Abstract
Objective
The study objective was to provide evidence for choosing a bioprosthesis in treating patients with active aortic valve endocarditis.
Methods
From 1998 to 2017, 265 patients with active aortic valve endocarditis underwent aortic valve replacement with a stented valve (n = 97, 37%) or a stentless valve (n = 168, 63%) with further breakdown into inclusion technique (n = 142, 85%) or total root replacement (n = 26, 15%). Data were obtained from the Society of Thoracic Surgeons database aided with chart review, surveys, and National Death Index data.
Results
The median age of patients was 53 years (43–56) in the stented group and 57 years (44–66) in the stentless group. The stented and stentless groups had high rates of heart failure (54% and 40%), liver disease (16% and 7.7%), prosthetic valve endocarditis (14% and 48%), root abscess (38% and 70%), and concomitant ascending aorta procedures (6.2% and 22%), respectively. The stentless group required permanent pacemakers in 11% of cases. Operative mortality was similar between groups (6.2% and 7.1%). The 5-year survival was 52% and 63% in the stented and stentless groups, respectively. Significant risk factors for long-term mortality included liver disease (hazard ratio, 2.38), previous myocardial infarction (hazard ratio, 1.64), congestive heart failure (hazard ratio, 1.63), and renal failure requiring dialysis (hazard ratio, 4.37). The 10-year cumulative incidence of reoperation was 12% and 3.4% for the stented and stentless groups, respectively. The 10-year freedom from reoccurrence of aortic valve endocarditis was 88% for the stented and 98% for the stentless groups.
Conclusions
Both stented and stentless aortic valves are appropriate conduits for replacement of active aortic valve endocarditis for select patients.
Keywords: aortic valve replacement, endocarditis, stented aortic valve, stentless aortic valve
Graphical Abstract
The treatment of aortic valve endocarditis (AVE) varies widely because of multiple factors, including the extent of infection, whether it is a native valve versus prosthetic valve infection, or simply surgeon preference. Surgically, the use of homografts has been the dogma for aortic valve replacement (AVR) because of their unrivaled biocompatibility and reduced risk of reinfection.1,2 Although their use continues to be widespread because of the reconstructive capability of the aortic root in complicated AVE,3,4 homografts also have multiple limitations such as limited availability, increased complexity of reoperation, higher propensity of calcification, and increased risk of infectious transfer between donor and recipient.5,6 Notably, homografts have also been associated with high rates of structural valve degeneration (SVD).7,8 As such, other bioprostheses have gained popularity, particularly with studies demonstrating resistance to infection6 and late mortality9 similar to homografts.
In terms of bioprostheses, the current literature on stentless and stented AVRs for active AVE varies. Stented valves have shown adequate results in patients with native valve endocarditis and prosthetic valve endocarditis (PVE).10 Likewise, Freestyle stentless bioprosthetic valves have shown success in patients with infective AVE with local aortic root destruction.11 Stentless aortic valves have also shown improved hemodynamics, which enhances survival compared with stented aortic valves.12,13 Conversely, other studies have found stentless valves to be inferior to stented valves because of increased structural valve deterioration and the occurrence of PVE.14 Stentless and stented aortic valves have even been reported as equivalent, demonstrating an inconsistency in findings.15 As such, this study aims to provide additional data to allow surgeons to make an informed decision with a study that has a larger sample size. We hypothesized that both stented and stentless bioprostheses would provide similar outcomes in the treatment of AVE.
MATERIALS AND METHODS
This study was approved by the Institutional Review Board at Michigan Medicine (HUM00142927; March 31, 2019), and a waiver of informed consent was obtained.
Patient Selection and Data Collection
Between December 1998 and December 2017, 299 patients with active AVE underwent an AVR at a single institution. Thirty-four patients who underwent homograft replacement were excluded from the study because homografts were used in the early period of the study time. Of the 265 patients included, 97 (37%) received a stented aortic valve and 168 (67%) received a stentless AVR. Investigators retrospectively obtained data through the Society of Thoracic Surgery from Michigan Medicine’s Cardiac Surgery Data Warehouse to identify the cohort and obtain preoperative, operative, and postoperative variables. These data were supplemented with a retrospective medical record review by the study team.
Survival and reoperation data were collected by medical record review and supplemented with surveys (including letters and phone calls) and National Death Index data through December 31, 2018.16 The end of the study period was on October 1, 2019. Primary outcomes were defined as postoperative outcomes and long-term survival.
Operative Technique
Our indications for surgery were based on the American Association for Thoracic Surgery infective endocarditis guidelines.17 We generally operate on patients with endocarditis with (1) new symptomatic valve dysfunction; (2) left-sided endocarditis if causative organism is Staphylococcus aureus, fungal, or other highly resistant organisms; (3) heart block or destructive annular or root lesion with or without conduction abnormalities; and (4) persistent bacteremia despite adequate antimicrobial therapy. In patients with infected aortic valves that could not be repaired, an AVR was performed. Radical debridement of infected tissue was essential in preparation for valve implantation. In patients without root abscess, the infected leaflets or prosthetic valve was removed, and the root was extensively debrided. Any defect of the aortic root was patched with autologous pericardium or bovine pericardium if needed. Routine AVR was completed with a stented or stentless aortic bioprosthesis.18,19
In patients with root abscess, if the cavity involved less than one-third (one sinus) of the aortic annulus, the cavity was patched with autologous pericardium or bovine pericardium followed by the AVR. If the abscess involved greater than one-third (2 sinuses) of the aortic annulus, then either a total root replacement with separate reimplantation of the 2 coronary buttons or patch repair of the cavity and modified inclusion aortic root repair was completed. Techniques were chosen on the basis of surgeon’s preference. When we used the modified inclusion technique, we debrided the abscess thoroughly and patched the abscess with a bovine/autologous pericardium first to separate the stentless valve from infected area. For patients with root abscess and a destroyed aorto-mitral curtain, we directly anastomosed the stentless valve to the mitral valve annulus and muscular septum after extensive debridement and then reimplanted 2 coronary buttons. We previously patched the abscess cavity and performed a modified inclusion root replacement with a stentless valve. In the most recent cases, we performed total root replacement (Bentall procedure) without patching. We have been using an autologous pericardial patch lately, even in redo operations.
Statistical Analysis
Data are presented as median (25%, 75%) for continuous data and n (%) for categoric data. Because of the difference between the 2 groups, we are reporting descriptive outcomes of treatment of AVE with stented and stentless valves. Multivariable logistic regression (C statistic, 0.806) was used to calculate the odds ratio (OR) of risk factors for operative mortality by adjusting for the group, age, liver disease, and previous aortic valve procedure. The Cox proportional hazards regression model (C statistic, 0.688) was used to calculate the adjusted hazard ratios (HRs) for mortality since surgery, adjusting for the group, age, liver disease, previous myocardial infarction (MI), congestive heart failure (CHF), renal failure requiring dialysis, and intravenous (IV) drug abuse. The variables selected for the logistic model and the Cox model were selected by automatic model stepwise selection. The Kaplan–Meier method was used to estimate survival curves and freedom from reinfection with the log-rank test for all patients. Completeness of follow-up was calculated by the ratio of the sum of the observed follow-up time to the sum of the potential follow-up time.20 Cumulative incidence function curves were adjusted for death as a competing risk using the Fine and Gray subdistribution method to assess the incidence of reoperation over time. Statistical calculations were performed using SAS (SAS Institute, Inc, Cary, NC).
RESULTS
Demographic and Preoperative Data
Both groups had a similar median age: 53 years (43–66) in the stented group and 57 years (44–66) in the stentless group. There were also similar rates of coronary artery disease, diabetes, hypertension, and smoking status. Of the patients in the stented group, 16% had a history of MI, 54% had CHF, 28% had a history of stroke, 16% had liver disease, 18% had a prior valve surgery, and 14% had PVE. Of the patients in the stentless group, 20% had a history of MI, 40% had CHF, 14% had a history of stroke, 7.7% had liver disease, 52% had a prior valve replacement, and 48% had PVE (Table 1).
TABLE 1.
Preoperative and demographic data
| Variable | Stented (n = 97) | Stentless (n = 168) |
|---|---|---|
| Age (median), y | 53 (43–66) | 57 (44–66) |
| Sex (female) | 25 (26) | 29 (17) |
| CAD | 20 (21) | 35 (21) |
| Diabetes | 23 (24) | 41 (24) |
| Dyslipidemia | 35 (36) | 75 (45) |
| Hypertension | 58 (60) | 110 (65) |
| PVE | 14 (14) | 79 (48) |
| Previous AVR | 14 (14) | 68 (40) |
| Previous ARR | 0 (0) | 11 (6.5) |
| History of endocarditis | 18 (19) | 35 (21) |
| Tobacco use | ||
| Nonsmoker | 50 (52) | 88 (52) |
| Former smoker | 22 (23) | 31 (18) |
| Current smoker | 25 (26) | 49 (29) |
| Lung disease | ||
| None | 78 (80) | 143 (85) |
| Mild | 10 (10) | 14 (8.3) |
| Moderate | 4 (4.1) | 4 (2.4) |
| Severe | 5 (5.2) | 7 (4.2) |
| Pneumonia | 13 (13) | 13 (7.7) |
| IV drug abuse | 19 (20) | 22 (13) |
| Depression | 17 (18) | 15 (8.9) |
| Alcohol | ||
| None | 47 (48) | 95 (57) |
| <1 drink/wk | 31 (32) | 35 (21) |
| 2–7 drinks/wk | 9 (9.3) | 16 (9.5) |
| >8 drinks/wk | 7 (7.2) | 12 (7.1) |
| Unknown | 3 (3.1) | 10 (6.0) |
| Liver disease | 16 (16) | 13 (7.7) |
| Prior MI | 16 (16) | 34 (20) |
| CHF | 52 (54) | 68 (40) |
| Stroke | 27 (28) | 24 (14) |
| Sepsis | 19 (20) | 20 (12) |
| Cardiogenic shock | 9 (9.3) | 11 (6.6) |
| Arrhythmia | 12 (12) | 31 (18) |
| Previous CABG | 8 (8.3) | 22 (13) |
| Previous valve surgery | 17 (18) | 87 (52) |
| Previous aortic valve repair | 0 (0) | 1 (0.6) |
| Previous ascending aorta procedure | 3 (3.1) | 9 (5.4) |
| Previous aortic arch procedure | 0 (0) | 2 (1.2) |
Data presented as median (interquartile range) for continuous variables and number (percentage) for categoric variables. CAD, Coronary artery disease; PVE, prosthetic valve endocarditis; AVR, aortic valve replacement; ARR, aortic root replacement; IV, intravenous; MI, myocardial infarction; CHF, congestive heart failure; CABG, coronary artery bypass graft.
Intraoperative Data
Of patients in the stented group, 38% had a root abscess, 26% had aortic stenosis, and 62% had severe aortic regurgitation. In terms of concomitant procedures, 45% of patients underwent a mitral valve procedure, 20% underwent a tricuspid valve procedure, and 6.2% underwent an ascending aorta procedure in the stented group. Of patients in the stentless group, 70% had a root abscess, 39% had aortic stenosis, and 48% had severe aortic regurgitation. In terms of concomitant procedures, all patients underwent an aortic root procedure, 28% of patients underwent a mitral valve procedure, 15% underwent a tricuspid valve procedure, and 22% underwent an ascending aorta procedure in the stentless group. In the whole cohort, 108 patients underwent aortic root or left ventricular outflow tract pericardial patch reconstruction. The stented and stentless groups had cardiopulmonary bypass times of 165 (125–228) and 247 (194, 298) minutes and crossclamp times of 129 (101–171) and 202 (155–243) minutes, respectively. (Table 2).
TABLE 2.
Operative data
| Variable | Stented (n = 97) | Stentless (n = 168) |
|---|---|---|
| Causative microorganism | ||
| Staphylococci | ||
| Staphylococcus aureus | 17 (18) | 30 (18) |
| Coagulase-negative staphylococci | 9 (9.3) | 29 (17) |
| Enterococci | 22 (23) | 27 (16) |
| Streptococci | 27 (28) | 56 (33) |
| Gram-negative rods | 5 (5.2) | 8 (4.8) |
| Culture negative | 9 (9.3) | 12 (7.1) |
| Fungal | 5 (5.2) | 6 (3.6) |
| Multiple | 1 (1.0) | 1 (0.1) |
| Others | 2 (2.1) | 3 (1.8) |
| Aortic insufficiency | ||
| None | 7 (7.2) | 35 (21) |
| Trivial/trace/minimal | 2 (2.1) | 10 (6.0) |
| Mild | 12 (12) | 17 (10) |
| Moderate | 16 (16) | 26 (15) |
| Severe | 60 (62) | 80 (48) |
| Aortic stenosis | 25 (26) | 65 (39) |
| BAV | 18 (19) | 28 (17) |
| Calcified valve leaflets | 11 (11) | 19 (11) |
| Root abscess | 37 (38) | 117 (70) |
| Aortic root aneurysm | 0 (0) | 7 (4.2) |
| Ascending aorta aneurysm | 6 (6.2) | 12 (7.1) |
| Aortic arch aneurysm | 0 (0) | 2 (1.2) |
| Pseudoaneurysm | 1 (1.0) | 6 (3.6) |
| Incidence | ||
| First cardiovascular surgery | 77 (79) | 79 (47) |
| Second cardiovascular surgery | 18 (19) | 70 (42) |
| Third cardiovascular surgery | 2 (2.1) | 14 (8.3) |
| Fourth cardiovascular surgery | 0 (0) | 2 (1.2) |
| Fifth or more cardiovascular surgery | 0 (0) | 3 (1.8) |
| Status | ||
| Elective | 14 (14) | 13 (7.7) |
| Urgent | 72 (74) | 130 (77) |
| Emergent | 11 (11) | 25 (15) |
| Circulatory arrest | 1 (1.0) | 13 (7.7) |
| Concomitant procedures | ||
| Patch reconstruction | 32 (33) | 76 (45) |
| Root/annular | 31 (32) | 25 (15) |
| LVOT | 1 (1.0) | 47 (28) |
| Both | 0 (0) | 4 (2.4) |
| CABG | 11 (11) | 15 (8.9) |
| Mitral valve procedure | 43 (45) | 44 (28) |
| Tricuspid valve procedure | 19 (20) | 25 (15) |
| Aortic root procedure | 0 (0) | 168 (100) |
| Ascending aorta procedure | 6 (6.2) | 37 (22) |
| Aortic hemi arch procedure | 0 (0) | 4 (2.4) |
| Aortic total arch procedure | 0 (0) | 1 (0.6) |
| CPB time (min) | 165 (125, 228) | 247 (194, 298) |
| Crossclamp time (min) | 129 (101, 171) | 202 (155, 243) |
| Red blood cell units | 2 (1, 4) | 4 (2, 6) |
Data presented as median (interquartile range) for continuous variables and number (percentage) for categorical variables. Other causative microorganisms consist of organisms with positive blood cultures not otherwise categorized. BAV, Bicuspid aortic valve; LVOT, left ventricular outflow tract; CABG, coronary artery bypass graft; CPB, cardiopulmonary bypass.
Perioperative Outcomes
The stentless group required more permanent devices for rhythm disturbance in 14% of cases, including permanent pacemakers in 11% and implantable cardioverter defibrillators in 3%. Postoperative stroke, renal failure, cardiac arrest, in-hospital mortality, 30-day mortality, and operative mortality (6.2% in stented group and 7.1% in stentless group) were low in both groups (Table 3). Significant risk factors for operative mortality identified by multivariate logistic analysis included liver disease (OR, 6.88) and previous aortic valve procedure (OR, 3.01) (Table 4).
TABLE 3.
Postoperative data
| Variable | Stented (n = 97) | Stentless (n = 168) |
|---|---|---|
| Thoracotomy | 1 (1.0) | 0 (0) |
| Reoperation for bleeding/tamponade | 6 (6.2) | 5 (3.0) |
| Planned closure delay | 2 (2.1) | 3 (1.8) |
| Sternal dehiscence | 0 (0) | 1 (0.6) |
| Postoperative red blood cell units | 2 (0, 3) | 2 (0, 4) |
| Ventilation, h | 13 (5.0–24) | 13.4 (3.8–42) |
| Prolonged ventilation | 24 (25) | 56 (33) |
| Pneumonia | 7 (7.2) | 12 (7.1) |
| Sepsis | 4 (4.1) | 4 (2.4) |
| Positive blood cultures | 4 (4.1) | 3 (1.8) |
| Stroke | 1 (1.0) | 3 (1.8) |
| Paralysis | 1 (1.0) | 0 (0) |
| ICU stay (d) | 3.0 (1.7, 6.1) | 2.9 (0, 7.8) |
| New-onset dialysis | 8 (8.3) | 10 (6.0) |
| Device | 3 (3.1) | 24 (14) |
| Pacemaker | 3 (3.1) | 19 (11) |
| ICD | 0 (0) | 5 (3) |
| Cardiac arrest | 2 (2.1) | 6 (3.6) |
| Multisystem organ failure | 0 (0) | 3 (1.8) |
| GI event | 9 (9.3) | 14 (8.3) |
| Atrial fibrillation | 28 (29) | 44 (26) |
| In-hospital mortality | 6 (6.2) | 11 (6.6) |
| 30-d mortality | 4 (4.1) | 10 (6.0) |
| Intraoperative mortality | 1 (1.0) | 3 (1.8) |
| Operative mortality* | 6 (6.2) | 12 (7.1) |
Data presented as median (interquartile range) for continuous variables and number (percentage) for categoric variables. ICU, Intensive care unit; ICD, implantable cardioverter defibrillator; GI, gastrointestinal.
Operative mortality is based on the Society of Thoracic Surgeons definition and includes all deaths, regardless of cause, occurring during the hospitalization in which the operation was performed, even if after 30 days (including patients transferred to other acute care facilities); and all deaths, regardless of cause, occurring after discharge from the hospital, but before postoperative day 30.
TABLE 4.
Logistic model for the risk factor of operative mortality
| Variable | Odds ratio | P value |
|---|---|---|
| Stented aortic valve | 0.87 (0.29–2.59) | .80 |
| Age | 1.00 (0.96–1.03) | .81 |
| Liver disease | 6.88 (2.34–20.2) | .0005 |
| Previous aortic valve procedure | 3.01 (1.08–8.33) | .03 |
Long-Term Outcomes
The median follow-up time was 4.0 (1.7–7.3) years with 99.9% follow-up completeness. A total of 48 patients (49%) in the stented group and 74 patients (44%) in the stentless group died during follow-up (Table E1). The 5-year survival was 52% (95% confidence interval [CI], 40–62) in the stented group and 63% (95% CI, 55–71) in the stentless group (Figure 1). The significant risk factors for all-time mortality include age (HR, 1.02), liver disease (HR, 2.38), previous MI (HR, 1.64), CHF (HR, 1.63), and renal failure requiring dialysis (HR, 4.37) (Table 5).
TABLE E1.
Long-term outcomes
| Variable | Stented (n = 97) | Stentless (n = 168) |
|---|---|---|
| Reoperation reason | ||
| SVD | 3 (3.1) | 6 (3.6) |
| PVE | 3 (3.1) | 1 (0.6) |
| Death | 48 (49) | 74 (44) |
SVD, Structural valve deterioration; PVE, prosthetic valve endocarditis.
FIGURE 1.
Kaplan–Meier long-term survival of patients with AVE with a stented AVR (5 years: 52%; 95% CI, 40–62) or a stentless AVR (5 years: 63%; 95% CI, 55–71).
TABLE 5.
Cox proportional hazard regression for late mortality
| Variable | Hazard ratio | P value |
|---|---|---|
| Stented aortic valve | 1.18 (0.81–1.71) | .40 |
| Age | 1.02 (1.00–1.03) | .03 |
| Liver disease | 2.38 (1.33–4.25) | .004 |
| Previous MI | 1.64 (1.07–2.54) | .02 |
| CHF | 1.63 (1.13–2.36) | .01 |
| Renal failure requiring dialysis | 4.37 (2.49–7.67) | <.0001 |
| IV drug abuse | 1.35 (0.77–2.37) | .29 |
MI, Myocardial infarction; CHF, congestive heart failure; IV, intravenous.
The 10-year postoperative cumulative incidence of reoperation was 12% in the stented aortic valve group and 3.4% in the stentless aortic valve group (Figure 2). A total of 13 patients had a reoperation, 6 patients in the stented and 7 patients in the stentless group. The indications for reoperation for the stented valve group and the stentless valve group were SVD (3.1% and 3.6%) and PVE (3.1% and 0.6%) (Tables E1 and E2). The 10-year freedom from reoccurrence of AVE was 88% for the stented valve group and 98% for the stentless valve group (Figure 3).
FIGURE 2.
Cumulative incidence of reoperation adjusting for death as a competing factor in patients with AVE treated with stented AVR (10 years: 12%; 95% CI, 4.1–25) or a stentless AVR (10-years: 3.4%; 95% CI, 0.8–9.1).
TABLE E2.
Reoperation information
| Group | Time to reoperation (y) | Reason for reoperation | Reoperative procedures |
|---|---|---|---|
| Stented | 0.16 | SVD | Redo repair of prosthetic aortic valve |
| Stented | 0.37 | PVE | Redo aortic root replacement, mitral valve repair, tricuspid valve repair |
| Stentless | 0.98 | PVE | Redo aortic root replacement with pericardial patch repair of the LVOT abscess and saphenous vein graft from the aorta to the LAD |
| Stented | 1.53 | PVE | Redo aortic root replacement (Bentall procedure) |
| Stented | 4.08 | PVE | Redo AVR; closure of foramen ovale; closure of membranous ventricular septal defect |
| Stentless | 8.29 | SVD | Redo aortic root replacement |
| Stentless | 10.1 | SVD | Second redo aortic root replacement, mitral valve replacement, tricuspid valve repair, and exclusion of the left atrial appendage |
| Stented | 10.2 | SVD | Redo AVR |
| Stentless | 10.9 | SVD | Redo AVR and replacement of ascending aorta |
| Stentless | 11.2 | SVD | Second redo AVR |
| Stented | 11.2 | SVD | Redo AVR and replacement of the ascending aorta |
| Stentless | 13.8 | SVD | Redo aortic root and ascending aorta replacement with St Jude (St Paul, Minn) mechanical valve composite valve graft, mitral valve replacement, and left atrium patch repair |
| Stentless | 15.4 | SVD | Redo AVR |
SVD, Structural valve deterioration; PVE, prosthetic valve endocarditis; LAD, left anterior descending; LVOT, left ventricular outflow tract; AVR, aortic valve replacement.
FIGURE 3.
Freedom from reoccurrence of AVE with a stented AVR (10 years: 88%; 95% CI, 59–97) or a stentless AVR (10 years: 98%; 95% CI, 92–99.5).
DISCUSSION
In this study, we found favorable operative mortality, long-term survival, and reoperation for stented and stentless AVRs for active AVE. The key findings and implications of this study are summarized in Figure 4.
FIGURE 4.
Summary of the study, including study population of AVR of AVE, long-term survival in patients with a stented aortic valve or stentless AVR, and implications of the outcomes. Kaplan–Meier long-term survival of patients with AVE with a stented AVR (5 years: 52%; 95% CI, 40–62) or a stentless AVR (5 years: 63%; 95% CI, 55–71).
As previously stated, homografts have been the mainstay of treatment for AVE, particularly in the presence of a root abscess. In patients with homograft replacement, outcomes have been satisfactory with short-term mortality between 9.6% and 24%, and 5-year survival between 66.5% and 84%.2,4,6–8 Freedom of reoperation has also been acceptable between 74% and 92% after 10 years based on these reports. Nevertheless, AVR with a mechanical valve or bioprosthesis has been recently recognized as an acceptable alternative.1,17,21 At our institution, homograft conduits were used in the late 1990s and replaced with stentless valves (Freestyle, Medtronic, Minneapolis, Minn) in 2000 in suitable patients with endocarditis because of better accessibility and lower cost.13 Most important, we have found radical debridement of infected tissue to be the most important part of surgical treatment. This reduces the risk of reinfection and reoperation. As such, when proper debridement is used in combination with proper antibiotic use, any valve type will have a lower probability of reinfection, which allows for the use of stented and stentless bioprosthetic valves successfully.
In studies comparing stentless versus stented aortic valves, there is no clear consensus regarding which type of bioprosthesis had superior outcomes. Our study had a 30-day mortality of 4.1% in the stented valve group and 6.0% in the stentless valve group, which was consistent with prior studies that had a 30-day mortality for stented and stentless aortic valves ranging from 3.9% to 12.5% and 5.2% to 13.3%, respectively.14,15,22 Our findings indicated that although implantation of a stentless valve was more complex and required longer cardiopulmonary bypass and aortic crossclamp time, it could be done safely in patients with AVE. Particularly, in patients with aortic root abscess or root aneurysm requiring an aortic root replacement, a stentless valve was a good conduit for the aortic root reconstruction.
We report a 5-year long-term survival of 52% for the stented group and 63% for the stentless group (Figure 1). The multivariable Cox model confirmed that the use of a stented valve was not a risk factor for long-term mortality (HR, 1.18) (Table 5). As in previous studies, PVE was found to be a risk factor for operative mortality in our study.15 However, unlike in other studies, age, liver disease, previous MI, CHF, and renal failure requiring dialysis were all significant risk factors for long-term mortality. These comorbidities may have explained the lower rate of survival in our study (Tables 4 and 5) supporting the importance of earlier surgical intervention on AVE before patients develop liver disease, CHF, and renal failure. This may also provide surgeons with knowledge to further assess and screen patients as surgical candidates in this population. Our clinical practice with patients with endocarditis has been to operate sooner rather than later if there is an indication, based on the American Association for Thoracic Surgery infective endocarditis guidelines and after discussion with our multidisciplinary endocarditis team, to reduce the possibilities of developing organ failure such as CHF, liver failure, and renal failure.17,23
Our 10-year cumulative incidence of reoperation adjusted with death as a competing factor, a model not used in previous studies, was 12% for the stented group and 3.4% for the stentless valve group, indicating that either valve is a valid conduit for treatment of AVE in the long term (Figure 2). Schaefer and colleagues,14 however, reported significantly more reoperations in patients with Sorin solo stentless aortic valves due to SVD and PVE, which is a different type of stentless valve compared with the Freestyle stentless valve made by Medtronic. Furthermore, only 77 patients in Schaefer and colleagues’ study had Sorin solo stentless aortic valves compared with 168 patients who had Freestyle stemless valves in our study. In our study, the similarity of reoperation rates for SVD and PVE between groups allowed for either type of valve to be equally effective for the treatment of AVE. We also found the 10-year freedom from reoccurrence of AVE for the stented valve group to be 88% and 98% for the stentless valve group (Figure 3). Both the cumulative incidence of reoperation and freedom from reinfection indicated that stentless valve performed better, although there was no formal statistical comparison. Stentless valves have less fabric material compared with the stented valve. This could be a reason for the lower reinfection rate. Taken together, our results substantiated the critical role of extensive and thorough debridement in reducing the risk for reinfection for these patients and not the type of bioprosthetic valve.
Study Limitations
Our study is a single-center retrospective experience with all the limitations of a retrospective study. Operative procedures were fairly consistent despite the multiple surgeons at our institution over the 19-year span of the study. Nevertheless, this study provided evidence of selecting bioprosthesis for AVE with acceptable long-term survival and cumulative incidence of reoperation data.
CONCLUSIONS
Perioperative mortality and long-term survival were acceptable for patients treated with a stented aortic valve and a stentless AVR for active AVE. Additionally, there were low rates of reinfection or reoperation for the 2 groups. Thorough and extensive debridement of the infected tissue was essential in treating this disease. Both stented and stentless aortic valves are appropriate conduits for the treatment of active AVE.
Supplementary Material
CENTRAL MESSAGE.
Both stented and stentless AVRs are acceptable for AVE with favorable perioperative outcomes, long-term survival, and reoperation rate.
PERSPECTIVE.
This study adds to the limited data found on stented and stentless valve replacements for AVE. This study showed that stented or stentless valves are an acceptable prosthesis for AVE. Furthermore, extensive and thorough debridement of the infection was most important in treating the disease.
Acknowledgments
Dr Yang is supported by the National Heart, Lung, and Blood Institute of National Institutes of Health K08HL130614 and R01HL141891, and Phil Jenkins and Darlene & Stephen J. Szatmari Funds. Dr Patel is supported by the Joe D. Morris Collegiate Professorship, the David Hamilton Fund, and the Phil Jenkins Breakthrough Fund in Cardiac Surgery. Dr Deeb is supported by the Herbert Sloan Collegiate Professorship, Jamie Buhr Fund, and Richard Nerod Fund.
Abbreviations and Acronyms
- AVE
aortic valve endocarditis
- AVR
aortic valve replacement
- CHF
congestive heart failure
- CI
confidence interval
- HR
hazard ratio
- IV
intravenous
- MI
myocardial infarction
- OR
odds ratio
- PVE
prosthetic valve endocarditis
- SVD
structural valve degeneration
Footnotes
Date and Number of Institutional Review Board Approval: March 31, 2018; HUM00142927 Presentation: AHA10986
Drs Clemence and Caceres contributed equally as co-first authors.
Conflict of Interest Statement
Drs Patel and Deeb are consultants for Medtronic. All other authors reported no conflicts of interest.
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