resulted in a bias and restrict the statistical power of the findings. Also, in fully describing these data we have performed a large number of statistical tests, inflating the probability of making one or more type I errors across all the analyses presented. Therefore, our results should be interpreted cautiously until verified in an independent, prospective study. Furthermore, simultaneous LA and LV pressure tracings were not available, and therefore the actual mean transmitral pressure gradients and mitral valve EOA could not be determined using the Gorlin formula. In our echocardiographic and hemodynamic evaluations, the parameters were measured only in a resting condition; a dynamic exercise test with a bicycle ergometer, dobutamine stress test, or 6-minute walk test was not performed. However, data obtained from those stress tests would not have changed our conclusion. Finally, we only investigated patients who received a 24- or 26-mm Physio ring. Therefore, the results may not be applicable to patients who receive a different size or type of ring.
In the present study, the RMA procedure led to varying degrees of mitral valve obstruction in terms of higher transmitral mean pressure gradients (about 9% of patients) and a lesser EOA, as indexed for each patient's BSA (>20% of patients). This hemodynamic sequel was weakly associated with postoperative residual PH. However, postoperative elevated PAP was strongly associated with an elevated LVEDP and increased PVR. PH caused by LV dysfunction and pulmonary vascular disease was the most important predictor for outcomes in this study. The prognostic impact of iatrogenic MS after RMA would be hard to detect because of masking by more important risk factors.
Sources of Funding
This study was partially supported by research funds to promote the hospital function of Japan Labor Health and Welfare Organization.
- © 2011 American Heart Association, Inc.
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