Abstract
Background
Permanent pacemaker (PPM) placement after mitral valve (MV) repair is affected by concomitant procedures, yet existing literature reports conflicting rates. We aimed to characterize the effect of concomitant operation on risk of need for postoperative PPM in patients who underwent MV repair.
Methods
A retrospective review of a prospectively maintained institutional database (1996-2020) was conducted of consecutive patients undergoing MV repair, including concomitant procedures. Multivariable regression analysis was performed to evaluate the effect of a concomitant procedure on PPM rate.
Results
Of the 2824 patients undergoing MV repair, 6% (177/2824) required a PPM. The likelihood of PPM varied with concomitant procedures: aortic valve replacement (39/258 [15%]), coronary artery bypass grafting (86/789 [11%]), tricuspid valve (TV) repair (33/326 [10%]), and maze (27/407 [7%]). Increased PPM rate was associated with aortic valve replacement (odds ratio [OR], 2.2 [1.5-3.3]; P < .001), reduced ejection fraction (OR, 1.02 [1.01-1.04]; P < .001), and older age (OR, 1.04 [1.03-1.06]; P < .001). Concurrent TV repair was not associated with pacemaker in patients undergoing MV repair (P = .8) or MV repair for nondegenerative mitral regurgitation (P = .9). In patients with degenerative MV disease, PPM rate increased from 1.9% (21/1133) to 10% (11/109) with concomitant TV repair (P < .001), and TV repair was associated with a 3-fold increased pacemaker rate (OR, 3.1 [1.6-5.9]; P < .001).
Conclusions
In MV repair, risk of pacemaker with concomitant TV repair should be weighed more heavily in degenerative MV disease. Pacemaker risk should not discourage surgeons from performing TV repair in patients with nondegenerative MV disease, in patients already undergoing concomitant operation or with clinically significant tricuspid regurgitation.
In Short.
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Permanent pacemaker rate after mitral valve (MV) repair increased with concomitant aortic valve replacement (15%), coronary artery bypass grafting (11%), and tricuspid valve (TV) repair (10%) compared with isolated MV repair (3%).
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Concurrent TV repair was not associated with pacemaker after any MV repair (P = .8) or MV repair for nondegenerative mitral regurgitation (P = .9); however, degenerative mitral regurgitation demonstrated 3-fold increased pacemaker rate (odds ratio, 3.1; P < .001).
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In MV repair, pacemaker risk with TV repair should be weighed more heavily in degenerative mitral disease.
Untreated tricuspid regurgitation (TR) is associated with worsened long-term survival, and tricuspid valve (TV) operation at the time of left-sided operation has demonstrated improved survival with >90% at 5 years.1,2 Guidelines recommend TV operation at the time of left-sided valve operation, in progressive and severe TR.3 However, TV operation is associated with need for a permanent pacemaker (PPM) postoperatively in patients undergoing left-sided valve operation, and PPM is associated with decreased long-term survival or increased TR.4, 5, 6 The Cardiothoracic Surgical Trials Network randomized controlled trial demonstrated that in patients with degenerative mitral valve (MV) disease and moderate TR, TV repair during MV repair increased the incidence of new PPM from 2.5% to 14% (rate ratio, 5.75; 95% CI, 2.27-14.60).4 The increased risk of PPM may discourage concurrent TV repair during MV repair.7 The controversy is magnified by conflicting and insufficient data on the association or causation of TV operation in MV operation versus other variables, including atrial fibrillation and cardiomyopathy, that may be independently linked to TR.
The aim of this study was to further investigate the effect of concomitant valve operation in patients undergoing MV repair on postoperative need for PPM.
Patients and Methods
A prospectively maintained institutional database was used to identify consecutive patients undergoing MV operation for mitral regurgitation (MR) between January 1997 and December 2020. Concurrent valve operation, coronary artery bypass grafting (CABG), and maze procedure were included.
Our primary end point was need for PPM postoperatively during the index hospitalization. Normally distributed continuous data were presented as means ± SD. Skewed data were presented with median and interquartile range. Cumulative incidence curves were compared by Gray test. Binary outcomes were compared with Pearson χ2 or Fisher test as appropriate and presented as frequency counts and percentages. Continuous outcomes were compared with Wilcoxon rank sum test or t-test as appropriate and summarized with mean ± SD or median and interquartile range. The independent association between preoperative and intraoperative covariates and need for PPM was evaluated by multivariable logistic regression modeling. Correlates of patient survival were examined with Cox proportional hazards analysis.
Statistical software was SAS 9.4 (SAS Institute). Waiver of informed consent was approved by the IRB (Pro00105933, approved June 22, 2020).
Results
From 1997 to 2020, a consecutive 2824 patients underwent MV operation and 6% (177/2824) required PPM. Causes of MV disease included degenerative (1436 [51%]), ischemic (737 [26%]), nonischemic functional (306 [11%]), infectious (133 [5%]), and other (212 [8%]). Isolated MV repair was performed in 56% (1577) of patients. Overall, repair techniques included leaflet resection (527/2824 [19%]), chordal replacement (775/2824 [27%]), partial band (95/2824 [3%]), and complete rigid or semirigid ring (2729/2824 [97%]). Concurrent procedures included CABG (789 [28%]), maze (407 [14%]), TV repair (326 [12%]), and aortic valve replacement (258 [9%]).
Patients who received PPM were older (68 years vs 61 years), with a lower ejection fraction (42% vs 47%), and were more likely to have a history of atrial fibrillation (36% vs 28%) and coronary artery disease (55% vs 34%; Table 1). The median time to PPM insertion was 7 (5-9) days. Indications for PPM were complete heart block (38% [64/167]), junctional bradycardia (33% [55/167]), and ventricular arrhythmia (29% [48/167]). PPM placement was associated with increased length of stay (median, 11 days vs 6 days; P < .001). The concomitant procedures most likely to need PPM were TV repair (33/326 [10%]) and aortic valve replacement (39/258 [15%]). For patients with degenerative disease undergoing only MV repair, addition of TV repair significantly increased the PPM rate from 21 of 1133 (1.9%) without TV repair to 11 of 109 (10%) with TV repair (P < .001; Table 2). For nondegenerative MV disease, the pacemaker rate was not affected by concurrent TV repair (Table 2).
Table 1.
Preoperative and Intraoperative Data
| Variable | Pacemaker |
P Value | |
|---|---|---|---|
| Yes (n = 177) | No (n = 2647) | ||
| Age, y | 68 ± 10 | 61 ± 13 | <.001 |
| Male | 108 (61) | 1604 (61) | .9 |
| White | 133 (75) | 2110 (80) | .2 |
| Ejection fraction, % | 42 ± 14 | 47 ± 13 | <.001 |
| Lung disease | 37 (21) | 317 (12) | .001 |
| Atrial fibrillation | 63 (36) | 734 (28) | .02 |
| Coronary artery disease | 98 (55) | 903 (34) | <.001 |
| Urgent | 56 (32) | 581 (22) | .003 |
| Severe MR | 143 (81) | 2364 (89) | .001 |
| Severe TR | 34 (19) | 374 (14) | .06 |
| Degenerative MR | 52 (29) | 1384 (52) | <.001 |
| Redo sternotomy | 24 (8) | 262 (10) | .11 |
Categorical variables are presented as number (percentage). Continuous variables are presented as mean ± SD.
MR, mitral regurgitation; TR, tricuspid regurgitation.
Table 2.
Pacemaker Rate by Operation
| Operation | Overall Pacemaker Rate | TV Repair |
P Value | |
|---|---|---|---|---|
| No | Yes | |||
| Overall | 177/2824 (6) | 144/2498 (6) | 33/326 (10) | .002 |
| Isolated MV repair ± TV repair | 61/1788 (3) | 45/1577 (3) | 16/211 (8) | .001 |
| Isolated MV repair | ||||
| Nondegenerative | 29/546 (5) | 24/444 (5) | 5/102 (5) | .8 |
| Degenerative | 32/1242 (2.5) | 21/1133 (1.9) | 11/109 (10) | <.001 |
| MV repair + AVR | 39/258 (15) | 34/218 (16) | 5/40 (13) | .40 |
| MV repair + CABG | 86/789 (11) | 72/709 (10) | 14/80 (18) | .09 |
| MV repair + maze | 27/407 (7) | 19/333 (6) | 8/74 (11) | .10 |
Values are reported as n/N (%).
AVR, aortic valve replacement; CABG, coronary artery bypass grafting; MV, mitral valve; TV, tricuspid valve.
In the multivariable analysis of all patients, need for PPM was associated with aortic valve replacement (odds ratio [OR], 2.2 [1.5-3.3]; P < .001), age (OR, 1.04 [1.03-1.06]; P < .001), and reduced ejection fraction (OR, 1.02 [1.01-1.04]; P < .001; Table 3). Severity of preoperative TR and concomitant maze were not associated with need for PPM. MV repair technique (resection vs chordal replacement), mitral ring size, tricuspid ring size, and mitral ring vs band did not affect PPM requirement. Concurrent TV repair was not associated with PPM requirement for all patients (P = .8) or patients with nondegenerative MR (P = .9) but did have a significant interaction with cause of degenerative MV disease (P = .002). In multivariable analysis of a subgroup of patients with degenerative MV disease, need for PPM was associated with older age (OR, 1.08 [1.05-1.11]; P < .001) and TV repair (OR, 3.1 [1.6-5.9]; P < .001; Table 3).
Table 3.
Multivariable Analysis of Need for New Permanent Pacemaker
| Variable | Odds Ratio | P Value |
|---|---|---|
| All patients | ||
| Age | 1.04 (1.03-1.06) | <.001 |
| Reduced ejection fraction | 1.02 (1.01-1.04) | <.001 |
| Aortic valve replacement | 2.2 (1.5-3.3) | <.001 |
| Degenerative mitral disease | ||
| Age | 1.08 (1.05-1.11) | <.001 |
| Tricuspid valve repair | 3.1 (1.6-5.9) | <.001 |
Operative mortality was similar in patients with and without postoperative PPM (4/177 [2%] vs 77/2647 [3%]; P = .6). Whereas patients requiring PPM demonstrated lower absolute 10-year survival (33% ± 4% vs 61% ± 1%; P < .001; Figure), PPM was not associated with long-term survival by Cox proportional hazards analysis (P = .06).
Figure.
After mitral valve repair, survival was higher in patients who did not receive postoperative pacemaker (no pacemaker) compared with patients who required new postoperative pacemaker (pacemaker; P < .001).
Comment
In patients undergoing MV operation for MR, postoperative implantation of a PPM is associated with concomitant procedures and MV disease cause. The addition of aortic valve replacement to MV repair for degenerative or functional disease is associated with a 2-fold increase (OR, 2.2 [1.5-3.3]) in PPM. In patients undergoing MV repair for degenerative disease, PPM rate increased from 1.9% to 10% with the addition of TV repair (P < .001). Patients with degenerative MV disease and concurrent TV repair experienced a 3-fold increase in PPM (OR, 3.1 [1.6-5.9]).
Our study highlights that variation in PPM rates after MV repair may be due to concomitant procedures in addition to patient characteristics such as age, aortic valve disease, ejection fraction, and MV disease cause. The incidence of new pacemaker placement after MV repair for degenerative disease with concomitant TV repair varies widely in the literature from 2.4% (10/419) in a single-surgeon study to 14% in the Cardiothoracic Surgical Trials Network randomized controlled trial.4,8 Furthermore, the predictors of pacemaker requirements after MV repair are not well established. Interestingly, in a retrospective review of The Society of Thoracic Surgeons adult cardiac surgery registry data, patients undergoing MV repair or replacement for any MV disease also demonstrated a wide incidence of PPM; patients with and without TV repair had a PPM incidence of 14.7% (1258/8558) and 5.4% (2621/48,540), respectively.9 Lower rates were seen with degenerative MV disease, and higher rates were reported for ischemic MR.
This study has important implications for the relative indications of and contraindications to TV repair at the time of MV repair. For patients with nondegenerative MV disease or patients undergoing concomitant aortic valve replacement, CABG, or maze, the addition of TV repair has no significant effect on the pacemaker rate. Therefore, risk of PPM should not be a deterrent to TV repair. Conversely, in patients with degenerative MV disease who have a relatively low baseline risk for pacemaker (1.9% in this series), the risk of pacemaker placement with concurrent TV repair increases 3-fold. The risk to benefit ratio in this population of variable patients is challenging as the entire risk profile is incompletely characterized in the literature. However, evidence highlights the 2-fold increased mortality in patients with moderate and severe TR and increased heart failure hospitalization (risk ratio, 1.73 [1.14-2.62]) compared with no or mild TR (risk ratio, 1.95 [1.75-2.17]).1 In patients presenting with severe TR undergoing left-sided valve operation, TV operation is recommended in consensus guidelines.3 However, in patients presenting with less than severe TR, the data and guidelines are less consistent.10 For each clinical scenario, surgeons must reconcile patient factors with the risk of persistent TR and the risk of pacemaker.7
Limitations
Our study is a retrospective analysis from a single center during 23 years. The use of logistic regression cannot entirely adjust for selection bias for surgical approach or surgeon preference. Patient characteristics and institutional volume may vary between institutions. In addition, the proportion of patients with functional MV disease, who typically receive complete rigid rings, has changed during the study period.
Conclusion
For patients undergoing MV repair, PPM rate increased with concomitant procedures compared with isolated MV repair. Concurrent TV repair was not associated with pacemaker in patients undergoing any MV repair or MV repair for nondegenerative MR. However, degenerative MR demonstrated 3-fold increased pacemaker rate. Therefore, the risk of pacemaker with concomitant TV repair should be weighed more heavily in degenerative MV disease. Pacemaker risk should not discourage surgeons from performing TV repair in patients with nondegenerative MV disease, in patients already undergoing concomitant operation, or with clinically significant TR.
Acknowledgments
Funding Sources
The authors have no funding sources to disclose.
Disclosures
The authors have no conflicts of interest to disclose.
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